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 suppose 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 ** Add the ability to override 'extern'
49 # define SQLITE_EXTERN extern
58 ** These no-op macros are used in front of interfaces to mark those
59 ** interfaces as either deprecated or experimental. New applications
60 ** should not use deprecated interfaces - they are support for backwards
61 ** compatibility only. Application writers should be aware that
62 ** experimental interfaces are subject to change in point releases.
64 ** These macros used to resolve to various kinds of compiler magic that
65 ** would generate warning messages when they were used. But that
66 ** compiler magic ended up generating such a flurry of bug reports
67 ** that we have taken it all out and gone back to using simple
70 #define SQLITE_DEPRECATED
71 #define SQLITE_EXPERIMENTAL
74 ** Ensure these symbols were not defined by some previous header file.
77 # undef SQLITE_VERSION
79 #ifdef SQLITE_VERSION_NUMBER
80 # undef SQLITE_VERSION_NUMBER
84 ** CAPI3REF: Compile-Time Library Version Numbers
86 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
87 ** evaluates to a string literal that is the SQLite version in the
88 ** format "X.Y.Z" where X is the major version number (always 3 for
89 ** SQLite3) and Y is the minor version number and Z is the release number.)^
90 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
91 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
92 ** numbers used in [SQLITE_VERSION].)^
93 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
94 ** be larger than the release from which it is derived. Either Y will
95 ** be held constant and Z will be incremented or else Y will be incremented
96 ** and Z will be reset to zero.
98 ** Since version 3.6.18, SQLite source code has been stored in the
99 ** <a href="http://www.fossil-scm.org/">Fossil configuration management
100 ** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to
101 ** a string which identifies a particular check-in of SQLite
102 ** within its configuration management system. ^The SQLITE_SOURCE_ID
103 ** string contains the date and time of the check-in (UTC) and an SHA1
104 ** hash of the entire source tree.
106 ** See also: [sqlite3_libversion()],
107 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
108 ** [sqlite_version()] and [sqlite_source_id()].
110 #define SQLITE_VERSION "3.8.3.1"
111 #define SQLITE_VERSION_NUMBER 3008003
112 #define SQLITE_SOURCE_ID "2014-02-11 14:52:19 ea3317a4803d71d88183b29f1d3086f46d68a00e"
115 ** CAPI3REF: Run-Time Library Version Numbers
116 ** KEYWORDS: sqlite3_version, sqlite3_sourceid
118 ** These interfaces provide the same information as the [SQLITE_VERSION],
119 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
120 ** but are associated with the library instead of the header file. ^(Cautious
121 ** programmers might include assert() statements in their application to
122 ** verify that values returned by these interfaces match the macros in
123 ** the header, and thus insure that the application is
124 ** compiled with matching library and header files.
127 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
128 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
129 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
130 ** </pre></blockquote>)^
132 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
133 ** macro. ^The sqlite3_libversion() function returns a pointer to the
134 ** to the sqlite3_version[] string constant. The sqlite3_libversion()
135 ** function is provided for use in DLLs since DLL users usually do not have
136 ** direct access to string constants within the DLL. ^The
137 ** sqlite3_libversion_number() function returns an integer equal to
138 ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns
139 ** a pointer to a string constant whose value is the same as the
140 ** [SQLITE_SOURCE_ID] C preprocessor macro.
142 ** See also: [sqlite_version()] and [sqlite_source_id()].
144 SQLITE_API SQLITE_EXTERN
const char sqlite3_version
[];
145 SQLITE_API
const char *sqlite3_libversion(void);
146 SQLITE_API
const char *sqlite3_sourceid(void);
147 SQLITE_API
int sqlite3_libversion_number(void);
150 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
152 ** ^The sqlite3_compileoption_used() function returns 0 or 1
153 ** indicating whether the specified option was defined at
154 ** compile time. ^The SQLITE_ prefix may be omitted from the
155 ** option name passed to sqlite3_compileoption_used().
157 ** ^The sqlite3_compileoption_get() function allows iterating
158 ** over the list of options that were defined at compile time by
159 ** returning the N-th compile time option string. ^If N is out of range,
160 ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
161 ** prefix is omitted from any strings returned by
162 ** sqlite3_compileoption_get().
164 ** ^Support for the diagnostic functions sqlite3_compileoption_used()
165 ** and sqlite3_compileoption_get() may be omitted by specifying the
166 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
168 ** See also: SQL functions [sqlite_compileoption_used()] and
169 ** [sqlite_compileoption_get()] and the [compile_options pragma].
171 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
172 SQLITE_API
int sqlite3_compileoption_used(const char *zOptName
);
173 SQLITE_API
const char *sqlite3_compileoption_get(int N
);
177 ** CAPI3REF: Test To See If The Library Is Threadsafe
179 ** ^The sqlite3_threadsafe() function returns zero if and only if
180 ** SQLite was compiled with mutexing code omitted due to the
181 ** [SQLITE_THREADSAFE] compile-time option being set to 0.
183 ** SQLite can be compiled with or without mutexes. When
184 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
185 ** are enabled and SQLite is threadsafe. When the
186 ** [SQLITE_THREADSAFE] macro is 0,
187 ** the mutexes are omitted. Without the mutexes, it is not safe
188 ** to use SQLite concurrently from more than one thread.
190 ** Enabling mutexes incurs a measurable performance penalty.
191 ** So if speed is of utmost importance, it makes sense to disable
192 ** the mutexes. But for maximum safety, mutexes should be enabled.
193 ** ^The default behavior is for mutexes to be enabled.
195 ** This interface can be used by an application to make sure that the
196 ** version of SQLite that it is linking against was compiled with
197 ** the desired setting of the [SQLITE_THREADSAFE] macro.
199 ** This interface only reports on the compile-time mutex setting
200 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
201 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
202 ** can be fully or partially disabled using a call to [sqlite3_config()]
203 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
204 ** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the
205 ** sqlite3_threadsafe() function shows only the compile-time setting of
206 ** thread safety, not any run-time changes to that setting made by
207 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
208 ** is unchanged by calls to sqlite3_config().)^
210 ** See the [threading mode] documentation for additional information.
212 SQLITE_API
int sqlite3_threadsafe(void);
215 ** CAPI3REF: Database Connection Handle
216 ** KEYWORDS: {database connection} {database connections}
218 ** Each open SQLite database is represented by a pointer to an instance of
219 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3
220 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
221 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
222 ** and [sqlite3_close_v2()] are its destructors. There are many other
223 ** interfaces (such as
224 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
225 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
228 typedef struct sqlite3 sqlite3
;
231 ** CAPI3REF: 64-Bit Integer Types
232 ** KEYWORDS: sqlite_int64 sqlite_uint64
234 ** Because there is no cross-platform way to specify 64-bit integer types
235 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
237 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
238 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
239 ** compatibility only.
241 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
242 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
243 ** sqlite3_uint64 and sqlite_uint64 types can store integer values
244 ** between 0 and +18446744073709551615 inclusive.
246 #ifdef SQLITE_INT64_TYPE
247 typedef SQLITE_INT64_TYPE sqlite_int64
;
248 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64
;
249 #elif defined(_MSC_VER) || defined(__BORLANDC__)
250 typedef __int64 sqlite_int64
;
251 typedef unsigned __int64 sqlite_uint64
;
253 typedef long long int sqlite_int64
;
254 typedef unsigned long long int sqlite_uint64
;
256 typedef sqlite_int64 sqlite3_int64
;
257 typedef sqlite_uint64 sqlite3_uint64
;
260 ** If compiling for a processor that lacks floating point support,
261 ** substitute integer for floating-point.
263 #ifdef SQLITE_OMIT_FLOATING_POINT
264 # define double sqlite3_int64
268 ** CAPI3REF: Closing A Database Connection
270 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
271 ** for the [sqlite3] object.
272 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return SQLITE_OK if
273 ** the [sqlite3] object is successfully destroyed and all associated
274 ** resources are deallocated.
276 ** ^If the database connection is associated with unfinalized prepared
277 ** statements or unfinished sqlite3_backup objects then sqlite3_close()
278 ** will leave the database connection open and return [SQLITE_BUSY].
279 ** ^If sqlite3_close_v2() is called with unfinalized prepared statements
280 ** and unfinished sqlite3_backups, then the database connection becomes
281 ** an unusable "zombie" which will automatically be deallocated when the
282 ** last prepared statement is finalized or the last sqlite3_backup is
283 ** finished. The sqlite3_close_v2() interface is intended for use with
284 ** host languages that are garbage collected, and where the order in which
285 ** destructors are called is arbitrary.
287 ** Applications should [sqlite3_finalize | finalize] all [prepared statements],
288 ** [sqlite3_blob_close | close] all [BLOB handles], and
289 ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
290 ** with the [sqlite3] object prior to attempting to close the object. ^If
291 ** sqlite3_close_v2() is called on a [database connection] that still has
292 ** outstanding [prepared statements], [BLOB handles], and/or
293 ** [sqlite3_backup] objects then it returns SQLITE_OK but the deallocation
294 ** of resources is deferred until all [prepared statements], [BLOB handles],
295 ** and [sqlite3_backup] objects are also destroyed.
297 ** ^If an [sqlite3] object is destroyed while a transaction is open,
298 ** the transaction is automatically rolled back.
300 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
301 ** must be either a NULL
302 ** pointer or an [sqlite3] object pointer obtained
303 ** from [sqlite3_open()], [sqlite3_open16()], or
304 ** [sqlite3_open_v2()], and not previously closed.
305 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
306 ** argument is a harmless no-op.
308 SQLITE_API
int sqlite3_close(sqlite3
*);
309 SQLITE_API
int sqlite3_close_v2(sqlite3
*);
312 ** The type for a callback function.
313 ** This is legacy and deprecated. It is included for historical
314 ** compatibility and is not documented.
316 typedef int (*sqlite3_callback
)(void*,int,char**, char**);
319 ** CAPI3REF: One-Step Query Execution Interface
321 ** The sqlite3_exec() interface is a convenience wrapper around
322 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
323 ** that allows an application to run multiple statements of SQL
324 ** without having to use a lot of C code.
326 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
327 ** semicolon-separate SQL statements passed into its 2nd argument,
328 ** in the context of the [database connection] passed in as its 1st
329 ** argument. ^If the callback function of the 3rd argument to
330 ** sqlite3_exec() is not NULL, then it is invoked for each result row
331 ** coming out of the evaluated SQL statements. ^The 4th argument to
332 ** sqlite3_exec() is relayed through to the 1st argument of each
333 ** callback invocation. ^If the callback pointer to sqlite3_exec()
334 ** is NULL, then no callback is ever invoked and result rows are
337 ** ^If an error occurs while evaluating the SQL statements passed into
338 ** sqlite3_exec(), then execution of the current statement stops and
339 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
340 ** is not NULL then any error message is written into memory obtained
341 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
342 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
343 ** on error message strings returned through the 5th parameter of
344 ** of sqlite3_exec() after the error message string is no longer needed.
345 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
346 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
347 ** NULL before returning.
349 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
350 ** routine returns SQLITE_ABORT without invoking the callback again and
351 ** without running any subsequent SQL statements.
353 ** ^The 2nd argument to the sqlite3_exec() callback function is the
354 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
355 ** callback is an array of pointers to strings obtained as if from
356 ** [sqlite3_column_text()], one for each column. ^If an element of a
357 ** result row is NULL then the corresponding string pointer for the
358 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
359 ** sqlite3_exec() callback is an array of pointers to strings where each
360 ** entry represents the name of corresponding result column as obtained
361 ** from [sqlite3_column_name()].
363 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
364 ** to an empty string, or a pointer that contains only whitespace and/or
365 ** SQL comments, then no SQL statements are evaluated and the database
371 ** <li> The application must insure that the 1st parameter to sqlite3_exec()
372 ** is a valid and open [database connection].
373 ** <li> The application must not close the [database connection] specified by
374 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
375 ** <li> The application must not modify the SQL statement text passed into
376 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
379 SQLITE_API
int sqlite3_exec(
380 sqlite3
*, /* An open database */
381 const char *sql
, /* SQL to be evaluated */
382 int (*callback
)(void*,int,char**,char**), /* Callback function */
383 void *, /* 1st argument to callback */
384 char **errmsg
/* Error msg written here */
388 ** CAPI3REF: Result Codes
389 ** KEYWORDS: SQLITE_OK {error code} {error codes}
390 ** KEYWORDS: {result code} {result codes}
392 ** Many SQLite functions return an integer result code from the set shown
393 ** here in order to indicate success or failure.
395 ** New error codes may be added in future versions of SQLite.
397 ** See also: [SQLITE_IOERR_READ | extended result codes],
398 ** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes].
400 #define SQLITE_OK 0 /* Successful result */
401 /* beginning-of-error-codes */
402 #define SQLITE_ERROR 1 /* SQL error or missing database */
403 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
404 #define SQLITE_PERM 3 /* Access permission denied */
405 #define SQLITE_ABORT 4 /* Callback routine requested an abort */
406 #define SQLITE_BUSY 5 /* The database file is locked */
407 #define SQLITE_LOCKED 6 /* A table in the database is locked */
408 #define SQLITE_NOMEM 7 /* A malloc() failed */
409 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */
410 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
411 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
412 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */
413 #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
414 #define SQLITE_FULL 13 /* Insertion failed because database is full */
415 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */
416 #define SQLITE_PROTOCOL 15 /* Database lock protocol error */
417 #define SQLITE_EMPTY 16 /* Database is empty */
418 #define SQLITE_SCHEMA 17 /* The database schema changed */
419 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
420 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
421 #define SQLITE_MISMATCH 20 /* Data type mismatch */
422 #define SQLITE_MISUSE 21 /* Library used incorrectly */
423 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
424 #define SQLITE_AUTH 23 /* Authorization denied */
425 #define SQLITE_FORMAT 24 /* Auxiliary database format error */
426 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
427 #define SQLITE_NOTADB 26 /* File opened that is not a database file */
428 #define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */
429 #define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */
430 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
431 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
432 /* end-of-error-codes */
435 ** CAPI3REF: Extended Result Codes
436 ** KEYWORDS: {extended error code} {extended error codes}
437 ** KEYWORDS: {extended result code} {extended result codes}
439 ** In its default configuration, SQLite API routines return one of 26 integer
440 ** [SQLITE_OK | result codes]. However, experience has shown that many of
441 ** these result codes are too coarse-grained. They do not provide as
442 ** much information about problems as programmers might like. In an effort to
443 ** address this, newer versions of SQLite (version 3.3.8 and later) include
444 ** support for additional result codes that provide more detailed information
445 ** about errors. The extended result codes are enabled or disabled
446 ** on a per database connection basis using the
447 ** [sqlite3_extended_result_codes()] API.
449 ** Some of the available extended result codes are listed here.
450 ** One may expect the number of extended result codes will increase
451 ** over time. Software that uses extended result codes should expect
452 ** to see new result codes in future releases of SQLite.
454 ** The SQLITE_OK result code will never be extended. It will always
457 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
458 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
459 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
460 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
461 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
462 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
463 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
464 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
465 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
466 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
467 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
468 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
469 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
470 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
471 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
472 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
473 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
474 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
475 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
476 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
477 #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
478 #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
479 #define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
480 #define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
481 #define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8))
482 #define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8))
483 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
484 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
485 #define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8))
486 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
487 #define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
488 #define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
489 #define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8))
490 #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
491 #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
492 #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
493 #define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8))
494 #define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8))
495 #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
496 #define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8))
497 #define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8))
498 #define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8))
499 #define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8))
500 #define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8))
501 #define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8))
502 #define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8))
503 #define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8))
504 #define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8))
505 #define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8))
506 #define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8))
507 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
508 #define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8))
511 ** CAPI3REF: Flags For File Open Operations
513 ** These bit values are intended for use in the
514 ** 3rd parameter to the [sqlite3_open_v2()] interface and
515 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
517 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
518 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
519 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
520 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
521 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
522 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
523 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
524 #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
525 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
526 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
527 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
528 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
529 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
530 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
531 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
532 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
533 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
534 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
535 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
536 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
538 /* Reserved: 0x00F00000 */
541 ** CAPI3REF: Device Characteristics
543 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
544 ** object returns an integer which is a vector of these
545 ** bit values expressing I/O characteristics of the mass storage
546 ** device that holds the file that the [sqlite3_io_methods]
549 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
550 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
551 ** mean that writes of blocks that are nnn bytes in size and
552 ** are aligned to an address which is an integer multiple of
553 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
554 ** that when data is appended to a file, the data is appended
555 ** first then the size of the file is extended, never the other
556 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
557 ** information is written to disk in the same order as calls
558 ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
559 ** after reboot following a crash or power loss, the only bytes in a
560 ** file that were written at the application level might have changed
561 ** and that adjacent bytes, even bytes within the same sector are
562 ** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
563 ** flag indicate that a file cannot be deleted when open.
565 #define SQLITE_IOCAP_ATOMIC 0x00000001
566 #define SQLITE_IOCAP_ATOMIC512 0x00000002
567 #define SQLITE_IOCAP_ATOMIC1K 0x00000004
568 #define SQLITE_IOCAP_ATOMIC2K 0x00000008
569 #define SQLITE_IOCAP_ATOMIC4K 0x00000010
570 #define SQLITE_IOCAP_ATOMIC8K 0x00000020
571 #define SQLITE_IOCAP_ATOMIC16K 0x00000040
572 #define SQLITE_IOCAP_ATOMIC32K 0x00000080
573 #define SQLITE_IOCAP_ATOMIC64K 0x00000100
574 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
575 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
576 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
577 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
580 ** CAPI3REF: File Locking Levels
582 ** SQLite uses one of these integer values as the second
583 ** argument to calls it makes to the xLock() and xUnlock() methods
584 ** of an [sqlite3_io_methods] object.
586 #define SQLITE_LOCK_NONE 0
587 #define SQLITE_LOCK_SHARED 1
588 #define SQLITE_LOCK_RESERVED 2
589 #define SQLITE_LOCK_PENDING 3
590 #define SQLITE_LOCK_EXCLUSIVE 4
593 ** CAPI3REF: Synchronization Type Flags
595 ** When SQLite invokes the xSync() method of an
596 ** [sqlite3_io_methods] object it uses a combination of
597 ** these integer values as the second argument.
599 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
600 ** sync operation only needs to flush data to mass storage. Inode
601 ** information need not be flushed. If the lower four bits of the flag
602 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
603 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
604 ** to use Mac OS X style fullsync instead of fsync().
606 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
607 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
608 ** settings. The [synchronous pragma] determines when calls to the
609 ** xSync VFS method occur and applies uniformly across all platforms.
610 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
611 ** energetic or rigorous or forceful the sync operations are and
612 ** only make a difference on Mac OSX for the default SQLite code.
613 ** (Third-party VFS implementations might also make the distinction
614 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
615 ** operating systems natively supported by SQLite, only Mac OSX
616 ** cares about the difference.)
618 #define SQLITE_SYNC_NORMAL 0x00002
619 #define SQLITE_SYNC_FULL 0x00003
620 #define SQLITE_SYNC_DATAONLY 0x00010
623 ** CAPI3REF: OS Interface Open File Handle
625 ** An [sqlite3_file] object represents an open file in the
626 ** [sqlite3_vfs | OS interface layer]. Individual OS interface
627 ** implementations will
628 ** want to subclass this object by appending additional fields
629 ** for their own use. The pMethods entry is a pointer to an
630 ** [sqlite3_io_methods] object that defines methods for performing
631 ** I/O operations on the open file.
633 typedef struct sqlite3_file sqlite3_file
;
634 struct sqlite3_file
{
635 const struct sqlite3_io_methods
*pMethods
; /* Methods for an open file */
639 ** CAPI3REF: OS Interface File Virtual Methods Object
641 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
642 ** [sqlite3_file] object (or, more commonly, a subclass of the
643 ** [sqlite3_file] object) with a pointer to an instance of this object.
644 ** This object defines the methods used to perform various operations
645 ** against the open file represented by the [sqlite3_file] object.
647 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
648 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
649 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
650 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
651 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
654 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
655 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
656 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
657 ** flag may be ORed in to indicate that only the data of the file
658 ** and not its inode needs to be synced.
660 ** The integer values to xLock() and xUnlock() are one of
662 ** <li> [SQLITE_LOCK_NONE],
663 ** <li> [SQLITE_LOCK_SHARED],
664 ** <li> [SQLITE_LOCK_RESERVED],
665 ** <li> [SQLITE_LOCK_PENDING], or
666 ** <li> [SQLITE_LOCK_EXCLUSIVE].
668 ** xLock() increases the lock. xUnlock() decreases the lock.
669 ** The xCheckReservedLock() method checks whether any database connection,
670 ** either in this process or in some other process, is holding a RESERVED,
671 ** PENDING, or EXCLUSIVE lock on the file. It returns true
672 ** if such a lock exists and false otherwise.
674 ** The xFileControl() method is a generic interface that allows custom
675 ** VFS implementations to directly control an open file using the
676 ** [sqlite3_file_control()] interface. The second "op" argument is an
677 ** integer opcode. The third argument is a generic pointer intended to
678 ** point to a structure that may contain arguments or space in which to
679 ** write return values. Potential uses for xFileControl() might be
680 ** functions to enable blocking locks with timeouts, to change the
681 ** locking strategy (for example to use dot-file locks), to inquire
682 ** about the status of a lock, or to break stale locks. The SQLite
683 ** core reserves all opcodes less than 100 for its own use.
684 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
685 ** Applications that define a custom xFileControl method should use opcodes
686 ** greater than 100 to avoid conflicts. VFS implementations should
687 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
690 ** The xSectorSize() method returns the sector size of the
691 ** device that underlies the file. The sector size is the
692 ** minimum write that can be performed without disturbing
693 ** other bytes in the file. The xDeviceCharacteristics()
694 ** method returns a bit vector describing behaviors of the
695 ** underlying device:
698 ** <li> [SQLITE_IOCAP_ATOMIC]
699 ** <li> [SQLITE_IOCAP_ATOMIC512]
700 ** <li> [SQLITE_IOCAP_ATOMIC1K]
701 ** <li> [SQLITE_IOCAP_ATOMIC2K]
702 ** <li> [SQLITE_IOCAP_ATOMIC4K]
703 ** <li> [SQLITE_IOCAP_ATOMIC8K]
704 ** <li> [SQLITE_IOCAP_ATOMIC16K]
705 ** <li> [SQLITE_IOCAP_ATOMIC32K]
706 ** <li> [SQLITE_IOCAP_ATOMIC64K]
707 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
708 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
711 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
712 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
713 ** mean that writes of blocks that are nnn bytes in size and
714 ** are aligned to an address which is an integer multiple of
715 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
716 ** that when data is appended to a file, the data is appended
717 ** first then the size of the file is extended, never the other
718 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
719 ** information is written to disk in the same order as calls
722 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
723 ** in the unread portions of the buffer with zeros. A VFS that
724 ** fails to zero-fill short reads might seem to work. However,
725 ** failure to zero-fill short reads will eventually lead to
726 ** database corruption.
728 typedef struct sqlite3_io_methods sqlite3_io_methods
;
729 struct sqlite3_io_methods
{
731 int (*xClose
)(sqlite3_file
*);
732 int (*xRead
)(sqlite3_file
*, void*, int iAmt
, sqlite3_int64 iOfst
);
733 int (*xWrite
)(sqlite3_file
*, const void*, int iAmt
, sqlite3_int64 iOfst
);
734 int (*xTruncate
)(sqlite3_file
*, sqlite3_int64 size
);
735 int (*xSync
)(sqlite3_file
*, int flags
);
736 int (*xFileSize
)(sqlite3_file
*, sqlite3_int64
*pSize
);
737 int (*xLock
)(sqlite3_file
*, int);
738 int (*xUnlock
)(sqlite3_file
*, int);
739 int (*xCheckReservedLock
)(sqlite3_file
*, int *pResOut
);
740 int (*xFileControl
)(sqlite3_file
*, int op
, void *pArg
);
741 int (*xSectorSize
)(sqlite3_file
*);
742 int (*xDeviceCharacteristics
)(sqlite3_file
*);
743 /* Methods above are valid for version 1 */
744 int (*xShmMap
)(sqlite3_file
*, int iPg
, int pgsz
, int, void volatile**);
745 int (*xShmLock
)(sqlite3_file
*, int offset
, int n
, int flags
);
746 void (*xShmBarrier
)(sqlite3_file
*);
747 int (*xShmUnmap
)(sqlite3_file
*, int deleteFlag
);
748 /* Methods above are valid for version 2 */
749 int (*xFetch
)(sqlite3_file
*, sqlite3_int64 iOfst
, int iAmt
, void **pp
);
750 int (*xUnfetch
)(sqlite3_file
*, sqlite3_int64 iOfst
, void *p
);
751 /* Methods above are valid for version 3 */
752 /* Additional methods may be added in future releases */
756 ** CAPI3REF: Standard File Control Opcodes
758 ** These integer constants are opcodes for the xFileControl method
759 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
762 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
763 ** opcode causes the xFileControl method to write the current state of
764 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
765 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
766 ** into an integer that the pArg argument points to. This capability
767 ** is used during testing and only needs to be supported when SQLITE_TEST
770 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
771 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
772 ** layer a hint of how large the database file will grow to be during the
773 ** current transaction. This hint is not guaranteed to be accurate but it
774 ** is often close. The underlying VFS might choose to preallocate database
775 ** file space based on this hint in order to help writes to the database
778 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
779 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
780 ** extends and truncates the database file in chunks of a size specified
781 ** by the user. The fourth argument to [sqlite3_file_control()] should
782 ** point to an integer (type int) containing the new chunk-size to use
783 ** for the nominated database. Allocating database file space in large
784 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
785 ** improve performance on some systems.
787 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
788 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
789 ** to the [sqlite3_file] object associated with a particular database
790 ** connection. See the [sqlite3_file_control()] documentation for
791 ** additional information.
793 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
796 ** <li>[[SQLITE_FCNTL_SYNC]]
797 ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
798 ** sent to the VFS immediately before the xSync method is invoked on a
799 ** database file descriptor. Or, if the xSync method is not invoked
800 ** because the user has configured SQLite with
801 ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
802 ** of the xSync method. In most cases, the pointer argument passed with
803 ** this file-control is NULL. However, if the database file is being synced
804 ** as part of a multi-database commit, the argument points to a nul-terminated
805 ** string containing the transactions master-journal file name. VFSes that
806 ** do not need this signal should silently ignore this opcode. Applications
807 ** should not call [sqlite3_file_control()] with this opcode as doing so may
808 ** disrupt the operation of the specialized VFSes that do require it.
810 ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
811 ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
812 ** and sent to the VFS after a transaction has been committed immediately
813 ** but before the database is unlocked. VFSes that do not need this signal
814 ** should silently ignore this opcode. Applications should not call
815 ** [sqlite3_file_control()] with this opcode as doing so may disrupt the
816 ** operation of the specialized VFSes that do require it.
818 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
819 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
820 ** retry counts and intervals for certain disk I/O operations for the
821 ** windows [VFS] in order to provide robustness in the presence of
822 ** anti-virus programs. By default, the windows VFS will retry file read,
823 ** file write, and file delete operations up to 10 times, with a delay
824 ** of 25 milliseconds before the first retry and with the delay increasing
825 ** by an additional 25 milliseconds with each subsequent retry. This
826 ** opcode allows these two values (10 retries and 25 milliseconds of delay)
827 ** to be adjusted. The values are changed for all database connections
828 ** within the same process. The argument is a pointer to an array of two
829 ** integers where the first integer i the new retry count and the second
830 ** integer is the delay. If either integer is negative, then the setting
831 ** is not changed but instead the prior value of that setting is written
832 ** into the array entry, allowing the current retry settings to be
833 ** interrogated. The zDbName parameter is ignored.
835 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
836 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
837 ** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
838 ** write ahead log and shared memory files used for transaction control
839 ** are automatically deleted when the latest connection to the database
840 ** closes. Setting persistent WAL mode causes those files to persist after
841 ** close. Persisting the files is useful when other processes that do not
842 ** have write permission on the directory containing the database file want
843 ** to read the database file, as the WAL and shared memory files must exist
844 ** in order for the database to be readable. The fourth parameter to
845 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
846 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
847 ** WAL mode. If the integer is -1, then it is overwritten with the current
848 ** WAL persistence setting.
850 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
851 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
852 ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
853 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
854 ** xDeviceCharacteristics methods. The fourth parameter to
855 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
856 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
857 ** mode. If the integer is -1, then it is overwritten with the current
858 ** zero-damage mode setting.
860 ** <li>[[SQLITE_FCNTL_OVERWRITE]]
861 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
862 ** a write transaction to indicate that, unless it is rolled back for some
863 ** reason, the entire database file will be overwritten by the current
864 ** transaction. This is used by VACUUM operations.
866 ** <li>[[SQLITE_FCNTL_VFSNAME]]
867 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
868 ** all [VFSes] in the VFS stack. The names are of all VFS shims and the
869 ** final bottom-level VFS are written into memory obtained from
870 ** [sqlite3_malloc()] and the result is stored in the char* variable
871 ** that the fourth parameter of [sqlite3_file_control()] points to.
872 ** The caller is responsible for freeing the memory when done. As with
873 ** all file-control actions, there is no guarantee that this will actually
874 ** do anything. Callers should initialize the char* variable to a NULL
875 ** pointer in case this file-control is not implemented. This file-control
876 ** is intended for diagnostic use only.
878 ** <li>[[SQLITE_FCNTL_PRAGMA]]
879 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
880 ** file control is sent to the open [sqlite3_file] object corresponding
881 ** to the database file to which the pragma statement refers. ^The argument
882 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
883 ** pointers to strings (char**) in which the second element of the array
884 ** is the name of the pragma and the third element is the argument to the
885 ** pragma or NULL if the pragma has no argument. ^The handler for an
886 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
887 ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
888 ** or the equivalent and that string will become the result of the pragma or
889 ** the error message if the pragma fails. ^If the
890 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
891 ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
892 ** file control returns [SQLITE_OK], then the parser assumes that the
893 ** VFS has handled the PRAGMA itself and the parser generates a no-op
894 ** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns
895 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
896 ** that the VFS encountered an error while handling the [PRAGMA] and the
897 ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
898 ** file control occurs at the beginning of pragma statement analysis and so
899 ** it is able to override built-in [PRAGMA] statements.
901 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
902 ** ^The [SQLITE_FCNTL_BUSYHANDLER]
903 ** file-control may be invoked by SQLite on the database file handle
904 ** shortly after it is opened in order to provide a custom VFS with access
905 ** to the connections busy-handler callback. The argument is of type (void **)
906 ** - an array of two (void *) values. The first (void *) actually points
907 ** to a function of type (int (*)(void *)). In order to invoke the connections
908 ** busy-handler, this function should be invoked with the second (void *) in
909 ** the array as the only argument. If it returns non-zero, then the operation
910 ** should be retried. If it returns zero, the custom VFS should abandon the
911 ** current operation.
913 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
914 ** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
915 ** to have SQLite generate a
916 ** temporary filename using the same algorithm that is followed to generate
917 ** temporary filenames for TEMP tables and other internal uses. The
918 ** argument should be a char** which will be filled with the filename
919 ** written into memory obtained from [sqlite3_malloc()]. The caller should
920 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
922 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
923 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
924 ** maximum number of bytes that will be used for memory-mapped I/O.
925 ** The argument is a pointer to a value of type sqlite3_int64 that
926 ** is an advisory maximum number of bytes in the file to memory map. The
927 ** pointer is overwritten with the old value. The limit is not changed if
928 ** the value originally pointed to is negative, and so the current limit
929 ** can be queried by passing in a pointer to a negative number. This
930 ** file-control is used internally to implement [PRAGMA mmap_size].
932 ** <li>[[SQLITE_FCNTL_TRACE]]
933 ** The [SQLITE_FCNTL_TRACE] file control provides advisory information
934 ** to the VFS about what the higher layers of the SQLite stack are doing.
935 ** This file control is used by some VFS activity tracing [shims].
936 ** The argument is a zero-terminated string. Higher layers in the
937 ** SQLite stack may generate instances of this file control if
938 ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
940 ** <li>[[SQLITE_FCNTL_HAS_MOVED]]
941 ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
942 ** pointer to an integer and it writes a boolean into that integer depending
943 ** on whether or not the file has been renamed, moved, or deleted since it
948 #define SQLITE_FCNTL_LOCKSTATE 1
949 #define SQLITE_GET_LOCKPROXYFILE 2
950 #define SQLITE_SET_LOCKPROXYFILE 3
951 #define SQLITE_LAST_ERRNO 4
952 #define SQLITE_FCNTL_SIZE_HINT 5
953 #define SQLITE_FCNTL_CHUNK_SIZE 6
954 #define SQLITE_FCNTL_FILE_POINTER 7
955 #define SQLITE_FCNTL_SYNC_OMITTED 8
956 #define SQLITE_FCNTL_WIN32_AV_RETRY 9
957 #define SQLITE_FCNTL_PERSIST_WAL 10
958 #define SQLITE_FCNTL_OVERWRITE 11
959 #define SQLITE_FCNTL_VFSNAME 12
960 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
961 #define SQLITE_FCNTL_PRAGMA 14
962 #define SQLITE_FCNTL_BUSYHANDLER 15
963 #define SQLITE_FCNTL_TEMPFILENAME 16
964 #define SQLITE_FCNTL_MMAP_SIZE 18
965 #define SQLITE_FCNTL_TRACE 19
966 #define SQLITE_FCNTL_HAS_MOVED 20
967 #define SQLITE_FCNTL_SYNC 21
968 #define SQLITE_FCNTL_COMMIT_PHASETWO 22
971 ** CAPI3REF: Mutex Handle
973 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
974 ** abstract type for a mutex object. The SQLite core never looks
975 ** at the internal representation of an [sqlite3_mutex]. It only
976 ** deals with pointers to the [sqlite3_mutex] object.
978 ** Mutexes are created using [sqlite3_mutex_alloc()].
980 typedef struct sqlite3_mutex sqlite3_mutex
;
983 ** CAPI3REF: OS Interface Object
985 ** An instance of the sqlite3_vfs object defines the interface between
986 ** the SQLite core and the underlying operating system. The "vfs"
987 ** in the name of the object stands for "virtual file system". See
988 ** the [VFS | VFS documentation] for further information.
990 ** The value of the iVersion field is initially 1 but may be larger in
991 ** future versions of SQLite. Additional fields may be appended to this
992 ** object when the iVersion value is increased. Note that the structure
993 ** of the sqlite3_vfs object changes in the transaction between
994 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
997 ** The szOsFile field is the size of the subclassed [sqlite3_file]
998 ** structure used by this VFS. mxPathname is the maximum length of
999 ** a pathname in this VFS.
1001 ** Registered sqlite3_vfs objects are kept on a linked list formed by
1002 ** the pNext pointer. The [sqlite3_vfs_register()]
1003 ** and [sqlite3_vfs_unregister()] interfaces manage this list
1004 ** in a thread-safe way. The [sqlite3_vfs_find()] interface
1005 ** searches the list. Neither the application code nor the VFS
1006 ** implementation should use the pNext pointer.
1008 ** The pNext field is the only field in the sqlite3_vfs
1009 ** structure that SQLite will ever modify. SQLite will only access
1010 ** or modify this field while holding a particular static mutex.
