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authorGravatar Vincent Rischmann2022-09-11 17:37:46 +0200
committerGravatar Vincent Rischmann2022-09-18 02:30:19 +0200
commitf7c42e6259497ae6492d81a998a6157ef9498d6a (patch)
treef7746f1c4204e5bc279defe7a52a27c8caeb843d /c
parentbuild: add the preprocess-files tool (diff)
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c: add header files specifically for building loadable extensions
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-rw-r--r--c/loadable-ext-sqlite3.h12037
-rw-r--r--c/loadable-ext-sqlite3ext.h433
2 files changed, 12470 insertions, 0 deletions
diff --git a/c/loadable-ext-sqlite3.h b/c/loadable-ext-sqlite3.h
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1/*
2** 2001-09-15
3**
4** The author disclaims copyright to this source code. In place of
5** a legal notice, here is a blessing:
6**
7** May you do good and not evil.
8** May you find forgiveness for yourself and forgive others.
9** May you share freely, never taking more than you give.
10**
11*************************************************************************
12** This header file defines the interface that the SQLite library
13** presents to client programs. If a C-function, structure, datatype,
14** or constant definition does not appear in this file, then it is
15** not a published API of SQLite, is subject to change without
16** notice, and should not be referenced by programs that use SQLite.
17**
18** Some of the definitions that are in this file are marked as
19** "experimental". Experimental interfaces are normally new
20** features recently added to SQLite. We do not anticipate changes
21** to experimental interfaces but reserve the right to make minor changes
22** if experience from use "in the wild" suggest such changes are prudent.
23**
24** The official C-language API documentation for SQLite is derived
25** from comments in this file. This file is the authoritative source
26** on how SQLite interfaces are supposed to operate.
27**
28** The name of this file under configuration management is "sqlite.h.in".
29** The makefile makes some minor changes to this file (such as inserting
30** the version number) and changes its name to "sqlite3.h" as
31** part of the build process.
32*/
33#ifndef SQLITE3_H
34#define SQLITE3_H
35#include <stdarg.h> /* Needed for the definition of va_list */
36
37/*
38** Make sure we can call this stuff from C++.
39*/
40#ifdef __cplusplus
41extern "C" {
42#endif
43
44
45/*
46** Facilitate override of interface linkage and calling conventions.
47** Be aware that these macros may not be used within this particular
48** translation of the amalgamation and its associated header file.
49**
50** The SQLITE_EXTERN and SQLITE_API macros are used to instruct the
51** compiler that the target identifier should have external linkage.
52**
53** The SQLITE_CDECL macro is used to set the calling convention for
54** public functions that accept a variable number of arguments.
55**
56** The SQLITE_APICALL macro is used to set the calling convention for
57** public functions that accept a fixed number of arguments.
58**
59** The SQLITE_STDCALL macro is no longer used and is now deprecated.
60**
61** The SQLITE_CALLBACK macro is used to set the calling convention for
62** function pointers.
63**
64** The SQLITE_SYSAPI macro is used to set the calling convention for
65** functions provided by the operating system.
66**
67** Currently, the SQLITE_CDECL, SQLITE_APICALL, SQLITE_CALLBACK, and
68** SQLITE_SYSAPI macros are used only when building for environments
69** that require non-default calling conventions.
70*/
71#ifndef SQLITE_EXTERN
72# define SQLITE_EXTERN extern
73#endif
74#ifndef SQLITE_API
75# define SQLITE_API
76#endif
77#ifndef SQLITE_CDECL
78# define SQLITE_CDECL
79#endif
80#ifndef SQLITE_APICALL
81# define SQLITE_APICALL
82#endif
83#ifndef SQLITE_STDCALL
84# define SQLITE_STDCALL SQLITE_APICALL
85#endif
86#ifndef SQLITE_CALLBACK
87# define SQLITE_CALLBACK
88#endif
89#ifndef SQLITE_SYSAPI
90# define SQLITE_SYSAPI
91#endif
92
93/*
94** These no-op macros are used in front of interfaces to mark those
95** interfaces as either deprecated or experimental. New applications
96** should not use deprecated interfaces - they are supported for backwards
97** compatibility only. Application writers should be aware that
98** experimental interfaces are subject to change in point releases.
99**
100** These macros used to resolve to various kinds of compiler magic that
101** would generate warning messages when they were used. But that
102** compiler magic ended up generating such a flurry of bug reports
103** that we have taken it all out and gone back to using simple
104** noop macros.
105*/
106#define SQLITE_DEPRECATED
107#define SQLITE_EXPERIMENTAL
108
109/*
110** Ensure these symbols were not defined by some previous header file.
111*/
112#ifdef SQLITE_VERSION
113# undef SQLITE_VERSION
114#endif
115#ifdef SQLITE_VERSION_NUMBER
116# undef SQLITE_VERSION_NUMBER
117#endif
118
119/*
120** CAPI3REF: Compile-Time Library Version Numbers
121**
122** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
123** evaluates to a string literal that is the SQLite version in the
124** format "X.Y.Z" where X is the major version number (always 3 for
125** SQLite3) and Y is the minor version number and Z is the release number.)^
126** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
127** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
128** numbers used in [SQLITE_VERSION].)^
129** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
130** be larger than the release from which it is derived. Either Y will
131** be held constant and Z will be incremented or else Y will be incremented
132** and Z will be reset to zero.
133**
134** Since [version 3.6.18] ([dateof:3.6.18]),
135** SQLite source code has been stored in the
136** <a href="http://www.fossil-scm.org/">Fossil configuration management
137** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to
138** a string which identifies a particular check-in of SQLite
139** within its configuration management system. ^The SQLITE_SOURCE_ID
140** string contains the date and time of the check-in (UTC) and a SHA1
141** or SHA3-256 hash of the entire source tree. If the source code has
142** been edited in any way since it was last checked in, then the last
143** four hexadecimal digits of the hash may be modified.
144**
145** See also: [sqlite3_libversion()],
146** [sqlite3_libversion_number()], [sqlite3_sourceid()],
147** [sqlite_version()] and [sqlite_source_id()].
148*/
149#define SQLITE_VERSION "3.39.3"
150#define SQLITE_VERSION_NUMBER 3039003
151#define SQLITE_SOURCE_ID "2022-09-05 11:02:23 4635f4a69c8c2a8df242b384a992aea71224e39a2ccab42d8c0b0602f1e826e8"
152
153/*
154** CAPI3REF: Run-Time Library Version Numbers
155** KEYWORDS: sqlite3_version sqlite3_sourceid
156**
157** These interfaces provide the same information as the [SQLITE_VERSION],
158** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
159** but are associated with the library instead of the header file. ^(Cautious
160** programmers might include assert() statements in their application to
161** verify that values returned by these interfaces match the macros in
162** the header, and thus ensure that the application is
163** compiled with matching library and header files.
164**
165** <blockquote><pre>
166** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
167** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
168** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
169** </pre></blockquote>)^
170**
171** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
172** macro. ^The sqlite3_libversion() function returns a pointer to the
173** to the sqlite3_version[] string constant. The sqlite3_libversion()
174** function is provided for use in DLLs since DLL users usually do not have
175** direct access to string constants within the DLL. ^The
176** sqlite3_libversion_number() function returns an integer equal to
177** [SQLITE_VERSION_NUMBER]. ^(The sqlite3_sourceid() function returns
178** a pointer to a string constant whose value is the same as the
179** [SQLITE_SOURCE_ID] C preprocessor macro. Except if SQLite is built
180** using an edited copy of [the amalgamation], then the last four characters
181** of the hash might be different from [SQLITE_SOURCE_ID].)^
182**
183** See also: [sqlite_version()] and [sqlite_source_id()].
184*/
185SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
186
187/*
188** CAPI3REF: Run-Time Library Compilation Options Diagnostics
189**
190** ^The sqlite3_compileoption_used() function returns 0 or 1
191** indicating whether the specified option was defined at
192** compile time. ^The SQLITE_ prefix may be omitted from the
193** option name passed to sqlite3_compileoption_used().
194**
195** ^The sqlite3_compileoption_get() function allows iterating
196** over the list of options that were defined at compile time by
197** returning the N-th compile time option string. ^If N is out of range,
198** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
199** prefix is omitted from any strings returned by
200** sqlite3_compileoption_get().
201**
202** ^Support for the diagnostic functions sqlite3_compileoption_used()
203** and sqlite3_compileoption_get() may be omitted by specifying the
204** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
205**
206** See also: SQL functions [sqlite_compileoption_used()] and
207** [sqlite_compileoption_get()] and the [compile_options pragma].
208*/
209#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
210#else
211# define sqlite3_compileoption_used(X) 0
212# define sqlite3_compileoption_get(X) ((void*)0)
213#endif
214
215/*
216** CAPI3REF: Test To See If The Library Is Threadsafe
217**
218** ^The sqlite3_threadsafe() function returns zero if and only if
219** SQLite was compiled with mutexing code omitted due to the
220** [SQLITE_THREADSAFE] compile-time option being set to 0.
221**
222** SQLite can be compiled with or without mutexes. When
223** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
224** are enabled and SQLite is threadsafe. When the
225** [SQLITE_THREADSAFE] macro is 0,
226** the mutexes are omitted. Without the mutexes, it is not safe
227** to use SQLite concurrently from more than one thread.
228**
229** Enabling mutexes incurs a measurable performance penalty.
230** So if speed is of utmost importance, it makes sense to disable
231** the mutexes. But for maximum safety, mutexes should be enabled.
232** ^The default behavior is for mutexes to be enabled.
233**
234** This interface can be used by an application to make sure that the
235** version of SQLite that it is linking against was compiled with
236** the desired setting of the [SQLITE_THREADSAFE] macro.
237**
238** This interface only reports on the compile-time mutex setting
239** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
240** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
241** can be fully or partially disabled using a call to [sqlite3_config()]
242** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
243** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the
244** sqlite3_threadsafe() function shows only the compile-time setting of
245** thread safety, not any run-time changes to that setting made by
246** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
247** is unchanged by calls to sqlite3_config().)^
248**
249** See the [threading mode] documentation for additional information.
250*/
251
252/*
253** CAPI3REF: Database Connection Handle
254** KEYWORDS: {database connection} {database connections}
255**
256** Each open SQLite database is represented by a pointer to an instance of
257** the opaque structure named "sqlite3". It is useful to think of an sqlite3
258** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
259** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
260** and [sqlite3_close_v2()] are its destructors. There are many other
261** interfaces (such as
262** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
263** [sqlite3_busy_timeout()] to name but three) that are methods on an
264** sqlite3 object.
265*/
266typedef struct sqlite3 sqlite3;
267
268/*
269** CAPI3REF: 64-Bit Integer Types
270** KEYWORDS: sqlite_int64 sqlite_uint64
271**
272** Because there is no cross-platform way to specify 64-bit integer types
273** SQLite includes typedefs for 64-bit signed and unsigned integers.
274**
275** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
276** The sqlite_int64 and sqlite_uint64 types are supported for backwards
277** compatibility only.
278**
279** ^The sqlite3_int64 and sqlite_int64 types can store integer values
280** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
281** sqlite3_uint64 and sqlite_uint64 types can store integer values
282** between 0 and +18446744073709551615 inclusive.
283*/
284#ifdef SQLITE_INT64_TYPE
285 typedef SQLITE_INT64_TYPE sqlite_int64;
286# ifdef SQLITE_UINT64_TYPE
287 typedef SQLITE_UINT64_TYPE sqlite_uint64;
288# else
289 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
290# endif
291#elif defined(_MSC_VER) || defined(__BORLANDC__)
292 typedef __int64 sqlite_int64;
293 typedef unsigned __int64 sqlite_uint64;
294#else
295 typedef long long int sqlite_int64;
296 typedef unsigned long long int sqlite_uint64;
297#endif
298typedef sqlite_int64 sqlite3_int64;
299typedef sqlite_uint64 sqlite3_uint64;
300
301/*
302** If compiling for a processor that lacks floating point support,
303** substitute integer for floating-point.
304*/
305#ifdef SQLITE_OMIT_FLOATING_POINT
306# define double sqlite3_int64
307#endif
308
309/*
310** CAPI3REF: Closing A Database Connection
311** DESTRUCTOR: sqlite3
312**
313** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
314** for the [sqlite3] object.
315** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
316** the [sqlite3] object is successfully destroyed and all associated
317** resources are deallocated.
318**
319** Ideally, applications should [sqlite3_finalize | finalize] all
320** [prepared statements], [sqlite3_blob_close | close] all [BLOB handles], and
321** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
322** with the [sqlite3] object prior to attempting to close the object.
323** ^If the database connection is associated with unfinalized prepared
324** statements, BLOB handlers, and/or unfinished sqlite3_backup objects then
325** sqlite3_close() will leave the database connection open and return
326** [SQLITE_BUSY]. ^If sqlite3_close_v2() is called with unfinalized prepared
327** statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups,
328** it returns [SQLITE_OK] regardless, but instead of deallocating the database
329** connection immediately, it marks the database connection as an unusable
330** "zombie" and makes arrangements to automatically deallocate the database
331** connection after all prepared statements are finalized, all BLOB handles
332** are closed, and all backups have finished. The sqlite3_close_v2() interface
333** is intended for use with host languages that are garbage collected, and
334** where the order in which destructors are called is arbitrary.
335**
336** ^If an [sqlite3] object is destroyed while a transaction is open,
337** the transaction is automatically rolled back.
338**
339** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
340** must be either a NULL
341** pointer or an [sqlite3] object pointer obtained
342** from [sqlite3_open()], [sqlite3_open16()], or
343** [sqlite3_open_v2()], and not previously closed.
344** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
345** argument is a harmless no-op.
346*/
347
348/*
349** The type for a callback function.
350** This is legacy and deprecated. It is included for historical
351** compatibility and is not documented.
352*/
353typedef int (*sqlite3_callback)(void*,int,char**, char**);
354
355/*
356** CAPI3REF: One-Step Query Execution Interface
357** METHOD: sqlite3
358**
359** The sqlite3_exec() interface is a convenience wrapper around
360** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
361** that allows an application to run multiple statements of SQL
362** without having to use a lot of C code.
363**
364** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
365** semicolon-separate SQL statements passed into its 2nd argument,
366** in the context of the [database connection] passed in as its 1st
367** argument. ^If the callback function of the 3rd argument to
368** sqlite3_exec() is not NULL, then it is invoked for each result row
369** coming out of the evaluated SQL statements. ^The 4th argument to
370** sqlite3_exec() is relayed through to the 1st argument of each
371** callback invocation. ^If the callback pointer to sqlite3_exec()
372** is NULL, then no callback is ever invoked and result rows are
373** ignored.
374**
375** ^If an error occurs while evaluating the SQL statements passed into
376** sqlite3_exec(), then execution of the current statement stops and
377** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
378** is not NULL then any error message is written into memory obtained
379** from [sqlite3_malloc()] and passed back through the 5th parameter.
380** To avoid memory leaks, the application should invoke [sqlite3_free()]
381** on error message strings returned through the 5th parameter of
382** sqlite3_exec() after the error message string is no longer needed.
383** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
384** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
385** NULL before returning.
386**
387** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
388** routine returns SQLITE_ABORT without invoking the callback again and
389** without running any subsequent SQL statements.
390**
391** ^The 2nd argument to the sqlite3_exec() callback function is the
392** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
393** callback is an array of pointers to strings obtained as if from
394** [sqlite3_column_text()], one for each column. ^If an element of a
395** result row is NULL then the corresponding string pointer for the
396** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
397** sqlite3_exec() callback is an array of pointers to strings where each
398** entry represents the name of corresponding result column as obtained
399** from [sqlite3_column_name()].
400**
401** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
402** to an empty string, or a pointer that contains only whitespace and/or
403** SQL comments, then no SQL statements are evaluated and the database
404** is not changed.
405**
406** Restrictions:
407**
408** <ul>
409** <li> The application must ensure that the 1st parameter to sqlite3_exec()
410** is a valid and open [database connection].
411** <li> The application must not close the [database connection] specified by
412** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
413** <li> The application must not modify the SQL statement text passed into
414** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
415** </ul>
416*/
417
418/*
419** CAPI3REF: Result Codes
420** KEYWORDS: {result code definitions}
421**
422** Many SQLite functions return an integer result code from the set shown
423** here in order to indicate success or failure.
424**
425** New error codes may be added in future versions of SQLite.
426**
427** See also: [extended result code definitions]
428*/
429#define SQLITE_OK 0 /* Successful result */
430/* beginning-of-error-codes */
431#define SQLITE_ERROR 1 /* Generic error */
432#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
433#define SQLITE_PERM 3 /* Access permission denied */
434#define SQLITE_ABORT 4 /* Callback routine requested an abort */
435#define SQLITE_BUSY 5 /* The database file is locked */
436#define SQLITE_LOCKED 6 /* A table in the database is locked */
437#define SQLITE_NOMEM 7 /* A malloc() failed */
438#define SQLITE_READONLY 8 /* Attempt to write a readonly database */
439#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
440#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
441#define SQLITE_CORRUPT 11 /* The database disk image is malformed */
442#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
443#define SQLITE_FULL 13 /* Insertion failed because database is full */
444#define SQLITE_CANTOPEN 14 /* Unable to open the database file */
445#define SQLITE_PROTOCOL 15 /* Database lock protocol error */
446#define SQLITE_EMPTY 16 /* Internal use only */
447#define SQLITE_SCHEMA 17 /* The database schema changed */
448#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
449#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
450#define SQLITE_MISMATCH 20 /* Data type mismatch */
451#define SQLITE_MISUSE 21 /* Library used incorrectly */
452#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
453#define SQLITE_AUTH 23 /* Authorization denied */
454#define SQLITE_FORMAT 24 /* Not used */
455#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
456#define SQLITE_NOTADB 26 /* File opened that is not a database file */
457#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */
458#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */
459#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
460#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
461/* end-of-error-codes */
462
463/*
464** CAPI3REF: Extended Result Codes
465** KEYWORDS: {extended result code definitions}
466**
467** In its default configuration, SQLite API routines return one of 30 integer
468** [result codes]. However, experience has shown that many of
469** these result codes are too coarse-grained. They do not provide as
470** much information about problems as programmers might like. In an effort to
471** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
472** and later) include
473** support for additional result codes that provide more detailed information
474** about errors. These [extended result codes] are enabled or disabled
475** on a per database connection basis using the
476** [sqlite3_extended_result_codes()] API. Or, the extended code for
477** the most recent error can be obtained using
478** [sqlite3_extended_errcode()].
479*/
480#define SQLITE_ERROR_MISSING_COLLSEQ (SQLITE_ERROR | (1<<8))
481#define SQLITE_ERROR_RETRY (SQLITE_ERROR | (2<<8))
482#define SQLITE_ERROR_SNAPSHOT (SQLITE_ERROR | (3<<8))
483#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
484#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
485#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
486#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
487#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
488#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
489#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
490#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
491#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
492#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
493#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
494#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
495#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
496#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
497#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
498#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
499#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
500#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
501#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
502#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
503#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
504#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
505#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
506#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
507#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8))
508#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8))
509#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8))
510#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8))
511#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8))
512#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8))
513#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8))
514#define SQLITE_IOERR_DATA (SQLITE_IOERR | (32<<8))
515#define SQLITE_IOERR_CORRUPTFS (SQLITE_IOERR | (33<<8))
516#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
517#define SQLITE_LOCKED_VTAB (SQLITE_LOCKED | (2<<8))
518#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
519#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8))
520#define SQLITE_BUSY_TIMEOUT (SQLITE_BUSY | (3<<8))
521#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
522#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
523#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
524#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8))
525#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
526#define SQLITE_CANTOPEN_SYMLINK (SQLITE_CANTOPEN | (6<<8))
527#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
528#define SQLITE_CORRUPT_SEQUENCE (SQLITE_CORRUPT | (2<<8))
529#define SQLITE_CORRUPT_INDEX (SQLITE_CORRUPT | (3<<8))
530#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
531#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
532#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8))
533#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8))
534#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8))
535#define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8))
536#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
537#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8))
538#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8))
539#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8))
540#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8))
541#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8))
542#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8))
543#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8))
544#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8))
545#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8))
546#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8))
547#define SQLITE_CONSTRAINT_PINNED (SQLITE_CONSTRAINT |(11<<8))
548#define SQLITE_CONSTRAINT_DATATYPE (SQLITE_CONSTRAINT |(12<<8))
549#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8))
550#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
551#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8))
552#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8))
553#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8))
554#define SQLITE_OK_SYMLINK (SQLITE_OK | (2<<8)) /* internal use only */
555
556/*
557** CAPI3REF: Flags For File Open Operations
558**
559** These bit values are intended for use in the
560** 3rd parameter to the [sqlite3_open_v2()] interface and
561** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
562**
563** Only those flags marked as "Ok for sqlite3_open_v2()" may be
564** used as the third argument to the [sqlite3_open_v2()] interface.
565** The other flags have historically been ignored by sqlite3_open_v2(),
566** though future versions of SQLite might change so that an error is
567** raised if any of the disallowed bits are passed into sqlite3_open_v2().
568** Applications should not depend on the historical behavior.
569**
570** Note in particular that passing the SQLITE_OPEN_EXCLUSIVE flag into
571** [sqlite3_open_v2()] does *not* cause the underlying database file
572** to be opened using O_EXCL. Passing SQLITE_OPEN_EXCLUSIVE into
573** [sqlite3_open_v2()] has historically be a no-op and might become an
574** error in future versions of SQLite.
575*/
576#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
577#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
578#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
579#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
580#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
581#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
582#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
583#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
584#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
585#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
586#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
587#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
588#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
589#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
590#define SQLITE_OPEN_SUPER_JOURNAL 0x00004000 /* VFS only */
591#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
592#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
593#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
594#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
595#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
596#define SQLITE_OPEN_NOFOLLOW 0x01000000 /* Ok for sqlite3_open_v2() */
597#define SQLITE_OPEN_EXRESCODE 0x02000000 /* Extended result codes */
598
599/* Reserved: 0x00F00000 */
600/* Legacy compatibility: */
601#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
602
603
604/*
605** CAPI3REF: Device Characteristics
606**
607** The xDeviceCharacteristics method of the [sqlite3_io_methods]
608** object returns an integer which is a vector of these
609** bit values expressing I/O characteristics of the mass storage
610** device that holds the file that the [sqlite3_io_methods]
611** refers to.
612**
613** The SQLITE_IOCAP_ATOMIC property means that all writes of
614** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
615** mean that writes of blocks that are nnn bytes in size and
616** are aligned to an address which is an integer multiple of
617** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
618** that when data is appended to a file, the data is appended
619** first then the size of the file is extended, never the other
620** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
621** information is written to disk in the same order as calls
622** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
623** after reboot following a crash or power loss, the only bytes in a
624** file that were written at the application level might have changed
625** and that adjacent bytes, even bytes within the same sector are
626** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
627** flag indicates that a file cannot be deleted when open. The
628** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
629** read-only media and cannot be changed even by processes with
630** elevated privileges.
631**
632** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
633** filesystem supports doing multiple write operations atomically when those
634** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
635** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
636*/
637#define SQLITE_IOCAP_ATOMIC 0x00000001
638#define SQLITE_IOCAP_ATOMIC512 0x00000002
639#define SQLITE_IOCAP_ATOMIC1K 0x00000004
640#define SQLITE_IOCAP_ATOMIC2K 0x00000008
641#define SQLITE_IOCAP_ATOMIC4K 0x00000010
642#define SQLITE_IOCAP_ATOMIC8K 0x00000020
643#define SQLITE_IOCAP_ATOMIC16K 0x00000040
644#define SQLITE_IOCAP_ATOMIC32K 0x00000080
645#define SQLITE_IOCAP_ATOMIC64K 0x00000100
646#define SQLITE_IOCAP_SAFE_APPEND 0x00000200
647#define SQLITE_IOCAP_SEQUENTIAL 0x00000400
648#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
649#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
650#define SQLITE_IOCAP_IMMUTABLE 0x00002000
651#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000
652
653/*
654** CAPI3REF: File Locking Levels
655**
656** SQLite uses one of these integer values as the second
657** argument to calls it makes to the xLock() and xUnlock() methods
658** of an [sqlite3_io_methods] object.
659*/
660#define SQLITE_LOCK_NONE 0
661#define SQLITE_LOCK_SHARED 1
662#define SQLITE_LOCK_RESERVED 2
663#define SQLITE_LOCK_PENDING 3
664#define SQLITE_LOCK_EXCLUSIVE 4
665
666/*
667** CAPI3REF: Synchronization Type Flags
668**
669** When SQLite invokes the xSync() method of an
670** [sqlite3_io_methods] object it uses a combination of
671** these integer values as the second argument.
672**
673** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
674** sync operation only needs to flush data to mass storage. Inode
675** information need not be flushed. If the lower four bits of the flag
676** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
677** If the lower four bits equal SQLITE_SYNC_FULL, that means
678** to use Mac OS X style fullsync instead of fsync().
679**
680** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
681** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
682** settings. The [synchronous pragma] determines when calls to the
683** xSync VFS method occur and applies uniformly across all platforms.
684** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
685** energetic or rigorous or forceful the sync operations are and
686** only make a difference on Mac OSX for the default SQLite code.
687** (Third-party VFS implementations might also make the distinction
688** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
689** operating systems natively supported by SQLite, only Mac OSX
690** cares about the difference.)
691*/
692#define SQLITE_SYNC_NORMAL 0x00002
693#define SQLITE_SYNC_FULL 0x00003
694#define SQLITE_SYNC_DATAONLY 0x00010
695
696/*
697** CAPI3REF: OS Interface Open File Handle
698**
699** An [sqlite3_file] object represents an open file in the
700** [sqlite3_vfs | OS interface layer]. Individual OS interface
701** implementations will
702** want to subclass this object by appending additional fields
703** for their own use. The pMethods entry is a pointer to an
704** [sqlite3_io_methods] object that defines methods for performing
705** I/O operations on the open file.
706*/
707typedef struct sqlite3_file sqlite3_file;
708struct sqlite3_file {
709 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
710};
711
712/*
713** CAPI3REF: OS Interface File Virtual Methods Object
714**
715** Every file opened by the [sqlite3_vfs.xOpen] method populates an
716** [sqlite3_file] object (or, more commonly, a subclass of the
717** [sqlite3_file] object) with a pointer to an instance of this object.
718** This object defines the methods used to perform various operations
719** against the open file represented by the [sqlite3_file] object.
720**
721** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
722** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
723** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
724** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
725** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
726** to NULL.
727**
728** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
729** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
730** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
731** flag may be ORed in to indicate that only the data of the file
732** and not its inode needs to be synced.
733**
734** The integer values to xLock() and xUnlock() are one of
735** <ul>
736** <li> [SQLITE_LOCK_NONE],
737** <li> [SQLITE_LOCK_SHARED],
738** <li> [SQLITE_LOCK_RESERVED],
739** <li> [SQLITE_LOCK_PENDING], or
740** <li> [SQLITE_LOCK_EXCLUSIVE].
741** </ul>
742** xLock() increases the lock. xUnlock() decreases the lock.
743** The xCheckReservedLock() method checks whether any database connection,
744** either in this process or in some other process, is holding a RESERVED,
745** PENDING, or EXCLUSIVE lock on the file. It returns true
746** if such a lock exists and false otherwise.
747**
748** The xFileControl() method is a generic interface that allows custom
749** VFS implementations to directly control an open file using the
750** [sqlite3_file_control()] interface. The second "op" argument is an
751** integer opcode. The third argument is a generic pointer intended to
752** point to a structure that may contain arguments or space in which to
753** write return values. Potential uses for xFileControl() might be
754** functions to enable blocking locks with timeouts, to change the
755** locking strategy (for example to use dot-file locks), to inquire
756** about the status of a lock, or to break stale locks. The SQLite
757** core reserves all opcodes less than 100 for its own use.
758** A [file control opcodes | list of opcodes] less than 100 is available.
759** Applications that define a custom xFileControl method should use opcodes
760** greater than 100 to avoid conflicts. VFS implementations should
761** return [SQLITE_NOTFOUND] for file control opcodes that they do not
762** recognize.
763**
764** The xSectorSize() method returns the sector size of the
765** device that underlies the file. The sector size is the
766** minimum write that can be performed without disturbing
767** other bytes in the file. The xDeviceCharacteristics()
768** method returns a bit vector describing behaviors of the
769** underlying device:
770**
771** <ul>
772** <li> [SQLITE_IOCAP_ATOMIC]
773** <li> [SQLITE_IOCAP_ATOMIC512]
774** <li> [SQLITE_IOCAP_ATOMIC1K]
775** <li> [SQLITE_IOCAP_ATOMIC2K]
776** <li> [SQLITE_IOCAP_ATOMIC4K]
777** <li> [SQLITE_IOCAP_ATOMIC8K]
778** <li> [SQLITE_IOCAP_ATOMIC16K]
779** <li> [SQLITE_IOCAP_ATOMIC32K]
780** <li> [SQLITE_IOCAP_ATOMIC64K]
781** <li> [SQLITE_IOCAP_SAFE_APPEND]
782** <li> [SQLITE_IOCAP_SEQUENTIAL]
783** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
784** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
785** <li> [SQLITE_IOCAP_IMMUTABLE]
786** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
787** </ul>
788**
789** The SQLITE_IOCAP_ATOMIC property means that all writes of
790** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
791** mean that writes of blocks that are nnn bytes in size and
792** are aligned to an address which is an integer multiple of
793** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
794** that when data is appended to a file, the data is appended
795** first then the size of the file is extended, never the other
796** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
797** information is written to disk in the same order as calls
798** to xWrite().
799**
800** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
801** in the unread portions of the buffer with zeros. A VFS that
802** fails to zero-fill short reads might seem to work. However,
803** failure to zero-fill short reads will eventually lead to
804** database corruption.
805*/
806typedef struct sqlite3_io_methods sqlite3_io_methods;
807struct sqlite3_io_methods {
808 int iVersion;
809 int (*xClose)(sqlite3_file*);
810 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
811 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
812 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
813 int (*xSync)(sqlite3_file*, int flags);
814 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
815 int (*xLock)(sqlite3_file*, int);
816 int (*xUnlock)(sqlite3_file*, int);
817 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
818 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
819 int (*xSectorSize)(sqlite3_file*);
820 int (*xDeviceCharacteristics)(sqlite3_file*);
821 /* Methods above are valid for version 1 */
822 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
823 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
824 void (*xShmBarrier)(sqlite3_file*);
825 int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
826 /* Methods above are valid for version 2 */
827 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
828 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
829 /* Methods above are valid for version 3 */
830 /* Additional methods may be added in future releases */
831};
832
833/*
834** CAPI3REF: Standard File Control Opcodes
835** KEYWORDS: {file control opcodes} {file control opcode}
836**
837** These integer constants are opcodes for the xFileControl method
838** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
839** interface.
840**
841** <ul>
842** <li>[[SQLITE_FCNTL_LOCKSTATE]]
843** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
844** opcode causes the xFileControl method to write the current state of
845** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
846** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
847** into an integer that the pArg argument points to. This capability
848** is used during testing and is only available when the SQLITE_TEST
849** compile-time option is used.
850**
851** <li>[[SQLITE_FCNTL_SIZE_HINT]]
852** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
853** layer a hint of how large the database file will grow to be during the
854** current transaction. This hint is not guaranteed to be accurate but it
855** is often close. The underlying VFS might choose to preallocate database
856** file space based on this hint in order to help writes to the database
857** file run faster.
858**
859** <li>[[SQLITE_FCNTL_SIZE_LIMIT]]
860** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that
861** implements [sqlite3_deserialize()] to set an upper bound on the size
862** of the in-memory database. The argument is a pointer to a [sqlite3_int64].
863** If the integer pointed to is negative, then it is filled in with the
864** current limit. Otherwise the limit is set to the larger of the value
865** of the integer pointed to and the current database size. The integer
866** pointed to is set to the new limit.
867**
868** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
869** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
870** extends and truncates the database file in chunks of a size specified
871** by the user. The fourth argument to [sqlite3_file_control()] should
872** point to an integer (type int) containing the new chunk-size to use
873** for the nominated database. Allocating database file space in large
874** chunks (say 1MB at a time), may reduce file-system fragmentation and
875** improve performance on some systems.
876**
877** <li>[[SQLITE_FCNTL_FILE_POINTER]]
878** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
879** to the [sqlite3_file] object associated with a particular database
880** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER].
881**
882** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
883** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
884** to the [sqlite3_file] object associated with the journal file (either
885** the [rollback journal] or the [write-ahead log]) for a particular database
886** connection. See also [SQLITE_FCNTL_FILE_POINTER].
887**
888** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
889** No longer in use.
890**
891** <li>[[SQLITE_FCNTL_SYNC]]
892** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
893** sent to the VFS immediately before the xSync method is invoked on a
894** database file descriptor. Or, if the xSync method is not invoked
895** because the user has configured SQLite with
896** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
897** of the xSync method. In most cases, the pointer argument passed with
898** this file-control is NULL. However, if the database file is being synced
899** as part of a multi-database commit, the argument points to a nul-terminated
900** string containing the transactions super-journal file name. VFSes that
901** do not need this signal should silently ignore this opcode. Applications
902** should not call [sqlite3_file_control()] with this opcode as doing so may
903** disrupt the operation of the specialized VFSes that do require it.
904**
905** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
906** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
907** and sent to the VFS after a transaction has been committed immediately
908** but before the database is unlocked. VFSes that do not need this signal
909** should silently ignore this opcode. Applications should not call
910** [sqlite3_file_control()] with this opcode as doing so may disrupt the
911** operation of the specialized VFSes that do require it.
912**
913** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
914** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
915** retry counts and intervals for certain disk I/O operations for the
916** windows [VFS] in order to provide robustness in the presence of
917** anti-virus programs. By default, the windows VFS will retry file read,
918** file write, and file delete operations up to 10 times, with a delay
919** of 25 milliseconds before the first retry and with the delay increasing
920** by an additional 25 milliseconds with each subsequent retry. This
921** opcode allows these two values (10 retries and 25 milliseconds of delay)
922** to be adjusted. The values are changed for all database connections
923** within the same process. The argument is a pointer to an array of two
924** integers where the first integer is the new retry count and the second
925** integer is the delay. If either integer is negative, then the setting
926** is not changed but instead the prior value of that setting is written
927** into the array entry, allowing the current retry settings to be
928** interrogated. The zDbName parameter is ignored.
929**
930** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
931** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
932** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
933** write ahead log ([WAL file]) and shared memory
934** files used for transaction control
935** are automatically deleted when the latest connection to the database
936** closes. Setting persistent WAL mode causes those files to persist after
937** close. Persisting the files is useful when other processes that do not
938** have write permission on the directory containing the database file want
939** to read the database file, as the WAL and shared memory files must exist
940** in order for the database to be readable. The fourth parameter to
941** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
942** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
943** WAL mode. If the integer is -1, then it is overwritten with the current
944** WAL persistence setting.
945**
946** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
947** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
948** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
949** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
950** xDeviceCharacteristics methods. The fourth parameter to
951** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
952** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
953** mode. If the integer is -1, then it is overwritten with the current
954** zero-damage mode setting.
955**
956** <li>[[SQLITE_FCNTL_OVERWRITE]]
957** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
958** a write transaction to indicate that, unless it is rolled back for some
959** reason, the entire database file will be overwritten by the current
960** transaction. This is used by VACUUM operations.
961**
962** <li>[[SQLITE_FCNTL_VFSNAME]]
963** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
964** all [VFSes] in the VFS stack. The names are of all VFS shims and the
965** final bottom-level VFS are written into memory obtained from
966** [sqlite3_malloc()] and the result is stored in the char* variable
967** that the fourth parameter of [sqlite3_file_control()] points to.
968** The caller is responsible for freeing the memory when done. As with
969** all file-control actions, there is no guarantee that this will actually
970** do anything. Callers should initialize the char* variable to a NULL
971** pointer in case this file-control is not implemented. This file-control
972** is intended for diagnostic use only.
973**
974** <li>[[SQLITE_FCNTL_VFS_POINTER]]
975** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
976** [VFSes] currently in use. ^(The argument X in
977** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
978** of type "[sqlite3_vfs] **". This opcodes will set *X
979** to a pointer to the top-level VFS.)^
980** ^When there are multiple VFS shims in the stack, this opcode finds the
981** upper-most shim only.
982**
983** <li>[[SQLITE_FCNTL_PRAGMA]]
984** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
985** file control is sent to the open [sqlite3_file] object corresponding
986** to the database file to which the pragma statement refers. ^The argument
987** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
988** pointers to strings (char**) in which the second element of the array
989** is the name of the pragma and the third element is the argument to the
990** pragma or NULL if the pragma has no argument. ^The handler for an
991** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
992** of the char** argument point to a string obtained from [sqlite3_mprintf()]
993** or the equivalent and that string will become the result of the pragma or
994** the error message if the pragma fails. ^If the
995** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
996** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
997** file control returns [SQLITE_OK], then the parser assumes that the
998** VFS has handled the PRAGMA itself and the parser generates a no-op
999** prepared statement if result string is NULL, or that returns a copy
1000** of the result string if the string is non-NULL.
1001** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
1002** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
1003** that the VFS encountered an error while handling the [PRAGMA] and the
1004** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
1005** file control occurs at the beginning of pragma statement analysis and so
1006** it is able to override built-in [PRAGMA] statements.
1007**
1008** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
1009** ^The [SQLITE_FCNTL_BUSYHANDLER]
1010** file-control may be invoked by SQLite on the database file handle
1011** shortly after it is opened in order to provide a custom VFS with access
1012** to the connection's busy-handler callback. The argument is of type (void**)
1013** - an array of two (void *) values. The first (void *) actually points
1014** to a function of type (int (*)(void *)). In order to invoke the connection's
1015** busy-handler, this function should be invoked with the second (void *) in
1016** the array as the only argument. If it returns non-zero, then the operation
1017** should be retried. If it returns zero, the custom VFS should abandon the
1018** current operation.
1019**
1020** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
1021** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
1022** to have SQLite generate a
1023** temporary filename using the same algorithm that is followed to generate
1024** temporary filenames for TEMP tables and other internal uses. The
1025** argument should be a char** which will be filled with the filename
1026** written into memory obtained from [sqlite3_malloc()]. The caller should
1027** invoke [sqlite3_free()] on the result to avoid a memory leak.
1028**
1029** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
1030** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
1031** maximum number of bytes that will be used for memory-mapped I/O.
1032** The argument is a pointer to a value of type sqlite3_int64 that
1033** is an advisory maximum number of bytes in the file to memory map. The
1034** pointer is overwritten with the old value. The limit is not changed if
1035** the value originally pointed to is negative, and so the current limit
1036** can be queried by passing in a pointer to a negative number. This
1037** file-control is used internally to implement [PRAGMA mmap_size].
1038**
1039** <li>[[SQLITE_FCNTL_TRACE]]
1040** The [SQLITE_FCNTL_TRACE] file control provides advisory information
1041** to the VFS about what the higher layers of the SQLite stack are doing.
1042** This file control is used by some VFS activity tracing [shims].
1043** The argument is a zero-terminated string. Higher layers in the
1044** SQLite stack may generate instances of this file control if
1045** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
1046**
1047** <li>[[SQLITE_FCNTL_HAS_MOVED]]
1048** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
1049** pointer to an integer and it writes a boolean into that integer depending
1050** on whether or not the file has been renamed, moved, or deleted since it
1051** was first opened.
1052**
1053** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
1054** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
1055** underlying native file handle associated with a file handle. This file
1056** control interprets its argument as a pointer to a native file handle and
1057** writes the resulting value there.
1058**
1059** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
1060** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This
1061** opcode causes the xFileControl method to swap the file handle with the one
1062** pointed to by the pArg argument. This capability is used during testing
1063** and only needs to be supported when SQLITE_TEST is defined.
1064**
1065** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
1066** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
1067** be advantageous to block on the next WAL lock if the lock is not immediately
1068** available. The WAL subsystem issues this signal during rare
1069** circumstances in order to fix a problem with priority inversion.
1070** Applications should <em>not</em> use this file-control.
1071**
1072** <li>[[SQLITE_FCNTL_ZIPVFS]]
1073** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
1074** VFS should return SQLITE_NOTFOUND for this opcode.
1075**
1076** <li>[[SQLITE_FCNTL_RBU]]
1077** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
1078** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for
1079** this opcode.
1080**
1081** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
1082** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
1083** the file descriptor is placed in "batch write mode", which
1084** means all subsequent write operations will be deferred and done
1085** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems
1086** that do not support batch atomic writes will return SQLITE_NOTFOUND.
1087** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
1088** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
1089** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
1090** no VFS interface calls on the same [sqlite3_file] file descriptor
1091** except for calls to the xWrite method and the xFileControl method
1092** with [SQLITE_FCNTL_SIZE_HINT].
1093**
1094** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
1095** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
1096** operations since the previous successful call to
1097** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
1098** This file control returns [SQLITE_OK] if and only if the writes were
1099** all performed successfully and have been committed to persistent storage.
1100** ^Regardless of whether or not it is successful, this file control takes
1101** the file descriptor out of batch write mode so that all subsequent
1102** write operations are independent.
1103** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
1104** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1105**
1106** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
1107** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
1108** operations since the previous successful call to
1109** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
1110** ^This file control takes the file descriptor out of batch write mode
1111** so that all subsequent write operations are independent.
1112** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
1113** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1114**
1115** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]]
1116** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS
1117** to block for up to M milliseconds before failing when attempting to
1118** obtain a file lock using the xLock or xShmLock methods of the VFS.
1119** The parameter is a pointer to a 32-bit signed integer that contains
1120** the value that M is to be set to. Before returning, the 32-bit signed
1121** integer is overwritten with the previous value of M.
1122**
1123** <li>[[SQLITE_FCNTL_DATA_VERSION]]
1124** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
1125** a database file. The argument is a pointer to a 32-bit unsigned integer.
1126** The "data version" for the pager is written into the pointer. The
1127** "data version" changes whenever any change occurs to the corresponding
1128** database file, either through SQL statements on the same database
1129** connection or through transactions committed by separate database
1130** connections possibly in other processes. The [sqlite3_total_changes()]
1131** interface can be used to find if any database on the connection has changed,
1132** but that interface responds to changes on TEMP as well as MAIN and does
1133** not provide a mechanism to detect changes to MAIN only. Also, the
1134** [sqlite3_total_changes()] interface responds to internal changes only and
1135** omits changes made by other database connections. The
1136** [PRAGMA data_version] command provides a mechanism to detect changes to
1137** a single attached database that occur due to other database connections,
1138** but omits changes implemented by the database connection on which it is
1139** called. This file control is the only mechanism to detect changes that
1140** happen either internally or externally and that are associated with
1141** a particular attached database.
1142**
1143** <li>[[SQLITE_FCNTL_CKPT_START]]
1144** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint
1145** in wal mode before the client starts to copy pages from the wal
1146** file to the database file.
1147**
1148** <li>[[SQLITE_FCNTL_CKPT_DONE]]
1149** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint
1150** in wal mode after the client has finished copying pages from the wal
1151** file to the database file, but before the *-shm file is updated to
1152** record the fact that the pages have been checkpointed.
1153** </ul>
1154**
1155** <li>[[SQLITE_FCNTL_EXTERNAL_READER]]
1156** The EXPERIMENTAL [SQLITE_FCNTL_EXTERNAL_READER] opcode is used to detect
1157** whether or not there is a database client in another process with a wal-mode
1158** transaction open on the database or not. It is only available on unix.The
1159** (void*) argument passed with this file-control should be a pointer to a
1160** value of type (int). The integer value is set to 1 if the database is a wal
1161** mode database and there exists at least one client in another process that
1162** currently has an SQL transaction open on the database. It is set to 0 if
1163** the database is not a wal-mode db, or if there is no such connection in any
1164** other process. This opcode cannot be used to detect transactions opened
1165** by clients within the current process, only within other processes.
1166** </ul>
1167**
1168** <li>[[SQLITE_FCNTL_CKSM_FILE]]
1169** Used by the cksmvfs VFS module only.
1170** </ul>
1171*/
1172#define SQLITE_FCNTL_LOCKSTATE 1
1173#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2
1174#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3
1175#define SQLITE_FCNTL_LAST_ERRNO 4
1176#define SQLITE_FCNTL_SIZE_HINT 5
1177#define SQLITE_FCNTL_CHUNK_SIZE 6
1178#define SQLITE_FCNTL_FILE_POINTER 7
1179#define SQLITE_FCNTL_SYNC_OMITTED 8
1180#define SQLITE_FCNTL_WIN32_AV_RETRY 9
1181#define SQLITE_FCNTL_PERSIST_WAL 10
1182#define SQLITE_FCNTL_OVERWRITE 11
1183#define SQLITE_FCNTL_VFSNAME 12
1184#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
1185#define SQLITE_FCNTL_PRAGMA 14
1186#define SQLITE_FCNTL_BUSYHANDLER 15
1187#define SQLITE_FCNTL_TEMPFILENAME 16
1188#define SQLITE_FCNTL_MMAP_SIZE 18
1189#define SQLITE_FCNTL_TRACE 19
1190#define SQLITE_FCNTL_HAS_MOVED 20
1191#define SQLITE_FCNTL_SYNC 21
1192#define SQLITE_FCNTL_COMMIT_PHASETWO 22
1193#define SQLITE_FCNTL_WIN32_SET_HANDLE 23
1194#define SQLITE_FCNTL_WAL_BLOCK 24
1195#define SQLITE_FCNTL_ZIPVFS 25
1196#define SQLITE_FCNTL_RBU 26
1197#define SQLITE_FCNTL_VFS_POINTER 27
1198#define SQLITE_FCNTL_JOURNAL_POINTER 28
1199#define SQLITE_FCNTL_WIN32_GET_HANDLE 29
1200#define SQLITE_FCNTL_PDB 30
1201#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31
1202#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32
1203#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33
1204#define SQLITE_FCNTL_LOCK_TIMEOUT 34
1205#define SQLITE_FCNTL_DATA_VERSION 35
1206#define SQLITE_FCNTL_SIZE_LIMIT 36
1207#define SQLITE_FCNTL_CKPT_DONE 37
1208#define SQLITE_FCNTL_RESERVE_BYTES 38
1209#define SQLITE_FCNTL_CKPT_START 39
1210#define SQLITE_FCNTL_EXTERNAL_READER 40
1211#define SQLITE_FCNTL_CKSM_FILE 41
1212
1213/* deprecated names */
1214#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE
1215#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE
1216#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO
1217
1218
1219/*
1220** CAPI3REF: Mutex Handle
1221**
1222** The mutex module within SQLite defines [sqlite3_mutex] to be an
1223** abstract type for a mutex object. The SQLite core never looks
1224** at the internal representation of an [sqlite3_mutex]. It only
1225** deals with pointers to the [sqlite3_mutex] object.
1226**
1227** Mutexes are created using [sqlite3_mutex_alloc()].
1228*/
1229typedef struct sqlite3_mutex sqlite3_mutex;
1230
1231/*
1232** CAPI3REF: Loadable Extension Thunk
1233**
1234** A pointer to the opaque sqlite3_api_routines structure is passed as
1235** the third parameter to entry points of [loadable extensions]. This
1236** structure must be typedefed in order to work around compiler warnings
1237** on some platforms.
1238*/
1239typedef struct sqlite3_api_routines sqlite3_api_routines;
1240
1241/*
1242** CAPI3REF: OS Interface Object
1243**
1244** An instance of the sqlite3_vfs object defines the interface between
1245** the SQLite core and the underlying operating system. The "vfs"
1246** in the name of the object stands for "virtual file system". See
1247** the [VFS | VFS documentation] for further information.
1248**
1249** The VFS interface is sometimes extended by adding new methods onto
1250** the end. Each time such an extension occurs, the iVersion field
1251** is incremented. The iVersion value started out as 1 in
1252** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
1253** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
1254** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields
1255** may be appended to the sqlite3_vfs object and the iVersion value
1256** may increase again in future versions of SQLite.
1257** Note that due to an oversight, the structure
1258** of the sqlite3_vfs object changed in the transition from
1259** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
1260** and yet the iVersion field was not increased.
1261**
1262** The szOsFile field is the size of the subclassed [sqlite3_file]
1263** structure used by this VFS. mxPathname is the maximum length of
1264** a pathname in this VFS.
1265**
1266** Registered sqlite3_vfs objects are kept on a linked list formed by
1267** the pNext pointer. The [sqlite3_vfs_register()]
1268** and [sqlite3_vfs_unregister()] interfaces manage this list
1269** in a thread-safe way. The [sqlite3_vfs_find()] interface
1270** searches the list. Neither the application code nor the VFS
1271** implementation should use the pNext pointer.
1272**
1273** The pNext field is the only field in the sqlite3_vfs
1274** structure that SQLite will ever modify. SQLite will only access
1275** or modify this field while holding a particular static mutex.
1276** The application should never modify anything within the sqlite3_vfs
1277** object once the object has been registered.
1278**
1279** The zName field holds the name of the VFS module. The name must
1280** be unique across all VFS modules.
1281**
1282** [[sqlite3_vfs.xOpen]]
1283** ^SQLite guarantees that the zFilename parameter to xOpen
1284** is either a NULL pointer or string obtained
1285** from xFullPathname() with an optional suffix added.
1286** ^If a suffix is added to the zFilename parameter, it will
1287** consist of a single "-" character followed by no more than
1288** 11 alphanumeric and/or "-" characters.
1289** ^SQLite further guarantees that
1290** the string will be valid and unchanged until xClose() is
1291** called. Because of the previous sentence,
1292** the [sqlite3_file] can safely store a pointer to the
1293** filename if it needs to remember the filename for some reason.
1294** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1295** must invent its own temporary name for the file. ^Whenever the
1296** xFilename parameter is NULL it will also be the case that the
1297** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1298**
1299** The flags argument to xOpen() includes all bits set in
1300** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
1301** or [sqlite3_open16()] is used, then flags includes at least
1302** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1303** If xOpen() opens a file read-only then it sets *pOutFlags to
1304** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
1305**
1306** ^(SQLite will also add one of the following flags to the xOpen()
1307** call, depending on the object being opened:
1308**
1309** <ul>
1310** <li> [SQLITE_OPEN_MAIN_DB]
1311** <li> [SQLITE_OPEN_MAIN_JOURNAL]
1312** <li> [SQLITE_OPEN_TEMP_DB]
1313** <li> [SQLITE_OPEN_TEMP_JOURNAL]
1314** <li> [SQLITE_OPEN_TRANSIENT_DB]
1315** <li> [SQLITE_OPEN_SUBJOURNAL]
1316** <li> [SQLITE_OPEN_SUPER_JOURNAL]
1317** <li> [SQLITE_OPEN_WAL]
1318** </ul>)^
1319**
1320** The file I/O implementation can use the object type flags to
1321** change the way it deals with files. For example, an application
1322** that does not care about crash recovery or rollback might make
1323** the open of a journal file a no-op. Writes to this journal would
1324** also be no-ops, and any attempt to read the journal would return
1325** SQLITE_IOERR. Or the implementation might recognize that a database
1326** file will be doing page-aligned sector reads and writes in a random
1327** order and set up its I/O subsystem accordingly.
1328**
1329** SQLite might also add one of the following flags to the xOpen method:
1330**
1331** <ul>
1332** <li> [SQLITE_OPEN_DELETEONCLOSE]
1333** <li> [SQLITE_OPEN_EXCLUSIVE]
1334** </ul>
1335**
1336** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1337** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1338** will be set for TEMP databases and their journals, transient
1339** databases, and subjournals.
1340**
1341** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1342** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1343** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1344** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1345** SQLITE_OPEN_CREATE, is used to indicate that file should always
1346** be created, and that it is an error if it already exists.
1347** It is <i>not</i> used to indicate the file should be opened
1348** for exclusive access.
1349**
1350** ^At least szOsFile bytes of memory are allocated by SQLite
1351** to hold the [sqlite3_file] structure passed as the third
1352** argument to xOpen. The xOpen method does not have to
1353** allocate the structure; it should just fill it in. Note that
1354** the xOpen method must set the sqlite3_file.pMethods to either
1355** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1356** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1357** element will be valid after xOpen returns regardless of the success
1358** or failure of the xOpen call.
1359**
1360** [[sqlite3_vfs.xAccess]]
1361** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1362** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1363** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1364** to test whether a file is at least readable. The SQLITE_ACCESS_READ
1365** flag is never actually used and is not implemented in the built-in
1366** VFSes of SQLite. The file is named by the second argument and can be a
1367** directory. The xAccess method returns [SQLITE_OK] on success or some
1368** non-zero error code if there is an I/O error or if the name of
1369** the file given in the second argument is illegal. If SQLITE_OK
1370** is returned, then non-zero or zero is written into *pResOut to indicate
1371** whether or not the file is accessible.
1372**
1373** ^SQLite will always allocate at least mxPathname+1 bytes for the
1374** output buffer xFullPathname. The exact size of the output buffer
1375** is also passed as a parameter to both methods. If the output buffer
1376** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1377** handled as a fatal error by SQLite, vfs implementations should endeavor
1378** to prevent this by setting mxPathname to a sufficiently large value.
1379**
1380** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1381** interfaces are not strictly a part of the filesystem, but they are
1382** included in the VFS structure for completeness.
1383** The xRandomness() function attempts to return nBytes bytes
1384** of good-quality randomness into zOut. The return value is
1385** the actual number of bytes of randomness obtained.
1386** The xSleep() method causes the calling thread to sleep for at
1387** least the number of microseconds given. ^The xCurrentTime()
1388** method returns a Julian Day Number for the current date and time as
1389** a floating point value.
1390** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1391** Day Number multiplied by 86400000 (the number of milliseconds in
1392** a 24-hour day).
1393** ^SQLite will use the xCurrentTimeInt64() method to get the current
1394** date and time if that method is available (if iVersion is 2 or
1395** greater and the function pointer is not NULL) and will fall back
1396** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1397**
1398** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1399** are not used by the SQLite core. These optional interfaces are provided
1400** by some VFSes to facilitate testing of the VFS code. By overriding
1401** system calls with functions under its control, a test program can
1402** simulate faults and error conditions that would otherwise be difficult
1403** or impossible to induce. The set of system calls that can be overridden
1404** varies from one VFS to another, and from one version of the same VFS to the
1405** next. Applications that use these interfaces must be prepared for any
1406** or all of these interfaces to be NULL or for their behavior to change
1407** from one release to the next. Applications must not attempt to access
1408** any of these methods if the iVersion of the VFS is less than 3.
1409*/
1410typedef struct sqlite3_vfs sqlite3_vfs;
1411typedef void (*sqlite3_syscall_ptr)(void);
1412struct sqlite3_vfs {
1413 int iVersion; /* Structure version number (currently 3) */
1414 int szOsFile; /* Size of subclassed sqlite3_file */
1415 int mxPathname; /* Maximum file pathname length */
1416 sqlite3_vfs *pNext; /* Next registered VFS */
1417 const char *zName; /* Name of this virtual file system */
1418 void *pAppData; /* Pointer to application-specific data */
1419 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1420 int flags, int *pOutFlags);
1421 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1422 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1423 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1424 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1425 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1426 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1427 void (*xDlClose)(sqlite3_vfs*, void*);
1428 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1429 int (*xSleep)(sqlite3_vfs*, int microseconds);
1430 int (*xCurrentTime)(sqlite3_vfs*, double*);
1431 int (*xGetLastError)(sqlite3_vfs*, int, char *);
1432 /*
1433 ** The methods above are in version 1 of the sqlite_vfs object
1434 ** definition. Those that follow are added in version 2 or later
1435 */
1436 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1437 /*
1438 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1439 ** Those below are for version 3 and greater.
1440 */
1441 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1442 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1443 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1444 /*
1445 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1446 ** New fields may be appended in future versions. The iVersion
1447 ** value will increment whenever this happens.
1448 */
1449};
1450
1451/*
1452** CAPI3REF: Flags for the xAccess VFS method
1453**
1454** These integer constants can be used as the third parameter to
1455** the xAccess method of an [sqlite3_vfs] object. They determine
1456** what kind of permissions the xAccess method is looking for.
1457** With SQLITE_ACCESS_EXISTS, the xAccess method
1458** simply checks whether the file exists.
1459** With SQLITE_ACCESS_READWRITE, the xAccess method
1460** checks whether the named directory is both readable and writable
1461** (in other words, if files can be added, removed, and renamed within
1462** the directory).
1463** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1464** [temp_store_directory pragma], though this could change in a future
1465** release of SQLite.
1466** With SQLITE_ACCESS_READ, the xAccess method
1467** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1468** currently unused, though it might be used in a future release of
1469** SQLite.
1470*/
1471#define SQLITE_ACCESS_EXISTS 0
1472#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1473#define SQLITE_ACCESS_READ 2 /* Unused */
1474
1475/*
1476** CAPI3REF: Flags for the xShmLock VFS method
1477**
1478** These integer constants define the various locking operations
1479** allowed by the xShmLock method of [sqlite3_io_methods]. The
1480** following are the only legal combinations of flags to the
1481** xShmLock method:
1482**
1483** <ul>
1484** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1485** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1486** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1487** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1488** </ul>
1489**
1490** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1491** was given on the corresponding lock.
1492**
1493** The xShmLock method can transition between unlocked and SHARED or
1494** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1495** and EXCLUSIVE.
1496*/
1497#define SQLITE_SHM_UNLOCK 1
1498#define SQLITE_SHM_LOCK 2
1499#define SQLITE_SHM_SHARED 4
1500#define SQLITE_SHM_EXCLUSIVE 8
1501
1502/*
1503** CAPI3REF: Maximum xShmLock index
1504**
1505** The xShmLock method on [sqlite3_io_methods] may use values
1506** between 0 and this upper bound as its "offset" argument.
1507** The SQLite core will never attempt to acquire or release a
1508** lock outside of this range
1509*/
1510#define SQLITE_SHM_NLOCK 8
1511
1512
1513/*
1514** CAPI3REF: Initialize The SQLite Library
1515**
1516** ^The sqlite3_initialize() routine initializes the
1517** SQLite library. ^The sqlite3_shutdown() routine
1518** deallocates any resources that were allocated by sqlite3_initialize().
1519** These routines are designed to aid in process initialization and
1520** shutdown on embedded systems. Workstation applications using
1521** SQLite normally do not need to invoke either of these routines.
1522**
1523** A call to sqlite3_initialize() is an "effective" call if it is
1524** the first time sqlite3_initialize() is invoked during the lifetime of
1525** the process, or if it is the first time sqlite3_initialize() is invoked
1526** following a call to sqlite3_shutdown(). ^(Only an effective call
1527** of sqlite3_initialize() does any initialization. All other calls
1528** are harmless no-ops.)^
1529**
1530** A call to sqlite3_shutdown() is an "effective" call if it is the first
1531** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1532** an effective call to sqlite3_shutdown() does any deinitialization.
1533** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1534**
1535** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1536** is not. The sqlite3_shutdown() interface must only be called from a
1537** single thread. All open [database connections] must be closed and all
1538** other SQLite resources must be deallocated prior to invoking
1539** sqlite3_shutdown().
1540**
1541** Among other things, ^sqlite3_initialize() will invoke
1542** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1543** will invoke sqlite3_os_end().
1544**
1545** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1546** ^If for some reason, sqlite3_initialize() is unable to initialize
1547** the library (perhaps it is unable to allocate a needed resource such
1548** as a mutex) it returns an [error code] other than [SQLITE_OK].
1549**
1550** ^The sqlite3_initialize() routine is called internally by many other
1551** SQLite interfaces so that an application usually does not need to
1552** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1553** calls sqlite3_initialize() so the SQLite library will be automatically
1554** initialized when [sqlite3_open()] is called if it has not be initialized
1555** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1556** compile-time option, then the automatic calls to sqlite3_initialize()
1557** are omitted and the application must call sqlite3_initialize() directly
1558** prior to using any other SQLite interface. For maximum portability,
1559** it is recommended that applications always invoke sqlite3_initialize()
1560** directly prior to using any other SQLite interface. Future releases
1561** of SQLite may require this. In other words, the behavior exhibited
1562** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1563** default behavior in some future release of SQLite.
1564**
1565** The sqlite3_os_init() routine does operating-system specific
1566** initialization of the SQLite library. The sqlite3_os_end()
1567** routine undoes the effect of sqlite3_os_init(). Typical tasks
1568** performed by these routines include allocation or deallocation
1569** of static resources, initialization of global variables,
1570** setting up a default [sqlite3_vfs] module, or setting up
1571** a default configuration using [sqlite3_config()].
1572**
1573** The application should never invoke either sqlite3_os_init()
1574** or sqlite3_os_end() directly. The application should only invoke
1575** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1576** interface is called automatically by sqlite3_initialize() and
1577** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1578** implementations for sqlite3_os_init() and sqlite3_os_end()
1579** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1580** When [custom builds | built for other platforms]
1581** (using the [SQLITE_OS_OTHER=1] compile-time
1582** option) the application must supply a suitable implementation for
1583** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1584** implementation of sqlite3_os_init() or sqlite3_os_end()
1585** must return [SQLITE_OK] on success and some other [error code] upon
1586** failure.
1587*/
1588
1589/*
1590** CAPI3REF: Configuring The SQLite Library
1591**
1592** The sqlite3_config() interface is used to make global configuration
1593** changes to SQLite in order to tune SQLite to the specific needs of
1594** the application. The default configuration is recommended for most
1595** applications and so this routine is usually not necessary. It is
1596** provided to support rare applications with unusual needs.
1597**
1598** <b>The sqlite3_config() interface is not threadsafe. The application
1599** must ensure that no other SQLite interfaces are invoked by other
1600** threads while sqlite3_config() is running.</b>
1601**
1602** The sqlite3_config() interface
1603** may only be invoked prior to library initialization using
1604** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1605** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1606** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1607** Note, however, that ^sqlite3_config() can be called as part of the
1608** implementation of an application-defined [sqlite3_os_init()].
1609**
1610** The first argument to sqlite3_config() is an integer
1611** [configuration option] that determines
1612** what property of SQLite is to be configured. Subsequent arguments
1613** vary depending on the [configuration option]
1614** in the first argument.
1615**
1616** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1617** ^If the option is unknown or SQLite is unable to set the option
1618** then this routine returns a non-zero [error code].
1619*/
1620
1621/*
1622** CAPI3REF: Configure database connections
1623** METHOD: sqlite3
1624**
1625** The sqlite3_db_config() interface is used to make configuration
1626** changes to a [database connection]. The interface is similar to
1627** [sqlite3_config()] except that the changes apply to a single
1628** [database connection] (specified in the first argument).
