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 "3.26.0"
127 #define SQLITE_VERSION_NUMBER 3026000
128 #define SQLITE_SOURCE_ID "2018-12-01 12:34:55 bf8c1b2b7a5960c282e543b9c293686dccff272512d08865f4600fb58238b4f9"
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_ERROR_MISSING_COLLSEQ (SQLITE_ERROR | (1<<8))
474 #define SQLITE_ERROR_RETRY (SQLITE_ERROR | (2<<8))
475 #define SQLITE_ERROR_SNAPSHOT (SQLITE_ERROR | (3<<8))
476 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
477 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
478 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
479 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
480 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
481 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
482 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
483 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
484 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
485 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
486 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
487 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
488 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
489 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
490 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
491 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
492 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
493 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
494 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
495 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
496 #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
497 #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
498 #define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
499 #define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
500 #define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8))
501 #define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8))
502 #define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8))
503 #define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8))
504 #define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8))
505 #define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8))
506 #define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8))
507 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
508 #define SQLITE_LOCKED_VTAB (SQLITE_LOCKED | (2<<8))
509 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
510 #define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8))
511 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
512 #define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
513 #define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
514 #define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8))
515 #define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
516 #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
517 #define SQLITE_CORRUPT_SEQUENCE (SQLITE_CORRUPT | (2<<8))
518 #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
519 #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
520 #define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8))
521 #define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8))
522 #define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8))
523 #define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8))
524 #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
525 #define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8))
526 #define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8))
527 #define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8))
528 #define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8))
529 #define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8))
530 #define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8))
531 #define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8))
532 #define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8))
533 #define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8))
534 #define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8))
535 #define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8))
536 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
537 #define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8))
538 #define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8))
539 #define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8))
542 ** CAPI3REF: Flags For File Open Operations
544 ** These bit values are intended for use in the
545 ** 3rd parameter to the [sqlite3_open_v2()] interface and
546 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
548 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
549 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
550 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
551 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
552 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
553 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
554 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
555 #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
556 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
557 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
558 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
559 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
560 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
561 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
562 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
563 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
564 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
565 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
566 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
567 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
569 /* Reserved: 0x00F00000 */
572 ** CAPI3REF: Device Characteristics
574 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
575 ** object returns an integer which is a vector of these
576 ** bit values expressing I/O characteristics of the mass storage
577 ** device that holds the file that the [sqlite3_io_methods]
580 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
581 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
582 ** mean that writes of blocks that are nnn bytes in size and
583 ** are aligned to an address which is an integer multiple of
584 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
585 ** that when data is appended to a file, the data is appended
586 ** first then the size of the file is extended, never the other
587 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
588 ** information is written to disk in the same order as calls
589 ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
590 ** after reboot following a crash or power loss, the only bytes in a
591 ** file that were written at the application level might have changed
592 ** and that adjacent bytes, even bytes within the same sector are
593 ** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
594 ** flag indicates that a file cannot be deleted when open. The
595 ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
596 ** read-only media and cannot be changed even by processes with
597 ** elevated privileges.
599 ** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
600 ** filesystem supports doing multiple write operations atomically when those
601 ** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
602 ** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
604 #define SQLITE_IOCAP_ATOMIC 0x00000001
605 #define SQLITE_IOCAP_ATOMIC512 0x00000002
606 #define SQLITE_IOCAP_ATOMIC1K 0x00000004
607 #define SQLITE_IOCAP_ATOMIC2K 0x00000008
608 #define SQLITE_IOCAP_ATOMIC4K 0x00000010
609 #define SQLITE_IOCAP_ATOMIC8K 0x00000020
610 #define SQLITE_IOCAP_ATOMIC16K 0x00000040
611 #define SQLITE_IOCAP_ATOMIC32K 0x00000080
612 #define SQLITE_IOCAP_ATOMIC64K 0x00000100
613 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
614 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
615 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
616 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
617 #define SQLITE_IOCAP_IMMUTABLE 0x00002000
618 #define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000
621 ** CAPI3REF: File Locking Levels
623 ** SQLite uses one of these integer values as the second
624 ** argument to calls it makes to the xLock() and xUnlock() methods
625 ** of an [sqlite3_io_methods] object.
627 #define SQLITE_LOCK_NONE 0
628 #define SQLITE_LOCK_SHARED 1
629 #define SQLITE_LOCK_RESERVED 2
630 #define SQLITE_LOCK_PENDING 3
631 #define SQLITE_LOCK_EXCLUSIVE 4
634 ** CAPI3REF: Synchronization Type Flags
636 ** When SQLite invokes the xSync() method of an
637 ** [sqlite3_io_methods] object it uses a combination of
638 ** these integer values as the second argument.
640 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
641 ** sync operation only needs to flush data to mass storage. Inode
642 ** information need not be flushed. If the lower four bits of the flag
643 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
644 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
645 ** to use Mac OS X style fullsync instead of fsync().
647 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
648 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
649 ** settings. The [synchronous pragma] determines when calls to the
650 ** xSync VFS method occur and applies uniformly across all platforms.
651 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
652 ** energetic or rigorous or forceful the sync operations are and
653 ** only make a difference on Mac OSX for the default SQLite code.
654 ** (Third-party VFS implementations might also make the distinction
655 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
656 ** operating systems natively supported by SQLite, only Mac OSX
657 ** cares about the difference.)
659 #define SQLITE_SYNC_NORMAL 0x00002
660 #define SQLITE_SYNC_FULL 0x00003
661 #define SQLITE_SYNC_DATAONLY 0x00010
664 ** CAPI3REF: OS Interface Open File Handle
666 ** An [sqlite3_file] object represents an open file in the
667 ** [sqlite3_vfs | OS interface layer]. Individual OS interface
668 ** implementations will
669 ** want to subclass this object by appending additional fields
670 ** for their own use. The pMethods entry is a pointer to an
671 ** [sqlite3_io_methods] object that defines methods for performing
672 ** I/O operations on the open file.
674 typedef struct sqlite3_file sqlite3_file;
675 struct sqlite3_file {
676 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
680 ** CAPI3REF: OS Interface File Virtual Methods Object
682 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
683 ** [sqlite3_file] object (or, more commonly, a subclass of the
684 ** [sqlite3_file] object) with a pointer to an instance of this object.
685 ** This object defines the methods used to perform various operations
686 ** against the open file represented by the [sqlite3_file] object.
688 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
689 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
690 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
691 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
692 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
695 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
696 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
697 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
698 ** flag may be ORed in to indicate that only the data of the file
699 ** and not its inode needs to be synced.
701 ** The integer values to xLock() and xUnlock() are one of
703 ** <li> [SQLITE_LOCK_NONE],
704 ** <li> [SQLITE_LOCK_SHARED],
705 ** <li> [SQLITE_LOCK_RESERVED],
706 ** <li> [SQLITE_LOCK_PENDING], or
707 ** <li> [SQLITE_LOCK_EXCLUSIVE].
709 ** xLock() increases the lock. xUnlock() decreases the lock.
710 ** The xCheckReservedLock() method checks whether any database connection,
711 ** either in this process or in some other process, is holding a RESERVED,
712 ** PENDING, or EXCLUSIVE lock on the file. It returns true
713 ** if such a lock exists and false otherwise.
715 ** The xFileControl() method is a generic interface that allows custom
716 ** VFS implementations to directly control an open file using the
717 ** [sqlite3_file_control()] interface. The second "op" argument is an
718 ** integer opcode. The third argument is a generic pointer intended to
719 ** point to a structure that may contain arguments or space in which to
720 ** write return values. Potential uses for xFileControl() might be
721 ** functions to enable blocking locks with timeouts, to change the
722 ** locking strategy (for example to use dot-file locks), to inquire
723 ** about the status of a lock, or to break stale locks. The SQLite
724 ** core reserves all opcodes less than 100 for its own use.
725 ** A [file control opcodes | list of opcodes] less than 100 is available.
726 ** Applications that define a custom xFileControl method should use opcodes
727 ** greater than 100 to avoid conflicts. VFS implementations should
728 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
731 ** The xSectorSize() method returns the sector size of the
732 ** device that underlies the file. The sector size is the
733 ** minimum write that can be performed without disturbing
734 ** other bytes in the file. The xDeviceCharacteristics()
735 ** method returns a bit vector describing behaviors of the
736 ** underlying device:
739 ** <li> [SQLITE_IOCAP_ATOMIC]
740 ** <li> [SQLITE_IOCAP_ATOMIC512]
741 ** <li> [SQLITE_IOCAP_ATOMIC1K]
742 ** <li> [SQLITE_IOCAP_ATOMIC2K]
743 ** <li> [SQLITE_IOCAP_ATOMIC4K]
744 ** <li> [SQLITE_IOCAP_ATOMIC8K]
745 ** <li> [SQLITE_IOCAP_ATOMIC16K]
746 ** <li> [SQLITE_IOCAP_ATOMIC32K]
747 ** <li> [SQLITE_IOCAP_ATOMIC64K]
748 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
749 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
750 ** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
751 ** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
752 ** <li> [SQLITE_IOCAP_IMMUTABLE]
753 ** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
756 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
757 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
758 ** mean that writes of blocks that are nnn bytes in size and
759 ** are aligned to an address which is an integer multiple of
760 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
761 ** that when data is appended to a file, the data is appended
762 ** first then the size of the file is extended, never the other
763 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
764 ** information is written to disk in the same order as calls
767 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
768 ** in the unread portions of the buffer with zeros. A VFS that
769 ** fails to zero-fill short reads might seem to work. However,
770 ** failure to zero-fill short reads will eventually lead to
771 ** database corruption.
773 typedef struct sqlite3_io_methods sqlite3_io_methods;
774 struct sqlite3_io_methods {
776 int (*xClose)(sqlite3_file*);
777 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
778 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
779 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
780 int (*xSync)(sqlite3_file*, int flags);
781 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
782 int (*xLock)(sqlite3_file*, int);
783 int (*xUnlock)(sqlite3_file*, int);
784 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
785 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
786 int (*xSectorSize)(sqlite3_file*);
787 int (*xDeviceCharacteristics)(sqlite3_file*);
788 /* Methods above are valid for version 1 */
789 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
790 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
791 void (*xShmBarrier)(sqlite3_file*);
792 int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
793 /* Methods above are valid for version 2 */
794 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
795 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
796 /* Methods above are valid for version 3 */
797 /* Additional methods may be added in future releases */
801 ** CAPI3REF: Standard File Control Opcodes
802 ** KEYWORDS: {file control opcodes} {file control opcode}
804 ** These integer constants are opcodes for the xFileControl method
805 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
809 ** <li>[[SQLITE_FCNTL_LOCKSTATE]]
810 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
811 ** opcode causes the xFileControl method to write the current state of
812 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
813 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
814 ** into an integer that the pArg argument points to. This capability
815 ** is used during testing and is only available when the SQLITE_TEST
816 ** compile-time option is used.
818 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
819 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
820 ** layer a hint of how large the database file will grow to be during the
821 ** current transaction. This hint is not guaranteed to be accurate but it
822 ** is often close. The underlying VFS might choose to preallocate database
823 ** file space based on this hint in order to help writes to the database
826 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
827 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
828 ** extends and truncates the database file in chunks of a size specified
829 ** by the user. The fourth argument to [sqlite3_file_control()] should
830 ** point to an integer (type int) containing the new chunk-size to use
831 ** for the nominated database. Allocating database file space in large
832 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
833 ** improve performance on some systems.
835 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
836 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
837 ** to the [sqlite3_file] object associated with a particular database
838 ** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER].
840 ** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
841 ** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
842 ** to the [sqlite3_file] object associated with the journal file (either
843 ** the [rollback journal] or the [write-ahead log]) for a particular database
844 ** connection. See also [SQLITE_FCNTL_FILE_POINTER].
846 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
849 ** <li>[[SQLITE_FCNTL_SYNC]]
850 ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
851 ** sent to the VFS immediately before the xSync method is invoked on a
852 ** database file descriptor. Or, if the xSync method is not invoked
853 ** because the user has configured SQLite with
854 ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
855 ** of the xSync method. In most cases, the pointer argument passed with
856 ** this file-control is NULL. However, if the database file is being synced
857 ** as part of a multi-database commit, the argument points to a nul-terminated
858 ** string containing the transactions master-journal file name. VFSes that
859 ** do not need this signal should silently ignore this opcode. Applications
860 ** should not call [sqlite3_file_control()] with this opcode as doing so may
861 ** disrupt the operation of the specialized VFSes that do require it.
863 ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
864 ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
865 ** and sent to the VFS after a transaction has been committed immediately
866 ** but before the database is unlocked. VFSes that do not need this signal
867 ** should silently ignore this opcode. Applications should not call
868 ** [sqlite3_file_control()] with this opcode as doing so may disrupt the
869 ** operation of the specialized VFSes that do require it.
871 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
872 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
873 ** retry counts and intervals for certain disk I/O operations for the
874 ** windows [VFS] in order to provide robustness in the presence of
875 ** anti-virus programs. By default, the windows VFS will retry file read,
876 ** file write, and file delete operations up to 10 times, with a delay
877 ** of 25 milliseconds before the first retry and with the delay increasing
878 ** by an additional 25 milliseconds with each subsequent retry. This
879 ** opcode allows these two values (10 retries and 25 milliseconds of delay)
880 ** to be adjusted. The values are changed for all database connections
881 ** within the same process. The argument is a pointer to an array of two
882 ** integers where the first integer is the new retry count and the second
883 ** integer is the delay. If either integer is negative, then the setting
884 ** is not changed but instead the prior value of that setting is written
885 ** into the array entry, allowing the current retry settings to be
886 ** interrogated. The zDbName parameter is ignored.
888 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
889 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
890 ** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
891 ** write ahead log ([WAL file]) and shared memory
892 ** files used for transaction control
893 ** are automatically deleted when the latest connection to the database
894 ** closes. Setting persistent WAL mode causes those files to persist after
895 ** close. Persisting the files is useful when other processes that do not
896 ** have write permission on the directory containing the database file want
897 ** to read the database file, as the WAL and shared memory files must exist
898 ** in order for the database to be readable. The fourth parameter to
899 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
900 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
901 ** WAL mode. If the integer is -1, then it is overwritten with the current
902 ** WAL persistence setting.
904 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
905 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
906 ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
907 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
908 ** xDeviceCharacteristics methods. The fourth parameter to
909 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
910 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
911 ** mode. If the integer is -1, then it is overwritten with the current
912 ** zero-damage mode setting.
914 ** <li>[[SQLITE_FCNTL_OVERWRITE]]
915 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
916 ** a write transaction to indicate that, unless it is rolled back for some
917 ** reason, the entire database file will be overwritten by the current
918 ** transaction. This is used by VACUUM operations.
920 ** <li>[[SQLITE_FCNTL_VFSNAME]]
921 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
922 ** all [VFSes] in the VFS stack. The names are of all VFS shims and the
923 ** final bottom-level VFS are written into memory obtained from
924 ** [sqlite3_malloc()] and the result is stored in the char* variable
925 ** that the fourth parameter of [sqlite3_file_control()] points to.
926 ** The caller is responsible for freeing the memory when done. As with
927 ** all file-control actions, there is no guarantee that this will actually
928 ** do anything. Callers should initialize the char* variable to a NULL
929 ** pointer in case this file-control is not implemented. This file-control
930 ** is intended for diagnostic use only.
932 ** <li>[[SQLITE_FCNTL_VFS_POINTER]]
933 ** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
934 ** [VFSes] currently in use. ^(The argument X in
935 ** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
936 ** of type "[sqlite3_vfs] **". This opcodes will set *X
937 ** to a pointer to the top-level VFS.)^
938 ** ^When there are multiple VFS shims in the stack, this opcode finds the
939 ** upper-most shim only.
941 ** <li>[[SQLITE_FCNTL_PRAGMA]]
942 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
943 ** file control is sent to the open [sqlite3_file] object corresponding
944 ** to the database file to which the pragma statement refers. ^The argument
945 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
946 ** pointers to strings (char**) in which the second element of the array
947 ** is the name of the pragma and the third element is the argument to the
948 ** pragma or NULL if the pragma has no argument. ^The handler for an
949 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
950 ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
951 ** or the equivalent and that string will become the result of the pragma or
952 ** the error message if the pragma fails. ^If the
953 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
954 ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
955 ** file control returns [SQLITE_OK], then the parser assumes that the
956 ** VFS has handled the PRAGMA itself and the parser generates a no-op
957 ** prepared statement if result string is NULL, or that returns a copy
958 ** of the result string if the string is non-NULL.
959 ** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
960 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
961 ** that the VFS encountered an error while handling the [PRAGMA] and the
962 ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
963 ** file control occurs at the beginning of pragma statement analysis and so
964 ** it is able to override built-in [PRAGMA] statements.
966 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
967 ** ^The [SQLITE_FCNTL_BUSYHANDLER]
968 ** file-control may be invoked by SQLite on the database file handle
969 ** shortly after it is opened in order to provide a custom VFS with access
970 ** to the connections busy-handler callback. The argument is of type (void **)
971 ** - an array of two (void *) values. The first (void *) actually points
972 ** to a function of type (int (*)(void *)). In order to invoke the connections
973 ** busy-handler, this function should be invoked with the second (void *) in
974 ** the array as the only argument. If it returns non-zero, then the operation
975 ** should be retried. If it returns zero, the custom VFS should abandon the
976 ** current operation.
978 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
979 ** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
980 ** to have SQLite generate a
981 ** temporary filename using the same algorithm that is followed to generate
982 ** temporary filenames for TEMP tables and other internal uses. The
983 ** argument should be a char** which will be filled with the filename
984 ** written into memory obtained from [sqlite3_malloc()]. The caller should
985 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
987 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
988 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
989 ** maximum number of bytes that will be used for memory-mapped I/O.
990 ** The argument is a pointer to a value of type sqlite3_int64 that
991 ** is an advisory maximum number of bytes in the file to memory map. The
992 ** pointer is overwritten with the old value. The limit is not changed if
993 ** the value originally pointed to is negative, and so the current limit
994 ** can be queried by passing in a pointer to a negative number. This
995 ** file-control is used internally to implement [PRAGMA mmap_size].
997 ** <li>[[SQLITE_FCNTL_TRACE]]
998 ** The [SQLITE_FCNTL_TRACE] file control provides advisory information
999 ** to the VFS about what the higher layers of the SQLite stack are doing.
1000 ** This file control is used by some VFS activity tracing [shims].
1001 ** The argument is a zero-terminated string. Higher layers in the
1002 ** SQLite stack may generate instances of this file control if
1003 ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
1005 ** <li>[[SQLITE_FCNTL_HAS_MOVED]]
1006 ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
1007 ** pointer to an integer and it writes a boolean into that integer depending
1008 ** on whether or not the file has been renamed, moved, or deleted since it
1009 ** was first opened.
1011 ** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
1012 ** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
1013 ** underlying native file handle associated with a file handle. This file
1014 ** control interprets its argument as a pointer to a native file handle and
1015 ** writes the resulting value there.
1017 ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
1018 ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This
1019 ** opcode causes the xFileControl method to swap the file handle with the one
1020 ** pointed to by the pArg argument. This capability is used during testing
1021 ** and only needs to be supported when SQLITE_TEST is defined.
1023 ** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
1024 ** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
1025 ** be advantageous to block on the next WAL lock if the lock is not immediately
1026 ** available. The WAL subsystem issues this signal during rare
1027 ** circumstances in order to fix a problem with priority inversion.
1028 ** Applications should <em>not</em> use this file-control.
1030 ** <li>[[SQLITE_FCNTL_ZIPVFS]]
1031 ** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
1032 ** VFS should return SQLITE_NOTFOUND for this opcode.
1034 ** <li>[[SQLITE_FCNTL_RBU]]
1035 ** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
1036 ** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for
1039 ** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
1040 ** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
1041 ** the file descriptor is placed in "batch write mode", which
1042 ** means all subsequent write operations will be deferred and done
1043 ** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems
1044 ** that do not support batch atomic writes will return SQLITE_NOTFOUND.
1045 ** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
1046 ** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
1047 ** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
1048 ** no VFS interface calls on the same [sqlite3_file] file descriptor
1049 ** except for calls to the xWrite method and the xFileControl method
1050 ** with [SQLITE_FCNTL_SIZE_HINT].
1052 ** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
1053 ** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
1054 ** operations since the previous successful call to
1055 ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
1056 ** This file control returns [SQLITE_OK] if and only if the writes were
1057 ** all performed successfully and have been committed to persistent storage.
1058 ** ^Regardless of whether or not it is successful, this file control takes
1059 ** the file descriptor out of batch write mode so that all subsequent
1060 ** write operations are independent.
1061 ** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
1062 ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1064 ** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
1065 ** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
1066 ** operations since the previous successful call to
1067 ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
1068 ** ^This file control takes the file descriptor out of batch write mode
1069 ** so that all subsequent write operations are independent.
1070 ** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
1071 ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1073 ** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]]
1074 ** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode causes attempts to obtain
1075 ** a file lock using the xLock or xShmLock methods of the VFS to wait
1076 ** for up to M milliseconds before failing, where M is the single
1077 ** unsigned integer parameter.
1079 ** <li>[[SQLITE_FCNTL_DATA_VERSION]]
1080 ** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
1081 ** a database file. The argument is a pointer to a 32-bit unsigned integer.
1082 ** The "data version" for the pager is written into the pointer. The
1083 ** "data version" changes whenever any change occurs to the corresponding
1084 ** database file, either through SQL statements on the same database
1085 ** connection or through transactions committed by separate database
1086 ** connections possibly in other processes. The [sqlite3_total_changes()]
1087 ** interface can be used to find if any database on the connection has changed,
1088 ** but that interface responds to changes on TEMP as well as MAIN and does
1089 ** not provide a mechanism to detect changes to MAIN only. Also, the
1090 ** [sqlite3_total_changes()] interface responds to internal changes only and
1091 ** omits changes made by other database connections. The
1092 ** [PRAGMA data_version] command provide a mechanism to detect changes to
1093 ** a single attached database that occur due to other database connections,
1094 ** but omits changes implemented by the database connection on which it is
1095 ** called. This file control is the only mechanism to detect changes that
1096 ** happen either internally or externally and that are associated with
1097 ** a particular attached database.
1100 #define SQLITE_FCNTL_LOCKSTATE 1
1101 #define SQLITE_FCNTL_GET_LOCKPROXYFILE 2
1102 #define SQLITE_FCNTL_SET_LOCKPROXYFILE 3
1103 #define SQLITE_FCNTL_LAST_ERRNO 4
1104 #define SQLITE_FCNTL_SIZE_HINT 5
1105 #define SQLITE_FCNTL_CHUNK_SIZE 6
1106 #define SQLITE_FCNTL_FILE_POINTER 7
1107 #define SQLITE_FCNTL_SYNC_OMITTED 8
1108 #define SQLITE_FCNTL_WIN32_AV_RETRY 9
1109 #define SQLITE_FCNTL_PERSIST_WAL 10
1110 #define SQLITE_FCNTL_OVERWRITE 11
1111 #define SQLITE_FCNTL_VFSNAME 12
1112 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
1113 #define SQLITE_FCNTL_PRAGMA 14
1114 #define SQLITE_FCNTL_BUSYHANDLER 15
1115 #define SQLITE_FCNTL_TEMPFILENAME 16
1116 #define SQLITE_FCNTL_MMAP_SIZE 18
1117 #define SQLITE_FCNTL_TRACE 19
1118 #define SQLITE_FCNTL_HAS_MOVED 20
1119 #define SQLITE_FCNTL_SYNC 21
1120 #define SQLITE_FCNTL_COMMIT_PHASETWO 22
1121 #define SQLITE_FCNTL_WIN32_SET_HANDLE 23
1122 #define SQLITE_FCNTL_WAL_BLOCK 24
1123 #define SQLITE_FCNTL_ZIPVFS 25
1124 #define SQLITE_FCNTL_RBU 26
1125 #define SQLITE_FCNTL_VFS_POINTER 27
1126 #define SQLITE_FCNTL_JOURNAL_POINTER 28
1127 #define SQLITE_FCNTL_WIN32_GET_HANDLE 29
1128 #define SQLITE_FCNTL_PDB 30
1129 #define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31
1130 #define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32
1131 #define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33
1132 #define SQLITE_FCNTL_LOCK_TIMEOUT 34
1133 #define SQLITE_FCNTL_DATA_VERSION 35
1135 /* deprecated names */
1136 #define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE
1137 #define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE
1138 #define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO
1142 ** CAPI3REF: Mutex Handle
1144 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
1145 ** abstract type for a mutex object. The SQLite core never looks
1146 ** at the internal representation of an [sqlite3_mutex]. It only
1147 ** deals with pointers to the [sqlite3_mutex] object.
1149 ** Mutexes are created using [sqlite3_mutex_alloc()].
1151 typedef struct sqlite3_mutex sqlite3_mutex;
1154 ** CAPI3REF: Loadable Extension Thunk
1156 ** A pointer to the opaque sqlite3_api_routines structure is passed as
1157 ** the third parameter to entry points of [loadable extensions]. This
1158 ** structure must be typedefed in order to work around compiler warnings
1159 ** on some platforms.
1161 typedef struct sqlite3_api_routines sqlite3_api_routines;
1164 ** CAPI3REF: OS Interface Object
1166 ** An instance of the sqlite3_vfs object defines the interface between
1167 ** the SQLite core and the underlying operating system. The "vfs"
1168 ** in the name of the object stands for "virtual file system". See
1169 ** the [VFS | VFS documentation] for further information.
1171 ** The VFS interface is sometimes extended by adding new methods onto
1172 ** the end. Each time such an extension occurs, the iVersion field
1173 ** is incremented. The iVersion value started out as 1 in
1174 ** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
1175 ** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
1176 ** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields
1177 ** may be appended to the sqlite3_vfs object and the iVersion value
1178 ** may increase again in future versions of SQLite.
1179 ** Note that the structure
1180 ** of the sqlite3_vfs object changes in the transition from
1181 ** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
1182 ** and yet the iVersion field was not modified.
1184 ** The szOsFile field is the size of the subclassed [sqlite3_file]
1185 ** structure used by this VFS. mxPathname is the maximum length of
1186 ** a pathname in this VFS.
1188 ** Registered sqlite3_vfs objects are kept on a linked list formed by
1189 ** the pNext pointer. The [sqlite3_vfs_register()]
1190 ** and [sqlite3_vfs_unregister()] interfaces manage this list
1191 ** in a thread-safe way. The [sqlite3_vfs_find()] interface
1192 ** searches the list. Neither the application code nor the VFS
1193 ** implementation should use the pNext pointer.
1195 ** The pNext field is the only field in the sqlite3_vfs
1196 ** structure that SQLite will ever modify. SQLite will only access
1197 ** or modify this field while holding a particular static mutex.
1198 ** The application should never modify anything within the sqlite3_vfs
1199 ** object once the object has been registered.
1201 ** The zName field holds the name of the VFS module. The name must
1202 ** be unique across all VFS modules.
1204 ** [[sqlite3_vfs.xOpen]]
1205 ** ^SQLite guarantees that the zFilename parameter to xOpen
1206 ** is either a NULL pointer or string obtained
1207 ** from xFullPathname() with an optional suffix added.
1208 ** ^If a suffix is added to the zFilename parameter, it will
1209 ** consist of a single "-" character followed by no more than
1210 ** 11 alphanumeric and/or "-" characters.
1211 ** ^SQLite further guarantees that
1212 ** the string will be valid and unchanged until xClose() is
1213 ** called. Because of the previous sentence,
1214 ** the [sqlite3_file] can safely store a pointer to the
1215 ** filename if it needs to remember the filename for some reason.
1216 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1217 ** must invent its own temporary name for the file. ^Whenever the
1218 ** xFilename parameter is NULL it will also be the case that the
1219 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1221 ** The flags argument to xOpen() includes all bits set in
1222 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
1223 ** or [sqlite3_open16()] is used, then flags includes at least
1224 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1225 ** If xOpen() opens a file read-only then it sets *pOutFlags to
1226 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
1228 ** ^(SQLite will also add one of the following flags to the xOpen()
1229 ** call, depending on the object being opened:
1232 ** <li> [SQLITE_OPEN_MAIN_DB]
1233 ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
1234 ** <li> [SQLITE_OPEN_TEMP_DB]
1235 ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
1236 ** <li> [SQLITE_OPEN_TRANSIENT_DB]
1237 ** <li> [SQLITE_OPEN_SUBJOURNAL]
1238 ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
1239 ** <li> [SQLITE_OPEN_WAL]
1242 ** The file I/O implementation can use the object type flags to
1243 ** change the way it deals with files. For example, an application
1244 ** that does not care about crash recovery or rollback might make
1245 ** the open of a journal file a no-op. Writes to this journal would
1246 ** also be no-ops, and any attempt to read the journal would return
1247 ** SQLITE_IOERR. Or the implementation might recognize that a database
1248 ** file will be doing page-aligned sector reads and writes in a random
1249 ** order and set up its I/O subsystem accordingly.
1251 ** SQLite might also add one of the following flags to the xOpen method:
1254 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
1255 ** <li> [SQLITE_OPEN_EXCLUSIVE]
1258 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1259 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1260 ** will be set for TEMP databases and their journals, transient
1261 ** databases, and subjournals.
1263 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1264 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1265 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1266 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1267 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1268 ** be created, and that it is an error if it already exists.
1269 ** It is <i>not</i> used to indicate the file should be opened
1270 ** for exclusive access.
1272 ** ^At least szOsFile bytes of memory are allocated by SQLite
1273 ** to hold the [sqlite3_file] structure passed as the third
1274 ** argument to xOpen. The xOpen method does not have to
1275 ** allocate the structure; it should just fill it in. Note that
1276 ** the xOpen method must set the sqlite3_file.pMethods to either
1277 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1278 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1279 ** element will be valid after xOpen returns regardless of the success
1280 ** or failure of the xOpen call.
1282 ** [[sqlite3_vfs.xAccess]]
1283 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1284 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1285 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1286 ** to test whether a file is at least readable. The file can be a
1289 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1290 ** output buffer xFullPathname. The exact size of the output buffer
1291 ** is also passed as a parameter to both methods. If the output buffer
1292 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1293 ** handled as a fatal error by SQLite, vfs implementations should endeavor
1294 ** to prevent this by setting mxPathname to a sufficiently large value.
1296 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1297 ** interfaces are not strictly a part of the filesystem, but they are
1298 ** included in the VFS structure for completeness.
1299 ** The xRandomness() function attempts to return nBytes bytes
1300 ** of good-quality randomness into zOut. The return value is
1301 ** the actual number of bytes of randomness obtained.
1302 ** The xSleep() method causes the calling thread to sleep for at
1303 ** least the number of microseconds given. ^The xCurrentTime()
1304 ** method returns a Julian Day Number for the current date and time as
1305 ** a floating point value.
1306 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1307 ** Day Number multiplied by 86400000 (the number of milliseconds in
1309 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1310 ** date and time if that method is available (if iVersion is 2 or
1311 ** greater and the function pointer is not NULL) and will fall back
1312 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1314 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1315 ** are not used by the SQLite core. These optional interfaces are provided
1316 ** by some VFSes to facilitate testing of the VFS code. By overriding
1317 ** system calls with functions under its control, a test program can
1318 ** simulate faults and error conditions that would otherwise be difficult
1319 ** or impossible to induce. The set of system calls that can be overridden
1320 ** varies from one VFS to another, and from one version of the same VFS to the
1321 ** next. Applications that use these interfaces must be prepared for any
1322 ** or all of these interfaces to be NULL or for their behavior to change
1323 ** from one release to the next. Applications must not attempt to access
1324 ** any of these methods if the iVersion of the VFS is less than 3.
1326 typedef struct sqlite3_vfs sqlite3_vfs;
1327 typedef void (*sqlite3_syscall_ptr)(void);
1328 struct sqlite3_vfs {
1329 int iVersion; /* Structure version number (currently 3) */
1330 int szOsFile; /* Size of subclassed sqlite3_file */
1331 int mxPathname; /* Maximum file pathname length */
1332 sqlite3_vfs *pNext; /* Next registered VFS */
1333 const char *zName; /* Name of this virtual file system */
1334 void *pAppData; /* Pointer to application-specific data */
1335 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1336 int flags, int *pOutFlags);
1337 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1338 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1339 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1340 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1341 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1342 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1343 void (*xDlClose)(sqlite3_vfs*, void*);
1344 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1345 int (*xSleep)(sqlite3_vfs*, int microseconds);
1346 int (*xCurrentTime)(sqlite3_vfs*, double*);
1347 int (*xGetLastError)(sqlite3_vfs*, int, char *);
1349 ** The methods above are in version 1 of the sqlite_vfs object
1350 ** definition. Those that follow are added in version 2 or later
1352 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1354 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1355 ** Those below are for version 3 and greater.
1357 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1358 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1359 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1361 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1362 ** New fields may be appended in future versions. The iVersion
1363 ** value will increment whenever this happens.
1368 ** CAPI3REF: Flags for the xAccess VFS method
1370 ** These integer constants can be used as the third parameter to
1371 ** the xAccess method of an [sqlite3_vfs] object. They determine
1372 ** what kind of permissions the xAccess method is looking for.
1373 ** With SQLITE_ACCESS_EXISTS, the xAccess method
1374 ** simply checks whether the file exists.
1375 ** With SQLITE_ACCESS_READWRITE, the xAccess method
1376 ** checks whether the named directory is both readable and writable
1377 ** (in other words, if files can be added, removed, and renamed within
1379 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1380 ** [temp_store_directory pragma], though this could change in a future
1381 ** release of SQLite.
1382 ** With SQLITE_ACCESS_READ, the xAccess method
1383 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1384 ** currently unused, though it might be used in a future release of
1387 #define SQLITE_ACCESS_EXISTS 0
1388 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1389 #define SQLITE_ACCESS_READ 2 /* Unused */
1392 ** CAPI3REF: Flags for the xShmLock VFS method
1394 ** These integer constants define the various locking operations
1395 ** allowed by the xShmLock method of [sqlite3_io_methods]. The
1396 ** following are the only legal combinations of flags to the
1400 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1401 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1402 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1403 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1406 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1407 ** was given on the corresponding lock.
1409 ** The xShmLock method can transition between unlocked and SHARED or
1410 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1413 #define SQLITE_SHM_UNLOCK 1
1414 #define SQLITE_SHM_LOCK 2
1415 #define SQLITE_SHM_SHARED 4
1416 #define SQLITE_SHM_EXCLUSIVE 8
1419 ** CAPI3REF: Maximum xShmLock index
1421 ** The xShmLock method on [sqlite3_io_methods] may use values
1422 ** between 0 and this upper bound as its "offset" argument.
1423 ** The SQLite core will never attempt to acquire or release a
1424 ** lock outside of this range
1426 #define SQLITE_SHM_NLOCK 8
1430 ** CAPI3REF: Initialize The SQLite Library
1432 ** ^The sqlite3_initialize() routine initializes the
1433 ** SQLite library. ^The sqlite3_shutdown() routine
1434 ** deallocates any resources that were allocated by sqlite3_initialize().
1435 ** These routines are designed to aid in process initialization and
1436 ** shutdown on embedded systems. Workstation applications using
1437 ** SQLite normally do not need to invoke either of these routines.
1439 ** A call to sqlite3_initialize() is an "effective" call if it is
1440 ** the first time sqlite3_initialize() is invoked during the lifetime of
1441 ** the process, or if it is the first time sqlite3_initialize() is invoked
1442 ** following a call to sqlite3_shutdown(). ^(Only an effective call
1443 ** of sqlite3_initialize() does any initialization. All other calls
1444 ** are harmless no-ops.)^
1446 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1447 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1448 ** an effective call to sqlite3_shutdown() does any deinitialization.
1449 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1451 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1452 ** is not. The sqlite3_shutdown() interface must only be called from a
1453 ** single thread. All open [database connections] must be closed and all
1454 ** other SQLite resources must be deallocated prior to invoking
1455 ** sqlite3_shutdown().
1457 ** Among other things, ^sqlite3_initialize() will invoke
1458 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1459 ** will invoke sqlite3_os_end().
1461 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1462 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1463 ** the library (perhaps it is unable to allocate a needed resource such
1464 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1466 ** ^The sqlite3_initialize() routine is called internally by many other
1467 ** SQLite interfaces so that an application usually does not need to
1468 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1469 ** calls sqlite3_initialize() so the SQLite library will be automatically
1470 ** initialized when [sqlite3_open()] is called if it has not be initialized
1471 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1472 ** compile-time option, then the automatic calls to sqlite3_initialize()
1473 ** are omitted and the application must call sqlite3_initialize() directly
1474 ** prior to using any other SQLite interface. For maximum portability,
1475 ** it is recommended that applications always invoke sqlite3_initialize()
1476 ** directly prior to using any other SQLite interface. Future releases
1477 ** of SQLite may require this. In other words, the behavior exhibited
1478 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1479 ** default behavior in some future release of SQLite.
1481 ** The sqlite3_os_init() routine does operating-system specific
1482 ** initialization of the SQLite library. The sqlite3_os_end()
1483 ** routine undoes the effect of sqlite3_os_init(). Typical tasks
1484 ** performed by these routines include allocation or deallocation
1485 ** of static resources, initialization of global variables,
1486 ** setting up a default [sqlite3_vfs] module, or setting up
1487 ** a default configuration using [sqlite3_config()].
1489 ** The application should never invoke either sqlite3_os_init()
1490 ** or sqlite3_os_end() directly. The application should only invoke
1491 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1492 ** interface is called automatically by sqlite3_initialize() and
1493 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1494 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1495 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1496 ** When [custom builds | built for other platforms]
1497 ** (using the [SQLITE_OS_OTHER=1] compile-time
1498 ** option) the application must supply a suitable implementation for
1499 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1500 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1501 ** must return [SQLITE_OK] on success and some other [error code] upon
1504 SQLITE_API int sqlite3_initialize(void);
1505 SQLITE_API int sqlite3_shutdown(void);
1506 SQLITE_API int sqlite3_os_init(void);
1507 SQLITE_API int sqlite3_os_end(void);
1510 ** CAPI3REF: Configuring The SQLite Library
1512 ** The sqlite3_config() interface is used to make global configuration
1513 ** changes to SQLite in order to tune SQLite to the specific needs of
1514 ** the application. The default configuration is recommended for most
1515 ** applications and so this routine is usually not necessary. It is
1516 ** provided to support rare applications with unusual needs.
1518 ** <b>The sqlite3_config() interface is not threadsafe. The application
1519 ** must ensure that no other SQLite interfaces are invoked by other
1520 ** threads while sqlite3_config() is running.</b>
1522 ** The sqlite3_config() interface
1523 ** may only be invoked prior to library initialization using
1524 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1525 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1526 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1527 ** Note, however, that ^sqlite3_config() can be called as part of the
1528 ** implementation of an application-defined [sqlite3_os_init()].
1530 ** The first argument to sqlite3_config() is an integer
1531 ** [configuration option] that determines
1532 ** what property of SQLite is to be configured. Subsequent arguments
1533 ** vary depending on the [configuration option]
1534 ** in the first argument.
1536 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1537 ** ^If the option is unknown or SQLite is unable to set the option
1538 ** then this routine returns a non-zero [error code].
1540 SQLITE_API int sqlite3_config(int, ...);
1543 ** CAPI3REF: Configure database connections
1546 ** The sqlite3_db_config() interface is used to make configuration
1547 ** changes to a [database connection]. The interface is similar to
1548 ** [sqlite3_config()] except that the changes apply to a single
1549 ** [database connection] (specified in the first argument).
1551 ** The second argument to sqlite3_db_config(D,V,...) is the
1552 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1553 ** that indicates what aspect of the [database connection] is being configured.
1554 ** Subsequent arguments vary depending on the configuration verb.
1556 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1557 ** the call is considered successful.
1559 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1562 ** CAPI3REF: Memory Allocation Routines
1564 ** An instance of this object defines the interface between SQLite
1565 ** and low-level memory allocation routines.
1567 ** This object is used in only one place in the SQLite interface.
1568 ** A pointer to an instance of this object is the argument to
1569 ** [sqlite3_config()] when the configuration option is
1570 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1571 ** By creating an instance of this object
1572 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1573 ** during configuration, an application can specify an alternative
1574 ** memory allocation subsystem for SQLite to use for all of its
1575 ** dynamic memory needs.
1577 ** Note that SQLite comes with several [built-in memory allocators]
1578 ** that are perfectly adequate for the overwhelming majority of applications
1579 ** and that this object is only useful to a tiny minority of applications
1580 ** with specialized memory allocation requirements. This object is
1581 ** also used during testing of SQLite in order to specify an alternative
1582 ** memory allocator that simulates memory out-of-memory conditions in
1583 ** order to verify that SQLite recovers gracefully from such
1586 ** The xMalloc, xRealloc, and xFree methods must work like the
1587 ** malloc(), realloc() and free() functions from the standard C library.
1588 ** ^SQLite guarantees that the second argument to
1589 ** xRealloc is always a value returned by a prior call to xRoundup.
1591 ** xSize should return the allocated size of a memory allocation
1592 ** previously obtained from xMalloc or xRealloc. The allocated size
1593 ** is always at least as big as the requested size but may be larger.
1595 ** The xRoundup method returns what would be the allocated size of
1596 ** a memory allocation given a particular requested size. Most memory
1597 ** allocators round up memory allocations at least to the next multiple
1598 ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1599 ** Every memory allocation request coming in through [sqlite3_malloc()]
1600 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1601 ** that causes the corresponding memory allocation to fail.
1603 ** The xInit method initializes the memory allocator. For example,
1604 ** it might allocate any require mutexes or initialize internal data
1605 ** structures. The xShutdown method is invoked (indirectly) by
1606 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1607 ** by xInit. The pAppData pointer is used as the only parameter to
1608 ** xInit and xShutdown.
1610 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1611 ** the xInit method, so the xInit method need not be threadsafe. The
1612 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1613 ** not need to be threadsafe either. For all other methods, SQLite
1614 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1615 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1616 ** it is by default) and so the methods are automatically serialized.
1617 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1618 ** methods must be threadsafe or else make their own arrangements for
1621 ** SQLite will never invoke xInit() more than once without an intervening
1622 ** call to xShutdown().
1624 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1625 struct sqlite3_mem_methods {
1626 void *(*xMalloc)(int); /* Memory allocation function */
1627 void (*xFree)(void*); /* Free a prior allocation */
1628 void *(*xRealloc)(void*,int); /* Resize an allocation */
1629 int (*xSize)(void*); /* Return the size of an allocation */
1630 int (*xRoundup)(int); /* Round up request size to allocation size */
1631 int (*xInit)(void*); /* Initialize the memory allocator */
1632 void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1633 void *pAppData; /* Argument to xInit() and xShutdown() */
1637 ** CAPI3REF: Configuration Options
1638 ** KEYWORDS: {configuration option}
1640 ** These constants are the available integer configuration options that
1641 ** can be passed as the first argument to the [sqlite3_config()] interface.
1643 ** New configuration options may be added in future releases of SQLite.
1644 ** Existing configuration options might be discontinued. Applications
1645 ** should check the return code from [sqlite3_config()] to make sure that
1646 ** the call worked. The [sqlite3_config()] interface will return a
1647 ** non-zero [error code] if a discontinued or unsupported configuration option
1651 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1652 ** <dd>There are no arguments to this option. ^This option sets the
1653 ** [threading mode] to Single-thread. In other words, it disables
1654 ** all mutexing and puts SQLite into a mode where it can only be used
1655 ** by a single thread. ^If SQLite is compiled with
1656 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1657 ** it is not possible to change the [threading mode] from its default
1658 ** value of Single-thread and so [sqlite3_config()] will return
1659 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1660 ** configuration option.</dd>
1662 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1663 ** <dd>There are no arguments to this option. ^This option sets the
1664 ** [threading mode] to Multi-thread. In other words, it disables
1665 ** mutexing on [database connection] and [prepared statement] objects.
1666 ** The application is responsible for serializing access to
1667 ** [database connections] and [prepared statements]. But other mutexes
1668 ** are enabled so that SQLite will be safe to use in a multi-threaded
1669 ** environment as long as no two threads attempt to use the same
1670 ** [database connection] at the same time. ^If SQLite is compiled with
1671 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1672 ** it is not possible to set the Multi-thread [threading mode] and
1673 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1674 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1676 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1677 ** <dd>There are no arguments to this option. ^This option sets the
1678 ** [threading mode] to Serialized. In other words, this option enables
1679 ** all mutexes including the recursive
1680 ** mutexes on [database connection] and [prepared statement] objects.
1681 ** In this mode (which is the default when SQLite is compiled with
1682 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1683 ** to [database connections] and [prepared statements] so that the
1684 ** application is free to use the same [database connection] or the
1685 ** same [prepared statement] in different threads at the same time.
1686 ** ^If SQLite is compiled with
1687 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1688 ** it is not possible to set the Serialized [threading mode] and
1689 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1690 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1692 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1693 ** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1694 ** a pointer to an instance of the [sqlite3_mem_methods] structure.
1695 ** The argument specifies
1696 ** alternative low-level memory allocation routines to be used in place of
1697 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1698 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1699 ** before the [sqlite3_config()] call returns.</dd>
1701 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1702 ** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1703 ** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1704 ** The [sqlite3_mem_methods]
1705 ** structure is filled with the currently defined memory allocation routines.)^
1706 ** This option can be used to overload the default memory allocation
1707 ** routines with a wrapper that simulations memory allocation failure or
1708 ** tracks memory usage, for example. </dd>
1710 ** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
1711 ** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
1712 ** type int, interpreted as a boolean, which if true provides a hint to
1713 ** SQLite that it should avoid large memory allocations if possible.
1714 ** SQLite will run faster if it is free to make large memory allocations,
1715 ** but some application might prefer to run slower in exchange for
1716 ** guarantees about memory fragmentation that are possible if large
1717 ** allocations are avoided. This hint is normally off.
1720 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1721 ** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1722 ** interpreted as a boolean, which enables or disables the collection of
1723 ** memory allocation statistics. ^(When memory allocation statistics are
1724 ** disabled, the following SQLite interfaces become non-operational:
1726 ** <li> [sqlite3_memory_used()]
1727 ** <li> [sqlite3_memory_highwater()]
1728 ** <li> [sqlite3_soft_heap_limit64()]
1729 ** <li> [sqlite3_status64()]
1731 ** ^Memory allocation statistics are enabled by default unless SQLite is
1732 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1733 ** allocation statistics are disabled by default.
1736 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1737 ** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
1740 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1741 ** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
1742 ** that SQLite can use for the database page cache with the default page
1743 ** cache implementation.
1744 ** This configuration option is a no-op if an application-define page
1745 ** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
1746 ** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1747 ** 8-byte aligned memory (pMem), the size of each page cache line (sz),
1748 ** and the number of cache lines (N).
1749 ** The sz argument should be the size of the largest database page
1750 ** (a power of two between 512 and 65536) plus some extra bytes for each
1751 ** page header. ^The number of extra bytes needed by the page header
1752 ** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
1753 ** ^It is harmless, apart from the wasted memory,
1754 ** for the sz parameter to be larger than necessary. The pMem
1755 ** argument must be either a NULL pointer or a pointer to an 8-byte
1756 ** aligned block of memory of at least sz*N bytes, otherwise
1757 ** subsequent behavior is undefined.
1758 ** ^When pMem is not NULL, SQLite will strive to use the memory provided
1759 ** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
1760 ** a page cache line is larger than sz bytes or if all of the pMem buffer
1762 ** ^If pMem is NULL and N is non-zero, then each database connection
1763 ** does an initial bulk allocation for page cache memory
1764 ** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
1765 ** of -1024*N bytes if N is negative, . ^If additional
1766 ** page cache memory is needed beyond what is provided by the initial
1767 ** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
1768 ** additional cache line. </dd>
1770 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1771 ** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1772 ** that SQLite will use for all of its dynamic memory allocation needs
1773 ** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
1774 ** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1775 ** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1776 ** [SQLITE_ERROR] if invoked otherwise.
1777 ** ^There are three arguments to SQLITE_CONFIG_HEAP:
1778 ** An 8-byte aligned pointer to the memory,
1779 ** the number of bytes in the memory buffer, and the minimum allocation size.
1780 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1781 ** to using its default memory allocator (the system malloc() implementation),
1782 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1783 ** memory pointer is not NULL then the alternative memory
1784 ** allocator is engaged to handle all of SQLites memory allocation needs.
1785 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1786 ** boundary or subsequent behavior of SQLite will be undefined.
1787 ** The minimum allocation size is capped at 2**12. Reasonable values
1788 ** for the minimum allocation size are 2**5 through 2**8.</dd>
1790 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1791 ** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1792 ** pointer to an instance of the [sqlite3_mutex_methods] structure.
1793 ** The argument specifies alternative low-level mutex routines to be used
1794 ** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of
1795 ** the content of the [sqlite3_mutex_methods] structure before the call to
1796 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1797 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1798 ** the entire mutexing subsystem is omitted from the build and hence calls to
1799 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1800 ** return [SQLITE_ERROR].</dd>
1802 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1803 ** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1804 ** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The
1805 ** [sqlite3_mutex_methods]
1806 ** structure is filled with the currently defined mutex routines.)^
1807 ** This option can be used to overload the default mutex allocation
1808 ** routines with a wrapper used to track mutex usage for performance
1809 ** profiling or testing, for example. ^If SQLite is compiled with
1810 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1811 ** the entire mutexing subsystem is omitted from the build and hence calls to
1812 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1813 ** return [SQLITE_ERROR].</dd>
1815 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1816 ** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1817 ** the default size of lookaside memory on each [database connection].
1818 ** The first argument is the
1819 ** size of each lookaside buffer slot and the second is the number of
1820 ** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE
1821 ** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1822 ** option to [sqlite3_db_config()] can be used to change the lookaside
1823 ** configuration on individual connections.)^ </dd>
1825 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1826 ** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1827 ** a pointer to an [sqlite3_pcache_methods2] object. This object specifies
1828 ** the interface to a custom page cache implementation.)^
1829 ** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1831 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1832 ** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1833 ** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of
1834 ** the current page cache implementation into that object.)^ </dd>
1836 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1837 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1838 ** global [error log].
1839 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1840 ** function with a call signature of void(*)(void*,int,const char*),
1841 ** and a pointer to void. ^If the function pointer is not NULL, it is
1842 ** invoked by [sqlite3_log()] to process each logging event. ^If the
1843 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1844 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1845 ** passed through as the first parameter to the application-defined logger
1846 ** function whenever that function is invoked. ^The second parameter to
1847 ** the logger function is a copy of the first parameter to the corresponding
1848 ** [sqlite3_log()] call and is intended to be a [result code] or an
1849 ** [extended result code]. ^The third parameter passed to the logger is
1850 ** log message after formatting via [sqlite3_snprintf()].
1851 ** The SQLite logging interface is not reentrant; the logger function
1852 ** supplied by the application must not invoke any SQLite interface.
1853 ** In a multi-threaded application, the application-defined logger
1854 ** function must be threadsafe. </dd>
1856 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1857 ** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1858 ** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1859 ** then URI handling is globally disabled.)^ ^If URI handling is globally
1860 ** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1861 ** [sqlite3_open16()] or
1862 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1863 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1864 ** connection is opened. ^If it is globally disabled, filenames are
1865 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1866 ** database connection is opened. ^(By default, URI handling is globally
1867 ** disabled. The default value may be changed by compiling with the
1868 ** [SQLITE_USE_URI] symbol defined.)^
1870 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1871 ** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1872 ** argument which is interpreted as a boolean in order to enable or disable
1873 ** the use of covering indices for full table scans in the query optimizer.