1011 ** The application should never modify anything within the sqlite3_vfs
1012 ** object once the object has been registered.
1014 ** The zName field holds the name of the VFS module. The name must
1015 ** be unique across all VFS modules.
1017 ** [[sqlite3_vfs.xOpen]]
1018 ** ^SQLite guarantees that the zFilename parameter to xOpen
1019 ** is either a NULL pointer or string obtained
1020 ** from xFullPathname() with an optional suffix added.
1021 ** ^If a suffix is added to the zFilename parameter, it will
1022 ** consist of a single "-" character followed by no more than
1023 ** 11 alphanumeric and/or "-" characters.
1024 ** ^SQLite further guarantees that
1025 ** the string will be valid and unchanged until xClose() is
1026 ** called. Because of the previous sentence,
1027 ** the [sqlite3_file] can safely store a pointer to the
1028 ** filename if it needs to remember the filename for some reason.
1029 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1030 ** must invent its own temporary name for the file. ^Whenever the
1031 ** xFilename parameter is NULL it will also be the case that the
1032 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1034 ** The flags argument to xOpen() includes all bits set in
1035 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
1036 ** or [sqlite3_open16()] is used, then flags includes at least
1037 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1038 ** If xOpen() opens a file read-only then it sets *pOutFlags to
1039 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
1041 ** ^(SQLite will also add one of the following flags to the xOpen()
1042 ** call, depending on the object being opened:
1045 ** <li> [SQLITE_OPEN_MAIN_DB]
1046 ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
1047 ** <li> [SQLITE_OPEN_TEMP_DB]
1048 ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
1049 ** <li> [SQLITE_OPEN_TRANSIENT_DB]
1050 ** <li> [SQLITE_OPEN_SUBJOURNAL]
1051 ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
1052 ** <li> [SQLITE_OPEN_WAL]
1055 ** The file I/O implementation can use the object type flags to
1056 ** change the way it deals with files. For example, an application
1057 ** that does not care about crash recovery or rollback might make
1058 ** the open of a journal file a no-op. Writes to this journal would
1059 ** also be no-ops, and any attempt to read the journal would return
1060 ** SQLITE_IOERR. Or the implementation might recognize that a database
1061 ** file will be doing page-aligned sector reads and writes in a random
1062 ** order and set up its I/O subsystem accordingly.
1064 ** SQLite might also add one of the following flags to the xOpen method:
1067 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
1068 ** <li> [SQLITE_OPEN_EXCLUSIVE]
1071 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1072 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1073 ** will be set for TEMP databases and their journals, transient
1074 ** databases, and subjournals.
1076 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1077 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1078 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1079 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1080 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1081 ** be created, and that it is an error if it already exists.
1082 ** It is <i>not</i> used to indicate the file should be opened
1083 ** for exclusive access.
1085 ** ^At least szOsFile bytes of memory are allocated by SQLite
1086 ** to hold the [sqlite3_file] structure passed as the third
1087 ** argument to xOpen. The xOpen method does not have to
1088 ** allocate the structure; it should just fill it in. Note that
1089 ** the xOpen method must set the sqlite3_file.pMethods to either
1090 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1091 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1092 ** element will be valid after xOpen returns regardless of the success
1093 ** or failure of the xOpen call.
1095 ** [[sqlite3_vfs.xAccess]]
1096 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1097 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1098 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1099 ** to test whether a file is at least readable. The file can be a
1102 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1103 ** output buffer xFullPathname. The exact size of the output buffer
1104 ** is also passed as a parameter to both methods. If the output buffer
1105 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1106 ** handled as a fatal error by SQLite, vfs implementations should endeavor
1107 ** to prevent this by setting mxPathname to a sufficiently large value.
1109 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1110 ** interfaces are not strictly a part of the filesystem, but they are
1111 ** included in the VFS structure for completeness.
1112 ** The xRandomness() function attempts to return nBytes bytes
1113 ** of good-quality randomness into zOut. The return value is
1114 ** the actual number of bytes of randomness obtained.
1115 ** The xSleep() method causes the calling thread to sleep for at
1116 ** least the number of microseconds given. ^The xCurrentTime()
1117 ** method returns a Julian Day Number for the current date and time as
1118 ** a floating point value.
1119 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1120 ** Day Number multiplied by 86400000 (the number of milliseconds in
1122 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1123 ** date and time if that method is available (if iVersion is 2 or
1124 ** greater and the function pointer is not NULL) and will fall back
1125 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1127 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1128 ** are not used by the SQLite core. These optional interfaces are provided
1129 ** by some VFSes to facilitate testing of the VFS code. By overriding
1130 ** system calls with functions under its control, a test program can
1131 ** simulate faults and error conditions that would otherwise be difficult
1132 ** or impossible to induce. The set of system calls that can be overridden
1133 ** varies from one VFS to another, and from one version of the same VFS to the
1134 ** next. Applications that use these interfaces must be prepared for any
1135 ** or all of these interfaces to be NULL or for their behavior to change
1136 ** from one release to the next. Applications must not attempt to access
1137 ** any of these methods if the iVersion of the VFS is less than 3.
1139 typedef struct sqlite3_vfs sqlite3_vfs
;
1140 typedef void (*sqlite3_syscall_ptr
)(void);
1141 struct sqlite3_vfs
{
1142 int iVersion
; /* Structure version number (currently 3) */
1143 int szOsFile
; /* Size of subclassed sqlite3_file */
1144 int mxPathname
; /* Maximum file pathname length */
1145 sqlite3_vfs
*pNext
; /* Next registered VFS */
1146 const char *zName
; /* Name of this virtual file system */
1147 void *pAppData
; /* Pointer to application-specific data */
1148 int (*xOpen
)(sqlite3_vfs
*, const char *zName
, sqlite3_file
*,
1149 int flags
, int *pOutFlags
);
1150 int (*xDelete
)(sqlite3_vfs
*, const char *zName
, int syncDir
);
1151 int (*xAccess
)(sqlite3_vfs
*, const char *zName
, int flags
, int *pResOut
);
1152 int (*xFullPathname
)(sqlite3_vfs
*, const char *zName
, int nOut
, char *zOut
);
1153 void *(*xDlOpen
)(sqlite3_vfs
*, const char *zFilename
);
1154 void (*xDlError
)(sqlite3_vfs
*, int nByte
, char *zErrMsg
);
1155 void (*(*xDlSym
)(sqlite3_vfs
*,void*, const char *zSymbol
))(void);
1156 void (*xDlClose
)(sqlite3_vfs
*, void*);
1157 int (*xRandomness
)(sqlite3_vfs
*, int nByte
, char *zOut
);
1158 int (*xSleep
)(sqlite3_vfs
*, int microseconds
);
1159 int (*xCurrentTime
)(sqlite3_vfs
*, double*);
1160 int (*xGetLastError
)(sqlite3_vfs
*, int, char *);
1162 ** The methods above are in version 1 of the sqlite_vfs object
1163 ** definition. Those that follow are added in version 2 or later
1165 int (*xCurrentTimeInt64
)(sqlite3_vfs
*, sqlite3_int64
*);
1167 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1168 ** Those below are for version 3 and greater.
1170 int (*xSetSystemCall
)(sqlite3_vfs
*, const char *zName
, sqlite3_syscall_ptr
);
1171 sqlite3_syscall_ptr (*xGetSystemCall
)(sqlite3_vfs
*, const char *zName
);
1172 const char *(*xNextSystemCall
)(sqlite3_vfs
*, const char *zName
);
1174 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1175 ** New fields may be appended in figure versions. The iVersion
1176 ** value will increment whenever this happens.
1181 ** CAPI3REF: Flags for the xAccess VFS method
1183 ** These integer constants can be used as the third parameter to
1184 ** the xAccess method of an [sqlite3_vfs] object. They determine
1185 ** what kind of permissions the xAccess method is looking for.
1186 ** With SQLITE_ACCESS_EXISTS, the xAccess method
1187 ** simply checks whether the file exists.
1188 ** With SQLITE_ACCESS_READWRITE, the xAccess method
1189 ** checks whether the named directory is both readable and writable
1190 ** (in other words, if files can be added, removed, and renamed within
1192 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1193 ** [temp_store_directory pragma], though this could change in a future
1194 ** release of SQLite.
1195 ** With SQLITE_ACCESS_READ, the xAccess method
1196 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1197 ** currently unused, though it might be used in a future release of
1200 #define SQLITE_ACCESS_EXISTS 0
1201 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1202 #define SQLITE_ACCESS_READ 2 /* Unused */
1205 ** CAPI3REF: Flags for the xShmLock VFS method
1207 ** These integer constants define the various locking operations
1208 ** allowed by the xShmLock method of [sqlite3_io_methods]. The
1209 ** following are the only legal combinations of flags to the
1213 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1214 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1215 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1216 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1219 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1220 ** was given no the corresponding lock.
1222 ** The xShmLock method can transition between unlocked and SHARED or
1223 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1226 #define SQLITE_SHM_UNLOCK 1
1227 #define SQLITE_SHM_LOCK 2
1228 #define SQLITE_SHM_SHARED 4
1229 #define SQLITE_SHM_EXCLUSIVE 8
1232 ** CAPI3REF: Maximum xShmLock index
1234 ** The xShmLock method on [sqlite3_io_methods] may use values
1235 ** between 0 and this upper bound as its "offset" argument.
1236 ** The SQLite core will never attempt to acquire or release a
1237 ** lock outside of this range
1239 #define SQLITE_SHM_NLOCK 8
1243 ** CAPI3REF: Initialize The SQLite Library
1245 ** ^The sqlite3_initialize() routine initializes the
1246 ** SQLite library. ^The sqlite3_shutdown() routine
1247 ** deallocates any resources that were allocated by sqlite3_initialize().
1248 ** These routines are designed to aid in process initialization and
1249 ** shutdown on embedded systems. Workstation applications using
1250 ** SQLite normally do not need to invoke either of these routines.
1252 ** A call to sqlite3_initialize() is an "effective" call if it is
1253 ** the first time sqlite3_initialize() is invoked during the lifetime of
1254 ** the process, or if it is the first time sqlite3_initialize() is invoked
1255 ** following a call to sqlite3_shutdown(). ^(Only an effective call
1256 ** of sqlite3_initialize() does any initialization. All other calls
1257 ** are harmless no-ops.)^
1259 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1260 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1261 ** an effective call to sqlite3_shutdown() does any deinitialization.
1262 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1264 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1265 ** is not. The sqlite3_shutdown() interface must only be called from a
1266 ** single thread. All open [database connections] must be closed and all
1267 ** other SQLite resources must be deallocated prior to invoking
1268 ** sqlite3_shutdown().
1270 ** Among other things, ^sqlite3_initialize() will invoke
1271 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1272 ** will invoke sqlite3_os_end().
1274 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1275 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1276 ** the library (perhaps it is unable to allocate a needed resource such
1277 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1279 ** ^The sqlite3_initialize() routine is called internally by many other
1280 ** SQLite interfaces so that an application usually does not need to
1281 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1282 ** calls sqlite3_initialize() so the SQLite library will be automatically
1283 ** initialized when [sqlite3_open()] is called if it has not be initialized
1284 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1285 ** compile-time option, then the automatic calls to sqlite3_initialize()
1286 ** are omitted and the application must call sqlite3_initialize() directly
1287 ** prior to using any other SQLite interface. For maximum portability,
1288 ** it is recommended that applications always invoke sqlite3_initialize()
1289 ** directly prior to using any other SQLite interface. Future releases
1290 ** of SQLite may require this. In other words, the behavior exhibited
1291 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1292 ** default behavior in some future release of SQLite.
1294 ** The sqlite3_os_init() routine does operating-system specific
1295 ** initialization of the SQLite library. The sqlite3_os_end()
1296 ** routine undoes the effect of sqlite3_os_init(). Typical tasks
1297 ** performed by these routines include allocation or deallocation
1298 ** of static resources, initialization of global variables,
1299 ** setting up a default [sqlite3_vfs] module, or setting up
1300 ** a default configuration using [sqlite3_config()].
1302 ** The application should never invoke either sqlite3_os_init()
1303 ** or sqlite3_os_end() directly. The application should only invoke
1304 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1305 ** interface is called automatically by sqlite3_initialize() and
1306 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1307 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1308 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1309 ** When [custom builds | built for other platforms]
1310 ** (using the [SQLITE_OS_OTHER=1] compile-time
1311 ** option) the application must supply a suitable implementation for
1312 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1313 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1314 ** must return [SQLITE_OK] on success and some other [error code] upon
1317 SQLITE_API
int sqlite3_initialize(void);
1318 SQLITE_API
int sqlite3_shutdown(void);
1319 SQLITE_API
int sqlite3_os_init(void);
1320 SQLITE_API
int sqlite3_os_end(void);
1323 ** CAPI3REF: Configuring The SQLite Library
1325 ** The sqlite3_config() interface is used to make global configuration
1326 ** changes to SQLite in order to tune SQLite to the specific needs of
1327 ** the application. The default configuration is recommended for most
1328 ** applications and so this routine is usually not necessary. It is
1329 ** provided to support rare applications with unusual needs.
1331 ** The sqlite3_config() interface is not threadsafe. The application
1332 ** must insure that no other SQLite interfaces are invoked by other
1333 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config()
1334 ** may only be invoked prior to library initialization using
1335 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1336 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1337 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1338 ** Note, however, that ^sqlite3_config() can be called as part of the
1339 ** implementation of an application-defined [sqlite3_os_init()].
1341 ** The first argument to sqlite3_config() is an integer
1342 ** [configuration option] that determines
1343 ** what property of SQLite is to be configured. Subsequent arguments
1344 ** vary depending on the [configuration option]
1345 ** in the first argument.
1347 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1348 ** ^If the option is unknown or SQLite is unable to set the option
1349 ** then this routine returns a non-zero [error code].
1351 SQLITE_API
int sqlite3_config(int, ...);
1354 ** CAPI3REF: Configure database connections
1356 ** The sqlite3_db_config() interface is used to make configuration
1357 ** changes to a [database connection]. The interface is similar to
1358 ** [sqlite3_config()] except that the changes apply to a single
1359 ** [database connection] (specified in the first argument).
1361 ** The second argument to sqlite3_db_config(D,V,...) is the
1362 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1363 ** that indicates what aspect of the [database connection] is being configured.
1364 ** Subsequent arguments vary depending on the configuration verb.
1366 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1367 ** the call is considered successful.
1369 SQLITE_API
int sqlite3_db_config(sqlite3
*, int op
, ...);
1372 ** CAPI3REF: Memory Allocation Routines
1374 ** An instance of this object defines the interface between SQLite
1375 ** and low-level memory allocation routines.
1377 ** This object is used in only one place in the SQLite interface.
1378 ** A pointer to an instance of this object is the argument to
1379 ** [sqlite3_config()] when the configuration option is
1380 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1381 ** By creating an instance of this object
1382 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1383 ** during configuration, an application can specify an alternative
1384 ** memory allocation subsystem for SQLite to use for all of its
1385 ** dynamic memory needs.
1387 ** Note that SQLite comes with several [built-in memory allocators]
1388 ** that are perfectly adequate for the overwhelming majority of applications
1389 ** and that this object is only useful to a tiny minority of applications
1390 ** with specialized memory allocation requirements. This object is
1391 ** also used during testing of SQLite in order to specify an alternative
1392 ** memory allocator that simulates memory out-of-memory conditions in
1393 ** order to verify that SQLite recovers gracefully from such
1396 ** The xMalloc, xRealloc, and xFree methods must work like the
1397 ** malloc(), realloc() and free() functions from the standard C library.
1398 ** ^SQLite guarantees that the second argument to
1399 ** xRealloc is always a value returned by a prior call to xRoundup.
1401 ** xSize should return the allocated size of a memory allocation
1402 ** previously obtained from xMalloc or xRealloc. The allocated size
1403 ** is always at least as big as the requested size but may be larger.
1405 ** The xRoundup method returns what would be the allocated size of
1406 ** a memory allocation given a particular requested size. Most memory
1407 ** allocators round up memory allocations at least to the next multiple
1408 ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1409 ** Every memory allocation request coming in through [sqlite3_malloc()]
1410 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1411 ** that causes the corresponding memory allocation to fail.
1413 ** The xInit method initializes the memory allocator. For example,
1414 ** it might allocate any require mutexes or initialize internal data
1415 ** structures. The xShutdown method is invoked (indirectly) by
1416 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1417 ** by xInit. The pAppData pointer is used as the only parameter to
1418 ** xInit and xShutdown.
1420 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1421 ** the xInit method, so the xInit method need not be threadsafe. The
1422 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1423 ** not need to be threadsafe either. For all other methods, SQLite
1424 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1425 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1426 ** it is by default) and so the methods are automatically serialized.
1427 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1428 ** methods must be threadsafe or else make their own arrangements for
1431 ** SQLite will never invoke xInit() more than once without an intervening
1432 ** call to xShutdown().
1434 typedef struct sqlite3_mem_methods sqlite3_mem_methods
;
1435 struct sqlite3_mem_methods
{
1436 void *(*xMalloc
)(int); /* Memory allocation function */
1437 void (*xFree
)(void*); /* Free a prior allocation */
1438 void *(*xRealloc
)(void*,int); /* Resize an allocation */
1439 int (*xSize
)(void*); /* Return the size of an allocation */
1440 int (*xRoundup
)(int); /* Round up request size to allocation size */
1441 int (*xInit
)(void*); /* Initialize the memory allocator */
1442 void (*xShutdown
)(void*); /* Deinitialize the memory allocator */
1443 void *pAppData
; /* Argument to xInit() and xShutdown() */
1447 ** CAPI3REF: Configuration Options
1448 ** KEYWORDS: {configuration option}
1450 ** These constants are the available integer configuration options that
1451 ** can be passed as the first argument to the [sqlite3_config()] interface.
1453 ** New configuration options may be added in future releases of SQLite.
1454 ** Existing configuration options might be discontinued. Applications
1455 ** should check the return code from [sqlite3_config()] to make sure that
1456 ** the call worked. The [sqlite3_config()] interface will return a
1457 ** non-zero [error code] if a discontinued or unsupported configuration option
1461 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1462 ** <dd>There are no arguments to this option. ^This option sets the
1463 ** [threading mode] to Single-thread. In other words, it disables
1464 ** all mutexing and puts SQLite into a mode where it can only be used
1465 ** by a single thread. ^If SQLite is compiled with
1466 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1467 ** it is not possible to change the [threading mode] from its default
1468 ** value of Single-thread and so [sqlite3_config()] will return
1469 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1470 ** configuration option.</dd>
1472 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1473 ** <dd>There are no arguments to this option. ^This option sets the
1474 ** [threading mode] to Multi-thread. In other words, it disables
1475 ** mutexing on [database connection] and [prepared statement] objects.
1476 ** The application is responsible for serializing access to
1477 ** [database connections] and [prepared statements]. But other mutexes
1478 ** are enabled so that SQLite will be safe to use in a multi-threaded
1479 ** environment as long as no two threads attempt to use the same
1480 ** [database connection] at the same time. ^If SQLite is compiled with
1481 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1482 ** it is not possible to set the Multi-thread [threading mode] and
1483 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1484 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1486 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1487 ** <dd>There are no arguments to this option. ^This option sets the
1488 ** [threading mode] to Serialized. In other words, this option enables
1489 ** all mutexes including the recursive
1490 ** mutexes on [database connection] and [prepared statement] objects.
1491 ** In this mode (which is the default when SQLite is compiled with
1492 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1493 ** to [database connections] and [prepared statements] so that the
1494 ** application is free to use the same [database connection] or the
1495 ** same [prepared statement] in different threads at the same time.
1496 ** ^If SQLite is compiled with
1497 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1498 ** it is not possible to set the Serialized [threading mode] and
1499 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1500 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1502 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1503 ** <dd> ^(This option takes a single argument which is a pointer to an
1504 ** instance of the [sqlite3_mem_methods] structure. The argument specifies
1505 ** alternative low-level memory allocation routines to be used in place of
1506 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1507 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1508 ** before the [sqlite3_config()] call returns.</dd>
1510 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1511 ** <dd> ^(This option takes a single argument which is a pointer to an
1512 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods]
1513 ** structure is filled with the currently defined memory allocation routines.)^
1514 ** This option can be used to overload the default memory allocation
1515 ** routines with a wrapper that simulations memory allocation failure or
1516 ** tracks memory usage, for example. </dd>
1518 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1519 ** <dd> ^This option takes single argument of type int, interpreted as a
1520 ** boolean, which enables or disables the collection of memory allocation
1521 ** statistics. ^(When memory allocation statistics are disabled, the
1522 ** following SQLite interfaces become non-operational:
1524 ** <li> [sqlite3_memory_used()]
1525 ** <li> [sqlite3_memory_highwater()]
1526 ** <li> [sqlite3_soft_heap_limit64()]
1527 ** <li> [sqlite3_status()]
1529 ** ^Memory allocation statistics are enabled by default unless SQLite is
1530 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1531 ** allocation statistics are disabled by default.
1534 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1535 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1536 ** scratch memory. There are three arguments: A pointer an 8-byte
1537 ** aligned memory buffer from which the scratch allocations will be
1538 ** drawn, the size of each scratch allocation (sz),
1539 ** and the maximum number of scratch allocations (N). The sz
1540 ** argument must be a multiple of 16.
1541 ** The first argument must be a pointer to an 8-byte aligned buffer
1542 ** of at least sz*N bytes of memory.
1543 ** ^SQLite will use no more than two scratch buffers per thread. So
1544 ** N should be set to twice the expected maximum number of threads.
1545 ** ^SQLite will never require a scratch buffer that is more than 6
1546 ** times the database page size. ^If SQLite needs needs additional
1547 ** scratch memory beyond what is provided by this configuration option, then
1548 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
1550 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1551 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1552 ** the database page cache with the default page cache implementation.
1553 ** This configuration should not be used if an application-define page
1554 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option.
1555 ** There are three arguments to this option: A pointer to 8-byte aligned
1556 ** memory, the size of each page buffer (sz), and the number of pages (N).
1557 ** The sz argument should be the size of the largest database page
1558 ** (a power of two between 512 and 32768) plus a little extra for each
1559 ** page header. ^The page header size is 20 to 40 bytes depending on
1560 ** the host architecture. ^It is harmless, apart from the wasted memory,
1561 ** to make sz a little too large. The first
1562 ** argument should point to an allocation of at least sz*N bytes of memory.
1563 ** ^SQLite will use the memory provided by the first argument to satisfy its
1564 ** memory needs for the first N pages that it adds to cache. ^If additional
1565 ** page cache memory is needed beyond what is provided by this option, then
1566 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
1567 ** The pointer in the first argument must
1568 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite
1569 ** will be undefined.</dd>
1571 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1572 ** <dd> ^This option specifies a static memory buffer that SQLite will use
1573 ** for all of its dynamic memory allocation needs beyond those provided
1574 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
1575 ** There are three arguments: An 8-byte aligned pointer to the memory,
1576 ** the number of bytes in the memory buffer, and the minimum allocation size.
1577 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1578 ** to using its default memory allocator (the system malloc() implementation),
1579 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1580 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
1581 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
1582 ** allocator is engaged to handle all of SQLites memory allocation needs.
1583 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1584 ** boundary or subsequent behavior of SQLite will be undefined.
1585 ** The minimum allocation size is capped at 2**12. Reasonable values
1586 ** for the minimum allocation size are 2**5 through 2**8.</dd>
1588 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1589 ** <dd> ^(This option takes a single argument which is a pointer to an
1590 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies
1591 ** alternative low-level mutex routines to be used in place
1592 ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the
1593 ** content of the [sqlite3_mutex_methods] structure before the call to
1594 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1595 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1596 ** the entire mutexing subsystem is omitted from the build and hence calls to
1597 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1598 ** return [SQLITE_ERROR].</dd>
1600 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1601 ** <dd> ^(This option takes a single argument which is a pointer to an
1602 ** instance of the [sqlite3_mutex_methods] structure. The
1603 ** [sqlite3_mutex_methods]
1604 ** structure is filled with the currently defined mutex routines.)^
1605 ** This option can be used to overload the default mutex allocation
1606 ** routines with a wrapper used to track mutex usage for performance
1607 ** profiling or testing, for example. ^If SQLite is compiled with
1608 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1609 ** the entire mutexing subsystem is omitted from the build and hence calls to
1610 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1611 ** return [SQLITE_ERROR].</dd>
1613 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1614 ** <dd> ^(This option takes two arguments that determine the default
1615 ** memory allocation for the lookaside memory allocator on each
1616 ** [database connection]. The first argument is the
1617 ** size of each lookaside buffer slot and the second is the number of
1618 ** slots allocated to each database connection.)^ ^(This option sets the
1619 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1620 ** verb to [sqlite3_db_config()] can be used to change the lookaside
1621 ** configuration on individual connections.)^ </dd>
1623 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1624 ** <dd> ^(This option takes a single argument which is a pointer to
1625 ** an [sqlite3_pcache_methods2] object. This object specifies the interface
1626 ** to a custom page cache implementation.)^ ^SQLite makes a copy of the
1627 ** object and uses it for page cache memory allocations.</dd>
1629 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1630 ** <dd> ^(This option takes a single argument which is a pointer to an
1631 ** [sqlite3_pcache_methods2] object. SQLite copies of the current
1632 ** page cache implementation into that object.)^ </dd>
1634 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1635 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1636 ** global [error log].
1637 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1638 ** function with a call signature of void(*)(void*,int,const char*),
1639 ** and a pointer to void. ^If the function pointer is not NULL, it is
1640 ** invoked by [sqlite3_log()] to process each logging event. ^If the
1641 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1642 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1643 ** passed through as the first parameter to the application-defined logger
1644 ** function whenever that function is invoked. ^The second parameter to
1645 ** the logger function is a copy of the first parameter to the corresponding
1646 ** [sqlite3_log()] call and is intended to be a [result code] or an
1647 ** [extended result code]. ^The third parameter passed to the logger is
1648 ** log message after formatting via [sqlite3_snprintf()].
1649 ** The SQLite logging interface is not reentrant; the logger function
1650 ** supplied by the application must not invoke any SQLite interface.
1651 ** In a multi-threaded application, the application-defined logger
1652 ** function must be threadsafe. </dd>
1654 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1655 ** <dd>^(This option takes a single argument of type int. If non-zero, then
1656 ** URI handling is globally enabled. If the parameter is zero, then URI handling
1657 ** is globally disabled.)^ ^If URI handling is globally enabled, all filenames
1658 ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or
1659 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1660 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1661 ** connection is opened. ^If it is globally disabled, filenames are
1662 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1663 ** database connection is opened. ^(By default, URI handling is globally
1664 ** disabled. The default value may be changed by compiling with the
1665 ** [SQLITE_USE_URI] symbol defined.)^
1667 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1668 ** <dd>^This option takes a single integer argument which is interpreted as
1669 ** a boolean in order to enable or disable the use of covering indices for
1670 ** full table scans in the query optimizer. ^The default setting is determined
1671 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1672 ** if that compile-time option is omitted.
1673 ** The ability to disable the use of covering indices for full table scans
1674 ** is because some incorrectly coded legacy applications might malfunction
1675 ** when the optimization is enabled. Providing the ability to
1676 ** disable the optimization allows the older, buggy application code to work
1677 ** without change even with newer versions of SQLite.
1679 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1680 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1681 ** <dd> These options are obsolete and should not be used by new code.
1682 ** They are retained for backwards compatibility but are now no-ops.
1685 ** [[SQLITE_CONFIG_SQLLOG]]
1686 ** <dt>SQLITE_CONFIG_SQLLOG
1687 ** <dd>This option is only available if sqlite is compiled with the
1688 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1689 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1690 ** The second should be of type (void*). The callback is invoked by the library
1691 ** in three separate circumstances, identified by the value passed as the
1692 ** fourth parameter. If the fourth parameter is 0, then the database connection
1693 ** passed as the second argument has just been opened. The third argument
1694 ** points to a buffer containing the name of the main database file. If the
1695 ** fourth parameter is 1, then the SQL statement that the third parameter
1696 ** points to has just been executed. Or, if the fourth parameter is 2, then
1697 ** the connection being passed as the second parameter is being closed. The
1698 ** third parameter is passed NULL In this case. An example of using this
1699 ** configuration option can be seen in the "test_sqllog.c" source file in
1700 ** the canonical SQLite source tree.</dd>
1702 ** [[SQLITE_CONFIG_MMAP_SIZE]]
1703 ** <dt>SQLITE_CONFIG_MMAP_SIZE
1704 ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1705 ** that are the default mmap size limit (the default setting for
1706 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1707 ** ^The default setting can be overridden by each database connection using
1708 ** either the [PRAGMA mmap_size] command, or by using the
1709 ** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size
1710 ** cannot be changed at run-time. Nor may the maximum allowed mmap size
1711 ** exceed the compile-time maximum mmap size set by the
1712 ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1713 ** ^If either argument to this option is negative, then that argument is
1714 ** changed to its compile-time default.
1716 ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
1717 ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
1718 ** <dd>^This option is only available if SQLite is compiled for Windows
1719 ** with the [SQLITE_WIN32_MALLOC] pre-processor macro defined.
1720 ** SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1721 ** that specifies the maximum size of the created heap.
1724 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1725 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1726 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1727 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1728 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1729 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */
1730 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1731 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1732 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1733 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1734 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1735 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1736 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1737 #define SQLITE_CONFIG_PCACHE 14 /* no-op */
1738 #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
1739 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
1740 #define SQLITE_CONFIG_URI 17 /* int */
1741 #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
1742 #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
1743 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
1744 #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
1745 #define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
1746 #define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
1749 ** CAPI3REF: Database Connection Configuration Options
1751 ** These constants are the available integer configuration options that
1752 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1754 ** New configuration options may be added in future releases of SQLite.
1755 ** Existing configuration options might be discontinued. Applications
1756 ** should check the return code from [sqlite3_db_config()] to make sure that
1757 ** the call worked. ^The [sqlite3_db_config()] interface will return a
1758 ** non-zero [error code] if a discontinued or unsupported configuration option
1762 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1763 ** <dd> ^This option takes three additional arguments that determine the
1764 ** [lookaside memory allocator] configuration for the [database connection].
1765 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1766 ** pointer to a memory buffer to use for lookaside memory.
1767 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1768 ** may be NULL in which case SQLite will allocate the
1769 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1770 ** size of each lookaside buffer slot. ^The third argument is the number of
1771 ** slots. The size of the buffer in the first argument must be greater than
1772 ** or equal to the product of the second and third arguments. The buffer
1773 ** must be aligned to an 8-byte boundary. ^If the second argument to
1774 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1775 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
1776 ** configuration for a database connection can only be changed when that
1777 ** connection is not currently using lookaside memory, or in other words
1778 ** when the "current value" returned by
1779 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1780 ** Any attempt to change the lookaside memory configuration when lookaside
1781 ** memory is in use leaves the configuration unchanged and returns
1782 ** [SQLITE_BUSY].)^</dd>
1784 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1785 ** <dd> ^This option is used to enable or disable the enforcement of
1786 ** [foreign key constraints]. There should be two additional arguments.
1787 ** The first argument is an integer which is 0 to disable FK enforcement,
1788 ** positive to enable FK enforcement or negative to leave FK enforcement
1789 ** unchanged. The second parameter is a pointer to an integer into which
1790 ** is written 0 or 1 to indicate whether FK enforcement is off or on
1791 ** following this call. The second parameter may be a NULL pointer, in
1792 ** which case the FK enforcement setting is not reported back. </dd>
1794 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1795 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1796 ** There should be two additional arguments.
1797 ** The first argument is an integer which is 0 to disable triggers,
1798 ** positive to enable triggers or negative to leave the setting unchanged.
1799 ** The second parameter is a pointer to an integer into which
1800 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
1801 ** following this call. The second parameter may be a NULL pointer, in
1802 ** which case the trigger setting is not reported back. </dd>
1806 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
1807 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
1808 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
1812 ** CAPI3REF: Enable Or Disable Extended Result Codes
1814 ** ^The sqlite3_extended_result_codes() routine enables or disables the
1815 ** [extended result codes] feature of SQLite. ^The extended result
1816 ** codes are disabled by default for historical compatibility.
1818 SQLITE_API
int sqlite3_extended_result_codes(sqlite3
*, int onoff
);
1821 ** CAPI3REF: Last Insert Rowid
1823 ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
1824 ** has a unique 64-bit signed
1825 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1826 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1827 ** names are not also used by explicitly declared columns. ^If
1828 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
1829 ** is another alias for the rowid.
1831 ** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the
1832 ** most recent successful [INSERT] into a rowid table or [virtual table]
1833 ** on database connection D.
1834 ** ^Inserts into [WITHOUT ROWID] tables are not recorded.
1835 ** ^If no successful [INSERT]s into rowid tables
1836 ** have ever occurred on the database connection D,
1837 ** then sqlite3_last_insert_rowid(D) returns zero.
1839 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
1840 ** method, then this routine will return the [rowid] of the inserted
1841 ** row as long as the trigger or virtual table method is running.
1842 ** But once the trigger or virtual table method ends, the value returned
1843 ** by this routine reverts to what it was before the trigger or virtual
1844 ** table method began.)^
1846 ** ^An [INSERT] that fails due to a constraint violation is not a
1847 ** successful [INSERT] and does not change the value returned by this
1848 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1849 ** and INSERT OR ABORT make no changes to the return value of this
1850 ** routine when their insertion fails. ^(When INSERT OR REPLACE
1851 ** encounters a constraint violation, it does not fail. The
1852 ** INSERT continues to completion after deleting rows that caused
1853 ** the constraint problem so INSERT OR REPLACE will always change
1854 ** the return value of this interface.)^
1856 ** ^For the purposes of this routine, an [INSERT] is considered to
1857 ** be successful even if it is subsequently rolled back.
1859 ** This function is accessible to SQL statements via the
1860 ** [last_insert_rowid() SQL function].
1862 ** If a separate thread performs a new [INSERT] on the same
1863 ** database connection while the [sqlite3_last_insert_rowid()]
1864 ** function is running and thus changes the last insert [rowid],
1865 ** then the value returned by [sqlite3_last_insert_rowid()] is
1866 ** unpredictable and might not equal either the old or the new
1867 ** last insert [rowid].
1869 SQLITE_API sqlite3_int64
sqlite3_last_insert_rowid(sqlite3
*);
1872 ** CAPI3REF: Count The Number Of Rows Modified
1874 ** ^This function returns the number of database rows that were changed
1875 ** or inserted or deleted by the most recently completed SQL statement
1876 ** on the [database connection] specified by the first parameter.
1877 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
1878 ** or [DELETE] statement are counted. Auxiliary changes caused by
1879 ** triggers or [foreign key actions] are not counted.)^ Use the
1880 ** [sqlite3_total_changes()] function to find the total number of changes
1881 ** including changes caused by triggers and foreign key actions.
1883 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
1884 ** are not counted. Only real table changes are counted.
1886 ** ^(A "row change" is a change to a single row of a single table
1887 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that
1888 ** are changed as side effects of [REPLACE] constraint resolution,
1889 ** rollback, ABORT processing, [DROP TABLE], or by any other
1890 ** mechanisms do not count as direct row changes.)^
1892 ** A "trigger context" is a scope of execution that begins and
1893 ** ends with the script of a [CREATE TRIGGER | trigger].