1629**
1630** The second argument to sqlite3_db_config(D,V,...) is the
1631** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1632** that indicates what aspect of the [database connection] is being configured.
1633** Subsequent arguments vary depending on the configuration verb.
1634**
1635** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1636** the call is considered successful.
1637*/
1638
1639/*
1640** CAPI3REF: Memory Allocation Routines
1641**
1642** An instance of this object defines the interface between SQLite
1643** and low-level memory allocation routines.
1644**
1645** This object is used in only one place in the SQLite interface.
1646** A pointer to an instance of this object is the argument to
1647** [sqlite3_config()] when the configuration option is
1648** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1649** By creating an instance of this object
1650** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1651** during configuration, an application can specify an alternative
1652** memory allocation subsystem for SQLite to use for all of its
1653** dynamic memory needs.
1654**
1655** Note that SQLite comes with several [built-in memory allocators]
1656** that are perfectly adequate for the overwhelming majority of applications
1657** and that this object is only useful to a tiny minority of applications
1658** with specialized memory allocation requirements. This object is
1659** also used during testing of SQLite in order to specify an alternative
1660** memory allocator that simulates memory out-of-memory conditions in
1661** order to verify that SQLite recovers gracefully from such
1662** conditions.
1663**
1664** The xMalloc, xRealloc, and xFree methods must work like the
1665** malloc(), realloc() and free() functions from the standard C library.
1666** ^SQLite guarantees that the second argument to
1667** xRealloc is always a value returned by a prior call to xRoundup.
1668**
1669** xSize should return the allocated size of a memory allocation
1670** previously obtained from xMalloc or xRealloc. The allocated size
1671** is always at least as big as the requested size but may be larger.
1672**
1673** The xRoundup method returns what would be the allocated size of
1674** a memory allocation given a particular requested size. Most memory
1675** allocators round up memory allocations at least to the next multiple
1676** of 8. Some allocators round up to a larger multiple or to a power of 2.
1677** Every memory allocation request coming in through [sqlite3_malloc()]
1678** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1679** that causes the corresponding memory allocation to fail.
1680**
1681** The xInit method initializes the memory allocator. For example,
1682** it might allocate any required mutexes or initialize internal data
1683** structures. The xShutdown method is invoked (indirectly) by
1684** [sqlite3_shutdown()] and should deallocate any resources acquired
1685** by xInit. The pAppData pointer is used as the only parameter to
1686** xInit and xShutdown.
1687**
1688** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes
1689** the xInit method, so the xInit method need not be threadsafe. The
1690** xShutdown method is only called from [sqlite3_shutdown()] so it does
1691** not need to be threadsafe either. For all other methods, SQLite
1692** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1693** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1694** it is by default) and so the methods are automatically serialized.
1695** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1696** methods must be threadsafe or else make their own arrangements for
1697** serialization.
1698**
1699** SQLite will never invoke xInit() more than once without an intervening
1700** call to xShutdown().
1701*/
1702typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1703struct sqlite3_mem_methods {
1704 void *(*xMalloc)(int); /* Memory allocation function */
1705 void (*xFree)(void*); /* Free a prior allocation */
1706 void *(*xRealloc)(void*,int); /* Resize an allocation */
1707 int (*xSize)(void*); /* Return the size of an allocation */
1708 int (*xRoundup)(int); /* Round up request size to allocation size */
1709 int (*xInit)(void*); /* Initialize the memory allocator */
1710 void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1711 void *pAppData; /* Argument to xInit() and xShutdown() */
1712};
1713
1714/*
1715** CAPI3REF: Configuration Options
1716** KEYWORDS: {configuration option}
1717**
1718** These constants are the available integer configuration options that
1719** can be passed as the first argument to the [sqlite3_config()] interface.
1720**
1721** New configuration options may be added in future releases of SQLite.
1722** Existing configuration options might be discontinued. Applications
1723** should check the return code from [sqlite3_config()] to make sure that
1724** the call worked. The [sqlite3_config()] interface will return a
1725** non-zero [error code] if a discontinued or unsupported configuration option
1726** is invoked.
1727**
1728** <dl>
1729** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1730** <dd>There are no arguments to this option. ^This option sets the
1731** [threading mode] to Single-thread. In other words, it disables
1732** all mutexing and puts SQLite into a mode where it can only be used
1733** by a single thread. ^If SQLite is compiled with
1734** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1735** it is not possible to change the [threading mode] from its default
1736** value of Single-thread and so [sqlite3_config()] will return
1737** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1738** configuration option.</dd>
1739**
1740** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1741** <dd>There are no arguments to this option. ^This option sets the
1742** [threading mode] to Multi-thread. In other words, it disables
1743** mutexing on [database connection] and [prepared statement] objects.
1744** The application is responsible for serializing access to
1745** [database connections] and [prepared statements]. But other mutexes
1746** are enabled so that SQLite will be safe to use in a multi-threaded
1747** environment as long as no two threads attempt to use the same
1748** [database connection] at the same time. ^If SQLite is compiled with
1749** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1750** it is not possible to set the Multi-thread [threading mode] and
1751** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1752** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1753**
1754** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1755** <dd>There are no arguments to this option. ^This option sets the
1756** [threading mode] to Serialized. In other words, this option enables
1757** all mutexes including the recursive
1758** mutexes on [database connection] and [prepared statement] objects.
1759** In this mode (which is the default when SQLite is compiled with
1760** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1761** to [database connections] and [prepared statements] so that the
1762** application is free to use the same [database connection] or the
1763** same [prepared statement] in different threads at the same time.
1764** ^If SQLite is compiled with
1765** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1766** it is not possible to set the Serialized [threading mode] and
1767** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1768** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1769**
1770** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1771** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1772** a pointer to an instance of the [sqlite3_mem_methods] structure.
1773** The argument specifies
1774** alternative low-level memory allocation routines to be used in place of
1775** the memory allocation routines built into SQLite.)^ ^SQLite makes
1776** its own private copy of the content of the [sqlite3_mem_methods] structure
1777** before the [sqlite3_config()] call returns.</dd>
1778**
1779** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1780** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1781** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1782** The [sqlite3_mem_methods]
1783** structure is filled with the currently defined memory allocation routines.)^
1784** This option can be used to overload the default memory allocation
1785** routines with a wrapper that simulations memory allocation failure or
1786** tracks memory usage, for example. </dd>
1787**
1788** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
1789** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
1790** type int, interpreted as a boolean, which if true provides a hint to
1791** SQLite that it should avoid large memory allocations if possible.
1792** SQLite will run faster if it is free to make large memory allocations,
1793** but some application might prefer to run slower in exchange for
1794** guarantees about memory fragmentation that are possible if large
1795** allocations are avoided. This hint is normally off.
1796** </dd>
1797**
1798** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1799** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1800** interpreted as a boolean, which enables or disables the collection of
1801** memory allocation statistics. ^(When memory allocation statistics are
1802** disabled, the following SQLite interfaces become non-operational:
1803** <ul>
1804** <li> [sqlite3_hard_heap_limit64()]
1805** <li> [sqlite3_memory_used()]
1806** <li> [sqlite3_memory_highwater()]
1807** <li> [sqlite3_soft_heap_limit64()]
1808** <li> [sqlite3_status64()]
1809** </ul>)^
1810** ^Memory allocation statistics are enabled by default unless SQLite is
1811** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1812** allocation statistics are disabled by default.
1813** </dd>
1814**
1815** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1816** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
1817** </dd>
1818**
1819** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1820** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
1821** that SQLite can use for the database page cache with the default page
1822** cache implementation.
1823** This configuration option is a no-op if an application-defined page
1824** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
1825** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1826** 8-byte aligned memory (pMem), the size of each page cache line (sz),
1827** and the number of cache lines (N).
1828** The sz argument should be the size of the largest database page
1829** (a power of two between 512 and 65536) plus some extra bytes for each
1830** page header. ^The number of extra bytes needed by the page header
1831** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
1832** ^It is harmless, apart from the wasted memory,
1833** for the sz parameter to be larger than necessary. The pMem
1834** argument must be either a NULL pointer or a pointer to an 8-byte
1835** aligned block of memory of at least sz*N bytes, otherwise
1836** subsequent behavior is undefined.
1837** ^When pMem is not NULL, SQLite will strive to use the memory provided
1838** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
1839** a page cache line is larger than sz bytes or if all of the pMem buffer
1840** is exhausted.
1841** ^If pMem is NULL and N is non-zero, then each database connection
1842** does an initial bulk allocation for page cache memory
1843** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
1844** of -1024*N bytes if N is negative, . ^If additional
1845** page cache memory is needed beyond what is provided by the initial
1846** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
1847** additional cache line. </dd>
1848**
1849** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1850** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1851** that SQLite will use for all of its dynamic memory allocation needs
1852** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
1853** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1854** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1855** [SQLITE_ERROR] if invoked otherwise.
1856** ^There are three arguments to SQLITE_CONFIG_HEAP:
1857** An 8-byte aligned pointer to the memory,
1858** the number of bytes in the memory buffer, and the minimum allocation size.
1859** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1860** to using its default memory allocator (the system malloc() implementation),
1861** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1862** memory pointer is not NULL then the alternative memory
1863** allocator is engaged to handle all of SQLites memory allocation needs.
1864** The first pointer (the memory pointer) must be aligned to an 8-byte
1865** boundary or subsequent behavior of SQLite will be undefined.
1866** The minimum allocation size is capped at 2**12. Reasonable values
1867** for the minimum allocation size are 2**5 through 2**8.</dd>
1868**
1869** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1870** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1871** pointer to an instance of the [sqlite3_mutex_methods] structure.
1872** The argument specifies alternative low-level mutex routines to be used
1873** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of
1874** the content of the [sqlite3_mutex_methods] structure before the call to
1875** [sqlite3_config()] returns. ^If SQLite is compiled with
1876** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1877** the entire mutexing subsystem is omitted from the build and hence calls to
1878** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1879** return [SQLITE_ERROR].</dd>
1880**
1881** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1882** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1883** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The
1884** [sqlite3_mutex_methods]
1885** structure is filled with the currently defined mutex routines.)^
1886** This option can be used to overload the default mutex allocation
1887** routines with a wrapper used to track mutex usage for performance
1888** profiling or testing, for example. ^If SQLite is compiled with
1889** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1890** the entire mutexing subsystem is omitted from the build and hence calls to
1891** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1892** return [SQLITE_ERROR].</dd>
1893**
1894** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1895** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1896** the default size of lookaside memory on each [database connection].
1897** The first argument is the
1898** size of each lookaside buffer slot and the second is the number of
1899** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE
1900** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1901** option to [sqlite3_db_config()] can be used to change the lookaside
1902** configuration on individual connections.)^ </dd>
1903**
1904** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1905** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1906** a pointer to an [sqlite3_pcache_methods2] object. This object specifies
1907** the interface to a custom page cache implementation.)^
1908** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1909**
1910** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1911** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1912** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of
1913** the current page cache implementation into that object.)^ </dd>
1914**
1915** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1916** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1917** global [error log].
1918** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1919** function with a call signature of void(*)(void*,int,const char*),
1920** and a pointer to void. ^If the function pointer is not NULL, it is
1921** invoked by [sqlite3_log()] to process each logging event. ^If the
1922** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1923** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1924** passed through as the first parameter to the application-defined logger
1925** function whenever that function is invoked. ^The second parameter to
1926** the logger function is a copy of the first parameter to the corresponding
1927** [sqlite3_log()] call and is intended to be a [result code] or an
1928** [extended result code]. ^The third parameter passed to the logger is
1929** log message after formatting via [sqlite3_snprintf()].
1930** The SQLite logging interface is not reentrant; the logger function
1931** supplied by the application must not invoke any SQLite interface.
1932** In a multi-threaded application, the application-defined logger
1933** function must be threadsafe. </dd>
1934**
1935** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1936** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1937** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1938** then URI handling is globally disabled.)^ ^If URI handling is globally
1939** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1940** [sqlite3_open16()] or
1941** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1942** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1943** connection is opened. ^If it is globally disabled, filenames are
1944** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1945** database connection is opened. ^(By default, URI handling is globally
1946** disabled. The default value may be changed by compiling with the
1947** [SQLITE_USE_URI] symbol defined.)^
1948**
1949** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1950** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1951** argument which is interpreted as a boolean in order to enable or disable
1952** the use of covering indices for full table scans in the query optimizer.
1953** ^The default setting is determined
1954** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1955** if that compile-time option is omitted.
1956** The ability to disable the use of covering indices for full table scans
1957** is because some incorrectly coded legacy applications might malfunction
1958** when the optimization is enabled. Providing the ability to
1959** disable the optimization allows the older, buggy application code to work
1960** without change even with newer versions of SQLite.
1961**
1962** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1963** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1964** <dd> These options are obsolete and should not be used by new code.
1965** They are retained for backwards compatibility but are now no-ops.
1966** </dd>
1967**
1968** [[SQLITE_CONFIG_SQLLOG]]
1969** <dt>SQLITE_CONFIG_SQLLOG
1970** <dd>This option is only available if sqlite is compiled with the
1971** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1972** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1973** The second should be of type (void*). The callback is invoked by the library
1974** in three separate circumstances, identified by the value passed as the
1975** fourth parameter. If the fourth parameter is 0, then the database connection
1976** passed as the second argument has just been opened. The third argument
1977** points to a buffer containing the name of the main database file. If the
1978** fourth parameter is 1, then the SQL statement that the third parameter
1979** points to has just been executed. Or, if the fourth parameter is 2, then
1980** the connection being passed as the second parameter is being closed. The
1981** third parameter is passed NULL In this case. An example of using this
1982** configuration option can be seen in the "test_sqllog.c" source file in
1983** the canonical SQLite source tree.</dd>
1984**
1985** [[SQLITE_CONFIG_MMAP_SIZE]]
1986** <dt>SQLITE_CONFIG_MMAP_SIZE
1987** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1988** that are the default mmap size limit (the default setting for
1989** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1990** ^The default setting can be overridden by each database connection using
1991** either the [PRAGMA mmap_size] command, or by using the
1992** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size
1993** will be silently truncated if necessary so that it does not exceed the
1994** compile-time maximum mmap size set by the
1995** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1996** ^If either argument to this option is negative, then that argument is
1997** changed to its compile-time default.
1998**
1999** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
2000** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
2001** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
2002** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
2003** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
2004** that specifies the maximum size of the created heap.
2005**
2006** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
2007** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
2008** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
2009** is a pointer to an integer and writes into that integer the number of extra
2010** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
2011** The amount of extra space required can change depending on the compiler,
2012** target platform, and SQLite version.
2013**
2014** [[SQLITE_CONFIG_PMASZ]]
2015** <dt>SQLITE_CONFIG_PMASZ
2016** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
2017** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
2018** sorter to that integer. The default minimum PMA Size is set by the
2019** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched
2020** to help with sort operations when multithreaded sorting
2021** is enabled (using the [PRAGMA threads] command) and the amount of content
2022** to be sorted exceeds the page size times the minimum of the
2023** [PRAGMA cache_size] setting and this value.
2024**
2025** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
2026** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
2027** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
2028** becomes the [statement journal] spill-to-disk threshold.
2029** [Statement journals] are held in memory until their size (in bytes)
2030** exceeds this threshold, at which point they are written to disk.
2031** Or if the threshold is -1, statement journals are always held
2032** exclusively in memory.
2033** Since many statement journals never become large, setting the spill
2034** threshold to a value such as 64KiB can greatly reduce the amount of
2035** I/O required to support statement rollback.
2036** The default value for this setting is controlled by the
2037** [SQLITE_STMTJRNL_SPILL] compile-time option.
2038**
2039** [[SQLITE_CONFIG_SORTERREF_SIZE]]
2040** <dt>SQLITE_CONFIG_SORTERREF_SIZE
2041** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
2042** of type (int) - the new value of the sorter-reference size threshold.
2043** Usually, when SQLite uses an external sort to order records according
2044** to an ORDER BY clause, all fields required by the caller are present in the
2045** sorted records. However, if SQLite determines based on the declared type
2046** of a table column that its values are likely to be very large - larger
2047** than the configured sorter-reference size threshold - then a reference
2048** is stored in each sorted record and the required column values loaded
2049** from the database as records are returned in sorted order. The default
2050** value for this option is to never use this optimization. Specifying a
2051** negative value for this option restores the default behaviour.
2052** This option is only available if SQLite is compiled with the
2053** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
2054**
2055** [[SQLITE_CONFIG_MEMDB_MAXSIZE]]
2056** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE
2057** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
2058** [sqlite3_int64] parameter which is the default maximum size for an in-memory
2059** database created using [sqlite3_deserialize()]. This default maximum
2060** size can be adjusted up or down for individual databases using the
2061** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control]. If this
2062** configuration setting is never used, then the default maximum is determined
2063** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option. If that
2064** compile-time option is not set, then the default maximum is 1073741824.
2065** </dl>
2066*/
2067#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
2068#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
2069#define SQLITE_CONFIG_SERIALIZED 3 /* nil */
2070#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
2071#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
2072#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */
2073#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
2074#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
2075#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
2076#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
2077#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
2078/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
2079#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
2080#define SQLITE_CONFIG_PCACHE 14 /* no-op */
2081#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
2082#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
2083#define SQLITE_CONFIG_URI 17 /* int */
2084#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
2085#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
2086#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
2087#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
2088#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
2089#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
2090#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */
2091#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */
2092#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */
2093#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */
2094#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */
2095#define SQLITE_CONFIG_MEMDB_MAXSIZE 29 /* sqlite3_int64 */
2096
2097/*
2098** CAPI3REF: Database Connection Configuration Options
2099**
2100** These constants are the available integer configuration options that
2101** can be passed as the second argument to the [sqlite3_db_config()] interface.
2102**
2103** New configuration options may be added in future releases of SQLite.
2104** Existing configuration options might be discontinued. Applications
2105** should check the return code from [sqlite3_db_config()] to make sure that
2106** the call worked. ^The [sqlite3_db_config()] interface will return a
2107** non-zero [error code] if a discontinued or unsupported configuration option
2108** is invoked.
2109**
2110** <dl>
2111** [[SQLITE_DBCONFIG_LOOKASIDE]]
2112** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
2113** <dd> ^This option takes three additional arguments that determine the
2114** [lookaside memory allocator] configuration for the [database connection].
2115** ^The first argument (the third parameter to [sqlite3_db_config()] is a
2116** pointer to a memory buffer to use for lookaside memory.
2117** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
2118** may be NULL in which case SQLite will allocate the
2119** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
2120** size of each lookaside buffer slot. ^The third argument is the number of
2121** slots. The size of the buffer in the first argument must be greater than
2122** or equal to the product of the second and third arguments. The buffer
2123** must be aligned to an 8-byte boundary. ^If the second argument to
2124** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
2125** rounded down to the next smaller multiple of 8. ^(The lookaside memory
2126** configuration for a database connection can only be changed when that
2127** connection is not currently using lookaside memory, or in other words
2128** when the "current value" returned by
2129** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
2130** Any attempt to change the lookaside memory configuration when lookaside
2131** memory is in use leaves the configuration unchanged and returns
2132** [SQLITE_BUSY].)^</dd>
2133**
2134** [[SQLITE_DBCONFIG_ENABLE_FKEY]]
2135** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
2136** <dd> ^This option is used to enable or disable the enforcement of
2137** [foreign key constraints]. There should be two additional arguments.
2138** The first argument is an integer which is 0 to disable FK enforcement,
2139** positive to enable FK enforcement or negative to leave FK enforcement
2140** unchanged. The second parameter is a pointer to an integer into which
2141** is written 0 or 1 to indicate whether FK enforcement is off or on
2142** following this call. The second parameter may be a NULL pointer, in
2143** which case the FK enforcement setting is not reported back. </dd>
2144**
2145** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]]
2146** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
2147** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
2148** There should be two additional arguments.
2149** The first argument is an integer which is 0 to disable triggers,
2150** positive to enable triggers or negative to leave the setting unchanged.
2151** The second parameter is a pointer to an integer into which
2152** is written 0 or 1 to indicate whether triggers are disabled or enabled
2153** following this call. The second parameter may be a NULL pointer, in
2154** which case the trigger setting is not reported back.
2155**
2156** <p>Originally this option disabled all triggers. ^(However, since
2157** SQLite version 3.35.0, TEMP triggers are still allowed even if
2158** this option is off. So, in other words, this option now only disables
2159** triggers in the main database schema or in the schemas of ATTACH-ed
2160** databases.)^ </dd>
2161**
2162** [[SQLITE_DBCONFIG_ENABLE_VIEW]]
2163** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt>
2164** <dd> ^This option is used to enable or disable [CREATE VIEW | views].
2165** There should be two additional arguments.
2166** The first argument is an integer which is 0 to disable views,
2167** positive to enable views or negative to leave the setting unchanged.
2168** The second parameter is a pointer to an integer into which
2169** is written 0 or 1 to indicate whether views are disabled or enabled
2170** following this call. The second parameter may be a NULL pointer, in
2171** which case the view setting is not reported back.
2172**
2173** <p>Originally this option disabled all views. ^(However, since
2174** SQLite version 3.35.0, TEMP views are still allowed even if
2175** this option is off. So, in other words, this option now only disables
2176** views in the main database schema or in the schemas of ATTACH-ed
2177** databases.)^ </dd>
2178**
2179** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]]
2180** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
2181** <dd> ^This option is used to enable or disable the
2182** [fts3_tokenizer()] function which is part of the
2183** [FTS3] full-text search engine extension.
2184** There should be two additional arguments.
2185** The first argument is an integer which is 0 to disable fts3_tokenizer() or
2186** positive to enable fts3_tokenizer() or negative to leave the setting
2187** unchanged.
2188** The second parameter is a pointer to an integer into which
2189** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
2190** following this call. The second parameter may be a NULL pointer, in
2191** which case the new setting is not reported back. </dd>
2192**
2193** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]]
2194** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
2195** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
2196** interface independently of the [load_extension()] SQL function.
2197** The [sqlite3_enable_load_extension()] API enables or disables both the
2198** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
2199** There should be two additional arguments.
2200** When the first argument to this interface is 1, then only the C-API is
2201** enabled and the SQL function remains disabled. If the first argument to
2202** this interface is 0, then both the C-API and the SQL function are disabled.
2203** If the first argument is -1, then no changes are made to state of either the
2204** C-API or the SQL function.
2205** The second parameter is a pointer to an integer into which
2206** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
2207** is disabled or enabled following this call. The second parameter may
2208** be a NULL pointer, in which case the new setting is not reported back.
2209** </dd>
2210**
2211** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
2212** <dd> ^This option is used to change the name of the "main" database
2213** schema. ^The sole argument is a pointer to a constant UTF8 string
2214** which will become the new schema name in place of "main". ^SQLite
2215** does not make a copy of the new main schema name string, so the application
2216** must ensure that the argument passed into this DBCONFIG option is unchanged
2217** until after the database connection closes.
2218** </dd>
2219**
2220** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]]
2221** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
2222** <dd> Usually, when a database in wal mode is closed or detached from a
2223** database handle, SQLite checks if this will mean that there are now no
2224** connections at all to the database. If so, it performs a checkpoint
2225** operation before closing the connection. This option may be used to
2226** override this behaviour. The first parameter passed to this operation
2227** is an integer - positive to disable checkpoints-on-close, or zero (the
2228** default) to enable them, and negative to leave the setting unchanged.
2229** The second parameter is a pointer to an integer
2230** into which is written 0 or 1 to indicate whether checkpoints-on-close
2231** have been disabled - 0 if they are not disabled, 1 if they are.
2232** </dd>
2233**
2234** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
2235** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
2236** the [query planner stability guarantee] (QPSG). When the QPSG is active,
2237** a single SQL query statement will always use the same algorithm regardless
2238** of values of [bound parameters].)^ The QPSG disables some query optimizations
2239** that look at the values of bound parameters, which can make some queries
2240** slower. But the QPSG has the advantage of more predictable behavior. With
2241** the QPSG active, SQLite will always use the same query plan in the field as
2242** was used during testing in the lab.
2243** The first argument to this setting is an integer which is 0 to disable
2244** the QPSG, positive to enable QPSG, or negative to leave the setting
2245** unchanged. The second parameter is a pointer to an integer into which
2246** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
2247** following this call.
2248** </dd>
2249**
2250** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
2251** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
2252** include output for any operations performed by trigger programs. This
2253** option is used to set or clear (the default) a flag that governs this
2254** behavior. The first parameter passed to this operation is an integer -
2255** positive to enable output for trigger programs, or zero to disable it,
2256** or negative to leave the setting unchanged.
2257** The second parameter is a pointer to an integer into which is written
2258** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
2259** it is not disabled, 1 if it is.
2260** </dd>
2261**
2262** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
2263** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
2264** [VACUUM] in order to reset a database back to an empty database
2265** with no schema and no content. The following process works even for
2266** a badly corrupted database file:
2267** <ol>
2268** <li> If the database connection is newly opened, make sure it has read the
2269** database schema by preparing then discarding some query against the
2270** database, or calling sqlite3_table_column_metadata(), ignoring any
2271** errors. This step is only necessary if the application desires to keep
2272** the database in WAL mode after the reset if it was in WAL mode before
2273** the reset.
2274** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
2275** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
2276** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
2277** </ol>
2278** Because resetting a database is destructive and irreversible, the
2279** process requires the use of this obscure API and multiple steps to help
2280** ensure that it does not happen by accident.
2281**
2282** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
2283** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
2284** "defensive" flag for a database connection. When the defensive
2285** flag is enabled, language features that allow ordinary SQL to
2286** deliberately corrupt the database file are disabled. The disabled
2287** features include but are not limited to the following:
2288** <ul>
2289** <li> The [PRAGMA writable_schema=ON] statement.
2290** <li> The [PRAGMA journal_mode=OFF] statement.
2291** <li> Writes to the [sqlite_dbpage] virtual table.
2292** <li> Direct writes to [shadow tables].
2293** </ul>
2294** </dd>
2295**
2296** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt>
2297** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
2298** "writable_schema" flag. This has the same effect and is logically equivalent
2299** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF].
2300** The first argument to this setting is an integer which is 0 to disable
2301** the writable_schema, positive to enable writable_schema, or negative to
2302** leave the setting unchanged. The second parameter is a pointer to an
2303** integer into which is written 0 or 1 to indicate whether the writable_schema
2304** is enabled or disabled following this call.
2305** </dd>
2306**
2307** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]]
2308** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt>
2309** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates
2310** the legacy behavior of the [ALTER TABLE RENAME] command such it
2311** behaves as it did prior to [version 3.24.0] (2018-06-04). See the
2312** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for
2313** additional information. This feature can also be turned on and off
2314** using the [PRAGMA legacy_alter_table] statement.
2315** </dd>
2316**
2317** [[SQLITE_DBCONFIG_DQS_DML]]
2318** <dt>SQLITE_DBCONFIG_DQS_DML</td>
2319** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates
2320** the legacy [double-quoted string literal] misfeature for DML statements
2321** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The
2322** default value of this setting is determined by the [-DSQLITE_DQS]
2323** compile-time option.
2324** </dd>
2325**
2326** [[SQLITE_DBCONFIG_DQS_DDL]]
2327** <dt>SQLITE_DBCONFIG_DQS_DDL</td>
2328** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates
2329** the legacy [double-quoted string literal] misfeature for DDL statements,
2330** such as CREATE TABLE and CREATE INDEX. The
2331** default value of this setting is determined by the [-DSQLITE_DQS]
2332** compile-time option.
2333** </dd>
2334**
2335** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]]
2336** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</td>
2337** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to
2338** assume that database schemas are untainted by malicious content.
2339** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite
2340** takes additional defensive steps to protect the application from harm
2341** including:
2342** <ul>
2343** <li> Prohibit the use of SQL functions inside triggers, views,
2344** CHECK constraints, DEFAULT clauses, expression indexes,
2345** partial indexes, or generated columns
2346** unless those functions are tagged with [SQLITE_INNOCUOUS].
2347** <li> Prohibit the use of virtual tables inside of triggers or views
2348** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS].
2349** </ul>
2350** This setting defaults to "on" for legacy compatibility, however
2351** all applications are advised to turn it off if possible. This setting
2352** can also be controlled using the [PRAGMA trusted_schema] statement.
2353** </dd>
2354**
2355** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]]
2356** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</td>
2357** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates
2358** the legacy file format flag. When activated, this flag causes all newly
2359** created database file to have a schema format version number (the 4-byte
2360** integer found at offset 44 into the database header) of 1. This in turn
2361** means that the resulting database file will be readable and writable by
2362** any SQLite version back to 3.0.0 ([dateof:3.0.0]). Without this setting,
2363** newly created databases are generally not understandable by SQLite versions
2364** prior to 3.3.0 ([dateof:3.3.0]). As these words are written, there
2365** is now scarcely any need to generated database files that are compatible
2366** all the way back to version 3.0.0, and so this setting is of little
2367** practical use, but is provided so that SQLite can continue to claim the
2368** ability to generate new database files that are compatible with version
2369** 3.0.0.
2370** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on,
2371** the [VACUUM] command will fail with an obscure error when attempting to
2372** process a table with generated columns and a descending index. This is
2373** not considered a bug since SQLite versions 3.3.0 and earlier do not support
2374** either generated columns or decending indexes.
2375** </dd>
2376** </dl>
2377*/
2378#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */
2379#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
2380#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
2381#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
2382#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
2383#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
2384#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */
2385#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */
2386#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */
2387#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */
2388#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */
2389#define SQLITE_DBCONFIG_WRITABLE_SCHEMA 1011 /* int int* */
2390#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE 1012 /* int int* */
2391#define SQLITE_DBCONFIG_DQS_DML 1013 /* int int* */
2392#define SQLITE_DBCONFIG_DQS_DDL 1014 /* int int* */
2393#define SQLITE_DBCONFIG_ENABLE_VIEW 1015 /* int int* */
2394#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT 1016 /* int int* */
2395#define SQLITE_DBCONFIG_TRUSTED_SCHEMA 1017 /* int int* */
2396#define SQLITE_DBCONFIG_MAX 1017 /* Largest DBCONFIG */
2397
2398/*
2399** CAPI3REF: Enable Or Disable Extended Result Codes
2400** METHOD: sqlite3
2401**
2402** ^The sqlite3_extended_result_codes() routine enables or disables the
2403** [extended result codes] feature of SQLite. ^The extended result
2404** codes are disabled by default for historical compatibility.
2405*/
2406
2407/*
2408** CAPI3REF: Last Insert Rowid
2409** METHOD: sqlite3
2410**
2411** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
2412** has a unique 64-bit signed
2413** integer key called the [ROWID | "rowid"]. ^The rowid is always available
2414** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
2415** names are not also used by explicitly declared columns. ^If
2416** the table has a column of type [INTEGER PRIMARY KEY] then that column
2417** is another alias for the rowid.
2418**
2419** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
2420** the most recent successful [INSERT] into a rowid table or [virtual table]
2421** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
2422** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
2423** on the database connection D, then sqlite3_last_insert_rowid(D) returns
2424** zero.
2425**
2426** As well as being set automatically as rows are inserted into database
2427** tables, the value returned by this function may be set explicitly by
2428** [sqlite3_set_last_insert_rowid()]
2429**
2430** Some virtual table implementations may INSERT rows into rowid tables as
2431** part of committing a transaction (e.g. to flush data accumulated in memory
2432** to disk). In this case subsequent calls to this function return the rowid
2433** associated with these internal INSERT operations, which leads to
2434** unintuitive results. Virtual table implementations that do write to rowid
2435** tables in this way can avoid this problem by restoring the original
2436** rowid value using [sqlite3_set_last_insert_rowid()] before returning
2437** control to the user.
2438**
2439** ^(If an [INSERT] occurs within a trigger then this routine will
2440** return the [rowid] of the inserted row as long as the trigger is
2441** running. Once the trigger program ends, the value returned
2442** by this routine reverts to what it was before the trigger was fired.)^
2443**
2444** ^An [INSERT] that fails due to a constraint violation is not a
2445** successful [INSERT] and does not change the value returned by this
2446** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
2447** and INSERT OR ABORT make no changes to the return value of this
2448** routine when their insertion fails. ^(When INSERT OR REPLACE
2449** encounters a constraint violation, it does not fail. The
2450** INSERT continues to completion after deleting rows that caused
2451** the constraint problem so INSERT OR REPLACE will always change
2452** the return value of this interface.)^
2453**
2454** ^For the purposes of this routine, an [INSERT] is considered to
2455** be successful even if it is subsequently rolled back.
2456**
2457** This function is accessible to SQL statements via the
2458** [last_insert_rowid() SQL function].
2459**
2460** If a separate thread performs a new [INSERT] on the same
2461** database connection while the [sqlite3_last_insert_rowid()]
2462** function is running and thus changes the last insert [rowid],
2463** then the value returned by [sqlite3_last_insert_rowid()] is
2464** unpredictable and might not equal either the old or the new
2465** last insert [rowid].
2466*/
2467
2468/*
2469** CAPI3REF: Set the Last Insert Rowid value.
2470** METHOD: sqlite3
2471**
2472** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
2473** set the value returned by calling sqlite3_last_insert_rowid(D) to R
2474** without inserting a row into the database.
2475*/
2476
2477/*
2478** CAPI3REF: Count The Number Of Rows Modified
2479** METHOD: sqlite3
2480**
2481** ^These functions return the number of rows modified, inserted or
2482** deleted by the most recently completed INSERT, UPDATE or DELETE
2483** statement on the database connection specified by the only parameter.
2484** The two functions are identical except for the type of the return value
2485** and that if the number of rows modified by the most recent INSERT, UPDATE
2486** or DELETE is greater than the maximum value supported by type "int", then
2487** the return value of sqlite3_changes() is undefined. ^Executing any other
2488** type of SQL statement does not modify the value returned by these functions.
2489**
2490** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
2491** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
2492** [foreign key actions] or [REPLACE] constraint resolution are not counted.
2493**
2494** Changes to a view that are intercepted by
2495** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
2496** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
2497** DELETE statement run on a view is always zero. Only changes made to real
2498** tables are counted.
2499**
2500** Things are more complicated if the sqlite3_changes() function is
2501** executed while a trigger program is running. This may happen if the
2502** program uses the [changes() SQL function], or if some other callback
2503** function invokes sqlite3_changes() directly. Essentially:
2504**
2505** <ul>
2506** <li> ^(Before entering a trigger program the value returned by
2507** sqlite3_changes() function is saved. After the trigger program
2508** has finished, the original value is restored.)^
2509**
2510** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
2511** statement sets the value returned by sqlite3_changes()
2512** upon completion as normal. Of course, this value will not include
2513** any changes performed by sub-triggers, as the sqlite3_changes()
2514** value will be saved and restored after each sub-trigger has run.)^
2515** </ul>
2516**
2517** ^This means that if the changes() SQL function (or similar) is used
2518** by the first INSERT, UPDATE or DELETE statement within a trigger, it
2519** returns the value as set when the calling statement began executing.
2520** ^If it is used by the second or subsequent such statement within a trigger
2521** program, the value returned reflects the number of rows modified by the
2522** previous INSERT, UPDATE or DELETE statement within the same trigger.
2523**
2524** If a separate thread makes changes on the same database connection
2525** while [sqlite3_changes()] is running then the value returned
2526** is unpredictable and not meaningful.
2527**
2528** See also:
2529** <ul>
2530** <li> the [sqlite3_total_changes()] interface
2531** <li> the [count_changes pragma]
2532** <li> the [changes() SQL function]
2533** <li> the [data_version pragma]
2534** </ul>
2535*/
2536
2537/*
2538** CAPI3REF: Total Number Of Rows Modified
2539** METHOD: sqlite3
2540**
2541** ^These functions return the total number of rows inserted, modified or
2542** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2543** since the database connection was opened, including those executed as
2544** part of trigger programs. The two functions are identical except for the
2545** type of the return value and that if the number of rows modified by the
2546** connection exceeds the maximum value supported by type "int", then
2547** the return value of sqlite3_total_changes() is undefined. ^Executing
2548** any other type of SQL statement does not affect the value returned by
2549** sqlite3_total_changes().
2550**
2551** ^Changes made as part of [foreign key actions] are included in the
2552** count, but those made as part of REPLACE constraint resolution are
2553** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2554** are not counted.
2555**
2556** The [sqlite3_total_changes(D)] interface only reports the number
2557** of rows that changed due to SQL statement run against database
2558** connection D. Any changes by other database connections are ignored.
2559** To detect changes against a database file from other database
2560** connections use the [PRAGMA data_version] command or the
2561** [SQLITE_FCNTL_DATA_VERSION] [file control].
2562**
2563** If a separate thread makes changes on the same database connection
2564** while [sqlite3_total_changes()] is running then the value
2565** returned is unpredictable and not meaningful.
2566**
2567** See also:
2568** <ul>
2569** <li> the [sqlite3_changes()] interface
2570** <li> the [count_changes pragma]
2571** <li> the [changes() SQL function]
2572** <li> the [data_version pragma]
2573** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control]
2574** </ul>
2575*/
2576
2577/*
2578** CAPI3REF: Interrupt A Long-Running Query
2579** METHOD: sqlite3
2580**
2581** ^This function causes any pending database operation to abort and
2582** return at its earliest opportunity. This routine is typically
2583** called in response to a user action such as pressing "Cancel"
2584** or Ctrl-C where the user wants a long query operation to halt
2585** immediately.
2586**
2587** ^It is safe to call this routine from a thread different from the
2588** thread that is currently running the database operation. But it
2589** is not safe to call this routine with a [database connection] that
2590** is closed or might close before sqlite3_interrupt() returns.
2591**
2592** ^If an SQL operation is very nearly finished at the time when
2593** sqlite3_interrupt() is called, then it might not have an opportunity
2594** to be interrupted and might continue to completion.
2595**
2596** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2597** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2598** that is inside an explicit transaction, then the entire transaction
2599** will be rolled back automatically.
2600**
2601** ^The sqlite3_interrupt(D) call is in effect until all currently running
2602** SQL statements on [database connection] D complete. ^Any new SQL statements
2603** that are started after the sqlite3_interrupt() call and before the
2604** running statement count reaches zero are interrupted as if they had been
2605** running prior to the sqlite3_interrupt() call. ^New SQL statements
2606** that are started after the running statement count reaches zero are
2607** not effected by the sqlite3_interrupt().
2608** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2609** SQL statements is a no-op and has no effect on SQL statements
2610** that are started after the sqlite3_interrupt() call returns.
2611*/
2612
2613/*
2614** CAPI3REF: Determine If An SQL Statement Is Complete
2615**
2616** These routines are useful during command-line input to determine if the
2617** currently entered text seems to form a complete SQL statement or
2618** if additional input is needed before sending the text into
2619** SQLite for parsing. ^These routines return 1 if the input string
2620** appears to be a complete SQL statement. ^A statement is judged to be
2621** complete if it ends with a semicolon token and is not a prefix of a
2622** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
2623** string literals or quoted identifier names or comments are not
2624** independent tokens (they are part of the token in which they are
2625** embedded) and thus do not count as a statement terminator. ^Whitespace
2626** and comments that follow the final semicolon are ignored.
2627**
2628** ^These routines return 0 if the statement is incomplete. ^If a
2629** memory allocation fails, then SQLITE_NOMEM is returned.
2630**
2631** ^These routines do not parse the SQL statements thus
2632** will not detect syntactically incorrect SQL.
2633**
2634** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2635** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2636** automatically by sqlite3_complete16(). If that initialization fails,
2637** then the return value from sqlite3_complete16() will be non-zero
2638** regardless of whether or not the input SQL is complete.)^
2639**
2640** The input to [sqlite3_complete()] must be a zero-terminated
2641** UTF-8 string.
2642**
2643** The input to [sqlite3_complete16()] must be a zero-terminated
2644** UTF-16 string in native byte order.
2645*/
2646
2647/*
2648** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2649** KEYWORDS: {busy-handler callback} {busy handler}
2650** METHOD: sqlite3
2651**
2652** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2653** that might be invoked with argument P whenever
2654** an attempt is made to access a database table associated with
2655** [database connection] D when another thread
2656** or process has the table locked.
2657** The sqlite3_busy_handler() interface is used to implement
2658** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2659**
2660** ^If the busy callback is NULL, then [SQLITE_BUSY]
2661** is returned immediately upon encountering the lock. ^If the busy callback
2662** is not NULL, then the callback might be invoked with two arguments.
2663**
2664** ^The first argument to the busy handler is a copy of the void* pointer which
2665** is the third argument to sqlite3_busy_handler(). ^The second argument to
2666** the busy handler callback is the number of times that the busy handler has
2667** been invoked previously for the same locking event. ^If the
2668** busy callback returns 0, then no additional attempts are made to
2669** access the database and [SQLITE_BUSY] is returned
2670** to the application.
2671** ^If the callback returns non-zero, then another attempt
2672** is made to access the database and the cycle repeats.
2673**
2674** The presence of a busy handler does not guarantee that it will be invoked
2675** when there is lock contention. ^If SQLite determines that invoking the busy
2676** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2677** to the application instead of invoking the
2678** busy handler.
2679** Consider a scenario where one process is holding a read lock that
2680** it is trying to promote to a reserved lock and
2681** a second process is holding a reserved lock that it is trying
2682** to promote to an exclusive lock. The first process cannot proceed
2683** because it is blocked by the second and the second process cannot
2684** proceed because it is blocked by the first. If both processes
2685** invoke the busy handlers, neither will make any progress. Therefore,
2686** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2687** will induce the first process to release its read lock and allow
2688** the second process to proceed.
2689**
2690** ^The default busy callback is NULL.
2691**
2692** ^(There can only be a single busy handler defined for each
2693** [database connection]. Setting a new busy handler clears any
2694** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
2695** or evaluating [PRAGMA busy_timeout=N] will change the
2696** busy handler and thus clear any previously set busy handler.
2697**
2698** The busy callback should not take any actions which modify the
2699** database connection that invoked the busy handler. In other words,
2700** the busy handler is not reentrant. Any such actions
2701** result in undefined behavior.
2702**
2703** A busy handler must not close the database connection
2704** or [prepared statement] that invoked the busy handler.
2705*/
2706
2707/*
2708** CAPI3REF: Set A Busy Timeout
2709** METHOD: sqlite3
2710**
2711** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2712** for a specified amount of time when a table is locked. ^The handler
2713** will sleep multiple times until at least "ms" milliseconds of sleeping
2714** have accumulated. ^After at least "ms" milliseconds of sleeping,
2715** the handler returns 0 which causes [sqlite3_step()] to return
2716** [SQLITE_BUSY].
2717**
2718** ^Calling this routine with an argument less than or equal to zero
2719** turns off all busy handlers.
2720**
2721** ^(There can only be a single busy handler for a particular
2722** [database connection] at any given moment. If another busy handler
2723** was defined (using [sqlite3_busy_handler()]) prior to calling
2724** this routine, that other busy handler is cleared.)^
2725**
2726** See also: [PRAGMA busy_timeout]
2727*/
2728
2729/*
2730** CAPI3REF: Convenience Routines For Running Queries
2731** METHOD: sqlite3
2732**
2733** This is a legacy interface that is preserved for backwards compatibility.
2734** Use of this interface is not recommended.
2735**
2736** Definition: A <b>result table</b> is memory data structure created by the
2737** [sqlite3_get_table()] interface. A result table records the
2738** complete query results from one or more queries.
2739**
2740** The table conceptually has a number of rows and columns. But
2741** these numbers are not part of the result table itself. These
2742** numbers are obtained separately. Let N be the number of rows
2743** and M be the number of columns.
2744**
2745** A result table is an array of pointers to zero-terminated UTF-8 strings.
2746** There are (N+1)*M elements in the array. The first M pointers point
2747** to zero-terminated strings that contain the names of the columns.
2748** The remaining entries all point to query results. NULL values result
2749** in NULL pointers. All other values are in their UTF-8 zero-terminated
2750** string representation as returned by [sqlite3_column_text()].
2751**
2752** A result table might consist of one or more memory allocations.
2753** It is not safe to pass a result table directly to [sqlite3_free()].
2754** A result table should be deallocated using [sqlite3_free_table()].
2755**
2756** ^(As an example of the result table format, suppose a query result
2757** is as follows:
2758**
2759** <blockquote><pre>
2760** Name | Age
2761** -----------------------
2762** Alice | 43
2763** Bob | 28
2764** Cindy | 21
2765** </pre></blockquote>
2766**
2767** There are two columns (M==2) and three rows (N==3). Thus the
2768** result table has 8 entries. Suppose the result table is stored
2769** in an array named azResult. Then azResult holds this content:
2770**
2771** <blockquote><pre>
2772** azResult&#91;0] = "Name";
2773** azResult&#91;1] = "Age";
2774** azResult&#91;2] = "Alice";
2775** azResult&#91;3] = "43";
2776** azResult&#91;4] = "Bob";
2777** azResult&#91;5] = "28";
2778** azResult&#91;6] = "Cindy";
2779** azResult&#91;7] = "21";
2780** </pre></blockquote>)^
2781**
2782** ^The sqlite3_get_table() function evaluates one or more
2783** semicolon-separated SQL statements in the zero-terminated UTF-8
2784** string of its 2nd parameter and returns a result table to the
2785** pointer given in its 3rd parameter.
2786**
2787** After the application has finished with the result from sqlite3_get_table(),
2788** it must pass the result table pointer to sqlite3_free_table() in order to
2789** release the memory that was malloced. Because of the way the
2790** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2791** function must not try to call [sqlite3_free()] directly. Only
2792** [sqlite3_free_table()] is able to release the memory properly and safely.
2793**
2794** The sqlite3_get_table() interface is implemented as a wrapper around
2795** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
2796** to any internal data structures of SQLite. It uses only the public
2797** interface defined here. As a consequence, errors that occur in the
2798** wrapper layer outside of the internal [sqlite3_exec()] call are not
2799** reflected in subsequent calls to [sqlite3_errcode()] or
2800** [sqlite3_errmsg()].
2801*/
2802
2803/*
2804** CAPI3REF: Formatted String Printing Functions
2805**
2806** These routines are work-alikes of the "printf()" family of functions
2807** from the standard C library.
2808** These routines understand most of the common formatting options from
2809** the standard library printf()
2810** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
2811** See the [built-in printf()] documentation for details.
2812**
2813** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2814** results into memory obtained from [sqlite3_malloc64()].
2815** The strings returned by these two routines should be
2816** released by [sqlite3_free()]. ^Both routines return a
2817** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
2818** memory to hold the resulting string.
2819**
2820** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2821** the standard C library. The result is written into the
2822** buffer supplied as the second parameter whose size is given by
2823** the first parameter. Note that the order of the
2824** first two parameters is reversed from snprintf().)^ This is an
2825** historical accident that cannot be fixed without breaking
2826** backwards compatibility. ^(Note also that sqlite3_snprintf()
2827** returns a pointer to its buffer instead of the number of
2828** characters actually written into the buffer.)^ We admit that
2829** the number of characters written would be a more useful return
2830** value but we cannot change the implementation of sqlite3_snprintf()
2831** now without breaking compatibility.
2832**
2833** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2834** guarantees that the buffer is always zero-terminated. ^The first
2835** parameter "n" is the total size of the buffer, including space for
2836** the zero terminator. So the longest string that can be completely
2837** written will be n-1 characters.
2838**
2839** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2840**
2841** See also: [built-in printf()], [printf() SQL function]
2842*/
2843
2844/*
2845** CAPI3REF: Memory Allocation Subsystem
2846**
2847** The SQLite core uses these three routines for all of its own
2848** internal memory allocation needs. "Core" in the previous sentence
2849** does not include operating-system specific [VFS] implementation. The
2850** Windows VFS uses native malloc() and free() for some operations.
2851**
2852** ^The sqlite3_malloc() routine returns a pointer to a block
2853** of memory at least N bytes in length, where N is the parameter.
2854** ^If sqlite3_malloc() is unable to obtain sufficient free
2855** memory, it returns a NULL pointer. ^If the parameter N to
2856** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2857** a NULL pointer.
2858**
2859** ^The sqlite3_malloc64(N) routine works just like
2860** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2861** of a signed 32-bit integer.
2862**
2863** ^Calling sqlite3_free() with a pointer previously returned
2864** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2865** that it might be reused. ^The sqlite3_free() routine is
2866** a no-op if is called with a NULL pointer. Passing a NULL pointer
2867** to sqlite3_free() is harmless. After being freed, memory
2868** should neither be read nor written. Even reading previously freed
2869** memory might result in a segmentation fault or other severe error.
2870** Memory corruption, a segmentation fault, or other severe error
2871** might result if sqlite3_free() is called with a non-NULL pointer that
2872** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2873**
2874** ^The sqlite3_realloc(X,N) interface attempts to resize a
2875** prior memory allocation X to be at least N bytes.
2876** ^If the X parameter to sqlite3_realloc(X,N)
2877** is a NULL pointer then its behavior is identical to calling
2878** sqlite3_malloc(N).
2879** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2880** negative then the behavior is exactly the same as calling
2881** sqlite3_free(X).
2882** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2883** of at least N bytes in size or NULL if insufficient memory is available.
2884** ^If M is the size of the prior allocation, then min(N,M) bytes
2885** of the prior allocation are copied into the beginning of buffer returned
2886** by sqlite3_realloc(X,N) and the prior allocation is freed.
2887** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2888** prior allocation is not freed.
2889**
2890** ^The sqlite3_realloc64(X,N) interfaces works the same as
2891** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2892** of a 32-bit signed integer.
2893**
2894** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2895** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2896** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2897** ^The value returned by sqlite3_msize(X) might be larger than the number
2898** of bytes requested when X was allocated. ^If X is a NULL pointer then
2899** sqlite3_msize(X) returns zero. If X points to something that is not
2900** the beginning of memory allocation, or if it points to a formerly
2901** valid memory allocation that has now been freed, then the behavior
2902** of sqlite3_msize(X) is undefined and possibly harmful.
2903**
2904** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2905** sqlite3_malloc64(), and sqlite3_realloc64()
2906** is always aligned to at least an 8 byte boundary, or to a
2907** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2908** option is used.
2909**
2910** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2911** must be either NULL or else pointers obtained from a prior
2912** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2913** not yet been released.
2914**
2915** The application must not read or write any part of
2916** a block of memory after it has been released using
2917** [sqlite3_free()] or [sqlite3_realloc()].
2918*/
2919
2920/*
2921** CAPI3REF: Memory Allocator Statistics
2922**
2923** SQLite provides these two interfaces for reporting on the status
2924** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2925** routines, which form the built-in memory allocation subsystem.
2926**
2927** ^The [sqlite3_memory_used()] routine returns the number of bytes
2928** of memory currently outstanding (malloced but not freed).
2929** ^The [sqlite3_memory_highwater()] routine returns the maximum
2930** value of [sqlite3_memory_used()] since the high-water mark
2931** was last reset. ^The values returned by [sqlite3_memory_used()] and
2932** [sqlite3_memory_highwater()] include any overhead
2933** added by SQLite in its implementation of [sqlite3_malloc()],
2934** but not overhead added by the any underlying system library
2935** routines that [sqlite3_malloc()] may call.
2936**
2937** ^The memory high-water mark is reset to the current value of
2938** [sqlite3_memory_used()] if and only if the parameter to
2939** [sqlite3_memory_highwater()] is true. ^The value returned
2940** by [sqlite3_memory_highwater(1)] is the high-water mark
2941** prior to the reset.
2942*/
2943
2944/*
2945** CAPI3REF: Pseudo-Random Number Generator
2946**
2947** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2948** select random [ROWID | ROWIDs] when inserting new records into a table that
2949** already uses the largest possible [ROWID]. The PRNG is also used for
2950** the built-in random() and randomblob() SQL functions. This interface allows
2951** applications to access the same PRNG for other purposes.
2952**
2953** ^A call to this routine stores N bytes of randomness into buffer P.
2954** ^The P parameter can be a NULL pointer.
2955**
2956** ^If this routine has not been previously called or if the previous
2957** call had N less than one or a NULL pointer for P, then the PRNG is
2958** seeded using randomness obtained from the xRandomness method of
2959** the default [sqlite3_vfs] object.
2960** ^If the previous call to this routine had an N of 1 or more and a
2961** non-NULL P then the pseudo-randomness is generated
2962** internally and without recourse to the [sqlite3_vfs] xRandomness
2963** method.
2964*/
2965
2966/*
2967** CAPI3REF: Compile-Time Authorization Callbacks
2968** METHOD: sqlite3
2969** KEYWORDS: {authorizer callback}
2970**
2971** ^This routine registers an authorizer callback with a particular
2972** [database connection], supplied in the first argument.
2973** ^The authorizer callback is invoked as SQL statements are being compiled
2974** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2975** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
2976** and [sqlite3_prepare16_v3()]. ^At various
2977** points during the compilation process, as logic is being created
2978** to perform various actions, the authorizer callback is invoked to
2979** see if those actions are allowed. ^The authorizer callback should
2980** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2981** specific action but allow the SQL statement to continue to be
2982** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2983** rejected with an error. ^If the authorizer callback returns
2984** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2985** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2986** the authorizer will fail with an error message.
2987**
2988** When the callback returns [SQLITE_OK], that means the operation
2989** requested is ok. ^When the callback returns [SQLITE_DENY], the
2990** [sqlite3_prepare_v2()] or equivalent call that triggered the
2991** authorizer will fail with an error message explaining that
2992** access is denied.
2993**
2994** ^The first parameter to the authorizer callback is a copy of the third
2995** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2996** to the callback is an integer [SQLITE_COPY | action code] that specifies
2997** the particular action to be authorized. ^The third through sixth parameters
2998** to the callback are either NULL pointers or zero-terminated strings
2999** that contain additional details about the action to be authorized.
3000** Applications must always be prepared to encounter a NULL pointer in any
3001** of the third through the sixth parameters of the authorization callback.
3002**
3003** ^If the action code is [SQLITE_READ]
3004** and the callback returns [SQLITE_IGNORE] then the
3005** [prepared statement] statement is constructed to substitute
3006** a NULL value in place of the table column that would have
3007** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
3008** return can be used to deny an untrusted user access to individual
3009** columns of a table.
3010** ^When a table is referenced by a [SELECT] but no column values are
3011** extracted from that table (for example in a query like
3012** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
3013** is invoked once for that table with a column name that is an empty string.
3014** ^If the action code is [SQLITE_DELETE] and the callback returns
3015** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
3016** [truncate optimization] is disabled and all rows are deleted individually.
3017**
3018** An authorizer is used when [sqlite3_prepare | preparing]
3019** SQL statements from an untrusted source, to ensure that the SQL statements
3020** do not try to access data they are not allowed to see, or that they do not
3021** try to execute malicious statements that damage the database. For
3022** example, an application may allow a user to enter arbitrary
3023** SQL queries for evaluation by a database. But the application does
3024** not want the user to be able to make arbitrary changes to the
3025** database. An authorizer could then be put in place while the
3026** user-entered SQL is being [sqlite3_prepare | prepared] that
3027** disallows everything except [SELECT] statements.
3028**
3029** Applications that need to process SQL from untrusted sources
3030** might also consider lowering resource limits using [sqlite3_limit()]
3031** and limiting database size using the [max_page_count] [PRAGMA]
3032** in addition to using an authorizer.
3033**
3034** ^(Only a single authorizer can be in place on a database connection
3035** at a time. Each call to sqlite3_set_authorizer overrides the
3036** previous call.)^ ^Disable the authorizer by installing a NULL callback.
3037** The authorizer is disabled by default.
3038**
3039** The authorizer callback must not do anything that will modify
3040** the database connection that invoked the authorizer callback.
3041** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3042** database connections for the meaning of "modify" in this paragraph.
3043**
3044** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
3045** statement might be re-prepared during [sqlite3_step()] due to a
3046** schema change. Hence, the application should ensure that the
3047** correct authorizer callback remains in place during the [sqlite3_step()].
3048**
3049** ^Note that the authorizer callback is invoked only during
3050** [sqlite3_prepare()] or its variants. Authorization is not
3051** performed during statement evaluation in [sqlite3_step()], unless
3052** as stated in the previous paragraph, sqlite3_step() invokes
3053** sqlite3_prepare_v2() to reprepare a statement after a schema change.
3054*/
3055
3056/*
3057** CAPI3REF: Authorizer Return Codes
3058**
3059** The [sqlite3_set_authorizer | authorizer callback function] must
3060** return either [SQLITE_OK] or one of these two constants in order
3061** to signal SQLite whether or not the action is permitted. See the
3062** [sqlite3_set_authorizer | authorizer documentation] for additional
3063** information.
3064**
3065** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
3066** returned from the [sqlite3_vtab_on_conflict()] interface.
3067*/
3068#define SQLITE_DENY 1 /* Abort the SQL statement with an error */
3069#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
3070
3071/*
3072** CAPI3REF: Authorizer Action Codes
3073**
3074** The [sqlite3_set_authorizer()] interface registers a callback function
3075** that is invoked to authorize certain SQL statement actions. The
3076** second parameter to the callback is an integer code that specifies
3077** what action is being authorized. These are the integer action codes that
3078** the authorizer callback may be passed.
3079**
3080** These action code values signify what kind of operation is to be
3081** authorized. The 3rd and 4th parameters to the authorization
3082** callback function will be parameters or NULL depending on which of these
3083** codes is used as the second parameter. ^(The 5th parameter to the
3084** authorizer callback is the name of the database ("main", "temp",
3085** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
3086** is the name of the inner-most trigger or view that is responsible for
3087** the access attempt or NULL if this access attempt is directly from
3088** top-level SQL code.
3089*/
3090/******************************************* 3rd ************ 4th ***********/
3091#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
3092#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
3093#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
3094#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
3095#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
3096#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
3097#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
3098#define SQLITE_CREATE_VIEW 8 /* View Name NULL */
3099#define SQLITE_DELETE 9 /* Table Name NULL */
3100#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
3101#define SQLITE_DROP_TABLE 11 /* Table Name NULL */
3102#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
3103#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
3104#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
3105#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
3106#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
3107#define SQLITE_DROP_VIEW 17 /* View Name NULL */
3108#define SQLITE_INSERT 18 /* Table Name NULL */
3109#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
3110#define SQLITE_READ 20 /* Table Name Column Name */
3111#define SQLITE_SELECT 21 /* NULL NULL */
3112#define SQLITE_TRANSACTION 22 /* Operation NULL */
3113#define SQLITE_UPDATE 23 /* Table Name Column Name */
3114#define SQLITE_ATTACH 24 /* Filename NULL */
3115#define SQLITE_DETACH 25 /* Database Name NULL */
3116#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
3117#define SQLITE_REINDEX 27 /* Index Name NULL */
3118#define SQLITE_ANALYZE 28 /* Table Name NULL */
3119#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
3120#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
3121#define SQLITE_FUNCTION 31 /* NULL Function Name */
3122#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
3123#define SQLITE_COPY 0 /* No longer used */
3124#define SQLITE_RECURSIVE 33 /* NULL NULL */
3125
3126/*
3127** CAPI3REF: Tracing And Profiling Functions
3128** METHOD: sqlite3
3129**
3130** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
3131** instead of the routines described here.
3132**
3133** These routines register callback functions that can be used for
3134** tracing and profiling the execution of SQL statements.
3135**
3136** ^The callback function registered by sqlite3_trace() is invoked at
3137** various times when an SQL statement is being run by [sqlite3_step()].
3138** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
3139** SQL statement text as the statement first begins executing.
3140** ^(Additional sqlite3_trace() callbacks might occur
3141** as each triggered subprogram is entered. The callbacks for triggers
3142** contain a UTF-8 SQL comment that identifies the trigger.)^
3143**
3144** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
3145** the length of [bound parameter] expansion in the output of sqlite3_trace().
3146**
3147** ^The callback function registered by sqlite3_profile() is invoked
3148** as each SQL statement finishes. ^The profile callback contains
3149** the original statement text and an estimate of wall-clock time
3150** of how long that statement took to run. ^The profile callback
3151** time is in units of nanoseconds, however the current implementation
3152** is only capable of millisecond resolution so the six least significant
3153** digits in the time are meaningless. Future versions of SQLite
3154** might provide greater resolution on the profiler callback. Invoking
3155** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the
3156** profile callback.
3157*/
3158
3159/*
3160** CAPI3REF: SQL Trace Event Codes
3161** KEYWORDS: SQLITE_TRACE
3162**
3163** These constants identify classes of events that can be monitored
3164** using the [sqlite3_trace_v2()] tracing logic. The M argument
3165** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
3166** the following constants. ^The first argument to the trace callback
3167** is one of the following constants.
3168**
3169** New tracing constants may be added in future releases.
3170**
3171** ^A trace callback has four arguments: xCallback(T,C,P,X).
3172** ^The T argument is one of the integer type codes above.
3173** ^The C argument is a copy of the context pointer passed in as the
3174** fourth argument to [sqlite3_trace_v2()].
3175** The P and X arguments are pointers whose meanings depend on T.
3176**
3177** <dl>
3178** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
3179** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
3180** first begins running and possibly at other times during the
3181** execution of the prepared statement, such as at the start of each
3182** trigger subprogram. ^The P argument is a pointer to the
3183** [prepared statement]. ^The X argument is a pointer to a string which
3184** is the unexpanded SQL text of the prepared statement or an SQL comment
3185** that indicates the invocation of a trigger. ^The callback can compute
3186** the same text that would have been returned by the legacy [sqlite3_trace()]
3187** interface by using the X argument when X begins with "--" and invoking
3188** [sqlite3_expanded_sql(P)] otherwise.
3189**
3190** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
3191** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
3192** information as is provided by the [sqlite3_profile()] callback.
3193** ^The P argument is a pointer to the [prepared statement] and the
3194** X argument points to a 64-bit integer which is the estimated of
3195** the number of nanosecond that the prepared statement took to run.
3196** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
3197**
3198** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
3199** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
3200** statement generates a single row of result.
3201** ^The P argument is a pointer to the [prepared statement] and the
3202** X argument is unused.
3203**
3204** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
3205** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
3206** connection closes.
3207** ^The P argument is a pointer to the [database connection] object
3208** and the X argument is unused.
3209** </dl>
3210*/
3211#define SQLITE_TRACE_STMT 0x01
3212#define SQLITE_TRACE_PROFILE 0x02
3213#define SQLITE_TRACE_ROW 0x04
3214#define SQLITE_TRACE_CLOSE 0x08
3215
3216/*
3217** CAPI3REF: SQL Trace Hook
3218** METHOD: sqlite3
3219**
3220** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
3221** function X against [database connection] D, using property mask M
3222** and context pointer P. ^If the X callback is
3223** NULL or if the M mask is zero, then tracing is disabled. The
3224** M argument should be the bitwise OR-ed combination of
3225** zero or more [SQLITE_TRACE] constants.
