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1 /*
2 ** 2001 September 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 suppose to operate.
28 ** The name of this file under configuration management is "sqlite.h.in".
29 ** The makefile makes some minor changes to this file (such as inserting
30 ** the version number) and changes its name to "sqlite3.h" as
31 ** part of the build process.
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 ** Add the ability to override 'extern'
48 #ifndef SQLITE_EXTERN
49 # define SQLITE_EXTERN extern
50 #endif
53 ** These no-op macros are used in front of interfaces to mark those
54 ** interfaces as either deprecated or experimental. New applications
55 ** should not use deprecated interfaces - they are support for backwards
56 ** compatibility only. Application writers should be aware that
57 ** experimental interfaces are subject to change in point releases.
59 ** These macros used to resolve to various kinds of compiler magic that
60 ** would generate warning messages when they were used. But that
61 ** compiler magic ended up generating such a flurry of bug reports
62 ** that we have taken it all out and gone back to using simple
63 ** noop macros.
65 #define SQLITE_DEPRECATED
66 #define SQLITE_EXPERIMENTAL
69 ** Ensure these symbols were not defined by some previous header file.
71 #ifdef SQLITE_VERSION
72 # undef SQLITE_VERSION
73 #endif
74 #ifdef SQLITE_VERSION_NUMBER
75 # undef SQLITE_VERSION_NUMBER
76 #endif
79 ** CAPI3REF: Compile-Time Library Version Numbers
81 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
82 ** evaluates to a string literal that is the SQLite version in the
83 ** format "X.Y.Z" where X is the major version number (always 3 for
84 ** SQLite3) and Y is the minor version number and Z is the release number.)^
85 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
86 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
87 ** numbers used in [SQLITE_VERSION].)^
88 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
89 ** be larger than the release from which it is derived. Either Y will
90 ** be held constant and Z will be incremented or else Y will be incremented
91 ** and Z will be reset to zero.
93 ** Since version 3.6.18, SQLite source code has been stored in the
94 ** <a href="http://www.fossil-scm.org/">Fossil configuration management
95 ** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to
96 ** a string which identifies a particular check-in of SQLite
97 ** within its configuration management system. ^The SQLITE_SOURCE_ID
98 ** string contains the date and time of the check-in (UTC) and an SHA1
99 ** hash of the entire source tree.
101 ** See also: [sqlite3_libversion()],
102 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
103 ** [sqlite_version()] and [sqlite_source_id()].
105 #define SQLITE_VERSION "--VERS--"
106 #define SQLITE_VERSION_NUMBER --VERSION-NUMBER--
107 #define SQLITE_SOURCE_ID "--SOURCE-ID--"
110 ** CAPI3REF: Run-Time Library Version Numbers
111 ** KEYWORDS: sqlite3_version, sqlite3_sourceid
113 ** These interfaces provide the same information as the [SQLITE_VERSION],
114 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
115 ** but are associated with the library instead of the header file. ^(Cautious
116 ** programmers might include assert() statements in their application to
117 ** verify that values returned by these interfaces match the macros in
118 ** the header, and thus insure that the application is
119 ** compiled with matching library and header files.
121 ** <blockquote><pre>
122 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
123 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
124 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
125 ** </pre></blockquote>)^
127 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
128 ** macro. ^The sqlite3_libversion() function returns a pointer to the
129 ** to the sqlite3_version[] string constant. The sqlite3_libversion()
130 ** function is provided for use in DLLs since DLL users usually do not have
131 ** direct access to string constants within the DLL. ^The
132 ** sqlite3_libversion_number() function returns an integer equal to
133 ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns
134 ** a pointer to a string constant whose value is the same as the
135 ** [SQLITE_SOURCE_ID] C preprocessor macro.
137 ** See also: [sqlite_version()] and [sqlite_source_id()].
139 SQLITE_EXTERN const char sqlite3_version[];
140 const char *sqlite3_libversion(void);
141 const char *sqlite3_sourceid(void);
142 int sqlite3_libversion_number(void);
145 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
147 ** ^The sqlite3_compileoption_used() function returns 0 or 1
148 ** indicating whether the specified option was defined at
149 ** compile time. ^The SQLITE_ prefix may be omitted from the
150 ** option name passed to sqlite3_compileoption_used().
