4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
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.
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.
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.
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.
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.
35 #include <stdarg.h> /* Needed for the definition of va_list */
38 ** Make sure we can call this stuff from C++.
46 ** Provide the ability to override linkage features of the interface.
49 # define SQLITE_EXTERN extern
57 #ifndef SQLITE_APICALL
58 # define SQLITE_APICALL
60 #ifndef SQLITE_STDCALL
61 # define SQLITE_STDCALL SQLITE_APICALL
63 #ifndef SQLITE_CALLBACK
64 # define SQLITE_CALLBACK
67 # define SQLITE_SYSAPI
71 ** These no-op macros are used in front of interfaces to mark those
72 ** interfaces as either deprecated or experimental. New applications
73 ** should not use deprecated interfaces - they are supported for backwards
74 ** compatibility only. Application writers should be aware that
75 ** experimental interfaces are subject to change in point releases.
77 ** These macros used to resolve to various kinds of compiler magic that
78 ** would generate warning messages when they were used. But that
79 ** compiler magic ended up generating such a flurry of bug reports
80 ** that we have taken it all out and gone back to using simple
83 #define SQLITE_DEPRECATED
84 #define SQLITE_EXPERIMENTAL
87 ** Ensure these symbols were not defined by some previous header file.
90 # undef SQLITE_VERSION
92 #ifdef SQLITE_VERSION_NUMBER
93 # undef SQLITE_VERSION_NUMBER
97 ** CAPI3REF: Compile-Time Library Version Numbers
99 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
100 ** evaluates to a string literal that is the SQLite version in the
101 ** format "X.Y.Z" where X is the major version number (always 3 for
102 ** SQLite3) and Y is the minor version number and Z is the release number.)^
103 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
104 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
105 ** numbers used in [SQLITE_VERSION].)^
106 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
107 ** be larger than the release from which it is derived. Either Y will
108 ** be held constant and Z will be incremented or else Y will be incremented
109 ** and Z will be reset to zero.
111 ** Since [version 3.6.18] ([dateof:3.6.18]),
112 ** SQLite source code has been stored in the
113 ** <a href="http://www.fossil-scm.org/">Fossil configuration management
114 ** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to
115 ** a string which identifies a particular check-in of SQLite
116 ** within its configuration management system. ^The SQLITE_SOURCE_ID
117 ** string contains the date and time of the check-in (UTC) and a SHA1
118 ** or SHA3-256 hash of the entire source tree. If the source code has
119 ** been edited in any way since it was last checked in, then the last
120 ** four hexadecimal digits of the hash may be modified.
122 ** See also: [sqlite3_libversion()],
123 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
124 ** [sqlite_version()] and [sqlite_source_id()].
126 #define SQLITE_VERSION "3.21.0"
127 #define SQLITE_VERSION_NUMBER 3021000
128 #define SQLITE_SOURCE_ID "2017-10-24 18:55:49 1a584e499906b5c87ec7d43d4abce641fdf017c42125b083109bc77c4de48827"
131 ** CAPI3REF: Run-Time Library Version Numbers
132 ** KEYWORDS: sqlite3_version sqlite3_sourceid
134 ** These interfaces provide the same information as the [SQLITE_VERSION],
135 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
136 ** but are associated with the library instead of the header file. ^(Cautious
137 ** programmers might include assert() statements in their application to
138 ** verify that values returned by these interfaces match the macros in
139 ** the header, and thus ensure that the application is
140 ** compiled with matching library and header files.
143 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
144 ** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
145 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
146 ** </pre></blockquote>)^
148 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
149 ** macro. ^The sqlite3_libversion() function returns a pointer to the
150 ** to the sqlite3_version[] string constant. The sqlite3_libversion()
151 ** function is provided for use in DLLs since DLL users usually do not have
152 ** direct access to string constants within the DLL. ^The
153 ** sqlite3_libversion_number() function returns an integer equal to
154 ** [SQLITE_VERSION_NUMBER]. ^(The sqlite3_sourceid() function returns
155 ** a pointer to a string constant whose value is the same as the
156 ** [SQLITE_SOURCE_ID] C preprocessor macro. Except if SQLite is built
157 ** using an edited copy of [the amalgamation], then the last four characters
158 ** of the hash might be different from [SQLITE_SOURCE_ID].)^
160 ** See also: [sqlite_version()] and [sqlite_source_id()].
162 SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
163 SQLITE_API const char *sqlite3_libversion(void);
164 SQLITE_API const char *sqlite3_sourceid(void);
165 SQLITE_API int sqlite3_libversion_number(void);
168 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
170 ** ^The sqlite3_compileoption_used() function returns 0 or 1
171 ** indicating whether the specified option was defined at
172 ** compile time. ^The SQLITE_ prefix may be omitted from the
173 ** option name passed to sqlite3_compileoption_used().
175 ** ^The sqlite3_compileoption_get() function allows iterating
176 ** over the list of options that were defined at compile time by
177 ** returning the N-th compile time option string. ^If N is out of range,
178 ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
179 ** prefix is omitted from any strings returned by
180 ** sqlite3_compileoption_get().
182 ** ^Support for the diagnostic functions sqlite3_compileoption_used()
183 ** and sqlite3_compileoption_get() may be omitted by specifying the
184 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
186 ** See also: SQL functions [sqlite_compileoption_used()] and
187 ** [sqlite_compileoption_get()] and the [compile_options pragma].
189 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
190 SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
191 SQLITE_API const char *sqlite3_compileoption_get(int N);
195 ** CAPI3REF: Test To See If The Library Is Threadsafe
197 ** ^The sqlite3_threadsafe() function returns zero if and only if
198 ** SQLite was compiled with mutexing code omitted due to the
199 ** [SQLITE_THREADSAFE] compile-time option being set to 0.
201 ** SQLite can be compiled with or without mutexes. When
202 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
203 ** are enabled and SQLite is threadsafe. When the
204 ** [SQLITE_THREADSAFE] macro is 0,
205 ** the mutexes are omitted. Without the mutexes, it is not safe
206 ** to use SQLite concurrently from more than one thread.
208 ** Enabling mutexes incurs a measurable performance penalty.
209 ** So if speed is of utmost importance, it makes sense to disable
210 ** the mutexes. But for maximum safety, mutexes should be enabled.
211 ** ^The default behavior is for mutexes to be enabled.
213 ** This interface can be used by an application to make sure that the
214 ** version of SQLite that it is linking against was compiled with
215 ** the desired setting of the [SQLITE_THREADSAFE] macro.
217 ** This interface only reports on the compile-time mutex setting
218 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
219 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
220 ** can be fully or partially disabled using a call to [sqlite3_config()]
221 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
222 ** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the
223 ** sqlite3_threadsafe() function shows only the compile-time setting of
224 ** thread safety, not any run-time changes to that setting made by
225 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
226 ** is unchanged by calls to sqlite3_config().)^
228 ** See the [threading mode] documentation for additional information.
230 SQLITE_API int sqlite3_threadsafe(void);
233 ** CAPI3REF: Database Connection Handle
234 ** KEYWORDS: {database connection} {database connections}
236 ** Each open SQLite database is represented by a pointer to an instance of
237 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3
238 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
239 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
240 ** and [sqlite3_close_v2()] are its destructors. There are many other
241 ** interfaces (such as
242 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
243 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
246 typedef struct sqlite3 sqlite3;
249 ** CAPI3REF: 64-Bit Integer Types
250 ** KEYWORDS: sqlite_int64 sqlite_uint64
252 ** Because there is no cross-platform way to specify 64-bit integer types
253 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
255 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
256 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
257 ** compatibility only.
259 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
260 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
261 ** sqlite3_uint64 and sqlite_uint64 types can store integer values
262 ** between 0 and +18446744073709551615 inclusive.
264 #ifdef SQLITE_INT64_TYPE
265 typedef SQLITE_INT64_TYPE sqlite_int64;
266 # ifdef SQLITE_UINT64_TYPE
267 typedef SQLITE_UINT64_TYPE sqlite_uint64;
269 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
271 #elif defined(_MSC_VER) || defined(__BORLANDC__)
272 typedef __int64 sqlite_int64;
273 typedef unsigned __int64 sqlite_uint64;
275 typedef long long int sqlite_int64;
276 typedef unsigned long long int sqlite_uint64;
278 typedef sqlite_int64 sqlite3_int64;
279 typedef sqlite_uint64 sqlite3_uint64;
282 ** If compiling for a processor that lacks floating point support,
283 ** substitute integer for floating-point.
285 #ifdef SQLITE_OMIT_FLOATING_POINT
286 # define double sqlite3_int64
290 ** CAPI3REF: Closing A Database Connection
291 ** DESTRUCTOR: sqlite3
293 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
294 ** for the [sqlite3] object.
295 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
296 ** the [sqlite3] object is successfully destroyed and all associated
297 ** resources are deallocated.
299 ** ^If the database connection is associated with unfinalized prepared
300 ** statements or unfinished sqlite3_backup objects then sqlite3_close()
301 ** will leave the database connection open and return [SQLITE_BUSY].
302 ** ^If sqlite3_close_v2() is called with unfinalized prepared statements
303 ** and/or unfinished sqlite3_backups, then the database connection becomes
304 ** an unusable "zombie" which will automatically be deallocated when the
305 ** last prepared statement is finalized or the last sqlite3_backup is
306 ** finished. The sqlite3_close_v2() interface is intended for use with
307 ** host languages that are garbage collected, and where the order in which
308 ** destructors are called is arbitrary.
310 ** Applications should [sqlite3_finalize | finalize] all [prepared statements],
311 ** [sqlite3_blob_close | close] all [BLOB handles], and
312 ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
313 ** with the [sqlite3] object prior to attempting to close the object. ^If
314 ** sqlite3_close_v2() is called on a [database connection] that still has
315 ** outstanding [prepared statements], [BLOB handles], and/or
316 ** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
317 ** of resources is deferred until all [prepared statements], [BLOB handles],
318 ** and [sqlite3_backup] objects are also destroyed.
320 ** ^If an [sqlite3] object is destroyed while a transaction is open,
321 ** the transaction is automatically rolled back.
323 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
324 ** must be either a NULL
325 ** pointer or an [sqlite3] object pointer obtained
326 ** from [sqlite3_open()], [sqlite3_open16()], or
327 ** [sqlite3_open_v2()], and not previously closed.
328 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
329 ** argument is a harmless no-op.
331 SQLITE_API int sqlite3_close(sqlite3*);
332 SQLITE_API int sqlite3_close_v2(sqlite3*);
335 ** The type for a callback function.
336 ** This is legacy and deprecated. It is included for historical
337 ** compatibility and is not documented.
339 typedef int (*sqlite3_callback)(void*,int,char**, char**);
342 ** CAPI3REF: One-Step Query Execution Interface
345 ** The sqlite3_exec() interface is a convenience wrapper around
346 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
347 ** that allows an application to run multiple statements of SQL
348 ** without having to use a lot of C code.
350 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
351 ** semicolon-separate SQL statements passed into its 2nd argument,
352 ** in the context of the [database connection] passed in as its 1st
353 ** argument. ^If the callback function of the 3rd argument to
354 ** sqlite3_exec() is not NULL, then it is invoked for each result row
355 ** coming out of the evaluated SQL statements. ^The 4th argument to
356 ** sqlite3_exec() is relayed through to the 1st argument of each
357 ** callback invocation. ^If the callback pointer to sqlite3_exec()
358 ** is NULL, then no callback is ever invoked and result rows are
361 ** ^If an error occurs while evaluating the SQL statements passed into
362 ** sqlite3_exec(), then execution of the current statement stops and
363 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
364 ** is not NULL then any error message is written into memory obtained
365 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
366 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
367 ** on error message strings returned through the 5th parameter of
368 ** sqlite3_exec() after the error message string is no longer needed.
369 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
370 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
371 ** NULL before returning.
373 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
374 ** routine returns SQLITE_ABORT without invoking the callback again and
375 ** without running any subsequent SQL statements.
377 ** ^The 2nd argument to the sqlite3_exec() callback function is the
378 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
379 ** callback is an array of pointers to strings obtained as if from
380 ** [sqlite3_column_text()], one for each column. ^If an element of a
381 ** result row is NULL then the corresponding string pointer for the
382 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
383 ** sqlite3_exec() callback is an array of pointers to strings where each
384 ** entry represents the name of corresponding result column as obtained
385 ** from [sqlite3_column_name()].
387 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
388 ** to an empty string, or a pointer that contains only whitespace and/or
389 ** SQL comments, then no SQL statements are evaluated and the database
395 ** <li> The application must ensure that the 1st parameter to sqlite3_exec()
396 ** is a valid and open [database connection].
397 ** <li> The application must not close the [database connection] specified by
398 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
399 ** <li> The application must not modify the SQL statement text passed into
400 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
403 SQLITE_API int sqlite3_exec(
404 sqlite3*, /* An open database */
405 const char *sql, /* SQL to be evaluated */
406 int (*callback)(void*,int,char**,char**), /* Callback function */
407 void *, /* 1st argument to callback */
408 char **errmsg /* Error msg written here */
412 ** CAPI3REF: Result Codes
413 ** KEYWORDS: {result code definitions}
415 ** Many SQLite functions return an integer result code from the set shown
416 ** here in order to indicate success or failure.
418 ** New error codes may be added in future versions of SQLite.
420 ** See also: [extended result code definitions]
422 #define SQLITE_OK 0 /* Successful result */
423 /* beginning-of-error-codes */
424 #define SQLITE_ERROR 1 /* Generic error */
425 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
426 #define SQLITE_PERM 3 /* Access permission denied */
427 #define SQLITE_ABORT 4 /* Callback routine requested an abort */
428 #define SQLITE_BUSY 5 /* The database file is locked */
429 #define SQLITE_LOCKED 6 /* A table in the database is locked */
430 #define SQLITE_NOMEM 7 /* A malloc() failed */
431 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */
432 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
433 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
434 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */
435 #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
436 #define SQLITE_FULL 13 /* Insertion failed because database is full */
437 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */
438 #define SQLITE_PROTOCOL 15 /* Database lock protocol error */
439 #define SQLITE_EMPTY 16 /* Internal use only */
440 #define SQLITE_SCHEMA 17 /* The database schema changed */
441 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
442 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
443 #define SQLITE_MISMATCH 20 /* Data type mismatch */
444 #define SQLITE_MISUSE 21 /* Library used incorrectly */
445 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
446 #define SQLITE_AUTH 23 /* Authorization denied */
447 #define SQLITE_FORMAT 24 /* Not used */
448 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
449 #define SQLITE_NOTADB 26 /* File opened that is not a database file */
450 #define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */
451 #define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */
452 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
453 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
454 /* end-of-error-codes */
457 ** CAPI3REF: Extended Result Codes
458 ** KEYWORDS: {extended result code definitions}
460 ** In its default configuration, SQLite API routines return one of 30 integer
461 ** [result codes]. However, experience has shown that many of
462 ** these result codes are too coarse-grained. They do not provide as
463 ** much information about problems as programmers might like. In an effort to
464 ** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
465 ** and later) include
466 ** support for additional result codes that provide more detailed information
467 ** about errors. These [extended result codes] are enabled or disabled
468 ** on a per database connection basis using the
469 ** [sqlite3_extended_result_codes()] API. Or, the extended code for
470 ** the most recent error can be obtained using
471 ** [sqlite3_extended_errcode()].
473 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
474 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
475 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
476 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
477 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
478 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
479 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
480 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
481 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
482 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
483 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
484 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
485 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
486 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
487 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
488 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
489 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
490 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
491 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
492 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
493 #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
494 #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
495 #define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
496 #define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
497 #define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8))
498 #define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8))
499 #define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8))
500 #define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8))
501 #define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8))
502 #define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8))
503 #define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8))
504 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
505 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
506 #define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8))
507 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
508 #define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
509 #define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
510 #define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8))
511 #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
512 #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
513 #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
514 #define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8))
515 #define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8))
516 #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
517 #define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8))
518 #define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8))
519 #define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8))
520 #define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8))
521 #define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8))
522 #define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8))
523 #define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8))
524 #define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8))
525 #define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8))
526 #define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8))
527 #define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8))
528 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
529 #define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8))
530 #define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8))
531 #define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8))
534 ** CAPI3REF: Flags For File Open Operations
536 ** These bit values are intended for use in the
537 ** 3rd parameter to the [sqlite3_open_v2()] interface and
538 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
540 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
541 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
542 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
543 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
544 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
545 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
546 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
547 #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
548 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
549 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
550 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
551 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
552 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
553 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
554 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
555 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
556 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
557 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
558 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
559 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
561 /* Reserved: 0x00F00000 */
564 ** CAPI3REF: Device Characteristics
566 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
567 ** object returns an integer which is a vector of these
568 ** bit values expressing I/O characteristics of the mass storage
569 ** device that holds the file that the [sqlite3_io_methods]
572 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
573 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
574 ** mean that writes of blocks that are nnn bytes in size and
575 ** are aligned to an address which is an integer multiple of
576 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
577 ** that when data is appended to a file, the data is appended
578 ** first then the size of the file is extended, never the other
579 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
580 ** information is written to disk in the same order as calls
581 ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
582 ** after reboot following a crash or power loss, the only bytes in a
583 ** file that were written at the application level might have changed
584 ** and that adjacent bytes, even bytes within the same sector are
585 ** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
586 ** flag indicates that a file cannot be deleted when open. The
587 ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
588 ** read-only media and cannot be changed even by processes with
589 ** elevated privileges.
591 ** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
592 ** filesystem supports doing multiple write operations atomically when those
593 ** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
594 ** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
596 #define SQLITE_IOCAP_ATOMIC 0x00000001
597 #define SQLITE_IOCAP_ATOMIC512 0x00000002
598 #define SQLITE_IOCAP_ATOMIC1K 0x00000004
599 #define SQLITE_IOCAP_ATOMIC2K 0x00000008
600 #define SQLITE_IOCAP_ATOMIC4K 0x00000010
601 #define SQLITE_IOCAP_ATOMIC8K 0x00000020
602 #define SQLITE_IOCAP_ATOMIC16K 0x00000040
603 #define SQLITE_IOCAP_ATOMIC32K 0x00000080
604 #define SQLITE_IOCAP_ATOMIC64K 0x00000100
605 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
606 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
607 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
608 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
609 #define SQLITE_IOCAP_IMMUTABLE 0x00002000
610 #define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000
613 ** CAPI3REF: File Locking Levels
615 ** SQLite uses one of these integer values as the second
616 ** argument to calls it makes to the xLock() and xUnlock() methods
617 ** of an [sqlite3_io_methods] object.
619 #define SQLITE_LOCK_NONE 0
620 #define SQLITE_LOCK_SHARED 1
621 #define SQLITE_LOCK_RESERVED 2
622 #define SQLITE_LOCK_PENDING 3
623 #define SQLITE_LOCK_EXCLUSIVE 4
626 ** CAPI3REF: Synchronization Type Flags
628 ** When SQLite invokes the xSync() method of an
629 ** [sqlite3_io_methods] object it uses a combination of
630 ** these integer values as the second argument.
632 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
633 ** sync operation only needs to flush data to mass storage. Inode
634 ** information need not be flushed. If the lower four bits of the flag
635 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
636 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
637 ** to use Mac OS X style fullsync instead of fsync().
639 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
640 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
641 ** settings. The [synchronous pragma] determines when calls to the
642 ** xSync VFS method occur and applies uniformly across all platforms.
643 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
644 ** energetic or rigorous or forceful the sync operations are and
645 ** only make a difference on Mac OSX for the default SQLite code.
646 ** (Third-party VFS implementations might also make the distinction
647 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
648 ** operating systems natively supported by SQLite, only Mac OSX
649 ** cares about the difference.)
651 #define SQLITE_SYNC_NORMAL 0x00002
652 #define SQLITE_SYNC_FULL 0x00003
653 #define SQLITE_SYNC_DATAONLY 0x00010
656 ** CAPI3REF: OS Interface Open File Handle
658 ** An [sqlite3_file] object represents an open file in the
659 ** [sqlite3_vfs | OS interface layer]. Individual OS interface
660 ** implementations will
661 ** want to subclass this object by appending additional fields
662 ** for their own use. The pMethods entry is a pointer to an
663 ** [sqlite3_io_methods] object that defines methods for performing
664 ** I/O operations on the open file.
666 typedef struct sqlite3_file sqlite3_file;
667 struct sqlite3_file {
668 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
672 ** CAPI3REF: OS Interface File Virtual Methods Object
674 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
675 ** [sqlite3_file] object (or, more commonly, a subclass of the
676 ** [sqlite3_file] object) with a pointer to an instance of this object.
677 ** This object defines the methods used to perform various operations
678 ** against the open file represented by the [sqlite3_file] object.
680 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
681 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
682 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
683 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
684 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
687 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
688 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
689 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
690 ** flag may be ORed in to indicate that only the data of the file
691 ** and not its inode needs to be synced.
693 ** The integer values to xLock() and xUnlock() are one of
695 ** <li> [SQLITE_LOCK_NONE],
696 ** <li> [SQLITE_LOCK_SHARED],
697 ** <li> [SQLITE_LOCK_RESERVED],
698 ** <li> [SQLITE_LOCK_PENDING], or
699 ** <li> [SQLITE_LOCK_EXCLUSIVE].
701 ** xLock() increases the lock. xUnlock() decreases the lock.
702 ** The xCheckReservedLock() method checks whether any database connection,
703 ** either in this process or in some other process, is holding a RESERVED,
704 ** PENDING, or EXCLUSIVE lock on the file. It returns true
705 ** if such a lock exists and false otherwise.
707 ** The xFileControl() method is a generic interface that allows custom
708 ** VFS implementations to directly control an open file using the
709 ** [sqlite3_file_control()] interface. The second "op" argument is an
710 ** integer opcode. The third argument is a generic pointer intended to
711 ** point to a structure that may contain arguments or space in which to
712 ** write return values. Potential uses for xFileControl() might be
713 ** functions to enable blocking locks with timeouts, to change the
714 ** locking strategy (for example to use dot-file locks), to inquire
715 ** about the status of a lock, or to break stale locks. The SQLite
716 ** core reserves all opcodes less than 100 for its own use.
717 ** A [file control opcodes | list of opcodes] less than 100 is available.
718 ** Applications that define a custom xFileControl method should use opcodes
719 ** greater than 100 to avoid conflicts. VFS implementations should
720 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
723 ** The xSectorSize() method returns the sector size of the
724 ** device that underlies the file. The sector size is the
725 ** minimum write that can be performed without disturbing
726 ** other bytes in the file. The xDeviceCharacteristics()
727 ** method returns a bit vector describing behaviors of the
728 ** underlying device:
731 ** <li> [SQLITE_IOCAP_ATOMIC]
732 ** <li> [SQLITE_IOCAP_ATOMIC512]
733 ** <li> [SQLITE_IOCAP_ATOMIC1K]
734 ** <li> [SQLITE_IOCAP_ATOMIC2K]
735 ** <li> [SQLITE_IOCAP_ATOMIC4K]
736 ** <li> [SQLITE_IOCAP_ATOMIC8K]
737 ** <li> [SQLITE_IOCAP_ATOMIC16K]
738 ** <li> [SQLITE_IOCAP_ATOMIC32K]
739 ** <li> [SQLITE_IOCAP_ATOMIC64K]
740 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
741 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
742 ** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
743 ** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
744 ** <li> [SQLITE_IOCAP_IMMUTABLE]
745 ** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
748 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
749 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
750 ** mean that writes of blocks that are nnn bytes in size and
751 ** are aligned to an address which is an integer multiple of
752 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
753 ** that when data is appended to a file, the data is appended
754 ** first then the size of the file is extended, never the other
755 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
756 ** information is written to disk in the same order as calls
759 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
760 ** in the unread portions of the buffer with zeros. A VFS that
761 ** fails to zero-fill short reads might seem to work. However,
762 ** failure to zero-fill short reads will eventually lead to
763 ** database corruption.
765 typedef struct sqlite3_io_methods sqlite3_io_methods;
766 struct sqlite3_io_methods {
768 int (*xClose)(sqlite3_file*);
769 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
770 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
771 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
772 int (*xSync)(sqlite3_file*, int flags);
773 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
774 int (*xLock)(sqlite3_file*, int);
775 int (*xUnlock)(sqlite3_file*, int);
776 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
777 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
778 int (*xSectorSize)(sqlite3_file*);
779 int (*xDeviceCharacteristics)(sqlite3_file*);
780 /* Methods above are valid for version 1 */
781 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
782 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
783 void (*xShmBarrier)(sqlite3_file*);
784 int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
785 /* Methods above are valid for version 2 */
786 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
787 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
788 /* Methods above are valid for version 3 */
789 /* Additional methods may be added in future releases */
793 ** CAPI3REF: Standard File Control Opcodes
794 ** KEYWORDS: {file control opcodes} {file control opcode}
796 ** These integer constants are opcodes for the xFileControl method
797 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
801 ** <li>[[SQLITE_FCNTL_LOCKSTATE]]
802 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
803 ** opcode causes the xFileControl method to write the current state of
804 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
805 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
806 ** into an integer that the pArg argument points to. This capability
807 ** is used during testing and is only available when the SQLITE_TEST
808 ** compile-time option is used.
810 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
811 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
812 ** layer a hint of how large the database file will grow to be during the
813 ** current transaction. This hint is not guaranteed to be accurate but it
814 ** is often close. The underlying VFS might choose to preallocate database
815 ** file space based on this hint in order to help writes to the database
818 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
819 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
820 ** extends and truncates the database file in chunks of a size specified
821 ** by the user. The fourth argument to [sqlite3_file_control()] should
822 ** point to an integer (type int) containing the new chunk-size to use
823 ** for the nominated database. Allocating database file space in large
824 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
825 ** improve performance on some systems.
827 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
828 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
829 ** to the [sqlite3_file] object associated with a particular database
830 ** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER].
832 ** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
833 ** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
834 ** to the [sqlite3_file] object associated with the journal file (either
835 ** the [rollback journal] or the [write-ahead log]) for a particular database
836 ** connection. See also [SQLITE_FCNTL_FILE_POINTER].
838 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
841 ** <li>[[SQLITE_FCNTL_SYNC]]
842 ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
843 ** sent to the VFS immediately before the xSync method is invoked on a
844 ** database file descriptor. Or, if the xSync method is not invoked
845 ** because the user has configured SQLite with
846 ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
847 ** of the xSync method. In most cases, the pointer argument passed with
848 ** this file-control is NULL. However, if the database file is being synced
849 ** as part of a multi-database commit, the argument points to a nul-terminated
850 ** string containing the transactions master-journal file name. VFSes that
851 ** do not need this signal should silently ignore this opcode. Applications
852 ** should not call [sqlite3_file_control()] with this opcode as doing so may
853 ** disrupt the operation of the specialized VFSes that do require it.
855 ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
856 ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
857 ** and sent to the VFS after a transaction has been committed immediately
858 ** but before the database is unlocked. VFSes that do not need this signal
859 ** should silently ignore this opcode. Applications should not call
860 ** [sqlite3_file_control()] with this opcode as doing so may disrupt the
861 ** operation of the specialized VFSes that do require it.
863 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
864 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
865 ** retry counts and intervals for certain disk I/O operations for the
866 ** windows [VFS] in order to provide robustness in the presence of
867 ** anti-virus programs. By default, the windows VFS will retry file read,
868 ** file write, and file delete operations up to 10 times, with a delay
869 ** of 25 milliseconds before the first retry and with the delay increasing
870 ** by an additional 25 milliseconds with each subsequent retry. This
871 ** opcode allows these two values (10 retries and 25 milliseconds of delay)
872 ** to be adjusted. The values are changed for all database connections
873 ** within the same process. The argument is a pointer to an array of two
874 ** integers where the first integer is the new retry count and the second
875 ** integer is the delay. If either integer is negative, then the setting
876 ** is not changed but instead the prior value of that setting is written
877 ** into the array entry, allowing the current retry settings to be
878 ** interrogated. The zDbName parameter is ignored.
880 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
881 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
882 ** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
883 ** write ahead log and shared memory files used for transaction control
884 ** are automatically deleted when the latest connection to the database
885 ** closes. Setting persistent WAL mode causes those files to persist after
886 ** close. Persisting the files is useful when other processes that do not
887 ** have write permission on the directory containing the database file want
888 ** to read the database file, as the WAL and shared memory files must exist
889 ** in order for the database to be readable. The fourth parameter to
890 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
891 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
892 ** WAL mode. If the integer is -1, then it is overwritten with the current
893 ** WAL persistence setting.
895 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
896 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
897 ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
898 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
899 ** xDeviceCharacteristics methods. The fourth parameter to
900 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
901 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
902 ** mode. If the integer is -1, then it is overwritten with the current
903 ** zero-damage mode setting.
905 ** <li>[[SQLITE_FCNTL_OVERWRITE]]
906 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
907 ** a write transaction to indicate that, unless it is rolled back for some
908 ** reason, the entire database file will be overwritten by the current
909 ** transaction. This is used by VACUUM operations.
911 ** <li>[[SQLITE_FCNTL_VFSNAME]]
912 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
913 ** all [VFSes] in the VFS stack. The names are of all VFS shims and the
914 ** final bottom-level VFS are written into memory obtained from
915 ** [sqlite3_malloc()] and the result is stored in the char* variable
916 ** that the fourth parameter of [sqlite3_file_control()] points to.
917 ** The caller is responsible for freeing the memory when done. As with
918 ** all file-control actions, there is no guarantee that this will actually
919 ** do anything. Callers should initialize the char* variable to a NULL
920 ** pointer in case this file-control is not implemented. This file-control
921 ** is intended for diagnostic use only.
923 ** <li>[[SQLITE_FCNTL_VFS_POINTER]]
924 ** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
925 ** [VFSes] currently in use. ^(The argument X in
926 ** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
927 ** of type "[sqlite3_vfs] **". This opcodes will set *X
928 ** to a pointer to the top-level VFS.)^
929 ** ^When there are multiple VFS shims in the stack, this opcode finds the
930 ** upper-most shim only.
932 ** <li>[[SQLITE_FCNTL_PRAGMA]]
933 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
934 ** file control is sent to the open [sqlite3_file] object corresponding
935 ** to the database file to which the pragma statement refers. ^The argument
936 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
937 ** pointers to strings (char**) in which the second element of the array
938 ** is the name of the pragma and the third element is the argument to the
939 ** pragma or NULL if the pragma has no argument. ^The handler for an
940 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
941 ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
942 ** or the equivalent and that string will become the result of the pragma or
943 ** the error message if the pragma fails. ^If the
944 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
945 ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
946 ** file control returns [SQLITE_OK], then the parser assumes that the
947 ** VFS has handled the PRAGMA itself and the parser generates a no-op
948 ** prepared statement if result string is NULL, or that returns a copy
949 ** of the result string if the string is non-NULL.
950 ** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
951 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
952 ** that the VFS encountered an error while handling the [PRAGMA] and the
953 ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
954 ** file control occurs at the beginning of pragma statement analysis and so
955 ** it is able to override built-in [PRAGMA] statements.
957 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
958 ** ^The [SQLITE_FCNTL_BUSYHANDLER]
959 ** file-control may be invoked by SQLite on the database file handle
960 ** shortly after it is opened in order to provide a custom VFS with access
961 ** to the connections busy-handler callback. The argument is of type (void **)
962 ** - an array of two (void *) values. The first (void *) actually points
963 ** to a function of type (int (*)(void *)). In order to invoke the connections
964 ** busy-handler, this function should be invoked with the second (void *) in
965 ** the array as the only argument. If it returns non-zero, then the operation
966 ** should be retried. If it returns zero, the custom VFS should abandon the
967 ** current operation.
969 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
970 ** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
971 ** to have SQLite generate a
972 ** temporary filename using the same algorithm that is followed to generate
973 ** temporary filenames for TEMP tables and other internal uses. The
974 ** argument should be a char** which will be filled with the filename
975 ** written into memory obtained from [sqlite3_malloc()]. The caller should
976 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
978 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
979 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
980 ** maximum number of bytes that will be used for memory-mapped I/O.
981 ** The argument is a pointer to a value of type sqlite3_int64 that
982 ** is an advisory maximum number of bytes in the file to memory map. The
983 ** pointer is overwritten with the old value. The limit is not changed if
984 ** the value originally pointed to is negative, and so the current limit
985 ** can be queried by passing in a pointer to a negative number. This
986 ** file-control is used internally to implement [PRAGMA mmap_size].
988 ** <li>[[SQLITE_FCNTL_TRACE]]
989 ** The [SQLITE_FCNTL_TRACE] file control provides advisory information
990 ** to the VFS about what the higher layers of the SQLite stack are doing.
991 ** This file control is used by some VFS activity tracing [shims].
992 ** The argument is a zero-terminated string. Higher layers in the
993 ** SQLite stack may generate instances of this file control if
994 ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
996 ** <li>[[SQLITE_FCNTL_HAS_MOVED]]
997 ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
998 ** pointer to an integer and it writes a boolean into that integer depending
999 ** on whether or not the file has been renamed, moved, or deleted since it
1000 ** was first opened.
1002 ** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
1003 ** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
1004 ** underlying native file handle associated with a file handle. This file
1005 ** control interprets its argument as a pointer to a native file handle and
1006 ** writes the resulting value there.
1008 ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
1009 ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This
1010 ** opcode causes the xFileControl method to swap the file handle with the one
1011 ** pointed to by the pArg argument. This capability is used during testing
1012 ** and only needs to be supported when SQLITE_TEST is defined.
1014 ** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
1015 ** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
1016 ** be advantageous to block on the next WAL lock if the lock is not immediately
1017 ** available. The WAL subsystem issues this signal during rare
1018 ** circumstances in order to fix a problem with priority inversion.
1019 ** Applications should <em>not</em> use this file-control.
1021 ** <li>[[SQLITE_FCNTL_ZIPVFS]]
1022 ** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
1023 ** VFS should return SQLITE_NOTFOUND for this opcode.
1025 ** <li>[[SQLITE_FCNTL_RBU]]
1026 ** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
1027 ** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for
1030 ** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
1031 ** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
1032 ** the file descriptor is placed in "batch write mode", which
1033 ** means all subsequent write operations will be deferred and done
1034 ** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems
1035 ** that do not support batch atomic writes will return SQLITE_NOTFOUND.
1036 ** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
1037 ** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
1038 ** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
1039 ** no VFS interface calls on the same [sqlite3_file] file descriptor
1040 ** except for calls to the xWrite method and the xFileControl method
1041 ** with [SQLITE_FCNTL_SIZE_HINT].
1043 ** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
1044 ** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
1045 ** operations since the previous successful call to
1046 ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
1047 ** This file control returns [SQLITE_OK] if and only if the writes were
1048 ** all performed successfully and have been committed to persistent storage.
1049 ** ^Regardless of whether or not it is successful, this file control takes
1050 ** the file descriptor out of batch write mode so that all subsequent
1051 ** write operations are independent.
1052 ** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
1053 ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1055 ** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
1056 ** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
1057 ** operations since the previous successful call to
1058 ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
1059 ** ^This file control takes the file descriptor out of batch write mode
1060 ** so that all subsequent write operations are independent.
1061 ** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
1062 ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1065 #define SQLITE_FCNTL_LOCKSTATE 1
1066 #define SQLITE_FCNTL_GET_LOCKPROXYFILE 2
1067 #define SQLITE_FCNTL_SET_LOCKPROXYFILE 3
1068 #define SQLITE_FCNTL_LAST_ERRNO 4
1069 #define SQLITE_FCNTL_SIZE_HINT 5
1070 #define SQLITE_FCNTL_CHUNK_SIZE 6
1071 #define SQLITE_FCNTL_FILE_POINTER 7
1072 #define SQLITE_FCNTL_SYNC_OMITTED 8
1073 #define SQLITE_FCNTL_WIN32_AV_RETRY 9
1074 #define SQLITE_FCNTL_PERSIST_WAL 10
1075 #define SQLITE_FCNTL_OVERWRITE 11
1076 #define SQLITE_FCNTL_VFSNAME 12
1077 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
1078 #define SQLITE_FCNTL_PRAGMA 14
1079 #define SQLITE_FCNTL_BUSYHANDLER 15
1080 #define SQLITE_FCNTL_TEMPFILENAME 16
1081 #define SQLITE_FCNTL_MMAP_SIZE 18
1082 #define SQLITE_FCNTL_TRACE 19
1083 #define SQLITE_FCNTL_HAS_MOVED 20
1084 #define SQLITE_FCNTL_SYNC 21
1085 #define SQLITE_FCNTL_COMMIT_PHASETWO 22
1086 #define SQLITE_FCNTL_WIN32_SET_HANDLE 23
1087 #define SQLITE_FCNTL_WAL_BLOCK 24
1088 #define SQLITE_FCNTL_ZIPVFS 25
1089 #define SQLITE_FCNTL_RBU 26
1090 #define SQLITE_FCNTL_VFS_POINTER 27
1091 #define SQLITE_FCNTL_JOURNAL_POINTER 28
1092 #define SQLITE_FCNTL_WIN32_GET_HANDLE 29
1093 #define SQLITE_FCNTL_PDB 30
1094 #define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31
1095 #define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32
1096 #define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33
1098 /* deprecated names */
1099 #define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE
1100 #define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE
1101 #define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO
1105 ** CAPI3REF: Mutex Handle
1107 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
1108 ** abstract type for a mutex object. The SQLite core never looks
1109 ** at the internal representation of an [sqlite3_mutex]. It only
1110 ** deals with pointers to the [sqlite3_mutex] object.
1112 ** Mutexes are created using [sqlite3_mutex_alloc()].
1114 typedef struct sqlite3_mutex sqlite3_mutex;
1117 ** CAPI3REF: Loadable Extension Thunk
1119 ** A pointer to the opaque sqlite3_api_routines structure is passed as
1120 ** the third parameter to entry points of [loadable extensions]. This
1121 ** structure must be typedefed in order to work around compiler warnings
1122 ** on some platforms.
1124 typedef struct sqlite3_api_routines sqlite3_api_routines;
1127 ** CAPI3REF: OS Interface Object
1129 ** An instance of the sqlite3_vfs object defines the interface between
1130 ** the SQLite core and the underlying operating system. The "vfs"
1131 ** in the name of the object stands for "virtual file system". See
1132 ** the [VFS | VFS documentation] for further information.
1134 ** The value of the iVersion field is initially 1 but may be larger in
1135 ** future versions of SQLite. Additional fields may be appended to this
1136 ** object when the iVersion value is increased. Note that the structure
1137 ** of the sqlite3_vfs object changes in the transaction between
1138 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
1141 ** The szOsFile field is the size of the subclassed [sqlite3_file]
1142 ** structure used by this VFS. mxPathname is the maximum length of
1143 ** a pathname in this VFS.
1145 ** Registered sqlite3_vfs objects are kept on a linked list formed by
1146 ** the pNext pointer. The [sqlite3_vfs_register()]
1147 ** and [sqlite3_vfs_unregister()] interfaces manage this list
1148 ** in a thread-safe way. The [sqlite3_vfs_find()] interface
1149 ** searches the list. Neither the application code nor the VFS
1150 ** implementation should use the pNext pointer.
1152 ** The pNext field is the only field in the sqlite3_vfs
1153 ** structure that SQLite will ever modify. SQLite will only access
1154 ** or modify this field while holding a particular static mutex.
1155 ** The application should never modify anything within the sqlite3_vfs
1156 ** object once the object has been registered.
1158 ** The zName field holds the name of the VFS module. The name must
1159 ** be unique across all VFS modules.
1161 ** [[sqlite3_vfs.xOpen]]
1162 ** ^SQLite guarantees that the zFilename parameter to xOpen
1163 ** is either a NULL pointer or string obtained
1164 ** from xFullPathname() with an optional suffix added.
1165 ** ^If a suffix is added to the zFilename parameter, it will
1166 ** consist of a single "-" character followed by no more than
1167 ** 11 alphanumeric and/or "-" characters.
1168 ** ^SQLite further guarantees that
1169 ** the string will be valid and unchanged until xClose() is
1170 ** called. Because of the previous sentence,
1171 ** the [sqlite3_file] can safely store a pointer to the
1172 ** filename if it needs to remember the filename for some reason.
1173 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1174 ** must invent its own temporary name for the file. ^Whenever the
1175 ** xFilename parameter is NULL it will also be the case that the
1176 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1178 ** The flags argument to xOpen() includes all bits set in
1179 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
1180 ** or [sqlite3_open16()] is used, then flags includes at least
1181 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1182 ** If xOpen() opens a file read-only then it sets *pOutFlags to
1183 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
1185 ** ^(SQLite will also add one of the following flags to the xOpen()
1186 ** call, depending on the object being opened:
1189 ** <li> [SQLITE_OPEN_MAIN_DB]
1190 ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
1191 ** <li> [SQLITE_OPEN_TEMP_DB]
1192 ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
1193 ** <li> [SQLITE_OPEN_TRANSIENT_DB]
1194 ** <li> [SQLITE_OPEN_SUBJOURNAL]
1195 ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
1196 ** <li> [SQLITE_OPEN_WAL]
1199 ** The file I/O implementation can use the object type flags to
1200 ** change the way it deals with files. For example, an application
1201 ** that does not care about crash recovery or rollback might make
1202 ** the open of a journal file a no-op. Writes to this journal would
1203 ** also be no-ops, and any attempt to read the journal would return
1204 ** SQLITE_IOERR. Or the implementation might recognize that a database
1205 ** file will be doing page-aligned sector reads and writes in a random
1206 ** order and set up its I/O subsystem accordingly.
1208 ** SQLite might also add one of the following flags to the xOpen method:
1211 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
1212 ** <li> [SQLITE_OPEN_EXCLUSIVE]
1215 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1216 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1217 ** will be set for TEMP databases and their journals, transient
1218 ** databases, and subjournals.
1220 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1221 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1222 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1223 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1224 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1225 ** be created, and that it is an error if it already exists.
1226 ** It is <i>not</i> used to indicate the file should be opened
1227 ** for exclusive access.
1229 ** ^At least szOsFile bytes of memory are allocated by SQLite
1230 ** to hold the [sqlite3_file] structure passed as the third
1231 ** argument to xOpen. The xOpen method does not have to
1232 ** allocate the structure; it should just fill it in. Note that
1233 ** the xOpen method must set the sqlite3_file.pMethods to either
1234 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1235 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1236 ** element will be valid after xOpen returns regardless of the success
1237 ** or failure of the xOpen call.
1239 ** [[sqlite3_vfs.xAccess]]
1240 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1241 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1242 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1243 ** to test whether a file is at least readable. The file can be a
1246 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1247 ** output buffer xFullPathname. The exact size of the output buffer
1248 ** is also passed as a parameter to both methods. If the output buffer
1249 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1250 ** handled as a fatal error by SQLite, vfs implementations should endeavor
1251 ** to prevent this by setting mxPathname to a sufficiently large value.
1253 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1254 ** interfaces are not strictly a part of the filesystem, but they are
1255 ** included in the VFS structure for completeness.
1256 ** The xRandomness() function attempts to return nBytes bytes
1257 ** of good-quality randomness into zOut. The return value is
1258 ** the actual number of bytes of randomness obtained.
1259 ** The xSleep() method causes the calling thread to sleep for at
1260 ** least the number of microseconds given. ^The xCurrentTime()
1261 ** method returns a Julian Day Number for the current date and time as
1262 ** a floating point value.
1263 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1264 ** Day Number multiplied by 86400000 (the number of milliseconds in
1266 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1267 ** date and time if that method is available (if iVersion is 2 or
1268 ** greater and the function pointer is not NULL) and will fall back
1269 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1271 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1272 ** are not used by the SQLite core. These optional interfaces are provided
1273 ** by some VFSes to facilitate testing of the VFS code. By overriding
1274 ** system calls with functions under its control, a test program can
1275 ** simulate faults and error conditions that would otherwise be difficult
1276 ** or impossible to induce. The set of system calls that can be overridden
1277 ** varies from one VFS to another, and from one version of the same VFS to the
1278 ** next. Applications that use these interfaces must be prepared for any
1279 ** or all of these interfaces to be NULL or for their behavior to change
1280 ** from one release to the next. Applications must not attempt to access
1281 ** any of these methods if the iVersion of the VFS is less than 3.
1283 typedef struct sqlite3_vfs sqlite3_vfs;
1284 typedef void (*sqlite3_syscall_ptr)(void);
1285 struct sqlite3_vfs {
1286 int iVersion; /* Structure version number (currently 3) */
1287 int szOsFile; /* Size of subclassed sqlite3_file */
1288 int mxPathname; /* Maximum file pathname length */
1289 sqlite3_vfs *pNext; /* Next registered VFS */
1290 const char *zName; /* Name of this virtual file system */
1291 void *pAppData; /* Pointer to application-specific data */
1292 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1293 int flags, int *pOutFlags);
1294 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1295 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1296 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1297 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1298 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1299 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1300 void (*xDlClose)(sqlite3_vfs*, void*);
1301 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1302 int (*xSleep)(sqlite3_vfs*, int microseconds);
1303 int (*xCurrentTime)(sqlite3_vfs*, double*);
1304 int (*xGetLastError)(sqlite3_vfs*, int, char *);
1306 ** The methods above are in version 1 of the sqlite_vfs object
1307 ** definition. Those that follow are added in version 2 or later
1309 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1311 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1312 ** Those below are for version 3 and greater.
1314 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1315 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1316 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1318 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1319 ** New fields may be appended in future versions. The iVersion
1320 ** value will increment whenever this happens.
1325 ** CAPI3REF: Flags for the xAccess VFS method
1327 ** These integer constants can be used as the third parameter to
1328 ** the xAccess method of an [sqlite3_vfs] object. They determine
1329 ** what kind of permissions the xAccess method is looking for.
1330 ** With SQLITE_ACCESS_EXISTS, the xAccess method
1331 ** simply checks whether the file exists.
1332 ** With SQLITE_ACCESS_READWRITE, the xAccess method
1333 ** checks whether the named directory is both readable and writable
1334 ** (in other words, if files can be added, removed, and renamed within
1336 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1337 ** [temp_store_directory pragma], though this could change in a future
1338 ** release of SQLite.
1339 ** With SQLITE_ACCESS_READ, the xAccess method
1340 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1341 ** currently unused, though it might be used in a future release of
1344 #define SQLITE_ACCESS_EXISTS 0
1345 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1346 #define SQLITE_ACCESS_READ 2 /* Unused */
1349 ** CAPI3REF: Flags for the xShmLock VFS method
1351 ** These integer constants define the various locking operations
1352 ** allowed by the xShmLock method of [sqlite3_io_methods]. The
1353 ** following are the only legal combinations of flags to the
1357 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1358 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1359 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1360 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1363 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1364 ** was given on the corresponding lock.
1366 ** The xShmLock method can transition between unlocked and SHARED or
1367 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1370 #define SQLITE_SHM_UNLOCK 1
1371 #define SQLITE_SHM_LOCK 2
1372 #define SQLITE_SHM_SHARED 4
1373 #define SQLITE_SHM_EXCLUSIVE 8
1376 ** CAPI3REF: Maximum xShmLock index
1378 ** The xShmLock method on [sqlite3_io_methods] may use values
1379 ** between 0 and this upper bound as its "offset" argument.
1380 ** The SQLite core will never attempt to acquire or release a
1381 ** lock outside of this range
1383 #define SQLITE_SHM_NLOCK 8
1387 ** CAPI3REF: Initialize The SQLite Library
1389 ** ^The sqlite3_initialize() routine initializes the
1390 ** SQLite library. ^The sqlite3_shutdown() routine
1391 ** deallocates any resources that were allocated by sqlite3_initialize().
1392 ** These routines are designed to aid in process initialization and
1393 ** shutdown on embedded systems. Workstation applications using
1394 ** SQLite normally do not need to invoke either of these routines.
1396 ** A call to sqlite3_initialize() is an "effective" call if it is
1397 ** the first time sqlite3_initialize() is invoked during the lifetime of
1398 ** the process, or if it is the first time sqlite3_initialize() is invoked
1399 ** following a call to sqlite3_shutdown(). ^(Only an effective call
1400 ** of sqlite3_initialize() does any initialization. All other calls
1401 ** are harmless no-ops.)^
1403 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1404 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1405 ** an effective call to sqlite3_shutdown() does any deinitialization.
