Ensure that sqlite3AuthRead() is only call for TK_COLUMN and TK_TRIGGER
[sqlite.git] / src / sqlite.h.in
blob3d2effa5b78127f1291f2ba106de1c59ecdf17e1
1 /*
2 ** 2001-09-15
3 **
4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
6 **
7 ** May you do good and not evil.
8 ** May you find forgiveness for yourself and forgive others.
9 ** May you share freely, never taking more than you give.
11 *************************************************************************
12 ** This header file defines the interface that the SQLite library
13 ** presents to client programs. If a C-function, structure, datatype,
14 ** or constant definition does not appear in this file, then it is
15 ** not a published API of SQLite, is subject to change without
16 ** notice, and should not be referenced by programs that use SQLite.
18 ** Some of the definitions that are in this file are marked as
19 ** "experimental". Experimental interfaces are normally new
20 ** features recently added to SQLite. We do not anticipate changes
21 ** to experimental interfaces but reserve the right to make minor changes
22 ** if experience from use "in the wild" suggest such changes are prudent.
24 ** The official C-language API documentation for SQLite is derived
25 ** from comments in this file. This file is the authoritative source
26 ** on how SQLite interfaces are supposed to operate.
28 ** The name of this file under configuration management is "sqlite.h.in".
29 ** The makefile makes some minor changes to this file (such as inserting
30 ** the version number) and changes its name to "sqlite3.h" as
31 ** part of the build process.
33 #ifndef SQLITE3_H
34 #define SQLITE3_H
35 #include <stdarg.h> /* Needed for the definition of va_list */
38 ** Make sure we can call this stuff from C++.
40 #ifdef __cplusplus
41 extern "C" {
42 #endif
46 ** Provide the ability to override linkage features of the interface.
48 #ifndef SQLITE_EXTERN
49 # define SQLITE_EXTERN extern
50 #endif
51 #ifndef SQLITE_API
52 # define SQLITE_API
53 #endif
54 #ifndef SQLITE_CDECL
55 # define SQLITE_CDECL
56 #endif
57 #ifndef SQLITE_APICALL
58 # define SQLITE_APICALL
59 #endif
60 #ifndef SQLITE_STDCALL
61 # define SQLITE_STDCALL SQLITE_APICALL
62 #endif
63 #ifndef SQLITE_CALLBACK
64 # define SQLITE_CALLBACK
65 #endif
66 #ifndef SQLITE_SYSAPI
67 # define SQLITE_SYSAPI
68 #endif
71 ** These no-op macros are used in front of interfaces to mark those
72 ** interfaces as either deprecated or experimental. New applications
73 ** should not use deprecated interfaces - they are supported for backwards
74 ** compatibility only. Application writers should be aware that
75 ** experimental interfaces are subject to change in point releases.
77 ** These macros used to resolve to various kinds of compiler magic that
78 ** would generate warning messages when they were used. But that
79 ** compiler magic ended up generating such a flurry of bug reports
80 ** that we have taken it all out and gone back to using simple
81 ** noop macros.
83 #define SQLITE_DEPRECATED
84 #define SQLITE_EXPERIMENTAL
87 ** Ensure these symbols were not defined by some previous header file.
89 #ifdef SQLITE_VERSION
90 # undef SQLITE_VERSION
91 #endif
92 #ifdef SQLITE_VERSION_NUMBER
93 # undef SQLITE_VERSION_NUMBER
94 #endif
97 ** CAPI3REF: Compile-Time Library Version Numbers
99 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
100 ** evaluates to a string literal that is the SQLite version in the
101 ** format "X.Y.Z" where X is the major version number (always 3 for
102 ** SQLite3) and Y is the minor version number and Z is the release number.)^
103 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
104 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
105 ** numbers used in [SQLITE_VERSION].)^
106 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
107 ** be larger than the release from which it is derived. Either Y will
108 ** be held constant and Z will be incremented or else Y will be incremented
109 ** and Z will be reset to zero.
111 ** Since [version 3.6.18] ([dateof:3.6.18]),
112 ** SQLite source code has been stored in the
113 ** <a href="http://www.fossil-scm.org/">Fossil configuration management
114 ** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to
115 ** a string which identifies a particular check-in of SQLite
116 ** within its configuration management system. ^The SQLITE_SOURCE_ID
117 ** string contains the date and time of the check-in (UTC) and a SHA1
118 ** or SHA3-256 hash of the entire source tree. If the source code has
119 ** been edited in any way since it was last checked in, then the last
120 ** four hexadecimal digits of the hash may be modified.
122 ** See also: [sqlite3_libversion()],
123 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
124 ** [sqlite_version()] and [sqlite_source_id()].
126 #define SQLITE_VERSION "--VERS--"
127 #define SQLITE_VERSION_NUMBER --VERSION-NUMBER--
128 #define SQLITE_SOURCE_ID "--SOURCE-ID--"
131 ** CAPI3REF: Run-Time Library Version Numbers
132 ** KEYWORDS: sqlite3_version sqlite3_sourceid
134 ** These interfaces provide the same information as the [SQLITE_VERSION],
135 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
136 ** but are associated with the library instead of the header file. ^(Cautious
137 ** programmers might include assert() statements in their application to
138 ** verify that values returned by these interfaces match the macros in
139 ** the header, and thus ensure that the application is
140 ** compiled with matching library and header files.
142 ** <blockquote><pre>
143 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
144 ** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
145 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
146 ** </pre></blockquote>)^
148 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
149 ** macro. ^The sqlite3_libversion() function returns a pointer to the
150 ** to the sqlite3_version[] string constant. The sqlite3_libversion()
151 ** function is provided for use in DLLs since DLL users usually do not have
152 ** direct access to string constants within the DLL. ^The
153 ** sqlite3_libversion_number() function returns an integer equal to
154 ** [SQLITE_VERSION_NUMBER]. ^(The sqlite3_sourceid() function returns
155 ** a pointer to a string constant whose value is the same as the
156 ** [SQLITE_SOURCE_ID] C preprocessor macro. Except if SQLite is built
157 ** using an edited copy of [the amalgamation], then the last four characters
158 ** of the hash might be different from [SQLITE_SOURCE_ID].)^
160 ** See also: [sqlite_version()] and [sqlite_source_id()].
162 SQLITE_EXTERN const char sqlite3_version[];
163 const char *sqlite3_libversion(void);
164 const char *sqlite3_sourceid(void);
165 int sqlite3_libversion_number(void);
168 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
170 ** ^The sqlite3_compileoption_used() function returns 0 or 1
171 ** indicating whether the specified option was defined at
172 ** compile time. ^The SQLITE_ prefix may be omitted from the
173 ** option name passed to sqlite3_compileoption_used().
175 ** ^The sqlite3_compileoption_get() function allows iterating
176 ** over the list of options that were defined at compile time by
177 ** returning the N-th compile time option string. ^If N is out of range,
178 ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
179 ** prefix is omitted from any strings returned by
180 ** sqlite3_compileoption_get().
182 ** ^Support for the diagnostic functions sqlite3_compileoption_used()
183 ** and sqlite3_compileoption_get() may be omitted by specifying the
184 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
186 ** See also: SQL functions [sqlite_compileoption_used()] and
187 ** [sqlite_compileoption_get()] and the [compile_options pragma].
189 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
190 int sqlite3_compileoption_used(const char *zOptName);
191 const char *sqlite3_compileoption_get(int N);
192 #endif
195 ** CAPI3REF: Test To See If The Library Is Threadsafe
197 ** ^The sqlite3_threadsafe() function returns zero if and only if
198 ** SQLite was compiled with mutexing code omitted due to the
199 ** [SQLITE_THREADSAFE] compile-time option being set to 0.
201 ** SQLite can be compiled with or without mutexes. When
202 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
203 ** are enabled and SQLite is threadsafe. When the
204 ** [SQLITE_THREADSAFE] macro is 0,
205 ** the mutexes are omitted. Without the mutexes, it is not safe
206 ** to use SQLite concurrently from more than one thread.
208 ** Enabling mutexes incurs a measurable performance penalty.
209 ** So if speed is of utmost importance, it makes sense to disable
210 ** the mutexes. But for maximum safety, mutexes should be enabled.
211 ** ^The default behavior is for mutexes to be enabled.
213 ** This interface can be used by an application to make sure that the
214 ** version of SQLite that it is linking against was compiled with
215 ** the desired setting of the [SQLITE_THREADSAFE] macro.
217 ** This interface only reports on the compile-time mutex setting
218 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
219 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
220 ** can be fully or partially disabled using a call to [sqlite3_config()]
221 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
222 ** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the
223 ** sqlite3_threadsafe() function shows only the compile-time setting of
224 ** thread safety, not any run-time changes to that setting made by
225 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
226 ** is unchanged by calls to sqlite3_config().)^
228 ** See the [threading mode] documentation for additional information.
230 int sqlite3_threadsafe(void);
233 ** CAPI3REF: Database Connection Handle
234 ** KEYWORDS: {database connection} {database connections}
236 ** Each open SQLite database is represented by a pointer to an instance of
237 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3
238 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
239 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
240 ** and [sqlite3_close_v2()] are its destructors. There are many other
241 ** interfaces (such as
242 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
243 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
244 ** sqlite3 object.
246 typedef struct sqlite3 sqlite3;
249 ** CAPI3REF: 64-Bit Integer Types
250 ** KEYWORDS: sqlite_int64 sqlite_uint64
252 ** Because there is no cross-platform way to specify 64-bit integer types
253 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
255 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
256 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
257 ** compatibility only.
259 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
260 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
261 ** sqlite3_uint64 and sqlite_uint64 types can store integer values
262 ** between 0 and +18446744073709551615 inclusive.
264 #ifdef SQLITE_INT64_TYPE
265 typedef SQLITE_INT64_TYPE sqlite_int64;
266 # ifdef SQLITE_UINT64_TYPE
267 typedef SQLITE_UINT64_TYPE sqlite_uint64;
268 # else
269 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
270 # endif
271 #elif defined(_MSC_VER) || defined(__BORLANDC__)
272 typedef __int64 sqlite_int64;
273 typedef unsigned __int64 sqlite_uint64;
274 #else
275 typedef long long int sqlite_int64;
276 typedef unsigned long long int sqlite_uint64;
277 #endif
278 typedef sqlite_int64 sqlite3_int64;
279 typedef sqlite_uint64 sqlite3_uint64;
282 ** If compiling for a processor that lacks floating point support,
283 ** substitute integer for floating-point.
285 #ifdef SQLITE_OMIT_FLOATING_POINT
286 # define double sqlite3_int64
287 #endif
290 ** CAPI3REF: Closing A Database Connection
291 ** DESTRUCTOR: sqlite3
293 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
294 ** for the [sqlite3] object.
295 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
296 ** the [sqlite3] object is successfully destroyed and all associated
297 ** resources are deallocated.
299 ** ^If the database connection is associated with unfinalized prepared
300 ** statements or unfinished sqlite3_backup objects then sqlite3_close()
301 ** will leave the database connection open and return [SQLITE_BUSY].
302 ** ^If sqlite3_close_v2() is called with unfinalized prepared statements
303 ** and/or unfinished sqlite3_backups, then the database connection becomes
304 ** an unusable "zombie" which will automatically be deallocated when the
305 ** last prepared statement is finalized or the last sqlite3_backup is
306 ** finished. The sqlite3_close_v2() interface is intended for use with
307 ** host languages that are garbage collected, and where the order in which
308 ** destructors are called is arbitrary.
310 ** Applications should [sqlite3_finalize | finalize] all [prepared statements],
311 ** [sqlite3_blob_close | close] all [BLOB handles], and
312 ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
313 ** with the [sqlite3] object prior to attempting to close the object. ^If
314 ** sqlite3_close_v2() is called on a [database connection] that still has
315 ** outstanding [prepared statements], [BLOB handles], and/or
316 ** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
317 ** of resources is deferred until all [prepared statements], [BLOB handles],
318 ** and [sqlite3_backup] objects are also destroyed.
320 ** ^If an [sqlite3] object is destroyed while a transaction is open,
321 ** the transaction is automatically rolled back.
323 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
324 ** must be either a NULL
325 ** pointer or an [sqlite3] object pointer obtained
326 ** from [sqlite3_open()], [sqlite3_open16()], or
327 ** [sqlite3_open_v2()], and not previously closed.
328 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
329 ** argument is a harmless no-op.
331 int sqlite3_close(sqlite3*);
332 int sqlite3_close_v2(sqlite3*);
335 ** The type for a callback function.
336 ** This is legacy and deprecated. It is included for historical
337 ** compatibility and is not documented.
339 typedef int (*sqlite3_callback)(void*,int,char**, char**);
342 ** CAPI3REF: One-Step Query Execution Interface
343 ** METHOD: sqlite3
345 ** The sqlite3_exec() interface is a convenience wrapper around
346 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
347 ** that allows an application to run multiple statements of SQL
348 ** without having to use a lot of C code.
350 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
351 ** semicolon-separate SQL statements passed into its 2nd argument,
352 ** in the context of the [database connection] passed in as its 1st
353 ** argument. ^If the callback function of the 3rd argument to
354 ** sqlite3_exec() is not NULL, then it is invoked for each result row
355 ** coming out of the evaluated SQL statements. ^The 4th argument to
356 ** sqlite3_exec() is relayed through to the 1st argument of each
357 ** callback invocation. ^If the callback pointer to sqlite3_exec()
358 ** is NULL, then no callback is ever invoked and result rows are
359 ** ignored.
361 ** ^If an error occurs while evaluating the SQL statements passed into
362 ** sqlite3_exec(), then execution of the current statement stops and
363 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
364 ** is not NULL then any error message is written into memory obtained
365 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
366 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
367 ** on error message strings returned through the 5th parameter of
368 ** sqlite3_exec() after the error message string is no longer needed.
369 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
370 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
371 ** NULL before returning.
373 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
374 ** routine returns SQLITE_ABORT without invoking the callback again and
375 ** without running any subsequent SQL statements.
377 ** ^The 2nd argument to the sqlite3_exec() callback function is the
378 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
379 ** callback is an array of pointers to strings obtained as if from
380 ** [sqlite3_column_text()], one for each column. ^If an element of a
381 ** result row is NULL then the corresponding string pointer for the
382 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
383 ** sqlite3_exec() callback is an array of pointers to strings where each
384 ** entry represents the name of corresponding result column as obtained
385 ** from [sqlite3_column_name()].
387 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
388 ** to an empty string, or a pointer that contains only whitespace and/or
389 ** SQL comments, then no SQL statements are evaluated and the database
390 ** is not changed.
392 ** Restrictions:
394 ** <ul>
395 ** <li> The application must ensure that the 1st parameter to sqlite3_exec()
396 ** is a valid and open [database connection].
397 ** <li> The application must not close the [database connection] specified by
398 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
399 ** <li> The application must not modify the SQL statement text passed into
400 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
401 ** </ul>
403 int sqlite3_exec(
404 sqlite3*, /* An open database */
405 const char *sql, /* SQL to be evaluated */
406 int (*callback)(void*,int,char**,char**), /* Callback function */
407 void *, /* 1st argument to callback */
408 char **errmsg /* Error msg written here */
412 ** CAPI3REF: Result Codes
413 ** KEYWORDS: {result code definitions}
415 ** Many SQLite functions return an integer result code from the set shown
416 ** here in order to indicate success or failure.
418 ** New error codes may be added in future versions of SQLite.
420 ** See also: [extended result code definitions]
422 #define SQLITE_OK 0 /* Successful result */
423 /* beginning-of-error-codes */
424 #define SQLITE_ERROR 1 /* Generic error */
425 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
426 #define SQLITE_PERM 3 /* Access permission denied */
427 #define SQLITE_ABORT 4 /* Callback routine requested an abort */
428 #define SQLITE_BUSY 5 /* The database file is locked */
429 #define SQLITE_LOCKED 6 /* A table in the database is locked */
430 #define SQLITE_NOMEM 7 /* A malloc() failed */
431 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */
432 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
433 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
434 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */
435 #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
436 #define SQLITE_FULL 13 /* Insertion failed because database is full */
437 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */
438 #define SQLITE_PROTOCOL 15 /* Database lock protocol error */
439 #define SQLITE_EMPTY 16 /* Internal use only */
440 #define SQLITE_SCHEMA 17 /* The database schema changed */
441 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
442 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
443 #define SQLITE_MISMATCH 20 /* Data type mismatch */
444 #define SQLITE_MISUSE 21 /* Library used incorrectly */
445 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
446 #define SQLITE_AUTH 23 /* Authorization denied */
447 #define SQLITE_FORMAT 24 /* Not used */
448 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
449 #define SQLITE_NOTADB 26 /* File opened that is not a database file */
450 #define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */
451 #define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */
452 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
453 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
454 /* end-of-error-codes */
457 ** CAPI3REF: Extended Result Codes
458 ** KEYWORDS: {extended result code definitions}
460 ** In its default configuration, SQLite API routines return one of 30 integer
461 ** [result codes]. However, experience has shown that many of
462 ** these result codes are too coarse-grained. They do not provide as
463 ** much information about problems as programmers might like. In an effort to
464 ** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
465 ** and later) include
466 ** support for additional result codes that provide more detailed information
467 ** about errors. These [extended result codes] are enabled or disabled
468 ** on a per database connection basis using the
469 ** [sqlite3_extended_result_codes()] API. Or, the extended code for
470 ** the most recent error can be obtained using
471 ** [sqlite3_extended_errcode()].
473 #define SQLITE_ERROR_MISSING_COLLSEQ (SQLITE_ERROR | (1<<8))
474 #define SQLITE_ERROR_RETRY (SQLITE_ERROR | (2<<8))
475 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
476 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
477 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
478 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
479 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
480 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
481 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
482 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
483 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
484 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
485 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
486 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
487 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
488 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
489 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
490 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
491 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
492 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
493 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
494 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
495 #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
496 #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
497 #define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
498 #define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
499 #define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8))
500 #define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8))
501 #define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8))
502 #define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8))
503 #define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8))
504 #define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8))
505 #define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8))
506 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
507 #define SQLITE_LOCKED_VTAB (SQLITE_LOCKED | (2<<8))
508 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
509 #define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8))
510 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
511 #define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
512 #define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
513 #define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8))
514 #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
515 #define SQLITE_CORRUPT_SEQUENCE (SQLITE_CORRUPT | (2<<8))
516 #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
517 #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
518 #define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8))
519 #define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8))
520 #define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8))
521 #define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8))
522 #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
523 #define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8))
524 #define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8))
525 #define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8))
526 #define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8))
527 #define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8))
528 #define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8))
529 #define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8))
530 #define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8))
531 #define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8))
532 #define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8))
533 #define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8))
534 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
535 #define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8))
536 #define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8))
537 #define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8))
540 ** CAPI3REF: Flags For File Open Operations
542 ** These bit values are intended for use in the
543 ** 3rd parameter to the [sqlite3_open_v2()] interface and
544 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
546 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
547 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
548 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
549 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
550 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
551 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
552 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
553 #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
554 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
555 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
556 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
557 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
558 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
559 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
560 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
561 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
562 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
563 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
564 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
565 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
567 /* Reserved: 0x00F00000 */
570 ** CAPI3REF: Device Characteristics
572 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
573 ** object returns an integer which is a vector of these
574 ** bit values expressing I/O characteristics of the mass storage
575 ** device that holds the file that the [sqlite3_io_methods]
576 ** refers to.
578 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
579 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
580 ** mean that writes of blocks that are nnn bytes in size and
581 ** are aligned to an address which is an integer multiple of
582 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
583 ** that when data is appended to a file, the data is appended
584 ** first then the size of the file is extended, never the other
585 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
586 ** information is written to disk in the same order as calls
587 ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
588 ** after reboot following a crash or power loss, the only bytes in a
589 ** file that were written at the application level might have changed
590 ** and that adjacent bytes, even bytes within the same sector are
591 ** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
592 ** flag indicates that a file cannot be deleted when open. The
593 ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
594 ** read-only media and cannot be changed even by processes with
595 ** elevated privileges.
597 ** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
598 ** filesystem supports doing multiple write operations atomically when those
599 ** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
600 ** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
602 #define SQLITE_IOCAP_ATOMIC 0x00000001
603 #define SQLITE_IOCAP_ATOMIC512 0x00000002
604 #define SQLITE_IOCAP_ATOMIC1K 0x00000004
605 #define SQLITE_IOCAP_ATOMIC2K 0x00000008
606 #define SQLITE_IOCAP_ATOMIC4K 0x00000010
607 #define SQLITE_IOCAP_ATOMIC8K 0x00000020
608 #define SQLITE_IOCAP_ATOMIC16K 0x00000040
609 #define SQLITE_IOCAP_ATOMIC32K 0x00000080
610 #define SQLITE_IOCAP_ATOMIC64K 0x00000100
611 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
612 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
613 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
614 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
615 #define SQLITE_IOCAP_IMMUTABLE 0x00002000
616 #define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000
619 ** CAPI3REF: File Locking Levels
621 ** SQLite uses one of these integer values as the second
622 ** argument to calls it makes to the xLock() and xUnlock() methods
623 ** of an [sqlite3_io_methods] object.
625 #define SQLITE_LOCK_NONE 0
626 #define SQLITE_LOCK_SHARED 1
627 #define SQLITE_LOCK_RESERVED 2
628 #define SQLITE_LOCK_PENDING 3
629 #define SQLITE_LOCK_EXCLUSIVE 4
632 ** CAPI3REF: Synchronization Type Flags
634 ** When SQLite invokes the xSync() method of an
635 ** [sqlite3_io_methods] object it uses a combination of
636 ** these integer values as the second argument.
638 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
639 ** sync operation only needs to flush data to mass storage. Inode
640 ** information need not be flushed. If the lower four bits of the flag
641 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
642 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
643 ** to use Mac OS X style fullsync instead of fsync().
645 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
646 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
647 ** settings. The [synchronous pragma] determines when calls to the
648 ** xSync VFS method occur and applies uniformly across all platforms.
649 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
650 ** energetic or rigorous or forceful the sync operations are and
651 ** only make a difference on Mac OSX for the default SQLite code.
652 ** (Third-party VFS implementations might also make the distinction
653 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
654 ** operating systems natively supported by SQLite, only Mac OSX
655 ** cares about the difference.)
657 #define SQLITE_SYNC_NORMAL 0x00002
658 #define SQLITE_SYNC_FULL 0x00003
659 #define SQLITE_SYNC_DATAONLY 0x00010
662 ** CAPI3REF: OS Interface Open File Handle
664 ** An [sqlite3_file] object represents an open file in the
665 ** [sqlite3_vfs | OS interface layer]. Individual OS interface
666 ** implementations will
667 ** want to subclass this object by appending additional fields
668 ** for their own use. The pMethods entry is a pointer to an
669 ** [sqlite3_io_methods] object that defines methods for performing
670 ** I/O operations on the open file.
672 typedef struct sqlite3_file sqlite3_file;
673 struct sqlite3_file {
674 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
678 ** CAPI3REF: OS Interface File Virtual Methods Object
680 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
681 ** [sqlite3_file] object (or, more commonly, a subclass of the
682 ** [sqlite3_file] object) with a pointer to an instance of this object.
683 ** This object defines the methods used to perform various operations
684 ** against the open file represented by the [sqlite3_file] object.
686 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
687 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
688 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
689 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
690 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
691 ** to NULL.
693 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
694 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
695 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
696 ** flag may be ORed in to indicate that only the data of the file
697 ** and not its inode needs to be synced.
699 ** The integer values to xLock() and xUnlock() are one of
700 ** <ul>
701 ** <li> [SQLITE_LOCK_NONE],
702 ** <li> [SQLITE_LOCK_SHARED],
703 ** <li> [SQLITE_LOCK_RESERVED],
704 ** <li> [SQLITE_LOCK_PENDING], or
705 ** <li> [SQLITE_LOCK_EXCLUSIVE].
706 ** </ul>
707 ** xLock() increases the lock. xUnlock() decreases the lock.
708 ** The xCheckReservedLock() method checks whether any database connection,
709 ** either in this process or in some other process, is holding a RESERVED,
710 ** PENDING, or EXCLUSIVE lock on the file. It returns true
711 ** if such a lock exists and false otherwise.
713 ** The xFileControl() method is a generic interface that allows custom
714 ** VFS implementations to directly control an open file using the
715 ** [sqlite3_file_control()] interface. The second "op" argument is an
716 ** integer opcode. The third argument is a generic pointer intended to
717 ** point to a structure that may contain arguments or space in which to
718 ** write return values. Potential uses for xFileControl() might be
719 ** functions to enable blocking locks with timeouts, to change the
720 ** locking strategy (for example to use dot-file locks), to inquire
721 ** about the status of a lock, or to break stale locks. The SQLite
722 ** core reserves all opcodes less than 100 for its own use.
723 ** A [file control opcodes | list of opcodes] less than 100 is available.
724 ** Applications that define a custom xFileControl method should use opcodes
725 ** greater than 100 to avoid conflicts. VFS implementations should
726 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
727 ** recognize.
729 ** The xSectorSize() method returns the sector size of the
730 ** device that underlies the file. The sector size is the
731 ** minimum write that can be performed without disturbing
732 ** other bytes in the file. The xDeviceCharacteristics()
733 ** method returns a bit vector describing behaviors of the
734 ** underlying device:
736 ** <ul>
737 ** <li> [SQLITE_IOCAP_ATOMIC]
738 ** <li> [SQLITE_IOCAP_ATOMIC512]
739 ** <li> [SQLITE_IOCAP_ATOMIC1K]
740 ** <li> [SQLITE_IOCAP_ATOMIC2K]
741 ** <li> [SQLITE_IOCAP_ATOMIC4K]
742 ** <li> [SQLITE_IOCAP_ATOMIC8K]
743 ** <li> [SQLITE_IOCAP_ATOMIC16K]
744 ** <li> [SQLITE_IOCAP_ATOMIC32K]
745 ** <li> [SQLITE_IOCAP_ATOMIC64K]
746 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
747 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
748 ** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
749 ** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
750 ** <li> [SQLITE_IOCAP_IMMUTABLE]
751 ** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
752 ** </ul>
754 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
755 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
756 ** mean that writes of blocks that are nnn bytes in size and
757 ** are aligned to an address which is an integer multiple of
758 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
759 ** that when data is appended to a file, the data is appended
760 ** first then the size of the file is extended, never the other
761 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
762 ** information is written to disk in the same order as calls
763 ** to xWrite().
765 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
766 ** in the unread portions of the buffer with zeros. A VFS that
767 ** fails to zero-fill short reads might seem to work. However,
768 ** failure to zero-fill short reads will eventually lead to
769 ** database corruption.
771 typedef struct sqlite3_io_methods sqlite3_io_methods;
772 struct sqlite3_io_methods {
773 int iVersion;
774 int (*xClose)(sqlite3_file*);
775 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
776 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
777 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
778 int (*xSync)(sqlite3_file*, int flags);
779 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
780 int (*xLock)(sqlite3_file*, int);
781 int (*xUnlock)(sqlite3_file*, int);
782 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
783 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
784 int (*xSectorSize)(sqlite3_file*);
785 int (*xDeviceCharacteristics)(sqlite3_file*);
786 /* Methods above are valid for version 1 */
787 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
788 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
789 void (*xShmBarrier)(sqlite3_file*);
790 int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
791 /* Methods above are valid for version 2 */
792 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
793 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
794 /* Methods above are valid for version 3 */
795 /* Additional methods may be added in future releases */
799 ** CAPI3REF: Standard File Control Opcodes
800 ** KEYWORDS: {file control opcodes} {file control opcode}
802 ** These integer constants are opcodes for the xFileControl method
803 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
804 ** interface.
806 ** <ul>
807 ** <li>[[SQLITE_FCNTL_LOCKSTATE]]
808 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
809 ** opcode causes the xFileControl method to write the current state of
810 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
811 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
812 ** into an integer that the pArg argument points to. This capability
813 ** is used during testing and is only available when the SQLITE_TEST
814 ** compile-time option is used.
816 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
817 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
818 ** layer a hint of how large the database file will grow to be during the
819 ** current transaction. This hint is not guaranteed to be accurate but it
820 ** is often close. The underlying VFS might choose to preallocate database
821 ** file space based on this hint in order to help writes to the database
822 ** file run faster.
824 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
825 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
826 ** extends and truncates the database file in chunks of a size specified
827 ** by the user. The fourth argument to [sqlite3_file_control()] should
828 ** point to an integer (type int) containing the new chunk-size to use
829 ** for the nominated database. Allocating database file space in large
830 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
831 ** improve performance on some systems.
833 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
834 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
835 ** to the [sqlite3_file] object associated with a particular database
836 ** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER].
838 ** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
839 ** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
840 ** to the [sqlite3_file] object associated with the journal file (either
841 ** the [rollback journal] or the [write-ahead log]) for a particular database
842 ** connection. See also [SQLITE_FCNTL_FILE_POINTER].
844 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
845 ** No longer in use.
847 ** <li>[[SQLITE_FCNTL_SYNC]]
848 ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
849 ** sent to the VFS immediately before the xSync method is invoked on a
850 ** database file descriptor. Or, if the xSync method is not invoked
851 ** because the user has configured SQLite with
852 ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
853 ** of the xSync method. In most cases, the pointer argument passed with
854 ** this file-control is NULL. However, if the database file is being synced
855 ** as part of a multi-database commit, the argument points to a nul-terminated
856 ** string containing the transactions master-journal file name. VFSes that
857 ** do not need this signal should silently ignore this opcode. Applications
858 ** should not call [sqlite3_file_control()] with this opcode as doing so may
859 ** disrupt the operation of the specialized VFSes that do require it.
861 ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
862 ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
863 ** and sent to the VFS after a transaction has been committed immediately
864 ** but before the database is unlocked. VFSes that do not need this signal
865 ** should silently ignore this opcode. Applications should not call
866 ** [sqlite3_file_control()] with this opcode as doing so may disrupt the
867 ** operation of the specialized VFSes that do require it.
869 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
870 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
871 ** retry counts and intervals for certain disk I/O operations for the
872 ** windows [VFS] in order to provide robustness in the presence of
873 ** anti-virus programs. By default, the windows VFS will retry file read,
874 ** file write, and file delete operations up to 10 times, with a delay
875 ** of 25 milliseconds before the first retry and with the delay increasing
876 ** by an additional 25 milliseconds with each subsequent retry. This
877 ** opcode allows these two values (10 retries and 25 milliseconds of delay)
878 ** to be adjusted. The values are changed for all database connections
879 ** within the same process. The argument is a pointer to an array of two
880 ** integers where the first integer is the new retry count and the second
881 ** integer is the delay. If either integer is negative, then the setting
882 ** is not changed but instead the prior value of that setting is written
883 ** into the array entry, allowing the current retry settings to be
884 ** interrogated. The zDbName parameter is ignored.
886 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
887 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
888 ** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
889 ** write ahead log and shared memory files used for transaction control
890 ** are automatically deleted when the latest connection to the database
891 ** closes. Setting persistent WAL mode causes those files to persist after
892 ** close. Persisting the files is useful when other processes that do not
893 ** have write permission on the directory containing the database file want
894 ** to read the database file, as the WAL and shared memory files must exist
895 ** in order for the database to be readable. The fourth parameter to
896 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
897 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
898 ** WAL mode. If the integer is -1, then it is overwritten with the current
899 ** WAL persistence setting.
901 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
902 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
903 ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
904 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
905 ** xDeviceCharacteristics methods. The fourth parameter to
906 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
907 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
908 ** mode. If the integer is -1, then it is overwritten with the current
909 ** zero-damage mode setting.
911 ** <li>[[SQLITE_FCNTL_OVERWRITE]]
912 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
913 ** a write transaction to indicate that, unless it is rolled back for some
914 ** reason, the entire database file will be overwritten by the current
915 ** transaction. This is used by VACUUM operations.
917 ** <li>[[SQLITE_FCNTL_VFSNAME]]
918 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
919 ** all [VFSes] in the VFS stack. The names are of all VFS shims and the
920 ** final bottom-level VFS are written into memory obtained from
921 ** [sqlite3_malloc()] and the result is stored in the char* variable
922 ** that the fourth parameter of [sqlite3_file_control()] points to.
923 ** The caller is responsible for freeing the memory when done. As with
924 ** all file-control actions, there is no guarantee that this will actually
925 ** do anything. Callers should initialize the char* variable to a NULL
926 ** pointer in case this file-control is not implemented. This file-control
927 ** is intended for diagnostic use only.
929 ** <li>[[SQLITE_FCNTL_VFS_POINTER]]
930 ** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
931 ** [VFSes] currently in use. ^(The argument X in
932 ** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
933 ** of type "[sqlite3_vfs] **". This opcodes will set *X
934 ** to a pointer to the top-level VFS.)^
935 ** ^When there are multiple VFS shims in the stack, this opcode finds the
936 ** upper-most shim only.
938 ** <li>[[SQLITE_FCNTL_PRAGMA]]
939 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
940 ** file control is sent to the open [sqlite3_file] object corresponding
941 ** to the database file to which the pragma statement refers. ^The argument
942 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
943 ** pointers to strings (char**) in which the second element of the array
944 ** is the name of the pragma and the third element is the argument to the
945 ** pragma or NULL if the pragma has no argument. ^The handler for an
946 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
947 ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
948 ** or the equivalent and that string will become the result of the pragma or
949 ** the error message if the pragma fails. ^If the
950 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
951 ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
952 ** file control returns [SQLITE_OK], then the parser assumes that the
953 ** VFS has handled the PRAGMA itself and the parser generates a no-op
954 ** prepared statement if result string is NULL, or that returns a copy
955 ** of the result string if the string is non-NULL.
956 ** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
957 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
958 ** that the VFS encountered an error while handling the [PRAGMA] and the
959 ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
960 ** file control occurs at the beginning of pragma statement analysis and so
961 ** it is able to override built-in [PRAGMA] statements.
963 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
964 ** ^The [SQLITE_FCNTL_BUSYHANDLER]
965 ** file-control may be invoked by SQLite on the database file handle
966 ** shortly after it is opened in order to provide a custom VFS with access
967 ** to the connections busy-handler callback. The argument is of type (void **)
968 ** - an array of two (void *) values. The first (void *) actually points
969 ** to a function of type (int (*)(void *)). In order to invoke the connections
970 ** busy-handler, this function should be invoked with the second (void *) in
971 ** the array as the only argument. If it returns non-zero, then the operation
972 ** should be retried. If it returns zero, the custom VFS should abandon the
973 ** current operation.
975 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
976 ** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
977 ** to have SQLite generate a
978 ** temporary filename using the same algorithm that is followed to generate
979 ** temporary filenames for TEMP tables and other internal uses. The
980 ** argument should be a char** which will be filled with the filename
981 ** written into memory obtained from [sqlite3_malloc()]. The caller should
982 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
984 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
985 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
986 ** maximum number of bytes that will be used for memory-mapped I/O.
987 ** The argument is a pointer to a value of type sqlite3_int64 that
988 ** is an advisory maximum number of bytes in the file to memory map. The
989 ** pointer is overwritten with the old value. The limit is not changed if
990 ** the value originally pointed to is negative, and so the current limit
991 ** can be queried by passing in a pointer to a negative number. This
992 ** file-control is used internally to implement [PRAGMA mmap_size].
994 ** <li>[[SQLITE_FCNTL_TRACE]]
995 ** The [SQLITE_FCNTL_TRACE] file control provides advisory information
996 ** to the VFS about what the higher layers of the SQLite stack are doing.
997 ** This file control is used by some VFS activity tracing [shims].
998 ** The argument is a zero-terminated string. Higher layers in the
999 ** SQLite stack may generate instances of this file control if
1000 ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
1002 ** <li>[[SQLITE_FCNTL_HAS_MOVED]]
1003 ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
1004 ** pointer to an integer and it writes a boolean into that integer depending
1005 ** on whether or not the file has been renamed, moved, or deleted since it
1006 ** was first opened.
1008 ** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
1009 ** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
1010 ** underlying native file handle associated with a file handle. This file
1011 ** control interprets its argument as a pointer to a native file handle and
1012 ** writes the resulting value there.
1014 ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
1015 ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This
1016 ** opcode causes the xFileControl method to swap the file handle with the one
1017 ** pointed to by the pArg argument. This capability is used during testing
1018 ** and only needs to be supported when SQLITE_TEST is defined.
1020 ** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
1021 ** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
1022 ** be advantageous to block on the next WAL lock if the lock is not immediately
1023 ** available. The WAL subsystem issues this signal during rare
1024 ** circumstances in order to fix a problem with priority inversion.
1025 ** Applications should <em>not</em> use this file-control.
1027 ** <li>[[SQLITE_FCNTL_ZIPVFS]]
1028 ** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
1029 ** VFS should return SQLITE_NOTFOUND for this opcode.
1031 ** <li>[[SQLITE_FCNTL_RBU]]
1032 ** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
1033 ** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for
1034 ** this opcode.
1036 ** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
1037 ** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
1038 ** the file descriptor is placed in "batch write mode", which
1039 ** means all subsequent write operations will be deferred and done
1040 ** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems
1041 ** that do not support batch atomic writes will return SQLITE_NOTFOUND.
1042 ** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
1043 ** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
1044 ** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
1045 ** no VFS interface calls on the same [sqlite3_file] file descriptor
1046 ** except for calls to the xWrite method and the xFileControl method
1047 ** with [SQLITE_FCNTL_SIZE_HINT].
1049 ** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
1050 ** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
1051 ** operations since the previous successful call to
1052 ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
1053 ** This file control returns [SQLITE_OK] if and only if the writes were
1054 ** all performed successfully and have been committed to persistent storage.
1055 ** ^Regardless of whether or not it is successful, this file control takes
1056 ** the file descriptor out of batch write mode so that all subsequent
1057 ** write operations are independent.
1058 ** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
1059 ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1061 ** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
1062 ** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
1063 ** operations since the previous successful call to
1064 ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
1065 ** ^This file control takes the file descriptor out of batch write mode
1066 ** so that all subsequent write operations are independent.
1067 ** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
1068 ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1070 ** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]]
1071 ** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode causes attempts to obtain
1072 ** a file lock using the xLock or xShmLock methods of the VFS to wait
1073 ** for up to M milliseconds before failing, where M is the single
1074 ** unsigned integer parameter.
1075 ** </ul>
1077 #define SQLITE_FCNTL_LOCKSTATE 1
1078 #define SQLITE_FCNTL_GET_LOCKPROXYFILE 2
1079 #define SQLITE_FCNTL_SET_LOCKPROXYFILE 3
1080 #define SQLITE_FCNTL_LAST_ERRNO 4
1081 #define SQLITE_FCNTL_SIZE_HINT 5
1082 #define SQLITE_FCNTL_CHUNK_SIZE 6
1083 #define SQLITE_FCNTL_FILE_POINTER 7
1084 #define SQLITE_FCNTL_SYNC_OMITTED 8
1085 #define SQLITE_FCNTL_WIN32_AV_RETRY 9
1086 #define SQLITE_FCNTL_PERSIST_WAL 10
1087 #define SQLITE_FCNTL_OVERWRITE 11
1088 #define SQLITE_FCNTL_VFSNAME 12
1089 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
1090 #define SQLITE_FCNTL_PRAGMA 14
1091 #define SQLITE_FCNTL_BUSYHANDLER 15
1092 #define SQLITE_FCNTL_TEMPFILENAME 16
1093 #define SQLITE_FCNTL_MMAP_SIZE 18
1094 #define SQLITE_FCNTL_TRACE 19
1095 #define SQLITE_FCNTL_HAS_MOVED 20
1096 #define SQLITE_FCNTL_SYNC 21
1097 #define SQLITE_FCNTL_COMMIT_PHASETWO 22
1098 #define SQLITE_FCNTL_WIN32_SET_HANDLE 23
1099 #define SQLITE_FCNTL_WAL_BLOCK 24
1100 #define SQLITE_FCNTL_ZIPVFS 25
1101 #define SQLITE_FCNTL_RBU 26
1102 #define SQLITE_FCNTL_VFS_POINTER 27
1103 #define SQLITE_FCNTL_JOURNAL_POINTER 28
1104 #define SQLITE_FCNTL_WIN32_GET_HANDLE 29
1105 #define SQLITE_FCNTL_PDB 30
1106 #define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31
1107 #define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32
1108 #define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33
1109 #define SQLITE_FCNTL_LOCK_TIMEOUT 34
1111 /* deprecated names */
1112 #define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE
1113 #define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE
1114 #define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO
1118 ** CAPI3REF: Mutex Handle
1120 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
1121 ** abstract type for a mutex object. The SQLite core never looks
1122 ** at the internal representation of an [sqlite3_mutex]. It only
1123 ** deals with pointers to the [sqlite3_mutex] object.
1125 ** Mutexes are created using [sqlite3_mutex_alloc()].
1127 typedef struct sqlite3_mutex sqlite3_mutex;
1130 ** CAPI3REF: Loadable Extension Thunk
1132 ** A pointer to the opaque sqlite3_api_routines structure is passed as
1133 ** the third parameter to entry points of [loadable extensions]. This
1134 ** structure must be typedefed in order to work around compiler warnings
1135 ** on some platforms.
1137 typedef struct sqlite3_api_routines sqlite3_api_routines;
1140 ** CAPI3REF: OS Interface Object
1142 ** An instance of the sqlite3_vfs object defines the interface between
1143 ** the SQLite core and the underlying operating system. The "vfs"
1144 ** in the name of the object stands for "virtual file system". See
1145 ** the [VFS | VFS documentation] for further information.
1147 ** The VFS interface is sometimes extended by adding new methods onto
1148 ** the end. Each time such an extension occurs, the iVersion field
1149 ** is incremented. The iVersion value started out as 1 in
1150 ** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
1151 ** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
1152 ** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields
1153 ** may be appended to the sqlite3_vfs object and the iVersion value
1154 ** may increase again in future versions of SQLite.
1155 ** Note that the structure
1156 ** of the sqlite3_vfs object changes in the transition from
1157 ** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
1158 ** and yet the iVersion field was not modified.
1160 ** The szOsFile field is the size of the subclassed [sqlite3_file]
1161 ** structure used by this VFS. mxPathname is the maximum length of
1162 ** a pathname in this VFS.
1164 ** Registered sqlite3_vfs objects are kept on a linked list formed by
1165 ** the pNext pointer. The [sqlite3_vfs_register()]
1166 ** and [sqlite3_vfs_unregister()] interfaces manage this list
1167 ** in a thread-safe way. The [sqlite3_vfs_find()] interface
1168 ** searches the list. Neither the application code nor the VFS
1169 ** implementation should use the pNext pointer.
1171 ** The pNext field is the only field in the sqlite3_vfs
1172 ** structure that SQLite will ever modify. SQLite will only access
1173 ** or modify this field while holding a particular static mutex.
1174 ** The application should never modify anything within the sqlite3_vfs
1175 ** object once the object has been registered.
1177 ** The zName field holds the name of the VFS module. The name must
1178 ** be unique across all VFS modules.
1180 ** [[sqlite3_vfs.xOpen]]
1181 ** ^SQLite guarantees that the zFilename parameter to xOpen
1182 ** is either a NULL pointer or string obtained
1183 ** from xFullPathname() with an optional suffix added.
1184 ** ^If a suffix is added to the zFilename parameter, it will
1185 ** consist of a single "-" character followed by no more than
1186 ** 11 alphanumeric and/or "-" characters.