1894 ** Most SQL statements are
1895 ** evaluated outside of any trigger. This is the "top level"
1896 ** trigger context. If a trigger fires from the top level, a
1897 ** new trigger context is entered for the duration of that one
1898 ** trigger. Subtriggers create subcontexts for their duration.
1900 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
1901 ** not create a new trigger context.
1903 ** ^This function returns the number of direct row changes in the
1904 ** most recent INSERT, UPDATE, or DELETE statement within the same
1907 ** ^Thus, when called from the top level, this function returns the
1908 ** number of changes in the most recent INSERT, UPDATE, or DELETE
1909 ** that also occurred at the top level. ^(Within the body of a trigger,
1910 ** the sqlite3_changes() interface can be called to find the number of
1911 ** changes in the most recently completed INSERT, UPDATE, or DELETE
1912 ** statement within the body of the same trigger.
1913 ** However, the number returned does not include changes
1914 ** caused by subtriggers since those have their own context.)^
1916 ** See also the [sqlite3_total_changes()] interface, the
1917 ** [count_changes pragma], and the [changes() SQL function].
1919 ** If a separate thread makes changes on the same database connection
1920 ** while [sqlite3_changes()] is running then the value returned
1921 ** is unpredictable and not meaningful.
1923 SQLITE_API
int sqlite3_changes(sqlite3
*);
1926 ** CAPI3REF: Total Number Of Rows Modified
1928 ** ^This function returns the number of row changes caused by [INSERT],
1929 ** [UPDATE] or [DELETE] statements since the [database connection] was opened.
1930 ** ^(The count returned by sqlite3_total_changes() includes all changes
1931 ** from all [CREATE TRIGGER | trigger] contexts and changes made by
1932 ** [foreign key actions]. However,
1933 ** the count does not include changes used to implement [REPLACE] constraints,
1934 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The
1935 ** count does not include rows of views that fire an [INSTEAD OF trigger],
1936 ** though if the INSTEAD OF trigger makes changes of its own, those changes
1938 ** ^The sqlite3_total_changes() function counts the changes as soon as
1939 ** the statement that makes them is completed (when the statement handle
1940 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
1942 ** See also the [sqlite3_changes()] interface, the
1943 ** [count_changes pragma], and the [total_changes() SQL function].
1945 ** If a separate thread makes changes on the same database connection
1946 ** while [sqlite3_total_changes()] is running then the value
1947 ** returned is unpredictable and not meaningful.
1949 SQLITE_API
int sqlite3_total_changes(sqlite3
*);
1952 ** CAPI3REF: Interrupt A Long-Running Query
1954 ** ^This function causes any pending database operation to abort and
1955 ** return at its earliest opportunity. This routine is typically
1956 ** called in response to a user action such as pressing "Cancel"
1957 ** or Ctrl-C where the user wants a long query operation to halt
1960 ** ^It is safe to call this routine from a thread different from the
1961 ** thread that is currently running the database operation. But it
1962 ** is not safe to call this routine with a [database connection] that
1963 ** is closed or might close before sqlite3_interrupt() returns.
1965 ** ^If an SQL operation is very nearly finished at the time when
1966 ** sqlite3_interrupt() is called, then it might not have an opportunity
1967 ** to be interrupted and might continue to completion.
1969 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
1970 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
1971 ** that is inside an explicit transaction, then the entire transaction
1972 ** will be rolled back automatically.
1974 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
1975 ** SQL statements on [database connection] D complete. ^Any new SQL statements
1976 ** that are started after the sqlite3_interrupt() call and before the
1977 ** running statements reaches zero are interrupted as if they had been
1978 ** running prior to the sqlite3_interrupt() call. ^New SQL statements
1979 ** that are started after the running statement count reaches zero are
1980 ** not effected by the sqlite3_interrupt().
1981 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
1982 ** SQL statements is a no-op and has no effect on SQL statements
1983 ** that are started after the sqlite3_interrupt() call returns.
1985 ** If the database connection closes while [sqlite3_interrupt()]
1986 ** is running then bad things will likely happen.
1988 SQLITE_API
void sqlite3_interrupt(sqlite3
*);
1991 ** CAPI3REF: Determine If An SQL Statement Is Complete
1993 ** These routines are useful during command-line input to determine if the
1994 ** currently entered text seems to form a complete SQL statement or
1995 ** if additional input is needed before sending the text into
1996 ** SQLite for parsing. ^These routines return 1 if the input string
1997 ** appears to be a complete SQL statement. ^A statement is judged to be
1998 ** complete if it ends with a semicolon token and is not a prefix of a
1999 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
2000 ** string literals or quoted identifier names or comments are not
2001 ** independent tokens (they are part of the token in which they are
2002 ** embedded) and thus do not count as a statement terminator. ^Whitespace
2003 ** and comments that follow the final semicolon are ignored.
2005 ** ^These routines return 0 if the statement is incomplete. ^If a
2006 ** memory allocation fails, then SQLITE_NOMEM is returned.
2008 ** ^These routines do not parse the SQL statements thus
2009 ** will not detect syntactically incorrect SQL.
2011 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2012 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2013 ** automatically by sqlite3_complete16(). If that initialization fails,
2014 ** then the return value from sqlite3_complete16() will be non-zero
2015 ** regardless of whether or not the input SQL is complete.)^
2017 ** The input to [sqlite3_complete()] must be a zero-terminated
2020 ** The input to [sqlite3_complete16()] must be a zero-terminated
2021 ** UTF-16 string in native byte order.
2023 SQLITE_API
int sqlite3_complete(const char *sql
);
2024 SQLITE_API
int sqlite3_complete16(const void *sql
);
2027 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2029 ** ^This routine sets a callback function that might be invoked whenever
2030 ** an attempt is made to open a database table that another thread
2031 ** or process has locked.
2033 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
2034 ** is returned immediately upon encountering the lock. ^If the busy callback
2035 ** is not NULL, then the callback might be invoked with two arguments.
2037 ** ^The first argument to the busy handler is a copy of the void* pointer which
2038 ** is the third argument to sqlite3_busy_handler(). ^The second argument to
2039 ** the busy handler callback is the number of times that the busy handler has
2040 ** been invoked for this locking event. ^If the
2041 ** busy callback returns 0, then no additional attempts are made to
2042 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
2043 ** ^If the callback returns non-zero, then another attempt
2044 ** is made to open the database for reading and the cycle repeats.
2046 ** The presence of a busy handler does not guarantee that it will be invoked
2047 ** when there is lock contention. ^If SQLite determines that invoking the busy
2048 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2049 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
2050 ** Consider a scenario where one process is holding a read lock that
2051 ** it is trying to promote to a reserved lock and
2052 ** a second process is holding a reserved lock that it is trying
2053 ** to promote to an exclusive lock. The first process cannot proceed
2054 ** because it is blocked by the second and the second process cannot
2055 ** proceed because it is blocked by the first. If both processes
2056 ** invoke the busy handlers, neither will make any progress. Therefore,
2057 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2058 ** will induce the first process to release its read lock and allow
2059 ** the second process to proceed.
2061 ** ^The default busy callback is NULL.
2063 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
2064 ** when SQLite is in the middle of a large transaction where all the
2065 ** changes will not fit into the in-memory cache. SQLite will
2066 ** already hold a RESERVED lock on the database file, but it needs
2067 ** to promote this lock to EXCLUSIVE so that it can spill cache
2068 ** pages into the database file without harm to concurrent
2069 ** readers. ^If it is unable to promote the lock, then the in-memory
2070 ** cache will be left in an inconsistent state and so the error
2071 ** code is promoted from the relatively benign [SQLITE_BUSY] to
2072 ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion
2073 ** forces an automatic rollback of the changes. See the
2074 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
2075 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
2076 ** this is important.
2078 ** ^(There can only be a single busy handler defined for each
2079 ** [database connection]. Setting a new busy handler clears any
2080 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
2081 ** will also set or clear the busy handler.
2083 ** The busy callback should not take any actions which modify the
2084 ** database connection that invoked the busy handler. Any such actions
2085 ** result in undefined behavior.
2087 ** A busy handler must not close the database connection
2088 ** or [prepared statement] that invoked the busy handler.
2090 SQLITE_API
int sqlite3_busy_handler(sqlite3
*, int(*)(void*,int), void*);
2093 ** CAPI3REF: Set A Busy Timeout
2095 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2096 ** for a specified amount of time when a table is locked. ^The handler
2097 ** will sleep multiple times until at least "ms" milliseconds of sleeping
2098 ** have accumulated. ^After at least "ms" milliseconds of sleeping,
2099 ** the handler returns 0 which causes [sqlite3_step()] to return
2100 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
2102 ** ^Calling this routine with an argument less than or equal to zero
2103 ** turns off all busy handlers.
2105 ** ^(There can only be a single busy handler for a particular
2106 ** [database connection] any any given moment. If another busy handler
2107 ** was defined (using [sqlite3_busy_handler()]) prior to calling
2108 ** this routine, that other busy handler is cleared.)^
2110 SQLITE_API
int sqlite3_busy_timeout(sqlite3
*, int ms
);
2113 ** CAPI3REF: Convenience Routines For Running Queries
2115 ** This is a legacy interface that is preserved for backwards compatibility.
2116 ** Use of this interface is not recommended.
2118 ** Definition: A <b>result table</b> is memory data structure created by the
2119 ** [sqlite3_get_table()] interface. A result table records the
2120 ** complete query results from one or more queries.
2122 ** The table conceptually has a number of rows and columns. But
2123 ** these numbers are not part of the result table itself. These
2124 ** numbers are obtained separately. Let N be the number of rows
2125 ** and M be the number of columns.
2127 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2128 ** There are (N+1)*M elements in the array. The first M pointers point
2129 ** to zero-terminated strings that contain the names of the columns.
2130 ** The remaining entries all point to query results. NULL values result
2131 ** in NULL pointers. All other values are in their UTF-8 zero-terminated
2132 ** string representation as returned by [sqlite3_column_text()].
2134 ** A result table might consist of one or more memory allocations.
2135 ** It is not safe to pass a result table directly to [sqlite3_free()].
2136 ** A result table should be deallocated using [sqlite3_free_table()].
2138 ** ^(As an example of the result table format, suppose a query result
2141 ** <blockquote><pre>
2143 ** -----------------------
2147 ** </pre></blockquote>
2149 ** There are two column (M==2) and three rows (N==3). Thus the
2150 ** result table has 8 entries. Suppose the result table is stored
2151 ** in an array names azResult. Then azResult holds this content:
2153 ** <blockquote><pre>
2154 ** azResult[0] = "Name";
2155 ** azResult[1] = "Age";
2156 ** azResult[2] = "Alice";
2157 ** azResult[3] = "43";
2158 ** azResult[4] = "Bob";
2159 ** azResult[5] = "28";
2160 ** azResult[6] = "Cindy";
2161 ** azResult[7] = "21";
2162 ** </pre></blockquote>)^
2164 ** ^The sqlite3_get_table() function evaluates one or more
2165 ** semicolon-separated SQL statements in the zero-terminated UTF-8
2166 ** string of its 2nd parameter and returns a result table to the
2167 ** pointer given in its 3rd parameter.
2169 ** After the application has finished with the result from sqlite3_get_table(),
2170 ** it must pass the result table pointer to sqlite3_free_table() in order to
2171 ** release the memory that was malloced. Because of the way the
2172 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2173 ** function must not try to call [sqlite3_free()] directly. Only
2174 ** [sqlite3_free_table()] is able to release the memory properly and safely.
2176 ** The sqlite3_get_table() interface is implemented as a wrapper around
2177 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
2178 ** to any internal data structures of SQLite. It uses only the public
2179 ** interface defined here. As a consequence, errors that occur in the
2180 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2181 ** reflected in subsequent calls to [sqlite3_errcode()] or
2182 ** [sqlite3_errmsg()].
2184 SQLITE_API
int sqlite3_get_table(
2185 sqlite3
*db
, /* An open database */
2186 const char *zSql
, /* SQL to be evaluated */
2187 char ***pazResult
, /* Results of the query */
2188 int *pnRow
, /* Number of result rows written here */
2189 int *pnColumn
, /* Number of result columns written here */
2190 char **pzErrmsg
/* Error msg written here */
2192 SQLITE_API
void sqlite3_free_table(char **result
);
2195 ** CAPI3REF: Formatted String Printing Functions
2197 ** These routines are work-alikes of the "printf()" family of functions
2198 ** from the standard C library.
2200 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2201 ** results into memory obtained from [sqlite3_malloc()].
2202 ** The strings returned by these two routines should be
2203 ** released by [sqlite3_free()]. ^Both routines return a
2204 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2205 ** memory to hold the resulting string.
2207 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2208 ** the standard C library. The result is written into the
2209 ** buffer supplied as the second parameter whose size is given by
2210 ** the first parameter. Note that the order of the
2211 ** first two parameters is reversed from snprintf().)^ This is an
2212 ** historical accident that cannot be fixed without breaking
2213 ** backwards compatibility. ^(Note also that sqlite3_snprintf()
2214 ** returns a pointer to its buffer instead of the number of
2215 ** characters actually written into the buffer.)^ We admit that
2216 ** the number of characters written would be a more useful return
2217 ** value but we cannot change the implementation of sqlite3_snprintf()
2218 ** now without breaking compatibility.
2220 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2221 ** guarantees that the buffer is always zero-terminated. ^The first
2222 ** parameter "n" is the total size of the buffer, including space for
2223 ** the zero terminator. So the longest string that can be completely
2224 ** written will be n-1 characters.
2226 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2228 ** These routines all implement some additional formatting
2229 ** options that are useful for constructing SQL statements.
2230 ** All of the usual printf() formatting options apply. In addition, there
2231 ** is are "%q", "%Q", and "%z" options.
2233 ** ^(The %q option works like %s in that it substitutes a nul-terminated
2234 ** string from the argument list. But %q also doubles every '\'' character.
2235 ** %q is designed for use inside a string literal.)^ By doubling each '\''
2236 ** character it escapes that character and allows it to be inserted into
2239 ** For example, assume the string variable zText contains text as follows:
2241 ** <blockquote><pre>
2242 ** char *zText = "It's a happy day!";
2243 ** </pre></blockquote>
2245 ** One can use this text in an SQL statement as follows:
2247 ** <blockquote><pre>
2248 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2249 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2250 ** sqlite3_free(zSQL);
2251 ** </pre></blockquote>
2253 ** Because the %q format string is used, the '\'' character in zText
2254 ** is escaped and the SQL generated is as follows:
2256 ** <blockquote><pre>
2257 ** INSERT INTO table1 VALUES('It''s a happy day!')
2258 ** </pre></blockquote>
2260 ** This is correct. Had we used %s instead of %q, the generated SQL
2261 ** would have looked like this:
2263 ** <blockquote><pre>
2264 ** INSERT INTO table1 VALUES('It's a happy day!');
2265 ** </pre></blockquote>
2267 ** This second example is an SQL syntax error. As a general rule you should
2268 ** always use %q instead of %s when inserting text into a string literal.
2270 ** ^(The %Q option works like %q except it also adds single quotes around
2271 ** the outside of the total string. Additionally, if the parameter in the
2272 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2273 ** single quotes).)^ So, for example, one could say:
2275 ** <blockquote><pre>
2276 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2277 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2278 ** sqlite3_free(zSQL);
2279 ** </pre></blockquote>
2281 ** The code above will render a correct SQL statement in the zSQL
2282 ** variable even if the zText variable is a NULL pointer.
2284 ** ^(The "%z" formatting option works like "%s" but with the
2285 ** addition that after the string has been read and copied into
2286 ** the result, [sqlite3_free()] is called on the input string.)^
2288 SQLITE_API
char *sqlite3_mprintf(const char*,...);
2289 SQLITE_API
char *sqlite3_vmprintf(const char*, va_list);
2290 SQLITE_API
char *sqlite3_snprintf(int,char*,const char*, ...);
2291 SQLITE_API
char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2294 ** CAPI3REF: Memory Allocation Subsystem
2296 ** The SQLite core uses these three routines for all of its own
2297 ** internal memory allocation needs. "Core" in the previous sentence
2298 ** does not include operating-system specific VFS implementation. The
2299 ** Windows VFS uses native malloc() and free() for some operations.
2301 ** ^The sqlite3_malloc() routine returns a pointer to a block
2302 ** of memory at least N bytes in length, where N is the parameter.
2303 ** ^If sqlite3_malloc() is unable to obtain sufficient free
2304 ** memory, it returns a NULL pointer. ^If the parameter N to
2305 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2308 ** ^Calling sqlite3_free() with a pointer previously returned
2309 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2310 ** that it might be reused. ^The sqlite3_free() routine is
2311 ** a no-op if is called with a NULL pointer. Passing a NULL pointer
2312 ** to sqlite3_free() is harmless. After being freed, memory
2313 ** should neither be read nor written. Even reading previously freed
2314 ** memory might result in a segmentation fault or other severe error.
2315 ** Memory corruption, a segmentation fault, or other severe error
2316 ** might result if sqlite3_free() is called with a non-NULL pointer that
2317 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2319 ** ^(The sqlite3_realloc() interface attempts to resize a
2320 ** prior memory allocation to be at least N bytes, where N is the
2321 ** second parameter. The memory allocation to be resized is the first
2322 ** parameter.)^ ^ If the first parameter to sqlite3_realloc()
2323 ** is a NULL pointer then its behavior is identical to calling
2324 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
2325 ** ^If the second parameter to sqlite3_realloc() is zero or
2326 ** negative then the behavior is exactly the same as calling
2327 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
2328 ** ^sqlite3_realloc() returns a pointer to a memory allocation
2329 ** of at least N bytes in size or NULL if sufficient memory is unavailable.
2330 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2331 ** of the prior allocation are copied into the beginning of buffer returned
2332 ** by sqlite3_realloc() and the prior allocation is freed.
2333 ** ^If sqlite3_realloc() returns NULL, then the prior allocation
2336 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
2337 ** is always aligned to at least an 8 byte boundary, or to a
2338 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2341 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2342 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2343 ** implementation of these routines to be omitted. That capability
2344 ** is no longer provided. Only built-in memory allocators can be used.
2346 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2347 ** the system malloc() and free() directly when converting
2348 ** filenames between the UTF-8 encoding used by SQLite
2349 ** and whatever filename encoding is used by the particular Windows
2350 ** installation. Memory allocation errors were detected, but
2351 ** they were reported back as [SQLITE_CANTOPEN] or
2352 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2354 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2355 ** must be either NULL or else pointers obtained from a prior
2356 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2357 ** not yet been released.
2359 ** The application must not read or write any part of
2360 ** a block of memory after it has been released using
2361 ** [sqlite3_free()] or [sqlite3_realloc()].
2363 SQLITE_API
void *sqlite3_malloc(int);
2364 SQLITE_API
void *sqlite3_realloc(void*, int);
2365 SQLITE_API
void sqlite3_free(void*);
2368 ** CAPI3REF: Memory Allocator Statistics
2370 ** SQLite provides these two interfaces for reporting on the status
2371 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2372 ** routines, which form the built-in memory allocation subsystem.
2374 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2375 ** of memory currently outstanding (malloced but not freed).
2376 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2377 ** value of [sqlite3_memory_used()] since the high-water mark
2378 ** was last reset. ^The values returned by [sqlite3_memory_used()] and
2379 ** [sqlite3_memory_highwater()] include any overhead
2380 ** added by SQLite in its implementation of [sqlite3_malloc()],
2381 ** but not overhead added by the any underlying system library
2382 ** routines that [sqlite3_malloc()] may call.
2384 ** ^The memory high-water mark is reset to the current value of
2385 ** [sqlite3_memory_used()] if and only if the parameter to
2386 ** [sqlite3_memory_highwater()] is true. ^The value returned
2387 ** by [sqlite3_memory_highwater(1)] is the high-water mark
2388 ** prior to the reset.
2390 SQLITE_API sqlite3_int64
sqlite3_memory_used(void);
2391 SQLITE_API sqlite3_int64
sqlite3_memory_highwater(int resetFlag
);
2394 ** CAPI3REF: Pseudo-Random Number Generator
2396 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2397 ** select random [ROWID | ROWIDs] when inserting new records into a table that
2398 ** already uses the largest possible [ROWID]. The PRNG is also used for
2399 ** the build-in random() and randomblob() SQL functions. This interface allows
2400 ** applications to access the same PRNG for other purposes.
2402 ** ^A call to this routine stores N bytes of randomness into buffer P.
2403 ** ^If N is less than one, then P can be a NULL pointer.
2405 ** ^If this routine has not been previously called or if the previous
2406 ** call had N less than one, then the PRNG is seeded using randomness
2407 ** obtained from the xRandomness method of the default [sqlite3_vfs] object.
2408 ** ^If the previous call to this routine had an N of 1 or more then
2409 ** the pseudo-randomness is generated
2410 ** internally and without recourse to the [sqlite3_vfs] xRandomness
2413 SQLITE_API
void sqlite3_randomness(int N
, void *P
);
2416 ** CAPI3REF: Compile-Time Authorization Callbacks
2418 ** ^This routine registers an authorizer callback with a particular
2419 ** [database connection], supplied in the first argument.
2420 ** ^The authorizer callback is invoked as SQL statements are being compiled
2421 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2422 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various
2423 ** points during the compilation process, as logic is being created
2424 ** to perform various actions, the authorizer callback is invoked to
2425 ** see if those actions are allowed. ^The authorizer callback should
2426 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2427 ** specific action but allow the SQL statement to continue to be
2428 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2429 ** rejected with an error. ^If the authorizer callback returns
2430 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2431 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2432 ** the authorizer will fail with an error message.
2434 ** When the callback returns [SQLITE_OK], that means the operation
2435 ** requested is ok. ^When the callback returns [SQLITE_DENY], the
2436 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2437 ** authorizer will fail with an error message explaining that
2438 ** access is denied.
2440 ** ^The first parameter to the authorizer callback is a copy of the third
2441 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2442 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2443 ** the particular action to be authorized. ^The third through sixth parameters
2444 ** to the callback are zero-terminated strings that contain additional
2445 ** details about the action to be authorized.
2447 ** ^If the action code is [SQLITE_READ]
2448 ** and the callback returns [SQLITE_IGNORE] then the
2449 ** [prepared statement] statement is constructed to substitute
2450 ** a NULL value in place of the table column that would have
2451 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2452 ** return can be used to deny an untrusted user access to individual
2453 ** columns of a table.
2454 ** ^If the action code is [SQLITE_DELETE] and the callback returns
2455 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2456 ** [truncate optimization] is disabled and all rows are deleted individually.
2458 ** An authorizer is used when [sqlite3_prepare | preparing]
2459 ** SQL statements from an untrusted source, to ensure that the SQL statements
2460 ** do not try to access data they are not allowed to see, or that they do not
2461 ** try to execute malicious statements that damage the database. For
2462 ** example, an application may allow a user to enter arbitrary
2463 ** SQL queries for evaluation by a database. But the application does
2464 ** not want the user to be able to make arbitrary changes to the
2465 ** database. An authorizer could then be put in place while the
2466 ** user-entered SQL is being [sqlite3_prepare | prepared] that
2467 ** disallows everything except [SELECT] statements.
2469 ** Applications that need to process SQL from untrusted sources
2470 ** might also consider lowering resource limits using [sqlite3_limit()]
2471 ** and limiting database size using the [max_page_count] [PRAGMA]
2472 ** in addition to using an authorizer.
2474 ** ^(Only a single authorizer can be in place on a database connection
2475 ** at a time. Each call to sqlite3_set_authorizer overrides the
2476 ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2477 ** The authorizer is disabled by default.
2479 ** The authorizer callback must not do anything that will modify
2480 ** the database connection that invoked the authorizer callback.
2481 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2482 ** database connections for the meaning of "modify" in this paragraph.
2484 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2485 ** statement might be re-prepared during [sqlite3_step()] due to a
2486 ** schema change. Hence, the application should ensure that the
2487 ** correct authorizer callback remains in place during the [sqlite3_step()].
2489 ** ^Note that the authorizer callback is invoked only during
2490 ** [sqlite3_prepare()] or its variants. Authorization is not
2491 ** performed during statement evaluation in [sqlite3_step()], unless
2492 ** as stated in the previous paragraph, sqlite3_step() invokes
2493 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2495 SQLITE_API
int sqlite3_set_authorizer(
2497 int (*xAuth
)(void*,int,const char*,const char*,const char*,const char*),
2502 ** CAPI3REF: Authorizer Return Codes
2504 ** The [sqlite3_set_authorizer | authorizer callback function] must
2505 ** return either [SQLITE_OK] or one of these two constants in order
2506 ** to signal SQLite whether or not the action is permitted. See the
2507 ** [sqlite3_set_authorizer | authorizer documentation] for additional
2510 ** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code]
2511 ** from the [sqlite3_vtab_on_conflict()] interface.
2513 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */
2514 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
2517 ** CAPI3REF: Authorizer Action Codes
2519 ** The [sqlite3_set_authorizer()] interface registers a callback function
2520 ** that is invoked to authorize certain SQL statement actions. The
2521 ** second parameter to the callback is an integer code that specifies
2522 ** what action is being authorized. These are the integer action codes that
2523 ** the authorizer callback may be passed.
2525 ** These action code values signify what kind of operation is to be
2526 ** authorized. The 3rd and 4th parameters to the authorization
2527 ** callback function will be parameters or NULL depending on which of these
2528 ** codes is used as the second parameter. ^(The 5th parameter to the
2529 ** authorizer callback is the name of the database ("main", "temp",
2530 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2531 ** is the name of the inner-most trigger or view that is responsible for
2532 ** the access attempt or NULL if this access attempt is directly from
2533 ** top-level SQL code.
2535 /******************************************* 3rd ************ 4th ***********/
2536 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
2537 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
2538 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
2539 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
2540 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
2541 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
2542 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2543 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2544 #define SQLITE_DELETE 9 /* Table Name NULL */
2545 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2546 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2547 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2548 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2549 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2550 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2551 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2552 #define SQLITE_DROP_VIEW 17 /* View Name NULL */
2553 #define SQLITE_INSERT 18 /* Table Name NULL */
2554 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2555 #define SQLITE_READ 20 /* Table Name Column Name */
2556 #define SQLITE_SELECT 21 /* NULL NULL */
2557 #define SQLITE_TRANSACTION 22 /* Operation NULL */
2558 #define SQLITE_UPDATE 23 /* Table Name Column Name */
2559 #define SQLITE_ATTACH 24 /* Filename NULL */
2560 #define SQLITE_DETACH 25 /* Database Name NULL */
2561 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2562 #define SQLITE_REINDEX 27 /* Index Name NULL */
2563 #define SQLITE_ANALYZE 28 /* Table Name NULL */
2564 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2565 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2566 #define SQLITE_FUNCTION 31 /* NULL Function Name */
2567 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2568 #define SQLITE_COPY 0 /* No longer used */
2569 #define SQLITE_RECURSIVE 33 /* NULL NULL */
2572 ** CAPI3REF: Tracing And Profiling Functions
2574 ** These routines register callback functions that can be used for
2575 ** tracing and profiling the execution of SQL statements.
2577 ** ^The callback function registered by sqlite3_trace() is invoked at
2578 ** various times when an SQL statement is being run by [sqlite3_step()].
2579 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2580 ** SQL statement text as the statement first begins executing.
2581 ** ^(Additional sqlite3_trace() callbacks might occur
2582 ** as each triggered subprogram is entered. The callbacks for triggers
2583 ** contain a UTF-8 SQL comment that identifies the trigger.)^
2585 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2586 ** the length of [bound parameter] expansion in the output of sqlite3_trace().
2588 ** ^The callback function registered by sqlite3_profile() is invoked
2589 ** as each SQL statement finishes. ^The profile callback contains
2590 ** the original statement text and an estimate of wall-clock time
2591 ** of how long that statement took to run. ^The profile callback
2592 ** time is in units of nanoseconds, however the current implementation
2593 ** is only capable of millisecond resolution so the six least significant
2594 ** digits in the time are meaningless. Future versions of SQLite
2595 ** might provide greater resolution on the profiler callback. The
2596 ** sqlite3_profile() function is considered experimental and is
2597 ** subject to change in future versions of SQLite.
2599 SQLITE_API
void *sqlite3_trace(sqlite3
*, void(*xTrace
)(void*,const char*), void*);
2600 SQLITE_API SQLITE_EXPERIMENTAL
void *sqlite3_profile(sqlite3
*,
2601 void(*xProfile
)(void*,const char*,sqlite3_uint64
), void*);
2604 ** CAPI3REF: Query Progress Callbacks
2606 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2607 ** function X to be invoked periodically during long running calls to
2608 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2609 ** database connection D. An example use for this
2610 ** interface is to keep a GUI updated during a large query.
2612 ** ^The parameter P is passed through as the only parameter to the
2613 ** callback function X. ^The parameter N is the approximate number of
2614 ** [virtual machine instructions] that are evaluated between successive
2615 ** invocations of the callback X. ^If N is less than one then the progress
2616 ** handler is disabled.
2618 ** ^Only a single progress handler may be defined at one time per
2619 ** [database connection]; setting a new progress handler cancels the
2620 ** old one. ^Setting parameter X to NULL disables the progress handler.
2621 ** ^The progress handler is also disabled by setting N to a value less
2624 ** ^If the progress callback returns non-zero, the operation is
2625 ** interrupted. This feature can be used to implement a
2626 ** "Cancel" button on a GUI progress dialog box.
2628 ** The progress handler callback must not do anything that will modify
2629 ** the database connection that invoked the progress handler.
2630 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2631 ** database connections for the meaning of "modify" in this paragraph.
2634 SQLITE_API
void sqlite3_progress_handler(sqlite3
*, int, int(*)(void*), void*);
2637 ** CAPI3REF: Opening A New Database Connection
2639 ** ^These routines open an SQLite database file as specified by the
2640 ** filename argument. ^The filename argument is interpreted as UTF-8 for
2641 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2642 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
2643 ** returned in *ppDb, even if an error occurs. The only exception is that
2644 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2645 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2646 ** object.)^ ^(If the database is opened (and/or created) successfully, then
2647 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
2648 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2649 ** an English language description of the error following a failure of any
2650 ** of the sqlite3_open() routines.
2652 ** ^The default encoding for the database will be UTF-8 if
2653 ** sqlite3_open() or sqlite3_open_v2() is called and
2654 ** UTF-16 in the native byte order if sqlite3_open16() is used.
2656 ** Whether or not an error occurs when it is opened, resources
2657 ** associated with the [database connection] handle should be released by
2658 ** passing it to [sqlite3_close()] when it is no longer required.
2660 ** The sqlite3_open_v2() interface works like sqlite3_open()
2661 ** except that it accepts two additional parameters for additional control
2662 ** over the new database connection. ^(The flags parameter to
2663 ** sqlite3_open_v2() can take one of
2664 ** the following three values, optionally combined with the
2665 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2666 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
2669 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2670 ** <dd>The database is opened in read-only mode. If the database does not
2671 ** already exist, an error is returned.</dd>)^
2673 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2674 ** <dd>The database is opened for reading and writing if possible, or reading
2675 ** only if the file is write protected by the operating system. In either
2676 ** case the database must already exist, otherwise an error is returned.</dd>)^
2678 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2679 ** <dd>The database is opened for reading and writing, and is created if
2680 ** it does not already exist. This is the behavior that is always used for
2681 ** sqlite3_open() and sqlite3_open16().</dd>)^
2684 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
2685 ** combinations shown above optionally combined with other
2686 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
2687 ** then the behavior is undefined.
2689 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2690 ** opens in the multi-thread [threading mode] as long as the single-thread
2691 ** mode has not been set at compile-time or start-time. ^If the
2692 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2693 ** in the serialized [threading mode] unless single-thread was
2694 ** previously selected at compile-time or start-time.
2695 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2696 ** eligible to use [shared cache mode], regardless of whether or not shared
2697 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
2698 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2699 ** participate in [shared cache mode] even if it is enabled.
2701 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
2702 ** [sqlite3_vfs] object that defines the operating system interface that
2703 ** the new database connection should use. ^If the fourth parameter is
2704 ** a NULL pointer then the default [sqlite3_vfs] object is used.
2706 ** ^If the filename is ":memory:", then a private, temporary in-memory database
2707 ** is created for the connection. ^This in-memory database will vanish when
2708 ** the database connection is closed. Future versions of SQLite might
2709 ** make use of additional special filenames that begin with the ":" character.
2710 ** It is recommended that when a database filename actually does begin with
2711 ** a ":" character you should prefix the filename with a pathname such as
2712 ** "./" to avoid ambiguity.
2714 ** ^If the filename is an empty string, then a private, temporary
2715 ** on-disk database will be created. ^This private database will be
2716 ** automatically deleted as soon as the database connection is closed.
2718 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
2720 ** ^If [URI filename] interpretation is enabled, and the filename argument
2721 ** begins with "file:", then the filename is interpreted as a URI. ^URI
2722 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
2723 ** set in the fourth argument to sqlite3_open_v2(), or if it has
2724 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
2725 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
2726 ** As of SQLite version 3.7.7, URI filename interpretation is turned off
2727 ** by default, but future releases of SQLite might enable URI filename
2728 ** interpretation by default. See "[URI filenames]" for additional
2731 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
2732 ** authority, then it must be either an empty string or the string
2733 ** "localhost". ^If the authority is not an empty string or "localhost", an
2734 ** error is returned to the caller. ^The fragment component of a URI, if
2735 ** present, is ignored.
2737 ** ^SQLite uses the path component of the URI as the name of the disk file
2738 ** which contains the database. ^If the path begins with a '/' character,
2739 ** then it is interpreted as an absolute path. ^If the path does not begin
2740 ** with a '/' (meaning that the authority section is omitted from the URI)
2741 ** then the path is interpreted as a relative path.
2742 ** ^On windows, the first component of an absolute path
2743 ** is a drive specification (e.g. "C:").
2745 ** [[core URI query parameters]]
2746 ** The query component of a URI may contain parameters that are interpreted
2747 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
2748 ** SQLite interprets the following three query parameters:
2751 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
2752 ** a VFS object that provides the operating system interface that should
2753 ** be used to access the database file on disk. ^If this option is set to
2754 ** an empty string the default VFS object is used. ^Specifying an unknown
2755 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
2756 ** present, then the VFS specified by the option takes precedence over
2757 ** the value passed as the fourth parameter to sqlite3_open_v2().
2759 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
2760 ** "rwc", or "memory". Attempting to set it to any other value is
2762 ** ^If "ro" is specified, then the database is opened for read-only
2763 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
2764 ** third argument to sqlite3_open_v2(). ^If the mode option is set to
2765 ** "rw", then the database is opened for read-write (but not create)
2766 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
2767 ** been set. ^Value "rwc" is equivalent to setting both
2768 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
2769 ** set to "memory" then a pure [in-memory database] that never reads
2770 ** or writes from disk is used. ^It is an error to specify a value for
2771 ** the mode parameter that is less restrictive than that specified by
2772 ** the flags passed in the third parameter to sqlite3_open_v2().