1406 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1408 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1409 ** is not. The sqlite3_shutdown() interface must only be called from a
1410 ** single thread. All open [database connections] must be closed and all
1411 ** other SQLite resources must be deallocated prior to invoking
1412 ** sqlite3_shutdown().
1414 ** Among other things, ^sqlite3_initialize() will invoke
1415 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1416 ** will invoke sqlite3_os_end().
1418 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1419 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1420 ** the library (perhaps it is unable to allocate a needed resource such
1421 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1423 ** ^The sqlite3_initialize() routine is called internally by many other
1424 ** SQLite interfaces so that an application usually does not need to
1425 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1426 ** calls sqlite3_initialize() so the SQLite library will be automatically
1427 ** initialized when [sqlite3_open()] is called if it has not be initialized
1428 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1429 ** compile-time option, then the automatic calls to sqlite3_initialize()
1430 ** are omitted and the application must call sqlite3_initialize() directly
1431 ** prior to using any other SQLite interface. For maximum portability,
1432 ** it is recommended that applications always invoke sqlite3_initialize()
1433 ** directly prior to using any other SQLite interface. Future releases
1434 ** of SQLite may require this. In other words, the behavior exhibited
1435 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1436 ** default behavior in some future release of SQLite.
1438 ** The sqlite3_os_init() routine does operating-system specific
1439 ** initialization of the SQLite library. The sqlite3_os_end()
1440 ** routine undoes the effect of sqlite3_os_init(). Typical tasks
1441 ** performed by these routines include allocation or deallocation
1442 ** of static resources, initialization of global variables,
1443 ** setting up a default [sqlite3_vfs] module, or setting up
1444 ** a default configuration using [sqlite3_config()].
1446 ** The application should never invoke either sqlite3_os_init()
1447 ** or sqlite3_os_end() directly. The application should only invoke
1448 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1449 ** interface is called automatically by sqlite3_initialize() and
1450 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1451 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1452 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1453 ** When [custom builds | built for other platforms]
1454 ** (using the [SQLITE_OS_OTHER=1] compile-time
1455 ** option) the application must supply a suitable implementation for
1456 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1457 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1458 ** must return [SQLITE_OK] on success and some other [error code] upon
1461 SQLITE_API int sqlite3_initialize(void);
1462 SQLITE_API int sqlite3_shutdown(void);
1463 SQLITE_API int sqlite3_os_init(void);
1464 SQLITE_API int sqlite3_os_end(void);
1467 ** CAPI3REF: Configuring The SQLite Library
1469 ** The sqlite3_config() interface is used to make global configuration
1470 ** changes to SQLite in order to tune SQLite to the specific needs of
1471 ** the application. The default configuration is recommended for most
1472 ** applications and so this routine is usually not necessary. It is
1473 ** provided to support rare applications with unusual needs.
1475 ** <b>The sqlite3_config() interface is not threadsafe. The application
1476 ** must ensure that no other SQLite interfaces are invoked by other
1477 ** threads while sqlite3_config() is running.</b>
1479 ** The sqlite3_config() interface
1480 ** may only be invoked prior to library initialization using
1481 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1482 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1483 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1484 ** Note, however, that ^sqlite3_config() can be called as part of the
1485 ** implementation of an application-defined [sqlite3_os_init()].
1487 ** The first argument to sqlite3_config() is an integer
1488 ** [configuration option] that determines
1489 ** what property of SQLite is to be configured. Subsequent arguments
1490 ** vary depending on the [configuration option]
1491 ** in the first argument.
1493 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1494 ** ^If the option is unknown or SQLite is unable to set the option
1495 ** then this routine returns a non-zero [error code].
1497 SQLITE_API int sqlite3_config(int, ...);
1500 ** CAPI3REF: Configure database connections
1503 ** The sqlite3_db_config() interface is used to make configuration
1504 ** changes to a [database connection]. The interface is similar to
1505 ** [sqlite3_config()] except that the changes apply to a single
1506 ** [database connection] (specified in the first argument).
1508 ** The second argument to sqlite3_db_config(D,V,...) is the
1509 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1510 ** that indicates what aspect of the [database connection] is being configured.
1511 ** Subsequent arguments vary depending on the configuration verb.
1513 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1514 ** the call is considered successful.
1516 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1519 ** CAPI3REF: Memory Allocation Routines
1521 ** An instance of this object defines the interface between SQLite
1522 ** and low-level memory allocation routines.
1524 ** This object is used in only one place in the SQLite interface.
1525 ** A pointer to an instance of this object is the argument to
1526 ** [sqlite3_config()] when the configuration option is
1527 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1528 ** By creating an instance of this object
1529 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1530 ** during configuration, an application can specify an alternative
1531 ** memory allocation subsystem for SQLite to use for all of its
1532 ** dynamic memory needs.
1534 ** Note that SQLite comes with several [built-in memory allocators]
1535 ** that are perfectly adequate for the overwhelming majority of applications
1536 ** and that this object is only useful to a tiny minority of applications
1537 ** with specialized memory allocation requirements. This object is
1538 ** also used during testing of SQLite in order to specify an alternative
1539 ** memory allocator that simulates memory out-of-memory conditions in
1540 ** order to verify that SQLite recovers gracefully from such
1543 ** The xMalloc, xRealloc, and xFree methods must work like the
1544 ** malloc(), realloc() and free() functions from the standard C library.
1545 ** ^SQLite guarantees that the second argument to
1546 ** xRealloc is always a value returned by a prior call to xRoundup.
1548 ** xSize should return the allocated size of a memory allocation
1549 ** previously obtained from xMalloc or xRealloc. The allocated size
1550 ** is always at least as big as the requested size but may be larger.
1552 ** The xRoundup method returns what would be the allocated size of
1553 ** a memory allocation given a particular requested size. Most memory
1554 ** allocators round up memory allocations at least to the next multiple
1555 ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1556 ** Every memory allocation request coming in through [sqlite3_malloc()]
1557 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1558 ** that causes the corresponding memory allocation to fail.
1560 ** The xInit method initializes the memory allocator. For example,
1561 ** it might allocate any require mutexes or initialize internal data
1562 ** structures. The xShutdown method is invoked (indirectly) by
1563 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1564 ** by xInit. The pAppData pointer is used as the only parameter to
1565 ** xInit and xShutdown.
1567 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1568 ** the xInit method, so the xInit method need not be threadsafe. The
1569 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1570 ** not need to be threadsafe either. For all other methods, SQLite
1571 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1572 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1573 ** it is by default) and so the methods are automatically serialized.
1574 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1575 ** methods must be threadsafe or else make their own arrangements for
1578 ** SQLite will never invoke xInit() more than once without an intervening
1579 ** call to xShutdown().
1581 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1582 struct sqlite3_mem_methods {
1583 void *(*xMalloc)(int); /* Memory allocation function */
1584 void (*xFree)(void*); /* Free a prior allocation */
1585 void *(*xRealloc)(void*,int); /* Resize an allocation */
1586 int (*xSize)(void*); /* Return the size of an allocation */
1587 int (*xRoundup)(int); /* Round up request size to allocation size */
1588 int (*xInit)(void*); /* Initialize the memory allocator */
1589 void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1590 void *pAppData; /* Argument to xInit() and xShutdown() */
1594 ** CAPI3REF: Configuration Options
1595 ** KEYWORDS: {configuration option}
1597 ** These constants are the available integer configuration options that
1598 ** can be passed as the first argument to the [sqlite3_config()] interface.
1600 ** New configuration options may be added in future releases of SQLite.
1601 ** Existing configuration options might be discontinued. Applications
1602 ** should check the return code from [sqlite3_config()] to make sure that
1603 ** the call worked. The [sqlite3_config()] interface will return a
1604 ** non-zero [error code] if a discontinued or unsupported configuration option
1608 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1609 ** <dd>There are no arguments to this option. ^This option sets the
1610 ** [threading mode] to Single-thread. In other words, it disables
1611 ** all mutexing and puts SQLite into a mode where it can only be used
1612 ** by a single thread. ^If SQLite is compiled with
1613 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1614 ** it is not possible to change the [threading mode] from its default
1615 ** value of Single-thread and so [sqlite3_config()] will return
1616 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1617 ** configuration option.</dd>
1619 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1620 ** <dd>There are no arguments to this option. ^This option sets the
1621 ** [threading mode] to Multi-thread. In other words, it disables
1622 ** mutexing on [database connection] and [prepared statement] objects.
1623 ** The application is responsible for serializing access to
1624 ** [database connections] and [prepared statements]. But other mutexes
1625 ** are enabled so that SQLite will be safe to use in a multi-threaded
1626 ** environment as long as no two threads attempt to use the same
1627 ** [database connection] at the same time. ^If SQLite is compiled with
1628 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1629 ** it is not possible to set the Multi-thread [threading mode] and
1630 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1631 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1633 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1634 ** <dd>There are no arguments to this option. ^This option sets the
1635 ** [threading mode] to Serialized. In other words, this option enables
1636 ** all mutexes including the recursive
1637 ** mutexes on [database connection] and [prepared statement] objects.
1638 ** In this mode (which is the default when SQLite is compiled with
1639 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1640 ** to [database connections] and [prepared statements] so that the
1641 ** application is free to use the same [database connection] or the
1642 ** same [prepared statement] in different threads at the same time.
1643 ** ^If SQLite is compiled with
1644 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1645 ** it is not possible to set the Serialized [threading mode] and
1646 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1647 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1649 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1650 ** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1651 ** a pointer to an instance of the [sqlite3_mem_methods] structure.
1652 ** The argument specifies
1653 ** alternative low-level memory allocation routines to be used in place of
1654 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1655 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1656 ** before the [sqlite3_config()] call returns.</dd>
1658 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1659 ** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1660 ** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1661 ** The [sqlite3_mem_methods]
1662 ** structure is filled with the currently defined memory allocation routines.)^
1663 ** This option can be used to overload the default memory allocation
1664 ** routines with a wrapper that simulations memory allocation failure or
1665 ** tracks memory usage, for example. </dd>
1667 ** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
1668 ** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
1669 ** type int, interpreted as a boolean, which if true provides a hint to
1670 ** SQLite that it should avoid large memory allocations if possible.
1671 ** SQLite will run faster if it is free to make large memory allocations,
1672 ** but some application might prefer to run slower in exchange for
1673 ** guarantees about memory fragmentation that are possible if large
1674 ** allocations are avoided. This hint is normally off.
1677 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1678 ** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1679 ** interpreted as a boolean, which enables or disables the collection of
1680 ** memory allocation statistics. ^(When memory allocation statistics are
1681 ** disabled, the following SQLite interfaces become non-operational:
1683 ** <li> [sqlite3_memory_used()]
1684 ** <li> [sqlite3_memory_highwater()]
1685 ** <li> [sqlite3_soft_heap_limit64()]
1686 ** <li> [sqlite3_status64()]
1688 ** ^Memory allocation statistics are enabled by default unless SQLite is
1689 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1690 ** allocation statistics are disabled by default.
1693 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1694 ** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
1697 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1698 ** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
1699 ** that SQLite can use for the database page cache with the default page
1700 ** cache implementation.
1701 ** This configuration option is a no-op if an application-define page
1702 ** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
1703 ** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1704 ** 8-byte aligned memory (pMem), the size of each page cache line (sz),
1705 ** and the number of cache lines (N).
1706 ** The sz argument should be the size of the largest database page
1707 ** (a power of two between 512 and 65536) plus some extra bytes for each
1708 ** page header. ^The number of extra bytes needed by the page header
1709 ** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
1710 ** ^It is harmless, apart from the wasted memory,
1711 ** for the sz parameter to be larger than necessary. The pMem
1712 ** argument must be either a NULL pointer or a pointer to an 8-byte
1713 ** aligned block of memory of at least sz*N bytes, otherwise
1714 ** subsequent behavior is undefined.
1715 ** ^When pMem is not NULL, SQLite will strive to use the memory provided
1716 ** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
1717 ** a page cache line is larger than sz bytes or if all of the pMem buffer
1719 ** ^If pMem is NULL and N is non-zero, then each database connection
1720 ** does an initial bulk allocation for page cache memory
1721 ** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
1722 ** of -1024*N bytes if N is negative, . ^If additional
1723 ** page cache memory is needed beyond what is provided by the initial
1724 ** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
1725 ** additional cache line. </dd>
1727 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1728 ** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1729 ** that SQLite will use for all of its dynamic memory allocation needs
1730 ** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
1731 ** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1732 ** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1733 ** [SQLITE_ERROR] if invoked otherwise.
1734 ** ^There are three arguments to SQLITE_CONFIG_HEAP:
1735 ** An 8-byte aligned pointer to the memory,
1736 ** the number of bytes in the memory buffer, and the minimum allocation size.
1737 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1738 ** to using its default memory allocator (the system malloc() implementation),
1739 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1740 ** memory pointer is not NULL then the alternative memory
1741 ** allocator is engaged to handle all of SQLites memory allocation needs.
1742 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1743 ** boundary or subsequent behavior of SQLite will be undefined.
1744 ** The minimum allocation size is capped at 2**12. Reasonable values
1745 ** for the minimum allocation size are 2**5 through 2**8.</dd>
1747 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1748 ** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1749 ** pointer to an instance of the [sqlite3_mutex_methods] structure.
1750 ** The argument specifies alternative low-level mutex routines to be used
1751 ** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of
1752 ** the content of the [sqlite3_mutex_methods] structure before the call to
1753 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1754 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1755 ** the entire mutexing subsystem is omitted from the build and hence calls to
1756 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1757 ** return [SQLITE_ERROR].</dd>
1759 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1760 ** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1761 ** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The
1762 ** [sqlite3_mutex_methods]
1763 ** structure is filled with the currently defined mutex routines.)^
1764 ** This option can be used to overload the default mutex allocation
1765 ** routines with a wrapper used to track mutex usage for performance
1766 ** profiling or testing, for example. ^If SQLite is compiled with
1767 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1768 ** the entire mutexing subsystem is omitted from the build and hence calls to
1769 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1770 ** return [SQLITE_ERROR].</dd>
1772 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1773 ** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1774 ** the default size of lookaside memory on each [database connection].
1775 ** The first argument is the
1776 ** size of each lookaside buffer slot and the second is the number of
1777 ** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE
1778 ** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1779 ** option to [sqlite3_db_config()] can be used to change the lookaside
1780 ** configuration on individual connections.)^ </dd>
1782 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1783 ** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1784 ** a pointer to an [sqlite3_pcache_methods2] object. This object specifies
1785 ** the interface to a custom page cache implementation.)^
1786 ** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1788 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1789 ** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1790 ** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of
1791 ** the current page cache implementation into that object.)^ </dd>
1793 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1794 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1795 ** global [error log].
1796 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1797 ** function with a call signature of void(*)(void*,int,const char*),
1798 ** and a pointer to void. ^If the function pointer is not NULL, it is
1799 ** invoked by [sqlite3_log()] to process each logging event. ^If the
1800 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1801 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1802 ** passed through as the first parameter to the application-defined logger
1803 ** function whenever that function is invoked. ^The second parameter to
1804 ** the logger function is a copy of the first parameter to the corresponding
1805 ** [sqlite3_log()] call and is intended to be a [result code] or an
1806 ** [extended result code]. ^The third parameter passed to the logger is
1807 ** log message after formatting via [sqlite3_snprintf()].
1808 ** The SQLite logging interface is not reentrant; the logger function
1809 ** supplied by the application must not invoke any SQLite interface.
1810 ** In a multi-threaded application, the application-defined logger
1811 ** function must be threadsafe. </dd>
1813 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1814 ** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1815 ** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1816 ** then URI handling is globally disabled.)^ ^If URI handling is globally
1817 ** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1818 ** [sqlite3_open16()] or
1819 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1820 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1821 ** connection is opened. ^If it is globally disabled, filenames are
1822 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1823 ** database connection is opened. ^(By default, URI handling is globally
1824 ** disabled. The default value may be changed by compiling with the
1825 ** [SQLITE_USE_URI] symbol defined.)^
1827 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1828 ** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1829 ** argument which is interpreted as a boolean in order to enable or disable
1830 ** the use of covering indices for full table scans in the query optimizer.
1831 ** ^The default setting is determined
1832 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1833 ** if that compile-time option is omitted.
1834 ** The ability to disable the use of covering indices for full table scans
1835 ** is because some incorrectly coded legacy applications might malfunction
1836 ** when the optimization is enabled. Providing the ability to
1837 ** disable the optimization allows the older, buggy application code to work
1838 ** without change even with newer versions of SQLite.
1840 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1841 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1842 ** <dd> These options are obsolete and should not be used by new code.
1843 ** They are retained for backwards compatibility but are now no-ops.
1846 ** [[SQLITE_CONFIG_SQLLOG]]
1847 ** <dt>SQLITE_CONFIG_SQLLOG
1848 ** <dd>This option is only available if sqlite is compiled with the
1849 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1850 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1851 ** The second should be of type (void*). The callback is invoked by the library
1852 ** in three separate circumstances, identified by the value passed as the
1853 ** fourth parameter. If the fourth parameter is 0, then the database connection
1854 ** passed as the second argument has just been opened. The third argument
1855 ** points to a buffer containing the name of the main database file. If the
1856 ** fourth parameter is 1, then the SQL statement that the third parameter
1857 ** points to has just been executed. Or, if the fourth parameter is 2, then
1858 ** the connection being passed as the second parameter is being closed. The
1859 ** third parameter is passed NULL In this case. An example of using this
1860 ** configuration option can be seen in the "test_sqllog.c" source file in
1861 ** the canonical SQLite source tree.</dd>
1863 ** [[SQLITE_CONFIG_MMAP_SIZE]]
1864 ** <dt>SQLITE_CONFIG_MMAP_SIZE
1865 ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1866 ** that are the default mmap size limit (the default setting for
1867 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1868 ** ^The default setting can be overridden by each database connection using
1869 ** either the [PRAGMA mmap_size] command, or by using the
1870 ** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size
1871 ** will be silently truncated if necessary so that it does not exceed the
1872 ** compile-time maximum mmap size set by the
1873 ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1874 ** ^If either argument to this option is negative, then that argument is
1875 ** changed to its compile-time default.
1877 ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
1878 ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
1879 ** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
1880 ** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
1881 ** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1882 ** that specifies the maximum size of the created heap.
1884 ** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
1885 ** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
1886 ** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
1887 ** is a pointer to an integer and writes into that integer the number of extra
1888 ** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
1889 ** The amount of extra space required can change depending on the compiler,
1890 ** target platform, and SQLite version.
1892 ** [[SQLITE_CONFIG_PMASZ]]
1893 ** <dt>SQLITE_CONFIG_PMASZ
1894 ** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
1895 ** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
1896 ** sorter to that integer. The default minimum PMA Size is set by the
1897 ** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched
1898 ** to help with sort operations when multithreaded sorting
1899 ** is enabled (using the [PRAGMA threads] command) and the amount of content
1900 ** to be sorted exceeds the page size times the minimum of the
1901 ** [PRAGMA cache_size] setting and this value.
1903 ** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
1904 ** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
1905 ** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
1906 ** becomes the [statement journal] spill-to-disk threshold.
1907 ** [Statement journals] are held in memory until their size (in bytes)
1908 ** exceeds this threshold, at which point they are written to disk.
1909 ** Or if the threshold is -1, statement journals are always held
1910 ** exclusively in memory.
1911 ** Since many statement journals never become large, setting the spill
1912 ** threshold to a value such as 64KiB can greatly reduce the amount of
1913 ** I/O required to support statement rollback.
1914 ** The default value for this setting is controlled by the
1915 ** [SQLITE_STMTJRNL_SPILL] compile-time option.
1918 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1919 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1920 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1921 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1922 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1923 #define SQLITE_CONFIG_SCRATCH 6 /* No longer used */
1924 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1925 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1926 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1927 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1928 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1929 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1930 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1931 #define SQLITE_CONFIG_PCACHE 14 /* no-op */
1932 #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
1933 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
1934 #define SQLITE_CONFIG_URI 17 /* int */
1935 #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
1936 #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
1937 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
1938 #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
1939 #define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
1940 #define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
1941 #define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */
1942 #define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */
1943 #define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */
1944 #define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */
1947 ** CAPI3REF: Database Connection Configuration Options
1949 ** These constants are the available integer configuration options that
1950 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1952 ** New configuration options may be added in future releases of SQLite.
1953 ** Existing configuration options might be discontinued. Applications
1954 ** should check the return code from [sqlite3_db_config()] to make sure that
1955 ** the call worked. ^The [sqlite3_db_config()] interface will return a
1956 ** non-zero [error code] if a discontinued or unsupported configuration option
1960 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1961 ** <dd> ^This option takes three additional arguments that determine the
1962 ** [lookaside memory allocator] configuration for the [database connection].
1963 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1964 ** pointer to a memory buffer to use for lookaside memory.
1965 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1966 ** may be NULL in which case SQLite will allocate the
1967 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1968 ** size of each lookaside buffer slot. ^The third argument is the number of
1969 ** slots. The size of the buffer in the first argument must be greater than
1970 ** or equal to the product of the second and third arguments. The buffer
1971 ** must be aligned to an 8-byte boundary. ^If the second argument to
1972 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1973 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
1974 ** configuration for a database connection can only be changed when that
1975 ** connection is not currently using lookaside memory, or in other words
1976 ** when the "current value" returned by
1977 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1978 ** Any attempt to change the lookaside memory configuration when lookaside
1979 ** memory is in use leaves the configuration unchanged and returns
1980 ** [SQLITE_BUSY].)^</dd>
1982 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1983 ** <dd> ^This option is used to enable or disable the enforcement of
1984 ** [foreign key constraints]. There should be two additional arguments.
1985 ** The first argument is an integer which is 0 to disable FK enforcement,
1986 ** positive to enable FK enforcement or negative to leave FK enforcement
1987 ** unchanged. The second parameter is a pointer to an integer into which
1988 ** is written 0 or 1 to indicate whether FK enforcement is off or on
1989 ** following this call. The second parameter may be a NULL pointer, in
1990 ** which case the FK enforcement setting is not reported back. </dd>
1992 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1993 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1994 ** There should be two additional arguments.
1995 ** The first argument is an integer which is 0 to disable triggers,
1996 ** positive to enable triggers or negative to leave the setting unchanged.
1997 ** The second parameter is a pointer to an integer into which
1998 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
1999 ** following this call. The second parameter may be a NULL pointer, in
2000 ** which case the trigger setting is not reported back. </dd>
2002 ** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
2003 ** <dd> ^This option is used to enable or disable the two-argument
2004 ** version of the [fts3_tokenizer()] function which is part of the
2005 ** [FTS3] full-text search engine extension.
2006 ** There should be two additional arguments.
2007 ** The first argument is an integer which is 0 to disable fts3_tokenizer() or
2008 ** positive to enable fts3_tokenizer() or negative to leave the setting
2010 ** The second parameter is a pointer to an integer into which
2011 ** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
2012 ** following this call. The second parameter may be a NULL pointer, in
2013 ** which case the new setting is not reported back. </dd>
2015 ** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
2016 ** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
2017 ** interface independently of the [load_extension()] SQL function.
2018 ** The [sqlite3_enable_load_extension()] API enables or disables both the
2019 ** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
2020 ** There should be two additional arguments.
2021 ** When the first argument to this interface is 1, then only the C-API is
2022 ** enabled and the SQL function remains disabled. If the first argument to
2023 ** this interface is 0, then both the C-API and the SQL function are disabled.
2024 ** If the first argument is -1, then no changes are made to state of either the
2025 ** C-API or the SQL function.
2026 ** The second parameter is a pointer to an integer into which
2027 ** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
2028 ** is disabled or enabled following this call. The second parameter may
2029 ** be a NULL pointer, in which case the new setting is not reported back.
2032 ** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
2033 ** <dd> ^This option is used to change the name of the "main" database
2034 ** schema. ^The sole argument is a pointer to a constant UTF8 string
2035 ** which will become the new schema name in place of "main". ^SQLite
2036 ** does not make a copy of the new main schema name string, so the application
2037 ** must ensure that the argument passed into this DBCONFIG option is unchanged
2038 ** until after the database connection closes.
2041 ** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
2042 ** <dd> Usually, when a database in wal mode is closed or detached from a
2043 ** database handle, SQLite checks if this will mean that there are now no
2044 ** connections at all to the database. If so, it performs a checkpoint
2045 ** operation before closing the connection. This option may be used to
2046 ** override this behaviour. The first parameter passed to this operation
2047 ** is an integer - non-zero to disable checkpoints-on-close, or zero (the
2048 ** default) to enable them. The second parameter is a pointer to an integer
2049 ** into which is written 0 or 1 to indicate whether checkpoints-on-close
2050 ** have been disabled - 0 if they are not disabled, 1 if they are.
2053 ** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
2054 ** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
2055 ** the [query planner stability guarantee] (QPSG). When the QPSG is active,
2056 ** a single SQL query statement will always use the same algorithm regardless
2057 ** of values of [bound parameters].)^ The QPSG disables some query optimizations
2058 ** that look at the values of bound parameters, which can make some queries
2059 ** slower. But the QPSG has the advantage of more predictable behavior. With
2060 ** the QPSG active, SQLite will always use the same query plan in the field as
2061 ** was used during testing in the lab.
2066 #define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */
2067 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
2068 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
2069 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
2070 #define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
2071 #define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
2072 #define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */
2073 #define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */
2077 ** CAPI3REF: Enable Or Disable Extended Result Codes
2080 ** ^The sqlite3_extended_result_codes() routine enables or disables the
2081 ** [extended result codes] feature of SQLite. ^The extended result
2082 ** codes are disabled by default for historical compatibility.
2084 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
2087 ** CAPI3REF: Last Insert Rowid
2090 ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
2091 ** has a unique 64-bit signed
2092 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
2093 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
2094 ** names are not also used by explicitly declared columns. ^If
2095 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
2096 ** is another alias for the rowid.
2098 ** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
2099 ** the most recent successful [INSERT] into a rowid table or [virtual table]
2100 ** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
2101 ** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
2102 ** on the database connection D, then sqlite3_last_insert_rowid(D) returns
2105 ** As well as being set automatically as rows are inserted into database
2106 ** tables, the value returned by this function may be set explicitly by
2107 ** [sqlite3_set_last_insert_rowid()]
2109 ** Some virtual table implementations may INSERT rows into rowid tables as
2110 ** part of committing a transaction (e.g. to flush data accumulated in memory
2111 ** to disk). In this case subsequent calls to this function return the rowid
2112 ** associated with these internal INSERT operations, which leads to
2113 ** unintuitive results. Virtual table implementations that do write to rowid
2114 ** tables in this way can avoid this problem by restoring the original
2115 ** rowid value using [sqlite3_set_last_insert_rowid()] before returning
2116 ** control to the user.
2118 ** ^(If an [INSERT] occurs within a trigger then this routine will
2119 ** return the [rowid] of the inserted row as long as the trigger is
2120 ** running. Once the trigger program ends, the value returned
2121 ** by this routine reverts to what it was before the trigger was fired.)^
2123 ** ^An [INSERT] that fails due to a constraint violation is not a
2124 ** successful [INSERT] and does not change the value returned by this
2125 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
2126 ** and INSERT OR ABORT make no changes to the return value of this
2127 ** routine when their insertion fails. ^(When INSERT OR REPLACE
2128 ** encounters a constraint violation, it does not fail. The
2129 ** INSERT continues to completion after deleting rows that caused
2130 ** the constraint problem so INSERT OR REPLACE will always change
2131 ** the return value of this interface.)^
2133 ** ^For the purposes of this routine, an [INSERT] is considered to
2134 ** be successful even if it is subsequently rolled back.
2136 ** This function is accessible to SQL statements via the
2137 ** [last_insert_rowid() SQL function].
2139 ** If a separate thread performs a new [INSERT] on the same
2140 ** database connection while the [sqlite3_last_insert_rowid()]
2141 ** function is running and thus changes the last insert [rowid],
2142 ** then the value returned by [sqlite3_last_insert_rowid()] is
2143 ** unpredictable and might not equal either the old or the new
2144 ** last insert [rowid].
2146 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
2149 ** CAPI3REF: Set the Last Insert Rowid value.
2152 ** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
2153 ** set the value returned by calling sqlite3_last_insert_rowid(D) to R
2154 ** without inserting a row into the database.
2156 SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
2159 ** CAPI3REF: Count The Number Of Rows Modified
2162 ** ^This function returns the number of rows modified, inserted or
2163 ** deleted by the most recently completed INSERT, UPDATE or DELETE
2164 ** statement on the database connection specified by the only parameter.
2165 ** ^Executing any other type of SQL statement does not modify the value
2166 ** returned by this function.
2168 ** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
2169 ** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
2170 ** [foreign key actions] or [REPLACE] constraint resolution are not counted.
2172 ** Changes to a view that are intercepted by
2173 ** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
2174 ** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
2175 ** DELETE statement run on a view is always zero. Only changes made to real
2176 ** tables are counted.
2178 ** Things are more complicated if the sqlite3_changes() function is
2179 ** executed while a trigger program is running. This may happen if the
2180 ** program uses the [changes() SQL function], or if some other callback
2181 ** function invokes sqlite3_changes() directly. Essentially:
2184 ** <li> ^(Before entering a trigger program the value returned by
2185 ** sqlite3_changes() function is saved. After the trigger program
2186 ** has finished, the original value is restored.)^
2188 ** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
2189 ** statement sets the value returned by sqlite3_changes()
2190 ** upon completion as normal. Of course, this value will not include
2191 ** any changes performed by sub-triggers, as the sqlite3_changes()
2192 ** value will be saved and restored after each sub-trigger has run.)^
2195 ** ^This means that if the changes() SQL function (or similar) is used
2196 ** by the first INSERT, UPDATE or DELETE statement within a trigger, it
2197 ** returns the value as set when the calling statement began executing.
2198 ** ^If it is used by the second or subsequent such statement within a trigger
2199 ** program, the value returned reflects the number of rows modified by the
2200 ** previous INSERT, UPDATE or DELETE statement within the same trigger.
2202 ** See also the [sqlite3_total_changes()] interface, the
2203 ** [count_changes pragma], and the [changes() SQL function].
2205 ** If a separate thread makes changes on the same database connection
2206 ** while [sqlite3_changes()] is running then the value returned
2207 ** is unpredictable and not meaningful.
2209 SQLITE_API int sqlite3_changes(sqlite3*);
2212 ** CAPI3REF: Total Number Of Rows Modified
2215 ** ^This function returns the total number of rows inserted, modified or
2216 ** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2217 ** since the database connection was opened, including those executed as
2218 ** part of trigger programs. ^Executing any other type of SQL statement
2219 ** does not affect the value returned by sqlite3_total_changes().
2221 ** ^Changes made as part of [foreign key actions] are included in the
2222 ** count, but those made as part of REPLACE constraint resolution are
2223 ** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2226 ** See also the [sqlite3_changes()] interface, the
2227 ** [count_changes pragma], and the [total_changes() SQL function].
2229 ** If a separate thread makes changes on the same database connection
2230 ** while [sqlite3_total_changes()] is running then the value
2231 ** returned is unpredictable and not meaningful.
2233 SQLITE_API int sqlite3_total_changes(sqlite3*);
2236 ** CAPI3REF: Interrupt A Long-Running Query
2239 ** ^This function causes any pending database operation to abort and
2240 ** return at its earliest opportunity. This routine is typically
2241 ** called in response to a user action such as pressing "Cancel"
2242 ** or Ctrl-C where the user wants a long query operation to halt
2245 ** ^It is safe to call this routine from a thread different from the
2246 ** thread that is currently running the database operation. But it
2247 ** is not safe to call this routine with a [database connection] that
2248 ** is closed or might close before sqlite3_interrupt() returns.
2250 ** ^If an SQL operation is very nearly finished at the time when
2251 ** sqlite3_interrupt() is called, then it might not have an opportunity
2252 ** to be interrupted and might continue to completion.
2254 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2255 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2256 ** that is inside an explicit transaction, then the entire transaction
2257 ** will be rolled back automatically.
2259 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
2260 ** SQL statements on [database connection] D complete. ^Any new SQL statements
2261 ** that are started after the sqlite3_interrupt() call and before the
2262 ** running statements reaches zero are interrupted as if they had been
2263 ** running prior to the sqlite3_interrupt() call. ^New SQL statements
2264 ** that are started after the running statement count reaches zero are
2265 ** not effected by the sqlite3_interrupt().
2266 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2267 ** SQL statements is a no-op and has no effect on SQL statements
2268 ** that are started after the sqlite3_interrupt() call returns.
2270 SQLITE_API void sqlite3_interrupt(sqlite3*);
2273 ** CAPI3REF: Determine If An SQL Statement Is Complete
2275 ** These routines are useful during command-line input to determine if the
2276 ** currently entered text seems to form a complete SQL statement or
2277 ** if additional input is needed before sending the text into
2278 ** SQLite for parsing. ^These routines return 1 if the input string
2279 ** appears to be a complete SQL statement. ^A statement is judged to be
2280 ** complete if it ends with a semicolon token and is not a prefix of a
2281 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
2282 ** string literals or quoted identifier names or comments are not
2283 ** independent tokens (they are part of the token in which they are
2284 ** embedded) and thus do not count as a statement terminator. ^Whitespace
2285 ** and comments that follow the final semicolon are ignored.
2287 ** ^These routines return 0 if the statement is incomplete. ^If a
2288 ** memory allocation fails, then SQLITE_NOMEM is returned.
2290 ** ^These routines do not parse the SQL statements thus
2291 ** will not detect syntactically incorrect SQL.
2293 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2294 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2295 ** automatically by sqlite3_complete16(). If that initialization fails,
2296 ** then the return value from sqlite3_complete16() will be non-zero
2297 ** regardless of whether or not the input SQL is complete.)^
2299 ** The input to [sqlite3_complete()] must be a zero-terminated
2302 ** The input to [sqlite3_complete16()] must be a zero-terminated
2303 ** UTF-16 string in native byte order.
2305 SQLITE_API int sqlite3_complete(const char *sql);
2306 SQLITE_API int sqlite3_complete16(const void *sql);
2309 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2310 ** KEYWORDS: {busy-handler callback} {busy handler}
2313 ** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2314 ** that might be invoked with argument P whenever
2315 ** an attempt is made to access a database table associated with
2316 ** [database connection] D when another thread
2317 ** or process has the table locked.
2318 ** The sqlite3_busy_handler() interface is used to implement
2319 ** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2321 ** ^If the busy callback is NULL, then [SQLITE_BUSY]
2322 ** is returned immediately upon encountering the lock. ^If the busy callback
2323 ** is not NULL, then the callback might be invoked with two arguments.
2325 ** ^The first argument to the busy handler is a copy of the void* pointer which
2326 ** is the third argument to sqlite3_busy_handler(). ^The second argument to
2327 ** the busy handler callback is the number of times that the busy handler has
2328 ** been invoked previously for the same locking event. ^If the
2329 ** busy callback returns 0, then no additional attempts are made to
2330 ** access the database and [SQLITE_BUSY] is returned
2331 ** to the application.
2332 ** ^If the callback returns non-zero, then another attempt
2333 ** is made to access the database and the cycle repeats.
2335 ** The presence of a busy handler does not guarantee that it will be invoked
2336 ** when there is lock contention. ^If SQLite determines that invoking the busy
2337 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2338 ** to the application instead of invoking the
2340 ** Consider a scenario where one process is holding a read lock that
2341 ** it is trying to promote to a reserved lock and
2342 ** a second process is holding a reserved lock that it is trying
2343 ** to promote to an exclusive lock. The first process cannot proceed
2344 ** because it is blocked by the second and the second process cannot
2345 ** proceed because it is blocked by the first. If both processes
2346 ** invoke the busy handlers, neither will make any progress. Therefore,
2347 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2348 ** will induce the first process to release its read lock and allow
2349 ** the second process to proceed.
2351 ** ^The default busy callback is NULL.
2353 ** ^(There can only be a single busy handler defined for each
2354 ** [database connection]. Setting a new busy handler clears any
2355 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
2356 ** or evaluating [PRAGMA busy_timeout=N] will change the
2357 ** busy handler and thus clear any previously set busy handler.
2359 ** The busy callback should not take any actions which modify the
2360 ** database connection that invoked the busy handler. In other words,
2361 ** the busy handler is not reentrant. Any such actions
2362 ** result in undefined behavior.
2364 ** A busy handler must not close the database connection
2365 ** or [prepared statement] that invoked the busy handler.
2367 SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
2370 ** CAPI3REF: Set A Busy Timeout
2373 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2374 ** for a specified amount of time when a table is locked. ^The handler
2375 ** will sleep multiple times until at least "ms" milliseconds of sleeping
2376 ** have accumulated. ^After at least "ms" milliseconds of sleeping,
2377 ** the handler returns 0 which causes [sqlite3_step()] to return
2380 ** ^Calling this routine with an argument less than or equal to zero
2381 ** turns off all busy handlers.
2383 ** ^(There can only be a single busy handler for a particular
2384 ** [database connection] at any given moment. If another busy handler
2385 ** was defined (using [sqlite3_busy_handler()]) prior to calling
2386 ** this routine, that other busy handler is cleared.)^
2388 ** See also: [PRAGMA busy_timeout]
2390 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2393 ** CAPI3REF: Convenience Routines For Running Queries
2396 ** This is a legacy interface that is preserved for backwards compatibility.
2397 ** Use of this interface is not recommended.
2399 ** Definition: A <b>result table</b> is memory data structure created by the
2400 ** [sqlite3_get_table()] interface. A result table records the
2401 ** complete query results from one or more queries.
2403 ** The table conceptually has a number of rows and columns. But
2404 ** these numbers are not part of the result table itself. These
2405 ** numbers are obtained separately. Let N be the number of rows
2406 ** and M be the number of columns.
2408 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2409 ** There are (N+1)*M elements in the array. The first M pointers point
2410 ** to zero-terminated strings that contain the names of the columns.
2411 ** The remaining entries all point to query results. NULL values result
2412 ** in NULL pointers. All other values are in their UTF-8 zero-terminated
2413 ** string representation as returned by [sqlite3_column_text()].
2415 ** A result table might consist of one or more memory allocations.
2416 ** It is not safe to pass a result table directly to [sqlite3_free()].
2417 ** A result table should be deallocated using [sqlite3_free_table()].
2419 ** ^(As an example of the result table format, suppose a query result
2422 ** <blockquote><pre>
2424 ** -----------------------
2428 ** </pre></blockquote>
2430 ** There are two column (M==2) and three rows (N==3). Thus the
2431 ** result table has 8 entries. Suppose the result table is stored
2432 ** in an array names azResult. Then azResult holds this content:
2434 ** <blockquote><pre>
2435 ** azResult[0] = "Name";
2436 ** azResult[1] = "Age";
2437 ** azResult[2] = "Alice";
2438 ** azResult[3] = "43";
2439 ** azResult[4] = "Bob";
2440 ** azResult[5] = "28";
2441 ** azResult[6] = "Cindy";
2442 ** azResult[7] = "21";
2443 ** </pre></blockquote>)^
2445 ** ^The sqlite3_get_table() function evaluates one or more
2446 ** semicolon-separated SQL statements in the zero-terminated UTF-8
2447 ** string of its 2nd parameter and returns a result table to the
2448 ** pointer given in its 3rd parameter.
2450 ** After the application has finished with the result from sqlite3_get_table(),
2451 ** it must pass the result table pointer to sqlite3_free_table() in order to
2452 ** release the memory that was malloced. Because of the way the
2453 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2454 ** function must not try to call [sqlite3_free()] directly. Only
2455 ** [sqlite3_free_table()] is able to release the memory properly and safely.
2457 ** The sqlite3_get_table() interface is implemented as a wrapper around
2458 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
2459 ** to any internal data structures of SQLite. It uses only the public
2460 ** interface defined here. As a consequence, errors that occur in the
2461 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2462 ** reflected in subsequent calls to [sqlite3_errcode()] or
2463 ** [sqlite3_errmsg()].
2465 SQLITE_API int sqlite3_get_table(
2466 sqlite3 *db, /* An open database */
2467 const char *zSql, /* SQL to be evaluated */
2468 char ***pazResult, /* Results of the query */
2469 int *pnRow, /* Number of result rows written here */
2470 int *pnColumn, /* Number of result columns written here */
2471 char **pzErrmsg /* Error msg written here */
2473 SQLITE_API void sqlite3_free_table(char **result);
2476 ** CAPI3REF: Formatted String Printing Functions
2478 ** These routines are work-alikes of the "printf()" family of functions
2479 ** from the standard C library.
2480 ** These routines understand most of the common K&R formatting options,
2481 ** plus some additional non-standard formats, detailed below.
2482 ** Note that some of the more obscure formatting options from recent
2483 ** C-library standards are omitted from this implementation.
2485 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2486 ** results into memory obtained from [sqlite3_malloc()].
2487 ** The strings returned by these two routines should be
2488 ** released by [sqlite3_free()]. ^Both routines return a
2489 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2490 ** memory to hold the resulting string.
2492 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2493 ** the standard C library. The result is written into the
2494 ** buffer supplied as the second parameter whose size is given by
2495 ** the first parameter. Note that the order of the
2496 ** first two parameters is reversed from snprintf().)^ This is an
2497 ** historical accident that cannot be fixed without breaking
2498 ** backwards compatibility. ^(Note also that sqlite3_snprintf()
2499 ** returns a pointer to its buffer instead of the number of
2500 ** characters actually written into the buffer.)^ We admit that
2501 ** the number of characters written would be a more useful return
2502 ** value but we cannot change the implementation of sqlite3_snprintf()
2503 ** now without breaking compatibility.
2505 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2506 ** guarantees that the buffer is always zero-terminated. ^The first
2507 ** parameter "n" is the total size of the buffer, including space for
2508 ** the zero terminator. So the longest string that can be completely
2509 ** written will be n-1 characters.
2511 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2513 ** These routines all implement some additional formatting
2514 ** options that are useful for constructing SQL statements.
2515 ** All of the usual printf() formatting options apply. In addition, there
2516 ** is are "%q", "%Q", "%w" and "%z" options.
2518 ** ^(The %q option works like %s in that it substitutes a nul-terminated
2519 ** string from the argument list. But %q also doubles every '\'' character.
2520 ** %q is designed for use inside a string literal.)^ By doubling each '\''
2521 ** character it escapes that character and allows it to be inserted into
2524 ** For example, assume the string variable zText contains text as follows:
2526 ** <blockquote><pre>
2527 ** char *zText = "It's a happy day!";
2528 ** </pre></blockquote>
2530 ** One can use this text in an SQL statement as follows:
2532 ** <blockquote><pre>
2533 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2534 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2535 ** sqlite3_free(zSQL);
2536 ** </pre></blockquote>
2538 ** Because the %q format string is used, the '\'' character in zText
2539 ** is escaped and the SQL generated is as follows:
2541 ** <blockquote><pre>
2542 ** INSERT INTO table1 VALUES('It''s a happy day!')
2543 ** </pre></blockquote>
2545 ** This is correct. Had we used %s instead of %q, the generated SQL
2546 ** would have looked like this:
2548 ** <blockquote><pre>
2549 ** INSERT INTO table1 VALUES('It's a happy day!');
2550 ** </pre></blockquote>
2552 ** This second example is an SQL syntax error. As a general rule you should
2553 ** always use %q instead of %s when inserting text into a string literal.
2555 ** ^(The %Q option works like %q except it also adds single quotes around
2556 ** the outside of the total string. Additionally, if the parameter in the
2557 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2558 ** single quotes).)^ So, for example, one could say:
2560 ** <blockquote><pre>
2561 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2562 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2563 ** sqlite3_free(zSQL);
2564 ** </pre></blockquote>
2566 ** The code above will render a correct SQL statement in the zSQL
2567 ** variable even if the zText variable is a NULL pointer.
2569 ** ^(The "%w" formatting option is like "%q" except that it expects to
2570 ** be contained within double-quotes instead of single quotes, and it
2571 ** escapes the double-quote character instead of the single-quote
2572 ** character.)^ The "%w" formatting option is intended for safely inserting
2573 ** table and column names into a constructed SQL statement.
2575 ** ^(The "%z" formatting option works like "%s" but with the
2576 ** addition that after the string has been read and copied into
2577 ** the result, [sqlite3_free()] is called on the input string.)^
2579 SQLITE_API char *sqlite3_mprintf(const char*,...);
2580 SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2581 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2582 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2585 ** CAPI3REF: Memory Allocation Subsystem
2587 ** The SQLite core uses these three routines for all of its own
2588 ** internal memory allocation needs. "Core" in the previous sentence
2589 ** does not include operating-system specific VFS implementation. The
2590 ** Windows VFS uses native malloc() and free() for some operations.
2592 ** ^The sqlite3_malloc() routine returns a pointer to a block
2593 ** of memory at least N bytes in length, where N is the parameter.
2594 ** ^If sqlite3_malloc() is unable to obtain sufficient free
2595 ** memory, it returns a NULL pointer. ^If the parameter N to
2596 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2599 ** ^The sqlite3_malloc64(N) routine works just like
2600 ** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2601 ** of a signed 32-bit integer.
2603 ** ^Calling sqlite3_free() with a pointer previously returned
2604 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2605 ** that it might be reused. ^The sqlite3_free() routine is
2606 ** a no-op if is called with a NULL pointer. Passing a NULL pointer
2607 ** to sqlite3_free() is harmless. After being freed, memory
2608 ** should neither be read nor written. Even reading previously freed
2609 ** memory might result in a segmentation fault or other severe error.
2610 ** Memory corruption, a segmentation fault, or other severe error
2611 ** might result if sqlite3_free() is called with a non-NULL pointer that
2612 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2614 ** ^The sqlite3_realloc(X,N) interface attempts to resize a
2615 ** prior memory allocation X to be at least N bytes.
2616 ** ^If the X parameter to sqlite3_realloc(X,N)
2617 ** is a NULL pointer then its behavior is identical to calling
2618 ** sqlite3_malloc(N).
2619 ** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2620 ** negative then the behavior is exactly the same as calling
2622 ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2623 ** of at least N bytes in size or NULL if insufficient memory is available.
2624 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2625 ** of the prior allocation are copied into the beginning of buffer returned
2626 ** by sqlite3_realloc(X,N) and the prior allocation is freed.
2627 ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2628 ** prior allocation is not freed.
2630 ** ^The sqlite3_realloc64(X,N) interfaces works the same as
2631 ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2632 ** of a 32-bit signed integer.
2634 ** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2635 ** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2636 ** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2637 ** ^The value returned by sqlite3_msize(X) might be larger than the number
2638 ** of bytes requested when X was allocated. ^If X is a NULL pointer then
2639 ** sqlite3_msize(X) returns zero. If X points to something that is not
2640 ** the beginning of memory allocation, or if it points to a formerly
2641 ** valid memory allocation that has now been freed, then the behavior
2642 ** of sqlite3_msize(X) is undefined and possibly harmful.
2644 ** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2645 ** sqlite3_malloc64(), and sqlite3_realloc64()
2646 ** is always aligned to at least an 8 byte boundary, or to a
2647 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2650 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2651 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2652 ** implementation of these routines to be omitted. That capability
2653 ** is no longer provided. Only built-in memory allocators can be used.
2655 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2656 ** the system malloc() and free() directly when converting
2657 ** filenames between the UTF-8 encoding used by SQLite
2658 ** and whatever filename encoding is used by the particular Windows
2659 ** installation. Memory allocation errors were detected, but
2660 ** they were reported back as [SQLITE_CANTOPEN] or
2661 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2663 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2664 ** must be either NULL or else pointers obtained from a prior
2665 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2666 ** not yet been released.
2668 ** The application must not read or write any part of
2669 ** a block of memory after it has been released using
2670 ** [sqlite3_free()] or [sqlite3_realloc()].
2672 SQLITE_API void *sqlite3_malloc(int);
2673 SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
2674 SQLITE_API void *sqlite3_realloc(void*, int);
2675 SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
2676 SQLITE_API void sqlite3_free(void*);
2677 SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
2680 ** CAPI3REF: Memory Allocator Statistics
2682 ** SQLite provides these two interfaces for reporting on the status
2683 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2684 ** routines, which form the built-in memory allocation subsystem.
2686 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2687 ** of memory currently outstanding (malloced but not freed).
2688 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2689 ** value of [sqlite3_memory_used()] since the high-water mark
2690 ** was last reset. ^The values returned by [sqlite3_memory_used()] and
2691 ** [sqlite3_memory_highwater()] include any overhead
2692 ** added by SQLite in its implementation of [sqlite3_malloc()],
2693 ** but not overhead added by the any underlying system library
2694 ** routines that [sqlite3_malloc()] may call.