3226**
3227** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides
3228** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2().
3229**
3230** ^The X callback is invoked whenever any of the events identified by
3231** mask M occur. ^The integer return value from the callback is currently
3232** ignored, though this may change in future releases. Callback
3233** implementations should return zero to ensure future compatibility.
3234**
3235** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
3236** ^The T argument is one of the [SQLITE_TRACE]
3237** constants to indicate why the callback was invoked.
3238** ^The C argument is a copy of the context pointer.
3239** The P and X arguments are pointers whose meanings depend on T.
3240**
3241** The sqlite3_trace_v2() interface is intended to replace the legacy
3242** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
3243** are deprecated.
3244*/
3245
3246/*
3247** CAPI3REF: Query Progress Callbacks
3248** METHOD: sqlite3
3249**
3250** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
3251** function X to be invoked periodically during long running calls to
3252** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
3253** database connection D. An example use for this
3254** interface is to keep a GUI updated during a large query.
3255**
3256** ^The parameter P is passed through as the only parameter to the
3257** callback function X. ^The parameter N is the approximate number of
3258** [virtual machine instructions] that are evaluated between successive
3259** invocations of the callback X. ^If N is less than one then the progress
3260** handler is disabled.
3261**
3262** ^Only a single progress handler may be defined at one time per
3263** [database connection]; setting a new progress handler cancels the
3264** old one. ^Setting parameter X to NULL disables the progress handler.
3265** ^The progress handler is also disabled by setting N to a value less
3266** than 1.
3267**
3268** ^If the progress callback returns non-zero, the operation is
3269** interrupted. This feature can be used to implement a
3270** "Cancel" button on a GUI progress dialog box.
3271**
3272** The progress handler callback must not do anything that will modify
3273** the database connection that invoked the progress handler.
3274** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3275** database connections for the meaning of "modify" in this paragraph.
3276**
3277*/
3278
3279/*
3280** CAPI3REF: Opening A New Database Connection
3281** CONSTRUCTOR: sqlite3
3282**
3283** ^These routines open an SQLite database file as specified by the
3284** filename argument. ^The filename argument is interpreted as UTF-8 for
3285** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
3286** order for sqlite3_open16(). ^(A [database connection] handle is usually
3287** returned in *ppDb, even if an error occurs. The only exception is that
3288** if SQLite is unable to allocate memory to hold the [sqlite3] object,
3289** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
3290** object.)^ ^(If the database is opened (and/or created) successfully, then
3291** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
3292** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
3293** an English language description of the error following a failure of any
3294** of the sqlite3_open() routines.
3295**
3296** ^The default encoding will be UTF-8 for databases created using
3297** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases
3298** created using sqlite3_open16() will be UTF-16 in the native byte order.
3299**
3300** Whether or not an error occurs when it is opened, resources
3301** associated with the [database connection] handle should be released by
3302** passing it to [sqlite3_close()] when it is no longer required.
3303**
3304** The sqlite3_open_v2() interface works like sqlite3_open()
3305** except that it accepts two additional parameters for additional control
3306** over the new database connection. ^(The flags parameter to
3307** sqlite3_open_v2() must include, at a minimum, one of the following
3308** three flag combinations:)^
3309**
3310** <dl>
3311** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
3312** <dd>The database is opened in read-only mode. If the database does not
3313** already exist, an error is returned.</dd>)^
3314**
3315** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
3316** <dd>The database is opened for reading and writing if possible, or reading
3317** only if the file is write protected by the operating system. In either
3318** case the database must already exist, otherwise an error is returned.</dd>)^
3319**
3320** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
3321** <dd>The database is opened for reading and writing, and is created if
3322** it does not already exist. This is the behavior that is always used for
3323** sqlite3_open() and sqlite3_open16().</dd>)^
3324** </dl>
3325**
3326** In addition to the required flags, the following optional flags are
3327** also supported:
3328**
3329** <dl>
3330** ^(<dt>[SQLITE_OPEN_URI]</dt>
3331** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^
3332**
3333** ^(<dt>[SQLITE_OPEN_MEMORY]</dt>
3334** <dd>The database will be opened as an in-memory database. The database
3335** is named by the "filename" argument for the purposes of cache-sharing,
3336** if shared cache mode is enabled, but the "filename" is otherwise ignored.
3337** </dd>)^
3338**
3339** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt>
3340** <dd>The new database connection will use the "multi-thread"
3341** [threading mode].)^ This means that separate threads are allowed
3342** to use SQLite at the same time, as long as each thread is using
3343** a different [database connection].
3344**
3345** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt>
3346** <dd>The new database connection will use the "serialized"
3347** [threading mode].)^ This means the multiple threads can safely
3348** attempt to use the same database connection at the same time.
3349** (Mutexes will block any actual concurrency, but in this mode
3350** there is no harm in trying.)
3351**
3352** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt>
3353** <dd>The database is opened [shared cache] enabled, overriding
3354** the default shared cache setting provided by
3355** [sqlite3_enable_shared_cache()].)^
3356**
3357** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt>
3358** <dd>The database is opened [shared cache] disabled, overriding
3359** the default shared cache setting provided by
3360** [sqlite3_enable_shared_cache()].)^
3361**
3362** [[OPEN_EXRESCODE]] ^(<dt>[SQLITE_OPEN_EXRESCODE]</dt>
3363** <dd>The database connection comes up in "extended result code mode".
3364** In other words, the database behaves has if
3365** [sqlite3_extended_result_codes(db,1)] where called on the database
3366** connection as soon as the connection is created. In addition to setting
3367** the extended result code mode, this flag also causes [sqlite3_open_v2()]
3368** to return an extended result code.</dd>
3369**
3370** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt>
3371** <dd>The database filename is not allowed to be a symbolic link</dd>
3372** </dl>)^
3373**
3374** If the 3rd parameter to sqlite3_open_v2() is not one of the
3375** required combinations shown above optionally combined with other
3376** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
3377** then the behavior is undefined. Historic versions of SQLite
3378** have silently ignored surplus bits in the flags parameter to
3379** sqlite3_open_v2(), however that behavior might not be carried through
3380** into future versions of SQLite and so applications should not rely
3381** upon it. Note in particular that the SQLITE_OPEN_EXCLUSIVE flag is a no-op
3382** for sqlite3_open_v2(). The SQLITE_OPEN_EXCLUSIVE does *not* cause
3383** the open to fail if the database already exists. The SQLITE_OPEN_EXCLUSIVE
3384** flag is intended for use by the [sqlite3_vfs|VFS interface] only, and not
3385** by sqlite3_open_v2().
3386**
3387** ^The fourth parameter to sqlite3_open_v2() is the name of the
3388** [sqlite3_vfs] object that defines the operating system interface that
3389** the new database connection should use. ^If the fourth parameter is
3390** a NULL pointer then the default [sqlite3_vfs] object is used.
3391**
3392** ^If the filename is ":memory:", then a private, temporary in-memory database
3393** is created for the connection. ^This in-memory database will vanish when
3394** the database connection is closed. Future versions of SQLite might
3395** make use of additional special filenames that begin with the ":" character.
3396** It is recommended that when a database filename actually does begin with
3397** a ":" character you should prefix the filename with a pathname such as
3398** "./" to avoid ambiguity.
3399**
3400** ^If the filename is an empty string, then a private, temporary
3401** on-disk database will be created. ^This private database will be
3402** automatically deleted as soon as the database connection is closed.
3403**
3404** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
3405**
3406** ^If [URI filename] interpretation is enabled, and the filename argument
3407** begins with "file:", then the filename is interpreted as a URI. ^URI
3408** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
3409** set in the third argument to sqlite3_open_v2(), or if it has
3410** been enabled globally using the [SQLITE_CONFIG_URI] option with the
3411** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
3412** URI filename interpretation is turned off
3413** by default, but future releases of SQLite might enable URI filename
3414** interpretation by default. See "[URI filenames]" for additional
3415** information.
3416**
3417** URI filenames are parsed according to RFC 3986. ^If the URI contains an
3418** authority, then it must be either an empty string or the string
3419** "localhost". ^If the authority is not an empty string or "localhost", an
3420** error is returned to the caller. ^The fragment component of a URI, if
3421** present, is ignored.
3422**
3423** ^SQLite uses the path component of the URI as the name of the disk file
3424** which contains the database. ^If the path begins with a '/' character,
3425** then it is interpreted as an absolute path. ^If the path does not begin
3426** with a '/' (meaning that the authority section is omitted from the URI)
3427** then the path is interpreted as a relative path.
3428** ^(On windows, the first component of an absolute path
3429** is a drive specification (e.g. "C:").)^
3430**
3431** [[core URI query parameters]]
3432** The query component of a URI may contain parameters that are interpreted
3433** either by SQLite itself, or by a [VFS | custom VFS implementation].
3434** SQLite and its built-in [VFSes] interpret the
3435** following query parameters:
3436**
3437** <ul>
3438** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
3439** a VFS object that provides the operating system interface that should
3440** be used to access the database file on disk. ^If this option is set to
3441** an empty string the default VFS object is used. ^Specifying an unknown
3442** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
3443** present, then the VFS specified by the option takes precedence over
3444** the value passed as the fourth parameter to sqlite3_open_v2().
3445**
3446** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
3447** "rwc", or "memory". Attempting to set it to any other value is
3448** an error)^.
3449** ^If "ro" is specified, then the database is opened for read-only
3450** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
3451** third argument to sqlite3_open_v2(). ^If the mode option is set to
3452** "rw", then the database is opened for read-write (but not create)
3453** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
3454** been set. ^Value "rwc" is equivalent to setting both
3455** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
3456** set to "memory" then a pure [in-memory database] that never reads
3457** or writes from disk is used. ^It is an error to specify a value for
3458** the mode parameter that is less restrictive than that specified by
3459** the flags passed in the third parameter to sqlite3_open_v2().
3460**
3461** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
3462** "private". ^Setting it to "shared" is equivalent to setting the
3463** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
3464** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
3465** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
3466** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
3467** a URI filename, its value overrides any behavior requested by setting
3468** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
3469**
3470** <li> <b>psow</b>: ^The psow parameter indicates whether or not the
3471** [powersafe overwrite] property does or does not apply to the
3472** storage media on which the database file resides.
3473**
3474** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
3475** which if set disables file locking in rollback journal modes. This
3476** is useful for accessing a database on a filesystem that does not
3477** support locking. Caution: Database corruption might result if two
3478** or more processes write to the same database and any one of those
3479** processes uses nolock=1.
3480**
3481** <li> <b>immutable</b>: ^The immutable parameter is a boolean query
3482** parameter that indicates that the database file is stored on
3483** read-only media. ^When immutable is set, SQLite assumes that the
3484** database file cannot be changed, even by a process with higher
3485** privilege, and so the database is opened read-only and all locking
3486** and change detection is disabled. Caution: Setting the immutable
3487** property on a database file that does in fact change can result
3488** in incorrect query results and/or [SQLITE_CORRUPT] errors.
3489** See also: [SQLITE_IOCAP_IMMUTABLE].
3490**
3491** </ul>
3492**
3493** ^Specifying an unknown parameter in the query component of a URI is not an
3494** error. Future versions of SQLite might understand additional query
3495** parameters. See "[query parameters with special meaning to SQLite]" for
3496** additional information.
3497**
3498** [[URI filename examples]] <h3>URI filename examples</h3>
3499**
3500** <table border="1" align=center cellpadding=5>
3501** <tr><th> URI filenames <th> Results
3502** <tr><td> file:data.db <td>
3503** Open the file "data.db" in the current directory.
3504** <tr><td> file:/home/fred/data.db<br>
3505** file:///home/fred/data.db <br>
3506** file://localhost/home/fred/data.db <br> <td>
3507** Open the database file "/home/fred/data.db".
3508** <tr><td> file://darkstar/home/fred/data.db <td>
3509** An error. "darkstar" is not a recognized authority.
3510** <tr><td style="white-space:nowrap">
3511** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
3512** <td> Windows only: Open the file "data.db" on fred's desktop on drive
3513** C:. Note that the %20 escaping in this example is not strictly
3514** necessary - space characters can be used literally
3515** in URI filenames.
3516** <tr><td> file:data.db?mode=ro&cache=private <td>
3517** Open file "data.db" in the current directory for read-only access.
3518** Regardless of whether or not shared-cache mode is enabled by
3519** default, use a private cache.
3520** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
3521** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
3522** that uses dot-files in place of posix advisory locking.
3523** <tr><td> file:data.db?mode=readonly <td>
3524** An error. "readonly" is not a valid option for the "mode" parameter.
3525** Use "ro" instead: "file:data.db?mode=ro".
3526** </table>
3527**
3528** ^URI hexadecimal escape sequences (%HH) are supported within the path and
3529** query components of a URI. A hexadecimal escape sequence consists of a
3530** percent sign - "%" - followed by exactly two hexadecimal digits
3531** specifying an octet value. ^Before the path or query components of a
3532** URI filename are interpreted, they are encoded using UTF-8 and all
3533** hexadecimal escape sequences replaced by a single byte containing the
3534** corresponding octet. If this process generates an invalid UTF-8 encoding,
3535** the results are undefined.
3536**
3537** <b>Note to Windows users:</b> The encoding used for the filename argument
3538** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
3539** codepage is currently defined. Filenames containing international
3540** characters must be converted to UTF-8 prior to passing them into
3541** sqlite3_open() or sqlite3_open_v2().
3542**
3543** <b>Note to Windows Runtime users:</b> The temporary directory must be set
3544** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
3545** features that require the use of temporary files may fail.
3546**
3547** See also: [sqlite3_temp_directory]
3548*/
3549
3550/*
3551** CAPI3REF: Obtain Values For URI Parameters
3552**
3553** These are utility routines, useful to [VFS|custom VFS implementations],
3554** that check if a database file was a URI that contained a specific query
3555** parameter, and if so obtains the value of that query parameter.
3556**
3557** The first parameter to these interfaces (hereafter referred to
3558** as F) must be one of:
3559** <ul>
3560** <li> A database filename pointer created by the SQLite core and
3561** passed into the xOpen() method of a VFS implemention, or
3562** <li> A filename obtained from [sqlite3_db_filename()], or
3563** <li> A new filename constructed using [sqlite3_create_filename()].
3564** </ul>
3565** If the F parameter is not one of the above, then the behavior is
3566** undefined and probably undesirable. Older versions of SQLite were
3567** more tolerant of invalid F parameters than newer versions.
3568**
3569** If F is a suitable filename (as described in the previous paragraph)
3570** and if P is the name of the query parameter, then
3571** sqlite3_uri_parameter(F,P) returns the value of the P
3572** parameter if it exists or a NULL pointer if P does not appear as a
3573** query parameter on F. If P is a query parameter of F and it
3574** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3575** a pointer to an empty string.
3576**
3577** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3578** parameter and returns true (1) or false (0) according to the value
3579** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3580** value of query parameter P is one of "yes", "true", or "on" in any
3581** case or if the value begins with a non-zero number. The
3582** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3583** query parameter P is one of "no", "false", or "off" in any case or
3584** if the value begins with a numeric zero. If P is not a query
3585** parameter on F or if the value of P does not match any of the
3586** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3587**
3588** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3589** 64-bit signed integer and returns that integer, or D if P does not
3590** exist. If the value of P is something other than an integer, then
3591** zero is returned.
3592**
3593** The sqlite3_uri_key(F,N) returns a pointer to the name (not
3594** the value) of the N-th query parameter for filename F, or a NULL
3595** pointer if N is less than zero or greater than the number of query
3596** parameters minus 1. The N value is zero-based so N should be 0 to obtain
3597** the name of the first query parameter, 1 for the second parameter, and
3598** so forth.
3599**
3600** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3601** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
3602** is not a database file pathname pointer that the SQLite core passed
3603** into the xOpen VFS method, then the behavior of this routine is undefined
3604** and probably undesirable.
3605**
3606** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F
3607** parameter can also be the name of a rollback journal file or WAL file
3608** in addition to the main database file. Prior to version 3.31.0, these
3609** routines would only work if F was the name of the main database file.
3610** When the F parameter is the name of the rollback journal or WAL file,
3611** it has access to all the same query parameters as were found on the
3612** main database file.
3613**
3614** See the [URI filename] documentation for additional information.
3615*/
3616
3617/*
3618** CAPI3REF: Translate filenames
3619**
3620** These routines are available to [VFS|custom VFS implementations] for
3621** translating filenames between the main database file, the journal file,
3622** and the WAL file.
3623**
3624** If F is the name of an sqlite database file, journal file, or WAL file
3625** passed by the SQLite core into the VFS, then sqlite3_filename_database(F)
3626** returns the name of the corresponding database file.
3627**
3628** If F is the name of an sqlite database file, journal file, or WAL file
3629** passed by the SQLite core into the VFS, or if F is a database filename
3630** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F)
3631** returns the name of the corresponding rollback journal file.
3632**
3633** If F is the name of an sqlite database file, journal file, or WAL file
3634** that was passed by the SQLite core into the VFS, or if F is a database
3635** filename obtained from [sqlite3_db_filename()], then
3636** sqlite3_filename_wal(F) returns the name of the corresponding
3637** WAL file.
3638**
3639** In all of the above, if F is not the name of a database, journal or WAL
3640** filename passed into the VFS from the SQLite core and F is not the
3641** return value from [sqlite3_db_filename()], then the result is
3642** undefined and is likely a memory access violation.
3643*/
3644
3645/*
3646** CAPI3REF: Database File Corresponding To A Journal
3647**
3648** ^If X is the name of a rollback or WAL-mode journal file that is
3649** passed into the xOpen method of [sqlite3_vfs], then
3650** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file]
3651** object that represents the main database file.
3652**
3653** This routine is intended for use in custom [VFS] implementations
3654** only. It is not a general-purpose interface.
3655** The argument sqlite3_file_object(X) must be a filename pointer that
3656** has been passed into [sqlite3_vfs].xOpen method where the
3657** flags parameter to xOpen contains one of the bits
3658** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL]. Any other use
3659** of this routine results in undefined and probably undesirable
3660** behavior.
3661*/
3662
3663/*
3664** CAPI3REF: Create and Destroy VFS Filenames
3665**
3666** These interfces are provided for use by [VFS shim] implementations and
3667** are not useful outside of that context.
3668**
3669** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of
3670** database filename D with corresponding journal file J and WAL file W and
3671** with N URI parameters key/values pairs in the array P. The result from
3672** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that
3673** is safe to pass to routines like:
3674** <ul>
3675** <li> [sqlite3_uri_parameter()],
3676** <li> [sqlite3_uri_boolean()],
3677** <li> [sqlite3_uri_int64()],
3678** <li> [sqlite3_uri_key()],
3679** <li> [sqlite3_filename_database()],
3680** <li> [sqlite3_filename_journal()], or
3681** <li> [sqlite3_filename_wal()].
3682** </ul>
3683** If a memory allocation error occurs, sqlite3_create_filename() might
3684** return a NULL pointer. The memory obtained from sqlite3_create_filename(X)
3685** must be released by a corresponding call to sqlite3_free_filename(Y).
3686**
3687** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array
3688** of 2*N pointers to strings. Each pair of pointers in this array corresponds
3689** to a key and value for a query parameter. The P parameter may be a NULL
3690** pointer if N is zero. None of the 2*N pointers in the P array may be
3691** NULL pointers and key pointers should not be empty strings.
3692** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may
3693** be NULL pointers, though they can be empty strings.
3694**
3695** The sqlite3_free_filename(Y) routine releases a memory allocation
3696** previously obtained from sqlite3_create_filename(). Invoking
3697** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op.
3698**
3699** If the Y parameter to sqlite3_free_filename(Y) is anything other
3700** than a NULL pointer or a pointer previously acquired from
3701** sqlite3_create_filename(), then bad things such as heap
3702** corruption or segfaults may occur. The value Y should not be
3703** used again after sqlite3_free_filename(Y) has been called. This means
3704** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y,
3705** then the corresponding [sqlite3_module.xClose() method should also be
3706** invoked prior to calling sqlite3_free_filename(Y).
3707*/
3708
3709/*
3710** CAPI3REF: Error Codes And Messages
3711** METHOD: sqlite3
3712**
3713** ^If the most recent sqlite3_* API call associated with
3714** [database connection] D failed, then the sqlite3_errcode(D) interface
3715** returns the numeric [result code] or [extended result code] for that
3716** API call.
3717** ^The sqlite3_extended_errcode()
3718** interface is the same except that it always returns the
3719** [extended result code] even when extended result codes are
3720** disabled.
3721**
3722** The values returned by sqlite3_errcode() and/or
3723** sqlite3_extended_errcode() might change with each API call.
3724** Except, there are some interfaces that are guaranteed to never
3725** change the value of the error code. The error-code preserving
3726** interfaces include the following:
3727**
3728** <ul>
3729** <li> sqlite3_errcode()
3730** <li> sqlite3_extended_errcode()
3731** <li> sqlite3_errmsg()
3732** <li> sqlite3_errmsg16()
3733** <li> sqlite3_error_offset()
3734** </ul>
3735**
3736** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3737** text that describes the error, as either UTF-8 or UTF-16 respectively.
3738** ^(Memory to hold the error message string is managed internally.
3739** The application does not need to worry about freeing the result.
3740** However, the error string might be overwritten or deallocated by
3741** subsequent calls to other SQLite interface functions.)^
3742**
3743** ^The sqlite3_errstr() interface returns the English-language text
3744** that describes the [result code], as UTF-8.
3745** ^(Memory to hold the error message string is managed internally
3746** and must not be freed by the application)^.
3747**
3748** ^If the most recent error references a specific token in the input
3749** SQL, the sqlite3_error_offset() interface returns the byte offset
3750** of the start of that token. ^The byte offset returned by
3751** sqlite3_error_offset() assumes that the input SQL is UTF8.
3752** ^If the most recent error does not reference a specific token in the input
3753** SQL, then the sqlite3_error_offset() function returns -1.
3754**
3755** When the serialized [threading mode] is in use, it might be the
3756** case that a second error occurs on a separate thread in between
3757** the time of the first error and the call to these interfaces.
3758** When that happens, the second error will be reported since these
3759** interfaces always report the most recent result. To avoid
3760** this, each thread can obtain exclusive use of the [database connection] D
3761** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3762** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3763** all calls to the interfaces listed here are completed.
3764**
3765** If an interface fails with SQLITE_MISUSE, that means the interface
3766** was invoked incorrectly by the application. In that case, the
3767** error code and message may or may not be set.
3768*/
3769
3770/*
3771** CAPI3REF: Prepared Statement Object
3772** KEYWORDS: {prepared statement} {prepared statements}
3773**
3774** An instance of this object represents a single SQL statement that
3775** has been compiled into binary form and is ready to be evaluated.
3776**
3777** Think of each SQL statement as a separate computer program. The
3778** original SQL text is source code. A prepared statement object
3779** is the compiled object code. All SQL must be converted into a
3780** prepared statement before it can be run.
3781**
3782** The life-cycle of a prepared statement object usually goes like this:
3783**
3784** <ol>
3785** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
3786** <li> Bind values to [parameters] using the sqlite3_bind_*()
3787** interfaces.
3788** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3789** <li> Reset the prepared statement using [sqlite3_reset()] then go back
3790** to step 2. Do this zero or more times.
3791** <li> Destroy the object using [sqlite3_finalize()].
3792** </ol>
3793*/
3794typedef struct sqlite3_stmt sqlite3_stmt;
3795
3796/*
3797** CAPI3REF: Run-time Limits
3798** METHOD: sqlite3
3799**
3800** ^(This interface allows the size of various constructs to be limited
3801** on a connection by connection basis. The first parameter is the
3802** [database connection] whose limit is to be set or queried. The
3803** second parameter is one of the [limit categories] that define a
3804** class of constructs to be size limited. The third parameter is the
3805** new limit for that construct.)^
3806**
3807** ^If the new limit is a negative number, the limit is unchanged.
3808** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3809** [limits | hard upper bound]
3810** set at compile-time by a C preprocessor macro called
3811** [limits | SQLITE_MAX_<i>NAME</i>].
3812** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3813** ^Attempts to increase a limit above its hard upper bound are
3814** silently truncated to the hard upper bound.
3815**
3816** ^Regardless of whether or not the limit was changed, the
3817** [sqlite3_limit()] interface returns the prior value of the limit.
3818** ^Hence, to find the current value of a limit without changing it,
3819** simply invoke this interface with the third parameter set to -1.
3820**
3821** Run-time limits are intended for use in applications that manage
3822** both their own internal database and also databases that are controlled
3823** by untrusted external sources. An example application might be a
3824** web browser that has its own databases for storing history and
3825** separate databases controlled by JavaScript applications downloaded
3826** off the Internet. The internal databases can be given the
3827** large, default limits. Databases managed by external sources can
3828** be given much smaller limits designed to prevent a denial of service
3829** attack. Developers might also want to use the [sqlite3_set_authorizer()]
3830** interface to further control untrusted SQL. The size of the database
3831** created by an untrusted script can be contained using the
3832** [max_page_count] [PRAGMA].
3833**
3834** New run-time limit categories may be added in future releases.
3835*/
3836
3837/*
3838** CAPI3REF: Run-Time Limit Categories
3839** KEYWORDS: {limit category} {*limit categories}
3840**
3841** These constants define various performance limits
3842** that can be lowered at run-time using [sqlite3_limit()].
3843** The synopsis of the meanings of the various limits is shown below.
3844** Additional information is available at [limits | Limits in SQLite].
3845**
3846** <dl>
3847** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3848** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3849**
3850** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3851** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3852**
3853** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3854** <dd>The maximum number of columns in a table definition or in the
3855** result set of a [SELECT] or the maximum number of columns in an index
3856** or in an ORDER BY or GROUP BY clause.</dd>)^
3857**
3858** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3859** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3860**
3861** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3862** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3863**
3864** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3865** <dd>The maximum number of instructions in a virtual machine program
3866** used to implement an SQL statement. If [sqlite3_prepare_v2()] or
3867** the equivalent tries to allocate space for more than this many opcodes
3868** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
3869**
3870** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3871** <dd>The maximum number of arguments on a function.</dd>)^
3872**
3873** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3874** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3875**
3876** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3877** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3878** <dd>The maximum length of the pattern argument to the [LIKE] or
3879** [GLOB] operators.</dd>)^
3880**
3881** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3882** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3883** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3884**
3885** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3886** <dd>The maximum depth of recursion for triggers.</dd>)^
3887**
3888** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
3889** <dd>The maximum number of auxiliary worker threads that a single
3890** [prepared statement] may start.</dd>)^
3891** </dl>
3892*/
3893#define SQLITE_LIMIT_LENGTH 0
3894#define SQLITE_LIMIT_SQL_LENGTH 1
3895#define SQLITE_LIMIT_COLUMN 2
3896#define SQLITE_LIMIT_EXPR_DEPTH 3
3897#define SQLITE_LIMIT_COMPOUND_SELECT 4
3898#define SQLITE_LIMIT_VDBE_OP 5
3899#define SQLITE_LIMIT_FUNCTION_ARG 6
3900#define SQLITE_LIMIT_ATTACHED 7
3901#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
3902#define SQLITE_LIMIT_VARIABLE_NUMBER 9
3903#define SQLITE_LIMIT_TRIGGER_DEPTH 10
3904#define SQLITE_LIMIT_WORKER_THREADS 11
3905
3906/*
3907** CAPI3REF: Prepare Flags
3908**
3909** These constants define various flags that can be passed into
3910** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
3911** [sqlite3_prepare16_v3()] interfaces.
3912**
3913** New flags may be added in future releases of SQLite.
3914**
3915** <dl>
3916** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
3917** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
3918** that the prepared statement will be retained for a long time and
3919** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
3920** and [sqlite3_prepare16_v3()] assume that the prepared statement will
3921** be used just once or at most a few times and then destroyed using
3922** [sqlite3_finalize()] relatively soon. The current implementation acts
3923** on this hint by avoiding the use of [lookaside memory] so as not to
3924** deplete the limited store of lookaside memory. Future versions of
3925** SQLite may act on this hint differently.
3926**
3927** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt>
3928** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
3929** to be required for any prepared statement that wanted to use the
3930** [sqlite3_normalized_sql()] interface. However, the
3931** [sqlite3_normalized_sql()] interface is now available to all
3932** prepared statements, regardless of whether or not they use this
3933** flag.
3934**
3935** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt>
3936** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
3937** to return an error (error code SQLITE_ERROR) if the statement uses
3938** any virtual tables.
3939** </dl>
3940*/
3941#define SQLITE_PREPARE_PERSISTENT 0x01
3942#define SQLITE_PREPARE_NORMALIZE 0x02
3943#define SQLITE_PREPARE_NO_VTAB 0x04
3944
3945/*
3946** CAPI3REF: Compiling An SQL Statement
3947** KEYWORDS: {SQL statement compiler}
3948** METHOD: sqlite3
3949** CONSTRUCTOR: sqlite3_stmt
3950**
3951** To execute an SQL statement, it must first be compiled into a byte-code
3952** program using one of these routines. Or, in other words, these routines
3953** are constructors for the [prepared statement] object.
3954**
3955** The preferred routine to use is [sqlite3_prepare_v2()]. The
3956** [sqlite3_prepare()] interface is legacy and should be avoided.
3957** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
3958** for special purposes.
3959**
3960** The use of the UTF-8 interfaces is preferred, as SQLite currently
3961** does all parsing using UTF-8. The UTF-16 interfaces are provided
3962** as a convenience. The UTF-16 interfaces work by converting the
3963** input text into UTF-8, then invoking the corresponding UTF-8 interface.
3964**
3965** The first argument, "db", is a [database connection] obtained from a
3966** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3967** [sqlite3_open16()]. The database connection must not have been closed.
3968**
3969** The second argument, "zSql", is the statement to be compiled, encoded
3970** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(),
3971** and sqlite3_prepare_v3()
3972** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
3973** and sqlite3_prepare16_v3() use UTF-16.
3974**
3975** ^If the nByte argument is negative, then zSql is read up to the
3976** first zero terminator. ^If nByte is positive, then it is the
3977** number of bytes read from zSql. ^If nByte is zero, then no prepared
3978** statement is generated.
3979** If the caller knows that the supplied string is nul-terminated, then
3980** there is a small performance advantage to passing an nByte parameter that
3981** is the number of bytes in the input string <i>including</i>
3982** the nul-terminator.
3983**
3984** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3985** past the end of the first SQL statement in zSql. These routines only
3986** compile the first statement in zSql, so *pzTail is left pointing to
3987** what remains uncompiled.
3988**
3989** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3990** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
3991** to NULL. ^If the input text contains no SQL (if the input is an empty
3992** string or a comment) then *ppStmt is set to NULL.
3993** The calling procedure is responsible for deleting the compiled
3994** SQL statement using [sqlite3_finalize()] after it has finished with it.
3995** ppStmt may not be NULL.
3996**
3997** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3998** otherwise an [error code] is returned.
3999**
4000** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
4001** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
4002** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
4003** are retained for backwards compatibility, but their use is discouraged.
4004** ^In the "vX" interfaces, the prepared statement
4005** that is returned (the [sqlite3_stmt] object) contains a copy of the
4006** original SQL text. This causes the [sqlite3_step()] interface to
4007** behave differently in three ways:
4008**
4009** <ol>
4010** <li>
4011** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
4012** always used to do, [sqlite3_step()] will automatically recompile the SQL
4013** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
4014** retries will occur before sqlite3_step() gives up and returns an error.
4015** </li>
4016**
4017** <li>
4018** ^When an error occurs, [sqlite3_step()] will return one of the detailed
4019** [error codes] or [extended error codes]. ^The legacy behavior was that
4020** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
4021** and the application would have to make a second call to [sqlite3_reset()]
4022** in order to find the underlying cause of the problem. With the "v2" prepare
4023** interfaces, the underlying reason for the error is returned immediately.
4024** </li>
4025**
4026** <li>
4027** ^If the specific value bound to a [parameter | host parameter] in the
4028** WHERE clause might influence the choice of query plan for a statement,
4029** then the statement will be automatically recompiled, as if there had been
4030** a schema change, on the first [sqlite3_step()] call following any change
4031** to the [sqlite3_bind_text | bindings] of that [parameter].
4032** ^The specific value of a WHERE-clause [parameter] might influence the
4033** choice of query plan if the parameter is the left-hand side of a [LIKE]
4034** or [GLOB] operator or if the parameter is compared to an indexed column
4035** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled.
4036** </li>
4037** </ol>
4038**
4039** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
4040** the extra prepFlags parameter, which is a bit array consisting of zero or
4041** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The
4042** sqlite3_prepare_v2() interface works exactly the same as
4043** sqlite3_prepare_v3() with a zero prepFlags parameter.
4044*/
4045
4046/*
4047** CAPI3REF: Retrieving Statement SQL
4048** METHOD: sqlite3_stmt
4049**
4050** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
4051** SQL text used to create [prepared statement] P if P was
4052** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
4053** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4054** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
4055** string containing the SQL text of prepared statement P with
4056** [bound parameters] expanded.
4057** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
4058** string containing the normalized SQL text of prepared statement P. The
4059** semantics used to normalize a SQL statement are unspecified and subject
4060** to change. At a minimum, literal values will be replaced with suitable
4061** placeholders.
4062**
4063** ^(For example, if a prepared statement is created using the SQL
4064** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
4065** and parameter :xyz is unbound, then sqlite3_sql() will return
4066** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
4067** will return "SELECT 2345,NULL".)^
4068**
4069** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
4070** is available to hold the result, or if the result would exceed the
4071** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
4072**
4073** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
4074** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time
4075** option causes sqlite3_expanded_sql() to always return NULL.
4076**
4077** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
4078** are managed by SQLite and are automatically freed when the prepared
4079** statement is finalized.
4080** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
4081** is obtained from [sqlite3_malloc()] and must be freed by the application
4082** by passing it to [sqlite3_free()].
4083**
4084** ^The sqlite3_normalized_sql() interface is only available if
4085** the [SQLITE_ENABLE_NORMALIZE] compile-time option is defined.
4086*/
4087#ifdef SQLITE_ENABLE_NORMALIZE
4088#endif
4089
4090/*
4091** CAPI3REF: Determine If An SQL Statement Writes The Database
4092** METHOD: sqlite3_stmt
4093**
4094** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
4095** and only if the [prepared statement] X makes no direct changes to
4096** the content of the database file.
4097**
4098** Note that [application-defined SQL functions] or
4099** [virtual tables] might change the database indirectly as a side effect.
4100** ^(For example, if an application defines a function "eval()" that
4101** calls [sqlite3_exec()], then the following SQL statement would
4102** change the database file through side-effects:
4103**
4104** <blockquote><pre>
4105** SELECT eval('DELETE FROM t1') FROM t2;
4106** </pre></blockquote>
4107**
4108** But because the [SELECT] statement does not change the database file
4109** directly, sqlite3_stmt_readonly() would still return true.)^
4110**
4111** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
4112** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
4113** since the statements themselves do not actually modify the database but
4114** rather they control the timing of when other statements modify the
4115** database. ^The [ATTACH] and [DETACH] statements also cause
4116** sqlite3_stmt_readonly() to return true since, while those statements
4117** change the configuration of a database connection, they do not make
4118** changes to the content of the database files on disk.
4119** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
4120** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
4121** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
4122** sqlite3_stmt_readonly() returns false for those commands.
4123**
4124** ^This routine returns false if there is any possibility that the
4125** statement might change the database file. ^A false return does
4126** not guarantee that the statement will change the database file.
4127** ^For example, an UPDATE statement might have a WHERE clause that
4128** makes it a no-op, but the sqlite3_stmt_readonly() result would still
4129** be false. ^Similarly, a CREATE TABLE IF NOT EXISTS statement is a
4130** read-only no-op if the table already exists, but
4131** sqlite3_stmt_readonly() still returns false for such a statement.
4132**
4133** ^If prepared statement X is an [EXPLAIN] or [EXPLAIN QUERY PLAN]
4134** statement, then sqlite3_stmt_readonly(X) returns the same value as
4135** if the EXPLAIN or EXPLAIN QUERY PLAN prefix were omitted.
4136*/
4137
4138/*
4139** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement
4140** METHOD: sqlite3_stmt
4141**
4142** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the
4143** prepared statement S is an EXPLAIN statement, or 2 if the
4144** statement S is an EXPLAIN QUERY PLAN.
4145** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is
4146** an ordinary statement or a NULL pointer.
4147*/
4148
4149/*
4150** CAPI3REF: Determine If A Prepared Statement Has Been Reset
4151** METHOD: sqlite3_stmt
4152**
4153** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
4154** [prepared statement] S has been stepped at least once using
4155** [sqlite3_step(S)] but has neither run to completion (returned
4156** [SQLITE_DONE] from [sqlite3_step(S)]) nor
4157** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
4158** interface returns false if S is a NULL pointer. If S is not a
4159** NULL pointer and is not a pointer to a valid [prepared statement]
4160** object, then the behavior is undefined and probably undesirable.
4161**
4162** This interface can be used in combination [sqlite3_next_stmt()]
4163** to locate all prepared statements associated with a database
4164** connection that are in need of being reset. This can be used,
4165** for example, in diagnostic routines to search for prepared
4166** statements that are holding a transaction open.
4167*/
4168
4169/*
4170** CAPI3REF: Dynamically Typed Value Object
4171** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
4172**
4173** SQLite uses the sqlite3_value object to represent all values
4174** that can be stored in a database table. SQLite uses dynamic typing
4175** for the values it stores. ^Values stored in sqlite3_value objects
4176** can be integers, floating point values, strings, BLOBs, or NULL.
4177**
4178** An sqlite3_value object may be either "protected" or "unprotected".
4179** Some interfaces require a protected sqlite3_value. Other interfaces
4180** will accept either a protected or an unprotected sqlite3_value.
4181** Every interface that accepts sqlite3_value arguments specifies
4182** whether or not it requires a protected sqlite3_value. The
4183** [sqlite3_value_dup()] interface can be used to construct a new
4184** protected sqlite3_value from an unprotected sqlite3_value.
4185**
4186** The terms "protected" and "unprotected" refer to whether or not
4187** a mutex is held. An internal mutex is held for a protected
4188** sqlite3_value object but no mutex is held for an unprotected
4189** sqlite3_value object. If SQLite is compiled to be single-threaded
4190** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
4191** or if SQLite is run in one of reduced mutex modes
4192** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
4193** then there is no distinction between protected and unprotected
4194** sqlite3_value objects and they can be used interchangeably. However,
4195** for maximum code portability it is recommended that applications
4196** still make the distinction between protected and unprotected
4197** sqlite3_value objects even when not strictly required.
4198**
4199** ^The sqlite3_value objects that are passed as parameters into the
4200** implementation of [application-defined SQL functions] are protected.
4201** ^The sqlite3_value objects returned by [sqlite3_vtab_rhs_value()]
4202** are protected.
4203** ^The sqlite3_value object returned by
4204** [sqlite3_column_value()] is unprotected.
4205** Unprotected sqlite3_value objects may only be used as arguments
4206** to [sqlite3_result_value()], [sqlite3_bind_value()], and
4207** [sqlite3_value_dup()].
4208** The [sqlite3_value_blob | sqlite3_value_type()] family of
4209** interfaces require protected sqlite3_value objects.
4210*/
4211typedef struct sqlite3_value sqlite3_value;
4212
4213/*
4214** CAPI3REF: SQL Function Context Object
4215**
4216** The context in which an SQL function executes is stored in an
4217** sqlite3_context object. ^A pointer to an sqlite3_context object
4218** is always first parameter to [application-defined SQL functions].
4219** The application-defined SQL function implementation will pass this
4220** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
4221** [sqlite3_aggregate_context()], [sqlite3_user_data()],
4222** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
4223** and/or [sqlite3_set_auxdata()].
4224*/
4225typedef struct sqlite3_context sqlite3_context;
4226
4227/*
4228** CAPI3REF: Binding Values To Prepared Statements
4229** KEYWORDS: {host parameter} {host parameters} {host parameter name}
4230** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
4231** METHOD: sqlite3_stmt
4232**
4233** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
4234** literals may be replaced by a [parameter] that matches one of following
4235** templates:
4236**
4237** <ul>
4238** <li> ?
4239** <li> ?NNN
4240** <li> :VVV
4241** <li> @VVV
4242** <li> $VVV
4243** </ul>
4244**
4245** In the templates above, NNN represents an integer literal,
4246** and VVV represents an alphanumeric identifier.)^ ^The values of these
4247** parameters (also called "host parameter names" or "SQL parameters")
4248** can be set using the sqlite3_bind_*() routines defined here.
4249**
4250** ^The first argument to the sqlite3_bind_*() routines is always
4251** a pointer to the [sqlite3_stmt] object returned from
4252** [sqlite3_prepare_v2()] or its variants.
4253**
4254** ^The second argument is the index of the SQL parameter to be set.
4255** ^The leftmost SQL parameter has an index of 1. ^When the same named
4256** SQL parameter is used more than once, second and subsequent
4257** occurrences have the same index as the first occurrence.
4258** ^The index for named parameters can be looked up using the
4259** [sqlite3_bind_parameter_index()] API if desired. ^The index
4260** for "?NNN" parameters is the value of NNN.
4261** ^The NNN value must be between 1 and the [sqlite3_limit()]
4262** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766).
4263**
4264** ^The third argument is the value to bind to the parameter.
4265** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4266** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
4267** is ignored and the end result is the same as sqlite3_bind_null().
4268** ^If the third parameter to sqlite3_bind_text() is not NULL, then
4269** it should be a pointer to well-formed UTF8 text.
4270** ^If the third parameter to sqlite3_bind_text16() is not NULL, then
4271** it should be a pointer to well-formed UTF16 text.
4272** ^If the third parameter to sqlite3_bind_text64() is not NULL, then
4273** it should be a pointer to a well-formed unicode string that is
4274** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16
4275** otherwise.
4276**
4277** [[byte-order determination rules]] ^The byte-order of
4278** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF)
4279** found in first character, which is removed, or in the absence of a BOM
4280** the byte order is the native byte order of the host
4281** machine for sqlite3_bind_text16() or the byte order specified in
4282** the 6th parameter for sqlite3_bind_text64().)^
4283** ^If UTF16 input text contains invalid unicode
4284** characters, then SQLite might change those invalid characters
4285** into the unicode replacement character: U+FFFD.
4286**
4287** ^(In those routines that have a fourth argument, its value is the
4288** number of bytes in the parameter. To be clear: the value is the
4289** number of <u>bytes</u> in the value, not the number of characters.)^
4290** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4291** is negative, then the length of the string is
4292** the number of bytes up to the first zero terminator.
4293** If the fourth parameter to sqlite3_bind_blob() is negative, then
4294** the behavior is undefined.
4295** If a non-negative fourth parameter is provided to sqlite3_bind_text()
4296** or sqlite3_bind_text16() or sqlite3_bind_text64() then
4297** that parameter must be the byte offset
4298** where the NUL terminator would occur assuming the string were NUL
4299** terminated. If any NUL characters occurs at byte offsets less than
4300** the value of the fourth parameter then the resulting string value will
4301** contain embedded NULs. The result of expressions involving strings
4302** with embedded NULs is undefined.
4303**
4304** ^The fifth argument to the BLOB and string binding interfaces controls
4305** or indicates the lifetime of the object referenced by the third parameter.
4306** These three options exist:
4307** ^ (1) A destructor to dispose of the BLOB or string after SQLite has finished
4308** with it may be passed. ^It is called to dispose of the BLOB or string even
4309** if the call to the bind API fails, except the destructor is not called if
4310** the third parameter is a NULL pointer or the fourth parameter is negative.
4311** ^ (2) The special constant, [SQLITE_STATIC], may be passsed to indicate that
4312** the application remains responsible for disposing of the object. ^In this
4313** case, the object and the provided pointer to it must remain valid until
4314** either the prepared statement is finalized or the same SQL parameter is
4315** bound to something else, whichever occurs sooner.
4316** ^ (3) The constant, [SQLITE_TRANSIENT], may be passed to indicate that the
4317** object is to be copied prior to the return from sqlite3_bind_*(). ^The
4318** object and pointer to it must remain valid until then. ^SQLite will then
4319** manage the lifetime of its private copy.
4320**
4321** ^The sixth argument to sqlite3_bind_text64() must be one of
4322** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
4323** to specify the encoding of the text in the third parameter. If
4324** the sixth argument to sqlite3_bind_text64() is not one of the
4325** allowed values shown above, or if the text encoding is different
4326** from the encoding specified by the sixth parameter, then the behavior
4327** is undefined.
4328**
4329** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
4330** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
4331** (just an integer to hold its size) while it is being processed.
4332** Zeroblobs are intended to serve as placeholders for BLOBs whose
4333** content is later written using
4334** [sqlite3_blob_open | incremental BLOB I/O] routines.
4335** ^A negative value for the zeroblob results in a zero-length BLOB.
4336**
4337** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
4338** [prepared statement] S to have an SQL value of NULL, but to also be
4339** associated with the pointer P of type T. ^D is either a NULL pointer or
4340** a pointer to a destructor function for P. ^SQLite will invoke the
4341** destructor D with a single argument of P when it is finished using
4342** P. The T parameter should be a static string, preferably a string
4343** literal. The sqlite3_bind_pointer() routine is part of the
4344** [pointer passing interface] added for SQLite 3.20.0.
4345**
4346** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
4347** for the [prepared statement] or with a prepared statement for which
4348** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
4349** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
4350** routine is passed a [prepared statement] that has been finalized, the
4351** result is undefined and probably harmful.
4352**
4353** ^Bindings are not cleared by the [sqlite3_reset()] routine.
4354** ^Unbound parameters are interpreted as NULL.
4355**
4356** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
4357** [error code] if anything goes wrong.
4358** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
4359** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
4360** [SQLITE_MAX_LENGTH].
4361** ^[SQLITE_RANGE] is returned if the parameter
4362** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
4363**
4364** See also: [sqlite3_bind_parameter_count()],
4365** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
4366*/
4367
4368/*
4369** CAPI3REF: Number Of SQL Parameters
4370** METHOD: sqlite3_stmt
4371**
4372** ^This routine can be used to find the number of [SQL parameters]
4373** in a [prepared statement]. SQL parameters are tokens of the
4374** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
4375** placeholders for values that are [sqlite3_bind_blob | bound]
4376** to the parameters at a later time.
4377**
4378** ^(This routine actually returns the index of the largest (rightmost)
4379** parameter. For all forms except ?NNN, this will correspond to the
4380** number of unique parameters. If parameters of the ?NNN form are used,
4381** there may be gaps in the list.)^
4382**
4383** See also: [sqlite3_bind_blob|sqlite3_bind()],
4384** [sqlite3_bind_parameter_name()], and
4385** [sqlite3_bind_parameter_index()].
4386*/
4387
4388/*
4389** CAPI3REF: Name Of A Host Parameter
4390** METHOD: sqlite3_stmt
4391**
4392** ^The sqlite3_bind_parameter_name(P,N) interface returns
4393** the name of the N-th [SQL parameter] in the [prepared statement] P.
4394** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
4395** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
4396** respectively.
4397** In other words, the initial ":" or "$" or "@" or "?"
4398** is included as part of the name.)^
4399** ^Parameters of the form "?" without a following integer have no name
4400** and are referred to as "nameless" or "anonymous parameters".
4401**
4402** ^The first host parameter has an index of 1, not 0.
4403**
4404** ^If the value N is out of range or if the N-th parameter is
4405** nameless, then NULL is returned. ^The returned string is
4406** always in UTF-8 encoding even if the named parameter was
4407** originally specified as UTF-16 in [sqlite3_prepare16()],
4408** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4409**
4410** See also: [sqlite3_bind_blob|sqlite3_bind()],
4411** [sqlite3_bind_parameter_count()], and
4412** [sqlite3_bind_parameter_index()].
4413*/
4414
4415/*
4416** CAPI3REF: Index Of A Parameter With A Given Name
4417** METHOD: sqlite3_stmt
4418**
4419** ^Return the index of an SQL parameter given its name. ^The
4420** index value returned is suitable for use as the second
4421** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
4422** is returned if no matching parameter is found. ^The parameter
4423** name must be given in UTF-8 even if the original statement
4424** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
4425** [sqlite3_prepare16_v3()].
4426**
4427** See also: [sqlite3_bind_blob|sqlite3_bind()],
4428** [sqlite3_bind_parameter_count()], and
4429** [sqlite3_bind_parameter_name()].
4430*/
4431
4432/*
4433** CAPI3REF: Reset All Bindings On A Prepared Statement
4434** METHOD: sqlite3_stmt
4435**
4436** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
4437** the [sqlite3_bind_blob | bindings] on a [prepared statement].
4438** ^Use this routine to reset all host parameters to NULL.
4439*/
4440
4441/*
4442** CAPI3REF: Number Of Columns In A Result Set
4443** METHOD: sqlite3_stmt
4444**
4445** ^Return the number of columns in the result set returned by the
4446** [prepared statement]. ^If this routine returns 0, that means the
4447** [prepared statement] returns no data (for example an [UPDATE]).
4448** ^However, just because this routine returns a positive number does not
4449** mean that one or more rows of data will be returned. ^A SELECT statement
4450** will always have a positive sqlite3_column_count() but depending on the
4451** WHERE clause constraints and the table content, it might return no rows.
4452**
4453** See also: [sqlite3_data_count()]
4454*/
4455
4456/*
4457** CAPI3REF: Column Names In A Result Set
4458** METHOD: sqlite3_stmt
4459**
4460** ^These routines return the name assigned to a particular column
4461** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
4462** interface returns a pointer to a zero-terminated UTF-8 string
4463** and sqlite3_column_name16() returns a pointer to a zero-terminated
4464** UTF-16 string. ^The first parameter is the [prepared statement]
4465** that implements the [SELECT] statement. ^The second parameter is the
4466** column number. ^The leftmost column is number 0.
4467**
4468** ^The returned string pointer is valid until either the [prepared statement]
4469** is destroyed by [sqlite3_finalize()] or until the statement is automatically
4470** reprepared by the first call to [sqlite3_step()] for a particular run
4471** or until the next call to
4472** sqlite3_column_name() or sqlite3_column_name16() on the same column.
4473**
4474** ^If sqlite3_malloc() fails during the processing of either routine
4475** (for example during a conversion from UTF-8 to UTF-16) then a
4476** NULL pointer is returned.
4477**
4478** ^The name of a result column is the value of the "AS" clause for
4479** that column, if there is an AS clause. If there is no AS clause
4480** then the name of the column is unspecified and may change from
4481** one release of SQLite to the next.
4482*/
4483
4484/*
4485** CAPI3REF: Source Of Data In A Query Result
4486** METHOD: sqlite3_stmt
4487**
4488** ^These routines provide a means to determine the database, table, and
4489** table column that is the origin of a particular result column in
4490** [SELECT] statement.
4491** ^The name of the database or table or column can be returned as
4492** either a UTF-8 or UTF-16 string. ^The _database_ routines return
4493** the database name, the _table_ routines return the table name, and
4494** the origin_ routines return the column name.
4495** ^The returned string is valid until the [prepared statement] is destroyed
4496** using [sqlite3_finalize()] or until the statement is automatically
4497** reprepared by the first call to [sqlite3_step()] for a particular run
4498** or until the same information is requested
4499** again in a different encoding.
4500**
4501** ^The names returned are the original un-aliased names of the
4502** database, table, and column.
4503**
4504** ^The first argument to these interfaces is a [prepared statement].
4505** ^These functions return information about the Nth result column returned by
4506** the statement, where N is the second function argument.
4507** ^The left-most column is column 0 for these routines.
4508**
4509** ^If the Nth column returned by the statement is an expression or
4510** subquery and is not a column value, then all of these functions return
4511** NULL. ^These routines might also return NULL if a memory allocation error
4512** occurs. ^Otherwise, they return the name of the attached database, table,
4513** or column that query result column was extracted from.
4514**
4515** ^As with all other SQLite APIs, those whose names end with "16" return
4516** UTF-16 encoded strings and the other functions return UTF-8.
4517**
4518** ^These APIs are only available if the library was compiled with the
4519** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
4520**
4521** If two or more threads call one or more
4522** [sqlite3_column_database_name | column metadata interfaces]
4523** for the same [prepared statement] and result column
4524** at the same time then the results are undefined.
4525*/
4526
4527/*
4528** CAPI3REF: Declared Datatype Of A Query Result
4529** METHOD: sqlite3_stmt
4530**
4531** ^(The first parameter is a [prepared statement].
4532** If this statement is a [SELECT] statement and the Nth column of the
4533** returned result set of that [SELECT] is a table column (not an
4534** expression or subquery) then the declared type of the table
4535** column is returned.)^ ^If the Nth column of the result set is an
4536** expression or subquery, then a NULL pointer is returned.
4537** ^The returned string is always UTF-8 encoded.
4538**
4539** ^(For example, given the database schema:
4540**
4541** CREATE TABLE t1(c1 VARIANT);
4542**
4543** and the following statement to be compiled:
4544**
4545** SELECT c1 + 1, c1 FROM t1;
4546**
4547** this routine would return the string "VARIANT" for the second result
4548** column (i==1), and a NULL pointer for the first result column (i==0).)^
4549**
4550** ^SQLite uses dynamic run-time typing. ^So just because a column
4551** is declared to contain a particular type does not mean that the
4552** data stored in that column is of the declared type. SQLite is
4553** strongly typed, but the typing is dynamic not static. ^Type
4554** is associated with individual values, not with the containers
4555** used to hold those values.
4556*/
4557
4558/*
4559** CAPI3REF: Evaluate An SQL Statement
4560** METHOD: sqlite3_stmt
4561**
4562** After a [prepared statement] has been prepared using any of
4563** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
4564** or [sqlite3_prepare16_v3()] or one of the legacy
4565** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
4566** must be called one or more times to evaluate the statement.
4567**
4568** The details of the behavior of the sqlite3_step() interface depend
4569** on whether the statement was prepared using the newer "vX" interfaces
4570** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
4571** [sqlite3_prepare16_v2()] or the older legacy
4572** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
4573** new "vX" interface is recommended for new applications but the legacy
4574** interface will continue to be supported.
4575**
4576** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
4577** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
4578** ^With the "v2" interface, any of the other [result codes] or
4579** [extended result codes] might be returned as well.
4580**
4581** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
4582** database locks it needs to do its job. ^If the statement is a [COMMIT]
4583** or occurs outside of an explicit transaction, then you can retry the
4584** statement. If the statement is not a [COMMIT] and occurs within an
4585** explicit transaction then you should rollback the transaction before
4586** continuing.
4587**
4588** ^[SQLITE_DONE] means that the statement has finished executing
4589** successfully. sqlite3_step() should not be called again on this virtual
4590** machine without first calling [sqlite3_reset()] to reset the virtual
4591** machine back to its initial state.
4592**
4593** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
4594** is returned each time a new row of data is ready for processing by the
4595** caller. The values may be accessed using the [column access functions].
4596** sqlite3_step() is called again to retrieve the next row of data.
4597**
4598** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
4599** violation) has occurred. sqlite3_step() should not be called again on
4600** the VM. More information may be found by calling [sqlite3_errmsg()].
4601** ^With the legacy interface, a more specific error code (for example,
4602** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
4603** can be obtained by calling [sqlite3_reset()] on the
4604** [prepared statement]. ^In the "v2" interface,
4605** the more specific error code is returned directly by sqlite3_step().
4606**
4607** [SQLITE_MISUSE] means that the this routine was called inappropriately.
4608** Perhaps it was called on a [prepared statement] that has
4609** already been [sqlite3_finalize | finalized] or on one that had
4610** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
4611** be the case that the same database connection is being used by two or
4612** more threads at the same moment in time.
4613**
4614** For all versions of SQLite up to and including 3.6.23.1, a call to
4615** [sqlite3_reset()] was required after sqlite3_step() returned anything
4616** other than [SQLITE_ROW] before any subsequent invocation of
4617** sqlite3_step(). Failure to reset the prepared statement using
4618** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
4619** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1],
4620** sqlite3_step() began
4621** calling [sqlite3_reset()] automatically in this circumstance rather
4622** than returning [SQLITE_MISUSE]. This is not considered a compatibility
4623** break because any application that ever receives an SQLITE_MISUSE error
4624** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
4625** can be used to restore the legacy behavior.
4626**
4627** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
4628** API always returns a generic error code, [SQLITE_ERROR], following any
4629** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
4630** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
4631** specific [error codes] that better describes the error.
4632** We admit that this is a goofy design. The problem has been fixed
4633** with the "v2" interface. If you prepare all of your SQL statements
4634** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
4635** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
4636** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
4637** then the more specific [error codes] are returned directly
4638** by sqlite3_step(). The use of the "vX" interfaces is recommended.
4639*/
4640
4641/*
4642** CAPI3REF: Number of columns in a result set
4643** METHOD: sqlite3_stmt
4644**
4645** ^The sqlite3_data_count(P) interface returns the number of columns in the
4646** current row of the result set of [prepared statement] P.
4647** ^If prepared statement P does not have results ready to return
4648** (via calls to the [sqlite3_column_int | sqlite3_column()] family of
4649** interfaces) then sqlite3_data_count(P) returns 0.
4650** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
4651** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
4652** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
4653** will return non-zero if previous call to [sqlite3_step](P) returned
4654** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
4655** where it always returns zero since each step of that multi-step
4656** pragma returns 0 columns of data.
4657**
4658** See also: [sqlite3_column_count()]
4659*/
4660
4661/*
4662** CAPI3REF: Fundamental Datatypes
4663** KEYWORDS: SQLITE_TEXT
4664**
4665** ^(Every value in SQLite has one of five fundamental datatypes:
4666**
4667** <ul>
4668** <li> 64-bit signed integer
4669** <li> 64-bit IEEE floating point number
4670** <li> string
4671** <li> BLOB
4672** <li> NULL
4673** </ul>)^
4674**
4675** These constants are codes for each of those types.
4676**
4677** Note that the SQLITE_TEXT constant was also used in SQLite version 2
4678** for a completely different meaning. Software that links against both
4679** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
4680** SQLITE_TEXT.
4681*/
4682#define SQLITE_INTEGER 1
4683#define SQLITE_FLOAT 2
4684#define SQLITE_BLOB 4
4685#define SQLITE_NULL 5
4686#ifdef SQLITE_TEXT
4687# undef SQLITE_TEXT
4688#else
4689# define SQLITE_TEXT 3
4690#endif
4691#define SQLITE3_TEXT 3
4692
4693/*
4694** CAPI3REF: Result Values From A Query
4695** KEYWORDS: {column access functions}
4696** METHOD: sqlite3_stmt
4697**
4698** <b>Summary:</b>
4699** <blockquote><table border=0 cellpadding=0 cellspacing=0>
4700** <tr><td><b>sqlite3_column_blob</b><td>&rarr;<td>BLOB result
4701** <tr><td><b>sqlite3_column_double</b><td>&rarr;<td>REAL result
4702** <tr><td><b>sqlite3_column_int</b><td>&rarr;<td>32-bit INTEGER result
4703** <tr><td><b>sqlite3_column_int64</b><td>&rarr;<td>64-bit INTEGER result
4704** <tr><td><b>sqlite3_column_text</b><td>&rarr;<td>UTF-8 TEXT result
4705** <tr><td><b>sqlite3_column_text16</b><td>&rarr;<td>UTF-16 TEXT result
4706** <tr><td><b>sqlite3_column_value</b><td>&rarr;<td>The result as an
4707** [sqlite3_value|unprotected sqlite3_value] object.
4708** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
4709** <tr><td><b>sqlite3_column_bytes</b><td>&rarr;<td>Size of a BLOB
4710** or a UTF-8 TEXT result in bytes
4711** <tr><td><b>sqlite3_column_bytes16&nbsp;&nbsp;</b>
4712** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
4713** TEXT in bytes
4714** <tr><td><b>sqlite3_column_type</b><td>&rarr;<td>Default
4715** datatype of the result
4716** </table></blockquote>
4717**
4718** <b>Details:</b>
4719**
4720** ^These routines return information about a single column of the current
4721** result row of a query. ^In every case the first argument is a pointer
4722** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
4723** that was returned from [sqlite3_prepare_v2()] or one of its variants)
4724** and the second argument is the index of the column for which information
4725** should be returned. ^The leftmost column of the result set has the index 0.
4726** ^The number of columns in the result can be determined using
4727** [sqlite3_column_count()].
4728**
4729** If the SQL statement does not currently point to a valid row, or if the
4730** column index is out of range, the result is undefined.
4731** These routines may only be called when the most recent call to
4732** [sqlite3_step()] has returned [SQLITE_ROW] and neither
4733** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
4734** If any of these routines are called after [sqlite3_reset()] or
4735** [sqlite3_finalize()] or after [sqlite3_step()] has returned
4736** something other than [SQLITE_ROW], the results are undefined.
4737** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
4738** are called from a different thread while any of these routines
4739** are pending, then the results are undefined.
4740**
4741** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
4742** each return the value of a result column in a specific data format. If
4743** the result column is not initially in the requested format (for example,
4744** if the query returns an integer but the sqlite3_column_text() interface
4745** is used to extract the value) then an automatic type conversion is performed.
4746**
4747** ^The sqlite3_column_type() routine returns the
4748** [SQLITE_INTEGER | datatype code] for the initial data type
4749** of the result column. ^The returned value is one of [SQLITE_INTEGER],
4750** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
4751** The return value of sqlite3_column_type() can be used to decide which
4752** of the first six interface should be used to extract the column value.
4753** The value returned by sqlite3_column_type() is only meaningful if no
4754** automatic type conversions have occurred for the value in question.
4755** After a type conversion, the result of calling sqlite3_column_type()
4756** is undefined, though harmless. Future
4757** versions of SQLite may change the behavior of sqlite3_column_type()
4758** following a type conversion.
4759**
4760** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
4761** or sqlite3_column_bytes16() interfaces can be used to determine the size
4762** of that BLOB or string.
4763**
4764** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
4765** routine returns the number of bytes in that BLOB or string.
4766** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
4767** the string to UTF-8 and then returns the number of bytes.
4768** ^If the result is a numeric value then sqlite3_column_bytes() uses
4769** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
4770** the number of bytes in that string.
4771** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
4772**
4773** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
4774** routine returns the number of bytes in that BLOB or string.
4775** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
4776** the string to UTF-16 and then returns the number of bytes.
4777** ^If the result is a numeric value then sqlite3_column_bytes16() uses
4778** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
4779** the number of bytes in that string.