1874 ** ^The default setting is determined
1875 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1876 ** if that compile-time option is omitted.
1877 ** The ability to disable the use of covering indices for full table scans
1878 ** is because some incorrectly coded legacy applications might malfunction
1879 ** when the optimization is enabled. Providing the ability to
1880 ** disable the optimization allows the older, buggy application code to work
1881 ** without change even with newer versions of SQLite.
1883 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1884 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1885 ** <dd> These options are obsolete and should not be used by new code.
1886 ** They are retained for backwards compatibility but are now no-ops.
1889 ** [[SQLITE_CONFIG_SQLLOG]]
1890 ** <dt>SQLITE_CONFIG_SQLLOG
1891 ** <dd>This option is only available if sqlite is compiled with the
1892 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1893 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1894 ** The second should be of type (void*). The callback is invoked by the library
1895 ** in three separate circumstances, identified by the value passed as the
1896 ** fourth parameter. If the fourth parameter is 0, then the database connection
1897 ** passed as the second argument has just been opened. The third argument
1898 ** points to a buffer containing the name of the main database file. If the
1899 ** fourth parameter is 1, then the SQL statement that the third parameter
1900 ** points to has just been executed. Or, if the fourth parameter is 2, then
1901 ** the connection being passed as the second parameter is being closed. The
1902 ** third parameter is passed NULL In this case. An example of using this
1903 ** configuration option can be seen in the "test_sqllog.c" source file in
1904 ** the canonical SQLite source tree.</dd>
1906 ** [[SQLITE_CONFIG_MMAP_SIZE]]
1907 ** <dt>SQLITE_CONFIG_MMAP_SIZE
1908 ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1909 ** that are the default mmap size limit (the default setting for
1910 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1911 ** ^The default setting can be overridden by each database connection using
1912 ** either the [PRAGMA mmap_size] command, or by using the
1913 ** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size
1914 ** will be silently truncated if necessary so that it does not exceed the
1915 ** compile-time maximum mmap size set by the
1916 ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1917 ** ^If either argument to this option is negative, then that argument is
1918 ** changed to its compile-time default.
1920 ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
1921 ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
1922 ** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
1923 ** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
1924 ** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1925 ** that specifies the maximum size of the created heap.
1927 ** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
1928 ** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
1929 ** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
1930 ** is a pointer to an integer and writes into that integer the number of extra
1931 ** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
1932 ** The amount of extra space required can change depending on the compiler,
1933 ** target platform, and SQLite version.
1935 ** [[SQLITE_CONFIG_PMASZ]]
1936 ** <dt>SQLITE_CONFIG_PMASZ
1937 ** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
1938 ** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
1939 ** sorter to that integer. The default minimum PMA Size is set by the
1940 ** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched
1941 ** to help with sort operations when multithreaded sorting
1942 ** is enabled (using the [PRAGMA threads] command) and the amount of content
1943 ** to be sorted exceeds the page size times the minimum of the
1944 ** [PRAGMA cache_size] setting and this value.
1946 ** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
1947 ** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
1948 ** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
1949 ** becomes the [statement journal] spill-to-disk threshold.
1950 ** [Statement journals] are held in memory until their size (in bytes)
1951 ** exceeds this threshold, at which point they are written to disk.
1952 ** Or if the threshold is -1, statement journals are always held
1953 ** exclusively in memory.
1954 ** Since many statement journals never become large, setting the spill
1955 ** threshold to a value such as 64KiB can greatly reduce the amount of
1956 ** I/O required to support statement rollback.
1957 ** The default value for this setting is controlled by the
1958 ** [SQLITE_STMTJRNL_SPILL] compile-time option.
1960 ** [[SQLITE_CONFIG_SORTERREF_SIZE]]
1961 ** <dt>SQLITE_CONFIG_SORTERREF_SIZE
1962 ** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
1963 ** of type (int) - the new value of the sorter-reference size threshold.
1964 ** Usually, when SQLite uses an external sort to order records according
1965 ** to an ORDER BY clause, all fields required by the caller are present in the
1966 ** sorted records. However, if SQLite determines based on the declared type
1967 ** of a table column that its values are likely to be very large - larger
1968 ** than the configured sorter-reference size threshold - then a reference
1969 ** is stored in each sorted record and the required column values loaded
1970 ** from the database as records are returned in sorted order. The default
1971 ** value for this option is to never use this optimization. Specifying a
1972 ** negative value for this option restores the default behaviour.
1973 ** This option is only available if SQLite is compiled with the
1974 ** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
1977 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1978 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1979 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1980 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1981 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1982 #define SQLITE_CONFIG_SCRATCH 6 /* No longer used */
1983 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1984 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1985 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1986 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1987 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1988 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1989 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1990 #define SQLITE_CONFIG_PCACHE 14 /* no-op */
1991 #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
1992 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
1993 #define SQLITE_CONFIG_URI 17 /* int */
1994 #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
1995 #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
1996 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
1997 #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
1998 #define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
1999 #define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
2000 #define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */
2001 #define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */
2002 #define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */
2003 #define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */
2004 #define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */
2007 ** CAPI3REF: Database Connection Configuration Options
2009 ** These constants are the available integer configuration options that
2010 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
2012 ** New configuration options may be added in future releases of SQLite.
2013 ** Existing configuration options might be discontinued. Applications
2014 ** should check the return code from [sqlite3_db_config()] to make sure that
2015 ** the call worked. ^The [sqlite3_db_config()] interface will return a
2016 ** non-zero [error code] if a discontinued or unsupported configuration option
2020 ** [[SQLITE_DBCONFIG_LOOKASIDE]]
2021 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
2022 ** <dd> ^This option takes three additional arguments that determine the
2023 ** [lookaside memory allocator] configuration for the [database connection].
2024 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
2025 ** pointer to a memory buffer to use for lookaside memory.
2026 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
2027 ** may be NULL in which case SQLite will allocate the
2028 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
2029 ** size of each lookaside buffer slot. ^The third argument is the number of
2030 ** slots. The size of the buffer in the first argument must be greater than
2031 ** or equal to the product of the second and third arguments. The buffer
2032 ** must be aligned to an 8-byte boundary. ^If the second argument to
2033 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
2034 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
2035 ** configuration for a database connection can only be changed when that
2036 ** connection is not currently using lookaside memory, or in other words
2037 ** when the "current value" returned by
2038 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
2039 ** Any attempt to change the lookaside memory configuration when lookaside
2040 ** memory is in use leaves the configuration unchanged and returns
2041 ** [SQLITE_BUSY].)^</dd>
2043 ** [[SQLITE_DBCONFIG_ENABLE_FKEY]]
2044 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
2045 ** <dd> ^This option is used to enable or disable the enforcement of
2046 ** [foreign key constraints]. There should be two additional arguments.
2047 ** The first argument is an integer which is 0 to disable FK enforcement,
2048 ** positive to enable FK enforcement or negative to leave FK enforcement
2049 ** unchanged. The second parameter is a pointer to an integer into which
2050 ** is written 0 or 1 to indicate whether FK enforcement is off or on
2051 ** following this call. The second parameter may be a NULL pointer, in
2052 ** which case the FK enforcement setting is not reported back. </dd>
2054 ** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]]
2055 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
2056 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
2057 ** There should be two additional arguments.
2058 ** The first argument is an integer which is 0 to disable triggers,
2059 ** positive to enable triggers or negative to leave the setting unchanged.
2060 ** The second parameter is a pointer to an integer into which
2061 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
2062 ** following this call. The second parameter may be a NULL pointer, in
2063 ** which case the trigger setting is not reported back. </dd>
2065 ** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]]
2066 ** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
2067 ** <dd> ^This option is used to enable or disable the two-argument
2068 ** version of the [fts3_tokenizer()] function which is part of the
2069 ** [FTS3] full-text search engine extension.
2070 ** There should be two additional arguments.
2071 ** The first argument is an integer which is 0 to disable fts3_tokenizer() or
2072 ** positive to enable fts3_tokenizer() or negative to leave the setting
2074 ** The second parameter is a pointer to an integer into which
2075 ** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
2076 ** following this call. The second parameter may be a NULL pointer, in
2077 ** which case the new setting is not reported back. </dd>
2079 ** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]]
2080 ** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
2081 ** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
2082 ** interface independently of the [load_extension()] SQL function.
2083 ** The [sqlite3_enable_load_extension()] API enables or disables both the
2084 ** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
2085 ** There should be two additional arguments.
2086 ** When the first argument to this interface is 1, then only the C-API is
2087 ** enabled and the SQL function remains disabled. If the first argument to
2088 ** this interface is 0, then both the C-API and the SQL function are disabled.
2089 ** If the first argument is -1, then no changes are made to state of either the
2090 ** C-API or the SQL function.
2091 ** The second parameter is a pointer to an integer into which
2092 ** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
2093 ** is disabled or enabled following this call. The second parameter may
2094 ** be a NULL pointer, in which case the new setting is not reported back.
2097 ** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
2098 ** <dd> ^This option is used to change the name of the "main" database
2099 ** schema. ^The sole argument is a pointer to a constant UTF8 string
2100 ** which will become the new schema name in place of "main". ^SQLite
2101 ** does not make a copy of the new main schema name string, so the application
2102 ** must ensure that the argument passed into this DBCONFIG option is unchanged
2103 ** until after the database connection closes.
2106 ** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]]
2107 ** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
2108 ** <dd> Usually, when a database in wal mode is closed or detached from a
2109 ** database handle, SQLite checks if this will mean that there are now no
2110 ** connections at all to the database. If so, it performs a checkpoint
2111 ** operation before closing the connection. This option may be used to
2112 ** override this behaviour. The first parameter passed to this operation
2113 ** is an integer - positive to disable checkpoints-on-close, or zero (the
2114 ** default) to enable them, and negative to leave the setting unchanged.
2115 ** The second parameter is a pointer to an integer
2116 ** into which is written 0 or 1 to indicate whether checkpoints-on-close
2117 ** have been disabled - 0 if they are not disabled, 1 if they are.
2120 ** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
2121 ** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
2122 ** the [query planner stability guarantee] (QPSG). When the QPSG is active,
2123 ** a single SQL query statement will always use the same algorithm regardless
2124 ** of values of [bound parameters].)^ The QPSG disables some query optimizations
2125 ** that look at the values of bound parameters, which can make some queries
2126 ** slower. But the QPSG has the advantage of more predictable behavior. With
2127 ** the QPSG active, SQLite will always use the same query plan in the field as
2128 ** was used during testing in the lab.
2129 ** The first argument to this setting is an integer which is 0 to disable
2130 ** the QPSG, positive to enable QPSG, or negative to leave the setting
2131 ** unchanged. The second parameter is a pointer to an integer into which
2132 ** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
2133 ** following this call.
2136 ** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
2137 ** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
2138 ** include output for any operations performed by trigger programs. This
2139 ** option is used to set or clear (the default) a flag that governs this
2140 ** behavior. The first parameter passed to this operation is an integer -
2141 ** positive to enable output for trigger programs, or zero to disable it,
2142 ** or negative to leave the setting unchanged.
2143 ** The second parameter is a pointer to an integer into which is written
2144 ** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
2145 ** it is not disabled, 1 if it is.
2148 ** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
2149 ** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
2150 ** [VACUUM] in order to reset a database back to an empty database
2151 ** with no schema and no content. The following process works even for
2152 ** a badly corrupted database file:
2154 ** <li> If the database connection is newly opened, make sure it has read the
2155 ** database schema by preparing then discarding some query against the
2156 ** database, or calling sqlite3_table_column_metadata(), ignoring any
2157 ** errors. This step is only necessary if the application desires to keep
2158 ** the database in WAL mode after the reset if it was in WAL mode before
2160 ** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
2161 ** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
2162 ** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
2164 ** Because resetting a database is destructive and irreversible, the
2165 ** process requires the use of this obscure API and multiple steps to help
2166 ** ensure that it does not happen by accident.
2168 ** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
2169 ** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
2170 ** "defensive" flag for a database connection. When the defensive
2171 ** flag is enabled, language features that allow ordinary SQL to
2172 ** deliberately corrupt the database file are disabled. The disabled
2173 ** features include but are not limited to the following:
2175 ** <li> The [PRAGMA writable_schema=ON] statement.
2176 ** <li> Writes to the [sqlite_dbpage] virtual table.
2177 ** <li> Direct writes to [shadow tables].
2182 #define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */
2183 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
2184 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
2185 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
2186 #define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
2187 #define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
2188 #define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */
2189 #define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */
2190 #define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */
2191 #define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */
2192 #define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */
2193 #define SQLITE_DBCONFIG_MAX 1010 /* Largest DBCONFIG */
2196 ** CAPI3REF: Enable Or Disable Extended Result Codes
2199 ** ^The sqlite3_extended_result_codes() routine enables or disables the
2200 ** [extended result codes] feature of SQLite. ^The extended result
2201 ** codes are disabled by default for historical compatibility.
2203 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
2206 ** CAPI3REF: Last Insert Rowid
2209 ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
2210 ** has a unique 64-bit signed
2211 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
2212 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
2213 ** names are not also used by explicitly declared columns. ^If
2214 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
2215 ** is another alias for the rowid.
2217 ** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
2218 ** the most recent successful [INSERT] into a rowid table or [virtual table]
2219 ** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
2220 ** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
2221 ** on the database connection D, then sqlite3_last_insert_rowid(D) returns
2224 ** As well as being set automatically as rows are inserted into database
2225 ** tables, the value returned by this function may be set explicitly by
2226 ** [sqlite3_set_last_insert_rowid()]
2228 ** Some virtual table implementations may INSERT rows into rowid tables as
2229 ** part of committing a transaction (e.g. to flush data accumulated in memory
2230 ** to disk). In this case subsequent calls to this function return the rowid
2231 ** associated with these internal INSERT operations, which leads to
2232 ** unintuitive results. Virtual table implementations that do write to rowid
2233 ** tables in this way can avoid this problem by restoring the original
2234 ** rowid value using [sqlite3_set_last_insert_rowid()] before returning
2235 ** control to the user.
2237 ** ^(If an [INSERT] occurs within a trigger then this routine will
2238 ** return the [rowid] of the inserted row as long as the trigger is
2239 ** running. Once the trigger program ends, the value returned
2240 ** by this routine reverts to what it was before the trigger was fired.)^
2242 ** ^An [INSERT] that fails due to a constraint violation is not a
2243 ** successful [INSERT] and does not change the value returned by this
2244 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
2245 ** and INSERT OR ABORT make no changes to the return value of this
2246 ** routine when their insertion fails. ^(When INSERT OR REPLACE
2247 ** encounters a constraint violation, it does not fail. The
2248 ** INSERT continues to completion after deleting rows that caused
2249 ** the constraint problem so INSERT OR REPLACE will always change
2250 ** the return value of this interface.)^
2252 ** ^For the purposes of this routine, an [INSERT] is considered to
2253 ** be successful even if it is subsequently rolled back.
2255 ** This function is accessible to SQL statements via the
2256 ** [last_insert_rowid() SQL function].
2258 ** If a separate thread performs a new [INSERT] on the same
2259 ** database connection while the [sqlite3_last_insert_rowid()]
2260 ** function is running and thus changes the last insert [rowid],
2261 ** then the value returned by [sqlite3_last_insert_rowid()] is
2262 ** unpredictable and might not equal either the old or the new
2263 ** last insert [rowid].
2265 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
2268 ** CAPI3REF: Set the Last Insert Rowid value.
2271 ** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
2272 ** set the value returned by calling sqlite3_last_insert_rowid(D) to R
2273 ** without inserting a row into the database.
2275 SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
2278 ** CAPI3REF: Count The Number Of Rows Modified
2281 ** ^This function returns the number of rows modified, inserted or
2282 ** deleted by the most recently completed INSERT, UPDATE or DELETE
2283 ** statement on the database connection specified by the only parameter.
2284 ** ^Executing any other type of SQL statement does not modify the value
2285 ** returned by this function.
2287 ** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
2288 ** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
2289 ** [foreign key actions] or [REPLACE] constraint resolution are not counted.
2291 ** Changes to a view that are intercepted by
2292 ** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
2293 ** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
2294 ** DELETE statement run on a view is always zero. Only changes made to real
2295 ** tables are counted.
2297 ** Things are more complicated if the sqlite3_changes() function is
2298 ** executed while a trigger program is running. This may happen if the
2299 ** program uses the [changes() SQL function], or if some other callback
2300 ** function invokes sqlite3_changes() directly. Essentially:
2303 ** <li> ^(Before entering a trigger program the value returned by
2304 ** sqlite3_changes() function is saved. After the trigger program
2305 ** has finished, the original value is restored.)^
2307 ** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
2308 ** statement sets the value returned by sqlite3_changes()
2309 ** upon completion as normal. Of course, this value will not include
2310 ** any changes performed by sub-triggers, as the sqlite3_changes()
2311 ** value will be saved and restored after each sub-trigger has run.)^
2314 ** ^This means that if the changes() SQL function (or similar) is used
2315 ** by the first INSERT, UPDATE or DELETE statement within a trigger, it
2316 ** returns the value as set when the calling statement began executing.
2317 ** ^If it is used by the second or subsequent such statement within a trigger
2318 ** program, the value returned reflects the number of rows modified by the
2319 ** previous INSERT, UPDATE or DELETE statement within the same trigger.
2321 ** If a separate thread makes changes on the same database connection
2322 ** while [sqlite3_changes()] is running then the value returned
2323 ** is unpredictable and not meaningful.
2327 ** <li> the [sqlite3_total_changes()] interface
2328 ** <li> the [count_changes pragma]
2329 ** <li> the [changes() SQL function]
2330 ** <li> the [data_version pragma]
2333 SQLITE_API int sqlite3_changes(sqlite3*);
2336 ** CAPI3REF: Total Number Of Rows Modified
2339 ** ^This function returns the total number of rows inserted, modified or
2340 ** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2341 ** since the database connection was opened, including those executed as
2342 ** part of trigger programs. ^Executing any other type of SQL statement
2343 ** does not affect the value returned by sqlite3_total_changes().
2345 ** ^Changes made as part of [foreign key actions] are included in the
2346 ** count, but those made as part of REPLACE constraint resolution are
2347 ** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2350 ** This the [sqlite3_total_changes(D)] interface only reports the number
2351 ** of rows that changed due to SQL statement run against database
2352 ** connection D. Any changes by other database connections are ignored.
2353 ** To detect changes against a database file from other database
2354 ** connections use the [PRAGMA data_version] command or the
2355 ** [SQLITE_FCNTL_DATA_VERSION] [file control].
2357 ** If a separate thread makes changes on the same database connection
2358 ** while [sqlite3_total_changes()] is running then the value
2359 ** returned is unpredictable and not meaningful.
2363 ** <li> the [sqlite3_changes()] interface
2364 ** <li> the [count_changes pragma]
2365 ** <li> the [changes() SQL function]
2366 ** <li> the [data_version pragma]
2367 ** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control]
2370 SQLITE_API int sqlite3_total_changes(sqlite3*);
2373 ** CAPI3REF: Interrupt A Long-Running Query
2376 ** ^This function causes any pending database operation to abort and
2377 ** return at its earliest opportunity. This routine is typically
2378 ** called in response to a user action such as pressing "Cancel"
2379 ** or Ctrl-C where the user wants a long query operation to halt
2382 ** ^It is safe to call this routine from a thread different from the
2383 ** thread that is currently running the database operation. But it
2384 ** is not safe to call this routine with a [database connection] that
2385 ** is closed or might close before sqlite3_interrupt() returns.
2387 ** ^If an SQL operation is very nearly finished at the time when
2388 ** sqlite3_interrupt() is called, then it might not have an opportunity
2389 ** to be interrupted and might continue to completion.
2391 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2392 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2393 ** that is inside an explicit transaction, then the entire transaction
2394 ** will be rolled back automatically.
2396 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
2397 ** SQL statements on [database connection] D complete. ^Any new SQL statements
2398 ** that are started after the sqlite3_interrupt() call and before the
2399 ** running statements reaches zero are interrupted as if they had been
2400 ** running prior to the sqlite3_interrupt() call. ^New SQL statements
2401 ** that are started after the running statement count reaches zero are
2402 ** not effected by the sqlite3_interrupt().
2403 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2404 ** SQL statements is a no-op and has no effect on SQL statements
2405 ** that are started after the sqlite3_interrupt() call returns.
2407 SQLITE_API void sqlite3_interrupt(sqlite3*);
2410 ** CAPI3REF: Determine If An SQL Statement Is Complete
2412 ** These routines are useful during command-line input to determine if the
2413 ** currently entered text seems to form a complete SQL statement or
2414 ** if additional input is needed before sending the text into
2415 ** SQLite for parsing. ^These routines return 1 if the input string
2416 ** appears to be a complete SQL statement. ^A statement is judged to be
2417 ** complete if it ends with a semicolon token and is not a prefix of a
2418 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
2419 ** string literals or quoted identifier names or comments are not
2420 ** independent tokens (they are part of the token in which they are
2421 ** embedded) and thus do not count as a statement terminator. ^Whitespace
2422 ** and comments that follow the final semicolon are ignored.
2424 ** ^These routines return 0 if the statement is incomplete. ^If a
2425 ** memory allocation fails, then SQLITE_NOMEM is returned.
2427 ** ^These routines do not parse the SQL statements thus
2428 ** will not detect syntactically incorrect SQL.
2430 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2431 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2432 ** automatically by sqlite3_complete16(). If that initialization fails,
2433 ** then the return value from sqlite3_complete16() will be non-zero
2434 ** regardless of whether or not the input SQL is complete.)^
2436 ** The input to [sqlite3_complete()] must be a zero-terminated
2439 ** The input to [sqlite3_complete16()] must be a zero-terminated
2440 ** UTF-16 string in native byte order.
2442 SQLITE_API int sqlite3_complete(const char *sql);
2443 SQLITE_API int sqlite3_complete16(const void *sql);
2446 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2447 ** KEYWORDS: {busy-handler callback} {busy handler}
2450 ** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2451 ** that might be invoked with argument P whenever
2452 ** an attempt is made to access a database table associated with
2453 ** [database connection] D when another thread
2454 ** or process has the table locked.
2455 ** The sqlite3_busy_handler() interface is used to implement
2456 ** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2458 ** ^If the busy callback is NULL, then [SQLITE_BUSY]
2459 ** is returned immediately upon encountering the lock. ^If the busy callback
2460 ** is not NULL, then the callback might be invoked with two arguments.
2462 ** ^The first argument to the busy handler is a copy of the void* pointer which
2463 ** is the third argument to sqlite3_busy_handler(). ^The second argument to
2464 ** the busy handler callback is the number of times that the busy handler has
2465 ** been invoked previously for the same locking event. ^If the
2466 ** busy callback returns 0, then no additional attempts are made to
2467 ** access the database and [SQLITE_BUSY] is returned
2468 ** to the application.
2469 ** ^If the callback returns non-zero, then another attempt
2470 ** is made to access the database and the cycle repeats.
2472 ** The presence of a busy handler does not guarantee that it will be invoked
2473 ** when there is lock contention. ^If SQLite determines that invoking the busy
2474 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2475 ** to the application instead of invoking the
2477 ** Consider a scenario where one process is holding a read lock that
2478 ** it is trying to promote to a reserved lock and
2479 ** a second process is holding a reserved lock that it is trying
2480 ** to promote to an exclusive lock. The first process cannot proceed
2481 ** because it is blocked by the second and the second process cannot
2482 ** proceed because it is blocked by the first. If both processes
2483 ** invoke the busy handlers, neither will make any progress. Therefore,
2484 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2485 ** will induce the first process to release its read lock and allow
2486 ** the second process to proceed.
2488 ** ^The default busy callback is NULL.
2490 ** ^(There can only be a single busy handler defined for each
2491 ** [database connection]. Setting a new busy handler clears any
2492 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
2493 ** or evaluating [PRAGMA busy_timeout=N] will change the
2494 ** busy handler and thus clear any previously set busy handler.
2496 ** The busy callback should not take any actions which modify the
2497 ** database connection that invoked the busy handler. In other words,
2498 ** the busy handler is not reentrant. Any such actions
2499 ** result in undefined behavior.
2501 ** A busy handler must not close the database connection
2502 ** or [prepared statement] that invoked the busy handler.
2504 SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
2507 ** CAPI3REF: Set A Busy Timeout
2510 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2511 ** for a specified amount of time when a table is locked. ^The handler
2512 ** will sleep multiple times until at least "ms" milliseconds of sleeping
2513 ** have accumulated. ^After at least "ms" milliseconds of sleeping,
2514 ** the handler returns 0 which causes [sqlite3_step()] to return
2517 ** ^Calling this routine with an argument less than or equal to zero
2518 ** turns off all busy handlers.
2520 ** ^(There can only be a single busy handler for a particular
2521 ** [database connection] at any given moment. If another busy handler
2522 ** was defined (using [sqlite3_busy_handler()]) prior to calling
2523 ** this routine, that other busy handler is cleared.)^
2525 ** See also: [PRAGMA busy_timeout]
2527 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2530 ** CAPI3REF: Convenience Routines For Running Queries
2533 ** This is a legacy interface that is preserved for backwards compatibility.
2534 ** Use of this interface is not recommended.
2536 ** Definition: A <b>result table</b> is memory data structure created by the
2537 ** [sqlite3_get_table()] interface. A result table records the
2538 ** complete query results from one or more queries.
2540 ** The table conceptually has a number of rows and columns. But
2541 ** these numbers are not part of the result table itself. These
2542 ** numbers are obtained separately. Let N be the number of rows
2543 ** and M be the number of columns.
2545 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2546 ** There are (N+1)*M elements in the array. The first M pointers point
2547 ** to zero-terminated strings that contain the names of the columns.
2548 ** The remaining entries all point to query results. NULL values result
2549 ** in NULL pointers. All other values are in their UTF-8 zero-terminated
2550 ** string representation as returned by [sqlite3_column_text()].
2552 ** A result table might consist of one or more memory allocations.
2553 ** It is not safe to pass a result table directly to [sqlite3_free()].
2554 ** A result table should be deallocated using [sqlite3_free_table()].
2556 ** ^(As an example of the result table format, suppose a query result
2559 ** <blockquote><pre>
2561 ** -----------------------
2565 ** </pre></blockquote>
2567 ** There are two column (M==2) and three rows (N==3). Thus the
2568 ** result table has 8 entries. Suppose the result table is stored
2569 ** in an array names azResult. Then azResult holds this content:
2571 ** <blockquote><pre>
2572 ** azResult[0] = "Name";
2573 ** azResult[1] = "Age";
2574 ** azResult[2] = "Alice";
2575 ** azResult[3] = "43";
2576 ** azResult[4] = "Bob";
2577 ** azResult[5] = "28";
2578 ** azResult[6] = "Cindy";
2579 ** azResult[7] = "21";
2580 ** </pre></blockquote>)^
2582 ** ^The sqlite3_get_table() function evaluates one or more
2583 ** semicolon-separated SQL statements in the zero-terminated UTF-8
2584 ** string of its 2nd parameter and returns a result table to the
2585 ** pointer given in its 3rd parameter.
2587 ** After the application has finished with the result from sqlite3_get_table(),
2588 ** it must pass the result table pointer to sqlite3_free_table() in order to
2589 ** release the memory that was malloced. Because of the way the
2590 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2591 ** function must not try to call [sqlite3_free()] directly. Only
2592 ** [sqlite3_free_table()] is able to release the memory properly and safely.
2594 ** The sqlite3_get_table() interface is implemented as a wrapper around
2595 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
2596 ** to any internal data structures of SQLite. It uses only the public
2597 ** interface defined here. As a consequence, errors that occur in the
2598 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2599 ** reflected in subsequent calls to [sqlite3_errcode()] or
2600 ** [sqlite3_errmsg()].
2602 SQLITE_API int sqlite3_get_table(
2603 sqlite3 *db, /* An open database */
2604 const char *zSql, /* SQL to be evaluated */
2605 char ***pazResult, /* Results of the query */
2606 int *pnRow, /* Number of result rows written here */
2607 int *pnColumn, /* Number of result columns written here */
2608 char **pzErrmsg /* Error msg written here */
2610 SQLITE_API void sqlite3_free_table(char **result);
2613 ** CAPI3REF: Formatted String Printing Functions
2615 ** These routines are work-alikes of the "printf()" family of functions
2616 ** from the standard C library.
2617 ** These routines understand most of the common formatting options from
2618 ** the standard library printf()
2619 ** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
2620 ** See the [built-in printf()] documentation for details.
2622 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2623 ** results into memory obtained from [sqlite3_malloc64()].
2624 ** The strings returned by these two routines should be
2625 ** released by [sqlite3_free()]. ^Both routines return a
2626 ** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
2627 ** memory to hold the resulting string.
2629 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2630 ** the standard C library. The result is written into the
2631 ** buffer supplied as the second parameter whose size is given by
2632 ** the first parameter. Note that the order of the
2633 ** first two parameters is reversed from snprintf().)^ This is an
2634 ** historical accident that cannot be fixed without breaking
2635 ** backwards compatibility. ^(Note also that sqlite3_snprintf()
2636 ** returns a pointer to its buffer instead of the number of
2637 ** characters actually written into the buffer.)^ We admit that
2638 ** the number of characters written would be a more useful return
2639 ** value but we cannot change the implementation of sqlite3_snprintf()
2640 ** now without breaking compatibility.
2642 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2643 ** guarantees that the buffer is always zero-terminated. ^The first
2644 ** parameter "n" is the total size of the buffer, including space for
2645 ** the zero terminator. So the longest string that can be completely
2646 ** written will be n-1 characters.
2648 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2650 ** See also: [built-in printf()], [printf() SQL function]
2652 SQLITE_API char *sqlite3_mprintf(const char*,...);
2653 SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2654 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2655 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2658 ** CAPI3REF: Memory Allocation Subsystem
2660 ** The SQLite core uses these three routines for all of its own
2661 ** internal memory allocation needs. "Core" in the previous sentence
2662 ** does not include operating-system specific VFS implementation. The
2663 ** Windows VFS uses native malloc() and free() for some operations.
2665 ** ^The sqlite3_malloc() routine returns a pointer to a block
2666 ** of memory at least N bytes in length, where N is the parameter.
2667 ** ^If sqlite3_malloc() is unable to obtain sufficient free
2668 ** memory, it returns a NULL pointer. ^If the parameter N to
2669 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2672 ** ^The sqlite3_malloc64(N) routine works just like
2673 ** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2674 ** of a signed 32-bit integer.
2676 ** ^Calling sqlite3_free() with a pointer previously returned
2677 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2678 ** that it might be reused. ^The sqlite3_free() routine is
2679 ** a no-op if is called with a NULL pointer. Passing a NULL pointer
2680 ** to sqlite3_free() is harmless. After being freed, memory
2681 ** should neither be read nor written. Even reading previously freed
2682 ** memory might result in a segmentation fault or other severe error.
2683 ** Memory corruption, a segmentation fault, or other severe error
2684 ** might result if sqlite3_free() is called with a non-NULL pointer that
2685 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2687 ** ^The sqlite3_realloc(X,N) interface attempts to resize a
2688 ** prior memory allocation X to be at least N bytes.
2689 ** ^If the X parameter to sqlite3_realloc(X,N)
2690 ** is a NULL pointer then its behavior is identical to calling
2691 ** sqlite3_malloc(N).
2692 ** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2693 ** negative then the behavior is exactly the same as calling
2695 ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2696 ** of at least N bytes in size or NULL if insufficient memory is available.
2697 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2698 ** of the prior allocation are copied into the beginning of buffer returned
2699 ** by sqlite3_realloc(X,N) and the prior allocation is freed.
2700 ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2701 ** prior allocation is not freed.
2703 ** ^The sqlite3_realloc64(X,N) interfaces works the same as
2704 ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2705 ** of a 32-bit signed integer.
2707 ** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2708 ** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2709 ** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2710 ** ^The value returned by sqlite3_msize(X) might be larger than the number
2711 ** of bytes requested when X was allocated. ^If X is a NULL pointer then
2712 ** sqlite3_msize(X) returns zero. If X points to something that is not
2713 ** the beginning of memory allocation, or if it points to a formerly
2714 ** valid memory allocation that has now been freed, then the behavior
2715 ** of sqlite3_msize(X) is undefined and possibly harmful.
2717 ** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2718 ** sqlite3_malloc64(), and sqlite3_realloc64()
2719 ** is always aligned to at least an 8 byte boundary, or to a
2720 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2723 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2724 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2725 ** implementation of these routines to be omitted. That capability
2726 ** is no longer provided. Only built-in memory allocators can be used.
2728 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2729 ** the system malloc() and free() directly when converting
2730 ** filenames between the UTF-8 encoding used by SQLite
2731 ** and whatever filename encoding is used by the particular Windows
2732 ** installation. Memory allocation errors were detected, but
2733 ** they were reported back as [SQLITE_CANTOPEN] or
2734 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2736 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2737 ** must be either NULL or else pointers obtained from a prior
2738 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2739 ** not yet been released.
2741 ** The application must not read or write any part of
2742 ** a block of memory after it has been released using
2743 ** [sqlite3_free()] or [sqlite3_realloc()].
2745 SQLITE_API void *sqlite3_malloc(int);
2746 SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
2747 SQLITE_API void *sqlite3_realloc(void*, int);
2748 SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
2749 SQLITE_API void sqlite3_free(void*);
2750 SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
2753 ** CAPI3REF: Memory Allocator Statistics
2755 ** SQLite provides these two interfaces for reporting on the status
2756 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2757 ** routines, which form the built-in memory allocation subsystem.
2759 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2760 ** of memory currently outstanding (malloced but not freed).
2761 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2762 ** value of [sqlite3_memory_used()] since the high-water mark
2763 ** was last reset. ^The values returned by [sqlite3_memory_used()] and
2764 ** [sqlite3_memory_highwater()] include any overhead
2765 ** added by SQLite in its implementation of [sqlite3_malloc()],
2766 ** but not overhead added by the any underlying system library
2767 ** routines that [sqlite3_malloc()] may call.
2769 ** ^The memory high-water mark is reset to the current value of
2770 ** [sqlite3_memory_used()] if and only if the parameter to
2771 ** [sqlite3_memory_highwater()] is true. ^The value returned
2772 ** by [sqlite3_memory_highwater(1)] is the high-water mark
2773 ** prior to the reset.
2775 SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2776 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2779 ** CAPI3REF: Pseudo-Random Number Generator
2781 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2782 ** select random [ROWID | ROWIDs] when inserting new records into a table that
2783 ** already uses the largest possible [ROWID]. The PRNG is also used for
2784 ** the build-in random() and randomblob() SQL functions. This interface allows
2785 ** applications to access the same PRNG for other purposes.
2787 ** ^A call to this routine stores N bytes of randomness into buffer P.
2788 ** ^The P parameter can be a NULL pointer.
2790 ** ^If this routine has not been previously called or if the previous
2791 ** call had N less than one or a NULL pointer for P, then the PRNG is
2792 ** seeded using randomness obtained from the xRandomness method of
2793 ** the default [sqlite3_vfs] object.
2794 ** ^If the previous call to this routine had an N of 1 or more and a
2795 ** non-NULL P then the pseudo-randomness is generated
2796 ** internally and without recourse to the [sqlite3_vfs] xRandomness
2799 SQLITE_API void sqlite3_randomness(int N, void *P);
2802 ** CAPI3REF: Compile-Time Authorization Callbacks
2804 ** KEYWORDS: {authorizer callback}
2806 ** ^This routine registers an authorizer callback with a particular
2807 ** [database connection], supplied in the first argument.
2808 ** ^The authorizer callback is invoked as SQL statements are being compiled
2809 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2810 ** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
2811 ** and [sqlite3_prepare16_v3()]. ^At various
2812 ** points during the compilation process, as logic is being created
2813 ** to perform various actions, the authorizer callback is invoked to
2814 ** see if those actions are allowed. ^The authorizer callback should
2815 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2816 ** specific action but allow the SQL statement to continue to be
2817 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2818 ** rejected with an error. ^If the authorizer callback returns
2819 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2820 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2821 ** the authorizer will fail with an error message.
2823 ** When the callback returns [SQLITE_OK], that means the operation
2824 ** requested is ok. ^When the callback returns [SQLITE_DENY], the
2825 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2826 ** authorizer will fail with an error message explaining that
2827 ** access is denied.
2829 ** ^The first parameter to the authorizer callback is a copy of the third
2830 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2831 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2832 ** the particular action to be authorized. ^The third through sixth parameters
2833 ** to the callback are either NULL pointers or zero-terminated strings
2834 ** that contain additional details about the action to be authorized.
2835 ** Applications must always be prepared to encounter a NULL pointer in any
2836 ** of the third through the sixth parameters of the authorization callback.
2838 ** ^If the action code is [SQLITE_READ]
2839 ** and the callback returns [SQLITE_IGNORE] then the
2840 ** [prepared statement] statement is constructed to substitute
2841 ** a NULL value in place of the table column that would have
2842 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2843 ** return can be used to deny an untrusted user access to individual
2844 ** columns of a table.
2845 ** ^When a table is referenced by a [SELECT] but no column values are
2846 ** extracted from that table (for example in a query like
2847 ** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
2848 ** is invoked once for that table with a column name that is an empty string.
2849 ** ^If the action code is [SQLITE_DELETE] and the callback returns
2850 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2851 ** [truncate optimization] is disabled and all rows are deleted individually.
2853 ** An authorizer is used when [sqlite3_prepare | preparing]
2854 ** SQL statements from an untrusted source, to ensure that the SQL statements
2855 ** do not try to access data they are not allowed to see, or that they do not
2856 ** try to execute malicious statements that damage the database. For
2857 ** example, an application may allow a user to enter arbitrary
2858 ** SQL queries for evaluation by a database. But the application does
2859 ** not want the user to be able to make arbitrary changes to the
2860 ** database. An authorizer could then be put in place while the
2861 ** user-entered SQL is being [sqlite3_prepare | prepared] that
2862 ** disallows everything except [SELECT] statements.
2864 ** Applications that need to process SQL from untrusted sources
2865 ** might also consider lowering resource limits using [sqlite3_limit()]
2866 ** and limiting database size using the [max_page_count] [PRAGMA]
2867 ** in addition to using an authorizer.
2869 ** ^(Only a single authorizer can be in place on a database connection
2870 ** at a time. Each call to sqlite3_set_authorizer overrides the
2871 ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2872 ** The authorizer is disabled by default.
2874 ** The authorizer callback must not do anything that will modify
2875 ** the database connection that invoked the authorizer callback.
2876 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2877 ** database connections for the meaning of "modify" in this paragraph.
2879 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2880 ** statement might be re-prepared during [sqlite3_step()] due to a
2881 ** schema change. Hence, the application should ensure that the
2882 ** correct authorizer callback remains in place during the [sqlite3_step()].
2884 ** ^Note that the authorizer callback is invoked only during
2885 ** [sqlite3_prepare()] or its variants. Authorization is not
2886 ** performed during statement evaluation in [sqlite3_step()], unless
2887 ** as stated in the previous paragraph, sqlite3_step() invokes
2888 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2890 SQLITE_API int sqlite3_set_authorizer(
2892 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2897 ** CAPI3REF: Authorizer Return Codes
2899 ** The [sqlite3_set_authorizer | authorizer callback function] must
2900 ** return either [SQLITE_OK] or one of these two constants in order
2901 ** to signal SQLite whether or not the action is permitted. See the
2902 ** [sqlite3_set_authorizer | authorizer documentation] for additional
2905 ** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2906 ** returned from the [sqlite3_vtab_on_conflict()] interface.
2908 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */
2909 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
2912 ** CAPI3REF: Authorizer Action Codes
2914 ** The [sqlite3_set_authorizer()] interface registers a callback function
2915 ** that is invoked to authorize certain SQL statement actions. The
2916 ** second parameter to the callback is an integer code that specifies
2917 ** what action is being authorized. These are the integer action codes that
2918 ** the authorizer callback may be passed.
2920 ** These action code values signify what kind of operation is to be
2921 ** authorized. The 3rd and 4th parameters to the authorization
2922 ** callback function will be parameters or NULL depending on which of these
2923 ** codes is used as the second parameter. ^(The 5th parameter to the
2924 ** authorizer callback is the name of the database ("main", "temp",
2925 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2926 ** is the name of the inner-most trigger or view that is responsible for
2927 ** the access attempt or NULL if this access attempt is directly from
2928 ** top-level SQL code.
2930 /******************************************* 3rd ************ 4th ***********/
2931 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
2932 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
2933 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
2934 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
2935 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
2936 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
2937 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2938 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2939 #define SQLITE_DELETE 9 /* Table Name NULL */
2940 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2941 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2942 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2943 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2944 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2945 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2946 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2947 #define SQLITE_DROP_VIEW 17 /* View Name NULL */
2948 #define SQLITE_INSERT 18 /* Table Name NULL */
2949 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2950 #define SQLITE_READ 20 /* Table Name Column Name */
2951 #define SQLITE_SELECT 21 /* NULL NULL */
2952 #define SQLITE_TRANSACTION 22 /* Operation NULL */
2953 #define SQLITE_UPDATE 23 /* Table Name Column Name */
2954 #define SQLITE_ATTACH 24 /* Filename NULL */
2955 #define SQLITE_DETACH 25 /* Database Name NULL */
2956 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2957 #define SQLITE_REINDEX 27 /* Index Name NULL */
2958 #define SQLITE_ANALYZE 28 /* Table Name NULL */
2959 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2960 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2961 #define SQLITE_FUNCTION 31 /* NULL Function Name */
2962 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2963 #define SQLITE_COPY 0 /* No longer used */
2964 #define SQLITE_RECURSIVE 33 /* NULL NULL */
2967 ** CAPI3REF: Tracing And Profiling Functions
2970 ** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
2971 ** instead of the routines described here.
2973 ** These routines register callback functions that can be used for
2974 ** tracing and profiling the execution of SQL statements.
2976 ** ^The callback function registered by sqlite3_trace() is invoked at
2977 ** various times when an SQL statement is being run by [sqlite3_step()].
2978 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2979 ** SQL statement text as the statement first begins executing.
2980 ** ^(Additional sqlite3_trace() callbacks might occur
2981 ** as each triggered subprogram is entered. The callbacks for triggers
2982 ** contain a UTF-8 SQL comment that identifies the trigger.)^
2984 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2985 ** the length of [bound parameter] expansion in the output of sqlite3_trace().
2987 ** ^The callback function registered by sqlite3_profile() is invoked
2988 ** as each SQL statement finishes. ^The profile callback contains
2989 ** the original statement text and an estimate of wall-clock time
2990 ** of how long that statement took to run. ^The profile callback
2991 ** time is in units of nanoseconds, however the current implementation
2992 ** is only capable of millisecond resolution so the six least significant
2993 ** digits in the time are meaningless. Future versions of SQLite
2994 ** might provide greater resolution on the profiler callback. The
2995 ** sqlite3_profile() function is considered experimental and is
2996 ** subject to change in future versions of SQLite.
2998 SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
2999 void(*xTrace)(void*,const char*), void*);
3000 SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
3001 void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
3004 ** CAPI3REF: SQL Trace Event Codes
3005 ** KEYWORDS: SQLITE_TRACE
3007 ** These constants identify classes of events that can be monitored
3008 ** using the [sqlite3_trace_v2()] tracing logic. The M argument
3009 ** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
3010 ** the following constants. ^The first argument to the trace callback
3011 ** is one of the following constants.
3013 ** New tracing constants may be added in future releases.
3015 ** ^A trace callback has four arguments: xCallback(T,C,P,X).
3016 ** ^The T argument is one of the integer type codes above.
3017 ** ^The C argument is a copy of the context pointer passed in as the
3018 ** fourth argument to [sqlite3_trace_v2()].
3019 ** The P and X arguments are pointers whose meanings depend on T.
3022 ** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
3023 ** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
3024 ** first begins running and possibly at other times during the
3025 ** execution of the prepared statement, such as at the start of each
3026 ** trigger subprogram. ^The P argument is a pointer to the
3027 ** [prepared statement]. ^The X argument is a pointer to a string which
3028 ** is the unexpanded SQL text of the prepared statement or an SQL comment
3029 ** that indicates the invocation of a trigger. ^The callback can compute
3030 ** the same text that would have been returned by the legacy [sqlite3_trace()]
3031 ** interface by using the X argument when X begins with "--" and invoking
3032 ** [sqlite3_expanded_sql(P)] otherwise.
3034 ** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
3035 ** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
3036 ** information as is provided by the [sqlite3_profile()] callback.
3037 ** ^The P argument is a pointer to the [prepared statement] and the
3038 ** X argument points to a 64-bit integer which is the estimated of
3039 ** the number of nanosecond that the prepared statement took to run.
3040 ** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
3042 ** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
3043 ** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
3044 ** statement generates a single row of result.
3045 ** ^The P argument is a pointer to the [prepared statement] and the
3046 ** X argument is unused.
3048 ** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
3049 ** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
3050 ** connection closes.
3051 ** ^The P argument is a pointer to the [database connection] object
3052 ** and the X argument is unused.
3055 #define SQLITE_TRACE_STMT 0x01
3056 #define SQLITE_TRACE_PROFILE 0x02
3057 #define SQLITE_TRACE_ROW 0x04
3058 #define SQLITE_TRACE_CLOSE 0x08
3061 ** CAPI3REF: SQL Trace Hook
3064 ** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
3065 ** function X against [database connection] D, using property mask M
3066 ** and context pointer P. ^If the X callback is
3067 ** NULL or if the M mask is zero, then tracing is disabled. The
3068 ** M argument should be the bitwise OR-ed combination of
3069 ** zero or more [SQLITE_TRACE] constants.
3071 ** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides
3072 ** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2().
3074 ** ^The X callback is invoked whenever any of the events identified by
3075 ** mask M occur. ^The integer return value from the callback is currently
3076 ** ignored, though this may change in future releases. Callback
3077 ** implementations should return zero to ensure future compatibility.
3079 ** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
3080 ** ^The T argument is one of the [SQLITE_TRACE]
3081 ** constants to indicate why the callback was invoked.
3082 ** ^The C argument is a copy of the context pointer.
3083 ** The P and X arguments are pointers whose meanings depend on T.
3085 ** The sqlite3_trace_v2() interface is intended to replace the legacy
3086 ** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
3089 SQLITE_API int sqlite3_trace_v2(
3092 int(*xCallback)(unsigned,void*,void*,void*),
3097 ** CAPI3REF: Query Progress Callbacks
3100 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
3101 ** function X to be invoked periodically during long running calls to
3102 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
3103 ** database connection D. An example use for this
3104 ** interface is to keep a GUI updated during a large query.
3106 ** ^The parameter P is passed through as the only parameter to the
3107 ** callback function X. ^The parameter N is the approximate number of
3108 ** [virtual machine instructions] that are evaluated between successive
3109 ** invocations of the callback X. ^If N is less than one then the progress
3110 ** handler is disabled.
3112 ** ^Only a single progress handler may be defined at one time per
3113 ** [database connection]; setting a new progress handler cancels the
3114 ** old one. ^Setting parameter X to NULL disables the progress handler.
3115 ** ^The progress handler is also disabled by setting N to a value less
3118 ** ^If the progress callback returns non-zero, the operation is
3119 ** interrupted. This feature can be used to implement a
3120 ** "Cancel" button on a GUI progress dialog box.
3122 ** The progress handler callback must not do anything that will modify
3123 ** the database connection that invoked the progress handler.
3124 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3125 ** database connections for the meaning of "modify" in this paragraph.
3128 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
3131 ** CAPI3REF: Opening A New Database Connection
3132 ** CONSTRUCTOR: sqlite3
3134 ** ^These routines open an SQLite database file as specified by the
3135 ** filename argument. ^The filename argument is interpreted as UTF-8 for
3136 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
3137 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
3138 ** returned in *ppDb, even if an error occurs. The only exception is that
3139 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
3140 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
3141 ** object.)^ ^(If the database is opened (and/or created) successfully, then
3142 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
3143 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
3144 ** an English language description of the error following a failure of any
3145 ** of the sqlite3_open() routines.
3147 ** ^The default encoding will be UTF-8 for databases created using
3148 ** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases
3149 ** created using sqlite3_open16() will be UTF-16 in the native byte order.
3151 ** Whether or not an error occurs when it is opened, resources
3152 ** associated with the [database connection] handle should be released by
3153 ** passing it to [sqlite3_close()] when it is no longer required.
3155 ** The sqlite3_open_v2() interface works like sqlite3_open()
3156 ** except that it accepts two additional parameters for additional control
3157 ** over the new database connection. ^(The flags parameter to
3158 ** sqlite3_open_v2() can take one of
3159 ** the following three values, optionally combined with the
3160 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
3161 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
3164 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
3165 ** <dd>The database is opened in read-only mode. If the database does not
3166 ** already exist, an error is returned.</dd>)^
3168 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
3169 ** <dd>The database is opened for reading and writing if possible, or reading
3170 ** only if the file is write protected by the operating system. In either
3171 ** case the database must already exist, otherwise an error is returned.</dd>)^
3173 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
3174 ** <dd>The database is opened for reading and writing, and is created if
3175 ** it does not already exist. This is the behavior that is always used for
3176 ** sqlite3_open() and sqlite3_open16().</dd>)^
3179 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
3180 ** combinations shown above optionally combined with other
3181 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
3182 ** then the behavior is undefined.
3184 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
3185 ** opens in the multi-thread [threading mode] as long as the single-thread
3186 ** mode has not been set at compile-time or start-time. ^If the
3187 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
3188 ** in the serialized [threading mode] unless single-thread was
3189 ** previously selected at compile-time or start-time.
3190 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
3191 ** eligible to use [shared cache mode], regardless of whether or not shared
3192 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
3193 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
3194 ** participate in [shared cache mode] even if it is enabled.
3196 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
3197 ** [sqlite3_vfs] object that defines the operating system interface that
3198 ** the new database connection should use. ^If the fourth parameter is
3199 ** a NULL pointer then the default [sqlite3_vfs] object is used.
3201 ** ^If the filename is ":memory:", then a private, temporary in-memory database
3202 ** is created for the connection. ^This in-memory database will vanish when
3203 ** the database connection is closed. Future versions of SQLite might
3204 ** make use of additional special filenames that begin with the ":" character.
3205 ** It is recommended that when a database filename actually does begin with
3206 ** a ":" character you should prefix the filename with a pathname such as
3207 ** "./" to avoid ambiguity.
3209 ** ^If the filename is an empty string, then a private, temporary
3210 ** on-disk database will be created. ^This private database will be
3211 ** automatically deleted as soon as the database connection is closed.
3213 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
3215 ** ^If [URI filename] interpretation is enabled, and the filename argument
3216 ** begins with "file:", then the filename is interpreted as a URI. ^URI
3217 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
3218 ** set in the third argument to sqlite3_open_v2(), or if it has
3219 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
3220 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
3221 ** URI filename interpretation is turned off
3222 ** by default, but future releases of SQLite might enable URI filename
3223 ** interpretation by default. See "[URI filenames]" for additional
3226 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
3227 ** authority, then it must be either an empty string or the string
3228 ** "localhost". ^If the authority is not an empty string or "localhost", an
3229 ** error is returned to the caller. ^The fragment component of a URI, if
3230 ** present, is ignored.
3232 ** ^SQLite uses the path component of the URI as the name of the disk file
3233 ** which contains the database. ^If the path begins with a '/' character,
3234 ** then it is interpreted as an absolute path. ^If the path does not begin
3235 ** with a '/' (meaning that the authority section is omitted from the URI)
3236 ** then the path is interpreted as a relative path.