2696 ** ^The memory high-water mark is reset to the current value of
2697 ** [sqlite3_memory_used()] if and only if the parameter to
2698 ** [sqlite3_memory_highwater()] is true. ^The value returned
2699 ** by [sqlite3_memory_highwater(1)] is the high-water mark
2700 ** prior to the reset.
2702 SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2703 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2706 ** CAPI3REF: Pseudo-Random Number Generator
2708 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2709 ** select random [ROWID | ROWIDs] when inserting new records into a table that
2710 ** already uses the largest possible [ROWID]. The PRNG is also used for
2711 ** the build-in random() and randomblob() SQL functions. This interface allows
2712 ** applications to access the same PRNG for other purposes.
2714 ** ^A call to this routine stores N bytes of randomness into buffer P.
2715 ** ^The P parameter can be a NULL pointer.
2717 ** ^If this routine has not been previously called or if the previous
2718 ** call had N less than one or a NULL pointer for P, then the PRNG is
2719 ** seeded using randomness obtained from the xRandomness method of
2720 ** the default [sqlite3_vfs] object.
2721 ** ^If the previous call to this routine had an N of 1 or more and a
2722 ** non-NULL P then the pseudo-randomness is generated
2723 ** internally and without recourse to the [sqlite3_vfs] xRandomness
2726 SQLITE_API void sqlite3_randomness(int N, void *P);
2729 ** CAPI3REF: Compile-Time Authorization Callbacks
2731 ** KEYWORDS: {authorizer callback}
2733 ** ^This routine registers an authorizer callback with a particular
2734 ** [database connection], supplied in the first argument.
2735 ** ^The authorizer callback is invoked as SQL statements are being compiled
2736 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2737 ** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
2738 ** and [sqlite3_prepare16_v3()]. ^At various
2739 ** points during the compilation process, as logic is being created
2740 ** to perform various actions, the authorizer callback is invoked to
2741 ** see if those actions are allowed. ^The authorizer callback should
2742 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2743 ** specific action but allow the SQL statement to continue to be
2744 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2745 ** rejected with an error. ^If the authorizer callback returns
2746 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2747 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2748 ** the authorizer will fail with an error message.
2750 ** When the callback returns [SQLITE_OK], that means the operation
2751 ** requested is ok. ^When the callback returns [SQLITE_DENY], the
2752 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2753 ** authorizer will fail with an error message explaining that
2754 ** access is denied.
2756 ** ^The first parameter to the authorizer callback is a copy of the third
2757 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2758 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2759 ** the particular action to be authorized. ^The third through sixth parameters
2760 ** to the callback are either NULL pointers or zero-terminated strings
2761 ** that contain additional details about the action to be authorized.
2762 ** Applications must always be prepared to encounter a NULL pointer in any
2763 ** of the third through the sixth parameters of the authorization callback.
2765 ** ^If the action code is [SQLITE_READ]
2766 ** and the callback returns [SQLITE_IGNORE] then the
2767 ** [prepared statement] statement is constructed to substitute
2768 ** a NULL value in place of the table column that would have
2769 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2770 ** return can be used to deny an untrusted user access to individual
2771 ** columns of a table.
2772 ** ^When a table is referenced by a [SELECT] but no column values are
2773 ** extracted from that table (for example in a query like
2774 ** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
2775 ** is invoked once for that table with a column name that is an empty string.
2776 ** ^If the action code is [SQLITE_DELETE] and the callback returns
2777 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2778 ** [truncate optimization] is disabled and all rows are deleted individually.
2780 ** An authorizer is used when [sqlite3_prepare | preparing]
2781 ** SQL statements from an untrusted source, to ensure that the SQL statements
2782 ** do not try to access data they are not allowed to see, or that they do not
2783 ** try to execute malicious statements that damage the database. For
2784 ** example, an application may allow a user to enter arbitrary
2785 ** SQL queries for evaluation by a database. But the application does
2786 ** not want the user to be able to make arbitrary changes to the
2787 ** database. An authorizer could then be put in place while the
2788 ** user-entered SQL is being [sqlite3_prepare | prepared] that
2789 ** disallows everything except [SELECT] statements.
2791 ** Applications that need to process SQL from untrusted sources
2792 ** might also consider lowering resource limits using [sqlite3_limit()]
2793 ** and limiting database size using the [max_page_count] [PRAGMA]
2794 ** in addition to using an authorizer.
2796 ** ^(Only a single authorizer can be in place on a database connection
2797 ** at a time. Each call to sqlite3_set_authorizer overrides the
2798 ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2799 ** The authorizer is disabled by default.
2801 ** The authorizer callback must not do anything that will modify
2802 ** the database connection that invoked the authorizer callback.
2803 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2804 ** database connections for the meaning of "modify" in this paragraph.
2806 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2807 ** statement might be re-prepared during [sqlite3_step()] due to a
2808 ** schema change. Hence, the application should ensure that the
2809 ** correct authorizer callback remains in place during the [sqlite3_step()].
2811 ** ^Note that the authorizer callback is invoked only during
2812 ** [sqlite3_prepare()] or its variants. Authorization is not
2813 ** performed during statement evaluation in [sqlite3_step()], unless
2814 ** as stated in the previous paragraph, sqlite3_step() invokes
2815 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2817 SQLITE_API int sqlite3_set_authorizer(
2819 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2824 ** CAPI3REF: Authorizer Return Codes
2826 ** The [sqlite3_set_authorizer | authorizer callback function] must
2827 ** return either [SQLITE_OK] or one of these two constants in order
2828 ** to signal SQLite whether or not the action is permitted. See the
2829 ** [sqlite3_set_authorizer | authorizer documentation] for additional
2832 ** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2833 ** returned from the [sqlite3_vtab_on_conflict()] interface.
2835 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */
2836 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
2839 ** CAPI3REF: Authorizer Action Codes
2841 ** The [sqlite3_set_authorizer()] interface registers a callback function
2842 ** that is invoked to authorize certain SQL statement actions. The
2843 ** second parameter to the callback is an integer code that specifies
2844 ** what action is being authorized. These are the integer action codes that
2845 ** the authorizer callback may be passed.
2847 ** These action code values signify what kind of operation is to be
2848 ** authorized. The 3rd and 4th parameters to the authorization
2849 ** callback function will be parameters or NULL depending on which of these
2850 ** codes is used as the second parameter. ^(The 5th parameter to the
2851 ** authorizer callback is the name of the database ("main", "temp",
2852 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2853 ** is the name of the inner-most trigger or view that is responsible for
2854 ** the access attempt or NULL if this access attempt is directly from
2855 ** top-level SQL code.
2857 /******************************************* 3rd ************ 4th ***********/
2858 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
2859 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
2860 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
2861 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
2862 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
2863 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
2864 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2865 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2866 #define SQLITE_DELETE 9 /* Table Name NULL */
2867 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2868 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2869 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2870 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2871 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2872 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2873 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2874 #define SQLITE_DROP_VIEW 17 /* View Name NULL */
2875 #define SQLITE_INSERT 18 /* Table Name NULL */
2876 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2877 #define SQLITE_READ 20 /* Table Name Column Name */
2878 #define SQLITE_SELECT 21 /* NULL NULL */
2879 #define SQLITE_TRANSACTION 22 /* Operation NULL */
2880 #define SQLITE_UPDATE 23 /* Table Name Column Name */
2881 #define SQLITE_ATTACH 24 /* Filename NULL */
2882 #define SQLITE_DETACH 25 /* Database Name NULL */
2883 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2884 #define SQLITE_REINDEX 27 /* Index Name NULL */
2885 #define SQLITE_ANALYZE 28 /* Table Name NULL */
2886 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2887 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2888 #define SQLITE_FUNCTION 31 /* NULL Function Name */
2889 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2890 #define SQLITE_COPY 0 /* No longer used */
2891 #define SQLITE_RECURSIVE 33 /* NULL NULL */
2894 ** CAPI3REF: Tracing And Profiling Functions
2897 ** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
2898 ** instead of the routines described here.
2900 ** These routines register callback functions that can be used for
2901 ** tracing and profiling the execution of SQL statements.
2903 ** ^The callback function registered by sqlite3_trace() is invoked at
2904 ** various times when an SQL statement is being run by [sqlite3_step()].
2905 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2906 ** SQL statement text as the statement first begins executing.
2907 ** ^(Additional sqlite3_trace() callbacks might occur
2908 ** as each triggered subprogram is entered. The callbacks for triggers
2909 ** contain a UTF-8 SQL comment that identifies the trigger.)^
2911 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2912 ** the length of [bound parameter] expansion in the output of sqlite3_trace().
2914 ** ^The callback function registered by sqlite3_profile() is invoked
2915 ** as each SQL statement finishes. ^The profile callback contains
2916 ** the original statement text and an estimate of wall-clock time
2917 ** of how long that statement took to run. ^The profile callback
2918 ** time is in units of nanoseconds, however the current implementation
2919 ** is only capable of millisecond resolution so the six least significant
2920 ** digits in the time are meaningless. Future versions of SQLite
2921 ** might provide greater resolution on the profiler callback. The
2922 ** sqlite3_profile() function is considered experimental and is
2923 ** subject to change in future versions of SQLite.
2925 SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
2926 void(*xTrace)(void*,const char*), void*);
2927 SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
2928 void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2931 ** CAPI3REF: SQL Trace Event Codes
2932 ** KEYWORDS: SQLITE_TRACE
2934 ** These constants identify classes of events that can be monitored
2935 ** using the [sqlite3_trace_v2()] tracing logic. The third argument
2936 ** to [sqlite3_trace_v2()] is an OR-ed combination of one or more of
2937 ** the following constants. ^The first argument to the trace callback
2938 ** is one of the following constants.
2940 ** New tracing constants may be added in future releases.
2942 ** ^A trace callback has four arguments: xCallback(T,C,P,X).
2943 ** ^The T argument is one of the integer type codes above.
2944 ** ^The C argument is a copy of the context pointer passed in as the
2945 ** fourth argument to [sqlite3_trace_v2()].
2946 ** The P and X arguments are pointers whose meanings depend on T.
2949 ** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
2950 ** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
2951 ** first begins running and possibly at other times during the
2952 ** execution of the prepared statement, such as at the start of each
2953 ** trigger subprogram. ^The P argument is a pointer to the
2954 ** [prepared statement]. ^The X argument is a pointer to a string which
2955 ** is the unexpanded SQL text of the prepared statement or an SQL comment
2956 ** that indicates the invocation of a trigger. ^The callback can compute
2957 ** the same text that would have been returned by the legacy [sqlite3_trace()]
2958 ** interface by using the X argument when X begins with "--" and invoking
2959 ** [sqlite3_expanded_sql(P)] otherwise.
2961 ** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
2962 ** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
2963 ** information as is provided by the [sqlite3_profile()] callback.
2964 ** ^The P argument is a pointer to the [prepared statement] and the
2965 ** X argument points to a 64-bit integer which is the estimated of
2966 ** the number of nanosecond that the prepared statement took to run.
2967 ** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
2969 ** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
2970 ** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
2971 ** statement generates a single row of result.
2972 ** ^The P argument is a pointer to the [prepared statement] and the
2973 ** X argument is unused.
2975 ** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
2976 ** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
2977 ** connection closes.
2978 ** ^The P argument is a pointer to the [database connection] object
2979 ** and the X argument is unused.
2982 #define SQLITE_TRACE_STMT 0x01
2983 #define SQLITE_TRACE_PROFILE 0x02
2984 #define SQLITE_TRACE_ROW 0x04
2985 #define SQLITE_TRACE_CLOSE 0x08
2988 ** CAPI3REF: SQL Trace Hook
2991 ** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
2992 ** function X against [database connection] D, using property mask M
2993 ** and context pointer P. ^If the X callback is
2994 ** NULL or if the M mask is zero, then tracing is disabled. The
2995 ** M argument should be the bitwise OR-ed combination of
2996 ** zero or more [SQLITE_TRACE] constants.
2998 ** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides
2999 ** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2().
3001 ** ^The X callback is invoked whenever any of the events identified by
3002 ** mask M occur. ^The integer return value from the callback is currently
3003 ** ignored, though this may change in future releases. Callback
3004 ** implementations should return zero to ensure future compatibility.
3006 ** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
3007 ** ^The T argument is one of the [SQLITE_TRACE]
3008 ** constants to indicate why the callback was invoked.
3009 ** ^The C argument is a copy of the context pointer.
3010 ** The P and X arguments are pointers whose meanings depend on T.
3012 ** The sqlite3_trace_v2() interface is intended to replace the legacy
3013 ** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
3016 SQLITE_API int sqlite3_trace_v2(
3019 int(*xCallback)(unsigned,void*,void*,void*),
3024 ** CAPI3REF: Query Progress Callbacks
3027 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
3028 ** function X to be invoked periodically during long running calls to
3029 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
3030 ** database connection D. An example use for this
3031 ** interface is to keep a GUI updated during a large query.
3033 ** ^The parameter P is passed through as the only parameter to the
3034 ** callback function X. ^The parameter N is the approximate number of
3035 ** [virtual machine instructions] that are evaluated between successive
3036 ** invocations of the callback X. ^If N is less than one then the progress
3037 ** handler is disabled.
3039 ** ^Only a single progress handler may be defined at one time per
3040 ** [database connection]; setting a new progress handler cancels the
3041 ** old one. ^Setting parameter X to NULL disables the progress handler.
3042 ** ^The progress handler is also disabled by setting N to a value less
3045 ** ^If the progress callback returns non-zero, the operation is
3046 ** interrupted. This feature can be used to implement a
3047 ** "Cancel" button on a GUI progress dialog box.
3049 ** The progress handler callback must not do anything that will modify
3050 ** the database connection that invoked the progress handler.
3051 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3052 ** database connections for the meaning of "modify" in this paragraph.
3055 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
3058 ** CAPI3REF: Opening A New Database Connection
3059 ** CONSTRUCTOR: sqlite3
3061 ** ^These routines open an SQLite database file as specified by the
3062 ** filename argument. ^The filename argument is interpreted as UTF-8 for
3063 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
3064 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
3065 ** returned in *ppDb, even if an error occurs. The only exception is that
3066 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
3067 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
3068 ** object.)^ ^(If the database is opened (and/or created) successfully, then
3069 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
3070 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
3071 ** an English language description of the error following a failure of any
3072 ** of the sqlite3_open() routines.
3074 ** ^The default encoding will be UTF-8 for databases created using
3075 ** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases
3076 ** created using sqlite3_open16() will be UTF-16 in the native byte order.
3078 ** Whether or not an error occurs when it is opened, resources
3079 ** associated with the [database connection] handle should be released by
3080 ** passing it to [sqlite3_close()] when it is no longer required.
3082 ** The sqlite3_open_v2() interface works like sqlite3_open()
3083 ** except that it accepts two additional parameters for additional control
3084 ** over the new database connection. ^(The flags parameter to
3085 ** sqlite3_open_v2() can take one of
3086 ** the following three values, optionally combined with the
3087 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
3088 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
3091 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
3092 ** <dd>The database is opened in read-only mode. If the database does not
3093 ** already exist, an error is returned.</dd>)^
3095 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
3096 ** <dd>The database is opened for reading and writing if possible, or reading
3097 ** only if the file is write protected by the operating system. In either
3098 ** case the database must already exist, otherwise an error is returned.</dd>)^
3100 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
3101 ** <dd>The database is opened for reading and writing, and is created if
3102 ** it does not already exist. This is the behavior that is always used for
3103 ** sqlite3_open() and sqlite3_open16().</dd>)^
3106 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
3107 ** combinations shown above optionally combined with other
3108 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
3109 ** then the behavior is undefined.
3111 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
3112 ** opens in the multi-thread [threading mode] as long as the single-thread
3113 ** mode has not been set at compile-time or start-time. ^If the
3114 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
3115 ** in the serialized [threading mode] unless single-thread was
3116 ** previously selected at compile-time or start-time.
3117 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
3118 ** eligible to use [shared cache mode], regardless of whether or not shared
3119 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
3120 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
3121 ** participate in [shared cache mode] even if it is enabled.
3123 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
3124 ** [sqlite3_vfs] object that defines the operating system interface that
3125 ** the new database connection should use. ^If the fourth parameter is
3126 ** a NULL pointer then the default [sqlite3_vfs] object is used.
3128 ** ^If the filename is ":memory:", then a private, temporary in-memory database
3129 ** is created for the connection. ^This in-memory database will vanish when
3130 ** the database connection is closed. Future versions of SQLite might
3131 ** make use of additional special filenames that begin with the ":" character.
3132 ** It is recommended that when a database filename actually does begin with
3133 ** a ":" character you should prefix the filename with a pathname such as
3134 ** "./" to avoid ambiguity.
3136 ** ^If the filename is an empty string, then a private, temporary
3137 ** on-disk database will be created. ^This private database will be
3138 ** automatically deleted as soon as the database connection is closed.
3140 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
3142 ** ^If [URI filename] interpretation is enabled, and the filename argument
3143 ** begins with "file:", then the filename is interpreted as a URI. ^URI
3144 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
3145 ** set in the third argument to sqlite3_open_v2(), or if it has
3146 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
3147 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
3148 ** URI filename interpretation is turned off
3149 ** by default, but future releases of SQLite might enable URI filename
3150 ** interpretation by default. See "[URI filenames]" for additional
3153 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
3154 ** authority, then it must be either an empty string or the string
3155 ** "localhost". ^If the authority is not an empty string or "localhost", an
3156 ** error is returned to the caller. ^The fragment component of a URI, if
3157 ** present, is ignored.
3159 ** ^SQLite uses the path component of the URI as the name of the disk file
3160 ** which contains the database. ^If the path begins with a '/' character,
3161 ** then it is interpreted as an absolute path. ^If the path does not begin
3162 ** with a '/' (meaning that the authority section is omitted from the URI)
3163 ** then the path is interpreted as a relative path.
3164 ** ^(On windows, the first component of an absolute path
3165 ** is a drive specification (e.g. "C:").)^
3167 ** [[core URI query parameters]]
3168 ** The query component of a URI may contain parameters that are interpreted
3169 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
3170 ** SQLite and its built-in [VFSes] interpret the
3171 ** following query parameters:
3174 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
3175 ** a VFS object that provides the operating system interface that should
3176 ** be used to access the database file on disk. ^If this option is set to
3177 ** an empty string the default VFS object is used. ^Specifying an unknown
3178 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
3179 ** present, then the VFS specified by the option takes precedence over
3180 ** the value passed as the fourth parameter to sqlite3_open_v2().
3182 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
3183 ** "rwc", or "memory". Attempting to set it to any other value is
3185 ** ^If "ro" is specified, then the database is opened for read-only
3186 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
3187 ** third argument to sqlite3_open_v2(). ^If the mode option is set to
3188 ** "rw", then the database is opened for read-write (but not create)
3189 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
3190 ** been set. ^Value "rwc" is equivalent to setting both
3191 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
3192 ** set to "memory" then a pure [in-memory database] that never reads
3193 ** or writes from disk is used. ^It is an error to specify a value for
3194 ** the mode parameter that is less restrictive than that specified by
3195 ** the flags passed in the third parameter to sqlite3_open_v2().
3197 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
3198 ** "private". ^Setting it to "shared" is equivalent to setting the
3199 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
3200 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
3201 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
3202 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
3203 ** a URI filename, its value overrides any behavior requested by setting
3204 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
3206 ** <li> <b>psow</b>: ^The psow parameter indicates whether or not the
3207 ** [powersafe overwrite] property does or does not apply to the
3208 ** storage media on which the database file resides.
3210 ** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
3211 ** which if set disables file locking in rollback journal modes. This
3212 ** is useful for accessing a database on a filesystem that does not
3213 ** support locking. Caution: Database corruption might result if two
3214 ** or more processes write to the same database and any one of those
3215 ** processes uses nolock=1.
3217 ** <li> <b>immutable</b>: ^The immutable parameter is a boolean query
3218 ** parameter that indicates that the database file is stored on
3219 ** read-only media. ^When immutable is set, SQLite assumes that the
3220 ** database file cannot be changed, even by a process with higher
3221 ** privilege, and so the database is opened read-only and all locking
3222 ** and change detection is disabled. Caution: Setting the immutable
3223 ** property on a database file that does in fact change can result
3224 ** in incorrect query results and/or [SQLITE_CORRUPT] errors.
3225 ** See also: [SQLITE_IOCAP_IMMUTABLE].
3229 ** ^Specifying an unknown parameter in the query component of a URI is not an
3230 ** error. Future versions of SQLite might understand additional query
3231 ** parameters. See "[query parameters with special meaning to SQLite]" for
3232 ** additional information.
3234 ** [[URI filename examples]] <h3>URI filename examples</h3>
3236 ** <table border="1" align=center cellpadding=5>
3237 ** <tr><th> URI filenames <th> Results
3238 ** <tr><td> file:data.db <td>
3239 ** Open the file "data.db" in the current directory.
3240 ** <tr><td> file:/home/fred/data.db<br>
3241 ** file:///home/fred/data.db <br>
3242 ** file://localhost/home/fred/data.db <br> <td>
3243 ** Open the database file "/home/fred/data.db".
3244 ** <tr><td> file://darkstar/home/fred/data.db <td>
3245 ** An error. "darkstar" is not a recognized authority.
3246 ** <tr><td style="white-space:nowrap">
3247 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
3248 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive
3249 ** C:. Note that the %20 escaping in this example is not strictly
3250 ** necessary - space characters can be used literally
3251 ** in URI filenames.
3252 ** <tr><td> file:data.db?mode=ro&cache=private <td>
3253 ** Open file "data.db" in the current directory for read-only access.
3254 ** Regardless of whether or not shared-cache mode is enabled by
3255 ** default, use a private cache.
3256 ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
3257 ** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
3258 ** that uses dot-files in place of posix advisory locking.
3259 ** <tr><td> file:data.db?mode=readonly <td>
3260 ** An error. "readonly" is not a valid option for the "mode" parameter.
3263 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
3264 ** query components of a URI. A hexadecimal escape sequence consists of a
3265 ** percent sign - "%" - followed by exactly two hexadecimal digits
3266 ** specifying an octet value. ^Before the path or query components of a
3267 ** URI filename are interpreted, they are encoded using UTF-8 and all
3268 ** hexadecimal escape sequences replaced by a single byte containing the
3269 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
3270 ** the results are undefined.
3272 ** <b>Note to Windows users:</b> The encoding used for the filename argument
3273 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
3274 ** codepage is currently defined. Filenames containing international
3275 ** characters must be converted to UTF-8 prior to passing them into
3276 ** sqlite3_open() or sqlite3_open_v2().
3278 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
3279 ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
3280 ** features that require the use of temporary files may fail.
3282 ** See also: [sqlite3_temp_directory]
3284 SQLITE_API int sqlite3_open(
3285 const char *filename, /* Database filename (UTF-8) */
3286 sqlite3 **ppDb /* OUT: SQLite db handle */
3288 SQLITE_API int sqlite3_open16(
3289 const void *filename, /* Database filename (UTF-16) */
3290 sqlite3 **ppDb /* OUT: SQLite db handle */
3292 SQLITE_API int sqlite3_open_v2(
3293 const char *filename, /* Database filename (UTF-8) */
3294 sqlite3 **ppDb, /* OUT: SQLite db handle */
3295 int flags, /* Flags */
3296 const char *zVfs /* Name of VFS module to use */
3300 ** CAPI3REF: Obtain Values For URI Parameters
3302 ** These are utility routines, useful to VFS implementations, that check
3303 ** to see if a database file was a URI that contained a specific query
3304 ** parameter, and if so obtains the value of that query parameter.
3306 ** If F is the database filename pointer passed into the xOpen() method of
3307 ** a VFS implementation when the flags parameter to xOpen() has one or
3308 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
3309 ** P is the name of the query parameter, then
3310 ** sqlite3_uri_parameter(F,P) returns the value of the P
3311 ** parameter if it exists or a NULL pointer if P does not appear as a
3312 ** query parameter on F. If P is a query parameter of F
3313 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3314 ** a pointer to an empty string.
3316 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3317 ** parameter and returns true (1) or false (0) according to the value
3318 ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3319 ** value of query parameter P is one of "yes", "true", or "on" in any
3320 ** case or if the value begins with a non-zero number. The
3321 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3322 ** query parameter P is one of "no", "false", or "off" in any case or
3323 ** if the value begins with a numeric zero. If P is not a query
3324 ** parameter on F or if the value of P is does not match any of the
3325 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3327 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3328 ** 64-bit signed integer and returns that integer, or D if P does not
3329 ** exist. If the value of P is something other than an integer, then
3330 ** zero is returned.
3332 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3333 ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
3334 ** is not a database file pathname pointer that SQLite passed into the xOpen
3335 ** VFS method, then the behavior of this routine is undefined and probably
3338 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3339 SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3340 SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3344 ** CAPI3REF: Error Codes And Messages
3347 ** ^If the most recent sqlite3_* API call associated with
3348 ** [database connection] D failed, then the sqlite3_errcode(D) interface
3349 ** returns the numeric [result code] or [extended result code] for that
3351 ** If the most recent API call was successful,
3352 ** then the return value from sqlite3_errcode() is undefined.
3353 ** ^The sqlite3_extended_errcode()
3354 ** interface is the same except that it always returns the
3355 ** [extended result code] even when extended result codes are
3358 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3359 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
3360 ** ^(Memory to hold the error message string is managed internally.
3361 ** The application does not need to worry about freeing the result.
3362 ** However, the error string might be overwritten or deallocated by
3363 ** subsequent calls to other SQLite interface functions.)^
3365 ** ^The sqlite3_errstr() interface returns the English-language text
3366 ** that describes the [result code], as UTF-8.
3367 ** ^(Memory to hold the error message string is managed internally
3368 ** and must not be freed by the application)^.
3370 ** When the serialized [threading mode] is in use, it might be the
3371 ** case that a second error occurs on a separate thread in between
3372 ** the time of the first error and the call to these interfaces.
3373 ** When that happens, the second error will be reported since these
3374 ** interfaces always report the most recent result. To avoid
3375 ** this, each thread can obtain exclusive use of the [database connection] D
3376 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3377 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3378 ** all calls to the interfaces listed here are completed.
3380 ** If an interface fails with SQLITE_MISUSE, that means the interface
3381 ** was invoked incorrectly by the application. In that case, the
3382 ** error code and message may or may not be set.
3384 SQLITE_API int sqlite3_errcode(sqlite3 *db);
3385 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
3386 SQLITE_API const char *sqlite3_errmsg(sqlite3*);
3387 SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
3388 SQLITE_API const char *sqlite3_errstr(int);
3391 ** CAPI3REF: Prepared Statement Object
3392 ** KEYWORDS: {prepared statement} {prepared statements}
3394 ** An instance of this object represents a single SQL statement that
3395 ** has been compiled into binary form and is ready to be evaluated.
3397 ** Think of each SQL statement as a separate computer program. The
3398 ** original SQL text is source code. A prepared statement object
3399 ** is the compiled object code. All SQL must be converted into a
3400 ** prepared statement before it can be run.
3402 ** The life-cycle of a prepared statement object usually goes like this:
3405 ** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
3406 ** <li> Bind values to [parameters] using the sqlite3_bind_*()
3408 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3409 ** <li> Reset the prepared statement using [sqlite3_reset()] then go back
3410 ** to step 2. Do this zero or more times.
3411 ** <li> Destroy the object using [sqlite3_finalize()].
3414 typedef struct sqlite3_stmt sqlite3_stmt;
3417 ** CAPI3REF: Run-time Limits
3420 ** ^(This interface allows the size of various constructs to be limited
3421 ** on a connection by connection basis. The first parameter is the
3422 ** [database connection] whose limit is to be set or queried. The
3423 ** second parameter is one of the [limit categories] that define a
3424 ** class of constructs to be size limited. The third parameter is the
3425 ** new limit for that construct.)^
3427 ** ^If the new limit is a negative number, the limit is unchanged.
3428 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3429 ** [limits | hard upper bound]
3430 ** set at compile-time by a C preprocessor macro called
3431 ** [limits | SQLITE_MAX_<i>NAME</i>].
3432 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3433 ** ^Attempts to increase a limit above its hard upper bound are
3434 ** silently truncated to the hard upper bound.
3436 ** ^Regardless of whether or not the limit was changed, the
3437 ** [sqlite3_limit()] interface returns the prior value of the limit.
3438 ** ^Hence, to find the current value of a limit without changing it,
3439 ** simply invoke this interface with the third parameter set to -1.
3441 ** Run-time limits are intended for use in applications that manage
3442 ** both their own internal database and also databases that are controlled
3443 ** by untrusted external sources. An example application might be a
3444 ** web browser that has its own databases for storing history and
3445 ** separate databases controlled by JavaScript applications downloaded
3446 ** off the Internet. The internal databases can be given the
3447 ** large, default limits. Databases managed by external sources can
3448 ** be given much smaller limits designed to prevent a denial of service
3449 ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
3450 ** interface to further control untrusted SQL. The size of the database
3451 ** created by an untrusted script can be contained using the
3452 ** [max_page_count] [PRAGMA].
3454 ** New run-time limit categories may be added in future releases.
3456 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
3459 ** CAPI3REF: Run-Time Limit Categories
3460 ** KEYWORDS: {limit category} {*limit categories}
3462 ** These constants define various performance limits
3463 ** that can be lowered at run-time using [sqlite3_limit()].
3464 ** The synopsis of the meanings of the various limits is shown below.
3465 ** Additional information is available at [limits | Limits in SQLite].
3468 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3469 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3471 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3472 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3474 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3475 ** <dd>The maximum number of columns in a table definition or in the
3476 ** result set of a [SELECT] or the maximum number of columns in an index
3477 ** or in an ORDER BY or GROUP BY clause.</dd>)^
3479 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3480 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3482 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3483 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3485 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3486 ** <dd>The maximum number of instructions in a virtual machine program
3487 ** used to implement an SQL statement. If [sqlite3_prepare_v2()] or
3488 ** the equivalent tries to allocate space for more than this many opcodes
3489 ** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
3491 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3492 ** <dd>The maximum number of arguments on a function.</dd>)^
3494 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3495 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3497 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3498 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3499 ** <dd>The maximum length of the pattern argument to the [LIKE] or
3500 ** [GLOB] operators.</dd>)^
3502 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3503 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3504 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3506 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3507 ** <dd>The maximum depth of recursion for triggers.</dd>)^
3509 ** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
3510 ** <dd>The maximum number of auxiliary worker threads that a single
3511 ** [prepared statement] may start.</dd>)^
3514 #define SQLITE_LIMIT_LENGTH 0
3515 #define SQLITE_LIMIT_SQL_LENGTH 1
3516 #define SQLITE_LIMIT_COLUMN 2
3517 #define SQLITE_LIMIT_EXPR_DEPTH 3
3518 #define SQLITE_LIMIT_COMPOUND_SELECT 4
3519 #define SQLITE_LIMIT_VDBE_OP 5
3520 #define SQLITE_LIMIT_FUNCTION_ARG 6
3521 #define SQLITE_LIMIT_ATTACHED 7
3522 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
3523 #define SQLITE_LIMIT_VARIABLE_NUMBER 9
3524 #define SQLITE_LIMIT_TRIGGER_DEPTH 10
3525 #define SQLITE_LIMIT_WORKER_THREADS 11
3528 ** CAPI3REF: Prepare Flags
3530 ** These constants define various flags that can be passed into
3531 ** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
3532 ** [sqlite3_prepare16_v3()] interfaces.
3534 ** New flags may be added in future releases of SQLite.
3537 ** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
3538 ** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
3539 ** that the prepared statement will be retained for a long time and
3540 ** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
3541 ** and [sqlite3_prepare16_v3()] assume that the prepared statement will
3542 ** be used just once or at most a few times and then destroyed using
3543 ** [sqlite3_finalize()] relatively soon. The current implementation acts
3544 ** on this hint by avoiding the use of [lookaside memory] so as not to
3545 ** deplete the limited store of lookaside memory. Future versions of
3546 ** SQLite may act on this hint differently.
3549 #define SQLITE_PREPARE_PERSISTENT 0x01
3552 ** CAPI3REF: Compiling An SQL Statement
3553 ** KEYWORDS: {SQL statement compiler}
3555 ** CONSTRUCTOR: sqlite3_stmt
3557 ** To execute an SQL statement, it must first be compiled into a byte-code
3558 ** program using one of these routines. Or, in other words, these routines
3559 ** are constructors for the [prepared statement] object.
3561 ** The preferred routine to use is [sqlite3_prepare_v2()]. The
3562 ** [sqlite3_prepare()] interface is legacy and should be avoided.
3563 ** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
3564 ** for special purposes.
3566 ** The use of the UTF-8 interfaces is preferred, as SQLite currently
3567 ** does all parsing using UTF-8. The UTF-16 interfaces are provided
3568 ** as a convenience. The UTF-16 interfaces work by converting the
3569 ** input text into UTF-8, then invoking the corresponding UTF-8 interface.
3571 ** The first argument, "db", is a [database connection] obtained from a
3572 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3573 ** [sqlite3_open16()]. The database connection must not have been closed.
3575 ** The second argument, "zSql", is the statement to be compiled, encoded
3576 ** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(),
3577 ** and sqlite3_prepare_v3()
3578 ** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
3579 ** and sqlite3_prepare16_v3() use UTF-16.
3581 ** ^If the nByte argument is negative, then zSql is read up to the
3582 ** first zero terminator. ^If nByte is positive, then it is the
3583 ** number of bytes read from zSql. ^If nByte is zero, then no prepared
3584 ** statement is generated.
3585 ** If the caller knows that the supplied string is nul-terminated, then
3586 ** there is a small performance advantage to passing an nByte parameter that
3587 ** is the number of bytes in the input string <i>including</i>
3588 ** the nul-terminator.
3590 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3591 ** past the end of the first SQL statement in zSql. These routines only
3592 ** compile the first statement in zSql, so *pzTail is left pointing to
3593 ** what remains uncompiled.
3595 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3596 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
3597 ** to NULL. ^If the input text contains no SQL (if the input is an empty
3598 ** string or a comment) then *ppStmt is set to NULL.
3599 ** The calling procedure is responsible for deleting the compiled
3600 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
3601 ** ppStmt may not be NULL.
3603 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3604 ** otherwise an [error code] is returned.
3606 ** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
3607 ** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
3608 ** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
3609 ** are retained for backwards compatibility, but their use is discouraged.
3610 ** ^In the "vX" interfaces, the prepared statement
3611 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
3612 ** original SQL text. This causes the [sqlite3_step()] interface to
3613 ** behave differently in three ways:
3617 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3618 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
3619 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3620 ** retries will occur before sqlite3_step() gives up and returns an error.
3624 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3625 ** [error codes] or [extended error codes]. ^The legacy behavior was that
3626 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3627 ** and the application would have to make a second call to [sqlite3_reset()]
3628 ** in order to find the underlying cause of the problem. With the "v2" prepare
3629 ** interfaces, the underlying reason for the error is returned immediately.
3633 ** ^If the specific value bound to [parameter | host parameter] in the
3634 ** WHERE clause might influence the choice of query plan for a statement,
3635 ** then the statement will be automatically recompiled, as if there had been
3636 ** a schema change, on the first [sqlite3_step()] call following any change
3637 ** to the [sqlite3_bind_text | bindings] of that [parameter].
3638 ** ^The specific value of WHERE-clause [parameter] might influence the
3639 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
3640 ** or [GLOB] operator or if the parameter is compared to an indexed column
3641 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3644 ** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
3645 ** the extra prepFlags parameter, which is a bit array consisting of zero or
3646 ** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The
3647 ** sqlite3_prepare_v2() interface works exactly the same as
3648 ** sqlite3_prepare_v3() with a zero prepFlags parameter.
3651 SQLITE_API int sqlite3_prepare(
3652 sqlite3 *db, /* Database handle */
3653 const char *zSql, /* SQL statement, UTF-8 encoded */
3654 int nByte, /* Maximum length of zSql in bytes. */
3655 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3656 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3658 SQLITE_API int sqlite3_prepare_v2(
3659 sqlite3 *db, /* Database handle */
3660 const char *zSql, /* SQL statement, UTF-8 encoded */
3661 int nByte, /* Maximum length of zSql in bytes. */
3662 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3663 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3665 SQLITE_API int sqlite3_prepare_v3(
3666 sqlite3 *db, /* Database handle */
3667 const char *zSql, /* SQL statement, UTF-8 encoded */
3668 int nByte, /* Maximum length of zSql in bytes. */
3669 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
3670 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3671 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3673 SQLITE_API int sqlite3_prepare16(
3674 sqlite3 *db, /* Database handle */
3675 const void *zSql, /* SQL statement, UTF-16 encoded */
3676 int nByte, /* Maximum length of zSql in bytes. */
3677 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3678 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3680 SQLITE_API int sqlite3_prepare16_v2(
3681 sqlite3 *db, /* Database handle */
3682 const void *zSql, /* SQL statement, UTF-16 encoded */
3683 int nByte, /* Maximum length of zSql in bytes. */
3684 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3685 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3687 SQLITE_API int sqlite3_prepare16_v3(
3688 sqlite3 *db, /* Database handle */
3689 const void *zSql, /* SQL statement, UTF-16 encoded */
3690 int nByte, /* Maximum length of zSql in bytes. */
3691 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
3692 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3693 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3697 ** CAPI3REF: Retrieving Statement SQL
3698 ** METHOD: sqlite3_stmt
3700 ** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
3701 ** SQL text used to create [prepared statement] P if P was
3702 ** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
3703 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
3704 ** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
3705 ** string containing the SQL text of prepared statement P with
3706 ** [bound parameters] expanded.
3708 ** ^(For example, if a prepared statement is created using the SQL
3709 ** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
3710 ** and parameter :xyz is unbound, then sqlite3_sql() will return
3711 ** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
3712 ** will return "SELECT 2345,NULL".)^
3714 ** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
3715 ** is available to hold the result, or if the result would exceed the
3716 ** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
3718 ** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
3719 ** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time
3720 ** option causes sqlite3_expanded_sql() to always return NULL.
3722 ** ^The string returned by sqlite3_sql(P) is managed by SQLite and is
3723 ** automatically freed when the prepared statement is finalized.
3724 ** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
3725 ** is obtained from [sqlite3_malloc()] and must be free by the application
3726 ** by passing it to [sqlite3_free()].
3728 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
3729 SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
3732 ** CAPI3REF: Determine If An SQL Statement Writes The Database
3733 ** METHOD: sqlite3_stmt
3735 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3736 ** and only if the [prepared statement] X makes no direct changes to
3737 ** the content of the database file.
3739 ** Note that [application-defined SQL functions] or
3740 ** [virtual tables] might change the database indirectly as a side effect.
3741 ** ^(For example, if an application defines a function "eval()" that
3742 ** calls [sqlite3_exec()], then the following SQL statement would
3743 ** change the database file through side-effects:
3745 ** <blockquote><pre>
3746 ** SELECT eval('DELETE FROM t1') FROM t2;
3747 ** </pre></blockquote>
3749 ** But because the [SELECT] statement does not change the database file
3750 ** directly, sqlite3_stmt_readonly() would still return true.)^
3752 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3753 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3754 ** since the statements themselves do not actually modify the database but
3755 ** rather they control the timing of when other statements modify the
3756 ** database. ^The [ATTACH] and [DETACH] statements also cause
3757 ** sqlite3_stmt_readonly() to return true since, while those statements
3758 ** change the configuration of a database connection, they do not make
3759 ** changes to the content of the database files on disk.
3760 ** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
3761 ** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
3762 ** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
3763 ** sqlite3_stmt_readonly() returns false for those commands.
3765 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3768 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3769 ** METHOD: sqlite3_stmt
3771 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3772 ** [prepared statement] S has been stepped at least once using
3773 ** [sqlite3_step(S)] but has neither run to completion (returned
3774 ** [SQLITE_DONE] from [sqlite3_step(S)]) nor
3775 ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
3776 ** interface returns false if S is a NULL pointer. If S is not a
3777 ** NULL pointer and is not a pointer to a valid [prepared statement]
3778 ** object, then the behavior is undefined and probably undesirable.
3780 ** This interface can be used in combination [sqlite3_next_stmt()]
3781 ** to locate all prepared statements associated with a database
3782 ** connection that are in need of being reset. This can be used,
3783 ** for example, in diagnostic routines to search for prepared
3784 ** statements that are holding a transaction open.
3786 SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
3789 ** CAPI3REF: Dynamically Typed Value Object
3790 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3792 ** SQLite uses the sqlite3_value object to represent all values
3793 ** that can be stored in a database table. SQLite uses dynamic typing
3794 ** for the values it stores. ^Values stored in sqlite3_value objects
3795 ** can be integers, floating point values, strings, BLOBs, or NULL.
3797 ** An sqlite3_value object may be either "protected" or "unprotected".
3798 ** Some interfaces require a protected sqlite3_value. Other interfaces
3799 ** will accept either a protected or an unprotected sqlite3_value.
3800 ** Every interface that accepts sqlite3_value arguments specifies
3801 ** whether or not it requires a protected sqlite3_value. The
3802 ** [sqlite3_value_dup()] interface can be used to construct a new
3803 ** protected sqlite3_value from an unprotected sqlite3_value.
3805 ** The terms "protected" and "unprotected" refer to whether or not
3806 ** a mutex is held. An internal mutex is held for a protected
3807 ** sqlite3_value object but no mutex is held for an unprotected
3808 ** sqlite3_value object. If SQLite is compiled to be single-threaded
3809 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3810 ** or if SQLite is run in one of reduced mutex modes
3811 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3812 ** then there is no distinction between protected and unprotected
3813 ** sqlite3_value objects and they can be used interchangeably. However,
3814 ** for maximum code portability it is recommended that applications
3815 ** still make the distinction between protected and unprotected
3816 ** sqlite3_value objects even when not strictly required.
3818 ** ^The sqlite3_value objects that are passed as parameters into the
3819 ** implementation of [application-defined SQL functions] are protected.
3820 ** ^The sqlite3_value object returned by
3821 ** [sqlite3_column_value()] is unprotected.
3822 ** Unprotected sqlite3_value objects may only be used as arguments
3823 ** to [sqlite3_result_value()], [sqlite3_bind_value()], and
3824 ** [sqlite3_value_dup()].
3825 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
3826 ** interfaces require protected sqlite3_value objects.
3828 typedef struct sqlite3_value sqlite3_value;
3831 ** CAPI3REF: SQL Function Context Object
3833 ** The context in which an SQL function executes is stored in an
3834 ** sqlite3_context object. ^A pointer to an sqlite3_context object
3835 ** is always first parameter to [application-defined SQL functions].
3836 ** The application-defined SQL function implementation will pass this
3837 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3838 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3839 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3840 ** and/or [sqlite3_set_auxdata()].
3842 typedef struct sqlite3_context sqlite3_context;
3845 ** CAPI3REF: Binding Values To Prepared Statements
3846 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3847 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3848 ** METHOD: sqlite3_stmt
3850 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3851 ** literals may be replaced by a [parameter] that matches one of following
3862 ** In the templates above, NNN represents an integer literal,
3863 ** and VVV represents an alphanumeric identifier.)^ ^The values of these
3864 ** parameters (also called "host parameter names" or "SQL parameters")
3865 ** can be set using the sqlite3_bind_*() routines defined here.
3867 ** ^The first argument to the sqlite3_bind_*() routines is always
3868 ** a pointer to the [sqlite3_stmt] object returned from
3869 ** [sqlite3_prepare_v2()] or its variants.
3871 ** ^The second argument is the index of the SQL parameter to be set.
3872 ** ^The leftmost SQL parameter has an index of 1. ^When the same named
3873 ** SQL parameter is used more than once, second and subsequent
3874 ** occurrences have the same index as the first occurrence.
3875 ** ^The index for named parameters can be looked up using the
3876 ** [sqlite3_bind_parameter_index()] API if desired. ^The index
3877 ** for "?NNN" parameters is the value of NNN.
3878 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
3879 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3881 ** ^The third argument is the value to bind to the parameter.
3882 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3883 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3884 ** is ignored and the end result is the same as sqlite3_bind_null().
3886 ** ^(In those routines that have a fourth argument, its value is the
3887 ** number of bytes in the parameter. To be clear: the value is the
3888 ** number of <u>bytes</u> in the value, not the number of characters.)^
3889 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3890 ** is negative, then the length of the string is
3891 ** the number of bytes up to the first zero terminator.
3892 ** If the fourth parameter to sqlite3_bind_blob() is negative, then
3893 ** the behavior is undefined.
3894 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3895 ** or sqlite3_bind_text16() or sqlite3_bind_text64() then
3896 ** that parameter must be the byte offset
3897 ** where the NUL terminator would occur assuming the string were NUL
3898 ** terminated. If any NUL characters occur at byte offsets less than
3899 ** the value of the fourth parameter then the resulting string value will
3900 ** contain embedded NULs. The result of expressions involving strings
3901 ** with embedded NULs is undefined.
3903 ** ^The fifth argument to the BLOB and string binding interfaces
3904 ** is a destructor used to dispose of the BLOB or
3905 ** string after SQLite has finished with it. ^The destructor is called
3906 ** to dispose of the BLOB or string even if the call to bind API fails.
3907 ** ^If the fifth argument is
3908 ** the special value [SQLITE_STATIC], then SQLite assumes that the
3909 ** information is in static, unmanaged space and does not need to be freed.
3910 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3911 ** SQLite makes its own private copy of the data immediately, before
3912 ** the sqlite3_bind_*() routine returns.
3914 ** ^The sixth argument to sqlite3_bind_text64() must be one of
3915 ** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
3916 ** to specify the encoding of the text in the third parameter. If
3917 ** the sixth argument to sqlite3_bind_text64() is not one of the
3918 ** allowed values shown above, or if the text encoding is different
3919 ** from the encoding specified by the sixth parameter, then the behavior
3922 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3923 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
3924 ** (just an integer to hold its size) while it is being processed.
3925 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
3926 ** content is later written using
3927 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
3928 ** ^A negative value for the zeroblob results in a zero-length BLOB.
3930 ** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
3931 ** [prepared statement] S to have an SQL value of NULL, but to also be
3932 ** associated with the pointer P of type T. ^D is either a NULL pointer or
3933 ** a pointer to a destructor function for P. ^SQLite will invoke the
3934 ** destructor D with a single argument of P when it is finished using
3935 ** P. The T parameter should be a static string, preferably a string
3936 ** literal. The sqlite3_bind_pointer() routine is part of the
3937 ** [pointer passing interface] added for SQLite 3.20.0.
3939 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3940 ** for the [prepared statement] or with a prepared statement for which
3941 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3942 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
3943 ** routine is passed a [prepared statement] that has been finalized, the
3944 ** result is undefined and probably harmful.
3946 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3947 ** ^Unbound parameters are interpreted as NULL.
3949 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3950 ** [error code] if anything goes wrong.
3951 ** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
3952 ** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
3953 ** [SQLITE_MAX_LENGTH].
3954 ** ^[SQLITE_RANGE] is returned if the parameter
3955 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
3957 ** See also: [sqlite3_bind_parameter_count()],
3958 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3960 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3961 SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
3963 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
3964 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
3965 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3966 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
3967 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
3968 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3969 SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
3970 void(*)(void*), unsigned char encoding);
3971 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3972 SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
3973 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3974 SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
3977 ** CAPI3REF: Number Of SQL Parameters
3978 ** METHOD: sqlite3_stmt
3980 ** ^This routine can be used to find the number of [SQL parameters]
3981 ** in a [prepared statement]. SQL parameters are tokens of the
3982 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3983 ** placeholders for values that are [sqlite3_bind_blob | bound]
3984 ** to the parameters at a later time.
3986 ** ^(This routine actually returns the index of the largest (rightmost)
3987 ** parameter. For all forms except ?NNN, this will correspond to the
3988 ** number of unique parameters. If parameters of the ?NNN form are used,
3989 ** there may be gaps in the list.)^
3991 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3992 ** [sqlite3_bind_parameter_name()], and
3993 ** [sqlite3_bind_parameter_index()].
3995 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
3998 ** CAPI3REF: Name Of A Host Parameter
3999 ** METHOD: sqlite3_stmt
4001 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
4002 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
4003 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
4004 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
4006 ** In other words, the initial ":" or "$" or "@" or "?"