2774 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
2775 ** "private". ^Setting it to "shared" is equivalent to setting the
2776 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
2777 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
2778 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
2779 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
2780 ** a URI filename, its value overrides any behavior requested by setting
2781 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
2784 ** ^Specifying an unknown parameter in the query component of a URI is not an
2785 ** error. Future versions of SQLite might understand additional query
2786 ** parameters. See "[query parameters with special meaning to SQLite]" for
2787 ** additional information.
2789 ** [[URI filename examples]] <h3>URI filename examples</h3>
2791 ** <table border="1" align=center cellpadding=5>
2792 ** <tr><th> URI filenames <th> Results
2793 ** <tr><td> file:data.db <td>
2794 ** Open the file "data.db" in the current directory.
2795 ** <tr><td> file:/home/fred/data.db<br>
2796 ** file:///home/fred/data.db <br>
2797 ** file://localhost/home/fred/data.db <br> <td>
2798 ** Open the database file "/home/fred/data.db".
2799 ** <tr><td> file://darkstar/home/fred/data.db <td>
2800 ** An error. "darkstar" is not a recognized authority.
2801 ** <tr><td style="white-space:nowrap">
2802 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
2803 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive
2804 ** C:. Note that the %20 escaping in this example is not strictly
2805 ** necessary - space characters can be used literally
2806 ** in URI filenames.
2807 ** <tr><td> file:data.db?mode=ro&cache=private <td>
2808 ** Open file "data.db" in the current directory for read-only access.
2809 ** Regardless of whether or not shared-cache mode is enabled by
2810 ** default, use a private cache.
2811 ** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td>
2812 ** Open file "/home/fred/data.db". Use the special VFS "unix-nolock".
2813 ** <tr><td> file:data.db?mode=readonly <td>
2814 ** An error. "readonly" is not a valid option for the "mode" parameter.
2817 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
2818 ** query components of a URI. A hexadecimal escape sequence consists of a
2819 ** percent sign - "%" - followed by exactly two hexadecimal digits
2820 ** specifying an octet value. ^Before the path or query components of a
2821 ** URI filename are interpreted, they are encoded using UTF-8 and all
2822 ** hexadecimal escape sequences replaced by a single byte containing the
2823 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
2824 ** the results are undefined.
2826 ** <b>Note to Windows users:</b> The encoding used for the filename argument
2827 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2828 ** codepage is currently defined. Filenames containing international
2829 ** characters must be converted to UTF-8 prior to passing them into
2830 ** sqlite3_open() or sqlite3_open_v2().
2832 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
2833 ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
2834 ** features that require the use of temporary files may fail.
2836 ** See also: [sqlite3_temp_directory]
2838 SQLITE_API
int sqlite3_open(
2839 const char *filename
, /* Database filename (UTF-8) */
2840 sqlite3
**ppDb
/* OUT: SQLite db handle */
2842 SQLITE_API
int sqlite3_open16(
2843 const void *filename
, /* Database filename (UTF-16) */
2844 sqlite3
**ppDb
/* OUT: SQLite db handle */
2846 SQLITE_API
int sqlite3_open_v2(
2847 const char *filename
, /* Database filename (UTF-8) */
2848 sqlite3
**ppDb
, /* OUT: SQLite db handle */
2849 int flags
, /* Flags */
2850 const char *zVfs
/* Name of VFS module to use */
2854 ** CAPI3REF: Obtain Values For URI Parameters
2856 ** These are utility routines, useful to VFS implementations, that check
2857 ** to see if a database file was a URI that contained a specific query
2858 ** parameter, and if so obtains the value of that query parameter.
2860 ** If F is the database filename pointer passed into the xOpen() method of
2861 ** a VFS implementation when the flags parameter to xOpen() has one or
2862 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
2863 ** P is the name of the query parameter, then
2864 ** sqlite3_uri_parameter(F,P) returns the value of the P
2865 ** parameter if it exists or a NULL pointer if P does not appear as a
2866 ** query parameter on F. If P is a query parameter of F
2867 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
2868 ** a pointer to an empty string.
2870 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
2871 ** parameter and returns true (1) or false (0) according to the value
2872 ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
2873 ** value of query parameter P is one of "yes", "true", or "on" in any
2874 ** case or if the value begins with a non-zero number. The
2875 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
2876 ** query parameter P is one of "no", "false", or "off" in any case or
2877 ** if the value begins with a numeric zero. If P is not a query
2878 ** parameter on F or if the value of P is does not match any of the
2879 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
2881 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
2882 ** 64-bit signed integer and returns that integer, or D if P does not
2883 ** exist. If the value of P is something other than an integer, then
2884 ** zero is returned.
2886 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
2887 ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
2888 ** is not a database file pathname pointer that SQLite passed into the xOpen
2889 ** VFS method, then the behavior of this routine is undefined and probably
2892 SQLITE_API
const char *sqlite3_uri_parameter(const char *zFilename
, const char *zParam
);
2893 SQLITE_API
int sqlite3_uri_boolean(const char *zFile
, const char *zParam
, int bDefault
);
2894 SQLITE_API sqlite3_int64
sqlite3_uri_int64(const char*, const char*, sqlite3_int64
);
2898 ** CAPI3REF: Error Codes And Messages
2900 ** ^The sqlite3_errcode() interface returns the numeric [result code] or
2901 ** [extended result code] for the most recent failed sqlite3_* API call
2902 ** associated with a [database connection]. If a prior API call failed
2903 ** but the most recent API call succeeded, the return value from
2904 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode()
2905 ** interface is the same except that it always returns the
2906 ** [extended result code] even when extended result codes are
2909 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
2910 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
2911 ** ^(Memory to hold the error message string is managed internally.
2912 ** The application does not need to worry about freeing the result.
2913 ** However, the error string might be overwritten or deallocated by
2914 ** subsequent calls to other SQLite interface functions.)^
2916 ** ^The sqlite3_errstr() interface returns the English-language text
2917 ** that describes the [result code], as UTF-8.
2918 ** ^(Memory to hold the error message string is managed internally
2919 ** and must not be freed by the application)^.
2921 ** When the serialized [threading mode] is in use, it might be the
2922 ** case that a second error occurs on a separate thread in between
2923 ** the time of the first error and the call to these interfaces.
2924 ** When that happens, the second error will be reported since these
2925 ** interfaces always report the most recent result. To avoid
2926 ** this, each thread can obtain exclusive use of the [database connection] D
2927 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
2928 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
2929 ** all calls to the interfaces listed here are completed.
2931 ** If an interface fails with SQLITE_MISUSE, that means the interface
2932 ** was invoked incorrectly by the application. In that case, the
2933 ** error code and message may or may not be set.
2935 SQLITE_API
int sqlite3_errcode(sqlite3
*db
);
2936 SQLITE_API
int sqlite3_extended_errcode(sqlite3
*db
);
2937 SQLITE_API
const char *sqlite3_errmsg(sqlite3
*);
2938 SQLITE_API
const void *sqlite3_errmsg16(sqlite3
*);
2939 SQLITE_API
const char *sqlite3_errstr(int);
2942 ** CAPI3REF: SQL Statement Object
2943 ** KEYWORDS: {prepared statement} {prepared statements}
2945 ** An instance of this object represents a single SQL statement.
2946 ** This object is variously known as a "prepared statement" or a
2947 ** "compiled SQL statement" or simply as a "statement".
2949 ** The life of a statement object goes something like this:
2952 ** <li> Create the object using [sqlite3_prepare_v2()] or a related
2954 ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
2956 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
2957 ** <li> Reset the statement using [sqlite3_reset()] then go back
2958 ** to step 2. Do this zero or more times.
2959 ** <li> Destroy the object using [sqlite3_finalize()].
2962 ** Refer to documentation on individual methods above for additional
2965 typedef struct sqlite3_stmt sqlite3_stmt
;
2968 ** CAPI3REF: Run-time Limits
2970 ** ^(This interface allows the size of various constructs to be limited
2971 ** on a connection by connection basis. The first parameter is the
2972 ** [database connection] whose limit is to be set or queried. The
2973 ** second parameter is one of the [limit categories] that define a
2974 ** class of constructs to be size limited. The third parameter is the
2975 ** new limit for that construct.)^
2977 ** ^If the new limit is a negative number, the limit is unchanged.
2978 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
2979 ** [limits | hard upper bound]
2980 ** set at compile-time by a C preprocessor macro called
2981 ** [limits | SQLITE_MAX_<i>NAME</i>].
2982 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
2983 ** ^Attempts to increase a limit above its hard upper bound are
2984 ** silently truncated to the hard upper bound.
2986 ** ^Regardless of whether or not the limit was changed, the
2987 ** [sqlite3_limit()] interface returns the prior value of the limit.
2988 ** ^Hence, to find the current value of a limit without changing it,
2989 ** simply invoke this interface with the third parameter set to -1.
2991 ** Run-time limits are intended for use in applications that manage
2992 ** both their own internal database and also databases that are controlled
2993 ** by untrusted external sources. An example application might be a
2994 ** web browser that has its own databases for storing history and
2995 ** separate databases controlled by JavaScript applications downloaded
2996 ** off the Internet. The internal databases can be given the
2997 ** large, default limits. Databases managed by external sources can
2998 ** be given much smaller limits designed to prevent a denial of service
2999 ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
3000 ** interface to further control untrusted SQL. The size of the database
3001 ** created by an untrusted script can be contained using the
3002 ** [max_page_count] [PRAGMA].
3004 ** New run-time limit categories may be added in future releases.
3006 SQLITE_API
int sqlite3_limit(sqlite3
*, int id
, int newVal
);
3009 ** CAPI3REF: Run-Time Limit Categories
3010 ** KEYWORDS: {limit category} {*limit categories}
3012 ** These constants define various performance limits
3013 ** that can be lowered at run-time using [sqlite3_limit()].
3014 ** The synopsis of the meanings of the various limits is shown below.
3015 ** Additional information is available at [limits | Limits in SQLite].
3018 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3019 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3021 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3022 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3024 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3025 ** <dd>The maximum number of columns in a table definition or in the
3026 ** result set of a [SELECT] or the maximum number of columns in an index
3027 ** or in an ORDER BY or GROUP BY clause.</dd>)^
3029 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3030 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3032 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3033 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3035 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3036 ** <dd>The maximum number of instructions in a virtual machine program
3037 ** used to implement an SQL statement. This limit is not currently
3038 ** enforced, though that might be added in some future release of
3041 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3042 ** <dd>The maximum number of arguments on a function.</dd>)^
3044 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3045 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3047 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3048 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3049 ** <dd>The maximum length of the pattern argument to the [LIKE] or
3050 ** [GLOB] operators.</dd>)^
3052 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3053 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3054 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3056 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3057 ** <dd>The maximum depth of recursion for triggers.</dd>)^
3060 #define SQLITE_LIMIT_LENGTH 0
3061 #define SQLITE_LIMIT_SQL_LENGTH 1
3062 #define SQLITE_LIMIT_COLUMN 2
3063 #define SQLITE_LIMIT_EXPR_DEPTH 3
3064 #define SQLITE_LIMIT_COMPOUND_SELECT 4
3065 #define SQLITE_LIMIT_VDBE_OP 5
3066 #define SQLITE_LIMIT_FUNCTION_ARG 6
3067 #define SQLITE_LIMIT_ATTACHED 7
3068 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
3069 #define SQLITE_LIMIT_VARIABLE_NUMBER 9
3070 #define SQLITE_LIMIT_TRIGGER_DEPTH 10
3073 ** CAPI3REF: Compiling An SQL Statement
3074 ** KEYWORDS: {SQL statement compiler}
3076 ** To execute an SQL query, it must first be compiled into a byte-code
3077 ** program using one of these routines.
3079 ** The first argument, "db", is a [database connection] obtained from a
3080 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3081 ** [sqlite3_open16()]. The database connection must not have been closed.
3083 ** The second argument, "zSql", is the statement to be compiled, encoded
3084 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
3085 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
3088 ** ^If the nByte argument is less than zero, then zSql is read up to the
3089 ** first zero terminator. ^If nByte is non-negative, then it is the maximum
3090 ** number of bytes read from zSql. ^When nByte is non-negative, the
3091 ** zSql string ends at either the first '\000' or '\u0000' character or
3092 ** the nByte-th byte, whichever comes first. If the caller knows
3093 ** that the supplied string is nul-terminated, then there is a small
3094 ** performance advantage to be gained by passing an nByte parameter that
3095 ** is equal to the number of bytes in the input string <i>including</i>
3096 ** the nul-terminator bytes as this saves SQLite from having to
3097 ** make a copy of the input string.
3099 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3100 ** past the end of the first SQL statement in zSql. These routines only
3101 ** compile the first statement in zSql, so *pzTail is left pointing to
3102 ** what remains uncompiled.
3104 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3105 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
3106 ** to NULL. ^If the input text contains no SQL (if the input is an empty
3107 ** string or a comment) then *ppStmt is set to NULL.
3108 ** The calling procedure is responsible for deleting the compiled
3109 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
3110 ** ppStmt may not be NULL.
3112 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3113 ** otherwise an [error code] is returned.
3115 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
3116 ** recommended for all new programs. The two older interfaces are retained
3117 ** for backwards compatibility, but their use is discouraged.
3118 ** ^In the "v2" interfaces, the prepared statement
3119 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
3120 ** original SQL text. This causes the [sqlite3_step()] interface to
3121 ** behave differently in three ways:
3125 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3126 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
3127 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3128 ** retries will occur before sqlite3_step() gives up and returns an error.
3132 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3133 ** [error codes] or [extended error codes]. ^The legacy behavior was that
3134 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3135 ** and the application would have to make a second call to [sqlite3_reset()]
3136 ** in order to find the underlying cause of the problem. With the "v2" prepare
3137 ** interfaces, the underlying reason for the error is returned immediately.
3141 ** ^If the specific value bound to [parameter | host parameter] in the
3142 ** WHERE clause might influence the choice of query plan for a statement,
3143 ** then the statement will be automatically recompiled, as if there had been
3144 ** a schema change, on the first [sqlite3_step()] call following any change
3145 ** to the [sqlite3_bind_text | bindings] of that [parameter].
3146 ** ^The specific value of WHERE-clause [parameter] might influence the
3147 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
3148 ** or [GLOB] operator or if the parameter is compared to an indexed column
3149 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3153 SQLITE_API
int sqlite3_prepare(
3154 sqlite3
*db
, /* Database handle */
3155 const char *zSql
, /* SQL statement, UTF-8 encoded */
3156 int nByte
, /* Maximum length of zSql in bytes. */
3157 sqlite3_stmt
**ppStmt
, /* OUT: Statement handle */
3158 const char **pzTail
/* OUT: Pointer to unused portion of zSql */
3160 SQLITE_API
int sqlite3_prepare_v2(
3161 sqlite3
*db
, /* Database handle */
3162 const char *zSql
, /* SQL statement, UTF-8 encoded */
3163 int nByte
, /* Maximum length of zSql in bytes. */
3164 sqlite3_stmt
**ppStmt
, /* OUT: Statement handle */
3165 const char **pzTail
/* OUT: Pointer to unused portion of zSql */
3167 SQLITE_API
int sqlite3_prepare16(
3168 sqlite3
*db
, /* Database handle */
3169 const void *zSql
, /* SQL statement, UTF-16 encoded */
3170 int nByte
, /* Maximum length of zSql in bytes. */
3171 sqlite3_stmt
**ppStmt
, /* OUT: Statement handle */
3172 const void **pzTail
/* OUT: Pointer to unused portion of zSql */
3174 SQLITE_API
int sqlite3_prepare16_v2(
3175 sqlite3
*db
, /* Database handle */
3176 const void *zSql
, /* SQL statement, UTF-16 encoded */
3177 int nByte
, /* Maximum length of zSql in bytes. */
3178 sqlite3_stmt
**ppStmt
, /* OUT: Statement handle */
3179 const void **pzTail
/* OUT: Pointer to unused portion of zSql */
3183 ** CAPI3REF: Retrieving Statement SQL
3185 ** ^This interface can be used to retrieve a saved copy of the original
3186 ** SQL text used to create a [prepared statement] if that statement was
3187 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
3189 SQLITE_API
const char *sqlite3_sql(sqlite3_stmt
*pStmt
);
3192 ** CAPI3REF: Determine If An SQL Statement Writes The Database
3194 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3195 ** and only if the [prepared statement] X makes no direct changes to
3196 ** the content of the database file.
3198 ** Note that [application-defined SQL functions] or
3199 ** [virtual tables] might change the database indirectly as a side effect.
3200 ** ^(For example, if an application defines a function "eval()" that
3201 ** calls [sqlite3_exec()], then the following SQL statement would
3202 ** change the database file through side-effects:
3204 ** <blockquote><pre>
3205 ** SELECT eval('DELETE FROM t1') FROM t2;
3206 ** </pre></blockquote>
3208 ** But because the [SELECT] statement does not change the database file
3209 ** directly, sqlite3_stmt_readonly() would still return true.)^
3211 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3212 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3213 ** since the statements themselves do not actually modify the database but
3214 ** rather they control the timing of when other statements modify the
3215 ** database. ^The [ATTACH] and [DETACH] statements also cause
3216 ** sqlite3_stmt_readonly() to return true since, while those statements
3217 ** change the configuration of a database connection, they do not make
3218 ** changes to the content of the database files on disk.
3220 SQLITE_API
int sqlite3_stmt_readonly(sqlite3_stmt
*pStmt
);
3223 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3225 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3226 ** [prepared statement] S has been stepped at least once using
3227 ** [sqlite3_step(S)] but has not run to completion and/or has not
3228 ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
3229 ** interface returns false if S is a NULL pointer. If S is not a
3230 ** NULL pointer and is not a pointer to a valid [prepared statement]
3231 ** object, then the behavior is undefined and probably undesirable.
3233 ** This interface can be used in combination [sqlite3_next_stmt()]
3234 ** to locate all prepared statements associated with a database
3235 ** connection that are in need of being reset. This can be used,
3236 ** for example, in diagnostic routines to search for prepared
3237 ** statements that are holding a transaction open.
3239 SQLITE_API
int sqlite3_stmt_busy(sqlite3_stmt
*);
3242 ** CAPI3REF: Dynamically Typed Value Object
3243 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3245 ** SQLite uses the sqlite3_value object to represent all values
3246 ** that can be stored in a database table. SQLite uses dynamic typing
3247 ** for the values it stores. ^Values stored in sqlite3_value objects
3248 ** can be integers, floating point values, strings, BLOBs, or NULL.
3250 ** An sqlite3_value object may be either "protected" or "unprotected".
3251 ** Some interfaces require a protected sqlite3_value. Other interfaces
3252 ** will accept either a protected or an unprotected sqlite3_value.
3253 ** Every interface that accepts sqlite3_value arguments specifies
3254 ** whether or not it requires a protected sqlite3_value.
3256 ** The terms "protected" and "unprotected" refer to whether or not
3257 ** a mutex is held. An internal mutex is held for a protected
3258 ** sqlite3_value object but no mutex is held for an unprotected
3259 ** sqlite3_value object. If SQLite is compiled to be single-threaded
3260 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3261 ** or if SQLite is run in one of reduced mutex modes
3262 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3263 ** then there is no distinction between protected and unprotected
3264 ** sqlite3_value objects and they can be used interchangeably. However,
3265 ** for maximum code portability it is recommended that applications
3266 ** still make the distinction between protected and unprotected
3267 ** sqlite3_value objects even when not strictly required.
3269 ** ^The sqlite3_value objects that are passed as parameters into the
3270 ** implementation of [application-defined SQL functions] are protected.
3271 ** ^The sqlite3_value object returned by
3272 ** [sqlite3_column_value()] is unprotected.
3273 ** Unprotected sqlite3_value objects may only be used with
3274 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
3275 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
3276 ** interfaces require protected sqlite3_value objects.
3278 typedef struct Mem sqlite3_value
;
3281 ** CAPI3REF: SQL Function Context Object
3283 ** The context in which an SQL function executes is stored in an
3284 ** sqlite3_context object. ^A pointer to an sqlite3_context object
3285 ** is always first parameter to [application-defined SQL functions].
3286 ** The application-defined SQL function implementation will pass this
3287 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3288 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3289 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3290 ** and/or [sqlite3_set_auxdata()].
3292 typedef struct sqlite3_context sqlite3_context
;
3295 ** CAPI3REF: Binding Values To Prepared Statements
3296 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3297 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3299 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3300 ** literals may be replaced by a [parameter] that matches one of following
3311 ** In the templates above, NNN represents an integer literal,
3312 ** and VVV represents an alphanumeric identifier.)^ ^The values of these
3313 ** parameters (also called "host parameter names" or "SQL parameters")
3314 ** can be set using the sqlite3_bind_*() routines defined here.
3316 ** ^The first argument to the sqlite3_bind_*() routines is always
3317 ** a pointer to the [sqlite3_stmt] object returned from
3318 ** [sqlite3_prepare_v2()] or its variants.
3320 ** ^The second argument is the index of the SQL parameter to be set.
3321 ** ^The leftmost SQL parameter has an index of 1. ^When the same named
3322 ** SQL parameter is used more than once, second and subsequent
3323 ** occurrences have the same index as the first occurrence.
3324 ** ^The index for named parameters can be looked up using the
3325 ** [sqlite3_bind_parameter_index()] API if desired. ^The index
3326 ** for "?NNN" parameters is the value of NNN.
3327 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
3328 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3330 ** ^The third argument is the value to bind to the parameter.
3331 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3332 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3333 ** is ignored and the end result is the same as sqlite3_bind_null().
3335 ** ^(In those routines that have a fourth argument, its value is the
3336 ** number of bytes in the parameter. To be clear: the value is the
3337 ** number of <u>bytes</u> in the value, not the number of characters.)^
3338 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3339 ** is negative, then the length of the string is
3340 ** the number of bytes up to the first zero terminator.
3341 ** If the fourth parameter to sqlite3_bind_blob() is negative, then
3342 ** the behavior is undefined.
3343 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3344 ** or sqlite3_bind_text16() then that parameter must be the byte offset
3345 ** where the NUL terminator would occur assuming the string were NUL
3346 ** terminated. If any NUL characters occur at byte offsets less than
3347 ** the value of the fourth parameter then the resulting string value will
3348 ** contain embedded NULs. The result of expressions involving strings
3349 ** with embedded NULs is undefined.
3351 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
3352 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
3353 ** string after SQLite has finished with it. ^The destructor is called
3354 ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(),
3355 ** sqlite3_bind_text(), or sqlite3_bind_text16() fails.
3356 ** ^If the fifth argument is
3357 ** the special value [SQLITE_STATIC], then SQLite assumes that the
3358 ** information is in static, unmanaged space and does not need to be freed.
3359 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3360 ** SQLite makes its own private copy of the data immediately, before
3361 ** the sqlite3_bind_*() routine returns.
3363 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3364 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
3365 ** (just an integer to hold its size) while it is being processed.
3366 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
3367 ** content is later written using
3368 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
3369 ** ^A negative value for the zeroblob results in a zero-length BLOB.
3371 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3372 ** for the [prepared statement] or with a prepared statement for which
3373 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3374 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
3375 ** routine is passed a [prepared statement] that has been finalized, the
3376 ** result is undefined and probably harmful.
3378 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3379 ** ^Unbound parameters are interpreted as NULL.
3381 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3382 ** [error code] if anything goes wrong.
3383 ** ^[SQLITE_RANGE] is returned if the parameter
3384 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
3386 ** See also: [sqlite3_bind_parameter_count()],
3387 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3389 SQLITE_API
int sqlite3_bind_blob(sqlite3_stmt
*, int, const void*, int n
, void(*)(void*));
3390 SQLITE_API
int sqlite3_bind_double(sqlite3_stmt
*, int, double);
3391 SQLITE_API
int sqlite3_bind_int(sqlite3_stmt
*, int, int);
3392 SQLITE_API
int sqlite3_bind_int64(sqlite3_stmt
*, int, sqlite3_int64
);
3393 SQLITE_API
int sqlite3_bind_null(sqlite3_stmt
*, int);
3394 SQLITE_API
int sqlite3_bind_text(sqlite3_stmt
*, int, const char*, int n
, void(*)(void*));
3395 SQLITE_API
int sqlite3_bind_text16(sqlite3_stmt
*, int, const void*, int, void(*)(void*));
3396 SQLITE_API
int sqlite3_bind_value(sqlite3_stmt
*, int, const sqlite3_value
*);
3397 SQLITE_API
int sqlite3_bind_zeroblob(sqlite3_stmt
*, int, int n
);
3400 ** CAPI3REF: Number Of SQL Parameters
3402 ** ^This routine can be used to find the number of [SQL parameters]
3403 ** in a [prepared statement]. SQL parameters are tokens of the
3404 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3405 ** placeholders for values that are [sqlite3_bind_blob | bound]
3406 ** to the parameters at a later time.
3408 ** ^(This routine actually returns the index of the largest (rightmost)
3409 ** parameter. For all forms except ?NNN, this will correspond to the
3410 ** number of unique parameters. If parameters of the ?NNN form are used,
3411 ** there may be gaps in the list.)^
3413 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3414 ** [sqlite3_bind_parameter_name()], and
3415 ** [sqlite3_bind_parameter_index()].
3417 SQLITE_API
int sqlite3_bind_parameter_count(sqlite3_stmt
*);
3420 ** CAPI3REF: Name Of A Host Parameter
3422 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
3423 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
3424 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3425 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3427 ** In other words, the initial ":" or "$" or "@" or "?"
3428 ** is included as part of the name.)^
3429 ** ^Parameters of the form "?" without a following integer have no name
3430 ** and are referred to as "nameless" or "anonymous parameters".
3432 ** ^The first host parameter has an index of 1, not 0.
3434 ** ^If the value N is out of range or if the N-th parameter is
3435 ** nameless, then NULL is returned. ^The returned string is
3436 ** always in UTF-8 encoding even if the named parameter was
3437 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
3438 ** [sqlite3_prepare16_v2()].
3440 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3441 ** [sqlite3_bind_parameter_count()], and
3442 ** [sqlite3_bind_parameter_index()].
3444 SQLITE_API
const char *sqlite3_bind_parameter_name(sqlite3_stmt
*, int);
3447 ** CAPI3REF: Index Of A Parameter With A Given Name
3449 ** ^Return the index of an SQL parameter given its name. ^The
3450 ** index value returned is suitable for use as the second
3451 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
3452 ** is returned if no matching parameter is found. ^The parameter
3453 ** name must be given in UTF-8 even if the original statement
3454 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3456 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3457 ** [sqlite3_bind_parameter_count()], and
3458 ** [sqlite3_bind_parameter_index()].
3460 SQLITE_API
int sqlite3_bind_parameter_index(sqlite3_stmt
*, const char *zName
);
3463 ** CAPI3REF: Reset All Bindings On A Prepared Statement
3465 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3466 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3467 ** ^Use this routine to reset all host parameters to NULL.
3469 SQLITE_API
int sqlite3_clear_bindings(sqlite3_stmt
*);
3472 ** CAPI3REF: Number Of Columns In A Result Set
3474 ** ^Return the number of columns in the result set returned by the
3475 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3476 ** statement that does not return data (for example an [UPDATE]).
3478 ** See also: [sqlite3_data_count()]
3480 SQLITE_API
int sqlite3_column_count(sqlite3_stmt
*pStmt
);
3483 ** CAPI3REF: Column Names In A Result Set
3485 ** ^These routines return the name assigned to a particular column
3486 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
3487 ** interface returns a pointer to a zero-terminated UTF-8 string
3488 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
3489 ** UTF-16 string. ^The first parameter is the [prepared statement]
3490 ** that implements the [SELECT] statement. ^The second parameter is the
3491 ** column number. ^The leftmost column is number 0.
3493 ** ^The returned string pointer is valid until either the [prepared statement]
3494 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3495 ** reprepared by the first call to [sqlite3_step()] for a particular run
3496 ** or until the next call to
3497 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3499 ** ^If sqlite3_malloc() fails during the processing of either routine
3500 ** (for example during a conversion from UTF-8 to UTF-16) then a
3501 ** NULL pointer is returned.
3503 ** ^The name of a result column is the value of the "AS" clause for
3504 ** that column, if there is an AS clause. If there is no AS clause
3505 ** then the name of the column is unspecified and may change from
3506 ** one release of SQLite to the next.
3508 SQLITE_API
const char *sqlite3_column_name(sqlite3_stmt
*, int N
);
3509 SQLITE_API
const void *sqlite3_column_name16(sqlite3_stmt
*, int N
);
3512 ** CAPI3REF: Source Of Data In A Query Result
3514 ** ^These routines provide a means to determine the database, table, and
3515 ** table column that is the origin of a particular result column in
3516 ** [SELECT] statement.
3517 ** ^The name of the database or table or column can be returned as
3518 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
3519 ** the database name, the _table_ routines return the table name, and
3520 ** the origin_ routines return the column name.
3521 ** ^The returned string is valid until the [prepared statement] is destroyed
3522 ** using [sqlite3_finalize()] or until the statement is automatically
3523 ** reprepared by the first call to [sqlite3_step()] for a particular run
3524 ** or until the same information is requested
3525 ** again in a different encoding.
3527 ** ^The names returned are the original un-aliased names of the
3528 ** database, table, and column.
3530 ** ^The first argument to these interfaces is a [prepared statement].
3531 ** ^These functions return information about the Nth result column returned by
3532 ** the statement, where N is the second function argument.
3533 ** ^The left-most column is column 0 for these routines.
3535 ** ^If the Nth column returned by the statement is an expression or
3536 ** subquery and is not a column value, then all of these functions return
3537 ** NULL. ^These routine might also return NULL if a memory allocation error
3538 ** occurs. ^Otherwise, they return the name of the attached database, table,
3539 ** or column that query result column was extracted from.
3541 ** ^As with all other SQLite APIs, those whose names end with "16" return
3542 ** UTF-16 encoded strings and the other functions return UTF-8.
3544 ** ^These APIs are only available if the library was compiled with the
3545 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3547 ** If two or more threads call one or more of these routines against the same
3548 ** prepared statement and column at the same time then the results are
3551 ** If two or more threads call one or more
3552 ** [sqlite3_column_database_name | column metadata interfaces]
3553 ** for the same [prepared statement] and result column
3554 ** at the same time then the results are undefined.
3556 SQLITE_API
const char *sqlite3_column_database_name(sqlite3_stmt
*,int);
3557 SQLITE_API
const void *sqlite3_column_database_name16(sqlite3_stmt
*,int);
3558 SQLITE_API
const char *sqlite3_column_table_name(sqlite3_stmt
*,int);
3559 SQLITE_API
const void *sqlite3_column_table_name16(sqlite3_stmt
*,int);
3560 SQLITE_API
const char *sqlite3_column_origin_name(sqlite3_stmt
*,int);
3561 SQLITE_API
const void *sqlite3_column_origin_name16(sqlite3_stmt
*,int);
3564 ** CAPI3REF: Declared Datatype Of A Query Result
3566 ** ^(The first parameter is a [prepared statement].
3567 ** If this statement is a [SELECT] statement and the Nth column of the
3568 ** returned result set of that [SELECT] is a table column (not an
3569 ** expression or subquery) then the declared type of the table
3570 ** column is returned.)^ ^If the Nth column of the result set is an
3571 ** expression or subquery, then a NULL pointer is returned.
3572 ** ^The returned string is always UTF-8 encoded.
3574 ** ^(For example, given the database schema:
3576 ** CREATE TABLE t1(c1 VARIANT);
3578 ** and the following statement to be compiled:
3580 ** SELECT c1 + 1, c1 FROM t1;
3582 ** this routine would return the string "VARIANT" for the second result
3583 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
3585 ** ^SQLite uses dynamic run-time typing. ^So just because a column
3586 ** is declared to contain a particular type does not mean that the
3587 ** data stored in that column is of the declared type. SQLite is
3588 ** strongly typed, but the typing is dynamic not static. ^Type
3589 ** is associated with individual values, not with the containers
3590 ** used to hold those values.
3592 SQLITE_API
const char *sqlite3_column_decltype(sqlite3_stmt
*,int);
3593 SQLITE_API
const void *sqlite3_column_decltype16(sqlite3_stmt
*,int);
3596 ** CAPI3REF: Evaluate An SQL Statement
3598 ** After a [prepared statement] has been prepared using either
3599 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3600 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3601 ** must be called one or more times to evaluate the statement.
3603 ** The details of the behavior of the sqlite3_step() interface depend
3604 ** on whether the statement was prepared using the newer "v2" interface
3605 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3606 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
3607 ** new "v2" interface is recommended for new applications but the legacy
3608 ** interface will continue to be supported.
3610 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3611 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3612 ** ^With the "v2" interface, any of the other [result codes] or
3613 ** [extended result codes] might be returned as well.
3615 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3616 ** database locks it needs to do its job. ^If the statement is a [COMMIT]
3617 ** or occurs outside of an explicit transaction, then you can retry the
3618 ** statement. If the statement is not a [COMMIT] and occurs within an
3619 ** explicit transaction then you should rollback the transaction before
3622 ** ^[SQLITE_DONE] means that the statement has finished executing
3623 ** successfully. sqlite3_step() should not be called again on this virtual
3624 ** machine without first calling [sqlite3_reset()] to reset the virtual
3625 ** machine back to its initial state.
3627 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3628 ** is returned each time a new row of data is ready for processing by the
3629 ** caller. The values may be accessed using the [column access functions].
3630 ** sqlite3_step() is called again to retrieve the next row of data.
3632 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3633 ** violation) has occurred. sqlite3_step() should not be called again on
3634 ** the VM. More information may be found by calling [sqlite3_errmsg()].
3635 ** ^With the legacy interface, a more specific error code (for example,
3636 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3637 ** can be obtained by calling [sqlite3_reset()] on the
3638 ** [prepared statement]. ^In the "v2" interface,
3639 ** the more specific error code is returned directly by sqlite3_step().
3641 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3642 ** Perhaps it was called on a [prepared statement] that has
3643 ** already been [sqlite3_finalize | finalized] or on one that had
3644 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
3645 ** be the case that the same database connection is being used by two or
3646 ** more threads at the same moment in time.
3648 ** For all versions of SQLite up to and including 3.6.23.1, a call to
3649 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
3650 ** other than [SQLITE_ROW] before any subsequent invocation of
3651 ** sqlite3_step(). Failure to reset the prepared statement using
3652 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3653 ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began
3654 ** calling [sqlite3_reset()] automatically in this circumstance rather
3655 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
3656 ** break because any application that ever receives an SQLITE_MISUSE error
3657 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
3658 ** can be used to restore the legacy behavior.
3660 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3661 ** API always returns a generic error code, [SQLITE_ERROR], following any
3662 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
3663 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3664 ** specific [error codes] that better describes the error.
3665 ** We admit that this is a goofy design. The problem has been fixed
3666 ** with the "v2" interface. If you prepare all of your SQL statements
3667 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3668 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3669 ** then the more specific [error codes] are returned directly
3670 ** by sqlite3_step(). The use of the "v2" interface is recommended.
3672 SQLITE_API
int sqlite3_step(sqlite3_stmt
*);
3675 ** CAPI3REF: Number of columns in a result set
3677 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
3678 ** current row of the result set of [prepared statement] P.
3679 ** ^If prepared statement P does not have results ready to return
3680 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3681 ** interfaces) then sqlite3_data_count(P) returns 0.