3237 ** ^(On windows, the first component of an absolute path
3238 ** is a drive specification (e.g. "C:").)^
3240 ** [[core URI query parameters]]
3241 ** The query component of a URI may contain parameters that are interpreted
3242 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
3243 ** SQLite and its built-in [VFSes] interpret the
3244 ** following query parameters:
3247 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
3248 ** a VFS object that provides the operating system interface that should
3249 ** be used to access the database file on disk. ^If this option is set to
3250 ** an empty string the default VFS object is used. ^Specifying an unknown
3251 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
3252 ** present, then the VFS specified by the option takes precedence over
3253 ** the value passed as the fourth parameter to sqlite3_open_v2().
3255 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
3256 ** "rwc", or "memory". Attempting to set it to any other value is
3258 ** ^If "ro" is specified, then the database is opened for read-only
3259 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
3260 ** third argument to sqlite3_open_v2(). ^If the mode option is set to
3261 ** "rw", then the database is opened for read-write (but not create)
3262 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
3263 ** been set. ^Value "rwc" is equivalent to setting both
3264 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
3265 ** set to "memory" then a pure [in-memory database] that never reads
3266 ** or writes from disk is used. ^It is an error to specify a value for
3267 ** the mode parameter that is less restrictive than that specified by
3268 ** the flags passed in the third parameter to sqlite3_open_v2().
3270 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
3271 ** "private". ^Setting it to "shared" is equivalent to setting the
3272 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
3273 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
3274 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
3275 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
3276 ** a URI filename, its value overrides any behavior requested by setting
3277 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
3279 ** <li> <b>psow</b>: ^The psow parameter indicates whether or not the
3280 ** [powersafe overwrite] property does or does not apply to the
3281 ** storage media on which the database file resides.
3283 ** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
3284 ** which if set disables file locking in rollback journal modes. This
3285 ** is useful for accessing a database on a filesystem that does not
3286 ** support locking. Caution: Database corruption might result if two
3287 ** or more processes write to the same database and any one of those
3288 ** processes uses nolock=1.
3290 ** <li> <b>immutable</b>: ^The immutable parameter is a boolean query
3291 ** parameter that indicates that the database file is stored on
3292 ** read-only media. ^When immutable is set, SQLite assumes that the
3293 ** database file cannot be changed, even by a process with higher
3294 ** privilege, and so the database is opened read-only and all locking
3295 ** and change detection is disabled. Caution: Setting the immutable
3296 ** property on a database file that does in fact change can result
3297 ** in incorrect query results and/or [SQLITE_CORRUPT] errors.
3298 ** See also: [SQLITE_IOCAP_IMMUTABLE].
3302 ** ^Specifying an unknown parameter in the query component of a URI is not an
3303 ** error. Future versions of SQLite might understand additional query
3304 ** parameters. See "[query parameters with special meaning to SQLite]" for
3305 ** additional information.
3307 ** [[URI filename examples]] <h3>URI filename examples</h3>
3309 ** <table border="1" align=center cellpadding=5>
3310 ** <tr><th> URI filenames <th> Results
3311 ** <tr><td> file:data.db <td>
3312 ** Open the file "data.db" in the current directory.
3313 ** <tr><td> file:/home/fred/data.db<br>
3314 ** file:///home/fred/data.db <br>
3315 ** file://localhost/home/fred/data.db <br> <td>
3316 ** Open the database file "/home/fred/data.db".
3317 ** <tr><td> file://darkstar/home/fred/data.db <td>
3318 ** An error. "darkstar" is not a recognized authority.
3319 ** <tr><td style="white-space:nowrap">
3320 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
3321 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive
3322 ** C:. Note that the %20 escaping in this example is not strictly
3323 ** necessary - space characters can be used literally
3324 ** in URI filenames.
3325 ** <tr><td> file:data.db?mode=ro&cache=private <td>
3326 ** Open file "data.db" in the current directory for read-only access.
3327 ** Regardless of whether or not shared-cache mode is enabled by
3328 ** default, use a private cache.
3329 ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
3330 ** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
3331 ** that uses dot-files in place of posix advisory locking.
3332 ** <tr><td> file:data.db?mode=readonly <td>
3333 ** An error. "readonly" is not a valid option for the "mode" parameter.
3336 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
3337 ** query components of a URI. A hexadecimal escape sequence consists of a
3338 ** percent sign - "%" - followed by exactly two hexadecimal digits
3339 ** specifying an octet value. ^Before the path or query components of a
3340 ** URI filename are interpreted, they are encoded using UTF-8 and all
3341 ** hexadecimal escape sequences replaced by a single byte containing the
3342 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
3343 ** the results are undefined.
3345 ** <b>Note to Windows users:</b> The encoding used for the filename argument
3346 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
3347 ** codepage is currently defined. Filenames containing international
3348 ** characters must be converted to UTF-8 prior to passing them into
3349 ** sqlite3_open() or sqlite3_open_v2().
3351 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
3352 ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
3353 ** features that require the use of temporary files may fail.
3355 ** See also: [sqlite3_temp_directory]
3357 SQLITE_API int sqlite3_open(
3358 const char *filename, /* Database filename (UTF-8) */
3359 sqlite3 **ppDb /* OUT: SQLite db handle */
3361 SQLITE_API int sqlite3_open16(
3362 const void *filename, /* Database filename (UTF-16) */
3363 sqlite3 **ppDb /* OUT: SQLite db handle */
3365 SQLITE_API int sqlite3_open_v2(
3366 const char *filename, /* Database filename (UTF-8) */
3367 sqlite3 **ppDb, /* OUT: SQLite db handle */
3368 int flags, /* Flags */
3369 const char *zVfs /* Name of VFS module to use */
3373 ** CAPI3REF: Obtain Values For URI Parameters
3375 ** These are utility routines, useful to VFS implementations, that check
3376 ** to see if a database file was a URI that contained a specific query
3377 ** parameter, and if so obtains the value of that query parameter.
3379 ** If F is the database filename pointer passed into the xOpen() method of
3380 ** a VFS implementation when the flags parameter to xOpen() has one or
3381 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
3382 ** P is the name of the query parameter, then
3383 ** sqlite3_uri_parameter(F,P) returns the value of the P
3384 ** parameter if it exists or a NULL pointer if P does not appear as a
3385 ** query parameter on F. If P is a query parameter of F
3386 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3387 ** a pointer to an empty string.
3389 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3390 ** parameter and returns true (1) or false (0) according to the value
3391 ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3392 ** value of query parameter P is one of "yes", "true", or "on" in any
3393 ** case or if the value begins with a non-zero number. The
3394 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3395 ** query parameter P is one of "no", "false", or "off" in any case or
3396 ** if the value begins with a numeric zero. If P is not a query
3397 ** parameter on F or if the value of P is does not match any of the
3398 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3400 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3401 ** 64-bit signed integer and returns that integer, or D if P does not
3402 ** exist. If the value of P is something other than an integer, then
3403 ** zero is returned.
3405 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3406 ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
3407 ** is not a database file pathname pointer that SQLite passed into the xOpen
3408 ** VFS method, then the behavior of this routine is undefined and probably
3411 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3412 SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3413 SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3417 ** CAPI3REF: Error Codes And Messages
3420 ** ^If the most recent sqlite3_* API call associated with
3421 ** [database connection] D failed, then the sqlite3_errcode(D) interface
3422 ** returns the numeric [result code] or [extended result code] for that
3424 ** ^The sqlite3_extended_errcode()
3425 ** interface is the same except that it always returns the
3426 ** [extended result code] even when extended result codes are
3429 ** The values returned by sqlite3_errcode() and/or
3430 ** sqlite3_extended_errcode() might change with each API call.
3431 ** Except, there are some interfaces that are guaranteed to never
3432 ** change the value of the error code. The error-code preserving
3436 ** <li> sqlite3_errcode()
3437 ** <li> sqlite3_extended_errcode()
3438 ** <li> sqlite3_errmsg()
3439 ** <li> sqlite3_errmsg16()
3442 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3443 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
3444 ** ^(Memory to hold the error message string is managed internally.
3445 ** The application does not need to worry about freeing the result.
3446 ** However, the error string might be overwritten or deallocated by
3447 ** subsequent calls to other SQLite interface functions.)^
3449 ** ^The sqlite3_errstr() interface returns the English-language text
3450 ** that describes the [result code], as UTF-8.
3451 ** ^(Memory to hold the error message string is managed internally
3452 ** and must not be freed by the application)^.
3454 ** When the serialized [threading mode] is in use, it might be the
3455 ** case that a second error occurs on a separate thread in between
3456 ** the time of the first error and the call to these interfaces.
3457 ** When that happens, the second error will be reported since these
3458 ** interfaces always report the most recent result. To avoid
3459 ** this, each thread can obtain exclusive use of the [database connection] D
3460 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3461 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3462 ** all calls to the interfaces listed here are completed.
3464 ** If an interface fails with SQLITE_MISUSE, that means the interface
3465 ** was invoked incorrectly by the application. In that case, the
3466 ** error code and message may or may not be set.
3468 SQLITE_API int sqlite3_errcode(sqlite3 *db);
3469 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
3470 SQLITE_API const char *sqlite3_errmsg(sqlite3*);
3471 SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
3472 SQLITE_API const char *sqlite3_errstr(int);
3475 ** CAPI3REF: Prepared Statement Object
3476 ** KEYWORDS: {prepared statement} {prepared statements}
3478 ** An instance of this object represents a single SQL statement that
3479 ** has been compiled into binary form and is ready to be evaluated.
3481 ** Think of each SQL statement as a separate computer program. The
3482 ** original SQL text is source code. A prepared statement object
3483 ** is the compiled object code. All SQL must be converted into a
3484 ** prepared statement before it can be run.
3486 ** The life-cycle of a prepared statement object usually goes like this:
3489 ** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
3490 ** <li> Bind values to [parameters] using the sqlite3_bind_*()
3492 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3493 ** <li> Reset the prepared statement using [sqlite3_reset()] then go back
3494 ** to step 2. Do this zero or more times.
3495 ** <li> Destroy the object using [sqlite3_finalize()].
3498 typedef struct sqlite3_stmt sqlite3_stmt;
3501 ** CAPI3REF: Run-time Limits
3504 ** ^(This interface allows the size of various constructs to be limited
3505 ** on a connection by connection basis. The first parameter is the
3506 ** [database connection] whose limit is to be set or queried. The
3507 ** second parameter is one of the [limit categories] that define a
3508 ** class of constructs to be size limited. The third parameter is the
3509 ** new limit for that construct.)^
3511 ** ^If the new limit is a negative number, the limit is unchanged.
3512 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3513 ** [limits | hard upper bound]
3514 ** set at compile-time by a C preprocessor macro called
3515 ** [limits | SQLITE_MAX_<i>NAME</i>].
3516 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3517 ** ^Attempts to increase a limit above its hard upper bound are
3518 ** silently truncated to the hard upper bound.
3520 ** ^Regardless of whether or not the limit was changed, the
3521 ** [sqlite3_limit()] interface returns the prior value of the limit.
3522 ** ^Hence, to find the current value of a limit without changing it,
3523 ** simply invoke this interface with the third parameter set to -1.
3525 ** Run-time limits are intended for use in applications that manage
3526 ** both their own internal database and also databases that are controlled
3527 ** by untrusted external sources. An example application might be a
3528 ** web browser that has its own databases for storing history and
3529 ** separate databases controlled by JavaScript applications downloaded
3530 ** off the Internet. The internal databases can be given the
3531 ** large, default limits. Databases managed by external sources can
3532 ** be given much smaller limits designed to prevent a denial of service
3533 ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
3534 ** interface to further control untrusted SQL. The size of the database
3535 ** created by an untrusted script can be contained using the
3536 ** [max_page_count] [PRAGMA].
3538 ** New run-time limit categories may be added in future releases.
3540 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
3543 ** CAPI3REF: Run-Time Limit Categories
3544 ** KEYWORDS: {limit category} {*limit categories}
3546 ** These constants define various performance limits
3547 ** that can be lowered at run-time using [sqlite3_limit()].
3548 ** The synopsis of the meanings of the various limits is shown below.
3549 ** Additional information is available at [limits | Limits in SQLite].
3552 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3553 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3555 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3556 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3558 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3559 ** <dd>The maximum number of columns in a table definition or in the
3560 ** result set of a [SELECT] or the maximum number of columns in an index
3561 ** or in an ORDER BY or GROUP BY clause.</dd>)^
3563 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3564 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3566 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3567 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3569 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3570 ** <dd>The maximum number of instructions in a virtual machine program
3571 ** used to implement an SQL statement. If [sqlite3_prepare_v2()] or
3572 ** the equivalent tries to allocate space for more than this many opcodes
3573 ** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
3575 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3576 ** <dd>The maximum number of arguments on a function.</dd>)^
3578 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3579 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3581 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3582 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3583 ** <dd>The maximum length of the pattern argument to the [LIKE] or
3584 ** [GLOB] operators.</dd>)^
3586 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3587 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3588 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3590 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3591 ** <dd>The maximum depth of recursion for triggers.</dd>)^
3593 ** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
3594 ** <dd>The maximum number of auxiliary worker threads that a single
3595 ** [prepared statement] may start.</dd>)^
3598 #define SQLITE_LIMIT_LENGTH 0
3599 #define SQLITE_LIMIT_SQL_LENGTH 1
3600 #define SQLITE_LIMIT_COLUMN 2
3601 #define SQLITE_LIMIT_EXPR_DEPTH 3
3602 #define SQLITE_LIMIT_COMPOUND_SELECT 4
3603 #define SQLITE_LIMIT_VDBE_OP 5
3604 #define SQLITE_LIMIT_FUNCTION_ARG 6
3605 #define SQLITE_LIMIT_ATTACHED 7
3606 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
3607 #define SQLITE_LIMIT_VARIABLE_NUMBER 9
3608 #define SQLITE_LIMIT_TRIGGER_DEPTH 10
3609 #define SQLITE_LIMIT_WORKER_THREADS 11
3612 ** CAPI3REF: Prepare Flags
3614 ** These constants define various flags that can be passed into
3615 ** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
3616 ** [sqlite3_prepare16_v3()] interfaces.
3618 ** New flags may be added in future releases of SQLite.
3621 ** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
3622 ** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
3623 ** that the prepared statement will be retained for a long time and
3624 ** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
3625 ** and [sqlite3_prepare16_v3()] assume that the prepared statement will
3626 ** be used just once or at most a few times and then destroyed using
3627 ** [sqlite3_finalize()] relatively soon. The current implementation acts
3628 ** on this hint by avoiding the use of [lookaside memory] so as not to
3629 ** deplete the limited store of lookaside memory. Future versions of
3630 ** SQLite may act on this hint differently.
3632 ** [[SQLITE_PREPARE_NORMALIZE]] ^(<dt>SQLITE_PREPARE_NORMALIZE</dt>
3633 ** <dd>The SQLITE_PREPARE_NORMALIZE flag indicates that a normalized
3634 ** representation of the SQL statement should be calculated and then
3635 ** associated with the prepared statement, which can be obtained via
3636 ** the [sqlite3_normalized_sql()] interface.)^ The semantics used to
3637 ** normalize a SQL statement are unspecified and subject to change.
3638 ** At a minimum, literal values will be replaced with suitable
3642 #define SQLITE_PREPARE_PERSISTENT 0x01
3643 #define SQLITE_PREPARE_NORMALIZE 0x02
3646 ** CAPI3REF: Compiling An SQL Statement
3647 ** KEYWORDS: {SQL statement compiler}
3649 ** CONSTRUCTOR: sqlite3_stmt
3651 ** To execute an SQL statement, it must first be compiled into a byte-code
3652 ** program using one of these routines. Or, in other words, these routines
3653 ** are constructors for the [prepared statement] object.
3655 ** The preferred routine to use is [sqlite3_prepare_v2()]. The
3656 ** [sqlite3_prepare()] interface is legacy and should be avoided.
3657 ** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
3658 ** for special purposes.
3660 ** The use of the UTF-8 interfaces is preferred, as SQLite currently
3661 ** does all parsing using UTF-8. The UTF-16 interfaces are provided
3662 ** as a convenience. The UTF-16 interfaces work by converting the
3663 ** input text into UTF-8, then invoking the corresponding UTF-8 interface.
3665 ** The first argument, "db", is a [database connection] obtained from a
3666 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3667 ** [sqlite3_open16()]. The database connection must not have been closed.
3669 ** The second argument, "zSql", is the statement to be compiled, encoded
3670 ** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(),
3671 ** and sqlite3_prepare_v3()
3672 ** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
3673 ** and sqlite3_prepare16_v3() use UTF-16.
3675 ** ^If the nByte argument is negative, then zSql is read up to the
3676 ** first zero terminator. ^If nByte is positive, then it is the
3677 ** number of bytes read from zSql. ^If nByte is zero, then no prepared
3678 ** statement is generated.
3679 ** If the caller knows that the supplied string is nul-terminated, then
3680 ** there is a small performance advantage to passing an nByte parameter that
3681 ** is the number of bytes in the input string <i>including</i>
3682 ** the nul-terminator.
3684 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3685 ** past the end of the first SQL statement in zSql. These routines only
3686 ** compile the first statement in zSql, so *pzTail is left pointing to
3687 ** what remains uncompiled.
3689 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3690 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
3691 ** to NULL. ^If the input text contains no SQL (if the input is an empty
3692 ** string or a comment) then *ppStmt is set to NULL.
3693 ** The calling procedure is responsible for deleting the compiled
3694 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
3695 ** ppStmt may not be NULL.
3697 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3698 ** otherwise an [error code] is returned.
3700 ** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
3701 ** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
3702 ** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
3703 ** are retained for backwards compatibility, but their use is discouraged.
3704 ** ^In the "vX" interfaces, the prepared statement
3705 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
3706 ** original SQL text. This causes the [sqlite3_step()] interface to
3707 ** behave differently in three ways:
3711 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3712 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
3713 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3714 ** retries will occur before sqlite3_step() gives up and returns an error.
3718 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3719 ** [error codes] or [extended error codes]. ^The legacy behavior was that
3720 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3721 ** and the application would have to make a second call to [sqlite3_reset()]
3722 ** in order to find the underlying cause of the problem. With the "v2" prepare
3723 ** interfaces, the underlying reason for the error is returned immediately.
3727 ** ^If the specific value bound to [parameter | host parameter] in the
3728 ** WHERE clause might influence the choice of query plan for a statement,
3729 ** then the statement will be automatically recompiled, as if there had been
3730 ** a schema change, on the first [sqlite3_step()] call following any change
3731 ** to the [sqlite3_bind_text | bindings] of that [parameter].
3732 ** ^The specific value of WHERE-clause [parameter] might influence the
3733 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
3734 ** or [GLOB] operator or if the parameter is compared to an indexed column
3735 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3739 ** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
3740 ** the extra prepFlags parameter, which is a bit array consisting of zero or
3741 ** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The
3742 ** sqlite3_prepare_v2() interface works exactly the same as
3743 ** sqlite3_prepare_v3() with a zero prepFlags parameter.
3745 SQLITE_API int sqlite3_prepare(
3746 sqlite3 *db, /* Database handle */
3747 const char *zSql, /* SQL statement, UTF-8 encoded */
3748 int nByte, /* Maximum length of zSql in bytes. */
3749 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3750 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3752 SQLITE_API int sqlite3_prepare_v2(
3753 sqlite3 *db, /* Database handle */
3754 const char *zSql, /* SQL statement, UTF-8 encoded */
3755 int nByte, /* Maximum length of zSql in bytes. */
3756 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3757 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3759 SQLITE_API int sqlite3_prepare_v3(
3760 sqlite3 *db, /* Database handle */
3761 const char *zSql, /* SQL statement, UTF-8 encoded */
3762 int nByte, /* Maximum length of zSql in bytes. */
3763 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
3764 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3765 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3767 SQLITE_API int sqlite3_prepare16(
3768 sqlite3 *db, /* Database handle */
3769 const void *zSql, /* SQL statement, UTF-16 encoded */
3770 int nByte, /* Maximum length of zSql in bytes. */
3771 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3772 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3774 SQLITE_API int sqlite3_prepare16_v2(
3775 sqlite3 *db, /* Database handle */
3776 const void *zSql, /* SQL statement, UTF-16 encoded */
3777 int nByte, /* Maximum length of zSql in bytes. */
3778 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3779 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3781 SQLITE_API int sqlite3_prepare16_v3(
3782 sqlite3 *db, /* Database handle */
3783 const void *zSql, /* SQL statement, UTF-16 encoded */
3784 int nByte, /* Maximum length of zSql in bytes. */
3785 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
3786 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3787 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3791 ** CAPI3REF: Retrieving Statement SQL
3792 ** METHOD: sqlite3_stmt
3794 ** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
3795 ** SQL text used to create [prepared statement] P if P was
3796 ** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
3797 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
3798 ** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
3799 ** string containing the SQL text of prepared statement P with
3800 ** [bound parameters] expanded.
3801 ** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
3802 ** string containing the normalized SQL text of prepared statement P. The
3803 ** semantics used to normalize a SQL statement are unspecified and subject
3804 ** to change. At a minimum, literal values will be replaced with suitable
3807 ** ^(For example, if a prepared statement is created using the SQL
3808 ** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
3809 ** and parameter :xyz is unbound, then sqlite3_sql() will return
3810 ** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
3811 ** will return "SELECT 2345,NULL".)^
3813 ** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
3814 ** is available to hold the result, or if the result would exceed the
3815 ** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
3817 ** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
3818 ** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time
3819 ** option causes sqlite3_expanded_sql() to always return NULL.
3821 ** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
3822 ** are managed by SQLite and are automatically freed when the prepared
3823 ** statement is finalized.
3824 ** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
3825 ** is obtained from [sqlite3_malloc()] and must be free by the application
3826 ** by passing it to [sqlite3_free()].
3828 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
3829 SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
3830 SQLITE_API const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
3833 ** CAPI3REF: Determine If An SQL Statement Writes The Database
3834 ** METHOD: sqlite3_stmt
3836 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3837 ** and only if the [prepared statement] X makes no direct changes to
3838 ** the content of the database file.
3840 ** Note that [application-defined SQL functions] or
3841 ** [virtual tables] might change the database indirectly as a side effect.
3842 ** ^(For example, if an application defines a function "eval()" that
3843 ** calls [sqlite3_exec()], then the following SQL statement would
3844 ** change the database file through side-effects:
3846 ** <blockquote><pre>
3847 ** SELECT eval('DELETE FROM t1') FROM t2;
3848 ** </pre></blockquote>
3850 ** But because the [SELECT] statement does not change the database file
3851 ** directly, sqlite3_stmt_readonly() would still return true.)^
3853 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3854 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3855 ** since the statements themselves do not actually modify the database but
3856 ** rather they control the timing of when other statements modify the
3857 ** database. ^The [ATTACH] and [DETACH] statements also cause
3858 ** sqlite3_stmt_readonly() to return true since, while those statements
3859 ** change the configuration of a database connection, they do not make
3860 ** changes to the content of the database files on disk.
3861 ** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
3862 ** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
3863 ** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
3864 ** sqlite3_stmt_readonly() returns false for those commands.
3866 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3869 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3870 ** METHOD: sqlite3_stmt
3872 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3873 ** [prepared statement] S has been stepped at least once using
3874 ** [sqlite3_step(S)] but has neither run to completion (returned
3875 ** [SQLITE_DONE] from [sqlite3_step(S)]) nor
3876 ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
3877 ** interface returns false if S is a NULL pointer. If S is not a
3878 ** NULL pointer and is not a pointer to a valid [prepared statement]
3879 ** object, then the behavior is undefined and probably undesirable.
3881 ** This interface can be used in combination [sqlite3_next_stmt()]
3882 ** to locate all prepared statements associated with a database
3883 ** connection that are in need of being reset. This can be used,
3884 ** for example, in diagnostic routines to search for prepared
3885 ** statements that are holding a transaction open.
3887 SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
3890 ** CAPI3REF: Dynamically Typed Value Object
3891 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3893 ** SQLite uses the sqlite3_value object to represent all values
3894 ** that can be stored in a database table. SQLite uses dynamic typing
3895 ** for the values it stores. ^Values stored in sqlite3_value objects
3896 ** can be integers, floating point values, strings, BLOBs, or NULL.
3898 ** An sqlite3_value object may be either "protected" or "unprotected".
3899 ** Some interfaces require a protected sqlite3_value. Other interfaces
3900 ** will accept either a protected or an unprotected sqlite3_value.
3901 ** Every interface that accepts sqlite3_value arguments specifies
3902 ** whether or not it requires a protected sqlite3_value. The
3903 ** [sqlite3_value_dup()] interface can be used to construct a new
3904 ** protected sqlite3_value from an unprotected sqlite3_value.
3906 ** The terms "protected" and "unprotected" refer to whether or not
3907 ** a mutex is held. An internal mutex is held for a protected
3908 ** sqlite3_value object but no mutex is held for an unprotected
3909 ** sqlite3_value object. If SQLite is compiled to be single-threaded
3910 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3911 ** or if SQLite is run in one of reduced mutex modes
3912 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3913 ** then there is no distinction between protected and unprotected
3914 ** sqlite3_value objects and they can be used interchangeably. However,
3915 ** for maximum code portability it is recommended that applications
3916 ** still make the distinction between protected and unprotected
3917 ** sqlite3_value objects even when not strictly required.
3919 ** ^The sqlite3_value objects that are passed as parameters into the
3920 ** implementation of [application-defined SQL functions] are protected.
3921 ** ^The sqlite3_value object returned by
3922 ** [sqlite3_column_value()] is unprotected.
3923 ** Unprotected sqlite3_value objects may only be used as arguments
3924 ** to [sqlite3_result_value()], [sqlite3_bind_value()], and
3925 ** [sqlite3_value_dup()].
3926 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
3927 ** interfaces require protected sqlite3_value objects.
3929 typedef struct sqlite3_value sqlite3_value;
3932 ** CAPI3REF: SQL Function Context Object
3934 ** The context in which an SQL function executes is stored in an
3935 ** sqlite3_context object. ^A pointer to an sqlite3_context object
3936 ** is always first parameter to [application-defined SQL functions].
3937 ** The application-defined SQL function implementation will pass this
3938 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3939 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3940 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3941 ** and/or [sqlite3_set_auxdata()].
3943 typedef struct sqlite3_context sqlite3_context;
3946 ** CAPI3REF: Binding Values To Prepared Statements
3947 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3948 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3949 ** METHOD: sqlite3_stmt
3951 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3952 ** literals may be replaced by a [parameter] that matches one of following
3963 ** In the templates above, NNN represents an integer literal,
3964 ** and VVV represents an alphanumeric identifier.)^ ^The values of these
3965 ** parameters (also called "host parameter names" or "SQL parameters")
3966 ** can be set using the sqlite3_bind_*() routines defined here.
3968 ** ^The first argument to the sqlite3_bind_*() routines is always
3969 ** a pointer to the [sqlite3_stmt] object returned from
3970 ** [sqlite3_prepare_v2()] or its variants.
3972 ** ^The second argument is the index of the SQL parameter to be set.
3973 ** ^The leftmost SQL parameter has an index of 1. ^When the same named
3974 ** SQL parameter is used more than once, second and subsequent
3975 ** occurrences have the same index as the first occurrence.
3976 ** ^The index for named parameters can be looked up using the
3977 ** [sqlite3_bind_parameter_index()] API if desired. ^The index
3978 ** for "?NNN" parameters is the value of NNN.
3979 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
3980 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3982 ** ^The third argument is the value to bind to the parameter.
3983 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3984 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3985 ** is ignored and the end result is the same as sqlite3_bind_null().
3987 ** ^(In those routines that have a fourth argument, its value is the
3988 ** number of bytes in the parameter. To be clear: the value is the
3989 ** number of <u>bytes</u> in the value, not the number of characters.)^
3990 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3991 ** is negative, then the length of the string is
3992 ** the number of bytes up to the first zero terminator.
3993 ** If the fourth parameter to sqlite3_bind_blob() is negative, then
3994 ** the behavior is undefined.
3995 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3996 ** or sqlite3_bind_text16() or sqlite3_bind_text64() then
3997 ** that parameter must be the byte offset
3998 ** where the NUL terminator would occur assuming the string were NUL
3999 ** terminated. If any NUL characters occur at byte offsets less than
4000 ** the value of the fourth parameter then the resulting string value will
4001 ** contain embedded NULs. The result of expressions involving strings
4002 ** with embedded NULs is undefined.
4004 ** ^The fifth argument to the BLOB and string binding interfaces
4005 ** is a destructor used to dispose of the BLOB or
4006 ** string after SQLite has finished with it. ^The destructor is called
4007 ** to dispose of the BLOB or string even if the call to bind API fails.
4008 ** ^If the fifth argument is
4009 ** the special value [SQLITE_STATIC], then SQLite assumes that the
4010 ** information is in static, unmanaged space and does not need to be freed.
4011 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
4012 ** SQLite makes its own private copy of the data immediately, before
4013 ** the sqlite3_bind_*() routine returns.
4015 ** ^The sixth argument to sqlite3_bind_text64() must be one of
4016 ** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
4017 ** to specify the encoding of the text in the third parameter. If
4018 ** the sixth argument to sqlite3_bind_text64() is not one of the
4019 ** allowed values shown above, or if the text encoding is different
4020 ** from the encoding specified by the sixth parameter, then the behavior
4023 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
4024 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
4025 ** (just an integer to hold its size) while it is being processed.
4026 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
4027 ** content is later written using
4028 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
4029 ** ^A negative value for the zeroblob results in a zero-length BLOB.
4031 ** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
4032 ** [prepared statement] S to have an SQL value of NULL, but to also be
4033 ** associated with the pointer P of type T. ^D is either a NULL pointer or
4034 ** a pointer to a destructor function for P. ^SQLite will invoke the
4035 ** destructor D with a single argument of P when it is finished using
4036 ** P. The T parameter should be a static string, preferably a string
4037 ** literal. The sqlite3_bind_pointer() routine is part of the
4038 ** [pointer passing interface] added for SQLite 3.20.0.
4040 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
4041 ** for the [prepared statement] or with a prepared statement for which
4042 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
4043 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
4044 ** routine is passed a [prepared statement] that has been finalized, the
4045 ** result is undefined and probably harmful.
4047 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
4048 ** ^Unbound parameters are interpreted as NULL.
4050 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
4051 ** [error code] if anything goes wrong.
4052 ** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
4053 ** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
4054 ** [SQLITE_MAX_LENGTH].
4055 ** ^[SQLITE_RANGE] is returned if the parameter
4056 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
4058 ** See also: [sqlite3_bind_parameter_count()],
4059 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
4061 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
4062 SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
4064 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
4065 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
4066 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
4067 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
4068 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
4069 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
4070 SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
4071 void(*)(void*), unsigned char encoding);
4072 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
4073 SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
4074 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
4075 SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
4078 ** CAPI3REF: Number Of SQL Parameters
4079 ** METHOD: sqlite3_stmt
4081 ** ^This routine can be used to find the number of [SQL parameters]
4082 ** in a [prepared statement]. SQL parameters are tokens of the
4083 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
4084 ** placeholders for values that are [sqlite3_bind_blob | bound]
4085 ** to the parameters at a later time.
4087 ** ^(This routine actually returns the index of the largest (rightmost)
4088 ** parameter. For all forms except ?NNN, this will correspond to the
4089 ** number of unique parameters. If parameters of the ?NNN form are used,
4090 ** there may be gaps in the list.)^
4092 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4093 ** [sqlite3_bind_parameter_name()], and
4094 ** [sqlite3_bind_parameter_index()].
4096 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
4099 ** CAPI3REF: Name Of A Host Parameter
4100 ** METHOD: sqlite3_stmt
4102 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
4103 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
4104 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
4105 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
4107 ** In other words, the initial ":" or "$" or "@" or "?"
4108 ** is included as part of the name.)^
4109 ** ^Parameters of the form "?" without a following integer have no name
4110 ** and are referred to as "nameless" or "anonymous parameters".
4112 ** ^The first host parameter has an index of 1, not 0.
4114 ** ^If the value N is out of range or if the N-th parameter is
4115 ** nameless, then NULL is returned. ^The returned string is
4116 ** always in UTF-8 encoding even if the named parameter was
4117 ** originally specified as UTF-16 in [sqlite3_prepare16()],
4118 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4120 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4121 ** [sqlite3_bind_parameter_count()], and
4122 ** [sqlite3_bind_parameter_index()].
4124 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
4127 ** CAPI3REF: Index Of A Parameter With A Given Name
4128 ** METHOD: sqlite3_stmt
4130 ** ^Return the index of an SQL parameter given its name. ^The
4131 ** index value returned is suitable for use as the second
4132 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
4133 ** is returned if no matching parameter is found. ^The parameter
4134 ** name must be given in UTF-8 even if the original statement
4135 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
4136 ** [sqlite3_prepare16_v3()].
4138 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4139 ** [sqlite3_bind_parameter_count()], and
4140 ** [sqlite3_bind_parameter_name()].
4142 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
4145 ** CAPI3REF: Reset All Bindings On A Prepared Statement
4146 ** METHOD: sqlite3_stmt
4148 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
4149 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
4150 ** ^Use this routine to reset all host parameters to NULL.
4152 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
4155 ** CAPI3REF: Number Of Columns In A Result Set
4156 ** METHOD: sqlite3_stmt
4158 ** ^Return the number of columns in the result set returned by the
4159 ** [prepared statement]. ^If this routine returns 0, that means the
4160 ** [prepared statement] returns no data (for example an [UPDATE]).
4161 ** ^However, just because this routine returns a positive number does not
4162 ** mean that one or more rows of data will be returned. ^A SELECT statement
4163 ** will always have a positive sqlite3_column_count() but depending on the
4164 ** WHERE clause constraints and the table content, it might return no rows.
4166 ** See also: [sqlite3_data_count()]
4168 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
4171 ** CAPI3REF: Column Names In A Result Set
4172 ** METHOD: sqlite3_stmt
4174 ** ^These routines return the name assigned to a particular column
4175 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
4176 ** interface returns a pointer to a zero-terminated UTF-8 string
4177 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
4178 ** UTF-16 string. ^The first parameter is the [prepared statement]
4179 ** that implements the [SELECT] statement. ^The second parameter is the
4180 ** column number. ^The leftmost column is number 0.
4182 ** ^The returned string pointer is valid until either the [prepared statement]
4183 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
4184 ** reprepared by the first call to [sqlite3_step()] for a particular run
4185 ** or until the next call to
4186 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
4188 ** ^If sqlite3_malloc() fails during the processing of either routine
4189 ** (for example during a conversion from UTF-8 to UTF-16) then a
4190 ** NULL pointer is returned.
4192 ** ^The name of a result column is the value of the "AS" clause for
4193 ** that column, if there is an AS clause. If there is no AS clause
4194 ** then the name of the column is unspecified and may change from
4195 ** one release of SQLite to the next.
4197 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
4198 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
4201 ** CAPI3REF: Source Of Data In A Query Result
4202 ** METHOD: sqlite3_stmt
4204 ** ^These routines provide a means to determine the database, table, and
4205 ** table column that is the origin of a particular result column in
4206 ** [SELECT] statement.
4207 ** ^The name of the database or table or column can be returned as
4208 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
4209 ** the database name, the _table_ routines return the table name, and
4210 ** the origin_ routines return the column name.
4211 ** ^The returned string is valid until the [prepared statement] is destroyed
4212 ** using [sqlite3_finalize()] or until the statement is automatically
4213 ** reprepared by the first call to [sqlite3_step()] for a particular run
4214 ** or until the same information is requested
4215 ** again in a different encoding.
4217 ** ^The names returned are the original un-aliased names of the
4218 ** database, table, and column.
4220 ** ^The first argument to these interfaces is a [prepared statement].
4221 ** ^These functions return information about the Nth result column returned by
4222 ** the statement, where N is the second function argument.
4223 ** ^The left-most column is column 0 for these routines.
4225 ** ^If the Nth column returned by the statement is an expression or
4226 ** subquery and is not a column value, then all of these functions return
4227 ** NULL. ^These routine might also return NULL if a memory allocation error
4228 ** occurs. ^Otherwise, they return the name of the attached database, table,
4229 ** or column that query result column was extracted from.
4231 ** ^As with all other SQLite APIs, those whose names end with "16" return
4232 ** UTF-16 encoded strings and the other functions return UTF-8.
4234 ** ^These APIs are only available if the library was compiled with the
4235 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
4237 ** If two or more threads call one or more of these routines against the same
4238 ** prepared statement and column at the same time then the results are
4241 ** If two or more threads call one or more
4242 ** [sqlite3_column_database_name | column metadata interfaces]
4243 ** for the same [prepared statement] and result column
4244 ** at the same time then the results are undefined.
4246 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
4247 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
4248 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
4249 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
4250 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
4251 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
4254 ** CAPI3REF: Declared Datatype Of A Query Result
4255 ** METHOD: sqlite3_stmt
4257 ** ^(The first parameter is a [prepared statement].
4258 ** If this statement is a [SELECT] statement and the Nth column of the
4259 ** returned result set of that [SELECT] is a table column (not an
4260 ** expression or subquery) then the declared type of the table
4261 ** column is returned.)^ ^If the Nth column of the result set is an
4262 ** expression or subquery, then a NULL pointer is returned.
4263 ** ^The returned string is always UTF-8 encoded.
4265 ** ^(For example, given the database schema:
4267 ** CREATE TABLE t1(c1 VARIANT);
4269 ** and the following statement to be compiled:
4271 ** SELECT c1 + 1, c1 FROM t1;
4273 ** this routine would return the string "VARIANT" for the second result
4274 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
4276 ** ^SQLite uses dynamic run-time typing. ^So just because a column
4277 ** is declared to contain a particular type does not mean that the
4278 ** data stored in that column is of the declared type. SQLite is
4279 ** strongly typed, but the typing is dynamic not static. ^Type
4280 ** is associated with individual values, not with the containers
4281 ** used to hold those values.
4283 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
4284 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
4287 ** CAPI3REF: Evaluate An SQL Statement
4288 ** METHOD: sqlite3_stmt
4290 ** After a [prepared statement] has been prepared using any of
4291 ** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
4292 ** or [sqlite3_prepare16_v3()] or one of the legacy
4293 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
4294 ** must be called one or more times to evaluate the statement.
4296 ** The details of the behavior of the sqlite3_step() interface depend
4297 ** on whether the statement was prepared using the newer "vX" interfaces
4298 ** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
4299 ** [sqlite3_prepare16_v2()] or the older legacy
4300 ** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
4301 ** new "vX" interface is recommended for new applications but the legacy
4302 ** interface will continue to be supported.
4304 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
4305 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
4306 ** ^With the "v2" interface, any of the other [result codes] or
4307 ** [extended result codes] might be returned as well.
4309 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
4310 ** database locks it needs to do its job. ^If the statement is a [COMMIT]
4311 ** or occurs outside of an explicit transaction, then you can retry the
4312 ** statement. If the statement is not a [COMMIT] and occurs within an
4313 ** explicit transaction then you should rollback the transaction before
4316 ** ^[SQLITE_DONE] means that the statement has finished executing
4317 ** successfully. sqlite3_step() should not be called again on this virtual
4318 ** machine without first calling [sqlite3_reset()] to reset the virtual
4319 ** machine back to its initial state.
4321 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
4322 ** is returned each time a new row of data is ready for processing by the
4323 ** caller. The values may be accessed using the [column access functions].
4324 ** sqlite3_step() is called again to retrieve the next row of data.
4326 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
4327 ** violation) has occurred. sqlite3_step() should not be called again on
4328 ** the VM. More information may be found by calling [sqlite3_errmsg()].
4329 ** ^With the legacy interface, a more specific error code (for example,
4330 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
4331 ** can be obtained by calling [sqlite3_reset()] on the
4332 ** [prepared statement]. ^In the "v2" interface,
4333 ** the more specific error code is returned directly by sqlite3_step().
4335 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
4336 ** Perhaps it was called on a [prepared statement] that has
4337 ** already been [sqlite3_finalize | finalized] or on one that had
4338 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
4339 ** be the case that the same database connection is being used by two or
4340 ** more threads at the same moment in time.
4342 ** For all versions of SQLite up to and including 3.6.23.1, a call to
4343 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
4344 ** other than [SQLITE_ROW] before any subsequent invocation of
4345 ** sqlite3_step(). Failure to reset the prepared statement using
4346 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
4347 ** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1],
4348 ** sqlite3_step() began
4349 ** calling [sqlite3_reset()] automatically in this circumstance rather
4350 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
4351 ** break because any application that ever receives an SQLITE_MISUSE error
4352 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
4353 ** can be used to restore the legacy behavior.
4355 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
4356 ** API always returns a generic error code, [SQLITE_ERROR], following any
4357 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
4358 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
4359 ** specific [error codes] that better describes the error.
4360 ** We admit that this is a goofy design. The problem has been fixed
4361 ** with the "v2" interface. If you prepare all of your SQL statements
4362 ** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
4363 ** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
4364 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
4365 ** then the more specific [error codes] are returned directly
4366 ** by sqlite3_step(). The use of the "vX" interfaces is recommended.
4368 SQLITE_API int sqlite3_step(sqlite3_stmt*);
4371 ** CAPI3REF: Number of columns in a result set
4372 ** METHOD: sqlite3_stmt
4374 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
4375 ** current row of the result set of [prepared statement] P.
4376 ** ^If prepared statement P does not have results ready to return
4377 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
4378 ** interfaces) then sqlite3_data_count(P) returns 0.
4379 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
4380 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
4381 ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
4382 ** will return non-zero if previous call to [sqlite3_step](P) returned
4383 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
4384 ** where it always returns zero since each step of that multi-step
4385 ** pragma returns 0 columns of data.
4387 ** See also: [sqlite3_column_count()]
4389 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
4392 ** CAPI3REF: Fundamental Datatypes
4393 ** KEYWORDS: SQLITE_TEXT
4395 ** ^(Every value in SQLite has one of five fundamental datatypes:
4398 ** <li> 64-bit signed integer
4399 ** <li> 64-bit IEEE floating point number
4405 ** These constants are codes for each of those types.
4407 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
4408 ** for a completely different meaning. Software that links against both
4409 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
4412 #define SQLITE_INTEGER 1
4413 #define SQLITE_FLOAT 2
4414 #define SQLITE_BLOB 4
4415 #define SQLITE_NULL 5
4419 # define SQLITE_TEXT 3
4421 #define SQLITE3_TEXT 3
4424 ** CAPI3REF: Result Values From A Query
4425 ** KEYWORDS: {column access functions}
4426 ** METHOD: sqlite3_stmt
4429 ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
4430 ** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result
4431 ** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result
4432 ** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result
4433 ** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result
4434 ** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result
4435 ** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result
4436 ** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an
4437 ** [sqlite3_value|unprotected sqlite3_value] object.
4438 ** <tr><td> <td> <td>
4439 ** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB
4440 ** or a UTF-8 TEXT result in bytes
4441 ** <tr><td><b>sqlite3_column_bytes16 </b>
4442 ** <td>→ <td>Size of UTF-16
4444 ** <tr><td><b>sqlite3_column_type</b><td>→<td>Default
4445 ** datatype of the result
4446 ** </table></blockquote>
4450 ** ^These routines return information about a single column of the current
4451 ** result row of a query. ^In every case the first argument is a pointer
4452 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
4453 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
4454 ** and the second argument is the index of the column for which information
4455 ** should be returned. ^The leftmost column of the result set has the index 0.
4456 ** ^The number of columns in the result can be determined using
4457 ** [sqlite3_column_count()].
4459 ** If the SQL statement does not currently point to a valid row, or if the
4460 ** column index is out of range, the result is undefined.
4461 ** These routines may only be called when the most recent call to
4462 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
4463 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
4464 ** If any of these routines are called after [sqlite3_reset()] or
4465 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
4466 ** something other than [SQLITE_ROW], the results are undefined.
4467 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
4468 ** are called from a different thread while any of these routines
4469 ** are pending, then the results are undefined.
4471 ** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
4472 ** each return the value of a result column in a specific data format. If
4473 ** the result column is not initially in the requested format (for example,
4474 ** if the query returns an integer but the sqlite3_column_text() interface
4475 ** is used to extract the value) then an automatic type conversion is performed.
4477 ** ^The sqlite3_column_type() routine returns the
4478 ** [SQLITE_INTEGER | datatype code] for the initial data type
4479 ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
4480 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
4481 ** The return value of sqlite3_column_type() can be used to decide which
4482 ** of the first six interface should be used to extract the column value.
4483 ** The value returned by sqlite3_column_type() is only meaningful if no
4484 ** automatic type conversions have occurred for the value in question.
4485 ** After a type conversion, the result of calling sqlite3_column_type()
4486 ** is undefined, though harmless. Future
4487 ** versions of SQLite may change the behavior of sqlite3_column_type()
4488 ** following a type conversion.
4490 ** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
4491 ** or sqlite3_column_bytes16() interfaces can be used to determine the size
4492 ** of that BLOB or string.
4494 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
4495 ** routine returns the number of bytes in that BLOB or string.
4496 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
4497 ** the string to UTF-8 and then returns the number of bytes.
4498 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
4499 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
4500 ** the number of bytes in that string.
4501 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
4503 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
4504 ** routine returns the number of bytes in that BLOB or string.
4505 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
4506 ** the string to UTF-16 and then returns the number of bytes.
4507 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
4508 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
4509 ** the number of bytes in that string.
4510 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
4512 ** ^The values returned by [sqlite3_column_bytes()] and
4513 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
4514 ** of the string. ^For clarity: the values returned by
4515 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
4516 ** bytes in the string, not the number of characters.
4518 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
4519 ** even empty strings, are always zero-terminated. ^The return
4520 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
4522 ** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
4523 ** [unprotected sqlite3_value] object. In a multithreaded environment,
4524 ** an unprotected sqlite3_value object may only be used safely with
4525 ** [sqlite3_bind_value()] and [sqlite3_result_value()].
4526 ** If the [unprotected sqlite3_value] object returned by
4527 ** [sqlite3_column_value()] is used in any other way, including calls
4528 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
4529 ** or [sqlite3_value_bytes()], the behavior is not threadsafe.
4530 ** Hence, the sqlite3_column_value() interface
4531 ** is normally only useful within the implementation of
4532 ** [application-defined SQL functions] or [virtual tables], not within
4533 ** top-level application code.
4535 ** The these routines may attempt to convert the datatype of the result.
4536 ** ^For example, if the internal representation is FLOAT and a text result
4537 ** is requested, [sqlite3_snprintf()] is used internally to perform the
4538 ** conversion automatically. ^(The following table details the conversions
4539 ** that are applied:
4542 ** <table border="1">
4543 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
4545 ** <tr><td> NULL <td> INTEGER <td> Result is 0
4546 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
4547 ** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer
4548 ** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer
4549 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
4550 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
4551 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
4552 ** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER
4553 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
4554 ** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB
4555 ** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER
4556 ** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL
4557 ** <tr><td> TEXT <td> BLOB <td> No change
4558 ** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER
4559 ** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL
4560 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
4564 ** Note that when type conversions occur, pointers returned by prior
4565 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
4566 ** sqlite3_column_text16() may be invalidated.
4567 ** Type conversions and pointer invalidations might occur
4568 ** in the following cases:
4571 ** <li> The initial content is a BLOB and sqlite3_column_text() or
4572 ** sqlite3_column_text16() is called. A zero-terminator might
4573 ** need to be added to the string.</li>
4574 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
4575 ** sqlite3_column_text16() is called. The content must be converted
4577 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
4578 ** sqlite3_column_text() is called. The content must be converted
4582 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
4583 ** not invalidate a prior pointer, though of course the content of the buffer
4584 ** that the prior pointer references will have been modified. Other kinds
4585 ** of conversion are done in place when it is possible, but sometimes they
4586 ** are not possible and in those cases prior pointers are invalidated.
4588 ** The safest policy is to invoke these routines
4589 ** in one of the following ways:
4592 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
4593 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
4594 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
4597 ** In other words, you should call sqlite3_column_text(),
4598 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
4599 ** into the desired format, then invoke sqlite3_column_bytes() or
4600 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
4601 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
4602 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
4603 ** with calls to sqlite3_column_bytes().
4605 ** ^The pointers returned are valid until a type conversion occurs as
4606 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
4607 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
4608 ** and BLOBs is freed automatically. Do not pass the pointers returned
4609 ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
4610 ** [sqlite3_free()].
4612 ** As long as the input parameters are correct, these routines will only
4613 ** fail if an out-of-memory error occurs during a format conversion.
4614 ** Only the following subset of interfaces are subject to out-of-memory
4618 ** <li> sqlite3_column_blob()
4619 ** <li> sqlite3_column_text()
4620 ** <li> sqlite3_column_text16()
4621 ** <li> sqlite3_column_bytes()
4622 ** <li> sqlite3_column_bytes16()
4625 ** If an out-of-memory error occurs, then the return value from these
4626 ** routines is the same as if the column had contained an SQL NULL value.
4627 ** Valid SQL NULL returns can be distinguished from out-of-memory errors
4628 ** by invoking the [sqlite3_errcode()] immediately after the suspect
4629 ** return value is obtained and before any
4630 ** other SQLite interface is called on the same [database connection].
4632 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
4633 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
4634 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
4635 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
4636 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
4637 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
4638 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
4639 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
4640 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
4641 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
4644 ** CAPI3REF: Destroy A Prepared Statement Object
4645 ** DESTRUCTOR: sqlite3_stmt
4647 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4648 ** ^If the most recent evaluation of the statement encountered no errors
4649 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
4650 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
4651 ** sqlite3_finalize(S) returns the appropriate [error code] or
4652 ** [extended error code].
4654 ** ^The sqlite3_finalize(S) routine can be called at any point during
4655 ** the life cycle of [prepared statement] S:
4656 ** before statement S is ever evaluated, after
4657 ** one or more calls to [sqlite3_reset()], or after any call
4658 ** to [sqlite3_step()] regardless of whether or not the statement has
4659 ** completed execution.
4661 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4663 ** The application must finalize every [prepared statement] in order to avoid
4664 ** resource leaks. It is a grievous error for the application to try to use
4665 ** a prepared statement after it has been finalized. Any use of a prepared
4666 ** statement after it has been finalized can result in undefined and
4667 ** undesirable behavior such as segfaults and heap corruption.
4669 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
4672 ** CAPI3REF: Reset A Prepared Statement Object
4673 ** METHOD: sqlite3_stmt
4675 ** The sqlite3_reset() function is called to reset a [prepared statement]
4676 ** object back to its initial state, ready to be re-executed.
4677 ** ^Any SQL statement variables that had values bound to them using
4678 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4679 ** Use [sqlite3_clear_bindings()] to reset the bindings.
4681 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4682 ** back to the beginning of its program.
4684 ** ^If the most recent call to [sqlite3_step(S)] for the
4685 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4686 ** or if [sqlite3_step(S)] has never before been called on S,
4687 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
4689 ** ^If the most recent call to [sqlite3_step(S)] for the
4690 ** [prepared statement] S indicated an error, then
4691 ** [sqlite3_reset(S)] returns an appropriate [error code].
4693 ** ^The [sqlite3_reset(S)] interface does not change the values
4694 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4696 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
4699 ** CAPI3REF: Create Or Redefine SQL Functions
4700 ** KEYWORDS: {function creation routines}
4701 ** KEYWORDS: {application-defined SQL function}
4702 ** KEYWORDS: {application-defined SQL functions}
4705 ** ^These functions (collectively known as "function creation routines")
4706 ** are used to add SQL functions or aggregates or to redefine the behavior
4707 ** of existing SQL functions or aggregates. The only differences between
4708 ** the three "sqlite3_create_function*" routines are the text encoding
4709 ** expected for the second parameter (the name of the function being
4710 ** created) and the presence or absence of a destructor callback for
4711 ** the application data pointer. Function sqlite3_create_window_function()
4712 ** is similar, but allows the user to supply the extra callback functions
4713 ** needed by [aggregate window functions].