152 ** ^The sqlite3_compileoption_get() function allows iterating
153 ** over the list of options that were defined at compile time by
154 ** returning the N-th compile time option string. ^If N is out of range,
155 ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
156 ** prefix is omitted from any strings returned by
157 ** sqlite3_compileoption_get().
159 ** ^Support for the diagnostic functions sqlite3_compileoption_used()
160 ** and sqlite3_compileoption_get() may be omitted by specifying the
161 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
163 ** See also: SQL functions [sqlite_compileoption_used()] and
164 ** [sqlite_compileoption_get()] and the [compile_options pragma].
166 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
167 int sqlite3_compileoption_used(const char *zOptName);
168 const char *sqlite3_compileoption_get(int N);
169 #endif
172 ** CAPI3REF: Test To See If The Library Is Threadsafe
174 ** ^The sqlite3_threadsafe() function returns zero if and only if
175 ** SQLite was compiled with mutexing code omitted due to the
176 ** [SQLITE_THREADSAFE] compile-time option being set to 0.
178 ** SQLite can be compiled with or without mutexes. When
179 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
180 ** are enabled and SQLite is threadsafe. When the
181 ** [SQLITE_THREADSAFE] macro is 0,
182 ** the mutexes are omitted. Without the mutexes, it is not safe
183 ** to use SQLite concurrently from more than one thread.
185 ** Enabling mutexes incurs a measurable performance penalty.
186 ** So if speed is of utmost importance, it makes sense to disable
187 ** the mutexes. But for maximum safety, mutexes should be enabled.
188 ** ^The default behavior is for mutexes to be enabled.
190 ** This interface can be used by an application to make sure that the
191 ** version of SQLite that it is linking against was compiled with
192 ** the desired setting of the [SQLITE_THREADSAFE] macro.
194 ** This interface only reports on the compile-time mutex setting
195 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
196 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
197 ** can be fully or partially disabled using a call to [sqlite3_config()]
198 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
199 ** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the
200 ** sqlite3_threadsafe() function shows only the compile-time setting of
201 ** thread safety, not any run-time changes to that setting made by
202 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
203 ** is unchanged by calls to sqlite3_config().)^
205 ** See the [threading mode] documentation for additional information.
207 int sqlite3_threadsafe(void);
210 ** CAPI3REF: Database Connection Handle
211 ** KEYWORDS: {database connection} {database connections}
213 ** Each open SQLite database is represented by a pointer to an instance of
214 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3
215 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
216 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
217 ** and [sqlite3_close_v2()] are its destructors. There are many other
218 ** interfaces (such as
219 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
220 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
221 ** sqlite3 object.
223 typedef struct sqlite3 sqlite3;
226 ** CAPI3REF: 64-Bit Integer Types
227 ** KEYWORDS: sqlite_int64 sqlite_uint64
229 ** Because there is no cross-platform way to specify 64-bit integer types
230 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
232 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
233 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
234 ** compatibility only.
236 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
237 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
238 ** sqlite3_uint64 and sqlite_uint64 types can store integer values
239 ** between 0 and +18446744073709551615 inclusive.
241 #ifdef SQLITE_INT64_TYPE
242 typedef SQLITE_INT64_TYPE sqlite_int64;
243 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
244 #elif defined(_MSC_VER) || defined(__BORLANDC__)
245 typedef __int64 sqlite_int64;
246 typedef unsigned __int64 sqlite_uint64;
247 #else
248 typedef long long int sqlite_int64;
249 typedef unsigned long long int sqlite_uint64;
250 #endif
251 typedef sqlite_int64 sqlite3_int64;
252 typedef sqlite_uint64 sqlite3_uint64;
255 ** If compiling for a processor that lacks floating point support,
256 ** substitute integer for floating-point.
258 #ifdef SQLITE_OMIT_FLOATING_POINT
259 # define double sqlite3_int64
260 #endif
263 ** CAPI3REF: Closing A Database Connection
265 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
266 ** for the [sqlite3] object.
267 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
268 ** the [sqlite3] object is successfully destroyed and all associated
269 ** resources are deallocated.
271 ** ^If the database connection is associated with unfinalized prepared
272 ** statements or unfinished sqlite3_backup objects then sqlite3_close()
273 ** will leave the database connection open and return [SQLITE_BUSY].