4780** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
4781**
4782** ^The values returned by [sqlite3_column_bytes()] and
4783** [sqlite3_column_bytes16()] do not include the zero terminators at the end
4784** of the string. ^For clarity: the values returned by
4785** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
4786** bytes in the string, not the number of characters.
4787**
4788** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
4789** even empty strings, are always zero-terminated. ^The return
4790** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
4791**
4792** ^Strings returned by sqlite3_column_text16() always have the endianness
4793** which is native to the platform, regardless of the text encoding set
4794** for the database.
4795**
4796** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
4797** [unprotected sqlite3_value] object. In a multithreaded environment,
4798** an unprotected sqlite3_value object may only be used safely with
4799** [sqlite3_bind_value()] and [sqlite3_result_value()].
4800** If the [unprotected sqlite3_value] object returned by
4801** [sqlite3_column_value()] is used in any other way, including calls
4802** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
4803** or [sqlite3_value_bytes()], the behavior is not threadsafe.
4804** Hence, the sqlite3_column_value() interface
4805** is normally only useful within the implementation of
4806** [application-defined SQL functions] or [virtual tables], not within
4807** top-level application code.
4808**
4809** These routines may attempt to convert the datatype of the result.
4810** ^For example, if the internal representation is FLOAT and a text result
4811** is requested, [sqlite3_snprintf()] is used internally to perform the
4812** conversion automatically. ^(The following table details the conversions
4813** that are applied:
4814**
4815** <blockquote>
4816** <table border="1">
4817** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
4818**
4819** <tr><td> NULL <td> INTEGER <td> Result is 0
4820** <tr><td> NULL <td> FLOAT <td> Result is 0.0
4821** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer
4822** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer
4823** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
4824** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
4825** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
4826** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER
4827** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
4828** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB
4829** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER
4830** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL
4831** <tr><td> TEXT <td> BLOB <td> No change
4832** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER
4833** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL
4834** <tr><td> BLOB <td> TEXT <td> [CAST] to TEXT, ensure zero terminator
4835** </table>
4836** </blockquote>)^
4837**
4838** Note that when type conversions occur, pointers returned by prior
4839** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
4840** sqlite3_column_text16() may be invalidated.
4841** Type conversions and pointer invalidations might occur
4842** in the following cases:
4843**
4844** <ul>
4845** <li> The initial content is a BLOB and sqlite3_column_text() or
4846** sqlite3_column_text16() is called. A zero-terminator might
4847** need to be added to the string.</li>
4848** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
4849** sqlite3_column_text16() is called. The content must be converted
4850** to UTF-16.</li>
4851** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
4852** sqlite3_column_text() is called. The content must be converted
4853** to UTF-8.</li>
4854** </ul>
4855**
4856** ^Conversions between UTF-16be and UTF-16le are always done in place and do
4857** not invalidate a prior pointer, though of course the content of the buffer
4858** that the prior pointer references will have been modified. Other kinds
4859** of conversion are done in place when it is possible, but sometimes they
4860** are not possible and in those cases prior pointers are invalidated.
4861**
4862** The safest policy is to invoke these routines
4863** in one of the following ways:
4864**
4865** <ul>
4866** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
4867** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
4868** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
4869** </ul>
4870**
4871** In other words, you should call sqlite3_column_text(),
4872** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
4873** into the desired format, then invoke sqlite3_column_bytes() or
4874** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
4875** to sqlite3_column_text() or sqlite3_column_blob() with calls to
4876** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
4877** with calls to sqlite3_column_bytes().
4878**
4879** ^The pointers returned are valid until a type conversion occurs as
4880** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
4881** [sqlite3_finalize()] is called. ^The memory space used to hold strings
4882** and BLOBs is freed automatically. Do not pass the pointers returned
4883** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
4884** [sqlite3_free()].
4885**
4886** As long as the input parameters are correct, these routines will only
4887** fail if an out-of-memory error occurs during a format conversion.
4888** Only the following subset of interfaces are subject to out-of-memory
4889** errors:
4890**
4891** <ul>
4892** <li> sqlite3_column_blob()
4893** <li> sqlite3_column_text()
4894** <li> sqlite3_column_text16()
4895** <li> sqlite3_column_bytes()
4896** <li> sqlite3_column_bytes16()
4897** </ul>
4898**
4899** If an out-of-memory error occurs, then the return value from these
4900** routines is the same as if the column had contained an SQL NULL value.
4901** Valid SQL NULL returns can be distinguished from out-of-memory errors
4902** by invoking the [sqlite3_errcode()] immediately after the suspect
4903** return value is obtained and before any
4904** other SQLite interface is called on the same [database connection].
4905*/
4906
4907/*
4908** CAPI3REF: Destroy A Prepared Statement Object
4909** DESTRUCTOR: sqlite3_stmt
4910**
4911** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4912** ^If the most recent evaluation of the statement encountered no errors
4913** or if the statement is never been evaluated, then sqlite3_finalize() returns
4914** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
4915** sqlite3_finalize(S) returns the appropriate [error code] or
4916** [extended error code].
4917**
4918** ^The sqlite3_finalize(S) routine can be called at any point during
4919** the life cycle of [prepared statement] S:
4920** before statement S is ever evaluated, after
4921** one or more calls to [sqlite3_reset()], or after any call
4922** to [sqlite3_step()] regardless of whether or not the statement has
4923** completed execution.
4924**
4925** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4926**
4927** The application must finalize every [prepared statement] in order to avoid
4928** resource leaks. It is a grievous error for the application to try to use
4929** a prepared statement after it has been finalized. Any use of a prepared
4930** statement after it has been finalized can result in undefined and
4931** undesirable behavior such as segfaults and heap corruption.
4932*/
4933
4934/*
4935** CAPI3REF: Reset A Prepared Statement Object
4936** METHOD: sqlite3_stmt
4937**
4938** The sqlite3_reset() function is called to reset a [prepared statement]
4939** object back to its initial state, ready to be re-executed.
4940** ^Any SQL statement variables that had values bound to them using
4941** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4942** Use [sqlite3_clear_bindings()] to reset the bindings.
4943**
4944** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4945** back to the beginning of its program.
4946**
4947** ^If the most recent call to [sqlite3_step(S)] for the
4948** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4949** or if [sqlite3_step(S)] has never before been called on S,
4950** then [sqlite3_reset(S)] returns [SQLITE_OK].
4951**
4952** ^If the most recent call to [sqlite3_step(S)] for the
4953** [prepared statement] S indicated an error, then
4954** [sqlite3_reset(S)] returns an appropriate [error code].
4955**
4956** ^The [sqlite3_reset(S)] interface does not change the values
4957** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4958*/
4959
4960/*
4961** CAPI3REF: Create Or Redefine SQL Functions
4962** KEYWORDS: {function creation routines}
4963** METHOD: sqlite3
4964**
4965** ^These functions (collectively known as "function creation routines")
4966** are used to add SQL functions or aggregates or to redefine the behavior
4967** of existing SQL functions or aggregates. The only differences between
4968** the three "sqlite3_create_function*" routines are the text encoding
4969** expected for the second parameter (the name of the function being
4970** created) and the presence or absence of a destructor callback for
4971** the application data pointer. Function sqlite3_create_window_function()
4972** is similar, but allows the user to supply the extra callback functions
4973** needed by [aggregate window functions].
4974**
4975** ^The first parameter is the [database connection] to which the SQL
4976** function is to be added. ^If an application uses more than one database
4977** connection then application-defined SQL functions must be added
4978** to each database connection separately.
4979**
4980** ^The second parameter is the name of the SQL function to be created or
4981** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
4982** representation, exclusive of the zero-terminator. ^Note that the name
4983** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4984** ^Any attempt to create a function with a longer name
4985** will result in [SQLITE_MISUSE] being returned.
4986**
4987** ^The third parameter (nArg)
4988** is the number of arguments that the SQL function or
4989** aggregate takes. ^If this parameter is -1, then the SQL function or
4990** aggregate may take any number of arguments between 0 and the limit
4991** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
4992** parameter is less than -1 or greater than 127 then the behavior is
4993** undefined.
4994**
4995** ^The fourth parameter, eTextRep, specifies what
4996** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4997** its parameters. The application should set this parameter to
4998** [SQLITE_UTF16LE] if the function implementation invokes
4999** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
5000** implementation invokes [sqlite3_value_text16be()] on an input, or
5001** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
5002** otherwise. ^The same SQL function may be registered multiple times using
5003** different preferred text encodings, with different implementations for
5004** each encoding.
5005** ^When multiple implementations of the same function are available, SQLite
5006** will pick the one that involves the least amount of data conversion.
5007**
5008** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
5009** to signal that the function will always return the same result given
5010** the same inputs within a single SQL statement. Most SQL functions are
5011** deterministic. The built-in [random()] SQL function is an example of a
5012** function that is not deterministic. The SQLite query planner is able to
5013** perform additional optimizations on deterministic functions, so use
5014** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
5015**
5016** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY]
5017** flag, which if present prevents the function from being invoked from
5018** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions,
5019** index expressions, or the WHERE clause of partial indexes.
5020**
5021** For best security, the [SQLITE_DIRECTONLY] flag is recommended for
5022** all application-defined SQL functions that do not need to be
5023** used inside of triggers, view, CHECK constraints, or other elements of
5024** the database schema. This flags is especially recommended for SQL
5025** functions that have side effects or reveal internal application state.
5026** Without this flag, an attacker might be able to modify the schema of
5027** a database file to include invocations of the function with parameters
5028** chosen by the attacker, which the application will then execute when
5029** the database file is opened and read.
5030**
5031** ^(The fifth parameter is an arbitrary pointer. The implementation of the
5032** function can gain access to this pointer using [sqlite3_user_data()].)^
5033**
5034** ^The sixth, seventh and eighth parameters passed to the three
5035** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
5036** pointers to C-language functions that implement the SQL function or
5037** aggregate. ^A scalar SQL function requires an implementation of the xFunc
5038** callback only; NULL pointers must be passed as the xStep and xFinal
5039** parameters. ^An aggregate SQL function requires an implementation of xStep
5040** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
5041** SQL function or aggregate, pass NULL pointers for all three function
5042** callbacks.
5043**
5044** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
5045** and xInverse) passed to sqlite3_create_window_function are pointers to
5046** C-language callbacks that implement the new function. xStep and xFinal
5047** must both be non-NULL. xValue and xInverse may either both be NULL, in
5048** which case a regular aggregate function is created, or must both be
5049** non-NULL, in which case the new function may be used as either an aggregate
5050** or aggregate window function. More details regarding the implementation
5051** of aggregate window functions are
5052** [user-defined window functions|available here].
5053**
5054** ^(If the final parameter to sqlite3_create_function_v2() or
5055** sqlite3_create_window_function() is not NULL, then it is destructor for
5056** the application data pointer. The destructor is invoked when the function
5057** is deleted, either by being overloaded or when the database connection
5058** closes.)^ ^The destructor is also invoked if the call to
5059** sqlite3_create_function_v2() fails. ^When the destructor callback is
5060** invoked, it is passed a single argument which is a copy of the application
5061** data pointer which was the fifth parameter to sqlite3_create_function_v2().
5062**
5063** ^It is permitted to register multiple implementations of the same
5064** functions with the same name but with either differing numbers of
5065** arguments or differing preferred text encodings. ^SQLite will use
5066** the implementation that most closely matches the way in which the
5067** SQL function is used. ^A function implementation with a non-negative
5068** nArg parameter is a better match than a function implementation with
5069** a negative nArg. ^A function where the preferred text encoding
5070** matches the database encoding is a better
5071** match than a function where the encoding is different.
5072** ^A function where the encoding difference is between UTF16le and UTF16be
5073** is a closer match than a function where the encoding difference is
5074** between UTF8 and UTF16.
5075**
5076** ^Built-in functions may be overloaded by new application-defined functions.
5077**
5078** ^An application-defined function is permitted to call other
5079** SQLite interfaces. However, such calls must not
5080** close the database connection nor finalize or reset the prepared
5081** statement in which the function is running.
5082*/
5083
5084/*
5085** CAPI3REF: Text Encodings
5086**
5087** These constant define integer codes that represent the various
5088** text encodings supported by SQLite.
5089*/
5090#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */
5091#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */
5092#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */
5093#define SQLITE_UTF16 4 /* Use native byte order */
5094#define SQLITE_ANY 5 /* Deprecated */
5095#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
5096
5097/*
5098** CAPI3REF: Function Flags
5099**
5100** These constants may be ORed together with the
5101** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
5102** to [sqlite3_create_function()], [sqlite3_create_function16()], or
5103** [sqlite3_create_function_v2()].
5104**
5105** <dl>
5106** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd>
5107** The SQLITE_DETERMINISTIC flag means that the new function always gives
5108** the same output when the input parameters are the same.
5109** The [abs|abs() function] is deterministic, for example, but
5110** [randomblob|randomblob()] is not. Functions must
5111** be deterministic in order to be used in certain contexts such as
5112** with the WHERE clause of [partial indexes] or in [generated columns].
5113** SQLite might also optimize deterministic functions by factoring them
5114** out of inner loops.
5115** </dd>
5116**
5117** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd>
5118** The SQLITE_DIRECTONLY flag means that the function may only be invoked
5119** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in
5120** schema structures such as [CHECK constraints], [DEFAULT clauses],
5121** [expression indexes], [partial indexes], or [generated columns].
5122** The SQLITE_DIRECTONLY flags is a security feature which is recommended
5123** for all [application-defined SQL functions], and especially for functions
5124** that have side-effects or that could potentially leak sensitive
5125** information.
5126** </dd>
5127**
5128** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd>
5129** The SQLITE_INNOCUOUS flag means that the function is unlikely
5130** to cause problems even if misused. An innocuous function should have
5131** no side effects and should not depend on any values other than its
5132** input parameters. The [abs|abs() function] is an example of an
5133** innocuous function.
5134** The [load_extension() SQL function] is not innocuous because of its
5135** side effects.
5136** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not
5137** exactly the same. The [random|random() function] is an example of a
5138** function that is innocuous but not deterministic.
5139** <p>Some heightened security settings
5140** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF])
5141** disable the use of SQL functions inside views and triggers and in
5142** schema structures such as [CHECK constraints], [DEFAULT clauses],
5143** [expression indexes], [partial indexes], and [generated columns] unless
5144** the function is tagged with SQLITE_INNOCUOUS. Most built-in functions
5145** are innocuous. Developers are advised to avoid using the
5146** SQLITE_INNOCUOUS flag for application-defined functions unless the
5147** function has been carefully audited and found to be free of potentially
5148** security-adverse side-effects and information-leaks.
5149** </dd>
5150**
5151** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd>
5152** The SQLITE_SUBTYPE flag indicates to SQLite that a function may call
5153** [sqlite3_value_subtype()] to inspect the sub-types of its arguments.
5154** Specifying this flag makes no difference for scalar or aggregate user
5155** functions. However, if it is not specified for a user-defined window
5156** function, then any sub-types belonging to arguments passed to the window
5157** function may be discarded before the window function is called (i.e.
5158** sqlite3_value_subtype() will always return 0).
5159** </dd>
5160** </dl>
5161*/
5162#define SQLITE_DETERMINISTIC 0x000000800
5163#define SQLITE_DIRECTONLY 0x000080000
5164#define SQLITE_SUBTYPE 0x000100000
5165#define SQLITE_INNOCUOUS 0x000200000
5166
5167/*
5168** CAPI3REF: Deprecated Functions
5169** DEPRECATED
5170**
5171** These functions are [deprecated]. In order to maintain
5172** backwards compatibility with older code, these functions continue
5173** to be supported. However, new applications should avoid
5174** the use of these functions. To encourage programmers to avoid
5175** these functions, we will not explain what they do.
5176*/
5177#ifndef SQLITE_OMIT_DEPRECATED
5178#endif
5179
5180/*
5181** CAPI3REF: Obtaining SQL Values
5182** METHOD: sqlite3_value
5183**
5184** <b>Summary:</b>
5185** <blockquote><table border=0 cellpadding=0 cellspacing=0>
5186** <tr><td><b>sqlite3_value_blob</b><td>&rarr;<td>BLOB value
5187** <tr><td><b>sqlite3_value_double</b><td>&rarr;<td>REAL value
5188** <tr><td><b>sqlite3_value_int</b><td>&rarr;<td>32-bit INTEGER value
5189** <tr><td><b>sqlite3_value_int64</b><td>&rarr;<td>64-bit INTEGER value
5190** <tr><td><b>sqlite3_value_pointer</b><td>&rarr;<td>Pointer value
5191** <tr><td><b>sqlite3_value_text</b><td>&rarr;<td>UTF-8 TEXT value
5192** <tr><td><b>sqlite3_value_text16</b><td>&rarr;<td>UTF-16 TEXT value in
5193** the native byteorder
5194** <tr><td><b>sqlite3_value_text16be</b><td>&rarr;<td>UTF-16be TEXT value
5195** <tr><td><b>sqlite3_value_text16le</b><td>&rarr;<td>UTF-16le TEXT value
5196** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
5197** <tr><td><b>sqlite3_value_bytes</b><td>&rarr;<td>Size of a BLOB
5198** or a UTF-8 TEXT in bytes
5199** <tr><td><b>sqlite3_value_bytes16&nbsp;&nbsp;</b>
5200** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
5201** TEXT in bytes
5202** <tr><td><b>sqlite3_value_type</b><td>&rarr;<td>Default
5203** datatype of the value
5204** <tr><td><b>sqlite3_value_numeric_type&nbsp;&nbsp;</b>
5205** <td>&rarr;&nbsp;&nbsp;<td>Best numeric datatype of the value
5206** <tr><td><b>sqlite3_value_nochange&nbsp;&nbsp;</b>
5207** <td>&rarr;&nbsp;&nbsp;<td>True if the column is unchanged in an UPDATE
5208** against a virtual table.
5209** <tr><td><b>sqlite3_value_frombind&nbsp;&nbsp;</b>
5210** <td>&rarr;&nbsp;&nbsp;<td>True if value originated from a [bound parameter]
5211** </table></blockquote>
5212**
5213** <b>Details:</b>
5214**
5215** These routines extract type, size, and content information from
5216** [protected sqlite3_value] objects. Protected sqlite3_value objects
5217** are used to pass parameter information into the functions that
5218** implement [application-defined SQL functions] and [virtual tables].
5219**
5220** These routines work only with [protected sqlite3_value] objects.
5221** Any attempt to use these routines on an [unprotected sqlite3_value]
5222** is not threadsafe.
5223**
5224** ^These routines work just like the corresponding [column access functions]
5225** except that these routines take a single [protected sqlite3_value] object
5226** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
5227**
5228** ^The sqlite3_value_text16() interface extracts a UTF-16 string
5229** in the native byte-order of the host machine. ^The
5230** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
5231** extract UTF-16 strings as big-endian and little-endian respectively.
5232**
5233** ^If [sqlite3_value] object V was initialized
5234** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
5235** and if X and Y are strings that compare equal according to strcmp(X,Y),
5236** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise,
5237** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
5238** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5239**
5240** ^(The sqlite3_value_type(V) interface returns the
5241** [SQLITE_INTEGER | datatype code] for the initial datatype of the
5242** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
5243** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
5244** Other interfaces might change the datatype for an sqlite3_value object.
5245** For example, if the datatype is initially SQLITE_INTEGER and
5246** sqlite3_value_text(V) is called to extract a text value for that
5247** integer, then subsequent calls to sqlite3_value_type(V) might return
5248** SQLITE_TEXT. Whether or not a persistent internal datatype conversion
5249** occurs is undefined and may change from one release of SQLite to the next.
5250**
5251** ^(The sqlite3_value_numeric_type() interface attempts to apply
5252** numeric affinity to the value. This means that an attempt is
5253** made to convert the value to an integer or floating point. If
5254** such a conversion is possible without loss of information (in other
5255** words, if the value is a string that looks like a number)
5256** then the conversion is performed. Otherwise no conversion occurs.
5257** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
5258**
5259** ^Within the [xUpdate] method of a [virtual table], the
5260** sqlite3_value_nochange(X) interface returns true if and only if
5261** the column corresponding to X is unchanged by the UPDATE operation
5262** that the xUpdate method call was invoked to implement and if
5263** and the prior [xColumn] method call that was invoked to extracted
5264** the value for that column returned without setting a result (probably
5265** because it queried [sqlite3_vtab_nochange()] and found that the column
5266** was unchanging). ^Within an [xUpdate] method, any value for which
5267** sqlite3_value_nochange(X) is true will in all other respects appear
5268** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other
5269** than within an [xUpdate] method call for an UPDATE statement, then
5270** the return value is arbitrary and meaningless.
5271**
5272** ^The sqlite3_value_frombind(X) interface returns non-zero if the
5273** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()]
5274** interfaces. ^If X comes from an SQL literal value, or a table column,
5275** or an expression, then sqlite3_value_frombind(X) returns zero.
5276**
5277** Please pay particular attention to the fact that the pointer returned
5278** from [sqlite3_value_blob()], [sqlite3_value_text()], or
5279** [sqlite3_value_text16()] can be invalidated by a subsequent call to
5280** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
5281** or [sqlite3_value_text16()].
5282**
5283** These routines must be called from the same thread as
5284** the SQL function that supplied the [sqlite3_value*] parameters.
5285**
5286** As long as the input parameter is correct, these routines can only
5287** fail if an out-of-memory error occurs during a format conversion.
5288** Only the following subset of interfaces are subject to out-of-memory
5289** errors:
5290**
5291** <ul>
5292** <li> sqlite3_value_blob()
5293** <li> sqlite3_value_text()
5294** <li> sqlite3_value_text16()
5295** <li> sqlite3_value_text16le()
5296** <li> sqlite3_value_text16be()
5297** <li> sqlite3_value_bytes()
5298** <li> sqlite3_value_bytes16()
5299** </ul>
5300**
5301** If an out-of-memory error occurs, then the return value from these
5302** routines is the same as if the column had contained an SQL NULL value.
5303** Valid SQL NULL returns can be distinguished from out-of-memory errors
5304** by invoking the [sqlite3_errcode()] immediately after the suspect
5305** return value is obtained and before any
5306** other SQLite interface is called on the same [database connection].
5307*/
5308
5309/*
5310** CAPI3REF: Finding The Subtype Of SQL Values
5311** METHOD: sqlite3_value
5312**
5313** The sqlite3_value_subtype(V) function returns the subtype for
5314** an [application-defined SQL function] argument V. The subtype
5315** information can be used to pass a limited amount of context from
5316** one SQL function to another. Use the [sqlite3_result_subtype()]
5317** routine to set the subtype for the return value of an SQL function.
5318*/
5319
5320/*
5321** CAPI3REF: Copy And Free SQL Values
5322** METHOD: sqlite3_value
5323**
5324** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
5325** object D and returns a pointer to that copy. ^The [sqlite3_value] returned
5326** is a [protected sqlite3_value] object even if the input is not.
5327** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
5328** memory allocation fails. ^If V is a [pointer value], then the result
5329** of sqlite3_value_dup(V) is a NULL value.
5330**
5331** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
5332** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer
5333** then sqlite3_value_free(V) is a harmless no-op.
5334*/
5335
5336/*
5337** CAPI3REF: Obtain Aggregate Function Context
5338** METHOD: sqlite3_context
5339**
5340** Implementations of aggregate SQL functions use this
5341** routine to allocate memory for storing their state.
5342**
5343** ^The first time the sqlite3_aggregate_context(C,N) routine is called
5344** for a particular aggregate function, SQLite allocates
5345** N bytes of memory, zeroes out that memory, and returns a pointer
5346** to the new memory. ^On second and subsequent calls to
5347** sqlite3_aggregate_context() for the same aggregate function instance,
5348** the same buffer is returned. Sqlite3_aggregate_context() is normally
5349** called once for each invocation of the xStep callback and then one
5350** last time when the xFinal callback is invoked. ^(When no rows match
5351** an aggregate query, the xStep() callback of the aggregate function
5352** implementation is never called and xFinal() is called exactly once.
5353** In those cases, sqlite3_aggregate_context() might be called for the
5354** first time from within xFinal().)^
5355**
5356** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
5357** when first called if N is less than or equal to zero or if a memory
5358** allocate error occurs.
5359**
5360** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
5361** determined by the N parameter on first successful call. Changing the
5362** value of N in any subsequent call to sqlite3_aggregate_context() within
5363** the same aggregate function instance will not resize the memory
5364** allocation.)^ Within the xFinal callback, it is customary to set
5365** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
5366** pointless memory allocations occur.
5367**
5368** ^SQLite automatically frees the memory allocated by
5369** sqlite3_aggregate_context() when the aggregate query concludes.
5370**
5371** The first parameter must be a copy of the
5372** [sqlite3_context | SQL function context] that is the first parameter
5373** to the xStep or xFinal callback routine that implements the aggregate
5374** function.
5375**
5376** This routine must be called from the same thread in which
5377** the aggregate SQL function is running.
5378*/
5379
5380/*
5381** CAPI3REF: User Data For Functions
5382** METHOD: sqlite3_context
5383**
5384** ^The sqlite3_user_data() interface returns a copy of
5385** the pointer that was the pUserData parameter (the 5th parameter)
5386** of the [sqlite3_create_function()]
5387** and [sqlite3_create_function16()] routines that originally
5388** registered the application defined function.
5389**
5390** This routine must be called from the same thread in which
5391** the application-defined function is running.
5392*/
5393
5394/*
5395** CAPI3REF: Database Connection For Functions
5396** METHOD: sqlite3_context
5397**
5398** ^The sqlite3_context_db_handle() interface returns a copy of
5399** the pointer to the [database connection] (the 1st parameter)
5400** of the [sqlite3_create_function()]
5401** and [sqlite3_create_function16()] routines that originally
5402** registered the application defined function.
5403*/
5404
5405/*
5406** CAPI3REF: Function Auxiliary Data
5407** METHOD: sqlite3_context
5408**
5409** These functions may be used by (non-aggregate) SQL functions to
5410** associate metadata with argument values. If the same value is passed to
5411** multiple invocations of the same SQL function during query execution, under
5412** some circumstances the associated metadata may be preserved. An example
5413** of where this might be useful is in a regular-expression matching
5414** function. The compiled version of the regular expression can be stored as
5415** metadata associated with the pattern string.
5416** Then as long as the pattern string remains the same,
5417** the compiled regular expression can be reused on multiple
5418** invocations of the same function.
5419**
5420** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata
5421** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
5422** value to the application-defined function. ^N is zero for the left-most
5423** function argument. ^If there is no metadata
5424** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
5425** returns a NULL pointer.
5426**
5427** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
5428** argument of the application-defined function. ^Subsequent
5429** calls to sqlite3_get_auxdata(C,N) return P from the most recent
5430** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
5431** NULL if the metadata has been discarded.
5432** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
5433** SQLite will invoke the destructor function X with parameter P exactly
5434** once, when the metadata is discarded.
5435** SQLite is free to discard the metadata at any time, including: <ul>
5436** <li> ^(when the corresponding function parameter changes)^, or
5437** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
5438** SQL statement)^, or
5439** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
5440** parameter)^, or
5441** <li> ^(during the original sqlite3_set_auxdata() call when a memory
5442** allocation error occurs.)^ </ul>
5443**
5444** Note the last bullet in particular. The destructor X in
5445** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
5446** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
5447** should be called near the end of the function implementation and the
5448** function implementation should not make any use of P after
5449** sqlite3_set_auxdata() has been called.
5450**
5451** ^(In practice, metadata is preserved between function calls for
5452** function parameters that are compile-time constants, including literal
5453** values and [parameters] and expressions composed from the same.)^
5454**
5455** The value of the N parameter to these interfaces should be non-negative.
5456** Future enhancements may make use of negative N values to define new
5457** kinds of function caching behavior.
5458**
5459** These routines must be called from the same thread in which
5460** the SQL function is running.
5461*/
5462
5463
5464/*
5465** CAPI3REF: Constants Defining Special Destructor Behavior
5466**
5467** These are special values for the destructor that is passed in as the
5468** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
5469** argument is SQLITE_STATIC, it means that the content pointer is constant
5470** and will never change. It does not need to be destroyed. ^The
5471** SQLITE_TRANSIENT value means that the content will likely change in
5472** the near future and that SQLite should make its own private copy of
5473** the content before returning.
5474**
5475** The typedef is necessary to work around problems in certain
5476** C++ compilers.
5477*/
5478typedef void (*sqlite3_destructor_type)(void*);
5479#define SQLITE_STATIC ((sqlite3_destructor_type)0)
5480#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
5481
5482/*
5483** CAPI3REF: Setting The Result Of An SQL Function
5484** METHOD: sqlite3_context
5485**
5486** These routines are used by the xFunc or xFinal callbacks that
5487** implement SQL functions and aggregates. See
5488** [sqlite3_create_function()] and [sqlite3_create_function16()]
5489** for additional information.
5490**
5491** These functions work very much like the [parameter binding] family of
5492** functions used to bind values to host parameters in prepared statements.
5493** Refer to the [SQL parameter] documentation for additional information.
5494**
5495** ^The sqlite3_result_blob() interface sets the result from
5496** an application-defined function to be the BLOB whose content is pointed
5497** to by the second parameter and which is N bytes long where N is the
5498** third parameter.
5499**
5500** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
5501** interfaces set the result of the application-defined function to be
5502** a BLOB containing all zero bytes and N bytes in size.
5503**
5504** ^The sqlite3_result_double() interface sets the result from
5505** an application-defined function to be a floating point value specified
5506** by its 2nd argument.
5507**
5508** ^The sqlite3_result_error() and sqlite3_result_error16() functions
5509** cause the implemented SQL function to throw an exception.
5510** ^SQLite uses the string pointed to by the
5511** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
5512** as the text of an error message. ^SQLite interprets the error
5513** message string from sqlite3_result_error() as UTF-8. ^SQLite
5514** interprets the string from sqlite3_result_error16() as UTF-16 using
5515** the same [byte-order determination rules] as [sqlite3_bind_text16()].
5516** ^If the third parameter to sqlite3_result_error()
5517** or sqlite3_result_error16() is negative then SQLite takes as the error
5518** message all text up through the first zero character.
5519** ^If the third parameter to sqlite3_result_error() or
5520** sqlite3_result_error16() is non-negative then SQLite takes that many
5521** bytes (not characters) from the 2nd parameter as the error message.
5522** ^The sqlite3_result_error() and sqlite3_result_error16()
5523** routines make a private copy of the error message text before
5524** they return. Hence, the calling function can deallocate or
5525** modify the text after they return without harm.
5526** ^The sqlite3_result_error_code() function changes the error code
5527** returned by SQLite as a result of an error in a function. ^By default,
5528** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
5529** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
5530**
5531** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
5532** error indicating that a string or BLOB is too long to represent.
5533**
5534** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
5535** error indicating that a memory allocation failed.
5536**
5537** ^The sqlite3_result_int() interface sets the return value
5538** of the application-defined function to be the 32-bit signed integer
5539** value given in the 2nd argument.
5540** ^The sqlite3_result_int64() interface sets the return value
5541** of the application-defined function to be the 64-bit signed integer
5542** value given in the 2nd argument.
5543**
5544** ^The sqlite3_result_null() interface sets the return value
5545** of the application-defined function to be NULL.
5546**
5547** ^The sqlite3_result_text(), sqlite3_result_text16(),
5548** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
5549** set the return value of the application-defined function to be
5550** a text string which is represented as UTF-8, UTF-16 native byte order,
5551** UTF-16 little endian, or UTF-16 big endian, respectively.
5552** ^The sqlite3_result_text64() interface sets the return value of an
5553** application-defined function to be a text string in an encoding
5554** specified by the fifth (and last) parameter, which must be one
5555** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
5556** ^SQLite takes the text result from the application from
5557** the 2nd parameter of the sqlite3_result_text* interfaces.
5558** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5559** is negative, then SQLite takes result text from the 2nd parameter
5560** through the first zero character.
5561** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5562** is non-negative, then as many bytes (not characters) of the text
5563** pointed to by the 2nd parameter are taken as the application-defined
5564** function result. If the 3rd parameter is non-negative, then it
5565** must be the byte offset into the string where the NUL terminator would
5566** appear if the string where NUL terminated. If any NUL characters occur
5567** in the string at a byte offset that is less than the value of the 3rd
5568** parameter, then the resulting string will contain embedded NULs and the
5569** result of expressions operating on strings with embedded NULs is undefined.
5570** ^If the 4th parameter to the sqlite3_result_text* interfaces
5571** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
5572** function as the destructor on the text or BLOB result when it has
5573** finished using that result.
5574** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
5575** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
5576** assumes that the text or BLOB result is in constant space and does not
5577** copy the content of the parameter nor call a destructor on the content
5578** when it has finished using that result.
5579** ^If the 4th parameter to the sqlite3_result_text* interfaces
5580** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
5581** then SQLite makes a copy of the result into space obtained
5582** from [sqlite3_malloc()] before it returns.
5583**
5584** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and
5585** sqlite3_result_text16be() routines, and for sqlite3_result_text64()
5586** when the encoding is not UTF8, if the input UTF16 begins with a
5587** byte-order mark (BOM, U+FEFF) then the BOM is removed from the
5588** string and the rest of the string is interpreted according to the
5589** byte-order specified by the BOM. ^The byte-order specified by
5590** the BOM at the beginning of the text overrides the byte-order
5591** specified by the interface procedure. ^So, for example, if
5592** sqlite3_result_text16le() is invoked with text that begins
5593** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the
5594** first two bytes of input are skipped and the remaining input
5595** is interpreted as UTF16BE text.
5596**
5597** ^For UTF16 input text to the sqlite3_result_text16(),
5598** sqlite3_result_text16be(), sqlite3_result_text16le(), and
5599** sqlite3_result_text64() routines, if the text contains invalid
5600** UTF16 characters, the invalid characters might be converted
5601** into the unicode replacement character, U+FFFD.
5602**
5603** ^The sqlite3_result_value() interface sets the result of
5604** the application-defined function to be a copy of the
5605** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
5606** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
5607** so that the [sqlite3_value] specified in the parameter may change or
5608** be deallocated after sqlite3_result_value() returns without harm.
5609** ^A [protected sqlite3_value] object may always be used where an
5610** [unprotected sqlite3_value] object is required, so either
5611** kind of [sqlite3_value] object can be used with this interface.
5612**
5613** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
5614** SQL NULL value, just like [sqlite3_result_null(C)], except that it
5615** also associates the host-language pointer P or type T with that
5616** NULL value such that the pointer can be retrieved within an
5617** [application-defined SQL function] using [sqlite3_value_pointer()].
5618** ^If the D parameter is not NULL, then it is a pointer to a destructor
5619** for the P parameter. ^SQLite invokes D with P as its only argument
5620** when SQLite is finished with P. The T parameter should be a static
5621** string and preferably a string literal. The sqlite3_result_pointer()
5622** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5623**
5624** If these routines are called from within the different thread
5625** than the one containing the application-defined function that received
5626** the [sqlite3_context] pointer, the results are undefined.
5627*/
5628
5629
5630/*
5631** CAPI3REF: Setting The Subtype Of An SQL Function
5632** METHOD: sqlite3_context
5633**
5634** The sqlite3_result_subtype(C,T) function causes the subtype of
5635** the result from the [application-defined SQL function] with
5636** [sqlite3_context] C to be the value T. Only the lower 8 bits
5637** of the subtype T are preserved in current versions of SQLite;
5638** higher order bits are discarded.
5639** The number of subtype bytes preserved by SQLite might increase
5640** in future releases of SQLite.
5641*/
5642
5643/*
5644** CAPI3REF: Define New Collating Sequences
5645** METHOD: sqlite3
5646**
5647** ^These functions add, remove, or modify a [collation] associated
5648** with the [database connection] specified as the first argument.
5649**
5650** ^The name of the collation is a UTF-8 string
5651** for sqlite3_create_collation() and sqlite3_create_collation_v2()
5652** and a UTF-16 string in native byte order for sqlite3_create_collation16().
5653** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
5654** considered to be the same name.
5655**
5656** ^(The third argument (eTextRep) must be one of the constants:
5657** <ul>
5658** <li> [SQLITE_UTF8],
5659** <li> [SQLITE_UTF16LE],
5660** <li> [SQLITE_UTF16BE],
5661** <li> [SQLITE_UTF16], or
5662** <li> [SQLITE_UTF16_ALIGNED].
5663** </ul>)^
5664** ^The eTextRep argument determines the encoding of strings passed
5665** to the collating function callback, xCompare.
5666** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
5667** force strings to be UTF16 with native byte order.
5668** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
5669** on an even byte address.
5670**
5671** ^The fourth argument, pArg, is an application data pointer that is passed
5672** through as the first argument to the collating function callback.
5673**
5674** ^The fifth argument, xCompare, is a pointer to the collating function.
5675** ^Multiple collating functions can be registered using the same name but
5676** with different eTextRep parameters and SQLite will use whichever
5677** function requires the least amount of data transformation.
5678** ^If the xCompare argument is NULL then the collating function is
5679** deleted. ^When all collating functions having the same name are deleted,
5680** that collation is no longer usable.
5681**
5682** ^The collating function callback is invoked with a copy of the pArg
5683** application data pointer and with two strings in the encoding specified
5684** by the eTextRep argument. The two integer parameters to the collating
5685** function callback are the length of the two strings, in bytes. The collating
5686** function must return an integer that is negative, zero, or positive
5687** if the first string is less than, equal to, or greater than the second,
5688** respectively. A collating function must always return the same answer
5689** given the same inputs. If two or more collating functions are registered
5690** to the same collation name (using different eTextRep values) then all
5691** must give an equivalent answer when invoked with equivalent strings.
5692** The collating function must obey the following properties for all
5693** strings A, B, and C:
5694**
5695** <ol>
5696** <li> If A==B then B==A.
5697** <li> If A==B and B==C then A==C.
5698** <li> If A&lt;B THEN B&gt;A.
5699** <li> If A&lt;B and B&lt;C then A&lt;C.
5700** </ol>
5701**
5702** If a collating function fails any of the above constraints and that
5703** collating function is registered and used, then the behavior of SQLite
5704** is undefined.
5705**
5706** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
5707** with the addition that the xDestroy callback is invoked on pArg when
5708** the collating function is deleted.
5709** ^Collating functions are deleted when they are overridden by later
5710** calls to the collation creation functions or when the
5711** [database connection] is closed using [sqlite3_close()].
5712**
5713** ^The xDestroy callback is <u>not</u> called if the
5714** sqlite3_create_collation_v2() function fails. Applications that invoke
5715** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
5716** check the return code and dispose of the application data pointer
5717** themselves rather than expecting SQLite to deal with it for them.
5718** This is different from every other SQLite interface. The inconsistency
5719** is unfortunate but cannot be changed without breaking backwards
5720** compatibility.
5721**
5722** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
5723*/
5724
5725/*
5726** CAPI3REF: Collation Needed Callbacks
5727** METHOD: sqlite3
5728**
5729** ^To avoid having to register all collation sequences before a database
5730** can be used, a single callback function may be registered with the
5731** [database connection] to be invoked whenever an undefined collation
5732** sequence is required.
5733**
5734** ^If the function is registered using the sqlite3_collation_needed() API,
5735** then it is passed the names of undefined collation sequences as strings
5736** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
5737** the names are passed as UTF-16 in machine native byte order.
5738** ^A call to either function replaces the existing collation-needed callback.
5739**
5740** ^(When the callback is invoked, the first argument passed is a copy
5741** of the second argument to sqlite3_collation_needed() or
5742** sqlite3_collation_needed16(). The second argument is the database
5743** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
5744** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
5745** sequence function required. The fourth parameter is the name of the
5746** required collation sequence.)^
5747**
5748** The callback function should register the desired collation using
5749** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
5750** [sqlite3_create_collation_v2()].
5751*/
5752
5753#ifdef SQLITE_ENABLE_CEROD
5754/*
5755** Specify the activation key for a CEROD database. Unless
5756** activated, none of the CEROD routines will work.
5757*/
5758#endif
5759
5760/*
5761** CAPI3REF: Suspend Execution For A Short Time
5762**
5763** The sqlite3_sleep() function causes the current thread to suspend execution
5764** for at least a number of milliseconds specified in its parameter.
5765**
5766** If the operating system does not support sleep requests with
5767** millisecond time resolution, then the time will be rounded up to
5768** the nearest second. The number of milliseconds of sleep actually
5769** requested from the operating system is returned.
5770**
5771** ^SQLite implements this interface by calling the xSleep()
5772** method of the default [sqlite3_vfs] object. If the xSleep() method
5773** of the default VFS is not implemented correctly, or not implemented at
5774** all, then the behavior of sqlite3_sleep() may deviate from the description
5775** in the previous paragraphs.
5776*/
5777
5778/*
5779** CAPI3REF: Name Of The Folder Holding Temporary Files
5780**
5781** ^(If this global variable is made to point to a string which is
5782** the name of a folder (a.k.a. directory), then all temporary files
5783** created by SQLite when using a built-in [sqlite3_vfs | VFS]
5784** will be placed in that directory.)^ ^If this variable
5785** is a NULL pointer, then SQLite performs a search for an appropriate
5786** temporary file directory.
5787**
5788** Applications are strongly discouraged from using this global variable.
5789** It is required to set a temporary folder on Windows Runtime (WinRT).
5790** But for all other platforms, it is highly recommended that applications
5791** neither read nor write this variable. This global variable is a relic
5792** that exists for backwards compatibility of legacy applications and should
5793** be avoided in new projects.
5794**
5795** It is not safe to read or modify this variable in more than one
5796** thread at a time. It is not safe to read or modify this variable
5797** if a [database connection] is being used at the same time in a separate
5798** thread.
5799** It is intended that this variable be set once
5800** as part of process initialization and before any SQLite interface
5801** routines have been called and that this variable remain unchanged
5802** thereafter.
5803**
5804** ^The [temp_store_directory pragma] may modify this variable and cause
5805** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
5806** the [temp_store_directory pragma] always assumes that any string
5807** that this variable points to is held in memory obtained from
5808** [sqlite3_malloc] and the pragma may attempt to free that memory
5809** using [sqlite3_free].
5810** Hence, if this variable is modified directly, either it should be
5811** made NULL or made to point to memory obtained from [sqlite3_malloc]
5812** or else the use of the [temp_store_directory pragma] should be avoided.
5813** Except when requested by the [temp_store_directory pragma], SQLite
5814** does not free the memory that sqlite3_temp_directory points to. If
5815** the application wants that memory to be freed, it must do
5816** so itself, taking care to only do so after all [database connection]
5817** objects have been destroyed.
5818**
5819** <b>Note to Windows Runtime users:</b> The temporary directory must be set
5820** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
5821** features that require the use of temporary files may fail. Here is an
5822** example of how to do this using C++ with the Windows Runtime:
5823**
5824** <blockquote><pre>
5825** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
5826** &nbsp; TemporaryFolder->Path->Data();
5827** char zPathBuf&#91;MAX_PATH + 1&#93;;
5828** memset(zPathBuf, 0, sizeof(zPathBuf));
5829** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
5830** &nbsp; NULL, NULL);
5831** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
5832** </pre></blockquote>
5833*/
5834SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
5835
5836/*
5837** CAPI3REF: Name Of The Folder Holding Database Files
5838**
5839** ^(If this global variable is made to point to a string which is
5840** the name of a folder (a.k.a. directory), then all database files
5841** specified with a relative pathname and created or accessed by
5842** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
5843** to be relative to that directory.)^ ^If this variable is a NULL
5844** pointer, then SQLite assumes that all database files specified
5845** with a relative pathname are relative to the current directory
5846** for the process. Only the windows VFS makes use of this global
5847** variable; it is ignored by the unix VFS.
5848**
5849** Changing the value of this variable while a database connection is
5850** open can result in a corrupt database.
5851**
5852** It is not safe to read or modify this variable in more than one
5853** thread at a time. It is not safe to read or modify this variable
5854** if a [database connection] is being used at the same time in a separate
5855** thread.
5856** It is intended that this variable be set once
5857** as part of process initialization and before any SQLite interface
5858** routines have been called and that this variable remain unchanged
5859** thereafter.
5860**
5861** ^The [data_store_directory pragma] may modify this variable and cause
5862** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
5863** the [data_store_directory pragma] always assumes that any string
5864** that this variable points to is held in memory obtained from
5865** [sqlite3_malloc] and the pragma may attempt to free that memory
5866** using [sqlite3_free].
5867** Hence, if this variable is modified directly, either it should be
5868** made NULL or made to point to memory obtained from [sqlite3_malloc]
5869** or else the use of the [data_store_directory pragma] should be avoided.
5870*/
5871SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
5872
5873/*
5874** CAPI3REF: Win32 Specific Interface
5875**
5876** These interfaces are available only on Windows. The
5877** [sqlite3_win32_set_directory] interface is used to set the value associated
5878** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
5879** zValue, depending on the value of the type parameter. The zValue parameter
5880** should be NULL to cause the previous value to be freed via [sqlite3_free];
5881** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
5882** prior to being used. The [sqlite3_win32_set_directory] interface returns
5883** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
5884** or [SQLITE_NOMEM] if memory could not be allocated. The value of the
5885** [sqlite3_data_directory] variable is intended to act as a replacement for
5886** the current directory on the sub-platforms of Win32 where that concept is
5887** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and
5888** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
5889** sqlite3_win32_set_directory interface except the string parameter must be
5890** UTF-8 or UTF-16, respectively.
5891*/
5892
5893/*
5894** CAPI3REF: Win32 Directory Types
5895**
5896** These macros are only available on Windows. They define the allowed values
5897** for the type argument to the [sqlite3_win32_set_directory] interface.
5898*/
5899#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1
5900#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2
5901
5902/*
5903** CAPI3REF: Test For Auto-Commit Mode
5904** KEYWORDS: {autocommit mode}
5905** METHOD: sqlite3
5906**
5907** ^The sqlite3_get_autocommit() interface returns non-zero or
5908** zero if the given database connection is or is not in autocommit mode,
5909** respectively. ^Autocommit mode is on by default.
5910** ^Autocommit mode is disabled by a [BEGIN] statement.
5911** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
5912**
5913** If certain kinds of errors occur on a statement within a multi-statement
5914** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
5915** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
5916** transaction might be rolled back automatically. The only way to
5917** find out whether SQLite automatically rolled back the transaction after
5918** an error is to use this function.
5919**
5920** If another thread changes the autocommit status of the database
5921** connection while this routine is running, then the return value
5922** is undefined.
5923*/
5924
5925/*
5926** CAPI3REF: Find The Database Handle Of A Prepared Statement
5927** METHOD: sqlite3_stmt
5928**
5929** ^The sqlite3_db_handle interface returns the [database connection] handle
5930** to which a [prepared statement] belongs. ^The [database connection]
5931** returned by sqlite3_db_handle is the same [database connection]
5932** that was the first argument
5933** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
5934** create the statement in the first place.
5935*/
5936
5937/*
5938** CAPI3REF: Return The Schema Name For A Database Connection
5939** METHOD: sqlite3
5940**
5941** ^The sqlite3_db_name(D,N) interface returns a pointer to the schema name
5942** for the N-th database on database connection D, or a NULL pointer of N is
5943** out of range. An N value of 0 means the main database file. An N of 1 is
5944** the "temp" schema. Larger values of N correspond to various ATTACH-ed
5945** databases.
5946**
5947** Space to hold the string that is returned by sqlite3_db_name() is managed
5948** by SQLite itself. The string might be deallocated by any operation that
5949** changes the schema, including [ATTACH] or [DETACH] or calls to
5950** [sqlite3_serialize()] or [sqlite3_deserialize()], even operations that
5951** occur on a different thread. Applications that need to
5952** remember the string long-term should make their own copy. Applications that
5953** are accessing the same database connection simultaneously on multiple
5954** threads should mutex-protect calls to this API and should make their own
5955** private copy of the result prior to releasing the mutex.
5956*/
5957
5958/*
5959** CAPI3REF: Return The Filename For A Database Connection
5960** METHOD: sqlite3
5961**
5962** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename
5963** associated with database N of connection D.
5964** ^If there is no attached database N on the database
5965** connection D, or if database N is a temporary or in-memory database, then
5966** this function will return either a NULL pointer or an empty string.
5967**
5968** ^The string value returned by this routine is owned and managed by
5969** the database connection. ^The value will be valid until the database N
5970** is [DETACH]-ed or until the database connection closes.
5971**
5972** ^The filename returned by this function is the output of the
5973** xFullPathname method of the [VFS]. ^In other words, the filename
5974** will be an absolute pathname, even if the filename used
5975** to open the database originally was a URI or relative pathname.
5976**
5977** If the filename pointer returned by this routine is not NULL, then it
5978** can be used as the filename input parameter to these routines:
5979** <ul>
5980** <li> [sqlite3_uri_parameter()]
5981** <li> [sqlite3_uri_boolean()]
5982** <li> [sqlite3_uri_int64()]
5983** <li> [sqlite3_filename_database()]
5984** <li> [sqlite3_filename_journal()]
5985** <li> [sqlite3_filename_wal()]
5986** </ul>
5987*/
5988
5989/*
5990** CAPI3REF: Determine if a database is read-only
5991** METHOD: sqlite3
5992**
5993** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
5994** of connection D is read-only, 0 if it is read/write, or -1 if N is not
5995** the name of a database on connection D.
5996*/
5997
5998/*
5999** CAPI3REF: Determine the transaction state of a database
6000** METHOD: sqlite3
6001**
6002** ^The sqlite3_txn_state(D,S) interface returns the current
6003** [transaction state] of schema S in database connection D. ^If S is NULL,
6004** then the highest transaction state of any schema on database connection D
6005** is returned. Transaction states are (in order of lowest to highest):
6006** <ol>
6007** <li value="0"> SQLITE_TXN_NONE
6008** <li value="1"> SQLITE_TXN_READ
6009** <li value="2"> SQLITE_TXN_WRITE
6010** </ol>
6011** ^If the S argument to sqlite3_txn_state(D,S) is not the name of
6012** a valid schema, then -1 is returned.
6013*/
6014
6015/*
6016** CAPI3REF: Allowed return values from [sqlite3_txn_state()]
6017** KEYWORDS: {transaction state}
6018**
6019** These constants define the current transaction state of a database file.
6020** ^The [sqlite3_txn_state(D,S)] interface returns one of these
6021** constants in order to describe the transaction state of schema S
6022** in [database connection] D.
6023**
6024** <dl>
6025** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt>
6026** <dd>The SQLITE_TXN_NONE state means that no transaction is currently
6027** pending.</dd>
6028**
6029** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt>
6030** <dd>The SQLITE_TXN_READ state means that the database is currently
6031** in a read transaction. Content has been read from the database file
6032** but nothing in the database file has changed. The transaction state
6033** will advanced to SQLITE_TXN_WRITE if any changes occur and there are
6034** no other conflicting concurrent write transactions. The transaction
6035** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or
6036** [COMMIT].</dd>
6037**
6038** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt>
6039** <dd>The SQLITE_TXN_WRITE state means that the database is currently
6040** in a write transaction. Content has been written to the database file
6041** but has not yet committed. The transaction state will change to
6042** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd>
6043*/
6044#define SQLITE_TXN_NONE 0
6045#define SQLITE_TXN_READ 1
6046#define SQLITE_TXN_WRITE 2
6047
6048/*
6049** CAPI3REF: Find the next prepared statement
6050** METHOD: sqlite3
6051**
6052** ^This interface returns a pointer to the next [prepared statement] after
6053** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
6054** then this interface returns a pointer to the first prepared statement
6055** associated with the database connection pDb. ^If no prepared statement
6056** satisfies the conditions of this routine, it returns NULL.
6057**
6058** The [database connection] pointer D in a call to
6059** [sqlite3_next_stmt(D,S)] must refer to an open database
6060** connection and in particular must not be a NULL pointer.
6061*/
6062
6063/*
6064** CAPI3REF: Commit And Rollback Notification Callbacks
6065** METHOD: sqlite3
6066**
6067** ^The sqlite3_commit_hook() interface registers a callback
6068** function to be invoked whenever a transaction is [COMMIT | committed].
6069** ^Any callback set by a previous call to sqlite3_commit_hook()
6070** for the same database connection is overridden.
6071** ^The sqlite3_rollback_hook() interface registers a callback
6072** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
6073** ^Any callback set by a previous call to sqlite3_rollback_hook()
6074** for the same database connection is overridden.
6075** ^The pArg argument is passed through to the callback.
6076** ^If the callback on a commit hook function returns non-zero,
6077** then the commit is converted into a rollback.
6078**
6079** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
6080** return the P argument from the previous call of the same function
6081** on the same [database connection] D, or NULL for
6082** the first call for each function on D.
6083**
6084** The commit and rollback hook callbacks are not reentrant.
6085** The callback implementation must not do anything that will modify
6086** the database connection that invoked the callback. Any actions
6087** to modify the database connection must be deferred until after the
6088** completion of the [sqlite3_step()] call that triggered the commit
6089** or rollback hook in the first place.
6090** Note that running any other SQL statements, including SELECT statements,
6091** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
6092** the database connections for the meaning of "modify" in this paragraph.
6093**
6094** ^Registering a NULL function disables the callback.
6095**
6096** ^When the commit hook callback routine returns zero, the [COMMIT]
6097** operation is allowed to continue normally. ^If the commit hook
6098** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
6099** ^The rollback hook is invoked on a rollback that results from a commit
6100** hook returning non-zero, just as it would be with any other rollback.
6101**
6102** ^For the purposes of this API, a transaction is said to have been
6103** rolled back if an explicit "ROLLBACK" statement is executed, or
6104** an error or constraint causes an implicit rollback to occur.
6105** ^The rollback callback is not invoked if a transaction is
6106** automatically rolled back because the database connection is closed.
6107**
6108** See also the [sqlite3_update_hook()] interface.
6109*/
6110
6111/*
6112** CAPI3REF: Autovacuum Compaction Amount Callback
6113** METHOD: sqlite3
6114**
6115** ^The sqlite3_autovacuum_pages(D,C,P,X) interface registers a callback
6116** function C that is invoked prior to each autovacuum of the database
6117** file. ^The callback is passed a copy of the generic data pointer (P),
6118** the schema-name of the attached database that is being autovacuumed,
6119** the the size of the database file in pages, the number of free pages,
6120** and the number of bytes per page, respectively. The callback should
6121** return the number of free pages that should be removed by the
6122** autovacuum. ^If the callback returns zero, then no autovacuum happens.
6123** ^If the value returned is greater than or equal to the number of
6124** free pages, then a complete autovacuum happens.
6125**
6126** <p>^If there are multiple ATTACH-ed database files that are being
6127** modified as part of a transaction commit, then the autovacuum pages
6128** callback is invoked separately for each file.
6129**
6130** <p><b>The callback is not reentrant.</b> The callback function should
6131** not attempt to invoke any other SQLite interface. If it does, bad
6132** things may happen, including segmentation faults and corrupt database
6133** files. The callback function should be a simple function that
6134** does some arithmetic on its input parameters and returns a result.
6135**
6136** ^The X parameter to sqlite3_autovacuum_pages(D,C,P,X) is an optional
6137** destructor for the P parameter. ^If X is not NULL, then X(P) is
6138** invoked whenever the database connection closes or when the callback
6139** is overwritten by another invocation of sqlite3_autovacuum_pages().
6140**
6141** <p>^There is only one autovacuum pages callback per database connection.
6142** ^Each call to the sqlite3_autovacuum_pages() interface overrides all
6143** previous invocations for that database connection. ^If the callback
6144** argument (C) to sqlite3_autovacuum_pages(D,C,P,X) is a NULL pointer,
6145** then the autovacuum steps callback is cancelled. The return value
6146** from sqlite3_autovacuum_pages() is normally SQLITE_OK, but might
6147** be some other error code if something goes wrong. The current
6148** implementation will only return SQLITE_OK or SQLITE_MISUSE, but other
6149** return codes might be added in future releases.
6150**
6151** <p>If no autovacuum pages callback is specified (the usual case) or
6152** a NULL pointer is provided for the callback,
6153** then the default behavior is to vacuum all free pages. So, in other
6154** words, the default behavior is the same as if the callback function
6155** were something like this:
6156**
6157** <blockquote><pre>
6158** &nbsp; unsigned int demonstration_autovac_pages_callback(
6159** &nbsp; void *pClientData,
6160** &nbsp; const char *zSchema,
6161** &nbsp; unsigned int nDbPage,
6162** &nbsp; unsigned int nFreePage,
6163** &nbsp; unsigned int nBytePerPage
6164** &nbsp; ){
6165** &nbsp; return nFreePage;
6166** &nbsp; }
6167** </pre></blockquote>
6168*/
6169
6170
6171/*
6172** CAPI3REF: Data Change Notification Callbacks
6173** METHOD: sqlite3
6174**
6175** ^The sqlite3_update_hook() interface registers a callback function
6176** with the [database connection] identified by the first argument
6177** to be invoked whenever a row is updated, inserted or deleted in
6178** a [rowid table].
6179** ^Any callback set by a previous call to this function
6180** for the same database connection is overridden.
6181**
6182** ^The second argument is a pointer to the function to invoke when a
6183** row is updated, inserted or deleted in a rowid table.
6184** ^The first argument to the callback is a copy of the third argument
6185** to sqlite3_update_hook().
6186** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
6187** or [SQLITE_UPDATE], depending on the operation that caused the callback
6188** to be invoked.
6189** ^The third and fourth arguments to the callback contain pointers to the
6190** database and table name containing the affected row.
6191** ^The final callback parameter is the [rowid] of the row.
6192** ^In the case of an update, this is the [rowid] after the update takes place.
6193**
6194** ^(The update hook is not invoked when internal system tables are
6195** modified (i.e. sqlite_sequence).)^
6196** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
6197**
6198** ^In the current implementation, the update hook
6199** is not invoked when conflicting rows are deleted because of an
6200** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
6201** invoked when rows are deleted using the [truncate optimization].
6202** The exceptions defined in this paragraph might change in a future
6203** release of SQLite.
6204**
6205** The update hook implementation must not do anything that will modify
6206** the database connection that invoked the update hook. Any actions
6207** to modify the database connection must be deferred until after the
6208** completion of the [sqlite3_step()] call that triggered the update hook.
6209** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
6210** database connections for the meaning of "modify" in this paragraph.
6211**
6212** ^The sqlite3_update_hook(D,C,P) function
6213** returns the P argument from the previous call
6214** on the same [database connection] D, or NULL for
6215** the first call on D.
6216**
6217** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
6218** and [sqlite3_preupdate_hook()] interfaces.
6219*/
6220
6221/*
6222** CAPI3REF: Enable Or Disable Shared Pager Cache
6223**
6224** ^(This routine enables or disables the sharing of the database cache
6225** and schema data structures between [database connection | connections]
6226** to the same database. Sharing is enabled if the argument is true
6227** and disabled if the argument is false.)^
6228**
6229** ^Cache sharing is enabled and disabled for an entire process.
6230** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
6231** In prior versions of SQLite,
6232** sharing was enabled or disabled for each thread separately.
6233**
6234** ^(The cache sharing mode set by this interface effects all subsequent
6235** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
6236** Existing database connections continue to use the sharing mode
6237** that was in effect at the time they were opened.)^
6238**
6239** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
6240** successfully. An [error code] is returned otherwise.)^
6241**
6242** ^Shared cache is disabled by default. It is recommended that it stay
6243** that way. In other words, do not use this routine. This interface
6244** continues to be provided for historical compatibility, but its use is
6245** discouraged. Any use of shared cache is discouraged. If shared cache
6246** must be used, it is recommended that shared cache only be enabled for
6247** individual database connections using the [sqlite3_open_v2()] interface
6248** with the [SQLITE_OPEN_SHAREDCACHE] flag.
6249**
6250** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
6251** and will always return SQLITE_MISUSE. On those systems,
6252** shared cache mode should be enabled per-database connection via
6253** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
6254**
6255** This interface is threadsafe on processors where writing a
6256** 32-bit integer is atomic.
6257**
6258** See Also: [SQLite Shared-Cache Mode]
6259*/
6260
6261/*
6262** CAPI3REF: Attempt To Free Heap Memory
6263**
6264** ^The sqlite3_release_memory() interface attempts to free N bytes
6265** of heap memory by deallocating non-essential memory allocations
6266** held by the database library. Memory used to cache database
6267** pages to improve performance is an example of non-essential memory.
6268** ^sqlite3_release_memory() returns the number of bytes actually freed,
6269** which might be more or less than the amount requested.
6270** ^The sqlite3_release_memory() routine is a no-op returning zero
6271** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
6272**
6273** See also: [sqlite3_db_release_memory()]
6274*/
6275
6276/*
6277** CAPI3REF: Free Memory Used By A Database Connection
6278** METHOD: sqlite3
6279**
6280** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
6281** memory as possible from database connection D. Unlike the
6282** [sqlite3_release_memory()] interface, this interface is in effect even
6283** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
6284** omitted.
6285**
6286** See also: [sqlite3_release_memory()]
6287*/
6288
6289/*
6290** CAPI3REF: Impose A Limit On Heap Size
6291**
6292** These interfaces impose limits on the amount of heap memory that will be
6293** by all database connections within a single process.
6294**
6295** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
6296** soft limit on the amount of heap memory that may be allocated by SQLite.
6297** ^SQLite strives to keep heap memory utilization below the soft heap
6298** limit by reducing the number of pages held in the page cache
6299** as heap memory usages approaches the limit.
6300** ^The soft heap limit is "soft" because even though SQLite strives to stay
6301** below the limit, it will exceed the limit rather than generate
6302** an [SQLITE_NOMEM] error. In other words, the soft heap limit
6303** is advisory only.
6304**
6305** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of
6306** N bytes on the amount of memory that will be allocated. ^The
6307** sqlite3_hard_heap_limit64(N) interface is similar to
6308** sqlite3_soft_heap_limit64(N) except that memory allocations will fail
6309** when the hard heap limit is reached.
6310**
6311** ^The return value from both sqlite3_soft_heap_limit64() and
6312** sqlite3_hard_heap_limit64() is the size of
6313** the heap limit prior to the call, or negative in the case of an
6314** error. ^If the argument N is negative
6315** then no change is made to the heap limit. Hence, the current
6316** size of heap limits can be determined by invoking
6317** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1).
6318**
6319** ^Setting the heap limits to zero disables the heap limiter mechanism.
6320**
6321** ^The soft heap limit may not be greater than the hard heap limit.
6322** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N)
6323** is invoked with a value of N that is greater than the hard heap limit,
6324** the the soft heap limit is set to the value of the hard heap limit.