1187 ** ^SQLite further guarantees that
1188 ** the string will be valid and unchanged until xClose() is
1189 ** called. Because of the previous sentence,
1190 ** the [sqlite3_file] can safely store a pointer to the
1191 ** filename if it needs to remember the filename for some reason.
1192 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1193 ** must invent its own temporary name for the file. ^Whenever the
1194 ** xFilename parameter is NULL it will also be the case that the
1195 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1197 ** The flags argument to xOpen() includes all bits set in
1198 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
1199 ** or [sqlite3_open16()] is used, then flags includes at least
1200 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1201 ** If xOpen() opens a file read-only then it sets *pOutFlags to
1202 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
1204 ** ^(SQLite will also add one of the following flags to the xOpen()
1205 ** call, depending on the object being opened:
1207 ** <ul>
1208 ** <li> [SQLITE_OPEN_MAIN_DB]
1209 ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
1210 ** <li> [SQLITE_OPEN_TEMP_DB]
1211 ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
1212 ** <li> [SQLITE_OPEN_TRANSIENT_DB]
1213 ** <li> [SQLITE_OPEN_SUBJOURNAL]
1214 ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
1215 ** <li> [SQLITE_OPEN_WAL]
1216 ** </ul>)^
1218 ** The file I/O implementation can use the object type flags to
1219 ** change the way it deals with files. For example, an application
1220 ** that does not care about crash recovery or rollback might make
1221 ** the open of a journal file a no-op. Writes to this journal would
1222 ** also be no-ops, and any attempt to read the journal would return
1223 ** SQLITE_IOERR. Or the implementation might recognize that a database
1224 ** file will be doing page-aligned sector reads and writes in a random
1225 ** order and set up its I/O subsystem accordingly.
1227 ** SQLite might also add one of the following flags to the xOpen method:
1229 ** <ul>
1230 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
1231 ** <li> [SQLITE_OPEN_EXCLUSIVE]
1232 ** </ul>
1234 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1235 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1236 ** will be set for TEMP databases and their journals, transient
1237 ** databases, and subjournals.
1239 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1240 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1241 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1242 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1243 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1244 ** be created, and that it is an error if it already exists.
1245 ** It is <i>not</i> used to indicate the file should be opened
1246 ** for exclusive access.
1248 ** ^At least szOsFile bytes of memory are allocated by SQLite
1249 ** to hold the [sqlite3_file] structure passed as the third
1250 ** argument to xOpen. The xOpen method does not have to
1251 ** allocate the structure; it should just fill it in. Note that
1252 ** the xOpen method must set the sqlite3_file.pMethods to either
1253 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1254 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1255 ** element will be valid after xOpen returns regardless of the success
1256 ** or failure of the xOpen call.
1258 ** [[sqlite3_vfs.xAccess]]
1259 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1260 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1261 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1262 ** to test whether a file is at least readable. The file can be a
1263 ** directory.
1265 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1266 ** output buffer xFullPathname. The exact size of the output buffer
1267 ** is also passed as a parameter to both methods. If the output buffer
1268 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1269 ** handled as a fatal error by SQLite, vfs implementations should endeavor
1270 ** to prevent this by setting mxPathname to a sufficiently large value.
1272 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1273 ** interfaces are not strictly a part of the filesystem, but they are
1274 ** included in the VFS structure for completeness.
1275 ** The xRandomness() function attempts to return nBytes bytes
1276 ** of good-quality randomness into zOut. The return value is
1277 ** the actual number of bytes of randomness obtained.
1278 ** The xSleep() method causes the calling thread to sleep for at
1279 ** least the number of microseconds given. ^The xCurrentTime()
1280 ** method returns a Julian Day Number for the current date and time as
1281 ** a floating point value.
1282 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1283 ** Day Number multiplied by 86400000 (the number of milliseconds in
1284 ** a 24-hour day).
1285 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1286 ** date and time if that method is available (if iVersion is 2 or
1287 ** greater and the function pointer is not NULL) and will fall back
1288 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1290 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1291 ** are not used by the SQLite core. These optional interfaces are provided
1292 ** by some VFSes to facilitate testing of the VFS code. By overriding
1293 ** system calls with functions under its control, a test program can
1294 ** simulate faults and error conditions that would otherwise be difficult
1295 ** or impossible to induce. The set of system calls that can be overridden
1296 ** varies from one VFS to another, and from one version of the same VFS to the
1297 ** next. Applications that use these interfaces must be prepared for any
1298 ** or all of these interfaces to be NULL or for their behavior to change
1299 ** from one release to the next. Applications must not attempt to access
1300 ** any of these methods if the iVersion of the VFS is less than 3.
1302 typedef struct sqlite3_vfs sqlite3_vfs;
1303 typedef void (*sqlite3_syscall_ptr)(void);
1304 struct sqlite3_vfs {
1305 int iVersion; /* Structure version number (currently 3) */
1306 int szOsFile; /* Size of subclassed sqlite3_file */
1307 int mxPathname; /* Maximum file pathname length */
1308 sqlite3_vfs *pNext; /* Next registered VFS */
1309 const char *zName; /* Name of this virtual file system */
1310 void *pAppData; /* Pointer to application-specific data */
1311 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1312 int flags, int *pOutFlags);
1313 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1314 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1315 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1316 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1317 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1318 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1319 void (*xDlClose)(sqlite3_vfs*, void*);
1320 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1321 int (*xSleep)(sqlite3_vfs*, int microseconds);
1322 int (*xCurrentTime)(sqlite3_vfs*, double*);
1323 int (*xGetLastError)(sqlite3_vfs*, int, char *);
1325 ** The methods above are in version 1 of the sqlite_vfs object
1326 ** definition. Those that follow are added in version 2 or later
1328 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1330 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1331 ** Those below are for version 3 and greater.
1333 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1334 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1335 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1337 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1338 ** New fields may be appended in future versions. The iVersion
1339 ** value will increment whenever this happens.
1344 ** CAPI3REF: Flags for the xAccess VFS method
1346 ** These integer constants can be used as the third parameter to
1347 ** the xAccess method of an [sqlite3_vfs] object. They determine
1348 ** what kind of permissions the xAccess method is looking for.
1349 ** With SQLITE_ACCESS_EXISTS, the xAccess method
1350 ** simply checks whether the file exists.
1351 ** With SQLITE_ACCESS_READWRITE, the xAccess method
1352 ** checks whether the named directory is both readable and writable
1353 ** (in other words, if files can be added, removed, and renamed within
1354 ** the directory).
1355 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1356 ** [temp_store_directory pragma], though this could change in a future
1357 ** release of SQLite.
1358 ** With SQLITE_ACCESS_READ, the xAccess method
1359 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1360 ** currently unused, though it might be used in a future release of
1361 ** SQLite.
1363 #define SQLITE_ACCESS_EXISTS 0
1364 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1365 #define SQLITE_ACCESS_READ 2 /* Unused */
1368 ** CAPI3REF: Flags for the xShmLock VFS method
1370 ** These integer constants define the various locking operations
1371 ** allowed by the xShmLock method of [sqlite3_io_methods]. The
1372 ** following are the only legal combinations of flags to the
1373 ** xShmLock method:
1375 ** <ul>
1376 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1377 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1378 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1379 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1380 ** </ul>
1382 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1383 ** was given on the corresponding lock.
1385 ** The xShmLock method can transition between unlocked and SHARED or
1386 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1387 ** and EXCLUSIVE.
1389 #define SQLITE_SHM_UNLOCK 1
1390 #define SQLITE_SHM_LOCK 2
1391 #define SQLITE_SHM_SHARED 4
1392 #define SQLITE_SHM_EXCLUSIVE 8
1395 ** CAPI3REF: Maximum xShmLock index
1397 ** The xShmLock method on [sqlite3_io_methods] may use values
1398 ** between 0 and this upper bound as its "offset" argument.
1399 ** The SQLite core will never attempt to acquire or release a
1400 ** lock outside of this range
1402 #define SQLITE_SHM_NLOCK 8
1406 ** CAPI3REF: Initialize The SQLite Library
1408 ** ^The sqlite3_initialize() routine initializes the
1409 ** SQLite library. ^The sqlite3_shutdown() routine
1410 ** deallocates any resources that were allocated by sqlite3_initialize().
1411 ** These routines are designed to aid in process initialization and
1412 ** shutdown on embedded systems. Workstation applications using
1413 ** SQLite normally do not need to invoke either of these routines.
1415 ** A call to sqlite3_initialize() is an "effective" call if it is
1416 ** the first time sqlite3_initialize() is invoked during the lifetime of
1417 ** the process, or if it is the first time sqlite3_initialize() is invoked
1418 ** following a call to sqlite3_shutdown(). ^(Only an effective call
1419 ** of sqlite3_initialize() does any initialization. All other calls
1420 ** are harmless no-ops.)^
1422 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1423 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1424 ** an effective call to sqlite3_shutdown() does any deinitialization.
1425 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1427 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1428 ** is not. The sqlite3_shutdown() interface must only be called from a
1429 ** single thread. All open [database connections] must be closed and all
1430 ** other SQLite resources must be deallocated prior to invoking
1431 ** sqlite3_shutdown().
1433 ** Among other things, ^sqlite3_initialize() will invoke
1434 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1435 ** will invoke sqlite3_os_end().
1437 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1438 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1439 ** the library (perhaps it is unable to allocate a needed resource such
1440 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1442 ** ^The sqlite3_initialize() routine is called internally by many other
1443 ** SQLite interfaces so that an application usually does not need to
1444 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1445 ** calls sqlite3_initialize() so the SQLite library will be automatically
1446 ** initialized when [sqlite3_open()] is called if it has not be initialized
1447 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1448 ** compile-time option, then the automatic calls to sqlite3_initialize()
1449 ** are omitted and the application must call sqlite3_initialize() directly
1450 ** prior to using any other SQLite interface. For maximum portability,
1451 ** it is recommended that applications always invoke sqlite3_initialize()
1452 ** directly prior to using any other SQLite interface. Future releases
1453 ** of SQLite may require this. In other words, the behavior exhibited
1454 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1455 ** default behavior in some future release of SQLite.
1457 ** The sqlite3_os_init() routine does operating-system specific
1458 ** initialization of the SQLite library. The sqlite3_os_end()
1459 ** routine undoes the effect of sqlite3_os_init(). Typical tasks
1460 ** performed by these routines include allocation or deallocation
1461 ** of static resources, initialization of global variables,
1462 ** setting up a default [sqlite3_vfs] module, or setting up
1463 ** a default configuration using [sqlite3_config()].
1465 ** The application should never invoke either sqlite3_os_init()
1466 ** or sqlite3_os_end() directly. The application should only invoke
1467 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1468 ** interface is called automatically by sqlite3_initialize() and
1469 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1470 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1471 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1472 ** When [custom builds | built for other platforms]
1473 ** (using the [SQLITE_OS_OTHER=1] compile-time
1474 ** option) the application must supply a suitable implementation for
1475 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1476 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1477 ** must return [SQLITE_OK] on success and some other [error code] upon
1478 ** failure.
1480 int sqlite3_initialize(void);
1481 int sqlite3_shutdown(void);
1482 int sqlite3_os_init(void);
1483 int sqlite3_os_end(void);
1486 ** CAPI3REF: Configuring The SQLite Library
1488 ** The sqlite3_config() interface is used to make global configuration
1489 ** changes to SQLite in order to tune SQLite to the specific needs of
1490 ** the application. The default configuration is recommended for most
1491 ** applications and so this routine is usually not necessary. It is
1492 ** provided to support rare applications with unusual needs.
1494 ** <b>The sqlite3_config() interface is not threadsafe. The application
1495 ** must ensure that no other SQLite interfaces are invoked by other
1496 ** threads while sqlite3_config() is running.</b>
1498 ** The sqlite3_config() interface
1499 ** may only be invoked prior to library initialization using
1500 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1501 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1502 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1503 ** Note, however, that ^sqlite3_config() can be called as part of the
1504 ** implementation of an application-defined [sqlite3_os_init()].
1506 ** The first argument to sqlite3_config() is an integer
1507 ** [configuration option] that determines
1508 ** what property of SQLite is to be configured. Subsequent arguments
1509 ** vary depending on the [configuration option]
1510 ** in the first argument.
1512 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1513 ** ^If the option is unknown or SQLite is unable to set the option
1514 ** then this routine returns a non-zero [error code].
1516 int sqlite3_config(int, ...);
1519 ** CAPI3REF: Configure database connections
1520 ** METHOD: sqlite3
1522 ** The sqlite3_db_config() interface is used to make configuration
1523 ** changes to a [database connection]. The interface is similar to
1524 ** [sqlite3_config()] except that the changes apply to a single
1525 ** [database connection] (specified in the first argument).
1527 ** The second argument to sqlite3_db_config(D,V,...) is the
1528 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1529 ** that indicates what aspect of the [database connection] is being configured.
1530 ** Subsequent arguments vary depending on the configuration verb.
1532 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1533 ** the call is considered successful.
1535 int sqlite3_db_config(sqlite3*, int op, ...);
1538 ** CAPI3REF: Memory Allocation Routines
1540 ** An instance of this object defines the interface between SQLite
1541 ** and low-level memory allocation routines.
1543 ** This object is used in only one place in the SQLite interface.
1544 ** A pointer to an instance of this object is the argument to
1545 ** [sqlite3_config()] when the configuration option is
1546 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1547 ** By creating an instance of this object
1548 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1549 ** during configuration, an application can specify an alternative
1550 ** memory allocation subsystem for SQLite to use for all of its
1551 ** dynamic memory needs.
1553 ** Note that SQLite comes with several [built-in memory allocators]
1554 ** that are perfectly adequate for the overwhelming majority of applications
1555 ** and that this object is only useful to a tiny minority of applications
1556 ** with specialized memory allocation requirements. This object is
1557 ** also used during testing of SQLite in order to specify an alternative
1558 ** memory allocator that simulates memory out-of-memory conditions in
1559 ** order to verify that SQLite recovers gracefully from such
1560 ** conditions.
1562 ** The xMalloc, xRealloc, and xFree methods must work like the
1563 ** malloc(), realloc() and free() functions from the standard C library.
1564 ** ^SQLite guarantees that the second argument to
1565 ** xRealloc is always a value returned by a prior call to xRoundup.
1567 ** xSize should return the allocated size of a memory allocation
1568 ** previously obtained from xMalloc or xRealloc. The allocated size
1569 ** is always at least as big as the requested size but may be larger.
1571 ** The xRoundup method returns what would be the allocated size of
1572 ** a memory allocation given a particular requested size. Most memory
1573 ** allocators round up memory allocations at least to the next multiple
1574 ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1575 ** Every memory allocation request coming in through [sqlite3_malloc()]
1576 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1577 ** that causes the corresponding memory allocation to fail.
1579 ** The xInit method initializes the memory allocator. For example,
1580 ** it might allocate any require mutexes or initialize internal data
1581 ** structures. The xShutdown method is invoked (indirectly) by
1582 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1583 ** by xInit. The pAppData pointer is used as the only parameter to
1584 ** xInit and xShutdown.
1586 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1587 ** the xInit method, so the xInit method need not be threadsafe. The
1588 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1589 ** not need to be threadsafe either. For all other methods, SQLite
1590 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1591 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1592 ** it is by default) and so the methods are automatically serialized.
1593 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1594 ** methods must be threadsafe or else make their own arrangements for
1595 ** serialization.
1597 ** SQLite will never invoke xInit() more than once without an intervening
1598 ** call to xShutdown().
1600 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1601 struct sqlite3_mem_methods {
1602 void *(*xMalloc)(int); /* Memory allocation function */
1603 void (*xFree)(void*); /* Free a prior allocation */
1604 void *(*xRealloc)(void*,int); /* Resize an allocation */
1605 int (*xSize)(void*); /* Return the size of an allocation */
1606 int (*xRoundup)(int); /* Round up request size to allocation size */
1607 int (*xInit)(void*); /* Initialize the memory allocator */
1608 void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1609 void *pAppData; /* Argument to xInit() and xShutdown() */
1613 ** CAPI3REF: Configuration Options
1614 ** KEYWORDS: {configuration option}
1616 ** These constants are the available integer configuration options that
1617 ** can be passed as the first argument to the [sqlite3_config()] interface.
1619 ** New configuration options may be added in future releases of SQLite.
1620 ** Existing configuration options might be discontinued. Applications
1621 ** should check the return code from [sqlite3_config()] to make sure that
1622 ** the call worked. The [sqlite3_config()] interface will return a
1623 ** non-zero [error code] if a discontinued or unsupported configuration option
1624 ** is invoked.
1626 ** <dl>
1627 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1628 ** <dd>There are no arguments to this option. ^This option sets the
1629 ** [threading mode] to Single-thread. In other words, it disables
1630 ** all mutexing and puts SQLite into a mode where it can only be used
1631 ** by a single thread. ^If SQLite is compiled with
1632 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1633 ** it is not possible to change the [threading mode] from its default
1634 ** value of Single-thread and so [sqlite3_config()] will return
1635 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1636 ** configuration option.</dd>
1638 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1639 ** <dd>There are no arguments to this option. ^This option sets the
1640 ** [threading mode] to Multi-thread. In other words, it disables
1641 ** mutexing on [database connection] and [prepared statement] objects.
1642 ** The application is responsible for serializing access to
1643 ** [database connections] and [prepared statements]. But other mutexes
1644 ** are enabled so that SQLite will be safe to use in a multi-threaded
1645 ** environment as long as no two threads attempt to use the same
1646 ** [database connection] at the same time. ^If SQLite is compiled with
1647 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1648 ** it is not possible to set the Multi-thread [threading mode] and
1649 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1650 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1652 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1653 ** <dd>There are no arguments to this option. ^This option sets the
1654 ** [threading mode] to Serialized. In other words, this option enables
1655 ** all mutexes including the recursive
1656 ** mutexes on [database connection] and [prepared statement] objects.
1657 ** In this mode (which is the default when SQLite is compiled with
1658 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1659 ** to [database connections] and [prepared statements] so that the
1660 ** application is free to use the same [database connection] or the
1661 ** same [prepared statement] in different threads at the same time.
1662 ** ^If SQLite is compiled with
1663 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1664 ** it is not possible to set the Serialized [threading mode] and
1665 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1666 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1668 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1669 ** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1670 ** a pointer to an instance of the [sqlite3_mem_methods] structure.
1671 ** The argument specifies
1672 ** alternative low-level memory allocation routines to be used in place of
1673 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1674 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1675 ** before the [sqlite3_config()] call returns.</dd>
1677 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1678 ** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1679 ** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1680 ** The [sqlite3_mem_methods]
1681 ** structure is filled with the currently defined memory allocation routines.)^
1682 ** This option can be used to overload the default memory allocation
1683 ** routines with a wrapper that simulations memory allocation failure or
1684 ** tracks memory usage, for example. </dd>
1686 ** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
1687 ** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
1688 ** type int, interpreted as a boolean, which if true provides a hint to
1689 ** SQLite that it should avoid large memory allocations if possible.
1690 ** SQLite will run faster if it is free to make large memory allocations,
1691 ** but some application might prefer to run slower in exchange for
1692 ** guarantees about memory fragmentation that are possible if large
1693 ** allocations are avoided. This hint is normally off.
1694 ** </dd>
1696 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1697 ** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1698 ** interpreted as a boolean, which enables or disables the collection of
1699 ** memory allocation statistics. ^(When memory allocation statistics are
1700 ** disabled, the following SQLite interfaces become non-operational:
1701 ** <ul>
1702 ** <li> [sqlite3_memory_used()]
1703 ** <li> [sqlite3_memory_highwater()]
1704 ** <li> [sqlite3_soft_heap_limit64()]
1705 ** <li> [sqlite3_status64()]
1706 ** </ul>)^
1707 ** ^Memory allocation statistics are enabled by default unless SQLite is
1708 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1709 ** allocation statistics are disabled by default.
1710 ** </dd>
1712 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1713 ** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
1714 ** </dd>
1716 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1717 ** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
1718 ** that SQLite can use for the database page cache with the default page
1719 ** cache implementation.
1720 ** This configuration option is a no-op if an application-define page
1721 ** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
1722 ** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1723 ** 8-byte aligned memory (pMem), the size of each page cache line (sz),
1724 ** and the number of cache lines (N).
1725 ** The sz argument should be the size of the largest database page
1726 ** (a power of two between 512 and 65536) plus some extra bytes for each
1727 ** page header. ^The number of extra bytes needed by the page header
1728 ** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
1729 ** ^It is harmless, apart from the wasted memory,
1730 ** for the sz parameter to be larger than necessary. The pMem
1731 ** argument must be either a NULL pointer or a pointer to an 8-byte
1732 ** aligned block of memory of at least sz*N bytes, otherwise
1733 ** subsequent behavior is undefined.
1734 ** ^When pMem is not NULL, SQLite will strive to use the memory provided
1735 ** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
1736 ** a page cache line is larger than sz bytes or if all of the pMem buffer
1737 ** is exhausted.
1738 ** ^If pMem is NULL and N is non-zero, then each database connection
1739 ** does an initial bulk allocation for page cache memory
1740 ** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
1741 ** of -1024*N bytes if N is negative, . ^If additional
1742 ** page cache memory is needed beyond what is provided by the initial
1743 ** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
1744 ** additional cache line. </dd>
1746 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1747 ** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1748 ** that SQLite will use for all of its dynamic memory allocation needs
1749 ** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
1750 ** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1751 ** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1752 ** [SQLITE_ERROR] if invoked otherwise.
1753 ** ^There are three arguments to SQLITE_CONFIG_HEAP:
1754 ** An 8-byte aligned pointer to the memory,
1755 ** the number of bytes in the memory buffer, and the minimum allocation size.
1756 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1757 ** to using its default memory allocator (the system malloc() implementation),
1758 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1759 ** memory pointer is not NULL then the alternative memory
1760 ** allocator is engaged to handle all of SQLites memory allocation needs.
1761 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1762 ** boundary or subsequent behavior of SQLite will be undefined.
1763 ** The minimum allocation size is capped at 2**12. Reasonable values
1764 ** for the minimum allocation size are 2**5 through 2**8.</dd>
1766 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1767 ** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1768 ** pointer to an instance of the [sqlite3_mutex_methods] structure.
1769 ** The argument specifies alternative low-level mutex routines to be used
1770 ** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of
1771 ** the content of the [sqlite3_mutex_methods] structure before the call to
1772 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1773 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1774 ** the entire mutexing subsystem is omitted from the build and hence calls to
1775 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1776 ** return [SQLITE_ERROR].</dd>
1778 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1779 ** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1780 ** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The
1781 ** [sqlite3_mutex_methods]
1782 ** structure is filled with the currently defined mutex routines.)^
1783 ** This option can be used to overload the default mutex allocation
1784 ** routines with a wrapper used to track mutex usage for performance
1785 ** profiling or testing, for example. ^If SQLite is compiled with
1786 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1787 ** the entire mutexing subsystem is omitted from the build and hence calls to
1788 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1789 ** return [SQLITE_ERROR].</dd>
1791 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1792 ** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1793 ** the default size of lookaside memory on each [database connection].
1794 ** The first argument is the
1795 ** size of each lookaside buffer slot and the second is the number of
1796 ** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE
1797 ** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1798 ** option to [sqlite3_db_config()] can be used to change the lookaside
1799 ** configuration on individual connections.)^ </dd>
1801 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1802 ** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1803 ** a pointer to an [sqlite3_pcache_methods2] object. This object specifies
1804 ** the interface to a custom page cache implementation.)^
1805 ** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1807 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1808 ** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1809 ** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of
1810 ** the current page cache implementation into that object.)^ </dd>
1812 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1813 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1814 ** global [error log].
1815 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1816 ** function with a call signature of void(*)(void*,int,const char*),
1817 ** and a pointer to void. ^If the function pointer is not NULL, it is
1818 ** invoked by [sqlite3_log()] to process each logging event. ^If the
1819 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1820 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1821 ** passed through as the first parameter to the application-defined logger
1822 ** function whenever that function is invoked. ^The second parameter to
1823 ** the logger function is a copy of the first parameter to the corresponding
1824 ** [sqlite3_log()] call and is intended to be a [result code] or an
1825 ** [extended result code]. ^The third parameter passed to the logger is
1826 ** log message after formatting via [sqlite3_snprintf()].
1827 ** The SQLite logging interface is not reentrant; the logger function
1828 ** supplied by the application must not invoke any SQLite interface.
1829 ** In a multi-threaded application, the application-defined logger
1830 ** function must be threadsafe. </dd>
1832 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1833 ** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1834 ** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1835 ** then URI handling is globally disabled.)^ ^If URI handling is globally
1836 ** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1837 ** [sqlite3_open16()] or
1838 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1839 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1840 ** connection is opened. ^If it is globally disabled, filenames are
1841 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1842 ** database connection is opened. ^(By default, URI handling is globally
1843 ** disabled. The default value may be changed by compiling with the
1844 ** [SQLITE_USE_URI] symbol defined.)^
1846 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1847 ** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1848 ** argument which is interpreted as a boolean in order to enable or disable
1849 ** the use of covering indices for full table scans in the query optimizer.
1850 ** ^The default setting is determined
1851 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1852 ** if that compile-time option is omitted.
1853 ** The ability to disable the use of covering indices for full table scans
1854 ** is because some incorrectly coded legacy applications might malfunction
1855 ** when the optimization is enabled. Providing the ability to
1856 ** disable the optimization allows the older, buggy application code to work
1857 ** without change even with newer versions of SQLite.
1859 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1860 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1861 ** <dd> These options are obsolete and should not be used by new code.
1862 ** They are retained for backwards compatibility but are now no-ops.
1863 ** </dd>
1865 ** [[SQLITE_CONFIG_SQLLOG]]
1866 ** <dt>SQLITE_CONFIG_SQLLOG
1867 ** <dd>This option is only available if sqlite is compiled with the
1868 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1869 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1870 ** The second should be of type (void*). The callback is invoked by the library
1871 ** in three separate circumstances, identified by the value passed as the
1872 ** fourth parameter. If the fourth parameter is 0, then the database connection
1873 ** passed as the second argument has just been opened. The third argument
1874 ** points to a buffer containing the name of the main database file. If the
1875 ** fourth parameter is 1, then the SQL statement that the third parameter
1876 ** points to has just been executed. Or, if the fourth parameter is 2, then
1877 ** the connection being passed as the second parameter is being closed. The
1878 ** third parameter is passed NULL In this case. An example of using this
1879 ** configuration option can be seen in the "test_sqllog.c" source file in
1880 ** the canonical SQLite source tree.</dd>
1882 ** [[SQLITE_CONFIG_MMAP_SIZE]]
1883 ** <dt>SQLITE_CONFIG_MMAP_SIZE
1884 ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1885 ** that are the default mmap size limit (the default setting for
1886 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1887 ** ^The default setting can be overridden by each database connection using
1888 ** either the [PRAGMA mmap_size] command, or by using the
1889 ** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size
1890 ** will be silently truncated if necessary so that it does not exceed the
1891 ** compile-time maximum mmap size set by the
1892 ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1893 ** ^If either argument to this option is negative, then that argument is
1894 ** changed to its compile-time default.
1896 ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
1897 ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
1898 ** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
1899 ** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
1900 ** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1901 ** that specifies the maximum size of the created heap.
1903 ** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
1904 ** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
1905 ** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
1906 ** is a pointer to an integer and writes into that integer the number of extra
1907 ** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
1908 ** The amount of extra space required can change depending on the compiler,
1909 ** target platform, and SQLite version.
1911 ** [[SQLITE_CONFIG_PMASZ]]
1912 ** <dt>SQLITE_CONFIG_PMASZ
1913 ** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
1914 ** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
1915 ** sorter to that integer. The default minimum PMA Size is set by the
1916 ** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched
1917 ** to help with sort operations when multithreaded sorting
1918 ** is enabled (using the [PRAGMA threads] command) and the amount of content
1919 ** to be sorted exceeds the page size times the minimum of the
1920 ** [PRAGMA cache_size] setting and this value.
1922 ** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
1923 ** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
1924 ** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
1925 ** becomes the [statement journal] spill-to-disk threshold.
1926 ** [Statement journals] are held in memory until their size (in bytes)
1927 ** exceeds this threshold, at which point they are written to disk.
1928 ** Or if the threshold is -1, statement journals are always held
1929 ** exclusively in memory.
1930 ** Since many statement journals never become large, setting the spill
1931 ** threshold to a value such as 64KiB can greatly reduce the amount of
1932 ** I/O required to support statement rollback.
1933 ** The default value for this setting is controlled by the
1934 ** [SQLITE_STMTJRNL_SPILL] compile-time option.
1936 ** [[SQLITE_CONFIG_SORTERREF_SIZE]]
1937 ** <dt>SQLITE_CONFIG_SORTERREF_SIZE
1938 ** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
1939 ** of type (int) - the new value of the sorter-reference size threshold.
1940 ** Usually, when SQLite uses an external sort to order records according
1941 ** to an ORDER BY clause, all fields required by the caller are present in the
1942 ** sorted records. However, if SQLite determines based on the declared type
1943 ** of a table column that its values are likely to be very large - larger
1944 ** than the configured sorter-reference size threshold - then a reference
1945 ** is stored in each sorted record and the required column values loaded
1946 ** from the database as records are returned in sorted order. The default
1947 ** value for this option is to never use this optimization. Specifying a
1948 ** negative value for this option restores the default behaviour.
1949 ** This option is only available if SQLite is compiled with the
1950 ** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
1951 ** </dl>
1953 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1954 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1955 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1956 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1957 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1958 #define SQLITE_CONFIG_SCRATCH 6 /* No longer used */
1959 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1960 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1961 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1962 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1963 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1964 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1965 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1966 #define SQLITE_CONFIG_PCACHE 14 /* no-op */
1967 #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
1968 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
1969 #define SQLITE_CONFIG_URI 17 /* int */
1970 #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
1971 #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
1972 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
1973 #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
1974 #define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
1975 #define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
1976 #define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */
1977 #define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */
1978 #define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */
1979 #define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */
1980 #define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */
1983 ** CAPI3REF: Database Connection Configuration Options
1985 ** These constants are the available integer configuration options that
1986 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1988 ** New configuration options may be added in future releases of SQLite.
1989 ** Existing configuration options might be discontinued. Applications
1990 ** should check the return code from [sqlite3_db_config()] to make sure that
1991 ** the call worked. ^The [sqlite3_db_config()] interface will return a
1992 ** non-zero [error code] if a discontinued or unsupported configuration option
1993 ** is invoked.
1995 ** <dl>
1996 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1997 ** <dd> ^This option takes three additional arguments that determine the
1998 ** [lookaside memory allocator] configuration for the [database connection].
1999 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
2000 ** pointer to a memory buffer to use for lookaside memory.
2001 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
2002 ** may be NULL in which case SQLite will allocate the
2003 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
2004 ** size of each lookaside buffer slot. ^The third argument is the number of
2005 ** slots. The size of the buffer in the first argument must be greater than
2006 ** or equal to the product of the second and third arguments. The buffer
2007 ** must be aligned to an 8-byte boundary. ^If the second argument to
2008 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
2009 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
2010 ** configuration for a database connection can only be changed when that
2011 ** connection is not currently using lookaside memory, or in other words
2012 ** when the "current value" returned by
2013 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
2014 ** Any attempt to change the lookaside memory configuration when lookaside
2015 ** memory is in use leaves the configuration unchanged and returns
2016 ** [SQLITE_BUSY].)^</dd>
2018 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
2019 ** <dd> ^This option is used to enable or disable the enforcement of
2020 ** [foreign key constraints]. There should be two additional arguments.
2021 ** The first argument is an integer which is 0 to disable FK enforcement,
2022 ** positive to enable FK enforcement or negative to leave FK enforcement
2023 ** unchanged. The second parameter is a pointer to an integer into which
2024 ** is written 0 or 1 to indicate whether FK enforcement is off or on
2025 ** following this call. The second parameter may be a NULL pointer, in
2026 ** which case the FK enforcement setting is not reported back. </dd>
2028 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
2029 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
2030 ** There should be two additional arguments.
2031 ** The first argument is an integer which is 0 to disable triggers,
2032 ** positive to enable triggers or negative to leave the setting unchanged.
2033 ** The second parameter is a pointer to an integer into which
2034 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
2035 ** following this call. The second parameter may be a NULL pointer, in
2036 ** which case the trigger setting is not reported back. </dd>
2038 ** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
2039 ** <dd> ^This option is used to enable or disable the two-argument
2040 ** version of the [fts3_tokenizer()] function which is part of the
2041 ** [FTS3] full-text search engine extension.
2042 ** There should be two additional arguments.
2043 ** The first argument is an integer which is 0 to disable fts3_tokenizer() or
2044 ** positive to enable fts3_tokenizer() or negative to leave the setting
2045 ** unchanged.
2046 ** The second parameter is a pointer to an integer into which
2047 ** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
2048 ** following this call. The second parameter may be a NULL pointer, in
2049 ** which case the new setting is not reported back. </dd>
2051 ** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
2052 ** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
2053 ** interface independently of the [load_extension()] SQL function.
2054 ** The [sqlite3_enable_load_extension()] API enables or disables both the
2055 ** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
2056 ** There should be two additional arguments.
2057 ** When the first argument to this interface is 1, then only the C-API is
2058 ** enabled and the SQL function remains disabled. If the first argument to
2059 ** this interface is 0, then both the C-API and the SQL function are disabled.
2060 ** If the first argument is -1, then no changes are made to state of either the
2061 ** C-API or the SQL function.
2062 ** The second parameter is a pointer to an integer into which
2063 ** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
2064 ** is disabled or enabled following this call. The second parameter may
2065 ** be a NULL pointer, in which case the new setting is not reported back.
2066 ** </dd>
2068 ** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
2069 ** <dd> ^This option is used to change the name of the "main" database
2070 ** schema. ^The sole argument is a pointer to a constant UTF8 string
2071 ** which will become the new schema name in place of "main". ^SQLite
2072 ** does not make a copy of the new main schema name string, so the application
2073 ** must ensure that the argument passed into this DBCONFIG option is unchanged
2074 ** until after the database connection closes.
2075 ** </dd>
2077 ** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
2078 ** <dd> Usually, when a database in wal mode is closed or detached from a
2079 ** database handle, SQLite checks if this will mean that there are now no
2080 ** connections at all to the database. If so, it performs a checkpoint
2081 ** operation before closing the connection. This option may be used to
2082 ** override this behaviour. The first parameter passed to this operation
2083 ** is an integer - positive to disable checkpoints-on-close, or zero (the
2084 ** default) to enable them, and negative to leave the setting unchanged.
2085 ** The second parameter is a pointer to an integer
2086 ** into which is written 0 or 1 to indicate whether checkpoints-on-close
2087 ** have been disabled - 0 if they are not disabled, 1 if they are.
2088 ** </dd>
2090 ** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
2091 ** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
2092 ** the [query planner stability guarantee] (QPSG). When the QPSG is active,
2093 ** a single SQL query statement will always use the same algorithm regardless
2094 ** of values of [bound parameters].)^ The QPSG disables some query optimizations
2095 ** that look at the values of bound parameters, which can make some queries
2096 ** slower. But the QPSG has the advantage of more predictable behavior. With
2097 ** the QPSG active, SQLite will always use the same query plan in the field as
2098 ** was used during testing in the lab.
2099 ** The first argument to this setting is an integer which is 0 to disable
2100 ** the QPSG, positive to enable QPSG, or negative to leave the setting
2101 ** unchanged. The second parameter is a pointer to an integer into which
2102 ** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
2103 ** following this call.
2104 ** </dd>
2106 ** <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
2107 ** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
2108 ** include output for any operations performed by trigger programs. This
2109 ** option is used to set or clear (the default) a flag that governs this
2110 ** behavior. The first parameter passed to this operation is an integer -
2111 ** positive to enable output for trigger programs, or zero to disable it,
2112 ** or negative to leave the setting unchanged.
2113 ** The second parameter is a pointer to an integer into which is written
2114 ** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
2115 ** it is not disabled, 1 if it is.
2116 ** </dd>
2118 ** <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
2119 ** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
2120 ** [VACUUM] in order to reset a database back to an empty database
2121 ** with no schema and no content. The following process works even for
2122 ** a badly corrupted database file:
2123 ** <ol>
2124 ** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
2125 ** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
2126 ** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
2127 ** </ol>
2128 ** Because resetting a database is destructive and irreversible, the
2129 ** process requires the use of this obscure API and multiple steps to help
2130 ** ensure that it does not happen by accident.
2131 ** </dd>
2132 ** </dl>
2134 #define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */
2135 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
2136 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
2137 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
2138 #define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
2139 #define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
2140 #define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */
2141 #define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */
2142 #define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */
2143 #define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */
2144 #define SQLITE_DBCONFIG_MAX 1009 /* Largest DBCONFIG */
2147 ** CAPI3REF: Enable Or Disable Extended Result Codes
2148 ** METHOD: sqlite3
2150 ** ^The sqlite3_extended_result_codes() routine enables or disables the
2151 ** [extended result codes] feature of SQLite. ^The extended result
2152 ** codes are disabled by default for historical compatibility.
2154 int sqlite3_extended_result_codes(sqlite3*, int onoff);
2157 ** CAPI3REF: Last Insert Rowid
2158 ** METHOD: sqlite3
2160 ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
2161 ** has a unique 64-bit signed
2162 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
2163 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
2164 ** names are not also used by explicitly declared columns. ^If
2165 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
2166 ** is another alias for the rowid.
2168 ** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
2169 ** the most recent successful [INSERT] into a rowid table or [virtual table]
2170 ** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
2171 ** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
2172 ** on the database connection D, then sqlite3_last_insert_rowid(D) returns
2173 ** zero.
2175 ** As well as being set automatically as rows are inserted into database
2176 ** tables, the value returned by this function may be set explicitly by
2177 ** [sqlite3_set_last_insert_rowid()]
2179 ** Some virtual table implementations may INSERT rows into rowid tables as
2180 ** part of committing a transaction (e.g. to flush data accumulated in memory
2181 ** to disk). In this case subsequent calls to this function return the rowid
2182 ** associated with these internal INSERT operations, which leads to
2183 ** unintuitive results. Virtual table implementations that do write to rowid
2184 ** tables in this way can avoid this problem by restoring the original
2185 ** rowid value using [sqlite3_set_last_insert_rowid()] before returning
2186 ** control to the user.
2188 ** ^(If an [INSERT] occurs within a trigger then this routine will
2189 ** return the [rowid] of the inserted row as long as the trigger is
2190 ** running. Once the trigger program ends, the value returned
2191 ** by this routine reverts to what it was before the trigger was fired.)^
2193 ** ^An [INSERT] that fails due to a constraint violation is not a
2194 ** successful [INSERT] and does not change the value returned by this
2195 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
2196 ** and INSERT OR ABORT make no changes to the return value of this
2197 ** routine when their insertion fails. ^(When INSERT OR REPLACE
2198 ** encounters a constraint violation, it does not fail. The
2199 ** INSERT continues to completion after deleting rows that caused
2200 ** the constraint problem so INSERT OR REPLACE will always change
2201 ** the return value of this interface.)^
2203 ** ^For the purposes of this routine, an [INSERT] is considered to
2204 ** be successful even if it is subsequently rolled back.
2206 ** This function is accessible to SQL statements via the
2207 ** [last_insert_rowid() SQL function].
2209 ** If a separate thread performs a new [INSERT] on the same
2210 ** database connection while the [sqlite3_last_insert_rowid()]
2211 ** function is running and thus changes the last insert [rowid],
2212 ** then the value returned by [sqlite3_last_insert_rowid()] is
2213 ** unpredictable and might not equal either the old or the new
2214 ** last insert [rowid].
2216 sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
2219 ** CAPI3REF: Set the Last Insert Rowid value.
2220 ** METHOD: sqlite3
2222 ** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
2223 ** set the value returned by calling sqlite3_last_insert_rowid(D) to R
2224 ** without inserting a row into the database.
2226 void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
2229 ** CAPI3REF: Count The Number Of Rows Modified
2230 ** METHOD: sqlite3
2232 ** ^This function returns the number of rows modified, inserted or
2233 ** deleted by the most recently completed INSERT, UPDATE or DELETE
2234 ** statement on the database connection specified by the only parameter.
2235 ** ^Executing any other type of SQL statement does not modify the value
2236 ** returned by this function.
2238 ** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
2239 ** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
2240 ** [foreign key actions] or [REPLACE] constraint resolution are not counted.
2242 ** Changes to a view that are intercepted by
2243 ** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
2244 ** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
2245 ** DELETE statement run on a view is always zero. Only changes made to real
2246 ** tables are counted.
2248 ** Things are more complicated if the sqlite3_changes() function is
2249 ** executed while a trigger program is running. This may happen if the
2250 ** program uses the [changes() SQL function], or if some other callback
2251 ** function invokes sqlite3_changes() directly. Essentially:
2253 ** <ul>
2254 ** <li> ^(Before entering a trigger program the value returned by
2255 ** sqlite3_changes() function is saved. After the trigger program
2256 ** has finished, the original value is restored.)^
2258 ** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
2259 ** statement sets the value returned by sqlite3_changes()
2260 ** upon completion as normal. Of course, this value will not include
2261 ** any changes performed by sub-triggers, as the sqlite3_changes()
2262 ** value will be saved and restored after each sub-trigger has run.)^
2263 ** </ul>
2265 ** ^This means that if the changes() SQL function (or similar) is used
2266 ** by the first INSERT, UPDATE or DELETE statement within a trigger, it
2267 ** returns the value as set when the calling statement began executing.
2268 ** ^If it is used by the second or subsequent such statement within a trigger
2269 ** program, the value returned reflects the number of rows modified by the
2270 ** previous INSERT, UPDATE or DELETE statement within the same trigger.
2272 ** See also the [sqlite3_total_changes()] interface, the
2273 ** [count_changes pragma], and the [changes() SQL function].
2275 ** If a separate thread makes changes on the same database connection
2276 ** while [sqlite3_changes()] is running then the value returned
2277 ** is unpredictable and not meaningful.
2279 int sqlite3_changes(sqlite3*);
2282 ** CAPI3REF: Total Number Of Rows Modified
2283 ** METHOD: sqlite3
2285 ** ^This function returns the total number of rows inserted, modified or
2286 ** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2287 ** since the database connection was opened, including those executed as
2288 ** part of trigger programs. ^Executing any other type of SQL statement
2289 ** does not affect the value returned by sqlite3_total_changes().
2291 ** ^Changes made as part of [foreign key actions] are included in the
2292 ** count, but those made as part of REPLACE constraint resolution are
2293 ** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2294 ** are not counted.
2296 ** See also the [sqlite3_changes()] interface, the
2297 ** [count_changes pragma], and the [total_changes() SQL function].
2299 ** If a separate thread makes changes on the same database connection
2300 ** while [sqlite3_total_changes()] is running then the value
2301 ** returned is unpredictable and not meaningful.
2303 int sqlite3_total_changes(sqlite3*);
2306 ** CAPI3REF: Interrupt A Long-Running Query
2307 ** METHOD: sqlite3
2309 ** ^This function causes any pending database operation to abort and
2310 ** return at its earliest opportunity. This routine is typically
2311 ** called in response to a user action such as pressing "Cancel"
2312 ** or Ctrl-C where the user wants a long query operation to halt
2313 ** immediately.