3682 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3683 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
3684 ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
3685 ** will return non-zero if previous call to [sqlite3_step](P) returned
3686 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
3687 ** where it always returns zero since each step of that multi-step
3688 ** pragma returns 0 columns of data.
3690 ** See also: [sqlite3_column_count()]
3692 SQLITE_API
int sqlite3_data_count(sqlite3_stmt
*pStmt
);
3695 ** CAPI3REF: Fundamental Datatypes
3696 ** KEYWORDS: SQLITE_TEXT
3698 ** ^(Every value in SQLite has one of five fundamental datatypes:
3701 ** <li> 64-bit signed integer
3702 ** <li> 64-bit IEEE floating point number
3708 ** These constants are codes for each of those types.
3710 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3711 ** for a completely different meaning. Software that links against both
3712 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3715 #define SQLITE_INTEGER 1
3716 #define SQLITE_FLOAT 2
3717 #define SQLITE_BLOB 4
3718 #define SQLITE_NULL 5
3722 # define SQLITE_TEXT 3
3724 #define SQLITE3_TEXT 3
3727 ** CAPI3REF: Result Values From A Query
3728 ** KEYWORDS: {column access functions}
3730 ** These routines form the "result set" interface.
3732 ** ^These routines return information about a single column of the current
3733 ** result row of a query. ^In every case the first argument is a pointer
3734 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3735 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3736 ** and the second argument is the index of the column for which information
3737 ** should be returned. ^The leftmost column of the result set has the index 0.
3738 ** ^The number of columns in the result can be determined using
3739 ** [sqlite3_column_count()].
3741 ** If the SQL statement does not currently point to a valid row, or if the
3742 ** column index is out of range, the result is undefined.
3743 ** These routines may only be called when the most recent call to
3744 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3745 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3746 ** If any of these routines are called after [sqlite3_reset()] or
3747 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3748 ** something other than [SQLITE_ROW], the results are undefined.
3749 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3750 ** are called from a different thread while any of these routines
3751 ** are pending, then the results are undefined.
3753 ** ^The sqlite3_column_type() routine returns the
3754 ** [SQLITE_INTEGER | datatype code] for the initial data type
3755 ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
3756 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
3757 ** returned by sqlite3_column_type() is only meaningful if no type
3758 ** conversions have occurred as described below. After a type conversion,
3759 ** the value returned by sqlite3_column_type() is undefined. Future
3760 ** versions of SQLite may change the behavior of sqlite3_column_type()
3761 ** following a type conversion.
3763 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3764 ** routine returns the number of bytes in that BLOB or string.
3765 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3766 ** the string to UTF-8 and then returns the number of bytes.
3767 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
3768 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3769 ** the number of bytes in that string.
3770 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3772 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3773 ** routine returns the number of bytes in that BLOB or string.
3774 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3775 ** the string to UTF-16 and then returns the number of bytes.
3776 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3777 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3778 ** the number of bytes in that string.
3779 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3781 ** ^The values returned by [sqlite3_column_bytes()] and
3782 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3783 ** of the string. ^For clarity: the values returned by
3784 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3785 ** bytes in the string, not the number of characters.
3787 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3788 ** even empty strings, are always zero-terminated. ^The return
3789 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3791 ** ^The object returned by [sqlite3_column_value()] is an
3792 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object
3793 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
3794 ** If the [unprotected sqlite3_value] object returned by
3795 ** [sqlite3_column_value()] is used in any other way, including calls
3796 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3797 ** or [sqlite3_value_bytes()], then the behavior is undefined.
3799 ** These routines attempt to convert the value where appropriate. ^For
3800 ** example, if the internal representation is FLOAT and a text result
3801 ** is requested, [sqlite3_snprintf()] is used internally to perform the
3802 ** conversion automatically. ^(The following table details the conversions
3803 ** that are applied:
3806 ** <table border="1">
3807 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
3809 ** <tr><td> NULL <td> INTEGER <td> Result is 0
3810 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
3811 ** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer
3812 ** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer
3813 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
3814 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
3815 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
3816 ** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER
3817 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
3818 ** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB
3819 ** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER
3820 ** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL
3821 ** <tr><td> TEXT <td> BLOB <td> No change
3822 ** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER
3823 ** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL
3824 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
3828 ** The table above makes reference to standard C library functions atoi()
3829 ** and atof(). SQLite does not really use these functions. It has its
3830 ** own equivalent internal routines. The atoi() and atof() names are
3831 ** used in the table for brevity and because they are familiar to most
3834 ** Note that when type conversions occur, pointers returned by prior
3835 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
3836 ** sqlite3_column_text16() may be invalidated.
3837 ** Type conversions and pointer invalidations might occur
3838 ** in the following cases:
3841 ** <li> The initial content is a BLOB and sqlite3_column_text() or
3842 ** sqlite3_column_text16() is called. A zero-terminator might
3843 ** need to be added to the string.</li>
3844 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
3845 ** sqlite3_column_text16() is called. The content must be converted
3847 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
3848 ** sqlite3_column_text() is called. The content must be converted
3852 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
3853 ** not invalidate a prior pointer, though of course the content of the buffer
3854 ** that the prior pointer references will have been modified. Other kinds
3855 ** of conversion are done in place when it is possible, but sometimes they
3856 ** are not possible and in those cases prior pointers are invalidated.
3858 ** The safest and easiest to remember policy is to invoke these routines
3859 ** in one of the following ways:
3862 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
3863 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
3864 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
3867 ** In other words, you should call sqlite3_column_text(),
3868 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
3869 ** into the desired format, then invoke sqlite3_column_bytes() or
3870 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
3871 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
3872 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
3873 ** with calls to sqlite3_column_bytes().
3875 ** ^The pointers returned are valid until a type conversion occurs as
3876 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
3877 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
3878 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned
3879 ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
3880 ** [sqlite3_free()].
3882 ** ^(If a memory allocation error occurs during the evaluation of any
3883 ** of these routines, a default value is returned. The default value
3884 ** is either the integer 0, the floating point number 0.0, or a NULL
3885 ** pointer. Subsequent calls to [sqlite3_errcode()] will return
3886 ** [SQLITE_NOMEM].)^
3888 SQLITE_API
const void *sqlite3_column_blob(sqlite3_stmt
*, int iCol
);
3889 SQLITE_API
int sqlite3_column_bytes(sqlite3_stmt
*, int iCol
);
3890 SQLITE_API
int sqlite3_column_bytes16(sqlite3_stmt
*, int iCol
);
3891 SQLITE_API
double sqlite3_column_double(sqlite3_stmt
*, int iCol
);
3892 SQLITE_API
int sqlite3_column_int(sqlite3_stmt
*, int iCol
);
3893 SQLITE_API sqlite3_int64
sqlite3_column_int64(sqlite3_stmt
*, int iCol
);
3894 SQLITE_API
const unsigned char *sqlite3_column_text(sqlite3_stmt
*, int iCol
);
3895 SQLITE_API
const void *sqlite3_column_text16(sqlite3_stmt
*, int iCol
);
3896 SQLITE_API
int sqlite3_column_type(sqlite3_stmt
*, int iCol
);
3897 SQLITE_API sqlite3_value
*sqlite3_column_value(sqlite3_stmt
*, int iCol
);
3900 ** CAPI3REF: Destroy A Prepared Statement Object
3902 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
3903 ** ^If the most recent evaluation of the statement encountered no errors
3904 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
3905 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
3906 ** sqlite3_finalize(S) returns the appropriate [error code] or
3907 ** [extended error code].
3909 ** ^The sqlite3_finalize(S) routine can be called at any point during
3910 ** the life cycle of [prepared statement] S:
3911 ** before statement S is ever evaluated, after
3912 ** one or more calls to [sqlite3_reset()], or after any call
3913 ** to [sqlite3_step()] regardless of whether or not the statement has
3914 ** completed execution.
3916 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
3918 ** The application must finalize every [prepared statement] in order to avoid
3919 ** resource leaks. It is a grievous error for the application to try to use
3920 ** a prepared statement after it has been finalized. Any use of a prepared
3921 ** statement after it has been finalized can result in undefined and
3922 ** undesirable behavior such as segfaults and heap corruption.
3924 SQLITE_API
int sqlite3_finalize(sqlite3_stmt
*pStmt
);
3927 ** CAPI3REF: Reset A Prepared Statement Object
3929 ** The sqlite3_reset() function is called to reset a [prepared statement]
3930 ** object back to its initial state, ready to be re-executed.
3931 ** ^Any SQL statement variables that had values bound to them using
3932 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
3933 ** Use [sqlite3_clear_bindings()] to reset the bindings.
3935 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
3936 ** back to the beginning of its program.
3938 ** ^If the most recent call to [sqlite3_step(S)] for the
3939 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
3940 ** or if [sqlite3_step(S)] has never before been called on S,
3941 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
3943 ** ^If the most recent call to [sqlite3_step(S)] for the
3944 ** [prepared statement] S indicated an error, then
3945 ** [sqlite3_reset(S)] returns an appropriate [error code].
3947 ** ^The [sqlite3_reset(S)] interface does not change the values
3948 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
3950 SQLITE_API
int sqlite3_reset(sqlite3_stmt
*pStmt
);
3953 ** CAPI3REF: Create Or Redefine SQL Functions
3954 ** KEYWORDS: {function creation routines}
3955 ** KEYWORDS: {application-defined SQL function}
3956 ** KEYWORDS: {application-defined SQL functions}
3958 ** ^These functions (collectively known as "function creation routines")
3959 ** are used to add SQL functions or aggregates or to redefine the behavior
3960 ** of existing SQL functions or aggregates. The only differences between
3961 ** these routines are the text encoding expected for
3962 ** the second parameter (the name of the function being created)
3963 ** and the presence or absence of a destructor callback for
3964 ** the application data pointer.
3966 ** ^The first parameter is the [database connection] to which the SQL
3967 ** function is to be added. ^If an application uses more than one database
3968 ** connection then application-defined SQL functions must be added
3969 ** to each database connection separately.
3971 ** ^The second parameter is the name of the SQL function to be created or
3972 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
3973 ** representation, exclusive of the zero-terminator. ^Note that the name
3974 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
3975 ** ^Any attempt to create a function with a longer name
3976 ** will result in [SQLITE_MISUSE] being returned.
3978 ** ^The third parameter (nArg)
3979 ** is the number of arguments that the SQL function or
3980 ** aggregate takes. ^If this parameter is -1, then the SQL function or
3981 ** aggregate may take any number of arguments between 0 and the limit
3982 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
3983 ** parameter is less than -1 or greater than 127 then the behavior is
3986 ** ^The fourth parameter, eTextRep, specifies what
3987 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
3988 ** its parameters. The application should set this parameter to
3989 ** [SQLITE_UTF16LE] if the function implementation invokes
3990 ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
3991 ** implementation invokes [sqlite3_value_text16be()] on an input, or
3992 ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
3993 ** otherwise. ^The same SQL function may be registered multiple times using
3994 ** different preferred text encodings, with different implementations for
3996 ** ^When multiple implementations of the same function are available, SQLite
3997 ** will pick the one that involves the least amount of data conversion.
3999 ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4000 ** to signal that the function will always return the same result given
4001 ** the same inputs within a single SQL statement. Most SQL functions are
4002 ** deterministic. The built-in [random()] SQL function is an example of a
4003 ** function that is not deterministic. The SQLite query planner is able to
4004 ** perform additional optimizations on deterministic functions, so use
4005 ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4007 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
4008 ** function can gain access to this pointer using [sqlite3_user_data()].)^
4010 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
4011 ** pointers to C-language functions that implement the SQL function or
4012 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4013 ** callback only; NULL pointers must be passed as the xStep and xFinal
4014 ** parameters. ^An aggregate SQL function requires an implementation of xStep
4015 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4016 ** SQL function or aggregate, pass NULL pointers for all three function
4019 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
4020 ** then it is destructor for the application data pointer.
4021 ** The destructor is invoked when the function is deleted, either by being
4022 ** overloaded or when the database connection closes.)^
4023 ** ^The destructor is also invoked if the call to
4024 ** sqlite3_create_function_v2() fails.
4025 ** ^When the destructor callback of the tenth parameter is invoked, it
4026 ** is passed a single argument which is a copy of the application data
4027 ** pointer which was the fifth parameter to sqlite3_create_function_v2().
4029 ** ^It is permitted to register multiple implementations of the same
4030 ** functions with the same name but with either differing numbers of
4031 ** arguments or differing preferred text encodings. ^SQLite will use
4032 ** the implementation that most closely matches the way in which the
4033 ** SQL function is used. ^A function implementation with a non-negative
4034 ** nArg parameter is a better match than a function implementation with
4035 ** a negative nArg. ^A function where the preferred text encoding
4036 ** matches the database encoding is a better
4037 ** match than a function where the encoding is different.
4038 ** ^A function where the encoding difference is between UTF16le and UTF16be
4039 ** is a closer match than a function where the encoding difference is
4040 ** between UTF8 and UTF16.
4042 ** ^Built-in functions may be overloaded by new application-defined functions.
4044 ** ^An application-defined function is permitted to call other
4045 ** SQLite interfaces. However, such calls must not
4046 ** close the database connection nor finalize or reset the prepared
4047 ** statement in which the function is running.
4049 SQLITE_API
int sqlite3_create_function(
4051 const char *zFunctionName
,
4055 void (*xFunc
)(sqlite3_context
*,int,sqlite3_value
**),
4056 void (*xStep
)(sqlite3_context
*,int,sqlite3_value
**),
4057 void (*xFinal
)(sqlite3_context
*)
4059 SQLITE_API
int sqlite3_create_function16(
4061 const void *zFunctionName
,
4065 void (*xFunc
)(sqlite3_context
*,int,sqlite3_value
**),
4066 void (*xStep
)(sqlite3_context
*,int,sqlite3_value
**),
4067 void (*xFinal
)(sqlite3_context
*)
4069 SQLITE_API
int sqlite3_create_function_v2(
4071 const char *zFunctionName
,
4075 void (*xFunc
)(sqlite3_context
*,int,sqlite3_value
**),
4076 void (*xStep
)(sqlite3_context
*,int,sqlite3_value
**),
4077 void (*xFinal
)(sqlite3_context
*),
4078 void(*xDestroy
)(void*)
4082 ** CAPI3REF: Text Encodings
4084 ** These constant define integer codes that represent the various
4085 ** text encodings supported by SQLite.
4087 #define SQLITE_UTF8 1
4088 #define SQLITE_UTF16LE 2
4089 #define SQLITE_UTF16BE 3
4090 #define SQLITE_UTF16 4 /* Use native byte order */
4091 #define SQLITE_ANY 5 /* Deprecated */
4092 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
4095 ** CAPI3REF: Function Flags
4097 ** These constants may be ORed together with the
4098 ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4099 ** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4100 ** [sqlite3_create_function_v2()].
4102 #define SQLITE_DETERMINISTIC 0x800
4105 ** CAPI3REF: Deprecated Functions
4108 ** These functions are [deprecated]. In order to maintain
4109 ** backwards compatibility with older code, these functions continue
4110 ** to be supported. However, new applications should avoid
4111 ** the use of these functions. To help encourage people to avoid
4112 ** using these functions, we are not going to tell you what they do.
4114 #ifndef SQLITE_OMIT_DEPRECATED
4115 SQLITE_API SQLITE_DEPRECATED
int sqlite3_aggregate_count(sqlite3_context
*);
4116 SQLITE_API SQLITE_DEPRECATED
int sqlite3_expired(sqlite3_stmt
*);
4117 SQLITE_API SQLITE_DEPRECATED
int sqlite3_transfer_bindings(sqlite3_stmt
*, sqlite3_stmt
*);
4118 SQLITE_API SQLITE_DEPRECATED
int sqlite3_global_recover(void);
4119 SQLITE_API SQLITE_DEPRECATED
void sqlite3_thread_cleanup(void);
4120 SQLITE_API SQLITE_DEPRECATED
int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64
,int),
4121 void*,sqlite3_int64
);
4125 ** CAPI3REF: Obtaining SQL Function Parameter Values
4127 ** The C-language implementation of SQL functions and aggregates uses
4128 ** this set of interface routines to access the parameter values on
4129 ** the function or aggregate.
4131 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
4132 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
4133 ** define callbacks that implement the SQL functions and aggregates.
4134 ** The 3rd parameter to these callbacks is an array of pointers to
4135 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
4136 ** each parameter to the SQL function. These routines are used to
4137 ** extract values from the [sqlite3_value] objects.
4139 ** These routines work only with [protected sqlite3_value] objects.
4140 ** Any attempt to use these routines on an [unprotected sqlite3_value]
4141 ** object results in undefined behavior.
4143 ** ^These routines work just like the corresponding [column access functions]
4144 ** except that these routines take a single [protected sqlite3_value] object
4145 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4147 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4148 ** in the native byte-order of the host machine. ^The
4149 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4150 ** extract UTF-16 strings as big-endian and little-endian respectively.
4152 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
4153 ** numeric affinity to the value. This means that an attempt is
4154 ** made to convert the value to an integer or floating point. If
4155 ** such a conversion is possible without loss of information (in other
4156 ** words, if the value is a string that looks like a number)
4157 ** then the conversion is performed. Otherwise no conversion occurs.
4158 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4160 ** Please pay particular attention to the fact that the pointer returned
4161 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4162 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4163 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4164 ** or [sqlite3_value_text16()].
4166 ** These routines must be called from the same thread as
4167 ** the SQL function that supplied the [sqlite3_value*] parameters.
4169 SQLITE_API
const void *sqlite3_value_blob(sqlite3_value
*);
4170 SQLITE_API
int sqlite3_value_bytes(sqlite3_value
*);
4171 SQLITE_API
int sqlite3_value_bytes16(sqlite3_value
*);
4172 SQLITE_API
double sqlite3_value_double(sqlite3_value
*);
4173 SQLITE_API
int sqlite3_value_int(sqlite3_value
*);
4174 SQLITE_API sqlite3_int64
sqlite3_value_int64(sqlite3_value
*);
4175 SQLITE_API
const unsigned char *sqlite3_value_text(sqlite3_value
*);
4176 SQLITE_API
const void *sqlite3_value_text16(sqlite3_value
*);
4177 SQLITE_API
const void *sqlite3_value_text16le(sqlite3_value
*);
4178 SQLITE_API
const void *sqlite3_value_text16be(sqlite3_value
*);
4179 SQLITE_API
int sqlite3_value_type(sqlite3_value
*);
4180 SQLITE_API
int sqlite3_value_numeric_type(sqlite3_value
*);
4183 ** CAPI3REF: Obtain Aggregate Function Context
4185 ** Implementations of aggregate SQL functions use this
4186 ** routine to allocate memory for storing their state.
4188 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4189 ** for a particular aggregate function, SQLite
4190 ** allocates N of memory, zeroes out that memory, and returns a pointer
4191 ** to the new memory. ^On second and subsequent calls to
4192 ** sqlite3_aggregate_context() for the same aggregate function instance,
4193 ** the same buffer is returned. Sqlite3_aggregate_context() is normally
4194 ** called once for each invocation of the xStep callback and then one
4195 ** last time when the xFinal callback is invoked. ^(When no rows match
4196 ** an aggregate query, the xStep() callback of the aggregate function
4197 ** implementation is never called and xFinal() is called exactly once.
4198 ** In those cases, sqlite3_aggregate_context() might be called for the
4199 ** first time from within xFinal().)^
4201 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
4202 ** when first called if N is less than or equal to zero or if a memory
4203 ** allocate error occurs.
4205 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4206 ** determined by the N parameter on first successful call. Changing the
4207 ** value of N in subsequent call to sqlite3_aggregate_context() within
4208 ** the same aggregate function instance will not resize the memory
4209 ** allocation.)^ Within the xFinal callback, it is customary to set
4210 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
4211 ** pointless memory allocations occur.
4213 ** ^SQLite automatically frees the memory allocated by
4214 ** sqlite3_aggregate_context() when the aggregate query concludes.
4216 ** The first parameter must be a copy of the
4217 ** [sqlite3_context | SQL function context] that is the first parameter
4218 ** to the xStep or xFinal callback routine that implements the aggregate
4221 ** This routine must be called from the same thread in which
4222 ** the aggregate SQL function is running.
4224 SQLITE_API
void *sqlite3_aggregate_context(sqlite3_context
*, int nBytes
);
4227 ** CAPI3REF: User Data For Functions
4229 ** ^The sqlite3_user_data() interface returns a copy of
4230 ** the pointer that was the pUserData parameter (the 5th parameter)
4231 ** of the [sqlite3_create_function()]
4232 ** and [sqlite3_create_function16()] routines that originally
4233 ** registered the application defined function.
4235 ** This routine must be called from the same thread in which
4236 ** the application-defined function is running.
4238 SQLITE_API
void *sqlite3_user_data(sqlite3_context
*);
4241 ** CAPI3REF: Database Connection For Functions
4243 ** ^The sqlite3_context_db_handle() interface returns a copy of
4244 ** the pointer to the [database connection] (the 1st parameter)
4245 ** of the [sqlite3_create_function()]
4246 ** and [sqlite3_create_function16()] routines that originally
4247 ** registered the application defined function.
4249 SQLITE_API sqlite3
*sqlite3_context_db_handle(sqlite3_context
*);
4252 ** CAPI3REF: Function Auxiliary Data
4254 ** These functions may be used by (non-aggregate) SQL functions to
4255 ** associate metadata with argument values. If the same value is passed to
4256 ** multiple invocations of the same SQL function during query execution, under
4257 ** some circumstances the associated metadata may be preserved. An example
4258 ** of where this might be useful is in a regular-expression matching
4259 ** function. The compiled version of the regular expression can be stored as
4260 ** metadata associated with the pattern string.
4261 ** Then as long as the pattern string remains the same,
4262 ** the compiled regular expression can be reused on multiple
4263 ** invocations of the same function.
4265 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
4266 ** associated by the sqlite3_set_auxdata() function with the Nth argument
4267 ** value to the application-defined function. ^If there is no metadata
4268 ** associated with the function argument, this sqlite3_get_auxdata() interface
4269 ** returns a NULL pointer.
4271 ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
4272 ** argument of the application-defined function. ^Subsequent
4273 ** calls to sqlite3_get_auxdata(C,N) return P from the most recent
4274 ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
4275 ** NULL if the metadata has been discarded.
4276 ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
4277 ** SQLite will invoke the destructor function X with parameter P exactly
4278 ** once, when the metadata is discarded.
4279 ** SQLite is free to discard the metadata at any time, including: <ul>
4280 ** <li> when the corresponding function parameter changes, or
4281 ** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
4282 ** SQL statement, or
4283 ** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or
4284 ** <li> during the original sqlite3_set_auxdata() call when a memory
4285 ** allocation error occurs. </ul>)^
4287 ** Note the last bullet in particular. The destructor X in
4288 ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
4289 ** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
4290 ** should be called near the end of the function implementation and the
4291 ** function implementation should not make any use of P after
4292 ** sqlite3_set_auxdata() has been called.
4294 ** ^(In practice, metadata is preserved between function calls for
4295 ** function parameters that are compile-time constants, including literal
4296 ** values and [parameters] and expressions composed from the same.)^
4298 ** These routines must be called from the same thread in which
4299 ** the SQL function is running.
4301 SQLITE_API
void *sqlite3_get_auxdata(sqlite3_context
*, int N
);
4302 SQLITE_API
void sqlite3_set_auxdata(sqlite3_context
*, int N
, void*, void (*)(void*));
4306 ** CAPI3REF: Constants Defining Special Destructor Behavior
4308 ** These are special values for the destructor that is passed in as the
4309 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
4310 ** argument is SQLITE_STATIC, it means that the content pointer is constant
4311 ** and will never change. It does not need to be destroyed. ^The
4312 ** SQLITE_TRANSIENT value means that the content will likely change in
4313 ** the near future and that SQLite should make its own private copy of
4314 ** the content before returning.
4316 ** The typedef is necessary to work around problems in certain
4319 typedef void (*sqlite3_destructor_type
)(void*);
4320 #define SQLITE_STATIC ((sqlite3_destructor_type)0)
4321 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
4324 ** CAPI3REF: Setting The Result Of An SQL Function
4326 ** These routines are used by the xFunc or xFinal callbacks that
4327 ** implement SQL functions and aggregates. See
4328 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
4329 ** for additional information.
4331 ** These functions work very much like the [parameter binding] family of
4332 ** functions used to bind values to host parameters in prepared statements.
4333 ** Refer to the [SQL parameter] documentation for additional information.
4335 ** ^The sqlite3_result_blob() interface sets the result from
4336 ** an application-defined function to be the BLOB whose content is pointed
4337 ** to by the second parameter and which is N bytes long where N is the
4340 ** ^The sqlite3_result_zeroblob() interfaces set the result of
4341 ** the application-defined function to be a BLOB containing all zero
4342 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
4344 ** ^The sqlite3_result_double() interface sets the result from
4345 ** an application-defined function to be a floating point value specified
4346 ** by its 2nd argument.
4348 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
4349 ** cause the implemented SQL function to throw an exception.
4350 ** ^SQLite uses the string pointed to by the
4351 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
4352 ** as the text of an error message. ^SQLite interprets the error
4353 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
4354 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
4355 ** byte order. ^If the third parameter to sqlite3_result_error()
4356 ** or sqlite3_result_error16() is negative then SQLite takes as the error
4357 ** message all text up through the first zero character.
4358 ** ^If the third parameter to sqlite3_result_error() or
4359 ** sqlite3_result_error16() is non-negative then SQLite takes that many
4360 ** bytes (not characters) from the 2nd parameter as the error message.
4361 ** ^The sqlite3_result_error() and sqlite3_result_error16()
4362 ** routines make a private copy of the error message text before
4363 ** they return. Hence, the calling function can deallocate or
4364 ** modify the text after they return without harm.
4365 ** ^The sqlite3_result_error_code() function changes the error code
4366 ** returned by SQLite as a result of an error in a function. ^By default,
4367 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
4368 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
4370 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
4371 ** error indicating that a string or BLOB is too long to represent.
4373 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
4374 ** error indicating that a memory allocation failed.
4376 ** ^The sqlite3_result_int() interface sets the return value
4377 ** of the application-defined function to be the 32-bit signed integer
4378 ** value given in the 2nd argument.
4379 ** ^The sqlite3_result_int64() interface sets the return value
4380 ** of the application-defined function to be the 64-bit signed integer
4381 ** value given in the 2nd argument.
4383 ** ^The sqlite3_result_null() interface sets the return value
4384 ** of the application-defined function to be NULL.
4386 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
4387 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
4388 ** set the return value of the application-defined function to be
4389 ** a text string which is represented as UTF-8, UTF-16 native byte order,
4390 ** UTF-16 little endian, or UTF-16 big endian, respectively.
4391 ** ^SQLite takes the text result from the application from
4392 ** the 2nd parameter of the sqlite3_result_text* interfaces.
4393 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4394 ** is negative, then SQLite takes result text from the 2nd parameter
4395 ** through the first zero character.
4396 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4397 ** is non-negative, then as many bytes (not characters) of the text
4398 ** pointed to by the 2nd parameter are taken as the application-defined
4399 ** function result. If the 3rd parameter is non-negative, then it
4400 ** must be the byte offset into the string where the NUL terminator would
4401 ** appear if the string where NUL terminated. If any NUL characters occur
4402 ** in the string at a byte offset that is less than the value of the 3rd
4403 ** parameter, then the resulting string will contain embedded NULs and the
4404 ** result of expressions operating on strings with embedded NULs is undefined.
4405 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4406 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4407 ** function as the destructor on the text or BLOB result when it has
4408 ** finished using that result.
4409 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4410 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4411 ** assumes that the text or BLOB result is in constant space and does not
4412 ** copy the content of the parameter nor call a destructor on the content
4413 ** when it has finished using that result.
4414 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4415 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4416 ** then SQLite makes a copy of the result into space obtained from
4417 ** from [sqlite3_malloc()] before it returns.
4419 ** ^The sqlite3_result_value() interface sets the result of
4420 ** the application-defined function to be a copy the
4421 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
4422 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4423 ** so that the [sqlite3_value] specified in the parameter may change or
4424 ** be deallocated after sqlite3_result_value() returns without harm.
4425 ** ^A [protected sqlite3_value] object may always be used where an
4426 ** [unprotected sqlite3_value] object is required, so either
4427 ** kind of [sqlite3_value] object can be used with this interface.
4429 ** If these routines are called from within the different thread
4430 ** than the one containing the application-defined function that received
4431 ** the [sqlite3_context] pointer, the results are undefined.
4433 SQLITE_API
void sqlite3_result_blob(sqlite3_context
*, const void*, int, void(*)(void*));
4434 SQLITE_API
void sqlite3_result_double(sqlite3_context
*, double);
4435 SQLITE_API
void sqlite3_result_error(sqlite3_context
*, const char*, int);
4436 SQLITE_API
void sqlite3_result_error16(sqlite3_context
*, const void*, int);
4437 SQLITE_API
void sqlite3_result_error_toobig(sqlite3_context
*);
4438 SQLITE_API
void sqlite3_result_error_nomem(sqlite3_context
*);
4439 SQLITE_API
void sqlite3_result_error_code(sqlite3_context
*, int);
4440 SQLITE_API
void sqlite3_result_int(sqlite3_context
*, int);
4441 SQLITE_API
void sqlite3_result_int64(sqlite3_context
*, sqlite3_int64
);
4442 SQLITE_API
void sqlite3_result_null(sqlite3_context
*);
4443 SQLITE_API
void sqlite3_result_text(sqlite3_context
*, const char*, int, void(*)(void*));
4444 SQLITE_API
void sqlite3_result_text16(sqlite3_context
*, const void*, int, void(*)(void*));
4445 SQLITE_API
void sqlite3_result_text16le(sqlite3_context
*, const void*, int,void(*)(void*));
4446 SQLITE_API
void sqlite3_result_text16be(sqlite3_context
*, const void*, int,void(*)(void*));
4447 SQLITE_API
void sqlite3_result_value(sqlite3_context
*, sqlite3_value
*);
4448 SQLITE_API
void sqlite3_result_zeroblob(sqlite3_context
*, int n
);
4451 ** CAPI3REF: Define New Collating Sequences
4453 ** ^These functions add, remove, or modify a [collation] associated
4454 ** with the [database connection] specified as the first argument.
4456 ** ^The name of the collation is a UTF-8 string
4457 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4458 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4459 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4460 ** considered to be the same name.
4462 ** ^(The third argument (eTextRep) must be one of the constants:
4464 ** <li> [SQLITE_UTF8],
4465 ** <li> [SQLITE_UTF16LE],
4466 ** <li> [SQLITE_UTF16BE],
4467 ** <li> [SQLITE_UTF16], or
4468 ** <li> [SQLITE_UTF16_ALIGNED].
4470 ** ^The eTextRep argument determines the encoding of strings passed
4471 ** to the collating function callback, xCallback.
4472 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4473 ** force strings to be UTF16 with native byte order.
4474 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4475 ** on an even byte address.
4477 ** ^The fourth argument, pArg, is an application data pointer that is passed
4478 ** through as the first argument to the collating function callback.
4480 ** ^The fifth argument, xCallback, is a pointer to the collating function.
4481 ** ^Multiple collating functions can be registered using the same name but
4482 ** with different eTextRep parameters and SQLite will use whichever
4483 ** function requires the least amount of data transformation.
4484 ** ^If the xCallback argument is NULL then the collating function is
4485 ** deleted. ^When all collating functions having the same name are deleted,
4486 ** that collation is no longer usable.
4488 ** ^The collating function callback is invoked with a copy of the pArg
4489 ** application data pointer and with two strings in the encoding specified
4490 ** by the eTextRep argument. The collating function must return an
4491 ** integer that is negative, zero, or positive
4492 ** if the first string is less than, equal to, or greater than the second,
4493 ** respectively. A collating function must always return the same answer
4494 ** given the same inputs. If two or more collating functions are registered
4495 ** to the same collation name (using different eTextRep values) then all
4496 ** must give an equivalent answer when invoked with equivalent strings.
4497 ** The collating function must obey the following properties for all
4498 ** strings A, B, and C:
4501 ** <li> If A==B then B==A.
4502 ** <li> If A==B and B==C then A==C.
4503 ** <li> If A<B THEN B>A.
4504 ** <li> If A<B and B<C then A<C.
4507 ** If a collating function fails any of the above constraints and that
4508 ** collating function is registered and used, then the behavior of SQLite
4511 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4512 ** with the addition that the xDestroy callback is invoked on pArg when
4513 ** the collating function is deleted.
4514 ** ^Collating functions are deleted when they are overridden by later
4515 ** calls to the collation creation functions or when the
4516 ** [database connection] is closed using [sqlite3_close()].
4518 ** ^The xDestroy callback is <u>not</u> called if the
4519 ** sqlite3_create_collation_v2() function fails. Applications that invoke
4520 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4521 ** check the return code and dispose of the application data pointer
4522 ** themselves rather than expecting SQLite to deal with it for them.
4523 ** This is different from every other SQLite interface. The inconsistency
4524 ** is unfortunate but cannot be changed without breaking backwards
4527 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4529 SQLITE_API
int sqlite3_create_collation(
4534 int(*xCompare
)(void*,int,const void*,int,const void*)
4536 SQLITE_API
int sqlite3_create_collation_v2(
4541 int(*xCompare
)(void*,int,const void*,int,const void*),
4542 void(*xDestroy
)(void*)
4544 SQLITE_API
int sqlite3_create_collation16(
4549 int(*xCompare
)(void*,int,const void*,int,const void*)
4553 ** CAPI3REF: Collation Needed Callbacks
4555 ** ^To avoid having to register all collation sequences before a database
4556 ** can be used, a single callback function may be registered with the
4557 ** [database connection] to be invoked whenever an undefined collation
4558 ** sequence is required.
4560 ** ^If the function is registered using the sqlite3_collation_needed() API,
4561 ** then it is passed the names of undefined collation sequences as strings
4562 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4563 ** the names are passed as UTF-16 in machine native byte order.
4564 ** ^A call to either function replaces the existing collation-needed callback.
4566 ** ^(When the callback is invoked, the first argument passed is a copy
4567 ** of the second argument to sqlite3_collation_needed() or
4568 ** sqlite3_collation_needed16(). The second argument is the database
4569 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4570 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4571 ** sequence function required. The fourth parameter is the name of the
4572 ** required collation sequence.)^
4574 ** The callback function should register the desired collation using
4575 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4576 ** [sqlite3_create_collation_v2()].
4578 SQLITE_API
int sqlite3_collation_needed(
4581 void(*)(void*,sqlite3
*,int eTextRep
,const char*)
4583 SQLITE_API
int sqlite3_collation_needed16(
4586 void(*)(void*,sqlite3
*,int eTextRep
,const void*)
4589 #ifdef SQLITE_HAS_CODEC
4591 ** Specify the key for an encrypted database. This routine should be
4592 ** called right after sqlite3_open().
4594 ** The code to implement this API is not available in the public release
4597 SQLITE_API
int sqlite3_key(
4598 sqlite3
*db
, /* Database to be rekeyed */
4599 const void *pKey
, int nKey
/* The key */
4601 SQLITE_API
int sqlite3_key_v2(
4602 sqlite3
*db
, /* Database to be rekeyed */
4603 const char *zDbName
, /* Name of the database */
4604 const void *pKey
, int nKey
/* The key */
4608 ** Change the key on an open database. If the current database is not
4609 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
4610 ** database is decrypted.