6325** ^The soft heap limit is automatically enabled whenever the hard heap
6326** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and
6327** the soft heap limit is outside the range of 1..N, then the soft heap
6328** limit is set to N. ^Invoking sqlite3_soft_heap_limit64(0) when the
6329** hard heap limit is enabled makes the soft heap limit equal to the
6330** hard heap limit.
6331**
6332** The memory allocation limits can also be adjusted using
6333** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit].
6334**
6335** ^(The heap limits are not enforced in the current implementation
6336** if one or more of following conditions are true:
6337**
6338** <ul>
6339** <li> The limit value is set to zero.
6340** <li> Memory accounting is disabled using a combination of the
6341** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
6342** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
6343** <li> An alternative page cache implementation is specified using
6344** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
6345** <li> The page cache allocates from its own memory pool supplied
6346** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
6347** from the heap.
6348** </ul>)^
6349**
6350** The circumstances under which SQLite will enforce the heap limits may
6351** changes in future releases of SQLite.
6352*/
6353
6354/*
6355** CAPI3REF: Deprecated Soft Heap Limit Interface
6356** DEPRECATED
6357**
6358** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
6359** interface. This routine is provided for historical compatibility
6360** only. All new applications should use the
6361** [sqlite3_soft_heap_limit64()] interface rather than this one.
6362*/
6363
6364
6365/*
6366** CAPI3REF: Extract Metadata About A Column Of A Table
6367** METHOD: sqlite3
6368**
6369** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
6370** information about column C of table T in database D
6371** on [database connection] X.)^ ^The sqlite3_table_column_metadata()
6372** interface returns SQLITE_OK and fills in the non-NULL pointers in
6373** the final five arguments with appropriate values if the specified
6374** column exists. ^The sqlite3_table_column_metadata() interface returns
6375** SQLITE_ERROR if the specified column does not exist.
6376** ^If the column-name parameter to sqlite3_table_column_metadata() is a
6377** NULL pointer, then this routine simply checks for the existence of the
6378** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
6379** does not. If the table name parameter T in a call to
6380** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
6381** undefined behavior.
6382**
6383** ^The column is identified by the second, third and fourth parameters to
6384** this function. ^(The second parameter is either the name of the database
6385** (i.e. "main", "temp", or an attached database) containing the specified
6386** table or NULL.)^ ^If it is NULL, then all attached databases are searched
6387** for the table using the same algorithm used by the database engine to
6388** resolve unqualified table references.
6389**
6390** ^The third and fourth parameters to this function are the table and column
6391** name of the desired column, respectively.
6392**
6393** ^Metadata is returned by writing to the memory locations passed as the 5th
6394** and subsequent parameters to this function. ^Any of these arguments may be
6395** NULL, in which case the corresponding element of metadata is omitted.
6396**
6397** ^(<blockquote>
6398** <table border="1">
6399** <tr><th> Parameter <th> Output<br>Type <th> Description
6400**
6401** <tr><td> 5th <td> const char* <td> Data type
6402** <tr><td> 6th <td> const char* <td> Name of default collation sequence
6403** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
6404** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
6405** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
6406** </table>
6407** </blockquote>)^
6408**
6409** ^The memory pointed to by the character pointers returned for the
6410** declaration type and collation sequence is valid until the next
6411** call to any SQLite API function.
6412**
6413** ^If the specified table is actually a view, an [error code] is returned.
6414**
6415** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
6416** is not a [WITHOUT ROWID] table and an
6417** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
6418** parameters are set for the explicitly declared column. ^(If there is no
6419** [INTEGER PRIMARY KEY] column, then the outputs
6420** for the [rowid] are set as follows:
6421**
6422** <pre>
6423** data type: "INTEGER"
6424** collation sequence: "BINARY"
6425** not null: 0
6426** primary key: 1
6427** auto increment: 0
6428** </pre>)^
6429**
6430** ^This function causes all database schemas to be read from disk and
6431** parsed, if that has not already been done, and returns an error if
6432** any errors are encountered while loading the schema.
6433*/
6434
6435/*
6436** CAPI3REF: Load An Extension
6437** METHOD: sqlite3
6438**
6439** ^This interface loads an SQLite extension library from the named file.
6440**
6441** ^The sqlite3_load_extension() interface attempts to load an
6442** [SQLite extension] library contained in the file zFile. If
6443** the file cannot be loaded directly, attempts are made to load
6444** with various operating-system specific extensions added.
6445** So for example, if "samplelib" cannot be loaded, then names like
6446** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
6447** be tried also.
6448**
6449** ^The entry point is zProc.
6450** ^(zProc may be 0, in which case SQLite will try to come up with an
6451** entry point name on its own. It first tries "sqlite3_extension_init".
6452** If that does not work, it constructs a name "sqlite3_X_init" where the
6453** X is consists of the lower-case equivalent of all ASCII alphabetic
6454** characters in the filename from the last "/" to the first following
6455** "." and omitting any initial "lib".)^
6456** ^The sqlite3_load_extension() interface returns
6457** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
6458** ^If an error occurs and pzErrMsg is not 0, then the
6459** [sqlite3_load_extension()] interface shall attempt to
6460** fill *pzErrMsg with error message text stored in memory
6461** obtained from [sqlite3_malloc()]. The calling function
6462** should free this memory by calling [sqlite3_free()].
6463**
6464** ^Extension loading must be enabled using
6465** [sqlite3_enable_load_extension()] or
6466** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
6467** prior to calling this API,
6468** otherwise an error will be returned.
6469**
6470** <b>Security warning:</b> It is recommended that the
6471** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
6472** interface. The use of the [sqlite3_enable_load_extension()] interface
6473** should be avoided. This will keep the SQL function [load_extension()]
6474** disabled and prevent SQL injections from giving attackers
6475** access to extension loading capabilities.
6476**
6477** See also the [load_extension() SQL function].
6478*/
6479
6480/*
6481** CAPI3REF: Enable Or Disable Extension Loading
6482** METHOD: sqlite3
6483**
6484** ^So as not to open security holes in older applications that are
6485** unprepared to deal with [extension loading], and as a means of disabling
6486** [extension loading] while evaluating user-entered SQL, the following API
6487** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
6488**
6489** ^Extension loading is off by default.
6490** ^Call the sqlite3_enable_load_extension() routine with onoff==1
6491** to turn extension loading on and call it with onoff==0 to turn
6492** it back off again.
6493**
6494** ^This interface enables or disables both the C-API
6495** [sqlite3_load_extension()] and the SQL function [load_extension()].
6496** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
6497** to enable or disable only the C-API.)^
6498**
6499** <b>Security warning:</b> It is recommended that extension loading
6500** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
6501** rather than this interface, so the [load_extension()] SQL function
6502** remains disabled. This will prevent SQL injections from giving attackers
6503** access to extension loading capabilities.
6504*/
6505
6506/*
6507** CAPI3REF: Automatically Load Statically Linked Extensions
6508**
6509** ^This interface causes the xEntryPoint() function to be invoked for
6510** each new [database connection] that is created. The idea here is that
6511** xEntryPoint() is the entry point for a statically linked [SQLite extension]
6512** that is to be automatically loaded into all new database connections.
6513**
6514** ^(Even though the function prototype shows that xEntryPoint() takes
6515** no arguments and returns void, SQLite invokes xEntryPoint() with three
6516** arguments and expects an integer result as if the signature of the
6517** entry point where as follows:
6518**
6519** <blockquote><pre>
6520** &nbsp; int xEntryPoint(
6521** &nbsp; sqlite3 *db,
6522** &nbsp; const char **pzErrMsg,
6523** &nbsp; const struct sqlite3_api_routines *pThunk
6524** &nbsp; );
6525** </pre></blockquote>)^
6526**
6527** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
6528** point to an appropriate error message (obtained from [sqlite3_mprintf()])
6529** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
6530** is NULL before calling the xEntryPoint(). ^SQLite will invoke
6531** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
6532** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
6533** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
6534**
6535** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
6536** on the list of automatic extensions is a harmless no-op. ^No entry point
6537** will be called more than once for each database connection that is opened.
6538**
6539** See also: [sqlite3_reset_auto_extension()]
6540** and [sqlite3_cancel_auto_extension()]
6541*/
6542
6543/*
6544** CAPI3REF: Cancel Automatic Extension Loading
6545**
6546** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
6547** initialization routine X that was registered using a prior call to
6548** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)]
6549** routine returns 1 if initialization routine X was successfully
6550** unregistered and it returns 0 if X was not on the list of initialization
6551** routines.
6552*/
6553
6554/*
6555** CAPI3REF: Reset Automatic Extension Loading
6556**
6557** ^This interface disables all automatic extensions previously
6558** registered using [sqlite3_auto_extension()].
6559*/
6560
6561/*
6562** The interface to the virtual-table mechanism is currently considered
6563** to be experimental. The interface might change in incompatible ways.
6564** If this is a problem for you, do not use the interface at this time.
6565**
6566** When the virtual-table mechanism stabilizes, we will declare the
6567** interface fixed, support it indefinitely, and remove this comment.
6568*/
6569
6570/*
6571** Structures used by the virtual table interface
6572*/
6573typedef struct sqlite3_vtab sqlite3_vtab;
6574typedef struct sqlite3_index_info sqlite3_index_info;
6575typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
6576typedef struct sqlite3_module sqlite3_module;
6577
6578/*
6579** CAPI3REF: Virtual Table Object
6580** KEYWORDS: sqlite3_module {virtual table module}
6581**
6582** This structure, sometimes called a "virtual table module",
6583** defines the implementation of a [virtual table].
6584** This structure consists mostly of methods for the module.
6585**
6586** ^A virtual table module is created by filling in a persistent
6587** instance of this structure and passing a pointer to that instance
6588** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
6589** ^The registration remains valid until it is replaced by a different
6590** module or until the [database connection] closes. The content
6591** of this structure must not change while it is registered with
6592** any database connection.
6593*/
6594struct sqlite3_module {
6595 int iVersion;
6596 int (*xCreate)(sqlite3*, void *pAux,
6597 int argc, const char *const*argv,
6598 sqlite3_vtab **ppVTab, char**);
6599 int (*xConnect)(sqlite3*, void *pAux,
6600 int argc, const char *const*argv,
6601 sqlite3_vtab **ppVTab, char**);
6602 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
6603 int (*xDisconnect)(sqlite3_vtab *pVTab);
6604 int (*xDestroy)(sqlite3_vtab *pVTab);
6605 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
6606 int (*xClose)(sqlite3_vtab_cursor*);
6607 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
6608 int argc, sqlite3_value **argv);
6609 int (*xNext)(sqlite3_vtab_cursor*);
6610 int (*xEof)(sqlite3_vtab_cursor*);
6611 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
6612 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
6613 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
6614 int (*xBegin)(sqlite3_vtab *pVTab);
6615 int (*xSync)(sqlite3_vtab *pVTab);
6616 int (*xCommit)(sqlite3_vtab *pVTab);
6617 int (*xRollback)(sqlite3_vtab *pVTab);
6618 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
6619 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
6620 void **ppArg);
6621 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
6622 /* The methods above are in version 1 of the sqlite_module object. Those
6623 ** below are for version 2 and greater. */
6624 int (*xSavepoint)(sqlite3_vtab *pVTab, int);
6625 int (*xRelease)(sqlite3_vtab *pVTab, int);
6626 int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
6627 /* The methods above are in versions 1 and 2 of the sqlite_module object.
6628 ** Those below are for version 3 and greater. */
6629 int (*xShadowName)(const char*);
6630};
6631
6632/*
6633** CAPI3REF: Virtual Table Indexing Information
6634** KEYWORDS: sqlite3_index_info
6635**
6636** The sqlite3_index_info structure and its substructures is used as part
6637** of the [virtual table] interface to
6638** pass information into and receive the reply from the [xBestIndex]
6639** method of a [virtual table module]. The fields under **Inputs** are the
6640** inputs to xBestIndex and are read-only. xBestIndex inserts its
6641** results into the **Outputs** fields.
6642**
6643** ^(The aConstraint[] array records WHERE clause constraints of the form:
6644**
6645** <blockquote>column OP expr</blockquote>
6646**
6647** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^ ^(The particular operator is
6648** stored in aConstraint[].op using one of the
6649** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
6650** ^(The index of the column is stored in
6651** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
6652** expr on the right-hand side can be evaluated (and thus the constraint
6653** is usable) and false if it cannot.)^
6654**
6655** ^The optimizer automatically inverts terms of the form "expr OP column"
6656** and makes other simplifications to the WHERE clause in an attempt to
6657** get as many WHERE clause terms into the form shown above as possible.
6658** ^The aConstraint[] array only reports WHERE clause terms that are
6659** relevant to the particular virtual table being queried.
6660**
6661** ^Information about the ORDER BY clause is stored in aOrderBy[].
6662** ^Each term of aOrderBy records a column of the ORDER BY clause.
6663**
6664** The colUsed field indicates which columns of the virtual table may be
6665** required by the current scan. Virtual table columns are numbered from
6666** zero in the order in which they appear within the CREATE TABLE statement
6667** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
6668** the corresponding bit is set within the colUsed mask if the column may be
6669** required by SQLite. If the table has at least 64 columns and any column
6670** to the right of the first 63 is required, then bit 63 of colUsed is also
6671** set. In other words, column iCol may be required if the expression
6672** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
6673** non-zero.
6674**
6675** The [xBestIndex] method must fill aConstraintUsage[] with information
6676** about what parameters to pass to xFilter. ^If argvIndex>0 then
6677** the right-hand side of the corresponding aConstraint[] is evaluated
6678** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
6679** is true, then the constraint is assumed to be fully handled by the
6680** virtual table and might not be checked again by the byte code.)^ ^(The
6681** aConstraintUsage[].omit flag is an optimization hint. When the omit flag
6682** is left in its default setting of false, the constraint will always be
6683** checked separately in byte code. If the omit flag is change to true, then
6684** the constraint may or may not be checked in byte code. In other words,
6685** when the omit flag is true there is no guarantee that the constraint will
6686** not be checked again using byte code.)^
6687**
6688** ^The idxNum and idxPtr values are recorded and passed into the
6689** [xFilter] method.
6690** ^[sqlite3_free()] is used to free idxPtr if and only if
6691** needToFreeIdxPtr is true.
6692**
6693** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
6694** the correct order to satisfy the ORDER BY clause so that no separate
6695** sorting step is required.
6696**
6697** ^The estimatedCost value is an estimate of the cost of a particular
6698** strategy. A cost of N indicates that the cost of the strategy is similar
6699** to a linear scan of an SQLite table with N rows. A cost of log(N)
6700** indicates that the expense of the operation is similar to that of a
6701** binary search on a unique indexed field of an SQLite table with N rows.
6702**
6703** ^The estimatedRows value is an estimate of the number of rows that
6704** will be returned by the strategy.
6705**
6706** The xBestIndex method may optionally populate the idxFlags field with a
6707** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
6708** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
6709** assumes that the strategy may visit at most one row.
6710**
6711** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
6712** SQLite also assumes that if a call to the xUpdate() method is made as
6713** part of the same statement to delete or update a virtual table row and the
6714** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
6715** any database changes. In other words, if the xUpdate() returns
6716** SQLITE_CONSTRAINT, the database contents must be exactly as they were
6717** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
6718** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
6719** the xUpdate method are automatically rolled back by SQLite.
6720**
6721** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
6722** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
6723** If a virtual table extension is
6724** used with an SQLite version earlier than 3.8.2, the results of attempting
6725** to read or write the estimatedRows field are undefined (but are likely
6726** to include crashing the application). The estimatedRows field should
6727** therefore only be used if [sqlite3_libversion_number()] returns a
6728** value greater than or equal to 3008002. Similarly, the idxFlags field
6729** was added for [version 3.9.0] ([dateof:3.9.0]).
6730** It may therefore only be used if
6731** sqlite3_libversion_number() returns a value greater than or equal to
6732** 3009000.
6733*/
6734struct sqlite3_index_info {
6735 /* Inputs */
6736 int nConstraint; /* Number of entries in aConstraint */
6737 struct sqlite3_index_constraint {
6738 int iColumn; /* Column constrained. -1 for ROWID */
6739 unsigned char op; /* Constraint operator */
6740 unsigned char usable; /* True if this constraint is usable */
6741 int iTermOffset; /* Used internally - xBestIndex should ignore */
6742 } *aConstraint; /* Table of WHERE clause constraints */
6743 int nOrderBy; /* Number of terms in the ORDER BY clause */
6744 struct sqlite3_index_orderby {
6745 int iColumn; /* Column number */
6746 unsigned char desc; /* True for DESC. False for ASC. */
6747 } *aOrderBy; /* The ORDER BY clause */
6748 /* Outputs */
6749 struct sqlite3_index_constraint_usage {
6750 int argvIndex; /* if >0, constraint is part of argv to xFilter */
6751 unsigned char omit; /* Do not code a test for this constraint */
6752 } *aConstraintUsage;
6753 int idxNum; /* Number used to identify the index */
6754 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
6755 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
6756 int orderByConsumed; /* True if output is already ordered */
6757 double estimatedCost; /* Estimated cost of using this index */
6758 /* Fields below are only available in SQLite 3.8.2 and later */
6759 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */
6760 /* Fields below are only available in SQLite 3.9.0 and later */
6761 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */
6762 /* Fields below are only available in SQLite 3.10.0 and later */
6763 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */
6764};
6765
6766/*
6767** CAPI3REF: Virtual Table Scan Flags
6768**
6769** Virtual table implementations are allowed to set the
6770** [sqlite3_index_info].idxFlags field to some combination of
6771** these bits.
6772*/
6773#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */
6774
6775/*
6776** CAPI3REF: Virtual Table Constraint Operator Codes
6777**
6778** These macros define the allowed values for the
6779** [sqlite3_index_info].aConstraint[].op field. Each value represents
6780** an operator that is part of a constraint term in the WHERE clause of
6781** a query that uses a [virtual table].
6782**
6783** ^The left-hand operand of the operator is given by the corresponding
6784** aConstraint[].iColumn field. ^An iColumn of -1 indicates the left-hand
6785** operand is the rowid.
6786** The SQLITE_INDEX_CONSTRAINT_LIMIT and SQLITE_INDEX_CONSTRAINT_OFFSET
6787** operators have no left-hand operand, and so for those operators the
6788** corresponding aConstraint[].iColumn is meaningless and should not be
6789** used.
6790**
6791** All operator values from SQLITE_INDEX_CONSTRAINT_FUNCTION through
6792** value 255 are reserved to represent functions that are overloaded
6793** by the [xFindFunction|xFindFunction method] of the virtual table
6794** implementation.
6795**
6796** The right-hand operands for each constraint might be accessible using
6797** the [sqlite3_vtab_rhs_value()] interface. Usually the right-hand
6798** operand is only available if it appears as a single constant literal
6799** in the input SQL. If the right-hand operand is another column or an
6800** expression (even a constant expression) or a parameter, then the
6801** sqlite3_vtab_rhs_value() probably will not be able to extract it.
6802** ^The SQLITE_INDEX_CONSTRAINT_ISNULL and
6803** SQLITE_INDEX_CONSTRAINT_ISNOTNULL operators have no right-hand operand
6804** and hence calls to sqlite3_vtab_rhs_value() for those operators will
6805** always return SQLITE_NOTFOUND.
6806**
6807** The collating sequence to be used for comparison can be found using
6808** the [sqlite3_vtab_collation()] interface. For most real-world virtual
6809** tables, the collating sequence of constraints does not matter (for example
6810** because the constraints are numeric) and so the sqlite3_vtab_collation()
6811** interface is no commonly needed.
6812*/
6813#define SQLITE_INDEX_CONSTRAINT_EQ 2
6814#define SQLITE_INDEX_CONSTRAINT_GT 4
6815#define SQLITE_INDEX_CONSTRAINT_LE 8
6816#define SQLITE_INDEX_CONSTRAINT_LT 16
6817#define SQLITE_INDEX_CONSTRAINT_GE 32
6818#define SQLITE_INDEX_CONSTRAINT_MATCH 64
6819#define SQLITE_INDEX_CONSTRAINT_LIKE 65
6820#define SQLITE_INDEX_CONSTRAINT_GLOB 66
6821#define SQLITE_INDEX_CONSTRAINT_REGEXP 67
6822#define SQLITE_INDEX_CONSTRAINT_NE 68
6823#define SQLITE_INDEX_CONSTRAINT_ISNOT 69
6824#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70
6825#define SQLITE_INDEX_CONSTRAINT_ISNULL 71
6826#define SQLITE_INDEX_CONSTRAINT_IS 72
6827#define SQLITE_INDEX_CONSTRAINT_LIMIT 73
6828#define SQLITE_INDEX_CONSTRAINT_OFFSET 74
6829#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150
6830
6831/*
6832** CAPI3REF: Register A Virtual Table Implementation
6833** METHOD: sqlite3
6834**
6835** ^These routines are used to register a new [virtual table module] name.
6836** ^Module names must be registered before
6837** creating a new [virtual table] using the module and before using a
6838** preexisting [virtual table] for the module.
6839**
6840** ^The module name is registered on the [database connection] specified
6841** by the first parameter. ^The name of the module is given by the
6842** second parameter. ^The third parameter is a pointer to
6843** the implementation of the [virtual table module]. ^The fourth
6844** parameter is an arbitrary client data pointer that is passed through
6845** into the [xCreate] and [xConnect] methods of the virtual table module
6846** when a new virtual table is be being created or reinitialized.
6847**
6848** ^The sqlite3_create_module_v2() interface has a fifth parameter which
6849** is a pointer to a destructor for the pClientData. ^SQLite will
6850** invoke the destructor function (if it is not NULL) when SQLite
6851** no longer needs the pClientData pointer. ^The destructor will also
6852** be invoked if the call to sqlite3_create_module_v2() fails.
6853** ^The sqlite3_create_module()
6854** interface is equivalent to sqlite3_create_module_v2() with a NULL
6855** destructor.
6856**
6857** ^If the third parameter (the pointer to the sqlite3_module object) is
6858** NULL then no new module is created and any existing modules with the
6859** same name are dropped.
6860**
6861** See also: [sqlite3_drop_modules()]
6862*/
6863
6864/*
6865** CAPI3REF: Remove Unnecessary Virtual Table Implementations
6866** METHOD: sqlite3
6867**
6868** ^The sqlite3_drop_modules(D,L) interface removes all virtual
6869** table modules from database connection D except those named on list L.
6870** The L parameter must be either NULL or a pointer to an array of pointers
6871** to strings where the array is terminated by a single NULL pointer.
6872** ^If the L parameter is NULL, then all virtual table modules are removed.
6873**
6874** See also: [sqlite3_create_module()]
6875*/
6876
6877/*
6878** CAPI3REF: Virtual Table Instance Object
6879** KEYWORDS: sqlite3_vtab
6880**
6881** Every [virtual table module] implementation uses a subclass
6882** of this object to describe a particular instance
6883** of the [virtual table]. Each subclass will
6884** be tailored to the specific needs of the module implementation.
6885** The purpose of this superclass is to define certain fields that are
6886** common to all module implementations.
6887**
6888** ^Virtual tables methods can set an error message by assigning a
6889** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
6890** take care that any prior string is freed by a call to [sqlite3_free()]
6891** prior to assigning a new string to zErrMsg. ^After the error message
6892** is delivered up to the client application, the string will be automatically
6893** freed by sqlite3_free() and the zErrMsg field will be zeroed.
6894*/
6895struct sqlite3_vtab {
6896 const sqlite3_module *pModule; /* The module for this virtual table */
6897 int nRef; /* Number of open cursors */
6898 char *zErrMsg; /* Error message from sqlite3_mprintf() */
6899 /* Virtual table implementations will typically add additional fields */
6900};
6901
6902/*
6903** CAPI3REF: Virtual Table Cursor Object
6904** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
6905**
6906** Every [virtual table module] implementation uses a subclass of the
6907** following structure to describe cursors that point into the
6908** [virtual table] and are used
6909** to loop through the virtual table. Cursors are created using the
6910** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
6911** by the [sqlite3_module.xClose | xClose] method. Cursors are used
6912** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
6913** of the module. Each module implementation will define
6914** the content of a cursor structure to suit its own needs.
6915**
6916** This superclass exists in order to define fields of the cursor that
6917** are common to all implementations.
6918*/
6919struct sqlite3_vtab_cursor {
6920 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
6921 /* Virtual table implementations will typically add additional fields */
6922};
6923
6924/*
6925** CAPI3REF: Declare The Schema Of A Virtual Table
6926**
6927** ^The [xCreate] and [xConnect] methods of a
6928** [virtual table module] call this interface
6929** to declare the format (the names and datatypes of the columns) of
6930** the virtual tables they implement.
6931*/
6932
6933/*
6934** CAPI3REF: Overload A Function For A Virtual Table
6935** METHOD: sqlite3
6936**
6937** ^(Virtual tables can provide alternative implementations of functions
6938** using the [xFindFunction] method of the [virtual table module].
6939** But global versions of those functions
6940** must exist in order to be overloaded.)^
6941**
6942** ^(This API makes sure a global version of a function with a particular
6943** name and number of parameters exists. If no such function exists
6944** before this API is called, a new function is created.)^ ^The implementation
6945** of the new function always causes an exception to be thrown. So
6946** the new function is not good for anything by itself. Its only
6947** purpose is to be a placeholder function that can be overloaded
6948** by a [virtual table].
6949*/
6950
6951/*
6952** The interface to the virtual-table mechanism defined above (back up
6953** to a comment remarkably similar to this one) is currently considered
6954** to be experimental. The interface might change in incompatible ways.
6955** If this is a problem for you, do not use the interface at this time.
6956**
6957** When the virtual-table mechanism stabilizes, we will declare the
6958** interface fixed, support it indefinitely, and remove this comment.
6959*/
6960
6961/*
6962** CAPI3REF: A Handle To An Open BLOB
6963** KEYWORDS: {BLOB handle} {BLOB handles}
6964**
6965** An instance of this object represents an open BLOB on which
6966** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
6967** ^Objects of this type are created by [sqlite3_blob_open()]
6968** and destroyed by [sqlite3_blob_close()].
6969** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
6970** can be used to read or write small subsections of the BLOB.
6971** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
6972*/
6973typedef struct sqlite3_blob sqlite3_blob;
6974
6975/*
6976** CAPI3REF: Open A BLOB For Incremental I/O
6977** METHOD: sqlite3
6978** CONSTRUCTOR: sqlite3_blob
6979**
6980** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
6981** in row iRow, column zColumn, table zTable in database zDb;
6982** in other words, the same BLOB that would be selected by:
6983**
6984** <pre>
6985** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
6986** </pre>)^
6987**
6988** ^(Parameter zDb is not the filename that contains the database, but
6989** rather the symbolic name of the database. For attached databases, this is
6990** the name that appears after the AS keyword in the [ATTACH] statement.
6991** For the main database file, the database name is "main". For TEMP
6992** tables, the database name is "temp".)^
6993**
6994** ^If the flags parameter is non-zero, then the BLOB is opened for read
6995** and write access. ^If the flags parameter is zero, the BLOB is opened for
6996** read-only access.
6997**
6998** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
6999** in *ppBlob. Otherwise an [error code] is returned and, unless the error
7000** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
7001** the API is not misused, it is always safe to call [sqlite3_blob_close()]
7002** on *ppBlob after this function it returns.
7003**
7004** This function fails with SQLITE_ERROR if any of the following are true:
7005** <ul>
7006** <li> ^(Database zDb does not exist)^,
7007** <li> ^(Table zTable does not exist within database zDb)^,
7008** <li> ^(Table zTable is a WITHOUT ROWID table)^,
7009** <li> ^(Column zColumn does not exist)^,
7010** <li> ^(Row iRow is not present in the table)^,
7011** <li> ^(The specified column of row iRow contains a value that is not
7012** a TEXT or BLOB value)^,
7013** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
7014** constraint and the blob is being opened for read/write access)^,
7015** <li> ^([foreign key constraints | Foreign key constraints] are enabled,
7016** column zColumn is part of a [child key] definition and the blob is
7017** being opened for read/write access)^.
7018** </ul>
7019**
7020** ^Unless it returns SQLITE_MISUSE, this function sets the
7021** [database connection] error code and message accessible via
7022** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
7023**
7024** A BLOB referenced by sqlite3_blob_open() may be read using the
7025** [sqlite3_blob_read()] interface and modified by using
7026** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a
7027** different row of the same table using the [sqlite3_blob_reopen()]
7028** interface. However, the column, table, or database of a [BLOB handle]
7029** cannot be changed after the [BLOB handle] is opened.
7030**
7031** ^(If the row that a BLOB handle points to is modified by an
7032** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
7033** then the BLOB handle is marked as "expired".
7034** This is true if any column of the row is changed, even a column
7035** other than the one the BLOB handle is open on.)^
7036** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
7037** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
7038** ^(Changes written into a BLOB prior to the BLOB expiring are not
7039** rolled back by the expiration of the BLOB. Such changes will eventually
7040** commit if the transaction continues to completion.)^
7041**
7042** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
7043** the opened blob. ^The size of a blob may not be changed by this
7044** interface. Use the [UPDATE] SQL command to change the size of a
7045** blob.
7046**
7047** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
7048** and the built-in [zeroblob] SQL function may be used to create a
7049** zero-filled blob to read or write using the incremental-blob interface.
7050**
7051** To avoid a resource leak, every open [BLOB handle] should eventually
7052** be released by a call to [sqlite3_blob_close()].
7053**
7054** See also: [sqlite3_blob_close()],
7055** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
7056** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
7057*/
7058
7059/*
7060** CAPI3REF: Move a BLOB Handle to a New Row
7061** METHOD: sqlite3_blob
7062**
7063** ^This function is used to move an existing [BLOB handle] so that it points
7064** to a different row of the same database table. ^The new row is identified
7065** by the rowid value passed as the second argument. Only the row can be
7066** changed. ^The database, table and column on which the blob handle is open
7067** remain the same. Moving an existing [BLOB handle] to a new row is
7068** faster than closing the existing handle and opening a new one.
7069**
7070** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
7071** it must exist and there must be either a blob or text value stored in
7072** the nominated column.)^ ^If the new row is not present in the table, or if
7073** it does not contain a blob or text value, or if another error occurs, an
7074** SQLite error code is returned and the blob handle is considered aborted.
7075** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
7076** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
7077** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
7078** always returns zero.
7079**
7080** ^This function sets the database handle error code and message.
7081*/
7082
7083/*
7084** CAPI3REF: Close A BLOB Handle
7085** DESTRUCTOR: sqlite3_blob
7086**
7087** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
7088** unconditionally. Even if this routine returns an error code, the
7089** handle is still closed.)^
7090**
7091** ^If the blob handle being closed was opened for read-write access, and if
7092** the database is in auto-commit mode and there are no other open read-write
7093** blob handles or active write statements, the current transaction is
7094** committed. ^If an error occurs while committing the transaction, an error
7095** code is returned and the transaction rolled back.
7096**
7097** Calling this function with an argument that is not a NULL pointer or an
7098** open blob handle results in undefined behaviour. ^Calling this routine
7099** with a null pointer (such as would be returned by a failed call to
7100** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
7101** is passed a valid open blob handle, the values returned by the
7102** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
7103*/
7104
7105/*
7106** CAPI3REF: Return The Size Of An Open BLOB
7107** METHOD: sqlite3_blob
7108**
7109** ^Returns the size in bytes of the BLOB accessible via the
7110** successfully opened [BLOB handle] in its only argument. ^The
7111** incremental blob I/O routines can only read or overwriting existing
7112** blob content; they cannot change the size of a blob.
7113**
7114** This routine only works on a [BLOB handle] which has been created
7115** by a prior successful call to [sqlite3_blob_open()] and which has not
7116** been closed by [sqlite3_blob_close()]. Passing any other pointer in
7117** to this routine results in undefined and probably undesirable behavior.
7118*/
7119
7120/*
7121** CAPI3REF: Read Data From A BLOB Incrementally
7122** METHOD: sqlite3_blob
7123**
7124** ^(This function is used to read data from an open [BLOB handle] into a
7125** caller-supplied buffer. N bytes of data are copied into buffer Z
7126** from the open BLOB, starting at offset iOffset.)^
7127**
7128** ^If offset iOffset is less than N bytes from the end of the BLOB,
7129** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
7130** less than zero, [SQLITE_ERROR] is returned and no data is read.
7131** ^The size of the blob (and hence the maximum value of N+iOffset)
7132** can be determined using the [sqlite3_blob_bytes()] interface.
7133**
7134** ^An attempt to read from an expired [BLOB handle] fails with an
7135** error code of [SQLITE_ABORT].
7136**
7137** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
7138** Otherwise, an [error code] or an [extended error code] is returned.)^
7139**
7140** This routine only works on a [BLOB handle] which has been created
7141** by a prior successful call to [sqlite3_blob_open()] and which has not
7142** been closed by [sqlite3_blob_close()]. Passing any other pointer in
7143** to this routine results in undefined and probably undesirable behavior.
7144**
7145** See also: [sqlite3_blob_write()].
7146*/
7147
7148/*
7149** CAPI3REF: Write Data Into A BLOB Incrementally
7150** METHOD: sqlite3_blob
7151**
7152** ^(This function is used to write data into an open [BLOB handle] from a
7153** caller-supplied buffer. N bytes of data are copied from the buffer Z
7154** into the open BLOB, starting at offset iOffset.)^
7155**
7156** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
7157** Otherwise, an [error code] or an [extended error code] is returned.)^
7158** ^Unless SQLITE_MISUSE is returned, this function sets the
7159** [database connection] error code and message accessible via
7160** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
7161**
7162** ^If the [BLOB handle] passed as the first argument was not opened for
7163** writing (the flags parameter to [sqlite3_blob_open()] was zero),
7164** this function returns [SQLITE_READONLY].
7165**
7166** This function may only modify the contents of the BLOB; it is
7167** not possible to increase the size of a BLOB using this API.
7168** ^If offset iOffset is less than N bytes from the end of the BLOB,
7169** [SQLITE_ERROR] is returned and no data is written. The size of the
7170** BLOB (and hence the maximum value of N+iOffset) can be determined
7171** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
7172** than zero [SQLITE_ERROR] is returned and no data is written.
7173**
7174** ^An attempt to write to an expired [BLOB handle] fails with an
7175** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
7176** before the [BLOB handle] expired are not rolled back by the
7177** expiration of the handle, though of course those changes might
7178** have been overwritten by the statement that expired the BLOB handle
7179** or by other independent statements.
7180**
7181** This routine only works on a [BLOB handle] which has been created
7182** by a prior successful call to [sqlite3_blob_open()] and which has not
7183** been closed by [sqlite3_blob_close()]. Passing any other pointer in
7184** to this routine results in undefined and probably undesirable behavior.
7185**
7186** See also: [sqlite3_blob_read()].
7187*/
7188
7189/*
7190** CAPI3REF: Virtual File System Objects
7191**
7192** A virtual filesystem (VFS) is an [sqlite3_vfs] object
7193** that SQLite uses to interact
7194** with the underlying operating system. Most SQLite builds come with a
7195** single default VFS that is appropriate for the host computer.
7196** New VFSes can be registered and existing VFSes can be unregistered.
7197** The following interfaces are provided.
7198**
7199** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
7200** ^Names are case sensitive.
7201** ^Names are zero-terminated UTF-8 strings.
7202** ^If there is no match, a NULL pointer is returned.
7203** ^If zVfsName is NULL then the default VFS is returned.
7204**
7205** ^New VFSes are registered with sqlite3_vfs_register().
7206** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
7207** ^The same VFS can be registered multiple times without injury.
7208** ^To make an existing VFS into the default VFS, register it again
7209** with the makeDflt flag set. If two different VFSes with the
7210** same name are registered, the behavior is undefined. If a
7211** VFS is registered with a name that is NULL or an empty string,
7212** then the behavior is undefined.
7213**
7214** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
7215** ^(If the default VFS is unregistered, another VFS is chosen as
7216** the default. The choice for the new VFS is arbitrary.)^
7217*/
7218
7219/*
7220** CAPI3REF: Mutexes
7221**
7222** The SQLite core uses these routines for thread
7223** synchronization. Though they are intended for internal
7224** use by SQLite, code that links against SQLite is
7225** permitted to use any of these routines.
7226**
7227** The SQLite source code contains multiple implementations
7228** of these mutex routines. An appropriate implementation
7229** is selected automatically at compile-time. The following
7230** implementations are available in the SQLite core:
7231**
7232** <ul>
7233** <li> SQLITE_MUTEX_PTHREADS
7234** <li> SQLITE_MUTEX_W32
7235** <li> SQLITE_MUTEX_NOOP
7236** </ul>
7237**
7238** The SQLITE_MUTEX_NOOP implementation is a set of routines
7239** that does no real locking and is appropriate for use in
7240** a single-threaded application. The SQLITE_MUTEX_PTHREADS and
7241** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
7242** and Windows.
7243**
7244** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
7245** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
7246** implementation is included with the library. In this case the
7247** application must supply a custom mutex implementation using the
7248** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
7249** before calling sqlite3_initialize() or any other public sqlite3_
7250** function that calls sqlite3_initialize().
7251**
7252** ^The sqlite3_mutex_alloc() routine allocates a new
7253** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
7254** routine returns NULL if it is unable to allocate the requested
7255** mutex. The argument to sqlite3_mutex_alloc() must one of these
7256** integer constants:
7257**
7258** <ul>
7259** <li> SQLITE_MUTEX_FAST
7260** <li> SQLITE_MUTEX_RECURSIVE
7261** <li> SQLITE_MUTEX_STATIC_MAIN
7262** <li> SQLITE_MUTEX_STATIC_MEM
7263** <li> SQLITE_MUTEX_STATIC_OPEN
7264** <li> SQLITE_MUTEX_STATIC_PRNG
7265** <li> SQLITE_MUTEX_STATIC_LRU
7266** <li> SQLITE_MUTEX_STATIC_PMEM
7267** <li> SQLITE_MUTEX_STATIC_APP1
7268** <li> SQLITE_MUTEX_STATIC_APP2
7269** <li> SQLITE_MUTEX_STATIC_APP3
7270** <li> SQLITE_MUTEX_STATIC_VFS1
7271** <li> SQLITE_MUTEX_STATIC_VFS2
7272** <li> SQLITE_MUTEX_STATIC_VFS3
7273** </ul>
7274**
7275** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
7276** cause sqlite3_mutex_alloc() to create
7277** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
7278** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
7279** The mutex implementation does not need to make a distinction
7280** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
7281** not want to. SQLite will only request a recursive mutex in
7282** cases where it really needs one. If a faster non-recursive mutex
7283** implementation is available on the host platform, the mutex subsystem
7284** might return such a mutex in response to SQLITE_MUTEX_FAST.
7285**
7286** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
7287** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
7288** a pointer to a static preexisting mutex. ^Nine static mutexes are
7289** used by the current version of SQLite. Future versions of SQLite
7290** may add additional static mutexes. Static mutexes are for internal
7291** use by SQLite only. Applications that use SQLite mutexes should
7292** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
7293** SQLITE_MUTEX_RECURSIVE.
7294**
7295** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
7296** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
7297** returns a different mutex on every call. ^For the static
7298** mutex types, the same mutex is returned on every call that has
7299** the same type number.
7300**
7301** ^The sqlite3_mutex_free() routine deallocates a previously
7302** allocated dynamic mutex. Attempting to deallocate a static
7303** mutex results in undefined behavior.
7304**
7305** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
7306** to enter a mutex. ^If another thread is already within the mutex,
7307** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
7308** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
7309** upon successful entry. ^(Mutexes created using
7310** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
7311** In such cases, the
7312** mutex must be exited an equal number of times before another thread
7313** can enter.)^ If the same thread tries to enter any mutex other
7314** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
7315**
7316** ^(Some systems (for example, Windows 95) do not support the operation
7317** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
7318** will always return SQLITE_BUSY. The SQLite core only ever uses
7319** sqlite3_mutex_try() as an optimization so this is acceptable
7320** behavior.)^
7321**
7322** ^The sqlite3_mutex_leave() routine exits a mutex that was
7323** previously entered by the same thread. The behavior
7324** is undefined if the mutex is not currently entered by the
7325** calling thread or is not currently allocated.
7326**
7327** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
7328** sqlite3_mutex_leave() is a NULL pointer, then all three routines
7329** behave as no-ops.
7330**
7331** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
7332*/
7333
7334/*
7335** CAPI3REF: Mutex Methods Object
7336**
7337** An instance of this structure defines the low-level routines
7338** used to allocate and use mutexes.
7339**
7340** Usually, the default mutex implementations provided by SQLite are
7341** sufficient, however the application has the option of substituting a custom
7342** implementation for specialized deployments or systems for which SQLite
7343** does not provide a suitable implementation. In this case, the application
7344** creates and populates an instance of this structure to pass
7345** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
7346** Additionally, an instance of this structure can be used as an
7347** output variable when querying the system for the current mutex
7348** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
7349**
7350** ^The xMutexInit method defined by this structure is invoked as
7351** part of system initialization by the sqlite3_initialize() function.
7352** ^The xMutexInit routine is called by SQLite exactly once for each
7353** effective call to [sqlite3_initialize()].
7354**
7355** ^The xMutexEnd method defined by this structure is invoked as
7356** part of system shutdown by the sqlite3_shutdown() function. The
7357** implementation of this method is expected to release all outstanding
7358** resources obtained by the mutex methods implementation, especially
7359** those obtained by the xMutexInit method. ^The xMutexEnd()
7360** interface is invoked exactly once for each call to [sqlite3_shutdown()].
7361**
7362** ^(The remaining seven methods defined by this structure (xMutexAlloc,
7363** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
7364** xMutexNotheld) implement the following interfaces (respectively):
7365**
7366** <ul>
7367** <li> [sqlite3_mutex_alloc()] </li>
7368** <li> [sqlite3_mutex_free()] </li>
7369** <li> [sqlite3_mutex_enter()] </li>
7370** <li> [sqlite3_mutex_try()] </li>
7371** <li> [sqlite3_mutex_leave()] </li>
7372** <li> [sqlite3_mutex_held()] </li>
7373** <li> [sqlite3_mutex_notheld()] </li>
7374** </ul>)^
7375**
7376** The only difference is that the public sqlite3_XXX functions enumerated
7377** above silently ignore any invocations that pass a NULL pointer instead
7378** of a valid mutex handle. The implementations of the methods defined
7379** by this structure are not required to handle this case. The results
7380** of passing a NULL pointer instead of a valid mutex handle are undefined
7381** (i.e. it is acceptable to provide an implementation that segfaults if
7382** it is passed a NULL pointer).
7383**
7384** The xMutexInit() method must be threadsafe. It must be harmless to
7385** invoke xMutexInit() multiple times within the same process and without
7386** intervening calls to xMutexEnd(). Second and subsequent calls to
7387** xMutexInit() must be no-ops.
7388**
7389** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
7390** and its associates). Similarly, xMutexAlloc() must not use SQLite memory
7391** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
7392** memory allocation for a fast or recursive mutex.
7393**
7394** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
7395** called, but only if the prior call to xMutexInit returned SQLITE_OK.
7396** If xMutexInit fails in any way, it is expected to clean up after itself
7397** prior to returning.
7398*/
7399typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
7400struct sqlite3_mutex_methods {
7401 int (*xMutexInit)(void);
7402 int (*xMutexEnd)(void);
7403 sqlite3_mutex *(*xMutexAlloc)(int);
7404 void (*xMutexFree)(sqlite3_mutex *);
7405 void (*xMutexEnter)(sqlite3_mutex *);
7406 int (*xMutexTry)(sqlite3_mutex *);
7407 void (*xMutexLeave)(sqlite3_mutex *);
7408 int (*xMutexHeld)(sqlite3_mutex *);
7409 int (*xMutexNotheld)(sqlite3_mutex *);
7410};
7411
7412/*
7413** CAPI3REF: Mutex Verification Routines
7414**
7415** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
7416** are intended for use inside assert() statements. The SQLite core
7417** never uses these routines except inside an assert() and applications
7418** are advised to follow the lead of the core. The SQLite core only
7419** provides implementations for these routines when it is compiled
7420** with the SQLITE_DEBUG flag. External mutex implementations
7421** are only required to provide these routines if SQLITE_DEBUG is
7422** defined and if NDEBUG is not defined.
7423**
7424** These routines should return true if the mutex in their argument
7425** is held or not held, respectively, by the calling thread.
7426**
7427** The implementation is not required to provide versions of these
7428** routines that actually work. If the implementation does not provide working
7429** versions of these routines, it should at least provide stubs that always
7430** return true so that one does not get spurious assertion failures.
7431**
7432** If the argument to sqlite3_mutex_held() is a NULL pointer then
7433** the routine should return 1. This seems counter-intuitive since
7434** clearly the mutex cannot be held if it does not exist. But
7435** the reason the mutex does not exist is because the build is not
7436** using mutexes. And we do not want the assert() containing the
7437** call to sqlite3_mutex_held() to fail, so a non-zero return is
7438** the appropriate thing to do. The sqlite3_mutex_notheld()
7439** interface should also return 1 when given a NULL pointer.
7440*/
7441#ifndef NDEBUG
7442#endif
7443
7444/*
7445** CAPI3REF: Mutex Types
7446**
7447** The [sqlite3_mutex_alloc()] interface takes a single argument
7448** which is one of these integer constants.
7449**
7450** The set of static mutexes may change from one SQLite release to the
7451** next. Applications that override the built-in mutex logic must be
7452** prepared to accommodate additional static mutexes.
7453*/
7454#define SQLITE_MUTEX_FAST 0
7455#define SQLITE_MUTEX_RECURSIVE 1
7456#define SQLITE_MUTEX_STATIC_MAIN 2
7457#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
7458#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
7459#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
7460#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */
7461#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
7462#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
7463#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
7464#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */
7465#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */
7466#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */
7467#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */
7468#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */
7469#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */
7470
7471/* Legacy compatibility: */
7472#define SQLITE_MUTEX_STATIC_MASTER 2
7473
7474
7475/*
7476** CAPI3REF: Retrieve the mutex for a database connection
7477** METHOD: sqlite3
7478**
7479** ^This interface returns a pointer the [sqlite3_mutex] object that
7480** serializes access to the [database connection] given in the argument
7481** when the [threading mode] is Serialized.
7482** ^If the [threading mode] is Single-thread or Multi-thread then this
7483** routine returns a NULL pointer.
7484*/
7485
7486/*
7487** CAPI3REF: Low-Level Control Of Database Files
7488** METHOD: sqlite3
7489** KEYWORDS: {file control}
7490**
7491** ^The [sqlite3_file_control()] interface makes a direct call to the
7492** xFileControl method for the [sqlite3_io_methods] object associated
7493** with a particular database identified by the second argument. ^The
7494** name of the database is "main" for the main database or "temp" for the
7495** TEMP database, or the name that appears after the AS keyword for
7496** databases that are added using the [ATTACH] SQL command.
7497** ^A NULL pointer can be used in place of "main" to refer to the
7498** main database file.
7499** ^The third and fourth parameters to this routine
7500** are passed directly through to the second and third parameters of
7501** the xFileControl method. ^The return value of the xFileControl
7502** method becomes the return value of this routine.
7503**
7504** A few opcodes for [sqlite3_file_control()] are handled directly
7505** by the SQLite core and never invoke the
7506** sqlite3_io_methods.xFileControl method.
7507** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
7508** a pointer to the underlying [sqlite3_file] object to be written into
7509** the space pointed to by the 4th parameter. The
7510** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns
7511** the [sqlite3_file] object associated with the journal file instead of
7512** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns
7513** a pointer to the underlying [sqlite3_vfs] object for the file.
7514** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter
7515** from the pager.
7516**
7517** ^If the second parameter (zDbName) does not match the name of any
7518** open database file, then SQLITE_ERROR is returned. ^This error
7519** code is not remembered and will not be recalled by [sqlite3_errcode()]
7520** or [sqlite3_errmsg()]. The underlying xFileControl method might
7521** also return SQLITE_ERROR. There is no way to distinguish between
7522** an incorrect zDbName and an SQLITE_ERROR return from the underlying
7523** xFileControl method.
7524**
7525** See also: [file control opcodes]
7526*/
7527
7528/*
7529** CAPI3REF: Testing Interface
7530**
7531** ^The sqlite3_test_control() interface is used to read out internal
7532** state of SQLite and to inject faults into SQLite for testing
7533** purposes. ^The first parameter is an operation code that determines
7534** the number, meaning, and operation of all subsequent parameters.
7535**
7536** This interface is not for use by applications. It exists solely
7537** for verifying the correct operation of the SQLite library. Depending
7538** on how the SQLite library is compiled, this interface might not exist.
7539**
7540** The details of the operation codes, their meanings, the parameters
7541** they take, and what they do are all subject to change without notice.
7542** Unlike most of the SQLite API, this function is not guaranteed to
7543** operate consistently from one release to the next.
7544*/
7545
7546/*
7547** CAPI3REF: Testing Interface Operation Codes
7548**
7549** These constants are the valid operation code parameters used
7550** as the first argument to [sqlite3_test_control()].
7551**
7552** These parameters and their meanings are subject to change
7553** without notice. These values are for testing purposes only.
7554** Applications should not use any of these parameters or the
7555** [sqlite3_test_control()] interface.
7556*/
7557#define SQLITE_TESTCTRL_FIRST 5
7558#define SQLITE_TESTCTRL_PRNG_SAVE 5
7559#define SQLITE_TESTCTRL_PRNG_RESTORE 6
7560#define SQLITE_TESTCTRL_PRNG_RESET 7 /* NOT USED */
7561#define SQLITE_TESTCTRL_BITVEC_TEST 8
7562#define SQLITE_TESTCTRL_FAULT_INSTALL 9
7563#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
7564#define SQLITE_TESTCTRL_PENDING_BYTE 11
7565#define SQLITE_TESTCTRL_ASSERT 12
7566#define SQLITE_TESTCTRL_ALWAYS 13
7567#define SQLITE_TESTCTRL_RESERVE 14 /* NOT USED */
7568#define SQLITE_TESTCTRL_OPTIMIZATIONS 15
7569#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */
7570#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */
7571#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17
7572#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
7573#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */
7574#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19
7575#define SQLITE_TESTCTRL_NEVER_CORRUPT 20
7576#define SQLITE_TESTCTRL_VDBE_COVERAGE 21
7577#define SQLITE_TESTCTRL_BYTEORDER 22
7578#define SQLITE_TESTCTRL_ISINIT 23
7579#define SQLITE_TESTCTRL_SORTER_MMAP 24
7580#define SQLITE_TESTCTRL_IMPOSTER 25
7581#define SQLITE_TESTCTRL_PARSER_COVERAGE 26
7582#define SQLITE_TESTCTRL_RESULT_INTREAL 27
7583#define SQLITE_TESTCTRL_PRNG_SEED 28
7584#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS 29
7585#define SQLITE_TESTCTRL_SEEK_COUNT 30
7586#define SQLITE_TESTCTRL_TRACEFLAGS 31
7587#define SQLITE_TESTCTRL_TUNE 32
7588#define SQLITE_TESTCTRL_LOGEST 33
7589#define SQLITE_TESTCTRL_LAST 33 /* Largest TESTCTRL */
7590
7591/*
7592** CAPI3REF: SQL Keyword Checking
7593**
7594** These routines provide access to the set of SQL language keywords
7595** recognized by SQLite. Applications can uses these routines to determine
7596** whether or not a specific identifier needs to be escaped (for example,
7597** by enclosing in double-quotes) so as not to confuse the parser.
7598**
7599** The sqlite3_keyword_count() interface returns the number of distinct
7600** keywords understood by SQLite.
7601**
7602** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and
7603** makes *Z point to that keyword expressed as UTF8 and writes the number
7604** of bytes in the keyword into *L. The string that *Z points to is not
7605** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns
7606** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
7607** or L are NULL or invalid pointers then calls to
7608** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
7609**
7610** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
7611** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
7612** if it is and zero if not.
7613**
7614** The parser used by SQLite is forgiving. It is often possible to use
7615** a keyword as an identifier as long as such use does not result in a
7616** parsing ambiguity. For example, the statement
7617** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
7618** creates a new table named "BEGIN" with three columns named
7619** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid
7620** using keywords as identifiers. Common techniques used to avoid keyword
7621** name collisions include:
7622** <ul>
7623** <li> Put all identifier names inside double-quotes. This is the official
7624** SQL way to escape identifier names.
7625** <li> Put identifier names inside &#91;...&#93;. This is not standard SQL,
7626** but it is what SQL Server does and so lots of programmers use this
7627** technique.
7628** <li> Begin every identifier with the letter "Z" as no SQL keywords start
7629** with "Z".
7630** <li> Include a digit somewhere in every identifier name.
7631** </ul>
7632**
7633** Note that the number of keywords understood by SQLite can depend on
7634** compile-time options. For example, "VACUUM" is not a keyword if
7635** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also,
7636** new keywords may be added to future releases of SQLite.
7637*/
7638
7639/*
7640** CAPI3REF: Dynamic String Object
7641** KEYWORDS: {dynamic string}
7642**
7643** An instance of the sqlite3_str object contains a dynamically-sized
7644** string under construction.
7645**
7646** The lifecycle of an sqlite3_str object is as follows:
7647** <ol>
7648** <li> ^The sqlite3_str object is created using [sqlite3_str_new()].
7649** <li> ^Text is appended to the sqlite3_str object using various
7650** methods, such as [sqlite3_str_appendf()].
7651** <li> ^The sqlite3_str object is destroyed and the string it created
7652** is returned using the [sqlite3_str_finish()] interface.
7653** </ol>
7654*/
7655typedef struct sqlite3_str sqlite3_str;
7656
7657/*
7658** CAPI3REF: Create A New Dynamic String Object
7659** CONSTRUCTOR: sqlite3_str
7660**
7661** ^The [sqlite3_str_new(D)] interface allocates and initializes
7662** a new [sqlite3_str] object. To avoid memory leaks, the object returned by
7663** [sqlite3_str_new()] must be freed by a subsequent call to
7664** [sqlite3_str_finish(X)].
7665**
7666** ^The [sqlite3_str_new(D)] interface always returns a pointer to a
7667** valid [sqlite3_str] object, though in the event of an out-of-memory
7668** error the returned object might be a special singleton that will
7669** silently reject new text, always return SQLITE_NOMEM from
7670** [sqlite3_str_errcode()], always return 0 for
7671** [sqlite3_str_length()], and always return NULL from
7672** [sqlite3_str_finish(X)]. It is always safe to use the value
7673** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter
7674** to any of the other [sqlite3_str] methods.
7675**
7676** The D parameter to [sqlite3_str_new(D)] may be NULL. If the
7677** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum
7678** length of the string contained in the [sqlite3_str] object will be
7679** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead
7680** of [SQLITE_MAX_LENGTH].
7681*/
7682
7683/*
7684** CAPI3REF: Finalize A Dynamic String
7685** DESTRUCTOR: sqlite3_str
7686**
7687** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
7688** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
7689** that contains the constructed string. The calling application should
7690** pass the returned value to [sqlite3_free()] to avoid a memory leak.
7691** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
7692** errors were encountered during construction of the string. ^The
7693** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the
7694** string in [sqlite3_str] object X is zero bytes long.
7695*/
7696
7697/*
7698** CAPI3REF: Add Content To A Dynamic String
7699** METHOD: sqlite3_str
7700**
7701** These interfaces add content to an sqlite3_str object previously obtained
7702** from [sqlite3_str_new()].
7703**
7704** ^The [sqlite3_str_appendf(X,F,...)] and
7705** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
7706** functionality of SQLite to append formatted text onto the end of
7707** [sqlite3_str] object X.
7708**
7709** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
7710** onto the end of the [sqlite3_str] object X. N must be non-negative.
7711** S must contain at least N non-zero bytes of content. To append a
7712** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
7713** method instead.
7714**
7715** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of
7716** zero-terminated string S onto the end of [sqlite3_str] object X.
7717**
7718** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
7719** single-byte character C onto the end of [sqlite3_str] object X.
7720** ^This method can be used, for example, to add whitespace indentation.
7721**
7722** ^The [sqlite3_str_reset(X)] method resets the string under construction
7723** inside [sqlite3_str] object X back to zero bytes in length.
7724**
7725** These methods do not return a result code. ^If an error occurs, that fact
7726** is recorded in the [sqlite3_str] object and can be recovered by a
7727** subsequent call to [sqlite3_str_errcode(X)].
7728*/
7729
7730/*
7731** CAPI3REF: Status Of A Dynamic String
7732** METHOD: sqlite3_str
7733**
7734** These interfaces return the current status of an [sqlite3_str] object.
7735**
7736** ^If any prior errors have occurred while constructing the dynamic string
7737** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
7738** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns
7739** [SQLITE_NOMEM] following any out-of-memory error, or
7740** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
7741** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
7742**
7743** ^The [sqlite3_str_length(X)] method returns the current length, in bytes,
7744** of the dynamic string under construction in [sqlite3_str] object X.
7745** ^The length returned by [sqlite3_str_length(X)] does not include the
7746** zero-termination byte.
7747**
7748** ^The [sqlite3_str_value(X)] method returns a pointer to the current
7749** content of the dynamic string under construction in X. The value
7750** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
7751** and might be freed or altered by any subsequent method on the same
7752** [sqlite3_str] object. Applications must not used the pointer returned
7753** [sqlite3_str_value(X)] after any subsequent method call on the same
7754** object. ^Applications may change the content of the string returned
7755** by [sqlite3_str_value(X)] as long as they do not write into any bytes
7756** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
7757** write any byte after any subsequent sqlite3_str method call.
7758*/
7759
7760/*
7761** CAPI3REF: SQLite Runtime Status
7762**
7763** ^These interfaces are used to retrieve runtime status information
7764** about the performance of SQLite, and optionally to reset various
7765** highwater marks. ^The first argument is an integer code for
7766** the specific parameter to measure. ^(Recognized integer codes
7767** are of the form [status parameters | SQLITE_STATUS_...].)^
7768** ^The current value of the parameter is returned into *pCurrent.
7769** ^The highest recorded value is returned in *pHighwater. ^If the
7770** resetFlag is true, then the highest record value is reset after
7771** *pHighwater is written. ^(Some parameters do not record the highest
7772** value. For those parameters
7773** nothing is written into *pHighwater and the resetFlag is ignored.)^
7774** ^(Other parameters record only the highwater mark and not the current
7775** value. For these latter parameters nothing is written into *pCurrent.)^
7776**
7777** ^The sqlite3_status() and sqlite3_status64() routines return
7778** SQLITE_OK on success and a non-zero [error code] on failure.
7779**
7780** If either the current value or the highwater mark is too large to
7781** be represented by a 32-bit integer, then the values returned by
7782** sqlite3_status() are undefined.
7783**
7784** See also: [sqlite3_db_status()]
7785*/
7786
7787
7788/*
7789** CAPI3REF: Status Parameters
7790** KEYWORDS: {status parameters}
7791**
7792** These integer constants designate various run-time status parameters
7793** that can be returned by [sqlite3_status()].
7794**
7795** <dl>
7796** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
7797** <dd>This parameter is the current amount of memory checked out
7798** using [sqlite3_malloc()], either directly or indirectly. The
7799** figure includes calls made to [sqlite3_malloc()] by the application
7800** and internal memory usage by the SQLite library. Auxiliary page-cache
7801** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
7802** this parameter. The amount returned is the sum of the allocation
7803** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
7804**
7805** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
7806** <dd>This parameter records the largest memory allocation request
7807** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
7808** internal equivalents). Only the value returned in the
7809** *pHighwater parameter to [sqlite3_status()] is of interest.
7810** The value written into the *pCurrent parameter is undefined.</dd>)^
7811**
7812** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
7813** <dd>This parameter records the number of separate memory allocations
7814** currently checked out.</dd>)^
7815**
7816** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
7817** <dd>This parameter returns the number of pages used out of the
7818** [pagecache memory allocator] that was configured using
7819** [SQLITE_CONFIG_PAGECACHE]. The
7820** value returned is in pages, not in bytes.</dd>)^
7821**
7822** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
7823** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
7824** <dd>This parameter returns the number of bytes of page cache
7825** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
7826** buffer and where forced to overflow to [sqlite3_malloc()]. The
7827** returned value includes allocations that overflowed because they
7828** where too large (they were larger than the "sz" parameter to
7829** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
7830** no space was left in the page cache.</dd>)^
7831**
7832** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
7833** <dd>This parameter records the largest memory allocation request
7834** handed to the [pagecache memory allocator]. Only the value returned in the
7835** *pHighwater parameter to [sqlite3_status()] is of interest.
7836** The value written into the *pCurrent parameter is undefined.</dd>)^
7837**
7838** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
7839** <dd>No longer used.</dd>
7840**
7841** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
7842** <dd>No longer used.</dd>
7843**
7844** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
7845** <dd>No longer used.</dd>
7846**
7847** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
7848** <dd>The *pHighwater parameter records the deepest parser stack.
7849** The *pCurrent value is undefined. The *pHighwater value is only
7850** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
7851** </dl>
7852**
7853** New status parameters may be added from time to time.
7854*/
7855#define SQLITE_STATUS_MEMORY_USED 0
7856#define SQLITE_STATUS_PAGECACHE_USED 1
7857#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
7858#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */
7859#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */
7860#define SQLITE_STATUS_MALLOC_SIZE 5
7861#define SQLITE_STATUS_PARSER_STACK 6
7862#define SQLITE_STATUS_PAGECACHE_SIZE 7
7863#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */
7864#define SQLITE_STATUS_MALLOC_COUNT 9
7865
7866/*
7867** CAPI3REF: Database Connection Status
7868** METHOD: sqlite3
7869**
7870** ^This interface is used to retrieve runtime status information
7871** about a single [database connection]. ^The first argument is the
7872** database connection object to be interrogated. ^The second argument
7873** is an integer constant, taken from the set of
7874** [SQLITE_DBSTATUS options], that
7875** determines the parameter to interrogate. The set of
7876** [SQLITE_DBSTATUS options] is likely
7877** to grow in future releases of SQLite.
7878**
7879** ^The current value of the requested parameter is written into *pCur
7880** and the highest instantaneous value is written into *pHiwtr. ^If
7881** the resetFlg is true, then the highest instantaneous value is
7882** reset back down to the current value.
7883**
7884** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
7885** non-zero [error code] on failure.
7886**
7887** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
7888*/
7889
7890/*
7891** CAPI3REF: Status Parameters for database connections
7892** KEYWORDS: {SQLITE_DBSTATUS options}
7893**
7894** These constants are the available integer "verbs" that can be passed as
7895** the second argument to the [sqlite3_db_status()] interface.