2315 ** ^It is safe to call this routine from a thread different from the
2316 ** thread that is currently running the database operation. But it
2317 ** is not safe to call this routine with a [database connection] that
2318 ** is closed or might close before sqlite3_interrupt() returns.
2320 ** ^If an SQL operation is very nearly finished at the time when
2321 ** sqlite3_interrupt() is called, then it might not have an opportunity
2322 ** to be interrupted and might continue to completion.
2324 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2325 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2326 ** that is inside an explicit transaction, then the entire transaction
2327 ** will be rolled back automatically.
2329 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
2330 ** SQL statements on [database connection] D complete. ^Any new SQL statements
2331 ** that are started after the sqlite3_interrupt() call and before the
2332 ** running statements reaches zero are interrupted as if they had been
2333 ** running prior to the sqlite3_interrupt() call. ^New SQL statements
2334 ** that are started after the running statement count reaches zero are
2335 ** not effected by the sqlite3_interrupt().
2336 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2337 ** SQL statements is a no-op and has no effect on SQL statements
2338 ** that are started after the sqlite3_interrupt() call returns.
2340 void sqlite3_interrupt(sqlite3*);
2343 ** CAPI3REF: Determine If An SQL Statement Is Complete
2345 ** These routines are useful during command-line input to determine if the
2346 ** currently entered text seems to form a complete SQL statement or
2347 ** if additional input is needed before sending the text into
2348 ** SQLite for parsing. ^These routines return 1 if the input string
2349 ** appears to be a complete SQL statement. ^A statement is judged to be
2350 ** complete if it ends with a semicolon token and is not a prefix of a
2351 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
2352 ** string literals or quoted identifier names or comments are not
2353 ** independent tokens (they are part of the token in which they are
2354 ** embedded) and thus do not count as a statement terminator. ^Whitespace
2355 ** and comments that follow the final semicolon are ignored.
2357 ** ^These routines return 0 if the statement is incomplete. ^If a
2358 ** memory allocation fails, then SQLITE_NOMEM is returned.
2360 ** ^These routines do not parse the SQL statements thus
2361 ** will not detect syntactically incorrect SQL.
2363 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2364 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2365 ** automatically by sqlite3_complete16(). If that initialization fails,
2366 ** then the return value from sqlite3_complete16() will be non-zero
2367 ** regardless of whether or not the input SQL is complete.)^
2369 ** The input to [sqlite3_complete()] must be a zero-terminated
2370 ** UTF-8 string.
2372 ** The input to [sqlite3_complete16()] must be a zero-terminated
2373 ** UTF-16 string in native byte order.
2375 int sqlite3_complete(const char *sql);
2376 int sqlite3_complete16(const void *sql);
2379 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2380 ** KEYWORDS: {busy-handler callback} {busy handler}
2381 ** METHOD: sqlite3
2383 ** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2384 ** that might be invoked with argument P whenever
2385 ** an attempt is made to access a database table associated with
2386 ** [database connection] D when another thread
2387 ** or process has the table locked.
2388 ** The sqlite3_busy_handler() interface is used to implement
2389 ** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2391 ** ^If the busy callback is NULL, then [SQLITE_BUSY]
2392 ** is returned immediately upon encountering the lock. ^If the busy callback
2393 ** is not NULL, then the callback might be invoked with two arguments.
2395 ** ^The first argument to the busy handler is a copy of the void* pointer which
2396 ** is the third argument to sqlite3_busy_handler(). ^The second argument to
2397 ** the busy handler callback is the number of times that the busy handler has
2398 ** been invoked previously for the same locking event. ^If the
2399 ** busy callback returns 0, then no additional attempts are made to
2400 ** access the database and [SQLITE_BUSY] is returned
2401 ** to the application.
2402 ** ^If the callback returns non-zero, then another attempt
2403 ** is made to access the database and the cycle repeats.
2405 ** The presence of a busy handler does not guarantee that it will be invoked
2406 ** when there is lock contention. ^If SQLite determines that invoking the busy
2407 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2408 ** to the application instead of invoking the
2409 ** busy handler.
2410 ** Consider a scenario where one process is holding a read lock that
2411 ** it is trying to promote to a reserved lock and
2412 ** a second process is holding a reserved lock that it is trying
2413 ** to promote to an exclusive lock. The first process cannot proceed
2414 ** because it is blocked by the second and the second process cannot
2415 ** proceed because it is blocked by the first. If both processes
2416 ** invoke the busy handlers, neither will make any progress. Therefore,
2417 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2418 ** will induce the first process to release its read lock and allow
2419 ** the second process to proceed.
2421 ** ^The default busy callback is NULL.
2423 ** ^(There can only be a single busy handler defined for each
2424 ** [database connection]. Setting a new busy handler clears any
2425 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
2426 ** or evaluating [PRAGMA busy_timeout=N] will change the
2427 ** busy handler and thus clear any previously set busy handler.
2429 ** The busy callback should not take any actions which modify the
2430 ** database connection that invoked the busy handler. In other words,
2431 ** the busy handler is not reentrant. Any such actions
2432 ** result in undefined behavior.
2434 ** A busy handler must not close the database connection
2435 ** or [prepared statement] that invoked the busy handler.
2437 int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
2440 ** CAPI3REF: Set A Busy Timeout
2441 ** METHOD: sqlite3
2443 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2444 ** for a specified amount of time when a table is locked. ^The handler
2445 ** will sleep multiple times until at least "ms" milliseconds of sleeping
2446 ** have accumulated. ^After at least "ms" milliseconds of sleeping,
2447 ** the handler returns 0 which causes [sqlite3_step()] to return
2448 ** [SQLITE_BUSY].
2450 ** ^Calling this routine with an argument less than or equal to zero
2451 ** turns off all busy handlers.
2453 ** ^(There can only be a single busy handler for a particular
2454 ** [database connection] at any given moment. If another busy handler
2455 ** was defined (using [sqlite3_busy_handler()]) prior to calling
2456 ** this routine, that other busy handler is cleared.)^
2458 ** See also: [PRAGMA busy_timeout]
2460 int sqlite3_busy_timeout(sqlite3*, int ms);
2463 ** CAPI3REF: Convenience Routines For Running Queries
2464 ** METHOD: sqlite3
2466 ** This is a legacy interface that is preserved for backwards compatibility.
2467 ** Use of this interface is not recommended.
2469 ** Definition: A <b>result table</b> is memory data structure created by the
2470 ** [sqlite3_get_table()] interface. A result table records the
2471 ** complete query results from one or more queries.
2473 ** The table conceptually has a number of rows and columns. But
2474 ** these numbers are not part of the result table itself. These
2475 ** numbers are obtained separately. Let N be the number of rows
2476 ** and M be the number of columns.
2478 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2479 ** There are (N+1)*M elements in the array. The first M pointers point
2480 ** to zero-terminated strings that contain the names of the columns.
2481 ** The remaining entries all point to query results. NULL values result
2482 ** in NULL pointers. All other values are in their UTF-8 zero-terminated
2483 ** string representation as returned by [sqlite3_column_text()].
2485 ** A result table might consist of one or more memory allocations.
2486 ** It is not safe to pass a result table directly to [sqlite3_free()].
2487 ** A result table should be deallocated using [sqlite3_free_table()].
2489 ** ^(As an example of the result table format, suppose a query result
2490 ** is as follows:
2492 ** <blockquote><pre>
2493 ** Name | Age
2494 ** -----------------------
2495 ** Alice | 43
2496 ** Bob | 28
2497 ** Cindy | 21
2498 ** </pre></blockquote>
2500 ** There are two column (M==2) and three rows (N==3). Thus the
2501 ** result table has 8 entries. Suppose the result table is stored
2502 ** in an array names azResult. Then azResult holds this content:
2504 ** <blockquote><pre>
2505 ** azResult&#91;0] = "Name";
2506 ** azResult&#91;1] = "Age";
2507 ** azResult&#91;2] = "Alice";
2508 ** azResult&#91;3] = "43";
2509 ** azResult&#91;4] = "Bob";
2510 ** azResult&#91;5] = "28";
2511 ** azResult&#91;6] = "Cindy";
2512 ** azResult&#91;7] = "21";
2513 ** </pre></blockquote>)^
2515 ** ^The sqlite3_get_table() function evaluates one or more
2516 ** semicolon-separated SQL statements in the zero-terminated UTF-8
2517 ** string of its 2nd parameter and returns a result table to the
2518 ** pointer given in its 3rd parameter.
2520 ** After the application has finished with the result from sqlite3_get_table(),
2521 ** it must pass the result table pointer to sqlite3_free_table() in order to
2522 ** release the memory that was malloced. Because of the way the
2523 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2524 ** function must not try to call [sqlite3_free()] directly. Only
2525 ** [sqlite3_free_table()] is able to release the memory properly and safely.
2527 ** The sqlite3_get_table() interface is implemented as a wrapper around
2528 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
2529 ** to any internal data structures of SQLite. It uses only the public
2530 ** interface defined here. As a consequence, errors that occur in the
2531 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2532 ** reflected in subsequent calls to [sqlite3_errcode()] or
2533 ** [sqlite3_errmsg()].
2535 int sqlite3_get_table(
2536 sqlite3 *db, /* An open database */
2537 const char *zSql, /* SQL to be evaluated */
2538 char ***pazResult, /* Results of the query */
2539 int *pnRow, /* Number of result rows written here */
2540 int *pnColumn, /* Number of result columns written here */
2541 char **pzErrmsg /* Error msg written here */
2543 void sqlite3_free_table(char **result);
2546 ** CAPI3REF: Formatted String Printing Functions
2548 ** These routines are work-alikes of the "printf()" family of functions
2549 ** from the standard C library.
2550 ** These routines understand most of the common formatting options from
2551 ** the standard library printf()
2552 ** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
2553 ** See the [built-in printf()] documentation for details.
2555 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2556 ** results into memory obtained from [sqlite3_malloc64()].
2557 ** The strings returned by these two routines should be
2558 ** released by [sqlite3_free()]. ^Both routines return a
2559 ** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
2560 ** memory to hold the resulting string.
2562 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2563 ** the standard C library. The result is written into the
2564 ** buffer supplied as the second parameter whose size is given by
2565 ** the first parameter. Note that the order of the
2566 ** first two parameters is reversed from snprintf().)^ This is an
2567 ** historical accident that cannot be fixed without breaking
2568 ** backwards compatibility. ^(Note also that sqlite3_snprintf()
2569 ** returns a pointer to its buffer instead of the number of
2570 ** characters actually written into the buffer.)^ We admit that
2571 ** the number of characters written would be a more useful return
2572 ** value but we cannot change the implementation of sqlite3_snprintf()
2573 ** now without breaking compatibility.
2575 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2576 ** guarantees that the buffer is always zero-terminated. ^The first
2577 ** parameter "n" is the total size of the buffer, including space for
2578 ** the zero terminator. So the longest string that can be completely
2579 ** written will be n-1 characters.
2581 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2583 ** See also: [built-in printf()], [printf() SQL function]
2585 char *sqlite3_mprintf(const char*,...);
2586 char *sqlite3_vmprintf(const char*, va_list);
2587 char *sqlite3_snprintf(int,char*,const char*, ...);
2588 char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2591 ** CAPI3REF: Memory Allocation Subsystem
2593 ** The SQLite core uses these three routines for all of its own
2594 ** internal memory allocation needs. "Core" in the previous sentence
2595 ** does not include operating-system specific VFS implementation. The
2596 ** Windows VFS uses native malloc() and free() for some operations.
2598 ** ^The sqlite3_malloc() routine returns a pointer to a block
2599 ** of memory at least N bytes in length, where N is the parameter.
2600 ** ^If sqlite3_malloc() is unable to obtain sufficient free
2601 ** memory, it returns a NULL pointer. ^If the parameter N to
2602 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2603 ** a NULL pointer.
2605 ** ^The sqlite3_malloc64(N) routine works just like
2606 ** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2607 ** of a signed 32-bit integer.
2609 ** ^Calling sqlite3_free() with a pointer previously returned
2610 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2611 ** that it might be reused. ^The sqlite3_free() routine is
2612 ** a no-op if is called with a NULL pointer. Passing a NULL pointer
2613 ** to sqlite3_free() is harmless. After being freed, memory
2614 ** should neither be read nor written. Even reading previously freed
2615 ** memory might result in a segmentation fault or other severe error.
2616 ** Memory corruption, a segmentation fault, or other severe error
2617 ** might result if sqlite3_free() is called with a non-NULL pointer that
2618 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2620 ** ^The sqlite3_realloc(X,N) interface attempts to resize a
2621 ** prior memory allocation X to be at least N bytes.
2622 ** ^If the X parameter to sqlite3_realloc(X,N)
2623 ** is a NULL pointer then its behavior is identical to calling
2624 ** sqlite3_malloc(N).
2625 ** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2626 ** negative then the behavior is exactly the same as calling
2627 ** sqlite3_free(X).
2628 ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2629 ** of at least N bytes in size or NULL if insufficient memory is available.
2630 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2631 ** of the prior allocation are copied into the beginning of buffer returned
2632 ** by sqlite3_realloc(X,N) and the prior allocation is freed.
2633 ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2634 ** prior allocation is not freed.
2636 ** ^The sqlite3_realloc64(X,N) interfaces works the same as
2637 ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2638 ** of a 32-bit signed integer.
2640 ** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2641 ** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2642 ** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2643 ** ^The value returned by sqlite3_msize(X) might be larger than the number
2644 ** of bytes requested when X was allocated. ^If X is a NULL pointer then
2645 ** sqlite3_msize(X) returns zero. If X points to something that is not
2646 ** the beginning of memory allocation, or if it points to a formerly
2647 ** valid memory allocation that has now been freed, then the behavior
2648 ** of sqlite3_msize(X) is undefined and possibly harmful.
2650 ** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2651 ** sqlite3_malloc64(), and sqlite3_realloc64()
2652 ** is always aligned to at least an 8 byte boundary, or to a
2653 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2654 ** option is used.
2656 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2657 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2658 ** implementation of these routines to be omitted. That capability
2659 ** is no longer provided. Only built-in memory allocators can be used.
2661 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2662 ** the system malloc() and free() directly when converting
2663 ** filenames between the UTF-8 encoding used by SQLite
2664 ** and whatever filename encoding is used by the particular Windows
2665 ** installation. Memory allocation errors were detected, but
2666 ** they were reported back as [SQLITE_CANTOPEN] or
2667 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2669 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2670 ** must be either NULL or else pointers obtained from a prior
2671 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2672 ** not yet been released.
2674 ** The application must not read or write any part of
2675 ** a block of memory after it has been released using
2676 ** [sqlite3_free()] or [sqlite3_realloc()].
2678 void *sqlite3_malloc(int);
2679 void *sqlite3_malloc64(sqlite3_uint64);
2680 void *sqlite3_realloc(void*, int);
2681 void *sqlite3_realloc64(void*, sqlite3_uint64);
2682 void sqlite3_free(void*);
2683 sqlite3_uint64 sqlite3_msize(void*);
2686 ** CAPI3REF: Memory Allocator Statistics
2688 ** SQLite provides these two interfaces for reporting on the status
2689 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2690 ** routines, which form the built-in memory allocation subsystem.
2692 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2693 ** of memory currently outstanding (malloced but not freed).
2694 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2695 ** value of [sqlite3_memory_used()] since the high-water mark
2696 ** was last reset. ^The values returned by [sqlite3_memory_used()] and
2697 ** [sqlite3_memory_highwater()] include any overhead
2698 ** added by SQLite in its implementation of [sqlite3_malloc()],
2699 ** but not overhead added by the any underlying system library
2700 ** routines that [sqlite3_malloc()] may call.
2702 ** ^The memory high-water mark is reset to the current value of
2703 ** [sqlite3_memory_used()] if and only if the parameter to
2704 ** [sqlite3_memory_highwater()] is true. ^The value returned
2705 ** by [sqlite3_memory_highwater(1)] is the high-water mark
2706 ** prior to the reset.
2708 sqlite3_int64 sqlite3_memory_used(void);
2709 sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2712 ** CAPI3REF: Pseudo-Random Number Generator
2714 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2715 ** select random [ROWID | ROWIDs] when inserting new records into a table that
2716 ** already uses the largest possible [ROWID]. The PRNG is also used for
2717 ** the build-in random() and randomblob() SQL functions. This interface allows
2718 ** applications to access the same PRNG for other purposes.
2720 ** ^A call to this routine stores N bytes of randomness into buffer P.
2721 ** ^The P parameter can be a NULL pointer.
2723 ** ^If this routine has not been previously called or if the previous
2724 ** call had N less than one or a NULL pointer for P, then the PRNG is
2725 ** seeded using randomness obtained from the xRandomness method of
2726 ** the default [sqlite3_vfs] object.
2727 ** ^If the previous call to this routine had an N of 1 or more and a
2728 ** non-NULL P then the pseudo-randomness is generated
2729 ** internally and without recourse to the [sqlite3_vfs] xRandomness
2730 ** method.
2732 void sqlite3_randomness(int N, void *P);
2735 ** CAPI3REF: Compile-Time Authorization Callbacks
2736 ** METHOD: sqlite3
2737 ** KEYWORDS: {authorizer callback}
2739 ** ^This routine registers an authorizer callback with a particular
2740 ** [database connection], supplied in the first argument.
2741 ** ^The authorizer callback is invoked as SQL statements are being compiled
2742 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2743 ** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
2744 ** and [sqlite3_prepare16_v3()]. ^At various
2745 ** points during the compilation process, as logic is being created
2746 ** to perform various actions, the authorizer callback is invoked to
2747 ** see if those actions are allowed. ^The authorizer callback should
2748 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2749 ** specific action but allow the SQL statement to continue to be
2750 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2751 ** rejected with an error. ^If the authorizer callback returns
2752 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2753 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2754 ** the authorizer will fail with an error message.
2756 ** When the callback returns [SQLITE_OK], that means the operation
2757 ** requested is ok. ^When the callback returns [SQLITE_DENY], the
2758 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2759 ** authorizer will fail with an error message explaining that
2760 ** access is denied.
2762 ** ^The first parameter to the authorizer callback is a copy of the third
2763 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2764 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2765 ** the particular action to be authorized. ^The third through sixth parameters
2766 ** to the callback are either NULL pointers or zero-terminated strings
2767 ** that contain additional details about the action to be authorized.
2768 ** Applications must always be prepared to encounter a NULL pointer in any
2769 ** of the third through the sixth parameters of the authorization callback.
2771 ** ^If the action code is [SQLITE_READ]
2772 ** and the callback returns [SQLITE_IGNORE] then the
2773 ** [prepared statement] statement is constructed to substitute
2774 ** a NULL value in place of the table column that would have
2775 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2776 ** return can be used to deny an untrusted user access to individual
2777 ** columns of a table.
2778 ** ^When a table is referenced by a [SELECT] but no column values are
2779 ** extracted from that table (for example in a query like
2780 ** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
2781 ** is invoked once for that table with a column name that is an empty string.
2782 ** ^If the action code is [SQLITE_DELETE] and the callback returns
2783 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2784 ** [truncate optimization] is disabled and all rows are deleted individually.
2786 ** An authorizer is used when [sqlite3_prepare | preparing]
2787 ** SQL statements from an untrusted source, to ensure that the SQL statements
2788 ** do not try to access data they are not allowed to see, or that they do not
2789 ** try to execute malicious statements that damage the database. For
2790 ** example, an application may allow a user to enter arbitrary
2791 ** SQL queries for evaluation by a database. But the application does
2792 ** not want the user to be able to make arbitrary changes to the
2793 ** database. An authorizer could then be put in place while the
2794 ** user-entered SQL is being [sqlite3_prepare | prepared] that
2795 ** disallows everything except [SELECT] statements.
2797 ** Applications that need to process SQL from untrusted sources
2798 ** might also consider lowering resource limits using [sqlite3_limit()]
2799 ** and limiting database size using the [max_page_count] [PRAGMA]
2800 ** in addition to using an authorizer.
2802 ** ^(Only a single authorizer can be in place on a database connection
2803 ** at a time. Each call to sqlite3_set_authorizer overrides the
2804 ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2805 ** The authorizer is disabled by default.
2807 ** The authorizer callback must not do anything that will modify
2808 ** the database connection that invoked the authorizer callback.
2809 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2810 ** database connections for the meaning of "modify" in this paragraph.
2812 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2813 ** statement might be re-prepared during [sqlite3_step()] due to a
2814 ** schema change. Hence, the application should ensure that the
2815 ** correct authorizer callback remains in place during the [sqlite3_step()].
2817 ** ^Note that the authorizer callback is invoked only during
2818 ** [sqlite3_prepare()] or its variants. Authorization is not
2819 ** performed during statement evaluation in [sqlite3_step()], unless
2820 ** as stated in the previous paragraph, sqlite3_step() invokes
2821 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2823 int sqlite3_set_authorizer(
2824 sqlite3*,
2825 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2826 void *pUserData
2830 ** CAPI3REF: Authorizer Return Codes
2832 ** The [sqlite3_set_authorizer | authorizer callback function] must
2833 ** return either [SQLITE_OK] or one of these two constants in order
2834 ** to signal SQLite whether or not the action is permitted. See the
2835 ** [sqlite3_set_authorizer | authorizer documentation] for additional
2836 ** information.
2838 ** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2839 ** returned from the [sqlite3_vtab_on_conflict()] interface.
2841 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */
2842 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
2845 ** CAPI3REF: Authorizer Action Codes
2847 ** The [sqlite3_set_authorizer()] interface registers a callback function
2848 ** that is invoked to authorize certain SQL statement actions. The
2849 ** second parameter to the callback is an integer code that specifies
2850 ** what action is being authorized. These are the integer action codes that
2851 ** the authorizer callback may be passed.
2853 ** These action code values signify what kind of operation is to be
2854 ** authorized. The 3rd and 4th parameters to the authorization
2855 ** callback function will be parameters or NULL depending on which of these
2856 ** codes is used as the second parameter. ^(The 5th parameter to the
2857 ** authorizer callback is the name of the database ("main", "temp",
2858 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2859 ** is the name of the inner-most trigger or view that is responsible for
2860 ** the access attempt or NULL if this access attempt is directly from
2861 ** top-level SQL code.
2863 /******************************************* 3rd ************ 4th ***********/
2864 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
2865 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
2866 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
2867 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
2868 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
2869 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
2870 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2871 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2872 #define SQLITE_DELETE 9 /* Table Name NULL */
2873 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2874 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2875 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2876 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2877 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2878 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2879 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2880 #define SQLITE_DROP_VIEW 17 /* View Name NULL */
2881 #define SQLITE_INSERT 18 /* Table Name NULL */
2882 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2883 #define SQLITE_READ 20 /* Table Name Column Name */
2884 #define SQLITE_SELECT 21 /* NULL NULL */
2885 #define SQLITE_TRANSACTION 22 /* Operation NULL */
2886 #define SQLITE_UPDATE 23 /* Table Name Column Name */
2887 #define SQLITE_ATTACH 24 /* Filename NULL */
2888 #define SQLITE_DETACH 25 /* Database Name NULL */
2889 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2890 #define SQLITE_REINDEX 27 /* Index Name NULL */
2891 #define SQLITE_ANALYZE 28 /* Table Name NULL */
2892 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2893 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2894 #define SQLITE_FUNCTION 31 /* NULL Function Name */
2895 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2896 #define SQLITE_COPY 0 /* No longer used */
2897 #define SQLITE_RECURSIVE 33 /* NULL NULL */
2900 ** CAPI3REF: Tracing And Profiling Functions
2901 ** METHOD: sqlite3
2903 ** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
2904 ** instead of the routines described here.
2906 ** These routines register callback functions that can be used for
2907 ** tracing and profiling the execution of SQL statements.
2909 ** ^The callback function registered by sqlite3_trace() is invoked at
2910 ** various times when an SQL statement is being run by [sqlite3_step()].
2911 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2912 ** SQL statement text as the statement first begins executing.
2913 ** ^(Additional sqlite3_trace() callbacks might occur
2914 ** as each triggered subprogram is entered. The callbacks for triggers
2915 ** contain a UTF-8 SQL comment that identifies the trigger.)^
2917 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2918 ** the length of [bound parameter] expansion in the output of sqlite3_trace().
2920 ** ^The callback function registered by sqlite3_profile() is invoked
2921 ** as each SQL statement finishes. ^The profile callback contains
2922 ** the original statement text and an estimate of wall-clock time
2923 ** of how long that statement took to run. ^The profile callback
2924 ** time is in units of nanoseconds, however the current implementation
2925 ** is only capable of millisecond resolution so the six least significant
2926 ** digits in the time are meaningless. Future versions of SQLite
2927 ** might provide greater resolution on the profiler callback. The
2928 ** sqlite3_profile() function is considered experimental and is
2929 ** subject to change in future versions of SQLite.
2931 SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
2932 void(*xTrace)(void*,const char*), void*);
2933 SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
2934 void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2937 ** CAPI3REF: SQL Trace Event Codes
2938 ** KEYWORDS: SQLITE_TRACE
2940 ** These constants identify classes of events that can be monitored
2941 ** using the [sqlite3_trace_v2()] tracing logic. The M argument
2942 ** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
2943 ** the following constants. ^The first argument to the trace callback
2944 ** is one of the following constants.
2946 ** New tracing constants may be added in future releases.
2948 ** ^A trace callback has four arguments: xCallback(T,C,P,X).
2949 ** ^The T argument is one of the integer type codes above.
2950 ** ^The C argument is a copy of the context pointer passed in as the
2951 ** fourth argument to [sqlite3_trace_v2()].
2952 ** The P and X arguments are pointers whose meanings depend on T.
2954 ** <dl>
2955 ** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
2956 ** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
2957 ** first begins running and possibly at other times during the
2958 ** execution of the prepared statement, such as at the start of each
2959 ** trigger subprogram. ^The P argument is a pointer to the
2960 ** [prepared statement]. ^The X argument is a pointer to a string which
2961 ** is the unexpanded SQL text of the prepared statement or an SQL comment
2962 ** that indicates the invocation of a trigger. ^The callback can compute
2963 ** the same text that would have been returned by the legacy [sqlite3_trace()]
2964 ** interface by using the X argument when X begins with "--" and invoking
2965 ** [sqlite3_expanded_sql(P)] otherwise.
2967 ** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
2968 ** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
2969 ** information as is provided by the [sqlite3_profile()] callback.
2970 ** ^The P argument is a pointer to the [prepared statement] and the
2971 ** X argument points to a 64-bit integer which is the estimated of
2972 ** the number of nanosecond that the prepared statement took to run.
2973 ** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
2975 ** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
2976 ** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
2977 ** statement generates a single row of result.
2978 ** ^The P argument is a pointer to the [prepared statement] and the
2979 ** X argument is unused.
2981 ** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
2982 ** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
2983 ** connection closes.
2984 ** ^The P argument is a pointer to the [database connection] object
2985 ** and the X argument is unused.
2986 ** </dl>
2988 #define SQLITE_TRACE_STMT 0x01
2989 #define SQLITE_TRACE_PROFILE 0x02
2990 #define SQLITE_TRACE_ROW 0x04
2991 #define SQLITE_TRACE_CLOSE 0x08
2994 ** CAPI3REF: SQL Trace Hook
2995 ** METHOD: sqlite3
2997 ** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
2998 ** function X against [database connection] D, using property mask M
2999 ** and context pointer P. ^If the X callback is
3000 ** NULL or if the M mask is zero, then tracing is disabled. The
3001 ** M argument should be the bitwise OR-ed combination of
3002 ** zero or more [SQLITE_TRACE] constants.
3004 ** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides
3005 ** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2().
3007 ** ^The X callback is invoked whenever any of the events identified by
3008 ** mask M occur. ^The integer return value from the callback is currently
3009 ** ignored, though this may change in future releases. Callback
3010 ** implementations should return zero to ensure future compatibility.
3012 ** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
3013 ** ^The T argument is one of the [SQLITE_TRACE]
3014 ** constants to indicate why the callback was invoked.
3015 ** ^The C argument is a copy of the context pointer.
3016 ** The P and X arguments are pointers whose meanings depend on T.
3018 ** The sqlite3_trace_v2() interface is intended to replace the legacy
3019 ** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
3020 ** are deprecated.
3022 int sqlite3_trace_v2(
3023 sqlite3*,
3024 unsigned uMask,
3025 int(*xCallback)(unsigned,void*,void*,void*),
3026 void *pCtx
3030 ** CAPI3REF: Query Progress Callbacks
3031 ** METHOD: sqlite3
3033 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
3034 ** function X to be invoked periodically during long running calls to
3035 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
3036 ** database connection D. An example use for this
3037 ** interface is to keep a GUI updated during a large query.
3039 ** ^The parameter P is passed through as the only parameter to the
3040 ** callback function X. ^The parameter N is the approximate number of
3041 ** [virtual machine instructions] that are evaluated between successive
3042 ** invocations of the callback X. ^If N is less than one then the progress
3043 ** handler is disabled.
3045 ** ^Only a single progress handler may be defined at one time per
3046 ** [database connection]; setting a new progress handler cancels the
3047 ** old one. ^Setting parameter X to NULL disables the progress handler.
3048 ** ^The progress handler is also disabled by setting N to a value less
3049 ** than 1.
3051 ** ^If the progress callback returns non-zero, the operation is
3052 ** interrupted. This feature can be used to implement a
3053 ** "Cancel" button on a GUI progress dialog box.
3055 ** The progress handler callback must not do anything that will modify
3056 ** the database connection that invoked the progress handler.
3057 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3058 ** database connections for the meaning of "modify" in this paragraph.
3061 void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
3064 ** CAPI3REF: Opening A New Database Connection
3065 ** CONSTRUCTOR: sqlite3
3067 ** ^These routines open an SQLite database file as specified by the
3068 ** filename argument. ^The filename argument is interpreted as UTF-8 for
3069 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
3070 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
3071 ** returned in *ppDb, even if an error occurs. The only exception is that
3072 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
3073 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
3074 ** object.)^ ^(If the database is opened (and/or created) successfully, then
3075 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
3076 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
3077 ** an English language description of the error following a failure of any
3078 ** of the sqlite3_open() routines.
3080 ** ^The default encoding will be UTF-8 for databases created using
3081 ** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases
3082 ** created using sqlite3_open16() will be UTF-16 in the native byte order.
3084 ** Whether or not an error occurs when it is opened, resources
3085 ** associated with the [database connection] handle should be released by
3086 ** passing it to [sqlite3_close()] when it is no longer required.
3088 ** The sqlite3_open_v2() interface works like sqlite3_open()
3089 ** except that it accepts two additional parameters for additional control
3090 ** over the new database connection. ^(The flags parameter to
3091 ** sqlite3_open_v2() can take one of
3092 ** the following three values, optionally combined with the
3093 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
3094 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
3096 ** <dl>
3097 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
3098 ** <dd>The database is opened in read-only mode. If the database does not
3099 ** already exist, an error is returned.</dd>)^
3101 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
3102 ** <dd>The database is opened for reading and writing if possible, or reading
3103 ** only if the file is write protected by the operating system. In either
3104 ** case the database must already exist, otherwise an error is returned.</dd>)^
3106 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
3107 ** <dd>The database is opened for reading and writing, and is created if
3108 ** it does not already exist. This is the behavior that is always used for
3109 ** sqlite3_open() and sqlite3_open16().</dd>)^
3110 ** </dl>
3112 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
3113 ** combinations shown above optionally combined with other
3114 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
3115 ** then the behavior is undefined.
3117 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
3118 ** opens in the multi-thread [threading mode] as long as the single-thread
3119 ** mode has not been set at compile-time or start-time. ^If the
3120 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
3121 ** in the serialized [threading mode] unless single-thread was
3122 ** previously selected at compile-time or start-time.
3123 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
3124 ** eligible to use [shared cache mode], regardless of whether or not shared
3125 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
3126 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
3127 ** participate in [shared cache mode] even if it is enabled.
3129 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
3130 ** [sqlite3_vfs] object that defines the operating system interface that
3131 ** the new database connection should use. ^If the fourth parameter is
3132 ** a NULL pointer then the default [sqlite3_vfs] object is used.
3134 ** ^If the filename is ":memory:", then a private, temporary in-memory database
3135 ** is created for the connection. ^This in-memory database will vanish when
3136 ** the database connection is closed. Future versions of SQLite might
3137 ** make use of additional special filenames that begin with the ":" character.
3138 ** It is recommended that when a database filename actually does begin with
3139 ** a ":" character you should prefix the filename with a pathname such as
3140 ** "./" to avoid ambiguity.
3142 ** ^If the filename is an empty string, then a private, temporary
3143 ** on-disk database will be created. ^This private database will be
3144 ** automatically deleted as soon as the database connection is closed.
3146 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
3148 ** ^If [URI filename] interpretation is enabled, and the filename argument
3149 ** begins with "file:", then the filename is interpreted as a URI. ^URI
3150 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
3151 ** set in the third argument to sqlite3_open_v2(), or if it has
3152 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
3153 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
3154 ** URI filename interpretation is turned off
3155 ** by default, but future releases of SQLite might enable URI filename
3156 ** interpretation by default. See "[URI filenames]" for additional
3157 ** information.
3159 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
3160 ** authority, then it must be either an empty string or the string
3161 ** "localhost". ^If the authority is not an empty string or "localhost", an
3162 ** error is returned to the caller. ^The fragment component of a URI, if
3163 ** present, is ignored.
3165 ** ^SQLite uses the path component of the URI as the name of the disk file
3166 ** which contains the database. ^If the path begins with a '/' character,
3167 ** then it is interpreted as an absolute path. ^If the path does not begin
3168 ** with a '/' (meaning that the authority section is omitted from the URI)
3169 ** then the path is interpreted as a relative path.
3170 ** ^(On windows, the first component of an absolute path
3171 ** is a drive specification (e.g. "C:").)^
3173 ** [[core URI query parameters]]
3174 ** The query component of a URI may contain parameters that are interpreted
3175 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
3176 ** SQLite and its built-in [VFSes] interpret the
3177 ** following query parameters:
3179 ** <ul>
3180 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
3181 ** a VFS object that provides the operating system interface that should
3182 ** be used to access the database file on disk. ^If this option is set to
3183 ** an empty string the default VFS object is used. ^Specifying an unknown
3184 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
3185 ** present, then the VFS specified by the option takes precedence over
3186 ** the value passed as the fourth parameter to sqlite3_open_v2().
3188 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
3189 ** "rwc", or "memory". Attempting to set it to any other value is
3190 ** an error)^.
3191 ** ^If "ro" is specified, then the database is opened for read-only
3192 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
3193 ** third argument to sqlite3_open_v2(). ^If the mode option is set to
3194 ** "rw", then the database is opened for read-write (but not create)
3195 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
3196 ** been set. ^Value "rwc" is equivalent to setting both
3197 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
3198 ** set to "memory" then a pure [in-memory database] that never reads
3199 ** or writes from disk is used. ^It is an error to specify a value for
3200 ** the mode parameter that is less restrictive than that specified by
3201 ** the flags passed in the third parameter to sqlite3_open_v2().
3203 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
3204 ** "private". ^Setting it to "shared" is equivalent to setting the
3205 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
3206 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
3207 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
3208 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
3209 ** a URI filename, its value overrides any behavior requested by setting
3210 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
3212 ** <li> <b>psow</b>: ^The psow parameter indicates whether or not the
3213 ** [powersafe overwrite] property does or does not apply to the
3214 ** storage media on which the database file resides.
3216 ** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
3217 ** which if set disables file locking in rollback journal modes. This
3218 ** is useful for accessing a database on a filesystem that does not
3219 ** support locking. Caution: Database corruption might result if two
3220 ** or more processes write to the same database and any one of those
3221 ** processes uses nolock=1.
3223 ** <li> <b>immutable</b>: ^The immutable parameter is a boolean query
3224 ** parameter that indicates that the database file is stored on
3225 ** read-only media. ^When immutable is set, SQLite assumes that the
3226 ** database file cannot be changed, even by a process with higher
3227 ** privilege, and so the database is opened read-only and all locking
3228 ** and change detection is disabled. Caution: Setting the immutable
3229 ** property on a database file that does in fact change can result
3230 ** in incorrect query results and/or [SQLITE_CORRUPT] errors.
3231 ** See also: [SQLITE_IOCAP_IMMUTABLE].
3233 ** </ul>
3235 ** ^Specifying an unknown parameter in the query component of a URI is not an
3236 ** error. Future versions of SQLite might understand additional query
3237 ** parameters. See "[query parameters with special meaning to SQLite]" for
3238 ** additional information.
3240 ** [[URI filename examples]] <h3>URI filename examples</h3>
3242 ** <table border="1" align=center cellpadding=5>
3243 ** <tr><th> URI filenames <th> Results
3244 ** <tr><td> file:data.db <td>
3245 ** Open the file "data.db" in the current directory.
3246 ** <tr><td> file:/home/fred/data.db<br>
3247 ** file:///home/fred/data.db <br>
3248 ** file://localhost/home/fred/data.db <br> <td>
3249 ** Open the database file "/home/fred/data.db".
3250 ** <tr><td> file://darkstar/home/fred/data.db <td>
3251 ** An error. "darkstar" is not a recognized authority.
3252 ** <tr><td style="white-space:nowrap">
3253 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
3254 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive
3255 ** C:. Note that the %20 escaping in this example is not strictly
3256 ** necessary - space characters can be used literally
3257 ** in URI filenames.
3258 ** <tr><td> file:data.db?mode=ro&cache=private <td>
3259 ** Open file "data.db" in the current directory for read-only access.
3260 ** Regardless of whether or not shared-cache mode is enabled by
3261 ** default, use a private cache.
3262 ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
3263 ** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
3264 ** that uses dot-files in place of posix advisory locking.
3265 ** <tr><td> file:data.db?mode=readonly <td>
3266 ** An error. "readonly" is not a valid option for the "mode" parameter.
3267 ** </table>
3269 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
3270 ** query components of a URI. A hexadecimal escape sequence consists of a
3271 ** percent sign - "%" - followed by exactly two hexadecimal digits
3272 ** specifying an octet value. ^Before the path or query components of a
3273 ** URI filename are interpreted, they are encoded using UTF-8 and all
3274 ** hexadecimal escape sequences replaced by a single byte containing the
3275 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
3276 ** the results are undefined.
3278 ** <b>Note to Windows users:</b> The encoding used for the filename argument
3279 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
3280 ** codepage is currently defined. Filenames containing international
3281 ** characters must be converted to UTF-8 prior to passing them into
3282 ** sqlite3_open() or sqlite3_open_v2().
3284 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
3285 ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
3286 ** features that require the use of temporary files may fail.
3288 ** See also: [sqlite3_temp_directory]
3290 int sqlite3_open(
3291 const char *filename, /* Database filename (UTF-8) */
3292 sqlite3 **ppDb /* OUT: SQLite db handle */
3294 int sqlite3_open16(
3295 const void *filename, /* Database filename (UTF-16) */
3296 sqlite3 **ppDb /* OUT: SQLite db handle */
3298 int sqlite3_open_v2(
3299 const char *filename, /* Database filename (UTF-8) */
3300 sqlite3 **ppDb, /* OUT: SQLite db handle */
3301 int flags, /* Flags */
3302 const char *zVfs /* Name of VFS module to use */
3306 ** CAPI3REF: Obtain Values For URI Parameters
3308 ** These are utility routines, useful to VFS implementations, that check
3309 ** to see if a database file was a URI that contained a specific query
3310 ** parameter, and if so obtains the value of that query parameter.
3312 ** If F is the database filename pointer passed into the xOpen() method of
3313 ** a VFS implementation when the flags parameter to xOpen() has one or
3314 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
3315 ** P is the name of the query parameter, then
3316 ** sqlite3_uri_parameter(F,P) returns the value of the P
3317 ** parameter if it exists or a NULL pointer if P does not appear as a
3318 ** query parameter on F. If P is a query parameter of F
3319 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3320 ** a pointer to an empty string.
3322 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3323 ** parameter and returns true (1) or false (0) according to the value
3324 ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3325 ** value of query parameter P is one of "yes", "true", or "on" in any
3326 ** case or if the value begins with a non-zero number. The
3327 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3328 ** query parameter P is one of "no", "false", or "off" in any case or
3329 ** if the value begins with a numeric zero. If P is not a query
3330 ** parameter on F or if the value of P is does not match any of the
3331 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3333 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3334 ** 64-bit signed integer and returns that integer, or D if P does not
3335 ** exist. If the value of P is something other than an integer, then
3336 ** zero is returned.
3338 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3339 ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
3340 ** is not a database file pathname pointer that SQLite passed into the xOpen
3341 ** VFS method, then the behavior of this routine is undefined and probably
3342 ** undesirable.
3344 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3345 int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3346 sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3350 ** CAPI3REF: Error Codes And Messages
3351 ** METHOD: sqlite3
3353 ** ^If the most recent sqlite3_* API call associated with
3354 ** [database connection] D failed, then the sqlite3_errcode(D) interface
3355 ** returns the numeric [result code] or [extended result code] for that
3356 ** API call.
3357 ** If the most recent API call was successful,
3358 ** then the return value from sqlite3_errcode() is undefined.
3359 ** ^The sqlite3_extended_errcode()
3360 ** interface is the same except that it always returns the
3361 ** [extended result code] even when extended result codes are
3362 ** disabled.
3364 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3365 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
3366 ** ^(Memory to hold the error message string is managed internally.
3367 ** The application does not need to worry about freeing the result.
3368 ** However, the error string might be overwritten or deallocated by
3369 ** subsequent calls to other SQLite interface functions.)^
3371 ** ^The sqlite3_errstr() interface returns the English-language text
3372 ** that describes the [result code], as UTF-8.
3373 ** ^(Memory to hold the error message string is managed internally
3374 ** and must not be freed by the application)^.
3376 ** When the serialized [threading mode] is in use, it might be the
3377 ** case that a second error occurs on a separate thread in between
3378 ** the time of the first error and the call to these interfaces.
3379 ** When that happens, the second error will be reported since these
3380 ** interfaces always report the most recent result. To avoid
3381 ** this, each thread can obtain exclusive use of the [database connection] D
3382 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3383 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3384 ** all calls to the interfaces listed here are completed.
3386 ** If an interface fails with SQLITE_MISUSE, that means the interface
3387 ** was invoked incorrectly by the application. In that case, the
3388 ** error code and message may or may not be set.
3390 int sqlite3_errcode(sqlite3 *db);
3391 int sqlite3_extended_errcode(sqlite3 *db);
3392 const char *sqlite3_errmsg(sqlite3*);
3393 const void *sqlite3_errmsg16(sqlite3*);
3394 const char *sqlite3_errstr(int);
3397 ** CAPI3REF: Prepared Statement Object
3398 ** KEYWORDS: {prepared statement} {prepared statements}
3400 ** An instance of this object represents a single SQL statement that
3401 ** has been compiled into binary form and is ready to be evaluated.
3403 ** Think of each SQL statement as a separate computer program. The
3404 ** original SQL text is source code. A prepared statement object
3405 ** is the compiled object code. All SQL must be converted into a
3406 ** prepared statement before it can be run.
3408 ** The life-cycle of a prepared statement object usually goes like this:
3410 ** <ol>
3411 ** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
3412 ** <li> Bind values to [parameters] using the sqlite3_bind_*()
3413 ** interfaces.