4612 ** The code to implement this API is not available in the public release
4615 SQLITE_API
int sqlite3_rekey(
4616 sqlite3
*db
, /* Database to be rekeyed */
4617 const void *pKey
, int nKey
/* The new key */
4619 SQLITE_API
int sqlite3_rekey_v2(
4620 sqlite3
*db
, /* Database to be rekeyed */
4621 const char *zDbName
, /* Name of the database */
4622 const void *pKey
, int nKey
/* The new key */
4626 ** Specify the activation key for a SEE database. Unless
4627 ** activated, none of the SEE routines will work.
4629 SQLITE_API
void sqlite3_activate_see(
4630 const char *zPassPhrase
/* Activation phrase */
4634 #ifdef SQLITE_ENABLE_CEROD
4636 ** Specify the activation key for a CEROD database. Unless
4637 ** activated, none of the CEROD routines will work.
4639 SQLITE_API
void sqlite3_activate_cerod(
4640 const char *zPassPhrase
/* Activation phrase */
4645 ** CAPI3REF: Suspend Execution For A Short Time
4647 ** The sqlite3_sleep() function causes the current thread to suspend execution
4648 ** for at least a number of milliseconds specified in its parameter.
4650 ** If the operating system does not support sleep requests with
4651 ** millisecond time resolution, then the time will be rounded up to
4652 ** the nearest second. The number of milliseconds of sleep actually
4653 ** requested from the operating system is returned.
4655 ** ^SQLite implements this interface by calling the xSleep()
4656 ** method of the default [sqlite3_vfs] object. If the xSleep() method
4657 ** of the default VFS is not implemented correctly, or not implemented at
4658 ** all, then the behavior of sqlite3_sleep() may deviate from the description
4659 ** in the previous paragraphs.
4661 SQLITE_API
int sqlite3_sleep(int);
4664 ** CAPI3REF: Name Of The Folder Holding Temporary Files
4666 ** ^(If this global variable is made to point to a string which is
4667 ** the name of a folder (a.k.a. directory), then all temporary files
4668 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4669 ** will be placed in that directory.)^ ^If this variable
4670 ** is a NULL pointer, then SQLite performs a search for an appropriate
4671 ** temporary file directory.
4673 ** It is not safe to read or modify this variable in more than one
4674 ** thread at a time. It is not safe to read or modify this variable
4675 ** if a [database connection] is being used at the same time in a separate
4677 ** It is intended that this variable be set once
4678 ** as part of process initialization and before any SQLite interface
4679 ** routines have been called and that this variable remain unchanged
4682 ** ^The [temp_store_directory pragma] may modify this variable and cause
4683 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4684 ** the [temp_store_directory pragma] always assumes that any string
4685 ** that this variable points to is held in memory obtained from
4686 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4687 ** using [sqlite3_free].
4688 ** Hence, if this variable is modified directly, either it should be
4689 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4690 ** or else the use of the [temp_store_directory pragma] should be avoided.
4692 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
4693 ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
4694 ** features that require the use of temporary files may fail. Here is an
4695 ** example of how to do this using C++ with the Windows Runtime:
4697 ** <blockquote><pre>
4698 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
4699 ** TemporaryFolder->Path->Data();
4700 ** char zPathBuf[MAX_PATH + 1];
4701 ** memset(zPathBuf, 0, sizeof(zPathBuf));
4702 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
4703 ** NULL, NULL);
4704 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
4705 ** </pre></blockquote>
4707 SQLITE_API SQLITE_EXTERN
char *sqlite3_temp_directory
;
4710 ** CAPI3REF: Name Of The Folder Holding Database Files
4712 ** ^(If this global variable is made to point to a string which is
4713 ** the name of a folder (a.k.a. directory), then all database files
4714 ** specified with a relative pathname and created or accessed by
4715 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
4716 ** to be relative to that directory.)^ ^If this variable is a NULL
4717 ** pointer, then SQLite assumes that all database files specified
4718 ** with a relative pathname are relative to the current directory
4719 ** for the process. Only the windows VFS makes use of this global
4720 ** variable; it is ignored by the unix VFS.
4722 ** Changing the value of this variable while a database connection is
4723 ** open can result in a corrupt database.
4725 ** It is not safe to read or modify this variable in more than one
4726 ** thread at a time. It is not safe to read or modify this variable
4727 ** if a [database connection] is being used at the same time in a separate
4729 ** It is intended that this variable be set once
4730 ** as part of process initialization and before any SQLite interface
4731 ** routines have been called and that this variable remain unchanged
4734 ** ^The [data_store_directory pragma] may modify this variable and cause
4735 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4736 ** the [data_store_directory pragma] always assumes that any string
4737 ** that this variable points to is held in memory obtained from
4738 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4739 ** using [sqlite3_free].
4740 ** Hence, if this variable is modified directly, either it should be
4741 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4742 ** or else the use of the [data_store_directory pragma] should be avoided.
4744 SQLITE_API SQLITE_EXTERN
char *sqlite3_data_directory
;
4747 ** CAPI3REF: Test For Auto-Commit Mode
4748 ** KEYWORDS: {autocommit mode}
4750 ** ^The sqlite3_get_autocommit() interface returns non-zero or
4751 ** zero if the given database connection is or is not in autocommit mode,
4752 ** respectively. ^Autocommit mode is on by default.
4753 ** ^Autocommit mode is disabled by a [BEGIN] statement.
4754 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
4756 ** If certain kinds of errors occur on a statement within a multi-statement
4757 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
4758 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
4759 ** transaction might be rolled back automatically. The only way to
4760 ** find out whether SQLite automatically rolled back the transaction after
4761 ** an error is to use this function.
4763 ** If another thread changes the autocommit status of the database
4764 ** connection while this routine is running, then the return value
4767 SQLITE_API
int sqlite3_get_autocommit(sqlite3
*);
4770 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
4772 ** ^The sqlite3_db_handle interface returns the [database connection] handle
4773 ** to which a [prepared statement] belongs. ^The [database connection]
4774 ** returned by sqlite3_db_handle is the same [database connection]
4775 ** that was the first argument
4776 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
4777 ** create the statement in the first place.
4779 SQLITE_API sqlite3
*sqlite3_db_handle(sqlite3_stmt
*);
4782 ** CAPI3REF: Return The Filename For A Database Connection
4784 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
4785 ** associated with database N of connection D. ^The main database file
4786 ** has the name "main". If there is no attached database N on the database
4787 ** connection D, or if database N is a temporary or in-memory database, then
4788 ** a NULL pointer is returned.
4790 ** ^The filename returned by this function is the output of the
4791 ** xFullPathname method of the [VFS]. ^In other words, the filename
4792 ** will be an absolute pathname, even if the filename used
4793 ** to open the database originally was a URI or relative pathname.
4795 SQLITE_API
const char *sqlite3_db_filename(sqlite3
*db
, const char *zDbName
);
4798 ** CAPI3REF: Determine if a database is read-only
4800 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
4801 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
4802 ** the name of a database on connection D.
4804 SQLITE_API
int sqlite3_db_readonly(sqlite3
*db
, const char *zDbName
);
4807 ** CAPI3REF: Find the next prepared statement
4809 ** ^This interface returns a pointer to the next [prepared statement] after
4810 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
4811 ** then this interface returns a pointer to the first prepared statement
4812 ** associated with the database connection pDb. ^If no prepared statement
4813 ** satisfies the conditions of this routine, it returns NULL.
4815 ** The [database connection] pointer D in a call to
4816 ** [sqlite3_next_stmt(D,S)] must refer to an open database
4817 ** connection and in particular must not be a NULL pointer.
4819 SQLITE_API sqlite3_stmt
*sqlite3_next_stmt(sqlite3
*pDb
, sqlite3_stmt
*pStmt
);
4822 ** CAPI3REF: Commit And Rollback Notification Callbacks
4824 ** ^The sqlite3_commit_hook() interface registers a callback
4825 ** function to be invoked whenever a transaction is [COMMIT | committed].
4826 ** ^Any callback set by a previous call to sqlite3_commit_hook()
4827 ** for the same database connection is overridden.
4828 ** ^The sqlite3_rollback_hook() interface registers a callback
4829 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
4830 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
4831 ** for the same database connection is overridden.
4832 ** ^The pArg argument is passed through to the callback.
4833 ** ^If the callback on a commit hook function returns non-zero,
4834 ** then the commit is converted into a rollback.
4836 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
4837 ** return the P argument from the previous call of the same function
4838 ** on the same [database connection] D, or NULL for
4839 ** the first call for each function on D.
4841 ** The commit and rollback hook callbacks are not reentrant.
4842 ** The callback implementation must not do anything that will modify
4843 ** the database connection that invoked the callback. Any actions
4844 ** to modify the database connection must be deferred until after the
4845 ** completion of the [sqlite3_step()] call that triggered the commit
4846 ** or rollback hook in the first place.
4847 ** Note that running any other SQL statements, including SELECT statements,
4848 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
4849 ** the database connections for the meaning of "modify" in this paragraph.
4851 ** ^Registering a NULL function disables the callback.
4853 ** ^When the commit hook callback routine returns zero, the [COMMIT]
4854 ** operation is allowed to continue normally. ^If the commit hook
4855 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
4856 ** ^The rollback hook is invoked on a rollback that results from a commit
4857 ** hook returning non-zero, just as it would be with any other rollback.
4859 ** ^For the purposes of this API, a transaction is said to have been
4860 ** rolled back if an explicit "ROLLBACK" statement is executed, or
4861 ** an error or constraint causes an implicit rollback to occur.
4862 ** ^The rollback callback is not invoked if a transaction is
4863 ** automatically rolled back because the database connection is closed.
4865 ** See also the [sqlite3_update_hook()] interface.
4867 SQLITE_API
void *sqlite3_commit_hook(sqlite3
*, int(*)(void*), void*);
4868 SQLITE_API
void *sqlite3_rollback_hook(sqlite3
*, void(*)(void *), void*);
4871 ** CAPI3REF: Data Change Notification Callbacks
4873 ** ^The sqlite3_update_hook() interface registers a callback function
4874 ** with the [database connection] identified by the first argument
4875 ** to be invoked whenever a row is updated, inserted or deleted in
4877 ** ^Any callback set by a previous call to this function
4878 ** for the same database connection is overridden.
4880 ** ^The second argument is a pointer to the function to invoke when a
4881 ** row is updated, inserted or deleted in a rowid table.
4882 ** ^The first argument to the callback is a copy of the third argument
4883 ** to sqlite3_update_hook().
4884 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
4885 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
4887 ** ^The third and fourth arguments to the callback contain pointers to the
4888 ** database and table name containing the affected row.
4889 ** ^The final callback parameter is the [rowid] of the row.
4890 ** ^In the case of an update, this is the [rowid] after the update takes place.
4892 ** ^(The update hook is not invoked when internal system tables are
4893 ** modified (i.e. sqlite_master and sqlite_sequence).)^
4894 ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
4896 ** ^In the current implementation, the update hook
4897 ** is not invoked when duplication rows are deleted because of an
4898 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
4899 ** invoked when rows are deleted using the [truncate optimization].
4900 ** The exceptions defined in this paragraph might change in a future
4901 ** release of SQLite.
4903 ** The update hook implementation must not do anything that will modify
4904 ** the database connection that invoked the update hook. Any actions
4905 ** to modify the database connection must be deferred until after the
4906 ** completion of the [sqlite3_step()] call that triggered the update hook.
4907 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
4908 ** database connections for the meaning of "modify" in this paragraph.
4910 ** ^The sqlite3_update_hook(D,C,P) function
4911 ** returns the P argument from the previous call
4912 ** on the same [database connection] D, or NULL for
4913 ** the first call on D.
4915 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
4918 SQLITE_API
void *sqlite3_update_hook(
4920 void(*)(void *,int ,char const *,char const *,sqlite3_int64
),
4925 ** CAPI3REF: Enable Or Disable Shared Pager Cache
4927 ** ^(This routine enables or disables the sharing of the database cache
4928 ** and schema data structures between [database connection | connections]
4929 ** to the same database. Sharing is enabled if the argument is true
4930 ** and disabled if the argument is false.)^
4932 ** ^Cache sharing is enabled and disabled for an entire process.
4933 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
4934 ** sharing was enabled or disabled for each thread separately.
4936 ** ^(The cache sharing mode set by this interface effects all subsequent
4937 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
4938 ** Existing database connections continue use the sharing mode
4939 ** that was in effect at the time they were opened.)^
4941 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
4942 ** successfully. An [error code] is returned otherwise.)^
4944 ** ^Shared cache is disabled by default. But this might change in
4945 ** future releases of SQLite. Applications that care about shared
4946 ** cache setting should set it explicitly.
4948 ** This interface is threadsafe on processors where writing a
4949 ** 32-bit integer is atomic.
4951 ** See Also: [SQLite Shared-Cache Mode]
4953 SQLITE_API
int sqlite3_enable_shared_cache(int);
4956 ** CAPI3REF: Attempt To Free Heap Memory
4958 ** ^The sqlite3_release_memory() interface attempts to free N bytes
4959 ** of heap memory by deallocating non-essential memory allocations
4960 ** held by the database library. Memory used to cache database
4961 ** pages to improve performance is an example of non-essential memory.
4962 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
4963 ** which might be more or less than the amount requested.
4964 ** ^The sqlite3_release_memory() routine is a no-op returning zero
4965 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
4967 ** See also: [sqlite3_db_release_memory()]
4969 SQLITE_API
int sqlite3_release_memory(int);
4972 ** CAPI3REF: Free Memory Used By A Database Connection
4974 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
4975 ** memory as possible from database connection D. Unlike the
4976 ** [sqlite3_release_memory()] interface, this interface is in effect even
4977 ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
4980 ** See also: [sqlite3_release_memory()]
4982 SQLITE_API
int sqlite3_db_release_memory(sqlite3
*);
4985 ** CAPI3REF: Impose A Limit On Heap Size
4987 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
4988 ** soft limit on the amount of heap memory that may be allocated by SQLite.
4989 ** ^SQLite strives to keep heap memory utilization below the soft heap
4990 ** limit by reducing the number of pages held in the page cache
4991 ** as heap memory usages approaches the limit.
4992 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
4993 ** below the limit, it will exceed the limit rather than generate
4994 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
4995 ** is advisory only.
4997 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
4998 ** the soft heap limit prior to the call, or negative in the case of an
4999 ** error. ^If the argument N is negative
5000 ** then no change is made to the soft heap limit. Hence, the current
5001 ** size of the soft heap limit can be determined by invoking
5002 ** sqlite3_soft_heap_limit64() with a negative argument.
5004 ** ^If the argument N is zero then the soft heap limit is disabled.
5006 ** ^(The soft heap limit is not enforced in the current implementation
5007 ** if one or more of following conditions are true:
5010 ** <li> The soft heap limit is set to zero.
5011 ** <li> Memory accounting is disabled using a combination of the
5012 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
5013 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
5014 ** <li> An alternative page cache implementation is specified using
5015 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
5016 ** <li> The page cache allocates from its own memory pool supplied
5017 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
5021 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
5022 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
5023 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
5024 ** the soft heap limit is enforced on every memory allocation. Without
5025 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
5026 ** when memory is allocated by the page cache. Testing suggests that because
5027 ** the page cache is the predominate memory user in SQLite, most
5028 ** applications will achieve adequate soft heap limit enforcement without
5029 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5031 ** The circumstances under which SQLite will enforce the soft heap limit may
5032 ** changes in future releases of SQLite.
5034 SQLITE_API sqlite3_int64
sqlite3_soft_heap_limit64(sqlite3_int64 N
);
5037 ** CAPI3REF: Deprecated Soft Heap Limit Interface
5040 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
5041 ** interface. This routine is provided for historical compatibility
5042 ** only. All new applications should use the
5043 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
5045 SQLITE_API SQLITE_DEPRECATED
void sqlite3_soft_heap_limit(int N
);
5049 ** CAPI3REF: Extract Metadata About A Column Of A Table
5051 ** ^This routine returns metadata about a specific column of a specific
5052 ** database table accessible using the [database connection] handle
5053 ** passed as the first function argument.
5055 ** ^The column is identified by the second, third and fourth parameters to
5056 ** this function. ^The second parameter is either the name of the database
5057 ** (i.e. "main", "temp", or an attached database) containing the specified
5058 ** table or NULL. ^If it is NULL, then all attached databases are searched
5059 ** for the table using the same algorithm used by the database engine to
5060 ** resolve unqualified table references.
5062 ** ^The third and fourth parameters to this function are the table and column
5063 ** name of the desired column, respectively. Neither of these parameters
5066 ** ^Metadata is returned by writing to the memory locations passed as the 5th
5067 ** and subsequent parameters to this function. ^Any of these arguments may be
5068 ** NULL, in which case the corresponding element of metadata is omitted.
5071 ** <table border="1">
5072 ** <tr><th> Parameter <th> Output<br>Type <th> Description
5074 ** <tr><td> 5th <td> const char* <td> Data type
5075 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
5076 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
5077 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
5078 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
5082 ** ^The memory pointed to by the character pointers returned for the
5083 ** declaration type and collation sequence is valid only until the next
5084 ** call to any SQLite API function.
5086 ** ^If the specified table is actually a view, an [error code] is returned.
5088 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an
5089 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
5090 ** parameters are set for the explicitly declared column. ^(If there is no
5091 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
5092 ** parameters are set as follows:
5095 ** data type: "INTEGER"
5096 ** collation sequence: "BINARY"
5099 ** auto increment: 0
5102 ** ^(This function may load one or more schemas from database files. If an
5103 ** error occurs during this process, or if the requested table or column
5104 ** cannot be found, an [error code] is returned and an error message left
5105 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
5107 ** ^This API is only available if the library was compiled with the
5108 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
5110 SQLITE_API
int sqlite3_table_column_metadata(
5111 sqlite3
*db
, /* Connection handle */
5112 const char *zDbName
, /* Database name or NULL */
5113 const char *zTableName
, /* Table name */
5114 const char *zColumnName
, /* Column name */
5115 char const **pzDataType
, /* OUTPUT: Declared data type */
5116 char const **pzCollSeq
, /* OUTPUT: Collation sequence name */
5117 int *pNotNull
, /* OUTPUT: True if NOT NULL constraint exists */
5118 int *pPrimaryKey
, /* OUTPUT: True if column part of PK */
5119 int *pAutoinc
/* OUTPUT: True if column is auto-increment */
5123 ** CAPI3REF: Load An Extension
5125 ** ^This interface loads an SQLite extension library from the named file.
5127 ** ^The sqlite3_load_extension() interface attempts to load an
5128 ** [SQLite extension] library contained in the file zFile. If
5129 ** the file cannot be loaded directly, attempts are made to load
5130 ** with various operating-system specific extensions added.
5131 ** So for example, if "samplelib" cannot be loaded, then names like
5132 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
5135 ** ^The entry point is zProc.
5136 ** ^(zProc may be 0, in which case SQLite will try to come up with an
5137 ** entry point name on its own. It first tries "sqlite3_extension_init".
5138 ** If that does not work, it constructs a name "sqlite3_X_init" where the
5139 ** X is consists of the lower-case equivalent of all ASCII alphabetic
5140 ** characters in the filename from the last "/" to the first following
5141 ** "." and omitting any initial "lib".)^
5142 ** ^The sqlite3_load_extension() interface returns
5143 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
5144 ** ^If an error occurs and pzErrMsg is not 0, then the
5145 ** [sqlite3_load_extension()] interface shall attempt to
5146 ** fill *pzErrMsg with error message text stored in memory
5147 ** obtained from [sqlite3_malloc()]. The calling function
5148 ** should free this memory by calling [sqlite3_free()].
5150 ** ^Extension loading must be enabled using
5151 ** [sqlite3_enable_load_extension()] prior to calling this API,
5152 ** otherwise an error will be returned.
5154 ** See also the [load_extension() SQL function].
5156 SQLITE_API
int sqlite3_load_extension(
5157 sqlite3
*db
, /* Load the extension into this database connection */
5158 const char *zFile
, /* Name of the shared library containing extension */
5159 const char *zProc
, /* Entry point. Derived from zFile if 0 */
5160 char **pzErrMsg
/* Put error message here if not 0 */
5164 ** CAPI3REF: Enable Or Disable Extension Loading
5166 ** ^So as not to open security holes in older applications that are
5167 ** unprepared to deal with [extension loading], and as a means of disabling
5168 ** [extension loading] while evaluating user-entered SQL, the following API
5169 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5171 ** ^Extension loading is off by default.
5172 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5173 ** to turn extension loading on and call it with onoff==0 to turn
5174 ** it back off again.
5176 SQLITE_API
int sqlite3_enable_load_extension(sqlite3
*db
, int onoff
);
5179 ** CAPI3REF: Automatically Load Statically Linked Extensions
5181 ** ^This interface causes the xEntryPoint() function to be invoked for
5182 ** each new [database connection] that is created. The idea here is that
5183 ** xEntryPoint() is the entry point for a statically linked [SQLite extension]
5184 ** that is to be automatically loaded into all new database connections.
5186 ** ^(Even though the function prototype shows that xEntryPoint() takes
5187 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
5188 ** arguments and expects and integer result as if the signature of the
5189 ** entry point where as follows:
5191 ** <blockquote><pre>
5192 ** int xEntryPoint(
5193 ** sqlite3 *db,
5194 ** const char **pzErrMsg,
5195 ** const struct sqlite3_api_routines *pThunk
5197 ** </pre></blockquote>)^
5199 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
5200 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
5201 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
5202 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
5203 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
5204 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
5205 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
5207 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
5208 ** on the list of automatic extensions is a harmless no-op. ^No entry point
5209 ** will be called more than once for each database connection that is opened.
5211 ** See also: [sqlite3_reset_auto_extension()]
5212 ** and [sqlite3_cancel_auto_extension()]
5214 SQLITE_API
int sqlite3_auto_extension(void (*xEntryPoint
)(void));
5217 ** CAPI3REF: Cancel Automatic Extension Loading
5219 ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
5220 ** initialization routine X that was registered using a prior call to
5221 ** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)]
5222 ** routine returns 1 if initialization routine X was successfully
5223 ** unregistered and it returns 0 if X was not on the list of initialization
5226 SQLITE_API
int sqlite3_cancel_auto_extension(void (*xEntryPoint
)(void));
5229 ** CAPI3REF: Reset Automatic Extension Loading
5231 ** ^This interface disables all automatic extensions previously
5232 ** registered using [sqlite3_auto_extension()].
5234 SQLITE_API
void sqlite3_reset_auto_extension(void);
5237 ** The interface to the virtual-table mechanism is currently considered
5238 ** to be experimental. The interface might change in incompatible ways.
5239 ** If this is a problem for you, do not use the interface at this time.
5241 ** When the virtual-table mechanism stabilizes, we will declare the
5242 ** interface fixed, support it indefinitely, and remove this comment.
5246 ** Structures used by the virtual table interface
5248 typedef struct sqlite3_vtab sqlite3_vtab
;
5249 typedef struct sqlite3_index_info sqlite3_index_info
;
5250 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor
;
5251 typedef struct sqlite3_module sqlite3_module
;
5254 ** CAPI3REF: Virtual Table Object
5255 ** KEYWORDS: sqlite3_module {virtual table module}
5257 ** This structure, sometimes called a "virtual table module",
5258 ** defines the implementation of a [virtual tables].
5259 ** This structure consists mostly of methods for the module.
5261 ** ^A virtual table module is created by filling in a persistent
5262 ** instance of this structure and passing a pointer to that instance
5263 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
5264 ** ^The registration remains valid until it is replaced by a different
5265 ** module or until the [database connection] closes. The content
5266 ** of this structure must not change while it is registered with
5267 ** any database connection.
5269 struct sqlite3_module
{
5271 int (*xCreate
)(sqlite3
*, void *pAux
,
5272 int argc
, const char *const*argv
,
5273 sqlite3_vtab
**ppVTab
, char**);
5274 int (*xConnect
)(sqlite3
*, void *pAux
,
5275 int argc
, const char *const*argv
,
5276 sqlite3_vtab
**ppVTab
, char**);
5277 int (*xBestIndex
)(sqlite3_vtab
*pVTab
, sqlite3_index_info
*);
5278 int (*xDisconnect
)(sqlite3_vtab
*pVTab
);
5279 int (*xDestroy
)(sqlite3_vtab
*pVTab
);
5280 int (*xOpen
)(sqlite3_vtab
*pVTab
, sqlite3_vtab_cursor
**ppCursor
);
5281 int (*xClose
)(sqlite3_vtab_cursor
*);
5282 int (*xFilter
)(sqlite3_vtab_cursor
*, int idxNum
, const char *idxStr
,
5283 int argc
, sqlite3_value
**argv
);
5284 int (*xNext
)(sqlite3_vtab_cursor
*);
5285 int (*xEof
)(sqlite3_vtab_cursor
*);
5286 int (*xColumn
)(sqlite3_vtab_cursor
*, sqlite3_context
*, int);
5287 int (*xRowid
)(sqlite3_vtab_cursor
*, sqlite3_int64
*pRowid
);
5288 int (*xUpdate
)(sqlite3_vtab
*, int, sqlite3_value
**, sqlite3_int64
*);
5289 int (*xBegin
)(sqlite3_vtab
*pVTab
);
5290 int (*xSync
)(sqlite3_vtab
*pVTab
);
5291 int (*xCommit
)(sqlite3_vtab
*pVTab
);
5292 int (*xRollback
)(sqlite3_vtab
*pVTab
);
5293 int (*xFindFunction
)(sqlite3_vtab
*pVtab
, int nArg
, const char *zName
,
5294 void (**pxFunc
)(sqlite3_context
*,int,sqlite3_value
**),
5296 int (*xRename
)(sqlite3_vtab
*pVtab
, const char *zNew
);
5297 /* The methods above are in version 1 of the sqlite_module object. Those
5298 ** below are for version 2 and greater. */
5299 int (*xSavepoint
)(sqlite3_vtab
*pVTab
, int);
5300 int (*xRelease
)(sqlite3_vtab
*pVTab
, int);
5301 int (*xRollbackTo
)(sqlite3_vtab
*pVTab
, int);
5305 ** CAPI3REF: Virtual Table Indexing Information
5306 ** KEYWORDS: sqlite3_index_info
5308 ** The sqlite3_index_info structure and its substructures is used as part
5309 ** of the [virtual table] interface to
5310 ** pass information into and receive the reply from the [xBestIndex]
5311 ** method of a [virtual table module]. The fields under **Inputs** are the
5312 ** inputs to xBestIndex and are read-only. xBestIndex inserts its
5313 ** results into the **Outputs** fields.
5315 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
5317 ** <blockquote>column OP expr</blockquote>
5319 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is
5320 ** stored in aConstraint[].op using one of the
5321 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
5322 ** ^(The index of the column is stored in
5323 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
5324 ** expr on the right-hand side can be evaluated (and thus the constraint
5325 ** is usable) and false if it cannot.)^
5327 ** ^The optimizer automatically inverts terms of the form "expr OP column"
5328 ** and makes other simplifications to the WHERE clause in an attempt to
5329 ** get as many WHERE clause terms into the form shown above as possible.
5330 ** ^The aConstraint[] array only reports WHERE clause terms that are
5331 ** relevant to the particular virtual table being queried.
5333 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
5334 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
5336 ** The [xBestIndex] method must fill aConstraintUsage[] with information
5337 ** about what parameters to pass to xFilter. ^If argvIndex>0 then
5338 ** the right-hand side of the corresponding aConstraint[] is evaluated
5339 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
5340 ** is true, then the constraint is assumed to be fully handled by the
5341 ** virtual table and is not checked again by SQLite.)^
5343 ** ^The idxNum and idxPtr values are recorded and passed into the
5344 ** [xFilter] method.
5345 ** ^[sqlite3_free()] is used to free idxPtr if and only if
5346 ** needToFreeIdxPtr is true.
5348 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
5349 ** the correct order to satisfy the ORDER BY clause so that no separate
5350 ** sorting step is required.
5352 ** ^The estimatedCost value is an estimate of the cost of a particular
5353 ** strategy. A cost of N indicates that the cost of the strategy is similar
5354 ** to a linear scan of an SQLite table with N rows. A cost of log(N)
5355 ** indicates that the expense of the operation is similar to that of a
5356 ** binary search on a unique indexed field of an SQLite table with N rows.
5358 ** ^The estimatedRows value is an estimate of the number of rows that
5359 ** will be returned by the strategy.
5361 ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
5362 ** structure for SQLite version 3.8.2. If a virtual table extension is
5363 ** used with an SQLite version earlier than 3.8.2, the results of attempting
5364 ** to read or write the estimatedRows field are undefined (but are likely
5365 ** to included crashing the application). The estimatedRows field should
5366 ** therefore only be used if [sqlite3_libversion_number()] returns a
5367 ** value greater than or equal to 3008002.
5369 struct sqlite3_index_info
{
5371 int nConstraint
; /* Number of entries in aConstraint */
5372 struct sqlite3_index_constraint
{
5373 int iColumn
; /* Column on left-hand side of constraint */
5374 unsigned char op
; /* Constraint operator */
5375 unsigned char usable
; /* True if this constraint is usable */
5376 int iTermOffset
; /* Used internally - xBestIndex should ignore */
5377 } *aConstraint
; /* Table of WHERE clause constraints */
5378 int nOrderBy
; /* Number of terms in the ORDER BY clause */
5379 struct sqlite3_index_orderby
{
5380 int iColumn
; /* Column number */
5381 unsigned char desc
; /* True for DESC. False for ASC. */
5382 } *aOrderBy
; /* The ORDER BY clause */
5384 struct sqlite3_index_constraint_usage
{
5385 int argvIndex
; /* if >0, constraint is part of argv to xFilter */
5386 unsigned char omit
; /* Do not code a test for this constraint */
5387 } *aConstraintUsage
;
5388 int idxNum
; /* Number used to identify the index */
5389 char *idxStr
; /* String, possibly obtained from sqlite3_malloc */
5390 int needToFreeIdxStr
; /* Free idxStr using sqlite3_free() if true */
5391 int orderByConsumed
; /* True if output is already ordered */
5392 double estimatedCost
; /* Estimated cost of using this index */
5393 /* Fields below are only available in SQLite 3.8.2 and later */
5394 sqlite3_int64 estimatedRows
; /* Estimated number of rows returned */
5398 ** CAPI3REF: Virtual Table Constraint Operator Codes
5400 ** These macros defined the allowed values for the
5401 ** [sqlite3_index_info].aConstraint[].op field. Each value represents
5402 ** an operator that is part of a constraint term in the wHERE clause of
5403 ** a query that uses a [virtual table].
5405 #define SQLITE_INDEX_CONSTRAINT_EQ 2
5406 #define SQLITE_INDEX_CONSTRAINT_GT 4
5407 #define SQLITE_INDEX_CONSTRAINT_LE 8
5408 #define SQLITE_INDEX_CONSTRAINT_LT 16
5409 #define SQLITE_INDEX_CONSTRAINT_GE 32
5410 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
5413 ** CAPI3REF: Register A Virtual Table Implementation
5415 ** ^These routines are used to register a new [virtual table module] name.
5416 ** ^Module names must be registered before
5417 ** creating a new [virtual table] using the module and before using a
5418 ** preexisting [virtual table] for the module.
5420 ** ^The module name is registered on the [database connection] specified
5421 ** by the first parameter. ^The name of the module is given by the
5422 ** second parameter. ^The third parameter is a pointer to
5423 ** the implementation of the [virtual table module]. ^The fourth
5424 ** parameter is an arbitrary client data pointer that is passed through
5425 ** into the [xCreate] and [xConnect] methods of the virtual table module
5426 ** when a new virtual table is be being created or reinitialized.
5428 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
5429 ** is a pointer to a destructor for the pClientData. ^SQLite will
5430 ** invoke the destructor function (if it is not NULL) when SQLite
5431 ** no longer needs the pClientData pointer. ^The destructor will also
5432 ** be invoked if the call to sqlite3_create_module_v2() fails.
5433 ** ^The sqlite3_create_module()
5434 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
5437 SQLITE_API
int sqlite3_create_module(
5438 sqlite3
*db
, /* SQLite connection to register module with */
5439 const char *zName
, /* Name of the module */
5440 const sqlite3_module
*p
, /* Methods for the module */
5441 void *pClientData
/* Client data for xCreate/xConnect */
5443 SQLITE_API
int sqlite3_create_module_v2(
5444 sqlite3
*db
, /* SQLite connection to register module with */
5445 const char *zName
, /* Name of the module */
5446 const sqlite3_module
*p
, /* Methods for the module */
5447 void *pClientData
, /* Client data for xCreate/xConnect */
5448 void(*xDestroy
)(void*) /* Module destructor function */
5452 ** CAPI3REF: Virtual Table Instance Object
5453 ** KEYWORDS: sqlite3_vtab
5455 ** Every [virtual table module] implementation uses a subclass
5456 ** of this object to describe a particular instance
5457 ** of the [virtual table]. Each subclass will
5458 ** be tailored to the specific needs of the module implementation.
5459 ** The purpose of this superclass is to define certain fields that are
5460 ** common to all module implementations.
5462 ** ^Virtual tables methods can set an error message by assigning a
5463 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
5464 ** take care that any prior string is freed by a call to [sqlite3_free()]
5465 ** prior to assigning a new string to zErrMsg. ^After the error message
5466 ** is delivered up to the client application, the string will be automatically
5467 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
5469 struct sqlite3_vtab
{
5470 const sqlite3_module
*pModule
; /* The module for this virtual table */
5471 int nRef
; /* NO LONGER USED */
5472 char *zErrMsg
; /* Error message from sqlite3_mprintf() */
5473 /* Virtual table implementations will typically add additional fields */
5477 ** CAPI3REF: Virtual Table Cursor Object
5478 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
5480 ** Every [virtual table module] implementation uses a subclass of the
5481 ** following structure to describe cursors that point into the
5482 ** [virtual table] and are used
5483 ** to loop through the virtual table. Cursors are created using the
5484 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
5485 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
5486 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
5487 ** of the module. Each module implementation will define
5488 ** the content of a cursor structure to suit its own needs.
5490 ** This superclass exists in order to define fields of the cursor that
5491 ** are common to all implementations.
5493 struct sqlite3_vtab_cursor
{
5494 sqlite3_vtab
*pVtab
; /* Virtual table of this cursor */
5495 /* Virtual table implementations will typically add additional fields */
5499 ** CAPI3REF: Declare The Schema Of A Virtual Table
5501 ** ^The [xCreate] and [xConnect] methods of a
5502 ** [virtual table module] call this interface
5503 ** to declare the format (the names and datatypes of the columns) of
5504 ** the virtual tables they implement.
5506 SQLITE_API
int sqlite3_declare_vtab(sqlite3
*, const char *zSQL
);
5509 ** CAPI3REF: Overload A Function For A Virtual Table
5511 ** ^(Virtual tables can provide alternative implementations of functions
5512 ** using the [xFindFunction] method of the [virtual table module].