4715 ** ^The first parameter is the [database connection] to which the SQL
4716 ** function is to be added. ^If an application uses more than one database
4717 ** connection then application-defined SQL functions must be added
4718 ** to each database connection separately.
4720 ** ^The second parameter is the name of the SQL function to be created or
4721 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
4722 ** representation, exclusive of the zero-terminator. ^Note that the name
4723 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4724 ** ^Any attempt to create a function with a longer name
4725 ** will result in [SQLITE_MISUSE] being returned.
4727 ** ^The third parameter (nArg)
4728 ** is the number of arguments that the SQL function or
4729 ** aggregate takes. ^If this parameter is -1, then the SQL function or
4730 ** aggregate may take any number of arguments between 0 and the limit
4731 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
4732 ** parameter is less than -1 or greater than 127 then the behavior is
4735 ** ^The fourth parameter, eTextRep, specifies what
4736 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4737 ** its parameters. The application should set this parameter to
4738 ** [SQLITE_UTF16LE] if the function implementation invokes
4739 ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4740 ** implementation invokes [sqlite3_value_text16be()] on an input, or
4741 ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4742 ** otherwise. ^The same SQL function may be registered multiple times using
4743 ** different preferred text encodings, with different implementations for
4745 ** ^When multiple implementations of the same function are available, SQLite
4746 ** will pick the one that involves the least amount of data conversion.
4748 ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4749 ** to signal that the function will always return the same result given
4750 ** the same inputs within a single SQL statement. Most SQL functions are
4751 ** deterministic. The built-in [random()] SQL function is an example of a
4752 ** function that is not deterministic. The SQLite query planner is able to
4753 ** perform additional optimizations on deterministic functions, so use
4754 ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4756 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
4757 ** function can gain access to this pointer using [sqlite3_user_data()].)^
4759 ** ^The sixth, seventh and eighth parameters passed to the three
4760 ** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
4761 ** pointers to C-language functions that implement the SQL function or
4762 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4763 ** callback only; NULL pointers must be passed as the xStep and xFinal
4764 ** parameters. ^An aggregate SQL function requires an implementation of xStep
4765 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4766 ** SQL function or aggregate, pass NULL pointers for all three function
4769 ** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
4770 ** and xInverse) passed to sqlite3_create_window_function are pointers to
4771 ** C-language callbacks that implement the new function. xStep and xFinal
4772 ** must both be non-NULL. xValue and xInverse may either both be NULL, in
4773 ** which case a regular aggregate function is created, or must both be
4774 ** non-NULL, in which case the new function may be used as either an aggregate
4775 ** or aggregate window function. More details regarding the implementation
4776 ** of aggregate window functions are
4777 ** [user-defined window functions|available here].
4779 ** ^(If the final parameter to sqlite3_create_function_v2() or
4780 ** sqlite3_create_window_function() is not NULL, then it is destructor for
4781 ** the application data pointer. The destructor is invoked when the function
4782 ** is deleted, either by being overloaded or when the database connection
4783 ** closes.)^ ^The destructor is also invoked if the call to
4784 ** sqlite3_create_function_v2() fails. ^When the destructor callback is
4785 ** invoked, it is passed a single argument which is a copy of the application
4786 ** data pointer which was the fifth parameter to sqlite3_create_function_v2().
4788 ** ^It is permitted to register multiple implementations of the same
4789 ** functions with the same name but with either differing numbers of
4790 ** arguments or differing preferred text encodings. ^SQLite will use
4791 ** the implementation that most closely matches the way in which the
4792 ** SQL function is used. ^A function implementation with a non-negative
4793 ** nArg parameter is a better match than a function implementation with
4794 ** a negative nArg. ^A function where the preferred text encoding
4795 ** matches the database encoding is a better
4796 ** match than a function where the encoding is different.
4797 ** ^A function where the encoding difference is between UTF16le and UTF16be
4798 ** is a closer match than a function where the encoding difference is
4799 ** between UTF8 and UTF16.
4801 ** ^Built-in functions may be overloaded by new application-defined functions.
4803 ** ^An application-defined function is permitted to call other
4804 ** SQLite interfaces. However, such calls must not
4805 ** close the database connection nor finalize or reset the prepared
4806 ** statement in which the function is running.
4808 SQLITE_API int sqlite3_create_function(
4810 const char *zFunctionName,
4814 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4815 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4816 void (*xFinal)(sqlite3_context*)
4818 SQLITE_API int sqlite3_create_function16(
4820 const void *zFunctionName,
4824 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4825 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4826 void (*xFinal)(sqlite3_context*)
4828 SQLITE_API int sqlite3_create_function_v2(
4830 const char *zFunctionName,
4834 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4835 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4836 void (*xFinal)(sqlite3_context*),
4837 void(*xDestroy)(void*)
4839 SQLITE_API int sqlite3_create_window_function(
4841 const char *zFunctionName,
4845 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4846 void (*xFinal)(sqlite3_context*),
4847 void (*xValue)(sqlite3_context*),
4848 void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
4849 void(*xDestroy)(void*)
4853 ** CAPI3REF: Text Encodings
4855 ** These constant define integer codes that represent the various
4856 ** text encodings supported by SQLite.
4858 #define SQLITE_UTF8 1 /* IMP: R-37514-35566 */
4859 #define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */
4860 #define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */
4861 #define SQLITE_UTF16 4 /* Use native byte order */
4862 #define SQLITE_ANY 5 /* Deprecated */
4863 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
4866 ** CAPI3REF: Function Flags
4868 ** These constants may be ORed together with the
4869 ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4870 ** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4871 ** [sqlite3_create_function_v2()].
4873 #define SQLITE_DETERMINISTIC 0x800
4876 ** CAPI3REF: Deprecated Functions
4879 ** These functions are [deprecated]. In order to maintain
4880 ** backwards compatibility with older code, these functions continue
4881 ** to be supported. However, new applications should avoid
4882 ** the use of these functions. To encourage programmers to avoid
4883 ** these functions, we will not explain what they do.
4885 #ifndef SQLITE_OMIT_DEPRECATED
4886 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
4887 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
4888 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4889 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
4890 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
4891 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4892 void*,sqlite3_int64);
4896 ** CAPI3REF: Obtaining SQL Values
4897 ** METHOD: sqlite3_value
4900 ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
4901 ** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value
4902 ** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value
4903 ** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value
4904 ** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value
4905 ** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value
4906 ** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value
4907 ** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in
4908 ** the native byteorder
4909 ** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value
4910 ** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value
4911 ** <tr><td> <td> <td>
4912 ** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB
4913 ** or a UTF-8 TEXT in bytes
4914 ** <tr><td><b>sqlite3_value_bytes16 </b>
4915 ** <td>→ <td>Size of UTF-16
4917 ** <tr><td><b>sqlite3_value_type</b><td>→<td>Default
4918 ** datatype of the value
4919 ** <tr><td><b>sqlite3_value_numeric_type </b>
4920 ** <td>→ <td>Best numeric datatype of the value
4921 ** <tr><td><b>sqlite3_value_nochange </b>
4922 ** <td>→ <td>True if the column is unchanged in an UPDATE
4923 ** against a virtual table.
4924 ** </table></blockquote>
4928 ** These routines extract type, size, and content information from
4929 ** [protected sqlite3_value] objects. Protected sqlite3_value objects
4930 ** are used to pass parameter information into implementation of
4931 ** [application-defined SQL functions] and [virtual tables].
4933 ** These routines work only with [protected sqlite3_value] objects.
4934 ** Any attempt to use these routines on an [unprotected sqlite3_value]
4935 ** is not threadsafe.
4937 ** ^These routines work just like the corresponding [column access functions]
4938 ** except that these routines take a single [protected sqlite3_value] object
4939 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4941 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4942 ** in the native byte-order of the host machine. ^The
4943 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4944 ** extract UTF-16 strings as big-endian and little-endian respectively.
4946 ** ^If [sqlite3_value] object V was initialized
4947 ** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
4948 ** and if X and Y are strings that compare equal according to strcmp(X,Y),
4949 ** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise,
4950 ** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
4951 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
4953 ** ^(The sqlite3_value_type(V) interface returns the
4954 ** [SQLITE_INTEGER | datatype code] for the initial datatype of the
4955 ** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
4956 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
4957 ** Other interfaces might change the datatype for an sqlite3_value object.
4958 ** For example, if the datatype is initially SQLITE_INTEGER and
4959 ** sqlite3_value_text(V) is called to extract a text value for that
4960 ** integer, then subsequent calls to sqlite3_value_type(V) might return
4961 ** SQLITE_TEXT. Whether or not a persistent internal datatype conversion
4962 ** occurs is undefined and may change from one release of SQLite to the next.
4964 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
4965 ** numeric affinity to the value. This means that an attempt is
4966 ** made to convert the value to an integer or floating point. If
4967 ** such a conversion is possible without loss of information (in other
4968 ** words, if the value is a string that looks like a number)
4969 ** then the conversion is performed. Otherwise no conversion occurs.
4970 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4972 ** ^Within the [xUpdate] method of a [virtual table], the
4973 ** sqlite3_value_nochange(X) interface returns true if and only if
4974 ** the column corresponding to X is unchanged by the UPDATE operation
4975 ** that the xUpdate method call was invoked to implement and if
4976 ** and the prior [xColumn] method call that was invoked to extracted
4977 ** the value for that column returned without setting a result (probably
4978 ** because it queried [sqlite3_vtab_nochange()] and found that the column
4979 ** was unchanging). ^Within an [xUpdate] method, any value for which
4980 ** sqlite3_value_nochange(X) is true will in all other respects appear
4981 ** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other
4982 ** than within an [xUpdate] method call for an UPDATE statement, then
4983 ** the return value is arbitrary and meaningless.
4985 ** Please pay particular attention to the fact that the pointer returned
4986 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4987 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4988 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4989 ** or [sqlite3_value_text16()].
4991 ** These routines must be called from the same thread as
4992 ** the SQL function that supplied the [sqlite3_value*] parameters.
4994 ** As long as the input parameter is correct, these routines can only
4995 ** fail if an out-of-memory error occurs during a format conversion.
4996 ** Only the following subset of interfaces are subject to out-of-memory
5000 ** <li> sqlite3_value_blob()
5001 ** <li> sqlite3_value_text()
5002 ** <li> sqlite3_value_text16()
5003 ** <li> sqlite3_value_text16le()
5004 ** <li> sqlite3_value_text16be()
5005 ** <li> sqlite3_value_bytes()
5006 ** <li> sqlite3_value_bytes16()
5009 ** If an out-of-memory error occurs, then the return value from these
5010 ** routines is the same as if the column had contained an SQL NULL value.
5011 ** Valid SQL NULL returns can be distinguished from out-of-memory errors
5012 ** by invoking the [sqlite3_errcode()] immediately after the suspect
5013 ** return value is obtained and before any
5014 ** other SQLite interface is called on the same [database connection].
5016 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
5017 SQLITE_API double sqlite3_value_double(sqlite3_value*);
5018 SQLITE_API int sqlite3_value_int(sqlite3_value*);
5019 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
5020 SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
5021 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
5022 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
5023 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
5024 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
5025 SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
5026 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
5027 SQLITE_API int sqlite3_value_type(sqlite3_value*);
5028 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
5029 SQLITE_API int sqlite3_value_nochange(sqlite3_value*);
5032 ** CAPI3REF: Finding The Subtype Of SQL Values
5033 ** METHOD: sqlite3_value
5035 ** The sqlite3_value_subtype(V) function returns the subtype for
5036 ** an [application-defined SQL function] argument V. The subtype
5037 ** information can be used to pass a limited amount of context from
5038 ** one SQL function to another. Use the [sqlite3_result_subtype()]
5039 ** routine to set the subtype for the return value of an SQL function.
5041 SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
5044 ** CAPI3REF: Copy And Free SQL Values
5045 ** METHOD: sqlite3_value
5047 ** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
5048 ** object D and returns a pointer to that copy. ^The [sqlite3_value] returned
5049 ** is a [protected sqlite3_value] object even if the input is not.
5050 ** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
5051 ** memory allocation fails.
5053 ** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
5054 ** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer
5055 ** then sqlite3_value_free(V) is a harmless no-op.
5057 SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
5058 SQLITE_API void sqlite3_value_free(sqlite3_value*);
5061 ** CAPI3REF: Obtain Aggregate Function Context
5062 ** METHOD: sqlite3_context
5064 ** Implementations of aggregate SQL functions use this
5065 ** routine to allocate memory for storing their state.
5067 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
5068 ** for a particular aggregate function, SQLite
5069 ** allocates N of memory, zeroes out that memory, and returns a pointer
5070 ** to the new memory. ^On second and subsequent calls to
5071 ** sqlite3_aggregate_context() for the same aggregate function instance,
5072 ** the same buffer is returned. Sqlite3_aggregate_context() is normally
5073 ** called once for each invocation of the xStep callback and then one
5074 ** last time when the xFinal callback is invoked. ^(When no rows match
5075 ** an aggregate query, the xStep() callback of the aggregate function
5076 ** implementation is never called and xFinal() is called exactly once.
5077 ** In those cases, sqlite3_aggregate_context() might be called for the
5078 ** first time from within xFinal().)^
5080 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
5081 ** when first called if N is less than or equal to zero or if a memory
5082 ** allocate error occurs.
5084 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
5085 ** determined by the N parameter on first successful call. Changing the
5086 ** value of N in subsequent call to sqlite3_aggregate_context() within
5087 ** the same aggregate function instance will not resize the memory
5088 ** allocation.)^ Within the xFinal callback, it is customary to set
5089 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
5090 ** pointless memory allocations occur.
5092 ** ^SQLite automatically frees the memory allocated by
5093 ** sqlite3_aggregate_context() when the aggregate query concludes.
5095 ** The first parameter must be a copy of the
5096 ** [sqlite3_context | SQL function context] that is the first parameter
5097 ** to the xStep or xFinal callback routine that implements the aggregate
5100 ** This routine must be called from the same thread in which
5101 ** the aggregate SQL function is running.
5103 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
5106 ** CAPI3REF: User Data For Functions
5107 ** METHOD: sqlite3_context
5109 ** ^The sqlite3_user_data() interface returns a copy of
5110 ** the pointer that was the pUserData parameter (the 5th parameter)
5111 ** of the [sqlite3_create_function()]
5112 ** and [sqlite3_create_function16()] routines that originally
5113 ** registered the application defined function.
5115 ** This routine must be called from the same thread in which
5116 ** the application-defined function is running.
5118 SQLITE_API void *sqlite3_user_data(sqlite3_context*);
5121 ** CAPI3REF: Database Connection For Functions
5122 ** METHOD: sqlite3_context
5124 ** ^The sqlite3_context_db_handle() interface returns a copy of
5125 ** the pointer to the [database connection] (the 1st parameter)
5126 ** of the [sqlite3_create_function()]
5127 ** and [sqlite3_create_function16()] routines that originally
5128 ** registered the application defined function.
5130 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
5133 ** CAPI3REF: Function Auxiliary Data
5134 ** METHOD: sqlite3_context
5136 ** These functions may be used by (non-aggregate) SQL functions to
5137 ** associate metadata with argument values. If the same value is passed to
5138 ** multiple invocations of the same SQL function during query execution, under
5139 ** some circumstances the associated metadata may be preserved. An example
5140 ** of where this might be useful is in a regular-expression matching
5141 ** function. The compiled version of the regular expression can be stored as
5142 ** metadata associated with the pattern string.
5143 ** Then as long as the pattern string remains the same,
5144 ** the compiled regular expression can be reused on multiple
5145 ** invocations of the same function.
5147 ** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata
5148 ** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
5149 ** value to the application-defined function. ^N is zero for the left-most
5150 ** function argument. ^If there is no metadata
5151 ** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
5152 ** returns a NULL pointer.
5154 ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
5155 ** argument of the application-defined function. ^Subsequent
5156 ** calls to sqlite3_get_auxdata(C,N) return P from the most recent
5157 ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
5158 ** NULL if the metadata has been discarded.
5159 ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
5160 ** SQLite will invoke the destructor function X with parameter P exactly
5161 ** once, when the metadata is discarded.
5162 ** SQLite is free to discard the metadata at any time, including: <ul>
5163 ** <li> ^(when the corresponding function parameter changes)^, or
5164 ** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
5165 ** SQL statement)^, or
5166 ** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
5168 ** <li> ^(during the original sqlite3_set_auxdata() call when a memory
5169 ** allocation error occurs.)^ </ul>
5171 ** Note the last bullet in particular. The destructor X in
5172 ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
5173 ** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
5174 ** should be called near the end of the function implementation and the
5175 ** function implementation should not make any use of P after
5176 ** sqlite3_set_auxdata() has been called.
5178 ** ^(In practice, metadata is preserved between function calls for
5179 ** function parameters that are compile-time constants, including literal
5180 ** values and [parameters] and expressions composed from the same.)^
5182 ** The value of the N parameter to these interfaces should be non-negative.
5183 ** Future enhancements may make use of negative N values to define new
5184 ** kinds of function caching behavior.
5186 ** These routines must be called from the same thread in which
5187 ** the SQL function is running.
5189 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
5190 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
5194 ** CAPI3REF: Constants Defining Special Destructor Behavior
5196 ** These are special values for the destructor that is passed in as the
5197 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
5198 ** argument is SQLITE_STATIC, it means that the content pointer is constant
5199 ** and will never change. It does not need to be destroyed. ^The
5200 ** SQLITE_TRANSIENT value means that the content will likely change in
5201 ** the near future and that SQLite should make its own private copy of
5202 ** the content before returning.
5204 ** The typedef is necessary to work around problems in certain
5207 typedef void (*sqlite3_destructor_type)(void*);
5208 #define SQLITE_STATIC ((sqlite3_destructor_type)0)
5209 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
5212 ** CAPI3REF: Setting The Result Of An SQL Function
5213 ** METHOD: sqlite3_context
5215 ** These routines are used by the xFunc or xFinal callbacks that
5216 ** implement SQL functions and aggregates. See
5217 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
5218 ** for additional information.
5220 ** These functions work very much like the [parameter binding] family of
5221 ** functions used to bind values to host parameters in prepared statements.
5222 ** Refer to the [SQL parameter] documentation for additional information.
5224 ** ^The sqlite3_result_blob() interface sets the result from
5225 ** an application-defined function to be the BLOB whose content is pointed
5226 ** to by the second parameter and which is N bytes long where N is the
5229 ** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
5230 ** interfaces set the result of the application-defined function to be
5231 ** a BLOB containing all zero bytes and N bytes in size.
5233 ** ^The sqlite3_result_double() interface sets the result from
5234 ** an application-defined function to be a floating point value specified
5235 ** by its 2nd argument.
5237 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
5238 ** cause the implemented SQL function to throw an exception.
5239 ** ^SQLite uses the string pointed to by the
5240 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
5241 ** as the text of an error message. ^SQLite interprets the error
5242 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
5243 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
5244 ** byte order. ^If the third parameter to sqlite3_result_error()
5245 ** or sqlite3_result_error16() is negative then SQLite takes as the error
5246 ** message all text up through the first zero character.
5247 ** ^If the third parameter to sqlite3_result_error() or
5248 ** sqlite3_result_error16() is non-negative then SQLite takes that many
5249 ** bytes (not characters) from the 2nd parameter as the error message.
5250 ** ^The sqlite3_result_error() and sqlite3_result_error16()
5251 ** routines make a private copy of the error message text before
5252 ** they return. Hence, the calling function can deallocate or
5253 ** modify the text after they return without harm.
5254 ** ^The sqlite3_result_error_code() function changes the error code
5255 ** returned by SQLite as a result of an error in a function. ^By default,
5256 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
5257 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
5259 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
5260 ** error indicating that a string or BLOB is too long to represent.
5262 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
5263 ** error indicating that a memory allocation failed.
5265 ** ^The sqlite3_result_int() interface sets the return value
5266 ** of the application-defined function to be the 32-bit signed integer
5267 ** value given in the 2nd argument.
5268 ** ^The sqlite3_result_int64() interface sets the return value
5269 ** of the application-defined function to be the 64-bit signed integer
5270 ** value given in the 2nd argument.
5272 ** ^The sqlite3_result_null() interface sets the return value
5273 ** of the application-defined function to be NULL.
5275 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
5276 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
5277 ** set the return value of the application-defined function to be
5278 ** a text string which is represented as UTF-8, UTF-16 native byte order,
5279 ** UTF-16 little endian, or UTF-16 big endian, respectively.
5280 ** ^The sqlite3_result_text64() interface sets the return value of an
5281 ** application-defined function to be a text string in an encoding
5282 ** specified by the fifth (and last) parameter, which must be one
5283 ** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
5284 ** ^SQLite takes the text result from the application from
5285 ** the 2nd parameter of the sqlite3_result_text* interfaces.
5286 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5287 ** is negative, then SQLite takes result text from the 2nd parameter
5288 ** through the first zero character.
5289 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5290 ** is non-negative, then as many bytes (not characters) of the text
5291 ** pointed to by the 2nd parameter are taken as the application-defined
5292 ** function result. If the 3rd parameter is non-negative, then it
5293 ** must be the byte offset into the string where the NUL terminator would
5294 ** appear if the string where NUL terminated. If any NUL characters occur
5295 ** in the string at a byte offset that is less than the value of the 3rd
5296 ** parameter, then the resulting string will contain embedded NULs and the
5297 ** result of expressions operating on strings with embedded NULs is undefined.
5298 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
5299 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
5300 ** function as the destructor on the text or BLOB result when it has
5301 ** finished using that result.
5302 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
5303 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
5304 ** assumes that the text or BLOB result is in constant space and does not
5305 ** copy the content of the parameter nor call a destructor on the content
5306 ** when it has finished using that result.
5307 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
5308 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
5309 ** then SQLite makes a copy of the result into space obtained
5310 ** from [sqlite3_malloc()] before it returns.
5312 ** ^The sqlite3_result_value() interface sets the result of
5313 ** the application-defined function to be a copy of the
5314 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
5315 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
5316 ** so that the [sqlite3_value] specified in the parameter may change or
5317 ** be deallocated after sqlite3_result_value() returns without harm.
5318 ** ^A [protected sqlite3_value] object may always be used where an
5319 ** [unprotected sqlite3_value] object is required, so either
5320 ** kind of [sqlite3_value] object can be used with this interface.
5322 ** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
5323 ** SQL NULL value, just like [sqlite3_result_null(C)], except that it
5324 ** also associates the host-language pointer P or type T with that
5325 ** NULL value such that the pointer can be retrieved within an
5326 ** [application-defined SQL function] using [sqlite3_value_pointer()].
5327 ** ^If the D parameter is not NULL, then it is a pointer to a destructor
5328 ** for the P parameter. ^SQLite invokes D with P as its only argument
5329 ** when SQLite is finished with P. The T parameter should be a static
5330 ** string and preferably a string literal. The sqlite3_result_pointer()
5331 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5333 ** If these routines are called from within the different thread
5334 ** than the one containing the application-defined function that received
5335 ** the [sqlite3_context] pointer, the results are undefined.
5337 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
5338 SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
5339 sqlite3_uint64,void(*)(void*));
5340 SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
5341 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
5342 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
5343 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
5344 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
5345 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
5346 SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
5347 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
5348 SQLITE_API void sqlite3_result_null(sqlite3_context*);
5349 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
5350 SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
5351 void(*)(void*), unsigned char encoding);
5352 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
5353 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
5354 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
5355 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
5356 SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
5357 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
5358 SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
5362 ** CAPI3REF: Setting The Subtype Of An SQL Function
5363 ** METHOD: sqlite3_context
5365 ** The sqlite3_result_subtype(C,T) function causes the subtype of
5366 ** the result from the [application-defined SQL function] with
5367 ** [sqlite3_context] C to be the value T. Only the lower 8 bits
5368 ** of the subtype T are preserved in current versions of SQLite;
5369 ** higher order bits are discarded.
5370 ** The number of subtype bytes preserved by SQLite might increase
5371 ** in future releases of SQLite.
5373 SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
5376 ** CAPI3REF: Define New Collating Sequences
5379 ** ^These functions add, remove, or modify a [collation] associated
5380 ** with the [database connection] specified as the first argument.
5382 ** ^The name of the collation is a UTF-8 string
5383 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
5384 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
5385 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
5386 ** considered to be the same name.
5388 ** ^(The third argument (eTextRep) must be one of the constants:
5390 ** <li> [SQLITE_UTF8],
5391 ** <li> [SQLITE_UTF16LE],
5392 ** <li> [SQLITE_UTF16BE],
5393 ** <li> [SQLITE_UTF16], or
5394 ** <li> [SQLITE_UTF16_ALIGNED].
5396 ** ^The eTextRep argument determines the encoding of strings passed
5397 ** to the collating function callback, xCallback.
5398 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
5399 ** force strings to be UTF16 with native byte order.
5400 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
5401 ** on an even byte address.
5403 ** ^The fourth argument, pArg, is an application data pointer that is passed
5404 ** through as the first argument to the collating function callback.
5406 ** ^The fifth argument, xCallback, is a pointer to the collating function.
5407 ** ^Multiple collating functions can be registered using the same name but
5408 ** with different eTextRep parameters and SQLite will use whichever
5409 ** function requires the least amount of data transformation.
5410 ** ^If the xCallback argument is NULL then the collating function is
5411 ** deleted. ^When all collating functions having the same name are deleted,
5412 ** that collation is no longer usable.
5414 ** ^The collating function callback is invoked with a copy of the pArg
5415 ** application data pointer and with two strings in the encoding specified
5416 ** by the eTextRep argument. The collating function must return an
5417 ** integer that is negative, zero, or positive
5418 ** if the first string is less than, equal to, or greater than the second,
5419 ** respectively. A collating function must always return the same answer
5420 ** given the same inputs. If two or more collating functions are registered
5421 ** to the same collation name (using different eTextRep values) then all
5422 ** must give an equivalent answer when invoked with equivalent strings.
5423 ** The collating function must obey the following properties for all
5424 ** strings A, B, and C:
5427 ** <li> If A==B then B==A.
5428 ** <li> If A==B and B==C then A==C.
5429 ** <li> If A<B THEN B>A.
5430 ** <li> If A<B and B<C then A<C.
5433 ** If a collating function fails any of the above constraints and that
5434 ** collating function is registered and used, then the behavior of SQLite
5437 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
5438 ** with the addition that the xDestroy callback is invoked on pArg when
5439 ** the collating function is deleted.
5440 ** ^Collating functions are deleted when they are overridden by later
5441 ** calls to the collation creation functions or when the
5442 ** [database connection] is closed using [sqlite3_close()].
5444 ** ^The xDestroy callback is <u>not</u> called if the
5445 ** sqlite3_create_collation_v2() function fails. Applications that invoke
5446 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
5447 ** check the return code and dispose of the application data pointer
5448 ** themselves rather than expecting SQLite to deal with it for them.
5449 ** This is different from every other SQLite interface. The inconsistency
5450 ** is unfortunate but cannot be changed without breaking backwards
5453 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
5455 SQLITE_API int sqlite3_create_collation(
5460 int(*xCompare)(void*,int,const void*,int,const void*)
5462 SQLITE_API int sqlite3_create_collation_v2(
5467 int(*xCompare)(void*,int,const void*,int,const void*),
5468 void(*xDestroy)(void*)
5470 SQLITE_API int sqlite3_create_collation16(
5475 int(*xCompare)(void*,int,const void*,int,const void*)
5479 ** CAPI3REF: Collation Needed Callbacks
5482 ** ^To avoid having to register all collation sequences before a database
5483 ** can be used, a single callback function may be registered with the
5484 ** [database connection] to be invoked whenever an undefined collation
5485 ** sequence is required.
5487 ** ^If the function is registered using the sqlite3_collation_needed() API,
5488 ** then it is passed the names of undefined collation sequences as strings
5489 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
5490 ** the names are passed as UTF-16 in machine native byte order.
5491 ** ^A call to either function replaces the existing collation-needed callback.
5493 ** ^(When the callback is invoked, the first argument passed is a copy
5494 ** of the second argument to sqlite3_collation_needed() or
5495 ** sqlite3_collation_needed16(). The second argument is the database
5496 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
5497 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
5498 ** sequence function required. The fourth parameter is the name of the
5499 ** required collation sequence.)^
5501 ** The callback function should register the desired collation using
5502 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
5503 ** [sqlite3_create_collation_v2()].
5505 SQLITE_API int sqlite3_collation_needed(
5508 void(*)(void*,sqlite3*,int eTextRep,const char*)
5510 SQLITE_API int sqlite3_collation_needed16(
5513 void(*)(void*,sqlite3*,int eTextRep,const void*)
5516 #ifdef SQLITE_HAS_CODEC
5518 ** Specify the key for an encrypted database. This routine should be
5519 ** called right after sqlite3_open().
5521 ** The code to implement this API is not available in the public release
5524 SQLITE_API int sqlite3_key(
5525 sqlite3 *db, /* Database to be rekeyed */
5526 const void *pKey, int nKey /* The key */
5528 SQLITE_API int sqlite3_key_v2(
5529 sqlite3 *db, /* Database to be rekeyed */
5530 const char *zDbName, /* Name of the database */
5531 const void *pKey, int nKey /* The key */
5535 ** Change the key on an open database. If the current database is not
5536 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
5537 ** database is decrypted.
5539 ** The code to implement this API is not available in the public release
5542 SQLITE_API int sqlite3_rekey(
5543 sqlite3 *db, /* Database to be rekeyed */
5544 const void *pKey, int nKey /* The new key */
5546 SQLITE_API int sqlite3_rekey_v2(
5547 sqlite3 *db, /* Database to be rekeyed */
5548 const char *zDbName, /* Name of the database */
5549 const void *pKey, int nKey /* The new key */
5553 ** Specify the activation key for a SEE database. Unless
5554 ** activated, none of the SEE routines will work.
5556 SQLITE_API void sqlite3_activate_see(
5557 const char *zPassPhrase /* Activation phrase */
5561 #ifdef SQLITE_ENABLE_CEROD
5563 ** Specify the activation key for a CEROD database. Unless
5564 ** activated, none of the CEROD routines will work.
5566 SQLITE_API void sqlite3_activate_cerod(
5567 const char *zPassPhrase /* Activation phrase */
5572 ** CAPI3REF: Suspend Execution For A Short Time
5574 ** The sqlite3_sleep() function causes the current thread to suspend execution
5575 ** for at least a number of milliseconds specified in its parameter.
5577 ** If the operating system does not support sleep requests with
5578 ** millisecond time resolution, then the time will be rounded up to
5579 ** the nearest second. The number of milliseconds of sleep actually
5580 ** requested from the operating system is returned.
5582 ** ^SQLite implements this interface by calling the xSleep()
5583 ** method of the default [sqlite3_vfs] object. If the xSleep() method
5584 ** of the default VFS is not implemented correctly, or not implemented at
5585 ** all, then the behavior of sqlite3_sleep() may deviate from the description
5586 ** in the previous paragraphs.
5588 SQLITE_API int sqlite3_sleep(int);
5591 ** CAPI3REF: Name Of The Folder Holding Temporary Files
5593 ** ^(If this global variable is made to point to a string which is
5594 ** the name of a folder (a.k.a. directory), then all temporary files
5595 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
5596 ** will be placed in that directory.)^ ^If this variable
5597 ** is a NULL pointer, then SQLite performs a search for an appropriate
5598 ** temporary file directory.
5600 ** Applications are strongly discouraged from using this global variable.
5601 ** It is required to set a temporary folder on Windows Runtime (WinRT).
5602 ** But for all other platforms, it is highly recommended that applications
5603 ** neither read nor write this variable. This global variable is a relic
5604 ** that exists for backwards compatibility of legacy applications and should
5605 ** be avoided in new projects.
5607 ** It is not safe to read or modify this variable in more than one
5608 ** thread at a time. It is not safe to read or modify this variable
5609 ** if a [database connection] is being used at the same time in a separate
5611 ** It is intended that this variable be set once
5612 ** as part of process initialization and before any SQLite interface
5613 ** routines have been called and that this variable remain unchanged
5616 ** ^The [temp_store_directory pragma] may modify this variable and cause
5617 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
5618 ** the [temp_store_directory pragma] always assumes that any string
5619 ** that this variable points to is held in memory obtained from
5620 ** [sqlite3_malloc] and the pragma may attempt to free that memory
5621 ** using [sqlite3_free].
5622 ** Hence, if this variable is modified directly, either it should be
5623 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
5624 ** or else the use of the [temp_store_directory pragma] should be avoided.
5625 ** Except when requested by the [temp_store_directory pragma], SQLite
5626 ** does not free the memory that sqlite3_temp_directory points to. If
5627 ** the application wants that memory to be freed, it must do
5628 ** so itself, taking care to only do so after all [database connection]
5629 ** objects have been destroyed.
5631 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
5632 ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
5633 ** features that require the use of temporary files may fail. Here is an
5634 ** example of how to do this using C++ with the Windows Runtime:
5636 ** <blockquote><pre>
5637 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
5638 ** TemporaryFolder->Path->Data();
5639 ** char zPathBuf[MAX_PATH + 1];
5640 ** memset(zPathBuf, 0, sizeof(zPathBuf));
5641 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
5642 ** NULL, NULL);
5643 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
5644 ** </pre></blockquote>
5646 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
5649 ** CAPI3REF: Name Of The Folder Holding Database Files
5651 ** ^(If this global variable is made to point to a string which is
5652 ** the name of a folder (a.k.a. directory), then all database files
5653 ** specified with a relative pathname and created or accessed by
5654 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
5655 ** to be relative to that directory.)^ ^If this variable is a NULL
5656 ** pointer, then SQLite assumes that all database files specified
5657 ** with a relative pathname are relative to the current directory
5658 ** for the process. Only the windows VFS makes use of this global
5659 ** variable; it is ignored by the unix VFS.
5661 ** Changing the value of this variable while a database connection is
5662 ** open can result in a corrupt database.
5664 ** It is not safe to read or modify this variable in more than one
5665 ** thread at a time. It is not safe to read or modify this variable
5666 ** if a [database connection] is being used at the same time in a separate
5668 ** It is intended that this variable be set once
5669 ** as part of process initialization and before any SQLite interface
5670 ** routines have been called and that this variable remain unchanged
5673 ** ^The [data_store_directory pragma] may modify this variable and cause
5674 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
5675 ** the [data_store_directory pragma] always assumes that any string
5676 ** that this variable points to is held in memory obtained from
5677 ** [sqlite3_malloc] and the pragma may attempt to free that memory
5678 ** using [sqlite3_free].
5679 ** Hence, if this variable is modified directly, either it should be
5680 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
5681 ** or else the use of the [data_store_directory pragma] should be avoided.
5683 SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
5686 ** CAPI3REF: Win32 Specific Interface
5688 ** These interfaces are available only on Windows. The
5689 ** [sqlite3_win32_set_directory] interface is used to set the value associated
5690 ** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
5691 ** zValue, depending on the value of the type parameter. The zValue parameter
5692 ** should be NULL to cause the previous value to be freed via [sqlite3_free];
5693 ** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
5694 ** prior to being used. The [sqlite3_win32_set_directory] interface returns
5695 ** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
5696 ** or [SQLITE_NOMEM] if memory could not be allocated. The value of the
5697 ** [sqlite3_data_directory] variable is intended to act as a replacement for
5698 ** the current directory on the sub-platforms of Win32 where that concept is
5699 ** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and
5700 ** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
5701 ** sqlite3_win32_set_directory interface except the string parameter must be
5702 ** UTF-8 or UTF-16, respectively.
5704 SQLITE_API int sqlite3_win32_set_directory(
5705 unsigned long type, /* Identifier for directory being set or reset */
5706 void *zValue /* New value for directory being set or reset */
5708 SQLITE_API int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
5709 SQLITE_API int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
5712 ** CAPI3REF: Win32 Directory Types
5714 ** These macros are only available on Windows. They define the allowed values
5715 ** for the type argument to the [sqlite3_win32_set_directory] interface.
5717 #define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1
5718 #define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2
5721 ** CAPI3REF: Test For Auto-Commit Mode
5722 ** KEYWORDS: {autocommit mode}
5725 ** ^The sqlite3_get_autocommit() interface returns non-zero or
5726 ** zero if the given database connection is or is not in autocommit mode,
5727 ** respectively. ^Autocommit mode is on by default.
5728 ** ^Autocommit mode is disabled by a [BEGIN] statement.
5729 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
5731 ** If certain kinds of errors occur on a statement within a multi-statement
5732 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
5733 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
5734 ** transaction might be rolled back automatically. The only way to
5735 ** find out whether SQLite automatically rolled back the transaction after
5736 ** an error is to use this function.
5738 ** If another thread changes the autocommit status of the database
5739 ** connection while this routine is running, then the return value
5742 SQLITE_API int sqlite3_get_autocommit(sqlite3*);
5745 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
5746 ** METHOD: sqlite3_stmt
5748 ** ^The sqlite3_db_handle interface returns the [database connection] handle
5749 ** to which a [prepared statement] belongs. ^The [database connection]
5750 ** returned by sqlite3_db_handle is the same [database connection]
5751 ** that was the first argument
5752 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
5753 ** create the statement in the first place.
5755 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
5758 ** CAPI3REF: Return The Filename For A Database Connection
5761 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
5762 ** associated with database N of connection D. ^The main database file
5763 ** has the name "main". If there is no attached database N on the database
5764 ** connection D, or if database N is a temporary or in-memory database, then
5765 ** a NULL pointer is returned.
5767 ** ^The filename returned by this function is the output of the
5768 ** xFullPathname method of the [VFS]. ^In other words, the filename
5769 ** will be an absolute pathname, even if the filename used
5770 ** to open the database originally was a URI or relative pathname.
5772 SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
5775 ** CAPI3REF: Determine if a database is read-only
5778 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
5779 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
5780 ** the name of a database on connection D.
5782 SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
5785 ** CAPI3REF: Find the next prepared statement
5788 ** ^This interface returns a pointer to the next [prepared statement] after
5789 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
5790 ** then this interface returns a pointer to the first prepared statement
5791 ** associated with the database connection pDb. ^If no prepared statement
5792 ** satisfies the conditions of this routine, it returns NULL.
5794 ** The [database connection] pointer D in a call to
5795 ** [sqlite3_next_stmt(D,S)] must refer to an open database
5796 ** connection and in particular must not be a NULL pointer.
5798 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
5801 ** CAPI3REF: Commit And Rollback Notification Callbacks
5804 ** ^The sqlite3_commit_hook() interface registers a callback
5805 ** function to be invoked whenever a transaction is [COMMIT | committed].
5806 ** ^Any callback set by a previous call to sqlite3_commit_hook()
5807 ** for the same database connection is overridden.
5808 ** ^The sqlite3_rollback_hook() interface registers a callback
5809 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
5810 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
5811 ** for the same database connection is overridden.
5812 ** ^The pArg argument is passed through to the callback.
5813 ** ^If the callback on a commit hook function returns non-zero,
5814 ** then the commit is converted into a rollback.
5816 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
5817 ** return the P argument from the previous call of the same function
5818 ** on the same [database connection] D, or NULL for
5819 ** the first call for each function on D.
5821 ** The commit and rollback hook callbacks are not reentrant.
5822 ** The callback implementation must not do anything that will modify
5823 ** the database connection that invoked the callback. Any actions
5824 ** to modify the database connection must be deferred until after the
5825 ** completion of the [sqlite3_step()] call that triggered the commit
5826 ** or rollback hook in the first place.
5827 ** Note that running any other SQL statements, including SELECT statements,
5828 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
5829 ** the database connections for the meaning of "modify" in this paragraph.
5831 ** ^Registering a NULL function disables the callback.
5833 ** ^When the commit hook callback routine returns zero, the [COMMIT]
5834 ** operation is allowed to continue normally. ^If the commit hook
5835 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
5836 ** ^The rollback hook is invoked on a rollback that results from a commit
5837 ** hook returning non-zero, just as it would be with any other rollback.
5839 ** ^For the purposes of this API, a transaction is said to have been
5840 ** rolled back if an explicit "ROLLBACK" statement is executed, or
5841 ** an error or constraint causes an implicit rollback to occur.
5842 ** ^The rollback callback is not invoked if a transaction is
5843 ** automatically rolled back because the database connection is closed.
5845 ** See also the [sqlite3_update_hook()] interface.
5847 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
5848 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
5851 ** CAPI3REF: Data Change Notification Callbacks
5854 ** ^The sqlite3_update_hook() interface registers a callback function
5855 ** with the [database connection] identified by the first argument
5856 ** to be invoked whenever a row is updated, inserted or deleted in
5858 ** ^Any callback set by a previous call to this function
5859 ** for the same database connection is overridden.
5861 ** ^The second argument is a pointer to the function to invoke when a
5862 ** row is updated, inserted or deleted in a rowid table.
5863 ** ^The first argument to the callback is a copy of the third argument
5864 ** to sqlite3_update_hook().
5865 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
5866 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
5868 ** ^The third and fourth arguments to the callback contain pointers to the
5869 ** database and table name containing the affected row.
5870 ** ^The final callback parameter is the [rowid] of the row.
5871 ** ^In the case of an update, this is the [rowid] after the update takes place.
5873 ** ^(The update hook is not invoked when internal system tables are
5874 ** modified (i.e. sqlite_master and sqlite_sequence).)^
5875 ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
5877 ** ^In the current implementation, the update hook
5878 ** is not invoked when conflicting rows are deleted because of an
5879 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
5880 ** invoked when rows are deleted using the [truncate optimization].
5881 ** The exceptions defined in this paragraph might change in a future
5882 ** release of SQLite.
5884 ** The update hook implementation must not do anything that will modify
5885 ** the database connection that invoked the update hook. Any actions
5886 ** to modify the database connection must be deferred until after the
5887 ** completion of the [sqlite3_step()] call that triggered the update hook.
5888 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
5889 ** database connections for the meaning of "modify" in this paragraph.
5891 ** ^The sqlite3_update_hook(D,C,P) function
5892 ** returns the P argument from the previous call
5893 ** on the same [database connection] D, or NULL for
5894 ** the first call on D.
5896 ** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
5897 ** and [sqlite3_preupdate_hook()] interfaces.
5899 SQLITE_API void *sqlite3_update_hook(
5901 void(*)(void *,int ,char const *,char const *,sqlite3_int64),
5906 ** CAPI3REF: Enable Or Disable Shared Pager Cache
5908 ** ^(This routine enables or disables the sharing of the database cache
5909 ** and schema data structures between [database connection | connections]
5910 ** to the same database. Sharing is enabled if the argument is true
5911 ** and disabled if the argument is false.)^
5913 ** ^Cache sharing is enabled and disabled for an entire process.
5914 ** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
5915 ** In prior versions of SQLite,
5916 ** sharing was enabled or disabled for each thread separately.
5918 ** ^(The cache sharing mode set by this interface effects all subsequent
5919 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
5920 ** Existing database connections continue use the sharing mode
5921 ** that was in effect at the time they were opened.)^
5923 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
5924 ** successfully. An [error code] is returned otherwise.)^
5926 ** ^Shared cache is disabled by default. But this might change in
5927 ** future releases of SQLite. Applications that care about shared
5928 ** cache setting should set it explicitly.
5930 ** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
5931 ** and will always return SQLITE_MISUSE. On those systems,
5932 ** shared cache mode should be enabled per-database connection via
5933 ** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
5935 ** This interface is threadsafe on processors where writing a
5936 ** 32-bit integer is atomic.
5938 ** See Also: [SQLite Shared-Cache Mode]
5940 SQLITE_API int sqlite3_enable_shared_cache(int);
5943 ** CAPI3REF: Attempt To Free Heap Memory
5945 ** ^The sqlite3_release_memory() interface attempts to free N bytes
5946 ** of heap memory by deallocating non-essential memory allocations
5947 ** held by the database library. Memory used to cache database
5948 ** pages to improve performance is an example of non-essential memory.
5949 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
5950 ** which might be more or less than the amount requested.
5951 ** ^The sqlite3_release_memory() routine is a no-op returning zero
5952 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5954 ** See also: [sqlite3_db_release_memory()]
5956 SQLITE_API int sqlite3_release_memory(int);
5959 ** CAPI3REF: Free Memory Used By A Database Connection
5962 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
5963 ** memory as possible from database connection D. Unlike the
5964 ** [sqlite3_release_memory()] interface, this interface is in effect even
5965 ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
5968 ** See also: [sqlite3_release_memory()]
5970 SQLITE_API int sqlite3_db_release_memory(sqlite3*);
5973 ** CAPI3REF: Impose A Limit On Heap Size
5975 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
5976 ** soft limit on the amount of heap memory that may be allocated by SQLite.
5977 ** ^SQLite strives to keep heap memory utilization below the soft heap
5978 ** limit by reducing the number of pages held in the page cache
5979 ** as heap memory usages approaches the limit.
5980 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
5981 ** below the limit, it will exceed the limit rather than generate
5982 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
5983 ** is advisory only.
5985 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
5986 ** the soft heap limit prior to the call, or negative in the case of an
5987 ** error. ^If the argument N is negative
5988 ** then no change is made to the soft heap limit. Hence, the current
5989 ** size of the soft heap limit can be determined by invoking
5990 ** sqlite3_soft_heap_limit64() with a negative argument.
5992 ** ^If the argument N is zero then the soft heap limit is disabled.
5994 ** ^(The soft heap limit is not enforced in the current implementation
5995 ** if one or more of following conditions are true:
5998 ** <li> The soft heap limit is set to zero.
5999 ** <li> Memory accounting is disabled using a combination of the
6000 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
6001 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
6002 ** <li> An alternative page cache implementation is specified using
6003 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
6004 ** <li> The page cache allocates from its own memory pool supplied
6005 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
6009 ** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]),
6010 ** the soft heap limit is enforced
6011 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
6012 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
6013 ** the soft heap limit is enforced on every memory allocation. Without
6014 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
6015 ** when memory is allocated by the page cache. Testing suggests that because
6016 ** the page cache is the predominate memory user in SQLite, most
6017 ** applications will achieve adequate soft heap limit enforcement without
6018 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
6020 ** The circumstances under which SQLite will enforce the soft heap limit may
6021 ** changes in future releases of SQLite.
6023 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
6026 ** CAPI3REF: Deprecated Soft Heap Limit Interface
6029 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
6030 ** interface. This routine is provided for historical compatibility
6031 ** only. All new applications should use the
6032 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
6034 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
6038 ** CAPI3REF: Extract Metadata About A Column Of A Table
6041 ** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
6042 ** information about column C of table T in database D
6043 ** on [database connection] X.)^ ^The sqlite3_table_column_metadata()
6044 ** interface returns SQLITE_OK and fills in the non-NULL pointers in
6045 ** the final five arguments with appropriate values if the specified
6046 ** column exists. ^The sqlite3_table_column_metadata() interface returns
6047 ** SQLITE_ERROR and if the specified column does not exist.
6048 ** ^If the column-name parameter to sqlite3_table_column_metadata() is a
6049 ** NULL pointer, then this routine simply checks for the existence of the
6050 ** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
6051 ** does not. If the table name parameter T in a call to
6052 ** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
6053 ** undefined behavior.
6055 ** ^The column is identified by the second, third and fourth parameters to
6056 ** this function. ^(The second parameter is either the name of the database
6057 ** (i.e. "main", "temp", or an attached database) containing the specified
6058 ** table or NULL.)^ ^If it is NULL, then all attached databases are searched
6059 ** for the table using the same algorithm used by the database engine to
6060 ** resolve unqualified table references.
6062 ** ^The third and fourth parameters to this function are the table and column
6063 ** name of the desired column, respectively.
6065 ** ^Metadata is returned by writing to the memory locations passed as the 5th
6066 ** and subsequent parameters to this function. ^Any of these arguments may be
6067 ** NULL, in which case the corresponding element of metadata is omitted.
6070 ** <table border="1">
6071 ** <tr><th> Parameter <th> Output<br>Type <th> Description
6073 ** <tr><td> 5th <td> const char* <td> Data type
6074 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
6075 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
6076 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
6077 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
6081 ** ^The memory pointed to by the character pointers returned for the
6082 ** declaration type and collation sequence is valid until the next
6083 ** call to any SQLite API function.
6085 ** ^If the specified table is actually a view, an [error code] is returned.
6087 ** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
6088 ** is not a [WITHOUT ROWID] table and an
6089 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
6090 ** parameters are set for the explicitly declared column. ^(If there is no
6091 ** [INTEGER PRIMARY KEY] column, then the outputs
6092 ** for the [rowid] are set as follows:
6095 ** data type: "INTEGER"
6096 ** collation sequence: "BINARY"
6099 ** auto increment: 0
6102 ** ^This function causes all database schemas to be read from disk and
6103 ** parsed, if that has not already been done, and returns an error if
6104 ** any errors are encountered while loading the schema.
6106 SQLITE_API int sqlite3_table_column_metadata(
6107 sqlite3 *db, /* Connection handle */
6108 const char *zDbName, /* Database name or NULL */
6109 const char *zTableName, /* Table name */
6110 const char *zColumnName, /* Column name */
6111 char const **pzDataType, /* OUTPUT: Declared data type */
6112 char const **pzCollSeq, /* OUTPUT: Collation sequence name */
6113 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
6114 int *pPrimaryKey, /* OUTPUT: True if column part of PK */
6115 int *pAutoinc /* OUTPUT: True if column is auto-increment */
6119 ** CAPI3REF: Load An Extension
6122 ** ^This interface loads an SQLite extension library from the named file.
6124 ** ^The sqlite3_load_extension() interface attempts to load an
6125 ** [SQLite extension] library contained in the file zFile. If
6126 ** the file cannot be loaded directly, attempts are made to load
6127 ** with various operating-system specific extensions added.
6128 ** So for example, if "samplelib" cannot be loaded, then names like
6129 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
6132 ** ^The entry point is zProc.
6133 ** ^(zProc may be 0, in which case SQLite will try to come up with an
6134 ** entry point name on its own. It first tries "sqlite3_extension_init".
6135 ** If that does not work, it constructs a name "sqlite3_X_init" where the
6136 ** X is consists of the lower-case equivalent of all ASCII alphabetic
6137 ** characters in the filename from the last "/" to the first following
6138 ** "." and omitting any initial "lib".)^
6139 ** ^The sqlite3_load_extension() interface returns
6140 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
6141 ** ^If an error occurs and pzErrMsg is not 0, then the
6142 ** [sqlite3_load_extension()] interface shall attempt to
6143 ** fill *pzErrMsg with error message text stored in memory
6144 ** obtained from [sqlite3_malloc()]. The calling function
6145 ** should free this memory by calling [sqlite3_free()].
6147 ** ^Extension loading must be enabled using
6148 ** [sqlite3_enable_load_extension()] or
6149 ** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
6150 ** prior to calling this API,
6151 ** otherwise an error will be returned.
6153 ** <b>Security warning:</b> It is recommended that the
6154 ** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
6155 ** interface. The use of the [sqlite3_enable_load_extension()] interface
6156 ** should be avoided. This will keep the SQL function [load_extension()]
6157 ** disabled and prevent SQL injections from giving attackers
6158 ** access to extension loading capabilities.
6160 ** See also the [load_extension() SQL function].