3414 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3415 ** <li> Reset the prepared statement using [sqlite3_reset()] then go back
3416 ** to step 2. Do this zero or more times.
3417 ** <li> Destroy the object using [sqlite3_finalize()].
3418 ** </ol>
3420 typedef struct sqlite3_stmt sqlite3_stmt;
3423 ** CAPI3REF: Run-time Limits
3424 ** METHOD: sqlite3
3426 ** ^(This interface allows the size of various constructs to be limited
3427 ** on a connection by connection basis. The first parameter is the
3428 ** [database connection] whose limit is to be set or queried. The
3429 ** second parameter is one of the [limit categories] that define a
3430 ** class of constructs to be size limited. The third parameter is the
3431 ** new limit for that construct.)^
3433 ** ^If the new limit is a negative number, the limit is unchanged.
3434 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3435 ** [limits | hard upper bound]
3436 ** set at compile-time by a C preprocessor macro called
3437 ** [limits | SQLITE_MAX_<i>NAME</i>].
3438 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3439 ** ^Attempts to increase a limit above its hard upper bound are
3440 ** silently truncated to the hard upper bound.
3442 ** ^Regardless of whether or not the limit was changed, the
3443 ** [sqlite3_limit()] interface returns the prior value of the limit.
3444 ** ^Hence, to find the current value of a limit without changing it,
3445 ** simply invoke this interface with the third parameter set to -1.
3447 ** Run-time limits are intended for use in applications that manage
3448 ** both their own internal database and also databases that are controlled
3449 ** by untrusted external sources. An example application might be a
3450 ** web browser that has its own databases for storing history and
3451 ** separate databases controlled by JavaScript applications downloaded
3452 ** off the Internet. The internal databases can be given the
3453 ** large, default limits. Databases managed by external sources can
3454 ** be given much smaller limits designed to prevent a denial of service
3455 ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
3456 ** interface to further control untrusted SQL. The size of the database
3457 ** created by an untrusted script can be contained using the
3458 ** [max_page_count] [PRAGMA].
3460 ** New run-time limit categories may be added in future releases.
3462 int sqlite3_limit(sqlite3*, int id, int newVal);
3465 ** CAPI3REF: Run-Time Limit Categories
3466 ** KEYWORDS: {limit category} {*limit categories}
3468 ** These constants define various performance limits
3469 ** that can be lowered at run-time using [sqlite3_limit()].
3470 ** The synopsis of the meanings of the various limits is shown below.
3471 ** Additional information is available at [limits | Limits in SQLite].
3473 ** <dl>
3474 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3475 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3477 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3478 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3480 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3481 ** <dd>The maximum number of columns in a table definition or in the
3482 ** result set of a [SELECT] or the maximum number of columns in an index
3483 ** or in an ORDER BY or GROUP BY clause.</dd>)^
3485 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3486 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3488 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3489 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3491 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3492 ** <dd>The maximum number of instructions in a virtual machine program
3493 ** used to implement an SQL statement. If [sqlite3_prepare_v2()] or
3494 ** the equivalent tries to allocate space for more than this many opcodes
3495 ** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
3497 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3498 ** <dd>The maximum number of arguments on a function.</dd>)^
3500 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3501 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3503 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3504 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3505 ** <dd>The maximum length of the pattern argument to the [LIKE] or
3506 ** [GLOB] operators.</dd>)^
3508 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3509 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3510 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3512 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3513 ** <dd>The maximum depth of recursion for triggers.</dd>)^
3515 ** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
3516 ** <dd>The maximum number of auxiliary worker threads that a single
3517 ** [prepared statement] may start.</dd>)^
3518 ** </dl>
3520 #define SQLITE_LIMIT_LENGTH 0
3521 #define SQLITE_LIMIT_SQL_LENGTH 1
3522 #define SQLITE_LIMIT_COLUMN 2
3523 #define SQLITE_LIMIT_EXPR_DEPTH 3
3524 #define SQLITE_LIMIT_COMPOUND_SELECT 4
3525 #define SQLITE_LIMIT_VDBE_OP 5
3526 #define SQLITE_LIMIT_FUNCTION_ARG 6
3527 #define SQLITE_LIMIT_ATTACHED 7
3528 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
3529 #define SQLITE_LIMIT_VARIABLE_NUMBER 9
3530 #define SQLITE_LIMIT_TRIGGER_DEPTH 10
3531 #define SQLITE_LIMIT_WORKER_THREADS 11
3534 ** CAPI3REF: Prepare Flags
3536 ** These constants define various flags that can be passed into
3537 ** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
3538 ** [sqlite3_prepare16_v3()] interfaces.
3540 ** New flags may be added in future releases of SQLite.
3542 ** <dl>
3543 ** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
3544 ** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
3545 ** that the prepared statement will be retained for a long time and
3546 ** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
3547 ** and [sqlite3_prepare16_v3()] assume that the prepared statement will
3548 ** be used just once or at most a few times and then destroyed using
3549 ** [sqlite3_finalize()] relatively soon. The current implementation acts
3550 ** on this hint by avoiding the use of [lookaside memory] so as not to
3551 ** deplete the limited store of lookaside memory. Future versions of
3552 ** SQLite may act on this hint differently.
3553 ** </dl>
3555 #define SQLITE_PREPARE_PERSISTENT 0x01
3558 ** CAPI3REF: Compiling An SQL Statement
3559 ** KEYWORDS: {SQL statement compiler}
3560 ** METHOD: sqlite3
3561 ** CONSTRUCTOR: sqlite3_stmt
3563 ** To execute an SQL statement, it must first be compiled into a byte-code
3564 ** program using one of these routines. Or, in other words, these routines
3565 ** are constructors for the [prepared statement] object.
3567 ** The preferred routine to use is [sqlite3_prepare_v2()]. The
3568 ** [sqlite3_prepare()] interface is legacy and should be avoided.
3569 ** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
3570 ** for special purposes.
3572 ** The use of the UTF-8 interfaces is preferred, as SQLite currently
3573 ** does all parsing using UTF-8. The UTF-16 interfaces are provided
3574 ** as a convenience. The UTF-16 interfaces work by converting the
3575 ** input text into UTF-8, then invoking the corresponding UTF-8 interface.
3577 ** The first argument, "db", is a [database connection] obtained from a
3578 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3579 ** [sqlite3_open16()]. The database connection must not have been closed.
3581 ** The second argument, "zSql", is the statement to be compiled, encoded
3582 ** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(),
3583 ** and sqlite3_prepare_v3()
3584 ** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
3585 ** and sqlite3_prepare16_v3() use UTF-16.
3587 ** ^If the nByte argument is negative, then zSql is read up to the
3588 ** first zero terminator. ^If nByte is positive, then it is the
3589 ** number of bytes read from zSql. ^If nByte is zero, then no prepared
3590 ** statement is generated.
3591 ** If the caller knows that the supplied string is nul-terminated, then
3592 ** there is a small performance advantage to passing an nByte parameter that
3593 ** is the number of bytes in the input string <i>including</i>
3594 ** the nul-terminator.
3596 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3597 ** past the end of the first SQL statement in zSql. These routines only
3598 ** compile the first statement in zSql, so *pzTail is left pointing to
3599 ** what remains uncompiled.
3601 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3602 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
3603 ** to NULL. ^If the input text contains no SQL (if the input is an empty
3604 ** string or a comment) then *ppStmt is set to NULL.
3605 ** The calling procedure is responsible for deleting the compiled
3606 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
3607 ** ppStmt may not be NULL.
3609 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3610 ** otherwise an [error code] is returned.
3612 ** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
3613 ** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
3614 ** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
3615 ** are retained for backwards compatibility, but their use is discouraged.
3616 ** ^In the "vX" interfaces, the prepared statement
3617 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
3618 ** original SQL text. This causes the [sqlite3_step()] interface to
3619 ** behave differently in three ways:
3621 ** <ol>
3622 ** <li>
3623 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3624 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
3625 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3626 ** retries will occur before sqlite3_step() gives up and returns an error.
3627 ** </li>
3629 ** <li>
3630 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3631 ** [error codes] or [extended error codes]. ^The legacy behavior was that
3632 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3633 ** and the application would have to make a second call to [sqlite3_reset()]
3634 ** in order to find the underlying cause of the problem. With the "v2" prepare
3635 ** interfaces, the underlying reason for the error is returned immediately.
3636 ** </li>
3638 ** <li>
3639 ** ^If the specific value bound to [parameter | host parameter] in the
3640 ** WHERE clause might influence the choice of query plan for a statement,
3641 ** then the statement will be automatically recompiled, as if there had been
3642 ** a schema change, on the first [sqlite3_step()] call following any change
3643 ** to the [sqlite3_bind_text | bindings] of that [parameter].
3644 ** ^The specific value of WHERE-clause [parameter] might influence the
3645 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
3646 ** or [GLOB] operator or if the parameter is compared to an indexed column
3647 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3648 ** </li>
3649 ** </ol>
3651 ** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
3652 ** the extra prepFlags parameter, which is a bit array consisting of zero or
3653 ** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The
3654 ** sqlite3_prepare_v2() interface works exactly the same as
3655 ** sqlite3_prepare_v3() with a zero prepFlags parameter.
3657 int sqlite3_prepare(
3658 sqlite3 *db, /* Database handle */
3659 const char *zSql, /* SQL statement, UTF-8 encoded */
3660 int nByte, /* Maximum length of zSql in bytes. */
3661 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3662 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3664 int sqlite3_prepare_v2(
3665 sqlite3 *db, /* Database handle */
3666 const char *zSql, /* SQL statement, UTF-8 encoded */
3667 int nByte, /* Maximum length of zSql in bytes. */
3668 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3669 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3671 int sqlite3_prepare_v3(
3672 sqlite3 *db, /* Database handle */
3673 const char *zSql, /* SQL statement, UTF-8 encoded */
3674 int nByte, /* Maximum length of zSql in bytes. */
3675 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
3676 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3677 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3679 int sqlite3_prepare16(
3680 sqlite3 *db, /* Database handle */
3681 const void *zSql, /* SQL statement, UTF-16 encoded */
3682 int nByte, /* Maximum length of zSql in bytes. */
3683 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3684 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3686 int sqlite3_prepare16_v2(
3687 sqlite3 *db, /* Database handle */
3688 const void *zSql, /* SQL statement, UTF-16 encoded */
3689 int nByte, /* Maximum length of zSql in bytes. */
3690 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3691 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3693 int sqlite3_prepare16_v3(
3694 sqlite3 *db, /* Database handle */
3695 const void *zSql, /* SQL statement, UTF-16 encoded */
3696 int nByte, /* Maximum length of zSql in bytes. */
3697 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
3698 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3699 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3703 ** CAPI3REF: Retrieving Statement SQL
3704 ** METHOD: sqlite3_stmt
3706 ** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
3707 ** SQL text used to create [prepared statement] P if P was
3708 ** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
3709 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
3710 ** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
3711 ** string containing the SQL text of prepared statement P with
3712 ** [bound parameters] expanded.
3714 ** ^(For example, if a prepared statement is created using the SQL
3715 ** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
3716 ** and parameter :xyz is unbound, then sqlite3_sql() will return
3717 ** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
3718 ** will return "SELECT 2345,NULL".)^
3720 ** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
3721 ** is available to hold the result, or if the result would exceed the
3722 ** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
3724 ** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
3725 ** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time
3726 ** option causes sqlite3_expanded_sql() to always return NULL.
3728 ** ^The string returned by sqlite3_sql(P) is managed by SQLite and is
3729 ** automatically freed when the prepared statement is finalized.
3730 ** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
3731 ** is obtained from [sqlite3_malloc()] and must be free by the application
3732 ** by passing it to [sqlite3_free()].
3734 const char *sqlite3_sql(sqlite3_stmt *pStmt);
3735 char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
3738 ** CAPI3REF: Determine If An SQL Statement Writes The Database
3739 ** METHOD: sqlite3_stmt
3741 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3742 ** and only if the [prepared statement] X makes no direct changes to
3743 ** the content of the database file.
3745 ** Note that [application-defined SQL functions] or
3746 ** [virtual tables] might change the database indirectly as a side effect.
3747 ** ^(For example, if an application defines a function "eval()" that
3748 ** calls [sqlite3_exec()], then the following SQL statement would
3749 ** change the database file through side-effects:
3751 ** <blockquote><pre>
3752 ** SELECT eval('DELETE FROM t1') FROM t2;
3753 ** </pre></blockquote>
3755 ** But because the [SELECT] statement does not change the database file
3756 ** directly, sqlite3_stmt_readonly() would still return true.)^
3758 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3759 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3760 ** since the statements themselves do not actually modify the database but
3761 ** rather they control the timing of when other statements modify the
3762 ** database. ^The [ATTACH] and [DETACH] statements also cause
3763 ** sqlite3_stmt_readonly() to return true since, while those statements
3764 ** change the configuration of a database connection, they do not make
3765 ** changes to the content of the database files on disk.
3766 ** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
3767 ** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
3768 ** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
3769 ** sqlite3_stmt_readonly() returns false for those commands.
3771 int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3774 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3775 ** METHOD: sqlite3_stmt
3777 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3778 ** [prepared statement] S has been stepped at least once using
3779 ** [sqlite3_step(S)] but has neither run to completion (returned
3780 ** [SQLITE_DONE] from [sqlite3_step(S)]) nor
3781 ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
3782 ** interface returns false if S is a NULL pointer. If S is not a
3783 ** NULL pointer and is not a pointer to a valid [prepared statement]
3784 ** object, then the behavior is undefined and probably undesirable.
3786 ** This interface can be used in combination [sqlite3_next_stmt()]
3787 ** to locate all prepared statements associated with a database
3788 ** connection that are in need of being reset. This can be used,
3789 ** for example, in diagnostic routines to search for prepared
3790 ** statements that are holding a transaction open.
3792 int sqlite3_stmt_busy(sqlite3_stmt*);
3795 ** CAPI3REF: Dynamically Typed Value Object
3796 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3798 ** SQLite uses the sqlite3_value object to represent all values
3799 ** that can be stored in a database table. SQLite uses dynamic typing
3800 ** for the values it stores. ^Values stored in sqlite3_value objects
3801 ** can be integers, floating point values, strings, BLOBs, or NULL.
3803 ** An sqlite3_value object may be either "protected" or "unprotected".
3804 ** Some interfaces require a protected sqlite3_value. Other interfaces
3805 ** will accept either a protected or an unprotected sqlite3_value.
3806 ** Every interface that accepts sqlite3_value arguments specifies
3807 ** whether or not it requires a protected sqlite3_value. The
3808 ** [sqlite3_value_dup()] interface can be used to construct a new
3809 ** protected sqlite3_value from an unprotected sqlite3_value.
3811 ** The terms "protected" and "unprotected" refer to whether or not
3812 ** a mutex is held. An internal mutex is held for a protected
3813 ** sqlite3_value object but no mutex is held for an unprotected
3814 ** sqlite3_value object. If SQLite is compiled to be single-threaded
3815 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3816 ** or if SQLite is run in one of reduced mutex modes
3817 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3818 ** then there is no distinction between protected and unprotected
3819 ** sqlite3_value objects and they can be used interchangeably. However,
3820 ** for maximum code portability it is recommended that applications
3821 ** still make the distinction between protected and unprotected
3822 ** sqlite3_value objects even when not strictly required.
3824 ** ^The sqlite3_value objects that are passed as parameters into the
3825 ** implementation of [application-defined SQL functions] are protected.
3826 ** ^The sqlite3_value object returned by
3827 ** [sqlite3_column_value()] is unprotected.
3828 ** Unprotected sqlite3_value objects may only be used as arguments
3829 ** to [sqlite3_result_value()], [sqlite3_bind_value()], and
3830 ** [sqlite3_value_dup()].
3831 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
3832 ** interfaces require protected sqlite3_value objects.
3834 typedef struct sqlite3_value sqlite3_value;
3837 ** CAPI3REF: SQL Function Context Object
3839 ** The context in which an SQL function executes is stored in an
3840 ** sqlite3_context object. ^A pointer to an sqlite3_context object
3841 ** is always first parameter to [application-defined SQL functions].
3842 ** The application-defined SQL function implementation will pass this
3843 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3844 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3845 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3846 ** and/or [sqlite3_set_auxdata()].
3848 typedef struct sqlite3_context sqlite3_context;
3851 ** CAPI3REF: Binding Values To Prepared Statements
3852 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3853 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3854 ** METHOD: sqlite3_stmt
3856 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3857 ** literals may be replaced by a [parameter] that matches one of following
3858 ** templates:
3860 ** <ul>
3861 ** <li> ?
3862 ** <li> ?NNN
3863 ** <li> :VVV
3864 ** <li> @VVV
3865 ** <li> $VVV
3866 ** </ul>
3868 ** In the templates above, NNN represents an integer literal,
3869 ** and VVV represents an alphanumeric identifier.)^ ^The values of these
3870 ** parameters (also called "host parameter names" or "SQL parameters")
3871 ** can be set using the sqlite3_bind_*() routines defined here.
3873 ** ^The first argument to the sqlite3_bind_*() routines is always
3874 ** a pointer to the [sqlite3_stmt] object returned from
3875 ** [sqlite3_prepare_v2()] or its variants.
3877 ** ^The second argument is the index of the SQL parameter to be set.
3878 ** ^The leftmost SQL parameter has an index of 1. ^When the same named
3879 ** SQL parameter is used more than once, second and subsequent
3880 ** occurrences have the same index as the first occurrence.
3881 ** ^The index for named parameters can be looked up using the
3882 ** [sqlite3_bind_parameter_index()] API if desired. ^The index
3883 ** for "?NNN" parameters is the value of NNN.
3884 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
3885 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3887 ** ^The third argument is the value to bind to the parameter.
3888 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3889 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3890 ** is ignored and the end result is the same as sqlite3_bind_null().
3892 ** ^(In those routines that have a fourth argument, its value is the
3893 ** number of bytes in the parameter. To be clear: the value is the
3894 ** number of <u>bytes</u> in the value, not the number of characters.)^
3895 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3896 ** is negative, then the length of the string is
3897 ** the number of bytes up to the first zero terminator.
3898 ** If the fourth parameter to sqlite3_bind_blob() is negative, then
3899 ** the behavior is undefined.
3900 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3901 ** or sqlite3_bind_text16() or sqlite3_bind_text64() then
3902 ** that parameter must be the byte offset
3903 ** where the NUL terminator would occur assuming the string were NUL
3904 ** terminated. If any NUL characters occur at byte offsets less than
3905 ** the value of the fourth parameter then the resulting string value will
3906 ** contain embedded NULs. The result of expressions involving strings
3907 ** with embedded NULs is undefined.
3909 ** ^The fifth argument to the BLOB and string binding interfaces
3910 ** is a destructor used to dispose of the BLOB or
3911 ** string after SQLite has finished with it. ^The destructor is called
3912 ** to dispose of the BLOB or string even if the call to bind API fails.
3913 ** ^If the fifth argument is
3914 ** the special value [SQLITE_STATIC], then SQLite assumes that the
3915 ** information is in static, unmanaged space and does not need to be freed.
3916 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3917 ** SQLite makes its own private copy of the data immediately, before
3918 ** the sqlite3_bind_*() routine returns.
3920 ** ^The sixth argument to sqlite3_bind_text64() must be one of
3921 ** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
3922 ** to specify the encoding of the text in the third parameter. If
3923 ** the sixth argument to sqlite3_bind_text64() is not one of the
3924 ** allowed values shown above, or if the text encoding is different
3925 ** from the encoding specified by the sixth parameter, then the behavior
3926 ** is undefined.
3928 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3929 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
3930 ** (just an integer to hold its size) while it is being processed.
3931 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
3932 ** content is later written using
3933 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
3934 ** ^A negative value for the zeroblob results in a zero-length BLOB.
3936 ** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
3937 ** [prepared statement] S to have an SQL value of NULL, but to also be
3938 ** associated with the pointer P of type T. ^D is either a NULL pointer or
3939 ** a pointer to a destructor function for P. ^SQLite will invoke the
3940 ** destructor D with a single argument of P when it is finished using
3941 ** P. The T parameter should be a static string, preferably a string
3942 ** literal. The sqlite3_bind_pointer() routine is part of the
3943 ** [pointer passing interface] added for SQLite 3.20.0.
3945 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3946 ** for the [prepared statement] or with a prepared statement for which
3947 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3948 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
3949 ** routine is passed a [prepared statement] that has been finalized, the
3950 ** result is undefined and probably harmful.
3952 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3953 ** ^Unbound parameters are interpreted as NULL.
3955 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3956 ** [error code] if anything goes wrong.
3957 ** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
3958 ** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
3959 ** [SQLITE_MAX_LENGTH].
3960 ** ^[SQLITE_RANGE] is returned if the parameter
3961 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
3963 ** See also: [sqlite3_bind_parameter_count()],
3964 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3966 int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3967 int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
3968 void(*)(void*));
3969 int sqlite3_bind_double(sqlite3_stmt*, int, double);
3970 int sqlite3_bind_int(sqlite3_stmt*, int, int);
3971 int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3972 int sqlite3_bind_null(sqlite3_stmt*, int);
3973 int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
3974 int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3975 int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
3976 void(*)(void*), unsigned char encoding);
3977 int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3978 int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
3979 int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3980 int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
3983 ** CAPI3REF: Number Of SQL Parameters
3984 ** METHOD: sqlite3_stmt
3986 ** ^This routine can be used to find the number of [SQL parameters]
3987 ** in a [prepared statement]. SQL parameters are tokens of the
3988 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3989 ** placeholders for values that are [sqlite3_bind_blob | bound]
3990 ** to the parameters at a later time.
3992 ** ^(This routine actually returns the index of the largest (rightmost)
3993 ** parameter. For all forms except ?NNN, this will correspond to the
3994 ** number of unique parameters. If parameters of the ?NNN form are used,
3995 ** there may be gaps in the list.)^
3997 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3998 ** [sqlite3_bind_parameter_name()], and
3999 ** [sqlite3_bind_parameter_index()].
4001 int sqlite3_bind_parameter_count(sqlite3_stmt*);
4004 ** CAPI3REF: Name Of A Host Parameter
4005 ** METHOD: sqlite3_stmt
4007 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
4008 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
4009 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
4010 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
4011 ** respectively.
4012 ** In other words, the initial ":" or "$" or "@" or "?"
4013 ** is included as part of the name.)^
4014 ** ^Parameters of the form "?" without a following integer have no name
4015 ** and are referred to as "nameless" or "anonymous parameters".
4017 ** ^The first host parameter has an index of 1, not 0.
4019 ** ^If the value N is out of range or if the N-th parameter is
4020 ** nameless, then NULL is returned. ^The returned string is
4021 ** always in UTF-8 encoding even if the named parameter was
4022 ** originally specified as UTF-16 in [sqlite3_prepare16()],
4023 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4025 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4026 ** [sqlite3_bind_parameter_count()], and
4027 ** [sqlite3_bind_parameter_index()].
4029 const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
4032 ** CAPI3REF: Index Of A Parameter With A Given Name
4033 ** METHOD: sqlite3_stmt
4035 ** ^Return the index of an SQL parameter given its name. ^The
4036 ** index value returned is suitable for use as the second
4037 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
4038 ** is returned if no matching parameter is found. ^The parameter
4039 ** name must be given in UTF-8 even if the original statement
4040 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
4041 ** [sqlite3_prepare16_v3()].
4043 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4044 ** [sqlite3_bind_parameter_count()], and
4045 ** [sqlite3_bind_parameter_name()].
4047 int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
4050 ** CAPI3REF: Reset All Bindings On A Prepared Statement
4051 ** METHOD: sqlite3_stmt
4053 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
4054 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
4055 ** ^Use this routine to reset all host parameters to NULL.
4057 int sqlite3_clear_bindings(sqlite3_stmt*);
4060 ** CAPI3REF: Number Of Columns In A Result Set
4061 ** METHOD: sqlite3_stmt
4063 ** ^Return the number of columns in the result set returned by the
4064 ** [prepared statement]. ^If this routine returns 0, that means the
4065 ** [prepared statement] returns no data (for example an [UPDATE]).
4066 ** ^However, just because this routine returns a positive number does not
4067 ** mean that one or more rows of data will be returned. ^A SELECT statement
4068 ** will always have a positive sqlite3_column_count() but depending on the
4069 ** WHERE clause constraints and the table content, it might return no rows.
4071 ** See also: [sqlite3_data_count()]
4073 int sqlite3_column_count(sqlite3_stmt *pStmt);
4076 ** CAPI3REF: Column Names In A Result Set
4077 ** METHOD: sqlite3_stmt
4079 ** ^These routines return the name assigned to a particular column
4080 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
4081 ** interface returns a pointer to a zero-terminated UTF-8 string
4082 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
4083 ** UTF-16 string. ^The first parameter is the [prepared statement]
4084 ** that implements the [SELECT] statement. ^The second parameter is the
4085 ** column number. ^The leftmost column is number 0.
4087 ** ^The returned string pointer is valid until either the [prepared statement]
4088 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
4089 ** reprepared by the first call to [sqlite3_step()] for a particular run
4090 ** or until the next call to
4091 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
4093 ** ^If sqlite3_malloc() fails during the processing of either routine
4094 ** (for example during a conversion from UTF-8 to UTF-16) then a
4095 ** NULL pointer is returned.
4097 ** ^The name of a result column is the value of the "AS" clause for
4098 ** that column, if there is an AS clause. If there is no AS clause
4099 ** then the name of the column is unspecified and may change from
4100 ** one release of SQLite to the next.
4102 const char *sqlite3_column_name(sqlite3_stmt*, int N);
4103 const void *sqlite3_column_name16(sqlite3_stmt*, int N);
4106 ** CAPI3REF: Source Of Data In A Query Result
4107 ** METHOD: sqlite3_stmt
4109 ** ^These routines provide a means to determine the database, table, and
4110 ** table column that is the origin of a particular result column in
4111 ** [SELECT] statement.
4112 ** ^The name of the database or table or column can be returned as
4113 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
4114 ** the database name, the _table_ routines return the table name, and
4115 ** the origin_ routines return the column name.
4116 ** ^The returned string is valid until the [prepared statement] is destroyed
4117 ** using [sqlite3_finalize()] or until the statement is automatically
4118 ** reprepared by the first call to [sqlite3_step()] for a particular run
4119 ** or until the same information is requested
4120 ** again in a different encoding.
4122 ** ^The names returned are the original un-aliased names of the
4123 ** database, table, and column.
4125 ** ^The first argument to these interfaces is a [prepared statement].
4126 ** ^These functions return information about the Nth result column returned by
4127 ** the statement, where N is the second function argument.
4128 ** ^The left-most column is column 0 for these routines.
4130 ** ^If the Nth column returned by the statement is an expression or
4131 ** subquery and is not a column value, then all of these functions return
4132 ** NULL. ^These routine might also return NULL if a memory allocation error
4133 ** occurs. ^Otherwise, they return the name of the attached database, table,
4134 ** or column that query result column was extracted from.
4136 ** ^As with all other SQLite APIs, those whose names end with "16" return
4137 ** UTF-16 encoded strings and the other functions return UTF-8.
4139 ** ^These APIs are only available if the library was compiled with the
4140 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
4142 ** If two or more threads call one or more of these routines against the same
4143 ** prepared statement and column at the same time then the results are
4144 ** undefined.
4146 ** If two or more threads call one or more
4147 ** [sqlite3_column_database_name | column metadata interfaces]
4148 ** for the same [prepared statement] and result column
4149 ** at the same time then the results are undefined.
4151 const char *sqlite3_column_database_name(sqlite3_stmt*,int);
4152 const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
4153 const char *sqlite3_column_table_name(sqlite3_stmt*,int);
4154 const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
4155 const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
4156 const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
4159 ** CAPI3REF: Declared Datatype Of A Query Result
4160 ** METHOD: sqlite3_stmt
4162 ** ^(The first parameter is a [prepared statement].
4163 ** If this statement is a [SELECT] statement and the Nth column of the
4164 ** returned result set of that [SELECT] is a table column (not an
4165 ** expression or subquery) then the declared type of the table
4166 ** column is returned.)^ ^If the Nth column of the result set is an
4167 ** expression or subquery, then a NULL pointer is returned.
4168 ** ^The returned string is always UTF-8 encoded.
4170 ** ^(For example, given the database schema:
4172 ** CREATE TABLE t1(c1 VARIANT);
4174 ** and the following statement to be compiled:
4176 ** SELECT c1 + 1, c1 FROM t1;
4178 ** this routine would return the string "VARIANT" for the second result
4179 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
4181 ** ^SQLite uses dynamic run-time typing. ^So just because a column
4182 ** is declared to contain a particular type does not mean that the
4183 ** data stored in that column is of the declared type. SQLite is
4184 ** strongly typed, but the typing is dynamic not static. ^Type
4185 ** is associated with individual values, not with the containers
4186 ** used to hold those values.
4188 const char *sqlite3_column_decltype(sqlite3_stmt*,int);
4189 const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
4192 ** CAPI3REF: Evaluate An SQL Statement
4193 ** METHOD: sqlite3_stmt
4195 ** After a [prepared statement] has been prepared using any of
4196 ** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
4197 ** or [sqlite3_prepare16_v3()] or one of the legacy
4198 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
4199 ** must be called one or more times to evaluate the statement.
4201 ** The details of the behavior of the sqlite3_step() interface depend
4202 ** on whether the statement was prepared using the newer "vX" interfaces
4203 ** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
4204 ** [sqlite3_prepare16_v2()] or the older legacy
4205 ** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
4206 ** new "vX" interface is recommended for new applications but the legacy
4207 ** interface will continue to be supported.
4209 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
4210 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
4211 ** ^With the "v2" interface, any of the other [result codes] or
4212 ** [extended result codes] might be returned as well.
4214 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
4215 ** database locks it needs to do its job. ^If the statement is a [COMMIT]
4216 ** or occurs outside of an explicit transaction, then you can retry the
4217 ** statement. If the statement is not a [COMMIT] and occurs within an
4218 ** explicit transaction then you should rollback the transaction before
4219 ** continuing.
4221 ** ^[SQLITE_DONE] means that the statement has finished executing
4222 ** successfully. sqlite3_step() should not be called again on this virtual
4223 ** machine without first calling [sqlite3_reset()] to reset the virtual
4224 ** machine back to its initial state.
4226 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
4227 ** is returned each time a new row of data is ready for processing by the
4228 ** caller. The values may be accessed using the [column access functions].
4229 ** sqlite3_step() is called again to retrieve the next row of data.
4231 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
4232 ** violation) has occurred. sqlite3_step() should not be called again on
4233 ** the VM. More information may be found by calling [sqlite3_errmsg()].
4234 ** ^With the legacy interface, a more specific error code (for example,
4235 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
4236 ** can be obtained by calling [sqlite3_reset()] on the
4237 ** [prepared statement]. ^In the "v2" interface,
4238 ** the more specific error code is returned directly by sqlite3_step().
4240 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
4241 ** Perhaps it was called on a [prepared statement] that has
4242 ** already been [sqlite3_finalize | finalized] or on one that had
4243 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
4244 ** be the case that the same database connection is being used by two or
4245 ** more threads at the same moment in time.
4247 ** For all versions of SQLite up to and including 3.6.23.1, a call to
4248 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
4249 ** other than [SQLITE_ROW] before any subsequent invocation of
4250 ** sqlite3_step(). Failure to reset the prepared statement using
4251 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
4252 ** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1],
4253 ** sqlite3_step() began
4254 ** calling [sqlite3_reset()] automatically in this circumstance rather
4255 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
4256 ** break because any application that ever receives an SQLITE_MISUSE error
4257 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
4258 ** can be used to restore the legacy behavior.
4260 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
4261 ** API always returns a generic error code, [SQLITE_ERROR], following any
4262 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
4263 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
4264 ** specific [error codes] that better describes the error.
4265 ** We admit that this is a goofy design. The problem has been fixed
4266 ** with the "v2" interface. If you prepare all of your SQL statements
4267 ** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
4268 ** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
4269 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
4270 ** then the more specific [error codes] are returned directly
4271 ** by sqlite3_step(). The use of the "vX" interfaces is recommended.
4273 int sqlite3_step(sqlite3_stmt*);
4276 ** CAPI3REF: Number of columns in a result set
4277 ** METHOD: sqlite3_stmt
4279 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
4280 ** current row of the result set of [prepared statement] P.
4281 ** ^If prepared statement P does not have results ready to return
4282 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
4283 ** interfaces) then sqlite3_data_count(P) returns 0.
4284 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
4285 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
4286 ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
4287 ** will return non-zero if previous call to [sqlite3_step](P) returned
4288 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
4289 ** where it always returns zero since each step of that multi-step
4290 ** pragma returns 0 columns of data.
4292 ** See also: [sqlite3_column_count()]
4294 int sqlite3_data_count(sqlite3_stmt *pStmt);
4297 ** CAPI3REF: Fundamental Datatypes
4298 ** KEYWORDS: SQLITE_TEXT
4300 ** ^(Every value in SQLite has one of five fundamental datatypes:
4302 ** <ul>
4303 ** <li> 64-bit signed integer
4304 ** <li> 64-bit IEEE floating point number
4305 ** <li> string
4306 ** <li> BLOB
4307 ** <li> NULL
4308 ** </ul>)^
4310 ** These constants are codes for each of those types.
4312 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
4313 ** for a completely different meaning. Software that links against both
4314 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
4315 ** SQLITE_TEXT.
4317 #define SQLITE_INTEGER 1
4318 #define SQLITE_FLOAT 2
4319 #define SQLITE_BLOB 4
4320 #define SQLITE_NULL 5
4321 #ifdef SQLITE_TEXT
4322 # undef SQLITE_TEXT
4323 #else
4324 # define SQLITE_TEXT 3
4325 #endif
4326 #define SQLITE3_TEXT 3
4329 ** CAPI3REF: Result Values From A Query
4330 ** KEYWORDS: {column access functions}
4331 ** METHOD: sqlite3_stmt
4333 ** <b>Summary:</b>
4334 ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
4335 ** <tr><td><b>sqlite3_column_blob</b><td>&rarr;<td>BLOB result
4336 ** <tr><td><b>sqlite3_column_double</b><td>&rarr;<td>REAL result
4337 ** <tr><td><b>sqlite3_column_int</b><td>&rarr;<td>32-bit INTEGER result
4338 ** <tr><td><b>sqlite3_column_int64</b><td>&rarr;<td>64-bit INTEGER result
4339 ** <tr><td><b>sqlite3_column_text</b><td>&rarr;<td>UTF-8 TEXT result
4340 ** <tr><td><b>sqlite3_column_text16</b><td>&rarr;<td>UTF-16 TEXT result
4341 ** <tr><td><b>sqlite3_column_value</b><td>&rarr;<td>The result as an
4342 ** [sqlite3_value|unprotected sqlite3_value] object.
4343 ** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
4344 ** <tr><td><b>sqlite3_column_bytes</b><td>&rarr;<td>Size of a BLOB
4345 ** or a UTF-8 TEXT result in bytes
4346 ** <tr><td><b>sqlite3_column_bytes16&nbsp;&nbsp;</b>
4347 ** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
4348 ** TEXT in bytes
4349 ** <tr><td><b>sqlite3_column_type</b><td>&rarr;<td>Default
4350 ** datatype of the result
4351 ** </table></blockquote>
4353 ** <b>Details:</b>
4355 ** ^These routines return information about a single column of the current
4356 ** result row of a query. ^In every case the first argument is a pointer
4357 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
4358 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
4359 ** and the second argument is the index of the column for which information
4360 ** should be returned. ^The leftmost column of the result set has the index 0.
4361 ** ^The number of columns in the result can be determined using
4362 ** [sqlite3_column_count()].
4364 ** If the SQL statement does not currently point to a valid row, or if the
4365 ** column index is out of range, the result is undefined.
4366 ** These routines may only be called when the most recent call to
4367 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
4368 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
4369 ** If any of these routines are called after [sqlite3_reset()] or
4370 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
4371 ** something other than [SQLITE_ROW], the results are undefined.
4372 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
4373 ** are called from a different thread while any of these routines
4374 ** are pending, then the results are undefined.
4376 ** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
4377 ** each return the value of a result column in a specific data format. If
4378 ** the result column is not initially in the requested format (for example,
4379 ** if the query returns an integer but the sqlite3_column_text() interface
4380 ** is used to extract the value) then an automatic type conversion is performed.
4382 ** ^The sqlite3_column_type() routine returns the
4383 ** [SQLITE_INTEGER | datatype code] for the initial data type
4384 ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
4385 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
4386 ** The return value of sqlite3_column_type() can be used to decide which
4387 ** of the first six interface should be used to extract the column value.
4388 ** The value returned by sqlite3_column_type() is only meaningful if no
4389 ** automatic type conversions have occurred for the value in question.
4390 ** After a type conversion, the result of calling sqlite3_column_type()
4391 ** is undefined, though harmless. Future
4392 ** versions of SQLite may change the behavior of sqlite3_column_type()
4393 ** following a type conversion.
4395 ** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
4396 ** or sqlite3_column_bytes16() interfaces can be used to determine the size
4397 ** of that BLOB or string.
4399 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
4400 ** routine returns the number of bytes in that BLOB or string.
4401 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
4402 ** the string to UTF-8 and then returns the number of bytes.
4403 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
4404 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
4405 ** the number of bytes in that string.
4406 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
4408 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
4409 ** routine returns the number of bytes in that BLOB or string.
4410 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
4411 ** the string to UTF-16 and then returns the number of bytes.
4412 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
4413 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
4414 ** the number of bytes in that string.
4415 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
4417 ** ^The values returned by [sqlite3_column_bytes()] and
4418 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
4419 ** of the string. ^For clarity: the values returned by
4420 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
4421 ** bytes in the string, not the number of characters.
4423 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
4424 ** even empty strings, are always zero-terminated. ^The return
4425 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
4427 ** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
4428 ** [unprotected sqlite3_value] object. In a multithreaded environment,
4429 ** an unprotected sqlite3_value object may only be used safely with
4430 ** [sqlite3_bind_value()] and [sqlite3_result_value()].
4431 ** If the [unprotected sqlite3_value] object returned by
4432 ** [sqlite3_column_value()] is used in any other way, including calls
4433 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
4434 ** or [sqlite3_value_bytes()], the behavior is not threadsafe.
4435 ** Hence, the sqlite3_column_value() interface
4436 ** is normally only useful within the implementation of
4437 ** [application-defined SQL functions] or [virtual tables], not within
4438 ** top-level application code.
4440 ** The these routines may attempt to convert the datatype of the result.
4441 ** ^For example, if the internal representation is FLOAT and a text result
4442 ** is requested, [sqlite3_snprintf()] is used internally to perform the
4443 ** conversion automatically. ^(The following table details the conversions
4444 ** that are applied:
4446 ** <blockquote>
4447 ** <table border="1">
4448 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
4450 ** <tr><td> NULL <td> INTEGER <td> Result is 0
4451 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
4452 ** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer
4453 ** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer
4454 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
4455 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
4456 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
4457 ** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER
4458 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
4459 ** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB
4460 ** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER
4461 ** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL
4462 ** <tr><td> TEXT <td> BLOB <td> No change
4463 ** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER
4464 ** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL
4465 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
4466 ** </table>
4467 ** </blockquote>)^
4469 ** Note that when type conversions occur, pointers returned by prior
4470 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
4471 ** sqlite3_column_text16() may be invalidated.
4472 ** Type conversions and pointer invalidations might occur
4473 ** in the following cases:
4475 ** <ul>
4476 ** <li> The initial content is a BLOB and sqlite3_column_text() or
4477 ** sqlite3_column_text16() is called. A zero-terminator might
4478 ** need to be added to the string.</li>
4479 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
4480 ** sqlite3_column_text16() is called. The content must be converted
4481 ** to UTF-16.</li>
4482 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
4483 ** sqlite3_column_text() is called. The content must be converted
4484 ** to UTF-8.</li>
4485 ** </ul>
4487 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
4488 ** not invalidate a prior pointer, though of course the content of the buffer
4489 ** that the prior pointer references will have been modified. Other kinds
4490 ** of conversion are done in place when it is possible, but sometimes they
4491 ** are not possible and in those cases prior pointers are invalidated.
4493 ** The safest policy is to invoke these routines
4494 ** in one of the following ways:
4496 ** <ul>
4497 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
4498 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
4499 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
4500 ** </ul>
4502 ** In other words, you should call sqlite3_column_text(),
4503 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
4504 ** into the desired format, then invoke sqlite3_column_bytes() or
4505 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
4506 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
4507 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
4508 ** with calls to sqlite3_column_bytes().
4510 ** ^The pointers returned are valid until a type conversion occurs as
4511 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
4512 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
4513 ** and BLOBs is freed automatically. Do not pass the pointers returned
4514 ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
4515 ** [sqlite3_free()].
4517 ** ^(If a memory allocation error occurs during the evaluation of any
4518 ** of these routines, a default value is returned. The default value
4519 ** is either the integer 0, the floating point number 0.0, or a NULL
4520 ** pointer. Subsequent calls to [sqlite3_errcode()] will return
4521 ** [SQLITE_NOMEM].)^
4523 const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
4524 double sqlite3_column_double(sqlite3_stmt*, int iCol);
4525 int sqlite3_column_int(sqlite3_stmt*, int iCol);
4526 sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
4527 const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
4528 const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
4529 sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
4530 int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
4531 int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
4532 int sqlite3_column_type(sqlite3_stmt*, int iCol);
4535 ** CAPI3REF: Destroy A Prepared Statement Object
4536 ** DESTRUCTOR: sqlite3_stmt
4538 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4539 ** ^If the most recent evaluation of the statement encountered no errors
4540 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
4541 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
4542 ** sqlite3_finalize(S) returns the appropriate [error code] or
4543 ** [extended error code].
4545 ** ^The sqlite3_finalize(S) routine can be called at any point during
4546 ** the life cycle of [prepared statement] S:
4547 ** before statement S is ever evaluated, after
4548 ** one or more calls to [sqlite3_reset()], or after any call
4549 ** to [sqlite3_step()] regardless of whether or not the statement has
4550 ** completed execution.
4552 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4554 ** The application must finalize every [prepared statement] in order to avoid
4555 ** resource leaks. It is a grievous error for the application to try to use
4556 ** a prepared statement after it has been finalized. Any use of a prepared
4557 ** statement after it has been finalized can result in undefined and
4558 ** undesirable behavior such as segfaults and heap corruption.
4560 int sqlite3_finalize(sqlite3_stmt *pStmt);
4563 ** CAPI3REF: Reset A Prepared Statement Object
4564 ** METHOD: sqlite3_stmt
4566 ** The sqlite3_reset() function is called to reset a [prepared statement]
4567 ** object back to its initial state, ready to be re-executed.
4568 ** ^Any SQL statement variables that had values bound to them using
4569 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4570 ** Use [sqlite3_clear_bindings()] to reset the bindings.
4572 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4573 ** back to the beginning of its program.
4575 ** ^If the most recent call to [sqlite3_step(S)] for the
4576 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4577 ** or if [sqlite3_step(S)] has never before been called on S,
4578 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
4580 ** ^If the most recent call to [sqlite3_step(S)] for the
4581 ** [prepared statement] S indicated an error, then
4582 ** [sqlite3_reset(S)] returns an appropriate [error code].