7896**
7897** New verbs may be added in future releases of SQLite. Existing verbs
7898** might be discontinued. Applications should check the return code from
7899** [sqlite3_db_status()] to make sure that the call worked.
7900** The [sqlite3_db_status()] interface will return a non-zero error code
7901** if a discontinued or unsupported verb is invoked.
7902**
7903** <dl>
7904** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
7905** <dd>This parameter returns the number of lookaside memory slots currently
7906** checked out.</dd>)^
7907**
7908** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
7909** <dd>This parameter returns the number of malloc attempts that were
7910** satisfied using lookaside memory. Only the high-water value is meaningful;
7911** the current value is always zero.)^
7912**
7913** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
7914** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
7915** <dd>This parameter returns the number malloc attempts that might have
7916** been satisfied using lookaside memory but failed due to the amount of
7917** memory requested being larger than the lookaside slot size.
7918** Only the high-water value is meaningful;
7919** the current value is always zero.)^
7920**
7921** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
7922** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
7923** <dd>This parameter returns the number malloc attempts that might have
7924** been satisfied using lookaside memory but failed due to all lookaside
7925** memory already being in use.
7926** Only the high-water value is meaningful;
7927** the current value is always zero.)^
7928**
7929** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
7930** <dd>This parameter returns the approximate number of bytes of heap
7931** memory used by all pager caches associated with the database connection.)^
7932** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
7933**
7934** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
7935** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
7936** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
7937** pager cache is shared between two or more connections the bytes of heap
7938** memory used by that pager cache is divided evenly between the attached
7939** connections.)^ In other words, if none of the pager caches associated
7940** with the database connection are shared, this request returns the same
7941** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
7942** shared, the value returned by this call will be smaller than that returned
7943** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
7944** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
7945**
7946** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
7947** <dd>This parameter returns the approximate number of bytes of heap
7948** memory used to store the schema for all databases associated
7949** with the connection - main, temp, and any [ATTACH]-ed databases.)^
7950** ^The full amount of memory used by the schemas is reported, even if the
7951** schema memory is shared with other database connections due to
7952** [shared cache mode] being enabled.
7953** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
7954**
7955** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
7956** <dd>This parameter returns the approximate number of bytes of heap
7957** and lookaside memory used by all prepared statements associated with
7958** the database connection.)^
7959** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
7960** </dd>
7961**
7962** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
7963** <dd>This parameter returns the number of pager cache hits that have
7964** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
7965** is always 0.
7966** </dd>
7967**
7968** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
7969** <dd>This parameter returns the number of pager cache misses that have
7970** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
7971** is always 0.
7972** </dd>
7973**
7974** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
7975** <dd>This parameter returns the number of dirty cache entries that have
7976** been written to disk. Specifically, the number of pages written to the
7977** wal file in wal mode databases, or the number of pages written to the
7978** database file in rollback mode databases. Any pages written as part of
7979** transaction rollback or database recovery operations are not included.
7980** If an IO or other error occurs while writing a page to disk, the effect
7981** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
7982** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
7983** </dd>
7984**
7985** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
7986** <dd>This parameter returns the number of dirty cache entries that have
7987** been written to disk in the middle of a transaction due to the page
7988** cache overflowing. Transactions are more efficient if they are written
7989** to disk all at once. When pages spill mid-transaction, that introduces
7990** additional overhead. This parameter can be used help identify
7991** inefficiencies that can be resolved by increasing the cache size.
7992** </dd>
7993**
7994** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
7995** <dd>This parameter returns zero for the current value if and only if
7996** all foreign key constraints (deferred or immediate) have been
7997** resolved.)^ ^The highwater mark is always 0.
7998** </dd>
7999** </dl>
8000*/
8001#define SQLITE_DBSTATUS_LOOKASIDE_USED 0
8002#define SQLITE_DBSTATUS_CACHE_USED 1
8003#define SQLITE_DBSTATUS_SCHEMA_USED 2
8004#define SQLITE_DBSTATUS_STMT_USED 3
8005#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
8006#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
8007#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
8008#define SQLITE_DBSTATUS_CACHE_HIT 7
8009#define SQLITE_DBSTATUS_CACHE_MISS 8
8010#define SQLITE_DBSTATUS_CACHE_WRITE 9
8011#define SQLITE_DBSTATUS_DEFERRED_FKS 10
8012#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11
8013#define SQLITE_DBSTATUS_CACHE_SPILL 12
8014#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */
8015
8016
8017/*
8018** CAPI3REF: Prepared Statement Status
8019** METHOD: sqlite3_stmt
8020**
8021** ^(Each prepared statement maintains various
8022** [SQLITE_STMTSTATUS counters] that measure the number
8023** of times it has performed specific operations.)^ These counters can
8024** be used to monitor the performance characteristics of the prepared
8025** statements. For example, if the number of table steps greatly exceeds
8026** the number of table searches or result rows, that would tend to indicate
8027** that the prepared statement is using a full table scan rather than
8028** an index.
8029**
8030** ^(This interface is used to retrieve and reset counter values from
8031** a [prepared statement]. The first argument is the prepared statement
8032** object to be interrogated. The second argument
8033** is an integer code for a specific [SQLITE_STMTSTATUS counter]
8034** to be interrogated.)^
8035** ^The current value of the requested counter is returned.
8036** ^If the resetFlg is true, then the counter is reset to zero after this
8037** interface call returns.
8038**
8039** See also: [sqlite3_status()] and [sqlite3_db_status()].
8040*/
8041
8042/*
8043** CAPI3REF: Status Parameters for prepared statements
8044** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
8045**
8046** These preprocessor macros define integer codes that name counter
8047** values associated with the [sqlite3_stmt_status()] interface.
8048** The meanings of the various counters are as follows:
8049**
8050** <dl>
8051** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
8052** <dd>^This is the number of times that SQLite has stepped forward in
8053** a table as part of a full table scan. Large numbers for this counter
8054** may indicate opportunities for performance improvement through
8055** careful use of indices.</dd>
8056**
8057** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
8058** <dd>^This is the number of sort operations that have occurred.
8059** A non-zero value in this counter may indicate an opportunity to
8060** improvement performance through careful use of indices.</dd>
8061**
8062** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
8063** <dd>^This is the number of rows inserted into transient indices that
8064** were created automatically in order to help joins run faster.
8065** A non-zero value in this counter may indicate an opportunity to
8066** improvement performance by adding permanent indices that do not
8067** need to be reinitialized each time the statement is run.</dd>
8068**
8069** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
8070** <dd>^This is the number of virtual machine operations executed
8071** by the prepared statement if that number is less than or equal
8072** to 2147483647. The number of virtual machine operations can be
8073** used as a proxy for the total work done by the prepared statement.
8074** If the number of virtual machine operations exceeds 2147483647
8075** then the value returned by this statement status code is undefined.
8076**
8077** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
8078** <dd>^This is the number of times that the prepare statement has been
8079** automatically regenerated due to schema changes or changes to
8080** [bound parameters] that might affect the query plan.
8081**
8082** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
8083** <dd>^This is the number of times that the prepared statement has
8084** been run. A single "run" for the purposes of this counter is one
8085** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
8086** The counter is incremented on the first [sqlite3_step()] call of each
8087** cycle.
8088**
8089** [[SQLITE_STMTSTATUS_FILTER_MISS]]
8090** [[SQLITE_STMTSTATUS_FILTER HIT]]
8091** <dt>SQLITE_STMTSTATUS_FILTER_HIT<br>
8092** SQLITE_STMTSTATUS_FILTER_MISS</dt>
8093** <dd>^SQLITE_STMTSTATUS_FILTER_HIT is the number of times that a join
8094** step was bypassed because a Bloom filter returned not-found. The
8095** corresponding SQLITE_STMTSTATUS_FILTER_MISS value is the number of
8096** times that the Bloom filter returned a find, and thus the join step
8097** had to be processed as normal.
8098**
8099** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
8100** <dd>^This is the approximate number of bytes of heap memory
8101** used to store the prepared statement. ^This value is not actually
8102** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
8103** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
8104** </dd>
8105** </dl>
8106*/
8107#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
8108#define SQLITE_STMTSTATUS_SORT 2
8109#define SQLITE_STMTSTATUS_AUTOINDEX 3
8110#define SQLITE_STMTSTATUS_VM_STEP 4
8111#define SQLITE_STMTSTATUS_REPREPARE 5
8112#define SQLITE_STMTSTATUS_RUN 6
8113#define SQLITE_STMTSTATUS_FILTER_MISS 7
8114#define SQLITE_STMTSTATUS_FILTER_HIT 8
8115#define SQLITE_STMTSTATUS_MEMUSED 99
8116
8117/*
8118** CAPI3REF: Custom Page Cache Object
8119**
8120** The sqlite3_pcache type is opaque. It is implemented by
8121** the pluggable module. The SQLite core has no knowledge of
8122** its size or internal structure and never deals with the
8123** sqlite3_pcache object except by holding and passing pointers
8124** to the object.
8125**
8126** See [sqlite3_pcache_methods2] for additional information.
8127*/
8128typedef struct sqlite3_pcache sqlite3_pcache;
8129
8130/*
8131** CAPI3REF: Custom Page Cache Object
8132**
8133** The sqlite3_pcache_page object represents a single page in the
8134** page cache. The page cache will allocate instances of this
8135** object. Various methods of the page cache use pointers to instances
8136** of this object as parameters or as their return value.
8137**
8138** See [sqlite3_pcache_methods2] for additional information.
8139*/
8140typedef struct sqlite3_pcache_page sqlite3_pcache_page;
8141struct sqlite3_pcache_page {
8142 void *pBuf; /* The content of the page */
8143 void *pExtra; /* Extra information associated with the page */
8144};
8145
8146/*
8147** CAPI3REF: Application Defined Page Cache.
8148** KEYWORDS: {page cache}
8149**
8150** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
8151** register an alternative page cache implementation by passing in an
8152** instance of the sqlite3_pcache_methods2 structure.)^
8153** In many applications, most of the heap memory allocated by
8154** SQLite is used for the page cache.
8155** By implementing a
8156** custom page cache using this API, an application can better control
8157** the amount of memory consumed by SQLite, the way in which
8158** that memory is allocated and released, and the policies used to
8159** determine exactly which parts of a database file are cached and for
8160** how long.
8161**
8162** The alternative page cache mechanism is an
8163** extreme measure that is only needed by the most demanding applications.
8164** The built-in page cache is recommended for most uses.
8165**
8166** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
8167** internal buffer by SQLite within the call to [sqlite3_config]. Hence
8168** the application may discard the parameter after the call to
8169** [sqlite3_config()] returns.)^
8170**
8171** [[the xInit() page cache method]]
8172** ^(The xInit() method is called once for each effective
8173** call to [sqlite3_initialize()])^
8174** (usually only once during the lifetime of the process). ^(The xInit()
8175** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
8176** The intent of the xInit() method is to set up global data structures
8177** required by the custom page cache implementation.
8178** ^(If the xInit() method is NULL, then the
8179** built-in default page cache is used instead of the application defined
8180** page cache.)^
8181**
8182** [[the xShutdown() page cache method]]
8183** ^The xShutdown() method is called by [sqlite3_shutdown()].
8184** It can be used to clean up
8185** any outstanding resources before process shutdown, if required.
8186** ^The xShutdown() method may be NULL.
8187**
8188** ^SQLite automatically serializes calls to the xInit method,
8189** so the xInit method need not be threadsafe. ^The
8190** xShutdown method is only called from [sqlite3_shutdown()] so it does
8191** not need to be threadsafe either. All other methods must be threadsafe
8192** in multithreaded applications.
8193**
8194** ^SQLite will never invoke xInit() more than once without an intervening
8195** call to xShutdown().
8196**
8197** [[the xCreate() page cache methods]]
8198** ^SQLite invokes the xCreate() method to construct a new cache instance.
8199** SQLite will typically create one cache instance for each open database file,
8200** though this is not guaranteed. ^The
8201** first parameter, szPage, is the size in bytes of the pages that must
8202** be allocated by the cache. ^szPage will always a power of two. ^The
8203** second parameter szExtra is a number of bytes of extra storage
8204** associated with each page cache entry. ^The szExtra parameter will
8205** a number less than 250. SQLite will use the
8206** extra szExtra bytes on each page to store metadata about the underlying
8207** database page on disk. The value passed into szExtra depends
8208** on the SQLite version, the target platform, and how SQLite was compiled.
8209** ^The third argument to xCreate(), bPurgeable, is true if the cache being
8210** created will be used to cache database pages of a file stored on disk, or
8211** false if it is used for an in-memory database. The cache implementation
8212** does not have to do anything special based with the value of bPurgeable;
8213** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
8214** never invoke xUnpin() except to deliberately delete a page.
8215** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
8216** false will always have the "discard" flag set to true.
8217** ^Hence, a cache created with bPurgeable false will
8218** never contain any unpinned pages.
8219**
8220** [[the xCachesize() page cache method]]
8221** ^(The xCachesize() method may be called at any time by SQLite to set the
8222** suggested maximum cache-size (number of pages stored by) the cache
8223** instance passed as the first argument. This is the value configured using
8224** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
8225** parameter, the implementation is not required to do anything with this
8226** value; it is advisory only.
8227**
8228** [[the xPagecount() page cache methods]]
8229** The xPagecount() method must return the number of pages currently
8230** stored in the cache, both pinned and unpinned.
8231**
8232** [[the xFetch() page cache methods]]
8233** The xFetch() method locates a page in the cache and returns a pointer to
8234** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
8235** The pBuf element of the returned sqlite3_pcache_page object will be a
8236** pointer to a buffer of szPage bytes used to store the content of a
8237** single database page. The pExtra element of sqlite3_pcache_page will be
8238** a pointer to the szExtra bytes of extra storage that SQLite has requested
8239** for each entry in the page cache.
8240**
8241** The page to be fetched is determined by the key. ^The minimum key value
8242** is 1. After it has been retrieved using xFetch, the page is considered
8243** to be "pinned".
8244**
8245** If the requested page is already in the page cache, then the page cache
8246** implementation must return a pointer to the page buffer with its content
8247** intact. If the requested page is not already in the cache, then the
8248** cache implementation should use the value of the createFlag
8249** parameter to help it determined what action to take:
8250**
8251** <table border=1 width=85% align=center>
8252** <tr><th> createFlag <th> Behavior when page is not already in cache
8253** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
8254** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
8255** Otherwise return NULL.
8256** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
8257** NULL if allocating a new page is effectively impossible.
8258** </table>
8259**
8260** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
8261** will only use a createFlag of 2 after a prior call with a createFlag of 1
8262** failed.)^ In between the xFetch() calls, SQLite may
8263** attempt to unpin one or more cache pages by spilling the content of
8264** pinned pages to disk and synching the operating system disk cache.
8265**
8266** [[the xUnpin() page cache method]]
8267** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
8268** as its second argument. If the third parameter, discard, is non-zero,
8269** then the page must be evicted from the cache.
8270** ^If the discard parameter is
8271** zero, then the page may be discarded or retained at the discretion of
8272** page cache implementation. ^The page cache implementation
8273** may choose to evict unpinned pages at any time.
8274**
8275** The cache must not perform any reference counting. A single
8276** call to xUnpin() unpins the page regardless of the number of prior calls
8277** to xFetch().
8278**
8279** [[the xRekey() page cache methods]]
8280** The xRekey() method is used to change the key value associated with the
8281** page passed as the second argument. If the cache
8282** previously contains an entry associated with newKey, it must be
8283** discarded. ^Any prior cache entry associated with newKey is guaranteed not
8284** to be pinned.
8285**
8286** When SQLite calls the xTruncate() method, the cache must discard all
8287** existing cache entries with page numbers (keys) greater than or equal
8288** to the value of the iLimit parameter passed to xTruncate(). If any
8289** of these pages are pinned, they are implicitly unpinned, meaning that
8290** they can be safely discarded.
8291**
8292** [[the xDestroy() page cache method]]
8293** ^The xDestroy() method is used to delete a cache allocated by xCreate().
8294** All resources associated with the specified cache should be freed. ^After
8295** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
8296** handle invalid, and will not use it with any other sqlite3_pcache_methods2
8297** functions.
8298**
8299** [[the xShrink() page cache method]]
8300** ^SQLite invokes the xShrink() method when it wants the page cache to
8301** free up as much of heap memory as possible. The page cache implementation
8302** is not obligated to free any memory, but well-behaved implementations should
8303** do their best.
8304*/
8305typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
8306struct sqlite3_pcache_methods2 {
8307 int iVersion;
8308 void *pArg;
8309 int (*xInit)(void*);
8310 void (*xShutdown)(void*);
8311 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
8312 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
8313 int (*xPagecount)(sqlite3_pcache*);
8314 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
8315 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
8316 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
8317 unsigned oldKey, unsigned newKey);
8318 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
8319 void (*xDestroy)(sqlite3_pcache*);
8320 void (*xShrink)(sqlite3_pcache*);
8321};
8322
8323/*
8324** This is the obsolete pcache_methods object that has now been replaced
8325** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
8326** retained in the header file for backwards compatibility only.
8327*/
8328typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
8329struct sqlite3_pcache_methods {
8330 void *pArg;
8331 int (*xInit)(void*);
8332 void (*xShutdown)(void*);
8333 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
8334 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
8335 int (*xPagecount)(sqlite3_pcache*);
8336 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
8337 void (*xUnpin)(sqlite3_pcache*, void*, int discard);
8338 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
8339 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
8340 void (*xDestroy)(sqlite3_pcache*);
8341};
8342
8343
8344/*
8345** CAPI3REF: Online Backup Object
8346**
8347** The sqlite3_backup object records state information about an ongoing
8348** online backup operation. ^The sqlite3_backup object is created by
8349** a call to [sqlite3_backup_init()] and is destroyed by a call to
8350** [sqlite3_backup_finish()].
8351**
8352** See Also: [Using the SQLite Online Backup API]
8353*/
8354typedef struct sqlite3_backup sqlite3_backup;
8355
8356/*
8357** CAPI3REF: Online Backup API.
8358**
8359** The backup API copies the content of one database into another.
8360** It is useful either for creating backups of databases or
8361** for copying in-memory databases to or from persistent files.
8362**
8363** See Also: [Using the SQLite Online Backup API]
8364**
8365** ^SQLite holds a write transaction open on the destination database file
8366** for the duration of the backup operation.
8367** ^The source database is read-locked only while it is being read;
8368** it is not locked continuously for the entire backup operation.
8369** ^Thus, the backup may be performed on a live source database without
8370** preventing other database connections from
8371** reading or writing to the source database while the backup is underway.
8372**
8373** ^(To perform a backup operation:
8374** <ol>
8375** <li><b>sqlite3_backup_init()</b> is called once to initialize the
8376** backup,
8377** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
8378** the data between the two databases, and finally
8379** <li><b>sqlite3_backup_finish()</b> is called to release all resources
8380** associated with the backup operation.
8381** </ol>)^
8382** There should be exactly one call to sqlite3_backup_finish() for each
8383** successful call to sqlite3_backup_init().
8384**
8385** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
8386**
8387** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
8388** [database connection] associated with the destination database
8389** and the database name, respectively.
8390** ^The database name is "main" for the main database, "temp" for the
8391** temporary database, or the name specified after the AS keyword in
8392** an [ATTACH] statement for an attached database.
8393** ^The S and M arguments passed to
8394** sqlite3_backup_init(D,N,S,M) identify the [database connection]
8395** and database name of the source database, respectively.
8396** ^The source and destination [database connections] (parameters S and D)
8397** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
8398** an error.
8399**
8400** ^A call to sqlite3_backup_init() will fail, returning NULL, if
8401** there is already a read or read-write transaction open on the
8402** destination database.
8403**
8404** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
8405** returned and an error code and error message are stored in the
8406** destination [database connection] D.
8407** ^The error code and message for the failed call to sqlite3_backup_init()
8408** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
8409** [sqlite3_errmsg16()] functions.
8410** ^A successful call to sqlite3_backup_init() returns a pointer to an
8411** [sqlite3_backup] object.
8412** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
8413** sqlite3_backup_finish() functions to perform the specified backup
8414** operation.
8415**
8416** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
8417**
8418** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
8419** the source and destination databases specified by [sqlite3_backup] object B.
8420** ^If N is negative, all remaining source pages are copied.
8421** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
8422** are still more pages to be copied, then the function returns [SQLITE_OK].
8423** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
8424** from source to destination, then it returns [SQLITE_DONE].
8425** ^If an error occurs while running sqlite3_backup_step(B,N),
8426** then an [error code] is returned. ^As well as [SQLITE_OK] and
8427** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
8428** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
8429** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
8430**
8431** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
8432** <ol>
8433** <li> the destination database was opened read-only, or
8434** <li> the destination database is using write-ahead-log journaling
8435** and the destination and source page sizes differ, or
8436** <li> the destination database is an in-memory database and the
8437** destination and source page sizes differ.
8438** </ol>)^
8439**
8440** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
8441** the [sqlite3_busy_handler | busy-handler function]
8442** is invoked (if one is specified). ^If the
8443** busy-handler returns non-zero before the lock is available, then
8444** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
8445** sqlite3_backup_step() can be retried later. ^If the source
8446** [database connection]
8447** is being used to write to the source database when sqlite3_backup_step()
8448** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
8449** case the call to sqlite3_backup_step() can be retried later on. ^(If
8450** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
8451** [SQLITE_READONLY] is returned, then
8452** there is no point in retrying the call to sqlite3_backup_step(). These
8453** errors are considered fatal.)^ The application must accept
8454** that the backup operation has failed and pass the backup operation handle
8455** to the sqlite3_backup_finish() to release associated resources.
8456**
8457** ^The first call to sqlite3_backup_step() obtains an exclusive lock
8458** on the destination file. ^The exclusive lock is not released until either
8459** sqlite3_backup_finish() is called or the backup operation is complete
8460** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
8461** sqlite3_backup_step() obtains a [shared lock] on the source database that
8462** lasts for the duration of the sqlite3_backup_step() call.
8463** ^Because the source database is not locked between calls to
8464** sqlite3_backup_step(), the source database may be modified mid-way
8465** through the backup process. ^If the source database is modified by an
8466** external process or via a database connection other than the one being
8467** used by the backup operation, then the backup will be automatically
8468** restarted by the next call to sqlite3_backup_step(). ^If the source
8469** database is modified by the using the same database connection as is used
8470** by the backup operation, then the backup database is automatically
8471** updated at the same time.
8472**
8473** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
8474**
8475** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
8476** application wishes to abandon the backup operation, the application
8477** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
8478** ^The sqlite3_backup_finish() interfaces releases all
8479** resources associated with the [sqlite3_backup] object.
8480** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
8481** active write-transaction on the destination database is rolled back.
8482** The [sqlite3_backup] object is invalid
8483** and may not be used following a call to sqlite3_backup_finish().
8484**
8485** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
8486** sqlite3_backup_step() errors occurred, regardless or whether or not
8487** sqlite3_backup_step() completed.
8488** ^If an out-of-memory condition or IO error occurred during any prior
8489** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
8490** sqlite3_backup_finish() returns the corresponding [error code].
8491**
8492** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
8493** is not a permanent error and does not affect the return value of
8494** sqlite3_backup_finish().
8495**
8496** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
8497** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
8498**
8499** ^The sqlite3_backup_remaining() routine returns the number of pages still
8500** to be backed up at the conclusion of the most recent sqlite3_backup_step().
8501** ^The sqlite3_backup_pagecount() routine returns the total number of pages
8502** in the source database at the conclusion of the most recent
8503** sqlite3_backup_step().
8504** ^(The values returned by these functions are only updated by
8505** sqlite3_backup_step(). If the source database is modified in a way that
8506** changes the size of the source database or the number of pages remaining,
8507** those changes are not reflected in the output of sqlite3_backup_pagecount()
8508** and sqlite3_backup_remaining() until after the next
8509** sqlite3_backup_step().)^
8510**
8511** <b>Concurrent Usage of Database Handles</b>
8512**
8513** ^The source [database connection] may be used by the application for other
8514** purposes while a backup operation is underway or being initialized.
8515** ^If SQLite is compiled and configured to support threadsafe database
8516** connections, then the source database connection may be used concurrently
8517** from within other threads.
8518**
8519** However, the application must guarantee that the destination
8520** [database connection] is not passed to any other API (by any thread) after
8521** sqlite3_backup_init() is called and before the corresponding call to
8522** sqlite3_backup_finish(). SQLite does not currently check to see
8523** if the application incorrectly accesses the destination [database connection]
8524** and so no error code is reported, but the operations may malfunction
8525** nevertheless. Use of the destination database connection while a
8526** backup is in progress might also also cause a mutex deadlock.
8527**
8528** If running in [shared cache mode], the application must
8529** guarantee that the shared cache used by the destination database
8530** is not accessed while the backup is running. In practice this means
8531** that the application must guarantee that the disk file being
8532** backed up to is not accessed by any connection within the process,
8533** not just the specific connection that was passed to sqlite3_backup_init().
8534**
8535** The [sqlite3_backup] object itself is partially threadsafe. Multiple
8536** threads may safely make multiple concurrent calls to sqlite3_backup_step().
8537** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
8538** APIs are not strictly speaking threadsafe. If they are invoked at the
8539** same time as another thread is invoking sqlite3_backup_step() it is
8540** possible that they return invalid values.
8541*/
8542
8543/*
8544** CAPI3REF: Unlock Notification
8545** METHOD: sqlite3
8546**
8547** ^When running in shared-cache mode, a database operation may fail with
8548** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
8549** individual tables within the shared-cache cannot be obtained. See
8550** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
8551** ^This API may be used to register a callback that SQLite will invoke
8552** when the connection currently holding the required lock relinquishes it.
8553** ^This API is only available if the library was compiled with the
8554** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
8555**
8556** See Also: [Using the SQLite Unlock Notification Feature].
8557**
8558** ^Shared-cache locks are released when a database connection concludes
8559** its current transaction, either by committing it or rolling it back.
8560**
8561** ^When a connection (known as the blocked connection) fails to obtain a
8562** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
8563** identity of the database connection (the blocking connection) that
8564** has locked the required resource is stored internally. ^After an
8565** application receives an SQLITE_LOCKED error, it may call the
8566** sqlite3_unlock_notify() method with the blocked connection handle as
8567** the first argument to register for a callback that will be invoked
8568** when the blocking connections current transaction is concluded. ^The
8569** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
8570** call that concludes the blocking connection's transaction.
8571**
8572** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
8573** there is a chance that the blocking connection will have already
8574** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
8575** If this happens, then the specified callback is invoked immediately,
8576** from within the call to sqlite3_unlock_notify().)^
8577**
8578** ^If the blocked connection is attempting to obtain a write-lock on a
8579** shared-cache table, and more than one other connection currently holds
8580** a read-lock on the same table, then SQLite arbitrarily selects one of
8581** the other connections to use as the blocking connection.
8582**
8583** ^(There may be at most one unlock-notify callback registered by a
8584** blocked connection. If sqlite3_unlock_notify() is called when the
8585** blocked connection already has a registered unlock-notify callback,
8586** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
8587** called with a NULL pointer as its second argument, then any existing
8588** unlock-notify callback is canceled. ^The blocked connections
8589** unlock-notify callback may also be canceled by closing the blocked
8590** connection using [sqlite3_close()].
8591**
8592** The unlock-notify callback is not reentrant. If an application invokes
8593** any sqlite3_xxx API functions from within an unlock-notify callback, a
8594** crash or deadlock may be the result.
8595**
8596** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
8597** returns SQLITE_OK.
8598**
8599** <b>Callback Invocation Details</b>
8600**
8601** When an unlock-notify callback is registered, the application provides a
8602** single void* pointer that is passed to the callback when it is invoked.
8603** However, the signature of the callback function allows SQLite to pass
8604** it an array of void* context pointers. The first argument passed to
8605** an unlock-notify callback is a pointer to an array of void* pointers,
8606** and the second is the number of entries in the array.
8607**
8608** When a blocking connection's transaction is concluded, there may be
8609** more than one blocked connection that has registered for an unlock-notify
8610** callback. ^If two or more such blocked connections have specified the
8611** same callback function, then instead of invoking the callback function
8612** multiple times, it is invoked once with the set of void* context pointers
8613** specified by the blocked connections bundled together into an array.
8614** This gives the application an opportunity to prioritize any actions
8615** related to the set of unblocked database connections.
8616**
8617** <b>Deadlock Detection</b>
8618**
8619** Assuming that after registering for an unlock-notify callback a
8620** database waits for the callback to be issued before taking any further
8621** action (a reasonable assumption), then using this API may cause the
8622** application to deadlock. For example, if connection X is waiting for
8623** connection Y's transaction to be concluded, and similarly connection
8624** Y is waiting on connection X's transaction, then neither connection
8625** will proceed and the system may remain deadlocked indefinitely.
8626**
8627** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
8628** detection. ^If a given call to sqlite3_unlock_notify() would put the
8629** system in a deadlocked state, then SQLITE_LOCKED is returned and no
8630** unlock-notify callback is registered. The system is said to be in
8631** a deadlocked state if connection A has registered for an unlock-notify
8632** callback on the conclusion of connection B's transaction, and connection
8633** B has itself registered for an unlock-notify callback when connection
8634** A's transaction is concluded. ^Indirect deadlock is also detected, so
8635** the system is also considered to be deadlocked if connection B has
8636** registered for an unlock-notify callback on the conclusion of connection
8637** C's transaction, where connection C is waiting on connection A. ^Any
8638** number of levels of indirection are allowed.
8639**
8640** <b>The "DROP TABLE" Exception</b>
8641**
8642** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
8643** always appropriate to call sqlite3_unlock_notify(). There is however,
8644** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
8645** SQLite checks if there are any currently executing SELECT statements
8646** that belong to the same connection. If there are, SQLITE_LOCKED is
8647** returned. In this case there is no "blocking connection", so invoking
8648** sqlite3_unlock_notify() results in the unlock-notify callback being
8649** invoked immediately. If the application then re-attempts the "DROP TABLE"
8650** or "DROP INDEX" query, an infinite loop might be the result.
8651**
8652** One way around this problem is to check the extended error code returned
8653** by an sqlite3_step() call. ^(If there is a blocking connection, then the
8654** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
8655** the special "DROP TABLE/INDEX" case, the extended error code is just
8656** SQLITE_LOCKED.)^
8657*/
8658
8659
8660/*
8661** CAPI3REF: String Comparison
8662**
8663** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
8664** and extensions to compare the contents of two buffers containing UTF-8
8665** strings in a case-independent fashion, using the same definition of "case
8666** independence" that SQLite uses internally when comparing identifiers.
8667*/
8668
8669/*
8670** CAPI3REF: String Globbing
8671*
8672** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
8673** string X matches the [GLOB] pattern P.
8674** ^The definition of [GLOB] pattern matching used in
8675** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
8676** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function
8677** is case sensitive.
8678**
8679** Note that this routine returns zero on a match and non-zero if the strings
8680** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
8681**
8682** See also: [sqlite3_strlike()].
8683*/
8684
8685/*
8686** CAPI3REF: String LIKE Matching
8687*
8688** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
8689** string X matches the [LIKE] pattern P with escape character E.
8690** ^The definition of [LIKE] pattern matching used in
8691** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
8692** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without
8693** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
8694** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
8695** insensitive - equivalent upper and lower case ASCII characters match
8696** one another.
8697**
8698** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
8699** only ASCII characters are case folded.
8700**
8701** Note that this routine returns zero on a match and non-zero if the strings
8702** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
8703**
8704** See also: [sqlite3_strglob()].
8705*/
8706
8707/*
8708** CAPI3REF: Error Logging Interface
8709**
8710** ^The [sqlite3_log()] interface writes a message into the [error log]
8711** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
8712** ^If logging is enabled, the zFormat string and subsequent arguments are
8713** used with [sqlite3_snprintf()] to generate the final output string.
8714**
8715** The sqlite3_log() interface is intended for use by extensions such as
8716** virtual tables, collating functions, and SQL functions. While there is
8717** nothing to prevent an application from calling sqlite3_log(), doing so
8718** is considered bad form.
8719**
8720** The zFormat string must not be NULL.
8721**
8722** To avoid deadlocks and other threading problems, the sqlite3_log() routine
8723** will not use dynamically allocated memory. The log message is stored in
8724** a fixed-length buffer on the stack. If the log message is longer than
8725** a few hundred characters, it will be truncated to the length of the
8726** buffer.
8727*/
8728
8729/*
8730** CAPI3REF: Write-Ahead Log Commit Hook
8731** METHOD: sqlite3
8732**
8733** ^The [sqlite3_wal_hook()] function is used to register a callback that
8734** is invoked each time data is committed to a database in wal mode.
8735**
8736** ^(The callback is invoked by SQLite after the commit has taken place and
8737** the associated write-lock on the database released)^, so the implementation
8738** may read, write or [checkpoint] the database as required.
8739**
8740** ^The first parameter passed to the callback function when it is invoked
8741** is a copy of the third parameter passed to sqlite3_wal_hook() when
8742** registering the callback. ^The second is a copy of the database handle.
8743** ^The third parameter is the name of the database that was written to -
8744** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
8745** is the number of pages currently in the write-ahead log file,
8746** including those that were just committed.
8747**
8748** The callback function should normally return [SQLITE_OK]. ^If an error
8749** code is returned, that error will propagate back up through the
8750** SQLite code base to cause the statement that provoked the callback
8751** to report an error, though the commit will have still occurred. If the
8752** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
8753** that does not correspond to any valid SQLite error code, the results
8754** are undefined.
8755**
8756** A single database handle may have at most a single write-ahead log callback
8757** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
8758** previously registered write-ahead log callback. ^The return value is
8759** a copy of the third parameter from the previous call, if any, or 0.
8760** ^Note that the [sqlite3_wal_autocheckpoint()] interface and the
8761** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
8762** overwrite any prior [sqlite3_wal_hook()] settings.
8763*/
8764
8765/*
8766** CAPI3REF: Configure an auto-checkpoint
8767** METHOD: sqlite3
8768**
8769** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
8770** [sqlite3_wal_hook()] that causes any database on [database connection] D
8771** to automatically [checkpoint]
8772** after committing a transaction if there are N or
8773** more frames in the [write-ahead log] file. ^Passing zero or
8774** a negative value as the nFrame parameter disables automatic
8775** checkpoints entirely.
8776**
8777** ^The callback registered by this function replaces any existing callback
8778** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
8779** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
8780** configured by this function.
8781**
8782** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
8783** from SQL.
8784**
8785** ^Checkpoints initiated by this mechanism are
8786** [sqlite3_wal_checkpoint_v2|PASSIVE].
8787**
8788** ^Every new [database connection] defaults to having the auto-checkpoint
8789** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
8790** pages. The use of this interface
8791** is only necessary if the default setting is found to be suboptimal
8792** for a particular application.
8793*/
8794
8795/*
8796** CAPI3REF: Checkpoint a database
8797** METHOD: sqlite3
8798**
8799** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
8800** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
8801**
8802** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
8803** [write-ahead log] for database X on [database connection] D to be
8804** transferred into the database file and for the write-ahead log to
8805** be reset. See the [checkpointing] documentation for addition
8806** information.
8807**
8808** This interface used to be the only way to cause a checkpoint to
8809** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
8810** interface was added. This interface is retained for backwards
8811** compatibility and as a convenience for applications that need to manually
8812** start a callback but which do not need the full power (and corresponding
8813** complication) of [sqlite3_wal_checkpoint_v2()].
8814*/
8815
8816/*
8817** CAPI3REF: Checkpoint a database
8818** METHOD: sqlite3
8819**
8820** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
8821** operation on database X of [database connection] D in mode M. Status
8822** information is written back into integers pointed to by L and C.)^
8823** ^(The M parameter must be a valid [checkpoint mode]:)^
8824**
8825** <dl>
8826** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
8827** ^Checkpoint as many frames as possible without waiting for any database
8828** readers or writers to finish, then sync the database file if all frames
8829** in the log were checkpointed. ^The [busy-handler callback]
8830** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
8831** ^On the other hand, passive mode might leave the checkpoint unfinished
8832** if there are concurrent readers or writers.
8833**
8834** <dt>SQLITE_CHECKPOINT_FULL<dd>
8835** ^This mode blocks (it invokes the
8836** [sqlite3_busy_handler|busy-handler callback]) until there is no
8837** database writer and all readers are reading from the most recent database
8838** snapshot. ^It then checkpoints all frames in the log file and syncs the
8839** database file. ^This mode blocks new database writers while it is pending,
8840** but new database readers are allowed to continue unimpeded.
8841**
8842** <dt>SQLITE_CHECKPOINT_RESTART<dd>
8843** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
8844** that after checkpointing the log file it blocks (calls the
8845** [busy-handler callback])
8846** until all readers are reading from the database file only. ^This ensures
8847** that the next writer will restart the log file from the beginning.
8848** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
8849** database writer attempts while it is pending, but does not impede readers.
8850**
8851** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
8852** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
8853** addition that it also truncates the log file to zero bytes just prior
8854** to a successful return.
8855** </dl>
8856**
8857** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
8858** the log file or to -1 if the checkpoint could not run because
8859** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
8860** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
8861** log file (including any that were already checkpointed before the function
8862** was called) or to -1 if the checkpoint could not run due to an error or
8863** because the database is not in WAL mode. ^Note that upon successful
8864** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
8865** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
8866**
8867** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
8868** any other process is running a checkpoint operation at the same time, the
8869** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
8870** busy-handler configured, it will not be invoked in this case.
8871**
8872** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
8873** exclusive "writer" lock on the database file. ^If the writer lock cannot be
8874** obtained immediately, and a busy-handler is configured, it is invoked and
8875** the writer lock retried until either the busy-handler returns 0 or the lock
8876** is successfully obtained. ^The busy-handler is also invoked while waiting for
8877** database readers as described above. ^If the busy-handler returns 0 before
8878** the writer lock is obtained or while waiting for database readers, the
8879** checkpoint operation proceeds from that point in the same way as
8880** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
8881** without blocking any further. ^SQLITE_BUSY is returned in this case.
8882**
8883** ^If parameter zDb is NULL or points to a zero length string, then the
8884** specified operation is attempted on all WAL databases [attached] to
8885** [database connection] db. In this case the
8886** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
8887** an SQLITE_BUSY error is encountered when processing one or more of the
8888** attached WAL databases, the operation is still attempted on any remaining
8889** attached databases and SQLITE_BUSY is returned at the end. ^If any other
8890** error occurs while processing an attached database, processing is abandoned
8891** and the error code is returned to the caller immediately. ^If no error
8892** (SQLITE_BUSY or otherwise) is encountered while processing the attached
8893** databases, SQLITE_OK is returned.
8894**
8895** ^If database zDb is the name of an attached database that is not in WAL
8896** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
8897** zDb is not NULL (or a zero length string) and is not the name of any
8898** attached database, SQLITE_ERROR is returned to the caller.
8899**
8900** ^Unless it returns SQLITE_MISUSE,
8901** the sqlite3_wal_checkpoint_v2() interface
8902** sets the error information that is queried by
8903** [sqlite3_errcode()] and [sqlite3_errmsg()].
8904**
8905** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
8906** from SQL.
8907*/
8908
8909/*
8910** CAPI3REF: Checkpoint Mode Values
8911** KEYWORDS: {checkpoint mode}
8912**
8913** These constants define all valid values for the "checkpoint mode" passed
8914** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
8915** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
8916** meaning of each of these checkpoint modes.
8917*/
8918#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */
8919#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */
8920#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */
8921#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */
8922
8923/*
8924** CAPI3REF: Virtual Table Interface Configuration
8925**
8926** This function may be called by either the [xConnect] or [xCreate] method
8927** of a [virtual table] implementation to configure
8928** various facets of the virtual table interface.
8929**
8930** If this interface is invoked outside the context of an xConnect or
8931** xCreate virtual table method then the behavior is undefined.
8932**
8933** In the call sqlite3_vtab_config(D,C,...) the D parameter is the
8934** [database connection] in which the virtual table is being created and
8935** which is passed in as the first argument to the [xConnect] or [xCreate]
8936** method that is invoking sqlite3_vtab_config(). The C parameter is one
8937** of the [virtual table configuration options]. The presence and meaning
8938** of parameters after C depend on which [virtual table configuration option]
8939** is used.
8940*/
8941
8942/*
8943** CAPI3REF: Virtual Table Configuration Options
8944** KEYWORDS: {virtual table configuration options}
8945** KEYWORDS: {virtual table configuration option}
8946**
8947** These macros define the various options to the
8948** [sqlite3_vtab_config()] interface that [virtual table] implementations
8949** can use to customize and optimize their behavior.
8950**
8951** <dl>
8952** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]]
8953** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt>
8954** <dd>Calls of the form
8955** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
8956** where X is an integer. If X is zero, then the [virtual table] whose
8957** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
8958** support constraints. In this configuration (which is the default) if
8959** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
8960** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
8961** specified as part of the users SQL statement, regardless of the actual
8962** ON CONFLICT mode specified.
8963**
8964** If X is non-zero, then the virtual table implementation guarantees
8965** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
8966** any modifications to internal or persistent data structures have been made.
8967** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
8968** is able to roll back a statement or database transaction, and abandon
8969** or continue processing the current SQL statement as appropriate.
8970** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
8971** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
8972** had been ABORT.
8973**
8974** Virtual table implementations that are required to handle OR REPLACE
8975** must do so within the [xUpdate] method. If a call to the
8976** [sqlite3_vtab_on_conflict()] function indicates that the current ON
8977** CONFLICT policy is REPLACE, the virtual table implementation should
8978** silently replace the appropriate rows within the xUpdate callback and
8979** return SQLITE_OK. Or, if this is not possible, it may return
8980** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
8981** constraint handling.
8982** </dd>
8983**
8984** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt>
8985** <dd>Calls of the form
8986** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the
8987** the [xConnect] or [xCreate] methods of a [virtual table] implmentation
8988** prohibits that virtual table from being used from within triggers and
8989** views.
8990** </dd>
8991**
8992** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt>
8993** <dd>Calls of the form
8994** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the
8995** the [xConnect] or [xCreate] methods of a [virtual table] implmentation
8996** identify that virtual table as being safe to use from within triggers
8997** and views. Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the
8998** virtual table can do no serious harm even if it is controlled by a
8999** malicious hacker. Developers should avoid setting the SQLITE_VTAB_INNOCUOUS
9000** flag unless absolutely necessary.
9001** </dd>
9002** </dl>
9003*/
9004#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
9005#define SQLITE_VTAB_INNOCUOUS 2
9006#define SQLITE_VTAB_DIRECTONLY 3
9007
9008/*
9009** CAPI3REF: Determine The Virtual Table Conflict Policy
9010**
9011** This function may only be called from within a call to the [xUpdate] method
9012** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
9013** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
9014** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
9015** of the SQL statement that triggered the call to the [xUpdate] method of the
9016** [virtual table].
9017*/
9018
9019/*
9020** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
9021**
9022** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
9023** method of a [virtual table], then it might return true if the
9024** column is being fetched as part of an UPDATE operation during which the
9025** column value will not change. The virtual table implementation can use
9026** this hint as permission to substitute a return value that is less
9027** expensive to compute and that the corresponding
9028** [xUpdate] method understands as a "no-change" value.
9029**
9030** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
9031** the column is not changed by the UPDATE statement, then the xColumn
9032** method can optionally return without setting a result, without calling
9033** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
9034** In that case, [sqlite3_value_nochange(X)] will return true for the
9035** same column in the [xUpdate] method.
9036**
9037** The sqlite3_vtab_nochange() routine is an optimization. Virtual table
9038** implementations should continue to give a correct answer even if the
9039** sqlite3_vtab_nochange() interface were to always return false. In the
9040** current implementation, the sqlite3_vtab_nochange() interface does always
9041** returns false for the enhanced [UPDATE FROM] statement.
9042*/
9043
9044/*
9045** CAPI3REF: Determine The Collation For a Virtual Table Constraint
9046** METHOD: sqlite3_index_info
9047**
9048** This function may only be called from within a call to the [xBestIndex]
9049** method of a [virtual table]. This function returns a pointer to a string
9050** that is the name of the appropriate collation sequence to use for text
9051** comparisons on the constraint identified by its arguments.
9052**
9053** The first argument must be the pointer to the [sqlite3_index_info] object
9054** that is the first parameter to the xBestIndex() method. The second argument
9055** must be an index into the aConstraint[] array belonging to the
9056** sqlite3_index_info structure passed to xBestIndex.
9057**
9058** Important:
9059** The first parameter must be the same pointer that is passed into the
9060** xBestMethod() method. The first parameter may not be a pointer to a
9061** different [sqlite3_index_info] object, even an exact copy.
9062**
9063** The return value is computed as follows:
9064**
9065** <ol>
9066** <li><p> If the constraint comes from a WHERE clause expression that contains
9067** a [COLLATE operator], then the name of the collation specified by
9068** that COLLATE operator is returned.
9069** <li><p> If there is no COLLATE operator, but the column that is the subject
9070** of the constraint specifies an alternative collating sequence via
9071** a [COLLATE clause] on the column definition within the CREATE TABLE
9072** statement that was passed into [sqlite3_declare_vtab()], then the
9073** name of that alternative collating sequence is returned.
9074** <li><p> Otherwise, "BINARY" is returned.
9075** </ol>
9076*/
9077
9078/*
9079** CAPI3REF: Determine if a virtual table query is DISTINCT
9080** METHOD: sqlite3_index_info
9081**
9082** This API may only be used from within an [xBestIndex|xBestIndex method]
9083** of a [virtual table] implementation. The result of calling this
9084** interface from outside of xBestIndex() is undefined and probably harmful.
9085**
9086** ^The sqlite3_vtab_distinct() interface returns an integer between 0 and
9087** 3. The integer returned by sqlite3_vtab_distinct()
9088** gives the virtual table additional information about how the query
9089** planner wants the output to be ordered. As long as the virtual table
9090** can meet the ordering requirements of the query planner, it may set
9091** the "orderByConsumed" flag.
9092**
9093** <ol><li value="0"><p>
9094** ^If the sqlite3_vtab_distinct() interface returns 0, that means
9095** that the query planner needs the virtual table to return all rows in the
9096** sort order defined by the "nOrderBy" and "aOrderBy" fields of the
9097** [sqlite3_index_info] object. This is the default expectation. If the
9098** virtual table outputs all rows in sorted order, then it is always safe for
9099** the xBestIndex method to set the "orderByConsumed" flag, regardless of
9100** the return value from sqlite3_vtab_distinct().
9101** <li value="1"><p>
9102** ^(If the sqlite3_vtab_distinct() interface returns 1, that means
9103** that the query planner does not need the rows to be returned in sorted order
9104** as long as all rows with the same values in all columns identified by the
9105** "aOrderBy" field are adjacent.)^ This mode is used when the query planner
9106** is doing a GROUP BY.
9107** <li value="2"><p>
9108** ^(If the sqlite3_vtab_distinct() interface returns 2, that means
9109** that the query planner does not need the rows returned in any particular
9110** order, as long as rows with the same values in all "aOrderBy" columns
9111** are adjacent.)^ ^(Furthermore, only a single row for each particular
9112** combination of values in the columns identified by the "aOrderBy" field
9113** needs to be returned.)^ ^It is always ok for two or more rows with the same
9114** values in all "aOrderBy" columns to be returned, as long as all such rows
9115** are adjacent. ^The virtual table may, if it chooses, omit extra rows
9116** that have the same value for all columns identified by "aOrderBy".
9117** ^However omitting the extra rows is optional.
9118** This mode is used for a DISTINCT query.
9119** <li value="3"><p>
9120** ^(If the sqlite3_vtab_distinct() interface returns 3, that means
9121** that the query planner needs only distinct rows but it does need the
9122** rows to be sorted.)^ ^The virtual table implementation is free to omit
9123** rows that are identical in all aOrderBy columns, if it wants to, but
9124** it is not required to omit any rows. This mode is used for queries
9125** that have both DISTINCT and ORDER BY clauses.
9126** </ol>
9127**
9128** ^For the purposes of comparing virtual table output values to see if the
9129** values are same value for sorting purposes, two NULL values are considered
9130** to be the same. In other words, the comparison operator is "IS"
9131** (or "IS NOT DISTINCT FROM") and not "==".
9132**
9133** If a virtual table implementation is unable to meet the requirements
9134** specified above, then it must not set the "orderByConsumed" flag in the
9135** [sqlite3_index_info] object or an incorrect answer may result.
9136**
9137** ^A virtual table implementation is always free to return rows in any order
9138** it wants, as long as the "orderByConsumed" flag is not set. ^When the
9139** the "orderByConsumed" flag is unset, the query planner will add extra
9140** [bytecode] to ensure that the final results returned by the SQL query are
9141** ordered correctly. The use of the "orderByConsumed" flag and the
9142** sqlite3_vtab_distinct() interface is merely an optimization. ^Careful
9143** use of the sqlite3_vtab_distinct() interface and the "orderByConsumed"
9144** flag might help queries against a virtual table to run faster. Being
9145** overly aggressive and setting the "orderByConsumed" flag when it is not
9146** valid to do so, on the other hand, might cause SQLite to return incorrect
9147** results.
9148*/
9149
9150/*
9151** CAPI3REF: Identify and handle IN constraints in xBestIndex
9152**
9153** This interface may only be used from within an
9154** [xBestIndex|xBestIndex() method] of a [virtual table] implementation.
9155** The result of invoking this interface from any other context is
9156** undefined and probably harmful.
9157**
9158** ^(A constraint on a virtual table of the form
9159** "[IN operator|column IN (...)]" is
9160** communicated to the xBestIndex method as a
9161** [SQLITE_INDEX_CONSTRAINT_EQ] constraint.)^ If xBestIndex wants to use
9162** this constraint, it must set the corresponding
9163** aConstraintUsage[].argvIndex to a postive integer. ^(Then, under
9164** the usual mode of handling IN operators, SQLite generates [bytecode]
9165** that invokes the [xFilter|xFilter() method] once for each value
9166** on the right-hand side of the IN operator.)^ Thus the virtual table
9167** only sees a single value from the right-hand side of the IN operator
9168** at a time.
9169**
9170** In some cases, however, it would be advantageous for the virtual
9171** table to see all values on the right-hand of the IN operator all at
9172** once. The sqlite3_vtab_in() interfaces facilitates this in two ways:
9173**
9174** <ol>
9175** <li><p>
9176** ^A call to sqlite3_vtab_in(P,N,-1) will return true (non-zero)
9177** if and only if the [sqlite3_index_info|P->aConstraint][N] constraint
9178** is an [IN operator] that can be processed all at once. ^In other words,
9179** sqlite3_vtab_in() with -1 in the third argument is a mechanism
9180** by which the virtual table can ask SQLite if all-at-once processing
9181** of the IN operator is even possible.
9182**
9183** <li><p>
9184** ^A call to sqlite3_vtab_in(P,N,F) with F==1 or F==0 indicates
9185** to SQLite that the virtual table does or does not want to process
9186** the IN operator all-at-once, respectively. ^Thus when the third
9187** parameter (F) is non-negative, this interface is the mechanism by
9188** which the virtual table tells SQLite how it wants to process the
9189** IN operator.
9190** </ol>
9191**
9192** ^The sqlite3_vtab_in(P,N,F) interface can be invoked multiple times
9193** within the same xBestIndex method call. ^For any given P,N pair,
9194** the return value from sqlite3_vtab_in(P,N,F) will always be the same
9195** within the same xBestIndex call. ^If the interface returns true
9196** (non-zero), that means that the constraint is an IN operator
9197** that can be processed all-at-once. ^If the constraint is not an IN
9198** operator or cannot be processed all-at-once, then the interface returns
9199** false.
9200**
9201** ^(All-at-once processing of the IN operator is selected if both of the
9202** following conditions are met:
9203**
9204** <ol>
9205** <li><p> The P->aConstraintUsage[N].argvIndex value is set to a positive
9206** integer. This is how the virtual table tells SQLite that it wants to
9207** use the N-th constraint.
9208**
9209** <li><p> The last call to sqlite3_vtab_in(P,N,F) for which F was
9210** non-negative had F>=1.
9211** </ol>)^
9212**
9213** ^If either or both of the conditions above are false, then SQLite uses
9214** the traditional one-at-a-time processing strategy for the IN constraint.
9215** ^If both conditions are true, then the argvIndex-th parameter to the
9216** xFilter method will be an [sqlite3_value] that appears to be NULL,
9217** but which can be passed to [sqlite3_vtab_in_first()] and
9218** [sqlite3_vtab_in_next()] to find all values on the right-hand side
9219** of the IN constraint.
9220*/
9221
9222/*
9223** CAPI3REF: Find all elements on the right-hand side of an IN constraint.
9224**
9225** These interfaces are only useful from within the
9226** [xFilter|xFilter() method] of a [virtual table] implementation.
9227** The result of invoking these interfaces from any other context
9228** is undefined and probably harmful.
9229**
9230** The X parameter in a call to sqlite3_vtab_in_first(X,P) or
9231** sqlite3_vtab_in_next(X,P) must be one of the parameters to the
9232** xFilter method which invokes these routines, and specifically
9233** a parameter that was previously selected for all-at-once IN constraint
9234** processing use the [sqlite3_vtab_in()] interface in the
9235** [xBestIndex|xBestIndex method]. ^(If the X parameter is not
9236** an xFilter argument that was selected for all-at-once IN constraint
9237** processing, then these routines return [SQLITE_MISUSE])^ or perhaps
9238** exhibit some other undefined or harmful behavior.
9239**
9240** ^(Use these routines to access all values on the right-hand side
9241** of the IN constraint using code like the following:
9242**
9243** <blockquote><pre>
9244** &nbsp; for(rc=sqlite3_vtab_in_first(pList, &pVal);
9245** &nbsp; rc==SQLITE_OK && pVal
9246** &nbsp; rc=sqlite3_vtab_in_next(pList, &pVal)
9247** &nbsp; ){
9248** &nbsp; // do something with pVal
9249** &nbsp; }
9250** &nbsp; if( rc!=SQLITE_OK ){
9251** &nbsp; // an error has occurred
9252** &nbsp; }
9253** </pre></blockquote>)^
9254**
9255** ^On success, the sqlite3_vtab_in_first(X,P) and sqlite3_vtab_in_next(X,P)
9256** routines return SQLITE_OK and set *P to point to the first or next value
9257** on the RHS of the IN constraint. ^If there are no more values on the
9258** right hand side of the IN constraint, then *P is set to NULL and these
9259** routines return [SQLITE_DONE]. ^The return value might be
9260** some other value, such as SQLITE_NOMEM, in the event of a malfunction.
9261**
9262** The *ppOut values returned by these routines are only valid until the
9263** next call to either of these routines or until the end of the xFilter
9264** method from which these routines were called. If the virtual table
9265** implementation needs to retain the *ppOut values for longer, it must make
9266** copies. The *ppOut values are [protected sqlite3_value|protected].
9267*/
9268
9269/*
9270** CAPI3REF: Constraint values in xBestIndex()
9271** METHOD: sqlite3_index_info
9272**
9273** This API may only be used from within the [xBestIndex|xBestIndex method]
9274** of a [virtual table] implementation. The result of calling this interface
9275** from outside of an xBestIndex method are undefined and probably harmful.
9276**
9277** ^When the sqlite3_vtab_rhs_value(P,J,V) interface is invoked from within
9278** the [xBestIndex] method of a [virtual table] implementation, with P being
9279** a copy of the [sqlite3_index_info] object pointer passed into xBestIndex and
9280** J being a 0-based index into P->aConstraint[], then this routine
9281** attempts to set *V to the value of the right-hand operand of
9282** that constraint if the right-hand operand is known. ^If the
9283** right-hand operand is not known, then *V is set to a NULL pointer.
9284** ^The sqlite3_vtab_rhs_value(P,J,V) interface returns SQLITE_OK if
9285** and only if *V is set to a value. ^The sqlite3_vtab_rhs_value(P,J,V)
9286** inteface returns SQLITE_NOTFOUND if the right-hand side of the J-th
9287** constraint is not available. ^The sqlite3_vtab_rhs_value() interface
9288** can return an result code other than SQLITE_OK or SQLITE_NOTFOUND if
9289** something goes wrong.
9290**
9291** The sqlite3_vtab_rhs_value() interface is usually only successful if
9292** the right-hand operand of a constraint is a literal value in the original
9293** SQL statement. If the right-hand operand is an expression or a reference
9294** to some other column or a [host parameter], then sqlite3_vtab_rhs_value()
9295** will probably return [SQLITE_NOTFOUND].
9296**
9297** ^(Some constraints, such as [SQLITE_INDEX_CONSTRAINT_ISNULL] and
9298** [SQLITE_INDEX_CONSTRAINT_ISNOTNULL], have no right-hand operand. For such
9299** constraints, sqlite3_vtab_rhs_value() always returns SQLITE_NOTFOUND.)^
9300**
9301** ^The [sqlite3_value] object returned in *V is a protected sqlite3_value
9302** and remains valid for the duration of the xBestIndex method call.
9303** ^When xBestIndex returns, the sqlite3_value object returned by
9304** sqlite3_vtab_rhs_value() is automatically deallocated.
9305**
9306** The "_rhs_" in the name of this routine is an abbreviation for
9307** "Right-Hand Side".
9308*/
9309
9310/*
9311** CAPI3REF: Conflict resolution modes
9312** KEYWORDS: {conflict resolution mode}
9313**
9314** These constants are returned by [sqlite3_vtab_on_conflict()] to
9315** inform a [virtual table] implementation what the [ON CONFLICT] mode
9316** is for the SQL statement being evaluated.
9317**
9318** Note that the [SQLITE_IGNORE] constant is also used as a potential
9319** return value from the [sqlite3_set_authorizer()] callback and that
9320** [SQLITE_ABORT] is also a [result code].
9321*/
9322#define SQLITE_ROLLBACK 1
9323/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
9324#define SQLITE_FAIL 3
9325/* #define SQLITE_ABORT 4 // Also an error code */
9326#define SQLITE_REPLACE 5
9327
9328/*
9329** CAPI3REF: Prepared Statement Scan Status Opcodes
9330** KEYWORDS: {scanstatus options}
9331**
9332** The following constants can be used for the T parameter to the
9333** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a
9334** different metric for sqlite3_stmt_scanstatus() to return.
9335**
9336** When the value returned to V is a string, space to hold that string is
9337** managed by the prepared statement S and will be automatically freed when
9338** S is finalized.
9339**
9340** <dl>
9341** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
9342** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be
9343** set to the total number of times that the X-th loop has run.</dd>
9344**
9345** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
9346** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set
9347** to the total number of rows examined by all iterations of the X-th loop.</dd>
9348**
9349** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
9350** <dd>^The "double" variable pointed to by the V parameter will be set to the
9351** query planner's estimate for the average number of rows output from each
9352** iteration of the X-th loop. If the query planner's estimates was accurate,
9353** then this value will approximate the quotient NVISIT/NLOOP and the
9354** product of this value for all prior loops with the same SELECTID will
9355** be the NLOOP value for the current loop.
9356**
9357** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
9358** <dd>^The "const char *" variable pointed to by the V parameter will be set
9359** to a zero-terminated UTF-8 string containing the name of the index or table
9360** used for the X-th loop.
9361**
9362** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
9363** <dd>^The "const char *" variable pointed to by the V parameter will be set
9364** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
9365** description for the X-th loop.
9366**
9367** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
9368** <dd>^The "int" variable pointed to by the V parameter will be set to the
9369** "select-id" for the X-th loop. The select-id identifies which query or
9370** subquery the loop is part of. The main query has a select-id of zero.
9371** The select-id is the same value as is output in the first column
9372** of an [EXPLAIN QUERY PLAN] query.
9373** </dl>
9374*/
9375#define SQLITE_SCANSTAT_NLOOP 0
9376#define SQLITE_SCANSTAT_NVISIT 1
9377#define SQLITE_SCANSTAT_EST 2
9378#define SQLITE_SCANSTAT_NAME 3
9379#define SQLITE_SCANSTAT_EXPLAIN 4
9380#define SQLITE_SCANSTAT_SELECTID 5
9381
9382/*
9383** CAPI3REF: Prepared Statement Scan Status
9384** METHOD: sqlite3_stmt
9385**
9386** This interface returns information about the predicted and measured
9387** performance for pStmt. Advanced applications can use this
9388** interface to compare the predicted and the measured performance and
9389** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
9390**
9391** Since this interface is expected to be rarely used, it is only
9392** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
9393** compile-time option.
9394**
9395** The "iScanStatusOp" parameter determines which status information to return.
9396** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
9397** of this interface is undefined.
9398** ^The requested measurement is written into a variable pointed to by
9399** the "pOut" parameter.
9400** Parameter "idx" identifies the specific loop to retrieve statistics for.
9401** Loops are numbered starting from zero. ^If idx is out of range - less than
9402** zero or greater than or equal to the total number of loops used to implement
9403** the statement - a non-zero value is returned and the variable that pOut
9404** points to is unchanged.
9405**
9406** ^Statistics might not be available for all loops in all statements. ^In cases
9407** where there exist loops with no available statistics, this function behaves
9408** as if the loop did not exist - it returns non-zero and leave the variable
9409** that pOut points to unchanged.
9410**
9411** See also: [sqlite3_stmt_scanstatus_reset()]
9412*/
9413
9414/*
9415** CAPI3REF: Zero Scan-Status Counters
9416** METHOD: sqlite3_stmt
9417**
9418** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
9419**
9420** This API is only available if the library is built with pre-processor
9421** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
9422*/
9423
9424/*
9425** CAPI3REF: Flush caches to disk mid-transaction
9426** METHOD: sqlite3
9427**
9428** ^If a write-transaction is open on [database connection] D when the
9429** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
9430** pages in the pager-cache that are not currently in use are written out
9431** to disk. A dirty page may be in use if a database cursor created by an
9432** active SQL statement is reading from it, or if it is page 1 of a database
9433** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)]
9434** interface flushes caches for all schemas - "main", "temp", and
9435** any [attached] databases.
9436**
9437** ^If this function needs to obtain extra database locks before dirty pages
9438** can be flushed to disk, it does so. ^If those locks cannot be obtained
9439** immediately and there is a busy-handler callback configured, it is invoked
9440** in the usual manner. ^If the required lock still cannot be obtained, then
9441** the database is skipped and an attempt made to flush any dirty pages
9442** belonging to the next (if any) database. ^If any databases are skipped
9443** because locks cannot be obtained, but no other error occurs, this
9444** function returns SQLITE_BUSY.