6162 SQLITE_API int sqlite3_load_extension(
6163 sqlite3 *db, /* Load the extension into this database connection */
6164 const char *zFile, /* Name of the shared library containing extension */
6165 const char *zProc, /* Entry point. Derived from zFile if 0 */
6166 char **pzErrMsg /* Put error message here if not 0 */
6170 ** CAPI3REF: Enable Or Disable Extension Loading
6173 ** ^So as not to open security holes in older applications that are
6174 ** unprepared to deal with [extension loading], and as a means of disabling
6175 ** [extension loading] while evaluating user-entered SQL, the following API
6176 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
6178 ** ^Extension loading is off by default.
6179 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
6180 ** to turn extension loading on and call it with onoff==0 to turn
6181 ** it back off again.
6183 ** ^This interface enables or disables both the C-API
6184 ** [sqlite3_load_extension()] and the SQL function [load_extension()].
6185 ** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
6186 ** to enable or disable only the C-API.)^
6188 ** <b>Security warning:</b> It is recommended that extension loading
6189 ** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
6190 ** rather than this interface, so the [load_extension()] SQL function
6191 ** remains disabled. This will prevent SQL injections from giving attackers
6192 ** access to extension loading capabilities.
6194 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
6197 ** CAPI3REF: Automatically Load Statically Linked Extensions
6199 ** ^This interface causes the xEntryPoint() function to be invoked for
6200 ** each new [database connection] that is created. The idea here is that
6201 ** xEntryPoint() is the entry point for a statically linked [SQLite extension]
6202 ** that is to be automatically loaded into all new database connections.
6204 ** ^(Even though the function prototype shows that xEntryPoint() takes
6205 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
6206 ** arguments and expects an integer result as if the signature of the
6207 ** entry point where as follows:
6209 ** <blockquote><pre>
6210 ** int xEntryPoint(
6211 ** sqlite3 *db,
6212 ** const char **pzErrMsg,
6213 ** const struct sqlite3_api_routines *pThunk
6215 ** </pre></blockquote>)^
6217 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
6218 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
6219 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
6220 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
6221 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
6222 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
6223 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
6225 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
6226 ** on the list of automatic extensions is a harmless no-op. ^No entry point
6227 ** will be called more than once for each database connection that is opened.
6229 ** See also: [sqlite3_reset_auto_extension()]
6230 ** and [sqlite3_cancel_auto_extension()]
6232 SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
6235 ** CAPI3REF: Cancel Automatic Extension Loading
6237 ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
6238 ** initialization routine X that was registered using a prior call to
6239 ** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)]
6240 ** routine returns 1 if initialization routine X was successfully
6241 ** unregistered and it returns 0 if X was not on the list of initialization
6244 SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
6247 ** CAPI3REF: Reset Automatic Extension Loading
6249 ** ^This interface disables all automatic extensions previously
6250 ** registered using [sqlite3_auto_extension()].
6252 SQLITE_API void sqlite3_reset_auto_extension(void);
6255 ** The interface to the virtual-table mechanism is currently considered
6256 ** to be experimental. The interface might change in incompatible ways.
6257 ** If this is a problem for you, do not use the interface at this time.
6259 ** When the virtual-table mechanism stabilizes, we will declare the
6260 ** interface fixed, support it indefinitely, and remove this comment.
6264 ** Structures used by the virtual table interface
6266 typedef struct sqlite3_vtab sqlite3_vtab;
6267 typedef struct sqlite3_index_info sqlite3_index_info;
6268 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
6269 typedef struct sqlite3_module sqlite3_module;
6272 ** CAPI3REF: Virtual Table Object
6273 ** KEYWORDS: sqlite3_module {virtual table module}
6275 ** This structure, sometimes called a "virtual table module",
6276 ** defines the implementation of a [virtual tables].
6277 ** This structure consists mostly of methods for the module.
6279 ** ^A virtual table module is created by filling in a persistent
6280 ** instance of this structure and passing a pointer to that instance
6281 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
6282 ** ^The registration remains valid until it is replaced by a different
6283 ** module or until the [database connection] closes. The content
6284 ** of this structure must not change while it is registered with
6285 ** any database connection.
6287 struct sqlite3_module {
6289 int (*xCreate)(sqlite3*, void *pAux,
6290 int argc, const char *const*argv,
6291 sqlite3_vtab **ppVTab, char**);
6292 int (*xConnect)(sqlite3*, void *pAux,
6293 int argc, const char *const*argv,
6294 sqlite3_vtab **ppVTab, char**);
6295 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
6296 int (*xDisconnect)(sqlite3_vtab *pVTab);
6297 int (*xDestroy)(sqlite3_vtab *pVTab);
6298 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
6299 int (*xClose)(sqlite3_vtab_cursor*);
6300 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
6301 int argc, sqlite3_value **argv);
6302 int (*xNext)(sqlite3_vtab_cursor*);
6303 int (*xEof)(sqlite3_vtab_cursor*);
6304 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
6305 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
6306 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
6307 int (*xBegin)(sqlite3_vtab *pVTab);
6308 int (*xSync)(sqlite3_vtab *pVTab);
6309 int (*xCommit)(sqlite3_vtab *pVTab);
6310 int (*xRollback)(sqlite3_vtab *pVTab);
6311 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
6312 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
6314 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
6315 /* The methods above are in version 1 of the sqlite_module object. Those
6316 ** below are for version 2 and greater. */
6317 int (*xSavepoint)(sqlite3_vtab *pVTab, int);
6318 int (*xRelease)(sqlite3_vtab *pVTab, int);
6319 int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
6320 /* The methods above are in versions 1 and 2 of the sqlite_module object.
6321 ** Those below are for version 3 and greater. */
6322 int (*xShadowName)(const char*);
6326 ** CAPI3REF: Virtual Table Indexing Information
6327 ** KEYWORDS: sqlite3_index_info
6329 ** The sqlite3_index_info structure and its substructures is used as part
6330 ** of the [virtual table] interface to
6331 ** pass information into and receive the reply from the [xBestIndex]
6332 ** method of a [virtual table module]. The fields under **Inputs** are the
6333 ** inputs to xBestIndex and are read-only. xBestIndex inserts its
6334 ** results into the **Outputs** fields.
6336 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
6338 ** <blockquote>column OP expr</blockquote>
6340 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is
6341 ** stored in aConstraint[].op using one of the
6342 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
6343 ** ^(The index of the column is stored in
6344 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
6345 ** expr on the right-hand side can be evaluated (and thus the constraint
6346 ** is usable) and false if it cannot.)^
6348 ** ^The optimizer automatically inverts terms of the form "expr OP column"
6349 ** and makes other simplifications to the WHERE clause in an attempt to
6350 ** get as many WHERE clause terms into the form shown above as possible.
6351 ** ^The aConstraint[] array only reports WHERE clause terms that are
6352 ** relevant to the particular virtual table being queried.
6354 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
6355 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
6357 ** The colUsed field indicates which columns of the virtual table may be
6358 ** required by the current scan. Virtual table columns are numbered from
6359 ** zero in the order in which they appear within the CREATE TABLE statement
6360 ** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
6361 ** the corresponding bit is set within the colUsed mask if the column may be
6362 ** required by SQLite. If the table has at least 64 columns and any column
6363 ** to the right of the first 63 is required, then bit 63 of colUsed is also
6364 ** set. In other words, column iCol may be required if the expression
6365 ** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
6368 ** The [xBestIndex] method must fill aConstraintUsage[] with information
6369 ** about what parameters to pass to xFilter. ^If argvIndex>0 then
6370 ** the right-hand side of the corresponding aConstraint[] is evaluated
6371 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
6372 ** is true, then the constraint is assumed to be fully handled by the
6373 ** virtual table and is not checked again by SQLite.)^
6375 ** ^The idxNum and idxPtr values are recorded and passed into the
6376 ** [xFilter] method.
6377 ** ^[sqlite3_free()] is used to free idxPtr if and only if
6378 ** needToFreeIdxPtr is true.
6380 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
6381 ** the correct order to satisfy the ORDER BY clause so that no separate
6382 ** sorting step is required.
6384 ** ^The estimatedCost value is an estimate of the cost of a particular
6385 ** strategy. A cost of N indicates that the cost of the strategy is similar
6386 ** to a linear scan of an SQLite table with N rows. A cost of log(N)
6387 ** indicates that the expense of the operation is similar to that of a
6388 ** binary search on a unique indexed field of an SQLite table with N rows.
6390 ** ^The estimatedRows value is an estimate of the number of rows that
6391 ** will be returned by the strategy.
6393 ** The xBestIndex method may optionally populate the idxFlags field with a
6394 ** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
6395 ** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
6396 ** assumes that the strategy may visit at most one row.
6398 ** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
6399 ** SQLite also assumes that if a call to the xUpdate() method is made as
6400 ** part of the same statement to delete or update a virtual table row and the
6401 ** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
6402 ** any database changes. In other words, if the xUpdate() returns
6403 ** SQLITE_CONSTRAINT, the database contents must be exactly as they were
6404 ** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
6405 ** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
6406 ** the xUpdate method are automatically rolled back by SQLite.
6408 ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
6409 ** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
6410 ** If a virtual table extension is
6411 ** used with an SQLite version earlier than 3.8.2, the results of attempting
6412 ** to read or write the estimatedRows field are undefined (but are likely
6413 ** to included crashing the application). The estimatedRows field should
6414 ** therefore only be used if [sqlite3_libversion_number()] returns a
6415 ** value greater than or equal to 3008002. Similarly, the idxFlags field
6416 ** was added for [version 3.9.0] ([dateof:3.9.0]).
6417 ** It may therefore only be used if
6418 ** sqlite3_libversion_number() returns a value greater than or equal to
6421 struct sqlite3_index_info {
6423 int nConstraint; /* Number of entries in aConstraint */
6424 struct sqlite3_index_constraint {
6425 int iColumn; /* Column constrained. -1 for ROWID */
6426 unsigned char op; /* Constraint operator */
6427 unsigned char usable; /* True if this constraint is usable */
6428 int iTermOffset; /* Used internally - xBestIndex should ignore */
6429 } *aConstraint; /* Table of WHERE clause constraints */
6430 int nOrderBy; /* Number of terms in the ORDER BY clause */
6431 struct sqlite3_index_orderby {
6432 int iColumn; /* Column number */
6433 unsigned char desc; /* True for DESC. False for ASC. */
6434 } *aOrderBy; /* The ORDER BY clause */
6436 struct sqlite3_index_constraint_usage {
6437 int argvIndex; /* if >0, constraint is part of argv to xFilter */
6438 unsigned char omit; /* Do not code a test for this constraint */
6439 } *aConstraintUsage;
6440 int idxNum; /* Number used to identify the index */
6441 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
6442 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
6443 int orderByConsumed; /* True if output is already ordered */
6444 double estimatedCost; /* Estimated cost of using this index */
6445 /* Fields below are only available in SQLite 3.8.2 and later */
6446 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */
6447 /* Fields below are only available in SQLite 3.9.0 and later */
6448 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */
6449 /* Fields below are only available in SQLite 3.10.0 and later */
6450 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */
6454 ** CAPI3REF: Virtual Table Scan Flags
6456 ** Virtual table implementations are allowed to set the
6457 ** [sqlite3_index_info].idxFlags field to some combination of
6460 #define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */
6463 ** CAPI3REF: Virtual Table Constraint Operator Codes
6465 ** These macros defined the allowed values for the
6466 ** [sqlite3_index_info].aConstraint[].op field. Each value represents
6467 ** an operator that is part of a constraint term in the wHERE clause of
6468 ** a query that uses a [virtual table].
6470 #define SQLITE_INDEX_CONSTRAINT_EQ 2
6471 #define SQLITE_INDEX_CONSTRAINT_GT 4
6472 #define SQLITE_INDEX_CONSTRAINT_LE 8
6473 #define SQLITE_INDEX_CONSTRAINT_LT 16
6474 #define SQLITE_INDEX_CONSTRAINT_GE 32
6475 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
6476 #define SQLITE_INDEX_CONSTRAINT_LIKE 65
6477 #define SQLITE_INDEX_CONSTRAINT_GLOB 66
6478 #define SQLITE_INDEX_CONSTRAINT_REGEXP 67
6479 #define SQLITE_INDEX_CONSTRAINT_NE 68
6480 #define SQLITE_INDEX_CONSTRAINT_ISNOT 69
6481 #define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70
6482 #define SQLITE_INDEX_CONSTRAINT_ISNULL 71
6483 #define SQLITE_INDEX_CONSTRAINT_IS 72
6484 #define SQLITE_INDEX_CONSTRAINT_FUNCTION 150
6487 ** CAPI3REF: Register A Virtual Table Implementation
6490 ** ^These routines are used to register a new [virtual table module] name.
6491 ** ^Module names must be registered before
6492 ** creating a new [virtual table] using the module and before using a
6493 ** preexisting [virtual table] for the module.
6495 ** ^The module name is registered on the [database connection] specified
6496 ** by the first parameter. ^The name of the module is given by the
6497 ** second parameter. ^The third parameter is a pointer to
6498 ** the implementation of the [virtual table module]. ^The fourth
6499 ** parameter is an arbitrary client data pointer that is passed through
6500 ** into the [xCreate] and [xConnect] methods of the virtual table module
6501 ** when a new virtual table is be being created or reinitialized.
6503 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
6504 ** is a pointer to a destructor for the pClientData. ^SQLite will
6505 ** invoke the destructor function (if it is not NULL) when SQLite
6506 ** no longer needs the pClientData pointer. ^The destructor will also
6507 ** be invoked if the call to sqlite3_create_module_v2() fails.
6508 ** ^The sqlite3_create_module()
6509 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
6512 SQLITE_API int sqlite3_create_module(
6513 sqlite3 *db, /* SQLite connection to register module with */
6514 const char *zName, /* Name of the module */
6515 const sqlite3_module *p, /* Methods for the module */
6516 void *pClientData /* Client data for xCreate/xConnect */
6518 SQLITE_API int sqlite3_create_module_v2(
6519 sqlite3 *db, /* SQLite connection to register module with */
6520 const char *zName, /* Name of the module */
6521 const sqlite3_module *p, /* Methods for the module */
6522 void *pClientData, /* Client data for xCreate/xConnect */
6523 void(*xDestroy)(void*) /* Module destructor function */
6527 ** CAPI3REF: Virtual Table Instance Object
6528 ** KEYWORDS: sqlite3_vtab
6530 ** Every [virtual table module] implementation uses a subclass
6531 ** of this object to describe a particular instance
6532 ** of the [virtual table]. Each subclass will
6533 ** be tailored to the specific needs of the module implementation.
6534 ** The purpose of this superclass is to define certain fields that are
6535 ** common to all module implementations.
6537 ** ^Virtual tables methods can set an error message by assigning a
6538 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
6539 ** take care that any prior string is freed by a call to [sqlite3_free()]
6540 ** prior to assigning a new string to zErrMsg. ^After the error message
6541 ** is delivered up to the client application, the string will be automatically
6542 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
6544 struct sqlite3_vtab {
6545 const sqlite3_module *pModule; /* The module for this virtual table */
6546 int nRef; /* Number of open cursors */
6547 char *zErrMsg; /* Error message from sqlite3_mprintf() */
6548 /* Virtual table implementations will typically add additional fields */
6552 ** CAPI3REF: Virtual Table Cursor Object
6553 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
6555 ** Every [virtual table module] implementation uses a subclass of the
6556 ** following structure to describe cursors that point into the
6557 ** [virtual table] and are used
6558 ** to loop through the virtual table. Cursors are created using the
6559 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
6560 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
6561 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
6562 ** of the module. Each module implementation will define
6563 ** the content of a cursor structure to suit its own needs.
6565 ** This superclass exists in order to define fields of the cursor that
6566 ** are common to all implementations.
6568 struct sqlite3_vtab_cursor {
6569 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
6570 /* Virtual table implementations will typically add additional fields */
6574 ** CAPI3REF: Declare The Schema Of A Virtual Table
6576 ** ^The [xCreate] and [xConnect] methods of a
6577 ** [virtual table module] call this interface
6578 ** to declare the format (the names and datatypes of the columns) of
6579 ** the virtual tables they implement.
6581 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
6584 ** CAPI3REF: Overload A Function For A Virtual Table
6587 ** ^(Virtual tables can provide alternative implementations of functions
6588 ** using the [xFindFunction] method of the [virtual table module].
6589 ** But global versions of those functions
6590 ** must exist in order to be overloaded.)^
6592 ** ^(This API makes sure a global version of a function with a particular
6593 ** name and number of parameters exists. If no such function exists
6594 ** before this API is called, a new function is created.)^ ^The implementation
6595 ** of the new function always causes an exception to be thrown. So
6596 ** the new function is not good for anything by itself. Its only
6597 ** purpose is to be a placeholder function that can be overloaded
6598 ** by a [virtual table].
6600 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
6603 ** The interface to the virtual-table mechanism defined above (back up
6604 ** to a comment remarkably similar to this one) is currently considered
6605 ** to be experimental. The interface might change in incompatible ways.
6606 ** If this is a problem for you, do not use the interface at this time.
6608 ** When the virtual-table mechanism stabilizes, we will declare the
6609 ** interface fixed, support it indefinitely, and remove this comment.
6613 ** CAPI3REF: A Handle To An Open BLOB
6614 ** KEYWORDS: {BLOB handle} {BLOB handles}
6616 ** An instance of this object represents an open BLOB on which
6617 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
6618 ** ^Objects of this type are created by [sqlite3_blob_open()]
6619 ** and destroyed by [sqlite3_blob_close()].
6620 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
6621 ** can be used to read or write small subsections of the BLOB.
6622 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
6624 typedef struct sqlite3_blob sqlite3_blob;
6627 ** CAPI3REF: Open A BLOB For Incremental I/O
6629 ** CONSTRUCTOR: sqlite3_blob
6631 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
6632 ** in row iRow, column zColumn, table zTable in database zDb;
6633 ** in other words, the same BLOB that would be selected by:
6636 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
6639 ** ^(Parameter zDb is not the filename that contains the database, but
6640 ** rather the symbolic name of the database. For attached databases, this is
6641 ** the name that appears after the AS keyword in the [ATTACH] statement.
6642 ** For the main database file, the database name is "main". For TEMP
6643 ** tables, the database name is "temp".)^
6645 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
6646 ** and write access. ^If the flags parameter is zero, the BLOB is opened for
6647 ** read-only access.
6649 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
6650 ** in *ppBlob. Otherwise an [error code] is returned and, unless the error
6651 ** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
6652 ** the API is not misused, it is always safe to call [sqlite3_blob_close()]
6653 ** on *ppBlob after this function it returns.
6655 ** This function fails with SQLITE_ERROR if any of the following are true:
6657 ** <li> ^(Database zDb does not exist)^,
6658 ** <li> ^(Table zTable does not exist within database zDb)^,
6659 ** <li> ^(Table zTable is a WITHOUT ROWID table)^,
6660 ** <li> ^(Column zColumn does not exist)^,
6661 ** <li> ^(Row iRow is not present in the table)^,
6662 ** <li> ^(The specified column of row iRow contains a value that is not
6663 ** a TEXT or BLOB value)^,
6664 ** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
6665 ** constraint and the blob is being opened for read/write access)^,
6666 ** <li> ^([foreign key constraints | Foreign key constraints] are enabled,
6667 ** column zColumn is part of a [child key] definition and the blob is
6668 ** being opened for read/write access)^.
6671 ** ^Unless it returns SQLITE_MISUSE, this function sets the
6672 ** [database connection] error code and message accessible via
6673 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6675 ** A BLOB referenced by sqlite3_blob_open() may be read using the
6676 ** [sqlite3_blob_read()] interface and modified by using
6677 ** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a
6678 ** different row of the same table using the [sqlite3_blob_reopen()]
6679 ** interface. However, the column, table, or database of a [BLOB handle]
6680 ** cannot be changed after the [BLOB handle] is opened.
6682 ** ^(If the row that a BLOB handle points to is modified by an
6683 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
6684 ** then the BLOB handle is marked as "expired".
6685 ** This is true if any column of the row is changed, even a column
6686 ** other than the one the BLOB handle is open on.)^
6687 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
6688 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
6689 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
6690 ** rolled back by the expiration of the BLOB. Such changes will eventually
6691 ** commit if the transaction continues to completion.)^
6693 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
6694 ** the opened blob. ^The size of a blob may not be changed by this
6695 ** interface. Use the [UPDATE] SQL command to change the size of a
6698 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
6699 ** and the built-in [zeroblob] SQL function may be used to create a
6700 ** zero-filled blob to read or write using the incremental-blob interface.
6702 ** To avoid a resource leak, every open [BLOB handle] should eventually
6703 ** be released by a call to [sqlite3_blob_close()].
6705 ** See also: [sqlite3_blob_close()],
6706 ** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
6707 ** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
6709 SQLITE_API int sqlite3_blob_open(
6713 const char *zColumn,
6716 sqlite3_blob **ppBlob
6720 ** CAPI3REF: Move a BLOB Handle to a New Row
6721 ** METHOD: sqlite3_blob
6723 ** ^This function is used to move an existing [BLOB handle] so that it points
6724 ** to a different row of the same database table. ^The new row is identified
6725 ** by the rowid value passed as the second argument. Only the row can be
6726 ** changed. ^The database, table and column on which the blob handle is open
6727 ** remain the same. Moving an existing [BLOB handle] to a new row is
6728 ** faster than closing the existing handle and opening a new one.
6730 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
6731 ** it must exist and there must be either a blob or text value stored in
6732 ** the nominated column.)^ ^If the new row is not present in the table, or if
6733 ** it does not contain a blob or text value, or if another error occurs, an
6734 ** SQLite error code is returned and the blob handle is considered aborted.
6735 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
6736 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
6737 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
6738 ** always returns zero.
6740 ** ^This function sets the database handle error code and message.
6742 SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
6745 ** CAPI3REF: Close A BLOB Handle
6746 ** DESTRUCTOR: sqlite3_blob
6748 ** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
6749 ** unconditionally. Even if this routine returns an error code, the
6750 ** handle is still closed.)^
6752 ** ^If the blob handle being closed was opened for read-write access, and if
6753 ** the database is in auto-commit mode and there are no other open read-write
6754 ** blob handles or active write statements, the current transaction is
6755 ** committed. ^If an error occurs while committing the transaction, an error
6756 ** code is returned and the transaction rolled back.
6758 ** Calling this function with an argument that is not a NULL pointer or an
6759 ** open blob handle results in undefined behaviour. ^Calling this routine
6760 ** with a null pointer (such as would be returned by a failed call to
6761 ** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
6762 ** is passed a valid open blob handle, the values returned by the
6763 ** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
6765 SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
6768 ** CAPI3REF: Return The Size Of An Open BLOB
6769 ** METHOD: sqlite3_blob
6771 ** ^Returns the size in bytes of the BLOB accessible via the
6772 ** successfully opened [BLOB handle] in its only argument. ^The
6773 ** incremental blob I/O routines can only read or overwriting existing
6774 ** blob content; they cannot change the size of a blob.
6776 ** This routine only works on a [BLOB handle] which has been created
6777 ** by a prior successful call to [sqlite3_blob_open()] and which has not
6778 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6779 ** to this routine results in undefined and probably undesirable behavior.
6781 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
6784 ** CAPI3REF: Read Data From A BLOB Incrementally
6785 ** METHOD: sqlite3_blob
6787 ** ^(This function is used to read data from an open [BLOB handle] into a
6788 ** caller-supplied buffer. N bytes of data are copied into buffer Z
6789 ** from the open BLOB, starting at offset iOffset.)^
6791 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
6792 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
6793 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
6794 ** ^The size of the blob (and hence the maximum value of N+iOffset)
6795 ** can be determined using the [sqlite3_blob_bytes()] interface.
6797 ** ^An attempt to read from an expired [BLOB handle] fails with an
6798 ** error code of [SQLITE_ABORT].
6800 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
6801 ** Otherwise, an [error code] or an [extended error code] is returned.)^
6803 ** This routine only works on a [BLOB handle] which has been created
6804 ** by a prior successful call to [sqlite3_blob_open()] and which has not
6805 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6806 ** to this routine results in undefined and probably undesirable behavior.
6808 ** See also: [sqlite3_blob_write()].
6810 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
6813 ** CAPI3REF: Write Data Into A BLOB Incrementally
6814 ** METHOD: sqlite3_blob
6816 ** ^(This function is used to write data into an open [BLOB handle] from a
6817 ** caller-supplied buffer. N bytes of data are copied from the buffer Z
6818 ** into the open BLOB, starting at offset iOffset.)^
6820 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
6821 ** Otherwise, an [error code] or an [extended error code] is returned.)^
6822 ** ^Unless SQLITE_MISUSE is returned, this function sets the
6823 ** [database connection] error code and message accessible via
6824 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6826 ** ^If the [BLOB handle] passed as the first argument was not opened for
6827 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
6828 ** this function returns [SQLITE_READONLY].
6830 ** This function may only modify the contents of the BLOB; it is
6831 ** not possible to increase the size of a BLOB using this API.
6832 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
6833 ** [SQLITE_ERROR] is returned and no data is written. The size of the
6834 ** BLOB (and hence the maximum value of N+iOffset) can be determined
6835 ** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
6836 ** than zero [SQLITE_ERROR] is returned and no data is written.
6838 ** ^An attempt to write to an expired [BLOB handle] fails with an
6839 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
6840 ** before the [BLOB handle] expired are not rolled back by the
6841 ** expiration of the handle, though of course those changes might
6842 ** have been overwritten by the statement that expired the BLOB handle
6843 ** or by other independent statements.
6845 ** This routine only works on a [BLOB handle] which has been created
6846 ** by a prior successful call to [sqlite3_blob_open()] and which has not
6847 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6848 ** to this routine results in undefined and probably undesirable behavior.
6850 ** See also: [sqlite3_blob_read()].
6852 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
6855 ** CAPI3REF: Virtual File System Objects
6857 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
6858 ** that SQLite uses to interact
6859 ** with the underlying operating system. Most SQLite builds come with a
6860 ** single default VFS that is appropriate for the host computer.
6861 ** New VFSes can be registered and existing VFSes can be unregistered.
6862 ** The following interfaces are provided.
6864 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
6865 ** ^Names are case sensitive.
6866 ** ^Names are zero-terminated UTF-8 strings.
6867 ** ^If there is no match, a NULL pointer is returned.
6868 ** ^If zVfsName is NULL then the default VFS is returned.
6870 ** ^New VFSes are registered with sqlite3_vfs_register().
6871 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
6872 ** ^The same VFS can be registered multiple times without injury.
6873 ** ^To make an existing VFS into the default VFS, register it again
6874 ** with the makeDflt flag set. If two different VFSes with the
6875 ** same name are registered, the behavior is undefined. If a
6876 ** VFS is registered with a name that is NULL or an empty string,
6877 ** then the behavior is undefined.
6879 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
6880 ** ^(If the default VFS is unregistered, another VFS is chosen as
6881 ** the default. The choice for the new VFS is arbitrary.)^
6883 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
6884 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
6885 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
6888 ** CAPI3REF: Mutexes
6890 ** The SQLite core uses these routines for thread
6891 ** synchronization. Though they are intended for internal
6892 ** use by SQLite, code that links against SQLite is
6893 ** permitted to use any of these routines.
6895 ** The SQLite source code contains multiple implementations
6896 ** of these mutex routines. An appropriate implementation
6897 ** is selected automatically at compile-time. The following
6898 ** implementations are available in the SQLite core:
6901 ** <li> SQLITE_MUTEX_PTHREADS
6902 ** <li> SQLITE_MUTEX_W32
6903 ** <li> SQLITE_MUTEX_NOOP
6906 ** The SQLITE_MUTEX_NOOP implementation is a set of routines
6907 ** that does no real locking and is appropriate for use in
6908 ** a single-threaded application. The SQLITE_MUTEX_PTHREADS and
6909 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
6912 ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
6913 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
6914 ** implementation is included with the library. In this case the
6915 ** application must supply a custom mutex implementation using the
6916 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
6917 ** before calling sqlite3_initialize() or any other public sqlite3_
6918 ** function that calls sqlite3_initialize().
6920 ** ^The sqlite3_mutex_alloc() routine allocates a new
6921 ** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
6922 ** routine returns NULL if it is unable to allocate the requested
6923 ** mutex. The argument to sqlite3_mutex_alloc() must one of these
6924 ** integer constants:
6927 ** <li> SQLITE_MUTEX_FAST
6928 ** <li> SQLITE_MUTEX_RECURSIVE
6929 ** <li> SQLITE_MUTEX_STATIC_MASTER
6930 ** <li> SQLITE_MUTEX_STATIC_MEM
6931 ** <li> SQLITE_MUTEX_STATIC_OPEN
6932 ** <li> SQLITE_MUTEX_STATIC_PRNG
6933 ** <li> SQLITE_MUTEX_STATIC_LRU
6934 ** <li> SQLITE_MUTEX_STATIC_PMEM
6935 ** <li> SQLITE_MUTEX_STATIC_APP1
6936 ** <li> SQLITE_MUTEX_STATIC_APP2
6937 ** <li> SQLITE_MUTEX_STATIC_APP3
6938 ** <li> SQLITE_MUTEX_STATIC_VFS1
6939 ** <li> SQLITE_MUTEX_STATIC_VFS2
6940 ** <li> SQLITE_MUTEX_STATIC_VFS3
6943 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
6944 ** cause sqlite3_mutex_alloc() to create
6945 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
6946 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
6947 ** The mutex implementation does not need to make a distinction
6948 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
6949 ** not want to. SQLite will only request a recursive mutex in
6950 ** cases where it really needs one. If a faster non-recursive mutex
6951 ** implementation is available on the host platform, the mutex subsystem
6952 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
6954 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
6955 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
6956 ** a pointer to a static preexisting mutex. ^Nine static mutexes are
6957 ** used by the current version of SQLite. Future versions of SQLite
6958 ** may add additional static mutexes. Static mutexes are for internal
6959 ** use by SQLite only. Applications that use SQLite mutexes should
6960 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
6961 ** SQLITE_MUTEX_RECURSIVE.
6963 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
6964 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
6965 ** returns a different mutex on every call. ^For the static
6966 ** mutex types, the same mutex is returned on every call that has
6967 ** the same type number.
6969 ** ^The sqlite3_mutex_free() routine deallocates a previously
6970 ** allocated dynamic mutex. Attempting to deallocate a static
6971 ** mutex results in undefined behavior.
6973 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
6974 ** to enter a mutex. ^If another thread is already within the mutex,
6975 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
6976 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
6977 ** upon successful entry. ^(Mutexes created using
6978 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
6979 ** In such cases, the
6980 ** mutex must be exited an equal number of times before another thread
6981 ** can enter.)^ If the same thread tries to enter any mutex other
6982 ** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
6984 ** ^(Some systems (for example, Windows 95) do not support the operation
6985 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
6986 ** will always return SQLITE_BUSY. The SQLite core only ever uses
6987 ** sqlite3_mutex_try() as an optimization so this is acceptable
6990 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
6991 ** previously entered by the same thread. The behavior
6992 ** is undefined if the mutex is not currently entered by the
6993 ** calling thread or is not currently allocated.
6995 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
6996 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
6997 ** behave as no-ops.
6999 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
7001 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
7002 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
7003 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
7004 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
7005 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
7008 ** CAPI3REF: Mutex Methods Object
7010 ** An instance of this structure defines the low-level routines
7011 ** used to allocate and use mutexes.
7013 ** Usually, the default mutex implementations provided by SQLite are
7014 ** sufficient, however the application has the option of substituting a custom
7015 ** implementation for specialized deployments or systems for which SQLite
7016 ** does not provide a suitable implementation. In this case, the application
7017 ** creates and populates an instance of this structure to pass
7018 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
7019 ** Additionally, an instance of this structure can be used as an
7020 ** output variable when querying the system for the current mutex
7021 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
7023 ** ^The xMutexInit method defined by this structure is invoked as
7024 ** part of system initialization by the sqlite3_initialize() function.
7025 ** ^The xMutexInit routine is called by SQLite exactly once for each
7026 ** effective call to [sqlite3_initialize()].
7028 ** ^The xMutexEnd method defined by this structure is invoked as
7029 ** part of system shutdown by the sqlite3_shutdown() function. The
7030 ** implementation of this method is expected to release all outstanding
7031 ** resources obtained by the mutex methods implementation, especially
7032 ** those obtained by the xMutexInit method. ^The xMutexEnd()
7033 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
7035 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
7036 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
7037 ** xMutexNotheld) implement the following interfaces (respectively):
7040 ** <li> [sqlite3_mutex_alloc()] </li>
7041 ** <li> [sqlite3_mutex_free()] </li>
7042 ** <li> [sqlite3_mutex_enter()] </li>
7043 ** <li> [sqlite3_mutex_try()] </li>
7044 ** <li> [sqlite3_mutex_leave()] </li>
7045 ** <li> [sqlite3_mutex_held()] </li>
7046 ** <li> [sqlite3_mutex_notheld()] </li>
7049 ** The only difference is that the public sqlite3_XXX functions enumerated
7050 ** above silently ignore any invocations that pass a NULL pointer instead
7051 ** of a valid mutex handle. The implementations of the methods defined
7052 ** by this structure are not required to handle this case, the results
7053 ** of passing a NULL pointer instead of a valid mutex handle are undefined
7054 ** (i.e. it is acceptable to provide an implementation that segfaults if
7055 ** it is passed a NULL pointer).
7057 ** The xMutexInit() method must be threadsafe. It must be harmless to
7058 ** invoke xMutexInit() multiple times within the same process and without
7059 ** intervening calls to xMutexEnd(). Second and subsequent calls to
7060 ** xMutexInit() must be no-ops.
7062 ** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
7063 ** and its associates). Similarly, xMutexAlloc() must not use SQLite memory
7064 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
7065 ** memory allocation for a fast or recursive mutex.
7067 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
7068 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
7069 ** If xMutexInit fails in any way, it is expected to clean up after itself
7070 ** prior to returning.
7072 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
7073 struct sqlite3_mutex_methods {
7074 int (*xMutexInit)(void);
7075 int (*xMutexEnd)(void);
7076 sqlite3_mutex *(*xMutexAlloc)(int);
7077 void (*xMutexFree)(sqlite3_mutex *);
7078 void (*xMutexEnter)(sqlite3_mutex *);
7079 int (*xMutexTry)(sqlite3_mutex *);
7080 void (*xMutexLeave)(sqlite3_mutex *);
7081 int (*xMutexHeld)(sqlite3_mutex *);
7082 int (*xMutexNotheld)(sqlite3_mutex *);
7086 ** CAPI3REF: Mutex Verification Routines
7088 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
7089 ** are intended for use inside assert() statements. The SQLite core
7090 ** never uses these routines except inside an assert() and applications
7091 ** are advised to follow the lead of the core. The SQLite core only
7092 ** provides implementations for these routines when it is compiled
7093 ** with the SQLITE_DEBUG flag. External mutex implementations
7094 ** are only required to provide these routines if SQLITE_DEBUG is
7095 ** defined and if NDEBUG is not defined.
7097 ** These routines should return true if the mutex in their argument
7098 ** is held or not held, respectively, by the calling thread.
7100 ** The implementation is not required to provide versions of these
7101 ** routines that actually work. If the implementation does not provide working
7102 ** versions of these routines, it should at least provide stubs that always
7103 ** return true so that one does not get spurious assertion failures.
7105 ** If the argument to sqlite3_mutex_held() is a NULL pointer then
7106 ** the routine should return 1. This seems counter-intuitive since
7107 ** clearly the mutex cannot be held if it does not exist. But
7108 ** the reason the mutex does not exist is because the build is not
7109 ** using mutexes. And we do not want the assert() containing the
7110 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
7111 ** the appropriate thing to do. The sqlite3_mutex_notheld()
7112 ** interface should also return 1 when given a NULL pointer.
7115 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
7116 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
7120 ** CAPI3REF: Mutex Types
7122 ** The [sqlite3_mutex_alloc()] interface takes a single argument
7123 ** which is one of these integer constants.
7125 ** The set of static mutexes may change from one SQLite release to the
7126 ** next. Applications that override the built-in mutex logic must be
7127 ** prepared to accommodate additional static mutexes.
7129 #define SQLITE_MUTEX_FAST 0
7130 #define SQLITE_MUTEX_RECURSIVE 1
7131 #define SQLITE_MUTEX_STATIC_MASTER 2
7132 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
7133 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
7134 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
7135 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */
7136 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
7137 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
7138 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
7139 #define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */
7140 #define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */
7141 #define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */
7142 #define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */
7143 #define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */
7144 #define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */
7147 ** CAPI3REF: Retrieve the mutex for a database connection
7150 ** ^This interface returns a pointer the [sqlite3_mutex] object that
7151 ** serializes access to the [database connection] given in the argument
7152 ** when the [threading mode] is Serialized.
7153 ** ^If the [threading mode] is Single-thread or Multi-thread then this
7154 ** routine returns a NULL pointer.
7156 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
7159 ** CAPI3REF: Low-Level Control Of Database Files
7161 ** KEYWORDS: {file control}
7163 ** ^The [sqlite3_file_control()] interface makes a direct call to the
7164 ** xFileControl method for the [sqlite3_io_methods] object associated
7165 ** with a particular database identified by the second argument. ^The
7166 ** name of the database is "main" for the main database or "temp" for the
7167 ** TEMP database, or the name that appears after the AS keyword for
7168 ** databases that are added using the [ATTACH] SQL command.
7169 ** ^A NULL pointer can be used in place of "main" to refer to the
7170 ** main database file.
7171 ** ^The third and fourth parameters to this routine
7172 ** are passed directly through to the second and third parameters of
7173 ** the xFileControl method. ^The return value of the xFileControl
7174 ** method becomes the return value of this routine.
7176 ** A few opcodes for [sqlite3_file_control()] are handled directly
7177 ** by the SQLite core and never invoke the
7178 ** sqlite3_io_methods.xFileControl method.
7179 ** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
7180 ** a pointer to the underlying [sqlite3_file] object to be written into
7181 ** the space pointed to by the 4th parameter. The
7182 ** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns
7183 ** the [sqlite3_file] object associated with the journal file instead of
7184 ** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns
7185 ** a pointer to the underlying [sqlite3_vfs] object for the file.
7186 ** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter
7189 ** ^If the second parameter (zDbName) does not match the name of any
7190 ** open database file, then SQLITE_ERROR is returned. ^This error
7191 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
7192 ** or [sqlite3_errmsg()]. The underlying xFileControl method might
7193 ** also return SQLITE_ERROR. There is no way to distinguish between
7194 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
7195 ** xFileControl method.
7197 ** See also: [file control opcodes]
7199 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
7202 ** CAPI3REF: Testing Interface
7204 ** ^The sqlite3_test_control() interface is used to read out internal
7205 ** state of SQLite and to inject faults into SQLite for testing
7206 ** purposes. ^The first parameter is an operation code that determines
7207 ** the number, meaning, and operation of all subsequent parameters.
7209 ** This interface is not for use by applications. It exists solely
7210 ** for verifying the correct operation of the SQLite library. Depending
7211 ** on how the SQLite library is compiled, this interface might not exist.
7213 ** The details of the operation codes, their meanings, the parameters
7214 ** they take, and what they do are all subject to change without notice.
7215 ** Unlike most of the SQLite API, this function is not guaranteed to
7216 ** operate consistently from one release to the next.
7218 SQLITE_API int sqlite3_test_control(int op, ...);
7221 ** CAPI3REF: Testing Interface Operation Codes
7223 ** These constants are the valid operation code parameters used
7224 ** as the first argument to [sqlite3_test_control()].
7226 ** These parameters and their meanings are subject to change
7227 ** without notice. These values are for testing purposes only.
7228 ** Applications should not use any of these parameters or the
7229 ** [sqlite3_test_control()] interface.
7231 #define SQLITE_TESTCTRL_FIRST 5
7232 #define SQLITE_TESTCTRL_PRNG_SAVE 5
7233 #define SQLITE_TESTCTRL_PRNG_RESTORE 6
7234 #define SQLITE_TESTCTRL_PRNG_RESET 7
7235 #define SQLITE_TESTCTRL_BITVEC_TEST 8
7236 #define SQLITE_TESTCTRL_FAULT_INSTALL 9
7237 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
7238 #define SQLITE_TESTCTRL_PENDING_BYTE 11
7239 #define SQLITE_TESTCTRL_ASSERT 12
7240 #define SQLITE_TESTCTRL_ALWAYS 13
7241 #define SQLITE_TESTCTRL_RESERVE 14
7242 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
7243 #define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */
7244 #define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */
7245 #define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17
7246 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
7247 #define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */
7248 #define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19
7249 #define SQLITE_TESTCTRL_NEVER_CORRUPT 20
7250 #define SQLITE_TESTCTRL_VDBE_COVERAGE 21
7251 #define SQLITE_TESTCTRL_BYTEORDER 22
7252 #define SQLITE_TESTCTRL_ISINIT 23
7253 #define SQLITE_TESTCTRL_SORTER_MMAP 24
7254 #define SQLITE_TESTCTRL_IMPOSTER 25
7255 #define SQLITE_TESTCTRL_PARSER_COVERAGE 26
7256 #define SQLITE_TESTCTRL_LAST 26 /* Largest TESTCTRL */
7259 ** CAPI3REF: SQL Keyword Checking
7261 ** These routines provide access to the set of SQL language keywords
7262 ** recognized by SQLite. Applications can uses these routines to determine
7263 ** whether or not a specific identifier needs to be escaped (for example,
7264 ** by enclosing in double-quotes) so as not to confuse the parser.
7266 ** The sqlite3_keyword_count() interface returns the number of distinct
7267 ** keywords understood by SQLite.
7269 ** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and
7270 ** makes *Z point to that keyword expressed as UTF8 and writes the number
7271 ** of bytes in the keyword into *L. The string that *Z points to is not
7272 ** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns
7273 ** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
7274 ** or L are NULL or invalid pointers then calls to
7275 ** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
7277 ** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
7278 ** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
7279 ** if it is and zero if not.
7281 ** The parser used by SQLite is forgiving. It is often possible to use
7282 ** a keyword as an identifier as long as such use does not result in a
7283 ** parsing ambiguity. For example, the statement
7284 ** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
7285 ** creates a new table named "BEGIN" with three columns named
7286 ** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid
7287 ** using keywords as identifiers. Common techniques used to avoid keyword
7288 ** name collisions include:
7290 ** <li> Put all identifier names inside double-quotes. This is the official
7291 ** SQL way to escape identifier names.
7292 ** <li> Put identifier names inside [...]. This is not standard SQL,
7293 ** but it is what SQL Server does and so lots of programmers use this
7295 ** <li> Begin every identifier with the letter "Z" as no SQL keywords start
7297 ** <li> Include a digit somewhere in every identifier name.
7300 ** Note that the number of keywords understood by SQLite can depend on
7301 ** compile-time options. For example, "VACUUM" is not a keyword if
7302 ** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also,
7303 ** new keywords may be added to future releases of SQLite.
7305 SQLITE_API int sqlite3_keyword_count(void);
7306 SQLITE_API int sqlite3_keyword_name(int,const char**,int*);
7307 SQLITE_API int sqlite3_keyword_check(const char*,int);
7310 ** CAPI3REF: Dynamic String Object
7311 ** KEYWORDS: {dynamic string}
7313 ** An instance of the sqlite3_str object contains a dynamically-sized
7314 ** string under construction.
7316 ** The lifecycle of an sqlite3_str object is as follows:
7318 ** <li> ^The sqlite3_str object is created using [sqlite3_str_new()].
7319 ** <li> ^Text is appended to the sqlite3_str object using various
7320 ** methods, such as [sqlite3_str_appendf()].
7321 ** <li> ^The sqlite3_str object is destroyed and the string it created
7322 ** is returned using the [sqlite3_str_finish()] interface.
7325 typedef struct sqlite3_str sqlite3_str;
7328 ** CAPI3REF: Create A New Dynamic String Object
7329 ** CONSTRUCTOR: sqlite3_str
7331 ** ^The [sqlite3_str_new(D)] interface allocates and initializes
7332 ** a new [sqlite3_str] object. To avoid memory leaks, the object returned by
7333 ** [sqlite3_str_new()] must be freed by a subsequent call to
7334 ** [sqlite3_str_finish(X)].
7336 ** ^The [sqlite3_str_new(D)] interface always returns a pointer to a
7337 ** valid [sqlite3_str] object, though in the event of an out-of-memory
7338 ** error the returned object might be a special singleton that will
7339 ** silently reject new text, always return SQLITE_NOMEM from
7340 ** [sqlite3_str_errcode()], always return 0 for
7341 ** [sqlite3_str_length()], and always return NULL from
7342 ** [sqlite3_str_finish(X)]. It is always safe to use the value
7343 ** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter
7344 ** to any of the other [sqlite3_str] methods.
7346 ** The D parameter to [sqlite3_str_new(D)] may be NULL. If the
7347 ** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum
7348 ** length of the string contained in the [sqlite3_str] object will be
7349 ** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead
7350 ** of [SQLITE_MAX_LENGTH].
7352 SQLITE_API sqlite3_str *sqlite3_str_new(sqlite3*);
7355 ** CAPI3REF: Finalize A Dynamic String
7356 ** DESTRUCTOR: sqlite3_str
7358 ** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
7359 ** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
7360 ** that contains the constructed string. The calling application should
7361 ** pass the returned value to [sqlite3_free()] to avoid a memory leak.
7362 ** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
7363 ** errors were encountered during construction of the string. ^The
7364 ** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the
7365 ** string in [sqlite3_str] object X is zero bytes long.
7367 SQLITE_API char *sqlite3_str_finish(sqlite3_str*);
7370 ** CAPI3REF: Add Content To A Dynamic String
7371 ** METHOD: sqlite3_str
7373 ** These interfaces add content to an sqlite3_str object previously obtained
7374 ** from [sqlite3_str_new()].
7376 ** ^The [sqlite3_str_appendf(X,F,...)] and
7377 ** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
7378 ** functionality of SQLite to append formatted text onto the end of
7379 ** [sqlite3_str] object X.
7381 ** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
7382 ** onto the end of the [sqlite3_str] object X. N must be non-negative.
7383 ** S must contain at least N non-zero bytes of content. To append a
7384 ** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
7387 ** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of
7388 ** zero-terminated string S onto the end of [sqlite3_str] object X.
7390 ** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
7391 ** single-byte character C onto the end of [sqlite3_str] object X.
7392 ** ^This method can be used, for example, to add whitespace indentation.
7394 ** ^The [sqlite3_str_reset(X)] method resets the string under construction
7395 ** inside [sqlite3_str] object X back to zero bytes in length.
7397 ** These methods do not return a result code. ^If an error occurs, that fact
7398 ** is recorded in the [sqlite3_str] object and can be recovered by a
7399 ** subsequent call to [sqlite3_str_errcode(X)].
7401 SQLITE_API void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
7402 SQLITE_API void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
7403 SQLITE_API void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
7404 SQLITE_API void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
7405 SQLITE_API void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
7406 SQLITE_API void sqlite3_str_reset(sqlite3_str*);
7409 ** CAPI3REF: Status Of A Dynamic String
7410 ** METHOD: sqlite3_str
7412 ** These interfaces return the current status of an [sqlite3_str] object.
7414 ** ^If any prior errors have occurred while constructing the dynamic string
7415 ** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
7416 ** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns
7417 ** [SQLITE_NOMEM] following any out-of-memory error, or
7418 ** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
7419 ** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
7421 ** ^The [sqlite3_str_length(X)] method returns the current length, in bytes,
7422 ** of the dynamic string under construction in [sqlite3_str] object X.
7423 ** ^The length returned by [sqlite3_str_length(X)] does not include the
7424 ** zero-termination byte.
7426 ** ^The [sqlite3_str_value(X)] method returns a pointer to the current
7427 ** content of the dynamic string under construction in X. The value
7428 ** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
7429 ** and might be freed or altered by any subsequent method on the same
7430 ** [sqlite3_str] object. Applications must not used the pointer returned
7431 ** [sqlite3_str_value(X)] after any subsequent method call on the same
7432 ** object. ^Applications may change the content of the string returned
7433 ** by [sqlite3_str_value(X)] as long as they do not write into any bytes
7434 ** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
7435 ** write any byte after any subsequent sqlite3_str method call.
7437 SQLITE_API int sqlite3_str_errcode(sqlite3_str*);
7438 SQLITE_API int sqlite3_str_length(sqlite3_str*);
7439 SQLITE_API char *sqlite3_str_value(sqlite3_str*);
7442 ** CAPI3REF: SQLite Runtime Status
7444 ** ^These interfaces are used to retrieve runtime status information
7445 ** about the performance of SQLite, and optionally to reset various
7446 ** highwater marks. ^The first argument is an integer code for
7447 ** the specific parameter to measure. ^(Recognized integer codes
7448 ** are of the form [status parameters | SQLITE_STATUS_...].)^
7449 ** ^The current value of the parameter is returned into *pCurrent.
7450 ** ^The highest recorded value is returned in *pHighwater. ^If the
7451 ** resetFlag is true, then the highest record value is reset after
7452 ** *pHighwater is written. ^(Some parameters do not record the highest
7453 ** value. For those parameters
7454 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
7455 ** ^(Other parameters record only the highwater mark and not the current
7456 ** value. For these latter parameters nothing is written into *pCurrent.)^
7458 ** ^The sqlite3_status() and sqlite3_status64() routines return
7459 ** SQLITE_OK on success and a non-zero [error code] on failure.
7461 ** If either the current value or the highwater mark is too large to
7462 ** be represented by a 32-bit integer, then the values returned by
7463 ** sqlite3_status() are undefined.
7465 ** See also: [sqlite3_db_status()]
7467 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
7468 SQLITE_API int sqlite3_status64(
7470 sqlite3_int64 *pCurrent,
7471 sqlite3_int64 *pHighwater,
7477 ** CAPI3REF: Status Parameters
7478 ** KEYWORDS: {status parameters}
7480 ** These integer constants designate various run-time status parameters
7481 ** that can be returned by [sqlite3_status()].
7484 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
7485 ** <dd>This parameter is the current amount of memory checked out
7486 ** using [sqlite3_malloc()], either directly or indirectly. The
7487 ** figure includes calls made to [sqlite3_malloc()] by the application
7488 ** and internal memory usage by the SQLite library. Auxiliary page-cache
7489 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
7490 ** this parameter. The amount returned is the sum of the allocation
7491 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
7493 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
7494 ** <dd>This parameter records the largest memory allocation request
7495 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
7496 ** internal equivalents). Only the value returned in the
7497 ** *pHighwater parameter to [sqlite3_status()] is of interest.
7498 ** The value written into the *pCurrent parameter is undefined.</dd>)^
7500 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
7501 ** <dd>This parameter records the number of separate memory allocations
7502 ** currently checked out.</dd>)^
7504 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
7505 ** <dd>This parameter returns the number of pages used out of the
7506 ** [pagecache memory allocator] that was configured using
7507 ** [SQLITE_CONFIG_PAGECACHE]. The
7508 ** value returned is in pages, not in bytes.</dd>)^
7510 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
7511 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
7512 ** <dd>This parameter returns the number of bytes of page cache
7513 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
7514 ** buffer and where forced to overflow to [sqlite3_malloc()]. The
7515 ** returned value includes allocations that overflowed because they
7516 ** where too large (they were larger than the "sz" parameter to
7517 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
7518 ** no space was left in the page cache.</dd>)^
7520 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
7521 ** <dd>This parameter records the largest memory allocation request
7522 ** handed to [pagecache memory allocator]. Only the value returned in the
7523 ** *pHighwater parameter to [sqlite3_status()] is of interest.