4584 ** ^The [sqlite3_reset(S)] interface does not change the values
4585 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4587 int sqlite3_reset(sqlite3_stmt *pStmt);
4590 ** CAPI3REF: Create Or Redefine SQL Functions
4591 ** KEYWORDS: {function creation routines}
4592 ** KEYWORDS: {application-defined SQL function}
4593 ** KEYWORDS: {application-defined SQL functions}
4594 ** METHOD: sqlite3
4596 ** ^These functions (collectively known as "function creation routines")
4597 ** are used to add SQL functions or aggregates or to redefine the behavior
4598 ** of existing SQL functions or aggregates. The only differences between
4599 ** these routines are the text encoding expected for
4600 ** the second parameter (the name of the function being created)
4601 ** and the presence or absence of a destructor callback for
4602 ** the application data pointer.
4604 ** ^The first parameter is the [database connection] to which the SQL
4605 ** function is to be added. ^If an application uses more than one database
4606 ** connection then application-defined SQL functions must be added
4607 ** to each database connection separately.
4609 ** ^The second parameter is the name of the SQL function to be created or
4610 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
4611 ** representation, exclusive of the zero-terminator. ^Note that the name
4612 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4613 ** ^Any attempt to create a function with a longer name
4614 ** will result in [SQLITE_MISUSE] being returned.
4616 ** ^The third parameter (nArg)
4617 ** is the number of arguments that the SQL function or
4618 ** aggregate takes. ^If this parameter is -1, then the SQL function or
4619 ** aggregate may take any number of arguments between 0 and the limit
4620 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
4621 ** parameter is less than -1 or greater than 127 then the behavior is
4622 ** undefined.
4624 ** ^The fourth parameter, eTextRep, specifies what
4625 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4626 ** its parameters. The application should set this parameter to
4627 ** [SQLITE_UTF16LE] if the function implementation invokes
4628 ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4629 ** implementation invokes [sqlite3_value_text16be()] on an input, or
4630 ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4631 ** otherwise. ^The same SQL function may be registered multiple times using
4632 ** different preferred text encodings, with different implementations for
4633 ** each encoding.
4634 ** ^When multiple implementations of the same function are available, SQLite
4635 ** will pick the one that involves the least amount of data conversion.
4637 ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4638 ** to signal that the function will always return the same result given
4639 ** the same inputs within a single SQL statement. Most SQL functions are
4640 ** deterministic. The built-in [random()] SQL function is an example of a
4641 ** function that is not deterministic. The SQLite query planner is able to
4642 ** perform additional optimizations on deterministic functions, so use
4643 ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4645 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
4646 ** function can gain access to this pointer using [sqlite3_user_data()].)^
4648 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
4649 ** pointers to C-language functions that implement the SQL function or
4650 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4651 ** callback only; NULL pointers must be passed as the xStep and xFinal
4652 ** parameters. ^An aggregate SQL function requires an implementation of xStep
4653 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4654 ** SQL function or aggregate, pass NULL pointers for all three function
4655 ** callbacks.
4657 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
4658 ** then it is destructor for the application data pointer.
4659 ** The destructor is invoked when the function is deleted, either by being
4660 ** overloaded or when the database connection closes.)^
4661 ** ^The destructor is also invoked if the call to
4662 ** sqlite3_create_function_v2() fails.
4663 ** ^When the destructor callback of the tenth parameter is invoked, it
4664 ** is passed a single argument which is a copy of the application data
4665 ** pointer which was the fifth parameter to sqlite3_create_function_v2().
4667 ** ^It is permitted to register multiple implementations of the same
4668 ** functions with the same name but with either differing numbers of
4669 ** arguments or differing preferred text encodings. ^SQLite will use
4670 ** the implementation that most closely matches the way in which the
4671 ** SQL function is used. ^A function implementation with a non-negative
4672 ** nArg parameter is a better match than a function implementation with
4673 ** a negative nArg. ^A function where the preferred text encoding
4674 ** matches the database encoding is a better
4675 ** match than a function where the encoding is different.
4676 ** ^A function where the encoding difference is between UTF16le and UTF16be
4677 ** is a closer match than a function where the encoding difference is
4678 ** between UTF8 and UTF16.
4680 ** ^Built-in functions may be overloaded by new application-defined functions.
4682 ** ^An application-defined function is permitted to call other
4683 ** SQLite interfaces. However, such calls must not
4684 ** close the database connection nor finalize or reset the prepared
4685 ** statement in which the function is running.
4687 int sqlite3_create_function(
4688 sqlite3 *db,
4689 const char *zFunctionName,
4690 int nArg,
4691 int eTextRep,
4692 void *pApp,
4693 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4694 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4695 void (*xFinal)(sqlite3_context*)
4697 int sqlite3_create_function16(
4698 sqlite3 *db,
4699 const void *zFunctionName,
4700 int nArg,
4701 int eTextRep,
4702 void *pApp,
4703 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4704 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4705 void (*xFinal)(sqlite3_context*)
4707 int sqlite3_create_function_v2(
4708 sqlite3 *db,
4709 const char *zFunctionName,
4710 int nArg,
4711 int eTextRep,
4712 void *pApp,
4713 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4714 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4715 void (*xFinal)(sqlite3_context*),
4716 void(*xDestroy)(void*)
4720 ** CAPI3REF: Text Encodings
4722 ** These constant define integer codes that represent the various
4723 ** text encodings supported by SQLite.
4725 #define SQLITE_UTF8 1 /* IMP: R-37514-35566 */
4726 #define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */
4727 #define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */
4728 #define SQLITE_UTF16 4 /* Use native byte order */
4729 #define SQLITE_ANY 5 /* Deprecated */
4730 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
4733 ** CAPI3REF: Function Flags
4735 ** These constants may be ORed together with the
4736 ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4737 ** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4738 ** [sqlite3_create_function_v2()].
4740 #define SQLITE_DETERMINISTIC 0x800
4743 ** CAPI3REF: Deprecated Functions
4744 ** DEPRECATED
4746 ** These functions are [deprecated]. In order to maintain
4747 ** backwards compatibility with older code, these functions continue
4748 ** to be supported. However, new applications should avoid
4749 ** the use of these functions. To encourage programmers to avoid
4750 ** these functions, we will not explain what they do.
4752 #ifndef SQLITE_OMIT_DEPRECATED
4753 SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
4754 SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
4755 SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4756 SQLITE_DEPRECATED int sqlite3_global_recover(void);
4757 SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
4758 SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4759 void*,sqlite3_int64);
4760 #endif
4763 ** CAPI3REF: Obtaining SQL Values
4764 ** METHOD: sqlite3_value
4766 ** <b>Summary:</b>
4767 ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
4768 ** <tr><td><b>sqlite3_value_blob</b><td>&rarr;<td>BLOB value
4769 ** <tr><td><b>sqlite3_value_double</b><td>&rarr;<td>REAL value
4770 ** <tr><td><b>sqlite3_value_int</b><td>&rarr;<td>32-bit INTEGER value
4771 ** <tr><td><b>sqlite3_value_int64</b><td>&rarr;<td>64-bit INTEGER value
4772 ** <tr><td><b>sqlite3_value_pointer</b><td>&rarr;<td>Pointer value
4773 ** <tr><td><b>sqlite3_value_text</b><td>&rarr;<td>UTF-8 TEXT value
4774 ** <tr><td><b>sqlite3_value_text16</b><td>&rarr;<td>UTF-16 TEXT value in
4775 ** the native byteorder
4776 ** <tr><td><b>sqlite3_value_text16be</b><td>&rarr;<td>UTF-16be TEXT value
4777 ** <tr><td><b>sqlite3_value_text16le</b><td>&rarr;<td>UTF-16le TEXT value
4778 ** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
4779 ** <tr><td><b>sqlite3_value_bytes</b><td>&rarr;<td>Size of a BLOB
4780 ** or a UTF-8 TEXT in bytes
4781 ** <tr><td><b>sqlite3_value_bytes16&nbsp;&nbsp;</b>
4782 ** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
4783 ** TEXT in bytes
4784 ** <tr><td><b>sqlite3_value_type</b><td>&rarr;<td>Default
4785 ** datatype of the value
4786 ** <tr><td><b>sqlite3_value_numeric_type&nbsp;&nbsp;</b>
4787 ** <td>&rarr;&nbsp;&nbsp;<td>Best numeric datatype of the value
4788 ** <tr><td><b>sqlite3_value_nochange&nbsp;&nbsp;</b>
4789 ** <td>&rarr;&nbsp;&nbsp;<td>True if the column is unchanged in an UPDATE
4790 ** against a virtual table.
4791 ** </table></blockquote>
4793 ** <b>Details:</b>
4795 ** These routines extract type, size, and content information from
4796 ** [protected sqlite3_value] objects. Protected sqlite3_value objects
4797 ** are used to pass parameter information into implementation of
4798 ** [application-defined SQL functions] and [virtual tables].
4800 ** These routines work only with [protected sqlite3_value] objects.
4801 ** Any attempt to use these routines on an [unprotected sqlite3_value]
4802 ** is not threadsafe.
4804 ** ^These routines work just like the corresponding [column access functions]
4805 ** except that these routines take a single [protected sqlite3_value] object
4806 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4808 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4809 ** in the native byte-order of the host machine. ^The
4810 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4811 ** extract UTF-16 strings as big-endian and little-endian respectively.
4813 ** ^If [sqlite3_value] object V was initialized
4814 ** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
4815 ** and if X and Y are strings that compare equal according to strcmp(X,Y),
4816 ** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise,
4817 ** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
4818 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
4820 ** ^(The sqlite3_value_type(V) interface returns the
4821 ** [SQLITE_INTEGER | datatype code] for the initial datatype of the
4822 ** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
4823 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
4824 ** Other interfaces might change the datatype for an sqlite3_value object.
4825 ** For example, if the datatype is initially SQLITE_INTEGER and
4826 ** sqlite3_value_text(V) is called to extract a text value for that
4827 ** integer, then subsequent calls to sqlite3_value_type(V) might return
4828 ** SQLITE_TEXT. Whether or not a persistent internal datatype conversion
4829 ** occurs is undefined and may change from one release of SQLite to the next.
4831 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
4832 ** numeric affinity to the value. This means that an attempt is
4833 ** made to convert the value to an integer or floating point. If
4834 ** such a conversion is possible without loss of information (in other
4835 ** words, if the value is a string that looks like a number)
4836 ** then the conversion is performed. Otherwise no conversion occurs.
4837 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4839 ** ^Within the [xUpdate] method of a [virtual table], the
4840 ** sqlite3_value_nochange(X) interface returns true if and only if
4841 ** the column corresponding to X is unchanged by the UPDATE operation
4842 ** that the xUpdate method call was invoked to implement and if
4843 ** and the prior [xColumn] method call that was invoked to extracted
4844 ** the value for that column returned without setting a result (probably
4845 ** because it queried [sqlite3_vtab_nochange()] and found that the column
4846 ** was unchanging). ^Within an [xUpdate] method, any value for which
4847 ** sqlite3_value_nochange(X) is true will in all other respects appear
4848 ** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other
4849 ** than within an [xUpdate] method call for an UPDATE statement, then
4850 ** the return value is arbitrary and meaningless.
4852 ** Please pay particular attention to the fact that the pointer returned
4853 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4854 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4855 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4856 ** or [sqlite3_value_text16()].
4858 ** These routines must be called from the same thread as
4859 ** the SQL function that supplied the [sqlite3_value*] parameters.
4861 const void *sqlite3_value_blob(sqlite3_value*);
4862 double sqlite3_value_double(sqlite3_value*);
4863 int sqlite3_value_int(sqlite3_value*);
4864 sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
4865 void *sqlite3_value_pointer(sqlite3_value*, const char*);
4866 const unsigned char *sqlite3_value_text(sqlite3_value*);
4867 const void *sqlite3_value_text16(sqlite3_value*);
4868 const void *sqlite3_value_text16le(sqlite3_value*);
4869 const void *sqlite3_value_text16be(sqlite3_value*);
4870 int sqlite3_value_bytes(sqlite3_value*);
4871 int sqlite3_value_bytes16(sqlite3_value*);
4872 int sqlite3_value_type(sqlite3_value*);
4873 int sqlite3_value_numeric_type(sqlite3_value*);
4874 int sqlite3_value_nochange(sqlite3_value*);
4877 ** CAPI3REF: Finding The Subtype Of SQL Values
4878 ** METHOD: sqlite3_value
4880 ** The sqlite3_value_subtype(V) function returns the subtype for
4881 ** an [application-defined SQL function] argument V. The subtype
4882 ** information can be used to pass a limited amount of context from
4883 ** one SQL function to another. Use the [sqlite3_result_subtype()]
4884 ** routine to set the subtype for the return value of an SQL function.
4886 unsigned int sqlite3_value_subtype(sqlite3_value*);
4889 ** CAPI3REF: Copy And Free SQL Values
4890 ** METHOD: sqlite3_value
4892 ** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
4893 ** object D and returns a pointer to that copy. ^The [sqlite3_value] returned
4894 ** is a [protected sqlite3_value] object even if the input is not.
4895 ** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
4896 ** memory allocation fails.
4898 ** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
4899 ** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer
4900 ** then sqlite3_value_free(V) is a harmless no-op.
4902 sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
4903 void sqlite3_value_free(sqlite3_value*);
4906 ** CAPI3REF: Obtain Aggregate Function Context
4907 ** METHOD: sqlite3_context
4909 ** Implementations of aggregate SQL functions use this
4910 ** routine to allocate memory for storing their state.
4912 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4913 ** for a particular aggregate function, SQLite
4914 ** allocates N of memory, zeroes out that memory, and returns a pointer
4915 ** to the new memory. ^On second and subsequent calls to
4916 ** sqlite3_aggregate_context() for the same aggregate function instance,
4917 ** the same buffer is returned. Sqlite3_aggregate_context() is normally
4918 ** called once for each invocation of the xStep callback and then one
4919 ** last time when the xFinal callback is invoked. ^(When no rows match
4920 ** an aggregate query, the xStep() callback of the aggregate function
4921 ** implementation is never called and xFinal() is called exactly once.
4922 ** In those cases, sqlite3_aggregate_context() might be called for the
4923 ** first time from within xFinal().)^
4925 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
4926 ** when first called if N is less than or equal to zero or if a memory
4927 ** allocate error occurs.
4929 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4930 ** determined by the N parameter on first successful call. Changing the
4931 ** value of N in subsequent call to sqlite3_aggregate_context() within
4932 ** the same aggregate function instance will not resize the memory
4933 ** allocation.)^ Within the xFinal callback, it is customary to set
4934 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
4935 ** pointless memory allocations occur.
4937 ** ^SQLite automatically frees the memory allocated by
4938 ** sqlite3_aggregate_context() when the aggregate query concludes.
4940 ** The first parameter must be a copy of the
4941 ** [sqlite3_context | SQL function context] that is the first parameter
4942 ** to the xStep or xFinal callback routine that implements the aggregate
4943 ** function.
4945 ** This routine must be called from the same thread in which
4946 ** the aggregate SQL function is running.
4948 void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4951 ** CAPI3REF: User Data For Functions
4952 ** METHOD: sqlite3_context
4954 ** ^The sqlite3_user_data() interface returns a copy of
4955 ** the pointer that was the pUserData parameter (the 5th parameter)
4956 ** of the [sqlite3_create_function()]
4957 ** and [sqlite3_create_function16()] routines that originally
4958 ** registered the application defined function.
4960 ** This routine must be called from the same thread in which
4961 ** the application-defined function is running.
4963 void *sqlite3_user_data(sqlite3_context*);
4966 ** CAPI3REF: Database Connection For Functions
4967 ** METHOD: sqlite3_context
4969 ** ^The sqlite3_context_db_handle() interface returns a copy of
4970 ** the pointer to the [database connection] (the 1st parameter)
4971 ** of the [sqlite3_create_function()]
4972 ** and [sqlite3_create_function16()] routines that originally
4973 ** registered the application defined function.
4975 sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
4978 ** CAPI3REF: Function Auxiliary Data
4979 ** METHOD: sqlite3_context
4981 ** These functions may be used by (non-aggregate) SQL functions to
4982 ** associate metadata with argument values. If the same value is passed to
4983 ** multiple invocations of the same SQL function during query execution, under
4984 ** some circumstances the associated metadata may be preserved. An example
4985 ** of where this might be useful is in a regular-expression matching
4986 ** function. The compiled version of the regular expression can be stored as
4987 ** metadata associated with the pattern string.
4988 ** Then as long as the pattern string remains the same,
4989 ** the compiled regular expression can be reused on multiple
4990 ** invocations of the same function.
4992 ** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata
4993 ** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
4994 ** value to the application-defined function. ^N is zero for the left-most
4995 ** function argument. ^If there is no metadata
4996 ** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
4997 ** returns a NULL pointer.
4999 ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
5000 ** argument of the application-defined function. ^Subsequent
5001 ** calls to sqlite3_get_auxdata(C,N) return P from the most recent
5002 ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
5003 ** NULL if the metadata has been discarded.
5004 ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
5005 ** SQLite will invoke the destructor function X with parameter P exactly
5006 ** once, when the metadata is discarded.
5007 ** SQLite is free to discard the metadata at any time, including: <ul>
5008 ** <li> ^(when the corresponding function parameter changes)^, or
5009 ** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
5010 ** SQL statement)^, or
5011 ** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
5012 ** parameter)^, or
5013 ** <li> ^(during the original sqlite3_set_auxdata() call when a memory
5014 ** allocation error occurs.)^ </ul>
5016 ** Note the last bullet in particular. The destructor X in
5017 ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
5018 ** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
5019 ** should be called near the end of the function implementation and the
5020 ** function implementation should not make any use of P after
5021 ** sqlite3_set_auxdata() has been called.
5023 ** ^(In practice, metadata is preserved between function calls for
5024 ** function parameters that are compile-time constants, including literal
5025 ** values and [parameters] and expressions composed from the same.)^
5027 ** The value of the N parameter to these interfaces should be non-negative.
5028 ** Future enhancements may make use of negative N values to define new
5029 ** kinds of function caching behavior.
5031 ** These routines must be called from the same thread in which
5032 ** the SQL function is running.
5034 void *sqlite3_get_auxdata(sqlite3_context*, int N);
5035 void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
5039 ** CAPI3REF: Constants Defining Special Destructor Behavior
5041 ** These are special values for the destructor that is passed in as the
5042 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
5043 ** argument is SQLITE_STATIC, it means that the content pointer is constant
5044 ** and will never change. It does not need to be destroyed. ^The
5045 ** SQLITE_TRANSIENT value means that the content will likely change in
5046 ** the near future and that SQLite should make its own private copy of
5047 ** the content before returning.
5049 ** The typedef is necessary to work around problems in certain
5050 ** C++ compilers.
5052 typedef void (*sqlite3_destructor_type)(void*);
5053 #define SQLITE_STATIC ((sqlite3_destructor_type)0)
5054 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
5057 ** CAPI3REF: Setting The Result Of An SQL Function
5058 ** METHOD: sqlite3_context
5060 ** These routines are used by the xFunc or xFinal callbacks that
5061 ** implement SQL functions and aggregates. See
5062 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
5063 ** for additional information.
5065 ** These functions work very much like the [parameter binding] family of
5066 ** functions used to bind values to host parameters in prepared statements.
5067 ** Refer to the [SQL parameter] documentation for additional information.
5069 ** ^The sqlite3_result_blob() interface sets the result from
5070 ** an application-defined function to be the BLOB whose content is pointed
5071 ** to by the second parameter and which is N bytes long where N is the
5072 ** third parameter.
5074 ** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
5075 ** interfaces set the result of the application-defined function to be
5076 ** a BLOB containing all zero bytes and N bytes in size.
5078 ** ^The sqlite3_result_double() interface sets the result from
5079 ** an application-defined function to be a floating point value specified
5080 ** by its 2nd argument.
5082 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
5083 ** cause the implemented SQL function to throw an exception.
5084 ** ^SQLite uses the string pointed to by the
5085 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
5086 ** as the text of an error message. ^SQLite interprets the error
5087 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
5088 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
5089 ** byte order. ^If the third parameter to sqlite3_result_error()
5090 ** or sqlite3_result_error16() is negative then SQLite takes as the error
5091 ** message all text up through the first zero character.
5092 ** ^If the third parameter to sqlite3_result_error() or
5093 ** sqlite3_result_error16() is non-negative then SQLite takes that many
5094 ** bytes (not characters) from the 2nd parameter as the error message.
5095 ** ^The sqlite3_result_error() and sqlite3_result_error16()
5096 ** routines make a private copy of the error message text before
5097 ** they return. Hence, the calling function can deallocate or
5098 ** modify the text after they return without harm.
5099 ** ^The sqlite3_result_error_code() function changes the error code
5100 ** returned by SQLite as a result of an error in a function. ^By default,
5101 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
5102 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
5104 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
5105 ** error indicating that a string or BLOB is too long to represent.
5107 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
5108 ** error indicating that a memory allocation failed.
5110 ** ^The sqlite3_result_int() interface sets the return value
5111 ** of the application-defined function to be the 32-bit signed integer
5112 ** value given in the 2nd argument.
5113 ** ^The sqlite3_result_int64() interface sets the return value
5114 ** of the application-defined function to be the 64-bit signed integer
5115 ** value given in the 2nd argument.
5117 ** ^The sqlite3_result_null() interface sets the return value
5118 ** of the application-defined function to be NULL.
5120 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
5121 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
5122 ** set the return value of the application-defined function to be
5123 ** a text string which is represented as UTF-8, UTF-16 native byte order,
5124 ** UTF-16 little endian, or UTF-16 big endian, respectively.
5125 ** ^The sqlite3_result_text64() interface sets the return value of an
5126 ** application-defined function to be a text string in an encoding
5127 ** specified by the fifth (and last) parameter, which must be one
5128 ** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
5129 ** ^SQLite takes the text result from the application from
5130 ** the 2nd parameter of the sqlite3_result_text* interfaces.
5131 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5132 ** is negative, then SQLite takes result text from the 2nd parameter
5133 ** through the first zero character.
5134 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5135 ** is non-negative, then as many bytes (not characters) of the text
5136 ** pointed to by the 2nd parameter are taken as the application-defined
5137 ** function result. If the 3rd parameter is non-negative, then it
5138 ** must be the byte offset into the string where the NUL terminator would
5139 ** appear if the string where NUL terminated. If any NUL characters occur
5140 ** in the string at a byte offset that is less than the value of the 3rd
5141 ** parameter, then the resulting string will contain embedded NULs and the
5142 ** result of expressions operating on strings with embedded NULs is undefined.
5143 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
5144 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
5145 ** function as the destructor on the text or BLOB result when it has
5146 ** finished using that result.
5147 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
5148 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
5149 ** assumes that the text or BLOB result is in constant space and does not
5150 ** copy the content of the parameter nor call a destructor on the content
5151 ** when it has finished using that result.
5152 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
5153 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
5154 ** then SQLite makes a copy of the result into space obtained
5155 ** from [sqlite3_malloc()] before it returns.
5157 ** ^The sqlite3_result_value() interface sets the result of
5158 ** the application-defined function to be a copy of the
5159 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
5160 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
5161 ** so that the [sqlite3_value] specified in the parameter may change or
5162 ** be deallocated after sqlite3_result_value() returns without harm.
5163 ** ^A [protected sqlite3_value] object may always be used where an
5164 ** [unprotected sqlite3_value] object is required, so either
5165 ** kind of [sqlite3_value] object can be used with this interface.
5167 ** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
5168 ** SQL NULL value, just like [sqlite3_result_null(C)], except that it
5169 ** also associates the host-language pointer P or type T with that
5170 ** NULL value such that the pointer can be retrieved within an
5171 ** [application-defined SQL function] using [sqlite3_value_pointer()].
5172 ** ^If the D parameter is not NULL, then it is a pointer to a destructor
5173 ** for the P parameter. ^SQLite invokes D with P as its only argument
5174 ** when SQLite is finished with P. The T parameter should be a static
5175 ** string and preferably a string literal. The sqlite3_result_pointer()
5176 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5178 ** If these routines are called from within the different thread
5179 ** than the one containing the application-defined function that received
5180 ** the [sqlite3_context] pointer, the results are undefined.
5182 void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
5183 void sqlite3_result_blob64(sqlite3_context*,const void*,
5184 sqlite3_uint64,void(*)(void*));
5185 void sqlite3_result_double(sqlite3_context*, double);
5186 void sqlite3_result_error(sqlite3_context*, const char*, int);
5187 void sqlite3_result_error16(sqlite3_context*, const void*, int);
5188 void sqlite3_result_error_toobig(sqlite3_context*);
5189 void sqlite3_result_error_nomem(sqlite3_context*);
5190 void sqlite3_result_error_code(sqlite3_context*, int);
5191 void sqlite3_result_int(sqlite3_context*, int);
5192 void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
5193 void sqlite3_result_null(sqlite3_context*);
5194 void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
5195 void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
5196 void(*)(void*), unsigned char encoding);
5197 void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
5198 void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
5199 void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
5200 void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
5201 void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
5202 void sqlite3_result_zeroblob(sqlite3_context*, int n);
5203 int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
5207 ** CAPI3REF: Setting The Subtype Of An SQL Function
5208 ** METHOD: sqlite3_context
5210 ** The sqlite3_result_subtype(C,T) function causes the subtype of
5211 ** the result from the [application-defined SQL function] with
5212 ** [sqlite3_context] C to be the value T. Only the lower 8 bits
5213 ** of the subtype T are preserved in current versions of SQLite;
5214 ** higher order bits are discarded.
5215 ** The number of subtype bytes preserved by SQLite might increase
5216 ** in future releases of SQLite.
5218 void sqlite3_result_subtype(sqlite3_context*,unsigned int);
5221 ** CAPI3REF: Define New Collating Sequences
5222 ** METHOD: sqlite3
5224 ** ^These functions add, remove, or modify a [collation] associated
5225 ** with the [database connection] specified as the first argument.
5227 ** ^The name of the collation is a UTF-8 string
5228 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
5229 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
5230 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
5231 ** considered to be the same name.
5233 ** ^(The third argument (eTextRep) must be one of the constants:
5234 ** <ul>
5235 ** <li> [SQLITE_UTF8],
5236 ** <li> [SQLITE_UTF16LE],
5237 ** <li> [SQLITE_UTF16BE],
5238 ** <li> [SQLITE_UTF16], or
5239 ** <li> [SQLITE_UTF16_ALIGNED].
5240 ** </ul>)^
5241 ** ^The eTextRep argument determines the encoding of strings passed
5242 ** to the collating function callback, xCallback.
5243 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
5244 ** force strings to be UTF16 with native byte order.
5245 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
5246 ** on an even byte address.
5248 ** ^The fourth argument, pArg, is an application data pointer that is passed
5249 ** through as the first argument to the collating function callback.
5251 ** ^The fifth argument, xCallback, is a pointer to the collating function.
5252 ** ^Multiple collating functions can be registered using the same name but
5253 ** with different eTextRep parameters and SQLite will use whichever
5254 ** function requires the least amount of data transformation.
5255 ** ^If the xCallback argument is NULL then the collating function is
5256 ** deleted. ^When all collating functions having the same name are deleted,
5257 ** that collation is no longer usable.
5259 ** ^The collating function callback is invoked with a copy of the pArg
5260 ** application data pointer and with two strings in the encoding specified
5261 ** by the eTextRep argument. The collating function must return an
5262 ** integer that is negative, zero, or positive
5263 ** if the first string is less than, equal to, or greater than the second,
5264 ** respectively. A collating function must always return the same answer
5265 ** given the same inputs. If two or more collating functions are registered
5266 ** to the same collation name (using different eTextRep values) then all
5267 ** must give an equivalent answer when invoked with equivalent strings.
5268 ** The collating function must obey the following properties for all
5269 ** strings A, B, and C:
5271 ** <ol>
5272 ** <li> If A==B then B==A.
5273 ** <li> If A==B and B==C then A==C.
5274 ** <li> If A&lt;B THEN B&gt;A.
5275 ** <li> If A&lt;B and B&lt;C then A&lt;C.
5276 ** </ol>
5278 ** If a collating function fails any of the above constraints and that
5279 ** collating function is registered and used, then the behavior of SQLite
5280 ** is undefined.
5282 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
5283 ** with the addition that the xDestroy callback is invoked on pArg when
5284 ** the collating function is deleted.
5285 ** ^Collating functions are deleted when they are overridden by later
5286 ** calls to the collation creation functions or when the
5287 ** [database connection] is closed using [sqlite3_close()].
5289 ** ^The xDestroy callback is <u>not</u> called if the
5290 ** sqlite3_create_collation_v2() function fails. Applications that invoke
5291 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
5292 ** check the return code and dispose of the application data pointer
5293 ** themselves rather than expecting SQLite to deal with it for them.
5294 ** This is different from every other SQLite interface. The inconsistency
5295 ** is unfortunate but cannot be changed without breaking backwards
5296 ** compatibility.
5298 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
5300 int sqlite3_create_collation(
5301 sqlite3*,
5302 const char *zName,
5303 int eTextRep,
5304 void *pArg,
5305 int(*xCompare)(void*,int,const void*,int,const void*)
5307 int sqlite3_create_collation_v2(
5308 sqlite3*,
5309 const char *zName,
5310 int eTextRep,
5311 void *pArg,
5312 int(*xCompare)(void*,int,const void*,int,const void*),
5313 void(*xDestroy)(void*)
5315 int sqlite3_create_collation16(
5316 sqlite3*,
5317 const void *zName,
5318 int eTextRep,
5319 void *pArg,
5320 int(*xCompare)(void*,int,const void*,int,const void*)
5324 ** CAPI3REF: Collation Needed Callbacks
5325 ** METHOD: sqlite3
5327 ** ^To avoid having to register all collation sequences before a database
5328 ** can be used, a single callback function may be registered with the
5329 ** [database connection] to be invoked whenever an undefined collation
5330 ** sequence is required.
5332 ** ^If the function is registered using the sqlite3_collation_needed() API,
5333 ** then it is passed the names of undefined collation sequences as strings
5334 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
5335 ** the names are passed as UTF-16 in machine native byte order.
5336 ** ^A call to either function replaces the existing collation-needed callback.
5338 ** ^(When the callback is invoked, the first argument passed is a copy
5339 ** of the second argument to sqlite3_collation_needed() or
5340 ** sqlite3_collation_needed16(). The second argument is the database
5341 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
5342 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
5343 ** sequence function required. The fourth parameter is the name of the
5344 ** required collation sequence.)^
5346 ** The callback function should register the desired collation using
5347 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
5348 ** [sqlite3_create_collation_v2()].
5350 int sqlite3_collation_needed(
5351 sqlite3*,
5352 void*,
5353 void(*)(void*,sqlite3*,int eTextRep,const char*)
5355 int sqlite3_collation_needed16(
5356 sqlite3*,
5357 void*,
5358 void(*)(void*,sqlite3*,int eTextRep,const void*)
5361 #ifdef SQLITE_HAS_CODEC
5363 ** Specify the key for an encrypted database. This routine should be
5364 ** called right after sqlite3_open().
5366 ** The code to implement this API is not available in the public release
5367 ** of SQLite.
5369 int sqlite3_key(
5370 sqlite3 *db, /* Database to be rekeyed */
5371 const void *pKey, int nKey /* The key */
5373 int sqlite3_key_v2(
5374 sqlite3 *db, /* Database to be rekeyed */
5375 const char *zDbName, /* Name of the database */
5376 const void *pKey, int nKey /* The key */
5380 ** Change the key on an open database. If the current database is not
5381 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
5382 ** database is decrypted.
5384 ** The code to implement this API is not available in the public release
5385 ** of SQLite.
5387 int sqlite3_rekey(
5388 sqlite3 *db, /* Database to be rekeyed */
5389 const void *pKey, int nKey /* The new key */
5391 int sqlite3_rekey_v2(
5392 sqlite3 *db, /* Database to be rekeyed */
5393 const char *zDbName, /* Name of the database */
5394 const void *pKey, int nKey /* The new key */
5398 ** Specify the activation key for a SEE database. Unless
5399 ** activated, none of the SEE routines will work.
5401 void sqlite3_activate_see(
5402 const char *zPassPhrase /* Activation phrase */
5404 #endif
5406 #ifdef SQLITE_ENABLE_CEROD
5408 ** Specify the activation key for a CEROD database. Unless
5409 ** activated, none of the CEROD routines will work.
5411 void sqlite3_activate_cerod(
5412 const char *zPassPhrase /* Activation phrase */
5414 #endif
5417 ** CAPI3REF: Suspend Execution For A Short Time
5419 ** The sqlite3_sleep() function causes the current thread to suspend execution
5420 ** for at least a number of milliseconds specified in its parameter.
5422 ** If the operating system does not support sleep requests with
5423 ** millisecond time resolution, then the time will be rounded up to
5424 ** the nearest second. The number of milliseconds of sleep actually
5425 ** requested from the operating system is returned.
5427 ** ^SQLite implements this interface by calling the xSleep()
5428 ** method of the default [sqlite3_vfs] object. If the xSleep() method
5429 ** of the default VFS is not implemented correctly, or not implemented at
5430 ** all, then the behavior of sqlite3_sleep() may deviate from the description
5431 ** in the previous paragraphs.
5433 int sqlite3_sleep(int);
5436 ** CAPI3REF: Name Of The Folder Holding Temporary Files
5438 ** ^(If this global variable is made to point to a string which is
5439 ** the name of a folder (a.k.a. directory), then all temporary files
5440 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
5441 ** will be placed in that directory.)^ ^If this variable
5442 ** is a NULL pointer, then SQLite performs a search for an appropriate
5443 ** temporary file directory.
5445 ** Applications are strongly discouraged from using this global variable.
5446 ** It is required to set a temporary folder on Windows Runtime (WinRT).
5447 ** But for all other platforms, it is highly recommended that applications
5448 ** neither read nor write this variable. This global variable is a relic
5449 ** that exists for backwards compatibility of legacy applications and should
5450 ** be avoided in new projects.
5452 ** It is not safe to read or modify this variable in more than one
5453 ** thread at a time. It is not safe to read or modify this variable
5454 ** if a [database connection] is being used at the same time in a separate
5455 ** thread.
5456 ** It is intended that this variable be set once
5457 ** as part of process initialization and before any SQLite interface
5458 ** routines have been called and that this variable remain unchanged
5459 ** thereafter.
5461 ** ^The [temp_store_directory pragma] may modify this variable and cause
5462 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
5463 ** the [temp_store_directory pragma] always assumes that any string
5464 ** that this variable points to is held in memory obtained from
5465 ** [sqlite3_malloc] and the pragma may attempt to free that memory
5466 ** using [sqlite3_free].
5467 ** Hence, if this variable is modified directly, either it should be
5468 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
5469 ** or else the use of the [temp_store_directory pragma] should be avoided.
5470 ** Except when requested by the [temp_store_directory pragma], SQLite
5471 ** does not free the memory that sqlite3_temp_directory points to. If
5472 ** the application wants that memory to be freed, it must do
5473 ** so itself, taking care to only do so after all [database connection]
5474 ** objects have been destroyed.
5476 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
5477 ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
5478 ** features that require the use of temporary files may fail. Here is an
5479 ** example of how to do this using C++ with the Windows Runtime:
5481 ** <blockquote><pre>
5482 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
5483 ** &nbsp; TemporaryFolder->Path->Data();
5484 ** char zPathBuf&#91;MAX_PATH + 1&#93;;
5485 ** memset(zPathBuf, 0, sizeof(zPathBuf));
5486 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
5487 ** &nbsp; NULL, NULL);
5488 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
5489 ** </pre></blockquote>
5491 SQLITE_EXTERN char *sqlite3_temp_directory;
5494 ** CAPI3REF: Name Of The Folder Holding Database Files
5496 ** ^(If this global variable is made to point to a string which is
5497 ** the name of a folder (a.k.a. directory), then all database files
5498 ** specified with a relative pathname and created or accessed by
5499 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
5500 ** to be relative to that directory.)^ ^If this variable is a NULL
5501 ** pointer, then SQLite assumes that all database files specified
5502 ** with a relative pathname are relative to the current directory
5503 ** for the process. Only the windows VFS makes use of this global
5504 ** variable; it is ignored by the unix VFS.
5506 ** Changing the value of this variable while a database connection is
5507 ** open can result in a corrupt database.
5509 ** It is not safe to read or modify this variable in more than one
5510 ** thread at a time. It is not safe to read or modify this variable
5511 ** if a [database connection] is being used at the same time in a separate
5512 ** thread.
5513 ** It is intended that this variable be set once
5514 ** as part of process initialization and before any SQLite interface
5515 ** routines have been called and that this variable remain unchanged
5516 ** thereafter.
5518 ** ^The [data_store_directory pragma] may modify this variable and cause
5519 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
5520 ** the [data_store_directory pragma] always assumes that any string
5521 ** that this variable points to is held in memory obtained from
5522 ** [sqlite3_malloc] and the pragma may attempt to free that memory
5523 ** using [sqlite3_free].
5524 ** Hence, if this variable is modified directly, either it should be
5525 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
5526 ** or else the use of the [data_store_directory pragma] should be avoided.
5528 SQLITE_EXTERN char *sqlite3_data_directory;
5531 ** CAPI3REF: Win32 Specific Interface
5533 ** These interfaces are available only on Windows. The
5534 ** [sqlite3_win32_set_directory] interface is used to set the value associated
5535 ** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
5536 ** zValue, depending on the value of the type parameter. The zValue parameter
5537 ** should be NULL to cause the previous value to be freed via [sqlite3_free];
5538 ** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
5539 ** prior to being used. The [sqlite3_win32_set_directory] interface returns
5540 ** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
5541 ** or [SQLITE_NOMEM] if memory could not be allocated. The value of the
5542 ** [sqlite3_data_directory] variable is intended to act as a replacement for
5543 ** the current directory on the sub-platforms of Win32 where that concept is
5544 ** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and
5545 ** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
5546 ** sqlite3_win32_set_directory interface except the string parameter must be
5547 ** UTF-8 or UTF-16, respectively.
5549 int sqlite3_win32_set_directory(
5550 unsigned long type, /* Identifier for directory being set or reset */
5551 void *zValue /* New value for directory being set or reset */
5553 int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
5554 int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
5557 ** CAPI3REF: Win32 Directory Types
5559 ** These macros are only available on Windows. They define the allowed values
5560 ** for the type argument to the [sqlite3_win32_set_directory] interface.
5562 #define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1
5563 #define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2
5566 ** CAPI3REF: Test For Auto-Commit Mode
5567 ** KEYWORDS: {autocommit mode}
5568 ** METHOD: sqlite3
5570 ** ^The sqlite3_get_autocommit() interface returns non-zero or
5571 ** zero if the given database connection is or is not in autocommit mode,
5572 ** respectively. ^Autocommit mode is on by default.
5573 ** ^Autocommit mode is disabled by a [BEGIN] statement.
5574 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
5576 ** If certain kinds of errors occur on a statement within a multi-statement
5577 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
5578 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
5579 ** transaction might be rolled back automatically. The only way to
5580 ** find out whether SQLite automatically rolled back the transaction after
5581 ** an error is to use this function.
5583 ** If another thread changes the autocommit status of the database
5584 ** connection while this routine is running, then the return value
5585 ** is undefined.
5587 int sqlite3_get_autocommit(sqlite3*);
5590 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
5591 ** METHOD: sqlite3_stmt
5593 ** ^The sqlite3_db_handle interface returns the [database connection] handle
5594 ** to which a [prepared statement] belongs. ^The [database connection]
5595 ** returned by sqlite3_db_handle is the same [database connection]
5596 ** that was the first argument
5597 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
5598 ** create the statement in the first place.
5600 sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
5603 ** CAPI3REF: Return The Filename For A Database Connection
5604 ** METHOD: sqlite3
5606 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
5607 ** associated with database N of connection D. ^The main database file
5608 ** has the name "main". If there is no attached database N on the database
5609 ** connection D, or if database N is a temporary or in-memory database, then
5610 ** a NULL pointer is returned.
5612 ** ^The filename returned by this function is the output of the
5613 ** xFullPathname method of the [VFS]. ^In other words, the filename
5614 ** will be an absolute pathname, even if the filename used
5615 ** to open the database originally was a URI or relative pathname.
5617 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
5620 ** CAPI3REF: Determine if a database is read-only
5621 ** METHOD: sqlite3
5623 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
5624 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
5625 ** the name of a database on connection D.
5627 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
5630 ** CAPI3REF: Find the next prepared statement
5631 ** METHOD: sqlite3
5633 ** ^This interface returns a pointer to the next [prepared statement] after
5634 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
5635 ** then this interface returns a pointer to the first prepared statement
5636 ** associated with the database connection pDb. ^If no prepared statement
5637 ** satisfies the conditions of this routine, it returns NULL.
5639 ** The [database connection] pointer D in a call to
5640 ** [sqlite3_next_stmt(D,S)] must refer to an open database
5641 ** connection and in particular must not be a NULL pointer.
5643 sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
5646 ** CAPI3REF: Commit And Rollback Notification Callbacks
5647 ** METHOD: sqlite3
5649 ** ^The sqlite3_commit_hook() interface registers a callback
5650 ** function to be invoked whenever a transaction is [COMMIT | committed].
5651 ** ^Any callback set by a previous call to sqlite3_commit_hook()
5652 ** for the same database connection is overridden.
5653 ** ^The sqlite3_rollback_hook() interface registers a callback
5654 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
5655 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
5656 ** for the same database connection is overridden.
5657 ** ^The pArg argument is passed through to the callback.
5658 ** ^If the callback on a commit hook function returns non-zero,
5659 ** then the commit is converted into a rollback.
5661 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
5662 ** return the P argument from the previous call of the same function
5663 ** on the same [database connection] D, or NULL for
5664 ** the first call for each function on D.
5666 ** The commit and rollback hook callbacks are not reentrant.
5667 ** The callback implementation must not do anything that will modify
5668 ** the database connection that invoked the callback. Any actions
5669 ** to modify the database connection must be deferred until after the
5670 ** completion of the [sqlite3_step()] call that triggered the commit
5671 ** or rollback hook in the first place.
5672 ** Note that running any other SQL statements, including SELECT statements,
5673 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
5674 ** the database connections for the meaning of "modify" in this paragraph.
5676 ** ^Registering a NULL function disables the callback.
5678 ** ^When the commit hook callback routine returns zero, the [COMMIT]
5679 ** operation is allowed to continue normally. ^If the commit hook
5680 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
5681 ** ^The rollback hook is invoked on a rollback that results from a commit
5682 ** hook returning non-zero, just as it would be with any other rollback.
5684 ** ^For the purposes of this API, a transaction is said to have been
5685 ** rolled back if an explicit "ROLLBACK" statement is executed, or
5686 ** an error or constraint causes an implicit rollback to occur.
5687 ** ^The rollback callback is not invoked if a transaction is
5688 ** automatically rolled back because the database connection is closed.
5690 ** See also the [sqlite3_update_hook()] interface.