5513 ** But global versions of those functions
5514 ** must exist in order to be overloaded.)^
5516 ** ^(This API makes sure a global version of a function with a particular
5517 ** name and number of parameters exists. If no such function exists
5518 ** before this API is called, a new function is created.)^ ^The implementation
5519 ** of the new function always causes an exception to be thrown. So
5520 ** the new function is not good for anything by itself. Its only
5521 ** purpose is to be a placeholder function that can be overloaded
5522 ** by a [virtual table].
5524 SQLITE_API
int sqlite3_overload_function(sqlite3
*, const char *zFuncName
, int nArg
);
5527 ** The interface to the virtual-table mechanism defined above (back up
5528 ** to a comment remarkably similar to this one) is currently considered
5529 ** to be experimental. The interface might change in incompatible ways.
5530 ** If this is a problem for you, do not use the interface at this time.
5532 ** When the virtual-table mechanism stabilizes, we will declare the
5533 ** interface fixed, support it indefinitely, and remove this comment.
5537 ** CAPI3REF: A Handle To An Open BLOB
5538 ** KEYWORDS: {BLOB handle} {BLOB handles}
5540 ** An instance of this object represents an open BLOB on which
5541 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
5542 ** ^Objects of this type are created by [sqlite3_blob_open()]
5543 ** and destroyed by [sqlite3_blob_close()].
5544 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
5545 ** can be used to read or write small subsections of the BLOB.
5546 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
5548 typedef struct sqlite3_blob sqlite3_blob
;
5551 ** CAPI3REF: Open A BLOB For Incremental I/O
5553 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
5554 ** in row iRow, column zColumn, table zTable in database zDb;
5555 ** in other words, the same BLOB that would be selected by:
5558 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
5561 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
5562 ** and write access. ^If it is zero, the BLOB is opened for read access.
5563 ** ^It is not possible to open a column that is part of an index or primary
5564 ** key for writing. ^If [foreign key constraints] are enabled, it is
5565 ** not possible to open a column that is part of a [child key] for writing.
5567 ** ^Note that the database name is not the filename that contains
5568 ** the database but rather the symbolic name of the database that
5569 ** appears after the AS keyword when the database is connected using [ATTACH].
5570 ** ^For the main database file, the database name is "main".
5571 ** ^For TEMP tables, the database name is "temp".
5573 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
5574 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
5575 ** to be a null pointer.)^
5576 ** ^This function sets the [database connection] error code and message
5577 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
5578 ** functions. ^Note that the *ppBlob variable is always initialized in a
5579 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
5580 ** regardless of the success or failure of this routine.
5582 ** ^(If the row that a BLOB handle points to is modified by an
5583 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
5584 ** then the BLOB handle is marked as "expired".
5585 ** This is true if any column of the row is changed, even a column
5586 ** other than the one the BLOB handle is open on.)^
5587 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
5588 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
5589 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
5590 ** rolled back by the expiration of the BLOB. Such changes will eventually
5591 ** commit if the transaction continues to completion.)^
5593 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
5594 ** the opened blob. ^The size of a blob may not be changed by this
5595 ** interface. Use the [UPDATE] SQL command to change the size of a
5598 ** ^The [sqlite3_blob_open()] interface will fail for a [WITHOUT ROWID]
5599 ** table. Incremental BLOB I/O is not possible on [WITHOUT ROWID] tables.
5601 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
5602 ** and the built-in [zeroblob] SQL function can be used, if desired,
5603 ** to create an empty, zero-filled blob in which to read or write using
5606 ** To avoid a resource leak, every open [BLOB handle] should eventually
5607 ** be released by a call to [sqlite3_blob_close()].
5609 SQLITE_API
int sqlite3_blob_open(
5613 const char *zColumn
,
5616 sqlite3_blob
**ppBlob
5620 ** CAPI3REF: Move a BLOB Handle to a New Row
5622 ** ^This function is used to move an existing blob handle so that it points
5623 ** to a different row of the same database table. ^The new row is identified
5624 ** by the rowid value passed as the second argument. Only the row can be
5625 ** changed. ^The database, table and column on which the blob handle is open
5626 ** remain the same. Moving an existing blob handle to a new row can be
5627 ** faster than closing the existing handle and opening a new one.
5629 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
5630 ** it must exist and there must be either a blob or text value stored in
5631 ** the nominated column.)^ ^If the new row is not present in the table, or if
5632 ** it does not contain a blob or text value, or if another error occurs, an
5633 ** SQLite error code is returned and the blob handle is considered aborted.
5634 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
5635 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
5636 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
5637 ** always returns zero.
5639 ** ^This function sets the database handle error code and message.
5641 SQLITE_API SQLITE_EXPERIMENTAL
int sqlite3_blob_reopen(sqlite3_blob
*, sqlite3_int64
);
5644 ** CAPI3REF: Close A BLOB Handle
5646 ** ^Closes an open [BLOB handle].
5648 ** ^Closing a BLOB shall cause the current transaction to commit
5649 ** if there are no other BLOBs, no pending prepared statements, and the
5650 ** database connection is in [autocommit mode].
5651 ** ^If any writes were made to the BLOB, they might be held in cache
5652 ** until the close operation if they will fit.
5654 ** ^(Closing the BLOB often forces the changes
5655 ** out to disk and so if any I/O errors occur, they will likely occur
5656 ** at the time when the BLOB is closed. Any errors that occur during
5657 ** closing are reported as a non-zero return value.)^
5659 ** ^(The BLOB is closed unconditionally. Even if this routine returns
5660 ** an error code, the BLOB is still closed.)^
5662 ** ^Calling this routine with a null pointer (such as would be returned
5663 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
5665 SQLITE_API
int sqlite3_blob_close(sqlite3_blob
*);
5668 ** CAPI3REF: Return The Size Of An Open BLOB
5670 ** ^Returns the size in bytes of the BLOB accessible via the
5671 ** successfully opened [BLOB handle] in its only argument. ^The
5672 ** incremental blob I/O routines can only read or overwriting existing
5673 ** blob content; they cannot change the size of a blob.
5675 ** This routine only works on a [BLOB handle] which has been created
5676 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5677 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5678 ** to this routine results in undefined and probably undesirable behavior.
5680 SQLITE_API
int sqlite3_blob_bytes(sqlite3_blob
*);
5683 ** CAPI3REF: Read Data From A BLOB Incrementally
5685 ** ^(This function is used to read data from an open [BLOB handle] into a
5686 ** caller-supplied buffer. N bytes of data are copied into buffer Z
5687 ** from the open BLOB, starting at offset iOffset.)^
5689 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5690 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
5691 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
5692 ** ^The size of the blob (and hence the maximum value of N+iOffset)
5693 ** can be determined using the [sqlite3_blob_bytes()] interface.
5695 ** ^An attempt to read from an expired [BLOB handle] fails with an
5696 ** error code of [SQLITE_ABORT].
5698 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
5699 ** Otherwise, an [error code] or an [extended error code] is returned.)^
5701 ** This routine only works on a [BLOB handle] which has been created
5702 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5703 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5704 ** to this routine results in undefined and probably undesirable behavior.
5706 ** See also: [sqlite3_blob_write()].
5708 SQLITE_API
int sqlite3_blob_read(sqlite3_blob
*, void *Z
, int N
, int iOffset
);
5711 ** CAPI3REF: Write Data Into A BLOB Incrementally
5713 ** ^This function is used to write data into an open [BLOB handle] from a
5714 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
5715 ** into the open BLOB, starting at offset iOffset.
5717 ** ^If the [BLOB handle] passed as the first argument was not opened for
5718 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
5719 ** this function returns [SQLITE_READONLY].
5721 ** ^This function may only modify the contents of the BLOB; it is
5722 ** not possible to increase the size of a BLOB using this API.
5723 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5724 ** [SQLITE_ERROR] is returned and no data is written. ^If N is
5725 ** less than zero [SQLITE_ERROR] is returned and no data is written.
5726 ** The size of the BLOB (and hence the maximum value of N+iOffset)
5727 ** can be determined using the [sqlite3_blob_bytes()] interface.
5729 ** ^An attempt to write to an expired [BLOB handle] fails with an
5730 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
5731 ** before the [BLOB handle] expired are not rolled back by the
5732 ** expiration of the handle, though of course those changes might
5733 ** have been overwritten by the statement that expired the BLOB handle
5734 ** or by other independent statements.
5736 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
5737 ** Otherwise, an [error code] or an [extended error code] is returned.)^
5739 ** This routine only works on a [BLOB handle] which has been created
5740 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5741 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5742 ** to this routine results in undefined and probably undesirable behavior.
5744 ** See also: [sqlite3_blob_read()].
5746 SQLITE_API
int sqlite3_blob_write(sqlite3_blob
*, const void *z
, int n
, int iOffset
);
5749 ** CAPI3REF: Virtual File System Objects
5751 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
5752 ** that SQLite uses to interact
5753 ** with the underlying operating system. Most SQLite builds come with a
5754 ** single default VFS that is appropriate for the host computer.
5755 ** New VFSes can be registered and existing VFSes can be unregistered.
5756 ** The following interfaces are provided.
5758 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
5759 ** ^Names are case sensitive.
5760 ** ^Names are zero-terminated UTF-8 strings.
5761 ** ^If there is no match, a NULL pointer is returned.
5762 ** ^If zVfsName is NULL then the default VFS is returned.
5764 ** ^New VFSes are registered with sqlite3_vfs_register().
5765 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
5766 ** ^The same VFS can be registered multiple times without injury.
5767 ** ^To make an existing VFS into the default VFS, register it again
5768 ** with the makeDflt flag set. If two different VFSes with the
5769 ** same name are registered, the behavior is undefined. If a
5770 ** VFS is registered with a name that is NULL or an empty string,
5771 ** then the behavior is undefined.
5773 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
5774 ** ^(If the default VFS is unregistered, another VFS is chosen as
5775 ** the default. The choice for the new VFS is arbitrary.)^
5777 SQLITE_API sqlite3_vfs
*sqlite3_vfs_find(const char *zVfsName
);
5778 SQLITE_API
int sqlite3_vfs_register(sqlite3_vfs
*, int makeDflt
);
5779 SQLITE_API
int sqlite3_vfs_unregister(sqlite3_vfs
*);
5782 ** CAPI3REF: Mutexes
5784 ** The SQLite core uses these routines for thread
5785 ** synchronization. Though they are intended for internal
5786 ** use by SQLite, code that links against SQLite is
5787 ** permitted to use any of these routines.
5789 ** The SQLite source code contains multiple implementations
5790 ** of these mutex routines. An appropriate implementation
5791 ** is selected automatically at compile-time. ^(The following
5792 ** implementations are available in the SQLite core:
5795 ** <li> SQLITE_MUTEX_PTHREADS
5796 ** <li> SQLITE_MUTEX_W32
5797 ** <li> SQLITE_MUTEX_NOOP
5800 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
5801 ** that does no real locking and is appropriate for use in
5802 ** a single-threaded application. ^The SQLITE_MUTEX_PTHREADS and
5803 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
5806 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
5807 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
5808 ** implementation is included with the library. In this case the
5809 ** application must supply a custom mutex implementation using the
5810 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
5811 ** before calling sqlite3_initialize() or any other public sqlite3_
5812 ** function that calls sqlite3_initialize().)^
5814 ** ^The sqlite3_mutex_alloc() routine allocates a new
5815 ** mutex and returns a pointer to it. ^If it returns NULL
5816 ** that means that a mutex could not be allocated. ^SQLite
5817 ** will unwind its stack and return an error. ^(The argument
5818 ** to sqlite3_mutex_alloc() is one of these integer constants:
5821 ** <li> SQLITE_MUTEX_FAST
5822 ** <li> SQLITE_MUTEX_RECURSIVE
5823 ** <li> SQLITE_MUTEX_STATIC_MASTER
5824 ** <li> SQLITE_MUTEX_STATIC_MEM
5825 ** <li> SQLITE_MUTEX_STATIC_MEM2
5826 ** <li> SQLITE_MUTEX_STATIC_PRNG
5827 ** <li> SQLITE_MUTEX_STATIC_LRU
5828 ** <li> SQLITE_MUTEX_STATIC_LRU2
5831 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
5832 ** cause sqlite3_mutex_alloc() to create
5833 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
5834 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
5835 ** The mutex implementation does not need to make a distinction
5836 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
5837 ** not want to. ^SQLite will only request a recursive mutex in
5838 ** cases where it really needs one. ^If a faster non-recursive mutex
5839 ** implementation is available on the host platform, the mutex subsystem
5840 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
5842 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
5843 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
5844 ** a pointer to a static preexisting mutex. ^Six static mutexes are
5845 ** used by the current version of SQLite. Future versions of SQLite
5846 ** may add additional static mutexes. Static mutexes are for internal
5847 ** use by SQLite only. Applications that use SQLite mutexes should
5848 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
5849 ** SQLITE_MUTEX_RECURSIVE.
5851 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
5852 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
5853 ** returns a different mutex on every call. ^But for the static
5854 ** mutex types, the same mutex is returned on every call that has
5855 ** the same type number.
5857 ** ^The sqlite3_mutex_free() routine deallocates a previously
5858 ** allocated dynamic mutex. ^SQLite is careful to deallocate every
5859 ** dynamic mutex that it allocates. The dynamic mutexes must not be in
5860 ** use when they are deallocated. Attempting to deallocate a static
5861 ** mutex results in undefined behavior. ^SQLite never deallocates
5864 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
5865 ** to enter a mutex. ^If another thread is already within the mutex,
5866 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
5867 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
5868 ** upon successful entry. ^(Mutexes created using
5869 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
5870 ** In such cases the,
5871 ** mutex must be exited an equal number of times before another thread
5872 ** can enter.)^ ^(If the same thread tries to enter any other
5873 ** kind of mutex more than once, the behavior is undefined.
5874 ** SQLite will never exhibit
5875 ** such behavior in its own use of mutexes.)^
5877 ** ^(Some systems (for example, Windows 95) do not support the operation
5878 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
5879 ** will always return SQLITE_BUSY. The SQLite core only ever uses
5880 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
5882 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
5883 ** previously entered by the same thread. ^(The behavior
5884 ** is undefined if the mutex is not currently entered by the
5885 ** calling thread or is not currently allocated. SQLite will
5886 ** never do either.)^
5888 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
5889 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
5890 ** behave as no-ops.
5892 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
5894 SQLITE_API sqlite3_mutex
*sqlite3_mutex_alloc(int);
5895 SQLITE_API
void sqlite3_mutex_free(sqlite3_mutex
*);
5896 SQLITE_API
void sqlite3_mutex_enter(sqlite3_mutex
*);
5897 SQLITE_API
int sqlite3_mutex_try(sqlite3_mutex
*);
5898 SQLITE_API
void sqlite3_mutex_leave(sqlite3_mutex
*);
5901 ** CAPI3REF: Mutex Methods Object
5903 ** An instance of this structure defines the low-level routines
5904 ** used to allocate and use mutexes.
5906 ** Usually, the default mutex implementations provided by SQLite are
5907 ** sufficient, however the user has the option of substituting a custom
5908 ** implementation for specialized deployments or systems for which SQLite
5909 ** does not provide a suitable implementation. In this case, the user
5910 ** creates and populates an instance of this structure to pass
5911 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
5912 ** Additionally, an instance of this structure can be used as an
5913 ** output variable when querying the system for the current mutex
5914 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
5916 ** ^The xMutexInit method defined by this structure is invoked as
5917 ** part of system initialization by the sqlite3_initialize() function.
5918 ** ^The xMutexInit routine is called by SQLite exactly once for each
5919 ** effective call to [sqlite3_initialize()].
5921 ** ^The xMutexEnd method defined by this structure is invoked as
5922 ** part of system shutdown by the sqlite3_shutdown() function. The
5923 ** implementation of this method is expected to release all outstanding
5924 ** resources obtained by the mutex methods implementation, especially
5925 ** those obtained by the xMutexInit method. ^The xMutexEnd()
5926 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
5928 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
5929 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
5930 ** xMutexNotheld) implement the following interfaces (respectively):
5933 ** <li> [sqlite3_mutex_alloc()] </li>
5934 ** <li> [sqlite3_mutex_free()] </li>
5935 ** <li> [sqlite3_mutex_enter()] </li>
5936 ** <li> [sqlite3_mutex_try()] </li>
5937 ** <li> [sqlite3_mutex_leave()] </li>
5938 ** <li> [sqlite3_mutex_held()] </li>
5939 ** <li> [sqlite3_mutex_notheld()] </li>
5942 ** The only difference is that the public sqlite3_XXX functions enumerated
5943 ** above silently ignore any invocations that pass a NULL pointer instead
5944 ** of a valid mutex handle. The implementations of the methods defined
5945 ** by this structure are not required to handle this case, the results
5946 ** of passing a NULL pointer instead of a valid mutex handle are undefined
5947 ** (i.e. it is acceptable to provide an implementation that segfaults if
5948 ** it is passed a NULL pointer).
5950 ** The xMutexInit() method must be threadsafe. ^It must be harmless to
5951 ** invoke xMutexInit() multiple times within the same process and without
5952 ** intervening calls to xMutexEnd(). Second and subsequent calls to
5953 ** xMutexInit() must be no-ops.
5955 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
5956 ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory
5957 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
5958 ** memory allocation for a fast or recursive mutex.
5960 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
5961 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
5962 ** If xMutexInit fails in any way, it is expected to clean up after itself
5963 ** prior to returning.
5965 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods
;
5966 struct sqlite3_mutex_methods
{
5967 int (*xMutexInit
)(void);
5968 int (*xMutexEnd
)(void);
5969 sqlite3_mutex
*(*xMutexAlloc
)(int);
5970 void (*xMutexFree
)(sqlite3_mutex
*);
5971 void (*xMutexEnter
)(sqlite3_mutex
*);
5972 int (*xMutexTry
)(sqlite3_mutex
*);
5973 void (*xMutexLeave
)(sqlite3_mutex
*);
5974 int (*xMutexHeld
)(sqlite3_mutex
*);
5975 int (*xMutexNotheld
)(sqlite3_mutex
*);
5979 ** CAPI3REF: Mutex Verification Routines
5981 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
5982 ** are intended for use inside assert() statements. ^The SQLite core
5983 ** never uses these routines except inside an assert() and applications
5984 ** are advised to follow the lead of the core. ^The SQLite core only
5985 ** provides implementations for these routines when it is compiled
5986 ** with the SQLITE_DEBUG flag. ^External mutex implementations
5987 ** are only required to provide these routines if SQLITE_DEBUG is
5988 ** defined and if NDEBUG is not defined.
5990 ** ^These routines should return true if the mutex in their argument
5991 ** is held or not held, respectively, by the calling thread.
5993 ** ^The implementation is not required to provide versions of these
5994 ** routines that actually work. If the implementation does not provide working
5995 ** versions of these routines, it should at least provide stubs that always
5996 ** return true so that one does not get spurious assertion failures.
5998 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
5999 ** the routine should return 1. This seems counter-intuitive since
6000 ** clearly the mutex cannot be held if it does not exist. But
6001 ** the reason the mutex does not exist is because the build is not
6002 ** using mutexes. And we do not want the assert() containing the
6003 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
6004 ** the appropriate thing to do. ^The sqlite3_mutex_notheld()
6005 ** interface should also return 1 when given a NULL pointer.
6008 SQLITE_API
int sqlite3_mutex_held(sqlite3_mutex
*);
6009 SQLITE_API
int sqlite3_mutex_notheld(sqlite3_mutex
*);
6013 ** CAPI3REF: Mutex Types
6015 ** The [sqlite3_mutex_alloc()] interface takes a single argument
6016 ** which is one of these integer constants.
6018 ** The set of static mutexes may change from one SQLite release to the
6019 ** next. Applications that override the built-in mutex logic must be
6020 ** prepared to accommodate additional static mutexes.
6022 #define SQLITE_MUTEX_FAST 0
6023 #define SQLITE_MUTEX_RECURSIVE 1
6024 #define SQLITE_MUTEX_STATIC_MASTER 2
6025 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
6026 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
6027 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
6028 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */
6029 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
6030 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
6031 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
6034 ** CAPI3REF: Retrieve the mutex for a database connection
6036 ** ^This interface returns a pointer the [sqlite3_mutex] object that
6037 ** serializes access to the [database connection] given in the argument
6038 ** when the [threading mode] is Serialized.
6039 ** ^If the [threading mode] is Single-thread or Multi-thread then this
6040 ** routine returns a NULL pointer.
6042 SQLITE_API sqlite3_mutex
*sqlite3_db_mutex(sqlite3
*);
6045 ** CAPI3REF: Low-Level Control Of Database Files
6047 ** ^The [sqlite3_file_control()] interface makes a direct call to the
6048 ** xFileControl method for the [sqlite3_io_methods] object associated
6049 ** with a particular database identified by the second argument. ^The
6050 ** name of the database is "main" for the main database or "temp" for the
6051 ** TEMP database, or the name that appears after the AS keyword for
6052 ** databases that are added using the [ATTACH] SQL command.
6053 ** ^A NULL pointer can be used in place of "main" to refer to the
6054 ** main database file.
6055 ** ^The third and fourth parameters to this routine
6056 ** are passed directly through to the second and third parameters of
6057 ** the xFileControl method. ^The return value of the xFileControl
6058 ** method becomes the return value of this routine.
6060 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
6061 ** a pointer to the underlying [sqlite3_file] object to be written into
6062 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER
6063 ** case is a short-circuit path which does not actually invoke the
6064 ** underlying sqlite3_io_methods.xFileControl method.
6066 ** ^If the second parameter (zDbName) does not match the name of any
6067 ** open database file, then SQLITE_ERROR is returned. ^This error
6068 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
6069 ** or [sqlite3_errmsg()]. The underlying xFileControl method might
6070 ** also return SQLITE_ERROR. There is no way to distinguish between
6071 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
6072 ** xFileControl method.
6074 ** See also: [SQLITE_FCNTL_LOCKSTATE]
6076 SQLITE_API
int sqlite3_file_control(sqlite3
*, const char *zDbName
, int op
, void*);
6079 ** CAPI3REF: Testing Interface
6081 ** ^The sqlite3_test_control() interface is used to read out internal
6082 ** state of SQLite and to inject faults into SQLite for testing
6083 ** purposes. ^The first parameter is an operation code that determines
6084 ** the number, meaning, and operation of all subsequent parameters.
6086 ** This interface is not for use by applications. It exists solely
6087 ** for verifying the correct operation of the SQLite library. Depending
6088 ** on how the SQLite library is compiled, this interface might not exist.
6090 ** The details of the operation codes, their meanings, the parameters
6091 ** they take, and what they do are all subject to change without notice.
6092 ** Unlike most of the SQLite API, this function is not guaranteed to
6093 ** operate consistently from one release to the next.
6095 SQLITE_API
int sqlite3_test_control(int op
, ...);
6098 ** CAPI3REF: Testing Interface Operation Codes
6100 ** These constants are the valid operation code parameters used
6101 ** as the first argument to [sqlite3_test_control()].
6103 ** These parameters and their meanings are subject to change
6104 ** without notice. These values are for testing purposes only.
6105 ** Applications should not use any of these parameters or the
6106 ** [sqlite3_test_control()] interface.
6108 #define SQLITE_TESTCTRL_FIRST 5
6109 #define SQLITE_TESTCTRL_PRNG_SAVE 5
6110 #define SQLITE_TESTCTRL_PRNG_RESTORE 6
6111 #define SQLITE_TESTCTRL_PRNG_RESET 7
6112 #define SQLITE_TESTCTRL_BITVEC_TEST 8
6113 #define SQLITE_TESTCTRL_FAULT_INSTALL 9
6114 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
6115 #define SQLITE_TESTCTRL_PENDING_BYTE 11
6116 #define SQLITE_TESTCTRL_ASSERT 12
6117 #define SQLITE_TESTCTRL_ALWAYS 13
6118 #define SQLITE_TESTCTRL_RESERVE 14
6119 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
6120 #define SQLITE_TESTCTRL_ISKEYWORD 16
6121 #define SQLITE_TESTCTRL_SCRATCHMALLOC 17
6122 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
6123 #define SQLITE_TESTCTRL_EXPLAIN_STMT 19
6124 #define SQLITE_TESTCTRL_NEVER_CORRUPT 20
6125 #define SQLITE_TESTCTRL_LAST 20
6128 ** CAPI3REF: SQLite Runtime Status
6130 ** ^This interface is used to retrieve runtime status information
6131 ** about the performance of SQLite, and optionally to reset various
6132 ** highwater marks. ^The first argument is an integer code for
6133 ** the specific parameter to measure. ^(Recognized integer codes
6134 ** are of the form [status parameters | SQLITE_STATUS_...].)^
6135 ** ^The current value of the parameter is returned into *pCurrent.
6136 ** ^The highest recorded value is returned in *pHighwater. ^If the
6137 ** resetFlag is true, then the highest record value is reset after
6138 ** *pHighwater is written. ^(Some parameters do not record the highest
6139 ** value. For those parameters
6140 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
6141 ** ^(Other parameters record only the highwater mark and not the current
6142 ** value. For these latter parameters nothing is written into *pCurrent.)^
6144 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a
6145 ** non-zero [error code] on failure.
6147 ** This routine is threadsafe but is not atomic. This routine can be
6148 ** called while other threads are running the same or different SQLite
6149 ** interfaces. However the values returned in *pCurrent and
6150 ** *pHighwater reflect the status of SQLite at different points in time
6151 ** and it is possible that another thread might change the parameter
6152 ** in between the times when *pCurrent and *pHighwater are written.
6154 ** See also: [sqlite3_db_status()]
6156 SQLITE_API
int sqlite3_status(int op
, int *pCurrent
, int *pHighwater
, int resetFlag
);
6160 ** CAPI3REF: Status Parameters
6161 ** KEYWORDS: {status parameters}
6163 ** These integer constants designate various run-time status parameters
6164 ** that can be returned by [sqlite3_status()].
6167 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
6168 ** <dd>This parameter is the current amount of memory checked out
6169 ** using [sqlite3_malloc()], either directly or indirectly. The
6170 ** figure includes calls made to [sqlite3_malloc()] by the application
6171 ** and internal memory usage by the SQLite library. Scratch memory
6172 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
6173 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
6174 ** this parameter. The amount returned is the sum of the allocation
6175 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
6177 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
6178 ** <dd>This parameter records the largest memory allocation request
6179 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
6180 ** internal equivalents). Only the value returned in the
6181 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6182 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6184 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
6185 ** <dd>This parameter records the number of separate memory allocations
6186 ** currently checked out.</dd>)^
6188 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
6189 ** <dd>This parameter returns the number of pages used out of the
6190 ** [pagecache memory allocator] that was configured using
6191 ** [SQLITE_CONFIG_PAGECACHE]. The
6192 ** value returned is in pages, not in bytes.</dd>)^
6194 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
6195 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
6196 ** <dd>This parameter returns the number of bytes of page cache
6197 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
6198 ** buffer and where forced to overflow to [sqlite3_malloc()]. The
6199 ** returned value includes allocations that overflowed because they
6200 ** where too large (they were larger than the "sz" parameter to
6201 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
6202 ** no space was left in the page cache.</dd>)^
6204 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
6205 ** <dd>This parameter records the largest memory allocation request
6206 ** handed to [pagecache memory allocator]. Only the value returned in the
6207 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6208 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6210 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
6211 ** <dd>This parameter returns the number of allocations used out of the
6212 ** [scratch memory allocator] configured using
6213 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not
6214 ** in bytes. Since a single thread may only have one scratch allocation
6215 ** outstanding at time, this parameter also reports the number of threads
6216 ** using scratch memory at the same time.</dd>)^
6218 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
6219 ** <dd>This parameter returns the number of bytes of scratch memory
6220 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
6221 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values
6222 ** returned include overflows because the requested allocation was too
6223 ** larger (that is, because the requested allocation was larger than the
6224 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
6225 ** slots were available.
6228 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
6229 ** <dd>This parameter records the largest memory allocation request
6230 ** handed to [scratch memory allocator]. Only the value returned in the
6231 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6232 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6234 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
6235 ** <dd>This parameter records the deepest parser stack. It is only
6236 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
6239 ** New status parameters may be added from time to time.
6241 #define SQLITE_STATUS_MEMORY_USED 0
6242 #define SQLITE_STATUS_PAGECACHE_USED 1
6243 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
6244 #define SQLITE_STATUS_SCRATCH_USED 3
6245 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4
6246 #define SQLITE_STATUS_MALLOC_SIZE 5
6247 #define SQLITE_STATUS_PARSER_STACK 6
6248 #define SQLITE_STATUS_PAGECACHE_SIZE 7
6249 #define SQLITE_STATUS_SCRATCH_SIZE 8
6250 #define SQLITE_STATUS_MALLOC_COUNT 9
6253 ** CAPI3REF: Database Connection Status
6255 ** ^This interface is used to retrieve runtime status information
6256 ** about a single [database connection]. ^The first argument is the
6257 ** database connection object to be interrogated. ^The second argument
6258 ** is an integer constant, taken from the set of
6259 ** [SQLITE_DBSTATUS options], that
6260 ** determines the parameter to interrogate. The set of
6261 ** [SQLITE_DBSTATUS options] is likely
6262 ** to grow in future releases of SQLite.
6264 ** ^The current value of the requested parameter is written into *pCur
6265 ** and the highest instantaneous value is written into *pHiwtr. ^If
6266 ** the resetFlg is true, then the highest instantaneous value is
6267 ** reset back down to the current value.
6269 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
6270 ** non-zero [error code] on failure.
6272 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
6274 SQLITE_API
int sqlite3_db_status(sqlite3
*, int op
, int *pCur
, int *pHiwtr
, int resetFlg
);
6277 ** CAPI3REF: Status Parameters for database connections
6278 ** KEYWORDS: {SQLITE_DBSTATUS options}
6280 ** These constants are the available integer "verbs" that can be passed as
6281 ** the second argument to the [sqlite3_db_status()] interface.
6283 ** New verbs may be added in future releases of SQLite. Existing verbs
6284 ** might be discontinued. Applications should check the return code from
6285 ** [sqlite3_db_status()] to make sure that the call worked.
6286 ** The [sqlite3_db_status()] interface will return a non-zero error code
6287 ** if a discontinued or unsupported verb is invoked.
6290 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
6291 ** <dd>This parameter returns the number of lookaside memory slots currently
6292 ** checked out.</dd>)^
6294 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
6295 ** <dd>This parameter returns the number malloc attempts that were
6296 ** satisfied using lookaside memory. Only the high-water value is meaningful;
6297 ** the current value is always zero.)^
6299 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
6300 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
6301 ** <dd>This parameter returns the number malloc attempts that might have
6302 ** been satisfied using lookaside memory but failed due to the amount of
6303 ** memory requested being larger than the lookaside slot size.
6304 ** Only the high-water value is meaningful;
6305 ** the current value is always zero.)^
6307 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
6308 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
6309 ** <dd>This parameter returns the number malloc attempts that might have
6310 ** been satisfied using lookaside memory but failed due to all lookaside
6311 ** memory already being in use.
6312 ** Only the high-water value is meaningful;
6313 ** the current value is always zero.)^
6315 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
6316 ** <dd>This parameter returns the approximate number of of bytes of heap
6317 ** memory used by all pager caches associated with the database connection.)^
6318 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
6320 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
6321 ** <dd>This parameter returns the approximate number of of bytes of heap
6322 ** memory used to store the schema for all databases associated
6323 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
6324 ** ^The full amount of memory used by the schemas is reported, even if the
6325 ** schema memory is shared with other database connections due to
6326 ** [shared cache mode] being enabled.
6327 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
6329 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
6330 ** <dd>This parameter returns the approximate number of of bytes of heap
6331 ** and lookaside memory used by all prepared statements associated with
6332 ** the database connection.)^
6333 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
6336 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
6337 ** <dd>This parameter returns the number of pager cache hits that have
6338 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
6342 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
6343 ** <dd>This parameter returns the number of pager cache misses that have
6344 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
6348 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
6349 ** <dd>This parameter returns the number of dirty cache entries that have
6350 ** been written to disk. Specifically, the number of pages written to the
6351 ** wal file in wal mode databases, or the number of pages written to the
6352 ** database file in rollback mode databases. Any pages written as part of
6353 ** transaction rollback or database recovery operations are not included.
6354 ** If an IO or other error occurs while writing a page to disk, the effect
6355 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
6356 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
6359 ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
6360 ** <dd>This parameter returns zero for the current value if and only if
6361 ** all foreign key constraints (deferred or immediate) have been
6362 ** resolved.)^ ^The highwater mark is always 0.
6366 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
6367 #define SQLITE_DBSTATUS_CACHE_USED 1
6368 #define SQLITE_DBSTATUS_SCHEMA_USED 2
6369 #define SQLITE_DBSTATUS_STMT_USED 3
6370 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
6371 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
6372 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
6373 #define SQLITE_DBSTATUS_CACHE_HIT 7
6374 #define SQLITE_DBSTATUS_CACHE_MISS 8
6375 #define SQLITE_DBSTATUS_CACHE_WRITE 9
6376 #define SQLITE_DBSTATUS_DEFERRED_FKS 10
6377 #define SQLITE_DBSTATUS_MAX 10 /* Largest defined DBSTATUS */
6381 ** CAPI3REF: Prepared Statement Status
6383 ** ^(Each prepared statement maintains various
6384 ** [SQLITE_STMTSTATUS counters] that measure the number
6385 ** of times it has performed specific operations.)^ These counters can
6386 ** be used to monitor the performance characteristics of the prepared
6387 ** statements. For example, if the number of table steps greatly exceeds
6388 ** the number of table searches or result rows, that would tend to indicate
6389 ** that the prepared statement is using a full table scan rather than
6392 ** ^(This interface is used to retrieve and reset counter values from
6393 ** a [prepared statement]. The first argument is the prepared statement
6394 ** object to be interrogated. The second argument
6395 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
6396 ** to be interrogated.)^
6397 ** ^The current value of the requested counter is returned.
6398 ** ^If the resetFlg is true, then the counter is reset to zero after this
6399 ** interface call returns.
6401 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
6403 SQLITE_API
int sqlite3_stmt_status(sqlite3_stmt
*, int op
,int resetFlg
);
6406 ** CAPI3REF: Status Parameters for prepared statements
6407 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
6409 ** These preprocessor macros define integer codes that name counter
6410 ** values associated with the [sqlite3_stmt_status()] interface.
6411 ** The meanings of the various counters are as follows:
6414 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
6415 ** <dd>^This is the number of times that SQLite has stepped forward in
6416 ** a table as part of a full table scan. Large numbers for this counter
6417 ** may indicate opportunities for performance improvement through
6418 ** careful use of indices.</dd>
6420 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
6421 ** <dd>^This is the number of sort operations that have occurred.
6422 ** A non-zero value in this counter may indicate an opportunity to
6423 ** improvement performance through careful use of indices.</dd>
6425 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
6426 ** <dd>^This is the number of rows inserted into transient indices that
6427 ** were created automatically in order to help joins run faster.
6428 ** A non-zero value in this counter may indicate an opportunity to
6429 ** improvement performance by adding permanent indices that do not
6430 ** need to be reinitialized each time the statement is run.</dd>
6432 ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
6433 ** <dd>^This is the number of virtual machine operations executed
6434 ** by the prepared statement if that number is less than or equal
6435 ** to 2147483647. The number of virtual machine operations can be
6436 ** used as a proxy for the total work done by the prepared statement.