7524 ** The value written into the *pCurrent parameter is undefined.</dd>)^
7526 ** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
7527 ** <dd>No longer used.</dd>
7529 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
7530 ** <dd>No longer used.</dd>
7532 ** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
7533 ** <dd>No longer used.</dd>
7535 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
7536 ** <dd>The *pHighwater parameter records the deepest parser stack.
7537 ** The *pCurrent value is undefined. The *pHighwater value is only
7538 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
7541 ** New status parameters may be added from time to time.
7543 #define SQLITE_STATUS_MEMORY_USED 0
7544 #define SQLITE_STATUS_PAGECACHE_USED 1
7545 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
7546 #define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */
7547 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */
7548 #define SQLITE_STATUS_MALLOC_SIZE 5
7549 #define SQLITE_STATUS_PARSER_STACK 6
7550 #define SQLITE_STATUS_PAGECACHE_SIZE 7
7551 #define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */
7552 #define SQLITE_STATUS_MALLOC_COUNT 9
7555 ** CAPI3REF: Database Connection Status
7558 ** ^This interface is used to retrieve runtime status information
7559 ** about a single [database connection]. ^The first argument is the
7560 ** database connection object to be interrogated. ^The second argument
7561 ** is an integer constant, taken from the set of
7562 ** [SQLITE_DBSTATUS options], that
7563 ** determines the parameter to interrogate. The set of
7564 ** [SQLITE_DBSTATUS options] is likely
7565 ** to grow in future releases of SQLite.
7567 ** ^The current value of the requested parameter is written into *pCur
7568 ** and the highest instantaneous value is written into *pHiwtr. ^If
7569 ** the resetFlg is true, then the highest instantaneous value is
7570 ** reset back down to the current value.
7572 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
7573 ** non-zero [error code] on failure.
7575 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
7577 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
7580 ** CAPI3REF: Status Parameters for database connections
7581 ** KEYWORDS: {SQLITE_DBSTATUS options}
7583 ** These constants are the available integer "verbs" that can be passed as
7584 ** the second argument to the [sqlite3_db_status()] interface.
7586 ** New verbs may be added in future releases of SQLite. Existing verbs
7587 ** might be discontinued. Applications should check the return code from
7588 ** [sqlite3_db_status()] to make sure that the call worked.
7589 ** The [sqlite3_db_status()] interface will return a non-zero error code
7590 ** if a discontinued or unsupported verb is invoked.
7593 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
7594 ** <dd>This parameter returns the number of lookaside memory slots currently
7595 ** checked out.</dd>)^
7597 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
7598 ** <dd>This parameter returns the number malloc attempts that were
7599 ** satisfied using lookaside memory. Only the high-water value is meaningful;
7600 ** the current value is always zero.)^
7602 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
7603 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
7604 ** <dd>This parameter returns the number malloc attempts that might have
7605 ** been satisfied using lookaside memory but failed due to the amount of
7606 ** memory requested being larger than the lookaside slot size.
7607 ** Only the high-water value is meaningful;
7608 ** the current value is always zero.)^
7610 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
7611 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
7612 ** <dd>This parameter returns the number malloc attempts that might have
7613 ** been satisfied using lookaside memory but failed due to all lookaside
7614 ** memory already being in use.
7615 ** Only the high-water value is meaningful;
7616 ** the current value is always zero.)^
7618 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
7619 ** <dd>This parameter returns the approximate number of bytes of heap
7620 ** memory used by all pager caches associated with the database connection.)^
7621 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
7623 ** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
7624 ** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
7625 ** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
7626 ** pager cache is shared between two or more connections the bytes of heap
7627 ** memory used by that pager cache is divided evenly between the attached
7628 ** connections.)^ In other words, if none of the pager caches associated
7629 ** with the database connection are shared, this request returns the same
7630 ** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
7631 ** shared, the value returned by this call will be smaller than that returned
7632 ** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
7633 ** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
7635 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
7636 ** <dd>This parameter returns the approximate number of bytes of heap
7637 ** memory used to store the schema for all databases associated
7638 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
7639 ** ^The full amount of memory used by the schemas is reported, even if the
7640 ** schema memory is shared with other database connections due to
7641 ** [shared cache mode] being enabled.
7642 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
7644 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
7645 ** <dd>This parameter returns the approximate number of bytes of heap
7646 ** and lookaside memory used by all prepared statements associated with
7647 ** the database connection.)^
7648 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
7651 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
7652 ** <dd>This parameter returns the number of pager cache hits that have
7653 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
7657 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
7658 ** <dd>This parameter returns the number of pager cache misses that have
7659 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
7663 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
7664 ** <dd>This parameter returns the number of dirty cache entries that have
7665 ** been written to disk. Specifically, the number of pages written to the
7666 ** wal file in wal mode databases, or the number of pages written to the
7667 ** database file in rollback mode databases. Any pages written as part of
7668 ** transaction rollback or database recovery operations are not included.
7669 ** If an IO or other error occurs while writing a page to disk, the effect
7670 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
7671 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
7674 ** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
7675 ** <dd>This parameter returns the number of dirty cache entries that have
7676 ** been written to disk in the middle of a transaction due to the page
7677 ** cache overflowing. Transactions are more efficient if they are written
7678 ** to disk all at once. When pages spill mid-transaction, that introduces
7679 ** additional overhead. This parameter can be used help identify
7680 ** inefficiencies that can be resolve by increasing the cache size.
7683 ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
7684 ** <dd>This parameter returns zero for the current value if and only if
7685 ** all foreign key constraints (deferred or immediate) have been
7686 ** resolved.)^ ^The highwater mark is always 0.
7690 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
7691 #define SQLITE_DBSTATUS_CACHE_USED 1
7692 #define SQLITE_DBSTATUS_SCHEMA_USED 2
7693 #define SQLITE_DBSTATUS_STMT_USED 3
7694 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
7695 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
7696 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
7697 #define SQLITE_DBSTATUS_CACHE_HIT 7
7698 #define SQLITE_DBSTATUS_CACHE_MISS 8
7699 #define SQLITE_DBSTATUS_CACHE_WRITE 9
7700 #define SQLITE_DBSTATUS_DEFERRED_FKS 10
7701 #define SQLITE_DBSTATUS_CACHE_USED_SHARED 11
7702 #define SQLITE_DBSTATUS_CACHE_SPILL 12
7703 #define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */
7707 ** CAPI3REF: Prepared Statement Status
7708 ** METHOD: sqlite3_stmt
7710 ** ^(Each prepared statement maintains various
7711 ** [SQLITE_STMTSTATUS counters] that measure the number
7712 ** of times it has performed specific operations.)^ These counters can
7713 ** be used to monitor the performance characteristics of the prepared
7714 ** statements. For example, if the number of table steps greatly exceeds
7715 ** the number of table searches or result rows, that would tend to indicate
7716 ** that the prepared statement is using a full table scan rather than
7719 ** ^(This interface is used to retrieve and reset counter values from
7720 ** a [prepared statement]. The first argument is the prepared statement
7721 ** object to be interrogated. The second argument
7722 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
7723 ** to be interrogated.)^
7724 ** ^The current value of the requested counter is returned.
7725 ** ^If the resetFlg is true, then the counter is reset to zero after this
7726 ** interface call returns.
7728 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
7730 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
7733 ** CAPI3REF: Status Parameters for prepared statements
7734 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
7736 ** These preprocessor macros define integer codes that name counter
7737 ** values associated with the [sqlite3_stmt_status()] interface.
7738 ** The meanings of the various counters are as follows:
7741 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
7742 ** <dd>^This is the number of times that SQLite has stepped forward in
7743 ** a table as part of a full table scan. Large numbers for this counter
7744 ** may indicate opportunities for performance improvement through
7745 ** careful use of indices.</dd>
7747 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
7748 ** <dd>^This is the number of sort operations that have occurred.
7749 ** A non-zero value in this counter may indicate an opportunity to
7750 ** improvement performance through careful use of indices.</dd>
7752 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
7753 ** <dd>^This is the number of rows inserted into transient indices that
7754 ** were created automatically in order to help joins run faster.
7755 ** A non-zero value in this counter may indicate an opportunity to
7756 ** improvement performance by adding permanent indices that do not
7757 ** need to be reinitialized each time the statement is run.</dd>
7759 ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
7760 ** <dd>^This is the number of virtual machine operations executed
7761 ** by the prepared statement if that number is less than or equal
7762 ** to 2147483647. The number of virtual machine operations can be
7763 ** used as a proxy for the total work done by the prepared statement.
7764 ** If the number of virtual machine operations exceeds 2147483647
7765 ** then the value returned by this statement status code is undefined.
7767 ** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
7768 ** <dd>^This is the number of times that the prepare statement has been
7769 ** automatically regenerated due to schema changes or change to
7770 ** [bound parameters] that might affect the query plan.
7772 ** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
7773 ** <dd>^This is the number of times that the prepared statement has
7774 ** been run. A single "run" for the purposes of this counter is one
7775 ** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
7776 ** The counter is incremented on the first [sqlite3_step()] call of each
7779 ** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
7780 ** <dd>^This is the approximate number of bytes of heap memory
7781 ** used to store the prepared statement. ^This value is not actually
7782 ** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
7783 ** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
7787 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
7788 #define SQLITE_STMTSTATUS_SORT 2
7789 #define SQLITE_STMTSTATUS_AUTOINDEX 3
7790 #define SQLITE_STMTSTATUS_VM_STEP 4
7791 #define SQLITE_STMTSTATUS_REPREPARE 5
7792 #define SQLITE_STMTSTATUS_RUN 6
7793 #define SQLITE_STMTSTATUS_MEMUSED 99
7796 ** CAPI3REF: Custom Page Cache Object
7798 ** The sqlite3_pcache type is opaque. It is implemented by
7799 ** the pluggable module. The SQLite core has no knowledge of
7800 ** its size or internal structure and never deals with the
7801 ** sqlite3_pcache object except by holding and passing pointers
7804 ** See [sqlite3_pcache_methods2] for additional information.
7806 typedef struct sqlite3_pcache sqlite3_pcache;
7809 ** CAPI3REF: Custom Page Cache Object
7811 ** The sqlite3_pcache_page object represents a single page in the
7812 ** page cache. The page cache will allocate instances of this
7813 ** object. Various methods of the page cache use pointers to instances
7814 ** of this object as parameters or as their return value.
7816 ** See [sqlite3_pcache_methods2] for additional information.
7818 typedef struct sqlite3_pcache_page sqlite3_pcache_page;
7819 struct sqlite3_pcache_page {
7820 void *pBuf; /* The content of the page */
7821 void *pExtra; /* Extra information associated with the page */
7825 ** CAPI3REF: Application Defined Page Cache.
7826 ** KEYWORDS: {page cache}
7828 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
7829 ** register an alternative page cache implementation by passing in an
7830 ** instance of the sqlite3_pcache_methods2 structure.)^
7831 ** In many applications, most of the heap memory allocated by
7832 ** SQLite is used for the page cache.
7833 ** By implementing a
7834 ** custom page cache using this API, an application can better control
7835 ** the amount of memory consumed by SQLite, the way in which
7836 ** that memory is allocated and released, and the policies used to
7837 ** determine exactly which parts of a database file are cached and for
7840 ** The alternative page cache mechanism is an
7841 ** extreme measure that is only needed by the most demanding applications.
7842 ** The built-in page cache is recommended for most uses.
7844 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
7845 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
7846 ** the application may discard the parameter after the call to
7847 ** [sqlite3_config()] returns.)^
7849 ** [[the xInit() page cache method]]
7850 ** ^(The xInit() method is called once for each effective
7851 ** call to [sqlite3_initialize()])^
7852 ** (usually only once during the lifetime of the process). ^(The xInit()
7853 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
7854 ** The intent of the xInit() method is to set up global data structures
7855 ** required by the custom page cache implementation.
7856 ** ^(If the xInit() method is NULL, then the
7857 ** built-in default page cache is used instead of the application defined
7860 ** [[the xShutdown() page cache method]]
7861 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
7862 ** It can be used to clean up
7863 ** any outstanding resources before process shutdown, if required.
7864 ** ^The xShutdown() method may be NULL.
7866 ** ^SQLite automatically serializes calls to the xInit method,
7867 ** so the xInit method need not be threadsafe. ^The
7868 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
7869 ** not need to be threadsafe either. All other methods must be threadsafe
7870 ** in multithreaded applications.
7872 ** ^SQLite will never invoke xInit() more than once without an intervening
7873 ** call to xShutdown().
7875 ** [[the xCreate() page cache methods]]
7876 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
7877 ** SQLite will typically create one cache instance for each open database file,
7878 ** though this is not guaranteed. ^The
7879 ** first parameter, szPage, is the size in bytes of the pages that must
7880 ** be allocated by the cache. ^szPage will always a power of two. ^The
7881 ** second parameter szExtra is a number of bytes of extra storage
7882 ** associated with each page cache entry. ^The szExtra parameter will
7883 ** a number less than 250. SQLite will use the
7884 ** extra szExtra bytes on each page to store metadata about the underlying
7885 ** database page on disk. The value passed into szExtra depends
7886 ** on the SQLite version, the target platform, and how SQLite was compiled.
7887 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
7888 ** created will be used to cache database pages of a file stored on disk, or
7889 ** false if it is used for an in-memory database. The cache implementation
7890 ** does not have to do anything special based with the value of bPurgeable;
7891 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
7892 ** never invoke xUnpin() except to deliberately delete a page.
7893 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
7894 ** false will always have the "discard" flag set to true.
7895 ** ^Hence, a cache created with bPurgeable false will
7896 ** never contain any unpinned pages.
7898 ** [[the xCachesize() page cache method]]
7899 ** ^(The xCachesize() method may be called at any time by SQLite to set the
7900 ** suggested maximum cache-size (number of pages stored by) the cache
7901 ** instance passed as the first argument. This is the value configured using
7902 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
7903 ** parameter, the implementation is not required to do anything with this
7904 ** value; it is advisory only.
7906 ** [[the xPagecount() page cache methods]]
7907 ** The xPagecount() method must return the number of pages currently
7908 ** stored in the cache, both pinned and unpinned.
7910 ** [[the xFetch() page cache methods]]
7911 ** The xFetch() method locates a page in the cache and returns a pointer to
7912 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
7913 ** The pBuf element of the returned sqlite3_pcache_page object will be a
7914 ** pointer to a buffer of szPage bytes used to store the content of a
7915 ** single database page. The pExtra element of sqlite3_pcache_page will be
7916 ** a pointer to the szExtra bytes of extra storage that SQLite has requested
7917 ** for each entry in the page cache.
7919 ** The page to be fetched is determined by the key. ^The minimum key value
7920 ** is 1. After it has been retrieved using xFetch, the page is considered
7923 ** If the requested page is already in the page cache, then the page cache
7924 ** implementation must return a pointer to the page buffer with its content
7925 ** intact. If the requested page is not already in the cache, then the
7926 ** cache implementation should use the value of the createFlag
7927 ** parameter to help it determined what action to take:
7929 ** <table border=1 width=85% align=center>
7930 ** <tr><th> createFlag <th> Behavior when page is not already in cache
7931 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
7932 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
7933 ** Otherwise return NULL.
7934 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
7935 ** NULL if allocating a new page is effectively impossible.
7938 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
7939 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
7940 ** failed.)^ In between the to xFetch() calls, SQLite may
7941 ** attempt to unpin one or more cache pages by spilling the content of
7942 ** pinned pages to disk and synching the operating system disk cache.
7944 ** [[the xUnpin() page cache method]]
7945 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
7946 ** as its second argument. If the third parameter, discard, is non-zero,
7947 ** then the page must be evicted from the cache.
7948 ** ^If the discard parameter is
7949 ** zero, then the page may be discarded or retained at the discretion of
7950 ** page cache implementation. ^The page cache implementation
7951 ** may choose to evict unpinned pages at any time.
7953 ** The cache must not perform any reference counting. A single
7954 ** call to xUnpin() unpins the page regardless of the number of prior calls
7957 ** [[the xRekey() page cache methods]]
7958 ** The xRekey() method is used to change the key value associated with the
7959 ** page passed as the second argument. If the cache
7960 ** previously contains an entry associated with newKey, it must be
7961 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
7964 ** When SQLite calls the xTruncate() method, the cache must discard all
7965 ** existing cache entries with page numbers (keys) greater than or equal
7966 ** to the value of the iLimit parameter passed to xTruncate(). If any
7967 ** of these pages are pinned, they are implicitly unpinned, meaning that
7968 ** they can be safely discarded.
7970 ** [[the xDestroy() page cache method]]
7971 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
7972 ** All resources associated with the specified cache should be freed. ^After
7973 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
7974 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
7977 ** [[the xShrink() page cache method]]
7978 ** ^SQLite invokes the xShrink() method when it wants the page cache to
7979 ** free up as much of heap memory as possible. The page cache implementation
7980 ** is not obligated to free any memory, but well-behaved implementations should
7983 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
7984 struct sqlite3_pcache_methods2 {
7987 int (*xInit)(void*);
7988 void (*xShutdown)(void*);
7989 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
7990 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
7991 int (*xPagecount)(sqlite3_pcache*);
7992 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
7993 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
7994 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
7995 unsigned oldKey, unsigned newKey);
7996 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
7997 void (*xDestroy)(sqlite3_pcache*);
7998 void (*xShrink)(sqlite3_pcache*);
8002 ** This is the obsolete pcache_methods object that has now been replaced
8003 ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
8004 ** retained in the header file for backwards compatibility only.
8006 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
8007 struct sqlite3_pcache_methods {
8009 int (*xInit)(void*);
8010 void (*xShutdown)(void*);
8011 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
8012 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
8013 int (*xPagecount)(sqlite3_pcache*);
8014 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
8015 void (*xUnpin)(sqlite3_pcache*, void*, int discard);
8016 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
8017 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
8018 void (*xDestroy)(sqlite3_pcache*);
8023 ** CAPI3REF: Online Backup Object
8025 ** The sqlite3_backup object records state information about an ongoing
8026 ** online backup operation. ^The sqlite3_backup object is created by
8027 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
8028 ** [sqlite3_backup_finish()].
8030 ** See Also: [Using the SQLite Online Backup API]
8032 typedef struct sqlite3_backup sqlite3_backup;
8035 ** CAPI3REF: Online Backup API.
8037 ** The backup API copies the content of one database into another.
8038 ** It is useful either for creating backups of databases or
8039 ** for copying in-memory databases to or from persistent files.
8041 ** See Also: [Using the SQLite Online Backup API]
8043 ** ^SQLite holds a write transaction open on the destination database file
8044 ** for the duration of the backup operation.
8045 ** ^The source database is read-locked only while it is being read;
8046 ** it is not locked continuously for the entire backup operation.
8047 ** ^Thus, the backup may be performed on a live source database without
8048 ** preventing other database connections from
8049 ** reading or writing to the source database while the backup is underway.
8051 ** ^(To perform a backup operation:
8053 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
8055 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
8056 ** the data between the two databases, and finally
8057 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
8058 ** associated with the backup operation.
8060 ** There should be exactly one call to sqlite3_backup_finish() for each
8061 ** successful call to sqlite3_backup_init().
8063 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
8065 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
8066 ** [database connection] associated with the destination database
8067 ** and the database name, respectively.
8068 ** ^The database name is "main" for the main database, "temp" for the
8069 ** temporary database, or the name specified after the AS keyword in
8070 ** an [ATTACH] statement for an attached database.
8071 ** ^The S and M arguments passed to
8072 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
8073 ** and database name of the source database, respectively.
8074 ** ^The source and destination [database connections] (parameters S and D)
8075 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
8078 ** ^A call to sqlite3_backup_init() will fail, returning NULL, if
8079 ** there is already a read or read-write transaction open on the
8080 ** destination database.
8082 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
8083 ** returned and an error code and error message are stored in the
8084 ** destination [database connection] D.
8085 ** ^The error code and message for the failed call to sqlite3_backup_init()
8086 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
8087 ** [sqlite3_errmsg16()] functions.
8088 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
8089 ** [sqlite3_backup] object.
8090 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
8091 ** sqlite3_backup_finish() functions to perform the specified backup
8094 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
8096 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
8097 ** the source and destination databases specified by [sqlite3_backup] object B.
8098 ** ^If N is negative, all remaining source pages are copied.
8099 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
8100 ** are still more pages to be copied, then the function returns [SQLITE_OK].
8101 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
8102 ** from source to destination, then it returns [SQLITE_DONE].
8103 ** ^If an error occurs while running sqlite3_backup_step(B,N),
8104 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
8105 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
8106 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
8107 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
8109 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
8111 ** <li> the destination database was opened read-only, or
8112 ** <li> the destination database is using write-ahead-log journaling
8113 ** and the destination and source page sizes differ, or
8114 ** <li> the destination database is an in-memory database and the
8115 ** destination and source page sizes differ.
8118 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
8119 ** the [sqlite3_busy_handler | busy-handler function]
8120 ** is invoked (if one is specified). ^If the
8121 ** busy-handler returns non-zero before the lock is available, then
8122 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
8123 ** sqlite3_backup_step() can be retried later. ^If the source
8124 ** [database connection]
8125 ** is being used to write to the source database when sqlite3_backup_step()
8126 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
8127 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
8128 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
8129 ** [SQLITE_READONLY] is returned, then
8130 ** there is no point in retrying the call to sqlite3_backup_step(). These
8131 ** errors are considered fatal.)^ The application must accept
8132 ** that the backup operation has failed and pass the backup operation handle
8133 ** to the sqlite3_backup_finish() to release associated resources.
8135 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
8136 ** on the destination file. ^The exclusive lock is not released until either
8137 ** sqlite3_backup_finish() is called or the backup operation is complete
8138 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
8139 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
8140 ** lasts for the duration of the sqlite3_backup_step() call.
8141 ** ^Because the source database is not locked between calls to
8142 ** sqlite3_backup_step(), the source database may be modified mid-way
8143 ** through the backup process. ^If the source database is modified by an
8144 ** external process or via a database connection other than the one being
8145 ** used by the backup operation, then the backup will be automatically
8146 ** restarted by the next call to sqlite3_backup_step(). ^If the source
8147 ** database is modified by the using the same database connection as is used
8148 ** by the backup operation, then the backup database is automatically
8149 ** updated at the same time.
8151 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
8153 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
8154 ** application wishes to abandon the backup operation, the application
8155 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
8156 ** ^The sqlite3_backup_finish() interfaces releases all
8157 ** resources associated with the [sqlite3_backup] object.
8158 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
8159 ** active write-transaction on the destination database is rolled back.
8160 ** The [sqlite3_backup] object is invalid
8161 ** and may not be used following a call to sqlite3_backup_finish().
8163 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
8164 ** sqlite3_backup_step() errors occurred, regardless or whether or not
8165 ** sqlite3_backup_step() completed.
8166 ** ^If an out-of-memory condition or IO error occurred during any prior
8167 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
8168 ** sqlite3_backup_finish() returns the corresponding [error code].
8170 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
8171 ** is not a permanent error and does not affect the return value of
8172 ** sqlite3_backup_finish().
8174 ** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
8175 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
8177 ** ^The sqlite3_backup_remaining() routine returns the number of pages still
8178 ** to be backed up at the conclusion of the most recent sqlite3_backup_step().
8179 ** ^The sqlite3_backup_pagecount() routine returns the total number of pages
8180 ** in the source database at the conclusion of the most recent
8181 ** sqlite3_backup_step().
8182 ** ^(The values returned by these functions are only updated by
8183 ** sqlite3_backup_step(). If the source database is modified in a way that
8184 ** changes the size of the source database or the number of pages remaining,
8185 ** those changes are not reflected in the output of sqlite3_backup_pagecount()
8186 ** and sqlite3_backup_remaining() until after the next
8187 ** sqlite3_backup_step().)^
8189 ** <b>Concurrent Usage of Database Handles</b>
8191 ** ^The source [database connection] may be used by the application for other
8192 ** purposes while a backup operation is underway or being initialized.
8193 ** ^If SQLite is compiled and configured to support threadsafe database
8194 ** connections, then the source database connection may be used concurrently
8195 ** from within other threads.
8197 ** However, the application must guarantee that the destination
8198 ** [database connection] is not passed to any other API (by any thread) after
8199 ** sqlite3_backup_init() is called and before the corresponding call to
8200 ** sqlite3_backup_finish(). SQLite does not currently check to see
8201 ** if the application incorrectly accesses the destination [database connection]
8202 ** and so no error code is reported, but the operations may malfunction
8203 ** nevertheless. Use of the destination database connection while a
8204 ** backup is in progress might also also cause a mutex deadlock.
8206 ** If running in [shared cache mode], the application must
8207 ** guarantee that the shared cache used by the destination database
8208 ** is not accessed while the backup is running. In practice this means
8209 ** that the application must guarantee that the disk file being
8210 ** backed up to is not accessed by any connection within the process,
8211 ** not just the specific connection that was passed to sqlite3_backup_init().
8213 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
8214 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
8215 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
8216 ** APIs are not strictly speaking threadsafe. If they are invoked at the
8217 ** same time as another thread is invoking sqlite3_backup_step() it is
8218 ** possible that they return invalid values.
8220 SQLITE_API sqlite3_backup *sqlite3_backup_init(
8221 sqlite3 *pDest, /* Destination database handle */
8222 const char *zDestName, /* Destination database name */
8223 sqlite3 *pSource, /* Source database handle */
8224 const char *zSourceName /* Source database name */
8226 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
8227 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
8228 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
8229 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
8232 ** CAPI3REF: Unlock Notification
8235 ** ^When running in shared-cache mode, a database operation may fail with
8236 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
8237 ** individual tables within the shared-cache cannot be obtained. See
8238 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
8239 ** ^This API may be used to register a callback that SQLite will invoke
8240 ** when the connection currently holding the required lock relinquishes it.
8241 ** ^This API is only available if the library was compiled with the
8242 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
8244 ** See Also: [Using the SQLite Unlock Notification Feature].
8246 ** ^Shared-cache locks are released when a database connection concludes
8247 ** its current transaction, either by committing it or rolling it back.
8249 ** ^When a connection (known as the blocked connection) fails to obtain a
8250 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
8251 ** identity of the database connection (the blocking connection) that
8252 ** has locked the required resource is stored internally. ^After an
8253 ** application receives an SQLITE_LOCKED error, it may call the
8254 ** sqlite3_unlock_notify() method with the blocked connection handle as
8255 ** the first argument to register for a callback that will be invoked
8256 ** when the blocking connections current transaction is concluded. ^The
8257 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
8258 ** call that concludes the blocking connections transaction.
8260 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
8261 ** there is a chance that the blocking connection will have already
8262 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
8263 ** If this happens, then the specified callback is invoked immediately,
8264 ** from within the call to sqlite3_unlock_notify().)^
8266 ** ^If the blocked connection is attempting to obtain a write-lock on a
8267 ** shared-cache table, and more than one other connection currently holds
8268 ** a read-lock on the same table, then SQLite arbitrarily selects one of
8269 ** the other connections to use as the blocking connection.
8271 ** ^(There may be at most one unlock-notify callback registered by a
8272 ** blocked connection. If sqlite3_unlock_notify() is called when the
8273 ** blocked connection already has a registered unlock-notify callback,
8274 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
8275 ** called with a NULL pointer as its second argument, then any existing
8276 ** unlock-notify callback is canceled. ^The blocked connections
8277 ** unlock-notify callback may also be canceled by closing the blocked
8278 ** connection using [sqlite3_close()].
8280 ** The unlock-notify callback is not reentrant. If an application invokes
8281 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
8282 ** crash or deadlock may be the result.
8284 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
8285 ** returns SQLITE_OK.
8287 ** <b>Callback Invocation Details</b>
8289 ** When an unlock-notify callback is registered, the application provides a
8290 ** single void* pointer that is passed to the callback when it is invoked.
8291 ** However, the signature of the callback function allows SQLite to pass
8292 ** it an array of void* context pointers. The first argument passed to
8293 ** an unlock-notify callback is a pointer to an array of void* pointers,
8294 ** and the second is the number of entries in the array.
8296 ** When a blocking connections transaction is concluded, there may be
8297 ** more than one blocked connection that has registered for an unlock-notify
8298 ** callback. ^If two or more such blocked connections have specified the
8299 ** same callback function, then instead of invoking the callback function
8300 ** multiple times, it is invoked once with the set of void* context pointers
8301 ** specified by the blocked connections bundled together into an array.
8302 ** This gives the application an opportunity to prioritize any actions
8303 ** related to the set of unblocked database connections.
8305 ** <b>Deadlock Detection</b>
8307 ** Assuming that after registering for an unlock-notify callback a
8308 ** database waits for the callback to be issued before taking any further
8309 ** action (a reasonable assumption), then using this API may cause the
8310 ** application to deadlock. For example, if connection X is waiting for
8311 ** connection Y's transaction to be concluded, and similarly connection
8312 ** Y is waiting on connection X's transaction, then neither connection
8313 ** will proceed and the system may remain deadlocked indefinitely.
8315 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
8316 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
8317 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
8318 ** unlock-notify callback is registered. The system is said to be in
8319 ** a deadlocked state if connection A has registered for an unlock-notify
8320 ** callback on the conclusion of connection B's transaction, and connection
8321 ** B has itself registered for an unlock-notify callback when connection
8322 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
8323 ** the system is also considered to be deadlocked if connection B has
8324 ** registered for an unlock-notify callback on the conclusion of connection
8325 ** C's transaction, where connection C is waiting on connection A. ^Any
8326 ** number of levels of indirection are allowed.
8328 ** <b>The "DROP TABLE" Exception</b>
8330 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
8331 ** always appropriate to call sqlite3_unlock_notify(). There is however,
8332 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
8333 ** SQLite checks if there are any currently executing SELECT statements
8334 ** that belong to the same connection. If there are, SQLITE_LOCKED is
8335 ** returned. In this case there is no "blocking connection", so invoking
8336 ** sqlite3_unlock_notify() results in the unlock-notify callback being
8337 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
8338 ** or "DROP INDEX" query, an infinite loop might be the result.
8340 ** One way around this problem is to check the extended error code returned
8341 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
8342 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
8343 ** the special "DROP TABLE/INDEX" case, the extended error code is just
8346 SQLITE_API int sqlite3_unlock_notify(
8347 sqlite3 *pBlocked, /* Waiting connection */
8348 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
8349 void *pNotifyArg /* Argument to pass to xNotify */
8354 ** CAPI3REF: String Comparison
8356 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
8357 ** and extensions to compare the contents of two buffers containing UTF-8
8358 ** strings in a case-independent fashion, using the same definition of "case
8359 ** independence" that SQLite uses internally when comparing identifiers.
8361 SQLITE_API int sqlite3_stricmp(const char *, const char *);
8362 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
8365 ** CAPI3REF: String Globbing
8367 ** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
8368 ** string X matches the [GLOB] pattern P.
8369 ** ^The definition of [GLOB] pattern matching used in
8370 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
8371 ** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function
8372 ** is case sensitive.
8374 ** Note that this routine returns zero on a match and non-zero if the strings
8375 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
8377 ** See also: [sqlite3_strlike()].
8379 SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
8382 ** CAPI3REF: String LIKE Matching
8384 ** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
8385 ** string X matches the [LIKE] pattern P with escape character E.
8386 ** ^The definition of [LIKE] pattern matching used in
8387 ** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
8388 ** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without
8389 ** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
8390 ** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
8391 ** insensitive - equivalent upper and lower case ASCII characters match
8394 ** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
8395 ** only ASCII characters are case folded.
8397 ** Note that this routine returns zero on a match and non-zero if the strings
8398 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
8400 ** See also: [sqlite3_strglob()].
8402 SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
8405 ** CAPI3REF: Error Logging Interface
8407 ** ^The [sqlite3_log()] interface writes a message into the [error log]
8408 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
8409 ** ^If logging is enabled, the zFormat string and subsequent arguments are
8410 ** used with [sqlite3_snprintf()] to generate the final output string.
8412 ** The sqlite3_log() interface is intended for use by extensions such as
8413 ** virtual tables, collating functions, and SQL functions. While there is
8414 ** nothing to prevent an application from calling sqlite3_log(), doing so
8415 ** is considered bad form.
8417 ** The zFormat string must not be NULL.
8419 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
8420 ** will not use dynamically allocated memory. The log message is stored in
8421 ** a fixed-length buffer on the stack. If the log message is longer than
8422 ** a few hundred characters, it will be truncated to the length of the
8425 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
8428 ** CAPI3REF: Write-Ahead Log Commit Hook
8431 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
8432 ** is invoked each time data is committed to a database in wal mode.
8434 ** ^(The callback is invoked by SQLite after the commit has taken place and
8435 ** the associated write-lock on the database released)^, so the implementation
8436 ** may read, write or [checkpoint] the database as required.
8438 ** ^The first parameter passed to the callback function when it is invoked
8439 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
8440 ** registering the callback. ^The second is a copy of the database handle.
8441 ** ^The third parameter is the name of the database that was written to -
8442 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
8443 ** is the number of pages currently in the write-ahead log file,
8444 ** including those that were just committed.
8446 ** The callback function should normally return [SQLITE_OK]. ^If an error
8447 ** code is returned, that error will propagate back up through the
8448 ** SQLite code base to cause the statement that provoked the callback
8449 ** to report an error, though the commit will have still occurred. If the
8450 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
8451 ** that does not correspond to any valid SQLite error code, the results
8454 ** A single database handle may have at most a single write-ahead log callback
8455 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
8456 ** previously registered write-ahead log callback. ^Note that the
8457 ** [sqlite3_wal_autocheckpoint()] interface and the
8458 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
8459 ** overwrite any prior [sqlite3_wal_hook()] settings.
8461 SQLITE_API void *sqlite3_wal_hook(
8463 int(*)(void *,sqlite3*,const char*,int),
8468 ** CAPI3REF: Configure an auto-checkpoint
8471 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
8472 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
8473 ** to automatically [checkpoint]
8474 ** after committing a transaction if there are N or
8475 ** more frames in the [write-ahead log] file. ^Passing zero or
8476 ** a negative value as the nFrame parameter disables automatic
8477 ** checkpoints entirely.
8479 ** ^The callback registered by this function replaces any existing callback
8480 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
8481 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
8482 ** configured by this function.
8484 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
8487 ** ^Checkpoints initiated by this mechanism are
8488 ** [sqlite3_wal_checkpoint_v2|PASSIVE].
8490 ** ^Every new [database connection] defaults to having the auto-checkpoint
8491 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
8492 ** pages. The use of this interface
8493 ** is only necessary if the default setting is found to be suboptimal
8494 ** for a particular application.
8496 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
8499 ** CAPI3REF: Checkpoint a database
8502 ** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
8503 ** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
8505 ** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
8506 ** [write-ahead log] for database X on [database connection] D to be
8507 ** transferred into the database file and for the write-ahead log to
8508 ** be reset. See the [checkpointing] documentation for addition
8511 ** This interface used to be the only way to cause a checkpoint to
8512 ** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
8513 ** interface was added. This interface is retained for backwards
8514 ** compatibility and as a convenience for applications that need to manually
8515 ** start a callback but which do not need the full power (and corresponding
8516 ** complication) of [sqlite3_wal_checkpoint_v2()].
8518 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
8521 ** CAPI3REF: Checkpoint a database
8524 ** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
8525 ** operation on database X of [database connection] D in mode M. Status
8526 ** information is written back into integers pointed to by L and C.)^
8527 ** ^(The M parameter must be a valid [checkpoint mode]:)^
8530 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
8531 ** ^Checkpoint as many frames as possible without waiting for any database
8532 ** readers or writers to finish, then sync the database file if all frames
8533 ** in the log were checkpointed. ^The [busy-handler callback]
8534 ** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
8535 ** ^On the other hand, passive mode might leave the checkpoint unfinished
8536 ** if there are concurrent readers or writers.
8538 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
8539 ** ^This mode blocks (it invokes the
8540 ** [sqlite3_busy_handler|busy-handler callback]) until there is no
8541 ** database writer and all readers are reading from the most recent database
8542 ** snapshot. ^It then checkpoints all frames in the log file and syncs the
8543 ** database file. ^This mode blocks new database writers while it is pending,
8544 ** but new database readers are allowed to continue unimpeded.
8546 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
8547 ** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
8548 ** that after checkpointing the log file it blocks (calls the
8549 ** [busy-handler callback])
8550 ** until all readers are reading from the database file only. ^This ensures
8551 ** that the next writer will restart the log file from the beginning.
8552 ** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
8553 ** database writer attempts while it is pending, but does not impede readers.
8555 ** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
8556 ** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
8557 ** addition that it also truncates the log file to zero bytes just prior
8558 ** to a successful return.
8561 ** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
8562 ** the log file or to -1 if the checkpoint could not run because
8563 ** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
8564 ** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
8565 ** log file (including any that were already checkpointed before the function
8566 ** was called) or to -1 if the checkpoint could not run due to an error or
8567 ** because the database is not in WAL mode. ^Note that upon successful
8568 ** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
8569 ** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
8571 ** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
8572 ** any other process is running a checkpoint operation at the same time, the
8573 ** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
8574 ** busy-handler configured, it will not be invoked in this case.
8576 ** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
8577 ** exclusive "writer" lock on the database file. ^If the writer lock cannot be
8578 ** obtained immediately, and a busy-handler is configured, it is invoked and
8579 ** the writer lock retried until either the busy-handler returns 0 or the lock
8580 ** is successfully obtained. ^The busy-handler is also invoked while waiting for
8581 ** database readers as described above. ^If the busy-handler returns 0 before
8582 ** the writer lock is obtained or while waiting for database readers, the
8583 ** checkpoint operation proceeds from that point in the same way as
8584 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
8585 ** without blocking any further. ^SQLITE_BUSY is returned in this case.
8587 ** ^If parameter zDb is NULL or points to a zero length string, then the
8588 ** specified operation is attempted on all WAL databases [attached] to
8589 ** [database connection] db. In this case the
8590 ** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
8591 ** an SQLITE_BUSY error is encountered when processing one or more of the
8592 ** attached WAL databases, the operation is still attempted on any remaining
8593 ** attached databases and SQLITE_BUSY is returned at the end. ^If any other
8594 ** error occurs while processing an attached database, processing is abandoned
8595 ** and the error code is returned to the caller immediately. ^If no error
8596 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
8597 ** databases, SQLITE_OK is returned.
8599 ** ^If database zDb is the name of an attached database that is not in WAL
8600 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
8601 ** zDb is not NULL (or a zero length string) and is not the name of any
8602 ** attached database, SQLITE_ERROR is returned to the caller.
8604 ** ^Unless it returns SQLITE_MISUSE,
8605 ** the sqlite3_wal_checkpoint_v2() interface
8606 ** sets the error information that is queried by
8607 ** [sqlite3_errcode()] and [sqlite3_errmsg()].
8609 ** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
8612 SQLITE_API int sqlite3_wal_checkpoint_v2(
8613 sqlite3 *db, /* Database handle */
8614 const char *zDb, /* Name of attached database (or NULL) */
8615 int eMode, /* SQLITE_CHECKPOINT_* value */
8616 int *pnLog, /* OUT: Size of WAL log in frames */
8617 int *pnCkpt /* OUT: Total number of frames checkpointed */
8621 ** CAPI3REF: Checkpoint Mode Values
8622 ** KEYWORDS: {checkpoint mode}
8624 ** These constants define all valid values for the "checkpoint mode" passed
8625 ** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
8626 ** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
8627 ** meaning of each of these checkpoint modes.
8629 #define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */
8630 #define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */
8631 #define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */
8632 #define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */
8635 ** CAPI3REF: Virtual Table Interface Configuration
8637 ** This function may be called by either the [xConnect] or [xCreate] method
8638 ** of a [virtual table] implementation to configure
8639 ** various facets of the virtual table interface.
8641 ** If this interface is invoked outside the context of an xConnect or
8642 ** xCreate virtual table method then the behavior is undefined.
8644 ** At present, there is only one option that may be configured using
8645 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options
8646 ** may be added in the future.
8648 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
8651 ** CAPI3REF: Virtual Table Configuration Options
8653 ** These macros define the various options to the
8654 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
8655 ** can use to customize and optimize their behavior.
8658 ** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]]
8659 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
8660 ** <dd>Calls of the form
8661 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
8662 ** where X is an integer. If X is zero, then the [virtual table] whose
8663 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
8664 ** support constraints. In this configuration (which is the default) if
8665 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
8666 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
8667 ** specified as part of the users SQL statement, regardless of the actual
8668 ** ON CONFLICT mode specified.
8670 ** If X is non-zero, then the virtual table implementation guarantees
8671 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
8672 ** any modifications to internal or persistent data structures have been made.
8673 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
8674 ** is able to roll back a statement or database transaction, and abandon
8675 ** or continue processing the current SQL statement as appropriate.
8676 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
8677 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
8680 ** Virtual table implementations that are required to handle OR REPLACE
8681 ** must do so within the [xUpdate] method. If a call to the
8682 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
8683 ** CONFLICT policy is REPLACE, the virtual table implementation should
8684 ** silently replace the appropriate rows within the xUpdate callback and
8685 ** return SQLITE_OK. Or, if this is not possible, it may return
8686 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
8687 ** constraint handling.
8690 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
8693 ** CAPI3REF: Determine The Virtual Table Conflict Policy
8695 ** This function may only be called from within a call to the [xUpdate] method
8696 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
8697 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
8698 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
8699 ** of the SQL statement that triggered the call to the [xUpdate] method of the
8702 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
8705 ** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
8707 ** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
8708 ** method of a [virtual table], then it returns true if and only if the
8709 ** column is being fetched as part of an UPDATE operation during which the
8710 ** column value will not change. Applications might use this to substitute
8711 ** a return value that is less expensive to compute and that the corresponding
8712 ** [xUpdate] method understands as a "no-change" value.
8714 ** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
8715 ** the column is not changed by the UPDATE statement, then the xColumn
8716 ** method can optionally return without setting a result, without calling
8717 ** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
8718 ** In that case, [sqlite3_value_nochange(X)] will return true for the
8719 ** same column in the [xUpdate] method.
8721 SQLITE_API int sqlite3_vtab_nochange(sqlite3_context*);
8724 ** CAPI3REF: Determine The Collation For a Virtual Table Constraint
8726 ** This function may only be called from within a call to the [xBestIndex]
8727 ** method of a [virtual table].
8729 ** The first argument must be the sqlite3_index_info object that is the
8730 ** first parameter to the xBestIndex() method. The second argument must be
8731 ** an index into the aConstraint[] array belonging to the sqlite3_index_info
8732 ** structure passed to xBestIndex. This function returns a pointer to a buffer
8733 ** containing the name of the collation sequence for the corresponding
8736 SQLITE_API SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
8739 ** CAPI3REF: Conflict resolution modes
8740 ** KEYWORDS: {conflict resolution mode}
8742 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
8743 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
8744 ** is for the SQL statement being evaluated.
8746 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
8747 ** return value from the [sqlite3_set_authorizer()] callback and that
8748 ** [SQLITE_ABORT] is also a [result code].
8750 #define SQLITE_ROLLBACK 1
8751 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
8752 #define SQLITE_FAIL 3
8753 /* #define SQLITE_ABORT 4 // Also an error code */
8754 #define SQLITE_REPLACE 5
8757 ** CAPI3REF: Prepared Statement Scan Status Opcodes
8758 ** KEYWORDS: {scanstatus options}
8760 ** The following constants can be used for the T parameter to the
8761 ** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a
8762 ** different metric for sqlite3_stmt_scanstatus() to return.
8764 ** When the value returned to V is a string, space to hold that string is
8765 ** managed by the prepared statement S and will be automatically freed when
8769 ** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
8770 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be
8771 ** set to the total number of times that the X-th loop has run.</dd>
8773 ** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
8774 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set
8775 ** to the total number of rows examined by all iterations of the X-th loop.</dd>
8777 ** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
8778 ** <dd>^The "double" variable pointed to by the T parameter will be set to the
8779 ** query planner's estimate for the average number of rows output from each
8780 ** iteration of the X-th loop. If the query planner's estimates was accurate,
8781 ** then this value will approximate the quotient NVISIT/NLOOP and the
8782 ** product of this value for all prior loops with the same SELECTID will
8783 ** be the NLOOP value for the current loop.
8785 ** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
8786 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
8787 ** to a zero-terminated UTF-8 string containing the name of the index or table
8788 ** used for the X-th loop.
8790 ** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
8791 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
8792 ** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
8793 ** description for the X-th loop.
8795 ** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
8796 ** <dd>^The "int" variable pointed to by the T parameter will be set to the
8797 ** "select-id" for the X-th loop. The select-id identifies which query or
8798 ** subquery the loop is part of. The main query has a select-id of zero.
8799 ** The select-id is the same value as is output in the first column
8800 ** of an [EXPLAIN QUERY PLAN] query.
8803 #define SQLITE_SCANSTAT_NLOOP 0
8804 #define SQLITE_SCANSTAT_NVISIT 1
8805 #define SQLITE_SCANSTAT_EST 2
8806 #define SQLITE_SCANSTAT_NAME 3
8807 #define SQLITE_SCANSTAT_EXPLAIN 4
8808 #define SQLITE_SCANSTAT_SELECTID 5
8811 ** CAPI3REF: Prepared Statement Scan Status
8812 ** METHOD: sqlite3_stmt
8814 ** This interface returns information about the predicted and measured
8815 ** performance for pStmt. Advanced applications can use this
8816 ** interface to compare the predicted and the measured performance and
8817 ** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
8819 ** Since this interface is expected to be rarely used, it is only
8820 ** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
8821 ** compile-time option.
8823 ** The "iScanStatusOp" parameter determines which status information to return.
8824 ** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
8825 ** of this interface is undefined.
8826 ** ^The requested measurement is written into a variable pointed to by
8827 ** the "pOut" parameter.
8828 ** Parameter "idx" identifies the specific loop to retrieve statistics for.
8829 ** Loops are numbered starting from zero. ^If idx is out of range - less than
8830 ** zero or greater than or equal to the total number of loops used to implement
8831 ** the statement - a non-zero value is returned and the variable that pOut
8832 ** points to is unchanged.
8834 ** ^Statistics might not be available for all loops in all statements. ^In cases
8835 ** where there exist loops with no available statistics, this function behaves
8836 ** as if the loop did not exist - it returns non-zero and leave the variable
8837 ** that pOut points to unchanged.
8839 ** See also: [sqlite3_stmt_scanstatus_reset()]
8841 SQLITE_API int sqlite3_stmt_scanstatus(
8842 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */
8843 int idx, /* Index of loop to report on */
8844 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */
8845 void *pOut /* Result written here */
8849 ** CAPI3REF: Zero Scan-Status Counters
8850 ** METHOD: sqlite3_stmt
8852 ** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
8854 ** This API is only available if the library is built with pre-processor
8855 ** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
8857 SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
8860 ** CAPI3REF: Flush caches to disk mid-transaction
8862 ** ^If a write-transaction is open on [database connection] D when the
8863 ** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
8864 ** pages in the pager-cache that are not currently in use are written out
8865 ** to disk. A dirty page may be in use if a database cursor created by an
8866 ** active SQL statement is reading from it, or if it is page 1 of a database
8867 ** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)]
8868 ** interface flushes caches for all schemas - "main", "temp", and
8869 ** any [attached] databases.
8871 ** ^If this function needs to obtain extra database locks before dirty pages
8872 ** can be flushed to disk, it does so. ^If those locks cannot be obtained
8873 ** immediately and there is a busy-handler callback configured, it is invoked
8874 ** in the usual manner. ^If the required lock still cannot be obtained, then
8875 ** the database is skipped and an attempt made to flush any dirty pages
8876 ** belonging to the next (if any) database. ^If any databases are skipped
8877 ** because locks cannot be obtained, but no other error occurs, this
8878 ** function returns SQLITE_BUSY.
8880 ** ^If any other error occurs while flushing dirty pages to disk (for
8881 ** example an IO error or out-of-memory condition), then processing is
8882 ** abandoned and an SQLite [error code] is returned to the caller immediately.
8884 ** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
8886 ** ^This function does not set the database handle error code or message
8887 ** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
8889 SQLITE_API int sqlite3_db_cacheflush(sqlite3*);
8892 ** CAPI3REF: The pre-update hook.
8894 ** ^These interfaces are only available if SQLite is compiled using the
8895 ** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
8897 ** ^The [sqlite3_preupdate_hook()] interface registers a callback function
8898 ** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
8899 ** on a database table.
8900 ** ^At most one preupdate hook may be registered at a time on a single
8901 ** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
8902 ** the previous setting.
8903 ** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
8904 ** with a NULL pointer as the second parameter.
8905 ** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
8906 ** the first parameter to callbacks.
8908 ** ^The preupdate hook only fires for changes to real database tables; the
8909 ** preupdate hook is not invoked for changes to [virtual tables] or to
8910 ** system tables like sqlite_master or sqlite_stat1.
8912 ** ^The second parameter to the preupdate callback is a pointer to
8913 ** the [database connection] that registered the preupdate hook.
8914 ** ^The third parameter to the preupdate callback is one of the constants
8915 ** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
8916 ** kind of update operation that is about to occur.
8917 ** ^(The fourth parameter to the preupdate callback is the name of the
8918 ** database within the database connection that is being modified. This
8919 ** will be "main" for the main database or "temp" for TEMP tables or
8920 ** the name given after the AS keyword in the [ATTACH] statement for attached
8922 ** ^The fifth parameter to the preupdate callback is the name of the
8923 ** table that is being modified.
8925 ** For an UPDATE or DELETE operation on a [rowid table], the sixth
8926 ** parameter passed to the preupdate callback is the initial [rowid] of the
8927 ** row being modified or deleted. For an INSERT operation on a rowid table,
8928 ** or any operation on a WITHOUT ROWID table, the value of the sixth
8929 ** parameter is undefined. For an INSERT or UPDATE on a rowid table the
8930 ** seventh parameter is the final rowid value of the row being inserted
8931 ** or updated. The value of the seventh parameter passed to the callback
8932 ** function is not defined for operations on WITHOUT ROWID tables, or for
8933 ** INSERT operations on rowid tables.
8935 ** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
8936 ** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
8937 ** provide additional information about a preupdate event. These routines
8938 ** may only be called from within a preupdate callback. Invoking any of
8939 ** these routines from outside of a preupdate callback or with a
8940 ** [database connection] pointer that is different from the one supplied
8941 ** to the preupdate callback results in undefined and probably undesirable
8944 ** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
8945 ** in the row that is being inserted, updated, or deleted.
8947 ** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
8948 ** a [protected sqlite3_value] that contains the value of the Nth column of
8949 ** the table row before it is updated. The N parameter must be between 0
8950 ** and one less than the number of columns or the behavior will be
8951 ** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
8952 ** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
8953 ** behavior is undefined. The [sqlite3_value] that P points to
8954 ** will be destroyed when the preupdate callback returns.
8956 ** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
8957 ** a [protected sqlite3_value] that contains the value of the Nth column of
8958 ** the table row after it is updated. The N parameter must be between 0
8959 ** and one less than the number of columns or the behavior will be
8960 ** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
8961 ** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
8962 ** behavior is undefined. The [sqlite3_value] that P points to
8963 ** will be destroyed when the preupdate callback returns.
8965 ** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
8966 ** callback was invoked as a result of a direct insert, update, or delete
8967 ** operation; or 1 for inserts, updates, or deletes invoked by top-level
8968 ** triggers; or 2 for changes resulting from triggers called by top-level
8969 ** triggers; and so forth.