4007 ** is included as part of the name.)^
4008 ** ^Parameters of the form "?" without a following integer have no name
4009 ** and are referred to as "nameless" or "anonymous parameters".
4011 ** ^The first host parameter has an index of 1, not 0.
4013 ** ^If the value N is out of range or if the N-th parameter is
4014 ** nameless, then NULL is returned. ^The returned string is
4015 ** always in UTF-8 encoding even if the named parameter was
4016 ** originally specified as UTF-16 in [sqlite3_prepare16()],
4017 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4019 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4020 ** [sqlite3_bind_parameter_count()], and
4021 ** [sqlite3_bind_parameter_index()].
4023 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
4026 ** CAPI3REF: Index Of A Parameter With A Given Name
4027 ** METHOD: sqlite3_stmt
4029 ** ^Return the index of an SQL parameter given its name. ^The
4030 ** index value returned is suitable for use as the second
4031 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
4032 ** is returned if no matching parameter is found. ^The parameter
4033 ** name must be given in UTF-8 even if the original statement
4034 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
4035 ** [sqlite3_prepare16_v3()].
4037 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4038 ** [sqlite3_bind_parameter_count()], and
4039 ** [sqlite3_bind_parameter_name()].
4041 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
4044 ** CAPI3REF: Reset All Bindings On A Prepared Statement
4045 ** METHOD: sqlite3_stmt
4047 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
4048 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
4049 ** ^Use this routine to reset all host parameters to NULL.
4051 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
4054 ** CAPI3REF: Number Of Columns In A Result Set
4055 ** METHOD: sqlite3_stmt
4057 ** ^Return the number of columns in the result set returned by the
4058 ** [prepared statement]. ^If this routine returns 0, that means the
4059 ** [prepared statement] returns no data (for example an [UPDATE]).
4060 ** ^However, just because this routine returns a positive number does not
4061 ** mean that one or more rows of data will be returned. ^A SELECT statement
4062 ** will always have a positive sqlite3_column_count() but depending on the
4063 ** WHERE clause constraints and the table content, it might return no rows.
4065 ** See also: [sqlite3_data_count()]
4067 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
4070 ** CAPI3REF: Column Names In A Result Set
4071 ** METHOD: sqlite3_stmt
4073 ** ^These routines return the name assigned to a particular column
4074 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
4075 ** interface returns a pointer to a zero-terminated UTF-8 string
4076 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
4077 ** UTF-16 string. ^The first parameter is the [prepared statement]
4078 ** that implements the [SELECT] statement. ^The second parameter is the
4079 ** column number. ^The leftmost column is number 0.
4081 ** ^The returned string pointer is valid until either the [prepared statement]
4082 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
4083 ** reprepared by the first call to [sqlite3_step()] for a particular run
4084 ** or until the next call to
4085 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
4087 ** ^If sqlite3_malloc() fails during the processing of either routine
4088 ** (for example during a conversion from UTF-8 to UTF-16) then a
4089 ** NULL pointer is returned.
4091 ** ^The name of a result column is the value of the "AS" clause for
4092 ** that column, if there is an AS clause. If there is no AS clause
4093 ** then the name of the column is unspecified and may change from
4094 ** one release of SQLite to the next.
4096 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
4097 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
4100 ** CAPI3REF: Source Of Data In A Query Result
4101 ** METHOD: sqlite3_stmt
4103 ** ^These routines provide a means to determine the database, table, and
4104 ** table column that is the origin of a particular result column in
4105 ** [SELECT] statement.
4106 ** ^The name of the database or table or column can be returned as
4107 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
4108 ** the database name, the _table_ routines return the table name, and
4109 ** the origin_ routines return the column name.
4110 ** ^The returned string is valid until the [prepared statement] is destroyed
4111 ** using [sqlite3_finalize()] or until the statement is automatically
4112 ** reprepared by the first call to [sqlite3_step()] for a particular run
4113 ** or until the same information is requested
4114 ** again in a different encoding.
4116 ** ^The names returned are the original un-aliased names of the
4117 ** database, table, and column.
4119 ** ^The first argument to these interfaces is a [prepared statement].
4120 ** ^These functions return information about the Nth result column returned by
4121 ** the statement, where N is the second function argument.
4122 ** ^The left-most column is column 0 for these routines.
4124 ** ^If the Nth column returned by the statement is an expression or
4125 ** subquery and is not a column value, then all of these functions return
4126 ** NULL. ^These routine might also return NULL if a memory allocation error
4127 ** occurs. ^Otherwise, they return the name of the attached database, table,
4128 ** or column that query result column was extracted from.
4130 ** ^As with all other SQLite APIs, those whose names end with "16" return
4131 ** UTF-16 encoded strings and the other functions return UTF-8.
4133 ** ^These APIs are only available if the library was compiled with the
4134 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
4136 ** If two or more threads call one or more of these routines against the same
4137 ** prepared statement and column at the same time then the results are
4140 ** If two or more threads call one or more
4141 ** [sqlite3_column_database_name | column metadata interfaces]
4142 ** for the same [prepared statement] and result column
4143 ** at the same time then the results are undefined.
4145 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
4146 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
4147 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
4148 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
4149 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
4150 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
4153 ** CAPI3REF: Declared Datatype Of A Query Result
4154 ** METHOD: sqlite3_stmt
4156 ** ^(The first parameter is a [prepared statement].
4157 ** If this statement is a [SELECT] statement and the Nth column of the
4158 ** returned result set of that [SELECT] is a table column (not an
4159 ** expression or subquery) then the declared type of the table
4160 ** column is returned.)^ ^If the Nth column of the result set is an
4161 ** expression or subquery, then a NULL pointer is returned.
4162 ** ^The returned string is always UTF-8 encoded.
4164 ** ^(For example, given the database schema:
4166 ** CREATE TABLE t1(c1 VARIANT);
4168 ** and the following statement to be compiled:
4170 ** SELECT c1 + 1, c1 FROM t1;
4172 ** this routine would return the string "VARIANT" for the second result
4173 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
4175 ** ^SQLite uses dynamic run-time typing. ^So just because a column
4176 ** is declared to contain a particular type does not mean that the
4177 ** data stored in that column is of the declared type. SQLite is
4178 ** strongly typed, but the typing is dynamic not static. ^Type
4179 ** is associated with individual values, not with the containers
4180 ** used to hold those values.
4182 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
4183 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
4186 ** CAPI3REF: Evaluate An SQL Statement
4187 ** METHOD: sqlite3_stmt
4189 ** After a [prepared statement] has been prepared using any of
4190 ** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
4191 ** or [sqlite3_prepare16_v3()] or one of the legacy
4192 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
4193 ** must be called one or more times to evaluate the statement.
4195 ** The details of the behavior of the sqlite3_step() interface depend
4196 ** on whether the statement was prepared using the newer "vX" interfaces
4197 ** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
4198 ** [sqlite3_prepare16_v2()] or the older legacy
4199 ** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
4200 ** new "vX" interface is recommended for new applications but the legacy
4201 ** interface will continue to be supported.
4203 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
4204 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
4205 ** ^With the "v2" interface, any of the other [result codes] or
4206 ** [extended result codes] might be returned as well.
4208 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
4209 ** database locks it needs to do its job. ^If the statement is a [COMMIT]
4210 ** or occurs outside of an explicit transaction, then you can retry the
4211 ** statement. If the statement is not a [COMMIT] and occurs within an
4212 ** explicit transaction then you should rollback the transaction before
4215 ** ^[SQLITE_DONE] means that the statement has finished executing
4216 ** successfully. sqlite3_step() should not be called again on this virtual
4217 ** machine without first calling [sqlite3_reset()] to reset the virtual
4218 ** machine back to its initial state.
4220 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
4221 ** is returned each time a new row of data is ready for processing by the
4222 ** caller. The values may be accessed using the [column access functions].
4223 ** sqlite3_step() is called again to retrieve the next row of data.
4225 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
4226 ** violation) has occurred. sqlite3_step() should not be called again on
4227 ** the VM. More information may be found by calling [sqlite3_errmsg()].
4228 ** ^With the legacy interface, a more specific error code (for example,
4229 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
4230 ** can be obtained by calling [sqlite3_reset()] on the
4231 ** [prepared statement]. ^In the "v2" interface,
4232 ** the more specific error code is returned directly by sqlite3_step().
4234 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
4235 ** Perhaps it was called on a [prepared statement] that has
4236 ** already been [sqlite3_finalize | finalized] or on one that had
4237 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
4238 ** be the case that the same database connection is being used by two or
4239 ** more threads at the same moment in time.
4241 ** For all versions of SQLite up to and including 3.6.23.1, a call to
4242 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
4243 ** other than [SQLITE_ROW] before any subsequent invocation of
4244 ** sqlite3_step(). Failure to reset the prepared statement using
4245 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
4246 ** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1],
4247 ** sqlite3_step() began
4248 ** calling [sqlite3_reset()] automatically in this circumstance rather
4249 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
4250 ** break because any application that ever receives an SQLITE_MISUSE error
4251 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
4252 ** can be used to restore the legacy behavior.
4254 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
4255 ** API always returns a generic error code, [SQLITE_ERROR], following any
4256 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
4257 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
4258 ** specific [error codes] that better describes the error.
4259 ** We admit that this is a goofy design. The problem has been fixed
4260 ** with the "v2" interface. If you prepare all of your SQL statements
4261 ** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
4262 ** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
4263 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
4264 ** then the more specific [error codes] are returned directly
4265 ** by sqlite3_step(). The use of the "vX" interfaces is recommended.
4267 SQLITE_API int sqlite3_step(sqlite3_stmt*);
4270 ** CAPI3REF: Number of columns in a result set
4271 ** METHOD: sqlite3_stmt
4273 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
4274 ** current row of the result set of [prepared statement] P.
4275 ** ^If prepared statement P does not have results ready to return
4276 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
4277 ** interfaces) then sqlite3_data_count(P) returns 0.
4278 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
4279 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
4280 ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
4281 ** will return non-zero if previous call to [sqlite3_step](P) returned
4282 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
4283 ** where it always returns zero since each step of that multi-step
4284 ** pragma returns 0 columns of data.
4286 ** See also: [sqlite3_column_count()]
4288 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
4291 ** CAPI3REF: Fundamental Datatypes
4292 ** KEYWORDS: SQLITE_TEXT
4294 ** ^(Every value in SQLite has one of five fundamental datatypes:
4297 ** <li> 64-bit signed integer
4298 ** <li> 64-bit IEEE floating point number
4304 ** These constants are codes for each of those types.
4306 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
4307 ** for a completely different meaning. Software that links against both
4308 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
4311 #define SQLITE_INTEGER 1
4312 #define SQLITE_FLOAT 2
4313 #define SQLITE_BLOB 4
4314 #define SQLITE_NULL 5
4318 # define SQLITE_TEXT 3
4320 #define SQLITE3_TEXT 3
4323 ** CAPI3REF: Result Values From A Query
4324 ** KEYWORDS: {column access functions}
4325 ** METHOD: sqlite3_stmt
4328 ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
4329 ** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result
4330 ** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result
4331 ** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result
4332 ** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result
4333 ** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result
4334 ** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result
4335 ** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an
4336 ** [sqlite3_value|unprotected sqlite3_value] object.
4337 ** <tr><td> <td> <td>
4338 ** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB
4339 ** or a UTF-8 TEXT result in bytes
4340 ** <tr><td><b>sqlite3_column_bytes16 </b>
4341 ** <td>→ <td>Size of UTF-16
4343 ** <tr><td><b>sqlite3_column_type</b><td>→<td>Default
4344 ** datatype of the result
4345 ** </table></blockquote>
4349 ** ^These routines return information about a single column of the current
4350 ** result row of a query. ^In every case the first argument is a pointer
4351 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
4352 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
4353 ** and the second argument is the index of the column for which information
4354 ** should be returned. ^The leftmost column of the result set has the index 0.
4355 ** ^The number of columns in the result can be determined using
4356 ** [sqlite3_column_count()].
4358 ** If the SQL statement does not currently point to a valid row, or if the
4359 ** column index is out of range, the result is undefined.
4360 ** These routines may only be called when the most recent call to
4361 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
4362 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
4363 ** If any of these routines are called after [sqlite3_reset()] or
4364 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
4365 ** something other than [SQLITE_ROW], the results are undefined.
4366 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
4367 ** are called from a different thread while any of these routines
4368 ** are pending, then the results are undefined.
4370 ** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
4371 ** each return the value of a result column in a specific data format. If
4372 ** the result column is not initially in the requested format (for example,
4373 ** if the query returns an integer but the sqlite3_column_text() interface
4374 ** is used to extract the value) then an automatic type conversion is performed.
4376 ** ^The sqlite3_column_type() routine returns the
4377 ** [SQLITE_INTEGER | datatype code] for the initial data type
4378 ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
4379 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
4380 ** The return value of sqlite3_column_type() can be used to decide which
4381 ** of the first six interface should be used to extract the column value.
4382 ** The value returned by sqlite3_column_type() is only meaningful if no
4383 ** automatic type conversions have occurred for the value in question.
4384 ** After a type conversion, the result of calling sqlite3_column_type()
4385 ** is undefined, though harmless. Future
4386 ** versions of SQLite may change the behavior of sqlite3_column_type()
4387 ** following a type conversion.
4389 ** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
4390 ** or sqlite3_column_bytes16() interfaces can be used to determine the size
4391 ** of that BLOB or string.
4393 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
4394 ** routine returns the number of bytes in that BLOB or string.
4395 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
4396 ** the string to UTF-8 and then returns the number of bytes.
4397 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
4398 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
4399 ** the number of bytes in that string.
4400 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
4402 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
4403 ** routine returns the number of bytes in that BLOB or string.
4404 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
4405 ** the string to UTF-16 and then returns the number of bytes.
4406 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
4407 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
4408 ** the number of bytes in that string.
4409 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
4411 ** ^The values returned by [sqlite3_column_bytes()] and
4412 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
4413 ** of the string. ^For clarity: the values returned by
4414 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
4415 ** bytes in the string, not the number of characters.
4417 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
4418 ** even empty strings, are always zero-terminated. ^The return
4419 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
4421 ** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
4422 ** [unprotected sqlite3_value] object. In a multithreaded environment,
4423 ** an unprotected sqlite3_value object may only be used safely with
4424 ** [sqlite3_bind_value()] and [sqlite3_result_value()].
4425 ** If the [unprotected sqlite3_value] object returned by
4426 ** [sqlite3_column_value()] is used in any other way, including calls
4427 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
4428 ** or [sqlite3_value_bytes()], the behavior is not threadsafe.
4429 ** Hence, the sqlite3_column_value() interface
4430 ** is normally only useful within the implementation of
4431 ** [application-defined SQL functions] or [virtual tables], not within
4432 ** top-level application code.
4434 ** The these routines may attempt to convert the datatype of the result.
4435 ** ^For example, if the internal representation is FLOAT and a text result
4436 ** is requested, [sqlite3_snprintf()] is used internally to perform the
4437 ** conversion automatically. ^(The following table details the conversions
4438 ** that are applied:
4441 ** <table border="1">
4442 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
4444 ** <tr><td> NULL <td> INTEGER <td> Result is 0
4445 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
4446 ** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer
4447 ** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer
4448 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
4449 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
4450 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
4451 ** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER
4452 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
4453 ** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB
4454 ** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER
4455 ** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL
4456 ** <tr><td> TEXT <td> BLOB <td> No change
4457 ** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER
4458 ** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL
4459 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
4463 ** Note that when type conversions occur, pointers returned by prior
4464 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
4465 ** sqlite3_column_text16() may be invalidated.
4466 ** Type conversions and pointer invalidations might occur
4467 ** in the following cases:
4470 ** <li> The initial content is a BLOB and sqlite3_column_text() or
4471 ** sqlite3_column_text16() is called. A zero-terminator might
4472 ** need to be added to the string.</li>
4473 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
4474 ** sqlite3_column_text16() is called. The content must be converted
4476 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
4477 ** sqlite3_column_text() is called. The content must be converted
4481 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
4482 ** not invalidate a prior pointer, though of course the content of the buffer
4483 ** that the prior pointer references will have been modified. Other kinds
4484 ** of conversion are done in place when it is possible, but sometimes they
4485 ** are not possible and in those cases prior pointers are invalidated.
4487 ** The safest policy is to invoke these routines
4488 ** in one of the following ways:
4491 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
4492 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
4493 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
4496 ** In other words, you should call sqlite3_column_text(),
4497 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
4498 ** into the desired format, then invoke sqlite3_column_bytes() or
4499 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
4500 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
4501 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
4502 ** with calls to sqlite3_column_bytes().
4504 ** ^The pointers returned are valid until a type conversion occurs as
4505 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
4506 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
4507 ** and BLOBs is freed automatically. Do not pass the pointers returned
4508 ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
4509 ** [sqlite3_free()].
4511 ** ^(If a memory allocation error occurs during the evaluation of any
4512 ** of these routines, a default value is returned. The default value
4513 ** is either the integer 0, the floating point number 0.0, or a NULL
4514 ** pointer. Subsequent calls to [sqlite3_errcode()] will return
4515 ** [SQLITE_NOMEM].)^
4517 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
4518 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
4519 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
4520 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
4521 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
4522 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
4523 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
4524 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
4525 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
4526 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
4529 ** CAPI3REF: Destroy A Prepared Statement Object
4530 ** DESTRUCTOR: sqlite3_stmt
4532 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4533 ** ^If the most recent evaluation of the statement encountered no errors
4534 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
4535 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
4536 ** sqlite3_finalize(S) returns the appropriate [error code] or
4537 ** [extended error code].
4539 ** ^The sqlite3_finalize(S) routine can be called at any point during
4540 ** the life cycle of [prepared statement] S:
4541 ** before statement S is ever evaluated, after
4542 ** one or more calls to [sqlite3_reset()], or after any call
4543 ** to [sqlite3_step()] regardless of whether or not the statement has
4544 ** completed execution.
4546 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4548 ** The application must finalize every [prepared statement] in order to avoid
4549 ** resource leaks. It is a grievous error for the application to try to use
4550 ** a prepared statement after it has been finalized. Any use of a prepared
4551 ** statement after it has been finalized can result in undefined and
4552 ** undesirable behavior such as segfaults and heap corruption.
4554 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
4557 ** CAPI3REF: Reset A Prepared Statement Object
4558 ** METHOD: sqlite3_stmt
4560 ** The sqlite3_reset() function is called to reset a [prepared statement]
4561 ** object back to its initial state, ready to be re-executed.
4562 ** ^Any SQL statement variables that had values bound to them using
4563 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4564 ** Use [sqlite3_clear_bindings()] to reset the bindings.
4566 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4567 ** back to the beginning of its program.
4569 ** ^If the most recent call to [sqlite3_step(S)] for the
4570 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4571 ** or if [sqlite3_step(S)] has never before been called on S,
4572 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
4574 ** ^If the most recent call to [sqlite3_step(S)] for the
4575 ** [prepared statement] S indicated an error, then
4576 ** [sqlite3_reset(S)] returns an appropriate [error code].
4578 ** ^The [sqlite3_reset(S)] interface does not change the values
4579 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4581 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
4584 ** CAPI3REF: Create Or Redefine SQL Functions
4585 ** KEYWORDS: {function creation routines}
4586 ** KEYWORDS: {application-defined SQL function}
4587 ** KEYWORDS: {application-defined SQL functions}
4590 ** ^These functions (collectively known as "function creation routines")
4591 ** are used to add SQL functions or aggregates or to redefine the behavior
4592 ** of existing SQL functions or aggregates. The only differences between
4593 ** these routines are the text encoding expected for
4594 ** the second parameter (the name of the function being created)
4595 ** and the presence or absence of a destructor callback for
4596 ** the application data pointer.
4598 ** ^The first parameter is the [database connection] to which the SQL
4599 ** function is to be added. ^If an application uses more than one database
4600 ** connection then application-defined SQL functions must be added
4601 ** to each database connection separately.
4603 ** ^The second parameter is the name of the SQL function to be created or
4604 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
4605 ** representation, exclusive of the zero-terminator. ^Note that the name
4606 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4607 ** ^Any attempt to create a function with a longer name
4608 ** will result in [SQLITE_MISUSE] being returned.
4610 ** ^The third parameter (nArg)
4611 ** is the number of arguments that the SQL function or
4612 ** aggregate takes. ^If this parameter is -1, then the SQL function or
4613 ** aggregate may take any number of arguments between 0 and the limit
4614 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
4615 ** parameter is less than -1 or greater than 127 then the behavior is
4618 ** ^The fourth parameter, eTextRep, specifies what
4619 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4620 ** its parameters. The application should set this parameter to
4621 ** [SQLITE_UTF16LE] if the function implementation invokes
4622 ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4623 ** implementation invokes [sqlite3_value_text16be()] on an input, or
4624 ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4625 ** otherwise. ^The same SQL function may be registered multiple times using
4626 ** different preferred text encodings, with different implementations for
4628 ** ^When multiple implementations of the same function are available, SQLite
4629 ** will pick the one that involves the least amount of data conversion.
4631 ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4632 ** to signal that the function will always return the same result given
4633 ** the same inputs within a single SQL statement. Most SQL functions are
4634 ** deterministic. The built-in [random()] SQL function is an example of a
4635 ** function that is not deterministic. The SQLite query planner is able to
4636 ** perform additional optimizations on deterministic functions, so use
4637 ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4639 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
4640 ** function can gain access to this pointer using [sqlite3_user_data()].)^
4642 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
4643 ** pointers to C-language functions that implement the SQL function or
4644 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4645 ** callback only; NULL pointers must be passed as the xStep and xFinal
4646 ** parameters. ^An aggregate SQL function requires an implementation of xStep
4647 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4648 ** SQL function or aggregate, pass NULL pointers for all three function
4651 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
4652 ** then it is destructor for the application data pointer.
4653 ** The destructor is invoked when the function is deleted, either by being
4654 ** overloaded or when the database connection closes.)^
4655 ** ^The destructor is also invoked if the call to
4656 ** sqlite3_create_function_v2() fails.
4657 ** ^When the destructor callback of the tenth parameter is invoked, it
4658 ** is passed a single argument which is a copy of the application data
4659 ** pointer which was the fifth parameter to sqlite3_create_function_v2().
4661 ** ^It is permitted to register multiple implementations of the same
4662 ** functions with the same name but with either differing numbers of
4663 ** arguments or differing preferred text encodings. ^SQLite will use
4664 ** the implementation that most closely matches the way in which the
4665 ** SQL function is used. ^A function implementation with a non-negative
4666 ** nArg parameter is a better match than a function implementation with
4667 ** a negative nArg. ^A function where the preferred text encoding
4668 ** matches the database encoding is a better
4669 ** match than a function where the encoding is different.
4670 ** ^A function where the encoding difference is between UTF16le and UTF16be
4671 ** is a closer match than a function where the encoding difference is
4672 ** between UTF8 and UTF16.
4674 ** ^Built-in functions may be overloaded by new application-defined functions.
4676 ** ^An application-defined function is permitted to call other
4677 ** SQLite interfaces. However, such calls must not
4678 ** close the database connection nor finalize or reset the prepared
4679 ** statement in which the function is running.
4681 SQLITE_API int sqlite3_create_function(
4683 const char *zFunctionName,
4687 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4688 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4689 void (*xFinal)(sqlite3_context*)
4691 SQLITE_API int sqlite3_create_function16(
4693 const void *zFunctionName,
4697 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4698 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4699 void (*xFinal)(sqlite3_context*)
4701 SQLITE_API int sqlite3_create_function_v2(
4703 const char *zFunctionName,
4707 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4708 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4709 void (*xFinal)(sqlite3_context*),
4710 void(*xDestroy)(void*)
4714 ** CAPI3REF: Text Encodings
4716 ** These constant define integer codes that represent the various
4717 ** text encodings supported by SQLite.
4719 #define SQLITE_UTF8 1 /* IMP: R-37514-35566 */
4720 #define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */
4721 #define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */
4722 #define SQLITE_UTF16 4 /* Use native byte order */
4723 #define SQLITE_ANY 5 /* Deprecated */
4724 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
4727 ** CAPI3REF: Function Flags
4729 ** These constants may be ORed together with the
4730 ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4731 ** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4732 ** [sqlite3_create_function_v2()].
4734 #define SQLITE_DETERMINISTIC 0x800
4737 ** CAPI3REF: Deprecated Functions
4740 ** These functions are [deprecated]. In order to maintain
4741 ** backwards compatibility with older code, these functions continue
4742 ** to be supported. However, new applications should avoid
4743 ** the use of these functions. To encourage programmers to avoid
4744 ** these functions, we will not explain what they do.
4746 #ifndef SQLITE_OMIT_DEPRECATED
4747 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
4748 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
4749 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4750 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
4751 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
4752 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4753 void*,sqlite3_int64);
4757 ** CAPI3REF: Obtaining SQL Values
4758 ** METHOD: sqlite3_value
4761 ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
4762 ** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value
4763 ** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value
4764 ** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value
4765 ** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value
4766 ** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value
4767 ** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value
4768 ** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in
4769 ** the native byteorder
4770 ** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value
4771 ** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value
4772 ** <tr><td> <td> <td>
4773 ** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB
4774 ** or a UTF-8 TEXT in bytes
4775 ** <tr><td><b>sqlite3_value_bytes16 </b>
4776 ** <td>→ <td>Size of UTF-16
4778 ** <tr><td><b>sqlite3_value_type</b><td>→<td>Default
4779 ** datatype of the value
4780 ** <tr><td><b>sqlite3_value_numeric_type </b>
4781 ** <td>→ <td>Best numeric datatype of the value
4782 ** </table></blockquote>
4786 ** These routines extract type, size, and content information from
4787 ** [protected sqlite3_value] objects. Protected sqlite3_value objects
4788 ** are used to pass parameter information into implementation of
4789 ** [application-defined SQL functions] and [virtual tables].
4791 ** These routines work only with [protected sqlite3_value] objects.
4792 ** Any attempt to use these routines on an [unprotected sqlite3_value]
4793 ** is not threadsafe.
4795 ** ^These routines work just like the corresponding [column access functions]
4796 ** except that these routines take a single [protected sqlite3_value] object
4797 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4799 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4800 ** in the native byte-order of the host machine. ^The
4801 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4802 ** extract UTF-16 strings as big-endian and little-endian respectively.
4804 ** ^If [sqlite3_value] object V was initialized
4805 ** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
4806 ** and if X and Y are strings that compare equal according to strcmp(X,Y),
4807 ** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise,
4808 ** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
4809 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
4811 ** ^(The sqlite3_value_type(V) interface returns the
4812 ** [SQLITE_INTEGER | datatype code] for the initial datatype of the
4813 ** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
4814 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
4815 ** Other interfaces might change the datatype for an sqlite3_value object.
4816 ** For example, if the datatype is initially SQLITE_INTEGER and
4817 ** sqlite3_value_text(V) is called to extract a text value for that
4818 ** integer, then subsequent calls to sqlite3_value_type(V) might return
4819 ** SQLITE_TEXT. Whether or not a persistent internal datatype conversion
4820 ** occurs is undefined and may change from one release of SQLite to the next.
4822 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
4823 ** numeric affinity to the value. This means that an attempt is
4824 ** made to convert the value to an integer or floating point. If
4825 ** such a conversion is possible without loss of information (in other
4826 ** words, if the value is a string that looks like a number)
4827 ** then the conversion is performed. Otherwise no conversion occurs.
4828 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4830 ** Please pay particular attention to the fact that the pointer returned
4831 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4832 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4833 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4834 ** or [sqlite3_value_text16()].
4836 ** These routines must be called from the same thread as
4837 ** the SQL function that supplied the [sqlite3_value*] parameters.
4839 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
4840 SQLITE_API double sqlite3_value_double(sqlite3_value*);
4841 SQLITE_API int sqlite3_value_int(sqlite3_value*);
4842 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
4843 SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
4844 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
4845 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
4846 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
4847 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
4848 SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
4849 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
4850 SQLITE_API int sqlite3_value_type(sqlite3_value*);
4851 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
4854 ** CAPI3REF: Finding The Subtype Of SQL Values
4855 ** METHOD: sqlite3_value
4857 ** The sqlite3_value_subtype(V) function returns the subtype for
4858 ** an [application-defined SQL function] argument V. The subtype
4859 ** information can be used to pass a limited amount of context from
4860 ** one SQL function to another. Use the [sqlite3_result_subtype()]
4861 ** routine to set the subtype for the return value of an SQL function.
4863 SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
4866 ** CAPI3REF: Copy And Free SQL Values
4867 ** METHOD: sqlite3_value
4869 ** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
4870 ** object D and returns a pointer to that copy. ^The [sqlite3_value] returned
4871 ** is a [protected sqlite3_value] object even if the input is not.
4872 ** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
4873 ** memory allocation fails.
4875 ** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
4876 ** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer
4877 ** then sqlite3_value_free(V) is a harmless no-op.
4879 SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
4880 SQLITE_API void sqlite3_value_free(sqlite3_value*);
4883 ** CAPI3REF: Obtain Aggregate Function Context
4884 ** METHOD: sqlite3_context
4886 ** Implementations of aggregate SQL functions use this
4887 ** routine to allocate memory for storing their state.
4889 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4890 ** for a particular aggregate function, SQLite
4891 ** allocates N of memory, zeroes out that memory, and returns a pointer
4892 ** to the new memory. ^On second and subsequent calls to
4893 ** sqlite3_aggregate_context() for the same aggregate function instance,
4894 ** the same buffer is returned. Sqlite3_aggregate_context() is normally
4895 ** called once for each invocation of the xStep callback and then one
4896 ** last time when the xFinal callback is invoked. ^(When no rows match
4897 ** an aggregate query, the xStep() callback of the aggregate function
4898 ** implementation is never called and xFinal() is called exactly once.
4899 ** In those cases, sqlite3_aggregate_context() might be called for the
4900 ** first time from within xFinal().)^
4902 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
4903 ** when first called if N is less than or equal to zero or if a memory
4904 ** allocate error occurs.
4906 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4907 ** determined by the N parameter on first successful call. Changing the
4908 ** value of N in subsequent call to sqlite3_aggregate_context() within
4909 ** the same aggregate function instance will not resize the memory
4910 ** allocation.)^ Within the xFinal callback, it is customary to set
4911 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
4912 ** pointless memory allocations occur.
4914 ** ^SQLite automatically frees the memory allocated by
4915 ** sqlite3_aggregate_context() when the aggregate query concludes.
4917 ** The first parameter must be a copy of the
4918 ** [sqlite3_context | SQL function context] that is the first parameter
4919 ** to the xStep or xFinal callback routine that implements the aggregate
4922 ** This routine must be called from the same thread in which
4923 ** the aggregate SQL function is running.
4925 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4928 ** CAPI3REF: User Data For Functions
4929 ** METHOD: sqlite3_context
4931 ** ^The sqlite3_user_data() interface returns a copy of
4932 ** the pointer that was the pUserData parameter (the 5th parameter)
4933 ** of the [sqlite3_create_function()]
4934 ** and [sqlite3_create_function16()] routines that originally
4935 ** registered the application defined function.
4937 ** This routine must be called from the same thread in which
4938 ** the application-defined function is running.
4940 SQLITE_API void *sqlite3_user_data(sqlite3_context*);
4943 ** CAPI3REF: Database Connection For Functions
4944 ** METHOD: sqlite3_context
4946 ** ^The sqlite3_context_db_handle() interface returns a copy of
4947 ** the pointer to the [database connection] (the 1st parameter)
4948 ** of the [sqlite3_create_function()]
4949 ** and [sqlite3_create_function16()] routines that originally
4950 ** registered the application defined function.
4952 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
4955 ** CAPI3REF: Function Auxiliary Data
4956 ** METHOD: sqlite3_context
4958 ** These functions may be used by (non-aggregate) SQL functions to
4959 ** associate metadata with argument values. If the same value is passed to
4960 ** multiple invocations of the same SQL function during query execution, under
4961 ** some circumstances the associated metadata may be preserved. An example
4962 ** of where this might be useful is in a regular-expression matching
4963 ** function. The compiled version of the regular expression can be stored as
4964 ** metadata associated with the pattern string.
4965 ** Then as long as the pattern string remains the same,
4966 ** the compiled regular expression can be reused on multiple
4967 ** invocations of the same function.
4969 ** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata
4970 ** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
4971 ** value to the application-defined function. ^N is zero for the left-most
4972 ** function argument. ^If there is no metadata
4973 ** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
4974 ** returns a NULL pointer.
4976 ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
4977 ** argument of the application-defined function. ^Subsequent
4978 ** calls to sqlite3_get_auxdata(C,N) return P from the most recent
4979 ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
4980 ** NULL if the metadata has been discarded.
4981 ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
4982 ** SQLite will invoke the destructor function X with parameter P exactly
4983 ** once, when the metadata is discarded.
4984 ** SQLite is free to discard the metadata at any time, including: <ul>
4985 ** <li> ^(when the corresponding function parameter changes)^, or
4986 ** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
4987 ** SQL statement)^, or
4988 ** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
4990 ** <li> ^(during the original sqlite3_set_auxdata() call when a memory
4991 ** allocation error occurs.)^ </ul>
4993 ** Note the last bullet in particular. The destructor X in
4994 ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
4995 ** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
4996 ** should be called near the end of the function implementation and the
4997 ** function implementation should not make any use of P after
4998 ** sqlite3_set_auxdata() has been called.
5000 ** ^(In practice, metadata is preserved between function calls for
5001 ** function parameters that are compile-time constants, including literal
5002 ** values and [parameters] and expressions composed from the same.)^
5004 ** The value of the N parameter to these interfaces should be non-negative.
5005 ** Future enhancements may make use of negative N values to define new
5006 ** kinds of function caching behavior.
5008 ** These routines must be called from the same thread in which
5009 ** the SQL function is running.
5011 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
5012 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
5016 ** CAPI3REF: Constants Defining Special Destructor Behavior
5018 ** These are special values for the destructor that is passed in as the
5019 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
5020 ** argument is SQLITE_STATIC, it means that the content pointer is constant
5021 ** and will never change. It does not need to be destroyed. ^The
5022 ** SQLITE_TRANSIENT value means that the content will likely change in
5023 ** the near future and that SQLite should make its own private copy of
5024 ** the content before returning.
5026 ** The typedef is necessary to work around problems in certain
5029 typedef void (*sqlite3_destructor_type)(void*);
5030 #define SQLITE_STATIC ((sqlite3_destructor_type)0)
5031 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
5034 ** CAPI3REF: Setting The Result Of An SQL Function
5035 ** METHOD: sqlite3_context
5037 ** These routines are used by the xFunc or xFinal callbacks that
5038 ** implement SQL functions and aggregates. See
5039 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
5040 ** for additional information.
5042 ** These functions work very much like the [parameter binding] family of
5043 ** functions used to bind values to host parameters in prepared statements.
5044 ** Refer to the [SQL parameter] documentation for additional information.
5046 ** ^The sqlite3_result_blob() interface sets the result from
5047 ** an application-defined function to be the BLOB whose content is pointed
5048 ** to by the second parameter and which is N bytes long where N is the
5051 ** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
5052 ** interfaces set the result of the application-defined function to be
5053 ** a BLOB containing all zero bytes and N bytes in size.
5055 ** ^The sqlite3_result_double() interface sets the result from
5056 ** an application-defined function to be a floating point value specified
5057 ** by its 2nd argument.
5059 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
5060 ** cause the implemented SQL function to throw an exception.
5061 ** ^SQLite uses the string pointed to by the
5062 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
5063 ** as the text of an error message. ^SQLite interprets the error
5064 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
5065 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
5066 ** byte order. ^If the third parameter to sqlite3_result_error()
5067 ** or sqlite3_result_error16() is negative then SQLite takes as the error
5068 ** message all text up through the first zero character.
5069 ** ^If the third parameter to sqlite3_result_error() or
5070 ** sqlite3_result_error16() is non-negative then SQLite takes that many
5071 ** bytes (not characters) from the 2nd parameter as the error message.
5072 ** ^The sqlite3_result_error() and sqlite3_result_error16()
5073 ** routines make a private copy of the error message text before
5074 ** they return. Hence, the calling function can deallocate or
5075 ** modify the text after they return without harm.
5076 ** ^The sqlite3_result_error_code() function changes the error code
5077 ** returned by SQLite as a result of an error in a function. ^By default,
5078 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
5079 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
5081 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
5082 ** error indicating that a string or BLOB is too long to represent.
5084 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
5085 ** error indicating that a memory allocation failed.
5087 ** ^The sqlite3_result_int() interface sets the return value
5088 ** of the application-defined function to be the 32-bit signed integer
5089 ** value given in the 2nd argument.
5090 ** ^The sqlite3_result_int64() interface sets the return value
5091 ** of the application-defined function to be the 64-bit signed integer
5092 ** value given in the 2nd argument.
5094 ** ^The sqlite3_result_null() interface sets the return value
5095 ** of the application-defined function to be NULL.
5097 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
5098 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
5099 ** set the return value of the application-defined function to be
5100 ** a text string which is represented as UTF-8, UTF-16 native byte order,
5101 ** UTF-16 little endian, or UTF-16 big endian, respectively.
5102 ** ^The sqlite3_result_text64() interface sets the return value of an
5103 ** application-defined function to be a text string in an encoding
5104 ** specified by the fifth (and last) parameter, which must be one
5105 ** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
5106 ** ^SQLite takes the text result from the application from
5107 ** the 2nd parameter of the sqlite3_result_text* interfaces.
5108 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5109 ** is negative, then SQLite takes result text from the 2nd parameter
5110 ** through the first zero character.
5111 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5112 ** is non-negative, then as many bytes (not characters) of the text
5113 ** pointed to by the 2nd parameter are taken as the application-defined
5114 ** function result. If the 3rd parameter is non-negative, then it
5115 ** must be the byte offset into the string where the NUL terminator would
5116 ** appear if the string where NUL terminated. If any NUL characters occur
5117 ** in the string at a byte offset that is less than the value of the 3rd
5118 ** parameter, then the resulting string will contain embedded NULs and the
5119 ** result of expressions operating on strings with embedded NULs is undefined.
5120 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
5121 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
5122 ** function as the destructor on the text or BLOB result when it has
5123 ** finished using that result.
5124 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
5125 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
5126 ** assumes that the text or BLOB result is in constant space and does not
5127 ** copy the content of the parameter nor call a destructor on the content
5128 ** when it has finished using that result.
5129 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
5130 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
5131 ** then SQLite makes a copy of the result into space obtained
5132 ** from [sqlite3_malloc()] before it returns.
5134 ** ^The sqlite3_result_value() interface sets the result of
5135 ** the application-defined function to be a copy of the
5136 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
5137 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
5138 ** so that the [sqlite3_value] specified in the parameter may change or
5139 ** be deallocated after sqlite3_result_value() returns without harm.
5140 ** ^A [protected sqlite3_value] object may always be used where an
5141 ** [unprotected sqlite3_value] object is required, so either
5142 ** kind of [sqlite3_value] object can be used with this interface.
5144 ** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
5145 ** SQL NULL value, just like [sqlite3_result_null(C)], except that it
5146 ** also associates the host-language pointer P or type T with that
5147 ** NULL value such that the pointer can be retrieved within an
5148 ** [application-defined SQL function] using [sqlite3_value_pointer()].
5149 ** ^If the D parameter is not NULL, then it is a pointer to a destructor
5150 ** for the P parameter. ^SQLite invokes D with P as its only argument
5151 ** when SQLite is finished with P. The T parameter should be a static
5152 ** string and preferably a string literal. The sqlite3_result_pointer()
5153 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5155 ** If these routines are called from within the different thread
5156 ** than the one containing the application-defined function that received
5157 ** the [sqlite3_context] pointer, the results are undefined.
5159 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
5160 SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
5161 sqlite3_uint64,void(*)(void*));
5162 SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
5163 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
5164 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
5165 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
5166 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
5167 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
5168 SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
5169 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
5170 SQLITE_API void sqlite3_result_null(sqlite3_context*);
5171 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
5172 SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
5173 void(*)(void*), unsigned char encoding);
5174 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
5175 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
5176 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
5177 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
5178 SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
5179 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
5180 SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
5184 ** CAPI3REF: Setting The Subtype Of An SQL Function
5185 ** METHOD: sqlite3_context
5187 ** The sqlite3_result_subtype(C,T) function causes the subtype of
5188 ** the result from the [application-defined SQL function] with
5189 ** [sqlite3_context] C to be the value T. Only the lower 8 bits
5190 ** of the subtype T are preserved in current versions of SQLite;
5191 ** higher order bits are discarded.
5192 ** The number of subtype bytes preserved by SQLite might increase
5193 ** in future releases of SQLite.
5195 SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
5198 ** CAPI3REF: Define New Collating Sequences
5201 ** ^These functions add, remove, or modify a [collation] associated
5202 ** with the [database connection] specified as the first argument.
5204 ** ^The name of the collation is a UTF-8 string
5205 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
5206 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
5207 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
5208 ** considered to be the same name.
5210 ** ^(The third argument (eTextRep) must be one of the constants:
5212 ** <li> [SQLITE_UTF8],
5213 ** <li> [SQLITE_UTF16LE],
5214 ** <li> [SQLITE_UTF16BE],
5215 ** <li> [SQLITE_UTF16], or
5216 ** <li> [SQLITE_UTF16_ALIGNED].
5218 ** ^The eTextRep argument determines the encoding of strings passed
5219 ** to the collating function callback, xCallback.
5220 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
5221 ** force strings to be UTF16 with native byte order.
5222 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
5223 ** on an even byte address.
5225 ** ^The fourth argument, pArg, is an application data pointer that is passed
5226 ** through as the first argument to the collating function callback.
5228 ** ^The fifth argument, xCallback, is a pointer to the collating function.
5229 ** ^Multiple collating functions can be registered using the same name but
5230 ** with different eTextRep parameters and SQLite will use whichever
5231 ** function requires the least amount of data transformation.
5232 ** ^If the xCallback argument is NULL then the collating function is
5233 ** deleted. ^When all collating functions having the same name are deleted,
5234 ** that collation is no longer usable.
5236 ** ^The collating function callback is invoked with a copy of the pArg
5237 ** application data pointer and with two strings in the encoding specified
5238 ** by the eTextRep argument. The collating function must return an
5239 ** integer that is negative, zero, or positive
5240 ** if the first string is less than, equal to, or greater than the second,
5241 ** respectively. A collating function must always return the same answer
5242 ** given the same inputs. If two or more collating functions are registered
5243 ** to the same collation name (using different eTextRep values) then all
5244 ** must give an equivalent answer when invoked with equivalent strings.
5245 ** The collating function must obey the following properties for all
5246 ** strings A, B, and C:
5249 ** <li> If A==B then B==A.
5250 ** <li> If A==B and B==C then A==C.
5251 ** <li> If A<B THEN B>A.
5252 ** <li> If A<B and B<C then A<C.
5255 ** If a collating function fails any of the above constraints and that
5256 ** collating function is registered and used, then the behavior of SQLite
5259 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
5260 ** with the addition that the xDestroy callback is invoked on pArg when
5261 ** the collating function is deleted.
5262 ** ^Collating functions are deleted when they are overridden by later
5263 ** calls to the collation creation functions or when the
5264 ** [database connection] is closed using [sqlite3_close()].
5266 ** ^The xDestroy callback is <u>not</u> called if the
5267 ** sqlite3_create_collation_v2() function fails. Applications that invoke
5268 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
5269 ** check the return code and dispose of the application data pointer
5270 ** themselves rather than expecting SQLite to deal with it for them.
5271 ** This is different from every other SQLite interface. The inconsistency
5272 ** is unfortunate but cannot be changed without breaking backwards
5275 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
5277 SQLITE_API int sqlite3_create_collation(
5282 int(*xCompare)(void*,int,const void*,int,const void*)
5284 SQLITE_API int sqlite3_create_collation_v2(
5289 int(*xCompare)(void*,int,const void*,int,const void*),
5290 void(*xDestroy)(void*)
5292 SQLITE_API int sqlite3_create_collation16(
5297 int(*xCompare)(void*,int,const void*,int,const void*)
5301 ** CAPI3REF: Collation Needed Callbacks
5304 ** ^To avoid having to register all collation sequences before a database
5305 ** can be used, a single callback function may be registered with the
5306 ** [database connection] to be invoked whenever an undefined collation
5307 ** sequence is required.
5309 ** ^If the function is registered using the sqlite3_collation_needed() API,
5310 ** then it is passed the names of undefined collation sequences as strings
5311 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
5312 ** the names are passed as UTF-16 in machine native byte order.
5313 ** ^A call to either function replaces the existing collation-needed callback.
5315 ** ^(When the callback is invoked, the first argument passed is a copy
5316 ** of the second argument to sqlite3_collation_needed() or
5317 ** sqlite3_collation_needed16(). The second argument is the database
5318 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
5319 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
5320 ** sequence function required. The fourth parameter is the name of the
5321 ** required collation sequence.)^
5323 ** The callback function should register the desired collation using
5324 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
5325 ** [sqlite3_create_collation_v2()].
5327 SQLITE_API int sqlite3_collation_needed(
5330 void(*)(void*,sqlite3*,int eTextRep,const char*)
5332 SQLITE_API int sqlite3_collation_needed16(
5335 void(*)(void*,sqlite3*,int eTextRep,const void*)
5338 #ifdef SQLITE_HAS_CODEC
5340 ** Specify the key for an encrypted database. This routine should be
5341 ** called right after sqlite3_open().
5343 ** The code to implement this API is not available in the public release
5346 SQLITE_API int sqlite3_key(
5347 sqlite3 *db, /* Database to be rekeyed */
5348 const void *pKey, int nKey /* The key */
5350 SQLITE_API int sqlite3_key_v2(
5351 sqlite3 *db, /* Database to be rekeyed */
5352 const char *zDbName, /* Name of the database */
5353 const void *pKey, int nKey /* The key */
5357 ** Change the key on an open database. If the current database is not
5358 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
5359 ** database is decrypted.
5361 ** The code to implement this API is not available in the public release
5364 SQLITE_API int sqlite3_rekey(
5365 sqlite3 *db, /* Database to be rekeyed */
5366 const void *pKey, int nKey /* The new key */
5368 SQLITE_API int sqlite3_rekey_v2(
5369 sqlite3 *db, /* Database to be rekeyed */
5370 const char *zDbName, /* Name of the database */
5371 const void *pKey, int nKey /* The new key */
5375 ** Specify the activation key for a SEE database. Unless
5376 ** activated, none of the SEE routines will work.
5378 SQLITE_API void sqlite3_activate_see(
5379 const char *zPassPhrase /* Activation phrase */
5383 #ifdef SQLITE_ENABLE_CEROD
5385 ** Specify the activation key for a CEROD database. Unless
5386 ** activated, none of the CEROD routines will work.
5388 SQLITE_API void sqlite3_activate_cerod(
5389 const char *zPassPhrase /* Activation phrase */
5394 ** CAPI3REF: Suspend Execution For A Short Time
5396 ** The sqlite3_sleep() function causes the current thread to suspend execution
5397 ** for at least a number of milliseconds specified in its parameter.
5399 ** If the operating system does not support sleep requests with
5400 ** millisecond time resolution, then the time will be rounded up to
5401 ** the nearest second. The number of milliseconds of sleep actually
5402 ** requested from the operating system is returned.
5404 ** ^SQLite implements this interface by calling the xSleep()
5405 ** method of the default [sqlite3_vfs] object. If the xSleep() method
5406 ** of the default VFS is not implemented correctly, or not implemented at
5407 ** all, then the behavior of sqlite3_sleep() may deviate from the description
5408 ** in the previous paragraphs.
5410 SQLITE_API int sqlite3_sleep(int);
5413 ** CAPI3REF: Name Of The Folder Holding Temporary Files
5415 ** ^(If this global variable is made to point to a string which is
5416 ** the name of a folder (a.k.a. directory), then all temporary files
5417 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
5418 ** will be placed in that directory.)^ ^If this variable
5419 ** is a NULL pointer, then SQLite performs a search for an appropriate
5420 ** temporary file directory.
5422 ** Applications are strongly discouraged from using this global variable.
5423 ** It is required to set a temporary folder on Windows Runtime (WinRT).