5692 void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
5693 void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
5696 ** CAPI3REF: Data Change Notification Callbacks
5697 ** METHOD: sqlite3
5699 ** ^The sqlite3_update_hook() interface registers a callback function
5700 ** with the [database connection] identified by the first argument
5701 ** to be invoked whenever a row is updated, inserted or deleted in
5702 ** a [rowid table].
5703 ** ^Any callback set by a previous call to this function
5704 ** for the same database connection is overridden.
5706 ** ^The second argument is a pointer to the function to invoke when a
5707 ** row is updated, inserted or deleted in a rowid table.
5708 ** ^The first argument to the callback is a copy of the third argument
5709 ** to sqlite3_update_hook().
5710 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
5711 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
5712 ** to be invoked.
5713 ** ^The third and fourth arguments to the callback contain pointers to the
5714 ** database and table name containing the affected row.
5715 ** ^The final callback parameter is the [rowid] of the row.
5716 ** ^In the case of an update, this is the [rowid] after the update takes place.
5718 ** ^(The update hook is not invoked when internal system tables are
5719 ** modified (i.e. sqlite_master and sqlite_sequence).)^
5720 ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
5722 ** ^In the current implementation, the update hook
5723 ** is not invoked when conflicting rows are deleted because of an
5724 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
5725 ** invoked when rows are deleted using the [truncate optimization].
5726 ** The exceptions defined in this paragraph might change in a future
5727 ** release of SQLite.
5729 ** The update hook implementation must not do anything that will modify
5730 ** the database connection that invoked the update hook. Any actions
5731 ** to modify the database connection must be deferred until after the
5732 ** completion of the [sqlite3_step()] call that triggered the update hook.
5733 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
5734 ** database connections for the meaning of "modify" in this paragraph.
5736 ** ^The sqlite3_update_hook(D,C,P) function
5737 ** returns the P argument from the previous call
5738 ** on the same [database connection] D, or NULL for
5739 ** the first call on D.
5741 ** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
5742 ** and [sqlite3_preupdate_hook()] interfaces.
5744 void *sqlite3_update_hook(
5745 sqlite3*,
5746 void(*)(void *,int ,char const *,char const *,sqlite3_int64),
5747 void*
5751 ** CAPI3REF: Enable Or Disable Shared Pager Cache
5753 ** ^(This routine enables or disables the sharing of the database cache
5754 ** and schema data structures between [database connection | connections]
5755 ** to the same database. Sharing is enabled if the argument is true
5756 ** and disabled if the argument is false.)^
5758 ** ^Cache sharing is enabled and disabled for an entire process.
5759 ** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
5760 ** In prior versions of SQLite,
5761 ** sharing was enabled or disabled for each thread separately.
5763 ** ^(The cache sharing mode set by this interface effects all subsequent
5764 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
5765 ** Existing database connections continue use the sharing mode
5766 ** that was in effect at the time they were opened.)^
5768 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
5769 ** successfully. An [error code] is returned otherwise.)^
5771 ** ^Shared cache is disabled by default. But this might change in
5772 ** future releases of SQLite. Applications that care about shared
5773 ** cache setting should set it explicitly.
5775 ** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
5776 ** and will always return SQLITE_MISUSE. On those systems,
5777 ** shared cache mode should be enabled per-database connection via
5778 ** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
5780 ** This interface is threadsafe on processors where writing a
5781 ** 32-bit integer is atomic.
5783 ** See Also: [SQLite Shared-Cache Mode]
5785 int sqlite3_enable_shared_cache(int);
5788 ** CAPI3REF: Attempt To Free Heap Memory
5790 ** ^The sqlite3_release_memory() interface attempts to free N bytes
5791 ** of heap memory by deallocating non-essential memory allocations
5792 ** held by the database library. Memory used to cache database
5793 ** pages to improve performance is an example of non-essential memory.
5794 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
5795 ** which might be more or less than the amount requested.
5796 ** ^The sqlite3_release_memory() routine is a no-op returning zero
5797 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5799 ** See also: [sqlite3_db_release_memory()]
5801 int sqlite3_release_memory(int);
5804 ** CAPI3REF: Free Memory Used By A Database Connection
5805 ** METHOD: sqlite3
5807 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
5808 ** memory as possible from database connection D. Unlike the
5809 ** [sqlite3_release_memory()] interface, this interface is in effect even
5810 ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
5811 ** omitted.
5813 ** See also: [sqlite3_release_memory()]
5815 int sqlite3_db_release_memory(sqlite3*);
5818 ** CAPI3REF: Impose A Limit On Heap Size
5820 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
5821 ** soft limit on the amount of heap memory that may be allocated by SQLite.
5822 ** ^SQLite strives to keep heap memory utilization below the soft heap
5823 ** limit by reducing the number of pages held in the page cache
5824 ** as heap memory usages approaches the limit.
5825 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
5826 ** below the limit, it will exceed the limit rather than generate
5827 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
5828 ** is advisory only.
5830 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
5831 ** the soft heap limit prior to the call, or negative in the case of an
5832 ** error. ^If the argument N is negative
5833 ** then no change is made to the soft heap limit. Hence, the current
5834 ** size of the soft heap limit can be determined by invoking
5835 ** sqlite3_soft_heap_limit64() with a negative argument.
5837 ** ^If the argument N is zero then the soft heap limit is disabled.
5839 ** ^(The soft heap limit is not enforced in the current implementation
5840 ** if one or more of following conditions are true:
5842 ** <ul>
5843 ** <li> The soft heap limit is set to zero.
5844 ** <li> Memory accounting is disabled using a combination of the
5845 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
5846 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
5847 ** <li> An alternative page cache implementation is specified using
5848 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
5849 ** <li> The page cache allocates from its own memory pool supplied
5850 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
5851 ** from the heap.
5852 ** </ul>)^
5854 ** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]),
5855 ** the soft heap limit is enforced
5856 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
5857 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
5858 ** the soft heap limit is enforced on every memory allocation. Without
5859 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
5860 ** when memory is allocated by the page cache. Testing suggests that because
5861 ** the page cache is the predominate memory user in SQLite, most
5862 ** applications will achieve adequate soft heap limit enforcement without
5863 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5865 ** The circumstances under which SQLite will enforce the soft heap limit may
5866 ** changes in future releases of SQLite.
5868 sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
5871 ** CAPI3REF: Deprecated Soft Heap Limit Interface
5872 ** DEPRECATED
5874 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
5875 ** interface. This routine is provided for historical compatibility
5876 ** only. All new applications should use the
5877 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
5879 SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
5883 ** CAPI3REF: Extract Metadata About A Column Of A Table
5884 ** METHOD: sqlite3
5886 ** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
5887 ** information about column C of table T in database D
5888 ** on [database connection] X.)^ ^The sqlite3_table_column_metadata()
5889 ** interface returns SQLITE_OK and fills in the non-NULL pointers in
5890 ** the final five arguments with appropriate values if the specified
5891 ** column exists. ^The sqlite3_table_column_metadata() interface returns
5892 ** SQLITE_ERROR and if the specified column does not exist.
5893 ** ^If the column-name parameter to sqlite3_table_column_metadata() is a
5894 ** NULL pointer, then this routine simply checks for the existence of the
5895 ** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
5896 ** does not. If the table name parameter T in a call to
5897 ** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
5898 ** undefined behavior.
5900 ** ^The column is identified by the second, third and fourth parameters to
5901 ** this function. ^(The second parameter is either the name of the database
5902 ** (i.e. "main", "temp", or an attached database) containing the specified
5903 ** table or NULL.)^ ^If it is NULL, then all attached databases are searched
5904 ** for the table using the same algorithm used by the database engine to
5905 ** resolve unqualified table references.
5907 ** ^The third and fourth parameters to this function are the table and column
5908 ** name of the desired column, respectively.
5910 ** ^Metadata is returned by writing to the memory locations passed as the 5th
5911 ** and subsequent parameters to this function. ^Any of these arguments may be
5912 ** NULL, in which case the corresponding element of metadata is omitted.
5914 ** ^(<blockquote>
5915 ** <table border="1">
5916 ** <tr><th> Parameter <th> Output<br>Type <th> Description
5918 ** <tr><td> 5th <td> const char* <td> Data type
5919 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
5920 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
5921 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
5922 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
5923 ** </table>
5924 ** </blockquote>)^
5926 ** ^The memory pointed to by the character pointers returned for the
5927 ** declaration type and collation sequence is valid until the next
5928 ** call to any SQLite API function.
5930 ** ^If the specified table is actually a view, an [error code] is returned.
5932 ** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
5933 ** is not a [WITHOUT ROWID] table and an
5934 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
5935 ** parameters are set for the explicitly declared column. ^(If there is no
5936 ** [INTEGER PRIMARY KEY] column, then the outputs
5937 ** for the [rowid] are set as follows:
5939 ** <pre>
5940 ** data type: "INTEGER"
5941 ** collation sequence: "BINARY"
5942 ** not null: 0
5943 ** primary key: 1
5944 ** auto increment: 0
5945 ** </pre>)^
5947 ** ^This function causes all database schemas to be read from disk and
5948 ** parsed, if that has not already been done, and returns an error if
5949 ** any errors are encountered while loading the schema.
5951 int sqlite3_table_column_metadata(
5952 sqlite3 *db, /* Connection handle */
5953 const char *zDbName, /* Database name or NULL */
5954 const char *zTableName, /* Table name */
5955 const char *zColumnName, /* Column name */
5956 char const **pzDataType, /* OUTPUT: Declared data type */
5957 char const **pzCollSeq, /* OUTPUT: Collation sequence name */
5958 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
5959 int *pPrimaryKey, /* OUTPUT: True if column part of PK */
5960 int *pAutoinc /* OUTPUT: True if column is auto-increment */
5964 ** CAPI3REF: Load An Extension
5965 ** METHOD: sqlite3
5967 ** ^This interface loads an SQLite extension library from the named file.
5969 ** ^The sqlite3_load_extension() interface attempts to load an
5970 ** [SQLite extension] library contained in the file zFile. If
5971 ** the file cannot be loaded directly, attempts are made to load
5972 ** with various operating-system specific extensions added.
5973 ** So for example, if "samplelib" cannot be loaded, then names like
5974 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
5975 ** be tried also.
5977 ** ^The entry point is zProc.
5978 ** ^(zProc may be 0, in which case SQLite will try to come up with an
5979 ** entry point name on its own. It first tries "sqlite3_extension_init".
5980 ** If that does not work, it constructs a name "sqlite3_X_init" where the
5981 ** X is consists of the lower-case equivalent of all ASCII alphabetic
5982 ** characters in the filename from the last "/" to the first following
5983 ** "." and omitting any initial "lib".)^
5984 ** ^The sqlite3_load_extension() interface returns
5985 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
5986 ** ^If an error occurs and pzErrMsg is not 0, then the
5987 ** [sqlite3_load_extension()] interface shall attempt to
5988 ** fill *pzErrMsg with error message text stored in memory
5989 ** obtained from [sqlite3_malloc()]. The calling function
5990 ** should free this memory by calling [sqlite3_free()].
5992 ** ^Extension loading must be enabled using
5993 ** [sqlite3_enable_load_extension()] or
5994 ** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
5995 ** prior to calling this API,
5996 ** otherwise an error will be returned.
5998 ** <b>Security warning:</b> It is recommended that the
5999 ** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
6000 ** interface. The use of the [sqlite3_enable_load_extension()] interface
6001 ** should be avoided. This will keep the SQL function [load_extension()]
6002 ** disabled and prevent SQL injections from giving attackers
6003 ** access to extension loading capabilities.
6005 ** See also the [load_extension() SQL function].
6007 int sqlite3_load_extension(
6008 sqlite3 *db, /* Load the extension into this database connection */
6009 const char *zFile, /* Name of the shared library containing extension */
6010 const char *zProc, /* Entry point. Derived from zFile if 0 */
6011 char **pzErrMsg /* Put error message here if not 0 */
6015 ** CAPI3REF: Enable Or Disable Extension Loading
6016 ** METHOD: sqlite3
6018 ** ^So as not to open security holes in older applications that are
6019 ** unprepared to deal with [extension loading], and as a means of disabling
6020 ** [extension loading] while evaluating user-entered SQL, the following API
6021 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
6023 ** ^Extension loading is off by default.
6024 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
6025 ** to turn extension loading on and call it with onoff==0 to turn
6026 ** it back off again.
6028 ** ^This interface enables or disables both the C-API
6029 ** [sqlite3_load_extension()] and the SQL function [load_extension()].
6030 ** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
6031 ** to enable or disable only the C-API.)^
6033 ** <b>Security warning:</b> It is recommended that extension loading
6034 ** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
6035 ** rather than this interface, so the [load_extension()] SQL function
6036 ** remains disabled. This will prevent SQL injections from giving attackers
6037 ** access to extension loading capabilities.
6039 int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
6042 ** CAPI3REF: Automatically Load Statically Linked Extensions
6044 ** ^This interface causes the xEntryPoint() function to be invoked for
6045 ** each new [database connection] that is created. The idea here is that
6046 ** xEntryPoint() is the entry point for a statically linked [SQLite extension]
6047 ** that is to be automatically loaded into all new database connections.
6049 ** ^(Even though the function prototype shows that xEntryPoint() takes
6050 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
6051 ** arguments and expects an integer result as if the signature of the
6052 ** entry point where as follows:
6054 ** <blockquote><pre>
6055 ** &nbsp; int xEntryPoint(
6056 ** &nbsp; sqlite3 *db,
6057 ** &nbsp; const char **pzErrMsg,
6058 ** &nbsp; const struct sqlite3_api_routines *pThunk
6059 ** &nbsp; );
6060 ** </pre></blockquote>)^
6062 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
6063 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
6064 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
6065 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
6066 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
6067 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
6068 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
6070 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
6071 ** on the list of automatic extensions is a harmless no-op. ^No entry point
6072 ** will be called more than once for each database connection that is opened.
6074 ** See also: [sqlite3_reset_auto_extension()]
6075 ** and [sqlite3_cancel_auto_extension()]
6077 int sqlite3_auto_extension(void(*xEntryPoint)(void));
6080 ** CAPI3REF: Cancel Automatic Extension Loading
6082 ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
6083 ** initialization routine X that was registered using a prior call to
6084 ** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)]
6085 ** routine returns 1 if initialization routine X was successfully
6086 ** unregistered and it returns 0 if X was not on the list of initialization
6087 ** routines.
6089 int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
6092 ** CAPI3REF: Reset Automatic Extension Loading
6094 ** ^This interface disables all automatic extensions previously
6095 ** registered using [sqlite3_auto_extension()].
6097 void sqlite3_reset_auto_extension(void);
6100 ** The interface to the virtual-table mechanism is currently considered
6101 ** to be experimental. The interface might change in incompatible ways.
6102 ** If this is a problem for you, do not use the interface at this time.
6104 ** When the virtual-table mechanism stabilizes, we will declare the
6105 ** interface fixed, support it indefinitely, and remove this comment.
6109 ** Structures used by the virtual table interface
6111 typedef struct sqlite3_vtab sqlite3_vtab;
6112 typedef struct sqlite3_index_info sqlite3_index_info;
6113 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
6114 typedef struct sqlite3_module sqlite3_module;
6117 ** CAPI3REF: Virtual Table Object
6118 ** KEYWORDS: sqlite3_module {virtual table module}
6120 ** This structure, sometimes called a "virtual table module",
6121 ** defines the implementation of a [virtual tables].
6122 ** This structure consists mostly of methods for the module.
6124 ** ^A virtual table module is created by filling in a persistent
6125 ** instance of this structure and passing a pointer to that instance
6126 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
6127 ** ^The registration remains valid until it is replaced by a different
6128 ** module or until the [database connection] closes. The content
6129 ** of this structure must not change while it is registered with
6130 ** any database connection.
6132 struct sqlite3_module {
6133 int iVersion;
6134 int (*xCreate)(sqlite3*, void *pAux,
6135 int argc, const char *const*argv,
6136 sqlite3_vtab **ppVTab, char**);
6137 int (*xConnect)(sqlite3*, void *pAux,
6138 int argc, const char *const*argv,
6139 sqlite3_vtab **ppVTab, char**);
6140 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
6141 int (*xDisconnect)(sqlite3_vtab *pVTab);
6142 int (*xDestroy)(sqlite3_vtab *pVTab);
6143 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
6144 int (*xClose)(sqlite3_vtab_cursor*);
6145 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
6146 int argc, sqlite3_value **argv);
6147 int (*xNext)(sqlite3_vtab_cursor*);
6148 int (*xEof)(sqlite3_vtab_cursor*);
6149 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
6150 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
6151 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
6152 int (*xBegin)(sqlite3_vtab *pVTab);
6153 int (*xSync)(sqlite3_vtab *pVTab);
6154 int (*xCommit)(sqlite3_vtab *pVTab);
6155 int (*xRollback)(sqlite3_vtab *pVTab);
6156 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
6157 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
6158 void **ppArg);
6159 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
6160 /* The methods above are in version 1 of the sqlite_module object. Those
6161 ** below are for version 2 and greater. */
6162 int (*xSavepoint)(sqlite3_vtab *pVTab, int);
6163 int (*xRelease)(sqlite3_vtab *pVTab, int);
6164 int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
6168 ** CAPI3REF: Virtual Table Indexing Information
6169 ** KEYWORDS: sqlite3_index_info
6171 ** The sqlite3_index_info structure and its substructures is used as part
6172 ** of the [virtual table] interface to
6173 ** pass information into and receive the reply from the [xBestIndex]
6174 ** method of a [virtual table module]. The fields under **Inputs** are the
6175 ** inputs to xBestIndex and are read-only. xBestIndex inserts its
6176 ** results into the **Outputs** fields.
6178 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
6180 ** <blockquote>column OP expr</blockquote>
6182 ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^ ^(The particular operator is
6183 ** stored in aConstraint[].op using one of the
6184 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
6185 ** ^(The index of the column is stored in
6186 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
6187 ** expr on the right-hand side can be evaluated (and thus the constraint
6188 ** is usable) and false if it cannot.)^
6190 ** ^The optimizer automatically inverts terms of the form "expr OP column"
6191 ** and makes other simplifications to the WHERE clause in an attempt to
6192 ** get as many WHERE clause terms into the form shown above as possible.
6193 ** ^The aConstraint[] array only reports WHERE clause terms that are
6194 ** relevant to the particular virtual table being queried.
6196 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
6197 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
6199 ** The colUsed field indicates which columns of the virtual table may be
6200 ** required by the current scan. Virtual table columns are numbered from
6201 ** zero in the order in which they appear within the CREATE TABLE statement
6202 ** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
6203 ** the corresponding bit is set within the colUsed mask if the column may be
6204 ** required by SQLite. If the table has at least 64 columns and any column
6205 ** to the right of the first 63 is required, then bit 63 of colUsed is also
6206 ** set. In other words, column iCol may be required if the expression
6207 ** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
6208 ** non-zero.
6210 ** The [xBestIndex] method must fill aConstraintUsage[] with information
6211 ** about what parameters to pass to xFilter. ^If argvIndex>0 then
6212 ** the right-hand side of the corresponding aConstraint[] is evaluated
6213 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
6214 ** is true, then the constraint is assumed to be fully handled by the
6215 ** virtual table and is not checked again by SQLite.)^
6217 ** ^The idxNum and idxPtr values are recorded and passed into the
6218 ** [xFilter] method.
6219 ** ^[sqlite3_free()] is used to free idxPtr if and only if
6220 ** needToFreeIdxPtr is true.
6222 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
6223 ** the correct order to satisfy the ORDER BY clause so that no separate
6224 ** sorting step is required.
6226 ** ^The estimatedCost value is an estimate of the cost of a particular
6227 ** strategy. A cost of N indicates that the cost of the strategy is similar
6228 ** to a linear scan of an SQLite table with N rows. A cost of log(N)
6229 ** indicates that the expense of the operation is similar to that of a
6230 ** binary search on a unique indexed field of an SQLite table with N rows.
6232 ** ^The estimatedRows value is an estimate of the number of rows that
6233 ** will be returned by the strategy.
6235 ** The xBestIndex method may optionally populate the idxFlags field with a
6236 ** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
6237 ** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
6238 ** assumes that the strategy may visit at most one row.
6240 ** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
6241 ** SQLite also assumes that if a call to the xUpdate() method is made as
6242 ** part of the same statement to delete or update a virtual table row and the
6243 ** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
6244 ** any database changes. In other words, if the xUpdate() returns
6245 ** SQLITE_CONSTRAINT, the database contents must be exactly as they were
6246 ** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
6247 ** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
6248 ** the xUpdate method are automatically rolled back by SQLite.
6250 ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
6251 ** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
6252 ** If a virtual table extension is
6253 ** used with an SQLite version earlier than 3.8.2, the results of attempting
6254 ** to read or write the estimatedRows field are undefined (but are likely
6255 ** to included crashing the application). The estimatedRows field should
6256 ** therefore only be used if [sqlite3_libversion_number()] returns a
6257 ** value greater than or equal to 3008002. Similarly, the idxFlags field
6258 ** was added for [version 3.9.0] ([dateof:3.9.0]).
6259 ** It may therefore only be used if
6260 ** sqlite3_libversion_number() returns a value greater than or equal to
6261 ** 3009000.
6263 struct sqlite3_index_info {
6264 /* Inputs */
6265 int nConstraint; /* Number of entries in aConstraint */
6266 struct sqlite3_index_constraint {
6267 int iColumn; /* Column constrained. -1 for ROWID */
6268 unsigned char op; /* Constraint operator */
6269 unsigned char usable; /* True if this constraint is usable */
6270 int iTermOffset; /* Used internally - xBestIndex should ignore */
6271 } *aConstraint; /* Table of WHERE clause constraints */
6272 int nOrderBy; /* Number of terms in the ORDER BY clause */
6273 struct sqlite3_index_orderby {
6274 int iColumn; /* Column number */
6275 unsigned char desc; /* True for DESC. False for ASC. */
6276 } *aOrderBy; /* The ORDER BY clause */
6277 /* Outputs */
6278 struct sqlite3_index_constraint_usage {
6279 int argvIndex; /* if >0, constraint is part of argv to xFilter */
6280 unsigned char omit; /* Do not code a test for this constraint */
6281 } *aConstraintUsage;
6282 int idxNum; /* Number used to identify the index */
6283 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
6284 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
6285 int orderByConsumed; /* True if output is already ordered */
6286 double estimatedCost; /* Estimated cost of using this index */
6287 /* Fields below are only available in SQLite 3.8.2 and later */
6288 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */
6289 /* Fields below are only available in SQLite 3.9.0 and later */
6290 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */
6291 /* Fields below are only available in SQLite 3.10.0 and later */
6292 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */
6296 ** CAPI3REF: Virtual Table Scan Flags
6298 ** Virtual table implementations are allowed to set the
6299 ** [sqlite3_index_info].idxFlags field to some combination of
6300 ** these bits.
6302 #define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */
6305 ** CAPI3REF: Virtual Table Constraint Operator Codes
6307 ** These macros defined the allowed values for the
6308 ** [sqlite3_index_info].aConstraint[].op field. Each value represents
6309 ** an operator that is part of a constraint term in the wHERE clause of
6310 ** a query that uses a [virtual table].
6312 #define SQLITE_INDEX_CONSTRAINT_EQ 2
6313 #define SQLITE_INDEX_CONSTRAINT_GT 4
6314 #define SQLITE_INDEX_CONSTRAINT_LE 8
6315 #define SQLITE_INDEX_CONSTRAINT_LT 16
6316 #define SQLITE_INDEX_CONSTRAINT_GE 32
6317 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
6318 #define SQLITE_INDEX_CONSTRAINT_LIKE 65
6319 #define SQLITE_INDEX_CONSTRAINT_GLOB 66
6320 #define SQLITE_INDEX_CONSTRAINT_REGEXP 67
6321 #define SQLITE_INDEX_CONSTRAINT_NE 68
6322 #define SQLITE_INDEX_CONSTRAINT_ISNOT 69
6323 #define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70
6324 #define SQLITE_INDEX_CONSTRAINT_ISNULL 71
6325 #define SQLITE_INDEX_CONSTRAINT_IS 72
6328 ** CAPI3REF: Register A Virtual Table Implementation
6329 ** METHOD: sqlite3
6331 ** ^These routines are used to register a new [virtual table module] name.
6332 ** ^Module names must be registered before
6333 ** creating a new [virtual table] using the module and before using a
6334 ** preexisting [virtual table] for the module.
6336 ** ^The module name is registered on the [database connection] specified
6337 ** by the first parameter. ^The name of the module is given by the
6338 ** second parameter. ^The third parameter is a pointer to
6339 ** the implementation of the [virtual table module]. ^The fourth
6340 ** parameter is an arbitrary client data pointer that is passed through
6341 ** into the [xCreate] and [xConnect] methods of the virtual table module
6342 ** when a new virtual table is be being created or reinitialized.
6344 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
6345 ** is a pointer to a destructor for the pClientData. ^SQLite will
6346 ** invoke the destructor function (if it is not NULL) when SQLite
6347 ** no longer needs the pClientData pointer. ^The destructor will also
6348 ** be invoked if the call to sqlite3_create_module_v2() fails.
6349 ** ^The sqlite3_create_module()
6350 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
6351 ** destructor.
6353 int sqlite3_create_module(
6354 sqlite3 *db, /* SQLite connection to register module with */
6355 const char *zName, /* Name of the module */
6356 const sqlite3_module *p, /* Methods for the module */
6357 void *pClientData /* Client data for xCreate/xConnect */
6359 int sqlite3_create_module_v2(
6360 sqlite3 *db, /* SQLite connection to register module with */
6361 const char *zName, /* Name of the module */
6362 const sqlite3_module *p, /* Methods for the module */
6363 void *pClientData, /* Client data for xCreate/xConnect */
6364 void(*xDestroy)(void*) /* Module destructor function */
6368 ** CAPI3REF: Virtual Table Instance Object
6369 ** KEYWORDS: sqlite3_vtab
6371 ** Every [virtual table module] implementation uses a subclass
6372 ** of this object to describe a particular instance
6373 ** of the [virtual table]. Each subclass will
6374 ** be tailored to the specific needs of the module implementation.
6375 ** The purpose of this superclass is to define certain fields that are
6376 ** common to all module implementations.
6378 ** ^Virtual tables methods can set an error message by assigning a
6379 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
6380 ** take care that any prior string is freed by a call to [sqlite3_free()]
6381 ** prior to assigning a new string to zErrMsg. ^After the error message
6382 ** is delivered up to the client application, the string will be automatically
6383 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
6385 struct sqlite3_vtab {
6386 const sqlite3_module *pModule; /* The module for this virtual table */
6387 int nRef; /* Number of open cursors */
6388 char *zErrMsg; /* Error message from sqlite3_mprintf() */
6389 /* Virtual table implementations will typically add additional fields */
6393 ** CAPI3REF: Virtual Table Cursor Object
6394 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
6396 ** Every [virtual table module] implementation uses a subclass of the
6397 ** following structure to describe cursors that point into the
6398 ** [virtual table] and are used
6399 ** to loop through the virtual table. Cursors are created using the
6400 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
6401 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
6402 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
6403 ** of the module. Each module implementation will define
6404 ** the content of a cursor structure to suit its own needs.
6406 ** This superclass exists in order to define fields of the cursor that
6407 ** are common to all implementations.
6409 struct sqlite3_vtab_cursor {
6410 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
6411 /* Virtual table implementations will typically add additional fields */
6415 ** CAPI3REF: Declare The Schema Of A Virtual Table
6417 ** ^The [xCreate] and [xConnect] methods of a
6418 ** [virtual table module] call this interface
6419 ** to declare the format (the names and datatypes of the columns) of
6420 ** the virtual tables they implement.
6422 int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
6425 ** CAPI3REF: Overload A Function For A Virtual Table
6426 ** METHOD: sqlite3
6428 ** ^(Virtual tables can provide alternative implementations of functions
6429 ** using the [xFindFunction] method of the [virtual table module].
6430 ** But global versions of those functions
6431 ** must exist in order to be overloaded.)^
6433 ** ^(This API makes sure a global version of a function with a particular
6434 ** name and number of parameters exists. If no such function exists
6435 ** before this API is called, a new function is created.)^ ^The implementation
6436 ** of the new function always causes an exception to be thrown. So
6437 ** the new function is not good for anything by itself. Its only
6438 ** purpose is to be a placeholder function that can be overloaded
6439 ** by a [virtual table].
6441 int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
6444 ** The interface to the virtual-table mechanism defined above (back up
6445 ** to a comment remarkably similar to this one) is currently considered
6446 ** to be experimental. The interface might change in incompatible ways.
6447 ** If this is a problem for you, do not use the interface at this time.
6449 ** When the virtual-table mechanism stabilizes, we will declare the
6450 ** interface fixed, support it indefinitely, and remove this comment.
6454 ** CAPI3REF: A Handle To An Open BLOB
6455 ** KEYWORDS: {BLOB handle} {BLOB handles}
6457 ** An instance of this object represents an open BLOB on which
6458 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
6459 ** ^Objects of this type are created by [sqlite3_blob_open()]
6460 ** and destroyed by [sqlite3_blob_close()].
6461 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
6462 ** can be used to read or write small subsections of the BLOB.
6463 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
6465 typedef struct sqlite3_blob sqlite3_blob;
6468 ** CAPI3REF: Open A BLOB For Incremental I/O
6469 ** METHOD: sqlite3
6470 ** CONSTRUCTOR: sqlite3_blob
6472 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
6473 ** in row iRow, column zColumn, table zTable in database zDb;
6474 ** in other words, the same BLOB that would be selected by:
6476 ** <pre>
6477 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
6478 ** </pre>)^
6480 ** ^(Parameter zDb is not the filename that contains the database, but
6481 ** rather the symbolic name of the database. For attached databases, this is
6482 ** the name that appears after the AS keyword in the [ATTACH] statement.
6483 ** For the main database file, the database name is "main". For TEMP
6484 ** tables, the database name is "temp".)^
6486 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
6487 ** and write access. ^If the flags parameter is zero, the BLOB is opened for
6488 ** read-only access.
6490 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
6491 ** in *ppBlob. Otherwise an [error code] is returned and, unless the error
6492 ** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
6493 ** the API is not misused, it is always safe to call [sqlite3_blob_close()]
6494 ** on *ppBlob after this function it returns.
6496 ** This function fails with SQLITE_ERROR if any of the following are true:
6497 ** <ul>
6498 ** <li> ^(Database zDb does not exist)^,
6499 ** <li> ^(Table zTable does not exist within database zDb)^,
6500 ** <li> ^(Table zTable is a WITHOUT ROWID table)^,
6501 ** <li> ^(Column zColumn does not exist)^,
6502 ** <li> ^(Row iRow is not present in the table)^,
6503 ** <li> ^(The specified column of row iRow contains a value that is not
6504 ** a TEXT or BLOB value)^,
6505 ** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
6506 ** constraint and the blob is being opened for read/write access)^,
6507 ** <li> ^([foreign key constraints | Foreign key constraints] are enabled,
6508 ** column zColumn is part of a [child key] definition and the blob is
6509 ** being opened for read/write access)^.
6510 ** </ul>
6512 ** ^Unless it returns SQLITE_MISUSE, this function sets the
6513 ** [database connection] error code and message accessible via
6514 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6516 ** A BLOB referenced by sqlite3_blob_open() may be read using the
6517 ** [sqlite3_blob_read()] interface and modified by using
6518 ** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a
6519 ** different row of the same table using the [sqlite3_blob_reopen()]
6520 ** interface. However, the column, table, or database of a [BLOB handle]
6521 ** cannot be changed after the [BLOB handle] is opened.
6523 ** ^(If the row that a BLOB handle points to is modified by an
6524 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
6525 ** then the BLOB handle is marked as "expired".
6526 ** This is true if any column of the row is changed, even a column
6527 ** other than the one the BLOB handle is open on.)^
6528 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
6529 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
6530 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
6531 ** rolled back by the expiration of the BLOB. Such changes will eventually
6532 ** commit if the transaction continues to completion.)^
6534 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
6535 ** the opened blob. ^The size of a blob may not be changed by this
6536 ** interface. Use the [UPDATE] SQL command to change the size of a
6537 ** blob.
6539 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
6540 ** and the built-in [zeroblob] SQL function may be used to create a
6541 ** zero-filled blob to read or write using the incremental-blob interface.
6543 ** To avoid a resource leak, every open [BLOB handle] should eventually
6544 ** be released by a call to [sqlite3_blob_close()].
6546 ** See also: [sqlite3_blob_close()],
6547 ** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
6548 ** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
6550 int sqlite3_blob_open(
6551 sqlite3*,
6552 const char *zDb,
6553 const char *zTable,
6554 const char *zColumn,
6555 sqlite3_int64 iRow,
6556 int flags,
6557 sqlite3_blob **ppBlob
6561 ** CAPI3REF: Move a BLOB Handle to a New Row
6562 ** METHOD: sqlite3_blob
6564 ** ^This function is used to move an existing [BLOB handle] so that it points
6565 ** to a different row of the same database table. ^The new row is identified
6566 ** by the rowid value passed as the second argument. Only the row can be
6567 ** changed. ^The database, table and column on which the blob handle is open
6568 ** remain the same. Moving an existing [BLOB handle] to a new row is
6569 ** faster than closing the existing handle and opening a new one.
6571 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
6572 ** it must exist and there must be either a blob or text value stored in
6573 ** the nominated column.)^ ^If the new row is not present in the table, or if
6574 ** it does not contain a blob or text value, or if another error occurs, an
6575 ** SQLite error code is returned and the blob handle is considered aborted.
6576 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
6577 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
6578 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
6579 ** always returns zero.
6581 ** ^This function sets the database handle error code and message.
6583 int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
6586 ** CAPI3REF: Close A BLOB Handle
6587 ** DESTRUCTOR: sqlite3_blob
6589 ** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
6590 ** unconditionally. Even if this routine returns an error code, the
6591 ** handle is still closed.)^
6593 ** ^If the blob handle being closed was opened for read-write access, and if
6594 ** the database is in auto-commit mode and there are no other open read-write
6595 ** blob handles or active write statements, the current transaction is
6596 ** committed. ^If an error occurs while committing the transaction, an error
6597 ** code is returned and the transaction rolled back.
6599 ** Calling this function with an argument that is not a NULL pointer or an
6600 ** open blob handle results in undefined behaviour. ^Calling this routine
6601 ** with a null pointer (such as would be returned by a failed call to
6602 ** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
6603 ** is passed a valid open blob handle, the values returned by the
6604 ** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
6606 int sqlite3_blob_close(sqlite3_blob *);
6609 ** CAPI3REF: Return The Size Of An Open BLOB
6610 ** METHOD: sqlite3_blob
6612 ** ^Returns the size in bytes of the BLOB accessible via the
6613 ** successfully opened [BLOB handle] in its only argument. ^The
6614 ** incremental blob I/O routines can only read or overwriting existing
6615 ** blob content; they cannot change the size of a blob.
6617 ** This routine only works on a [BLOB handle] which has been created
6618 ** by a prior successful call to [sqlite3_blob_open()] and which has not
6619 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6620 ** to this routine results in undefined and probably undesirable behavior.
6622 int sqlite3_blob_bytes(sqlite3_blob *);
6625 ** CAPI3REF: Read Data From A BLOB Incrementally
6626 ** METHOD: sqlite3_blob
6628 ** ^(This function is used to read data from an open [BLOB handle] into a
6629 ** caller-supplied buffer. N bytes of data are copied into buffer Z
6630 ** from the open BLOB, starting at offset iOffset.)^
6632 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
6633 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
6634 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
6635 ** ^The size of the blob (and hence the maximum value of N+iOffset)
6636 ** can be determined using the [sqlite3_blob_bytes()] interface.
6638 ** ^An attempt to read from an expired [BLOB handle] fails with an
6639 ** error code of [SQLITE_ABORT].
6641 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
6642 ** Otherwise, an [error code] or an [extended error code] is returned.)^
6644 ** This routine only works on a [BLOB handle] which has been created
6645 ** by a prior successful call to [sqlite3_blob_open()] and which has not
6646 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6647 ** to this routine results in undefined and probably undesirable behavior.
6649 ** See also: [sqlite3_blob_write()].
6651 int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
6654 ** CAPI3REF: Write Data Into A BLOB Incrementally
6655 ** METHOD: sqlite3_blob
6657 ** ^(This function is used to write data into an open [BLOB handle] from a
6658 ** caller-supplied buffer. N bytes of data are copied from the buffer Z
6659 ** into the open BLOB, starting at offset iOffset.)^
6661 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
6662 ** Otherwise, an [error code] or an [extended error code] is returned.)^
6663 ** ^Unless SQLITE_MISUSE is returned, this function sets the
6664 ** [database connection] error code and message accessible via
6665 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6667 ** ^If the [BLOB handle] passed as the first argument was not opened for
6668 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
6669 ** this function returns [SQLITE_READONLY].
6671 ** This function may only modify the contents of the BLOB; it is
6672 ** not possible to increase the size of a BLOB using this API.
6673 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
6674 ** [SQLITE_ERROR] is returned and no data is written. The size of the
6675 ** BLOB (and hence the maximum value of N+iOffset) can be determined
6676 ** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
6677 ** than zero [SQLITE_ERROR] is returned and no data is written.
6679 ** ^An attempt to write to an expired [BLOB handle] fails with an
6680 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
6681 ** before the [BLOB handle] expired are not rolled back by the
6682 ** expiration of the handle, though of course those changes might
6683 ** have been overwritten by the statement that expired the BLOB handle
6684 ** or by other independent statements.
6686 ** This routine only works on a [BLOB handle] which has been created
6687 ** by a prior successful call to [sqlite3_blob_open()] and which has not
6688 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6689 ** to this routine results in undefined and probably undesirable behavior.
6691 ** See also: [sqlite3_blob_read()].
6693 int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
6696 ** CAPI3REF: Virtual File System Objects
6698 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
6699 ** that SQLite uses to interact
6700 ** with the underlying operating system. Most SQLite builds come with a
6701 ** single default VFS that is appropriate for the host computer.
6702 ** New VFSes can be registered and existing VFSes can be unregistered.
6703 ** The following interfaces are provided.
6705 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
6706 ** ^Names are case sensitive.
6707 ** ^Names are zero-terminated UTF-8 strings.
6708 ** ^If there is no match, a NULL pointer is returned.
6709 ** ^If zVfsName is NULL then the default VFS is returned.
6711 ** ^New VFSes are registered with sqlite3_vfs_register().
6712 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
6713 ** ^The same VFS can be registered multiple times without injury.
6714 ** ^To make an existing VFS into the default VFS, register it again
6715 ** with the makeDflt flag set. If two different VFSes with the
6716 ** same name are registered, the behavior is undefined. If a
6717 ** VFS is registered with a name that is NULL or an empty string,
6718 ** then the behavior is undefined.
6720 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
6721 ** ^(If the default VFS is unregistered, another VFS is chosen as
6722 ** the default. The choice for the new VFS is arbitrary.)^
6724 sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
6725 int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
6726 int sqlite3_vfs_unregister(sqlite3_vfs*);
6729 ** CAPI3REF: Mutexes
6731 ** The SQLite core uses these routines for thread
6732 ** synchronization. Though they are intended for internal
6733 ** use by SQLite, code that links against SQLite is
6734 ** permitted to use any of these routines.
6736 ** The SQLite source code contains multiple implementations
6737 ** of these mutex routines. An appropriate implementation
6738 ** is selected automatically at compile-time. The following
6739 ** implementations are available in the SQLite core:
6741 ** <ul>
6742 ** <li> SQLITE_MUTEX_PTHREADS
6743 ** <li> SQLITE_MUTEX_W32
6744 ** <li> SQLITE_MUTEX_NOOP
6745 ** </ul>
6747 ** The SQLITE_MUTEX_NOOP implementation is a set of routines
6748 ** that does no real locking and is appropriate for use in
6749 ** a single-threaded application. The SQLITE_MUTEX_PTHREADS and
6750 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
6751 ** and Windows.
6753 ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
6754 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
6755 ** implementation is included with the library. In this case the
6756 ** application must supply a custom mutex implementation using the
6757 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
6758 ** before calling sqlite3_initialize() or any other public sqlite3_
6759 ** function that calls sqlite3_initialize().
6761 ** ^The sqlite3_mutex_alloc() routine allocates a new
6762 ** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
6763 ** routine returns NULL if it is unable to allocate the requested
6764 ** mutex. The argument to sqlite3_mutex_alloc() must one of these
6765 ** integer constants:
6767 ** <ul>
6768 ** <li> SQLITE_MUTEX_FAST
6769 ** <li> SQLITE_MUTEX_RECURSIVE
6770 ** <li> SQLITE_MUTEX_STATIC_MASTER
6771 ** <li> SQLITE_MUTEX_STATIC_MEM
6772 ** <li> SQLITE_MUTEX_STATIC_OPEN
6773 ** <li> SQLITE_MUTEX_STATIC_PRNG
6774 ** <li> SQLITE_MUTEX_STATIC_LRU
6775 ** <li> SQLITE_MUTEX_STATIC_PMEM
6776 ** <li> SQLITE_MUTEX_STATIC_APP1
6777 ** <li> SQLITE_MUTEX_STATIC_APP2
6778 ** <li> SQLITE_MUTEX_STATIC_APP3
6779 ** <li> SQLITE_MUTEX_STATIC_VFS1
6780 ** <li> SQLITE_MUTEX_STATIC_VFS2
6781 ** <li> SQLITE_MUTEX_STATIC_VFS3
6782 ** </ul>
6784 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
6785 ** cause sqlite3_mutex_alloc() to create
6786 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
6787 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
6788 ** The mutex implementation does not need to make a distinction
6789 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
6790 ** not want to. SQLite will only request a recursive mutex in
6791 ** cases where it really needs one. If a faster non-recursive mutex
6792 ** implementation is available on the host platform, the mutex subsystem
6793 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
6795 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
6796 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
6797 ** a pointer to a static preexisting mutex. ^Nine static mutexes are
6798 ** used by the current version of SQLite. Future versions of SQLite
6799 ** may add additional static mutexes. Static mutexes are for internal
6800 ** use by SQLite only. Applications that use SQLite mutexes should
6801 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
6802 ** SQLITE_MUTEX_RECURSIVE.
6804 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
6805 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
6806 ** returns a different mutex on every call. ^For the static
6807 ** mutex types, the same mutex is returned on every call that has
6808 ** the same type number.
6810 ** ^The sqlite3_mutex_free() routine deallocates a previously
6811 ** allocated dynamic mutex. Attempting to deallocate a static
6812 ** mutex results in undefined behavior.
6814 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
6815 ** to enter a mutex. ^If another thread is already within the mutex,
6816 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
6817 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
6818 ** upon successful entry. ^(Mutexes created using
6819 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
6820 ** In such cases, the
6821 ** mutex must be exited an equal number of times before another thread
6822 ** can enter.)^ If the same thread tries to enter any mutex other
6823 ** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
6825 ** ^(Some systems (for example, Windows 95) do not support the operation
6826 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
6827 ** will always return SQLITE_BUSY. The SQLite core only ever uses
6828 ** sqlite3_mutex_try() as an optimization so this is acceptable
6829 ** behavior.)^
6831 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
6832 ** previously entered by the same thread. The behavior
6833 ** is undefined if the mutex is not currently entered by the
6834 ** calling thread or is not currently allocated.