8971 ** See also: [sqlite3_update_hook()]
8973 #if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
8974 SQLITE_API void *sqlite3_preupdate_hook(
8977 void *pCtx, /* Copy of third arg to preupdate_hook() */
8978 sqlite3 *db, /* Database handle */
8979 int op, /* SQLITE_UPDATE, DELETE or INSERT */
8980 char const *zDb, /* Database name */
8981 char const *zName, /* Table name */
8982 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */
8983 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */
8987 SQLITE_API int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
8988 SQLITE_API int sqlite3_preupdate_count(sqlite3 *);
8989 SQLITE_API int sqlite3_preupdate_depth(sqlite3 *);
8990 SQLITE_API int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
8994 ** CAPI3REF: Low-level system error code
8996 ** ^Attempt to return the underlying operating system error code or error
8997 ** number that caused the most recent I/O error or failure to open a file.
8998 ** The return value is OS-dependent. For example, on unix systems, after
8999 ** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
9000 ** called to get back the underlying "errno" that caused the problem, such
9001 ** as ENOSPC, EAUTH, EISDIR, and so forth.
9003 SQLITE_API int sqlite3_system_errno(sqlite3*);
9006 ** CAPI3REF: Database Snapshot
9007 ** KEYWORDS: {snapshot} {sqlite3_snapshot}
9009 ** An instance of the snapshot object records the state of a [WAL mode]
9010 ** database for some specific point in history.
9012 ** In [WAL mode], multiple [database connections] that are open on the
9013 ** same database file can each be reading a different historical version
9014 ** of the database file. When a [database connection] begins a read
9015 ** transaction, that connection sees an unchanging copy of the database
9016 ** as it existed for the point in time when the transaction first started.
9017 ** Subsequent changes to the database from other connections are not seen
9018 ** by the reader until a new read transaction is started.
9020 ** The sqlite3_snapshot object records state information about an historical
9021 ** version of the database file so that it is possible to later open a new read
9022 ** transaction that sees that historical version of the database rather than
9023 ** the most recent version.
9025 typedef struct sqlite3_snapshot {
9026 unsigned char hidden[48];
9030 ** CAPI3REF: Record A Database Snapshot
9031 ** CONSTRUCTOR: sqlite3_snapshot
9033 ** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
9034 ** new [sqlite3_snapshot] object that records the current state of
9035 ** schema S in database connection D. ^On success, the
9036 ** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
9037 ** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
9038 ** If there is not already a read-transaction open on schema S when
9039 ** this function is called, one is opened automatically.
9041 ** The following must be true for this function to succeed. If any of
9042 ** the following statements are false when sqlite3_snapshot_get() is
9043 ** called, SQLITE_ERROR is returned. The final value of *P is undefined
9047 ** <li> The database handle must not be in [autocommit mode].
9049 ** <li> Schema S of [database connection] D must be a [WAL mode] database.
9051 ** <li> There must not be a write transaction open on schema S of database
9054 ** <li> One or more transactions must have been written to the current wal
9055 ** file since it was created on disk (by any connection). This means
9056 ** that a snapshot cannot be taken on a wal mode database with no wal
9057 ** file immediately after it is first opened. At least one transaction
9058 ** must be written to it first.
9061 ** This function may also return SQLITE_NOMEM. If it is called with the
9062 ** database handle in autocommit mode but fails for some other reason,
9063 ** whether or not a read transaction is opened on schema S is undefined.
9065 ** The [sqlite3_snapshot] object returned from a successful call to
9066 ** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
9067 ** to avoid a memory leak.
9069 ** The [sqlite3_snapshot_get()] interface is only available when the
9070 ** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
9072 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
9074 const char *zSchema,
9075 sqlite3_snapshot **ppSnapshot
9079 ** CAPI3REF: Start a read transaction on an historical snapshot
9080 ** METHOD: sqlite3_snapshot
9082 ** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read
9083 ** transaction or upgrades an existing one for schema S of
9084 ** [database connection] D such that the read transaction refers to
9085 ** historical [snapshot] P, rather than the most recent change to the
9086 ** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK
9087 ** on success or an appropriate [error code] if it fails.
9089 ** ^In order to succeed, the database connection must not be in
9090 ** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there
9091 ** is already a read transaction open on schema S, then the database handle
9092 ** must have no active statements (SELECT statements that have been passed
9093 ** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()).
9094 ** SQLITE_ERROR is returned if either of these conditions is violated, or
9095 ** if schema S does not exist, or if the snapshot object is invalid.
9097 ** ^A call to sqlite3_snapshot_open() will fail to open if the specified
9098 ** snapshot has been overwritten by a [checkpoint]. In this case
9099 ** SQLITE_ERROR_SNAPSHOT is returned.
9101 ** If there is already a read transaction open when this function is
9102 ** invoked, then the same read transaction remains open (on the same
9103 ** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT
9104 ** is returned. If another error code - for example SQLITE_PROTOCOL or an
9105 ** SQLITE_IOERR error code - is returned, then the final state of the
9106 ** read transaction is undefined. If SQLITE_OK is returned, then the
9107 ** read transaction is now open on database snapshot P.
9109 ** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
9110 ** database connection D does not know that the database file for
9111 ** schema S is in [WAL mode]. A database connection might not know
9112 ** that the database file is in [WAL mode] if there has been no prior
9113 ** I/O on that database connection, or if the database entered [WAL mode]
9114 ** after the most recent I/O on the database connection.)^
9115 ** (Hint: Run "[PRAGMA application_id]" against a newly opened
9116 ** database connection in order to make it ready to use snapshots.)
9118 ** The [sqlite3_snapshot_open()] interface is only available when the
9119 ** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
9121 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
9123 const char *zSchema,
9124 sqlite3_snapshot *pSnapshot
9128 ** CAPI3REF: Destroy a snapshot
9129 ** DESTRUCTOR: sqlite3_snapshot
9131 ** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
9132 ** The application must eventually free every [sqlite3_snapshot] object
9133 ** using this routine to avoid a memory leak.
9135 ** The [sqlite3_snapshot_free()] interface is only available when the
9136 ** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
9138 SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
9141 ** CAPI3REF: Compare the ages of two snapshot handles.
9142 ** METHOD: sqlite3_snapshot
9144 ** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
9145 ** of two valid snapshot handles.
9147 ** If the two snapshot handles are not associated with the same database
9148 ** file, the result of the comparison is undefined.
9150 ** Additionally, the result of the comparison is only valid if both of the
9151 ** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
9152 ** last time the wal file was deleted. The wal file is deleted when the
9153 ** database is changed back to rollback mode or when the number of database
9154 ** clients drops to zero. If either snapshot handle was obtained before the
9155 ** wal file was last deleted, the value returned by this function
9158 ** Otherwise, this API returns a negative value if P1 refers to an older
9159 ** snapshot than P2, zero if the two handles refer to the same database
9160 ** snapshot, and a positive value if P1 is a newer snapshot than P2.
9162 ** This interface is only available if SQLite is compiled with the
9163 ** [SQLITE_ENABLE_SNAPSHOT] option.
9165 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
9166 sqlite3_snapshot *p1,
9167 sqlite3_snapshot *p2
9171 ** CAPI3REF: Recover snapshots from a wal file
9172 ** METHOD: sqlite3_snapshot
9174 ** If a [WAL file] remains on disk after all database connections close
9175 ** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control]
9176 ** or because the last process to have the database opened exited without
9177 ** calling [sqlite3_close()]) and a new connection is subsequently opened
9178 ** on that database and [WAL file], the [sqlite3_snapshot_open()] interface
9179 ** will only be able to open the last transaction added to the WAL file
9180 ** even though the WAL file contains other valid transactions.
9182 ** This function attempts to scan the WAL file associated with database zDb
9183 ** of database handle db and make all valid snapshots available to
9184 ** sqlite3_snapshot_open(). It is an error if there is already a read
9185 ** transaction open on the database, or if the database is not a WAL mode
9188 ** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
9190 ** This interface is only available if SQLite is compiled with the
9191 ** [SQLITE_ENABLE_SNAPSHOT] option.
9193 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
9196 ** CAPI3REF: Serialize a database
9198 ** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory
9199 ** that is a serialization of the S database on [database connection] D.
9200 ** If P is not a NULL pointer, then the size of the database in bytes
9201 ** is written into *P.
9203 ** For an ordinary on-disk database file, the serialization is just a
9204 ** copy of the disk file. For an in-memory database or a "TEMP" database,
9205 ** the serialization is the same sequence of bytes which would be written
9206 ** to disk if that database where backed up to disk.
9208 ** The usual case is that sqlite3_serialize() copies the serialization of
9209 ** the database into memory obtained from [sqlite3_malloc64()] and returns
9210 ** a pointer to that memory. The caller is responsible for freeing the
9211 ** returned value to avoid a memory leak. However, if the F argument
9212 ** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
9213 ** are made, and the sqlite3_serialize() function will return a pointer
9214 ** to the contiguous memory representation of the database that SQLite
9215 ** is currently using for that database, or NULL if the no such contiguous
9216 ** memory representation of the database exists. A contiguous memory
9217 ** representation of the database will usually only exist if there has
9218 ** been a prior call to [sqlite3_deserialize(D,S,...)] with the same
9219 ** values of D and S.
9220 ** The size of the database is written into *P even if the
9221 ** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
9222 ** of the database exists.
9224 ** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
9225 ** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
9226 ** allocation error occurs.
9228 ** This interface is only available if SQLite is compiled with the
9229 ** [SQLITE_ENABLE_DESERIALIZE] option.
9231 SQLITE_API unsigned char *sqlite3_serialize(
9232 sqlite3 *db, /* The database connection */
9233 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */
9234 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */
9235 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */
9239 ** CAPI3REF: Flags for sqlite3_serialize
9241 ** Zero or more of the following constants can be OR-ed together for
9242 ** the F argument to [sqlite3_serialize(D,S,P,F)].
9244 ** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return
9245 ** a pointer to contiguous in-memory database that it is currently using,
9246 ** without making a copy of the database. If SQLite is not currently using
9247 ** a contiguous in-memory database, then this option causes
9248 ** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be
9249 ** using a contiguous in-memory database if it has been initialized by a
9250 ** prior call to [sqlite3_deserialize()].
9252 #define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */
9255 ** CAPI3REF: Deserialize a database
9257 ** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
9258 ** [database connection] D to disconnect from database S and then
9259 ** reopen S as an in-memory database based on the serialization contained
9260 ** in P. The serialized database P is N bytes in size. M is the size of
9261 ** the buffer P, which might be larger than N. If M is larger than N, and
9262 ** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
9263 ** permitted to add content to the in-memory database as long as the total
9264 ** size does not exceed M bytes.
9266 ** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
9267 ** invoke sqlite3_free() on the serialization buffer when the database
9268 ** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
9269 ** SQLite will try to increase the buffer size using sqlite3_realloc64()
9270 ** if writes on the database cause it to grow larger than M bytes.
9272 ** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
9273 ** database is currently in a read transaction or is involved in a backup
9276 ** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
9277 ** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
9278 ** [sqlite3_free()] is invoked on argument P prior to returning.
9280 ** This interface is only available if SQLite is compiled with the
9281 ** [SQLITE_ENABLE_DESERIALIZE] option.
9283 SQLITE_API int sqlite3_deserialize(
9284 sqlite3 *db, /* The database connection */
9285 const char *zSchema, /* Which DB to reopen with the deserialization */
9286 unsigned char *pData, /* The serialized database content */
9287 sqlite3_int64 szDb, /* Number bytes in the deserialization */
9288 sqlite3_int64 szBuf, /* Total size of buffer pData[] */
9289 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */
9293 ** CAPI3REF: Flags for sqlite3_deserialize()
9295 ** The following are allowed values for 6th argument (the F argument) to
9296 ** the [sqlite3_deserialize(D,S,P,N,M,F)] interface.
9298 ** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
9299 ** in the P argument is held in memory obtained from [sqlite3_malloc64()]
9300 ** and that SQLite should take ownership of this memory and automatically
9301 ** free it when it has finished using it. Without this flag, the caller
9302 ** is responsible for freeing any dynamically allocated memory.
9304 ** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
9305 ** grow the size of the database using calls to [sqlite3_realloc64()]. This
9306 ** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
9307 ** Without this flag, the deserialized database cannot increase in size beyond
9308 ** the number of bytes specified by the M parameter.
9310 ** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
9311 ** should be treated as read-only.
9313 #define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
9314 #define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */
9315 #define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */
9318 ** Undo the hack that converts floating point types to integer for
9319 ** builds on processors without floating point support.
9321 #ifdef SQLITE_OMIT_FLOATING_POINT
9326 } /* End of the 'extern "C"' block */
9328 #endif /* SQLITE3_H */
9330 /******** Begin file sqlite3rtree.h *********/
9334 ** The author disclaims copyright to this source code. In place of
9335 ** a legal notice, here is a blessing:
9337 ** May you do good and not evil.
9338 ** May you find forgiveness for yourself and forgive others.
9339 ** May you share freely, never taking more than you give.
9341 *************************************************************************
9344 #ifndef _SQLITE3RTREE_H_
9345 #define _SQLITE3RTREE_H_
9352 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
9353 typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
9355 /* The double-precision datatype used by RTree depends on the
9356 ** SQLITE_RTREE_INT_ONLY compile-time option.
9358 #ifdef SQLITE_RTREE_INT_ONLY
9359 typedef sqlite3_int64 sqlite3_rtree_dbl;
9361 typedef double sqlite3_rtree_dbl;
9365 ** Register a geometry callback named zGeom that can be used as part of an
9366 ** R-Tree geometry query as follows:
9368 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
9370 SQLITE_API int sqlite3_rtree_geometry_callback(
9373 int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
9379 ** A pointer to a structure of the following type is passed as the first
9380 ** argument to callbacks registered using rtree_geometry_callback().
9382 struct sqlite3_rtree_geometry {
9383 void *pContext; /* Copy of pContext passed to s_r_g_c() */
9384 int nParam; /* Size of array aParam[] */
9385 sqlite3_rtree_dbl *aParam; /* Parameters passed to SQL geom function */
9386 void *pUser; /* Callback implementation user data */
9387 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */
9391 ** Register a 2nd-generation geometry callback named zScore that can be
9392 ** used as part of an R-Tree geometry query as follows:
9394 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
9396 SQLITE_API int sqlite3_rtree_query_callback(
9398 const char *zQueryFunc,
9399 int (*xQueryFunc)(sqlite3_rtree_query_info*),
9401 void (*xDestructor)(void*)
9406 ** A pointer to a structure of the following type is passed as the
9407 ** argument to scored geometry callback registered using
9408 ** sqlite3_rtree_query_callback().
9410 ** Note that the first 5 fields of this structure are identical to
9411 ** sqlite3_rtree_geometry. This structure is a subclass of
9412 ** sqlite3_rtree_geometry.
9414 struct sqlite3_rtree_query_info {
9415 void *pContext; /* pContext from when function registered */
9416 int nParam; /* Number of function parameters */
9417 sqlite3_rtree_dbl *aParam; /* value of function parameters */
9418 void *pUser; /* callback can use this, if desired */
9419 void (*xDelUser)(void*); /* function to free pUser */
9420 sqlite3_rtree_dbl *aCoord; /* Coordinates of node or entry to check */
9421 unsigned int *anQueue; /* Number of pending entries in the queue */
9422 int nCoord; /* Number of coordinates */
9423 int iLevel; /* Level of current node or entry */
9424 int mxLevel; /* The largest iLevel value in the tree */
9425 sqlite3_int64 iRowid; /* Rowid for current entry */
9426 sqlite3_rtree_dbl rParentScore; /* Score of parent node */
9427 int eParentWithin; /* Visibility of parent node */
9428 int eWithin; /* OUT: Visibility */
9429 sqlite3_rtree_dbl rScore; /* OUT: Write the score here */
9430 /* The following fields are only available in 3.8.11 and later */
9431 sqlite3_value **apSqlParam; /* Original SQL values of parameters */
9435 ** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
9437 #define NOT_WITHIN 0 /* Object completely outside of query region */
9438 #define PARTLY_WITHIN 1 /* Object partially overlaps query region */
9439 #define FULLY_WITHIN 2 /* Object fully contained within query region */
9443 } /* end of the 'extern "C"' block */
9446 #endif /* ifndef _SQLITE3RTREE_H_ */
9448 /******** End of sqlite3rtree.h *********/
9449 /******** Begin file sqlite3session.h *********/
9451 #if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
9452 #define __SQLITESESSION_H_ 1
9455 ** Make sure we can call this stuff from C++.
9463 ** CAPI3REF: Session Object Handle
9465 ** An instance of this object is a [session] that can be used to
9466 ** record changes to a database.
9468 typedef struct sqlite3_session sqlite3_session;
9471 ** CAPI3REF: Changeset Iterator Handle
9473 ** An instance of this object acts as a cursor for iterating
9474 ** over the elements of a [changeset] or [patchset].
9476 typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
9479 ** CAPI3REF: Create A New Session Object
9480 ** CONSTRUCTOR: sqlite3_session
9482 ** Create a new session object attached to database handle db. If successful,
9483 ** a pointer to the new object is written to *ppSession and SQLITE_OK is
9484 ** returned. If an error occurs, *ppSession is set to NULL and an SQLite
9485 ** error code (e.g. SQLITE_NOMEM) is returned.
9487 ** It is possible to create multiple session objects attached to a single
9490 ** Session objects created using this function should be deleted using the
9491 ** [sqlite3session_delete()] function before the database handle that they
9492 ** are attached to is itself closed. If the database handle is closed before
9493 ** the session object is deleted, then the results of calling any session
9494 ** module function, including [sqlite3session_delete()] on the session object
9497 ** Because the session module uses the [sqlite3_preupdate_hook()] API, it
9498 ** is not possible for an application to register a pre-update hook on a
9499 ** database handle that has one or more session objects attached. Nor is
9500 ** it possible to create a session object attached to a database handle for
9501 ** which a pre-update hook is already defined. The results of attempting
9502 ** either of these things are undefined.
9504 ** The session object will be used to create changesets for tables in
9505 ** database zDb, where zDb is either "main", or "temp", or the name of an
9506 ** attached database. It is not an error if database zDb is not attached
9507 ** to the database when the session object is created.
9509 SQLITE_API int sqlite3session_create(
9510 sqlite3 *db, /* Database handle */
9511 const char *zDb, /* Name of db (e.g. "main") */
9512 sqlite3_session **ppSession /* OUT: New session object */
9516 ** CAPI3REF: Delete A Session Object
9517 ** DESTRUCTOR: sqlite3_session
9519 ** Delete a session object previously allocated using
9520 ** [sqlite3session_create()]. Once a session object has been deleted, the
9521 ** results of attempting to use pSession with any other session module
9522 ** function are undefined.
9524 ** Session objects must be deleted before the database handle to which they
9525 ** are attached is closed. Refer to the documentation for
9526 ** [sqlite3session_create()] for details.
9528 SQLITE_API void sqlite3session_delete(sqlite3_session *pSession);
9532 ** CAPI3REF: Enable Or Disable A Session Object
9533 ** METHOD: sqlite3_session
9535 ** Enable or disable the recording of changes by a session object. When
9536 ** enabled, a session object records changes made to the database. When
9537 ** disabled - it does not. A newly created session object is enabled.
9538 ** Refer to the documentation for [sqlite3session_changeset()] for further
9539 ** details regarding how enabling and disabling a session object affects
9540 ** the eventual changesets.
9542 ** Passing zero to this function disables the session. Passing a value
9543 ** greater than zero enables it. Passing a value less than zero is a
9544 ** no-op, and may be used to query the current state of the session.
9546 ** The return value indicates the final state of the session object: 0 if
9547 ** the session is disabled, or 1 if it is enabled.
9549 SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable);
9552 ** CAPI3REF: Set Or Clear the Indirect Change Flag
9553 ** METHOD: sqlite3_session
9555 ** Each change recorded by a session object is marked as either direct or
9556 ** indirect. A change is marked as indirect if either:
9559 ** <li> The session object "indirect" flag is set when the change is
9561 ** <li> The change is made by an SQL trigger or foreign key action
9562 ** instead of directly as a result of a users SQL statement.
9565 ** If a single row is affected by more than one operation within a session,
9566 ** then the change is considered indirect if all operations meet the criteria
9567 ** for an indirect change above, or direct otherwise.
9569 ** This function is used to set, clear or query the session object indirect
9570 ** flag. If the second argument passed to this function is zero, then the
9571 ** indirect flag is cleared. If it is greater than zero, the indirect flag
9572 ** is set. Passing a value less than zero does not modify the current value
9573 ** of the indirect flag, and may be used to query the current state of the
9574 ** indirect flag for the specified session object.
9576 ** The return value indicates the final state of the indirect flag: 0 if
9577 ** it is clear, or 1 if it is set.
9579 SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect);
9582 ** CAPI3REF: Attach A Table To A Session Object
9583 ** METHOD: sqlite3_session
9585 ** If argument zTab is not NULL, then it is the name of a table to attach
9586 ** to the session object passed as the first argument. All subsequent changes
9587 ** made to the table while the session object is enabled will be recorded. See
9588 ** documentation for [sqlite3session_changeset()] for further details.
9590 ** Or, if argument zTab is NULL, then changes are recorded for all tables
9591 ** in the database. If additional tables are added to the database (by
9592 ** executing "CREATE TABLE" statements) after this call is made, changes for
9593 ** the new tables are also recorded.
9595 ** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
9596 ** defined as part of their CREATE TABLE statement. It does not matter if the
9597 ** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
9598 ** KEY may consist of a single column, or may be a composite key.
9600 ** It is not an error if the named table does not exist in the database. Nor
9601 ** is it an error if the named table does not have a PRIMARY KEY. However,
9602 ** no changes will be recorded in either of these scenarios.
9604 ** Changes are not recorded for individual rows that have NULL values stored
9605 ** in one or more of their PRIMARY KEY columns.
9607 ** SQLITE_OK is returned if the call completes without error. Or, if an error
9608 ** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
9610 ** <h3>Special sqlite_stat1 Handling</h3>
9612 ** As of SQLite version 3.22.0, the "sqlite_stat1" table is an exception to
9613 ** some of the rules above. In SQLite, the schema of sqlite_stat1 is:
9615 ** CREATE TABLE sqlite_stat1(tbl,idx,stat)
9618 ** Even though sqlite_stat1 does not have a PRIMARY KEY, changes are
9619 ** recorded for it as if the PRIMARY KEY is (tbl,idx). Additionally, changes
9620 ** are recorded for rows for which (idx IS NULL) is true. However, for such
9621 ** rows a zero-length blob (SQL value X'') is stored in the changeset or
9622 ** patchset instead of a NULL value. This allows such changesets to be
9623 ** manipulated by legacy implementations of sqlite3changeset_invert(),
9624 ** concat() and similar.
9626 ** The sqlite3changeset_apply() function automatically converts the
9627 ** zero-length blob back to a NULL value when updating the sqlite_stat1
9628 ** table. However, if the application calls sqlite3changeset_new(),
9629 ** sqlite3changeset_old() or sqlite3changeset_conflict on a changeset
9630 ** iterator directly (including on a changeset iterator passed to a
9631 ** conflict-handler callback) then the X'' value is returned. The application
9632 ** must translate X'' to NULL itself if required.
9634 ** Legacy (older than 3.22.0) versions of the sessions module cannot capture
9635 ** changes made to the sqlite_stat1 table. Legacy versions of the
9636 ** sqlite3changeset_apply() function silently ignore any modifications to the
9637 ** sqlite_stat1 table that are part of a changeset or patchset.
9639 SQLITE_API int sqlite3session_attach(
9640 sqlite3_session *pSession, /* Session object */
9641 const char *zTab /* Table name */
9645 ** CAPI3REF: Set a table filter on a Session Object.
9646 ** METHOD: sqlite3_session
9648 ** The second argument (xFilter) is the "filter callback". For changes to rows
9649 ** in tables that are not attached to the Session object, the filter is called
9650 ** to determine whether changes to the table's rows should be tracked or not.
9651 ** If xFilter returns 0, changes is not tracked. Note that once a table is
9652 ** attached, xFilter will not be called again.
9654 SQLITE_API void sqlite3session_table_filter(
9655 sqlite3_session *pSession, /* Session object */
9657 void *pCtx, /* Copy of third arg to _filter_table() */
9658 const char *zTab /* Table name */
9660 void *pCtx /* First argument passed to xFilter */
9664 ** CAPI3REF: Generate A Changeset From A Session Object
9665 ** METHOD: sqlite3_session
9667 ** Obtain a changeset containing changes to the tables attached to the
9668 ** session object passed as the first argument. If successful,
9669 ** set *ppChangeset to point to a buffer containing the changeset
9670 ** and *pnChangeset to the size of the changeset in bytes before returning
9671 ** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
9672 ** zero and return an SQLite error code.
9674 ** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
9675 ** each representing a change to a single row of an attached table. An INSERT
9676 ** change contains the values of each field of a new database row. A DELETE
9677 ** contains the original values of each field of a deleted database row. An
9678 ** UPDATE change contains the original values of each field of an updated
9679 ** database row along with the updated values for each updated non-primary-key
9680 ** column. It is not possible for an UPDATE change to represent a change that
9681 ** modifies the values of primary key columns. If such a change is made, it
9682 ** is represented in a changeset as a DELETE followed by an INSERT.
9684 ** Changes are not recorded for rows that have NULL values stored in one or
9685 ** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
9686 ** no corresponding change is present in the changesets returned by this
9687 ** function. If an existing row with one or more NULL values stored in
9688 ** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
9689 ** only an INSERT is appears in the changeset. Similarly, if an existing row
9690 ** with non-NULL PRIMARY KEY values is updated so that one or more of its
9691 ** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
9692 ** DELETE change only.
9694 ** The contents of a changeset may be traversed using an iterator created
9695 ** using the [sqlite3changeset_start()] API. A changeset may be applied to
9696 ** a database with a compatible schema using the [sqlite3changeset_apply()]
9699 ** Within a changeset generated by this function, all changes related to a
9700 ** single table are grouped together. In other words, when iterating through
9701 ** a changeset or when applying a changeset to a database, all changes related
9702 ** to a single table are processed before moving on to the next table. Tables
9703 ** are sorted in the same order in which they were attached (or auto-attached)
9704 ** to the sqlite3_session object. The order in which the changes related to
9705 ** a single table are stored is undefined.
9707 ** Following a successful call to this function, it is the responsibility of
9708 ** the caller to eventually free the buffer that *ppChangeset points to using
9709 ** [sqlite3_free()].
9711 ** <h3>Changeset Generation</h3>
9713 ** Once a table has been attached to a session object, the session object
9714 ** records the primary key values of all new rows inserted into the table.
9715 ** It also records the original primary key and other column values of any
9716 ** deleted or updated rows. For each unique primary key value, data is only
9717 ** recorded once - the first time a row with said primary key is inserted,
9718 ** updated or deleted in the lifetime of the session.
9720 ** There is one exception to the previous paragraph: when a row is inserted,
9721 ** updated or deleted, if one or more of its primary key columns contain a
9722 ** NULL value, no record of the change is made.
9724 ** The session object therefore accumulates two types of records - those
9725 ** that consist of primary key values only (created when the user inserts
9726 ** a new record) and those that consist of the primary key values and the
9727 ** original values of other table columns (created when the users deletes
9728 ** or updates a record).
9730 ** When this function is called, the requested changeset is created using
9731 ** both the accumulated records and the current contents of the database
9732 ** file. Specifically:
9735 ** <li> For each record generated by an insert, the database is queried
9736 ** for a row with a matching primary key. If one is found, an INSERT
9737 ** change is added to the changeset. If no such row is found, no change
9738 ** is added to the changeset.
9740 ** <li> For each record generated by an update or delete, the database is
9741 ** queried for a row with a matching primary key. If such a row is
9742 ** found and one or more of the non-primary key fields have been
9743 ** modified from their original values, an UPDATE change is added to
9744 ** the changeset. Or, if no such row is found in the table, a DELETE
9745 ** change is added to the changeset. If there is a row with a matching
9746 ** primary key in the database, but all fields contain their original
9747 ** values, no change is added to the changeset.
9750 ** This means, amongst other things, that if a row is inserted and then later
9751 ** deleted while a session object is active, neither the insert nor the delete
9752 ** will be present in the changeset. Or if a row is deleted and then later a
9753 ** row with the same primary key values inserted while a session object is
9754 ** active, the resulting changeset will contain an UPDATE change instead of
9755 ** a DELETE and an INSERT.
9757 ** When a session object is disabled (see the [sqlite3session_enable()] API),
9758 ** it does not accumulate records when rows are inserted, updated or deleted.
9759 ** This may appear to have some counter-intuitive effects if a single row
9760 ** is written to more than once during a session. For example, if a row
9761 ** is inserted while a session object is enabled, then later deleted while
9762 ** the same session object is disabled, no INSERT record will appear in the
9763 ** changeset, even though the delete took place while the session was disabled.
9764 ** Or, if one field of a row is updated while a session is disabled, and
9765 ** another field of the same row is updated while the session is enabled, the
9766 ** resulting changeset will contain an UPDATE change that updates both fields.
9768 SQLITE_API int sqlite3session_changeset(
9769 sqlite3_session *pSession, /* Session object */
9770 int *pnChangeset, /* OUT: Size of buffer at *ppChangeset */
9771 void **ppChangeset /* OUT: Buffer containing changeset */
9775 ** CAPI3REF: Load The Difference Between Tables Into A Session
9776 ** METHOD: sqlite3_session
9778 ** If it is not already attached to the session object passed as the first
9779 ** argument, this function attaches table zTbl in the same manner as the
9780 ** [sqlite3session_attach()] function. If zTbl does not exist, or if it
9781 ** does not have a primary key, this function is a no-op (but does not return
9784 ** Argument zFromDb must be the name of a database ("main", "temp" etc.)
9785 ** attached to the same database handle as the session object that contains
9786 ** a table compatible with the table attached to the session by this function.
9787 ** A table is considered compatible if it:
9790 ** <li> Has the same name,
9791 ** <li> Has the same set of columns declared in the same order, and
9792 ** <li> Has the same PRIMARY KEY definition.
9795 ** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
9796 ** are compatible but do not have any PRIMARY KEY columns, it is not an error
9797 ** but no changes are added to the session object. As with other session
9798 ** APIs, tables without PRIMARY KEYs are simply ignored.
9800 ** This function adds a set of changes to the session object that could be
9801 ** used to update the table in database zFrom (call this the "from-table")
9802 ** so that its content is the same as the table attached to the session
9803 ** object (call this the "to-table"). Specifically:
9806 ** <li> For each row (primary key) that exists in the to-table but not in
9807 ** the from-table, an INSERT record is added to the session object.
9809 ** <li> For each row (primary key) that exists in the to-table but not in
9810 ** the from-table, a DELETE record is added to the session object.
9812 ** <li> For each row (primary key) that exists in both tables, but features
9813 ** different non-PK values in each, an UPDATE record is added to the
9817 ** To clarify, if this function is called and then a changeset constructed
9818 ** using [sqlite3session_changeset()], then after applying that changeset to
9819 ** database zFrom the contents of the two compatible tables would be
9822 ** It an error if database zFrom does not exist or does not contain the
9823 ** required compatible table.
9825 ** If the operation successful, SQLITE_OK is returned. Otherwise, an SQLite
9826 ** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
9827 ** may be set to point to a buffer containing an English language error
9828 ** message. It is the responsibility of the caller to free this buffer using
9831 SQLITE_API int sqlite3session_diff(
9832 sqlite3_session *pSession,
9833 const char *zFromDb,
9840 ** CAPI3REF: Generate A Patchset From A Session Object
9841 ** METHOD: sqlite3_session
9843 ** The differences between a patchset and a changeset are that:
9846 ** <li> DELETE records consist of the primary key fields only. The
9847 ** original values of other fields are omitted.
9848 ** <li> The original values of any modified fields are omitted from
9852 ** A patchset blob may be used with up to date versions of all
9853 ** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(),
9854 ** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
9855 ** attempting to use a patchset blob with old versions of the
9856 ** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error.
9858 ** Because the non-primary key "old.*" fields are omitted, no
9859 ** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
9860 ** is passed to the sqlite3changeset_apply() API. Other conflict types work
9861 ** in the same way as for changesets.
9863 ** Changes within a patchset are ordered in the same way as for changesets
9864 ** generated by the sqlite3session_changeset() function (i.e. all changes for
9865 ** a single table are grouped together, tables appear in the order in which
9866 ** they were attached to the session object).
9868 SQLITE_API int sqlite3session_patchset(
9869 sqlite3_session *pSession, /* Session object */
9870 int *pnPatchset, /* OUT: Size of buffer at *ppPatchset */
9871 void **ppPatchset /* OUT: Buffer containing patchset */
9875 ** CAPI3REF: Test if a changeset has recorded any changes.
9877 ** Return non-zero if no changes to attached tables have been recorded by
9878 ** the session object passed as the first argument. Otherwise, if one or
9879 ** more changes have been recorded, return zero.
9881 ** Even if this function returns zero, it is possible that calling
9882 ** [sqlite3session_changeset()] on the session handle may still return a
9883 ** changeset that contains no changes. This can happen when a row in
9884 ** an attached table is modified and then later on the original values
9885 ** are restored. However, if this function returns non-zero, then it is
9886 ** guaranteed that a call to sqlite3session_changeset() will return a
9887 ** changeset containing zero changes.
9889 SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);
9892 ** CAPI3REF: Create An Iterator To Traverse A Changeset
9893 ** CONSTRUCTOR: sqlite3_changeset_iter
9895 ** Create an iterator used to iterate through the contents of a changeset.
9896 ** If successful, *pp is set to point to the iterator handle and SQLITE_OK
9897 ** is returned. Otherwise, if an error occurs, *pp is set to zero and an
9898 ** SQLite error code is returned.
9900 ** The following functions can be used to advance and query a changeset
9901 ** iterator created by this function:
9904 ** <li> [sqlite3changeset_next()]
9905 ** <li> [sqlite3changeset_op()]
9906 ** <li> [sqlite3changeset_new()]
9907 ** <li> [sqlite3changeset_old()]
9910 ** It is the responsibility of the caller to eventually destroy the iterator
9911 ** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
9912 ** changeset (pChangeset) must remain valid until after the iterator is
9915 ** Assuming the changeset blob was created by one of the
9916 ** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
9917 ** [sqlite3changeset_invert()] functions, all changes within the changeset
9918 ** that apply to a single table are grouped together. This means that when
9919 ** an application iterates through a changeset using an iterator created by
9920 ** this function, all changes that relate to a single table are visited
9921 ** consecutively. There is no chance that the iterator will visit a change
9922 ** the applies to table X, then one for table Y, and then later on visit
9923 ** another change for table X.
9925 ** The behavior of sqlite3changeset_start_v2() and its streaming equivalent
9926 ** may be modified by passing a combination of
9927 ** [SQLITE_CHANGESETSTART_INVERT | supported flags] as the 4th parameter.
9929 ** Note that the sqlite3changeset_start_v2() API is still <b>experimental</b>
9930 ** and therefore subject to change.
9932 SQLITE_API int sqlite3changeset_start(
9933 sqlite3_changeset_iter **pp, /* OUT: New changeset iterator handle */
9934 int nChangeset, /* Size of changeset blob in bytes */
9935 void *pChangeset /* Pointer to blob containing changeset */
9937 SQLITE_API int sqlite3changeset_start_v2(
9938 sqlite3_changeset_iter **pp, /* OUT: New changeset iterator handle */
9939 int nChangeset, /* Size of changeset blob in bytes */
9940 void *pChangeset, /* Pointer to blob containing changeset */
9941 int flags /* SESSION_CHANGESETSTART_* flags */
9945 ** CAPI3REF: Flags for sqlite3changeset_start_v2
9947 ** The following flags may passed via the 4th parameter to
9948 ** [sqlite3changeset_start_v2] and [sqlite3changeset_start_v2_strm]:
9950 ** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
9951 ** Invert the changeset while iterating through it. This is equivalent to
9952 ** inverting a changeset using sqlite3changeset_invert() before applying it.
9953 ** It is an error to specify this flag with a patchset.
9955 #define SQLITE_CHANGESETSTART_INVERT 0x0002
9959 ** CAPI3REF: Advance A Changeset Iterator
9960 ** METHOD: sqlite3_changeset_iter
9962 ** This function may only be used with iterators created by function
9963 ** [sqlite3changeset_start()]. If it is called on an iterator passed to
9964 ** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
9965 ** is returned and the call has no effect.
9967 ** Immediately after an iterator is created by sqlite3changeset_start(), it
9968 ** does not point to any change in the changeset. Assuming the changeset
9969 ** is not empty, the first call to this function advances the iterator to
9970 ** point to the first change in the changeset. Each subsequent call advances
9971 ** the iterator to point to the next change in the changeset (if any). If
9972 ** no error occurs and the iterator points to a valid change after a call
9973 ** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned.
9974 ** Otherwise, if all changes in the changeset have already been visited,
9975 ** SQLITE_DONE is returned.
9977 ** If an error occurs, an SQLite error code is returned. Possible error
9978 ** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or
9981 SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *pIter);
9984 ** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
9985 ** METHOD: sqlite3_changeset_iter
9987 ** The pIter argument passed to this function may either be an iterator
9988 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
9989 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
9990 ** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
9991 ** is not the case, this function returns [SQLITE_MISUSE].
9993 ** If argument pzTab is not NULL, then *pzTab is set to point to a
9994 ** nul-terminated utf-8 encoded string containing the name of the table
9995 ** affected by the current change. The buffer remains valid until either
9996 ** sqlite3changeset_next() is called on the iterator or until the
9997 ** conflict-handler function returns. If pnCol is not NULL, then *pnCol is
9998 ** set to the number of columns in the table affected by the change. If
9999 ** pbIncorrect is not NULL, then *pbIndirect is set to true (1) if the change
10000 ** is an indirect change, or false (0) otherwise. See the documentation for
10001 ** [sqlite3session_indirect()] for a description of direct and indirect
10002 ** changes. Finally, if pOp is not NULL, then *pOp is set to one of
10003 ** [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE], depending on the
10004 ** type of change that the iterator currently points to.
10006 ** If no error occurs, SQLITE_OK is returned. If an error does occur, an
10007 ** SQLite error code is returned. The values of the output variables may not
10008 ** be trusted in this case.
10010 SQLITE_API int sqlite3changeset_op(
10011 sqlite3_changeset_iter *pIter, /* Iterator object */
10012 const char **pzTab, /* OUT: Pointer to table name */
10013 int *pnCol, /* OUT: Number of columns in table */
10014 int *pOp, /* OUT: SQLITE_INSERT, DELETE or UPDATE */
10015 int *pbIndirect /* OUT: True for an 'indirect' change */
10019 ** CAPI3REF: Obtain The Primary Key Definition Of A Table
10020 ** METHOD: sqlite3_changeset_iter
10022 ** For each modified table, a changeset includes the following:
10025 ** <li> The number of columns in the table, and
10026 ** <li> Which of those columns make up the tables PRIMARY KEY.
10029 ** This function is used to find which columns comprise the PRIMARY KEY of
10030 ** the table modified by the change that iterator pIter currently points to.
10031 ** If successful, *pabPK is set to point to an array of nCol entries, where
10032 ** nCol is the number of columns in the table. Elements of *pabPK are set to
10033 ** 0x01 if the corresponding column is part of the tables primary key, or
10034 ** 0x00 if it is not.
10036 ** If argument pnCol is not NULL, then *pnCol is set to the number of columns
10039 ** If this function is called when the iterator does not point to a valid
10040 ** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
10041 ** SQLITE_OK is returned and the output variables populated as described
10044 SQLITE_API int sqlite3changeset_pk(
10045 sqlite3_changeset_iter *pIter, /* Iterator object */
10046 unsigned char **pabPK, /* OUT: Array of boolean - true for PK cols */
10047 int *pnCol /* OUT: Number of entries in output array */
10051 ** CAPI3REF: Obtain old.* Values From A Changeset Iterator
10052 ** METHOD: sqlite3_changeset_iter
10054 ** The pIter argument passed to this function may either be an iterator
10055 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
10056 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
10057 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
10058 ** Furthermore, it may only be called if the type of change that the iterator
10059 ** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
10060 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
10062 ** Argument iVal must be greater than or equal to 0, and less than the number
10063 ** of columns in the table affected by the current change. Otherwise,
10064 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
10066 ** If successful, this function sets *ppValue to point to a protected
10067 ** sqlite3_value object containing the iVal'th value from the vector of
10068 ** original row values stored as part of the UPDATE or DELETE change and
10069 ** returns SQLITE_OK. The name of the function comes from the fact that this
10070 ** is similar to the "old.*" columns available to update or delete triggers.
10072 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
10073 ** is returned and *ppValue is set to NULL.
10075 SQLITE_API int sqlite3changeset_old(
10076 sqlite3_changeset_iter *pIter, /* Changeset iterator */
10077 int iVal, /* Column number */
10078 sqlite3_value **ppValue /* OUT: Old value (or NULL pointer) */
10082 ** CAPI3REF: Obtain new.* Values From A Changeset Iterator
10083 ** METHOD: sqlite3_changeset_iter
10085 ** The pIter argument passed to this function may either be an iterator
10086 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
10087 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
10088 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
10089 ** Furthermore, it may only be called if the type of change that the iterator
10090 ** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
10091 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
10093 ** Argument iVal must be greater than or equal to 0, and less than the number
10094 ** of columns in the table affected by the current change. Otherwise,
10095 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
10097 ** If successful, this function sets *ppValue to point to a protected
10098 ** sqlite3_value object containing the iVal'th value from the vector of
10099 ** new row values stored as part of the UPDATE or INSERT change and
10100 ** returns SQLITE_OK. If the change is an UPDATE and does not include
10101 ** a new value for the requested column, *ppValue is set to NULL and
10102 ** SQLITE_OK returned. The name of the function comes from the fact that
10103 ** this is similar to the "new.*" columns available to update or delete
10106 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
10107 ** is returned and *ppValue is set to NULL.
10109 SQLITE_API int sqlite3changeset_new(
10110 sqlite3_changeset_iter *pIter, /* Changeset iterator */
10111 int iVal, /* Column number */
10112 sqlite3_value **ppValue /* OUT: New value (or NULL pointer) */
10116 ** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
10117 ** METHOD: sqlite3_changeset_iter
10119 ** This function should only be used with iterator objects passed to a
10120 ** conflict-handler callback by [sqlite3changeset_apply()] with either
10121 ** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
10122 ** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
10125 ** Argument iVal must be greater than or equal to 0, and less than the number
10126 ** of columns in the table affected by the current change. Otherwise,
10127 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
10129 ** If successful, this function sets *ppValue to point to a protected
10130 ** sqlite3_value object containing the iVal'th value from the
10131 ** "conflicting row" associated with the current conflict-handler callback
10132 ** and returns SQLITE_OK.
10134 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
10135 ** is returned and *ppValue is set to NULL.
10137 SQLITE_API int sqlite3changeset_conflict(
10138 sqlite3_changeset_iter *pIter, /* Changeset iterator */
10139 int iVal, /* Column number */
10140 sqlite3_value **ppValue /* OUT: Value from conflicting row */
10144 ** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
10145 ** METHOD: sqlite3_changeset_iter
10147 ** This function may only be called with an iterator passed to an
10148 ** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
10149 ** it sets the output variable to the total number of known foreign key
10150 ** violations in the destination database and returns SQLITE_OK.
10152 ** In all other cases this function returns SQLITE_MISUSE.
10154 SQLITE_API int sqlite3changeset_fk_conflicts(
10155 sqlite3_changeset_iter *pIter, /* Changeset iterator */
10156 int *pnOut /* OUT: Number of FK violations */
10161 ** CAPI3REF: Finalize A Changeset Iterator
10162 ** METHOD: sqlite3_changeset_iter
10164 ** This function is used to finalize an iterator allocated with
10165 ** [sqlite3changeset_start()].
10167 ** This function should only be called on iterators created using the
10168 ** [sqlite3changeset_start()] function. If an application calls this
10169 ** function with an iterator passed to a conflict-handler by
10170 ** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
10171 ** call has no effect.
10173 ** If an error was encountered within a call to an sqlite3changeset_xxx()
10174 ** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an
10175 ** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
10176 ** to that error is returned by this function. Otherwise, SQLITE_OK is
10177 ** returned. This is to allow the following pattern (pseudo-code):
10180 ** sqlite3changeset_start();
10181 ** while( SQLITE_ROW==sqlite3changeset_next() ){
10182 ** // Do something with change.
10184 ** rc = sqlite3changeset_finalize();
10185 ** if( rc!=SQLITE_OK ){
10186 ** // An error has occurred
10190 SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);
10193 ** CAPI3REF: Invert A Changeset
10195 ** This function is used to "invert" a changeset object. Applying an inverted
10196 ** changeset to a database reverses the effects of applying the uninverted
10197 ** changeset. Specifically:
10200 ** <li> Each DELETE change is changed to an INSERT, and
10201 ** <li> Each INSERT change is changed to a DELETE, and
10202 ** <li> For each UPDATE change, the old.* and new.* values are exchanged.
10205 ** This function does not change the order in which changes appear within
10206 ** the changeset. It merely reverses the sense of each individual change.
10208 ** If successful, a pointer to a buffer containing the inverted changeset
10209 ** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
10210 ** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
10211 ** zeroed and an SQLite error code returned.
10213 ** It is the responsibility of the caller to eventually call sqlite3_free()
10214 ** on the *ppOut pointer to free the buffer allocation following a successful
10215 ** call to this function.
10217 ** WARNING/TODO: This function currently assumes that the input is a valid
10218 ** changeset. If it is not, the results are undefined.
10220 SQLITE_API int sqlite3changeset_invert(
10221 int nIn, const void *pIn, /* Input changeset */
10222 int *pnOut, void **ppOut /* OUT: Inverse of input */
10226 ** CAPI3REF: Concatenate Two Changeset Objects
10228 ** This function is used to concatenate two changesets, A and B, into a
10229 ** single changeset. The result is a changeset equivalent to applying
10230 ** changeset A followed by changeset B.
10232 ** This function combines the two input changesets using an
10233 ** sqlite3_changegroup object. Calling it produces similar results as the
10234 ** following code fragment:
10237 ** sqlite3_changegroup *pGrp;
10238 ** rc = sqlite3_changegroup_new(&pGrp);
10239 ** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
10240 ** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
10241 ** if( rc==SQLITE_OK ){
10242 ** rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
10249 ** Refer to the sqlite3_changegroup documentation below for details.
10251 SQLITE_API int sqlite3changeset_concat(
10252 int nA, /* Number of bytes in buffer pA */
10253 void *pA, /* Pointer to buffer containing changeset A */
10254 int nB, /* Number of bytes in buffer pB */
10255 void *pB, /* Pointer to buffer containing changeset B */
10256 int *pnOut, /* OUT: Number of bytes in output changeset */
10257 void **ppOut /* OUT: Buffer containing output changeset */
10262 ** CAPI3REF: Changegroup Handle
10264 ** A changegroup is an object used to combine two or more
10265 ** [changesets] or [patchsets]
10267 typedef struct sqlite3_changegroup sqlite3_changegroup;
10270 ** CAPI3REF: Create A New Changegroup Object
10271 ** CONSTRUCTOR: sqlite3_changegroup
10273 ** An sqlite3_changegroup object is used to combine two or more changesets
10274 ** (or patchsets) into a single changeset (or patchset). A single changegroup
10275 ** object may combine changesets or patchsets, but not both. The output is
10276 ** always in the same format as the input.
10278 ** If successful, this function returns SQLITE_OK and populates (*pp) with
10279 ** a pointer to a new sqlite3_changegroup object before returning. The caller
10280 ** should eventually free the returned object using a call to
10281 ** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
10282 ** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
10284 ** The usual usage pattern for an sqlite3_changegroup object is as follows:
10287 ** <li> It is created using a call to sqlite3changegroup_new().
10289 ** <li> Zero or more changesets (or patchsets) are added to the object
10290 ** by calling sqlite3changegroup_add().
10292 ** <li> The result of combining all input changesets together is obtained
10293 ** by the application via a call to sqlite3changegroup_output().
10295 ** <li> The object is deleted using a call to sqlite3changegroup_delete().
10298 ** Any number of calls to add() and output() may be made between the calls to
10299 ** new() and delete(), and in any order.
10301 ** As well as the regular sqlite3changegroup_add() and
10302 ** sqlite3changegroup_output() functions, also available are the streaming
10303 ** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
10305 SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp);
10308 ** CAPI3REF: Add A Changeset To A Changegroup
10309 ** METHOD: sqlite3_changegroup
10311 ** Add all changes within the changeset (or patchset) in buffer pData (size
10312 ** nData bytes) to the changegroup.
10314 ** If the buffer contains a patchset, then all prior calls to this function
10315 ** on the same changegroup object must also have specified patchsets. Or, if
10316 ** the buffer contains a changeset, so must have the earlier calls to this
10317 ** function. Otherwise, SQLITE_ERROR is returned and no changes are added
10318 ** to the changegroup.
10320 ** Rows within the changeset and changegroup are identified by the values in
10321 ** their PRIMARY KEY columns. A change in the changeset is considered to
10322 ** apply to the same row as a change already present in the changegroup if
10323 ** the two rows have the same primary key.
10325 ** Changes to rows that do not already appear in the changegroup are
10326 ** simply copied into it. Or, if both the new changeset and the changegroup
10327 ** contain changes that apply to a single row, the final contents of the
10328 ** changegroup depends on the type of each change, as follows:
10330 ** <table border=1 style="margin-left:8ex;margin-right:8ex">
10331 ** <tr><th style="white-space:pre">Existing Change </th>
10332 ** <th style="white-space:pre">New Change </th>
10333 ** <th>Output Change
10334 ** <tr><td>INSERT <td>INSERT <td>
10335 ** The new change is ignored. This case does not occur if the new
10336 ** changeset was recorded immediately after the changesets already
10337 ** added to the changegroup.
10338 ** <tr><td>INSERT <td>UPDATE <td>
10339 ** The INSERT change remains in the changegroup. The values in the
10340 ** INSERT change are modified as if the row was inserted by the
10341 ** existing change and then updated according to the new change.
10342 ** <tr><td>INSERT <td>DELETE <td>
10343 ** The existing INSERT is removed from the changegroup. The DELETE is
10345 ** <tr><td>UPDATE <td>INSERT <td>
10346 ** The new change is ignored. This case does not occur if the new
10347 ** changeset was recorded immediately after the changesets already
10348 ** added to the changegroup.
10349 ** <tr><td>UPDATE <td>UPDATE <td>
10350 ** The existing UPDATE remains within the changegroup. It is amended
10351 ** so that the accompanying values are as if the row was updated once
10352 ** by the existing change and then again by the new change.
10353 ** <tr><td>UPDATE <td>DELETE <td>
10354 ** The existing UPDATE is replaced by the new DELETE within the
10356 ** <tr><td>DELETE <td>INSERT <td>
10357 ** If one or more of the column values in the row inserted by the
10358 ** new change differ from those in the row deleted by the existing
10359 ** change, the existing DELETE is replaced by an UPDATE within the
10360 ** changegroup. Otherwise, if the inserted row is exactly the same
10361 ** as the deleted row, the existing DELETE is simply discarded.
10362 ** <tr><td>DELETE <td>UPDATE <td>
10363 ** The new change is ignored. This case does not occur if the new
10364 ** changeset was recorded immediately after the changesets already
10365 ** added to the changegroup.
10366 ** <tr><td>DELETE <td>DELETE <td>
10367 ** The new change is ignored. This case does not occur if the new
10368 ** changeset was recorded immediately after the changesets already
10369 ** added to the changegroup.