9445**
9446** ^If any other error occurs while flushing dirty pages to disk (for
9447** example an IO error or out-of-memory condition), then processing is
9448** abandoned and an SQLite [error code] is returned to the caller immediately.
9449**
9450** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
9451**
9452** ^This function does not set the database handle error code or message
9453** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
9454*/
9455
9456/*
9457** CAPI3REF: The pre-update hook.
9458** METHOD: sqlite3
9459**
9460** ^These interfaces are only available if SQLite is compiled using the
9461** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
9462**
9463** ^The [sqlite3_preupdate_hook()] interface registers a callback function
9464** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
9465** on a database table.
9466** ^At most one preupdate hook may be registered at a time on a single
9467** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
9468** the previous setting.
9469** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
9470** with a NULL pointer as the second parameter.
9471** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
9472** the first parameter to callbacks.
9473**
9474** ^The preupdate hook only fires for changes to real database tables; the
9475** preupdate hook is not invoked for changes to [virtual tables] or to
9476** system tables like sqlite_sequence or sqlite_stat1.
9477**
9478** ^The second parameter to the preupdate callback is a pointer to
9479** the [database connection] that registered the preupdate hook.
9480** ^The third parameter to the preupdate callback is one of the constants
9481** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
9482** kind of update operation that is about to occur.
9483** ^(The fourth parameter to the preupdate callback is the name of the
9484** database within the database connection that is being modified. This
9485** will be "main" for the main database or "temp" for TEMP tables or
9486** the name given after the AS keyword in the [ATTACH] statement for attached
9487** databases.)^
9488** ^The fifth parameter to the preupdate callback is the name of the
9489** table that is being modified.
9490**
9491** For an UPDATE or DELETE operation on a [rowid table], the sixth
9492** parameter passed to the preupdate callback is the initial [rowid] of the
9493** row being modified or deleted. For an INSERT operation on a rowid table,
9494** or any operation on a WITHOUT ROWID table, the value of the sixth
9495** parameter is undefined. For an INSERT or UPDATE on a rowid table the
9496** seventh parameter is the final rowid value of the row being inserted
9497** or updated. The value of the seventh parameter passed to the callback
9498** function is not defined for operations on WITHOUT ROWID tables, or for
9499** DELETE operations on rowid tables.
9500**
9501** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
9502** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
9503** provide additional information about a preupdate event. These routines
9504** may only be called from within a preupdate callback. Invoking any of
9505** these routines from outside of a preupdate callback or with a
9506** [database connection] pointer that is different from the one supplied
9507** to the preupdate callback results in undefined and probably undesirable
9508** behavior.
9509**
9510** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
9511** in the row that is being inserted, updated, or deleted.
9512**
9513** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
9514** a [protected sqlite3_value] that contains the value of the Nth column of
9515** the table row before it is updated. The N parameter must be between 0
9516** and one less than the number of columns or the behavior will be
9517** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
9518** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
9519** behavior is undefined. The [sqlite3_value] that P points to
9520** will be destroyed when the preupdate callback returns.
9521**
9522** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
9523** a [protected sqlite3_value] that contains the value of the Nth column of
9524** the table row after it is updated. The N parameter must be between 0
9525** and one less than the number of columns or the behavior will be
9526** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
9527** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
9528** behavior is undefined. The [sqlite3_value] that P points to
9529** will be destroyed when the preupdate callback returns.
9530**
9531** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
9532** callback was invoked as a result of a direct insert, update, or delete
9533** operation; or 1 for inserts, updates, or deletes invoked by top-level
9534** triggers; or 2 for changes resulting from triggers called by top-level
9535** triggers; and so forth.
9536**
9537** When the [sqlite3_blob_write()] API is used to update a blob column,
9538** the pre-update hook is invoked with SQLITE_DELETE. This is because the
9539** in this case the new values are not available. In this case, when a
9540** callback made with op==SQLITE_DELETE is actuall a write using the
9541** sqlite3_blob_write() API, the [sqlite3_preupdate_blobwrite()] returns
9542** the index of the column being written. In other cases, where the
9543** pre-update hook is being invoked for some other reason, including a
9544** regular DELETE, sqlite3_preupdate_blobwrite() returns -1.
9545**
9546** See also: [sqlite3_update_hook()]
9547*/
9548#if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
9549#endif
9550
9551/*
9552** CAPI3REF: Low-level system error code
9553** METHOD: sqlite3
9554**
9555** ^Attempt to return the underlying operating system error code or error
9556** number that caused the most recent I/O error or failure to open a file.
9557** The return value is OS-dependent. For example, on unix systems, after
9558** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
9559** called to get back the underlying "errno" that caused the problem, such
9560** as ENOSPC, EAUTH, EISDIR, and so forth.
9561*/
9562
9563/*
9564** CAPI3REF: Database Snapshot
9565** KEYWORDS: {snapshot} {sqlite3_snapshot}
9566**
9567** An instance of the snapshot object records the state of a [WAL mode]
9568** database for some specific point in history.
9569**
9570** In [WAL mode], multiple [database connections] that are open on the
9571** same database file can each be reading a different historical version
9572** of the database file. When a [database connection] begins a read
9573** transaction, that connection sees an unchanging copy of the database
9574** as it existed for the point in time when the transaction first started.
9575** Subsequent changes to the database from other connections are not seen
9576** by the reader until a new read transaction is started.
9577**
9578** The sqlite3_snapshot object records state information about an historical
9579** version of the database file so that it is possible to later open a new read
9580** transaction that sees that historical version of the database rather than
9581** the most recent version.
9582*/
9583typedef struct sqlite3_snapshot {
9584 unsigned char hidden[48];
9585} sqlite3_snapshot;
9586
9587/*
9588** CAPI3REF: Record A Database Snapshot
9589** CONSTRUCTOR: sqlite3_snapshot
9590**
9591** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
9592** new [sqlite3_snapshot] object that records the current state of
9593** schema S in database connection D. ^On success, the
9594** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
9595** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
9596** If there is not already a read-transaction open on schema S when
9597** this function is called, one is opened automatically.
9598**
9599** The following must be true for this function to succeed. If any of
9600** the following statements are false when sqlite3_snapshot_get() is
9601** called, SQLITE_ERROR is returned. The final value of *P is undefined
9602** in this case.
9603**
9604** <ul>
9605** <li> The database handle must not be in [autocommit mode].
9606**
9607** <li> Schema S of [database connection] D must be a [WAL mode] database.
9608**
9609** <li> There must not be a write transaction open on schema S of database
9610** connection D.
9611**
9612** <li> One or more transactions must have been written to the current wal
9613** file since it was created on disk (by any connection). This means
9614** that a snapshot cannot be taken on a wal mode database with no wal
9615** file immediately after it is first opened. At least one transaction
9616** must be written to it first.
9617** </ul>
9618**
9619** This function may also return SQLITE_NOMEM. If it is called with the
9620** database handle in autocommit mode but fails for some other reason,
9621** whether or not a read transaction is opened on schema S is undefined.
9622**
9623** The [sqlite3_snapshot] object returned from a successful call to
9624** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
9625** to avoid a memory leak.
9626**
9627** The [sqlite3_snapshot_get()] interface is only available when the
9628** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
9629*/
9630
9631/*
9632** CAPI3REF: Start a read transaction on an historical snapshot
9633** METHOD: sqlite3_snapshot
9634**
9635** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read
9636** transaction or upgrades an existing one for schema S of
9637** [database connection] D such that the read transaction refers to
9638** historical [snapshot] P, rather than the most recent change to the
9639** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK
9640** on success or an appropriate [error code] if it fails.
9641**
9642** ^In order to succeed, the database connection must not be in
9643** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there
9644** is already a read transaction open on schema S, then the database handle
9645** must have no active statements (SELECT statements that have been passed
9646** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()).
9647** SQLITE_ERROR is returned if either of these conditions is violated, or
9648** if schema S does not exist, or if the snapshot object is invalid.
9649**
9650** ^A call to sqlite3_snapshot_open() will fail to open if the specified
9651** snapshot has been overwritten by a [checkpoint]. In this case
9652** SQLITE_ERROR_SNAPSHOT is returned.
9653**
9654** If there is already a read transaction open when this function is
9655** invoked, then the same read transaction remains open (on the same
9656** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT
9657** is returned. If another error code - for example SQLITE_PROTOCOL or an
9658** SQLITE_IOERR error code - is returned, then the final state of the
9659** read transaction is undefined. If SQLITE_OK is returned, then the
9660** read transaction is now open on database snapshot P.
9661**
9662** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
9663** database connection D does not know that the database file for
9664** schema S is in [WAL mode]. A database connection might not know
9665** that the database file is in [WAL mode] if there has been no prior
9666** I/O on that database connection, or if the database entered [WAL mode]
9667** after the most recent I/O on the database connection.)^
9668** (Hint: Run "[PRAGMA application_id]" against a newly opened
9669** database connection in order to make it ready to use snapshots.)
9670**
9671** The [sqlite3_snapshot_open()] interface is only available when the
9672** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
9673*/
9674
9675/*
9676** CAPI3REF: Destroy a snapshot
9677** DESTRUCTOR: sqlite3_snapshot
9678**
9679** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
9680** The application must eventually free every [sqlite3_snapshot] object
9681** using this routine to avoid a memory leak.
9682**
9683** The [sqlite3_snapshot_free()] interface is only available when the
9684** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
9685*/
9686
9687/*
9688** CAPI3REF: Compare the ages of two snapshot handles.
9689** METHOD: sqlite3_snapshot
9690**
9691** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
9692** of two valid snapshot handles.
9693**
9694** If the two snapshot handles are not associated with the same database
9695** file, the result of the comparison is undefined.
9696**
9697** Additionally, the result of the comparison is only valid if both of the
9698** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
9699** last time the wal file was deleted. The wal file is deleted when the
9700** database is changed back to rollback mode or when the number of database
9701** clients drops to zero. If either snapshot handle was obtained before the
9702** wal file was last deleted, the value returned by this function
9703** is undefined.
9704**
9705** Otherwise, this API returns a negative value if P1 refers to an older
9706** snapshot than P2, zero if the two handles refer to the same database
9707** snapshot, and a positive value if P1 is a newer snapshot than P2.
9708**
9709** This interface is only available if SQLite is compiled with the
9710** [SQLITE_ENABLE_SNAPSHOT] option.
9711*/
9712
9713/*
9714** CAPI3REF: Recover snapshots from a wal file
9715** METHOD: sqlite3_snapshot
9716**
9717** If a [WAL file] remains on disk after all database connections close
9718** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control]
9719** or because the last process to have the database opened exited without
9720** calling [sqlite3_close()]) and a new connection is subsequently opened
9721** on that database and [WAL file], the [sqlite3_snapshot_open()] interface
9722** will only be able to open the last transaction added to the WAL file
9723** even though the WAL file contains other valid transactions.
9724**
9725** This function attempts to scan the WAL file associated with database zDb
9726** of database handle db and make all valid snapshots available to
9727** sqlite3_snapshot_open(). It is an error if there is already a read
9728** transaction open on the database, or if the database is not a WAL mode
9729** database.
9730**
9731** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
9732**
9733** This interface is only available if SQLite is compiled with the
9734** [SQLITE_ENABLE_SNAPSHOT] option.
9735*/
9736
9737/*
9738** CAPI3REF: Serialize a database
9739**
9740** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory
9741** that is a serialization of the S database on [database connection] D.
9742** If P is not a NULL pointer, then the size of the database in bytes
9743** is written into *P.
9744**
9745** For an ordinary on-disk database file, the serialization is just a
9746** copy of the disk file. For an in-memory database or a "TEMP" database,
9747** the serialization is the same sequence of bytes which would be written
9748** to disk if that database where backed up to disk.
9749**
9750** The usual case is that sqlite3_serialize() copies the serialization of
9751** the database into memory obtained from [sqlite3_malloc64()] and returns
9752** a pointer to that memory. The caller is responsible for freeing the
9753** returned value to avoid a memory leak. However, if the F argument
9754** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
9755** are made, and the sqlite3_serialize() function will return a pointer
9756** to the contiguous memory representation of the database that SQLite
9757** is currently using for that database, or NULL if the no such contiguous
9758** memory representation of the database exists. A contiguous memory
9759** representation of the database will usually only exist if there has
9760** been a prior call to [sqlite3_deserialize(D,S,...)] with the same
9761** values of D and S.
9762** The size of the database is written into *P even if the
9763** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
9764** of the database exists.
9765**
9766** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
9767** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
9768** allocation error occurs.
9769**
9770** This interface is omitted if SQLite is compiled with the
9771** [SQLITE_OMIT_DESERIALIZE] option.
9772*/
9773
9774/*
9775** CAPI3REF: Flags for sqlite3_serialize
9776**
9777** Zero or more of the following constants can be OR-ed together for
9778** the F argument to [sqlite3_serialize(D,S,P,F)].
9779**
9780** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return
9781** a pointer to contiguous in-memory database that it is currently using,
9782** without making a copy of the database. If SQLite is not currently using
9783** a contiguous in-memory database, then this option causes
9784** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be
9785** using a contiguous in-memory database if it has been initialized by a
9786** prior call to [sqlite3_deserialize()].
9787*/
9788#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */
9789
9790/*
9791** CAPI3REF: Deserialize a database
9792**
9793** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
9794** [database connection] D to disconnect from database S and then
9795** reopen S as an in-memory database based on the serialization contained
9796** in P. The serialized database P is N bytes in size. M is the size of
9797** the buffer P, which might be larger than N. If M is larger than N, and
9798** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
9799** permitted to add content to the in-memory database as long as the total
9800** size does not exceed M bytes.
9801**
9802** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
9803** invoke sqlite3_free() on the serialization buffer when the database
9804** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
9805** SQLite will try to increase the buffer size using sqlite3_realloc64()
9806** if writes on the database cause it to grow larger than M bytes.
9807**
9808** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
9809** database is currently in a read transaction or is involved in a backup
9810** operation.
9811**
9812** It is not possible to deserialized into the TEMP database. If the
9813** S argument to sqlite3_deserialize(D,S,P,N,M,F) is "temp" then the
9814** function returns SQLITE_ERROR.
9815**
9816** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
9817** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
9818** [sqlite3_free()] is invoked on argument P prior to returning.
9819**
9820** This interface is omitted if SQLite is compiled with the
9821** [SQLITE_OMIT_DESERIALIZE] option.
9822*/
9823
9824/*
9825** CAPI3REF: Flags for sqlite3_deserialize()
9826**
9827** The following are allowed values for 6th argument (the F argument) to
9828** the [sqlite3_deserialize(D,S,P,N,M,F)] interface.
9829**
9830** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
9831** in the P argument is held in memory obtained from [sqlite3_malloc64()]
9832** and that SQLite should take ownership of this memory and automatically
9833** free it when it has finished using it. Without this flag, the caller
9834** is responsible for freeing any dynamically allocated memory.
9835**
9836** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
9837** grow the size of the database using calls to [sqlite3_realloc64()]. This
9838** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
9839** Without this flag, the deserialized database cannot increase in size beyond
9840** the number of bytes specified by the M parameter.
9841**
9842** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
9843** should be treated as read-only.
9844*/
9845#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
9846#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */
9847#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */
9848
9849/*
9850** Undo the hack that converts floating point types to integer for
9851** builds on processors without floating point support.
9852*/
9853#ifdef SQLITE_OMIT_FLOATING_POINT
9854# undef double
9855#endif
9856
9857#ifdef __cplusplus
9858} /* End of the 'extern "C"' block */
9859#endif
9860#endif /* SQLITE3_H */
9861
9862/******** Begin file sqlite3rtree.h *********/
9863/*
9864** 2010 August 30
9865**
9866** The author disclaims copyright to this source code. In place of
9867** a legal notice, here is a blessing:
9868**
9869** May you do good and not evil.
9870** May you find forgiveness for yourself and forgive others.
9871** May you share freely, never taking more than you give.
9872**
9873*************************************************************************
9874*/
9875
9876#ifndef _SQLITE3RTREE_H_
9877#define _SQLITE3RTREE_H_
9878
9879
9880#ifdef __cplusplus
9881extern "C" {
9882#endif
9883
9884typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
9885typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
9886
9887/* The double-precision datatype used by RTree depends on the
9888** SQLITE_RTREE_INT_ONLY compile-time option.
9889*/
9890#ifdef SQLITE_RTREE_INT_ONLY
9891 typedef sqlite3_int64 sqlite3_rtree_dbl;
9892#else
9893 typedef double sqlite3_rtree_dbl;
9894#endif
9895
9896/*
9897** Register a geometry callback named zGeom that can be used as part of an
9898** R-Tree geometry query as follows:
9899**
9900** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
9901*/
9902
9903
9904/*
9905** A pointer to a structure of the following type is passed as the first
9906** argument to callbacks registered using rtree_geometry_callback().
9907*/
9908struct sqlite3_rtree_geometry {
9909 void *pContext; /* Copy of pContext passed to s_r_g_c() */
9910 int nParam; /* Size of array aParam[] */
9911 sqlite3_rtree_dbl *aParam; /* Parameters passed to SQL geom function */
9912 void *pUser; /* Callback implementation user data */
9913 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */
9914};
9915
9916/*
9917** Register a 2nd-generation geometry callback named zScore that can be
9918** used as part of an R-Tree geometry query as follows:
9919**
9920** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
9921*/
9922
9923
9924/*
9925** A pointer to a structure of the following type is passed as the
9926** argument to scored geometry callback registered using
9927** sqlite3_rtree_query_callback().
9928**
9929** Note that the first 5 fields of this structure are identical to
9930** sqlite3_rtree_geometry. This structure is a subclass of
9931** sqlite3_rtree_geometry.
9932*/
9933struct sqlite3_rtree_query_info {
9934 void *pContext; /* pContext from when function registered */
9935 int nParam; /* Number of function parameters */
9936 sqlite3_rtree_dbl *aParam; /* value of function parameters */
9937 void *pUser; /* callback can use this, if desired */
9938 void (*xDelUser)(void*); /* function to free pUser */
9939 sqlite3_rtree_dbl *aCoord; /* Coordinates of node or entry to check */
9940 unsigned int *anQueue; /* Number of pending entries in the queue */
9941 int nCoord; /* Number of coordinates */
9942 int iLevel; /* Level of current node or entry */
9943 int mxLevel; /* The largest iLevel value in the tree */
9944 sqlite3_int64 iRowid; /* Rowid for current entry */
9945 sqlite3_rtree_dbl rParentScore; /* Score of parent node */
9946 int eParentWithin; /* Visibility of parent node */
9947 int eWithin; /* OUT: Visibility */
9948 sqlite3_rtree_dbl rScore; /* OUT: Write the score here */
9949 /* The following fields are only available in 3.8.11 and later */
9950 sqlite3_value **apSqlParam; /* Original SQL values of parameters */
9951};
9952
9953/*
9954** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
9955*/
9956#define NOT_WITHIN 0 /* Object completely outside of query region */
9957#define PARTLY_WITHIN 1 /* Object partially overlaps query region */
9958#define FULLY_WITHIN 2 /* Object fully contained within query region */
9959
9960
9961#ifdef __cplusplus
9962} /* end of the 'extern "C"' block */
9963#endif
9964
9965#endif /* ifndef _SQLITE3RTREE_H_ */
9966
9967/******** End of sqlite3rtree.h *********/
9968/******** Begin file sqlite3session.h *********/
9969
9970#if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
9971#define __SQLITESESSION_H_ 1
9972
9973/*
9974** Make sure we can call this stuff from C++.
9975*/
9976#ifdef __cplusplus
9977extern "C" {
9978#endif
9979
9980
9981/*
9982** CAPI3REF: Session Object Handle
9983**
9984** An instance of this object is a [session] that can be used to
9985** record changes to a database.
9986*/
9987typedef struct sqlite3_session sqlite3_session;
9988
9989/*
9990** CAPI3REF: Changeset Iterator Handle
9991**
9992** An instance of this object acts as a cursor for iterating
9993** over the elements of a [changeset] or [patchset].
9994*/
9995typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
9996
9997/*
9998** CAPI3REF: Create A New Session Object
9999** CONSTRUCTOR: sqlite3_session
10000**
10001** Create a new session object attached to database handle db. If successful,
10002** a pointer to the new object is written to *ppSession and SQLITE_OK is
10003** returned. If an error occurs, *ppSession is set to NULL and an SQLite
10004** error code (e.g. SQLITE_NOMEM) is returned.
10005**
10006** It is possible to create multiple session objects attached to a single
10007** database handle.
10008**
10009** Session objects created using this function should be deleted using the
10010** [sqlite3session_delete()] function before the database handle that they
10011** are attached to is itself closed. If the database handle is closed before
10012** the session object is deleted, then the results of calling any session
10013** module function, including [sqlite3session_delete()] on the session object
10014** are undefined.
10015**
10016** Because the session module uses the [sqlite3_preupdate_hook()] API, it
10017** is not possible for an application to register a pre-update hook on a
10018** database handle that has one or more session objects attached. Nor is
10019** it possible to create a session object attached to a database handle for
10020** which a pre-update hook is already defined. The results of attempting
10021** either of these things are undefined.
10022**
10023** The session object will be used to create changesets for tables in
10024** database zDb, where zDb is either "main", or "temp", or the name of an
10025** attached database. It is not an error if database zDb is not attached
10026** to the database when the session object is created.
10027*/
10028
10029/*
10030** CAPI3REF: Delete A Session Object
10031** DESTRUCTOR: sqlite3_session
10032**
10033** Delete a session object previously allocated using
10034** [sqlite3session_create()]. Once a session object has been deleted, the
10035** results of attempting to use pSession with any other session module
10036** function are undefined.
10037**
10038** Session objects must be deleted before the database handle to which they
10039** are attached is closed. Refer to the documentation for
10040** [sqlite3session_create()] for details.
10041*/
10042
10043/*
10044** CAPIREF: Conigure a Session Object
10045** METHOD: sqlite3_session
10046**
10047** This method is used to configure a session object after it has been
10048** created. At present the only valid value for the second parameter is
10049** [SQLITE_SESSION_OBJCONFIG_SIZE].
10050**
10051** Arguments for sqlite3session_object_config()
10052**
10053** The following values may passed as the the 4th parameter to
10054** sqlite3session_object_config().
10055**
10056** <dt>SQLITE_SESSION_OBJCONFIG_SIZE <dd>
10057** This option is used to set, clear or query the flag that enables
10058** the [sqlite3session_changeset_size()] API. Because it imposes some
10059** computational overhead, this API is disabled by default. Argument
10060** pArg must point to a value of type (int). If the value is initially
10061** 0, then the sqlite3session_changeset_size() API is disabled. If it
10062** is greater than 0, then the same API is enabled. Or, if the initial
10063** value is less than zero, no change is made. In all cases the (int)
10064** variable is set to 1 if the sqlite3session_changeset_size() API is
10065** enabled following the current call, or 0 otherwise.
10066**
10067** It is an error (SQLITE_MISUSE) to attempt to modify this setting after
10068** the first table has been attached to the session object.
10069*/
10070
10071/*
10072*/
10073#define SQLITE_SESSION_OBJCONFIG_SIZE 1
10074
10075/*
10076** CAPI3REF: Enable Or Disable A Session Object
10077** METHOD: sqlite3_session
10078**
10079** Enable or disable the recording of changes by a session object. When
10080** enabled, a session object records changes made to the database. When
10081** disabled - it does not. A newly created session object is enabled.
10082** Refer to the documentation for [sqlite3session_changeset()] for further
10083** details regarding how enabling and disabling a session object affects
10084** the eventual changesets.
10085**
10086** Passing zero to this function disables the session. Passing a value
10087** greater than zero enables it. Passing a value less than zero is a
10088** no-op, and may be used to query the current state of the session.
10089**
10090** The return value indicates the final state of the session object: 0 if
10091** the session is disabled, or 1 if it is enabled.
10092*/
10093
10094/*
10095** CAPI3REF: Set Or Clear the Indirect Change Flag
10096** METHOD: sqlite3_session
10097**
10098** Each change recorded by a session object is marked as either direct or
10099** indirect. A change is marked as indirect if either:
10100**
10101** <ul>
10102** <li> The session object "indirect" flag is set when the change is
10103** made, or
10104** <li> The change is made by an SQL trigger or foreign key action
10105** instead of directly as a result of a users SQL statement.
10106** </ul>
10107**
10108** If a single row is affected by more than one operation within a session,
10109** then the change is considered indirect if all operations meet the criteria
10110** for an indirect change above, or direct otherwise.
10111**
10112** This function is used to set, clear or query the session object indirect
10113** flag. If the second argument passed to this function is zero, then the
10114** indirect flag is cleared. If it is greater than zero, the indirect flag
10115** is set. Passing a value less than zero does not modify the current value
10116** of the indirect flag, and may be used to query the current state of the
10117** indirect flag for the specified session object.
10118**
10119** The return value indicates the final state of the indirect flag: 0 if
10120** it is clear, or 1 if it is set.
10121*/
10122
10123/*
10124** CAPI3REF: Attach A Table To A Session Object
10125** METHOD: sqlite3_session
10126**
10127** If argument zTab is not NULL, then it is the name of a table to attach
10128** to the session object passed as the first argument. All subsequent changes
10129** made to the table while the session object is enabled will be recorded. See
10130** documentation for [sqlite3session_changeset()] for further details.
10131**
10132** Or, if argument zTab is NULL, then changes are recorded for all tables
10133** in the database. If additional tables are added to the database (by
10134** executing "CREATE TABLE" statements) after this call is made, changes for
10135** the new tables are also recorded.
10136**
10137** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
10138** defined as part of their CREATE TABLE statement. It does not matter if the
10139** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
10140** KEY may consist of a single column, or may be a composite key.
10141**
10142** It is not an error if the named table does not exist in the database. Nor
10143** is it an error if the named table does not have a PRIMARY KEY. However,
10144** no changes will be recorded in either of these scenarios.
10145**
10146** Changes are not recorded for individual rows that have NULL values stored
10147** in one or more of their PRIMARY KEY columns.
10148**
10149** SQLITE_OK is returned if the call completes without error. Or, if an error
10150** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
10151**
10152** <h3>Special sqlite_stat1 Handling</h3>
10153**
10154** As of SQLite version 3.22.0, the "sqlite_stat1" table is an exception to
10155** some of the rules above. In SQLite, the schema of sqlite_stat1 is:
10156** <pre>
10157** &nbsp; CREATE TABLE sqlite_stat1(tbl,idx,stat)
10158** </pre>
10159**
10160** Even though sqlite_stat1 does not have a PRIMARY KEY, changes are
10161** recorded for it as if the PRIMARY KEY is (tbl,idx). Additionally, changes
10162** are recorded for rows for which (idx IS NULL) is true. However, for such
10163** rows a zero-length blob (SQL value X'') is stored in the changeset or
10164** patchset instead of a NULL value. This allows such changesets to be
10165** manipulated by legacy implementations of sqlite3changeset_invert(),
10166** concat() and similar.
10167**
10168** The sqlite3changeset_apply() function automatically converts the
10169** zero-length blob back to a NULL value when updating the sqlite_stat1
10170** table. However, if the application calls sqlite3changeset_new(),
10171** sqlite3changeset_old() or sqlite3changeset_conflict on a changeset
10172** iterator directly (including on a changeset iterator passed to a
10173** conflict-handler callback) then the X'' value is returned. The application
10174** must translate X'' to NULL itself if required.
10175**
10176** Legacy (older than 3.22.0) versions of the sessions module cannot capture
10177** changes made to the sqlite_stat1 table. Legacy versions of the
10178** sqlite3changeset_apply() function silently ignore any modifications to the
10179** sqlite_stat1 table that are part of a changeset or patchset.
10180*/
10181
10182/*
10183** CAPI3REF: Set a table filter on a Session Object.
10184** METHOD: sqlite3_session
10185**
10186** The second argument (xFilter) is the "filter callback". For changes to rows
10187** in tables that are not attached to the Session object, the filter is called
10188** to determine whether changes to the table's rows should be tracked or not.
10189** If xFilter returns 0, changes are not tracked. Note that once a table is
10190** attached, xFilter will not be called again.
10191*/
10192
10193/*
10194** CAPI3REF: Generate A Changeset From A Session Object
10195** METHOD: sqlite3_session
10196**
10197** Obtain a changeset containing changes to the tables attached to the
10198** session object passed as the first argument. If successful,
10199** set *ppChangeset to point to a buffer containing the changeset
10200** and *pnChangeset to the size of the changeset in bytes before returning
10201** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
10202** zero and return an SQLite error code.
10203**
10204** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
10205** each representing a change to a single row of an attached table. An INSERT
10206** change contains the values of each field of a new database row. A DELETE
10207** contains the original values of each field of a deleted database row. An
10208** UPDATE change contains the original values of each field of an updated
10209** database row along with the updated values for each updated non-primary-key
10210** column. It is not possible for an UPDATE change to represent a change that
10211** modifies the values of primary key columns. If such a change is made, it
10212** is represented in a changeset as a DELETE followed by an INSERT.
10213**
10214** Changes are not recorded for rows that have NULL values stored in one or
10215** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
10216** no corresponding change is present in the changesets returned by this
10217** function. If an existing row with one or more NULL values stored in
10218** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
10219** only an INSERT is appears in the changeset. Similarly, if an existing row
10220** with non-NULL PRIMARY KEY values is updated so that one or more of its
10221** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
10222** DELETE change only.
10223**
10224** The contents of a changeset may be traversed using an iterator created
10225** using the [sqlite3changeset_start()] API. A changeset may be applied to
10226** a database with a compatible schema using the [sqlite3changeset_apply()]
10227** API.
10228**
10229** Within a changeset generated by this function, all changes related to a
10230** single table are grouped together. In other words, when iterating through
10231** a changeset or when applying a changeset to a database, all changes related
10232** to a single table are processed before moving on to the next table. Tables
10233** are sorted in the same order in which they were attached (or auto-attached)
10234** to the sqlite3_session object. The order in which the changes related to
10235** a single table are stored is undefined.
10236**
10237** Following a successful call to this function, it is the responsibility of
10238** the caller to eventually free the buffer that *ppChangeset points to using
10239** [sqlite3_free()].
10240**
10241** <h3>Changeset Generation</h3>
10242**
10243** Once a table has been attached to a session object, the session object
10244** records the primary key values of all new rows inserted into the table.
10245** It also records the original primary key and other column values of any
10246** deleted or updated rows. For each unique primary key value, data is only
10247** recorded once - the first time a row with said primary key is inserted,
10248** updated or deleted in the lifetime of the session.
10249**
10250** There is one exception to the previous paragraph: when a row is inserted,
10251** updated or deleted, if one or more of its primary key columns contain a
10252** NULL value, no record of the change is made.
10253**
10254** The session object therefore accumulates two types of records - those
10255** that consist of primary key values only (created when the user inserts
10256** a new record) and those that consist of the primary key values and the
10257** original values of other table columns (created when the users deletes
10258** or updates a record).
10259**
10260** When this function is called, the requested changeset is created using
10261** both the accumulated records and the current contents of the database
10262** file. Specifically:
10263**
10264** <ul>
10265** <li> For each record generated by an insert, the database is queried
10266** for a row with a matching primary key. If one is found, an INSERT
10267** change is added to the changeset. If no such row is found, no change
10268** is added to the changeset.
10269**
10270** <li> For each record generated by an update or delete, the database is
10271** queried for a row with a matching primary key. If such a row is
10272** found and one or more of the non-primary key fields have been
10273** modified from their original values, an UPDATE change is added to
10274** the changeset. Or, if no such row is found in the table, a DELETE
10275** change is added to the changeset. If there is a row with a matching
10276** primary key in the database, but all fields contain their original
10277** values, no change is added to the changeset.
10278** </ul>
10279**
10280** This means, amongst other things, that if a row is inserted and then later
10281** deleted while a session object is active, neither the insert nor the delete
10282** will be present in the changeset. Or if a row is deleted and then later a
10283** row with the same primary key values inserted while a session object is
10284** active, the resulting changeset will contain an UPDATE change instead of
10285** a DELETE and an INSERT.
10286**
10287** When a session object is disabled (see the [sqlite3session_enable()] API),
10288** it does not accumulate records when rows are inserted, updated or deleted.
10289** This may appear to have some counter-intuitive effects if a single row
10290** is written to more than once during a session. For example, if a row
10291** is inserted while a session object is enabled, then later deleted while
10292** the same session object is disabled, no INSERT record will appear in the
10293** changeset, even though the delete took place while the session was disabled.
10294** Or, if one field of a row is updated while a session is disabled, and
10295** another field of the same row is updated while the session is enabled, the
10296** resulting changeset will contain an UPDATE change that updates both fields.
10297*/
10298
10299/*
10300** CAPI3REF: Return An Upper-limit For The Size Of The Changeset
10301** METHOD: sqlite3_session
10302**
10303** By default, this function always returns 0. For it to return
10304** a useful result, the sqlite3_session object must have been configured
10305** to enable this API using sqlite3session_object_config() with the
10306** SQLITE_SESSION_OBJCONFIG_SIZE verb.
10307**
10308** When enabled, this function returns an upper limit, in bytes, for the size
10309** of the changeset that might be produced if sqlite3session_changeset() were
10310** called. The final changeset size might be equal to or smaller than the
10311** size in bytes returned by this function.
10312*/
10313
10314/*
10315** CAPI3REF: Load The Difference Between Tables Into A Session
10316** METHOD: sqlite3_session
10317**
10318** If it is not already attached to the session object passed as the first
10319** argument, this function attaches table zTbl in the same manner as the
10320** [sqlite3session_attach()] function. If zTbl does not exist, or if it
10321** does not have a primary key, this function is a no-op (but does not return
10322** an error).
10323**
10324** Argument zFromDb must be the name of a database ("main", "temp" etc.)
10325** attached to the same database handle as the session object that contains
10326** a table compatible with the table attached to the session by this function.
10327** A table is considered compatible if it:
10328**
10329** <ul>
10330** <li> Has the same name,
10331** <li> Has the same set of columns declared in the same order, and
10332** <li> Has the same PRIMARY KEY definition.
10333** </ul>
10334**
10335** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
10336** are compatible but do not have any PRIMARY KEY columns, it is not an error
10337** but no changes are added to the session object. As with other session
10338** APIs, tables without PRIMARY KEYs are simply ignored.
10339**
10340** This function adds a set of changes to the session object that could be
10341** used to update the table in database zFrom (call this the "from-table")
10342** so that its content is the same as the table attached to the session
10343** object (call this the "to-table"). Specifically:
10344**
10345** <ul>
10346** <li> For each row (primary key) that exists in the to-table but not in
10347** the from-table, an INSERT record is added to the session object.
10348**
10349** <li> For each row (primary key) that exists in the to-table but not in
10350** the from-table, a DELETE record is added to the session object.
10351**
10352** <li> For each row (primary key) that exists in both tables, but features
10353** different non-PK values in each, an UPDATE record is added to the
10354** session.
10355** </ul>
10356**
10357** To clarify, if this function is called and then a changeset constructed
10358** using [sqlite3session_changeset()], then after applying that changeset to
10359** database zFrom the contents of the two compatible tables would be
10360** identical.
10361**
10362** It an error if database zFrom does not exist or does not contain the
10363** required compatible table.
10364**
10365** If the operation is successful, SQLITE_OK is returned. Otherwise, an SQLite
10366** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
10367** may be set to point to a buffer containing an English language error
10368** message. It is the responsibility of the caller to free this buffer using
10369** sqlite3_free().
10370*/
10371
10372
10373/*
10374** CAPI3REF: Generate A Patchset From A Session Object
10375** METHOD: sqlite3_session
10376**
10377** The differences between a patchset and a changeset are that:
10378**
10379** <ul>
10380** <li> DELETE records consist of the primary key fields only. The
10381** original values of other fields are omitted.
10382** <li> The original values of any modified fields are omitted from
10383** UPDATE records.
10384** </ul>
10385**
10386** A patchset blob may be used with up to date versions of all
10387** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(),
10388** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
10389** attempting to use a patchset blob with old versions of the
10390** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error.
10391**
10392** Because the non-primary key "old.*" fields are omitted, no
10393** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
10394** is passed to the sqlite3changeset_apply() API. Other conflict types work
10395** in the same way as for changesets.
10396**
10397** Changes within a patchset are ordered in the same way as for changesets
10398** generated by the sqlite3session_changeset() function (i.e. all changes for
10399** a single table are grouped together, tables appear in the order in which
10400** they were attached to the session object).
10401*/
10402
10403/*
10404** CAPI3REF: Test if a changeset has recorded any changes.
10405**
10406** Return non-zero if no changes to attached tables have been recorded by
10407** the session object passed as the first argument. Otherwise, if one or
10408** more changes have been recorded, return zero.
10409**
10410** Even if this function returns zero, it is possible that calling
10411** [sqlite3session_changeset()] on the session handle may still return a
10412** changeset that contains no changes. This can happen when a row in
10413** an attached table is modified and then later on the original values
10414** are restored. However, if this function returns non-zero, then it is
10415** guaranteed that a call to sqlite3session_changeset() will return a
10416** changeset containing zero changes.
10417*/
10418
10419/*
10420** CAPI3REF: Query for the amount of heap memory used by a session object.
10421**
10422** This API returns the total amount of heap memory in bytes currently
10423** used by the session object passed as the only argument.
10424*/
10425
10426/*
10427** CAPI3REF: Create An Iterator To Traverse A Changeset
10428** CONSTRUCTOR: sqlite3_changeset_iter
10429**
10430** Create an iterator used to iterate through the contents of a changeset.
10431** If successful, *pp is set to point to the iterator handle and SQLITE_OK
10432** is returned. Otherwise, if an error occurs, *pp is set to zero and an
10433** SQLite error code is returned.
10434**
10435** The following functions can be used to advance and query a changeset
10436** iterator created by this function:
10437**
10438** <ul>
10439** <li> [sqlite3changeset_next()]
10440** <li> [sqlite3changeset_op()]
10441** <li> [sqlite3changeset_new()]
10442** <li> [sqlite3changeset_old()]
10443** </ul>
10444**
10445** It is the responsibility of the caller to eventually destroy the iterator
10446** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
10447** changeset (pChangeset) must remain valid until after the iterator is
10448** destroyed.
10449**
10450** Assuming the changeset blob was created by one of the
10451** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
10452** [sqlite3changeset_invert()] functions, all changes within the changeset
10453** that apply to a single table are grouped together. This means that when
10454** an application iterates through a changeset using an iterator created by
10455** this function, all changes that relate to a single table are visited
10456** consecutively. There is no chance that the iterator will visit a change
10457** the applies to table X, then one for table Y, and then later on visit
10458** another change for table X.
10459**
10460** The behavior of sqlite3changeset_start_v2() and its streaming equivalent
10461** may be modified by passing a combination of
10462** [SQLITE_CHANGESETSTART_INVERT | supported flags] as the 4th parameter.
10463**
10464** Note that the sqlite3changeset_start_v2() API is still <b>experimental</b>
10465** and therefore subject to change.
10466*/
10467
10468/*
10469** CAPI3REF: Flags for sqlite3changeset_start_v2
10470**
10471** The following flags may passed via the 4th parameter to
10472** [sqlite3changeset_start_v2] and [sqlite3changeset_start_v2_strm]:
10473**
10474** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
10475** Invert the changeset while iterating through it. This is equivalent to
10476** inverting a changeset using sqlite3changeset_invert() before applying it.
10477** It is an error to specify this flag with a patchset.
10478*/
10479#define SQLITE_CHANGESETSTART_INVERT 0x0002
10480
10481
10482/*
10483** CAPI3REF: Advance A Changeset Iterator
10484** METHOD: sqlite3_changeset_iter
10485**
10486** This function may only be used with iterators created by the function
10487** [sqlite3changeset_start()]. If it is called on an iterator passed to
10488** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
10489** is returned and the call has no effect.
10490**
10491** Immediately after an iterator is created by sqlite3changeset_start(), it
10492** does not point to any change in the changeset. Assuming the changeset
10493** is not empty, the first call to this function advances the iterator to
10494** point to the first change in the changeset. Each subsequent call advances
10495** the iterator to point to the next change in the changeset (if any). If
10496** no error occurs and the iterator points to a valid change after a call
10497** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned.
10498** Otherwise, if all changes in the changeset have already been visited,
10499** SQLITE_DONE is returned.
10500**
10501** If an error occurs, an SQLite error code is returned. Possible error
10502** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or
10503** SQLITE_NOMEM.
10504*/
10505
10506/*
10507** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
10508** METHOD: sqlite3_changeset_iter
10509**
10510** The pIter argument passed to this function may either be an iterator
10511** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
10512** created by [sqlite3changeset_start()]. In the latter case, the most recent
10513** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
10514** is not the case, this function returns [SQLITE_MISUSE].
10515**
10516** Arguments pOp, pnCol and pzTab may not be NULL. Upon return, three
10517** outputs are set through these pointers:
10518**
10519** *pOp is set to one of [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE],
10520** depending on the type of change that the iterator currently points to;
10521**
10522** *pnCol is set to the number of columns in the table affected by the change; and
10523**
10524** *pzTab is set to point to a nul-terminated utf-8 encoded string containing
10525** the name of the table affected by the current change. The buffer remains
10526** valid until either sqlite3changeset_next() is called on the iterator
10527** or until the conflict-handler function returns.
10528**
10529** If pbIndirect is not NULL, then *pbIndirect is set to true (1) if the change
10530** is an indirect change, or false (0) otherwise. See the documentation for
10531** [sqlite3session_indirect()] for a description of direct and indirect
10532** changes.
10533**
10534** If no error occurs, SQLITE_OK is returned. If an error does occur, an
10535** SQLite error code is returned. The values of the output variables may not
10536** be trusted in this case.
10537*/
10538
10539/*
10540** CAPI3REF: Obtain The Primary Key Definition Of A Table
10541** METHOD: sqlite3_changeset_iter
10542**
10543** For each modified table, a changeset includes the following:
10544**
10545** <ul>
10546** <li> The number of columns in the table, and
10547** <li> Which of those columns make up the tables PRIMARY KEY.
10548** </ul>
10549**
10550** This function is used to find which columns comprise the PRIMARY KEY of
10551** the table modified by the change that iterator pIter currently points to.
10552** If successful, *pabPK is set to point to an array of nCol entries, where
10553** nCol is the number of columns in the table. Elements of *pabPK are set to
10554** 0x01 if the corresponding column is part of the tables primary key, or
10555** 0x00 if it is not.
10556**
10557** If argument pnCol is not NULL, then *pnCol is set to the number of columns
10558** in the table.
10559**
10560** If this function is called when the iterator does not point to a valid
10561** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
10562** SQLITE_OK is returned and the output variables populated as described
10563** above.
10564*/
10565
10566/*
10567** CAPI3REF: Obtain old.* Values From A Changeset Iterator
10568** METHOD: sqlite3_changeset_iter
10569**
10570** The pIter argument passed to this function may either be an iterator
10571** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
10572** created by [sqlite3changeset_start()]. In the latter case, the most recent
10573** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
10574** Furthermore, it may only be called if the type of change that the iterator
10575** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
10576** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
10577**
10578** Argument iVal must be greater than or equal to 0, and less than the number
10579** of columns in the table affected by the current change. Otherwise,
10580** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
10581**
10582** If successful, this function sets *ppValue to point to a protected
10583** sqlite3_value object containing the iVal'th value from the vector of
10584** original row values stored as part of the UPDATE or DELETE change and
10585** returns SQLITE_OK. The name of the function comes from the fact that this
10586** is similar to the "old.*" columns available to update or delete triggers.
10587**
10588** If some other error occurs (e.g. an OOM condition), an SQLite error code
10589** is returned and *ppValue is set to NULL.
10590*/
10591
10592/*
10593** CAPI3REF: Obtain new.* Values From A Changeset Iterator
10594** METHOD: sqlite3_changeset_iter
10595**
10596** The pIter argument passed to this function may either be an iterator
10597** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
10598** created by [sqlite3changeset_start()]. In the latter case, the most recent
10599** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
10600** Furthermore, it may only be called if the type of change that the iterator
10601** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
10602** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
10603**
10604** Argument iVal must be greater than or equal to 0, and less than the number
10605** of columns in the table affected by the current change. Otherwise,
10606** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
10607**
10608** If successful, this function sets *ppValue to point to a protected
10609** sqlite3_value object containing the iVal'th value from the vector of
10610** new row values stored as part of the UPDATE or INSERT change and
10611** returns SQLITE_OK. If the change is an UPDATE and does not include
10612** a new value for the requested column, *ppValue is set to NULL and
10613** SQLITE_OK returned. The name of the function comes from the fact that
10614** this is similar to the "new.*" columns available to update or delete
10615** triggers.
10616**
10617** If some other error occurs (e.g. an OOM condition), an SQLite error code
10618** is returned and *ppValue is set to NULL.
10619*/
10620
10621/*
10622** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
10623** METHOD: sqlite3_changeset_iter
10624**
10625** This function should only be used with iterator objects passed to a
10626** conflict-handler callback by [sqlite3changeset_apply()] with either
10627** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
10628** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
10629** is set to NULL.
10630**
10631** Argument iVal must be greater than or equal to 0, and less than the number
10632** of columns in the table affected by the current change. Otherwise,
10633** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
10634**
10635** If successful, this function sets *ppValue to point to a protected
10636** sqlite3_value object containing the iVal'th value from the
10637** "conflicting row" associated with the current conflict-handler callback
10638** and returns SQLITE_OK.
10639**
10640** If some other error occurs (e.g. an OOM condition), an SQLite error code
10641** is returned and *ppValue is set to NULL.
10642*/
10643
10644/*
10645** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
10646** METHOD: sqlite3_changeset_iter
10647**
10648** This function may only be called with an iterator passed to an
10649** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
10650** it sets the output variable to the total number of known foreign key
10651** violations in the destination database and returns SQLITE_OK.
10652**
10653** In all other cases this function returns SQLITE_MISUSE.
10654*/
10655
10656
10657/*
10658** CAPI3REF: Finalize A Changeset Iterator
10659** METHOD: sqlite3_changeset_iter
10660**
10661** This function is used to finalize an iterator allocated with
10662** [sqlite3changeset_start()].
10663**
10664** This function should only be called on iterators created using the
10665** [sqlite3changeset_start()] function. If an application calls this
10666** function with an iterator passed to a conflict-handler by
10667** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
10668** call has no effect.
10669**
10670** If an error was encountered within a call to an sqlite3changeset_xxx()
10671** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an
10672** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
10673** to that error is returned by this function. Otherwise, SQLITE_OK is
10674** returned. This is to allow the following pattern (pseudo-code):
10675**
10676** <pre>
10677** sqlite3changeset_start();
10678** while( SQLITE_ROW==sqlite3changeset_next() ){
10679** // Do something with change.
10680** }
10681** rc = sqlite3changeset_finalize();
10682** if( rc!=SQLITE_OK ){
10683** // An error has occurred
10684** }
10685** </pre>
10686*/
10687
10688/*
10689** CAPI3REF: Invert A Changeset
10690**
10691** This function is used to "invert" a changeset object. Applying an inverted
10692** changeset to a database reverses the effects of applying the uninverted
10693** changeset. Specifically:
10694**
10695** <ul>
10696** <li> Each DELETE change is changed to an INSERT, and
10697** <li> Each INSERT change is changed to a DELETE, and
10698** <li> For each UPDATE change, the old.* and new.* values are exchanged.
10699** </ul>
10700**
10701** This function does not change the order in which changes appear within
10702** the changeset. It merely reverses the sense of each individual change.
10703**
10704** If successful, a pointer to a buffer containing the inverted changeset
10705** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
10706** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
10707** zeroed and an SQLite error code returned.
10708**
10709** It is the responsibility of the caller to eventually call sqlite3_free()
10710** on the *ppOut pointer to free the buffer allocation following a successful
10711** call to this function.
10712**
10713** WARNING/TODO: This function currently assumes that the input is a valid
10714** changeset. If it is not, the results are undefined.
10715*/
10716
10717/*
10718** CAPI3REF: Concatenate Two Changeset Objects
10719**
10720** This function is used to concatenate two changesets, A and B, into a
10721** single changeset. The result is a changeset equivalent to applying
10722** changeset A followed by changeset B.
10723**
10724** This function combines the two input changesets using an
10725** sqlite3_changegroup object. Calling it produces similar results as the
10726** following code fragment:
10727**
10728** <pre>
10729** sqlite3_changegroup *pGrp;
10730** rc = sqlite3_changegroup_new(&pGrp);
10731** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
10732** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
10733** if( rc==SQLITE_OK ){
10734** rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
10735** }else{
10736** *ppOut = 0;
10737** *pnOut = 0;
10738** }
10739** </pre>
10740**
10741** Refer to the sqlite3_changegroup documentation below for details.
10742*/
10743
10744
10745/*
10746** CAPI3REF: Changegroup Handle
10747**
10748** A changegroup is an object used to combine two or more
10749** [changesets] or [patchsets]
10750*/
10751typedef struct sqlite3_changegroup sqlite3_changegroup;
10752
10753/*
10754** CAPI3REF: Create A New Changegroup Object
10755** CONSTRUCTOR: sqlite3_changegroup
10756**
10757** An sqlite3_changegroup object is used to combine two or more changesets
10758** (or patchsets) into a single changeset (or patchset). A single changegroup
10759** object may combine changesets or patchsets, but not both. The output is
10760** always in the same format as the input.
10761**
10762** If successful, this function returns SQLITE_OK and populates (*pp) with
10763** a pointer to a new sqlite3_changegroup object before returning. The caller
10764** should eventually free the returned object using a call to
10765** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
10766** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
10767**
10768** The usual usage pattern for an sqlite3_changegroup object is as follows:
10769**
10770** <ul>
10771** <li> It is created using a call to sqlite3changegroup_new().
10772**
10773** <li> Zero or more changesets (or patchsets) are added to the object
10774** by calling sqlite3changegroup_add().
10775**
10776** <li> The result of combining all input changesets together is obtained
10777** by the application via a call to sqlite3changegroup_output().
10778**
10779** <li> The object is deleted using a call to sqlite3changegroup_delete().
10780** </ul>
10781**
10782** Any number of calls to add() and output() may be made between the calls to
10783** new() and delete(), and in any order.
10784**
10785** As well as the regular sqlite3changegroup_add() and
10786** sqlite3changegroup_output() functions, also available are the streaming
10787** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
10788*/
10789
10790/*
10791** CAPI3REF: Add A Changeset To A Changegroup
10792** METHOD: sqlite3_changegroup
10793**
10794** Add all changes within the changeset (or patchset) in buffer pData (size
10795** nData bytes) to the changegroup.
10796**
10797** If the buffer contains a patchset, then all prior calls to this function
10798** on the same changegroup object must also have specified patchsets. Or, if
10799** the buffer contains a changeset, so must have the earlier calls to this
10800** function. Otherwise, SQLITE_ERROR is returned and no changes are added
10801** to the changegroup.
10802**
10803** Rows within the changeset and changegroup are identified by the values in
10804** their PRIMARY KEY columns. A change in the changeset is considered to
10805** apply to the same row as a change already present in the changegroup if
10806** the two rows have the same primary key.
10807**
10808** Changes to rows that do not already appear in the changegroup are
10809** simply copied into it. Or, if both the new changeset and the changegroup
10810** contain changes that apply to a single row, the final contents of the
10811** changegroup depends on the type of each change, as follows:
10812**
10813** <table border=1 style="margin-left:8ex;margin-right:8ex">
10814** <tr><th style="white-space:pre">Existing Change </th>
10815** <th style="white-space:pre">New Change </th>
10816** <th>Output Change
10817** <tr><td>INSERT <td>INSERT <td>
10818** The new change is ignored. This case does not occur if the new
10819** changeset was recorded immediately after the changesets already
10820** added to the changegroup.
10821** <tr><td>INSERT <td>UPDATE <td>
10822** The INSERT change remains in the changegroup. The values in the
10823** INSERT change are modified as if the row was inserted by the
10824** existing change and then updated according to the new change.
10825** <tr><td>INSERT <td>DELETE <td>
10826** The existing INSERT is removed from the changegroup. The DELETE is
10827** not added.
10828** <tr><td>UPDATE <td>INSERT <td>
10829** The new change is ignored. This case does not occur if the new
10830** changeset was recorded immediately after the changesets already
10831** added to the changegroup.
10832** <tr><td>UPDATE <td>UPDATE <td>
10833** The existing UPDATE remains within the changegroup. It is amended
10834** so that the accompanying values are as if the row was updated once
10835** by the existing change and then again by the new change.
10836** <tr><td>UPDATE <td>DELETE <td>
10837** The existing UPDATE is replaced by the new DELETE within the
10838** changegroup.
10839** <tr><td>DELETE <td>INSERT <td>
10840** If one or more of the column values in the row inserted by the
10841** new change differ from those in the row deleted by the existing
10842** change, the existing DELETE is replaced by an UPDATE within the
10843** changegroup. Otherwise, if the inserted row is exactly the same
10844** as the deleted row, the existing DELETE is simply discarded.
10845** <tr><td>DELETE <td>UPDATE <td>
10846** The new change is ignored. This case does not occur if the new
10847** changeset was recorded immediately after the changesets already
10848** added to the changegroup.
10849** <tr><td>DELETE <td>DELETE <td>
10850** The new change is ignored. This case does not occur if the new
10851** changeset was recorded immediately after the changesets already
10852** added to the changegroup.
10853** </table>
10854**
10855** If the new changeset contains changes to a table that is already present
10856** in the changegroup, then the number of columns and the position of the
10857** primary key columns for the table must be consistent. If this is not the
10858** case, this function fails with SQLITE_SCHEMA. If the input changeset
10859** appears to be corrupt and the corruption is detected, SQLITE_CORRUPT is
10860** returned. Or, if an out-of-memory condition occurs during processing, this
10861** function returns SQLITE_NOMEM. In all cases, if an error occurs the state
10862** of the final contents of the changegroup is undefined.
10863**
10864** If no error occurs, SQLITE_OK is returned.
10865*/
10866
10867/*
10868** CAPI3REF: Obtain A Composite Changeset From A Changegroup
10869** METHOD: sqlite3_changegroup
10870**
10871** Obtain a buffer containing a changeset (or patchset) representing the
10872** current contents of the changegroup. If the inputs to the changegroup
10873** were themselves changesets, the output is a changeset. Or, if the
10874** inputs were patchsets, the output is also a patchset.
10875**
10876** As with the output of the sqlite3session_changeset() and
10877** sqlite3session_patchset() functions, all changes related to a single
10878** table are grouped together in the output of this function. Tables appear
10879** in the same order as for the very first changeset added to the changegroup.
10880** If the second or subsequent changesets added to the changegroup contain
10881** changes for tables that do not appear in the first changeset, they are
10882** appended onto the end of the output changeset, again in the order in
10883** which they are first encountered.
10884**
10885** If an error occurs, an SQLite error code is returned and the output
10886** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
10887** is returned and the output variables are set to the size of and a
10888** pointer to the output buffer, respectively. In this case it is the
10889** responsibility of the caller to eventually free the buffer using a
10890** call to sqlite3_free().
10891*/
10892
10893/*
10894** CAPI3REF: Delete A Changegroup Object
10895** DESTRUCTOR: sqlite3_changegroup
10896*/
10897
10898/*
10899** CAPI3REF: Apply A Changeset To A Database
10900**
10901** Apply a changeset or patchset to a database. These functions attempt to
10902** update the "main" database attached to handle db with the changes found in
10903** the changeset passed via the second and third arguments.
10904**
10905** The fourth argument (xFilter) passed to these functions is the "filter
10906** callback". If it is not NULL, then for each table affected by at least one
10907** change in the changeset, the filter callback is invoked with
10908** the table name as the second argument, and a copy of the context pointer
10909** passed as the sixth argument as the first. If the "filter callback"
10910** returns zero, then no attempt is made to apply any changes to the table.
10911** Otherwise, if the return value is non-zero or the xFilter argument to
10912** is NULL, all changes related to the table are attempted.
10913**
10914** For each table that is not excluded by the filter callback, this function
10915** tests that the target database contains a compatible table. A table is
10916** considered compatible if all of the following are true:
10917**
10918** <ul>
10919** <li> The table has the same name as the name recorded in the
10920** changeset, and
10921** <li> The table has at least as many columns as recorded in the
10922** changeset, and
10923** <li> The table has primary key columns in the same position as
10924** recorded in the changeset.
10925** </ul>
10926**
10927** If there is no compatible table, it is not an error, but none of the
10928** changes associated with the table are applied. A warning message is issued
10929** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
10930** one such warning is issued for each table in the changeset.
10931**
10932** For each change for which there is a compatible table, an attempt is made
10933** to modify the table contents according to the UPDATE, INSERT or DELETE
10934** change. If a change cannot be applied cleanly, the conflict handler
10935** function passed as the fifth argument to sqlite3changeset_apply() may be
10936** invoked. A description of exactly when the conflict handler is invoked for
10937** each type of change is below.
10938**
10939** Unlike the xFilter argument, xConflict may not be passed NULL. The results
10940** of passing anything other than a valid function pointer as the xConflict
10941** argument are undefined.
10942**
10943** Each time the conflict handler function is invoked, it must return one
10944** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or
10945** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
10946** if the second argument passed to the conflict handler is either
10947** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
10948** returns an illegal value, any changes already made are rolled back and
10949** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different
10950** actions are taken by sqlite3changeset_apply() depending on the value
10951** returned by each invocation of the conflict-handler function. Refer to
10952** the documentation for the three
10953** [SQLITE_CHANGESET_OMIT|available return values] for details.
10954**
10955** <dl>
10956** <dt>DELETE Changes<dd>
10957** For each DELETE change, the function checks if the target database
10958** contains a row with the same primary key value (or values) as the
10959** original row values stored in the changeset. If it does, and the values
10960** stored in all non-primary key columns also match the values stored in
10961** the changeset the row is deleted from the target database.
10962**
10963** If a row with matching primary key values is found, but one or more of
10964** the non-primary key fields contains a value different from the original
10965** row value stored in the changeset, the conflict-handler function is
10966** invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the
10967** database table has more columns than are recorded in the changeset,
10968** only the values of those non-primary key fields are compared against
10969** the current database contents - any trailing database table columns
10970** are ignored.
10971**
10972** If no row with matching primary key values is found in the database,
10973** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
10974** passed as the second argument.
10975**
10976** If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
10977** (which can only happen if a foreign key constraint is violated), the
10978** conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
10979** passed as the second argument. This includes the case where the DELETE
10980** operation is attempted because an earlier call to the conflict handler
10981** function returned [SQLITE_CHANGESET_REPLACE].
10982**
10983** <dt>INSERT Changes<dd>
10984** For each INSERT change, an attempt is made to insert the new row into
10985** the database. If the changeset row contains fewer fields than the
10986** database table, the trailing fields are populated with their default
10987** values.
10988**
10989** If the attempt to insert the row fails because the database already
10990** contains a row with the same primary key values, the conflict handler
10991** function is invoked with the second argument set to
10992** [SQLITE_CHANGESET_CONFLICT].
10993**
10994** If the attempt to insert the row fails because of some other constraint
10995** violation (e.g. NOT NULL or UNIQUE), the conflict handler function is
10996** invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
10997** This includes the case where the INSERT operation is re-attempted because
10998** an earlier call to the conflict handler function returned
10999** [SQLITE_CHANGESET_REPLACE].
11000**
11001** <dt>UPDATE Changes<dd>
11002** For each UPDATE change, the function checks if the target database
11003** contains a row with the same primary key value (or values) as the
11004** original row values stored in the changeset. If it does, and the values
11005** stored in all modified non-primary key columns also match the values
11006** stored in the changeset the row is updated within the target database.
11007**
11008** If a row with matching primary key values is found, but one or more of
11009** the modified non-primary key fields contains a value different from an
11010** original row value stored in the changeset, the conflict-handler function
11011** is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
11012** UPDATE changes only contain values for non-primary key fields that are
11013** to be modified, only those fields need to match the original values to
11014** avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
11015**
11016** If no row with matching primary key values is found in the database,
11017** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
11018** passed as the second argument.
11019**
11020** If the UPDATE operation is attempted, but SQLite returns
11021** SQLITE_CONSTRAINT, the conflict-handler function is invoked with
11022** [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
11023** This includes the case where the UPDATE operation is attempted after
11024** an earlier call to the conflict handler function returned
11025** [SQLITE_CHANGESET_REPLACE].
11026** </dl>
11027**
11028** It is safe to execute SQL statements, including those that write to the
11029** table that the callback related to, from within the xConflict callback.
11030** This can be used to further customize the application's conflict
11031** resolution strategy.
11032**
11033** All changes made by these functions are enclosed in a savepoint transaction.
11034** If any other error (aside from a constraint failure when attempting to
11035** write to the target database) occurs, then the savepoint transaction is
11036** rolled back, restoring the target database to its original state, and an
11037** SQLite error code returned.
11038**
11039** If the output parameters (ppRebase) and (pnRebase) are non-NULL and
11040** the input is a changeset (not a patchset), then sqlite3changeset_apply_v2()
11041** may set (*ppRebase) to point to a "rebase" that may be used with the
11042** sqlite3_rebaser APIs buffer before returning. In this case (*pnRebase)
11043** is set to the size of the buffer in bytes. It is the responsibility of the
11044** caller to eventually free any such buffer using sqlite3_free(). The buffer
11045** is only allocated and populated if one or more conflicts were encountered
11046** while applying the patchset. See comments surrounding the sqlite3_rebaser
11047** APIs for further details.
11048**
11049** The behavior of sqlite3changeset_apply_v2() and its streaming equivalent
11050** may be modified by passing a combination of
11051** [SQLITE_CHANGESETAPPLY_NOSAVEPOINT | supported flags] as the 9th parameter.
11052**
11053** Note that the sqlite3changeset_apply_v2() API is still <b>experimental</b>
11054** and therefore subject to change.
11055*/
11056
11057/*
11058** CAPI3REF: Flags for sqlite3changeset_apply_v2
11059**
11060** The following flags may passed via the 9th parameter to
11061** [sqlite3changeset_apply_v2] and [sqlite3changeset_apply_v2_strm]:
11062**
11063** <dl>
11064** <dt>SQLITE_CHANGESETAPPLY_NOSAVEPOINT <dd>
11065** Usually, the sessions module encloses all operations performed by
11066** a single call to apply_v2() or apply_v2_strm() in a [SAVEPOINT]. The
11067** SAVEPOINT is committed if the changeset or patchset is successfully
11068** applied, or rolled back if an error occurs. Specifying this flag
11069** causes the sessions module to omit this savepoint. In this case, if the
11070** caller has an open transaction or savepoint when apply_v2() is called,
11071** it may revert the partially applied changeset by rolling it back.