5424 ** But for all other platforms, it is highly recommended that applications
5425 ** neither read nor write this variable. This global variable is a relic
5426 ** that exists for backwards compatibility of legacy applications and should
5427 ** be avoided in new projects.
5429 ** It is not safe to read or modify this variable in more than one
5430 ** thread at a time. It is not safe to read or modify this variable
5431 ** if a [database connection] is being used at the same time in a separate
5433 ** It is intended that this variable be set once
5434 ** as part of process initialization and before any SQLite interface
5435 ** routines have been called and that this variable remain unchanged
5438 ** ^The [temp_store_directory pragma] may modify this variable and cause
5439 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
5440 ** the [temp_store_directory pragma] always assumes that any string
5441 ** that this variable points to is held in memory obtained from
5442 ** [sqlite3_malloc] and the pragma may attempt to free that memory
5443 ** using [sqlite3_free].
5444 ** Hence, if this variable is modified directly, either it should be
5445 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
5446 ** or else the use of the [temp_store_directory pragma] should be avoided.
5447 ** Except when requested by the [temp_store_directory pragma], SQLite
5448 ** does not free the memory that sqlite3_temp_directory points to. If
5449 ** the application wants that memory to be freed, it must do
5450 ** so itself, taking care to only do so after all [database connection]
5451 ** objects have been destroyed.
5453 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
5454 ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
5455 ** features that require the use of temporary files may fail. Here is an
5456 ** example of how to do this using C++ with the Windows Runtime:
5458 ** <blockquote><pre>
5459 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
5460 ** TemporaryFolder->Path->Data();
5461 ** char zPathBuf[MAX_PATH + 1];
5462 ** memset(zPathBuf, 0, sizeof(zPathBuf));
5463 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
5464 ** NULL, NULL);
5465 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
5466 ** </pre></blockquote>
5468 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
5471 ** CAPI3REF: Name Of The Folder Holding Database Files
5473 ** ^(If this global variable is made to point to a string which is
5474 ** the name of a folder (a.k.a. directory), then all database files
5475 ** specified with a relative pathname and created or accessed by
5476 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
5477 ** to be relative to that directory.)^ ^If this variable is a NULL
5478 ** pointer, then SQLite assumes that all database files specified
5479 ** with a relative pathname are relative to the current directory
5480 ** for the process. Only the windows VFS makes use of this global
5481 ** variable; it is ignored by the unix VFS.
5483 ** Changing the value of this variable while a database connection is
5484 ** open can result in a corrupt database.
5486 ** It is not safe to read or modify this variable in more than one
5487 ** thread at a time. It is not safe to read or modify this variable
5488 ** if a [database connection] is being used at the same time in a separate
5490 ** It is intended that this variable be set once
5491 ** as part of process initialization and before any SQLite interface
5492 ** routines have been called and that this variable remain unchanged
5495 ** ^The [data_store_directory pragma] may modify this variable and cause
5496 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
5497 ** the [data_store_directory pragma] always assumes that any string
5498 ** that this variable points to is held in memory obtained from
5499 ** [sqlite3_malloc] and the pragma may attempt to free that memory
5500 ** using [sqlite3_free].
5501 ** Hence, if this variable is modified directly, either it should be
5502 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
5503 ** or else the use of the [data_store_directory pragma] should be avoided.
5505 SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
5508 ** CAPI3REF: Test For Auto-Commit Mode
5509 ** KEYWORDS: {autocommit mode}
5512 ** ^The sqlite3_get_autocommit() interface returns non-zero or
5513 ** zero if the given database connection is or is not in autocommit mode,
5514 ** respectively. ^Autocommit mode is on by default.
5515 ** ^Autocommit mode is disabled by a [BEGIN] statement.
5516 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
5518 ** If certain kinds of errors occur on a statement within a multi-statement
5519 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
5520 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
5521 ** transaction might be rolled back automatically. The only way to
5522 ** find out whether SQLite automatically rolled back the transaction after
5523 ** an error is to use this function.
5525 ** If another thread changes the autocommit status of the database
5526 ** connection while this routine is running, then the return value
5529 SQLITE_API int sqlite3_get_autocommit(sqlite3*);
5532 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
5533 ** METHOD: sqlite3_stmt
5535 ** ^The sqlite3_db_handle interface returns the [database connection] handle
5536 ** to which a [prepared statement] belongs. ^The [database connection]
5537 ** returned by sqlite3_db_handle is the same [database connection]
5538 ** that was the first argument
5539 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
5540 ** create the statement in the first place.
5542 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
5545 ** CAPI3REF: Return The Filename For A Database Connection
5548 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
5549 ** associated with database N of connection D. ^The main database file
5550 ** has the name "main". If there is no attached database N on the database
5551 ** connection D, or if database N is a temporary or in-memory database, then
5552 ** a NULL pointer is returned.
5554 ** ^The filename returned by this function is the output of the
5555 ** xFullPathname method of the [VFS]. ^In other words, the filename
5556 ** will be an absolute pathname, even if the filename used
5557 ** to open the database originally was a URI or relative pathname.
5559 SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
5562 ** CAPI3REF: Determine if a database is read-only
5565 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
5566 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
5567 ** the name of a database on connection D.
5569 SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
5572 ** CAPI3REF: Find the next prepared statement
5575 ** ^This interface returns a pointer to the next [prepared statement] after
5576 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
5577 ** then this interface returns a pointer to the first prepared statement
5578 ** associated with the database connection pDb. ^If no prepared statement
5579 ** satisfies the conditions of this routine, it returns NULL.
5581 ** The [database connection] pointer D in a call to
5582 ** [sqlite3_next_stmt(D,S)] must refer to an open database
5583 ** connection and in particular must not be a NULL pointer.
5585 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
5588 ** CAPI3REF: Commit And Rollback Notification Callbacks
5591 ** ^The sqlite3_commit_hook() interface registers a callback
5592 ** function to be invoked whenever a transaction is [COMMIT | committed].
5593 ** ^Any callback set by a previous call to sqlite3_commit_hook()
5594 ** for the same database connection is overridden.
5595 ** ^The sqlite3_rollback_hook() interface registers a callback
5596 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
5597 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
5598 ** for the same database connection is overridden.
5599 ** ^The pArg argument is passed through to the callback.
5600 ** ^If the callback on a commit hook function returns non-zero,
5601 ** then the commit is converted into a rollback.
5603 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
5604 ** return the P argument from the previous call of the same function
5605 ** on the same [database connection] D, or NULL for
5606 ** the first call for each function on D.
5608 ** The commit and rollback hook callbacks are not reentrant.
5609 ** The callback implementation must not do anything that will modify
5610 ** the database connection that invoked the callback. Any actions
5611 ** to modify the database connection must be deferred until after the
5612 ** completion of the [sqlite3_step()] call that triggered the commit
5613 ** or rollback hook in the first place.
5614 ** Note that running any other SQL statements, including SELECT statements,
5615 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
5616 ** the database connections for the meaning of "modify" in this paragraph.
5618 ** ^Registering a NULL function disables the callback.
5620 ** ^When the commit hook callback routine returns zero, the [COMMIT]
5621 ** operation is allowed to continue normally. ^If the commit hook
5622 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
5623 ** ^The rollback hook is invoked on a rollback that results from a commit
5624 ** hook returning non-zero, just as it would be with any other rollback.
5626 ** ^For the purposes of this API, a transaction is said to have been
5627 ** rolled back if an explicit "ROLLBACK" statement is executed, or
5628 ** an error or constraint causes an implicit rollback to occur.
5629 ** ^The rollback callback is not invoked if a transaction is
5630 ** automatically rolled back because the database connection is closed.
5632 ** See also the [sqlite3_update_hook()] interface.
5634 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
5635 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
5638 ** CAPI3REF: Data Change Notification Callbacks
5641 ** ^The sqlite3_update_hook() interface registers a callback function
5642 ** with the [database connection] identified by the first argument
5643 ** to be invoked whenever a row is updated, inserted or deleted in
5645 ** ^Any callback set by a previous call to this function
5646 ** for the same database connection is overridden.
5648 ** ^The second argument is a pointer to the function to invoke when a
5649 ** row is updated, inserted or deleted in a rowid table.
5650 ** ^The first argument to the callback is a copy of the third argument
5651 ** to sqlite3_update_hook().
5652 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
5653 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
5655 ** ^The third and fourth arguments to the callback contain pointers to the
5656 ** database and table name containing the affected row.
5657 ** ^The final callback parameter is the [rowid] of the row.
5658 ** ^In the case of an update, this is the [rowid] after the update takes place.
5660 ** ^(The update hook is not invoked when internal system tables are
5661 ** modified (i.e. sqlite_master and sqlite_sequence).)^
5662 ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
5664 ** ^In the current implementation, the update hook
5665 ** is not invoked when conflicting rows are deleted because of an
5666 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
5667 ** invoked when rows are deleted using the [truncate optimization].
5668 ** The exceptions defined in this paragraph might change in a future
5669 ** release of SQLite.
5671 ** The update hook implementation must not do anything that will modify
5672 ** the database connection that invoked the update hook. Any actions
5673 ** to modify the database connection must be deferred until after the
5674 ** completion of the [sqlite3_step()] call that triggered the update hook.
5675 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
5676 ** database connections for the meaning of "modify" in this paragraph.
5678 ** ^The sqlite3_update_hook(D,C,P) function
5679 ** returns the P argument from the previous call
5680 ** on the same [database connection] D, or NULL for
5681 ** the first call on D.
5683 ** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
5684 ** and [sqlite3_preupdate_hook()] interfaces.
5686 SQLITE_API void *sqlite3_update_hook(
5688 void(*)(void *,int ,char const *,char const *,sqlite3_int64),
5693 ** CAPI3REF: Enable Or Disable Shared Pager Cache
5695 ** ^(This routine enables or disables the sharing of the database cache
5696 ** and schema data structures between [database connection | connections]
5697 ** to the same database. Sharing is enabled if the argument is true
5698 ** and disabled if the argument is false.)^
5700 ** ^Cache sharing is enabled and disabled for an entire process.
5701 ** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
5702 ** In prior versions of SQLite,
5703 ** sharing was enabled or disabled for each thread separately.
5705 ** ^(The cache sharing mode set by this interface effects all subsequent
5706 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
5707 ** Existing database connections continue use the sharing mode
5708 ** that was in effect at the time they were opened.)^
5710 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
5711 ** successfully. An [error code] is returned otherwise.)^
5713 ** ^Shared cache is disabled by default. But this might change in
5714 ** future releases of SQLite. Applications that care about shared
5715 ** cache setting should set it explicitly.
5717 ** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
5718 ** and will always return SQLITE_MISUSE. On those systems,
5719 ** shared cache mode should be enabled per-database connection via
5720 ** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
5722 ** This interface is threadsafe on processors where writing a
5723 ** 32-bit integer is atomic.
5725 ** See Also: [SQLite Shared-Cache Mode]
5727 SQLITE_API int sqlite3_enable_shared_cache(int);
5730 ** CAPI3REF: Attempt To Free Heap Memory
5732 ** ^The sqlite3_release_memory() interface attempts to free N bytes
5733 ** of heap memory by deallocating non-essential memory allocations
5734 ** held by the database library. Memory used to cache database
5735 ** pages to improve performance is an example of non-essential memory.
5736 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
5737 ** which might be more or less than the amount requested.
5738 ** ^The sqlite3_release_memory() routine is a no-op returning zero
5739 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5741 ** See also: [sqlite3_db_release_memory()]
5743 SQLITE_API int sqlite3_release_memory(int);
5746 ** CAPI3REF: Free Memory Used By A Database Connection
5749 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
5750 ** memory as possible from database connection D. Unlike the
5751 ** [sqlite3_release_memory()] interface, this interface is in effect even
5752 ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
5755 ** See also: [sqlite3_release_memory()]
5757 SQLITE_API int sqlite3_db_release_memory(sqlite3*);
5760 ** CAPI3REF: Impose A Limit On Heap Size
5762 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
5763 ** soft limit on the amount of heap memory that may be allocated by SQLite.
5764 ** ^SQLite strives to keep heap memory utilization below the soft heap
5765 ** limit by reducing the number of pages held in the page cache
5766 ** as heap memory usages approaches the limit.
5767 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
5768 ** below the limit, it will exceed the limit rather than generate
5769 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
5770 ** is advisory only.
5772 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
5773 ** the soft heap limit prior to the call, or negative in the case of an
5774 ** error. ^If the argument N is negative
5775 ** then no change is made to the soft heap limit. Hence, the current
5776 ** size of the soft heap limit can be determined by invoking
5777 ** sqlite3_soft_heap_limit64() with a negative argument.
5779 ** ^If the argument N is zero then the soft heap limit is disabled.
5781 ** ^(The soft heap limit is not enforced in the current implementation
5782 ** if one or more of following conditions are true:
5785 ** <li> The soft heap limit is set to zero.
5786 ** <li> Memory accounting is disabled using a combination of the
5787 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
5788 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
5789 ** <li> An alternative page cache implementation is specified using
5790 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
5791 ** <li> The page cache allocates from its own memory pool supplied
5792 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
5796 ** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]),
5797 ** the soft heap limit is enforced
5798 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
5799 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
5800 ** the soft heap limit is enforced on every memory allocation. Without
5801 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
5802 ** when memory is allocated by the page cache. Testing suggests that because
5803 ** the page cache is the predominate memory user in SQLite, most
5804 ** applications will achieve adequate soft heap limit enforcement without
5805 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5807 ** The circumstances under which SQLite will enforce the soft heap limit may
5808 ** changes in future releases of SQLite.
5810 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
5813 ** CAPI3REF: Deprecated Soft Heap Limit Interface
5816 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
5817 ** interface. This routine is provided for historical compatibility
5818 ** only. All new applications should use the
5819 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
5821 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
5825 ** CAPI3REF: Extract Metadata About A Column Of A Table
5828 ** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
5829 ** information about column C of table T in database D
5830 ** on [database connection] X.)^ ^The sqlite3_table_column_metadata()
5831 ** interface returns SQLITE_OK and fills in the non-NULL pointers in
5832 ** the final five arguments with appropriate values if the specified
5833 ** column exists. ^The sqlite3_table_column_metadata() interface returns
5834 ** SQLITE_ERROR and if the specified column does not exist.
5835 ** ^If the column-name parameter to sqlite3_table_column_metadata() is a
5836 ** NULL pointer, then this routine simply checks for the existence of the
5837 ** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
5838 ** does not. If the table name parameter T in a call to
5839 ** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
5840 ** undefined behavior.
5842 ** ^The column is identified by the second, third and fourth parameters to
5843 ** this function. ^(The second parameter is either the name of the database
5844 ** (i.e. "main", "temp", or an attached database) containing the specified
5845 ** table or NULL.)^ ^If it is NULL, then all attached databases are searched
5846 ** for the table using the same algorithm used by the database engine to
5847 ** resolve unqualified table references.
5849 ** ^The third and fourth parameters to this function are the table and column
5850 ** name of the desired column, respectively.
5852 ** ^Metadata is returned by writing to the memory locations passed as the 5th
5853 ** and subsequent parameters to this function. ^Any of these arguments may be
5854 ** NULL, in which case the corresponding element of metadata is omitted.
5857 ** <table border="1">
5858 ** <tr><th> Parameter <th> Output<br>Type <th> Description
5860 ** <tr><td> 5th <td> const char* <td> Data type
5861 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
5862 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
5863 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
5864 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
5868 ** ^The memory pointed to by the character pointers returned for the
5869 ** declaration type and collation sequence is valid until the next
5870 ** call to any SQLite API function.
5872 ** ^If the specified table is actually a view, an [error code] is returned.
5874 ** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
5875 ** is not a [WITHOUT ROWID] table and an
5876 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
5877 ** parameters are set for the explicitly declared column. ^(If there is no
5878 ** [INTEGER PRIMARY KEY] column, then the outputs
5879 ** for the [rowid] are set as follows:
5882 ** data type: "INTEGER"
5883 ** collation sequence: "BINARY"
5886 ** auto increment: 0
5889 ** ^This function causes all database schemas to be read from disk and
5890 ** parsed, if that has not already been done, and returns an error if
5891 ** any errors are encountered while loading the schema.
5893 SQLITE_API int sqlite3_table_column_metadata(
5894 sqlite3 *db, /* Connection handle */
5895 const char *zDbName, /* Database name or NULL */
5896 const char *zTableName, /* Table name */
5897 const char *zColumnName, /* Column name */
5898 char const **pzDataType, /* OUTPUT: Declared data type */
5899 char const **pzCollSeq, /* OUTPUT: Collation sequence name */
5900 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
5901 int *pPrimaryKey, /* OUTPUT: True if column part of PK */
5902 int *pAutoinc /* OUTPUT: True if column is auto-increment */
5906 ** CAPI3REF: Load An Extension
5909 ** ^This interface loads an SQLite extension library from the named file.
5911 ** ^The sqlite3_load_extension() interface attempts to load an
5912 ** [SQLite extension] library contained in the file zFile. If
5913 ** the file cannot be loaded directly, attempts are made to load
5914 ** with various operating-system specific extensions added.
5915 ** So for example, if "samplelib" cannot be loaded, then names like
5916 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
5919 ** ^The entry point is zProc.
5920 ** ^(zProc may be 0, in which case SQLite will try to come up with an
5921 ** entry point name on its own. It first tries "sqlite3_extension_init".
5922 ** If that does not work, it constructs a name "sqlite3_X_init" where the
5923 ** X is consists of the lower-case equivalent of all ASCII alphabetic
5924 ** characters in the filename from the last "/" to the first following
5925 ** "." and omitting any initial "lib".)^
5926 ** ^The sqlite3_load_extension() interface returns
5927 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
5928 ** ^If an error occurs and pzErrMsg is not 0, then the
5929 ** [sqlite3_load_extension()] interface shall attempt to
5930 ** fill *pzErrMsg with error message text stored in memory
5931 ** obtained from [sqlite3_malloc()]. The calling function
5932 ** should free this memory by calling [sqlite3_free()].
5934 ** ^Extension loading must be enabled using
5935 ** [sqlite3_enable_load_extension()] or
5936 ** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
5937 ** prior to calling this API,
5938 ** otherwise an error will be returned.
5940 ** <b>Security warning:</b> It is recommended that the
5941 ** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
5942 ** interface. The use of the [sqlite3_enable_load_extension()] interface
5943 ** should be avoided. This will keep the SQL function [load_extension()]
5944 ** disabled and prevent SQL injections from giving attackers
5945 ** access to extension loading capabilities.
5947 ** See also the [load_extension() SQL function].
5949 SQLITE_API int sqlite3_load_extension(
5950 sqlite3 *db, /* Load the extension into this database connection */
5951 const char *zFile, /* Name of the shared library containing extension */
5952 const char *zProc, /* Entry point. Derived from zFile if 0 */
5953 char **pzErrMsg /* Put error message here if not 0 */
5957 ** CAPI3REF: Enable Or Disable Extension Loading
5960 ** ^So as not to open security holes in older applications that are
5961 ** unprepared to deal with [extension loading], and as a means of disabling
5962 ** [extension loading] while evaluating user-entered SQL, the following API
5963 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5965 ** ^Extension loading is off by default.
5966 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5967 ** to turn extension loading on and call it with onoff==0 to turn
5968 ** it back off again.
5970 ** ^This interface enables or disables both the C-API
5971 ** [sqlite3_load_extension()] and the SQL function [load_extension()].
5972 ** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
5973 ** to enable or disable only the C-API.)^
5975 ** <b>Security warning:</b> It is recommended that extension loading
5976 ** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
5977 ** rather than this interface, so the [load_extension()] SQL function
5978 ** remains disabled. This will prevent SQL injections from giving attackers
5979 ** access to extension loading capabilities.
5981 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
5984 ** CAPI3REF: Automatically Load Statically Linked Extensions
5986 ** ^This interface causes the xEntryPoint() function to be invoked for
5987 ** each new [database connection] that is created. The idea here is that
5988 ** xEntryPoint() is the entry point for a statically linked [SQLite extension]
5989 ** that is to be automatically loaded into all new database connections.
5991 ** ^(Even though the function prototype shows that xEntryPoint() takes
5992 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
5993 ** arguments and expects an integer result as if the signature of the
5994 ** entry point where as follows:
5996 ** <blockquote><pre>
5997 ** int xEntryPoint(
5998 ** sqlite3 *db,
5999 ** const char **pzErrMsg,
6000 ** const struct sqlite3_api_routines *pThunk
6002 ** </pre></blockquote>)^
6004 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
6005 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
6006 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
6007 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
6008 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
6009 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
6010 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
6012 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
6013 ** on the list of automatic extensions is a harmless no-op. ^No entry point
6014 ** will be called more than once for each database connection that is opened.
6016 ** See also: [sqlite3_reset_auto_extension()]
6017 ** and [sqlite3_cancel_auto_extension()]
6019 SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
6022 ** CAPI3REF: Cancel Automatic Extension Loading
6024 ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
6025 ** initialization routine X that was registered using a prior call to
6026 ** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)]
6027 ** routine returns 1 if initialization routine X was successfully
6028 ** unregistered and it returns 0 if X was not on the list of initialization
6031 SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
6034 ** CAPI3REF: Reset Automatic Extension Loading
6036 ** ^This interface disables all automatic extensions previously
6037 ** registered using [sqlite3_auto_extension()].
6039 SQLITE_API void sqlite3_reset_auto_extension(void);
6042 ** The interface to the virtual-table mechanism is currently considered
6043 ** to be experimental. The interface might change in incompatible ways.
6044 ** If this is a problem for you, do not use the interface at this time.
6046 ** When the virtual-table mechanism stabilizes, we will declare the
6047 ** interface fixed, support it indefinitely, and remove this comment.
6051 ** Structures used by the virtual table interface
6053 typedef struct sqlite3_vtab sqlite3_vtab;
6054 typedef struct sqlite3_index_info sqlite3_index_info;
6055 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
6056 typedef struct sqlite3_module sqlite3_module;
6059 ** CAPI3REF: Virtual Table Object
6060 ** KEYWORDS: sqlite3_module {virtual table module}
6062 ** This structure, sometimes called a "virtual table module",
6063 ** defines the implementation of a [virtual tables].
6064 ** This structure consists mostly of methods for the module.
6066 ** ^A virtual table module is created by filling in a persistent
6067 ** instance of this structure and passing a pointer to that instance
6068 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
6069 ** ^The registration remains valid until it is replaced by a different
6070 ** module or until the [database connection] closes. The content
6071 ** of this structure must not change while it is registered with
6072 ** any database connection.
6074 struct sqlite3_module {
6076 int (*xCreate)(sqlite3*, void *pAux,
6077 int argc, const char *const*argv,
6078 sqlite3_vtab **ppVTab, char**);
6079 int (*xConnect)(sqlite3*, void *pAux,
6080 int argc, const char *const*argv,
6081 sqlite3_vtab **ppVTab, char**);
6082 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
6083 int (*xDisconnect)(sqlite3_vtab *pVTab);
6084 int (*xDestroy)(sqlite3_vtab *pVTab);
6085 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
6086 int (*xClose)(sqlite3_vtab_cursor*);
6087 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
6088 int argc, sqlite3_value **argv);
6089 int (*xNext)(sqlite3_vtab_cursor*);
6090 int (*xEof)(sqlite3_vtab_cursor*);
6091 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
6092 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
6093 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
6094 int (*xBegin)(sqlite3_vtab *pVTab);
6095 int (*xSync)(sqlite3_vtab *pVTab);
6096 int (*xCommit)(sqlite3_vtab *pVTab);
6097 int (*xRollback)(sqlite3_vtab *pVTab);
6098 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
6099 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
6101 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
6102 /* The methods above are in version 1 of the sqlite_module object. Those
6103 ** below are for version 2 and greater. */
6104 int (*xSavepoint)(sqlite3_vtab *pVTab, int);
6105 int (*xRelease)(sqlite3_vtab *pVTab, int);
6106 int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
6110 ** CAPI3REF: Virtual Table Indexing Information
6111 ** KEYWORDS: sqlite3_index_info
6113 ** The sqlite3_index_info structure and its substructures is used as part
6114 ** of the [virtual table] interface to
6115 ** pass information into and receive the reply from the [xBestIndex]
6116 ** method of a [virtual table module]. The fields under **Inputs** are the
6117 ** inputs to xBestIndex and are read-only. xBestIndex inserts its
6118 ** results into the **Outputs** fields.
6120 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
6122 ** <blockquote>column OP expr</blockquote>
6124 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is
6125 ** stored in aConstraint[].op using one of the
6126 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
6127 ** ^(The index of the column is stored in
6128 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
6129 ** expr on the right-hand side can be evaluated (and thus the constraint
6130 ** is usable) and false if it cannot.)^
6132 ** ^The optimizer automatically inverts terms of the form "expr OP column"
6133 ** and makes other simplifications to the WHERE clause in an attempt to
6134 ** get as many WHERE clause terms into the form shown above as possible.
6135 ** ^The aConstraint[] array only reports WHERE clause terms that are
6136 ** relevant to the particular virtual table being queried.
6138 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
6139 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
6141 ** The colUsed field indicates which columns of the virtual table may be
6142 ** required by the current scan. Virtual table columns are numbered from
6143 ** zero in the order in which they appear within the CREATE TABLE statement
6144 ** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
6145 ** the corresponding bit is set within the colUsed mask if the column may be
6146 ** required by SQLite. If the table has at least 64 columns and any column
6147 ** to the right of the first 63 is required, then bit 63 of colUsed is also
6148 ** set. In other words, column iCol may be required if the expression
6149 ** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
6152 ** The [xBestIndex] method must fill aConstraintUsage[] with information
6153 ** about what parameters to pass to xFilter. ^If argvIndex>0 then
6154 ** the right-hand side of the corresponding aConstraint[] is evaluated
6155 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
6156 ** is true, then the constraint is assumed to be fully handled by the
6157 ** virtual table and is not checked again by SQLite.)^
6159 ** ^The idxNum and idxPtr values are recorded and passed into the
6160 ** [xFilter] method.
6161 ** ^[sqlite3_free()] is used to free idxPtr if and only if
6162 ** needToFreeIdxPtr is true.
6164 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
6165 ** the correct order to satisfy the ORDER BY clause so that no separate
6166 ** sorting step is required.
6168 ** ^The estimatedCost value is an estimate of the cost of a particular
6169 ** strategy. A cost of N indicates that the cost of the strategy is similar
6170 ** to a linear scan of an SQLite table with N rows. A cost of log(N)
6171 ** indicates that the expense of the operation is similar to that of a
6172 ** binary search on a unique indexed field of an SQLite table with N rows.
6174 ** ^The estimatedRows value is an estimate of the number of rows that
6175 ** will be returned by the strategy.
6177 ** The xBestIndex method may optionally populate the idxFlags field with a
6178 ** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
6179 ** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
6180 ** assumes that the strategy may visit at most one row.
6182 ** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
6183 ** SQLite also assumes that if a call to the xUpdate() method is made as
6184 ** part of the same statement to delete or update a virtual table row and the
6185 ** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
6186 ** any database changes. In other words, if the xUpdate() returns
6187 ** SQLITE_CONSTRAINT, the database contents must be exactly as they were
6188 ** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
6189 ** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
6190 ** the xUpdate method are automatically rolled back by SQLite.
6192 ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
6193 ** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
6194 ** If a virtual table extension is
6195 ** used with an SQLite version earlier than 3.8.2, the results of attempting
6196 ** to read or write the estimatedRows field are undefined (but are likely
6197 ** to included crashing the application). The estimatedRows field should
6198 ** therefore only be used if [sqlite3_libversion_number()] returns a
6199 ** value greater than or equal to 3008002. Similarly, the idxFlags field
6200 ** was added for [version 3.9.0] ([dateof:3.9.0]).
6201 ** It may therefore only be used if
6202 ** sqlite3_libversion_number() returns a value greater than or equal to
6205 struct sqlite3_index_info {
6207 int nConstraint; /* Number of entries in aConstraint */
6208 struct sqlite3_index_constraint {
6209 int iColumn; /* Column constrained. -1 for ROWID */
6210 unsigned char op; /* Constraint operator */
6211 unsigned char usable; /* True if this constraint is usable */
6212 int iTermOffset; /* Used internally - xBestIndex should ignore */
6213 } *aConstraint; /* Table of WHERE clause constraints */
6214 int nOrderBy; /* Number of terms in the ORDER BY clause */
6215 struct sqlite3_index_orderby {
6216 int iColumn; /* Column number */
6217 unsigned char desc; /* True for DESC. False for ASC. */
6218 } *aOrderBy; /* The ORDER BY clause */
6220 struct sqlite3_index_constraint_usage {
6221 int argvIndex; /* if >0, constraint is part of argv to xFilter */
6222 unsigned char omit; /* Do not code a test for this constraint */
6223 } *aConstraintUsage;
6224 int idxNum; /* Number used to identify the index */
6225 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
6226 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
6227 int orderByConsumed; /* True if output is already ordered */
6228 double estimatedCost; /* Estimated cost of using this index */
6229 /* Fields below are only available in SQLite 3.8.2 and later */
6230 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */
6231 /* Fields below are only available in SQLite 3.9.0 and later */
6232 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */
6233 /* Fields below are only available in SQLite 3.10.0 and later */
6234 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */
6238 ** CAPI3REF: Virtual Table Scan Flags
6240 #define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */
6243 ** CAPI3REF: Virtual Table Constraint Operator Codes
6245 ** These macros defined the allowed values for the
6246 ** [sqlite3_index_info].aConstraint[].op field. Each value represents
6247 ** an operator that is part of a constraint term in the wHERE clause of
6248 ** a query that uses a [virtual table].
6250 #define SQLITE_INDEX_CONSTRAINT_EQ 2
6251 #define SQLITE_INDEX_CONSTRAINT_GT 4
6252 #define SQLITE_INDEX_CONSTRAINT_LE 8
6253 #define SQLITE_INDEX_CONSTRAINT_LT 16
6254 #define SQLITE_INDEX_CONSTRAINT_GE 32
6255 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
6256 #define SQLITE_INDEX_CONSTRAINT_LIKE 65
6257 #define SQLITE_INDEX_CONSTRAINT_GLOB 66
6258 #define SQLITE_INDEX_CONSTRAINT_REGEXP 67
6259 #define SQLITE_INDEX_CONSTRAINT_NE 68
6260 #define SQLITE_INDEX_CONSTRAINT_ISNOT 69
6261 #define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70
6262 #define SQLITE_INDEX_CONSTRAINT_ISNULL 71
6263 #define SQLITE_INDEX_CONSTRAINT_IS 72
6266 ** CAPI3REF: Register A Virtual Table Implementation
6269 ** ^These routines are used to register a new [virtual table module] name.
6270 ** ^Module names must be registered before
6271 ** creating a new [virtual table] using the module and before using a
6272 ** preexisting [virtual table] for the module.
6274 ** ^The module name is registered on the [database connection] specified
6275 ** by the first parameter. ^The name of the module is given by the
6276 ** second parameter. ^The third parameter is a pointer to
6277 ** the implementation of the [virtual table module]. ^The fourth
6278 ** parameter is an arbitrary client data pointer that is passed through
6279 ** into the [xCreate] and [xConnect] methods of the virtual table module
6280 ** when a new virtual table is be being created or reinitialized.
6282 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
6283 ** is a pointer to a destructor for the pClientData. ^SQLite will
6284 ** invoke the destructor function (if it is not NULL) when SQLite
6285 ** no longer needs the pClientData pointer. ^The destructor will also
6286 ** be invoked if the call to sqlite3_create_module_v2() fails.
6287 ** ^The sqlite3_create_module()
6288 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
6291 SQLITE_API int sqlite3_create_module(
6292 sqlite3 *db, /* SQLite connection to register module with */
6293 const char *zName, /* Name of the module */
6294 const sqlite3_module *p, /* Methods for the module */
6295 void *pClientData /* Client data for xCreate/xConnect */
6297 SQLITE_API int sqlite3_create_module_v2(
6298 sqlite3 *db, /* SQLite connection to register module with */
6299 const char *zName, /* Name of the module */
6300 const sqlite3_module *p, /* Methods for the module */
6301 void *pClientData, /* Client data for xCreate/xConnect */
6302 void(*xDestroy)(void*) /* Module destructor function */
6306 ** CAPI3REF: Virtual Table Instance Object
6307 ** KEYWORDS: sqlite3_vtab
6309 ** Every [virtual table module] implementation uses a subclass
6310 ** of this object to describe a particular instance
6311 ** of the [virtual table]. Each subclass will
6312 ** be tailored to the specific needs of the module implementation.
6313 ** The purpose of this superclass is to define certain fields that are
6314 ** common to all module implementations.
6316 ** ^Virtual tables methods can set an error message by assigning a
6317 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
6318 ** take care that any prior string is freed by a call to [sqlite3_free()]
6319 ** prior to assigning a new string to zErrMsg. ^After the error message
6320 ** is delivered up to the client application, the string will be automatically
6321 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
6323 struct sqlite3_vtab {
6324 const sqlite3_module *pModule; /* The module for this virtual table */
6325 int nRef; /* Number of open cursors */
6326 char *zErrMsg; /* Error message from sqlite3_mprintf() */
6327 /* Virtual table implementations will typically add additional fields */
6331 ** CAPI3REF: Virtual Table Cursor Object
6332 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
6334 ** Every [virtual table module] implementation uses a subclass of the
6335 ** following structure to describe cursors that point into the
6336 ** [virtual table] and are used
6337 ** to loop through the virtual table. Cursors are created using the
6338 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
6339 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
6340 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
6341 ** of the module. Each module implementation will define
6342 ** the content of a cursor structure to suit its own needs.
6344 ** This superclass exists in order to define fields of the cursor that
6345 ** are common to all implementations.
6347 struct sqlite3_vtab_cursor {
6348 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
6349 /* Virtual table implementations will typically add additional fields */
6353 ** CAPI3REF: Declare The Schema Of A Virtual Table
6355 ** ^The [xCreate] and [xConnect] methods of a
6356 ** [virtual table module] call this interface
6357 ** to declare the format (the names and datatypes of the columns) of
6358 ** the virtual tables they implement.
6360 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
6363 ** CAPI3REF: Overload A Function For A Virtual Table
6366 ** ^(Virtual tables can provide alternative implementations of functions
6367 ** using the [xFindFunction] method of the [virtual table module].
6368 ** But global versions of those functions
6369 ** must exist in order to be overloaded.)^
6371 ** ^(This API makes sure a global version of a function with a particular
6372 ** name and number of parameters exists. If no such function exists
6373 ** before this API is called, a new function is created.)^ ^The implementation
6374 ** of the new function always causes an exception to be thrown. So
6375 ** the new function is not good for anything by itself. Its only
6376 ** purpose is to be a placeholder function that can be overloaded
6377 ** by a [virtual table].
6379 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
6382 ** The interface to the virtual-table mechanism defined above (back up
6383 ** to a comment remarkably similar to this one) is currently considered
6384 ** to be experimental. The interface might change in incompatible ways.
6385 ** If this is a problem for you, do not use the interface at this time.
6387 ** When the virtual-table mechanism stabilizes, we will declare the
6388 ** interface fixed, support it indefinitely, and remove this comment.
6392 ** CAPI3REF: A Handle To An Open BLOB
6393 ** KEYWORDS: {BLOB handle} {BLOB handles}
6395 ** An instance of this object represents an open BLOB on which
6396 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
6397 ** ^Objects of this type are created by [sqlite3_blob_open()]
6398 ** and destroyed by [sqlite3_blob_close()].
6399 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
6400 ** can be used to read or write small subsections of the BLOB.
6401 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
6403 typedef struct sqlite3_blob sqlite3_blob;
6406 ** CAPI3REF: Open A BLOB For Incremental I/O
6408 ** CONSTRUCTOR: sqlite3_blob
6410 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
6411 ** in row iRow, column zColumn, table zTable in database zDb;
6412 ** in other words, the same BLOB that would be selected by:
6415 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
6418 ** ^(Parameter zDb is not the filename that contains the database, but
6419 ** rather the symbolic name of the database. For attached databases, this is
6420 ** the name that appears after the AS keyword in the [ATTACH] statement.
6421 ** For the main database file, the database name is "main". For TEMP
6422 ** tables, the database name is "temp".)^
6424 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
6425 ** and write access. ^If the flags parameter is zero, the BLOB is opened for
6426 ** read-only access.
6428 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
6429 ** in *ppBlob. Otherwise an [error code] is returned and, unless the error
6430 ** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
6431 ** the API is not misused, it is always safe to call [sqlite3_blob_close()]
6432 ** on *ppBlob after this function it returns.
6434 ** This function fails with SQLITE_ERROR if any of the following are true:
6436 ** <li> ^(Database zDb does not exist)^,
6437 ** <li> ^(Table zTable does not exist within database zDb)^,
6438 ** <li> ^(Table zTable is a WITHOUT ROWID table)^,
6439 ** <li> ^(Column zColumn does not exist)^,
6440 ** <li> ^(Row iRow is not present in the table)^,
6441 ** <li> ^(The specified column of row iRow contains a value that is not
6442 ** a TEXT or BLOB value)^,
6443 ** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
6444 ** constraint and the blob is being opened for read/write access)^,
6445 ** <li> ^([foreign key constraints | Foreign key constraints] are enabled,
6446 ** column zColumn is part of a [child key] definition and the blob is
6447 ** being opened for read/write access)^.
6450 ** ^Unless it returns SQLITE_MISUSE, this function sets the
6451 ** [database connection] error code and message accessible via
6452 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6454 ** A BLOB referenced by sqlite3_blob_open() may be read using the
6455 ** [sqlite3_blob_read()] interface and modified by using
6456 ** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a
6457 ** different row of the same table using the [sqlite3_blob_reopen()]
6458 ** interface. However, the column, table, or database of a [BLOB handle]
6459 ** cannot be changed after the [BLOB handle] is opened.
6461 ** ^(If the row that a BLOB handle points to is modified by an
6462 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
6463 ** then the BLOB handle is marked as "expired".
6464 ** This is true if any column of the row is changed, even a column
6465 ** other than the one the BLOB handle is open on.)^
6466 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
6467 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
6468 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
6469 ** rolled back by the expiration of the BLOB. Such changes will eventually
6470 ** commit if the transaction continues to completion.)^
6472 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
6473 ** the opened blob. ^The size of a blob may not be changed by this
6474 ** interface. Use the [UPDATE] SQL command to change the size of a
6477 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
6478 ** and the built-in [zeroblob] SQL function may be used to create a
6479 ** zero-filled blob to read or write using the incremental-blob interface.
6481 ** To avoid a resource leak, every open [BLOB handle] should eventually
6482 ** be released by a call to [sqlite3_blob_close()].
6484 ** See also: [sqlite3_blob_close()],
6485 ** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
6486 ** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
6488 SQLITE_API int sqlite3_blob_open(
6492 const char *zColumn,
6495 sqlite3_blob **ppBlob
6499 ** CAPI3REF: Move a BLOB Handle to a New Row
6500 ** METHOD: sqlite3_blob
6502 ** ^This function is used to move an existing [BLOB handle] so that it points
6503 ** to a different row of the same database table. ^The new row is identified
6504 ** by the rowid value passed as the second argument. Only the row can be
6505 ** changed. ^The database, table and column on which the blob handle is open
6506 ** remain the same. Moving an existing [BLOB handle] to a new row is
6507 ** faster than closing the existing handle and opening a new one.
6509 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
6510 ** it must exist and there must be either a blob or text value stored in
6511 ** the nominated column.)^ ^If the new row is not present in the table, or if
6512 ** it does not contain a blob or text value, or if another error occurs, an
6513 ** SQLite error code is returned and the blob handle is considered aborted.
6514 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
6515 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
6516 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
6517 ** always returns zero.
6519 ** ^This function sets the database handle error code and message.
6521 SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
6524 ** CAPI3REF: Close A BLOB Handle
6525 ** DESTRUCTOR: sqlite3_blob
6527 ** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
6528 ** unconditionally. Even if this routine returns an error code, the
6529 ** handle is still closed.)^
6531 ** ^If the blob handle being closed was opened for read-write access, and if
6532 ** the database is in auto-commit mode and there are no other open read-write
6533 ** blob handles or active write statements, the current transaction is
6534 ** committed. ^If an error occurs while committing the transaction, an error
6535 ** code is returned and the transaction rolled back.
6537 ** Calling this function with an argument that is not a NULL pointer or an
6538 ** open blob handle results in undefined behaviour. ^Calling this routine
6539 ** with a null pointer (such as would be returned by a failed call to
6540 ** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
6541 ** is passed a valid open blob handle, the values returned by the
6542 ** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
6544 SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
6547 ** CAPI3REF: Return The Size Of An Open BLOB
6548 ** METHOD: sqlite3_blob
6550 ** ^Returns the size in bytes of the BLOB accessible via the
6551 ** successfully opened [BLOB handle] in its only argument. ^The
6552 ** incremental blob I/O routines can only read or overwriting existing
6553 ** blob content; they cannot change the size of a blob.
6555 ** This routine only works on a [BLOB handle] which has been created
6556 ** by a prior successful call to [sqlite3_blob_open()] and which has not
6557 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6558 ** to this routine results in undefined and probably undesirable behavior.
6560 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
6563 ** CAPI3REF: Read Data From A BLOB Incrementally
6564 ** METHOD: sqlite3_blob
6566 ** ^(This function is used to read data from an open [BLOB handle] into a
6567 ** caller-supplied buffer. N bytes of data are copied into buffer Z
6568 ** from the open BLOB, starting at offset iOffset.)^
6570 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
6571 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
6572 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
6573 ** ^The size of the blob (and hence the maximum value of N+iOffset)
6574 ** can be determined using the [sqlite3_blob_bytes()] interface.
6576 ** ^An attempt to read from an expired [BLOB handle] fails with an
6577 ** error code of [SQLITE_ABORT].
6579 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
6580 ** Otherwise, an [error code] or an [extended error code] is returned.)^
6582 ** This routine only works on a [BLOB handle] which has been created
6583 ** by a prior successful call to [sqlite3_blob_open()] and which has not
6584 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6585 ** to this routine results in undefined and probably undesirable behavior.
6587 ** See also: [sqlite3_blob_write()].
6589 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
6592 ** CAPI3REF: Write Data Into A BLOB Incrementally
6593 ** METHOD: sqlite3_blob
6595 ** ^(This function is used to write data into an open [BLOB handle] from a
6596 ** caller-supplied buffer. N bytes of data are copied from the buffer Z
6597 ** into the open BLOB, starting at offset iOffset.)^
6599 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
6600 ** Otherwise, an [error code] or an [extended error code] is returned.)^
6601 ** ^Unless SQLITE_MISUSE is returned, this function sets the
6602 ** [database connection] error code and message accessible via
6603 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6605 ** ^If the [BLOB handle] passed as the first argument was not opened for
6606 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
6607 ** this function returns [SQLITE_READONLY].
6609 ** This function may only modify the contents of the BLOB; it is
6610 ** not possible to increase the size of a BLOB using this API.
6611 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
6612 ** [SQLITE_ERROR] is returned and no data is written. The size of the
6613 ** BLOB (and hence the maximum value of N+iOffset) can be determined
6614 ** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
6615 ** than zero [SQLITE_ERROR] is returned and no data is written.
6617 ** ^An attempt to write to an expired [BLOB handle] fails with an
6618 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
6619 ** before the [BLOB handle] expired are not rolled back by the
6620 ** expiration of the handle, though of course those changes might
6621 ** have been overwritten by the statement that expired the BLOB handle
6622 ** or by other independent statements.
6624 ** This routine only works on a [BLOB handle] which has been created
6625 ** by a prior successful call to [sqlite3_blob_open()] and which has not
6626 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6627 ** to this routine results in undefined and probably undesirable behavior.
6629 ** See also: [sqlite3_blob_read()].
6631 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
6634 ** CAPI3REF: Virtual File System Objects
6636 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
6637 ** that SQLite uses to interact
6638 ** with the underlying operating system. Most SQLite builds come with a
6639 ** single default VFS that is appropriate for the host computer.
6640 ** New VFSes can be registered and existing VFSes can be unregistered.
6641 ** The following interfaces are provided.
6643 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
6644 ** ^Names are case sensitive.
6645 ** ^Names are zero-terminated UTF-8 strings.
6646 ** ^If there is no match, a NULL pointer is returned.
6647 ** ^If zVfsName is NULL then the default VFS is returned.
6649 ** ^New VFSes are registered with sqlite3_vfs_register().
6650 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
6651 ** ^The same VFS can be registered multiple times without injury.
6652 ** ^To make an existing VFS into the default VFS, register it again
6653 ** with the makeDflt flag set. If two different VFSes with the
6654 ** same name are registered, the behavior is undefined. If a
6655 ** VFS is registered with a name that is NULL or an empty string,
6656 ** then the behavior is undefined.
6658 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
6659 ** ^(If the default VFS is unregistered, another VFS is chosen as
6660 ** the default. The choice for the new VFS is arbitrary.)^
6662 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
6663 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
6664 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
6667 ** CAPI3REF: Mutexes
6669 ** The SQLite core uses these routines for thread
6670 ** synchronization. Though they are intended for internal
6671 ** use by SQLite, code that links against SQLite is
6672 ** permitted to use any of these routines.
6674 ** The SQLite source code contains multiple implementations
6675 ** of these mutex routines. An appropriate implementation
6676 ** is selected automatically at compile-time. The following
6677 ** implementations are available in the SQLite core:
6680 ** <li> SQLITE_MUTEX_PTHREADS
6681 ** <li> SQLITE_MUTEX_W32
6682 ** <li> SQLITE_MUTEX_NOOP
6685 ** The SQLITE_MUTEX_NOOP implementation is a set of routines
6686 ** that does no real locking and is appropriate for use in
6687 ** a single-threaded application. The SQLITE_MUTEX_PTHREADS and
6688 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
6691 ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
6692 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
6693 ** implementation is included with the library. In this case the
6694 ** application must supply a custom mutex implementation using the
6695 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
6696 ** before calling sqlite3_initialize() or any other public sqlite3_
6697 ** function that calls sqlite3_initialize().
6699 ** ^The sqlite3_mutex_alloc() routine allocates a new
6700 ** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
6701 ** routine returns NULL if it is unable to allocate the requested
6702 ** mutex. The argument to sqlite3_mutex_alloc() must one of these
6703 ** integer constants:
6706 ** <li> SQLITE_MUTEX_FAST
6707 ** <li> SQLITE_MUTEX_RECURSIVE
6708 ** <li> SQLITE_MUTEX_STATIC_MASTER
6709 ** <li> SQLITE_MUTEX_STATIC_MEM
6710 ** <li> SQLITE_MUTEX_STATIC_OPEN
6711 ** <li> SQLITE_MUTEX_STATIC_PRNG
6712 ** <li> SQLITE_MUTEX_STATIC_LRU
6713 ** <li> SQLITE_MUTEX_STATIC_PMEM
6714 ** <li> SQLITE_MUTEX_STATIC_APP1
6715 ** <li> SQLITE_MUTEX_STATIC_APP2
6716 ** <li> SQLITE_MUTEX_STATIC_APP3
6717 ** <li> SQLITE_MUTEX_STATIC_VFS1
6718 ** <li> SQLITE_MUTEX_STATIC_VFS2
6719 ** <li> SQLITE_MUTEX_STATIC_VFS3
6722 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
6723 ** cause sqlite3_mutex_alloc() to create
6724 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
6725 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
6726 ** The mutex implementation does not need to make a distinction
6727 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
6728 ** not want to. SQLite will only request a recursive mutex in
6729 ** cases where it really needs one. If a faster non-recursive mutex
6730 ** implementation is available on the host platform, the mutex subsystem
6731 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
6733 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
6734 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
6735 ** a pointer to a static preexisting mutex. ^Nine static mutexes are
6736 ** used by the current version of SQLite. Future versions of SQLite
6737 ** may add additional static mutexes. Static mutexes are for internal
6738 ** use by SQLite only. Applications that use SQLite mutexes should
6739 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
6740 ** SQLITE_MUTEX_RECURSIVE.
6742 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
6743 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
6744 ** returns a different mutex on every call. ^For the static
6745 ** mutex types, the same mutex is returned on every call that has
6746 ** the same type number.
6748 ** ^The sqlite3_mutex_free() routine deallocates a previously
6749 ** allocated dynamic mutex. Attempting to deallocate a static
6750 ** mutex results in undefined behavior.