6836 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
6837 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
6838 ** behave as no-ops.
6840 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
6842 sqlite3_mutex *sqlite3_mutex_alloc(int);
6843 void sqlite3_mutex_free(sqlite3_mutex*);
6844 void sqlite3_mutex_enter(sqlite3_mutex*);
6845 int sqlite3_mutex_try(sqlite3_mutex*);
6846 void sqlite3_mutex_leave(sqlite3_mutex*);
6849 ** CAPI3REF: Mutex Methods Object
6851 ** An instance of this structure defines the low-level routines
6852 ** used to allocate and use mutexes.
6854 ** Usually, the default mutex implementations provided by SQLite are
6855 ** sufficient, however the application has the option of substituting a custom
6856 ** implementation for specialized deployments or systems for which SQLite
6857 ** does not provide a suitable implementation. In this case, the application
6858 ** creates and populates an instance of this structure to pass
6859 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
6860 ** Additionally, an instance of this structure can be used as an
6861 ** output variable when querying the system for the current mutex
6862 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
6864 ** ^The xMutexInit method defined by this structure is invoked as
6865 ** part of system initialization by the sqlite3_initialize() function.
6866 ** ^The xMutexInit routine is called by SQLite exactly once for each
6867 ** effective call to [sqlite3_initialize()].
6869 ** ^The xMutexEnd method defined by this structure is invoked as
6870 ** part of system shutdown by the sqlite3_shutdown() function. The
6871 ** implementation of this method is expected to release all outstanding
6872 ** resources obtained by the mutex methods implementation, especially
6873 ** those obtained by the xMutexInit method. ^The xMutexEnd()
6874 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
6876 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
6877 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
6878 ** xMutexNotheld) implement the following interfaces (respectively):
6880 ** <ul>
6881 ** <li> [sqlite3_mutex_alloc()] </li>
6882 ** <li> [sqlite3_mutex_free()] </li>
6883 ** <li> [sqlite3_mutex_enter()] </li>
6884 ** <li> [sqlite3_mutex_try()] </li>
6885 ** <li> [sqlite3_mutex_leave()] </li>
6886 ** <li> [sqlite3_mutex_held()] </li>
6887 ** <li> [sqlite3_mutex_notheld()] </li>
6888 ** </ul>)^
6890 ** The only difference is that the public sqlite3_XXX functions enumerated
6891 ** above silently ignore any invocations that pass a NULL pointer instead
6892 ** of a valid mutex handle. The implementations of the methods defined
6893 ** by this structure are not required to handle this case, the results
6894 ** of passing a NULL pointer instead of a valid mutex handle are undefined
6895 ** (i.e. it is acceptable to provide an implementation that segfaults if
6896 ** it is passed a NULL pointer).
6898 ** The xMutexInit() method must be threadsafe. It must be harmless to
6899 ** invoke xMutexInit() multiple times within the same process and without
6900 ** intervening calls to xMutexEnd(). Second and subsequent calls to
6901 ** xMutexInit() must be no-ops.
6903 ** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
6904 ** and its associates). Similarly, xMutexAlloc() must not use SQLite memory
6905 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
6906 ** memory allocation for a fast or recursive mutex.
6908 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
6909 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
6910 ** If xMutexInit fails in any way, it is expected to clean up after itself
6911 ** prior to returning.
6913 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
6914 struct sqlite3_mutex_methods {
6915 int (*xMutexInit)(void);
6916 int (*xMutexEnd)(void);
6917 sqlite3_mutex *(*xMutexAlloc)(int);
6918 void (*xMutexFree)(sqlite3_mutex *);
6919 void (*xMutexEnter)(sqlite3_mutex *);
6920 int (*xMutexTry)(sqlite3_mutex *);
6921 void (*xMutexLeave)(sqlite3_mutex *);
6922 int (*xMutexHeld)(sqlite3_mutex *);
6923 int (*xMutexNotheld)(sqlite3_mutex *);
6927 ** CAPI3REF: Mutex Verification Routines
6929 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
6930 ** are intended for use inside assert() statements. The SQLite core
6931 ** never uses these routines except inside an assert() and applications
6932 ** are advised to follow the lead of the core. The SQLite core only
6933 ** provides implementations for these routines when it is compiled
6934 ** with the SQLITE_DEBUG flag. External mutex implementations
6935 ** are only required to provide these routines if SQLITE_DEBUG is
6936 ** defined and if NDEBUG is not defined.
6938 ** These routines should return true if the mutex in their argument
6939 ** is held or not held, respectively, by the calling thread.
6941 ** The implementation is not required to provide versions of these
6942 ** routines that actually work. If the implementation does not provide working
6943 ** versions of these routines, it should at least provide stubs that always
6944 ** return true so that one does not get spurious assertion failures.
6946 ** If the argument to sqlite3_mutex_held() is a NULL pointer then
6947 ** the routine should return 1. This seems counter-intuitive since
6948 ** clearly the mutex cannot be held if it does not exist. But
6949 ** the reason the mutex does not exist is because the build is not
6950 ** using mutexes. And we do not want the assert() containing the
6951 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
6952 ** the appropriate thing to do. The sqlite3_mutex_notheld()
6953 ** interface should also return 1 when given a NULL pointer.
6955 #ifndef NDEBUG
6956 int sqlite3_mutex_held(sqlite3_mutex*);
6957 int sqlite3_mutex_notheld(sqlite3_mutex*);
6958 #endif
6961 ** CAPI3REF: Mutex Types
6963 ** The [sqlite3_mutex_alloc()] interface takes a single argument
6964 ** which is one of these integer constants.
6966 ** The set of static mutexes may change from one SQLite release to the
6967 ** next. Applications that override the built-in mutex logic must be
6968 ** prepared to accommodate additional static mutexes.
6970 #define SQLITE_MUTEX_FAST 0
6971 #define SQLITE_MUTEX_RECURSIVE 1
6972 #define SQLITE_MUTEX_STATIC_MASTER 2
6973 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
6974 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
6975 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
6976 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */
6977 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
6978 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
6979 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
6980 #define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */
6981 #define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */
6982 #define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */
6983 #define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */
6984 #define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */
6985 #define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */
6988 ** CAPI3REF: Retrieve the mutex for a database connection
6989 ** METHOD: sqlite3
6991 ** ^This interface returns a pointer the [sqlite3_mutex] object that
6992 ** serializes access to the [database connection] given in the argument
6993 ** when the [threading mode] is Serialized.
6994 ** ^If the [threading mode] is Single-thread or Multi-thread then this
6995 ** routine returns a NULL pointer.
6997 sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
7000 ** CAPI3REF: Low-Level Control Of Database Files
7001 ** METHOD: sqlite3
7003 ** ^The [sqlite3_file_control()] interface makes a direct call to the
7004 ** xFileControl method for the [sqlite3_io_methods] object associated
7005 ** with a particular database identified by the second argument. ^The
7006 ** name of the database is "main" for the main database or "temp" for the
7007 ** TEMP database, or the name that appears after the AS keyword for
7008 ** databases that are added using the [ATTACH] SQL command.
7009 ** ^A NULL pointer can be used in place of "main" to refer to the
7010 ** main database file.
7011 ** ^The third and fourth parameters to this routine
7012 ** are passed directly through to the second and third parameters of
7013 ** the xFileControl method. ^The return value of the xFileControl
7014 ** method becomes the return value of this routine.
7016 ** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
7017 ** a pointer to the underlying [sqlite3_file] object to be written into
7018 ** the space pointed to by the 4th parameter. ^The [SQLITE_FCNTL_FILE_POINTER]
7019 ** case is a short-circuit path which does not actually invoke the
7020 ** underlying sqlite3_io_methods.xFileControl method.
7022 ** ^If the second parameter (zDbName) does not match the name of any
7023 ** open database file, then SQLITE_ERROR is returned. ^This error
7024 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
7025 ** or [sqlite3_errmsg()]. The underlying xFileControl method might
7026 ** also return SQLITE_ERROR. There is no way to distinguish between
7027 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
7028 ** xFileControl method.
7030 ** See also: [file control opcodes]
7032 int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
7035 ** CAPI3REF: Testing Interface
7037 ** ^The sqlite3_test_control() interface is used to read out internal
7038 ** state of SQLite and to inject faults into SQLite for testing
7039 ** purposes. ^The first parameter is an operation code that determines
7040 ** the number, meaning, and operation of all subsequent parameters.
7042 ** This interface is not for use by applications. It exists solely
7043 ** for verifying the correct operation of the SQLite library. Depending
7044 ** on how the SQLite library is compiled, this interface might not exist.
7046 ** The details of the operation codes, their meanings, the parameters
7047 ** they take, and what they do are all subject to change without notice.
7048 ** Unlike most of the SQLite API, this function is not guaranteed to
7049 ** operate consistently from one release to the next.
7051 int sqlite3_test_control(int op, ...);
7054 ** CAPI3REF: Testing Interface Operation Codes
7056 ** These constants are the valid operation code parameters used
7057 ** as the first argument to [sqlite3_test_control()].
7059 ** These parameters and their meanings are subject to change
7060 ** without notice. These values are for testing purposes only.
7061 ** Applications should not use any of these parameters or the
7062 ** [sqlite3_test_control()] interface.
7064 #define SQLITE_TESTCTRL_FIRST 5
7065 #define SQLITE_TESTCTRL_PRNG_SAVE 5
7066 #define SQLITE_TESTCTRL_PRNG_RESTORE 6
7067 #define SQLITE_TESTCTRL_PRNG_RESET 7
7068 #define SQLITE_TESTCTRL_BITVEC_TEST 8
7069 #define SQLITE_TESTCTRL_FAULT_INSTALL 9
7070 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
7071 #define SQLITE_TESTCTRL_PENDING_BYTE 11
7072 #define SQLITE_TESTCTRL_ASSERT 12
7073 #define SQLITE_TESTCTRL_ALWAYS 13
7074 #define SQLITE_TESTCTRL_RESERVE 14
7075 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
7076 #define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */
7077 #define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */
7078 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
7079 #define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */
7080 #define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19
7081 #define SQLITE_TESTCTRL_NEVER_CORRUPT 20
7082 #define SQLITE_TESTCTRL_VDBE_COVERAGE 21
7083 #define SQLITE_TESTCTRL_BYTEORDER 22
7084 #define SQLITE_TESTCTRL_ISINIT 23
7085 #define SQLITE_TESTCTRL_SORTER_MMAP 24
7086 #define SQLITE_TESTCTRL_IMPOSTER 25
7087 #define SQLITE_TESTCTRL_PARSER_COVERAGE 26
7088 #define SQLITE_TESTCTRL_LAST 26 /* Largest TESTCTRL */
7091 ** CAPI3REF: SQL Keyword Checking
7093 ** These routines provide access to the set of SQL language keywords
7094 ** recognized by SQLite. Applications can uses these routines to determine
7095 ** whether or not a specific identifier needs to be escaped (for example,
7096 ** by enclosing in double-quotes) so as not to confuse the parser.
7098 ** The sqlite3_keyword_count() interface returns the number of distinct
7099 ** keywords understood by SQLite.
7101 ** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and
7102 ** makes *Z point to that keyword expressed as UTF8 and writes the number
7103 ** of bytes in the keyword into *L. The string that *Z points to is not
7104 ** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns
7105 ** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
7106 ** or L are NULL or invalid pointers then calls to
7107 ** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
7109 ** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
7110 ** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
7111 ** if it is and zero if not.
7113 ** The parser used by SQLite is forgiving. It is often possible to use
7114 ** a keyword as an identifier as long as such use does not result in a
7115 ** parsing ambiguity. For example, the statement
7116 ** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
7117 ** creates a new table named "BEGIN" with three columns named
7118 ** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid
7119 ** using keywords as identifiers. Common techniques used to avoid keyword
7120 ** name collisions include:
7121 ** <ul>
7122 ** <li> Put all identifier names inside double-quotes. This is the official
7123 ** SQL way to escape identifier names.
7124 ** <li> Put identifier names inside &#91;...&#93;. This is not standard SQL,
7125 ** but it is what SQL Server does and so lots of programmers use this
7126 ** technique.
7127 ** <li> Begin every identifier with the letter "Z" as no SQL keywords start
7128 ** with "Z".
7129 ** <li> Include a digit somewhere in every identifier name.
7130 ** </ul>
7132 ** Note that the number of keywords understood by SQLite can depend on
7133 ** compile-time options. For example, "VACUUM" is not a keyword if
7134 ** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also,
7135 ** new keywords may be added to future releases of SQLite.
7137 int sqlite3_keyword_count(void);
7138 int sqlite3_keyword_name(int,const char**,int*);
7139 int sqlite3_keyword_check(const char*,int);
7142 ** CAPI3REF: Dynamic String Object
7143 ** KEYWORDS: {dynamic string}
7145 ** An instance of the sqlite3_str object contains a dynamically-sized
7146 ** string under construction.
7148 ** The lifecycle of an sqlite3_str object is as follows:
7149 ** <ol>
7150 ** <li> ^The sqlite3_str object is created using [sqlite3_str_new()].
7151 ** <li> ^Text is appended to the sqlite3_str object using various
7152 ** methods, such as [sqlite3_str_appendf()].
7153 ** <li> ^The sqlite3_str object is destroyed and the string it created
7154 ** is returned using the [sqlite3_str_finish()] interface.
7155 ** </ol>
7157 typedef struct sqlite3_str sqlite3_str;
7160 ** CAPI3REF: Create A New Dynamic String Object
7161 ** CONSTRUCTOR: sqlite3_str
7163 ** ^The [sqlite3_str_new(D)] interface allocates and initializes
7164 ** a new [sqlite3_str] object. To avoid memory leaks, the object returned by
7165 ** [sqlite3_str_new()] must be freed by a subsequent call to
7166 ** [sqlite3_str_finish(X)].
7168 ** ^The [sqlite3_str_new(D)] interface always returns a pointer to a
7169 ** valid [sqlite3_str] object, though in the event of an out-of-memory
7170 ** error the returned object might be a special singleton that will
7171 ** silently reject new text, always return SQLITE_NOMEM from
7172 ** [sqlite3_str_errcode()], always return 0 for
7173 ** [sqlite3_str_length()], and always return NULL from
7174 ** [sqlite3_str_finish(X)]. It is always safe to use the value
7175 ** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter
7176 ** to any of the other [sqlite3_str] methods.
7178 ** The D parameter to [sqlite3_str_new(D)] may be NULL. If the
7179 ** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum
7180 ** length of the string contained in the [sqlite3_str] object will be
7181 ** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead
7182 ** of [SQLITE_MAX_LENGTH].
7184 sqlite3_str *sqlite3_str_new(sqlite3*);
7187 ** CAPI3REF: Finalize A Dynamic String
7188 ** DESTRUCTOR: sqlite3_str
7190 ** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
7191 ** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
7192 ** that contains the constructed string. The calling application should
7193 ** pass the returned value to [sqlite3_free()] to avoid a memory leak.
7194 ** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
7195 ** errors were encountered during construction of the string. ^The
7196 ** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the
7197 ** string in [sqlite3_str] object X is zero bytes long.
7199 char *sqlite3_str_finish(sqlite3_str*);
7202 ** CAPI3REF: Add Content To A Dynamic String
7203 ** METHOD: sqlite3_str
7205 ** These interfaces add content to an sqlite3_str object previously obtained
7206 ** from [sqlite3_str_new()].
7208 ** ^The [sqlite3_str_appendf(X,F,...)] and
7209 ** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
7210 ** functionality of SQLite to append formatted text onto the end of
7211 ** [sqlite3_str] object X.
7213 ** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
7214 ** onto the end of the [sqlite3_str] object X. N must be non-negative.
7215 ** S must contain at least N non-zero bytes of content. To append a
7216 ** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
7217 ** method instead.
7219 ** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of
7220 ** zero-terminated string S onto the end of [sqlite3_str] object X.
7222 ** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
7223 ** single-byte character C onto the end of [sqlite3_str] object X.
7224 ** ^This method can be used, for example, to add whitespace indentation.
7226 ** ^The [sqlite3_str_reset(X)] method resets the string under construction
7227 ** inside [sqlite3_str] object X back to zero bytes in length.
7229 ** These methods do not return a result code. ^If an error occurs, that fact
7230 ** is recorded in the [sqlite3_str] object and can be recovered by a
7231 ** subsequent call to [sqlite3_str_errcode(X)].
7233 void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
7234 void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
7235 void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
7236 void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
7237 void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
7238 void sqlite3_str_reset(sqlite3_str*);
7241 ** CAPI3REF: Status Of A Dynamic String
7242 ** METHOD: sqlite3_str
7244 ** These interfaces return the current status of an [sqlite3_str] object.
7246 ** ^If any prior errors have occurred while constructing the dynamic string
7247 ** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
7248 ** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns
7249 ** [SQLITE_NOMEM] following any out-of-memory error, or
7250 ** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
7251 ** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
7253 ** ^The [sqlite3_str_length(X)] method returns the current length, in bytes,
7254 ** of the dynamic string under construction in [sqlite3_str] object X.
7255 ** ^The length returned by [sqlite3_str_length(X)] does not include the
7256 ** zero-termination byte.
7258 ** ^The [sqlite3_str_value(X)] method returns a pointer to the current
7259 ** content of the dynamic string under construction in X. The value
7260 ** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
7261 ** and might be freed or altered by any subsequent method on the same
7262 ** [sqlite3_str] object. Applications must not used the pointer returned
7263 ** [sqlite3_str_value(X)] after any subsequent method call on the same
7264 ** object. ^Applications may change the content of the string returned
7265 ** by [sqlite3_str_value(X)] as long as they do not write into any bytes
7266 ** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
7267 ** write any byte after any subsequent sqlite3_str method call.
7269 int sqlite3_str_errcode(sqlite3_str*);
7270 int sqlite3_str_length(sqlite3_str*);
7271 char *sqlite3_str_value(sqlite3_str*);
7274 ** CAPI3REF: SQLite Runtime Status
7276 ** ^These interfaces are used to retrieve runtime status information
7277 ** about the performance of SQLite, and optionally to reset various
7278 ** highwater marks. ^The first argument is an integer code for
7279 ** the specific parameter to measure. ^(Recognized integer codes
7280 ** are of the form [status parameters | SQLITE_STATUS_...].)^
7281 ** ^The current value of the parameter is returned into *pCurrent.
7282 ** ^The highest recorded value is returned in *pHighwater. ^If the
7283 ** resetFlag is true, then the highest record value is reset after
7284 ** *pHighwater is written. ^(Some parameters do not record the highest
7285 ** value. For those parameters
7286 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
7287 ** ^(Other parameters record only the highwater mark and not the current
7288 ** value. For these latter parameters nothing is written into *pCurrent.)^
7290 ** ^The sqlite3_status() and sqlite3_status64() routines return
7291 ** SQLITE_OK on success and a non-zero [error code] on failure.
7293 ** If either the current value or the highwater mark is too large to
7294 ** be represented by a 32-bit integer, then the values returned by
7295 ** sqlite3_status() are undefined.
7297 ** See also: [sqlite3_db_status()]
7299 int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
7300 int sqlite3_status64(
7301 int op,
7302 sqlite3_int64 *pCurrent,
7303 sqlite3_int64 *pHighwater,
7304 int resetFlag
7309 ** CAPI3REF: Status Parameters
7310 ** KEYWORDS: {status parameters}
7312 ** These integer constants designate various run-time status parameters
7313 ** that can be returned by [sqlite3_status()].
7315 ** <dl>
7316 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
7317 ** <dd>This parameter is the current amount of memory checked out
7318 ** using [sqlite3_malloc()], either directly or indirectly. The
7319 ** figure includes calls made to [sqlite3_malloc()] by the application
7320 ** and internal memory usage by the SQLite library. Auxiliary page-cache
7321 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
7322 ** this parameter. The amount returned is the sum of the allocation
7323 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
7325 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
7326 ** <dd>This parameter records the largest memory allocation request
7327 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
7328 ** internal equivalents). Only the value returned in the
7329 ** *pHighwater parameter to [sqlite3_status()] is of interest.
7330 ** The value written into the *pCurrent parameter is undefined.</dd>)^
7332 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
7333 ** <dd>This parameter records the number of separate memory allocations
7334 ** currently checked out.</dd>)^
7336 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
7337 ** <dd>This parameter returns the number of pages used out of the
7338 ** [pagecache memory allocator] that was configured using
7339 ** [SQLITE_CONFIG_PAGECACHE]. The
7340 ** value returned is in pages, not in bytes.</dd>)^
7342 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
7343 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
7344 ** <dd>This parameter returns the number of bytes of page cache
7345 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
7346 ** buffer and where forced to overflow to [sqlite3_malloc()]. The
7347 ** returned value includes allocations that overflowed because they
7348 ** where too large (they were larger than the "sz" parameter to
7349 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
7350 ** no space was left in the page cache.</dd>)^
7352 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
7353 ** <dd>This parameter records the largest memory allocation request
7354 ** handed to [pagecache memory allocator]. Only the value returned in the
7355 ** *pHighwater parameter to [sqlite3_status()] is of interest.
7356 ** The value written into the *pCurrent parameter is undefined.</dd>)^
7358 ** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
7359 ** <dd>No longer used.</dd>
7361 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
7362 ** <dd>No longer used.</dd>
7364 ** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
7365 ** <dd>No longer used.</dd>
7367 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
7368 ** <dd>The *pHighwater parameter records the deepest parser stack.
7369 ** The *pCurrent value is undefined. The *pHighwater value is only
7370 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
7371 ** </dl>
7373 ** New status parameters may be added from time to time.
7375 #define SQLITE_STATUS_MEMORY_USED 0
7376 #define SQLITE_STATUS_PAGECACHE_USED 1
7377 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
7378 #define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */
7379 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */
7380 #define SQLITE_STATUS_MALLOC_SIZE 5
7381 #define SQLITE_STATUS_PARSER_STACK 6
7382 #define SQLITE_STATUS_PAGECACHE_SIZE 7
7383 #define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */
7384 #define SQLITE_STATUS_MALLOC_COUNT 9
7387 ** CAPI3REF: Database Connection Status
7388 ** METHOD: sqlite3
7390 ** ^This interface is used to retrieve runtime status information
7391 ** about a single [database connection]. ^The first argument is the
7392 ** database connection object to be interrogated. ^The second argument
7393 ** is an integer constant, taken from the set of
7394 ** [SQLITE_DBSTATUS options], that
7395 ** determines the parameter to interrogate. The set of
7396 ** [SQLITE_DBSTATUS options] is likely
7397 ** to grow in future releases of SQLite.
7399 ** ^The current value of the requested parameter is written into *pCur
7400 ** and the highest instantaneous value is written into *pHiwtr. ^If
7401 ** the resetFlg is true, then the highest instantaneous value is
7402 ** reset back down to the current value.
7404 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
7405 ** non-zero [error code] on failure.
7407 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
7409 int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
7412 ** CAPI3REF: Status Parameters for database connections
7413 ** KEYWORDS: {SQLITE_DBSTATUS options}
7415 ** These constants are the available integer "verbs" that can be passed as
7416 ** the second argument to the [sqlite3_db_status()] interface.
7418 ** New verbs may be added in future releases of SQLite. Existing verbs
7419 ** might be discontinued. Applications should check the return code from
7420 ** [sqlite3_db_status()] to make sure that the call worked.
7421 ** The [sqlite3_db_status()] interface will return a non-zero error code
7422 ** if a discontinued or unsupported verb is invoked.
7424 ** <dl>
7425 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
7426 ** <dd>This parameter returns the number of lookaside memory slots currently
7427 ** checked out.</dd>)^
7429 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
7430 ** <dd>This parameter returns the number malloc attempts that were
7431 ** satisfied using lookaside memory. Only the high-water value is meaningful;
7432 ** the current value is always zero.)^
7434 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
7435 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
7436 ** <dd>This parameter returns the number malloc attempts that might have
7437 ** been satisfied using lookaside memory but failed due to the amount of
7438 ** memory requested being larger than the lookaside slot size.
7439 ** Only the high-water value is meaningful;
7440 ** the current value is always zero.)^
7442 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
7443 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
7444 ** <dd>This parameter returns the number malloc attempts that might have
7445 ** been satisfied using lookaside memory but failed due to all lookaside
7446 ** memory already being in use.
7447 ** Only the high-water value is meaningful;
7448 ** the current value is always zero.)^
7450 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
7451 ** <dd>This parameter returns the approximate number of bytes of heap
7452 ** memory used by all pager caches associated with the database connection.)^
7453 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
7455 ** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
7456 ** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
7457 ** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
7458 ** pager cache is shared between two or more connections the bytes of heap
7459 ** memory used by that pager cache is divided evenly between the attached
7460 ** connections.)^ In other words, if none of the pager caches associated
7461 ** with the database connection are shared, this request returns the same
7462 ** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
7463 ** shared, the value returned by this call will be smaller than that returned
7464 ** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
7465 ** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
7467 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
7468 ** <dd>This parameter returns the approximate number of bytes of heap
7469 ** memory used to store the schema for all databases associated
7470 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
7471 ** ^The full amount of memory used by the schemas is reported, even if the
7472 ** schema memory is shared with other database connections due to
7473 ** [shared cache mode] being enabled.
7474 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
7476 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
7477 ** <dd>This parameter returns the approximate number of bytes of heap
7478 ** and lookaside memory used by all prepared statements associated with
7479 ** the database connection.)^
7480 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
7481 ** </dd>
7483 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
7484 ** <dd>This parameter returns the number of pager cache hits that have
7485 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
7486 ** is always 0.
7487 ** </dd>
7489 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
7490 ** <dd>This parameter returns the number of pager cache misses that have
7491 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
7492 ** is always 0.
7493 ** </dd>
7495 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
7496 ** <dd>This parameter returns the number of dirty cache entries that have
7497 ** been written to disk. Specifically, the number of pages written to the
7498 ** wal file in wal mode databases, or the number of pages written to the
7499 ** database file in rollback mode databases. Any pages written as part of
7500 ** transaction rollback or database recovery operations are not included.
7501 ** If an IO or other error occurs while writing a page to disk, the effect
7502 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
7503 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
7504 ** </dd>
7506 ** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
7507 ** <dd>This parameter returns the number of dirty cache entries that have
7508 ** been written to disk in the middle of a transaction due to the page
7509 ** cache overflowing. Transactions are more efficient if they are written
7510 ** to disk all at once. When pages spill mid-transaction, that introduces
7511 ** additional overhead. This parameter can be used help identify
7512 ** inefficiencies that can be resolve by increasing the cache size.
7513 ** </dd>
7515 ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
7516 ** <dd>This parameter returns zero for the current value if and only if
7517 ** all foreign key constraints (deferred or immediate) have been
7518 ** resolved.)^ ^The highwater mark is always 0.
7519 ** </dd>
7520 ** </dl>
7522 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
7523 #define SQLITE_DBSTATUS_CACHE_USED 1
7524 #define SQLITE_DBSTATUS_SCHEMA_USED 2
7525 #define SQLITE_DBSTATUS_STMT_USED 3
7526 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
7527 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
7528 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
7529 #define SQLITE_DBSTATUS_CACHE_HIT 7
7530 #define SQLITE_DBSTATUS_CACHE_MISS 8
7531 #define SQLITE_DBSTATUS_CACHE_WRITE 9
7532 #define SQLITE_DBSTATUS_DEFERRED_FKS 10
7533 #define SQLITE_DBSTATUS_CACHE_USED_SHARED 11
7534 #define SQLITE_DBSTATUS_CACHE_SPILL 12
7535 #define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */
7539 ** CAPI3REF: Prepared Statement Status
7540 ** METHOD: sqlite3_stmt
7542 ** ^(Each prepared statement maintains various
7543 ** [SQLITE_STMTSTATUS counters] that measure the number
7544 ** of times it has performed specific operations.)^ These counters can
7545 ** be used to monitor the performance characteristics of the prepared
7546 ** statements. For example, if the number of table steps greatly exceeds
7547 ** the number of table searches or result rows, that would tend to indicate
7548 ** that the prepared statement is using a full table scan rather than
7549 ** an index.
7551 ** ^(This interface is used to retrieve and reset counter values from
7552 ** a [prepared statement]. The first argument is the prepared statement
7553 ** object to be interrogated. The second argument
7554 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
7555 ** to be interrogated.)^
7556 ** ^The current value of the requested counter is returned.
7557 ** ^If the resetFlg is true, then the counter is reset to zero after this
7558 ** interface call returns.
7560 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
7562 int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
7565 ** CAPI3REF: Status Parameters for prepared statements
7566 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
7568 ** These preprocessor macros define integer codes that name counter
7569 ** values associated with the [sqlite3_stmt_status()] interface.
7570 ** The meanings of the various counters are as follows:
7572 ** <dl>
7573 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
7574 ** <dd>^This is the number of times that SQLite has stepped forward in
7575 ** a table as part of a full table scan. Large numbers for this counter
7576 ** may indicate opportunities for performance improvement through
7577 ** careful use of indices.</dd>
7579 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
7580 ** <dd>^This is the number of sort operations that have occurred.
7581 ** A non-zero value in this counter may indicate an opportunity to
7582 ** improvement performance through careful use of indices.</dd>
7584 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
7585 ** <dd>^This is the number of rows inserted into transient indices that
7586 ** were created automatically in order to help joins run faster.
7587 ** A non-zero value in this counter may indicate an opportunity to
7588 ** improvement performance by adding permanent indices that do not
7589 ** need to be reinitialized each time the statement is run.</dd>
7591 ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
7592 ** <dd>^This is the number of virtual machine operations executed
7593 ** by the prepared statement if that number is less than or equal
7594 ** to 2147483647. The number of virtual machine operations can be
7595 ** used as a proxy for the total work done by the prepared statement.
7596 ** If the number of virtual machine operations exceeds 2147483647
7597 ** then the value returned by this statement status code is undefined.
7599 ** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
7600 ** <dd>^This is the number of times that the prepare statement has been
7601 ** automatically regenerated due to schema changes or change to
7602 ** [bound parameters] that might affect the query plan.
7604 ** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
7605 ** <dd>^This is the number of times that the prepared statement has
7606 ** been run. A single "run" for the purposes of this counter is one
7607 ** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
7608 ** The counter is incremented on the first [sqlite3_step()] call of each
7609 ** cycle.
7611 ** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
7612 ** <dd>^This is the approximate number of bytes of heap memory
7613 ** used to store the prepared statement. ^This value is not actually
7614 ** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
7615 ** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
7616 ** </dd>
7617 ** </dl>
7619 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
7620 #define SQLITE_STMTSTATUS_SORT 2
7621 #define SQLITE_STMTSTATUS_AUTOINDEX 3
7622 #define SQLITE_STMTSTATUS_VM_STEP 4
7623 #define SQLITE_STMTSTATUS_REPREPARE 5
7624 #define SQLITE_STMTSTATUS_RUN 6
7625 #define SQLITE_STMTSTATUS_MEMUSED 99
7628 ** CAPI3REF: Custom Page Cache Object
7630 ** The sqlite3_pcache type is opaque. It is implemented by
7631 ** the pluggable module. The SQLite core has no knowledge of
7632 ** its size or internal structure and never deals with the
7633 ** sqlite3_pcache object except by holding and passing pointers
7634 ** to the object.
7636 ** See [sqlite3_pcache_methods2] for additional information.
7638 typedef struct sqlite3_pcache sqlite3_pcache;
7641 ** CAPI3REF: Custom Page Cache Object
7643 ** The sqlite3_pcache_page object represents a single page in the
7644 ** page cache. The page cache will allocate instances of this
7645 ** object. Various methods of the page cache use pointers to instances
7646 ** of this object as parameters or as their return value.
7648 ** See [sqlite3_pcache_methods2] for additional information.
7650 typedef struct sqlite3_pcache_page sqlite3_pcache_page;
7651 struct sqlite3_pcache_page {
7652 void *pBuf; /* The content of the page */
7653 void *pExtra; /* Extra information associated with the page */
7657 ** CAPI3REF: Application Defined Page Cache.
7658 ** KEYWORDS: {page cache}
7660 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
7661 ** register an alternative page cache implementation by passing in an
7662 ** instance of the sqlite3_pcache_methods2 structure.)^
7663 ** In many applications, most of the heap memory allocated by
7664 ** SQLite is used for the page cache.
7665 ** By implementing a
7666 ** custom page cache using this API, an application can better control
7667 ** the amount of memory consumed by SQLite, the way in which
7668 ** that memory is allocated and released, and the policies used to
7669 ** determine exactly which parts of a database file are cached and for
7670 ** how long.
7672 ** The alternative page cache mechanism is an
7673 ** extreme measure that is only needed by the most demanding applications.
7674 ** The built-in page cache is recommended for most uses.
7676 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
7677 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
7678 ** the application may discard the parameter after the call to
7679 ** [sqlite3_config()] returns.)^
7681 ** [[the xInit() page cache method]]
7682 ** ^(The xInit() method is called once for each effective
7683 ** call to [sqlite3_initialize()])^
7684 ** (usually only once during the lifetime of the process). ^(The xInit()
7685 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
7686 ** The intent of the xInit() method is to set up global data structures
7687 ** required by the custom page cache implementation.
7688 ** ^(If the xInit() method is NULL, then the
7689 ** built-in default page cache is used instead of the application defined
7690 ** page cache.)^
7692 ** [[the xShutdown() page cache method]]
7693 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
7694 ** It can be used to clean up
7695 ** any outstanding resources before process shutdown, if required.
7696 ** ^The xShutdown() method may be NULL.
7698 ** ^SQLite automatically serializes calls to the xInit method,
7699 ** so the xInit method need not be threadsafe. ^The
7700 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
7701 ** not need to be threadsafe either. All other methods must be threadsafe
7702 ** in multithreaded applications.
7704 ** ^SQLite will never invoke xInit() more than once without an intervening
7705 ** call to xShutdown().
7707 ** [[the xCreate() page cache methods]]
7708 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
7709 ** SQLite will typically create one cache instance for each open database file,
7710 ** though this is not guaranteed. ^The
7711 ** first parameter, szPage, is the size in bytes of the pages that must
7712 ** be allocated by the cache. ^szPage will always a power of two. ^The
7713 ** second parameter szExtra is a number of bytes of extra storage
7714 ** associated with each page cache entry. ^The szExtra parameter will
7715 ** a number less than 250. SQLite will use the
7716 ** extra szExtra bytes on each page to store metadata about the underlying
7717 ** database page on disk. The value passed into szExtra depends
7718 ** on the SQLite version, the target platform, and how SQLite was compiled.
7719 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
7720 ** created will be used to cache database pages of a file stored on disk, or
7721 ** false if it is used for an in-memory database. The cache implementation
7722 ** does not have to do anything special based with the value of bPurgeable;
7723 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
7724 ** never invoke xUnpin() except to deliberately delete a page.
7725 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
7726 ** false will always have the "discard" flag set to true.
7727 ** ^Hence, a cache created with bPurgeable false will
7728 ** never contain any unpinned pages.
7730 ** [[the xCachesize() page cache method]]
7731 ** ^(The xCachesize() method may be called at any time by SQLite to set the
7732 ** suggested maximum cache-size (number of pages stored by) the cache
7733 ** instance passed as the first argument. This is the value configured using
7734 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
7735 ** parameter, the implementation is not required to do anything with this
7736 ** value; it is advisory only.
7738 ** [[the xPagecount() page cache methods]]
7739 ** The xPagecount() method must return the number of pages currently
7740 ** stored in the cache, both pinned and unpinned.
7742 ** [[the xFetch() page cache methods]]
7743 ** The xFetch() method locates a page in the cache and returns a pointer to
7744 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
7745 ** The pBuf element of the returned sqlite3_pcache_page object will be a
7746 ** pointer to a buffer of szPage bytes used to store the content of a
7747 ** single database page. The pExtra element of sqlite3_pcache_page will be
7748 ** a pointer to the szExtra bytes of extra storage that SQLite has requested
7749 ** for each entry in the page cache.
7751 ** The page to be fetched is determined by the key. ^The minimum key value
7752 ** is 1. After it has been retrieved using xFetch, the page is considered
7753 ** to be "pinned".
7755 ** If the requested page is already in the page cache, then the page cache
7756 ** implementation must return a pointer to the page buffer with its content
7757 ** intact. If the requested page is not already in the cache, then the
7758 ** cache implementation should use the value of the createFlag
7759 ** parameter to help it determined what action to take:
7761 ** <table border=1 width=85% align=center>
7762 ** <tr><th> createFlag <th> Behavior when page is not already in cache
7763 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
7764 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
7765 ** Otherwise return NULL.
7766 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
7767 ** NULL if allocating a new page is effectively impossible.
7768 ** </table>
7770 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
7771 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
7772 ** failed.)^ In between the to xFetch() calls, SQLite may
7773 ** attempt to unpin one or more cache pages by spilling the content of
7774 ** pinned pages to disk and synching the operating system disk cache.
7776 ** [[the xUnpin() page cache method]]
7777 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
7778 ** as its second argument. If the third parameter, discard, is non-zero,
7779 ** then the page must be evicted from the cache.
7780 ** ^If the discard parameter is
7781 ** zero, then the page may be discarded or retained at the discretion of
7782 ** page cache implementation. ^The page cache implementation
7783 ** may choose to evict unpinned pages at any time.
7785 ** The cache must not perform any reference counting. A single
7786 ** call to xUnpin() unpins the page regardless of the number of prior calls
7787 ** to xFetch().
7789 ** [[the xRekey() page cache methods]]
7790 ** The xRekey() method is used to change the key value associated with the
7791 ** page passed as the second argument. If the cache
7792 ** previously contains an entry associated with newKey, it must be
7793 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
7794 ** to be pinned.
7796 ** When SQLite calls the xTruncate() method, the cache must discard all
7797 ** existing cache entries with page numbers (keys) greater than or equal
7798 ** to the value of the iLimit parameter passed to xTruncate(). If any
7799 ** of these pages are pinned, they are implicitly unpinned, meaning that
7800 ** they can be safely discarded.
7802 ** [[the xDestroy() page cache method]]
7803 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
7804 ** All resources associated with the specified cache should be freed. ^After
7805 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
7806 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
7807 ** functions.
7809 ** [[the xShrink() page cache method]]
7810 ** ^SQLite invokes the xShrink() method when it wants the page cache to
7811 ** free up as much of heap memory as possible. The page cache implementation
7812 ** is not obligated to free any memory, but well-behaved implementations should
7813 ** do their best.
7815 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
7816 struct sqlite3_pcache_methods2 {
7817 int iVersion;
7818 void *pArg;
7819 int (*xInit)(void*);
7820 void (*xShutdown)(void*);
7821 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
7822 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
7823 int (*xPagecount)(sqlite3_pcache*);
7824 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
7825 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
7826 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
7827 unsigned oldKey, unsigned newKey);
7828 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
7829 void (*xDestroy)(sqlite3_pcache*);
7830 void (*xShrink)(sqlite3_pcache*);
7834 ** This is the obsolete pcache_methods object that has now been replaced
7835 ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
7836 ** retained in the header file for backwards compatibility only.
7838 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
7839 struct sqlite3_pcache_methods {
7840 void *pArg;
7841 int (*xInit)(void*);
7842 void (*xShutdown)(void*);
7843 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
7844 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
7845 int (*xPagecount)(sqlite3_pcache*);
7846 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
7847 void (*xUnpin)(sqlite3_pcache*, void*, int discard);
7848 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
7849 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
7850 void (*xDestroy)(sqlite3_pcache*);
7855 ** CAPI3REF: Online Backup Object
7857 ** The sqlite3_backup object records state information about an ongoing
7858 ** online backup operation. ^The sqlite3_backup object is created by
7859 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
7860 ** [sqlite3_backup_finish()].
7862 ** See Also: [Using the SQLite Online Backup API]
7864 typedef struct sqlite3_backup sqlite3_backup;
7867 ** CAPI3REF: Online Backup API.
7869 ** The backup API copies the content of one database into another.
7870 ** It is useful either for creating backups of databases or
7871 ** for copying in-memory databases to or from persistent files.
7873 ** See Also: [Using the SQLite Online Backup API]
7875 ** ^SQLite holds a write transaction open on the destination database file
7876 ** for the duration of the backup operation.
7877 ** ^The source database is read-locked only while it is being read;
7878 ** it is not locked continuously for the entire backup operation.
7879 ** ^Thus, the backup may be performed on a live source database without
7880 ** preventing other database connections from
7881 ** reading or writing to the source database while the backup is underway.
7883 ** ^(To perform a backup operation:
7884 ** <ol>
7885 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
7886 ** backup,
7887 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
7888 ** the data between the two databases, and finally
7889 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
7890 ** associated with the backup operation.
7891 ** </ol>)^
7892 ** There should be exactly one call to sqlite3_backup_finish() for each
7893 ** successful call to sqlite3_backup_init().
7895 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
7897 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
7898 ** [database connection] associated with the destination database
7899 ** and the database name, respectively.
7900 ** ^The database name is "main" for the main database, "temp" for the
7901 ** temporary database, or the name specified after the AS keyword in
7902 ** an [ATTACH] statement for an attached database.
7903 ** ^The S and M arguments passed to
7904 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
7905 ** and database name of the source database, respectively.
7906 ** ^The source and destination [database connections] (parameters S and D)
7907 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
7908 ** an error.
7910 ** ^A call to sqlite3_backup_init() will fail, returning NULL, if
7911 ** there is already a read or read-write transaction open on the
7912 ** destination database.
7914 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
7915 ** returned and an error code and error message are stored in the
7916 ** destination [database connection] D.
7917 ** ^The error code and message for the failed call to sqlite3_backup_init()
7918 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
7919 ** [sqlite3_errmsg16()] functions.
7920 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
7921 ** [sqlite3_backup] object.
7922 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
7923 ** sqlite3_backup_finish() functions to perform the specified backup
7924 ** operation.
7926 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
7928 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
7929 ** the source and destination databases specified by [sqlite3_backup] object B.
7930 ** ^If N is negative, all remaining source pages are copied.
7931 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
7932 ** are still more pages to be copied, then the function returns [SQLITE_OK].
7933 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
7934 ** from source to destination, then it returns [SQLITE_DONE].
7935 ** ^If an error occurs while running sqlite3_backup_step(B,N),
7936 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
7937 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
7938 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
7939 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
7941 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
7942 ** <ol>
7943 ** <li> the destination database was opened read-only, or
7944 ** <li> the destination database is using write-ahead-log journaling
7945 ** and the destination and source page sizes differ, or
7946 ** <li> the destination database is an in-memory database and the
7947 ** destination and source page sizes differ.
7948 ** </ol>)^
7950 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
7951 ** the [sqlite3_busy_handler | busy-handler function]
7952 ** is invoked (if one is specified). ^If the
7953 ** busy-handler returns non-zero before the lock is available, then
7954 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
7955 ** sqlite3_backup_step() can be retried later. ^If the source
7956 ** [database connection]
7957 ** is being used to write to the source database when sqlite3_backup_step()
7958 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
7959 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
7960 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
7961 ** [SQLITE_READONLY] is returned, then
7962 ** there is no point in retrying the call to sqlite3_backup_step(). These
7963 ** errors are considered fatal.)^ The application must accept
7964 ** that the backup operation has failed and pass the backup operation handle
7965 ** to the sqlite3_backup_finish() to release associated resources.