6437 ** If the number of virtual machine operations exceeds 2147483647
6438 ** then the value returned by this statement status code is undefined.
6442 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
6443 #define SQLITE_STMTSTATUS_SORT 2
6444 #define SQLITE_STMTSTATUS_AUTOINDEX 3
6445 #define SQLITE_STMTSTATUS_VM_STEP 4
6448 ** CAPI3REF: Custom Page Cache Object
6450 ** The sqlite3_pcache type is opaque. It is implemented by
6451 ** the pluggable module. The SQLite core has no knowledge of
6452 ** its size or internal structure and never deals with the
6453 ** sqlite3_pcache object except by holding and passing pointers
6456 ** See [sqlite3_pcache_methods2] for additional information.
6458 typedef struct sqlite3_pcache sqlite3_pcache
;
6461 ** CAPI3REF: Custom Page Cache Object
6463 ** The sqlite3_pcache_page object represents a single page in the
6464 ** page cache. The page cache will allocate instances of this
6465 ** object. Various methods of the page cache use pointers to instances
6466 ** of this object as parameters or as their return value.
6468 ** See [sqlite3_pcache_methods2] for additional information.
6470 typedef struct sqlite3_pcache_page sqlite3_pcache_page
;
6471 struct sqlite3_pcache_page
{
6472 void *pBuf
; /* The content of the page */
6473 void *pExtra
; /* Extra information associated with the page */
6477 ** CAPI3REF: Application Defined Page Cache.
6478 ** KEYWORDS: {page cache}
6480 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
6481 ** register an alternative page cache implementation by passing in an
6482 ** instance of the sqlite3_pcache_methods2 structure.)^
6483 ** In many applications, most of the heap memory allocated by
6484 ** SQLite is used for the page cache.
6485 ** By implementing a
6486 ** custom page cache using this API, an application can better control
6487 ** the amount of memory consumed by SQLite, the way in which
6488 ** that memory is allocated and released, and the policies used to
6489 ** determine exactly which parts of a database file are cached and for
6492 ** The alternative page cache mechanism is an
6493 ** extreme measure that is only needed by the most demanding applications.
6494 ** The built-in page cache is recommended for most uses.
6496 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
6497 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
6498 ** the application may discard the parameter after the call to
6499 ** [sqlite3_config()] returns.)^
6501 ** [[the xInit() page cache method]]
6502 ** ^(The xInit() method is called once for each effective
6503 ** call to [sqlite3_initialize()])^
6504 ** (usually only once during the lifetime of the process). ^(The xInit()
6505 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
6506 ** The intent of the xInit() method is to set up global data structures
6507 ** required by the custom page cache implementation.
6508 ** ^(If the xInit() method is NULL, then the
6509 ** built-in default page cache is used instead of the application defined
6512 ** [[the xShutdown() page cache method]]
6513 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
6514 ** It can be used to clean up
6515 ** any outstanding resources before process shutdown, if required.
6516 ** ^The xShutdown() method may be NULL.
6518 ** ^SQLite automatically serializes calls to the xInit method,
6519 ** so the xInit method need not be threadsafe. ^The
6520 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
6521 ** not need to be threadsafe either. All other methods must be threadsafe
6522 ** in multithreaded applications.
6524 ** ^SQLite will never invoke xInit() more than once without an intervening
6525 ** call to xShutdown().
6527 ** [[the xCreate() page cache methods]]
6528 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
6529 ** SQLite will typically create one cache instance for each open database file,
6530 ** though this is not guaranteed. ^The
6531 ** first parameter, szPage, is the size in bytes of the pages that must
6532 ** be allocated by the cache. ^szPage will always a power of two. ^The
6533 ** second parameter szExtra is a number of bytes of extra storage
6534 ** associated with each page cache entry. ^The szExtra parameter will
6535 ** a number less than 250. SQLite will use the
6536 ** extra szExtra bytes on each page to store metadata about the underlying
6537 ** database page on disk. The value passed into szExtra depends
6538 ** on the SQLite version, the target platform, and how SQLite was compiled.
6539 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
6540 ** created will be used to cache database pages of a file stored on disk, or
6541 ** false if it is used for an in-memory database. The cache implementation
6542 ** does not have to do anything special based with the value of bPurgeable;
6543 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
6544 ** never invoke xUnpin() except to deliberately delete a page.
6545 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
6546 ** false will always have the "discard" flag set to true.
6547 ** ^Hence, a cache created with bPurgeable false will
6548 ** never contain any unpinned pages.
6550 ** [[the xCachesize() page cache method]]
6551 ** ^(The xCachesize() method may be called at any time by SQLite to set the
6552 ** suggested maximum cache-size (number of pages stored by) the cache
6553 ** instance passed as the first argument. This is the value configured using
6554 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
6555 ** parameter, the implementation is not required to do anything with this
6556 ** value; it is advisory only.
6558 ** [[the xPagecount() page cache methods]]
6559 ** The xPagecount() method must return the number of pages currently
6560 ** stored in the cache, both pinned and unpinned.
6562 ** [[the xFetch() page cache methods]]
6563 ** The xFetch() method locates a page in the cache and returns a pointer to
6564 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
6565 ** The pBuf element of the returned sqlite3_pcache_page object will be a
6566 ** pointer to a buffer of szPage bytes used to store the content of a
6567 ** single database page. The pExtra element of sqlite3_pcache_page will be
6568 ** a pointer to the szExtra bytes of extra storage that SQLite has requested
6569 ** for each entry in the page cache.
6571 ** The page to be fetched is determined by the key. ^The minimum key value
6572 ** is 1. After it has been retrieved using xFetch, the page is considered
6575 ** If the requested page is already in the page cache, then the page cache
6576 ** implementation must return a pointer to the page buffer with its content
6577 ** intact. If the requested page is not already in the cache, then the
6578 ** cache implementation should use the value of the createFlag
6579 ** parameter to help it determined what action to take:
6581 ** <table border=1 width=85% align=center>
6582 ** <tr><th> createFlag <th> Behavior when page is not already in cache
6583 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
6584 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
6585 ** Otherwise return NULL.
6586 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
6587 ** NULL if allocating a new page is effectively impossible.
6590 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
6591 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
6592 ** failed.)^ In between the to xFetch() calls, SQLite may
6593 ** attempt to unpin one or more cache pages by spilling the content of
6594 ** pinned pages to disk and synching the operating system disk cache.
6596 ** [[the xUnpin() page cache method]]
6597 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
6598 ** as its second argument. If the third parameter, discard, is non-zero,
6599 ** then the page must be evicted from the cache.
6600 ** ^If the discard parameter is
6601 ** zero, then the page may be discarded or retained at the discretion of
6602 ** page cache implementation. ^The page cache implementation
6603 ** may choose to evict unpinned pages at any time.
6605 ** The cache must not perform any reference counting. A single
6606 ** call to xUnpin() unpins the page regardless of the number of prior calls
6609 ** [[the xRekey() page cache methods]]
6610 ** The xRekey() method is used to change the key value associated with the
6611 ** page passed as the second argument. If the cache
6612 ** previously contains an entry associated with newKey, it must be
6613 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
6616 ** When SQLite calls the xTruncate() method, the cache must discard all
6617 ** existing cache entries with page numbers (keys) greater than or equal
6618 ** to the value of the iLimit parameter passed to xTruncate(). If any
6619 ** of these pages are pinned, they are implicitly unpinned, meaning that
6620 ** they can be safely discarded.
6622 ** [[the xDestroy() page cache method]]
6623 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
6624 ** All resources associated with the specified cache should be freed. ^After
6625 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
6626 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
6629 ** [[the xShrink() page cache method]]
6630 ** ^SQLite invokes the xShrink() method when it wants the page cache to
6631 ** free up as much of heap memory as possible. The page cache implementation
6632 ** is not obligated to free any memory, but well-behaved implementations should
6635 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2
;
6636 struct sqlite3_pcache_methods2
{
6639 int (*xInit
)(void*);
6640 void (*xShutdown
)(void*);
6641 sqlite3_pcache
*(*xCreate
)(int szPage
, int szExtra
, int bPurgeable
);
6642 void (*xCachesize
)(sqlite3_pcache
*, int nCachesize
);
6643 int (*xPagecount
)(sqlite3_pcache
*);
6644 sqlite3_pcache_page
*(*xFetch
)(sqlite3_pcache
*, unsigned key
, int createFlag
);
6645 void (*xUnpin
)(sqlite3_pcache
*, sqlite3_pcache_page
*, int discard
);
6646 void (*xRekey
)(sqlite3_pcache
*, sqlite3_pcache_page
*,
6647 unsigned oldKey
, unsigned newKey
);
6648 void (*xTruncate
)(sqlite3_pcache
*, unsigned iLimit
);
6649 void (*xDestroy
)(sqlite3_pcache
*);
6650 void (*xShrink
)(sqlite3_pcache
*);
6654 ** This is the obsolete pcache_methods object that has now been replaced
6655 ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
6656 ** retained in the header file for backwards compatibility only.
6658 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods
;
6659 struct sqlite3_pcache_methods
{
6661 int (*xInit
)(void*);
6662 void (*xShutdown
)(void*);
6663 sqlite3_pcache
*(*xCreate
)(int szPage
, int bPurgeable
);
6664 void (*xCachesize
)(sqlite3_pcache
*, int nCachesize
);
6665 int (*xPagecount
)(sqlite3_pcache
*);
6666 void *(*xFetch
)(sqlite3_pcache
*, unsigned key
, int createFlag
);
6667 void (*xUnpin
)(sqlite3_pcache
*, void*, int discard
);
6668 void (*xRekey
)(sqlite3_pcache
*, void*, unsigned oldKey
, unsigned newKey
);
6669 void (*xTruncate
)(sqlite3_pcache
*, unsigned iLimit
);
6670 void (*xDestroy
)(sqlite3_pcache
*);
6675 ** CAPI3REF: Online Backup Object
6677 ** The sqlite3_backup object records state information about an ongoing
6678 ** online backup operation. ^The sqlite3_backup object is created by
6679 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
6680 ** [sqlite3_backup_finish()].
6682 ** See Also: [Using the SQLite Online Backup API]
6684 typedef struct sqlite3_backup sqlite3_backup
;
6687 ** CAPI3REF: Online Backup API.
6689 ** The backup API copies the content of one database into another.
6690 ** It is useful either for creating backups of databases or
6691 ** for copying in-memory databases to or from persistent files.
6693 ** See Also: [Using the SQLite Online Backup API]
6695 ** ^SQLite holds a write transaction open on the destination database file
6696 ** for the duration of the backup operation.
6697 ** ^The source database is read-locked only while it is being read;
6698 ** it is not locked continuously for the entire backup operation.
6699 ** ^Thus, the backup may be performed on a live source database without
6700 ** preventing other database connections from
6701 ** reading or writing to the source database while the backup is underway.
6703 ** ^(To perform a backup operation:
6705 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
6707 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
6708 ** the data between the two databases, and finally
6709 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
6710 ** associated with the backup operation.
6712 ** There should be exactly one call to sqlite3_backup_finish() for each
6713 ** successful call to sqlite3_backup_init().
6715 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
6717 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
6718 ** [database connection] associated with the destination database
6719 ** and the database name, respectively.
6720 ** ^The database name is "main" for the main database, "temp" for the
6721 ** temporary database, or the name specified after the AS keyword in
6722 ** an [ATTACH] statement for an attached database.
6723 ** ^The S and M arguments passed to
6724 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
6725 ** and database name of the source database, respectively.
6726 ** ^The source and destination [database connections] (parameters S and D)
6727 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
6730 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
6731 ** returned and an error code and error message are stored in the
6732 ** destination [database connection] D.
6733 ** ^The error code and message for the failed call to sqlite3_backup_init()
6734 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
6735 ** [sqlite3_errmsg16()] functions.
6736 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
6737 ** [sqlite3_backup] object.
6738 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
6739 ** sqlite3_backup_finish() functions to perform the specified backup
6742 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
6744 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
6745 ** the source and destination databases specified by [sqlite3_backup] object B.
6746 ** ^If N is negative, all remaining source pages are copied.
6747 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
6748 ** are still more pages to be copied, then the function returns [SQLITE_OK].
6749 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
6750 ** from source to destination, then it returns [SQLITE_DONE].
6751 ** ^If an error occurs while running sqlite3_backup_step(B,N),
6752 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
6753 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
6754 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
6755 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
6757 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
6759 ** <li> the destination database was opened read-only, or
6760 ** <li> the destination database is using write-ahead-log journaling
6761 ** and the destination and source page sizes differ, or
6762 ** <li> the destination database is an in-memory database and the
6763 ** destination and source page sizes differ.
6766 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
6767 ** the [sqlite3_busy_handler | busy-handler function]
6768 ** is invoked (if one is specified). ^If the
6769 ** busy-handler returns non-zero before the lock is available, then
6770 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
6771 ** sqlite3_backup_step() can be retried later. ^If the source
6772 ** [database connection]
6773 ** is being used to write to the source database when sqlite3_backup_step()
6774 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
6775 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
6776 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
6777 ** [SQLITE_READONLY] is returned, then
6778 ** there is no point in retrying the call to sqlite3_backup_step(). These
6779 ** errors are considered fatal.)^ The application must accept
6780 ** that the backup operation has failed and pass the backup operation handle
6781 ** to the sqlite3_backup_finish() to release associated resources.
6783 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
6784 ** on the destination file. ^The exclusive lock is not released until either
6785 ** sqlite3_backup_finish() is called or the backup operation is complete
6786 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
6787 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
6788 ** lasts for the duration of the sqlite3_backup_step() call.
6789 ** ^Because the source database is not locked between calls to
6790 ** sqlite3_backup_step(), the source database may be modified mid-way
6791 ** through the backup process. ^If the source database is modified by an
6792 ** external process or via a database connection other than the one being
6793 ** used by the backup operation, then the backup will be automatically
6794 ** restarted by the next call to sqlite3_backup_step(). ^If the source
6795 ** database is modified by the using the same database connection as is used
6796 ** by the backup operation, then the backup database is automatically
6797 ** updated at the same time.
6799 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
6801 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
6802 ** application wishes to abandon the backup operation, the application
6803 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
6804 ** ^The sqlite3_backup_finish() interfaces releases all
6805 ** resources associated with the [sqlite3_backup] object.
6806 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
6807 ** active write-transaction on the destination database is rolled back.
6808 ** The [sqlite3_backup] object is invalid
6809 ** and may not be used following a call to sqlite3_backup_finish().
6811 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
6812 ** sqlite3_backup_step() errors occurred, regardless or whether or not
6813 ** sqlite3_backup_step() completed.
6814 ** ^If an out-of-memory condition or IO error occurred during any prior
6815 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
6816 ** sqlite3_backup_finish() returns the corresponding [error code].
6818 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
6819 ** is not a permanent error and does not affect the return value of
6820 ** sqlite3_backup_finish().
6822 ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]
6823 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
6825 ** ^Each call to sqlite3_backup_step() sets two values inside
6826 ** the [sqlite3_backup] object: the number of pages still to be backed
6827 ** up and the total number of pages in the source database file.
6828 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
6829 ** retrieve these two values, respectively.
6831 ** ^The values returned by these functions are only updated by
6832 ** sqlite3_backup_step(). ^If the source database is modified during a backup
6833 ** operation, then the values are not updated to account for any extra
6834 ** pages that need to be updated or the size of the source database file
6837 ** <b>Concurrent Usage of Database Handles</b>
6839 ** ^The source [database connection] may be used by the application for other
6840 ** purposes while a backup operation is underway or being initialized.
6841 ** ^If SQLite is compiled and configured to support threadsafe database
6842 ** connections, then the source database connection may be used concurrently
6843 ** from within other threads.
6845 ** However, the application must guarantee that the destination
6846 ** [database connection] is not passed to any other API (by any thread) after
6847 ** sqlite3_backup_init() is called and before the corresponding call to
6848 ** sqlite3_backup_finish(). SQLite does not currently check to see
6849 ** if the application incorrectly accesses the destination [database connection]
6850 ** and so no error code is reported, but the operations may malfunction
6851 ** nevertheless. Use of the destination database connection while a
6852 ** backup is in progress might also also cause a mutex deadlock.
6854 ** If running in [shared cache mode], the application must
6855 ** guarantee that the shared cache used by the destination database
6856 ** is not accessed while the backup is running. In practice this means
6857 ** that the application must guarantee that the disk file being
6858 ** backed up to is not accessed by any connection within the process,
6859 ** not just the specific connection that was passed to sqlite3_backup_init().
6861 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
6862 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
6863 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
6864 ** APIs are not strictly speaking threadsafe. If they are invoked at the
6865 ** same time as another thread is invoking sqlite3_backup_step() it is
6866 ** possible that they return invalid values.
6868 SQLITE_API sqlite3_backup
*sqlite3_backup_init(
6869 sqlite3
*pDest
, /* Destination database handle */
6870 const char *zDestName
, /* Destination database name */
6871 sqlite3
*pSource
, /* Source database handle */
6872 const char *zSourceName
/* Source database name */
6874 SQLITE_API
int sqlite3_backup_step(sqlite3_backup
*p
, int nPage
);
6875 SQLITE_API
int sqlite3_backup_finish(sqlite3_backup
*p
);
6876 SQLITE_API
int sqlite3_backup_remaining(sqlite3_backup
*p
);
6877 SQLITE_API
int sqlite3_backup_pagecount(sqlite3_backup
*p
);
6880 ** CAPI3REF: Unlock Notification
6882 ** ^When running in shared-cache mode, a database operation may fail with
6883 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
6884 ** individual tables within the shared-cache cannot be obtained. See
6885 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
6886 ** ^This API may be used to register a callback that SQLite will invoke
6887 ** when the connection currently holding the required lock relinquishes it.
6888 ** ^This API is only available if the library was compiled with the
6889 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
6891 ** See Also: [Using the SQLite Unlock Notification Feature].
6893 ** ^Shared-cache locks are released when a database connection concludes
6894 ** its current transaction, either by committing it or rolling it back.
6896 ** ^When a connection (known as the blocked connection) fails to obtain a
6897 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
6898 ** identity of the database connection (the blocking connection) that
6899 ** has locked the required resource is stored internally. ^After an
6900 ** application receives an SQLITE_LOCKED error, it may call the
6901 ** sqlite3_unlock_notify() method with the blocked connection handle as
6902 ** the first argument to register for a callback that will be invoked
6903 ** when the blocking connections current transaction is concluded. ^The
6904 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
6905 ** call that concludes the blocking connections transaction.
6907 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
6908 ** there is a chance that the blocking connection will have already
6909 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
6910 ** If this happens, then the specified callback is invoked immediately,
6911 ** from within the call to sqlite3_unlock_notify().)^
6913 ** ^If the blocked connection is attempting to obtain a write-lock on a
6914 ** shared-cache table, and more than one other connection currently holds
6915 ** a read-lock on the same table, then SQLite arbitrarily selects one of
6916 ** the other connections to use as the blocking connection.
6918 ** ^(There may be at most one unlock-notify callback registered by a
6919 ** blocked connection. If sqlite3_unlock_notify() is called when the
6920 ** blocked connection already has a registered unlock-notify callback,
6921 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
6922 ** called with a NULL pointer as its second argument, then any existing
6923 ** unlock-notify callback is canceled. ^The blocked connections
6924 ** unlock-notify callback may also be canceled by closing the blocked
6925 ** connection using [sqlite3_close()].
6927 ** The unlock-notify callback is not reentrant. If an application invokes
6928 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
6929 ** crash or deadlock may be the result.
6931 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
6932 ** returns SQLITE_OK.
6934 ** <b>Callback Invocation Details</b>
6936 ** When an unlock-notify callback is registered, the application provides a
6937 ** single void* pointer that is passed to the callback when it is invoked.
6938 ** However, the signature of the callback function allows SQLite to pass
6939 ** it an array of void* context pointers. The first argument passed to
6940 ** an unlock-notify callback is a pointer to an array of void* pointers,
6941 ** and the second is the number of entries in the array.
6943 ** When a blocking connections transaction is concluded, there may be
6944 ** more than one blocked connection that has registered for an unlock-notify
6945 ** callback. ^If two or more such blocked connections have specified the
6946 ** same callback function, then instead of invoking the callback function
6947 ** multiple times, it is invoked once with the set of void* context pointers
6948 ** specified by the blocked connections bundled together into an array.
6949 ** This gives the application an opportunity to prioritize any actions
6950 ** related to the set of unblocked database connections.
6952 ** <b>Deadlock Detection</b>
6954 ** Assuming that after registering for an unlock-notify callback a
6955 ** database waits for the callback to be issued before taking any further
6956 ** action (a reasonable assumption), then using this API may cause the
6957 ** application to deadlock. For example, if connection X is waiting for
6958 ** connection Y's transaction to be concluded, and similarly connection
6959 ** Y is waiting on connection X's transaction, then neither connection
6960 ** will proceed and the system may remain deadlocked indefinitely.
6962 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
6963 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
6964 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
6965 ** unlock-notify callback is registered. The system is said to be in
6966 ** a deadlocked state if connection A has registered for an unlock-notify
6967 ** callback on the conclusion of connection B's transaction, and connection
6968 ** B has itself registered for an unlock-notify callback when connection
6969 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
6970 ** the system is also considered to be deadlocked if connection B has
6971 ** registered for an unlock-notify callback on the conclusion of connection
6972 ** C's transaction, where connection C is waiting on connection A. ^Any
6973 ** number of levels of indirection are allowed.
6975 ** <b>The "DROP TABLE" Exception</b>
6977 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
6978 ** always appropriate to call sqlite3_unlock_notify(). There is however,
6979 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
6980 ** SQLite checks if there are any currently executing SELECT statements
6981 ** that belong to the same connection. If there are, SQLITE_LOCKED is
6982 ** returned. In this case there is no "blocking connection", so invoking
6983 ** sqlite3_unlock_notify() results in the unlock-notify callback being
6984 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
6985 ** or "DROP INDEX" query, an infinite loop might be the result.
6987 ** One way around this problem is to check the extended error code returned
6988 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
6989 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
6990 ** the special "DROP TABLE/INDEX" case, the extended error code is just
6993 SQLITE_API
int sqlite3_unlock_notify(
6994 sqlite3
*pBlocked
, /* Waiting connection */
6995 void (*xNotify
)(void **apArg
, int nArg
), /* Callback function to invoke */
6996 void *pNotifyArg
/* Argument to pass to xNotify */
7001 ** CAPI3REF: String Comparison
7003 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
7004 ** and extensions to compare the contents of two buffers containing UTF-8
7005 ** strings in a case-independent fashion, using the same definition of "case
7006 ** independence" that SQLite uses internally when comparing identifiers.
7008 SQLITE_API
int sqlite3_stricmp(const char *, const char *);
7009 SQLITE_API
int sqlite3_strnicmp(const char *, const char *, int);
7012 ** CAPI3REF: String Globbing
7014 ** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches
7015 ** the glob pattern P, and it returns non-zero if string X does not match
7016 ** the glob pattern P. ^The definition of glob pattern matching used in
7017 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
7018 ** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case
7021 ** Note that this routine returns zero on a match and non-zero if the strings
7022 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
7024 SQLITE_API
int sqlite3_strglob(const char *zGlob
, const char *zStr
);
7027 ** CAPI3REF: Error Logging Interface
7029 ** ^The [sqlite3_log()] interface writes a message into the [error log]
7030 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
7031 ** ^If logging is enabled, the zFormat string and subsequent arguments are
7032 ** used with [sqlite3_snprintf()] to generate the final output string.
7034 ** The sqlite3_log() interface is intended for use by extensions such as
7035 ** virtual tables, collating functions, and SQL functions. While there is
7036 ** nothing to prevent an application from calling sqlite3_log(), doing so
7037 ** is considered bad form.
7039 ** The zFormat string must not be NULL.
7041 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
7042 ** will not use dynamically allocated memory. The log message is stored in
7043 ** a fixed-length buffer on the stack. If the log message is longer than
7044 ** a few hundred characters, it will be truncated to the length of the
7047 SQLITE_API
void sqlite3_log(int iErrCode
, const char *zFormat
, ...);
7050 ** CAPI3REF: Write-Ahead Log Commit Hook
7052 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
7053 ** will be invoked each time a database connection commits data to a
7054 ** [write-ahead log] (i.e. whenever a transaction is committed in
7055 ** [journal_mode | journal_mode=WAL mode]).
7057 ** ^The callback is invoked by SQLite after the commit has taken place and
7058 ** the associated write-lock on the database released, so the implementation
7059 ** may read, write or [checkpoint] the database as required.
7061 ** ^The first parameter passed to the callback function when it is invoked
7062 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
7063 ** registering the callback. ^The second is a copy of the database handle.
7064 ** ^The third parameter is the name of the database that was written to -
7065 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
7066 ** is the number of pages currently in the write-ahead log file,
7067 ** including those that were just committed.
7069 ** The callback function should normally return [SQLITE_OK]. ^If an error
7070 ** code is returned, that error will propagate back up through the
7071 ** SQLite code base to cause the statement that provoked the callback
7072 ** to report an error, though the commit will have still occurred. If the
7073 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
7074 ** that does not correspond to any valid SQLite error code, the results
7077 ** A single database handle may have at most a single write-ahead log callback
7078 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
7079 ** previously registered write-ahead log callback. ^Note that the
7080 ** [sqlite3_wal_autocheckpoint()] interface and the
7081 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
7082 ** those overwrite any prior [sqlite3_wal_hook()] settings.
7084 SQLITE_API
void *sqlite3_wal_hook(
7086 int(*)(void *,sqlite3
*,const char*,int),
7091 ** CAPI3REF: Configure an auto-checkpoint
7093 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
7094 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
7095 ** to automatically [checkpoint]
7096 ** after committing a transaction if there are N or
7097 ** more frames in the [write-ahead log] file. ^Passing zero or
7098 ** a negative value as the nFrame parameter disables automatic
7099 ** checkpoints entirely.
7101 ** ^The callback registered by this function replaces any existing callback
7102 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
7103 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
7104 ** configured by this function.
7106 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
7109 ** ^Every new [database connection] defaults to having the auto-checkpoint
7110 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
7111 ** pages. The use of this interface
7112 ** is only necessary if the default setting is found to be suboptimal
7113 ** for a particular application.
7115 SQLITE_API
int sqlite3_wal_autocheckpoint(sqlite3
*db
, int N
);
7118 ** CAPI3REF: Checkpoint a database
7120 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
7121 ** on [database connection] D to be [checkpointed]. ^If X is NULL or an
7122 ** empty string, then a checkpoint is run on all databases of
7123 ** connection D. ^If the database connection D is not in
7124 ** [WAL | write-ahead log mode] then this interface is a harmless no-op.
7126 ** ^The [wal_checkpoint pragma] can be used to invoke this interface
7127 ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the
7128 ** [wal_autocheckpoint pragma] can be used to cause this interface to be
7129 ** run whenever the WAL reaches a certain size threshold.
7131 ** See also: [sqlite3_wal_checkpoint_v2()]
7133 SQLITE_API
int sqlite3_wal_checkpoint(sqlite3
*db
, const char *zDb
);
7136 ** CAPI3REF: Checkpoint a database
7138 ** Run a checkpoint operation on WAL database zDb attached to database
7139 ** handle db. The specific operation is determined by the value of the
7143 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
7144 ** Checkpoint as many frames as possible without waiting for any database
7145 ** readers or writers to finish. Sync the db file if all frames in the log
7146 ** are checkpointed. This mode is the same as calling
7147 ** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked.
7149 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
7150 ** This mode blocks (calls the busy-handler callback) until there is no
7151 ** database writer and all readers are reading from the most recent database
7152 ** snapshot. It then checkpoints all frames in the log file and syncs the
7153 ** database file. This call blocks database writers while it is running,
7154 ** but not database readers.
7156 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
7157 ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after
7158 ** checkpointing the log file it blocks (calls the busy-handler callback)
7159 ** until all readers are reading from the database file only. This ensures
7160 ** that the next client to write to the database file restarts the log file
7161 ** from the beginning. This call blocks database writers while it is running,
7162 ** but not database readers.
7165 ** If pnLog is not NULL, then *pnLog is set to the total number of frames in
7166 ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
7167 ** the total number of checkpointed frames (including any that were already
7168 ** checkpointed when this function is called). *pnLog and *pnCkpt may be
7169 ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
7170 ** If no values are available because of an error, they are both set to -1
7171 ** before returning to communicate this to the caller.
7173 ** All calls obtain an exclusive "checkpoint" lock on the database file. If
7174 ** any other process is running a checkpoint operation at the same time, the
7175 ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a
7176 ** busy-handler configured, it will not be invoked in this case.
7178 ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive
7179 ** "writer" lock on the database file. If the writer lock cannot be obtained
7180 ** immediately, and a busy-handler is configured, it is invoked and the writer
7181 ** lock retried until either the busy-handler returns 0 or the lock is
7182 ** successfully obtained. The busy-handler is also invoked while waiting for
7183 ** database readers as described above. If the busy-handler returns 0 before
7184 ** the writer lock is obtained or while waiting for database readers, the
7185 ** checkpoint operation proceeds from that point in the same way as
7186 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
7187 ** without blocking any further. SQLITE_BUSY is returned in this case.
7189 ** If parameter zDb is NULL or points to a zero length string, then the
7190 ** specified operation is attempted on all WAL databases. In this case the
7191 ** values written to output parameters *pnLog and *pnCkpt are undefined. If
7192 ** an SQLITE_BUSY error is encountered when processing one or more of the
7193 ** attached WAL databases, the operation is still attempted on any remaining
7194 ** attached databases and SQLITE_BUSY is returned to the caller. If any other
7195 ** error occurs while processing an attached database, processing is abandoned
7196 ** and the error code returned to the caller immediately. If no error
7197 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
7198 ** databases, SQLITE_OK is returned.
7200 ** If database zDb is the name of an attached database that is not in WAL
7201 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
7202 ** zDb is not NULL (or a zero length string) and is not the name of any
7203 ** attached database, SQLITE_ERROR is returned to the caller.
7205 SQLITE_API
int sqlite3_wal_checkpoint_v2(
7206 sqlite3
*db
, /* Database handle */
7207 const char *zDb
, /* Name of attached database (or NULL) */
7208 int eMode
, /* SQLITE_CHECKPOINT_* value */
7209 int *pnLog
, /* OUT: Size of WAL log in frames */
7210 int *pnCkpt
/* OUT: Total number of frames checkpointed */
7214 ** CAPI3REF: Checkpoint operation parameters
7216 ** These constants can be used as the 3rd parameter to
7217 ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()]
7218 ** documentation for additional information about the meaning and use of
7219 ** each of these values.
7221 #define SQLITE_CHECKPOINT_PASSIVE 0
7222 #define SQLITE_CHECKPOINT_FULL 1
7223 #define SQLITE_CHECKPOINT_RESTART 2
7226 ** CAPI3REF: Virtual Table Interface Configuration
7228 ** This function may be called by either the [xConnect] or [xCreate] method
7229 ** of a [virtual table] implementation to configure
7230 ** various facets of the virtual table interface.
7232 ** If this interface is invoked outside the context of an xConnect or
7233 ** xCreate virtual table method then the behavior is undefined.
7235 ** At present, there is only one option that may be configured using
7236 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options
7237 ** may be added in the future.
7239 SQLITE_API
int sqlite3_vtab_config(sqlite3
*, int op
, ...);
7242 ** CAPI3REF: Virtual Table Configuration Options
7244 ** These macros define the various options to the
7245 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
7246 ** can use to customize and optimize their behavior.
7249 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
7250 ** <dd>Calls of the form
7251 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
7252 ** where X is an integer. If X is zero, then the [virtual table] whose
7253 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
7254 ** support constraints. In this configuration (which is the default) if
7255 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
7256 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
7257 ** specified as part of the users SQL statement, regardless of the actual
7258 ** ON CONFLICT mode specified.
7260 ** If X is non-zero, then the virtual table implementation guarantees
7261 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
7262 ** any modifications to internal or persistent data structures have been made.
7263 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
7264 ** is able to roll back a statement or database transaction, and abandon
7265 ** or continue processing the current SQL statement as appropriate.
7266 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
7267 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
7270 ** Virtual table implementations that are required to handle OR REPLACE
7271 ** must do so within the [xUpdate] method. If a call to the
7272 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
7273 ** CONFLICT policy is REPLACE, the virtual table implementation should
7274 ** silently replace the appropriate rows within the xUpdate callback and
7275 ** return SQLITE_OK. Or, if this is not possible, it may return
7276 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
7277 ** constraint handling.
7280 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
7283 ** CAPI3REF: Determine The Virtual Table Conflict Policy
7285 ** This function may only be called from within a call to the [xUpdate] method
7286 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
7287 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
7288 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
7289 ** of the SQL statement that triggered the call to the [xUpdate] method of the
7292 SQLITE_API
int sqlite3_vtab_on_conflict(sqlite3
*);
7295 ** CAPI3REF: Conflict resolution modes
7297 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
7298 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
7299 ** is for the SQL statement being evaluated.
7301 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
7302 ** return value from the [sqlite3_set_authorizer()] callback and that
7303 ** [SQLITE_ABORT] is also a [result code].
7305 #define SQLITE_ROLLBACK 1
7306 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
7307 #define SQLITE_FAIL 3
7308 /* #define SQLITE_ABORT 4 // Also an error code */
7309 #define SQLITE_REPLACE 5
7314 ** Undo the hack that converts floating point types to integer for
7315 ** builds on processors without floating point support.
7317 #ifdef SQLITE_OMIT_FLOATING_POINT
7322 } /* End of the 'extern "C"' block */
7324 #endif /* _SQLITE3_H_ */
7329 ** The author disclaims copyright to this source code. In place of
7330 ** a legal notice, here is a blessing:
7332 ** May you do good and not evil.
7333 ** May you find forgiveness for yourself and forgive others.
7334 ** May you share freely, never taking more than you give.
7336 *************************************************************************
7339 #ifndef _SQLITE3RTREE_H_
7340 #define _SQLITE3RTREE_H_
7347 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry
;
7350 ** Register a geometry callback named zGeom that can be used as part of an
7351 ** R-Tree geometry query as follows:
7353 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
7355 SQLITE_API
int sqlite3_rtree_geometry_callback(
7358 #ifdef SQLITE_RTREE_INT_ONLY
7359 int (*xGeom
)(sqlite3_rtree_geometry
*, int n
, sqlite3_int64
*a
, int *pRes
),
7361 int (*xGeom
)(sqlite3_rtree_geometry
*, int n
, double *a
, int *pRes
),
7368 ** A pointer to a structure of the following type is passed as the first
7369 ** argument to callbacks registered using rtree_geometry_callback().
7371 struct sqlite3_rtree_geometry
{
7372 void *pContext
; /* Copy of pContext passed to s_r_g_c() */
7373 int nParam
; /* Size of array aParam[] */
7374 double *aParam
; /* Parameters passed to SQL geom function */
7375 void *pUser
; /* Callback implementation user data */
7376 void (*xDelUser
)(void *); /* Called by SQLite to clean up pUser */
7381 } /* end of the 'extern "C"' block */
7384 #endif /* ifndef _SQLITE3RTREE_H_ */