6752 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
6753 ** to enter a mutex. ^If another thread is already within the mutex,
6754 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
6755 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
6756 ** upon successful entry. ^(Mutexes created using
6757 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
6758 ** In such cases, the
6759 ** mutex must be exited an equal number of times before another thread
6760 ** can enter.)^ If the same thread tries to enter any mutex other
6761 ** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
6763 ** ^(Some systems (for example, Windows 95) do not support the operation
6764 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
6765 ** will always return SQLITE_BUSY. The SQLite core only ever uses
6766 ** sqlite3_mutex_try() as an optimization so this is acceptable
6769 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
6770 ** previously entered by the same thread. The behavior
6771 ** is undefined if the mutex is not currently entered by the
6772 ** calling thread or is not currently allocated.
6774 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
6775 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
6776 ** behave as no-ops.
6778 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
6780 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
6781 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
6782 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
6783 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
6784 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
6787 ** CAPI3REF: Mutex Methods Object
6789 ** An instance of this structure defines the low-level routines
6790 ** used to allocate and use mutexes.
6792 ** Usually, the default mutex implementations provided by SQLite are
6793 ** sufficient, however the application has the option of substituting a custom
6794 ** implementation for specialized deployments or systems for which SQLite
6795 ** does not provide a suitable implementation. In this case, the application
6796 ** creates and populates an instance of this structure to pass
6797 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
6798 ** Additionally, an instance of this structure can be used as an
6799 ** output variable when querying the system for the current mutex
6800 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
6802 ** ^The xMutexInit method defined by this structure is invoked as
6803 ** part of system initialization by the sqlite3_initialize() function.
6804 ** ^The xMutexInit routine is called by SQLite exactly once for each
6805 ** effective call to [sqlite3_initialize()].
6807 ** ^The xMutexEnd method defined by this structure is invoked as
6808 ** part of system shutdown by the sqlite3_shutdown() function. The
6809 ** implementation of this method is expected to release all outstanding
6810 ** resources obtained by the mutex methods implementation, especially
6811 ** those obtained by the xMutexInit method. ^The xMutexEnd()
6812 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
6814 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
6815 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
6816 ** xMutexNotheld) implement the following interfaces (respectively):
6819 ** <li> [sqlite3_mutex_alloc()] </li>
6820 ** <li> [sqlite3_mutex_free()] </li>
6821 ** <li> [sqlite3_mutex_enter()] </li>
6822 ** <li> [sqlite3_mutex_try()] </li>
6823 ** <li> [sqlite3_mutex_leave()] </li>
6824 ** <li> [sqlite3_mutex_held()] </li>
6825 ** <li> [sqlite3_mutex_notheld()] </li>
6828 ** The only difference is that the public sqlite3_XXX functions enumerated
6829 ** above silently ignore any invocations that pass a NULL pointer instead
6830 ** of a valid mutex handle. The implementations of the methods defined
6831 ** by this structure are not required to handle this case, the results
6832 ** of passing a NULL pointer instead of a valid mutex handle are undefined
6833 ** (i.e. it is acceptable to provide an implementation that segfaults if
6834 ** it is passed a NULL pointer).
6836 ** The xMutexInit() method must be threadsafe. It must be harmless to
6837 ** invoke xMutexInit() multiple times within the same process and without
6838 ** intervening calls to xMutexEnd(). Second and subsequent calls to
6839 ** xMutexInit() must be no-ops.
6841 ** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
6842 ** and its associates). Similarly, xMutexAlloc() must not use SQLite memory
6843 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
6844 ** memory allocation for a fast or recursive mutex.
6846 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
6847 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
6848 ** If xMutexInit fails in any way, it is expected to clean up after itself
6849 ** prior to returning.
6851 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
6852 struct sqlite3_mutex_methods {
6853 int (*xMutexInit)(void);
6854 int (*xMutexEnd)(void);
6855 sqlite3_mutex *(*xMutexAlloc)(int);
6856 void (*xMutexFree)(sqlite3_mutex *);
6857 void (*xMutexEnter)(sqlite3_mutex *);
6858 int (*xMutexTry)(sqlite3_mutex *);
6859 void (*xMutexLeave)(sqlite3_mutex *);
6860 int (*xMutexHeld)(sqlite3_mutex *);
6861 int (*xMutexNotheld)(sqlite3_mutex *);
6865 ** CAPI3REF: Mutex Verification Routines
6867 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
6868 ** are intended for use inside assert() statements. The SQLite core
6869 ** never uses these routines except inside an assert() and applications
6870 ** are advised to follow the lead of the core. The SQLite core only
6871 ** provides implementations for these routines when it is compiled
6872 ** with the SQLITE_DEBUG flag. External mutex implementations
6873 ** are only required to provide these routines if SQLITE_DEBUG is
6874 ** defined and if NDEBUG is not defined.
6876 ** These routines should return true if the mutex in their argument
6877 ** is held or not held, respectively, by the calling thread.
6879 ** The implementation is not required to provide versions of these
6880 ** routines that actually work. If the implementation does not provide working
6881 ** versions of these routines, it should at least provide stubs that always
6882 ** return true so that one does not get spurious assertion failures.
6884 ** If the argument to sqlite3_mutex_held() is a NULL pointer then
6885 ** the routine should return 1. This seems counter-intuitive since
6886 ** clearly the mutex cannot be held if it does not exist. But
6887 ** the reason the mutex does not exist is because the build is not
6888 ** using mutexes. And we do not want the assert() containing the
6889 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
6890 ** the appropriate thing to do. The sqlite3_mutex_notheld()
6891 ** interface should also return 1 when given a NULL pointer.
6894 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
6895 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
6899 ** CAPI3REF: Mutex Types
6901 ** The [sqlite3_mutex_alloc()] interface takes a single argument
6902 ** which is one of these integer constants.
6904 ** The set of static mutexes may change from one SQLite release to the
6905 ** next. Applications that override the built-in mutex logic must be
6906 ** prepared to accommodate additional static mutexes.
6908 #define SQLITE_MUTEX_FAST 0
6909 #define SQLITE_MUTEX_RECURSIVE 1
6910 #define SQLITE_MUTEX_STATIC_MASTER 2
6911 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
6912 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
6913 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
6914 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */
6915 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
6916 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
6917 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
6918 #define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */
6919 #define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */
6920 #define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */
6921 #define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */
6922 #define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */
6923 #define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */
6926 ** CAPI3REF: Retrieve the mutex for a database connection
6929 ** ^This interface returns a pointer the [sqlite3_mutex] object that
6930 ** serializes access to the [database connection] given in the argument
6931 ** when the [threading mode] is Serialized.
6932 ** ^If the [threading mode] is Single-thread or Multi-thread then this
6933 ** routine returns a NULL pointer.
6935 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
6938 ** CAPI3REF: Low-Level Control Of Database Files
6941 ** ^The [sqlite3_file_control()] interface makes a direct call to the
6942 ** xFileControl method for the [sqlite3_io_methods] object associated
6943 ** with a particular database identified by the second argument. ^The
6944 ** name of the database is "main" for the main database or "temp" for the
6945 ** TEMP database, or the name that appears after the AS keyword for
6946 ** databases that are added using the [ATTACH] SQL command.
6947 ** ^A NULL pointer can be used in place of "main" to refer to the
6948 ** main database file.
6949 ** ^The third and fourth parameters to this routine
6950 ** are passed directly through to the second and third parameters of
6951 ** the xFileControl method. ^The return value of the xFileControl
6952 ** method becomes the return value of this routine.
6954 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
6955 ** a pointer to the underlying [sqlite3_file] object to be written into
6956 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER
6957 ** case is a short-circuit path which does not actually invoke the
6958 ** underlying sqlite3_io_methods.xFileControl method.
6960 ** ^If the second parameter (zDbName) does not match the name of any
6961 ** open database file, then SQLITE_ERROR is returned. ^This error
6962 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
6963 ** or [sqlite3_errmsg()]. The underlying xFileControl method might
6964 ** also return SQLITE_ERROR. There is no way to distinguish between
6965 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
6966 ** xFileControl method.
6968 ** See also: [SQLITE_FCNTL_LOCKSTATE]
6970 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
6973 ** CAPI3REF: Testing Interface
6975 ** ^The sqlite3_test_control() interface is used to read out internal
6976 ** state of SQLite and to inject faults into SQLite for testing
6977 ** purposes. ^The first parameter is an operation code that determines
6978 ** the number, meaning, and operation of all subsequent parameters.
6980 ** This interface is not for use by applications. It exists solely
6981 ** for verifying the correct operation of the SQLite library. Depending
6982 ** on how the SQLite library is compiled, this interface might not exist.
6984 ** The details of the operation codes, their meanings, the parameters
6985 ** they take, and what they do are all subject to change without notice.
6986 ** Unlike most of the SQLite API, this function is not guaranteed to
6987 ** operate consistently from one release to the next.
6989 SQLITE_API int sqlite3_test_control(int op, ...);
6992 ** CAPI3REF: Testing Interface Operation Codes
6994 ** These constants are the valid operation code parameters used
6995 ** as the first argument to [sqlite3_test_control()].
6997 ** These parameters and their meanings are subject to change
6998 ** without notice. These values are for testing purposes only.
6999 ** Applications should not use any of these parameters or the
7000 ** [sqlite3_test_control()] interface.
7002 #define SQLITE_TESTCTRL_FIRST 5
7003 #define SQLITE_TESTCTRL_PRNG_SAVE 5
7004 #define SQLITE_TESTCTRL_PRNG_RESTORE 6
7005 #define SQLITE_TESTCTRL_PRNG_RESET 7
7006 #define SQLITE_TESTCTRL_BITVEC_TEST 8
7007 #define SQLITE_TESTCTRL_FAULT_INSTALL 9
7008 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
7009 #define SQLITE_TESTCTRL_PENDING_BYTE 11
7010 #define SQLITE_TESTCTRL_ASSERT 12
7011 #define SQLITE_TESTCTRL_ALWAYS 13
7012 #define SQLITE_TESTCTRL_RESERVE 14
7013 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
7014 #define SQLITE_TESTCTRL_ISKEYWORD 16
7015 #define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */
7016 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
7017 #define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */
7018 #define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19
7019 #define SQLITE_TESTCTRL_NEVER_CORRUPT 20
7020 #define SQLITE_TESTCTRL_VDBE_COVERAGE 21
7021 #define SQLITE_TESTCTRL_BYTEORDER 22
7022 #define SQLITE_TESTCTRL_ISINIT 23
7023 #define SQLITE_TESTCTRL_SORTER_MMAP 24
7024 #define SQLITE_TESTCTRL_IMPOSTER 25
7025 #define SQLITE_TESTCTRL_LAST 25
7028 ** CAPI3REF: SQLite Runtime Status
7030 ** ^These interfaces are used to retrieve runtime status information
7031 ** about the performance of SQLite, and optionally to reset various
7032 ** highwater marks. ^The first argument is an integer code for
7033 ** the specific parameter to measure. ^(Recognized integer codes
7034 ** are of the form [status parameters | SQLITE_STATUS_...].)^
7035 ** ^The current value of the parameter is returned into *pCurrent.
7036 ** ^The highest recorded value is returned in *pHighwater. ^If the
7037 ** resetFlag is true, then the highest record value is reset after
7038 ** *pHighwater is written. ^(Some parameters do not record the highest
7039 ** value. For those parameters
7040 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
7041 ** ^(Other parameters record only the highwater mark and not the current
7042 ** value. For these latter parameters nothing is written into *pCurrent.)^
7044 ** ^The sqlite3_status() and sqlite3_status64() routines return
7045 ** SQLITE_OK on success and a non-zero [error code] on failure.
7047 ** If either the current value or the highwater mark is too large to
7048 ** be represented by a 32-bit integer, then the values returned by
7049 ** sqlite3_status() are undefined.
7051 ** See also: [sqlite3_db_status()]
7053 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
7054 SQLITE_API int sqlite3_status64(
7056 sqlite3_int64 *pCurrent,
7057 sqlite3_int64 *pHighwater,
7063 ** CAPI3REF: Status Parameters
7064 ** KEYWORDS: {status parameters}
7066 ** These integer constants designate various run-time status parameters
7067 ** that can be returned by [sqlite3_status()].
7070 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
7071 ** <dd>This parameter is the current amount of memory checked out
7072 ** using [sqlite3_malloc()], either directly or indirectly. The
7073 ** figure includes calls made to [sqlite3_malloc()] by the application
7074 ** and internal memory usage by the SQLite library. Auxiliary page-cache
7075 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
7076 ** this parameter. The amount returned is the sum of the allocation
7077 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
7079 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
7080 ** <dd>This parameter records the largest memory allocation request
7081 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
7082 ** internal equivalents). Only the value returned in the
7083 ** *pHighwater parameter to [sqlite3_status()] is of interest.
7084 ** The value written into the *pCurrent parameter is undefined.</dd>)^
7086 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
7087 ** <dd>This parameter records the number of separate memory allocations
7088 ** currently checked out.</dd>)^
7090 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
7091 ** <dd>This parameter returns the number of pages used out of the
7092 ** [pagecache memory allocator] that was configured using
7093 ** [SQLITE_CONFIG_PAGECACHE]. The
7094 ** value returned is in pages, not in bytes.</dd>)^
7096 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
7097 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
7098 ** <dd>This parameter returns the number of bytes of page cache
7099 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
7100 ** buffer and where forced to overflow to [sqlite3_malloc()]. The
7101 ** returned value includes allocations that overflowed because they
7102 ** where too large (they were larger than the "sz" parameter to
7103 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
7104 ** no space was left in the page cache.</dd>)^
7106 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
7107 ** <dd>This parameter records the largest memory allocation request
7108 ** handed to [pagecache memory allocator]. Only the value returned in the
7109 ** *pHighwater parameter to [sqlite3_status()] is of interest.
7110 ** The value written into the *pCurrent parameter is undefined.</dd>)^
7112 ** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
7113 ** <dd>No longer used.</dd>
7115 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
7116 ** <dd>No longer used.</dd>
7118 ** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
7119 ** <dd>No longer used.</dd>
7121 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
7122 ** <dd>The *pHighwater parameter records the deepest parser stack.
7123 ** The *pCurrent value is undefined. The *pHighwater value is only
7124 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
7127 ** New status parameters may be added from time to time.
7129 #define SQLITE_STATUS_MEMORY_USED 0
7130 #define SQLITE_STATUS_PAGECACHE_USED 1
7131 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
7132 #define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */
7133 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */
7134 #define SQLITE_STATUS_MALLOC_SIZE 5
7135 #define SQLITE_STATUS_PARSER_STACK 6
7136 #define SQLITE_STATUS_PAGECACHE_SIZE 7
7137 #define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */
7138 #define SQLITE_STATUS_MALLOC_COUNT 9
7141 ** CAPI3REF: Database Connection Status
7144 ** ^This interface is used to retrieve runtime status information
7145 ** about a single [database connection]. ^The first argument is the
7146 ** database connection object to be interrogated. ^The second argument
7147 ** is an integer constant, taken from the set of
7148 ** [SQLITE_DBSTATUS options], that
7149 ** determines the parameter to interrogate. The set of
7150 ** [SQLITE_DBSTATUS options] is likely
7151 ** to grow in future releases of SQLite.
7153 ** ^The current value of the requested parameter is written into *pCur
7154 ** and the highest instantaneous value is written into *pHiwtr. ^If
7155 ** the resetFlg is true, then the highest instantaneous value is
7156 ** reset back down to the current value.
7158 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
7159 ** non-zero [error code] on failure.
7161 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
7163 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
7166 ** CAPI3REF: Status Parameters for database connections
7167 ** KEYWORDS: {SQLITE_DBSTATUS options}
7169 ** These constants are the available integer "verbs" that can be passed as
7170 ** the second argument to the [sqlite3_db_status()] interface.
7172 ** New verbs may be added in future releases of SQLite. Existing verbs
7173 ** might be discontinued. Applications should check the return code from
7174 ** [sqlite3_db_status()] to make sure that the call worked.
7175 ** The [sqlite3_db_status()] interface will return a non-zero error code
7176 ** if a discontinued or unsupported verb is invoked.
7179 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
7180 ** <dd>This parameter returns the number of lookaside memory slots currently
7181 ** checked out.</dd>)^
7183 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
7184 ** <dd>This parameter returns the number malloc attempts that were
7185 ** satisfied using lookaside memory. Only the high-water value is meaningful;
7186 ** the current value is always zero.)^
7188 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
7189 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
7190 ** <dd>This parameter returns the number malloc attempts that might have
7191 ** been satisfied using lookaside memory but failed due to the amount of
7192 ** memory requested being larger than the lookaside slot size.
7193 ** Only the high-water value is meaningful;
7194 ** the current value is always zero.)^
7196 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
7197 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
7198 ** <dd>This parameter returns the number malloc attempts that might have
7199 ** been satisfied using lookaside memory but failed due to all lookaside
7200 ** memory already being in use.
7201 ** Only the high-water value is meaningful;
7202 ** the current value is always zero.)^
7204 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
7205 ** <dd>This parameter returns the approximate number of bytes of heap
7206 ** memory used by all pager caches associated with the database connection.)^
7207 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
7209 ** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
7210 ** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
7211 ** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
7212 ** pager cache is shared between two or more connections the bytes of heap
7213 ** memory used by that pager cache is divided evenly between the attached
7214 ** connections.)^ In other words, if none of the pager caches associated
7215 ** with the database connection are shared, this request returns the same
7216 ** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
7217 ** shared, the value returned by this call will be smaller than that returned
7218 ** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
7219 ** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
7221 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
7222 ** <dd>This parameter returns the approximate number of bytes of heap
7223 ** memory used to store the schema for all databases associated
7224 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
7225 ** ^The full amount of memory used by the schemas is reported, even if the
7226 ** schema memory is shared with other database connections due to
7227 ** [shared cache mode] being enabled.
7228 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
7230 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
7231 ** <dd>This parameter returns the approximate number of bytes of heap
7232 ** and lookaside memory used by all prepared statements associated with
7233 ** the database connection.)^
7234 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
7237 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
7238 ** <dd>This parameter returns the number of pager cache hits that have
7239 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
7243 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
7244 ** <dd>This parameter returns the number of pager cache misses that have
7245 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
7249 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
7250 ** <dd>This parameter returns the number of dirty cache entries that have
7251 ** been written to disk. Specifically, the number of pages written to the
7252 ** wal file in wal mode databases, or the number of pages written to the
7253 ** database file in rollback mode databases. Any pages written as part of
7254 ** transaction rollback or database recovery operations are not included.
7255 ** If an IO or other error occurs while writing a page to disk, the effect
7256 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
7257 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
7260 ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
7261 ** <dd>This parameter returns zero for the current value if and only if
7262 ** all foreign key constraints (deferred or immediate) have been
7263 ** resolved.)^ ^The highwater mark is always 0.
7267 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
7268 #define SQLITE_DBSTATUS_CACHE_USED 1
7269 #define SQLITE_DBSTATUS_SCHEMA_USED 2
7270 #define SQLITE_DBSTATUS_STMT_USED 3
7271 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
7272 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
7273 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
7274 #define SQLITE_DBSTATUS_CACHE_HIT 7
7275 #define SQLITE_DBSTATUS_CACHE_MISS 8
7276 #define SQLITE_DBSTATUS_CACHE_WRITE 9
7277 #define SQLITE_DBSTATUS_DEFERRED_FKS 10
7278 #define SQLITE_DBSTATUS_CACHE_USED_SHARED 11
7279 #define SQLITE_DBSTATUS_MAX 11 /* Largest defined DBSTATUS */
7283 ** CAPI3REF: Prepared Statement Status
7284 ** METHOD: sqlite3_stmt
7286 ** ^(Each prepared statement maintains various
7287 ** [SQLITE_STMTSTATUS counters] that measure the number
7288 ** of times it has performed specific operations.)^ These counters can
7289 ** be used to monitor the performance characteristics of the prepared
7290 ** statements. For example, if the number of table steps greatly exceeds
7291 ** the number of table searches or result rows, that would tend to indicate
7292 ** that the prepared statement is using a full table scan rather than
7295 ** ^(This interface is used to retrieve and reset counter values from
7296 ** a [prepared statement]. The first argument is the prepared statement
7297 ** object to be interrogated. The second argument
7298 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
7299 ** to be interrogated.)^
7300 ** ^The current value of the requested counter is returned.
7301 ** ^If the resetFlg is true, then the counter is reset to zero after this
7302 ** interface call returns.
7304 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
7306 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
7309 ** CAPI3REF: Status Parameters for prepared statements
7310 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
7312 ** These preprocessor macros define integer codes that name counter
7313 ** values associated with the [sqlite3_stmt_status()] interface.
7314 ** The meanings of the various counters are as follows:
7317 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
7318 ** <dd>^This is the number of times that SQLite has stepped forward in
7319 ** a table as part of a full table scan. Large numbers for this counter
7320 ** may indicate opportunities for performance improvement through
7321 ** careful use of indices.</dd>
7323 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
7324 ** <dd>^This is the number of sort operations that have occurred.
7325 ** A non-zero value in this counter may indicate an opportunity to
7326 ** improvement performance through careful use of indices.</dd>
7328 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
7329 ** <dd>^This is the number of rows inserted into transient indices that
7330 ** were created automatically in order to help joins run faster.
7331 ** A non-zero value in this counter may indicate an opportunity to
7332 ** improvement performance by adding permanent indices that do not
7333 ** need to be reinitialized each time the statement is run.</dd>
7335 ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
7336 ** <dd>^This is the number of virtual machine operations executed
7337 ** by the prepared statement if that number is less than or equal
7338 ** to 2147483647. The number of virtual machine operations can be
7339 ** used as a proxy for the total work done by the prepared statement.
7340 ** If the number of virtual machine operations exceeds 2147483647
7341 ** then the value returned by this statement status code is undefined.
7343 ** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
7344 ** <dd>^This is the number of times that the prepare statement has been
7345 ** automatically regenerated due to schema changes or change to
7346 ** [bound parameters] that might affect the query plan.
7348 ** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
7349 ** <dd>^This is the number of times that the prepared statement has
7350 ** been run. A single "run" for the purposes of this counter is one
7351 ** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
7352 ** The counter is incremented on the first [sqlite3_step()] call of each
7355 ** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
7356 ** <dd>^This is the approximate number of bytes of heap memory
7357 ** used to store the prepared statement. ^This value is not actually
7358 ** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
7359 ** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
7363 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
7364 #define SQLITE_STMTSTATUS_SORT 2
7365 #define SQLITE_STMTSTATUS_AUTOINDEX 3
7366 #define SQLITE_STMTSTATUS_VM_STEP 4
7367 #define SQLITE_STMTSTATUS_REPREPARE 5
7368 #define SQLITE_STMTSTATUS_RUN 6
7369 #define SQLITE_STMTSTATUS_MEMUSED 99
7372 ** CAPI3REF: Custom Page Cache Object
7374 ** The sqlite3_pcache type is opaque. It is implemented by
7375 ** the pluggable module. The SQLite core has no knowledge of
7376 ** its size or internal structure and never deals with the
7377 ** sqlite3_pcache object except by holding and passing pointers
7380 ** See [sqlite3_pcache_methods2] for additional information.
7382 typedef struct sqlite3_pcache sqlite3_pcache;
7385 ** CAPI3REF: Custom Page Cache Object
7387 ** The sqlite3_pcache_page object represents a single page in the
7388 ** page cache. The page cache will allocate instances of this
7389 ** object. Various methods of the page cache use pointers to instances
7390 ** of this object as parameters or as their return value.
7392 ** See [sqlite3_pcache_methods2] for additional information.
7394 typedef struct sqlite3_pcache_page sqlite3_pcache_page;
7395 struct sqlite3_pcache_page {
7396 void *pBuf; /* The content of the page */
7397 void *pExtra; /* Extra information associated with the page */
7401 ** CAPI3REF: Application Defined Page Cache.
7402 ** KEYWORDS: {page cache}
7404 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
7405 ** register an alternative page cache implementation by passing in an
7406 ** instance of the sqlite3_pcache_methods2 structure.)^
7407 ** In many applications, most of the heap memory allocated by
7408 ** SQLite is used for the page cache.
7409 ** By implementing a
7410 ** custom page cache using this API, an application can better control
7411 ** the amount of memory consumed by SQLite, the way in which
7412 ** that memory is allocated and released, and the policies used to
7413 ** determine exactly which parts of a database file are cached and for
7416 ** The alternative page cache mechanism is an
7417 ** extreme measure that is only needed by the most demanding applications.
7418 ** The built-in page cache is recommended for most uses.
7420 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
7421 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
7422 ** the application may discard the parameter after the call to
7423 ** [sqlite3_config()] returns.)^
7425 ** [[the xInit() page cache method]]
7426 ** ^(The xInit() method is called once for each effective
7427 ** call to [sqlite3_initialize()])^
7428 ** (usually only once during the lifetime of the process). ^(The xInit()
7429 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
7430 ** The intent of the xInit() method is to set up global data structures
7431 ** required by the custom page cache implementation.
7432 ** ^(If the xInit() method is NULL, then the
7433 ** built-in default page cache is used instead of the application defined
7436 ** [[the xShutdown() page cache method]]
7437 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
7438 ** It can be used to clean up
7439 ** any outstanding resources before process shutdown, if required.
7440 ** ^The xShutdown() method may be NULL.
7442 ** ^SQLite automatically serializes calls to the xInit method,
7443 ** so the xInit method need not be threadsafe. ^The
7444 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
7445 ** not need to be threadsafe either. All other methods must be threadsafe
7446 ** in multithreaded applications.
7448 ** ^SQLite will never invoke xInit() more than once without an intervening
7449 ** call to xShutdown().
7451 ** [[the xCreate() page cache methods]]
7452 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
7453 ** SQLite will typically create one cache instance for each open database file,
7454 ** though this is not guaranteed. ^The
7455 ** first parameter, szPage, is the size in bytes of the pages that must
7456 ** be allocated by the cache. ^szPage will always a power of two. ^The
7457 ** second parameter szExtra is a number of bytes of extra storage
7458 ** associated with each page cache entry. ^The szExtra parameter will
7459 ** a number less than 250. SQLite will use the
7460 ** extra szExtra bytes on each page to store metadata about the underlying
7461 ** database page on disk. The value passed into szExtra depends
7462 ** on the SQLite version, the target platform, and how SQLite was compiled.
7463 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
7464 ** created will be used to cache database pages of a file stored on disk, or
7465 ** false if it is used for an in-memory database. The cache implementation
7466 ** does not have to do anything special based with the value of bPurgeable;
7467 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
7468 ** never invoke xUnpin() except to deliberately delete a page.
7469 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
7470 ** false will always have the "discard" flag set to true.
7471 ** ^Hence, a cache created with bPurgeable false will
7472 ** never contain any unpinned pages.
7474 ** [[the xCachesize() page cache method]]
7475 ** ^(The xCachesize() method may be called at any time by SQLite to set the
7476 ** suggested maximum cache-size (number of pages stored by) the cache
7477 ** instance passed as the first argument. This is the value configured using
7478 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
7479 ** parameter, the implementation is not required to do anything with this
7480 ** value; it is advisory only.
7482 ** [[the xPagecount() page cache methods]]
7483 ** The xPagecount() method must return the number of pages currently
7484 ** stored in the cache, both pinned and unpinned.
7486 ** [[the xFetch() page cache methods]]
7487 ** The xFetch() method locates a page in the cache and returns a pointer to
7488 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
7489 ** The pBuf element of the returned sqlite3_pcache_page object will be a
7490 ** pointer to a buffer of szPage bytes used to store the content of a
7491 ** single database page. The pExtra element of sqlite3_pcache_page will be
7492 ** a pointer to the szExtra bytes of extra storage that SQLite has requested
7493 ** for each entry in the page cache.
7495 ** The page to be fetched is determined by the key. ^The minimum key value
7496 ** is 1. After it has been retrieved using xFetch, the page is considered
7499 ** If the requested page is already in the page cache, then the page cache
7500 ** implementation must return a pointer to the page buffer with its content
7501 ** intact. If the requested page is not already in the cache, then the
7502 ** cache implementation should use the value of the createFlag
7503 ** parameter to help it determined what action to take:
7505 ** <table border=1 width=85% align=center>
7506 ** <tr><th> createFlag <th> Behavior when page is not already in cache
7507 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
7508 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
7509 ** Otherwise return NULL.
7510 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
7511 ** NULL if allocating a new page is effectively impossible.
7514 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
7515 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
7516 ** failed.)^ In between the to xFetch() calls, SQLite may
7517 ** attempt to unpin one or more cache pages by spilling the content of
7518 ** pinned pages to disk and synching the operating system disk cache.
7520 ** [[the xUnpin() page cache method]]
7521 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
7522 ** as its second argument. If the third parameter, discard, is non-zero,
7523 ** then the page must be evicted from the cache.
7524 ** ^If the discard parameter is
7525 ** zero, then the page may be discarded or retained at the discretion of
7526 ** page cache implementation. ^The page cache implementation
7527 ** may choose to evict unpinned pages at any time.
7529 ** The cache must not perform any reference counting. A single
7530 ** call to xUnpin() unpins the page regardless of the number of prior calls
7533 ** [[the xRekey() page cache methods]]
7534 ** The xRekey() method is used to change the key value associated with the
7535 ** page passed as the second argument. If the cache
7536 ** previously contains an entry associated with newKey, it must be
7537 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
7540 ** When SQLite calls the xTruncate() method, the cache must discard all
7541 ** existing cache entries with page numbers (keys) greater than or equal
7542 ** to the value of the iLimit parameter passed to xTruncate(). If any
7543 ** of these pages are pinned, they are implicitly unpinned, meaning that
7544 ** they can be safely discarded.
7546 ** [[the xDestroy() page cache method]]
7547 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
7548 ** All resources associated with the specified cache should be freed. ^After
7549 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
7550 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
7553 ** [[the xShrink() page cache method]]
7554 ** ^SQLite invokes the xShrink() method when it wants the page cache to
7555 ** free up as much of heap memory as possible. The page cache implementation
7556 ** is not obligated to free any memory, but well-behaved implementations should
7559 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
7560 struct sqlite3_pcache_methods2 {
7563 int (*xInit)(void*);
7564 void (*xShutdown)(void*);
7565 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
7566 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
7567 int (*xPagecount)(sqlite3_pcache*);
7568 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
7569 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
7570 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
7571 unsigned oldKey, unsigned newKey);
7572 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
7573 void (*xDestroy)(sqlite3_pcache*);
7574 void (*xShrink)(sqlite3_pcache*);
7578 ** This is the obsolete pcache_methods object that has now been replaced
7579 ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
7580 ** retained in the header file for backwards compatibility only.
7582 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
7583 struct sqlite3_pcache_methods {
7585 int (*xInit)(void*);
7586 void (*xShutdown)(void*);
7587 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
7588 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
7589 int (*xPagecount)(sqlite3_pcache*);
7590 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
7591 void (*xUnpin)(sqlite3_pcache*, void*, int discard);
7592 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
7593 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
7594 void (*xDestroy)(sqlite3_pcache*);
7599 ** CAPI3REF: Online Backup Object
7601 ** The sqlite3_backup object records state information about an ongoing
7602 ** online backup operation. ^The sqlite3_backup object is created by
7603 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
7604 ** [sqlite3_backup_finish()].
7606 ** See Also: [Using the SQLite Online Backup API]
7608 typedef struct sqlite3_backup sqlite3_backup;
7611 ** CAPI3REF: Online Backup API.
7613 ** The backup API copies the content of one database into another.
7614 ** It is useful either for creating backups of databases or
7615 ** for copying in-memory databases to or from persistent files.
7617 ** See Also: [Using the SQLite Online Backup API]
7619 ** ^SQLite holds a write transaction open on the destination database file
7620 ** for the duration of the backup operation.
7621 ** ^The source database is read-locked only while it is being read;
7622 ** it is not locked continuously for the entire backup operation.
7623 ** ^Thus, the backup may be performed on a live source database without
7624 ** preventing other database connections from
7625 ** reading or writing to the source database while the backup is underway.
7627 ** ^(To perform a backup operation:
7629 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
7631 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
7632 ** the data between the two databases, and finally
7633 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
7634 ** associated with the backup operation.
7636 ** There should be exactly one call to sqlite3_backup_finish() for each
7637 ** successful call to sqlite3_backup_init().
7639 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
7641 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
7642 ** [database connection] associated with the destination database
7643 ** and the database name, respectively.
7644 ** ^The database name is "main" for the main database, "temp" for the
7645 ** temporary database, or the name specified after the AS keyword in
7646 ** an [ATTACH] statement for an attached database.
7647 ** ^The S and M arguments passed to
7648 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
7649 ** and database name of the source database, respectively.
7650 ** ^The source and destination [database connections] (parameters S and D)
7651 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
7654 ** ^A call to sqlite3_backup_init() will fail, returning NULL, if
7655 ** there is already a read or read-write transaction open on the
7656 ** destination database.
7658 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
7659 ** returned and an error code and error message are stored in the
7660 ** destination [database connection] D.
7661 ** ^The error code and message for the failed call to sqlite3_backup_init()
7662 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
7663 ** [sqlite3_errmsg16()] functions.
7664 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
7665 ** [sqlite3_backup] object.
7666 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
7667 ** sqlite3_backup_finish() functions to perform the specified backup
7670 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
7672 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
7673 ** the source and destination databases specified by [sqlite3_backup] object B.
7674 ** ^If N is negative, all remaining source pages are copied.
7675 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
7676 ** are still more pages to be copied, then the function returns [SQLITE_OK].
7677 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
7678 ** from source to destination, then it returns [SQLITE_DONE].
7679 ** ^If an error occurs while running sqlite3_backup_step(B,N),
7680 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
7681 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
7682 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
7683 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
7685 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
7687 ** <li> the destination database was opened read-only, or
7688 ** <li> the destination database is using write-ahead-log journaling
7689 ** and the destination and source page sizes differ, or
7690 ** <li> the destination database is an in-memory database and the
7691 ** destination and source page sizes differ.
7694 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
7695 ** the [sqlite3_busy_handler | busy-handler function]
7696 ** is invoked (if one is specified). ^If the
7697 ** busy-handler returns non-zero before the lock is available, then
7698 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
7699 ** sqlite3_backup_step() can be retried later. ^If the source
7700 ** [database connection]
7701 ** is being used to write to the source database when sqlite3_backup_step()
7702 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
7703 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
7704 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
7705 ** [SQLITE_READONLY] is returned, then
7706 ** there is no point in retrying the call to sqlite3_backup_step(). These
7707 ** errors are considered fatal.)^ The application must accept
7708 ** that the backup operation has failed and pass the backup operation handle
7709 ** to the sqlite3_backup_finish() to release associated resources.
7711 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
7712 ** on the destination file. ^The exclusive lock is not released until either
7713 ** sqlite3_backup_finish() is called or the backup operation is complete
7714 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
7715 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
7716 ** lasts for the duration of the sqlite3_backup_step() call.
7717 ** ^Because the source database is not locked between calls to
7718 ** sqlite3_backup_step(), the source database may be modified mid-way
7719 ** through the backup process. ^If the source database is modified by an
7720 ** external process or via a database connection other than the one being
7721 ** used by the backup operation, then the backup will be automatically
7722 ** restarted by the next call to sqlite3_backup_step(). ^If the source
7723 ** database is modified by the using the same database connection as is used
7724 ** by the backup operation, then the backup database is automatically
7725 ** updated at the same time.
7727 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
7729 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
7730 ** application wishes to abandon the backup operation, the application
7731 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
7732 ** ^The sqlite3_backup_finish() interfaces releases all
7733 ** resources associated with the [sqlite3_backup] object.
7734 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
7735 ** active write-transaction on the destination database is rolled back.
7736 ** The [sqlite3_backup] object is invalid
7737 ** and may not be used following a call to sqlite3_backup_finish().
7739 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
7740 ** sqlite3_backup_step() errors occurred, regardless or whether or not
7741 ** sqlite3_backup_step() completed.
7742 ** ^If an out-of-memory condition or IO error occurred during any prior
7743 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
7744 ** sqlite3_backup_finish() returns the corresponding [error code].
7746 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
7747 ** is not a permanent error and does not affect the return value of
7748 ** sqlite3_backup_finish().
7750 ** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
7751 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
7753 ** ^The sqlite3_backup_remaining() routine returns the number of pages still
7754 ** to be backed up at the conclusion of the most recent sqlite3_backup_step().
7755 ** ^The sqlite3_backup_pagecount() routine returns the total number of pages
7756 ** in the source database at the conclusion of the most recent
7757 ** sqlite3_backup_step().
7758 ** ^(The values returned by these functions are only updated by
7759 ** sqlite3_backup_step(). If the source database is modified in a way that
7760 ** changes the size of the source database or the number of pages remaining,
7761 ** those changes are not reflected in the output of sqlite3_backup_pagecount()
7762 ** and sqlite3_backup_remaining() until after the next
7763 ** sqlite3_backup_step().)^
7765 ** <b>Concurrent Usage of Database Handles</b>
7767 ** ^The source [database connection] may be used by the application for other
7768 ** purposes while a backup operation is underway or being initialized.
7769 ** ^If SQLite is compiled and configured to support threadsafe database
7770 ** connections, then the source database connection may be used concurrently
7771 ** from within other threads.
7773 ** However, the application must guarantee that the destination
7774 ** [database connection] is not passed to any other API (by any thread) after
7775 ** sqlite3_backup_init() is called and before the corresponding call to
7776 ** sqlite3_backup_finish(). SQLite does not currently check to see
7777 ** if the application incorrectly accesses the destination [database connection]
7778 ** and so no error code is reported, but the operations may malfunction
7779 ** nevertheless. Use of the destination database connection while a
7780 ** backup is in progress might also also cause a mutex deadlock.
7782 ** If running in [shared cache mode], the application must
7783 ** guarantee that the shared cache used by the destination database
7784 ** is not accessed while the backup is running. In practice this means
7785 ** that the application must guarantee that the disk file being
7786 ** backed up to is not accessed by any connection within the process,
7787 ** not just the specific connection that was passed to sqlite3_backup_init().
7789 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
7790 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
7791 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
7792 ** APIs are not strictly speaking threadsafe. If they are invoked at the
7793 ** same time as another thread is invoking sqlite3_backup_step() it is
7794 ** possible that they return invalid values.
7796 SQLITE_API sqlite3_backup *sqlite3_backup_init(
7797 sqlite3 *pDest, /* Destination database handle */
7798 const char *zDestName, /* Destination database name */
7799 sqlite3 *pSource, /* Source database handle */
7800 const char *zSourceName /* Source database name */
7802 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
7803 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
7804 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
7805 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
7808 ** CAPI3REF: Unlock Notification
7811 ** ^When running in shared-cache mode, a database operation may fail with
7812 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
7813 ** individual tables within the shared-cache cannot be obtained. See
7814 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
7815 ** ^This API may be used to register a callback that SQLite will invoke
7816 ** when the connection currently holding the required lock relinquishes it.
7817 ** ^This API is only available if the library was compiled with the
7818 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
7820 ** See Also: [Using the SQLite Unlock Notification Feature].
7822 ** ^Shared-cache locks are released when a database connection concludes
7823 ** its current transaction, either by committing it or rolling it back.
7825 ** ^When a connection (known as the blocked connection) fails to obtain a
7826 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
7827 ** identity of the database connection (the blocking connection) that
7828 ** has locked the required resource is stored internally. ^After an
7829 ** application receives an SQLITE_LOCKED error, it may call the
7830 ** sqlite3_unlock_notify() method with the blocked connection handle as
7831 ** the first argument to register for a callback that will be invoked
7832 ** when the blocking connections current transaction is concluded. ^The
7833 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
7834 ** call that concludes the blocking connections transaction.
7836 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
7837 ** there is a chance that the blocking connection will have already
7838 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
7839 ** If this happens, then the specified callback is invoked immediately,
7840 ** from within the call to sqlite3_unlock_notify().)^
7842 ** ^If the blocked connection is attempting to obtain a write-lock on a
7843 ** shared-cache table, and more than one other connection currently holds
7844 ** a read-lock on the same table, then SQLite arbitrarily selects one of
7845 ** the other connections to use as the blocking connection.
7847 ** ^(There may be at most one unlock-notify callback registered by a
7848 ** blocked connection. If sqlite3_unlock_notify() is called when the
7849 ** blocked connection already has a registered unlock-notify callback,
7850 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
7851 ** called with a NULL pointer as its second argument, then any existing
7852 ** unlock-notify callback is canceled. ^The blocked connections
7853 ** unlock-notify callback may also be canceled by closing the blocked
7854 ** connection using [sqlite3_close()].
7856 ** The unlock-notify callback is not reentrant. If an application invokes
7857 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
7858 ** crash or deadlock may be the result.
7860 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
7861 ** returns SQLITE_OK.
7863 ** <b>Callback Invocation Details</b>
7865 ** When an unlock-notify callback is registered, the application provides a
7866 ** single void* pointer that is passed to the callback when it is invoked.
7867 ** However, the signature of the callback function allows SQLite to pass
7868 ** it an array of void* context pointers. The first argument passed to
7869 ** an unlock-notify callback is a pointer to an array of void* pointers,
7870 ** and the second is the number of entries in the array.
7872 ** When a blocking connections transaction is concluded, there may be
7873 ** more than one blocked connection that has registered for an unlock-notify
7874 ** callback. ^If two or more such blocked connections have specified the
7875 ** same callback function, then instead of invoking the callback function
7876 ** multiple times, it is invoked once with the set of void* context pointers
7877 ** specified by the blocked connections bundled together into an array.
7878 ** This gives the application an opportunity to prioritize any actions
7879 ** related to the set of unblocked database connections.
7881 ** <b>Deadlock Detection</b>
7883 ** Assuming that after registering for an unlock-notify callback a
7884 ** database waits for the callback to be issued before taking any further
7885 ** action (a reasonable assumption), then using this API may cause the
7886 ** application to deadlock. For example, if connection X is waiting for
7887 ** connection Y's transaction to be concluded, and similarly connection
7888 ** Y is waiting on connection X's transaction, then neither connection
7889 ** will proceed and the system may remain deadlocked indefinitely.
7891 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
7892 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
7893 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
7894 ** unlock-notify callback is registered. The system is said to be in
7895 ** a deadlocked state if connection A has registered for an unlock-notify
7896 ** callback on the conclusion of connection B's transaction, and connection
7897 ** B has itself registered for an unlock-notify callback when connection
7898 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
7899 ** the system is also considered to be deadlocked if connection B has
7900 ** registered for an unlock-notify callback on the conclusion of connection
7901 ** C's transaction, where connection C is waiting on connection A. ^Any
7902 ** number of levels of indirection are allowed.
7904 ** <b>The "DROP TABLE" Exception</b>
7906 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
7907 ** always appropriate to call sqlite3_unlock_notify(). There is however,
7908 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
7909 ** SQLite checks if there are any currently executing SELECT statements
7910 ** that belong to the same connection. If there are, SQLITE_LOCKED is
7911 ** returned. In this case there is no "blocking connection", so invoking
7912 ** sqlite3_unlock_notify() results in the unlock-notify callback being
7913 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
7914 ** or "DROP INDEX" query, an infinite loop might be the result.
7916 ** One way around this problem is to check the extended error code returned
7917 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
7918 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
7919 ** the special "DROP TABLE/INDEX" case, the extended error code is just
7922 SQLITE_API int sqlite3_unlock_notify(
7923 sqlite3 *pBlocked, /* Waiting connection */
7924 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
7925 void *pNotifyArg /* Argument to pass to xNotify */
7930 ** CAPI3REF: String Comparison
7932 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
7933 ** and extensions to compare the contents of two buffers containing UTF-8
7934 ** strings in a case-independent fashion, using the same definition of "case
7935 ** independence" that SQLite uses internally when comparing identifiers.
7937 SQLITE_API int sqlite3_stricmp(const char *, const char *);
7938 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
7941 ** CAPI3REF: String Globbing
7943 ** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
7944 ** string X matches the [GLOB] pattern P.
7945 ** ^The definition of [GLOB] pattern matching used in
7946 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
7947 ** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function
7948 ** is case sensitive.
7950 ** Note that this routine returns zero on a match and non-zero if the strings
7951 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
7953 ** See also: [sqlite3_strlike()].
7955 SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
7958 ** CAPI3REF: String LIKE Matching
7960 ** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
7961 ** string X matches the [LIKE] pattern P with escape character E.
7962 ** ^The definition of [LIKE] pattern matching used in
7963 ** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
7964 ** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without
7965 ** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
7966 ** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
7967 ** insensitive - equivalent upper and lower case ASCII characters match
7970 ** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
7971 ** only ASCII characters are case folded.
7973 ** Note that this routine returns zero on a match and non-zero if the strings
7974 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
7976 ** See also: [sqlite3_strglob()].
7978 SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
7981 ** CAPI3REF: Error Logging Interface
7983 ** ^The [sqlite3_log()] interface writes a message into the [error log]
7984 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
7985 ** ^If logging is enabled, the zFormat string and subsequent arguments are
7986 ** used with [sqlite3_snprintf()] to generate the final output string.
7988 ** The sqlite3_log() interface is intended for use by extensions such as
7989 ** virtual tables, collating functions, and SQL functions. While there is
7990 ** nothing to prevent an application from calling sqlite3_log(), doing so
7991 ** is considered bad form.
7993 ** The zFormat string must not be NULL.
7995 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
7996 ** will not use dynamically allocated memory. The log message is stored in
7997 ** a fixed-length buffer on the stack. If the log message is longer than
7998 ** a few hundred characters, it will be truncated to the length of the
8001 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
8004 ** CAPI3REF: Write-Ahead Log Commit Hook
8007 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
8008 ** is invoked each time data is committed to a database in wal mode.
8010 ** ^(The callback is invoked by SQLite after the commit has taken place and
8011 ** the associated write-lock on the database released)^, so the implementation
8012 ** may read, write or [checkpoint] the database as required.
8014 ** ^The first parameter passed to the callback function when it is invoked
8015 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
8016 ** registering the callback. ^The second is a copy of the database handle.
8017 ** ^The third parameter is the name of the database that was written to -
8018 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
8019 ** is the number of pages currently in the write-ahead log file,
8020 ** including those that were just committed.
8022 ** The callback function should normally return [SQLITE_OK]. ^If an error
8023 ** code is returned, that error will propagate back up through the
8024 ** SQLite code base to cause the statement that provoked the callback
8025 ** to report an error, though the commit will have still occurred. If the
8026 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
8027 ** that does not correspond to any valid SQLite error code, the results
8030 ** A single database handle may have at most a single write-ahead log callback
8031 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
8032 ** previously registered write-ahead log callback. ^Note that the
8033 ** [sqlite3_wal_autocheckpoint()] interface and the
8034 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
8035 ** overwrite any prior [sqlite3_wal_hook()] settings.
8037 SQLITE_API void *sqlite3_wal_hook(
8039 int(*)(void *,sqlite3*,const char*,int),
8044 ** CAPI3REF: Configure an auto-checkpoint
8047 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
8048 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
8049 ** to automatically [checkpoint]
8050 ** after committing a transaction if there are N or
8051 ** more frames in the [write-ahead log] file. ^Passing zero or
8052 ** a negative value as the nFrame parameter disables automatic
8053 ** checkpoints entirely.
8055 ** ^The callback registered by this function replaces any existing callback
8056 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
8057 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
8058 ** configured by this function.
8060 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
8063 ** ^Checkpoints initiated by this mechanism are
8064 ** [sqlite3_wal_checkpoint_v2|PASSIVE].
8066 ** ^Every new [database connection] defaults to having the auto-checkpoint
8067 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
8068 ** pages. The use of this interface
8069 ** is only necessary if the default setting is found to be suboptimal
8070 ** for a particular application.
8072 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
8075 ** CAPI3REF: Checkpoint a database
8078 ** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
8079 ** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
8081 ** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
8082 ** [write-ahead log] for database X on [database connection] D to be
8083 ** transferred into the database file and for the write-ahead log to
8084 ** be reset. See the [checkpointing] documentation for addition
8087 ** This interface used to be the only way to cause a checkpoint to
8088 ** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
8089 ** interface was added. This interface is retained for backwards
8090 ** compatibility and as a convenience for applications that need to manually
8091 ** start a callback but which do not need the full power (and corresponding
8092 ** complication) of [sqlite3_wal_checkpoint_v2()].