7967 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
7968 ** on the destination file. ^The exclusive lock is not released until either
7969 ** sqlite3_backup_finish() is called or the backup operation is complete
7970 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
7971 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
7972 ** lasts for the duration of the sqlite3_backup_step() call.
7973 ** ^Because the source database is not locked between calls to
7974 ** sqlite3_backup_step(), the source database may be modified mid-way
7975 ** through the backup process. ^If the source database is modified by an
7976 ** external process or via a database connection other than the one being
7977 ** used by the backup operation, then the backup will be automatically
7978 ** restarted by the next call to sqlite3_backup_step(). ^If the source
7979 ** database is modified by the using the same database connection as is used
7980 ** by the backup operation, then the backup database is automatically
7981 ** updated at the same time.
7983 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
7985 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
7986 ** application wishes to abandon the backup operation, the application
7987 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
7988 ** ^The sqlite3_backup_finish() interfaces releases all
7989 ** resources associated with the [sqlite3_backup] object.
7990 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
7991 ** active write-transaction on the destination database is rolled back.
7992 ** The [sqlite3_backup] object is invalid
7993 ** and may not be used following a call to sqlite3_backup_finish().
7995 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
7996 ** sqlite3_backup_step() errors occurred, regardless or whether or not
7997 ** sqlite3_backup_step() completed.
7998 ** ^If an out-of-memory condition or IO error occurred during any prior
7999 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
8000 ** sqlite3_backup_finish() returns the corresponding [error code].
8002 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
8003 ** is not a permanent error and does not affect the return value of
8004 ** sqlite3_backup_finish().
8006 ** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
8007 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
8009 ** ^The sqlite3_backup_remaining() routine returns the number of pages still
8010 ** to be backed up at the conclusion of the most recent sqlite3_backup_step().
8011 ** ^The sqlite3_backup_pagecount() routine returns the total number of pages
8012 ** in the source database at the conclusion of the most recent
8013 ** sqlite3_backup_step().
8014 ** ^(The values returned by these functions are only updated by
8015 ** sqlite3_backup_step(). If the source database is modified in a way that
8016 ** changes the size of the source database or the number of pages remaining,
8017 ** those changes are not reflected in the output of sqlite3_backup_pagecount()
8018 ** and sqlite3_backup_remaining() until after the next
8019 ** sqlite3_backup_step().)^
8021 ** <b>Concurrent Usage of Database Handles</b>
8023 ** ^The source [database connection] may be used by the application for other
8024 ** purposes while a backup operation is underway or being initialized.
8025 ** ^If SQLite is compiled and configured to support threadsafe database
8026 ** connections, then the source database connection may be used concurrently
8027 ** from within other threads.
8029 ** However, the application must guarantee that the destination
8030 ** [database connection] is not passed to any other API (by any thread) after
8031 ** sqlite3_backup_init() is called and before the corresponding call to
8032 ** sqlite3_backup_finish(). SQLite does not currently check to see
8033 ** if the application incorrectly accesses the destination [database connection]
8034 ** and so no error code is reported, but the operations may malfunction
8035 ** nevertheless. Use of the destination database connection while a
8036 ** backup is in progress might also also cause a mutex deadlock.
8038 ** If running in [shared cache mode], the application must
8039 ** guarantee that the shared cache used by the destination database
8040 ** is not accessed while the backup is running. In practice this means
8041 ** that the application must guarantee that the disk file being
8042 ** backed up to is not accessed by any connection within the process,
8043 ** not just the specific connection that was passed to sqlite3_backup_init().
8045 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
8046 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
8047 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
8048 ** APIs are not strictly speaking threadsafe. If they are invoked at the
8049 ** same time as another thread is invoking sqlite3_backup_step() it is
8050 ** possible that they return invalid values.
8052 sqlite3_backup *sqlite3_backup_init(
8053 sqlite3 *pDest, /* Destination database handle */
8054 const char *zDestName, /* Destination database name */
8055 sqlite3 *pSource, /* Source database handle */
8056 const char *zSourceName /* Source database name */
8058 int sqlite3_backup_step(sqlite3_backup *p, int nPage);
8059 int sqlite3_backup_finish(sqlite3_backup *p);
8060 int sqlite3_backup_remaining(sqlite3_backup *p);
8061 int sqlite3_backup_pagecount(sqlite3_backup *p);
8064 ** CAPI3REF: Unlock Notification
8065 ** METHOD: sqlite3
8067 ** ^When running in shared-cache mode, a database operation may fail with
8068 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
8069 ** individual tables within the shared-cache cannot be obtained. See
8070 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
8071 ** ^This API may be used to register a callback that SQLite will invoke
8072 ** when the connection currently holding the required lock relinquishes it.
8073 ** ^This API is only available if the library was compiled with the
8074 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
8076 ** See Also: [Using the SQLite Unlock Notification Feature].
8078 ** ^Shared-cache locks are released when a database connection concludes
8079 ** its current transaction, either by committing it or rolling it back.
8081 ** ^When a connection (known as the blocked connection) fails to obtain a
8082 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
8083 ** identity of the database connection (the blocking connection) that
8084 ** has locked the required resource is stored internally. ^After an
8085 ** application receives an SQLITE_LOCKED error, it may call the
8086 ** sqlite3_unlock_notify() method with the blocked connection handle as
8087 ** the first argument to register for a callback that will be invoked
8088 ** when the blocking connections current transaction is concluded. ^The
8089 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
8090 ** call that concludes the blocking connections transaction.
8092 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
8093 ** there is a chance that the blocking connection will have already
8094 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
8095 ** If this happens, then the specified callback is invoked immediately,
8096 ** from within the call to sqlite3_unlock_notify().)^
8098 ** ^If the blocked connection is attempting to obtain a write-lock on a
8099 ** shared-cache table, and more than one other connection currently holds
8100 ** a read-lock on the same table, then SQLite arbitrarily selects one of
8101 ** the other connections to use as the blocking connection.
8103 ** ^(There may be at most one unlock-notify callback registered by a
8104 ** blocked connection. If sqlite3_unlock_notify() is called when the
8105 ** blocked connection already has a registered unlock-notify callback,
8106 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
8107 ** called with a NULL pointer as its second argument, then any existing
8108 ** unlock-notify callback is canceled. ^The blocked connections
8109 ** unlock-notify callback may also be canceled by closing the blocked
8110 ** connection using [sqlite3_close()].
8112 ** The unlock-notify callback is not reentrant. If an application invokes
8113 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
8114 ** crash or deadlock may be the result.
8116 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
8117 ** returns SQLITE_OK.
8119 ** <b>Callback Invocation Details</b>
8121 ** When an unlock-notify callback is registered, the application provides a
8122 ** single void* pointer that is passed to the callback when it is invoked.
8123 ** However, the signature of the callback function allows SQLite to pass
8124 ** it an array of void* context pointers. The first argument passed to
8125 ** an unlock-notify callback is a pointer to an array of void* pointers,
8126 ** and the second is the number of entries in the array.
8128 ** When a blocking connections transaction is concluded, there may be
8129 ** more than one blocked connection that has registered for an unlock-notify
8130 ** callback. ^If two or more such blocked connections have specified the
8131 ** same callback function, then instead of invoking the callback function
8132 ** multiple times, it is invoked once with the set of void* context pointers
8133 ** specified by the blocked connections bundled together into an array.
8134 ** This gives the application an opportunity to prioritize any actions
8135 ** related to the set of unblocked database connections.
8137 ** <b>Deadlock Detection</b>
8139 ** Assuming that after registering for an unlock-notify callback a
8140 ** database waits for the callback to be issued before taking any further
8141 ** action (a reasonable assumption), then using this API may cause the
8142 ** application to deadlock. For example, if connection X is waiting for
8143 ** connection Y's transaction to be concluded, and similarly connection
8144 ** Y is waiting on connection X's transaction, then neither connection
8145 ** will proceed and the system may remain deadlocked indefinitely.
8147 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
8148 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
8149 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
8150 ** unlock-notify callback is registered. The system is said to be in
8151 ** a deadlocked state if connection A has registered for an unlock-notify
8152 ** callback on the conclusion of connection B's transaction, and connection
8153 ** B has itself registered for an unlock-notify callback when connection
8154 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
8155 ** the system is also considered to be deadlocked if connection B has
8156 ** registered for an unlock-notify callback on the conclusion of connection
8157 ** C's transaction, where connection C is waiting on connection A. ^Any
8158 ** number of levels of indirection are allowed.
8160 ** <b>The "DROP TABLE" Exception</b>
8162 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
8163 ** always appropriate to call sqlite3_unlock_notify(). There is however,
8164 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
8165 ** SQLite checks if there are any currently executing SELECT statements
8166 ** that belong to the same connection. If there are, SQLITE_LOCKED is
8167 ** returned. In this case there is no "blocking connection", so invoking
8168 ** sqlite3_unlock_notify() results in the unlock-notify callback being
8169 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
8170 ** or "DROP INDEX" query, an infinite loop might be the result.
8172 ** One way around this problem is to check the extended error code returned
8173 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
8174 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
8175 ** the special "DROP TABLE/INDEX" case, the extended error code is just
8176 ** SQLITE_LOCKED.)^
8178 int sqlite3_unlock_notify(
8179 sqlite3 *pBlocked, /* Waiting connection */
8180 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
8181 void *pNotifyArg /* Argument to pass to xNotify */
8186 ** CAPI3REF: String Comparison
8188 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
8189 ** and extensions to compare the contents of two buffers containing UTF-8
8190 ** strings in a case-independent fashion, using the same definition of "case
8191 ** independence" that SQLite uses internally when comparing identifiers.
8193 int sqlite3_stricmp(const char *, const char *);
8194 int sqlite3_strnicmp(const char *, const char *, int);
8197 ** CAPI3REF: String Globbing
8199 ** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
8200 ** string X matches the [GLOB] pattern P.
8201 ** ^The definition of [GLOB] pattern matching used in
8202 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
8203 ** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function
8204 ** is case sensitive.
8206 ** Note that this routine returns zero on a match and non-zero if the strings
8207 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
8209 ** See also: [sqlite3_strlike()].
8211 int sqlite3_strglob(const char *zGlob, const char *zStr);
8214 ** CAPI3REF: String LIKE Matching
8216 ** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
8217 ** string X matches the [LIKE] pattern P with escape character E.
8218 ** ^The definition of [LIKE] pattern matching used in
8219 ** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
8220 ** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without
8221 ** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
8222 ** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
8223 ** insensitive - equivalent upper and lower case ASCII characters match
8224 ** one another.
8226 ** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
8227 ** only ASCII characters are case folded.
8229 ** Note that this routine returns zero on a match and non-zero if the strings
8230 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
8232 ** See also: [sqlite3_strglob()].
8234 int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
8237 ** CAPI3REF: Error Logging Interface
8239 ** ^The [sqlite3_log()] interface writes a message into the [error log]
8240 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
8241 ** ^If logging is enabled, the zFormat string and subsequent arguments are
8242 ** used with [sqlite3_snprintf()] to generate the final output string.
8244 ** The sqlite3_log() interface is intended for use by extensions such as
8245 ** virtual tables, collating functions, and SQL functions. While there is
8246 ** nothing to prevent an application from calling sqlite3_log(), doing so
8247 ** is considered bad form.
8249 ** The zFormat string must not be NULL.
8251 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
8252 ** will not use dynamically allocated memory. The log message is stored in
8253 ** a fixed-length buffer on the stack. If the log message is longer than
8254 ** a few hundred characters, it will be truncated to the length of the
8255 ** buffer.
8257 void sqlite3_log(int iErrCode, const char *zFormat, ...);
8260 ** CAPI3REF: Write-Ahead Log Commit Hook
8261 ** METHOD: sqlite3
8263 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
8264 ** is invoked each time data is committed to a database in wal mode.
8266 ** ^(The callback is invoked by SQLite after the commit has taken place and
8267 ** the associated write-lock on the database released)^, so the implementation
8268 ** may read, write or [checkpoint] the database as required.
8270 ** ^The first parameter passed to the callback function when it is invoked
8271 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
8272 ** registering the callback. ^The second is a copy of the database handle.
8273 ** ^The third parameter is the name of the database that was written to -
8274 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
8275 ** is the number of pages currently in the write-ahead log file,
8276 ** including those that were just committed.
8278 ** The callback function should normally return [SQLITE_OK]. ^If an error
8279 ** code is returned, that error will propagate back up through the
8280 ** SQLite code base to cause the statement that provoked the callback
8281 ** to report an error, though the commit will have still occurred. If the
8282 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
8283 ** that does not correspond to any valid SQLite error code, the results
8284 ** are undefined.
8286 ** A single database handle may have at most a single write-ahead log callback
8287 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
8288 ** previously registered write-ahead log callback. ^Note that the
8289 ** [sqlite3_wal_autocheckpoint()] interface and the
8290 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
8291 ** overwrite any prior [sqlite3_wal_hook()] settings.
8293 void *sqlite3_wal_hook(
8294 sqlite3*,
8295 int(*)(void *,sqlite3*,const char*,int),
8296 void*
8300 ** CAPI3REF: Configure an auto-checkpoint
8301 ** METHOD: sqlite3
8303 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
8304 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
8305 ** to automatically [checkpoint]
8306 ** after committing a transaction if there are N or
8307 ** more frames in the [write-ahead log] file. ^Passing zero or
8308 ** a negative value as the nFrame parameter disables automatic
8309 ** checkpoints entirely.
8311 ** ^The callback registered by this function replaces any existing callback
8312 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
8313 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
8314 ** configured by this function.
8316 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
8317 ** from SQL.
8319 ** ^Checkpoints initiated by this mechanism are
8320 ** [sqlite3_wal_checkpoint_v2|PASSIVE].
8322 ** ^Every new [database connection] defaults to having the auto-checkpoint
8323 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
8324 ** pages. The use of this interface
8325 ** is only necessary if the default setting is found to be suboptimal
8326 ** for a particular application.
8328 int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
8331 ** CAPI3REF: Checkpoint a database
8332 ** METHOD: sqlite3
8334 ** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
8335 ** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
8337 ** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
8338 ** [write-ahead log] for database X on [database connection] D to be
8339 ** transferred into the database file and for the write-ahead log to
8340 ** be reset. See the [checkpointing] documentation for addition
8341 ** information.
8343 ** This interface used to be the only way to cause a checkpoint to
8344 ** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
8345 ** interface was added. This interface is retained for backwards
8346 ** compatibility and as a convenience for applications that need to manually
8347 ** start a callback but which do not need the full power (and corresponding
8348 ** complication) of [sqlite3_wal_checkpoint_v2()].
8350 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
8353 ** CAPI3REF: Checkpoint a database
8354 ** METHOD: sqlite3
8356 ** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
8357 ** operation on database X of [database connection] D in mode M. Status
8358 ** information is written back into integers pointed to by L and C.)^
8359 ** ^(The M parameter must be a valid [checkpoint mode]:)^
8361 ** <dl>
8362 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
8363 ** ^Checkpoint as many frames as possible without waiting for any database
8364 ** readers or writers to finish, then sync the database file if all frames
8365 ** in the log were checkpointed. ^The [busy-handler callback]
8366 ** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
8367 ** ^On the other hand, passive mode might leave the checkpoint unfinished
8368 ** if there are concurrent readers or writers.
8370 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
8371 ** ^This mode blocks (it invokes the
8372 ** [sqlite3_busy_handler|busy-handler callback]) until there is no
8373 ** database writer and all readers are reading from the most recent database
8374 ** snapshot. ^It then checkpoints all frames in the log file and syncs the
8375 ** database file. ^This mode blocks new database writers while it is pending,
8376 ** but new database readers are allowed to continue unimpeded.
8378 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
8379 ** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
8380 ** that after checkpointing the log file it blocks (calls the
8381 ** [busy-handler callback])
8382 ** until all readers are reading from the database file only. ^This ensures
8383 ** that the next writer will restart the log file from the beginning.
8384 ** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
8385 ** database writer attempts while it is pending, but does not impede readers.
8387 ** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
8388 ** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
8389 ** addition that it also truncates the log file to zero bytes just prior
8390 ** to a successful return.
8391 ** </dl>
8393 ** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
8394 ** the log file or to -1 if the checkpoint could not run because
8395 ** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
8396 ** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
8397 ** log file (including any that were already checkpointed before the function
8398 ** was called) or to -1 if the checkpoint could not run due to an error or
8399 ** because the database is not in WAL mode. ^Note that upon successful
8400 ** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
8401 ** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
8403 ** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
8404 ** any other process is running a checkpoint operation at the same time, the
8405 ** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
8406 ** busy-handler configured, it will not be invoked in this case.
8408 ** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
8409 ** exclusive "writer" lock on the database file. ^If the writer lock cannot be
8410 ** obtained immediately, and a busy-handler is configured, it is invoked and
8411 ** the writer lock retried until either the busy-handler returns 0 or the lock
8412 ** is successfully obtained. ^The busy-handler is also invoked while waiting for
8413 ** database readers as described above. ^If the busy-handler returns 0 before
8414 ** the writer lock is obtained or while waiting for database readers, the
8415 ** checkpoint operation proceeds from that point in the same way as
8416 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
8417 ** without blocking any further. ^SQLITE_BUSY is returned in this case.
8419 ** ^If parameter zDb is NULL or points to a zero length string, then the
8420 ** specified operation is attempted on all WAL databases [attached] to
8421 ** [database connection] db. In this case the
8422 ** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
8423 ** an SQLITE_BUSY error is encountered when processing one or more of the
8424 ** attached WAL databases, the operation is still attempted on any remaining
8425 ** attached databases and SQLITE_BUSY is returned at the end. ^If any other
8426 ** error occurs while processing an attached database, processing is abandoned
8427 ** and the error code is returned to the caller immediately. ^If no error
8428 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
8429 ** databases, SQLITE_OK is returned.
8431 ** ^If database zDb is the name of an attached database that is not in WAL
8432 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
8433 ** zDb is not NULL (or a zero length string) and is not the name of any
8434 ** attached database, SQLITE_ERROR is returned to the caller.
8436 ** ^Unless it returns SQLITE_MISUSE,
8437 ** the sqlite3_wal_checkpoint_v2() interface
8438 ** sets the error information that is queried by
8439 ** [sqlite3_errcode()] and [sqlite3_errmsg()].
8441 ** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
8442 ** from SQL.
8444 int sqlite3_wal_checkpoint_v2(
8445 sqlite3 *db, /* Database handle */
8446 const char *zDb, /* Name of attached database (or NULL) */
8447 int eMode, /* SQLITE_CHECKPOINT_* value */
8448 int *pnLog, /* OUT: Size of WAL log in frames */
8449 int *pnCkpt /* OUT: Total number of frames checkpointed */
8453 ** CAPI3REF: Checkpoint Mode Values
8454 ** KEYWORDS: {checkpoint mode}
8456 ** These constants define all valid values for the "checkpoint mode" passed
8457 ** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
8458 ** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
8459 ** meaning of each of these checkpoint modes.
8461 #define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */
8462 #define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */
8463 #define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */
8464 #define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */
8467 ** CAPI3REF: Virtual Table Interface Configuration
8469 ** This function may be called by either the [xConnect] or [xCreate] method
8470 ** of a [virtual table] implementation to configure
8471 ** various facets of the virtual table interface.
8473 ** If this interface is invoked outside the context of an xConnect or
8474 ** xCreate virtual table method then the behavior is undefined.
8476 ** At present, there is only one option that may be configured using
8477 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options
8478 ** may be added in the future.
8480 int sqlite3_vtab_config(sqlite3*, int op, ...);
8483 ** CAPI3REF: Virtual Table Configuration Options
8485 ** These macros define the various options to the
8486 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
8487 ** can use to customize and optimize their behavior.
8489 ** <dl>
8490 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
8491 ** <dd>Calls of the form
8492 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
8493 ** where X is an integer. If X is zero, then the [virtual table] whose
8494 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
8495 ** support constraints. In this configuration (which is the default) if
8496 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
8497 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
8498 ** specified as part of the users SQL statement, regardless of the actual
8499 ** ON CONFLICT mode specified.
8501 ** If X is non-zero, then the virtual table implementation guarantees
8502 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
8503 ** any modifications to internal or persistent data structures have been made.
8504 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
8505 ** is able to roll back a statement or database transaction, and abandon
8506 ** or continue processing the current SQL statement as appropriate.
8507 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
8508 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
8509 ** had been ABORT.
8511 ** Virtual table implementations that are required to handle OR REPLACE
8512 ** must do so within the [xUpdate] method. If a call to the
8513 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
8514 ** CONFLICT policy is REPLACE, the virtual table implementation should
8515 ** silently replace the appropriate rows within the xUpdate callback and
8516 ** return SQLITE_OK. Or, if this is not possible, it may return
8517 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
8518 ** constraint handling.
8519 ** </dl>
8521 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
8524 ** CAPI3REF: Determine The Virtual Table Conflict Policy
8526 ** This function may only be called from within a call to the [xUpdate] method
8527 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
8528 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
8529 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
8530 ** of the SQL statement that triggered the call to the [xUpdate] method of the
8531 ** [virtual table].
8533 int sqlite3_vtab_on_conflict(sqlite3 *);
8536 ** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
8538 ** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
8539 ** method of a [virtual table], then it returns true if and only if the
8540 ** column is being fetched as part of an UPDATE operation during which the
8541 ** column value will not change. Applications might use this to substitute
8542 ** a return value that is less expensive to compute and that the corresponding
8543 ** [xUpdate] method understands as a "no-change" value.
8545 ** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
8546 ** the column is not changed by the UPDATE statement, then the xColumn
8547 ** method can optionally return without setting a result, without calling
8548 ** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
8549 ** In that case, [sqlite3_value_nochange(X)] will return true for the
8550 ** same column in the [xUpdate] method.
8552 int sqlite3_vtab_nochange(sqlite3_context*);
8555 ** CAPI3REF: Determine The Collation For a Virtual Table Constraint
8557 ** This function may only be called from within a call to the [xBestIndex]
8558 ** method of a [virtual table].
8560 ** The first argument must be the sqlite3_index_info object that is the
8561 ** first parameter to the xBestIndex() method. The second argument must be
8562 ** an index into the aConstraint[] array belonging to the sqlite3_index_info
8563 ** structure passed to xBestIndex. This function returns a pointer to a buffer
8564 ** containing the name of the collation sequence for the corresponding
8565 ** constraint.
8567 SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
8570 ** CAPI3REF: Conflict resolution modes
8571 ** KEYWORDS: {conflict resolution mode}
8573 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
8574 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
8575 ** is for the SQL statement being evaluated.
8577 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
8578 ** return value from the [sqlite3_set_authorizer()] callback and that
8579 ** [SQLITE_ABORT] is also a [result code].
8581 #define SQLITE_ROLLBACK 1
8582 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
8583 #define SQLITE_FAIL 3
8584 /* #define SQLITE_ABORT 4 // Also an error code */
8585 #define SQLITE_REPLACE 5
8588 ** CAPI3REF: Prepared Statement Scan Status Opcodes
8589 ** KEYWORDS: {scanstatus options}
8591 ** The following constants can be used for the T parameter to the
8592 ** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a
8593 ** different metric for sqlite3_stmt_scanstatus() to return.
8595 ** When the value returned to V is a string, space to hold that string is
8596 ** managed by the prepared statement S and will be automatically freed when
8597 ** S is finalized.
8599 ** <dl>
8600 ** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
8601 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be
8602 ** set to the total number of times that the X-th loop has run.</dd>
8604 ** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
8605 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set
8606 ** to the total number of rows examined by all iterations of the X-th loop.</dd>
8608 ** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
8609 ** <dd>^The "double" variable pointed to by the T parameter will be set to the
8610 ** query planner's estimate for the average number of rows output from each
8611 ** iteration of the X-th loop. If the query planner's estimates was accurate,
8612 ** then this value will approximate the quotient NVISIT/NLOOP and the
8613 ** product of this value for all prior loops with the same SELECTID will
8614 ** be the NLOOP value for the current loop.
8616 ** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
8617 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
8618 ** to a zero-terminated UTF-8 string containing the name of the index or table
8619 ** used for the X-th loop.
8621 ** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
8622 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
8623 ** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
8624 ** description for the X-th loop.
8626 ** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
8627 ** <dd>^The "int" variable pointed to by the T parameter will be set to the
8628 ** "select-id" for the X-th loop. The select-id identifies which query or
8629 ** subquery the loop is part of. The main query has a select-id of zero.
8630 ** The select-id is the same value as is output in the first column
8631 ** of an [EXPLAIN QUERY PLAN] query.
8632 ** </dl>
8634 #define SQLITE_SCANSTAT_NLOOP 0
8635 #define SQLITE_SCANSTAT_NVISIT 1
8636 #define SQLITE_SCANSTAT_EST 2
8637 #define SQLITE_SCANSTAT_NAME 3
8638 #define SQLITE_SCANSTAT_EXPLAIN 4
8639 #define SQLITE_SCANSTAT_SELECTID 5
8642 ** CAPI3REF: Prepared Statement Scan Status
8643 ** METHOD: sqlite3_stmt
8645 ** This interface returns information about the predicted and measured
8646 ** performance for pStmt. Advanced applications can use this
8647 ** interface to compare the predicted and the measured performance and
8648 ** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
8650 ** Since this interface is expected to be rarely used, it is only
8651 ** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
8652 ** compile-time option.
8654 ** The "iScanStatusOp" parameter determines which status information to return.
8655 ** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
8656 ** of this interface is undefined.
8657 ** ^The requested measurement is written into a variable pointed to by
8658 ** the "pOut" parameter.
8659 ** Parameter "idx" identifies the specific loop to retrieve statistics for.
8660 ** Loops are numbered starting from zero. ^If idx is out of range - less than
8661 ** zero or greater than or equal to the total number of loops used to implement
8662 ** the statement - a non-zero value is returned and the variable that pOut
8663 ** points to is unchanged.
8665 ** ^Statistics might not be available for all loops in all statements. ^In cases
8666 ** where there exist loops with no available statistics, this function behaves
8667 ** as if the loop did not exist - it returns non-zero and leave the variable
8668 ** that pOut points to unchanged.
8670 ** See also: [sqlite3_stmt_scanstatus_reset()]
8672 int sqlite3_stmt_scanstatus(
8673 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */
8674 int idx, /* Index of loop to report on */
8675 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */
8676 void *pOut /* Result written here */
8680 ** CAPI3REF: Zero Scan-Status Counters
8681 ** METHOD: sqlite3_stmt
8683 ** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
8685 ** This API is only available if the library is built with pre-processor
8686 ** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
8688 void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
8691 ** CAPI3REF: Flush caches to disk mid-transaction
8693 ** ^If a write-transaction is open on [database connection] D when the
8694 ** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
8695 ** pages in the pager-cache that are not currently in use are written out
8696 ** to disk. A dirty page may be in use if a database cursor created by an
8697 ** active SQL statement is reading from it, or if it is page 1 of a database
8698 ** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)]
8699 ** interface flushes caches for all schemas - "main", "temp", and
8700 ** any [attached] databases.
8702 ** ^If this function needs to obtain extra database locks before dirty pages
8703 ** can be flushed to disk, it does so. ^If those locks cannot be obtained
8704 ** immediately and there is a busy-handler callback configured, it is invoked
8705 ** in the usual manner. ^If the required lock still cannot be obtained, then
8706 ** the database is skipped and an attempt made to flush any dirty pages
8707 ** belonging to the next (if any) database. ^If any databases are skipped
8708 ** because locks cannot be obtained, but no other error occurs, this
8709 ** function returns SQLITE_BUSY.
8711 ** ^If any other error occurs while flushing dirty pages to disk (for
8712 ** example an IO error or out-of-memory condition), then processing is
8713 ** abandoned and an SQLite [error code] is returned to the caller immediately.
8715 ** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
8717 ** ^This function does not set the database handle error code or message
8718 ** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
8720 int sqlite3_db_cacheflush(sqlite3*);
8723 ** CAPI3REF: The pre-update hook.
8725 ** ^These interfaces are only available if SQLite is compiled using the
8726 ** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
8728 ** ^The [sqlite3_preupdate_hook()] interface registers a callback function
8729 ** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
8730 ** on a database table.
8731 ** ^At most one preupdate hook may be registered at a time on a single
8732 ** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
8733 ** the previous setting.
8734 ** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
8735 ** with a NULL pointer as the second parameter.
8736 ** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
8737 ** the first parameter to callbacks.
8739 ** ^The preupdate hook only fires for changes to real database tables; the
8740 ** preupdate hook is not invoked for changes to [virtual tables] or to
8741 ** system tables like sqlite_master or sqlite_stat1.
8743 ** ^The second parameter to the preupdate callback is a pointer to
8744 ** the [database connection] that registered the preupdate hook.
8745 ** ^The third parameter to the preupdate callback is one of the constants
8746 ** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
8747 ** kind of update operation that is about to occur.
8748 ** ^(The fourth parameter to the preupdate callback is the name of the
8749 ** database within the database connection that is being modified. This
8750 ** will be "main" for the main database or "temp" for TEMP tables or
8751 ** the name given after the AS keyword in the [ATTACH] statement for attached
8752 ** databases.)^
8753 ** ^The fifth parameter to the preupdate callback is the name of the
8754 ** table that is being modified.
8756 ** For an UPDATE or DELETE operation on a [rowid table], the sixth
8757 ** parameter passed to the preupdate callback is the initial [rowid] of the
8758 ** row being modified or deleted. For an INSERT operation on a rowid table,
8759 ** or any operation on a WITHOUT ROWID table, the value of the sixth
8760 ** parameter is undefined. For an INSERT or UPDATE on a rowid table the
8761 ** seventh parameter is the final rowid value of the row being inserted
8762 ** or updated. The value of the seventh parameter passed to the callback
8763 ** function is not defined for operations on WITHOUT ROWID tables, or for
8764 ** INSERT operations on rowid tables.
8766 ** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
8767 ** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
8768 ** provide additional information about a preupdate event. These routines
8769 ** may only be called from within a preupdate callback. Invoking any of
8770 ** these routines from outside of a preupdate callback or with a
8771 ** [database connection] pointer that is different from the one supplied
8772 ** to the preupdate callback results in undefined and probably undesirable
8773 ** behavior.
8775 ** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
8776 ** in the row that is being inserted, updated, or deleted.
8778 ** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
8779 ** a [protected sqlite3_value] that contains the value of the Nth column of
8780 ** the table row before it is updated. The N parameter must be between 0
8781 ** and one less than the number of columns or the behavior will be
8782 ** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
8783 ** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
8784 ** behavior is undefined. The [sqlite3_value] that P points to
8785 ** will be destroyed when the preupdate callback returns.
8787 ** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
8788 ** a [protected sqlite3_value] that contains the value of the Nth column of
8789 ** the table row after it is updated. The N parameter must be between 0
8790 ** and one less than the number of columns or the behavior will be
8791 ** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
8792 ** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
8793 ** behavior is undefined. The [sqlite3_value] that P points to
8794 ** will be destroyed when the preupdate callback returns.
8796 ** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
8797 ** callback was invoked as a result of a direct insert, update, or delete
8798 ** operation; or 1 for inserts, updates, or deletes invoked by top-level
8799 ** triggers; or 2 for changes resulting from triggers called by top-level
8800 ** triggers; and so forth.
8802 ** See also: [sqlite3_update_hook()]
8804 #if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
8805 void *sqlite3_preupdate_hook(
8806 sqlite3 *db,
8807 void(*xPreUpdate)(
8808 void *pCtx, /* Copy of third arg to preupdate_hook() */
8809 sqlite3 *db, /* Database handle */
8810 int op, /* SQLITE_UPDATE, DELETE or INSERT */
8811 char const *zDb, /* Database name */
8812 char const *zName, /* Table name */
8813 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */
8814 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */
8816 void*
8818 int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
8819 int sqlite3_preupdate_count(sqlite3 *);
8820 int sqlite3_preupdate_depth(sqlite3 *);
8821 int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
8822 #endif
8825 ** CAPI3REF: Low-level system error code
8827 ** ^Attempt to return the underlying operating system error code or error
8828 ** number that caused the most recent I/O error or failure to open a file.
8829 ** The return value is OS-dependent. For example, on unix systems, after
8830 ** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
8831 ** called to get back the underlying "errno" that caused the problem, such
8832 ** as ENOSPC, EAUTH, EISDIR, and so forth.
8834 int sqlite3_system_errno(sqlite3*);
8837 ** CAPI3REF: Database Snapshot
8838 ** KEYWORDS: {snapshot} {sqlite3_snapshot}
8839 ** EXPERIMENTAL
8841 ** An instance of the snapshot object records the state of a [WAL mode]
8842 ** database for some specific point in history.
8844 ** In [WAL mode], multiple [database connections] that are open on the
8845 ** same database file can each be reading a different historical version
8846 ** of the database file. When a [database connection] begins a read
8847 ** transaction, that connection sees an unchanging copy of the database
8848 ** as it existed for the point in time when the transaction first started.
8849 ** Subsequent changes to the database from other connections are not seen
8850 ** by the reader until a new read transaction is started.
8852 ** The sqlite3_snapshot object records state information about an historical
8853 ** version of the database file so that it is possible to later open a new read
8854 ** transaction that sees that historical version of the database rather than
8855 ** the most recent version.
8857 ** The constructor for this object is [sqlite3_snapshot_get()]. The
8858 ** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer
8859 ** to an historical snapshot (if possible). The destructor for
8860 ** sqlite3_snapshot objects is [sqlite3_snapshot_free()].
8862 typedef struct sqlite3_snapshot {
8863 unsigned char hidden[48];
8864 } sqlite3_snapshot;
8867 ** CAPI3REF: Record A Database Snapshot
8868 ** EXPERIMENTAL
8870 ** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
8871 ** new [sqlite3_snapshot] object that records the current state of
8872 ** schema S in database connection D. ^On success, the
8873 ** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
8874 ** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
8875 ** If there is not already a read-transaction open on schema S when
8876 ** this function is called, one is opened automatically.
8878 ** The following must be true for this function to succeed. If any of
8879 ** the following statements are false when sqlite3_snapshot_get() is
8880 ** called, SQLITE_ERROR is returned. The final value of *P is undefined
8881 ** in this case.
8883 ** <ul>
8884 ** <li> The database handle must be in [autocommit mode].
8886 ** <li> Schema S of [database connection] D must be a [WAL mode] database.
8888 ** <li> There must not be a write transaction open on schema S of database
8889 ** connection D.
8891 ** <li> One or more transactions must have been written to the current wal
8892 ** file since it was created on disk (by any connection). This means
8893 ** that a snapshot cannot be taken on a wal mode database with no wal
8894 ** file immediately after it is first opened. At least one transaction
8895 ** must be written to it first.
8896 ** </ul>
8898 ** This function may also return SQLITE_NOMEM. If it is called with the
8899 ** database handle in autocommit mode but fails for some other reason,
8900 ** whether or not a read transaction is opened on schema S is undefined.
8902 ** The [sqlite3_snapshot] object returned from a successful call to
8903 ** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
8904 ** to avoid a memory leak.
8906 ** The [sqlite3_snapshot_get()] interface is only available when the
8907 ** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
8909 SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
8910 sqlite3 *db,
8911 const char *zSchema,
8912 sqlite3_snapshot **ppSnapshot
8916 ** CAPI3REF: Start a read transaction on an historical snapshot
8917 ** EXPERIMENTAL
8919 ** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a
8920 ** read transaction for schema S of
8921 ** [database connection] D such that the read transaction
8922 ** refers to historical [snapshot] P, rather than the most
8923 ** recent change to the database.
8924 ** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success
8925 ** or an appropriate [error code] if it fails.
8927 ** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be
8928 ** the first operation following the [BEGIN] that takes the schema S
8929 ** out of [autocommit mode].
8930 ** ^In other words, schema S must not currently be in
8931 ** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the
8932 ** database connection D must be out of [autocommit mode].
8933 ** ^A [snapshot] will fail to open if it has been overwritten by a
8934 ** [checkpoint].
8935 ** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
8936 ** database connection D does not know that the database file for
8937 ** schema S is in [WAL mode]. A database connection might not know
8938 ** that the database file is in [WAL mode] if there has been no prior
8939 ** I/O on that database connection, or if the database entered [WAL mode]
8940 ** after the most recent I/O on the database connection.)^
8941 ** (Hint: Run "[PRAGMA application_id]" against a newly opened
8942 ** database connection in order to make it ready to use snapshots.)
8944 ** The [sqlite3_snapshot_open()] interface is only available when the
8945 ** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
8947 SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
8948 sqlite3 *db,
8949 const char *zSchema,
8950 sqlite3_snapshot *pSnapshot
8954 ** CAPI3REF: Destroy a snapshot
8955 ** EXPERIMENTAL
8957 ** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
8958 ** The application must eventually free every [sqlite3_snapshot] object
8959 ** using this routine to avoid a memory leak.
8961 ** The [sqlite3_snapshot_free()] interface is only available when the
8962 ** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
8964 SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
8967 ** CAPI3REF: Compare the ages of two snapshot handles.
8968 ** EXPERIMENTAL
8970 ** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
8971 ** of two valid snapshot handles.
8973 ** If the two snapshot handles are not associated with the same database
8974 ** file, the result of the comparison is undefined.
8976 ** Additionally, the result of the comparison is only valid if both of the
8977 ** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
8978 ** last time the wal file was deleted. The wal file is deleted when the
8979 ** database is changed back to rollback mode or when the number of database
8980 ** clients drops to zero. If either snapshot handle was obtained before the
8981 ** wal file was last deleted, the value returned by this function
8982 ** is undefined.
8984 ** Otherwise, this API returns a negative value if P1 refers to an older
8985 ** snapshot than P2, zero if the two handles refer to the same database
8986 ** snapshot, and a positive value if P1 is a newer snapshot than P2.
8988 SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
8989 sqlite3_snapshot *p1,
8990 sqlite3_snapshot *p2
8994 ** CAPI3REF: Recover snapshots from a wal file
8995 ** EXPERIMENTAL
8997 ** If all connections disconnect from a database file but do not perform
8998 ** a checkpoint, the existing wal file is opened along with the database
8999 ** file the next time the database is opened. At this point it is only
9000 ** possible to successfully call sqlite3_snapshot_open() to open the most
9001 ** recent snapshot of the database (the one at the head of the wal file),
9002 ** even though the wal file may contain other valid snapshots for which
9003 ** clients have sqlite3_snapshot handles.
9005 ** This function attempts to scan the wal file associated with database zDb
9006 ** of database handle db and make all valid snapshots available to
9007 ** sqlite3_snapshot_open(). It is an error if there is already a read
9008 ** transaction open on the database, or if the database is not a wal mode
9009 ** database.
9011 ** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
9013 SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
9016 ** CAPI3REF: Serialize a database
9018 ** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory
9019 ** that is a serialization of the S database on [database connection] D.
9020 ** If P is not a NULL pointer, then the size of the database in bytes
9021 ** is written into *P.
9023 ** For an ordinary on-disk database file, the serialization is just a
9024 ** copy of the disk file. For an in-memory database or a "TEMP" database,
9025 ** the serialization is the same sequence of bytes which would be written
9026 ** to disk if that database where backed up to disk.
9028 ** The usual case is that sqlite3_serialize() copies the serialization of
9029 ** the database into memory obtained from [sqlite3_malloc64()] and returns
9030 ** a pointer to that memory. The caller is responsible for freeing the
9031 ** returned value to avoid a memory leak. However, if the F argument
9032 ** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
9033 ** are made, and the sqlite3_serialize() function will return a pointer
9034 ** to the contiguous memory representation of the database that SQLite
9035 ** is currently using for that database, or NULL if the no such contiguous
9036 ** memory representation of the database exists. A contiguous memory
9037 ** representation of the database will usually only exist if there has
9038 ** been a prior call to [sqlite3_deserialize(D,S,...)] with the same
9039 ** values of D and S.
9040 ** The size of the database is written into *P even if the
9041 ** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
9042 ** of the database exists.
9044 ** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
9045 ** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
9046 ** allocation error occurs.
9048 ** This interface is only available if SQLite is compiled with the
9049 ** [SQLITE_ENABLE_DESERIALIZE] option.
9051 unsigned char *sqlite3_serialize(
9052 sqlite3 *db, /* The database connection */
9053 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */
9054 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */
9055 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */
9059 ** CAPI3REF: Flags for sqlite3_serialize
9061 ** Zero or more of the following constants can be OR-ed together for
9062 ** the F argument to [sqlite3_serialize(D,S,P,F)].
9064 ** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return
9065 ** a pointer to contiguous in-memory database that it is currently using,
9066 ** without making a copy of the database. If SQLite is not currently using
9067 ** a contiguous in-memory database, then this option causes
9068 ** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be
9069 ** using a contiguous in-memory database if it has been initialized by a
9070 ** prior call to [sqlite3_deserialize()].
9072 #define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */
9075 ** CAPI3REF: Deserialize a database
9077 ** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
9078 ** [database connection] D to disconnect from database S and then
9079 ** reopen S as an in-memory database based on the serialization contained
9080 ** in P. The serialized database P is N bytes in size. M is the size of
9081 ** the buffer P, which might be larger than N. If M is larger than N, and
9082 ** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
9083 ** permitted to add content to the in-memory database as long as the total
9084 ** size does not exceed M bytes.
9086 ** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
9087 ** invoke sqlite3_free() on the serialization buffer when the database
9088 ** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
9089 ** SQLite will try to increase the buffer size using sqlite3_realloc64()
9090 ** if writes on the database cause it to grow larger than M bytes.
9092 ** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
9093 ** database is currently in a read transaction or is involved in a backup
9094 ** operation.
9096 ** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
9097 ** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
9098 ** [sqlite3_free()] is invoked on argument P prior to returning.
9100 ** This interface is only available if SQLite is compiled with the
9101 ** [SQLITE_ENABLE_DESERIALIZE] option.
9103 int sqlite3_deserialize(
9104 sqlite3 *db, /* The database connection */
9105 const char *zSchema, /* Which DB to reopen with the deserialization */
9106 unsigned char *pData, /* The serialized database content */
9107 sqlite3_int64 szDb, /* Number bytes in the deserialization */
9108 sqlite3_int64 szBuf, /* Total size of buffer pData[] */
9109 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */
9113 ** CAPI3REF: Flags for sqlite3_deserialize()
9115 ** The following are allowed values for 6th argument (the F argument) to
9116 ** the [sqlite3_deserialize(D,S,P,N,M,F)] interface.
9118 ** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
9119 ** in the P argument is held in memory obtained from [sqlite3_malloc64()]
9120 ** and that SQLite should take ownership of this memory and automatically
9121 ** free it when it has finished using it. Without this flag, the caller
9122 ** is resposible for freeing any dynamically allocated memory.
9124 ** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
9125 ** grow the size of the database using calls to [sqlite3_realloc64()]. This
9126 ** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
9127 ** Without this flag, the deserialized database cannot increase in size beyond
9128 ** the number of bytes specified by the M parameter.
9130 ** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
9131 ** should be treated as read-only.
9133 #define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
9134 #define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */
9135 #define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */
9138 ** Undo the hack that converts floating point types to integer for
9139 ** builds on processors without floating point support.
9141 #ifdef SQLITE_OMIT_FLOATING_POINT
9142 # undef double
9143 #endif
9145 #ifdef __cplusplus
9146 } /* End of the 'extern "C"' block */
9147 #endif
9148 #endif /* SQLITE3_H */