11072**
11073** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
11074** Invert the changeset before applying it. This is equivalent to inverting
11075** a changeset using sqlite3changeset_invert() before applying it. It is
11076** an error to specify this flag with a patchset.
11077*/
11078#define SQLITE_CHANGESETAPPLY_NOSAVEPOINT 0x0001
11079#define SQLITE_CHANGESETAPPLY_INVERT 0x0002
11080
11081/*
11082** CAPI3REF: Constants Passed To The Conflict Handler
11083**
11084** Values that may be passed as the second argument to a conflict-handler.
11085**
11086** <dl>
11087** <dt>SQLITE_CHANGESET_DATA<dd>
11088** The conflict handler is invoked with CHANGESET_DATA as the second argument
11089** when processing a DELETE or UPDATE change if a row with the required
11090** PRIMARY KEY fields is present in the database, but one or more other
11091** (non primary-key) fields modified by the update do not contain the
11092** expected "before" values.
11093**
11094** The conflicting row, in this case, is the database row with the matching
11095** primary key.
11096**
11097** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
11098** The conflict handler is invoked with CHANGESET_NOTFOUND as the second
11099** argument when processing a DELETE or UPDATE change if a row with the
11100** required PRIMARY KEY fields is not present in the database.
11101**
11102** There is no conflicting row in this case. The results of invoking the
11103** sqlite3changeset_conflict() API are undefined.
11104**
11105** <dt>SQLITE_CHANGESET_CONFLICT<dd>
11106** CHANGESET_CONFLICT is passed as the second argument to the conflict
11107** handler while processing an INSERT change if the operation would result
11108** in duplicate primary key values.
11109**
11110** The conflicting row in this case is the database row with the matching
11111** primary key.
11112**
11113** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
11114** If foreign key handling is enabled, and applying a changeset leaves the
11115** database in a state containing foreign key violations, the conflict
11116** handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
11117** exactly once before the changeset is committed. If the conflict handler
11118** returns CHANGESET_OMIT, the changes, including those that caused the
11119** foreign key constraint violation, are committed. Or, if it returns
11120** CHANGESET_ABORT, the changeset is rolled back.
11121**
11122** No current or conflicting row information is provided. The only function
11123** it is possible to call on the supplied sqlite3_changeset_iter handle
11124** is sqlite3changeset_fk_conflicts().
11125**
11126** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
11127** If any other constraint violation occurs while applying a change (i.e.
11128** a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is
11129** invoked with CHANGESET_CONSTRAINT as the second argument.
11130**
11131** There is no conflicting row in this case. The results of invoking the
11132** sqlite3changeset_conflict() API are undefined.
11133**
11134** </dl>
11135*/
11136#define SQLITE_CHANGESET_DATA 1
11137#define SQLITE_CHANGESET_NOTFOUND 2
11138#define SQLITE_CHANGESET_CONFLICT 3
11139#define SQLITE_CHANGESET_CONSTRAINT 4
11140#define SQLITE_CHANGESET_FOREIGN_KEY 5
11141
11142/*
11143** CAPI3REF: Constants Returned By The Conflict Handler
11144**
11145** A conflict handler callback must return one of the following three values.
11146**
11147** <dl>
11148** <dt>SQLITE_CHANGESET_OMIT<dd>
11149** If a conflict handler returns this value no special action is taken. The
11150** change that caused the conflict is not applied. The session module
11151** continues to the next change in the changeset.
11152**
11153** <dt>SQLITE_CHANGESET_REPLACE<dd>
11154** This value may only be returned if the second argument to the conflict
11155** handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
11156** is not the case, any changes applied so far are rolled back and the
11157** call to sqlite3changeset_apply() returns SQLITE_MISUSE.
11158**
11159** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
11160** handler, then the conflicting row is either updated or deleted, depending
11161** on the type of change.
11162**
11163** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
11164** handler, then the conflicting row is removed from the database and a
11165** second attempt to apply the change is made. If this second attempt fails,
11166** the original row is restored to the database before continuing.
11167**
11168** <dt>SQLITE_CHANGESET_ABORT<dd>
11169** If this value is returned, any changes applied so far are rolled back
11170** and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
11171** </dl>
11172*/
11173#define SQLITE_CHANGESET_OMIT 0
11174#define SQLITE_CHANGESET_REPLACE 1
11175#define SQLITE_CHANGESET_ABORT 2
11176
11177/*
11178** CAPI3REF: Rebasing changesets
11179** EXPERIMENTAL
11180**
11181** Suppose there is a site hosting a database in state S0. And that
11182** modifications are made that move that database to state S1 and a
11183** changeset recorded (the "local" changeset). Then, a changeset based
11184** on S0 is received from another site (the "remote" changeset) and
11185** applied to the database. The database is then in state
11186** (S1+"remote"), where the exact state depends on any conflict
11187** resolution decisions (OMIT or REPLACE) made while applying "remote".
11188** Rebasing a changeset is to update it to take those conflict
11189** resolution decisions into account, so that the same conflicts
11190** do not have to be resolved elsewhere in the network.
11191**
11192** For example, if both the local and remote changesets contain an
11193** INSERT of the same key on "CREATE TABLE t1(a PRIMARY KEY, b)":
11194**
11195** local: INSERT INTO t1 VALUES(1, 'v1');
11196** remote: INSERT INTO t1 VALUES(1, 'v2');
11197**
11198** and the conflict resolution is REPLACE, then the INSERT change is
11199** removed from the local changeset (it was overridden). Or, if the
11200** conflict resolution was "OMIT", then the local changeset is modified
11201** to instead contain:
11202**
11203** UPDATE t1 SET b = 'v2' WHERE a=1;
11204**
11205** Changes within the local changeset are rebased as follows:
11206**
11207** <dl>
11208** <dt>Local INSERT<dd>
11209** This may only conflict with a remote INSERT. If the conflict
11210** resolution was OMIT, then add an UPDATE change to the rebased
11211** changeset. Or, if the conflict resolution was REPLACE, add
11212** nothing to the rebased changeset.
11213**
11214** <dt>Local DELETE<dd>
11215** This may conflict with a remote UPDATE or DELETE. In both cases the
11216** only possible resolution is OMIT. If the remote operation was a
11217** DELETE, then add no change to the rebased changeset. If the remote
11218** operation was an UPDATE, then the old.* fields of change are updated
11219** to reflect the new.* values in the UPDATE.
11220**
11221** <dt>Local UPDATE<dd>
11222** This may conflict with a remote UPDATE or DELETE. If it conflicts
11223** with a DELETE, and the conflict resolution was OMIT, then the update
11224** is changed into an INSERT. Any undefined values in the new.* record
11225** from the update change are filled in using the old.* values from
11226** the conflicting DELETE. Or, if the conflict resolution was REPLACE,
11227** the UPDATE change is simply omitted from the rebased changeset.
11228**
11229** If conflict is with a remote UPDATE and the resolution is OMIT, then
11230** the old.* values are rebased using the new.* values in the remote
11231** change. Or, if the resolution is REPLACE, then the change is copied
11232** into the rebased changeset with updates to columns also updated by
11233** the conflicting remote UPDATE removed. If this means no columns would
11234** be updated, the change is omitted.
11235** </dl>
11236**
11237** A local change may be rebased against multiple remote changes
11238** simultaneously. If a single key is modified by multiple remote
11239** changesets, they are combined as follows before the local changeset
11240** is rebased:
11241**
11242** <ul>
11243** <li> If there has been one or more REPLACE resolutions on a
11244** key, it is rebased according to a REPLACE.
11245**
11246** <li> If there have been no REPLACE resolutions on a key, then
11247** the local changeset is rebased according to the most recent
11248** of the OMIT resolutions.
11249** </ul>
11250**
11251** Note that conflict resolutions from multiple remote changesets are
11252** combined on a per-field basis, not per-row. This means that in the
11253** case of multiple remote UPDATE operations, some fields of a single
11254** local change may be rebased for REPLACE while others are rebased for
11255** OMIT.
11256**
11257** In order to rebase a local changeset, the remote changeset must first
11258** be applied to the local database using sqlite3changeset_apply_v2() and
11259** the buffer of rebase information captured. Then:
11260**
11261** <ol>
11262** <li> An sqlite3_rebaser object is created by calling
11263** sqlite3rebaser_create().
11264** <li> The new object is configured with the rebase buffer obtained from
11265** sqlite3changeset_apply_v2() by calling sqlite3rebaser_configure().
11266** If the local changeset is to be rebased against multiple remote
11267** changesets, then sqlite3rebaser_configure() should be called
11268** multiple times, in the same order that the multiple
11269** sqlite3changeset_apply_v2() calls were made.
11270** <li> Each local changeset is rebased by calling sqlite3rebaser_rebase().
11271** <li> The sqlite3_rebaser object is deleted by calling
11272** sqlite3rebaser_delete().
11273** </ol>
11274*/
11275typedef struct sqlite3_rebaser sqlite3_rebaser;
11276
11277/*
11278** CAPI3REF: Create a changeset rebaser object.
11279** EXPERIMENTAL
11280**
11281** Allocate a new changeset rebaser object. If successful, set (*ppNew) to
11282** point to the new object and return SQLITE_OK. Otherwise, if an error
11283** occurs, return an SQLite error code (e.g. SQLITE_NOMEM) and set (*ppNew)
11284** to NULL.
11285*/
11286
11287/*
11288** CAPI3REF: Configure a changeset rebaser object.
11289** EXPERIMENTAL
11290**
11291** Configure the changeset rebaser object to rebase changesets according
11292** to the conflict resolutions described by buffer pRebase (size nRebase
11293** bytes), which must have been obtained from a previous call to
11294** sqlite3changeset_apply_v2().
11295*/
11296
11297/*
11298** CAPI3REF: Rebase a changeset
11299** EXPERIMENTAL
11300**
11301** Argument pIn must point to a buffer containing a changeset nIn bytes
11302** in size. This function allocates and populates a buffer with a copy
11303** of the changeset rebased according to the configuration of the
11304** rebaser object passed as the first argument. If successful, (*ppOut)
11305** is set to point to the new buffer containing the rebased changeset and
11306** (*pnOut) to its size in bytes and SQLITE_OK returned. It is the
11307** responsibility of the caller to eventually free the new buffer using
11308** sqlite3_free(). Otherwise, if an error occurs, (*ppOut) and (*pnOut)
11309** are set to zero and an SQLite error code returned.
11310*/
11311
11312/*
11313** CAPI3REF: Delete a changeset rebaser object.
11314** EXPERIMENTAL
11315**
11316** Delete the changeset rebaser object and all associated resources. There
11317** should be one call to this function for each successful invocation
11318** of sqlite3rebaser_create().
11319*/
11320
11321/*
11322** CAPI3REF: Streaming Versions of API functions.
11323**
11324** The six streaming API xxx_strm() functions serve similar purposes to the
11325** corresponding non-streaming API functions:
11326**
11327** <table border=1 style="margin-left:8ex;margin-right:8ex">
11328** <tr><th>Streaming function<th>Non-streaming equivalent</th>
11329** <tr><td>sqlite3changeset_apply_strm<td>[sqlite3changeset_apply]
11330** <tr><td>sqlite3changeset_apply_strm_v2<td>[sqlite3changeset_apply_v2]
11331** <tr><td>sqlite3changeset_concat_strm<td>[sqlite3changeset_concat]
11332** <tr><td>sqlite3changeset_invert_strm<td>[sqlite3changeset_invert]
11333** <tr><td>sqlite3changeset_start_strm<td>[sqlite3changeset_start]
11334** <tr><td>sqlite3session_changeset_strm<td>[sqlite3session_changeset]
11335** <tr><td>sqlite3session_patchset_strm<td>[sqlite3session_patchset]
11336** </table>
11337**
11338** Non-streaming functions that accept changesets (or patchsets) as input
11339** require that the entire changeset be stored in a single buffer in memory.
11340** Similarly, those that return a changeset or patchset do so by returning
11341** a pointer to a single large buffer allocated using sqlite3_malloc().
11342** Normally this is convenient. However, if an application running in a
11343** low-memory environment is required to handle very large changesets, the
11344** large contiguous memory allocations required can become onerous.
11345**
11346** In order to avoid this problem, instead of a single large buffer, input
11347** is passed to a streaming API functions by way of a callback function that
11348** the sessions module invokes to incrementally request input data as it is
11349** required. In all cases, a pair of API function parameters such as
11350**
11351** <pre>
11352** &nbsp; int nChangeset,
11353** &nbsp; void *pChangeset,
11354** </pre>
11355**
11356** Is replaced by:
11357**
11358** <pre>
11359** &nbsp; int (*xInput)(void *pIn, void *pData, int *pnData),
11360** &nbsp; void *pIn,
11361** </pre>
11362**
11363** Each time the xInput callback is invoked by the sessions module, the first
11364** argument passed is a copy of the supplied pIn context pointer. The second
11365** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no
11366** error occurs the xInput method should copy up to (*pnData) bytes of data
11367** into the buffer and set (*pnData) to the actual number of bytes copied
11368** before returning SQLITE_OK. If the input is completely exhausted, (*pnData)
11369** should be set to zero to indicate this. Or, if an error occurs, an SQLite
11370** error code should be returned. In all cases, if an xInput callback returns
11371** an error, all processing is abandoned and the streaming API function
11372** returns a copy of the error code to the caller.
11373**
11374** In the case of sqlite3changeset_start_strm(), the xInput callback may be
11375** invoked by the sessions module at any point during the lifetime of the
11376** iterator. If such an xInput callback returns an error, the iterator enters
11377** an error state, whereby all subsequent calls to iterator functions
11378** immediately fail with the same error code as returned by xInput.
11379**
11380** Similarly, streaming API functions that return changesets (or patchsets)
11381** return them in chunks by way of a callback function instead of via a
11382** pointer to a single large buffer. In this case, a pair of parameters such
11383** as:
11384**
11385** <pre>
11386** &nbsp; int *pnChangeset,
11387** &nbsp; void **ppChangeset,
11388** </pre>
11389**
11390** Is replaced by:
11391**
11392** <pre>
11393** &nbsp; int (*xOutput)(void *pOut, const void *pData, int nData),
11394** &nbsp; void *pOut
11395** </pre>
11396**
11397** The xOutput callback is invoked zero or more times to return data to
11398** the application. The first parameter passed to each call is a copy of the
11399** pOut pointer supplied by the application. The second parameter, pData,
11400** points to a buffer nData bytes in size containing the chunk of output
11401** data being returned. If the xOutput callback successfully processes the
11402** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
11403** it should return some other SQLite error code. In this case processing
11404** is immediately abandoned and the streaming API function returns a copy
11405** of the xOutput error code to the application.
11406**
11407** The sessions module never invokes an xOutput callback with the third
11408** parameter set to a value less than or equal to zero. Other than this,
11409** no guarantees are made as to the size of the chunks of data returned.
11410*/
11411
11412/*
11413** CAPI3REF: Configure global parameters
11414**
11415** The sqlite3session_config() interface is used to make global configuration
11416** changes to the sessions module in order to tune it to the specific needs
11417** of the application.
11418**
11419** The sqlite3session_config() interface is not threadsafe. If it is invoked
11420** while any other thread is inside any other sessions method then the
11421** results are undefined. Furthermore, if it is invoked after any sessions
11422** related objects have been created, the results are also undefined.
11423**
11424** The first argument to the sqlite3session_config() function must be one
11425** of the SQLITE_SESSION_CONFIG_XXX constants defined below. The
11426** interpretation of the (void*) value passed as the second parameter and
11427** the effect of calling this function depends on the value of the first
11428** parameter.
11429**
11430** <dl>
11431** <dt>SQLITE_SESSION_CONFIG_STRMSIZE<dd>
11432** By default, the sessions module streaming interfaces attempt to input
11433** and output data in approximately 1 KiB chunks. This operand may be used
11434** to set and query the value of this configuration setting. The pointer
11435** passed as the second argument must point to a value of type (int).
11436** If this value is greater than 0, it is used as the new streaming data
11437** chunk size for both input and output. Before returning, the (int) value
11438** pointed to by pArg is set to the final value of the streaming interface
11439** chunk size.
11440** </dl>
11441**
11442** This function returns SQLITE_OK if successful, or an SQLite error code
11443** otherwise.
11444*/
11445
11446/*
11447** CAPI3REF: Values for sqlite3session_config().
11448*/
11449#define SQLITE_SESSION_CONFIG_STRMSIZE 1
11450
11451/*
11452** Make sure we can call this stuff from C++.
11453*/
11454#ifdef __cplusplus
11455}
11456#endif
11457
11458#endif /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
11459
11460/******** End of sqlite3session.h *********/
11461/******** Begin file fts5.h *********/
11462/*
11463** 2014 May 31
11464**
11465** The author disclaims copyright to this source code. In place of
11466** a legal notice, here is a blessing:
11467**
11468** May you do good and not evil.
11469** May you find forgiveness for yourself and forgive others.
11470** May you share freely, never taking more than you give.
11471**
11472******************************************************************************
11473**
11474** Interfaces to extend FTS5. Using the interfaces defined in this file,
11475** FTS5 may be extended with:
11476**
11477** * custom tokenizers, and
11478** * custom auxiliary functions.
11479*/
11480
11481
11482#ifndef _FTS5_H
11483#define _FTS5_H
11484
11485
11486#ifdef __cplusplus
11487extern "C" {
11488#endif
11489
11490/*************************************************************************
11491** CUSTOM AUXILIARY FUNCTIONS
11492**
11493** Virtual table implementations may overload SQL functions by implementing
11494** the sqlite3_module.xFindFunction() method.
11495*/
11496
11497typedef struct Fts5ExtensionApi Fts5ExtensionApi;
11498typedef struct Fts5Context Fts5Context;
11499typedef struct Fts5PhraseIter Fts5PhraseIter;
11500
11501typedef void (*fts5_extension_function)(
11502 const Fts5ExtensionApi *pApi, /* API offered by current FTS version */
11503 Fts5Context *pFts, /* First arg to pass to pApi functions */
11504 sqlite3_context *pCtx, /* Context for returning result/error */
11505 int nVal, /* Number of values in apVal[] array */
11506 sqlite3_value **apVal /* Array of trailing arguments */
11507);
11508
11509struct Fts5PhraseIter {
11510 const unsigned char *a;
11511 const unsigned char *b;
11512};
11513
11514/*
11515** EXTENSION API FUNCTIONS
11516**
11517** xUserData(pFts):
11518** Return a copy of the context pointer the extension function was
11519** registered with.
11520**
11521** xColumnTotalSize(pFts, iCol, pnToken):
11522** If parameter iCol is less than zero, set output variable *pnToken
11523** to the total number of tokens in the FTS5 table. Or, if iCol is
11524** non-negative but less than the number of columns in the table, return
11525** the total number of tokens in column iCol, considering all rows in
11526** the FTS5 table.
11527**
11528** If parameter iCol is greater than or equal to the number of columns
11529** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
11530** an OOM condition or IO error), an appropriate SQLite error code is
11531** returned.
11532**
11533** xColumnCount(pFts):
11534** Return the number of columns in the table.
11535**
11536** xColumnSize(pFts, iCol, pnToken):
11537** If parameter iCol is less than zero, set output variable *pnToken
11538** to the total number of tokens in the current row. Or, if iCol is
11539** non-negative but less than the number of columns in the table, set
11540** *pnToken to the number of tokens in column iCol of the current row.
11541**
11542** If parameter iCol is greater than or equal to the number of columns
11543** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
11544** an OOM condition or IO error), an appropriate SQLite error code is
11545** returned.
11546**
11547** This function may be quite inefficient if used with an FTS5 table
11548** created with the "columnsize=0" option.
11549**
11550** xColumnText:
11551** This function attempts to retrieve the text of column iCol of the
11552** current document. If successful, (*pz) is set to point to a buffer
11553** containing the text in utf-8 encoding, (*pn) is set to the size in bytes
11554** (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
11555** if an error occurs, an SQLite error code is returned and the final values
11556** of (*pz) and (*pn) are undefined.
11557**
11558** xPhraseCount:
11559** Returns the number of phrases in the current query expression.
11560**
11561** xPhraseSize:
11562** Returns the number of tokens in phrase iPhrase of the query. Phrases
11563** are numbered starting from zero.
11564**
11565** xInstCount:
11566** Set *pnInst to the total number of occurrences of all phrases within
11567** the query within the current row. Return SQLITE_OK if successful, or
11568** an error code (i.e. SQLITE_NOMEM) if an error occurs.
11569**
11570** This API can be quite slow if used with an FTS5 table created with the
11571** "detail=none" or "detail=column" option. If the FTS5 table is created
11572** with either "detail=none" or "detail=column" and "content=" option
11573** (i.e. if it is a contentless table), then this API always returns 0.
11574**
11575** xInst:
11576** Query for the details of phrase match iIdx within the current row.
11577** Phrase matches are numbered starting from zero, so the iIdx argument
11578** should be greater than or equal to zero and smaller than the value
11579** output by xInstCount().
11580**
11581** Usually, output parameter *piPhrase is set to the phrase number, *piCol
11582** to the column in which it occurs and *piOff the token offset of the
11583** first token of the phrase. Returns SQLITE_OK if successful, or an error
11584** code (i.e. SQLITE_NOMEM) if an error occurs.
11585**
11586** This API can be quite slow if used with an FTS5 table created with the
11587** "detail=none" or "detail=column" option.
11588**
11589** xRowid:
11590** Returns the rowid of the current row.
11591**
11592** xTokenize:
11593** Tokenize text using the tokenizer belonging to the FTS5 table.
11594**
11595** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
11596** This API function is used to query the FTS table for phrase iPhrase
11597** of the current query. Specifically, a query equivalent to:
11598**
11599** ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
11600**
11601** with $p set to a phrase equivalent to the phrase iPhrase of the
11602** current query is executed. Any column filter that applies to
11603** phrase iPhrase of the current query is included in $p. For each
11604** row visited, the callback function passed as the fourth argument
11605** is invoked. The context and API objects passed to the callback
11606** function may be used to access the properties of each matched row.
11607** Invoking Api.xUserData() returns a copy of the pointer passed as
11608** the third argument to pUserData.
11609**
11610** If the callback function returns any value other than SQLITE_OK, the
11611** query is abandoned and the xQueryPhrase function returns immediately.
11612** If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
11613** Otherwise, the error code is propagated upwards.
11614**
11615** If the query runs to completion without incident, SQLITE_OK is returned.
11616** Or, if some error occurs before the query completes or is aborted by
11617** the callback, an SQLite error code is returned.
11618**
11619**
11620** xSetAuxdata(pFts5, pAux, xDelete)
11621**
11622** Save the pointer passed as the second argument as the extension function's
11623** "auxiliary data". The pointer may then be retrieved by the current or any
11624** future invocation of the same fts5 extension function made as part of
11625** the same MATCH query using the xGetAuxdata() API.
11626**
11627** Each extension function is allocated a single auxiliary data slot for
11628** each FTS query (MATCH expression). If the extension function is invoked
11629** more than once for a single FTS query, then all invocations share a
11630** single auxiliary data context.
11631**
11632** If there is already an auxiliary data pointer when this function is
11633** invoked, then it is replaced by the new pointer. If an xDelete callback
11634** was specified along with the original pointer, it is invoked at this
11635** point.
11636**
11637** The xDelete callback, if one is specified, is also invoked on the
11638** auxiliary data pointer after the FTS5 query has finished.
11639**
11640** If an error (e.g. an OOM condition) occurs within this function,
11641** the auxiliary data is set to NULL and an error code returned. If the
11642** xDelete parameter was not NULL, it is invoked on the auxiliary data
11643** pointer before returning.
11644**
11645**
11646** xGetAuxdata(pFts5, bClear)
11647**
11648** Returns the current auxiliary data pointer for the fts5 extension
11649** function. See the xSetAuxdata() method for details.
11650**
11651** If the bClear argument is non-zero, then the auxiliary data is cleared
11652** (set to NULL) before this function returns. In this case the xDelete,
11653** if any, is not invoked.
11654**
11655**
11656** xRowCount(pFts5, pnRow)
11657**
11658** This function is used to retrieve the total number of rows in the table.
11659** In other words, the same value that would be returned by:
11660**
11661** SELECT count(*) FROM ftstable;
11662**
11663** xPhraseFirst()
11664** This function is used, along with type Fts5PhraseIter and the xPhraseNext
11665** method, to iterate through all instances of a single query phrase within
11666** the current row. This is the same information as is accessible via the
11667** xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
11668** to use, this API may be faster under some circumstances. To iterate
11669** through instances of phrase iPhrase, use the following code:
11670**
11671** Fts5PhraseIter iter;
11672** int iCol, iOff;
11673** for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
11674** iCol>=0;
11675** pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
11676** ){
11677** // An instance of phrase iPhrase at offset iOff of column iCol
11678** }
11679**
11680** The Fts5PhraseIter structure is defined above. Applications should not
11681** modify this structure directly - it should only be used as shown above
11682** with the xPhraseFirst() and xPhraseNext() API methods (and by
11683** xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
11684**
11685** This API can be quite slow if used with an FTS5 table created with the
11686** "detail=none" or "detail=column" option. If the FTS5 table is created
11687** with either "detail=none" or "detail=column" and "content=" option
11688** (i.e. if it is a contentless table), then this API always iterates
11689** through an empty set (all calls to xPhraseFirst() set iCol to -1).
11690**
11691** xPhraseNext()
11692** See xPhraseFirst above.
11693**
11694** xPhraseFirstColumn()
11695** This function and xPhraseNextColumn() are similar to the xPhraseFirst()
11696** and xPhraseNext() APIs described above. The difference is that instead
11697** of iterating through all instances of a phrase in the current row, these
11698** APIs are used to iterate through the set of columns in the current row
11699** that contain one or more instances of a specified phrase. For example:
11700**
11701** Fts5PhraseIter iter;
11702** int iCol;
11703** for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
11704** iCol>=0;
11705** pApi->xPhraseNextColumn(pFts, &iter, &iCol)
11706** ){
11707** // Column iCol contains at least one instance of phrase iPhrase
11708** }
11709**
11710** This API can be quite slow if used with an FTS5 table created with the
11711** "detail=none" option. If the FTS5 table is created with either
11712** "detail=none" "content=" option (i.e. if it is a contentless table),
11713** then this API always iterates through an empty set (all calls to
11714** xPhraseFirstColumn() set iCol to -1).
11715**
11716** The information accessed using this API and its companion
11717** xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
11718** (or xInst/xInstCount). The chief advantage of this API is that it is
11719** significantly more efficient than those alternatives when used with
11720** "detail=column" tables.
11721**
11722** xPhraseNextColumn()
11723** See xPhraseFirstColumn above.
11724*/
11725struct Fts5ExtensionApi {
11726 int iVersion; /* Currently always set to 3 */
11727
11728 void *(*xUserData)(Fts5Context*);
11729
11730 int (*xColumnCount)(Fts5Context*);
11731 int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
11732 int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
11733
11734 int (*xTokenize)(Fts5Context*,
11735 const char *pText, int nText, /* Text to tokenize */
11736 void *pCtx, /* Context passed to xToken() */
11737 int (*xToken)(void*, int, const char*, int, int, int) /* Callback */
11738 );
11739
11740 int (*xPhraseCount)(Fts5Context*);
11741 int (*xPhraseSize)(Fts5Context*, int iPhrase);
11742
11743 int (*xInstCount)(Fts5Context*, int *pnInst);
11744 int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
11745
11746 sqlite3_int64 (*xRowid)(Fts5Context*);
11747 int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
11748 int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
11749
11750 int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
11751 int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
11752 );
11753 int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
11754 void *(*xGetAuxdata)(Fts5Context*, int bClear);
11755
11756 int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
11757 void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
11758
11759 int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
11760 void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
11761};
11762
11763/*
11764** CUSTOM AUXILIARY FUNCTIONS
11765*************************************************************************/
11766
11767/*************************************************************************
11768** CUSTOM TOKENIZERS
11769**
11770** Applications may also register custom tokenizer types. A tokenizer
11771** is registered by providing fts5 with a populated instance of the
11772** following structure. All structure methods must be defined, setting
11773** any member of the fts5_tokenizer struct to NULL leads to undefined
11774** behaviour. The structure methods are expected to function as follows:
11775**
11776** xCreate:
11777** This function is used to allocate and initialize a tokenizer instance.
11778** A tokenizer instance is required to actually tokenize text.
11779**
11780** The first argument passed to this function is a copy of the (void*)
11781** pointer provided by the application when the fts5_tokenizer object
11782** was registered with FTS5 (the third argument to xCreateTokenizer()).
11783** The second and third arguments are an array of nul-terminated strings
11784** containing the tokenizer arguments, if any, specified following the
11785** tokenizer name as part of the CREATE VIRTUAL TABLE statement used
11786** to create the FTS5 table.
11787**
11788** The final argument is an output variable. If successful, (*ppOut)
11789** should be set to point to the new tokenizer handle and SQLITE_OK
11790** returned. If an error occurs, some value other than SQLITE_OK should
11791** be returned. In this case, fts5 assumes that the final value of *ppOut
11792** is undefined.
11793**
11794** xDelete:
11795** This function is invoked to delete a tokenizer handle previously
11796** allocated using xCreate(). Fts5 guarantees that this function will
11797** be invoked exactly once for each successful call to xCreate().
11798**
11799** xTokenize:
11800** This function is expected to tokenize the nText byte string indicated
11801** by argument pText. pText may or may not be nul-terminated. The first
11802** argument passed to this function is a pointer to an Fts5Tokenizer object
11803** returned by an earlier call to xCreate().
11804**
11805** The second argument indicates the reason that FTS5 is requesting
11806** tokenization of the supplied text. This is always one of the following
11807** four values:
11808**
11809** <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
11810** or removed from the FTS table. The tokenizer is being invoked to
11811** determine the set of tokens to add to (or delete from) the
11812** FTS index.
11813**
11814** <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
11815** against the FTS index. The tokenizer is being called to tokenize
11816** a bareword or quoted string specified as part of the query.
11817**
11818** <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
11819** FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
11820** followed by a "*" character, indicating that the last token
11821** returned by the tokenizer will be treated as a token prefix.
11822**
11823** <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
11824** satisfy an fts5_api.xTokenize() request made by an auxiliary
11825** function. Or an fts5_api.xColumnSize() request made by the same
11826** on a columnsize=0 database.
11827** </ul>
11828**
11829** For each token in the input string, the supplied callback xToken() must
11830** be invoked. The first argument to it should be a copy of the pointer
11831** passed as the second argument to xTokenize(). The third and fourth
11832** arguments are a pointer to a buffer containing the token text, and the
11833** size of the token in bytes. The 4th and 5th arguments are the byte offsets
11834** of the first byte of and first byte immediately following the text from
11835** which the token is derived within the input.
11836**
11837** The second argument passed to the xToken() callback ("tflags") should
11838** normally be set to 0. The exception is if the tokenizer supports
11839** synonyms. In this case see the discussion below for details.
11840**
11841** FTS5 assumes the xToken() callback is invoked for each token in the
11842** order that they occur within the input text.
11843**
11844** If an xToken() callback returns any value other than SQLITE_OK, then
11845** the tokenization should be abandoned and the xTokenize() method should
11846** immediately return a copy of the xToken() return value. Or, if the
11847** input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
11848** if an error occurs with the xTokenize() implementation itself, it
11849** may abandon the tokenization and return any error code other than
11850** SQLITE_OK or SQLITE_DONE.
11851**
11852** SYNONYM SUPPORT
11853**
11854** Custom tokenizers may also support synonyms. Consider a case in which a
11855** user wishes to query for a phrase such as "first place". Using the
11856** built-in tokenizers, the FTS5 query 'first + place' will match instances
11857** of "first place" within the document set, but not alternative forms
11858** such as "1st place". In some applications, it would be better to match
11859** all instances of "first place" or "1st place" regardless of which form
11860** the user specified in the MATCH query text.
11861**
11862** There are several ways to approach this in FTS5:
11863**
11864** <ol><li> By mapping all synonyms to a single token. In this case, using
11865** the above example, this means that the tokenizer returns the
11866** same token for inputs "first" and "1st". Say that token is in
11867** fact "first", so that when the user inserts the document "I won
11868** 1st place" entries are added to the index for tokens "i", "won",
11869** "first" and "place". If the user then queries for '1st + place',
11870** the tokenizer substitutes "first" for "1st" and the query works
11871** as expected.
11872**
11873** <li> By querying the index for all synonyms of each query term
11874** separately. In this case, when tokenizing query text, the
11875** tokenizer may provide multiple synonyms for a single term
11876** within the document. FTS5 then queries the index for each
11877** synonym individually. For example, faced with the query:
11878**
11879** <codeblock>
11880** ... MATCH 'first place'</codeblock>
11881**
11882** the tokenizer offers both "1st" and "first" as synonyms for the
11883** first token in the MATCH query and FTS5 effectively runs a query
11884** similar to:
11885**
11886** <codeblock>
11887** ... MATCH '(first OR 1st) place'</codeblock>
11888**
11889** except that, for the purposes of auxiliary functions, the query
11890** still appears to contain just two phrases - "(first OR 1st)"
11891** being treated as a single phrase.
11892**
11893** <li> By adding multiple synonyms for a single term to the FTS index.
11894** Using this method, when tokenizing document text, the tokenizer
11895** provides multiple synonyms for each token. So that when a
11896** document such as "I won first place" is tokenized, entries are
11897** added to the FTS index for "i", "won", "first", "1st" and
11898** "place".
11899**
11900** This way, even if the tokenizer does not provide synonyms
11901** when tokenizing query text (it should not - to do so would be
11902** inefficient), it doesn't matter if the user queries for
11903** 'first + place' or '1st + place', as there are entries in the
11904** FTS index corresponding to both forms of the first token.
11905** </ol>
11906**
11907** Whether it is parsing document or query text, any call to xToken that
11908** specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
11909** is considered to supply a synonym for the previous token. For example,
11910** when parsing the document "I won first place", a tokenizer that supports
11911** synonyms would call xToken() 5 times, as follows:
11912**
11913** <codeblock>
11914** xToken(pCtx, 0, "i", 1, 0, 1);
11915** xToken(pCtx, 0, "won", 3, 2, 5);
11916** xToken(pCtx, 0, "first", 5, 6, 11);
11917** xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3, 6, 11);
11918** xToken(pCtx, 0, "place", 5, 12, 17);
11919**</codeblock>
11920**
11921** It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
11922** xToken() is called. Multiple synonyms may be specified for a single token
11923** by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
11924** There is no limit to the number of synonyms that may be provided for a
11925** single token.
11926**
11927** In many cases, method (1) above is the best approach. It does not add
11928** extra data to the FTS index or require FTS5 to query for multiple terms,
11929** so it is efficient in terms of disk space and query speed. However, it
11930** does not support prefix queries very well. If, as suggested above, the
11931** token "first" is substituted for "1st" by the tokenizer, then the query:
11932**
11933** <codeblock>
11934** ... MATCH '1s*'</codeblock>
11935**
11936** will not match documents that contain the token "1st" (as the tokenizer
11937** will probably not map "1s" to any prefix of "first").
11938**
11939** For full prefix support, method (3) may be preferred. In this case,
11940** because the index contains entries for both "first" and "1st", prefix
11941** queries such as 'fi*' or '1s*' will match correctly. However, because
11942** extra entries are added to the FTS index, this method uses more space
11943** within the database.
11944**
11945** Method (2) offers a midpoint between (1) and (3). Using this method,
11946** a query such as '1s*' will match documents that contain the literal
11947** token "1st", but not "first" (assuming the tokenizer is not able to
11948** provide synonyms for prefixes). However, a non-prefix query like '1st'
11949** will match against "1st" and "first". This method does not require
11950** extra disk space, as no extra entries are added to the FTS index.
11951** On the other hand, it may require more CPU cycles to run MATCH queries,
11952** as separate queries of the FTS index are required for each synonym.
11953**
11954** When using methods (2) or (3), it is important that the tokenizer only
11955** provide synonyms when tokenizing document text (method (2)) or query
11956** text (method (3)), not both. Doing so will not cause any errors, but is
11957** inefficient.
11958*/
11959typedef struct Fts5Tokenizer Fts5Tokenizer;
11960typedef struct fts5_tokenizer fts5_tokenizer;
11961struct fts5_tokenizer {
11962 int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
11963 void (*xDelete)(Fts5Tokenizer*);
11964 int (*xTokenize)(Fts5Tokenizer*,
11965 void *pCtx,
11966 int flags, /* Mask of FTS5_TOKENIZE_* flags */
11967 const char *pText, int nText,
11968 int (*xToken)(
11969 void *pCtx, /* Copy of 2nd argument to xTokenize() */
11970 int tflags, /* Mask of FTS5_TOKEN_* flags */
11971 const char *pToken, /* Pointer to buffer containing token */
11972 int nToken, /* Size of token in bytes */
11973 int iStart, /* Byte offset of token within input text */
11974 int iEnd /* Byte offset of end of token within input text */
11975 )
11976 );
11977};
11978
11979/* Flags that may be passed as the third argument to xTokenize() */
11980#define FTS5_TOKENIZE_QUERY 0x0001
11981#define FTS5_TOKENIZE_PREFIX 0x0002
11982#define FTS5_TOKENIZE_DOCUMENT 0x0004
11983#define FTS5_TOKENIZE_AUX 0x0008
11984
11985/* Flags that may be passed by the tokenizer implementation back to FTS5
11986** as the third argument to the supplied xToken callback. */
11987#define FTS5_TOKEN_COLOCATED 0x0001 /* Same position as prev. token */
11988
11989/*
11990** END OF CUSTOM TOKENIZERS
11991*************************************************************************/
11992
11993/*************************************************************************
11994** FTS5 EXTENSION REGISTRATION API
11995*/
11996typedef struct fts5_api fts5_api;
11997struct fts5_api {
11998 int iVersion; /* Currently always set to 2 */
11999
12000 /* Create a new tokenizer */
12001 int (*xCreateTokenizer)(
12002 fts5_api *pApi,
12003 const char *zName,
12004 void *pContext,
12005 fts5_tokenizer *pTokenizer,
12006 void (*xDestroy)(void*)
12007 );
12008
12009 /* Find an existing tokenizer */
12010 int (*xFindTokenizer)(
12011 fts5_api *pApi,
12012 const char *zName,
12013 void **ppContext,
12014 fts5_tokenizer *pTokenizer
12015 );
12016
12017 /* Create a new auxiliary function */
12018 int (*xCreateFunction)(
12019 fts5_api *pApi,
12020 const char *zName,
12021 void *pContext,
12022 fts5_extension_function xFunction,
12023 void (*xDestroy)(void*)
12024 );
12025};
12026
12027/*
12028** END OF REGISTRATION API
12029*************************************************************************/
12030
12031#ifdef __cplusplus
12032} /* end of the 'extern "C"' block */
12033#endif
12034
12035#endif /* _FTS5_H */
12036
12037/******** End of fts5.h *********/
diff --git a/c/loadable-ext-sqlite3ext.h b/c/loadable-ext-sqlite3ext.h
new file mode 100644
index 0000000..0850553
--- /dev/null
+++ b/c/loadable-ext-sqlite3ext.h
@@ -0,0 +1,433 @@
1/*
2** 2006 June 7
3**
4** The author disclaims copyright to this source code. In place of
5** a legal notice, here is a blessing:
6**
7** May you do good and not evil.
8** May you find forgiveness for yourself and forgive others.
9** May you share freely, never taking more than you give.
10**
11*************************************************************************
12** This header file defines the SQLite interface for use by
13** shared libraries that want to be imported as extensions into
14** an SQLite instance. Shared libraries that intend to be loaded
15** as extensions by SQLite should #include this file instead of
16** sqlite3.h.
17*/
18#ifndef SQLITE3EXT_H
19#define SQLITE3EXT_H
20#include "loadable-ext-sqlite3.h"
21
22/*
23** The following structure holds pointers to all of the SQLite API
24** routines.
25**
26** WARNING: In order to maintain backwards compatibility, add new
27** interfaces to the end of this structure only. If you insert new
28** interfaces in the middle of this structure, then older different
29** versions of SQLite will not be able to load each other's shared
30** libraries!
31*/
32struct sqlite3_api_routines {
33 void * (*aggregate_context)(sqlite3_context*,int nBytes);
34 int (*aggregate_count)(sqlite3_context*);
35 int (*bind_blob)(sqlite3_stmt*,int,const void*,int n,void(*)(void*));
36 int (*bind_double)(sqlite3_stmt*,int,double);
37 int (*bind_int)(sqlite3_stmt*,int,int);
38 int (*bind_int64)(sqlite3_stmt*,int,sqlite_int64);
39 int (*bind_null)(sqlite3_stmt*,int);
40 int (*bind_parameter_count)(sqlite3_stmt*);
41 int (*bind_parameter_index)(sqlite3_stmt*,const char*zName);
42 const char * (*bind_parameter_name)(sqlite3_stmt*,int);
43 int (*bind_text)(sqlite3_stmt*,int,const char*,int n,void(*)(void*));
44 int (*bind_text16)(sqlite3_stmt*,int,const void*,int,void(*)(void*));
45 int (*bind_value)(sqlite3_stmt*,int,const sqlite3_value*);
46 int (*busy_handler)(sqlite3*,int(*)(void*,int),void*);
47 int (*busy_timeout)(sqlite3*,int ms);
48 int (*changes)(sqlite3*);
49 int (*close)(sqlite3*);
50 int (*collation_needed)(sqlite3*,void*,void(*)(void*,sqlite3*,
51 int eTextRep,const char*));
52 int (*collation_needed16)(sqlite3*,void*,void(*)(void*,sqlite3*,
53 int eTextRep,const void*));
54 const void * (*column_blob)(sqlite3_stmt*,int iCol);
55 int (*column_bytes)(sqlite3_stmt*,int iCol);
56 int (*column_bytes16)(sqlite3_stmt*,int iCol);
57 int (*column_count)(sqlite3_stmt*pStmt);
58 const char * (*column_database_name)(sqlite3_stmt*,int);
59 const void * (*column_database_name16)(sqlite3_stmt*,int);
60 const char * (*column_decltype)(sqlite3_stmt*,int i);
61 const void * (*column_decltype16)(sqlite3_stmt*,int);
62 double (*column_double)(sqlite3_stmt*,int iCol);
63 int (*column_int)(sqlite3_stmt*,int iCol);
64 sqlite_int64 (*column_int64)(sqlite3_stmt*,int iCol);
65 const char * (*column_name)(sqlite3_stmt*,int);
66 const void * (*column_name16)(sqlite3_stmt*,int);
67 const char * (*column_origin_name)(sqlite3_stmt*,int);
68 const void * (*column_origin_name16)(sqlite3_stmt*,int);
69 const char * (*column_table_name)(sqlite3_stmt*,int);
70 const void * (*column_table_name16)(sqlite3_stmt*,int);
71 const unsigned char * (*column_text)(sqlite3_stmt*,int iCol);
72 const void * (*column_text16)(sqlite3_stmt*,int iCol);
73 int (*column_type)(sqlite3_stmt*,int iCol);
74 sqlite3_value* (*column_value)(sqlite3_stmt*,int iCol);
75 void * (*commit_hook)(sqlite3*,int(*)(void*),void*);
76 int (*complete)(const char*sql);
77 int (*complete16)(const void*sql);
78 int (*create_collation)(sqlite3*,const char*,int,void*,
79 int(*)(void*,int,const void*,int,const void*));
80 int (*create_collation16)(sqlite3*,const void*,int,void*,
81 int(*)(void*,int,const void*,int,const void*));
82 int (*create_function)(sqlite3*,const char*,int,int,void*,
83 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
84 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
85 void (*xFinal)(sqlite3_context*));
86 int (*create_function16)(sqlite3*,const void*,int,int,void*,
87 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
88 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
89 void (*xFinal)(sqlite3_context*));
90 int (*create_module)(sqlite3*,const char*,const sqlite3_module*,void*);
91 int (*data_count)(sqlite3_stmt*pStmt);
92 sqlite3 * (*db_handle)(sqlite3_stmt*);
93 int (*declare_vtab)(sqlite3*,const char*);
94 int (*enable_shared_cache)(int);
95 int (*errcode)(sqlite3*db);
96 const char * (*errmsg)(sqlite3*);
97 const void * (*errmsg16)(sqlite3*);
98 int (*exec)(sqlite3*,const char*,sqlite3_callback,void*,char**);
99 int (*expired)(sqlite3_stmt*);
100 int (*finalize)(sqlite3_stmt*pStmt);
101 void (*free)(void*);
102 void (*free_table)(char**result);
103 int (*get_autocommit)(sqlite3*);
104 void * (*get_auxdata)(sqlite3_context*,int);
105 int (*get_table)(sqlite3*,const char*,char***,int*,int*,char**);
106 int (*global_recover)(void);
107 void (*interruptx)(sqlite3*);
108 sqlite_int64 (*last_insert_rowid)(sqlite3*);
109 const char * (*libversion)(void);
110 int (*libversion_number)(void);
111 void *(*malloc)(int);
112 char * (*mprintf)(const char*,...);
113 int (*open)(const char*,sqlite3**);
114 int (*open16)(const void*,sqlite3**);
115 int (*prepare)(sqlite3*,const char*,int,sqlite3_stmt**,const char**);
116 int (*prepare16)(sqlite3*,const void*,int,sqlite3_stmt**,const void**);
117 void * (*profile)(sqlite3*,void(*)(void*,const char*,sqlite_uint64),void*);
118 void (*progress_handler)(sqlite3*,int,int(*)(void*),void*);
119 void *(*realloc)(void*,int);
120 int (*reset)(sqlite3_stmt*pStmt);
121 void (*result_blob)(sqlite3_context*,const void*,int,void(*)(void*));
122 void (*result_double)(sqlite3_context*,double);
123 void (*result_error)(sqlite3_context*,const char*,int);
124 void (*result_error16)(sqlite3_context*,const void*,int);
125 void (*result_int)(sqlite3_context*,int);
126 void (*result_int64)(sqlite3_context*,sqlite_int64);
127 void (*result_null)(sqlite3_context*);
128 void (*result_text)(sqlite3_context*,const char*,int,void(*)(void*));
129 void (*result_text16)(sqlite3_context*,const void*,int,void(*)(void*));
130 void (*result_text16be)(sqlite3_context*,const void*,int,void(*)(void*));
131 void (*result_text16le)(sqlite3_context*,const void*,int,void(*)(void*));
132 void (*result_value)(sqlite3_context*,sqlite3_value*);
133 void * (*rollback_hook)(sqlite3*,void(*)(void*),void*);
134 int (*set_authorizer)(sqlite3*,int(*)(void*,int,const char*,const char*,
135 const char*,const char*),void*);
136 void (*set_auxdata)(sqlite3_context*,int,void*,void (*)(void*));
137 char * (*xsnprintf)(int,char*,const char*,...);
138 int (*step)(sqlite3_stmt*);
139 int (*table_column_metadata)(sqlite3*,const char*,const char*,const char*,
140 char const**,char const**,int*,int*,int*);
141 void (*thread_cleanup)(void);
142 int (*total_changes)(sqlite3*);
143 void * (*trace)(sqlite3*,void(*xTrace)(void*,const char*),void*);
144 int (*transfer_bindings)(sqlite3_stmt*,sqlite3_stmt*);
145 void * (*update_hook)(sqlite3*,void(*)(void*,int ,char const*,char const*,
146 sqlite_int64),void*);
147 void * (*user_data)(sqlite3_context*);
148 const void * (*value_blob)(sqlite3_value*);
149 int (*value_bytes)(sqlite3_value*);
150 int (*value_bytes16)(sqlite3_value*);
151 double (*value_double)(sqlite3_value*);
152 int (*value_int)(sqlite3_value*);
153 sqlite_int64 (*value_int64)(sqlite3_value*);
154 int (*value_numeric_type)(sqlite3_value*);
155 const unsigned char * (*value_text)(sqlite3_value*);
156 const void * (*value_text16)(sqlite3_value*);
157 const void * (*value_text16be)(sqlite3_value*);
158 const void * (*value_text16le)(sqlite3_value*);
159 int (*value_type)(sqlite3_value*);
160 char *(*vmprintf)(const char*,va_list);
161 /* Added ??? */
162 int (*overload_function)(sqlite3*, const char *zFuncName, int nArg);
163 /* Added by 3.3.13 */
164 int (*prepare_v2)(sqlite3*,const char*,int,sqlite3_stmt**,const char**);
165 int (*prepare16_v2)(sqlite3*,const void*,int,sqlite3_stmt**,const void**);
166 int (*clear_bindings)(sqlite3_stmt*);
167 /* Added by 3.4.1 */
168 int (*create_module_v2)(sqlite3*,const char*,const sqlite3_module*,void*,
169 void (*xDestroy)(void *));
170 /* Added by 3.5.0 */
171 int (*bind_zeroblob)(sqlite3_stmt*,int,int);
172 int (*blob_bytes)(sqlite3_blob*);
173 int (*blob_close)(sqlite3_blob*);
174 int (*blob_open)(sqlite3*,const char*,const char*,const char*,sqlite3_int64,
175 int,sqlite3_blob**);
176 int (*blob_read)(sqlite3_blob*,void*,int,int);
177 int (*blob_write)(sqlite3_blob*,const void*,int,int);
178 int (*create_collation_v2)(sqlite3*,const char*,int,void*,
179 int(*)(void*,int,const void*,int,const void*),
180 void(*)(void*));
181 int (*file_control)(sqlite3*,const char*,int,void*);
182 sqlite3_int64 (*memory_highwater)(int);
183 sqlite3_int64 (*memory_used)(void);
184 sqlite3_mutex *(*mutex_alloc)(int);
185 void (*mutex_enter)(sqlite3_mutex*);
186 void (*mutex_free)(sqlite3_mutex*);
187 void (*mutex_leave)(sqlite3_mutex*);
188 int (*mutex_try)(sqlite3_mutex*);
189 int (*open_v2)(const char*,sqlite3**,int,const char*);
190 int (*release_memory)(int);
191 void (*result_error_nomem)(sqlite3_context*);
192 void (*result_error_toobig)(sqlite3_context*);
193 int (*sleep)(int);
194 void (*soft_heap_limit)(int);
195 sqlite3_vfs *(*vfs_find)(const char*);
196 int (*vfs_register)(sqlite3_vfs*,int);
197 int (*vfs_unregister)(sqlite3_vfs*);
198 int (*xthreadsafe)(void);
199 void (*result_zeroblob)(sqlite3_context*,int);
200 void (*result_error_code)(sqlite3_context*,int);
201 int (*test_control)(int, ...);
202 void (*randomness)(int,void*);
203 sqlite3 *(*context_db_handle)(sqlite3_context*);
204 int (*extended_result_codes)(sqlite3*,int);
205 int (*limit)(sqlite3*,int,int);
206 sqlite3_stmt *(*next_stmt)(sqlite3*,sqlite3_stmt*);
207 const char *(*sql)(sqlite3_stmt*);
208 int (*status)(int,int*,int*,int);
209 int (*backup_finish)(sqlite3_backup*);
210 sqlite3_backup *(*backup_init)(sqlite3*,const char*,sqlite3*,const char*);
211 int (*backup_pagecount)(sqlite3_backup*);
212 int (*backup_remaining)(sqlite3_backup*);
213 int (*backup_step)(sqlite3_backup*,int);
214 const char *(*compileoption_get)(int);
215 int (*compileoption_used)(const char*);
216 int (*create_function_v2)(sqlite3*,const char*,int,int,void*,
217 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
218 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
219 void (*xFinal)(sqlite3_context*),
220 void(*xDestroy)(void*));
221 int (*db_config)(sqlite3*,int,...);
222 sqlite3_mutex *(*db_mutex)(sqlite3*);
223 int (*db_status)(sqlite3*,int,int*,int*,int);
224 int (*extended_errcode)(sqlite3*);
225 void (*log)(int,const char*,...);
226 sqlite3_int64 (*soft_heap_limit64)(sqlite3_int64);
227 const char *(*sourceid)(void);
228 int (*stmt_status)(sqlite3_stmt*,int,int);
229 int (*strnicmp)(const char*,const char*,int);
230 int (*unlock_notify)(sqlite3*,void(*)(void**,int),void*);
231 int (*wal_autocheckpoint)(sqlite3*,int);
232 int (*wal_checkpoint)(sqlite3*,const char*);
233 void *(*wal_hook)(sqlite3*,int(*)(void*,sqlite3*,const char*,int),void*);
234 int (*blob_reopen)(sqlite3_blob*,sqlite3_int64);
235 int (*vtab_config)(sqlite3*,int op,...);
236 int (*vtab_on_conflict)(sqlite3*);
237 /* Version 3.7.16 and later */
238 int (*close_v2)(sqlite3*);
239 const char *(*db_filename)(sqlite3*,const char*);
240 int (*db_readonly)(sqlite3*,const char*);
241 int (*db_release_memory)(sqlite3*);
242 const char *(*errstr)(int);
243 int (*stmt_busy)(sqlite3_stmt*);
244 int (*stmt_readonly)(sqlite3_stmt*);
245 int (*stricmp)(const char*,const char*);
246 int (*uri_boolean)(const char*,const char*,int);
247 sqlite3_int64 (*uri_int64)(const char*,const char*,sqlite3_int64);
248 const char *(*uri_parameter)(const char*,const char*);
249 char *(*xvsnprintf)(int,char*,const char*,va_list);
250 int (*wal_checkpoint_v2)(sqlite3*,const char*,int,int*,int*);
251 /* Version 3.8.7 and later */
252 int (*auto_extension)(void(*)(void));
253 int (*bind_blob64)(sqlite3_stmt*,int,const void*,sqlite3_uint64,
254 void(*)(void*));
255 int (*bind_text64)(sqlite3_stmt*,int,const char*,sqlite3_uint64,
256 void(*)(void*),unsigned char);
257 int (*cancel_auto_extension)(void(*)(void));
258 int (*load_extension)(sqlite3*,const char*,const char*,char**);
259 void *(*malloc64)(sqlite3_uint64);
260 sqlite3_uint64 (*msize)(void*);
261 void *(*realloc64)(void*,sqlite3_uint64);
262 void (*reset_auto_extension)(void);
263 void (*result_blob64)(sqlite3_context*,const void*,sqlite3_uint64,
264 void(*)(void*));
265 void (*result_text64)(sqlite3_context*,const char*,sqlite3_uint64,
266 void(*)(void*), unsigned char);
267 int (*strglob)(const char*,const char*);
268 /* Version 3.8.11 and later */
269 sqlite3_value *(*value_dup)(const sqlite3_value*);
270 void (*value_free)(sqlite3_value*);
271 int (*result_zeroblob64)(sqlite3_context*,sqlite3_uint64);
272 int (*bind_zeroblob64)(sqlite3_stmt*, int, sqlite3_uint64);
273 /* Version 3.9.0 and later */
274 unsigned int (*value_subtype)(sqlite3_value*);
275 void (*result_subtype)(sqlite3_context*,unsigned int);
276 /* Version 3.10.0 and later */
277 int (*status64)(int,sqlite3_int64*,sqlite3_int64*,int);
278 int (*strlike)(const char*,const char*,unsigned int);
279 int (*db_cacheflush)(sqlite3*);
280 /* Version 3.12.0 and later */
281 int (*system_errno)(sqlite3*);
282 /* Version 3.14.0 and later */
283 int (*trace_v2)(sqlite3*,unsigned,int(*)(unsigned,void*,void*,void*),void*);
284 char *(*expanded_sql)(sqlite3_stmt*);
285 /* Version 3.18.0 and later */
286 void (*set_last_insert_rowid)(sqlite3*,sqlite3_int64);
287 /* Version 3.20.0 and later */
288 int (*prepare_v3)(sqlite3*,const char*,int,unsigned int,
289 sqlite3_stmt**,const char**);
290 int (*prepare16_v3)(sqlite3*,const void*,int,unsigned int,
291 sqlite3_stmt**,const void**);
292 int (*bind_pointer)(sqlite3_stmt*,int,void*,const char*,void(*)(void*));
293 void (*result_pointer)(sqlite3_context*,void*,const char*,void(*)(void*));
294 void *(*value_pointer)(sqlite3_value*,const char*);
295 int (*vtab_nochange)(sqlite3_context*);
296 int (*value_nochange)(sqlite3_value*);
297 const char *(*vtab_collation)(sqlite3_index_info*,int);
298 /* Version 3.24.0 and later */
299 int (*keyword_count)(void);
300 int (*keyword_name)(int,const char**,int*);
301 int (*keyword_check)(const char*,int);
302 sqlite3_str *(*str_new)(sqlite3*);
303 char *(*str_finish)(sqlite3_str*);
304 void (*str_appendf)(sqlite3_str*, const char *zFormat, ...);
305 void (*str_vappendf)(sqlite3_str*, const char *zFormat, va_list);
306 void (*str_append)(sqlite3_str*, const char *zIn, int N);
307 void (*str_appendall)(sqlite3_str*, const char *zIn);
308 void (*str_appendchar)(sqlite3_str*, int N, char C);
309 void (*str_reset)(sqlite3_str*);
310 int (*str_errcode)(sqlite3_str*);
311 int (*str_length)(sqlite3_str*);
312 char *(*str_value)(sqlite3_str*);
313 /* Version 3.25.0 and later */
314 int (*create_window_function)(sqlite3*,const char*,int,int,void*,
315 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
316 void (*xFinal)(sqlite3_context*),
317 void (*xValue)(sqlite3_context*),
318 void (*xInv)(sqlite3_context*,int,sqlite3_value**),
319 void(*xDestroy)(void*));
320 /* Version 3.26.0 and later */
321 const char *(*normalized_sql)(sqlite3_stmt*);
322 /* Version 3.28.0 and later */
323 int (*stmt_isexplain)(sqlite3_stmt*);
324 int (*value_frombind)(sqlite3_value*);
325 /* Version 3.30.0 and later */
326 int (*drop_modules)(sqlite3*,const char**);
327 /* Version 3.31.0 and later */
328 sqlite3_int64 (*hard_heap_limit64)(sqlite3_int64);
329 const char *(*uri_key)(const char*,int);
330 const char *(*filename_database)(const char*);
331 const char *(*filename_journal)(const char*);
332 const char *(*filename_wal)(const char*);
333 /* Version 3.32.0 and later */
334 char *(*create_filename)(const char*,const char*,const char*,
335 int,const char**);
336 void (*free_filename)(char*);
337 sqlite3_file *(*database_file_object)(const char*);
338 /* Version 3.34.0 and later */
339 int (*txn_state)(sqlite3*,const char*);
340 /* Version 3.36.1 and later */
341 sqlite3_int64 (*changes64)(sqlite3*);
342 sqlite3_int64 (*total_changes64)(sqlite3*);
343 /* Version 3.37.0 and later */
344 int (*autovacuum_pages)(sqlite3*,
345 unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
346 void*, void(*)(void*));
347 /* Version 3.38.0 and later */
348 int (*error_offset)(sqlite3*);
349 int (*vtab_rhs_value)(sqlite3_index_info*,int,sqlite3_value**);
350 int (*vtab_distinct)(sqlite3_index_info*);
351 int (*vtab_in)(sqlite3_index_info*,int,int);
352 int (*vtab_in_first)(sqlite3_value*,sqlite3_value**);
353 int (*vtab_in_next)(sqlite3_value*,sqlite3_value**);
354 /* Version 3.39.0 and later */
355 int (*deserialize)(sqlite3*,const char*,unsigned char*,
356 sqlite3_int64,sqlite3_int64,unsigned);
357 unsigned char *(*serialize)(sqlite3*,const char *,sqlite3_int64*,
358 unsigned int);
359 const char *(*db_name)(sqlite3*,int);
360};
361
362/*
363** This is the function signature used for all extension entry points. It
364** is also defined in the file "loadext.c".
365*/
366typedef int (*sqlite3_loadext_entry)(
367 sqlite3 *db, /* Handle to the database. */
368 char **pzErrMsg, /* Used to set error string on failure. */
369 const sqlite3_api_routines *pThunk /* Extension API function pointers. */
370);
371
372/*
373** The following macros redefine the API routines so that they are
374** redirected through the global sqlite3_api structure.
375**
376** This header file is also used by the loadext.c source file
377** (part of the main SQLite library - not an extension) so that
378** it can get access to the sqlite3_api_routines structure
379** definition. But the main library does not want to redefine
380** the API. So the redefinition macros are only valid if the
381** SQLITE_CORE macros is undefined.
382*/
383#if !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION)
384#ifndef SQLITE_OMIT_DEPRECATED
385#endif
386#ifndef SQLITE_OMIT_DEPRECATED
387#endif
388#ifndef SQLITE_OMIT_DEPRECATED
389#endif
390#ifndef SQLITE_OMIT_DEPRECATED
391#endif
392/* Version 3.7.16 and later */
393/* Version 3.8.7 and later */
394/* Version 3.8.11 and later */
395/* Version 3.9.0 and later */
396/* Version 3.10.0 and later */
397/* Version 3.12.0 and later */
398/* Version 3.14.0 and later */
399/* Version 3.18.0 and later */
400/* Version 3.20.0 and later */
401/* Version 3.22.0 and later */
402/* Version 3.24.0 and later */
403/* Version 3.25.0 and later */
404/* Version 3.26.0 and later */
405/* Version 3.28.0 and later */
406/* Version 3.30.0 and later */
407/* Version 3.31.0 and later */
408/* Version 3.32.0 and later */
409/* Version 3.34.0 and later */
410/* Version 3.36.1 and later */
411/* Version 3.37.0 and later */
412/* Version 3.38.0 and later */
413/* Version 3.39.0 and later */
414#ifndef SQLITE_OMIT_DESERIALIZE
415#endif
416#endif /* !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION) */
417
418#if !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION)
419 /* This case when the file really is being compiled as a loadable
420 ** extension */
421# define SQLITE_EXTENSION_INIT1 const sqlite3_api_routines *sqlite3_api=0;
422# define SQLITE_EXTENSION_INIT2(v) sqlite3_api=v;
423# define SQLITE_EXTENSION_INIT3 \
424 extern const sqlite3_api_routines *sqlite3_api;
425#else
426 /* This case when the file is being statically linked into the
427 ** application */
428# define SQLITE_EXTENSION_INIT1 /*no-op*/
429# define SQLITE_EXTENSION_INIT2(v) (void)v; /* unused parameter */
430# define SQLITE_EXTENSION_INIT3 /*no-op*/
431#endif
432
433#endif /* SQLITE3EXT_H */