8094 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
8097 ** CAPI3REF: Checkpoint a database
8100 ** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
8101 ** operation on database X of [database connection] D in mode M. Status
8102 ** information is written back into integers pointed to by L and C.)^
8103 ** ^(The M parameter must be a valid [checkpoint mode]:)^
8106 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
8107 ** ^Checkpoint as many frames as possible without waiting for any database
8108 ** readers or writers to finish, then sync the database file if all frames
8109 ** in the log were checkpointed. ^The [busy-handler callback]
8110 ** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
8111 ** ^On the other hand, passive mode might leave the checkpoint unfinished
8112 ** if there are concurrent readers or writers.
8114 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
8115 ** ^This mode blocks (it invokes the
8116 ** [sqlite3_busy_handler|busy-handler callback]) until there is no
8117 ** database writer and all readers are reading from the most recent database
8118 ** snapshot. ^It then checkpoints all frames in the log file and syncs the
8119 ** database file. ^This mode blocks new database writers while it is pending,
8120 ** but new database readers are allowed to continue unimpeded.
8122 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
8123 ** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
8124 ** that after checkpointing the log file it blocks (calls the
8125 ** [busy-handler callback])
8126 ** until all readers are reading from the database file only. ^This ensures
8127 ** that the next writer will restart the log file from the beginning.
8128 ** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
8129 ** database writer attempts while it is pending, but does not impede readers.
8131 ** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
8132 ** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
8133 ** addition that it also truncates the log file to zero bytes just prior
8134 ** to a successful return.
8137 ** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
8138 ** the log file or to -1 if the checkpoint could not run because
8139 ** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
8140 ** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
8141 ** log file (including any that were already checkpointed before the function
8142 ** was called) or to -1 if the checkpoint could not run due to an error or
8143 ** because the database is not in WAL mode. ^Note that upon successful
8144 ** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
8145 ** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
8147 ** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
8148 ** any other process is running a checkpoint operation at the same time, the
8149 ** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
8150 ** busy-handler configured, it will not be invoked in this case.
8152 ** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
8153 ** exclusive "writer" lock on the database file. ^If the writer lock cannot be
8154 ** obtained immediately, and a busy-handler is configured, it is invoked and
8155 ** the writer lock retried until either the busy-handler returns 0 or the lock
8156 ** is successfully obtained. ^The busy-handler is also invoked while waiting for
8157 ** database readers as described above. ^If the busy-handler returns 0 before
8158 ** the writer lock is obtained or while waiting for database readers, the
8159 ** checkpoint operation proceeds from that point in the same way as
8160 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
8161 ** without blocking any further. ^SQLITE_BUSY is returned in this case.
8163 ** ^If parameter zDb is NULL or points to a zero length string, then the
8164 ** specified operation is attempted on all WAL databases [attached] to
8165 ** [database connection] db. In this case the
8166 ** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
8167 ** an SQLITE_BUSY error is encountered when processing one or more of the
8168 ** attached WAL databases, the operation is still attempted on any remaining
8169 ** attached databases and SQLITE_BUSY is returned at the end. ^If any other
8170 ** error occurs while processing an attached database, processing is abandoned
8171 ** and the error code is returned to the caller immediately. ^If no error
8172 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
8173 ** databases, SQLITE_OK is returned.
8175 ** ^If database zDb is the name of an attached database that is not in WAL
8176 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
8177 ** zDb is not NULL (or a zero length string) and is not the name of any
8178 ** attached database, SQLITE_ERROR is returned to the caller.
8180 ** ^Unless it returns SQLITE_MISUSE,
8181 ** the sqlite3_wal_checkpoint_v2() interface
8182 ** sets the error information that is queried by
8183 ** [sqlite3_errcode()] and [sqlite3_errmsg()].
8185 ** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
8188 SQLITE_API int sqlite3_wal_checkpoint_v2(
8189 sqlite3 *db, /* Database handle */
8190 const char *zDb, /* Name of attached database (or NULL) */
8191 int eMode, /* SQLITE_CHECKPOINT_* value */
8192 int *pnLog, /* OUT: Size of WAL log in frames */
8193 int *pnCkpt /* OUT: Total number of frames checkpointed */
8197 ** CAPI3REF: Checkpoint Mode Values
8198 ** KEYWORDS: {checkpoint mode}
8200 ** These constants define all valid values for the "checkpoint mode" passed
8201 ** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
8202 ** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
8203 ** meaning of each of these checkpoint modes.
8205 #define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */
8206 #define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */
8207 #define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */
8208 #define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */
8211 ** CAPI3REF: Virtual Table Interface Configuration
8213 ** This function may be called by either the [xConnect] or [xCreate] method
8214 ** of a [virtual table] implementation to configure
8215 ** various facets of the virtual table interface.
8217 ** If this interface is invoked outside the context of an xConnect or
8218 ** xCreate virtual table method then the behavior is undefined.
8220 ** At present, there is only one option that may be configured using
8221 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options
8222 ** may be added in the future.
8224 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
8227 ** CAPI3REF: Virtual Table Configuration Options
8229 ** These macros define the various options to the
8230 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
8231 ** can use to customize and optimize their behavior.
8234 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
8235 ** <dd>Calls of the form
8236 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
8237 ** where X is an integer. If X is zero, then the [virtual table] whose
8238 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
8239 ** support constraints. In this configuration (which is the default) if
8240 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
8241 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
8242 ** specified as part of the users SQL statement, regardless of the actual
8243 ** ON CONFLICT mode specified.
8245 ** If X is non-zero, then the virtual table implementation guarantees
8246 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
8247 ** any modifications to internal or persistent data structures have been made.
8248 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
8249 ** is able to roll back a statement or database transaction, and abandon
8250 ** or continue processing the current SQL statement as appropriate.
8251 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
8252 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
8255 ** Virtual table implementations that are required to handle OR REPLACE
8256 ** must do so within the [xUpdate] method. If a call to the
8257 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
8258 ** CONFLICT policy is REPLACE, the virtual table implementation should
8259 ** silently replace the appropriate rows within the xUpdate callback and
8260 ** return SQLITE_OK. Or, if this is not possible, it may return
8261 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
8262 ** constraint handling.
8265 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
8268 ** CAPI3REF: Determine The Virtual Table Conflict Policy
8270 ** This function may only be called from within a call to the [xUpdate] method
8271 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
8272 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
8273 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
8274 ** of the SQL statement that triggered the call to the [xUpdate] method of the
8277 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
8280 ** CAPI3REF: Conflict resolution modes
8281 ** KEYWORDS: {conflict resolution mode}
8283 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
8284 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
8285 ** is for the SQL statement being evaluated.
8287 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
8288 ** return value from the [sqlite3_set_authorizer()] callback and that
8289 ** [SQLITE_ABORT] is also a [result code].
8291 #define SQLITE_ROLLBACK 1
8292 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
8293 #define SQLITE_FAIL 3
8294 /* #define SQLITE_ABORT 4 // Also an error code */
8295 #define SQLITE_REPLACE 5
8298 ** CAPI3REF: Prepared Statement Scan Status Opcodes
8299 ** KEYWORDS: {scanstatus options}
8301 ** The following constants can be used for the T parameter to the
8302 ** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a
8303 ** different metric for sqlite3_stmt_scanstatus() to return.
8305 ** When the value returned to V is a string, space to hold that string is
8306 ** managed by the prepared statement S and will be automatically freed when
8310 ** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
8311 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be
8312 ** set to the total number of times that the X-th loop has run.</dd>
8314 ** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
8315 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set
8316 ** to the total number of rows examined by all iterations of the X-th loop.</dd>
8318 ** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
8319 ** <dd>^The "double" variable pointed to by the T parameter will be set to the
8320 ** query planner's estimate for the average number of rows output from each
8321 ** iteration of the X-th loop. If the query planner's estimates was accurate,
8322 ** then this value will approximate the quotient NVISIT/NLOOP and the
8323 ** product of this value for all prior loops with the same SELECTID will
8324 ** be the NLOOP value for the current loop.
8326 ** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
8327 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
8328 ** to a zero-terminated UTF-8 string containing the name of the index or table
8329 ** used for the X-th loop.
8331 ** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
8332 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
8333 ** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
8334 ** description for the X-th loop.
8336 ** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
8337 ** <dd>^The "int" variable pointed to by the T parameter will be set to the
8338 ** "select-id" for the X-th loop. The select-id identifies which query or
8339 ** subquery the loop is part of. The main query has a select-id of zero.
8340 ** The select-id is the same value as is output in the first column
8341 ** of an [EXPLAIN QUERY PLAN] query.
8344 #define SQLITE_SCANSTAT_NLOOP 0
8345 #define SQLITE_SCANSTAT_NVISIT 1
8346 #define SQLITE_SCANSTAT_EST 2
8347 #define SQLITE_SCANSTAT_NAME 3
8348 #define SQLITE_SCANSTAT_EXPLAIN 4
8349 #define SQLITE_SCANSTAT_SELECTID 5
8352 ** CAPI3REF: Prepared Statement Scan Status
8353 ** METHOD: sqlite3_stmt
8355 ** This interface returns information about the predicted and measured
8356 ** performance for pStmt. Advanced applications can use this
8357 ** interface to compare the predicted and the measured performance and
8358 ** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
8360 ** Since this interface is expected to be rarely used, it is only
8361 ** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
8362 ** compile-time option.
8364 ** The "iScanStatusOp" parameter determines which status information to return.
8365 ** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
8366 ** of this interface is undefined.
8367 ** ^The requested measurement is written into a variable pointed to by
8368 ** the "pOut" parameter.
8369 ** Parameter "idx" identifies the specific loop to retrieve statistics for.
8370 ** Loops are numbered starting from zero. ^If idx is out of range - less than
8371 ** zero or greater than or equal to the total number of loops used to implement
8372 ** the statement - a non-zero value is returned and the variable that pOut
8373 ** points to is unchanged.
8375 ** ^Statistics might not be available for all loops in all statements. ^In cases
8376 ** where there exist loops with no available statistics, this function behaves
8377 ** as if the loop did not exist - it returns non-zero and leave the variable
8378 ** that pOut points to unchanged.
8380 ** See also: [sqlite3_stmt_scanstatus_reset()]
8382 SQLITE_API int sqlite3_stmt_scanstatus(
8383 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */
8384 int idx, /* Index of loop to report on */
8385 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */
8386 void *pOut /* Result written here */
8390 ** CAPI3REF: Zero Scan-Status Counters
8391 ** METHOD: sqlite3_stmt
8393 ** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
8395 ** This API is only available if the library is built with pre-processor
8396 ** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
8398 SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
8401 ** CAPI3REF: Flush caches to disk mid-transaction
8403 ** ^If a write-transaction is open on [database connection] D when the
8404 ** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
8405 ** pages in the pager-cache that are not currently in use are written out
8406 ** to disk. A dirty page may be in use if a database cursor created by an
8407 ** active SQL statement is reading from it, or if it is page 1 of a database
8408 ** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)]
8409 ** interface flushes caches for all schemas - "main", "temp", and
8410 ** any [attached] databases.
8412 ** ^If this function needs to obtain extra database locks before dirty pages
8413 ** can be flushed to disk, it does so. ^If those locks cannot be obtained
8414 ** immediately and there is a busy-handler callback configured, it is invoked
8415 ** in the usual manner. ^If the required lock still cannot be obtained, then
8416 ** the database is skipped and an attempt made to flush any dirty pages
8417 ** belonging to the next (if any) database. ^If any databases are skipped
8418 ** because locks cannot be obtained, but no other error occurs, this
8419 ** function returns SQLITE_BUSY.
8421 ** ^If any other error occurs while flushing dirty pages to disk (for
8422 ** example an IO error or out-of-memory condition), then processing is
8423 ** abandoned and an SQLite [error code] is returned to the caller immediately.
8425 ** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
8427 ** ^This function does not set the database handle error code or message
8428 ** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
8430 SQLITE_API int sqlite3_db_cacheflush(sqlite3*);
8433 ** CAPI3REF: The pre-update hook.
8435 ** ^These interfaces are only available if SQLite is compiled using the
8436 ** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
8438 ** ^The [sqlite3_preupdate_hook()] interface registers a callback function
8439 ** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
8440 ** on a database table.
8441 ** ^At most one preupdate hook may be registered at a time on a single
8442 ** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
8443 ** the previous setting.
8444 ** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
8445 ** with a NULL pointer as the second parameter.
8446 ** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
8447 ** the first parameter to callbacks.
8449 ** ^The preupdate hook only fires for changes to real database tables; the
8450 ** preupdate hook is not invoked for changes to [virtual tables] or to
8451 ** system tables like sqlite_master or sqlite_stat1.
8453 ** ^The second parameter to the preupdate callback is a pointer to
8454 ** the [database connection] that registered the preupdate hook.
8455 ** ^The third parameter to the preupdate callback is one of the constants
8456 ** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
8457 ** kind of update operation that is about to occur.
8458 ** ^(The fourth parameter to the preupdate callback is the name of the
8459 ** database within the database connection that is being modified. This
8460 ** will be "main" for the main database or "temp" for TEMP tables or
8461 ** the name given after the AS keyword in the [ATTACH] statement for attached
8463 ** ^The fifth parameter to the preupdate callback is the name of the
8464 ** table that is being modified.
8466 ** For an UPDATE or DELETE operation on a [rowid table], the sixth
8467 ** parameter passed to the preupdate callback is the initial [rowid] of the
8468 ** row being modified or deleted. For an INSERT operation on a rowid table,
8469 ** or any operation on a WITHOUT ROWID table, the value of the sixth
8470 ** parameter is undefined. For an INSERT or UPDATE on a rowid table the
8471 ** seventh parameter is the final rowid value of the row being inserted
8472 ** or updated. The value of the seventh parameter passed to the callback
8473 ** function is not defined for operations on WITHOUT ROWID tables, or for
8474 ** INSERT operations on rowid tables.
8476 ** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
8477 ** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
8478 ** provide additional information about a preupdate event. These routines
8479 ** may only be called from within a preupdate callback. Invoking any of
8480 ** these routines from outside of a preupdate callback or with a
8481 ** [database connection] pointer that is different from the one supplied
8482 ** to the preupdate callback results in undefined and probably undesirable
8485 ** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
8486 ** in the row that is being inserted, updated, or deleted.
8488 ** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
8489 ** a [protected sqlite3_value] that contains the value of the Nth column of
8490 ** the table row before it is updated. The N parameter must be between 0
8491 ** and one less than the number of columns or the behavior will be
8492 ** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
8493 ** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
8494 ** behavior is undefined. The [sqlite3_value] that P points to
8495 ** will be destroyed when the preupdate callback returns.
8497 ** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
8498 ** a [protected sqlite3_value] that contains the value of the Nth column of
8499 ** the table row after it is updated. The N parameter must be between 0
8500 ** and one less than the number of columns or the behavior will be
8501 ** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
8502 ** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
8503 ** behavior is undefined. The [sqlite3_value] that P points to
8504 ** will be destroyed when the preupdate callback returns.
8506 ** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
8507 ** callback was invoked as a result of a direct insert, update, or delete
8508 ** operation; or 1 for inserts, updates, or deletes invoked by top-level
8509 ** triggers; or 2 for changes resulting from triggers called by top-level
8510 ** triggers; and so forth.
8512 ** See also: [sqlite3_update_hook()]
8514 #if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
8515 SQLITE_API void *sqlite3_preupdate_hook(
8518 void *pCtx, /* Copy of third arg to preupdate_hook() */
8519 sqlite3 *db, /* Database handle */
8520 int op, /* SQLITE_UPDATE, DELETE or INSERT */
8521 char const *zDb, /* Database name */
8522 char const *zName, /* Table name */
8523 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */
8524 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */
8528 SQLITE_API int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
8529 SQLITE_API int sqlite3_preupdate_count(sqlite3 *);
8530 SQLITE_API int sqlite3_preupdate_depth(sqlite3 *);
8531 SQLITE_API int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
8535 ** CAPI3REF: Low-level system error code
8537 ** ^Attempt to return the underlying operating system error code or error
8538 ** number that caused the most recent I/O error or failure to open a file.
8539 ** The return value is OS-dependent. For example, on unix systems, after
8540 ** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
8541 ** called to get back the underlying "errno" that caused the problem, such
8542 ** as ENOSPC, EAUTH, EISDIR, and so forth.
8544 SQLITE_API int sqlite3_system_errno(sqlite3*);
8547 ** CAPI3REF: Database Snapshot
8548 ** KEYWORDS: {snapshot} {sqlite3_snapshot}
8551 ** An instance of the snapshot object records the state of a [WAL mode]
8552 ** database for some specific point in history.
8554 ** In [WAL mode], multiple [database connections] that are open on the
8555 ** same database file can each be reading a different historical version
8556 ** of the database file. When a [database connection] begins a read
8557 ** transaction, that connection sees an unchanging copy of the database
8558 ** as it existed for the point in time when the transaction first started.
8559 ** Subsequent changes to the database from other connections are not seen
8560 ** by the reader until a new read transaction is started.
8562 ** The sqlite3_snapshot object records state information about an historical
8563 ** version of the database file so that it is possible to later open a new read
8564 ** transaction that sees that historical version of the database rather than
8565 ** the most recent version.
8567 ** The constructor for this object is [sqlite3_snapshot_get()]. The
8568 ** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer
8569 ** to an historical snapshot (if possible). The destructor for
8570 ** sqlite3_snapshot objects is [sqlite3_snapshot_free()].
8572 typedef struct sqlite3_snapshot {
8573 unsigned char hidden[48];
8577 ** CAPI3REF: Record A Database Snapshot
8580 ** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
8581 ** new [sqlite3_snapshot] object that records the current state of
8582 ** schema S in database connection D. ^On success, the
8583 ** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
8584 ** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
8585 ** If there is not already a read-transaction open on schema S when
8586 ** this function is called, one is opened automatically.
8588 ** The following must be true for this function to succeed. If any of
8589 ** the following statements are false when sqlite3_snapshot_get() is
8590 ** called, SQLITE_ERROR is returned. The final value of *P is undefined
8594 ** <li> The database handle must be in [autocommit mode].
8596 ** <li> Schema S of [database connection] D must be a [WAL mode] database.
8598 ** <li> There must not be a write transaction open on schema S of database
8601 ** <li> One or more transactions must have been written to the current wal
8602 ** file since it was created on disk (by any connection). This means
8603 ** that a snapshot cannot be taken on a wal mode database with no wal
8604 ** file immediately after it is first opened. At least one transaction
8605 ** must be written to it first.
8608 ** This function may also return SQLITE_NOMEM. If it is called with the
8609 ** database handle in autocommit mode but fails for some other reason,
8610 ** whether or not a read transaction is opened on schema S is undefined.
8612 ** The [sqlite3_snapshot] object returned from a successful call to
8613 ** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
8614 ** to avoid a memory leak.
8616 ** The [sqlite3_snapshot_get()] interface is only available when the
8617 ** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
8619 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
8621 const char *zSchema,
8622 sqlite3_snapshot **ppSnapshot
8626 ** CAPI3REF: Start a read transaction on an historical snapshot
8629 ** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a
8630 ** read transaction for schema S of
8631 ** [database connection] D such that the read transaction
8632 ** refers to historical [snapshot] P, rather than the most
8633 ** recent change to the database.
8634 ** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success
8635 ** or an appropriate [error code] if it fails.
8637 ** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be
8638 ** the first operation following the [BEGIN] that takes the schema S
8639 ** out of [autocommit mode].
8640 ** ^In other words, schema S must not currently be in
8641 ** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the
8642 ** database connection D must be out of [autocommit mode].
8643 ** ^A [snapshot] will fail to open if it has been overwritten by a
8645 ** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
8646 ** database connection D does not know that the database file for
8647 ** schema S is in [WAL mode]. A database connection might not know
8648 ** that the database file is in [WAL mode] if there has been no prior
8649 ** I/O on that database connection, or if the database entered [WAL mode]
8650 ** after the most recent I/O on the database connection.)^
8651 ** (Hint: Run "[PRAGMA application_id]" against a newly opened
8652 ** database connection in order to make it ready to use snapshots.)
8654 ** The [sqlite3_snapshot_open()] interface is only available when the
8655 ** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
8657 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
8659 const char *zSchema,
8660 sqlite3_snapshot *pSnapshot
8664 ** CAPI3REF: Destroy a snapshot
8667 ** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
8668 ** The application must eventually free every [sqlite3_snapshot] object
8669 ** using this routine to avoid a memory leak.
8671 ** The [sqlite3_snapshot_free()] interface is only available when the
8672 ** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
8674 SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
8677 ** CAPI3REF: Compare the ages of two snapshot handles.
8680 ** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
8681 ** of two valid snapshot handles.
8683 ** If the two snapshot handles are not associated with the same database
8684 ** file, the result of the comparison is undefined.
8686 ** Additionally, the result of the comparison is only valid if both of the
8687 ** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
8688 ** last time the wal file was deleted. The wal file is deleted when the
8689 ** database is changed back to rollback mode or when the number of database
8690 ** clients drops to zero. If either snapshot handle was obtained before the
8691 ** wal file was last deleted, the value returned by this function
8694 ** Otherwise, this API returns a negative value if P1 refers to an older
8695 ** snapshot than P2, zero if the two handles refer to the same database
8696 ** snapshot, and a positive value if P1 is a newer snapshot than P2.
8698 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
8699 sqlite3_snapshot *p1,
8700 sqlite3_snapshot *p2
8704 ** CAPI3REF: Recover snapshots from a wal file
8707 ** If all connections disconnect from a database file but do not perform
8708 ** a checkpoint, the existing wal file is opened along with the database
8709 ** file the next time the database is opened. At this point it is only
8710 ** possible to successfully call sqlite3_snapshot_open() to open the most
8711 ** recent snapshot of the database (the one at the head of the wal file),
8712 ** even though the wal file may contain other valid snapshots for which
8713 ** clients have sqlite3_snapshot handles.
8715 ** This function attempts to scan the wal file associated with database zDb
8716 ** of database handle db and make all valid snapshots available to
8717 ** sqlite3_snapshot_open(). It is an error if there is already a read
8718 ** transaction open on the database, or if the database is not a wal mode
8721 ** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
8723 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
8726 ** Undo the hack that converts floating point types to integer for
8727 ** builds on processors without floating point support.
8729 #ifdef SQLITE_OMIT_FLOATING_POINT
8734 } /* End of the 'extern "C"' block */
8736 #endif /* SQLITE3_H */
8738 /******** Begin file sqlite3rtree.h *********/
8742 ** The author disclaims copyright to this source code. In place of
8743 ** a legal notice, here is a blessing:
8745 ** May you do good and not evil.
8746 ** May you find forgiveness for yourself and forgive others.
8747 ** May you share freely, never taking more than you give.
8749 *************************************************************************
8752 #ifndef _SQLITE3RTREE_H_
8753 #define _SQLITE3RTREE_H_
8760 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
8761 typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
8763 /* The double-precision datatype used by RTree depends on the
8764 ** SQLITE_RTREE_INT_ONLY compile-time option.
8766 #ifdef SQLITE_RTREE_INT_ONLY
8767 typedef sqlite3_int64 sqlite3_rtree_dbl;
8769 typedef double sqlite3_rtree_dbl;
8773 ** Register a geometry callback named zGeom that can be used as part of an
8774 ** R-Tree geometry query as follows:
8776 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
8778 SQLITE_API int sqlite3_rtree_geometry_callback(
8781 int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
8787 ** A pointer to a structure of the following type is passed as the first
8788 ** argument to callbacks registered using rtree_geometry_callback().
8790 struct sqlite3_rtree_geometry {
8791 void *pContext; /* Copy of pContext passed to s_r_g_c() */
8792 int nParam; /* Size of array aParam[] */
8793 sqlite3_rtree_dbl *aParam; /* Parameters passed to SQL geom function */
8794 void *pUser; /* Callback implementation user data */
8795 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */
8799 ** Register a 2nd-generation geometry callback named zScore that can be
8800 ** used as part of an R-Tree geometry query as follows:
8802 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
8804 SQLITE_API int sqlite3_rtree_query_callback(
8806 const char *zQueryFunc,
8807 int (*xQueryFunc)(sqlite3_rtree_query_info*),
8809 void (*xDestructor)(void*)
8814 ** A pointer to a structure of the following type is passed as the
8815 ** argument to scored geometry callback registered using
8816 ** sqlite3_rtree_query_callback().
8818 ** Note that the first 5 fields of this structure are identical to
8819 ** sqlite3_rtree_geometry. This structure is a subclass of
8820 ** sqlite3_rtree_geometry.
8822 struct sqlite3_rtree_query_info {
8823 void *pContext; /* pContext from when function registered */
8824 int nParam; /* Number of function parameters */
8825 sqlite3_rtree_dbl *aParam; /* value of function parameters */
8826 void *pUser; /* callback can use this, if desired */
8827 void (*xDelUser)(void*); /* function to free pUser */
8828 sqlite3_rtree_dbl *aCoord; /* Coordinates of node or entry to check */
8829 unsigned int *anQueue; /* Number of pending entries in the queue */
8830 int nCoord; /* Number of coordinates */
8831 int iLevel; /* Level of current node or entry */
8832 int mxLevel; /* The largest iLevel value in the tree */
8833 sqlite3_int64 iRowid; /* Rowid for current entry */
8834 sqlite3_rtree_dbl rParentScore; /* Score of parent node */
8835 int eParentWithin; /* Visibility of parent node */
8836 int eWithin; /* OUT: Visiblity */
8837 sqlite3_rtree_dbl rScore; /* OUT: Write the score here */
8838 /* The following fields are only available in 3.8.11 and later */
8839 sqlite3_value **apSqlParam; /* Original SQL values of parameters */
8843 ** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
8845 #define NOT_WITHIN 0 /* Object completely outside of query region */
8846 #define PARTLY_WITHIN 1 /* Object partially overlaps query region */
8847 #define FULLY_WITHIN 2 /* Object fully contained within query region */
8851 } /* end of the 'extern "C"' block */
8854 #endif /* ifndef _SQLITE3RTREE_H_ */
8856 /******** End of sqlite3rtree.h *********/
8857 /******** Begin file sqlite3session.h *********/
8859 #if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
8860 #define __SQLITESESSION_H_ 1
8863 ** Make sure we can call this stuff from C++.
8871 ** CAPI3REF: Session Object Handle
8873 typedef struct sqlite3_session sqlite3_session;
8876 ** CAPI3REF: Changeset Iterator Handle
8878 typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
8881 ** CAPI3REF: Create A New Session Object
8883 ** Create a new session object attached to database handle db. If successful,
8884 ** a pointer to the new object is written to *ppSession and SQLITE_OK is
8885 ** returned. If an error occurs, *ppSession is set to NULL and an SQLite
8886 ** error code (e.g. SQLITE_NOMEM) is returned.
8888 ** It is possible to create multiple session objects attached to a single
8891 ** Session objects created using this function should be deleted using the
8892 ** [sqlite3session_delete()] function before the database handle that they
8893 ** are attached to is itself closed. If the database handle is closed before
8894 ** the session object is deleted, then the results of calling any session
8895 ** module function, including [sqlite3session_delete()] on the session object
8898 ** Because the session module uses the [sqlite3_preupdate_hook()] API, it
8899 ** is not possible for an application to register a pre-update hook on a
8900 ** database handle that has one or more session objects attached. Nor is
8901 ** it possible to create a session object attached to a database handle for
8902 ** which a pre-update hook is already defined. The results of attempting
8903 ** either of these things are undefined.
8905 ** The session object will be used to create changesets for tables in
8906 ** database zDb, where zDb is either "main", or "temp", or the name of an
8907 ** attached database. It is not an error if database zDb is not attached
8908 ** to the database when the session object is created.
8910 SQLITE_API int sqlite3session_create(
8911 sqlite3 *db, /* Database handle */
8912 const char *zDb, /* Name of db (e.g. "main") */
8913 sqlite3_session **ppSession /* OUT: New session object */
8917 ** CAPI3REF: Delete A Session Object
8919 ** Delete a session object previously allocated using
8920 ** [sqlite3session_create()]. Once a session object has been deleted, the
8921 ** results of attempting to use pSession with any other session module
8922 ** function are undefined.
8924 ** Session objects must be deleted before the database handle to which they
8925 ** are attached is closed. Refer to the documentation for
8926 ** [sqlite3session_create()] for details.
8928 SQLITE_API void sqlite3session_delete(sqlite3_session *pSession);
8932 ** CAPI3REF: Enable Or Disable A Session Object
8934 ** Enable or disable the recording of changes by a session object. When
8935 ** enabled, a session object records changes made to the database. When
8936 ** disabled - it does not. A newly created session object is enabled.
8937 ** Refer to the documentation for [sqlite3session_changeset()] for further
8938 ** details regarding how enabling and disabling a session object affects
8939 ** the eventual changesets.
8941 ** Passing zero to this function disables the session. Passing a value
8942 ** greater than zero enables it. Passing a value less than zero is a
8943 ** no-op, and may be used to query the current state of the session.
8945 ** The return value indicates the final state of the session object: 0 if
8946 ** the session is disabled, or 1 if it is enabled.
8948 SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable);
8951 ** CAPI3REF: Set Or Clear the Indirect Change Flag
8953 ** Each change recorded by a session object is marked as either direct or
8954 ** indirect. A change is marked as indirect if either:
8957 ** <li> The session object "indirect" flag is set when the change is
8959 ** <li> The change is made by an SQL trigger or foreign key action
8960 ** instead of directly as a result of a users SQL statement.
8963 ** If a single row is affected by more than one operation within a session,
8964 ** then the change is considered indirect if all operations meet the criteria
8965 ** for an indirect change above, or direct otherwise.
8967 ** This function is used to set, clear or query the session object indirect
8968 ** flag. If the second argument passed to this function is zero, then the
8969 ** indirect flag is cleared. If it is greater than zero, the indirect flag
8970 ** is set. Passing a value less than zero does not modify the current value
8971 ** of the indirect flag, and may be used to query the current state of the
8972 ** indirect flag for the specified session object.
8974 ** The return value indicates the final state of the indirect flag: 0 if
8975 ** it is clear, or 1 if it is set.
8977 SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect);
8980 ** CAPI3REF: Attach A Table To A Session Object
8982 ** If argument zTab is not NULL, then it is the name of a table to attach
8983 ** to the session object passed as the first argument. All subsequent changes
8984 ** made to the table while the session object is enabled will be recorded. See
8985 ** documentation for [sqlite3session_changeset()] for further details.
8987 ** Or, if argument zTab is NULL, then changes are recorded for all tables
8988 ** in the database. If additional tables are added to the database (by
8989 ** executing "CREATE TABLE" statements) after this call is made, changes for
8990 ** the new tables are also recorded.
8992 ** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
8993 ** defined as part of their CREATE TABLE statement. It does not matter if the
8994 ** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
8995 ** KEY may consist of a single column, or may be a composite key.
8997 ** It is not an error if the named table does not exist in the database. Nor
8998 ** is it an error if the named table does not have a PRIMARY KEY. However,
8999 ** no changes will be recorded in either of these scenarios.
9001 ** Changes are not recorded for individual rows that have NULL values stored
9002 ** in one or more of their PRIMARY KEY columns.
9004 ** SQLITE_OK is returned if the call completes without error. Or, if an error
9005 ** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
9007 SQLITE_API int sqlite3session_attach(
9008 sqlite3_session *pSession, /* Session object */
9009 const char *zTab /* Table name */
9013 ** CAPI3REF: Set a table filter on a Session Object.
9015 ** The second argument (xFilter) is the "filter callback". For changes to rows
9016 ** in tables that are not attached to the Session object, the filter is called
9017 ** to determine whether changes to the table's rows should be tracked or not.
9018 ** If xFilter returns 0, changes is not tracked. Note that once a table is
9019 ** attached, xFilter will not be called again.
9021 SQLITE_API void sqlite3session_table_filter(
9022 sqlite3_session *pSession, /* Session object */
9024 void *pCtx, /* Copy of third arg to _filter_table() */
9025 const char *zTab /* Table name */
9027 void *pCtx /* First argument passed to xFilter */
9031 ** CAPI3REF: Generate A Changeset From A Session Object
9033 ** Obtain a changeset containing changes to the tables attached to the
9034 ** session object passed as the first argument. If successful,
9035 ** set *ppChangeset to point to a buffer containing the changeset
9036 ** and *pnChangeset to the size of the changeset in bytes before returning
9037 ** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
9038 ** zero and return an SQLite error code.
9040 ** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
9041 ** each representing a change to a single row of an attached table. An INSERT
9042 ** change contains the values of each field of a new database row. A DELETE
9043 ** contains the original values of each field of a deleted database row. An
9044 ** UPDATE change contains the original values of each field of an updated
9045 ** database row along with the updated values for each updated non-primary-key
9046 ** column. It is not possible for an UPDATE change to represent a change that
9047 ** modifies the values of primary key columns. If such a change is made, it
9048 ** is represented in a changeset as a DELETE followed by an INSERT.
9050 ** Changes are not recorded for rows that have NULL values stored in one or
9051 ** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
9052 ** no corresponding change is present in the changesets returned by this
9053 ** function. If an existing row with one or more NULL values stored in
9054 ** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
9055 ** only an INSERT is appears in the changeset. Similarly, if an existing row
9056 ** with non-NULL PRIMARY KEY values is updated so that one or more of its
9057 ** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
9058 ** DELETE change only.
9060 ** The contents of a changeset may be traversed using an iterator created
9061 ** using the [sqlite3changeset_start()] API. A changeset may be applied to
9062 ** a database with a compatible schema using the [sqlite3changeset_apply()]
9065 ** Within a changeset generated by this function, all changes related to a
9066 ** single table are grouped together. In other words, when iterating through
9067 ** a changeset or when applying a changeset to a database, all changes related
9068 ** to a single table are processed before moving on to the next table. Tables
9069 ** are sorted in the same order in which they were attached (or auto-attached)
9070 ** to the sqlite3_session object. The order in which the changes related to
9071 ** a single table are stored is undefined.
9073 ** Following a successful call to this function, it is the responsibility of
9074 ** the caller to eventually free the buffer that *ppChangeset points to using
9075 ** [sqlite3_free()].
9077 ** <h3>Changeset Generation</h3>
9079 ** Once a table has been attached to a session object, the session object
9080 ** records the primary key values of all new rows inserted into the table.
9081 ** It also records the original primary key and other column values of any
9082 ** deleted or updated rows. For each unique primary key value, data is only
9083 ** recorded once - the first time a row with said primary key is inserted,
9084 ** updated or deleted in the lifetime of the session.
9086 ** There is one exception to the previous paragraph: when a row is inserted,
9087 ** updated or deleted, if one or more of its primary key columns contain a
9088 ** NULL value, no record of the change is made.
9090 ** The session object therefore accumulates two types of records - those
9091 ** that consist of primary key values only (created when the user inserts
9092 ** a new record) and those that consist of the primary key values and the
9093 ** original values of other table columns (created when the users deletes
9094 ** or updates a record).
9096 ** When this function is called, the requested changeset is created using
9097 ** both the accumulated records and the current contents of the database
9098 ** file. Specifically:
9101 ** <li> For each record generated by an insert, the database is queried
9102 ** for a row with a matching primary key. If one is found, an INSERT
9103 ** change is added to the changeset. If no such row is found, no change
9104 ** is added to the changeset.
9106 ** <li> For each record generated by an update or delete, the database is
9107 ** queried for a row with a matching primary key. If such a row is
9108 ** found and one or more of the non-primary key fields have been
9109 ** modified from their original values, an UPDATE change is added to
9110 ** the changeset. Or, if no such row is found in the table, a DELETE
9111 ** change is added to the changeset. If there is a row with a matching
9112 ** primary key in the database, but all fields contain their original
9113 ** values, no change is added to the changeset.
9116 ** This means, amongst other things, that if a row is inserted and then later
9117 ** deleted while a session object is active, neither the insert nor the delete
9118 ** will be present in the changeset. Or if a row is deleted and then later a
9119 ** row with the same primary key values inserted while a session object is
9120 ** active, the resulting changeset will contain an UPDATE change instead of
9121 ** a DELETE and an INSERT.
9123 ** When a session object is disabled (see the [sqlite3session_enable()] API),
9124 ** it does not accumulate records when rows are inserted, updated or deleted.
9125 ** This may appear to have some counter-intuitive effects if a single row
9126 ** is written to more than once during a session. For example, if a row
9127 ** is inserted while a session object is enabled, then later deleted while
9128 ** the same session object is disabled, no INSERT record will appear in the
9129 ** changeset, even though the delete took place while the session was disabled.
9130 ** Or, if one field of a row is updated while a session is disabled, and
9131 ** another field of the same row is updated while the session is enabled, the
9132 ** resulting changeset will contain an UPDATE change that updates both fields.
9134 SQLITE_API int sqlite3session_changeset(
9135 sqlite3_session *pSession, /* Session object */
9136 int *pnChangeset, /* OUT: Size of buffer at *ppChangeset */
9137 void **ppChangeset /* OUT: Buffer containing changeset */
9141 ** CAPI3REF: Load The Difference Between Tables Into A Session
9143 ** If it is not already attached to the session object passed as the first
9144 ** argument, this function attaches table zTbl in the same manner as the
9145 ** [sqlite3session_attach()] function. If zTbl does not exist, or if it
9146 ** does not have a primary key, this function is a no-op (but does not return
9149 ** Argument zFromDb must be the name of a database ("main", "temp" etc.)
9150 ** attached to the same database handle as the session object that contains
9151 ** a table compatible with the table attached to the session by this function.
9152 ** A table is considered compatible if it:
9155 ** <li> Has the same name,
9156 ** <li> Has the same set of columns declared in the same order, and
9157 ** <li> Has the same PRIMARY KEY definition.
9160 ** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
9161 ** are compatible but do not have any PRIMARY KEY columns, it is not an error
9162 ** but no changes are added to the session object. As with other session
9163 ** APIs, tables without PRIMARY KEYs are simply ignored.
9165 ** This function adds a set of changes to the session object that could be
9166 ** used to update the table in database zFrom (call this the "from-table")
9167 ** so that its content is the same as the table attached to the session
9168 ** object (call this the "to-table"). Specifically:
9171 ** <li> For each row (primary key) that exists in the to-table but not in
9172 ** the from-table, an INSERT record is added to the session object.
9174 ** <li> For each row (primary key) that exists in the to-table but not in
9175 ** the from-table, a DELETE record is added to the session object.
9177 ** <li> For each row (primary key) that exists in both tables, but features
9178 ** different non-PK values in each, an UPDATE record is added to the
9182 ** To clarify, if this function is called and then a changeset constructed
9183 ** using [sqlite3session_changeset()], then after applying that changeset to
9184 ** database zFrom the contents of the two compatible tables would be
9187 ** It an error if database zFrom does not exist or does not contain the
9188 ** required compatible table.
9190 ** If the operation successful, SQLITE_OK is returned. Otherwise, an SQLite
9191 ** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
9192 ** may be set to point to a buffer containing an English language error
9193 ** message. It is the responsibility of the caller to free this buffer using
9196 SQLITE_API int sqlite3session_diff(
9197 sqlite3_session *pSession,
9198 const char *zFromDb,
9205 ** CAPI3REF: Generate A Patchset From A Session Object
9207 ** The differences between a patchset and a changeset are that:
9210 ** <li> DELETE records consist of the primary key fields only. The
9211 ** original values of other fields are omitted.
9212 ** <li> The original values of any modified fields are omitted from
9216 ** A patchset blob may be used with up to date versions of all
9217 ** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(),
9218 ** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
9219 ** attempting to use a patchset blob with old versions of the
9220 ** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error.
9222 ** Because the non-primary key "old.*" fields are omitted, no
9223 ** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
9224 ** is passed to the sqlite3changeset_apply() API. Other conflict types work
9225 ** in the same way as for changesets.
9227 ** Changes within a patchset are ordered in the same way as for changesets
9228 ** generated by the sqlite3session_changeset() function (i.e. all changes for
9229 ** a single table are grouped together, tables appear in the order in which
9230 ** they were attached to the session object).
9232 SQLITE_API int sqlite3session_patchset(
9233 sqlite3_session *pSession, /* Session object */
9234 int *pnPatchset, /* OUT: Size of buffer at *ppPatchset */
9235 void **ppPatchset /* OUT: Buffer containing patchset */
9239 ** CAPI3REF: Test if a changeset has recorded any changes.
9241 ** Return non-zero if no changes to attached tables have been recorded by
9242 ** the session object passed as the first argument. Otherwise, if one or
9243 ** more changes have been recorded, return zero.
9245 ** Even if this function returns zero, it is possible that calling
9246 ** [sqlite3session_changeset()] on the session handle may still return a
9247 ** changeset that contains no changes. This can happen when a row in
9248 ** an attached table is modified and then later on the original values
9249 ** are restored. However, if this function returns non-zero, then it is
9250 ** guaranteed that a call to sqlite3session_changeset() will return a
9251 ** changeset containing zero changes.
9253 SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);
9256 ** CAPI3REF: Create An Iterator To Traverse A Changeset
9258 ** Create an iterator used to iterate through the contents of a changeset.
9259 ** If successful, *pp is set to point to the iterator handle and SQLITE_OK
9260 ** is returned. Otherwise, if an error occurs, *pp is set to zero and an
9261 ** SQLite error code is returned.
9263 ** The following functions can be used to advance and query a changeset
9264 ** iterator created by this function:
9267 ** <li> [sqlite3changeset_next()]
9268 ** <li> [sqlite3changeset_op()]
9269 ** <li> [sqlite3changeset_new()]
9270 ** <li> [sqlite3changeset_old()]
9273 ** It is the responsibility of the caller to eventually destroy the iterator
9274 ** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
9275 ** changeset (pChangeset) must remain valid until after the iterator is
9278 ** Assuming the changeset blob was created by one of the
9279 ** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
9280 ** [sqlite3changeset_invert()] functions, all changes within the changeset
9281 ** that apply to a single table are grouped together. This means that when
9282 ** an application iterates through a changeset using an iterator created by
9283 ** this function, all changes that relate to a single table are visited
9284 ** consecutively. There is no chance that the iterator will visit a change
9285 ** the applies to table X, then one for table Y, and then later on visit
9286 ** another change for table X.
9288 SQLITE_API int sqlite3changeset_start(
9289 sqlite3_changeset_iter **pp, /* OUT: New changeset iterator handle */
9290 int nChangeset, /* Size of changeset blob in bytes */
9291 void *pChangeset /* Pointer to blob containing changeset */
9296 ** CAPI3REF: Advance A Changeset Iterator
9298 ** This function may only be used with iterators created by function
9299 ** [sqlite3changeset_start()]. If it is called on an iterator passed to
9300 ** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
9301 ** is returned and the call has no effect.
9303 ** Immediately after an iterator is created by sqlite3changeset_start(), it
9304 ** does not point to any change in the changeset. Assuming the changeset
9305 ** is not empty, the first call to this function advances the iterator to
9306 ** point to the first change in the changeset. Each subsequent call advances
9307 ** the iterator to point to the next change in the changeset (if any). If
9308 ** no error occurs and the iterator points to a valid change after a call
9309 ** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned.
9310 ** Otherwise, if all changes in the changeset have already been visited,
9311 ** SQLITE_DONE is returned.
9313 ** If an error occurs, an SQLite error code is returned. Possible error
9314 ** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or
9317 SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *pIter);
9320 ** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
9322 ** The pIter argument passed to this function may either be an iterator
9323 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
9324 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
9325 ** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
9326 ** is not the case, this function returns [SQLITE_MISUSE].
9328 ** If argument pzTab is not NULL, then *pzTab is set to point to a
9329 ** nul-terminated utf-8 encoded string containing the name of the table
9330 ** affected by the current change. The buffer remains valid until either
9331 ** sqlite3changeset_next() is called on the iterator or until the
9332 ** conflict-handler function returns. If pnCol is not NULL, then *pnCol is
9333 ** set to the number of columns in the table affected by the change. If
9334 ** pbIncorrect is not NULL, then *pbIndirect is set to true (1) if the change
9335 ** is an indirect change, or false (0) otherwise. See the documentation for
9336 ** [sqlite3session_indirect()] for a description of direct and indirect
9337 ** changes. Finally, if pOp is not NULL, then *pOp is set to one of
9338 ** [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE], depending on the
9339 ** type of change that the iterator currently points to.
9341 ** If no error occurs, SQLITE_OK is returned. If an error does occur, an
9342 ** SQLite error code is returned. The values of the output variables may not
9343 ** be trusted in this case.
9345 SQLITE_API int sqlite3changeset_op(
9346 sqlite3_changeset_iter *pIter, /* Iterator object */
9347 const char **pzTab, /* OUT: Pointer to table name */
9348 int *pnCol, /* OUT: Number of columns in table */
9349 int *pOp, /* OUT: SQLITE_INSERT, DELETE or UPDATE */
9350 int *pbIndirect /* OUT: True for an 'indirect' change */
9354 ** CAPI3REF: Obtain The Primary Key Definition Of A Table
9356 ** For each modified table, a changeset includes the following:
9359 ** <li> The number of columns in the table, and
9360 ** <li> Which of those columns make up the tables PRIMARY KEY.
9363 ** This function is used to find which columns comprise the PRIMARY KEY of
9364 ** the table modified by the change that iterator pIter currently points to.
9365 ** If successful, *pabPK is set to point to an array of nCol entries, where
9366 ** nCol is the number of columns in the table. Elements of *pabPK are set to
9367 ** 0x01 if the corresponding column is part of the tables primary key, or
9368 ** 0x00 if it is not.
9370 ** If argument pnCol is not NULL, then *pnCol is set to the number of columns
9373 ** If this function is called when the iterator does not point to a valid
9374 ** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
9375 ** SQLITE_OK is returned and the output variables populated as described
9378 SQLITE_API int sqlite3changeset_pk(
9379 sqlite3_changeset_iter *pIter, /* Iterator object */
9380 unsigned char **pabPK, /* OUT: Array of boolean - true for PK cols */
9381 int *pnCol /* OUT: Number of entries in output array */
9385 ** CAPI3REF: Obtain old.* Values From A Changeset Iterator
9387 ** The pIter argument passed to this function may either be an iterator
9388 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
9389 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
9390 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
9391 ** Furthermore, it may only be called if the type of change that the iterator
9392 ** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
9393 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
9395 ** Argument iVal must be greater than or equal to 0, and less than the number
9396 ** of columns in the table affected by the current change. Otherwise,
9397 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
9399 ** If successful, this function sets *ppValue to point to a protected
9400 ** sqlite3_value object containing the iVal'th value from the vector of
9401 ** original row values stored as part of the UPDATE or DELETE change and
9402 ** returns SQLITE_OK. The name of the function comes from the fact that this
9403 ** is similar to the "old.*" columns available to update or delete triggers.
9405 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
9406 ** is returned and *ppValue is set to NULL.
9408 SQLITE_API int sqlite3changeset_old(
9409 sqlite3_changeset_iter *pIter, /* Changeset iterator */
9410 int iVal, /* Column number */
9411 sqlite3_value **ppValue /* OUT: Old value (or NULL pointer) */
9415 ** CAPI3REF: Obtain new.* Values From A Changeset Iterator
9417 ** The pIter argument passed to this function may either be an iterator
9418 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
9419 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
9420 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
9421 ** Furthermore, it may only be called if the type of change that the iterator
9422 ** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
9423 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
9425 ** Argument iVal must be greater than or equal to 0, and less than the number
9426 ** of columns in the table affected by the current change. Otherwise,
9427 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
9429 ** If successful, this function sets *ppValue to point to a protected
9430 ** sqlite3_value object containing the iVal'th value from the vector of
9431 ** new row values stored as part of the UPDATE or INSERT change and
9432 ** returns SQLITE_OK. If the change is an UPDATE and does not include
9433 ** a new value for the requested column, *ppValue is set to NULL and
9434 ** SQLITE_OK returned. The name of the function comes from the fact that
9435 ** this is similar to the "new.*" columns available to update or delete
9438 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
9439 ** is returned and *ppValue is set to NULL.