10372 ** If the new changeset contains changes to a table that is already present
10373 ** in the changegroup, then the number of columns and the position of the
10374 ** primary key columns for the table must be consistent. If this is not the
10375 ** case, this function fails with SQLITE_SCHEMA. If the input changeset
10376 ** appears to be corrupt and the corruption is detected, SQLITE_CORRUPT is
10377 ** returned. Or, if an out-of-memory condition occurs during processing, this
10378 ** function returns SQLITE_NOMEM. In all cases, if an error occurs the
10379 ** final contents of the changegroup is undefined.
10381 ** If no error occurs, SQLITE_OK is returned.
10383 SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData);
10386 ** CAPI3REF: Obtain A Composite Changeset From A Changegroup
10387 ** METHOD: sqlite3_changegroup
10389 ** Obtain a buffer containing a changeset (or patchset) representing the
10390 ** current contents of the changegroup. If the inputs to the changegroup
10391 ** were themselves changesets, the output is a changeset. Or, if the
10392 ** inputs were patchsets, the output is also a patchset.
10394 ** As with the output of the sqlite3session_changeset() and
10395 ** sqlite3session_patchset() functions, all changes related to a single
10396 ** table are grouped together in the output of this function. Tables appear
10397 ** in the same order as for the very first changeset added to the changegroup.
10398 ** If the second or subsequent changesets added to the changegroup contain
10399 ** changes for tables that do not appear in the first changeset, they are
10400 ** appended onto the end of the output changeset, again in the order in
10401 ** which they are first encountered.
10403 ** If an error occurs, an SQLite error code is returned and the output
10404 ** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
10405 ** is returned and the output variables are set to the size of and a
10406 ** pointer to the output buffer, respectively. In this case it is the
10407 ** responsibility of the caller to eventually free the buffer using a
10408 ** call to sqlite3_free().
10410 SQLITE_API int sqlite3changegroup_output(
10411 sqlite3_changegroup*,
10412 int *pnData, /* OUT: Size of output buffer in bytes */
10413 void **ppData /* OUT: Pointer to output buffer */
10417 ** CAPI3REF: Delete A Changegroup Object
10418 ** DESTRUCTOR: sqlite3_changegroup
10420 SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup*);
10423 ** CAPI3REF: Apply A Changeset To A Database
10425 ** Apply a changeset or patchset to a database. These functions attempt to
10426 ** update the "main" database attached to handle db with the changes found in
10427 ** the changeset passed via the second and third arguments.
10429 ** The fourth argument (xFilter) passed to these functions is the "filter
10430 ** callback". If it is not NULL, then for each table affected by at least one
10431 ** change in the changeset, the filter callback is invoked with
10432 ** the table name as the second argument, and a copy of the context pointer
10433 ** passed as the sixth argument as the first. If the "filter callback"
10434 ** returns zero, then no attempt is made to apply any changes to the table.
10435 ** Otherwise, if the return value is non-zero or the xFilter argument to
10436 ** is NULL, all changes related to the table are attempted.
10438 ** For each table that is not excluded by the filter callback, this function
10439 ** tests that the target database contains a compatible table. A table is
10440 ** considered compatible if all of the following are true:
10443 ** <li> The table has the same name as the name recorded in the
10445 ** <li> The table has at least as many columns as recorded in the
10447 ** <li> The table has primary key columns in the same position as
10448 ** recorded in the changeset.
10451 ** If there is no compatible table, it is not an error, but none of the
10452 ** changes associated with the table are applied. A warning message is issued
10453 ** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
10454 ** one such warning is issued for each table in the changeset.
10456 ** For each change for which there is a compatible table, an attempt is made
10457 ** to modify the table contents according to the UPDATE, INSERT or DELETE
10458 ** change. If a change cannot be applied cleanly, the conflict handler
10459 ** function passed as the fifth argument to sqlite3changeset_apply() may be
10460 ** invoked. A description of exactly when the conflict handler is invoked for
10461 ** each type of change is below.
10463 ** Unlike the xFilter argument, xConflict may not be passed NULL. The results
10464 ** of passing anything other than a valid function pointer as the xConflict
10465 ** argument are undefined.
10467 ** Each time the conflict handler function is invoked, it must return one
10468 ** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or
10469 ** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
10470 ** if the second argument passed to the conflict handler is either
10471 ** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
10472 ** returns an illegal value, any changes already made are rolled back and
10473 ** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different
10474 ** actions are taken by sqlite3changeset_apply() depending on the value
10475 ** returned by each invocation of the conflict-handler function. Refer to
10476 ** the documentation for the three
10477 ** [SQLITE_CHANGESET_OMIT|available return values] for details.
10480 ** <dt>DELETE Changes<dd>
10481 ** For each DELETE change, the function checks if the target database
10482 ** contains a row with the same primary key value (or values) as the
10483 ** original row values stored in the changeset. If it does, and the values
10484 ** stored in all non-primary key columns also match the values stored in
10485 ** the changeset the row is deleted from the target database.
10487 ** If a row with matching primary key values is found, but one or more of
10488 ** the non-primary key fields contains a value different from the original
10489 ** row value stored in the changeset, the conflict-handler function is
10490 ** invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the
10491 ** database table has more columns than are recorded in the changeset,
10492 ** only the values of those non-primary key fields are compared against
10493 ** the current database contents - any trailing database table columns
10496 ** If no row with matching primary key values is found in the database,
10497 ** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
10498 ** passed as the second argument.
10500 ** If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
10501 ** (which can only happen if a foreign key constraint is violated), the
10502 ** conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
10503 ** passed as the second argument. This includes the case where the DELETE
10504 ** operation is attempted because an earlier call to the conflict handler
10505 ** function returned [SQLITE_CHANGESET_REPLACE].
10507 ** <dt>INSERT Changes<dd>
10508 ** For each INSERT change, an attempt is made to insert the new row into
10509 ** the database. If the changeset row contains fewer fields than the
10510 ** database table, the trailing fields are populated with their default
10513 ** If the attempt to insert the row fails because the database already
10514 ** contains a row with the same primary key values, the conflict handler
10515 ** function is invoked with the second argument set to
10516 ** [SQLITE_CHANGESET_CONFLICT].
10518 ** If the attempt to insert the row fails because of some other constraint
10519 ** violation (e.g. NOT NULL or UNIQUE), the conflict handler function is
10520 ** invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
10521 ** This includes the case where the INSERT operation is re-attempted because
10522 ** an earlier call to the conflict handler function returned
10523 ** [SQLITE_CHANGESET_REPLACE].
10525 ** <dt>UPDATE Changes<dd>
10526 ** For each UPDATE change, the function checks if the target database
10527 ** contains a row with the same primary key value (or values) as the
10528 ** original row values stored in the changeset. If it does, and the values
10529 ** stored in all modified non-primary key columns also match the values
10530 ** stored in the changeset the row is updated within the target database.
10532 ** If a row with matching primary key values is found, but one or more of
10533 ** the modified non-primary key fields contains a value different from an
10534 ** original row value stored in the changeset, the conflict-handler function
10535 ** is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
10536 ** UPDATE changes only contain values for non-primary key fields that are
10537 ** to be modified, only those fields need to match the original values to
10538 ** avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
10540 ** If no row with matching primary key values is found in the database,
10541 ** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
10542 ** passed as the second argument.
10544 ** If the UPDATE operation is attempted, but SQLite returns
10545 ** SQLITE_CONSTRAINT, the conflict-handler function is invoked with
10546 ** [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
10547 ** This includes the case where the UPDATE operation is attempted after
10548 ** an earlier call to the conflict handler function returned
10549 ** [SQLITE_CHANGESET_REPLACE].
10552 ** It is safe to execute SQL statements, including those that write to the
10553 ** table that the callback related to, from within the xConflict callback.
10554 ** This can be used to further customize the applications conflict
10555 ** resolution strategy.
10557 ** All changes made by these functions are enclosed in a savepoint transaction.
10558 ** If any other error (aside from a constraint failure when attempting to
10559 ** write to the target database) occurs, then the savepoint transaction is
10560 ** rolled back, restoring the target database to its original state, and an
10561 ** SQLite error code returned.
10563 ** If the output parameters (ppRebase) and (pnRebase) are non-NULL and
10564 ** the input is a changeset (not a patchset), then sqlite3changeset_apply_v2()
10565 ** may set (*ppRebase) to point to a "rebase" that may be used with the
10566 ** sqlite3_rebaser APIs buffer before returning. In this case (*pnRebase)
10567 ** is set to the size of the buffer in bytes. It is the responsibility of the
10568 ** caller to eventually free any such buffer using sqlite3_free(). The buffer
10569 ** is only allocated and populated if one or more conflicts were encountered
10570 ** while applying the patchset. See comments surrounding the sqlite3_rebaser
10571 ** APIs for further details.
10573 ** The behavior of sqlite3changeset_apply_v2() and its streaming equivalent
10574 ** may be modified by passing a combination of
10575 ** [SQLITE_CHANGESETAPPLY_NOSAVEPOINT | supported flags] as the 9th parameter.
10577 ** Note that the sqlite3changeset_apply_v2() API is still <b>experimental</b>
10578 ** and therefore subject to change.
10580 SQLITE_API int sqlite3changeset_apply(
10581 sqlite3 *db, /* Apply change to "main" db of this handle */
10582 int nChangeset, /* Size of changeset in bytes */
10583 void *pChangeset, /* Changeset blob */
10585 void *pCtx, /* Copy of sixth arg to _apply() */
10586 const char *zTab /* Table name */
10589 void *pCtx, /* Copy of sixth arg to _apply() */
10590 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */
10591 sqlite3_changeset_iter *p /* Handle describing change and conflict */
10593 void *pCtx /* First argument passed to xConflict */
10595 SQLITE_API int sqlite3changeset_apply_v2(
10596 sqlite3 *db, /* Apply change to "main" db of this handle */
10597 int nChangeset, /* Size of changeset in bytes */
10598 void *pChangeset, /* Changeset blob */
10600 void *pCtx, /* Copy of sixth arg to _apply() */
10601 const char *zTab /* Table name */
10604 void *pCtx, /* Copy of sixth arg to _apply() */
10605 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */
10606 sqlite3_changeset_iter *p /* Handle describing change and conflict */
10608 void *pCtx, /* First argument passed to xConflict */
10609 void **ppRebase, int *pnRebase, /* OUT: Rebase data */
10610 int flags /* SESSION_CHANGESETAPPLY_* flags */
10614 ** CAPI3REF: Flags for sqlite3changeset_apply_v2
10616 ** The following flags may passed via the 9th parameter to
10617 ** [sqlite3changeset_apply_v2] and [sqlite3changeset_apply_v2_strm]:
10620 ** <dt>SQLITE_CHANGESETAPPLY_NOSAVEPOINT <dd>
10621 ** Usually, the sessions module encloses all operations performed by
10622 ** a single call to apply_v2() or apply_v2_strm() in a [SAVEPOINT]. The
10623 ** SAVEPOINT is committed if the changeset or patchset is successfully
10624 ** applied, or rolled back if an error occurs. Specifying this flag
10625 ** causes the sessions module to omit this savepoint. In this case, if the
10626 ** caller has an open transaction or savepoint when apply_v2() is called,
10627 ** it may revert the partially applied changeset by rolling it back.
10629 ** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
10630 ** Invert the changeset before applying it. This is equivalent to inverting
10631 ** a changeset using sqlite3changeset_invert() before applying it. It is
10632 ** an error to specify this flag with a patchset.
10634 #define SQLITE_CHANGESETAPPLY_NOSAVEPOINT 0x0001
10635 #define SQLITE_CHANGESETAPPLY_INVERT 0x0002
10638 ** CAPI3REF: Constants Passed To The Conflict Handler
10640 ** Values that may be passed as the second argument to a conflict-handler.
10643 ** <dt>SQLITE_CHANGESET_DATA<dd>
10644 ** The conflict handler is invoked with CHANGESET_DATA as the second argument
10645 ** when processing a DELETE or UPDATE change if a row with the required
10646 ** PRIMARY KEY fields is present in the database, but one or more other
10647 ** (non primary-key) fields modified by the update do not contain the
10648 ** expected "before" values.
10650 ** The conflicting row, in this case, is the database row with the matching
10653 ** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
10654 ** The conflict handler is invoked with CHANGESET_NOTFOUND as the second
10655 ** argument when processing a DELETE or UPDATE change if a row with the
10656 ** required PRIMARY KEY fields is not present in the database.
10658 ** There is no conflicting row in this case. The results of invoking the
10659 ** sqlite3changeset_conflict() API are undefined.
10661 ** <dt>SQLITE_CHANGESET_CONFLICT<dd>
10662 ** CHANGESET_CONFLICT is passed as the second argument to the conflict
10663 ** handler while processing an INSERT change if the operation would result
10664 ** in duplicate primary key values.
10666 ** The conflicting row in this case is the database row with the matching
10669 ** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
10670 ** If foreign key handling is enabled, and applying a changeset leaves the
10671 ** database in a state containing foreign key violations, the conflict
10672 ** handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
10673 ** exactly once before the changeset is committed. If the conflict handler
10674 ** returns CHANGESET_OMIT, the changes, including those that caused the
10675 ** foreign key constraint violation, are committed. Or, if it returns
10676 ** CHANGESET_ABORT, the changeset is rolled back.
10678 ** No current or conflicting row information is provided. The only function
10679 ** it is possible to call on the supplied sqlite3_changeset_iter handle
10680 ** is sqlite3changeset_fk_conflicts().
10682 ** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
10683 ** If any other constraint violation occurs while applying a change (i.e.
10684 ** a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is
10685 ** invoked with CHANGESET_CONSTRAINT as the second argument.
10687 ** There is no conflicting row in this case. The results of invoking the
10688 ** sqlite3changeset_conflict() API are undefined.
10692 #define SQLITE_CHANGESET_DATA 1
10693 #define SQLITE_CHANGESET_NOTFOUND 2
10694 #define SQLITE_CHANGESET_CONFLICT 3
10695 #define SQLITE_CHANGESET_CONSTRAINT 4
10696 #define SQLITE_CHANGESET_FOREIGN_KEY 5
10699 ** CAPI3REF: Constants Returned By The Conflict Handler
10701 ** A conflict handler callback must return one of the following three values.
10704 ** <dt>SQLITE_CHANGESET_OMIT<dd>
10705 ** If a conflict handler returns this value no special action is taken. The
10706 ** change that caused the conflict is not applied. The session module
10707 ** continues to the next change in the changeset.
10709 ** <dt>SQLITE_CHANGESET_REPLACE<dd>
10710 ** This value may only be returned if the second argument to the conflict
10711 ** handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
10712 ** is not the case, any changes applied so far are rolled back and the
10713 ** call to sqlite3changeset_apply() returns SQLITE_MISUSE.
10715 ** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
10716 ** handler, then the conflicting row is either updated or deleted, depending
10717 ** on the type of change.
10719 ** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
10720 ** handler, then the conflicting row is removed from the database and a
10721 ** second attempt to apply the change is made. If this second attempt fails,
10722 ** the original row is restored to the database before continuing.
10724 ** <dt>SQLITE_CHANGESET_ABORT<dd>
10725 ** If this value is returned, any changes applied so far are rolled back
10726 ** and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
10729 #define SQLITE_CHANGESET_OMIT 0
10730 #define SQLITE_CHANGESET_REPLACE 1
10731 #define SQLITE_CHANGESET_ABORT 2
10734 ** CAPI3REF: Rebasing changesets
10737 ** Suppose there is a site hosting a database in state S0. And that
10738 ** modifications are made that move that database to state S1 and a
10739 ** changeset recorded (the "local" changeset). Then, a changeset based
10740 ** on S0 is received from another site (the "remote" changeset) and
10741 ** applied to the database. The database is then in state
10742 ** (S1+"remote"), where the exact state depends on any conflict
10743 ** resolution decisions (OMIT or REPLACE) made while applying "remote".
10744 ** Rebasing a changeset is to update it to take those conflict
10745 ** resolution decisions into account, so that the same conflicts
10746 ** do not have to be resolved elsewhere in the network.
10748 ** For example, if both the local and remote changesets contain an
10749 ** INSERT of the same key on "CREATE TABLE t1(a PRIMARY KEY, b)":
10751 ** local: INSERT INTO t1 VALUES(1, 'v1');
10752 ** remote: INSERT INTO t1 VALUES(1, 'v2');
10754 ** and the conflict resolution is REPLACE, then the INSERT change is
10755 ** removed from the local changeset (it was overridden). Or, if the
10756 ** conflict resolution was "OMIT", then the local changeset is modified
10757 ** to instead contain:
10759 ** UPDATE t1 SET b = 'v2' WHERE a=1;
10761 ** Changes within the local changeset are rebased as follows:
10764 ** <dt>Local INSERT<dd>
10765 ** This may only conflict with a remote INSERT. If the conflict
10766 ** resolution was OMIT, then add an UPDATE change to the rebased
10767 ** changeset. Or, if the conflict resolution was REPLACE, add
10768 ** nothing to the rebased changeset.
10770 ** <dt>Local DELETE<dd>
10771 ** This may conflict with a remote UPDATE or DELETE. In both cases the
10772 ** only possible resolution is OMIT. If the remote operation was a
10773 ** DELETE, then add no change to the rebased changeset. If the remote
10774 ** operation was an UPDATE, then the old.* fields of change are updated
10775 ** to reflect the new.* values in the UPDATE.
10777 ** <dt>Local UPDATE<dd>
10778 ** This may conflict with a remote UPDATE or DELETE. If it conflicts
10779 ** with a DELETE, and the conflict resolution was OMIT, then the update
10780 ** is changed into an INSERT. Any undefined values in the new.* record
10781 ** from the update change are filled in using the old.* values from
10782 ** the conflicting DELETE. Or, if the conflict resolution was REPLACE,
10783 ** the UPDATE change is simply omitted from the rebased changeset.
10785 ** If conflict is with a remote UPDATE and the resolution is OMIT, then
10786 ** the old.* values are rebased using the new.* values in the remote
10787 ** change. Or, if the resolution is REPLACE, then the change is copied
10788 ** into the rebased changeset with updates to columns also updated by
10789 ** the conflicting remote UPDATE removed. If this means no columns would
10790 ** be updated, the change is omitted.
10793 ** A local change may be rebased against multiple remote changes
10794 ** simultaneously. If a single key is modified by multiple remote
10795 ** changesets, they are combined as follows before the local changeset
10799 ** <li> If there has been one or more REPLACE resolutions on a
10800 ** key, it is rebased according to a REPLACE.
10802 ** <li> If there have been no REPLACE resolutions on a key, then
10803 ** the local changeset is rebased according to the most recent
10804 ** of the OMIT resolutions.
10807 ** Note that conflict resolutions from multiple remote changesets are
10808 ** combined on a per-field basis, not per-row. This means that in the
10809 ** case of multiple remote UPDATE operations, some fields of a single
10810 ** local change may be rebased for REPLACE while others are rebased for
10813 ** In order to rebase a local changeset, the remote changeset must first
10814 ** be applied to the local database using sqlite3changeset_apply_v2() and
10815 ** the buffer of rebase information captured. Then:
10818 ** <li> An sqlite3_rebaser object is created by calling
10819 ** sqlite3rebaser_create().
10820 ** <li> The new object is configured with the rebase buffer obtained from
10821 ** sqlite3changeset_apply_v2() by calling sqlite3rebaser_configure().
10822 ** If the local changeset is to be rebased against multiple remote
10823 ** changesets, then sqlite3rebaser_configure() should be called
10824 ** multiple times, in the same order that the multiple
10825 ** sqlite3changeset_apply_v2() calls were made.
10826 ** <li> Each local changeset is rebased by calling sqlite3rebaser_rebase().
10827 ** <li> The sqlite3_rebaser object is deleted by calling
10828 ** sqlite3rebaser_delete().
10831 typedef struct sqlite3_rebaser sqlite3_rebaser;
10834 ** CAPI3REF: Create a changeset rebaser object.
10837 ** Allocate a new changeset rebaser object. If successful, set (*ppNew) to
10838 ** point to the new object and return SQLITE_OK. Otherwise, if an error
10839 ** occurs, return an SQLite error code (e.g. SQLITE_NOMEM) and set (*ppNew)
10842 SQLITE_API int sqlite3rebaser_create(sqlite3_rebaser **ppNew);
10845 ** CAPI3REF: Configure a changeset rebaser object.
10848 ** Configure the changeset rebaser object to rebase changesets according
10849 ** to the conflict resolutions described by buffer pRebase (size nRebase
10850 ** bytes), which must have been obtained from a previous call to
10851 ** sqlite3changeset_apply_v2().
10853 SQLITE_API int sqlite3rebaser_configure(
10855 int nRebase, const void *pRebase
10859 ** CAPI3REF: Rebase a changeset
10862 ** Argument pIn must point to a buffer containing a changeset nIn bytes
10863 ** in size. This function allocates and populates a buffer with a copy
10864 ** of the changeset rebased rebased according to the configuration of the
10865 ** rebaser object passed as the first argument. If successful, (*ppOut)
10866 ** is set to point to the new buffer containing the rebased changset and
10867 ** (*pnOut) to its size in bytes and SQLITE_OK returned. It is the
10868 ** responsibility of the caller to eventually free the new buffer using
10869 ** sqlite3_free(). Otherwise, if an error occurs, (*ppOut) and (*pnOut)
10870 ** are set to zero and an SQLite error code returned.
10872 SQLITE_API int sqlite3rebaser_rebase(
10874 int nIn, const void *pIn,
10875 int *pnOut, void **ppOut
10879 ** CAPI3REF: Delete a changeset rebaser object.
10882 ** Delete the changeset rebaser object and all associated resources. There
10883 ** should be one call to this function for each successful invocation
10884 ** of sqlite3rebaser_create().
10886 SQLITE_API void sqlite3rebaser_delete(sqlite3_rebaser *p);
10889 ** CAPI3REF: Streaming Versions of API functions.
10891 ** The six streaming API xxx_strm() functions serve similar purposes to the
10892 ** corresponding non-streaming API functions:
10894 ** <table border=1 style="margin-left:8ex;margin-right:8ex">
10895 ** <tr><th>Streaming function<th>Non-streaming equivalent</th>
10896 ** <tr><td>sqlite3changeset_apply_strm<td>[sqlite3changeset_apply]
10897 ** <tr><td>sqlite3changeset_apply_strm_v2<td>[sqlite3changeset_apply_v2]
10898 ** <tr><td>sqlite3changeset_concat_strm<td>[sqlite3changeset_concat]
10899 ** <tr><td>sqlite3changeset_invert_strm<td>[sqlite3changeset_invert]
10900 ** <tr><td>sqlite3changeset_start_strm<td>[sqlite3changeset_start]
10901 ** <tr><td>sqlite3session_changeset_strm<td>[sqlite3session_changeset]
10902 ** <tr><td>sqlite3session_patchset_strm<td>[sqlite3session_patchset]
10905 ** Non-streaming functions that accept changesets (or patchsets) as input
10906 ** require that the entire changeset be stored in a single buffer in memory.
10907 ** Similarly, those that return a changeset or patchset do so by returning
10908 ** a pointer to a single large buffer allocated using sqlite3_malloc().
10909 ** Normally this is convenient. However, if an application running in a
10910 ** low-memory environment is required to handle very large changesets, the
10911 ** large contiguous memory allocations required can become onerous.
10913 ** In order to avoid this problem, instead of a single large buffer, input
10914 ** is passed to a streaming API functions by way of a callback function that
10915 ** the sessions module invokes to incrementally request input data as it is
10916 ** required. In all cases, a pair of API function parameters such as
10919 ** int nChangeset,
10920 ** void *pChangeset,
10926 ** int (*xInput)(void *pIn, void *pData, int *pnData),
10927 ** void *pIn,
10930 ** Each time the xInput callback is invoked by the sessions module, the first
10931 ** argument passed is a copy of the supplied pIn context pointer. The second
10932 ** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no
10933 ** error occurs the xInput method should copy up to (*pnData) bytes of data
10934 ** into the buffer and set (*pnData) to the actual number of bytes copied
10935 ** before returning SQLITE_OK. If the input is completely exhausted, (*pnData)
10936 ** should be set to zero to indicate this. Or, if an error occurs, an SQLite
10937 ** error code should be returned. In all cases, if an xInput callback returns
10938 ** an error, all processing is abandoned and the streaming API function
10939 ** returns a copy of the error code to the caller.
10941 ** In the case of sqlite3changeset_start_strm(), the xInput callback may be
10942 ** invoked by the sessions module at any point during the lifetime of the
10943 ** iterator. If such an xInput callback returns an error, the iterator enters
10944 ** an error state, whereby all subsequent calls to iterator functions
10945 ** immediately fail with the same error code as returned by xInput.
10947 ** Similarly, streaming API functions that return changesets (or patchsets)
10948 ** return them in chunks by way of a callback function instead of via a
10949 ** pointer to a single large buffer. In this case, a pair of parameters such
10953 ** int *pnChangeset,
10954 ** void **ppChangeset,
10960 ** int (*xOutput)(void *pOut, const void *pData, int nData),
10961 ** void *pOut
10964 ** The xOutput callback is invoked zero or more times to return data to
10965 ** the application. The first parameter passed to each call is a copy of the
10966 ** pOut pointer supplied by the application. The second parameter, pData,
10967 ** points to a buffer nData bytes in size containing the chunk of output
10968 ** data being returned. If the xOutput callback successfully processes the
10969 ** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
10970 ** it should return some other SQLite error code. In this case processing
10971 ** is immediately abandoned and the streaming API function returns a copy
10972 ** of the xOutput error code to the application.
10974 ** The sessions module never invokes an xOutput callback with the third
10975 ** parameter set to a value less than or equal to zero. Other than this,
10976 ** no guarantees are made as to the size of the chunks of data returned.
10978 SQLITE_API int sqlite3changeset_apply_strm(
10979 sqlite3 *db, /* Apply change to "main" db of this handle */
10980 int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
10981 void *pIn, /* First arg for xInput */
10983 void *pCtx, /* Copy of sixth arg to _apply() */
10984 const char *zTab /* Table name */
10987 void *pCtx, /* Copy of sixth arg to _apply() */
10988 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */
10989 sqlite3_changeset_iter *p /* Handle describing change and conflict */
10991 void *pCtx /* First argument passed to xConflict */
10993 SQLITE_API int sqlite3changeset_apply_v2_strm(
10994 sqlite3 *db, /* Apply change to "main" db of this handle */
10995 int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
10996 void *pIn, /* First arg for xInput */
10998 void *pCtx, /* Copy of sixth arg to _apply() */
10999 const char *zTab /* Table name */
11002 void *pCtx, /* Copy of sixth arg to _apply() */
11003 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */
11004 sqlite3_changeset_iter *p /* Handle describing change and conflict */
11006 void *pCtx, /* First argument passed to xConflict */
11007 void **ppRebase, int *pnRebase,
11010 SQLITE_API int sqlite3changeset_concat_strm(
11011 int (*xInputA)(void *pIn, void *pData, int *pnData),
11013 int (*xInputB)(void *pIn, void *pData, int *pnData),
11015 int (*xOutput)(void *pOut, const void *pData, int nData),
11018 SQLITE_API int sqlite3changeset_invert_strm(
11019 int (*xInput)(void *pIn, void *pData, int *pnData),
11021 int (*xOutput)(void *pOut, const void *pData, int nData),
11024 SQLITE_API int sqlite3changeset_start_strm(
11025 sqlite3_changeset_iter **pp,
11026 int (*xInput)(void *pIn, void *pData, int *pnData),
11029 SQLITE_API int sqlite3changeset_start_v2_strm(
11030 sqlite3_changeset_iter **pp,
11031 int (*xInput)(void *pIn, void *pData, int *pnData),
11035 SQLITE_API int sqlite3session_changeset_strm(
11036 sqlite3_session *pSession,
11037 int (*xOutput)(void *pOut, const void *pData, int nData),
11040 SQLITE_API int sqlite3session_patchset_strm(
11041 sqlite3_session *pSession,
11042 int (*xOutput)(void *pOut, const void *pData, int nData),
11045 SQLITE_API int sqlite3changegroup_add_strm(sqlite3_changegroup*,
11046 int (*xInput)(void *pIn, void *pData, int *pnData),
11049 SQLITE_API int sqlite3changegroup_output_strm(sqlite3_changegroup*,
11050 int (*xOutput)(void *pOut, const void *pData, int nData),
11053 SQLITE_API int sqlite3rebaser_rebase_strm(
11054 sqlite3_rebaser *pRebaser,
11055 int (*xInput)(void *pIn, void *pData, int *pnData),
11057 int (*xOutput)(void *pOut, const void *pData, int nData),
11062 ** CAPI3REF: Configure global parameters
11064 ** The sqlite3session_config() interface is used to make global configuration
11065 ** changes to the sessions module in order to tune it to the specific needs
11066 ** of the application.
11068 ** The sqlite3session_config() interface is not threadsafe. If it is invoked
11069 ** while any other thread is inside any other sessions method then the
11070 ** results are undefined. Furthermore, if it is invoked after any sessions
11071 ** related objects have been created, the results are also undefined.
11073 ** The first argument to the sqlite3session_config() function must be one
11074 ** of the SQLITE_SESSION_CONFIG_XXX constants defined below. The
11075 ** interpretation of the (void*) value passed as the second parameter and
11076 ** the effect of calling this function depends on the value of the first
11080 ** <dt>SQLITE_SESSION_CONFIG_STRMSIZE<dd>
11081 ** By default, the sessions module streaming interfaces attempt to input
11082 ** and output data in approximately 1 KiB chunks. This operand may be used
11083 ** to set and query the value of this configuration setting. The pointer
11084 ** passed as the second argument must point to a value of type (int).
11085 ** If this value is greater than 0, it is used as the new streaming data
11086 ** chunk size for both input and output. Before returning, the (int) value
11087 ** pointed to by pArg is set to the final value of the streaming interface
11091 ** This function returns SQLITE_OK if successful, or an SQLite error code
11094 SQLITE_API int sqlite3session_config(int op, void *pArg);
11097 ** CAPI3REF: Values for sqlite3session_config().
11099 #define SQLITE_SESSION_CONFIG_STRMSIZE 1
11102 ** Make sure we can call this stuff from C++.
11108 #endif /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
11110 /******** End of sqlite3session.h *********/
11111 /******** Begin file fts5.h *********/
11115 ** The author disclaims copyright to this source code. In place of
11116 ** a legal notice, here is a blessing:
11118 ** May you do good and not evil.
11119 ** May you find forgiveness for yourself and forgive others.
11120 ** May you share freely, never taking more than you give.
11122 ******************************************************************************
11124 ** Interfaces to extend FTS5. Using the interfaces defined in this file,
11125 ** FTS5 may be extended with:
11127 ** * custom tokenizers, and
11128 ** * custom auxiliary functions.
11140 /*************************************************************************
11141 ** CUSTOM AUXILIARY FUNCTIONS
11143 ** Virtual table implementations may overload SQL functions by implementing
11144 ** the sqlite3_module.xFindFunction() method.
11147 typedef struct Fts5ExtensionApi Fts5ExtensionApi;
11148 typedef struct Fts5Context Fts5Context;
11149 typedef struct Fts5PhraseIter Fts5PhraseIter;
11151 typedef void (*fts5_extension_function)(
11152 const Fts5ExtensionApi *pApi, /* API offered by current FTS version */
11153 Fts5Context *pFts, /* First arg to pass to pApi functions */
11154 sqlite3_context *pCtx, /* Context for returning result/error */
11155 int nVal, /* Number of values in apVal[] array */
11156 sqlite3_value **apVal /* Array of trailing arguments */
11159 struct Fts5PhraseIter {
11160 const unsigned char *a;
11161 const unsigned char *b;
11165 ** EXTENSION API FUNCTIONS
11167 ** xUserData(pFts):
11168 ** Return a copy of the context pointer the extension function was
11169 ** registered with.
11171 ** xColumnTotalSize(pFts, iCol, pnToken):
11172 ** If parameter iCol is less than zero, set output variable *pnToken
11173 ** to the total number of tokens in the FTS5 table. Or, if iCol is
11174 ** non-negative but less than the number of columns in the table, return
11175 ** the total number of tokens in column iCol, considering all rows in
11178 ** If parameter iCol is greater than or equal to the number of columns
11179 ** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
11180 ** an OOM condition or IO error), an appropriate SQLite error code is
11183 ** xColumnCount(pFts):
11184 ** Return the number of columns in the table.
11186 ** xColumnSize(pFts, iCol, pnToken):
11187 ** If parameter iCol is less than zero, set output variable *pnToken
11188 ** to the total number of tokens in the current row. Or, if iCol is
11189 ** non-negative but less than the number of columns in the table, set
11190 ** *pnToken to the number of tokens in column iCol of the current row.
11192 ** If parameter iCol is greater than or equal to the number of columns
11193 ** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
11194 ** an OOM condition or IO error), an appropriate SQLite error code is
11197 ** This function may be quite inefficient if used with an FTS5 table
11198 ** created with the "columnsize=0" option.
11201 ** This function attempts to retrieve the text of column iCol of the
11202 ** current document. If successful, (*pz) is set to point to a buffer
11203 ** containing the text in utf-8 encoding, (*pn) is set to the size in bytes
11204 ** (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
11205 ** if an error occurs, an SQLite error code is returned and the final values
11206 ** of (*pz) and (*pn) are undefined.
11209 ** Returns the number of phrases in the current query expression.
11212 ** Returns the number of tokens in phrase iPhrase of the query. Phrases
11213 ** are numbered starting from zero.
11216 ** Set *pnInst to the total number of occurrences of all phrases within
11217 ** the query within the current row. Return SQLITE_OK if successful, or
11218 ** an error code (i.e. SQLITE_NOMEM) if an error occurs.
11220 ** This API can be quite slow if used with an FTS5 table created with the
11221 ** "detail=none" or "detail=column" option. If the FTS5 table is created
11222 ** with either "detail=none" or "detail=column" and "content=" option
11223 ** (i.e. if it is a contentless table), then this API always returns 0.
11226 ** Query for the details of phrase match iIdx within the current row.
11227 ** Phrase matches are numbered starting from zero, so the iIdx argument
11228 ** should be greater than or equal to zero and smaller than the value
11229 ** output by xInstCount().
11231 ** Usually, output parameter *piPhrase is set to the phrase number, *piCol
11232 ** to the column in which it occurs and *piOff the token offset of the
11233 ** first token of the phrase. The exception is if the table was created
11234 ** with the offsets=0 option specified. In this case *piOff is always
11237 ** Returns SQLITE_OK if successful, or an error code (i.e. SQLITE_NOMEM)
11238 ** if an error occurs.
11240 ** This API can be quite slow if used with an FTS5 table created with the
11241 ** "detail=none" or "detail=column" option.
11244 ** Returns the rowid of the current row.
11247 ** Tokenize text using the tokenizer belonging to the FTS5 table.
11249 ** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
11250 ** This API function is used to query the FTS table for phrase iPhrase
11251 ** of the current query. Specifically, a query equivalent to:
11253 ** ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
11255 ** with $p set to a phrase equivalent to the phrase iPhrase of the
11256 ** current query is executed. Any column filter that applies to
11257 ** phrase iPhrase of the current query is included in $p. For each
11258 ** row visited, the callback function passed as the fourth argument
11259 ** is invoked. The context and API objects passed to the callback
11260 ** function may be used to access the properties of each matched row.
11261 ** Invoking Api.xUserData() returns a copy of the pointer passed as
11262 ** the third argument to pUserData.
11264 ** If the callback function returns any value other than SQLITE_OK, the
11265 ** query is abandoned and the xQueryPhrase function returns immediately.
11266 ** If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
11267 ** Otherwise, the error code is propagated upwards.
11269 ** If the query runs to completion without incident, SQLITE_OK is returned.
11270 ** Or, if some error occurs before the query completes or is aborted by
11271 ** the callback, an SQLite error code is returned.
11274 ** xSetAuxdata(pFts5, pAux, xDelete)
11276 ** Save the pointer passed as the second argument as the extension functions
11277 ** "auxiliary data". The pointer may then be retrieved by the current or any
11278 ** future invocation of the same fts5 extension function made as part of
11279 ** of the same MATCH query using the xGetAuxdata() API.
11281 ** Each extension function is allocated a single auxiliary data slot for
11282 ** each FTS query (MATCH expression). If the extension function is invoked
11283 ** more than once for a single FTS query, then all invocations share a
11284 ** single auxiliary data context.
11286 ** If there is already an auxiliary data pointer when this function is
11287 ** invoked, then it is replaced by the new pointer. If an xDelete callback
11288 ** was specified along with the original pointer, it is invoked at this
11291 ** The xDelete callback, if one is specified, is also invoked on the
11292 ** auxiliary data pointer after the FTS5 query has finished.
11294 ** If an error (e.g. an OOM condition) occurs within this function, an
11295 ** the auxiliary data is set to NULL and an error code returned. If the
11296 ** xDelete parameter was not NULL, it is invoked on the auxiliary data
11297 ** pointer before returning.
11300 ** xGetAuxdata(pFts5, bClear)
11302 ** Returns the current auxiliary data pointer for the fts5 extension
11303 ** function. See the xSetAuxdata() method for details.
11305 ** If the bClear argument is non-zero, then the auxiliary data is cleared
11306 ** (set to NULL) before this function returns. In this case the xDelete,
11307 ** if any, is not invoked.
11310 ** xRowCount(pFts5, pnRow)
11312 ** This function is used to retrieve the total number of rows in the table.
11313 ** In other words, the same value that would be returned by:
11315 ** SELECT count(*) FROM ftstable;
11318 ** This function is used, along with type Fts5PhraseIter and the xPhraseNext
11319 ** method, to iterate through all instances of a single query phrase within
11320 ** the current row. This is the same information as is accessible via the
11321 ** xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
11322 ** to use, this API may be faster under some circumstances. To iterate
11323 ** through instances of phrase iPhrase, use the following code:
11325 ** Fts5PhraseIter iter;
11327 ** for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
11329 ** pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
11331 ** // An instance of phrase iPhrase at offset iOff of column iCol
11334 ** The Fts5PhraseIter structure is defined above. Applications should not
11335 ** modify this structure directly - it should only be used as shown above
11336 ** with the xPhraseFirst() and xPhraseNext() API methods (and by
11337 ** xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
11339 ** This API can be quite slow if used with an FTS5 table created with the
11340 ** "detail=none" or "detail=column" option. If the FTS5 table is created
11341 ** with either "detail=none" or "detail=column" and "content=" option
11342 ** (i.e. if it is a contentless table), then this API always iterates
11343 ** through an empty set (all calls to xPhraseFirst() set iCol to -1).
11346 ** See xPhraseFirst above.
11348 ** xPhraseFirstColumn()
11349 ** This function and xPhraseNextColumn() are similar to the xPhraseFirst()
11350 ** and xPhraseNext() APIs described above. The difference is that instead
11351 ** of iterating through all instances of a phrase in the current row, these
11352 ** APIs are used to iterate through the set of columns in the current row
11353 ** that contain one or more instances of a specified phrase. For example:
11355 ** Fts5PhraseIter iter;
11357 ** for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
11359 ** pApi->xPhraseNextColumn(pFts, &iter, &iCol)
11361 ** // Column iCol contains at least one instance of phrase iPhrase
11364 ** This API can be quite slow if used with an FTS5 table created with the
11365 ** "detail=none" option. If the FTS5 table is created with either
11366 ** "detail=none" "content=" option (i.e. if it is a contentless table),
11367 ** then this API always iterates through an empty set (all calls to
11368 ** xPhraseFirstColumn() set iCol to -1).
11370 ** The information accessed using this API and its companion
11371 ** xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
11372 ** (or xInst/xInstCount). The chief advantage of this API is that it is
11373 ** significantly more efficient than those alternatives when used with
11374 ** "detail=column" tables.
11376 ** xPhraseNextColumn()
11377 ** See xPhraseFirstColumn above.
11379 struct Fts5ExtensionApi {
11380 int iVersion; /* Currently always set to 3 */
11382 void *(*xUserData)(Fts5Context*);
11384 int (*xColumnCount)(Fts5Context*);
11385 int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
11386 int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
11388 int (*xTokenize)(Fts5Context*,
11389 const char *pText, int nText, /* Text to tokenize */
11390 void *pCtx, /* Context passed to xToken() */
11391 int (*xToken)(void*, int, const char*, int, int, int) /* Callback */
11394 int (*xPhraseCount)(Fts5Context*);
11395 int (*xPhraseSize)(Fts5Context*, int iPhrase);
11397 int (*xInstCount)(Fts5Context*, int *pnInst);
11398 int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
11400 sqlite3_int64 (*xRowid)(Fts5Context*);
11401 int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
11402 int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
11404 int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
11405 int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
11407 int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
11408 void *(*xGetAuxdata)(Fts5Context*, int bClear);
11410 int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
11411 void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
11413 int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
11414 void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
11418 ** CUSTOM AUXILIARY FUNCTIONS
11419 *************************************************************************/
11421 /*************************************************************************
11422 ** CUSTOM TOKENIZERS
11424 ** Applications may also register custom tokenizer types. A tokenizer
11425 ** is registered by providing fts5 with a populated instance of the
11426 ** following structure. All structure methods must be defined, setting
11427 ** any member of the fts5_tokenizer struct to NULL leads to undefined
11428 ** behaviour. The structure methods are expected to function as follows:
11431 ** This function is used to allocate and initialize a tokenizer instance.
11432 ** A tokenizer instance is required to actually tokenize text.
11434 ** The first argument passed to this function is a copy of the (void*)
11435 ** pointer provided by the application when the fts5_tokenizer object
11436 ** was registered with FTS5 (the third argument to xCreateTokenizer()).
11437 ** The second and third arguments are an array of nul-terminated strings
11438 ** containing the tokenizer arguments, if any, specified following the
11439 ** tokenizer name as part of the CREATE VIRTUAL TABLE statement used
11440 ** to create the FTS5 table.
11442 ** The final argument is an output variable. If successful, (*ppOut)
11443 ** should be set to point to the new tokenizer handle and SQLITE_OK
11444 ** returned. If an error occurs, some value other than SQLITE_OK should
11445 ** be returned. In this case, fts5 assumes that the final value of *ppOut
11449 ** This function is invoked to delete a tokenizer handle previously
11450 ** allocated using xCreate(). Fts5 guarantees that this function will
11451 ** be invoked exactly once for each successful call to xCreate().
11454 ** This function is expected to tokenize the nText byte string indicated
11455 ** by argument pText. pText may or may not be nul-terminated. The first
11456 ** argument passed to this function is a pointer to an Fts5Tokenizer object
11457 ** returned by an earlier call to xCreate().
11459 ** The second argument indicates the reason that FTS5 is requesting
11460 ** tokenization of the supplied text. This is always one of the following
11463 ** <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
11464 ** or removed from the FTS table. The tokenizer is being invoked to
11465 ** determine the set of tokens to add to (or delete from) the
11468 ** <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
11469 ** against the FTS index. The tokenizer is being called to tokenize
11470 ** a bareword or quoted string specified as part of the query.
11472 ** <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
11473 ** FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
11474 ** followed by a "*" character, indicating that the last token
11475 ** returned by the tokenizer will be treated as a token prefix.
11477 ** <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
11478 ** satisfy an fts5_api.xTokenize() request made by an auxiliary
11479 ** function. Or an fts5_api.xColumnSize() request made by the same
11480 ** on a columnsize=0 database.
11483 ** For each token in the input string, the supplied callback xToken() must
11484 ** be invoked. The first argument to it should be a copy of the pointer
11485 ** passed as the second argument to xTokenize(). The third and fourth
11486 ** arguments are a pointer to a buffer containing the token text, and the
11487 ** size of the token in bytes. The 4th and 5th arguments are the byte offsets
11488 ** of the first byte of and first byte immediately following the text from
11489 ** which the token is derived within the input.
11491 ** The second argument passed to the xToken() callback ("tflags") should
11492 ** normally be set to 0. The exception is if the tokenizer supports
11493 ** synonyms. In this case see the discussion below for details.
11495 ** FTS5 assumes the xToken() callback is invoked for each token in the
11496 ** order that they occur within the input text.
11498 ** If an xToken() callback returns any value other than SQLITE_OK, then
11499 ** the tokenization should be abandoned and the xTokenize() method should
11500 ** immediately return a copy of the xToken() return value. Or, if the
11501 ** input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
11502 ** if an error occurs with the xTokenize() implementation itself, it
11503 ** may abandon the tokenization and return any error code other than
11504 ** SQLITE_OK or SQLITE_DONE.
11508 ** Custom tokenizers may also support synonyms. Consider a case in which a
11509 ** user wishes to query for a phrase such as "first place". Using the
11510 ** built-in tokenizers, the FTS5 query 'first + place' will match instances
11511 ** of "first place" within the document set, but not alternative forms
11512 ** such as "1st place". In some applications, it would be better to match
11513 ** all instances of "first place" or "1st place" regardless of which form
11514 ** the user specified in the MATCH query text.
11516 ** There are several ways to approach this in FTS5:
11518 ** <ol><li> By mapping all synonyms to a single token. In this case, the
11519 ** In the above example, this means that the tokenizer returns the
11520 ** same token for inputs "first" and "1st". Say that token is in
11521 ** fact "first", so that when the user inserts the document "I won
11522 ** 1st place" entries are added to the index for tokens "i", "won",
11523 ** "first" and "place". If the user then queries for '1st + place',
11524 ** the tokenizer substitutes "first" for "1st" and the query works
11527 ** <li> By adding multiple synonyms for a single term to the FTS index.
11528 ** In this case, when tokenizing query text, the tokenizer may
11529 ** provide multiple synonyms for a single term within the document.
11530 ** FTS5 then queries the index for each synonym individually. For
11531 ** example, faced with the query:
11534 ** ... MATCH 'first place'</codeblock>
11536 ** the tokenizer offers both "1st" and "first" as synonyms for the
11537 ** first token in the MATCH query and FTS5 effectively runs a query
11541 ** ... MATCH '(first OR 1st) place'</codeblock>
11543 ** except that, for the purposes of auxiliary functions, the query
11544 ** still appears to contain just two phrases - "(first OR 1st)"
11545 ** being treated as a single phrase.
11547 ** <li> By adding multiple synonyms for a single term to the FTS index.
11548 ** Using this method, when tokenizing document text, the tokenizer
11549 ** provides multiple synonyms for each token. So that when a
11550 ** document such as "I won first place" is tokenized, entries are
11551 ** added to the FTS index for "i", "won", "first", "1st" and
11554 ** This way, even if the tokenizer does not provide synonyms
11555 ** when tokenizing query text (it should not - to do would be
11556 ** inefficient), it doesn't matter if the user queries for
11557 ** 'first + place' or '1st + place', as there are entries in the
11558 ** FTS index corresponding to both forms of the first token.
11561 ** Whether it is parsing document or query text, any call to xToken that
11562 ** specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
11563 ** is considered to supply a synonym for the previous token. For example,
11564 ** when parsing the document "I won first place", a tokenizer that supports
11565 ** synonyms would call xToken() 5 times, as follows:
11568 ** xToken(pCtx, 0, "i", 1, 0, 1);
11569 ** xToken(pCtx, 0, "won", 3, 2, 5);
11570 ** xToken(pCtx, 0, "first", 5, 6, 11);
11571 ** xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3, 6, 11);
11572 ** xToken(pCtx, 0, "place", 5, 12, 17);
11575 ** It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
11576 ** xToken() is called. Multiple synonyms may be specified for a single token
11577 ** by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
11578 ** There is no limit to the number of synonyms that may be provided for a
11581 ** In many cases, method (1) above is the best approach. It does not add
11582 ** extra data to the FTS index or require FTS5 to query for multiple terms,
11583 ** so it is efficient in terms of disk space and query speed. However, it
11584 ** does not support prefix queries very well. If, as suggested above, the
11585 ** token "first" is substituted for "1st" by the tokenizer, then the query:
11588 ** ... MATCH '1s*'</codeblock>
11590 ** will not match documents that contain the token "1st" (as the tokenizer
11591 ** will probably not map "1s" to any prefix of "first").
11593 ** For full prefix support, method (3) may be preferred. In this case,
11594 ** because the index contains entries for both "first" and "1st", prefix
11595 ** queries such as 'fi*' or '1s*' will match correctly. However, because
11596 ** extra entries are added to the FTS index, this method uses more space
11597 ** within the database.
11599 ** Method (2) offers a midpoint between (1) and (3). Using this method,
11600 ** a query such as '1s*' will match documents that contain the literal
11601 ** token "1st", but not "first" (assuming the tokenizer is not able to
11602 ** provide synonyms for prefixes). However, a non-prefix query like '1st'
11603 ** will match against "1st" and "first". This method does not require
11604 ** extra disk space, as no extra entries are added to the FTS index.
11605 ** On the other hand, it may require more CPU cycles to run MATCH queries,
11606 ** as separate queries of the FTS index are required for each synonym.
11608 ** When using methods (2) or (3), it is important that the tokenizer only
11609 ** provide synonyms when tokenizing document text (method (2)) or query
11610 ** text (method (3)), not both. Doing so will not cause any errors, but is
11613 typedef struct Fts5Tokenizer Fts5Tokenizer;
11614 typedef struct fts5_tokenizer fts5_tokenizer;
11615 struct fts5_tokenizer {
11616 int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
11617 void (*xDelete)(Fts5Tokenizer*);
11618 int (*xTokenize)(Fts5Tokenizer*,
11620 int flags, /* Mask of FTS5_TOKENIZE_* flags */
11621 const char *pText, int nText,
11623 void *pCtx, /* Copy of 2nd argument to xTokenize() */
11624 int tflags, /* Mask of FTS5_TOKEN_* flags */
11625 const char *pToken, /* Pointer to buffer containing token */
11626 int nToken, /* Size of token in bytes */
11627 int iStart, /* Byte offset of token within input text */
11628 int iEnd /* Byte offset of end of token within input text */
11633 /* Flags that may be passed as the third argument to xTokenize() */
11634 #define FTS5_TOKENIZE_QUERY 0x0001
11635 #define FTS5_TOKENIZE_PREFIX 0x0002
11636 #define FTS5_TOKENIZE_DOCUMENT 0x0004
11637 #define FTS5_TOKENIZE_AUX 0x0008
11639 /* Flags that may be passed by the tokenizer implementation back to FTS5
11640 ** as the third argument to the supplied xToken callback. */
11641 #define FTS5_TOKEN_COLOCATED 0x0001 /* Same position as prev. token */
11644 ** END OF CUSTOM TOKENIZERS
11645 *************************************************************************/
11647 /*************************************************************************
11648 ** FTS5 EXTENSION REGISTRATION API
11650 typedef struct fts5_api fts5_api;
11652 int iVersion; /* Currently always set to 2 */
11654 /* Create a new tokenizer */
11655 int (*xCreateTokenizer)(
11659 fts5_tokenizer *pTokenizer,
11660 void (*xDestroy)(void*)
11663 /* Find an existing tokenizer */
11664 int (*xFindTokenizer)(
11668 fts5_tokenizer *pTokenizer
11671 /* Create a new auxiliary function */
11672 int (*xCreateFunction)(
11676 fts5_extension_function xFunction,
11677 void (*xDestroy)(void*)
11682 ** END OF REGISTRATION API
11683 *************************************************************************/
11686 } /* end of the 'extern "C"' block */
11689 #endif /* _FTS5_H */
11691 /******** End of fts5.h *********/