9441 SQLITE_API int sqlite3changeset_new(
9442 sqlite3_changeset_iter *pIter, /* Changeset iterator */
9443 int iVal, /* Column number */
9444 sqlite3_value **ppValue /* OUT: New value (or NULL pointer) */
9448 ** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
9450 ** This function should only be used with iterator objects passed to a
9451 ** conflict-handler callback by [sqlite3changeset_apply()] with either
9452 ** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
9453 ** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
9456 ** Argument iVal must be greater than or equal to 0, and less than the number
9457 ** of columns in the table affected by the current change. Otherwise,
9458 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
9460 ** If successful, this function sets *ppValue to point to a protected
9461 ** sqlite3_value object containing the iVal'th value from the
9462 ** "conflicting row" associated with the current conflict-handler callback
9463 ** and returns SQLITE_OK.
9465 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
9466 ** is returned and *ppValue is set to NULL.
9468 SQLITE_API int sqlite3changeset_conflict(
9469 sqlite3_changeset_iter *pIter, /* Changeset iterator */
9470 int iVal, /* Column number */
9471 sqlite3_value **ppValue /* OUT: Value from conflicting row */
9475 ** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
9477 ** This function may only be called with an iterator passed to an
9478 ** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
9479 ** it sets the output variable to the total number of known foreign key
9480 ** violations in the destination database and returns SQLITE_OK.
9482 ** In all other cases this function returns SQLITE_MISUSE.
9484 SQLITE_API int sqlite3changeset_fk_conflicts(
9485 sqlite3_changeset_iter *pIter, /* Changeset iterator */
9486 int *pnOut /* OUT: Number of FK violations */
9491 ** CAPI3REF: Finalize A Changeset Iterator
9493 ** This function is used to finalize an iterator allocated with
9494 ** [sqlite3changeset_start()].
9496 ** This function should only be called on iterators created using the
9497 ** [sqlite3changeset_start()] function. If an application calls this
9498 ** function with an iterator passed to a conflict-handler by
9499 ** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
9500 ** call has no effect.
9502 ** If an error was encountered within a call to an sqlite3changeset_xxx()
9503 ** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an
9504 ** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
9505 ** to that error is returned by this function. Otherwise, SQLITE_OK is
9506 ** returned. This is to allow the following pattern (pseudo-code):
9508 ** sqlite3changeset_start();
9509 ** while( SQLITE_ROW==sqlite3changeset_next() ){
9510 ** // Do something with change.
9512 ** rc = sqlite3changeset_finalize();
9513 ** if( rc!=SQLITE_OK ){
9514 ** // An error has occurred
9517 SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);
9520 ** CAPI3REF: Invert A Changeset
9522 ** This function is used to "invert" a changeset object. Applying an inverted
9523 ** changeset to a database reverses the effects of applying the uninverted
9524 ** changeset. Specifically:
9527 ** <li> Each DELETE change is changed to an INSERT, and
9528 ** <li> Each INSERT change is changed to a DELETE, and
9529 ** <li> For each UPDATE change, the old.* and new.* values are exchanged.
9532 ** This function does not change the order in which changes appear within
9533 ** the changeset. It merely reverses the sense of each individual change.
9535 ** If successful, a pointer to a buffer containing the inverted changeset
9536 ** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
9537 ** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
9538 ** zeroed and an SQLite error code returned.
9540 ** It is the responsibility of the caller to eventually call sqlite3_free()
9541 ** on the *ppOut pointer to free the buffer allocation following a successful
9542 ** call to this function.
9544 ** WARNING/TODO: This function currently assumes that the input is a valid
9545 ** changeset. If it is not, the results are undefined.
9547 SQLITE_API int sqlite3changeset_invert(
9548 int nIn, const void *pIn, /* Input changeset */
9549 int *pnOut, void **ppOut /* OUT: Inverse of input */
9553 ** CAPI3REF: Concatenate Two Changeset Objects
9555 ** This function is used to concatenate two changesets, A and B, into a
9556 ** single changeset. The result is a changeset equivalent to applying
9557 ** changeset A followed by changeset B.
9559 ** This function combines the two input changesets using an
9560 ** sqlite3_changegroup object. Calling it produces similar results as the
9561 ** following code fragment:
9563 ** sqlite3_changegroup *pGrp;
9564 ** rc = sqlite3_changegroup_new(&pGrp);
9565 ** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
9566 ** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
9567 ** if( rc==SQLITE_OK ){
9568 ** rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
9574 ** Refer to the sqlite3_changegroup documentation below for details.
9576 SQLITE_API int sqlite3changeset_concat(
9577 int nA, /* Number of bytes in buffer pA */
9578 void *pA, /* Pointer to buffer containing changeset A */
9579 int nB, /* Number of bytes in buffer pB */
9580 void *pB, /* Pointer to buffer containing changeset B */
9581 int *pnOut, /* OUT: Number of bytes in output changeset */
9582 void **ppOut /* OUT: Buffer containing output changeset */
9587 ** CAPI3REF: Changegroup Handle
9589 typedef struct sqlite3_changegroup sqlite3_changegroup;
9592 ** CAPI3REF: Create A New Changegroup Object
9594 ** An sqlite3_changegroup object is used to combine two or more changesets
9595 ** (or patchsets) into a single changeset (or patchset). A single changegroup
9596 ** object may combine changesets or patchsets, but not both. The output is
9597 ** always in the same format as the input.
9599 ** If successful, this function returns SQLITE_OK and populates (*pp) with
9600 ** a pointer to a new sqlite3_changegroup object before returning. The caller
9601 ** should eventually free the returned object using a call to
9602 ** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
9603 ** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
9605 ** The usual usage pattern for an sqlite3_changegroup object is as follows:
9608 ** <li> It is created using a call to sqlite3changegroup_new().
9610 ** <li> Zero or more changesets (or patchsets) are added to the object
9611 ** by calling sqlite3changegroup_add().
9613 ** <li> The result of combining all input changesets together is obtained
9614 ** by the application via a call to sqlite3changegroup_output().
9616 ** <li> The object is deleted using a call to sqlite3changegroup_delete().
9619 ** Any number of calls to add() and output() may be made between the calls to
9620 ** new() and delete(), and in any order.
9622 ** As well as the regular sqlite3changegroup_add() and
9623 ** sqlite3changegroup_output() functions, also available are the streaming
9624 ** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
9626 SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp);
9629 ** CAPI3REF: Add A Changeset To A Changegroup
9631 ** Add all changes within the changeset (or patchset) in buffer pData (size
9632 ** nData bytes) to the changegroup.
9634 ** If the buffer contains a patchset, then all prior calls to this function
9635 ** on the same changegroup object must also have specified patchsets. Or, if
9636 ** the buffer contains a changeset, so must have the earlier calls to this
9637 ** function. Otherwise, SQLITE_ERROR is returned and no changes are added
9638 ** to the changegroup.
9640 ** Rows within the changeset and changegroup are identified by the values in
9641 ** their PRIMARY KEY columns. A change in the changeset is considered to
9642 ** apply to the same row as a change already present in the changegroup if
9643 ** the two rows have the same primary key.
9645 ** Changes to rows that do not already appear in the changegroup are
9646 ** simply copied into it. Or, if both the new changeset and the changegroup
9647 ** contain changes that apply to a single row, the final contents of the
9648 ** changegroup depends on the type of each change, as follows:
9650 ** <table border=1 style="margin-left:8ex;margin-right:8ex">
9651 ** <tr><th style="white-space:pre">Existing Change </th>
9652 ** <th style="white-space:pre">New Change </th>
9653 ** <th>Output Change
9654 ** <tr><td>INSERT <td>INSERT <td>
9655 ** The new change is ignored. This case does not occur if the new
9656 ** changeset was recorded immediately after the changesets already
9657 ** added to the changegroup.
9658 ** <tr><td>INSERT <td>UPDATE <td>
9659 ** The INSERT change remains in the changegroup. The values in the
9660 ** INSERT change are modified as if the row was inserted by the
9661 ** existing change and then updated according to the new change.
9662 ** <tr><td>INSERT <td>DELETE <td>
9663 ** The existing INSERT is removed from the changegroup. The DELETE is
9665 ** <tr><td>UPDATE <td>INSERT <td>
9666 ** The new change is ignored. This case does not occur if the new
9667 ** changeset was recorded immediately after the changesets already
9668 ** added to the changegroup.
9669 ** <tr><td>UPDATE <td>UPDATE <td>
9670 ** The existing UPDATE remains within the changegroup. It is amended
9671 ** so that the accompanying values are as if the row was updated once
9672 ** by the existing change and then again by the new change.
9673 ** <tr><td>UPDATE <td>DELETE <td>
9674 ** The existing UPDATE is replaced by the new DELETE within the
9676 ** <tr><td>DELETE <td>INSERT <td>
9677 ** If one or more of the column values in the row inserted by the
9678 ** new change differ from those in the row deleted by the existing
9679 ** change, the existing DELETE is replaced by an UPDATE within the
9680 ** changegroup. Otherwise, if the inserted row is exactly the same
9681 ** as the deleted row, the existing DELETE is simply discarded.
9682 ** <tr><td>DELETE <td>UPDATE <td>
9683 ** The new change is ignored. This case does not occur if the new
9684 ** changeset was recorded immediately after the changesets already
9685 ** added to the changegroup.
9686 ** <tr><td>DELETE <td>DELETE <td>
9687 ** The new change is ignored. This case does not occur if the new
9688 ** changeset was recorded immediately after the changesets already
9689 ** added to the changegroup.
9692 ** If the new changeset contains changes to a table that is already present
9693 ** in the changegroup, then the number of columns and the position of the
9694 ** primary key columns for the table must be consistent. If this is not the
9695 ** case, this function fails with SQLITE_SCHEMA. If the input changeset
9696 ** appears to be corrupt and the corruption is detected, SQLITE_CORRUPT is
9697 ** returned. Or, if an out-of-memory condition occurs during processing, this
9698 ** function returns SQLITE_NOMEM. In all cases, if an error occurs the
9699 ** final contents of the changegroup is undefined.
9701 ** If no error occurs, SQLITE_OK is returned.
9703 SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData);
9706 ** CAPI3REF: Obtain A Composite Changeset From A Changegroup
9708 ** Obtain a buffer containing a changeset (or patchset) representing the
9709 ** current contents of the changegroup. If the inputs to the changegroup
9710 ** were themselves changesets, the output is a changeset. Or, if the
9711 ** inputs were patchsets, the output is also a patchset.
9713 ** As with the output of the sqlite3session_changeset() and
9714 ** sqlite3session_patchset() functions, all changes related to a single
9715 ** table are grouped together in the output of this function. Tables appear
9716 ** in the same order as for the very first changeset added to the changegroup.
9717 ** If the second or subsequent changesets added to the changegroup contain
9718 ** changes for tables that do not appear in the first changeset, they are
9719 ** appended onto the end of the output changeset, again in the order in
9720 ** which they are first encountered.
9722 ** If an error occurs, an SQLite error code is returned and the output
9723 ** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
9724 ** is returned and the output variables are set to the size of and a
9725 ** pointer to the output buffer, respectively. In this case it is the
9726 ** responsibility of the caller to eventually free the buffer using a
9727 ** call to sqlite3_free().
9729 SQLITE_API int sqlite3changegroup_output(
9730 sqlite3_changegroup*,
9731 int *pnData, /* OUT: Size of output buffer in bytes */
9732 void **ppData /* OUT: Pointer to output buffer */
9736 ** CAPI3REF: Delete A Changegroup Object
9738 SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup*);
9741 ** CAPI3REF: Apply A Changeset To A Database
9743 ** Apply a changeset to a database. This function attempts to update the
9744 ** "main" database attached to handle db with the changes found in the
9745 ** changeset passed via the second and third arguments.
9747 ** The fourth argument (xFilter) passed to this function is the "filter
9748 ** callback". If it is not NULL, then for each table affected by at least one
9749 ** change in the changeset, the filter callback is invoked with
9750 ** the table name as the second argument, and a copy of the context pointer
9751 ** passed as the sixth argument to this function as the first. If the "filter
9752 ** callback" returns zero, then no attempt is made to apply any changes to
9753 ** the table. Otherwise, if the return value is non-zero or the xFilter
9754 ** argument to this function is NULL, all changes related to the table are
9757 ** For each table that is not excluded by the filter callback, this function
9758 ** tests that the target database contains a compatible table. A table is
9759 ** considered compatible if all of the following are true:
9762 ** <li> The table has the same name as the name recorded in the
9764 ** <li> The table has at least as many columns as recorded in the
9766 ** <li> The table has primary key columns in the same position as
9767 ** recorded in the changeset.
9770 ** If there is no compatible table, it is not an error, but none of the
9771 ** changes associated with the table are applied. A warning message is issued
9772 ** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
9773 ** one such warning is issued for each table in the changeset.
9775 ** For each change for which there is a compatible table, an attempt is made
9776 ** to modify the table contents according to the UPDATE, INSERT or DELETE
9777 ** change. If a change cannot be applied cleanly, the conflict handler
9778 ** function passed as the fifth argument to sqlite3changeset_apply() may be
9779 ** invoked. A description of exactly when the conflict handler is invoked for
9780 ** each type of change is below.
9782 ** Unlike the xFilter argument, xConflict may not be passed NULL. The results
9783 ** of passing anything other than a valid function pointer as the xConflict
9784 ** argument are undefined.
9786 ** Each time the conflict handler function is invoked, it must return one
9787 ** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or
9788 ** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
9789 ** if the second argument passed to the conflict handler is either
9790 ** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
9791 ** returns an illegal value, any changes already made are rolled back and
9792 ** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different
9793 ** actions are taken by sqlite3changeset_apply() depending on the value
9794 ** returned by each invocation of the conflict-handler function. Refer to
9795 ** the documentation for the three
9796 ** [SQLITE_CHANGESET_OMIT|available return values] for details.
9799 ** <dt>DELETE Changes<dd>
9800 ** For each DELETE change, this function checks if the target database
9801 ** contains a row with the same primary key value (or values) as the
9802 ** original row values stored in the changeset. If it does, and the values
9803 ** stored in all non-primary key columns also match the values stored in
9804 ** the changeset the row is deleted from the target database.
9806 ** If a row with matching primary key values is found, but one or more of
9807 ** the non-primary key fields contains a value different from the original
9808 ** row value stored in the changeset, the conflict-handler function is
9809 ** invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the
9810 ** database table has more columns than are recorded in the changeset,
9811 ** only the values of those non-primary key fields are compared against
9812 ** the current database contents - any trailing database table columns
9815 ** If no row with matching primary key values is found in the database,
9816 ** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
9817 ** passed as the second argument.
9819 ** If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
9820 ** (which can only happen if a foreign key constraint is violated), the
9821 ** conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
9822 ** passed as the second argument. This includes the case where the DELETE
9823 ** operation is attempted because an earlier call to the conflict handler
9824 ** function returned [SQLITE_CHANGESET_REPLACE].
9826 ** <dt>INSERT Changes<dd>
9827 ** For each INSERT change, an attempt is made to insert the new row into
9828 ** the database. If the changeset row contains fewer fields than the
9829 ** database table, the trailing fields are populated with their default
9832 ** If the attempt to insert the row fails because the database already
9833 ** contains a row with the same primary key values, the conflict handler
9834 ** function is invoked with the second argument set to
9835 ** [SQLITE_CHANGESET_CONFLICT].
9837 ** If the attempt to insert the row fails because of some other constraint
9838 ** violation (e.g. NOT NULL or UNIQUE), the conflict handler function is
9839 ** invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
9840 ** This includes the case where the INSERT operation is re-attempted because
9841 ** an earlier call to the conflict handler function returned
9842 ** [SQLITE_CHANGESET_REPLACE].
9844 ** <dt>UPDATE Changes<dd>
9845 ** For each UPDATE change, this function checks if the target database
9846 ** contains a row with the same primary key value (or values) as the
9847 ** original row values stored in the changeset. If it does, and the values
9848 ** stored in all modified non-primary key columns also match the values
9849 ** stored in the changeset the row is updated within the target database.
9851 ** If a row with matching primary key values is found, but one or more of
9852 ** the modified non-primary key fields contains a value different from an
9853 ** original row value stored in the changeset, the conflict-handler function
9854 ** is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
9855 ** UPDATE changes only contain values for non-primary key fields that are
9856 ** to be modified, only those fields need to match the original values to
9857 ** avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
9859 ** If no row with matching primary key values is found in the database,
9860 ** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
9861 ** passed as the second argument.
9863 ** If the UPDATE operation is attempted, but SQLite returns
9864 ** SQLITE_CONSTRAINT, the conflict-handler function is invoked with
9865 ** [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
9866 ** This includes the case where the UPDATE operation is attempted after
9867 ** an earlier call to the conflict handler function returned
9868 ** [SQLITE_CHANGESET_REPLACE].
9871 ** It is safe to execute SQL statements, including those that write to the
9872 ** table that the callback related to, from within the xConflict callback.
9873 ** This can be used to further customize the applications conflict
9874 ** resolution strategy.
9876 ** All changes made by this function are enclosed in a savepoint transaction.
9877 ** If any other error (aside from a constraint failure when attempting to
9878 ** write to the target database) occurs, then the savepoint transaction is
9879 ** rolled back, restoring the target database to its original state, and an
9880 ** SQLite error code returned.
9882 SQLITE_API int sqlite3changeset_apply(
9883 sqlite3 *db, /* Apply change to "main" db of this handle */
9884 int nChangeset, /* Size of changeset in bytes */
9885 void *pChangeset, /* Changeset blob */
9887 void *pCtx, /* Copy of sixth arg to _apply() */
9888 const char *zTab /* Table name */
9891 void *pCtx, /* Copy of sixth arg to _apply() */
9892 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */
9893 sqlite3_changeset_iter *p /* Handle describing change and conflict */
9895 void *pCtx /* First argument passed to xConflict */
9899 ** CAPI3REF: Constants Passed To The Conflict Handler
9901 ** Values that may be passed as the second argument to a conflict-handler.
9904 ** <dt>SQLITE_CHANGESET_DATA<dd>
9905 ** The conflict handler is invoked with CHANGESET_DATA as the second argument
9906 ** when processing a DELETE or UPDATE change if a row with the required
9907 ** PRIMARY KEY fields is present in the database, but one or more other
9908 ** (non primary-key) fields modified by the update do not contain the
9909 ** expected "before" values.
9911 ** The conflicting row, in this case, is the database row with the matching
9914 ** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
9915 ** The conflict handler is invoked with CHANGESET_NOTFOUND as the second
9916 ** argument when processing a DELETE or UPDATE change if a row with the
9917 ** required PRIMARY KEY fields is not present in the database.
9919 ** There is no conflicting row in this case. The results of invoking the
9920 ** sqlite3changeset_conflict() API are undefined.
9922 ** <dt>SQLITE_CHANGESET_CONFLICT<dd>
9923 ** CHANGESET_CONFLICT is passed as the second argument to the conflict
9924 ** handler while processing an INSERT change if the operation would result
9925 ** in duplicate primary key values.
9927 ** The conflicting row in this case is the database row with the matching
9930 ** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
9931 ** If foreign key handling is enabled, and applying a changeset leaves the
9932 ** database in a state containing foreign key violations, the conflict
9933 ** handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
9934 ** exactly once before the changeset is committed. If the conflict handler
9935 ** returns CHANGESET_OMIT, the changes, including those that caused the
9936 ** foreign key constraint violation, are committed. Or, if it returns
9937 ** CHANGESET_ABORT, the changeset is rolled back.
9939 ** No current or conflicting row information is provided. The only function
9940 ** it is possible to call on the supplied sqlite3_changeset_iter handle
9941 ** is sqlite3changeset_fk_conflicts().
9943 ** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
9944 ** If any other constraint violation occurs while applying a change (i.e.
9945 ** a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is
9946 ** invoked with CHANGESET_CONSTRAINT as the second argument.
9948 ** There is no conflicting row in this case. The results of invoking the
9949 ** sqlite3changeset_conflict() API are undefined.
9953 #define SQLITE_CHANGESET_DATA 1
9954 #define SQLITE_CHANGESET_NOTFOUND 2
9955 #define SQLITE_CHANGESET_CONFLICT 3
9956 #define SQLITE_CHANGESET_CONSTRAINT 4
9957 #define SQLITE_CHANGESET_FOREIGN_KEY 5
9960 ** CAPI3REF: Constants Returned By The Conflict Handler
9962 ** A conflict handler callback must return one of the following three values.
9965 ** <dt>SQLITE_CHANGESET_OMIT<dd>
9966 ** If a conflict handler returns this value no special action is taken. The
9967 ** change that caused the conflict is not applied. The session module
9968 ** continues to the next change in the changeset.
9970 ** <dt>SQLITE_CHANGESET_REPLACE<dd>
9971 ** This value may only be returned if the second argument to the conflict
9972 ** handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
9973 ** is not the case, any changes applied so far are rolled back and the
9974 ** call to sqlite3changeset_apply() returns SQLITE_MISUSE.
9976 ** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
9977 ** handler, then the conflicting row is either updated or deleted, depending
9978 ** on the type of change.
9980 ** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
9981 ** handler, then the conflicting row is removed from the database and a
9982 ** second attempt to apply the change is made. If this second attempt fails,
9983 ** the original row is restored to the database before continuing.
9985 ** <dt>SQLITE_CHANGESET_ABORT<dd>
9986 ** If this value is returned, any changes applied so far are rolled back
9987 ** and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
9990 #define SQLITE_CHANGESET_OMIT 0
9991 #define SQLITE_CHANGESET_REPLACE 1
9992 #define SQLITE_CHANGESET_ABORT 2
9995 ** CAPI3REF: Streaming Versions of API functions.
9997 ** The six streaming API xxx_strm() functions serve similar purposes to the
9998 ** corresponding non-streaming API functions:
10000 ** <table border=1 style="margin-left:8ex;margin-right:8ex">
10001 ** <tr><th>Streaming function<th>Non-streaming equivalent</th>
10002 ** <tr><td>sqlite3changeset_apply_strm<td>[sqlite3changeset_apply]
10003 ** <tr><td>sqlite3changeset_concat_strm<td>[sqlite3changeset_concat]
10004 ** <tr><td>sqlite3changeset_invert_strm<td>[sqlite3changeset_invert]
10005 ** <tr><td>sqlite3changeset_start_strm<td>[sqlite3changeset_start]
10006 ** <tr><td>sqlite3session_changeset_strm<td>[sqlite3session_changeset]
10007 ** <tr><td>sqlite3session_patchset_strm<td>[sqlite3session_patchset]
10010 ** Non-streaming functions that accept changesets (or patchsets) as input
10011 ** require that the entire changeset be stored in a single buffer in memory.
10012 ** Similarly, those that return a changeset or patchset do so by returning
10013 ** a pointer to a single large buffer allocated using sqlite3_malloc().
10014 ** Normally this is convenient. However, if an application running in a
10015 ** low-memory environment is required to handle very large changesets, the
10016 ** large contiguous memory allocations required can become onerous.
10018 ** In order to avoid this problem, instead of a single large buffer, input
10019 ** is passed to a streaming API functions by way of a callback function that
10020 ** the sessions module invokes to incrementally request input data as it is
10021 ** required. In all cases, a pair of API function parameters such as
10024 ** int nChangeset,
10025 ** void *pChangeset,
10031 ** int (*xInput)(void *pIn, void *pData, int *pnData),
10032 ** void *pIn,
10035 ** Each time the xInput callback is invoked by the sessions module, the first
10036 ** argument passed is a copy of the supplied pIn context pointer. The second
10037 ** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no
10038 ** error occurs the xInput method should copy up to (*pnData) bytes of data
10039 ** into the buffer and set (*pnData) to the actual number of bytes copied
10040 ** before returning SQLITE_OK. If the input is completely exhausted, (*pnData)
10041 ** should be set to zero to indicate this. Or, if an error occurs, an SQLite
10042 ** error code should be returned. In all cases, if an xInput callback returns
10043 ** an error, all processing is abandoned and the streaming API function
10044 ** returns a copy of the error code to the caller.
10046 ** In the case of sqlite3changeset_start_strm(), the xInput callback may be
10047 ** invoked by the sessions module at any point during the lifetime of the
10048 ** iterator. If such an xInput callback returns an error, the iterator enters
10049 ** an error state, whereby all subsequent calls to iterator functions
10050 ** immediately fail with the same error code as returned by xInput.
10052 ** Similarly, streaming API functions that return changesets (or patchsets)
10053 ** return them in chunks by way of a callback function instead of via a
10054 ** pointer to a single large buffer. In this case, a pair of parameters such
10058 ** int *pnChangeset,
10059 ** void **ppChangeset,
10065 ** int (*xOutput)(void *pOut, const void *pData, int nData),
10066 ** void *pOut
10069 ** The xOutput callback is invoked zero or more times to return data to
10070 ** the application. The first parameter passed to each call is a copy of the
10071 ** pOut pointer supplied by the application. The second parameter, pData,
10072 ** points to a buffer nData bytes in size containing the chunk of output
10073 ** data being returned. If the xOutput callback successfully processes the
10074 ** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
10075 ** it should return some other SQLite error code. In this case processing
10076 ** is immediately abandoned and the streaming API function returns a copy
10077 ** of the xOutput error code to the application.
10079 ** The sessions module never invokes an xOutput callback with the third
10080 ** parameter set to a value less than or equal to zero. Other than this,
10081 ** no guarantees are made as to the size of the chunks of data returned.
10083 SQLITE_API int sqlite3changeset_apply_strm(
10084 sqlite3 *db, /* Apply change to "main" db of this handle */
10085 int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
10086 void *pIn, /* First arg for xInput */
10088 void *pCtx, /* Copy of sixth arg to _apply() */
10089 const char *zTab /* Table name */
10092 void *pCtx, /* Copy of sixth arg to _apply() */
10093 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */
10094 sqlite3_changeset_iter *p /* Handle describing change and conflict */
10096 void *pCtx /* First argument passed to xConflict */
10098 SQLITE_API int sqlite3changeset_concat_strm(
10099 int (*xInputA)(void *pIn, void *pData, int *pnData),
10101 int (*xInputB)(void *pIn, void *pData, int *pnData),
10103 int (*xOutput)(void *pOut, const void *pData, int nData),
10106 SQLITE_API int sqlite3changeset_invert_strm(
10107 int (*xInput)(void *pIn, void *pData, int *pnData),
10109 int (*xOutput)(void *pOut, const void *pData, int nData),
10112 SQLITE_API int sqlite3changeset_start_strm(
10113 sqlite3_changeset_iter **pp,
10114 int (*xInput)(void *pIn, void *pData, int *pnData),
10117 SQLITE_API int sqlite3session_changeset_strm(
10118 sqlite3_session *pSession,
10119 int (*xOutput)(void *pOut, const void *pData, int nData),
10122 SQLITE_API int sqlite3session_patchset_strm(
10123 sqlite3_session *pSession,
10124 int (*xOutput)(void *pOut, const void *pData, int nData),
10127 SQLITE_API int sqlite3changegroup_add_strm(sqlite3_changegroup*,
10128 int (*xInput)(void *pIn, void *pData, int *pnData),
10131 SQLITE_API int sqlite3changegroup_output_strm(sqlite3_changegroup*,
10132 int (*xOutput)(void *pOut, const void *pData, int nData),
10138 ** Make sure we can call this stuff from C++.
10144 #endif /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
10146 /******** End of sqlite3session.h *********/
10147 /******** Begin file fts5.h *********/
10151 ** The author disclaims copyright to this source code. In place of
10152 ** a legal notice, here is a blessing:
10154 ** May you do good and not evil.
10155 ** May you find forgiveness for yourself and forgive others.
10156 ** May you share freely, never taking more than you give.
10158 ******************************************************************************
10160 ** Interfaces to extend FTS5. Using the interfaces defined in this file,
10161 ** FTS5 may be extended with:
10163 ** * custom tokenizers, and
10164 ** * custom auxiliary functions.
10176 /*************************************************************************
10177 ** CUSTOM AUXILIARY FUNCTIONS
10179 ** Virtual table implementations may overload SQL functions by implementing
10180 ** the sqlite3_module.xFindFunction() method.
10183 typedef struct Fts5ExtensionApi Fts5ExtensionApi;
10184 typedef struct Fts5Context Fts5Context;
10185 typedef struct Fts5PhraseIter Fts5PhraseIter;
10187 typedef void (*fts5_extension_function)(
10188 const Fts5ExtensionApi *pApi, /* API offered by current FTS version */
10189 Fts5Context *pFts, /* First arg to pass to pApi functions */
10190 sqlite3_context *pCtx, /* Context for returning result/error */
10191 int nVal, /* Number of values in apVal[] array */
10192 sqlite3_value **apVal /* Array of trailing arguments */
10195 struct Fts5PhraseIter {
10196 const unsigned char *a;
10197 const unsigned char *b;
10201 ** EXTENSION API FUNCTIONS
10203 ** xUserData(pFts):
10204 ** Return a copy of the context pointer the extension function was
10205 ** registered with.
10207 ** xColumnTotalSize(pFts, iCol, pnToken):
10208 ** If parameter iCol is less than zero, set output variable *pnToken
10209 ** to the total number of tokens in the FTS5 table. Or, if iCol is
10210 ** non-negative but less than the number of columns in the table, return
10211 ** the total number of tokens in column iCol, considering all rows in
10214 ** If parameter iCol is greater than or equal to the number of columns
10215 ** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
10216 ** an OOM condition or IO error), an appropriate SQLite error code is
10219 ** xColumnCount(pFts):
10220 ** Return the number of columns in the table.
10222 ** xColumnSize(pFts, iCol, pnToken):
10223 ** If parameter iCol is less than zero, set output variable *pnToken
10224 ** to the total number of tokens in the current row. Or, if iCol is
10225 ** non-negative but less than the number of columns in the table, set
10226 ** *pnToken to the number of tokens in column iCol of the current row.
10228 ** If parameter iCol is greater than or equal to the number of columns
10229 ** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
10230 ** an OOM condition or IO error), an appropriate SQLite error code is
10233 ** This function may be quite inefficient if used with an FTS5 table
10234 ** created with the "columnsize=0" option.
10237 ** This function attempts to retrieve the text of column iCol of the
10238 ** current document. If successful, (*pz) is set to point to a buffer
10239 ** containing the text in utf-8 encoding, (*pn) is set to the size in bytes
10240 ** (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
10241 ** if an error occurs, an SQLite error code is returned and the final values
10242 ** of (*pz) and (*pn) are undefined.
10245 ** Returns the number of phrases in the current query expression.
10248 ** Returns the number of tokens in phrase iPhrase of the query. Phrases
10249 ** are numbered starting from zero.
10252 ** Set *pnInst to the total number of occurrences of all phrases within
10253 ** the query within the current row. Return SQLITE_OK if successful, or
10254 ** an error code (i.e. SQLITE_NOMEM) if an error occurs.
10256 ** This API can be quite slow if used with an FTS5 table created with the
10257 ** "detail=none" or "detail=column" option. If the FTS5 table is created
10258 ** with either "detail=none" or "detail=column" and "content=" option
10259 ** (i.e. if it is a contentless table), then this API always returns 0.
10262 ** Query for the details of phrase match iIdx within the current row.
10263 ** Phrase matches are numbered starting from zero, so the iIdx argument
10264 ** should be greater than or equal to zero and smaller than the value
10265 ** output by xInstCount().
10267 ** Usually, output parameter *piPhrase is set to the phrase number, *piCol
10268 ** to the column in which it occurs and *piOff the token offset of the
10269 ** first token of the phrase. The exception is if the table was created
10270 ** with the offsets=0 option specified. In this case *piOff is always
10273 ** Returns SQLITE_OK if successful, or an error code (i.e. SQLITE_NOMEM)
10274 ** if an error occurs.
10276 ** This API can be quite slow if used with an FTS5 table created with the
10277 ** "detail=none" or "detail=column" option.
10280 ** Returns the rowid of the current row.
10283 ** Tokenize text using the tokenizer belonging to the FTS5 table.
10285 ** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
10286 ** This API function is used to query the FTS table for phrase iPhrase
10287 ** of the current query. Specifically, a query equivalent to:
10289 ** ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
10291 ** with $p set to a phrase equivalent to the phrase iPhrase of the
10292 ** current query is executed. Any column filter that applies to
10293 ** phrase iPhrase of the current query is included in $p. For each
10294 ** row visited, the callback function passed as the fourth argument
10295 ** is invoked. The context and API objects passed to the callback
10296 ** function may be used to access the properties of each matched row.
10297 ** Invoking Api.xUserData() returns a copy of the pointer passed as
10298 ** the third argument to pUserData.
10300 ** If the callback function returns any value other than SQLITE_OK, the
10301 ** query is abandoned and the xQueryPhrase function returns immediately.
10302 ** If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
10303 ** Otherwise, the error code is propagated upwards.
10305 ** If the query runs to completion without incident, SQLITE_OK is returned.
10306 ** Or, if some error occurs before the query completes or is aborted by
10307 ** the callback, an SQLite error code is returned.
10310 ** xSetAuxdata(pFts5, pAux, xDelete)
10312 ** Save the pointer passed as the second argument as the extension functions
10313 ** "auxiliary data". The pointer may then be retrieved by the current or any
10314 ** future invocation of the same fts5 extension function made as part of
10315 ** of the same MATCH query using the xGetAuxdata() API.
10317 ** Each extension function is allocated a single auxiliary data slot for
10318 ** each FTS query (MATCH expression). If the extension function is invoked
10319 ** more than once for a single FTS query, then all invocations share a
10320 ** single auxiliary data context.
10322 ** If there is already an auxiliary data pointer when this function is
10323 ** invoked, then it is replaced by the new pointer. If an xDelete callback
10324 ** was specified along with the original pointer, it is invoked at this
10327 ** The xDelete callback, if one is specified, is also invoked on the
10328 ** auxiliary data pointer after the FTS5 query has finished.
10330 ** If an error (e.g. an OOM condition) occurs within this function, an
10331 ** the auxiliary data is set to NULL and an error code returned. If the
10332 ** xDelete parameter was not NULL, it is invoked on the auxiliary data
10333 ** pointer before returning.
10336 ** xGetAuxdata(pFts5, bClear)
10338 ** Returns the current auxiliary data pointer for the fts5 extension
10339 ** function. See the xSetAuxdata() method for details.
10341 ** If the bClear argument is non-zero, then the auxiliary data is cleared
10342 ** (set to NULL) before this function returns. In this case the xDelete,
10343 ** if any, is not invoked.
10346 ** xRowCount(pFts5, pnRow)
10348 ** This function is used to retrieve the total number of rows in the table.
10349 ** In other words, the same value that would be returned by:
10351 ** SELECT count(*) FROM ftstable;
10354 ** This function is used, along with type Fts5PhraseIter and the xPhraseNext
10355 ** method, to iterate through all instances of a single query phrase within
10356 ** the current row. This is the same information as is accessible via the
10357 ** xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
10358 ** to use, this API may be faster under some circumstances. To iterate
10359 ** through instances of phrase iPhrase, use the following code:
10361 ** Fts5PhraseIter iter;
10363 ** for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
10365 ** pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
10367 ** // An instance of phrase iPhrase at offset iOff of column iCol
10370 ** The Fts5PhraseIter structure is defined above. Applications should not
10371 ** modify this structure directly - it should only be used as shown above
10372 ** with the xPhraseFirst() and xPhraseNext() API methods (and by
10373 ** xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
10375 ** This API can be quite slow if used with an FTS5 table created with the
10376 ** "detail=none" or "detail=column" option. If the FTS5 table is created
10377 ** with either "detail=none" or "detail=column" and "content=" option
10378 ** (i.e. if it is a contentless table), then this API always iterates
10379 ** through an empty set (all calls to xPhraseFirst() set iCol to -1).
10382 ** See xPhraseFirst above.
10384 ** xPhraseFirstColumn()
10385 ** This function and xPhraseNextColumn() are similar to the xPhraseFirst()
10386 ** and xPhraseNext() APIs described above. The difference is that instead
10387 ** of iterating through all instances of a phrase in the current row, these
10388 ** APIs are used to iterate through the set of columns in the current row
10389 ** that contain one or more instances of a specified phrase. For example:
10391 ** Fts5PhraseIter iter;
10393 ** for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
10395 ** pApi->xPhraseNextColumn(pFts, &iter, &iCol)
10397 ** // Column iCol contains at least one instance of phrase iPhrase
10400 ** This API can be quite slow if used with an FTS5 table created with the
10401 ** "detail=none" option. If the FTS5 table is created with either
10402 ** "detail=none" "content=" option (i.e. if it is a contentless table),
10403 ** then this API always iterates through an empty set (all calls to
10404 ** xPhraseFirstColumn() set iCol to -1).
10406 ** The information accessed using this API and its companion
10407 ** xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
10408 ** (or xInst/xInstCount). The chief advantage of this API is that it is
10409 ** significantly more efficient than those alternatives when used with
10410 ** "detail=column" tables.
10412 ** xPhraseNextColumn()
10413 ** See xPhraseFirstColumn above.
10415 struct Fts5ExtensionApi {
10416 int iVersion; /* Currently always set to 3 */
10418 void *(*xUserData)(Fts5Context*);
10420 int (*xColumnCount)(Fts5Context*);
10421 int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
10422 int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
10424 int (*xTokenize)(Fts5Context*,
10425 const char *pText, int nText, /* Text to tokenize */
10426 void *pCtx, /* Context passed to xToken() */
10427 int (*xToken)(void*, int, const char*, int, int, int) /* Callback */
10430 int (*xPhraseCount)(Fts5Context*);
10431 int (*xPhraseSize)(Fts5Context*, int iPhrase);
10433 int (*xInstCount)(Fts5Context*, int *pnInst);
10434 int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
10436 sqlite3_int64 (*xRowid)(Fts5Context*);
10437 int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
10438 int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
10440 int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
10441 int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
10443 int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
10444 void *(*xGetAuxdata)(Fts5Context*, int bClear);
10446 int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
10447 void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
10449 int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
10450 void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
10454 ** CUSTOM AUXILIARY FUNCTIONS
10455 *************************************************************************/
10457 /*************************************************************************
10458 ** CUSTOM TOKENIZERS
10460 ** Applications may also register custom tokenizer types. A tokenizer
10461 ** is registered by providing fts5 with a populated instance of the
10462 ** following structure. All structure methods must be defined, setting
10463 ** any member of the fts5_tokenizer struct to NULL leads to undefined
10464 ** behaviour. The structure methods are expected to function as follows:
10467 ** This function is used to allocate and initialize a tokenizer instance.
10468 ** A tokenizer instance is required to actually tokenize text.
10470 ** The first argument passed to this function is a copy of the (void*)
10471 ** pointer provided by the application when the fts5_tokenizer object
10472 ** was registered with FTS5 (the third argument to xCreateTokenizer()).
10473 ** The second and third arguments are an array of nul-terminated strings
10474 ** containing the tokenizer arguments, if any, specified following the
10475 ** tokenizer name as part of the CREATE VIRTUAL TABLE statement used
10476 ** to create the FTS5 table.
10478 ** The final argument is an output variable. If successful, (*ppOut)
10479 ** should be set to point to the new tokenizer handle and SQLITE_OK
10480 ** returned. If an error occurs, some value other than SQLITE_OK should
10481 ** be returned. In this case, fts5 assumes that the final value of *ppOut
10485 ** This function is invoked to delete a tokenizer handle previously
10486 ** allocated using xCreate(). Fts5 guarantees that this function will
10487 ** be invoked exactly once for each successful call to xCreate().
10490 ** This function is expected to tokenize the nText byte string indicated
10491 ** by argument pText. pText may or may not be nul-terminated. The first
10492 ** argument passed to this function is a pointer to an Fts5Tokenizer object
10493 ** returned by an earlier call to xCreate().
10495 ** The second argument indicates the reason that FTS5 is requesting
10496 ** tokenization of the supplied text. This is always one of the following
10499 ** <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
10500 ** or removed from the FTS table. The tokenizer is being invoked to
10501 ** determine the set of tokens to add to (or delete from) the
10504 ** <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
10505 ** against the FTS index. The tokenizer is being called to tokenize
10506 ** a bareword or quoted string specified as part of the query.
10508 ** <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
10509 ** FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
10510 ** followed by a "*" character, indicating that the last token
10511 ** returned by the tokenizer will be treated as a token prefix.
10513 ** <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
10514 ** satisfy an fts5_api.xTokenize() request made by an auxiliary
10515 ** function. Or an fts5_api.xColumnSize() request made by the same
10516 ** on a columnsize=0 database.
10519 ** For each token in the input string, the supplied callback xToken() must
10520 ** be invoked. The first argument to it should be a copy of the pointer
10521 ** passed as the second argument to xTokenize(). The third and fourth
10522 ** arguments are a pointer to a buffer containing the token text, and the
10523 ** size of the token in bytes. The 4th and 5th arguments are the byte offsets
10524 ** of the first byte of and first byte immediately following the text from
10525 ** which the token is derived within the input.
10527 ** The second argument passed to the xToken() callback ("tflags") should
10528 ** normally be set to 0. The exception is if the tokenizer supports
10529 ** synonyms. In this case see the discussion below for details.
10531 ** FTS5 assumes the xToken() callback is invoked for each token in the
10532 ** order that they occur within the input text.
10534 ** If an xToken() callback returns any value other than SQLITE_OK, then
10535 ** the tokenization should be abandoned and the xTokenize() method should
10536 ** immediately return a copy of the xToken() return value. Or, if the
10537 ** input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
10538 ** if an error occurs with the xTokenize() implementation itself, it
10539 ** may abandon the tokenization and return any error code other than
10540 ** SQLITE_OK or SQLITE_DONE.
10544 ** Custom tokenizers may also support synonyms. Consider a case in which a
10545 ** user wishes to query for a phrase such as "first place". Using the
10546 ** built-in tokenizers, the FTS5 query 'first + place' will match instances
10547 ** of "first place" within the document set, but not alternative forms
10548 ** such as "1st place". In some applications, it would be better to match
10549 ** all instances of "first place" or "1st place" regardless of which form
10550 ** the user specified in the MATCH query text.
10552 ** There are several ways to approach this in FTS5:
10554 ** <ol><li> By mapping all synonyms to a single token. In this case, the
10555 ** In the above example, this means that the tokenizer returns the
10556 ** same token for inputs "first" and "1st". Say that token is in
10557 ** fact "first", so that when the user inserts the document "I won
10558 ** 1st place" entries are added to the index for tokens "i", "won",
10559 ** "first" and "place". If the user then queries for '1st + place',
10560 ** the tokenizer substitutes "first" for "1st" and the query works
10563 ** <li> By adding multiple synonyms for a single term to the FTS index.
10564 ** In this case, when tokenizing query text, the tokenizer may
10565 ** provide multiple synonyms for a single term within the document.
10566 ** FTS5 then queries the index for each synonym individually. For
10567 ** example, faced with the query:
10570 ** ... MATCH 'first place'</codeblock>
10572 ** the tokenizer offers both "1st" and "first" as synonyms for the
10573 ** first token in the MATCH query and FTS5 effectively runs a query
10577 ** ... MATCH '(first OR 1st) place'</codeblock>
10579 ** except that, for the purposes of auxiliary functions, the query
10580 ** still appears to contain just two phrases - "(first OR 1st)"
10581 ** being treated as a single phrase.
10583 ** <li> By adding multiple synonyms for a single term to the FTS index.
10584 ** Using this method, when tokenizing document text, the tokenizer
10585 ** provides multiple synonyms for each token. So that when a
10586 ** document such as "I won first place" is tokenized, entries are
10587 ** added to the FTS index for "i", "won", "first", "1st" and
10590 ** This way, even if the tokenizer does not provide synonyms
10591 ** when tokenizing query text (it should not - to do would be
10592 ** inefficient), it doesn't matter if the user queries for
10593 ** 'first + place' or '1st + place', as there are entires in the
10594 ** FTS index corresponding to both forms of the first token.
10597 ** Whether it is parsing document or query text, any call to xToken that
10598 ** specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
10599 ** is considered to supply a synonym for the previous token. For example,
10600 ** when parsing the document "I won first place", a tokenizer that supports
10601 ** synonyms would call xToken() 5 times, as follows:
10604 ** xToken(pCtx, 0, "i", 1, 0, 1);
10605 ** xToken(pCtx, 0, "won", 3, 2, 5);
10606 ** xToken(pCtx, 0, "first", 5, 6, 11);
10607 ** xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3, 6, 11);
10608 ** xToken(pCtx, 0, "place", 5, 12, 17);
10611 ** It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
10612 ** xToken() is called. Multiple synonyms may be specified for a single token
10613 ** by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
10614 ** There is no limit to the number of synonyms that may be provided for a
10617 ** In many cases, method (1) above is the best approach. It does not add
10618 ** extra data to the FTS index or require FTS5 to query for multiple terms,
10619 ** so it is efficient in terms of disk space and query speed. However, it
10620 ** does not support prefix queries very well. If, as suggested above, the
10621 ** token "first" is subsituted for "1st" by the tokenizer, then the query:
10624 ** ... MATCH '1s*'</codeblock>
10626 ** will not match documents that contain the token "1st" (as the tokenizer
10627 ** will probably not map "1s" to any prefix of "first").
10629 ** For full prefix support, method (3) may be preferred. In this case,
10630 ** because the index contains entries for both "first" and "1st", prefix
10631 ** queries such as 'fi*' or '1s*' will match correctly. However, because
10632 ** extra entries are added to the FTS index, this method uses more space
10633 ** within the database.
10635 ** Method (2) offers a midpoint between (1) and (3). Using this method,
10636 ** a query such as '1s*' will match documents that contain the literal
10637 ** token "1st", but not "first" (assuming the tokenizer is not able to
10638 ** provide synonyms for prefixes). However, a non-prefix query like '1st'
10639 ** will match against "1st" and "first". This method does not require
10640 ** extra disk space, as no extra entries are added to the FTS index.
10641 ** On the other hand, it may require more CPU cycles to run MATCH queries,
10642 ** as separate queries of the FTS index are required for each synonym.
10644 ** When using methods (2) or (3), it is important that the tokenizer only
10645 ** provide synonyms when tokenizing document text (method (2)) or query
10646 ** text (method (3)), not both. Doing so will not cause any errors, but is
10649 typedef struct Fts5Tokenizer Fts5Tokenizer;
10650 typedef struct fts5_tokenizer fts5_tokenizer;
10651 struct fts5_tokenizer {
10652 int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
10653 void (*xDelete)(Fts5Tokenizer*);
10654 int (*xTokenize)(Fts5Tokenizer*,
10656 int flags, /* Mask of FTS5_TOKENIZE_* flags */
10657 const char *pText, int nText,
10659 void *pCtx, /* Copy of 2nd argument to xTokenize() */
10660 int tflags, /* Mask of FTS5_TOKEN_* flags */
10661 const char *pToken, /* Pointer to buffer containing token */
10662 int nToken, /* Size of token in bytes */
10663 int iStart, /* Byte offset of token within input text */
10664 int iEnd /* Byte offset of end of token within input text */
10669 /* Flags that may be passed as the third argument to xTokenize() */
10670 #define FTS5_TOKENIZE_QUERY 0x0001
10671 #define FTS5_TOKENIZE_PREFIX 0x0002
10672 #define FTS5_TOKENIZE_DOCUMENT 0x0004
10673 #define FTS5_TOKENIZE_AUX 0x0008
10675 /* Flags that may be passed by the tokenizer implementation back to FTS5
10676 ** as the third argument to the supplied xToken callback. */
10677 #define FTS5_TOKEN_COLOCATED 0x0001 /* Same position as prev. token */
10680 ** END OF CUSTOM TOKENIZERS
10681 *************************************************************************/
10683 /*************************************************************************
10684 ** FTS5 EXTENSION REGISTRATION API
10686 typedef struct fts5_api fts5_api;
10688 int iVersion; /* Currently always set to 2 */
10690 /* Create a new tokenizer */
10691 int (*xCreateTokenizer)(
10695 fts5_tokenizer *pTokenizer,
10696 void (*xDestroy)(void*)
10699 /* Find an existing tokenizer */
10700 int (*xFindTokenizer)(
10704 fts5_tokenizer *pTokenizer
10707 /* Create a new auxiliary function */
10708 int (*xCreateFunction)(
10712 fts5_extension_function xFunction,
10713 void (*xDestroy)(void*)
10718 ** END OF REGISTRATION API
10719 *************************************************************************/
10722 } /* end of the 'extern "C"' block */
10725 #endif /* _FTS5_H */
10727 /******** End of fts5.h *********/