274 ** ^If sqlite3_close_v2() is called with unfinalized prepared statements
275 ** and/or unfinished sqlite3_backups, then the database connection becomes
276 ** an unusable "zombie" which will automatically be deallocated when the
277 ** last prepared statement is finalized or the last sqlite3_backup is
278 ** finished. The sqlite3_close_v2() interface is intended for use with
279 ** host languages that are garbage collected, and where the order in which
280 ** destructors are called is arbitrary.
282 ** Applications should [sqlite3_finalize | finalize] all [prepared statements],
283 ** [sqlite3_blob_close | close] all [BLOB handles], and
284 ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
285 ** with the [sqlite3] object prior to attempting to close the object. ^If
286 ** sqlite3_close_v2() is called on a [database connection] that still has
287 ** outstanding [prepared statements], [BLOB handles], and/or
288 ** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
289 ** of resources is deferred until all [prepared statements], [BLOB handles],
290 ** and [sqlite3_backup] objects are also destroyed.
292 ** ^If an [sqlite3] object is destroyed while a transaction is open,
293 ** the transaction is automatically rolled back.
295 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
296 ** must be either a NULL
297 ** pointer or an [sqlite3] object pointer obtained
298 ** from [sqlite3_open()], [sqlite3_open16()], or
299 ** [sqlite3_open_v2()], and not previously closed.
300 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
301 ** argument is a harmless no-op.
303 int sqlite3_close(sqlite3*);
304 int sqlite3_close_v2(sqlite3*);
307 ** The type for a callback function.
308 ** This is legacy and deprecated. It is included for historical
309 ** compatibility and is not documented.
311 typedef int (*sqlite3_callback)(void*,int,char**, char**);
314 ** CAPI3REF: One-Step Query Execution Interface
316 ** The sqlite3_exec() interface is a convenience wrapper around
317 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
318 ** that allows an application to run multiple statements of SQL
319 ** without having to use a lot of C code.
321 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
322 ** semicolon-separate SQL statements passed into its 2nd argument,
323 ** in the context of the [database connection] passed in as its 1st
324 ** argument. ^If the callback function of the 3rd argument to
325 ** sqlite3_exec() is not NULL, then it is invoked for each result row
326 ** coming out of the evaluated SQL statements. ^The 4th argument to
327 ** sqlite3_exec() is relayed through to the 1st argument of each
328 ** callback invocation. ^If the callback pointer to sqlite3_exec()
329 ** is NULL, then no callback is ever invoked and result rows are
330 ** ignored.
332 ** ^If an error occurs while evaluating the SQL statements passed into
333 ** sqlite3_exec(), then execution of the current statement stops and
334 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
335 ** is not NULL then any error message is written into memory obtained
336 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
337 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
338 ** on error message strings returned through the 5th parameter of
339 ** of sqlite3_exec() after the error message string is no longer needed.
340 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
341 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
342 ** NULL before returning.
344 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
345 ** routine returns SQLITE_ABORT without invoking the callback again and
346 ** without running any subsequent SQL statements.
348 ** ^The 2nd argument to the sqlite3_exec() callback function is the
349 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
350 ** callback is an array of pointers to strings obtained as if from
351 ** [sqlite3_column_text()], one for each column. ^If an element of a
352 ** result row is NULL then the corresponding string pointer for the
353 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
354 ** sqlite3_exec() callback is an array of pointers to strings where each
355 ** entry represents the name of corresponding result column as obtained
356 ** from [sqlite3_column_name()].
358 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
359 ** to an empty string, or a pointer that contains only whitespace and/or
360 ** SQL comments, then no SQL statements are evaluated and the database
361 ** is not changed.
363 ** Restrictions:
365 ** <ul>
366 ** <li> The application must insure that the 1st parameter to sqlite3_exec()
367 ** is a valid and open [database connection].
368 ** <li> The application must not close the [database connection] specified by
369 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
370 ** <li> The application must not modify the SQL statement text passed into
371 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
372 ** </ul>
374 int sqlite3_exec(
375 sqlite3*, /* An open database */
376 const char *sql, /* SQL to be evaluated */
377 int (*callback)(void*,int,char**,char**), /* Callback function */
378 void *, /* 1st argument to callback */
379 char **errmsg /* Error msg written here */
383 ** CAPI3REF: Result Codes
384 ** KEYWORDS: {result code definitions}
386 ** Many SQLite functions return an integer result code from the set shown
387 ** here in order to indicate success or failure.
389 ** New error codes may be added in future versions of SQLite.
391 ** See also: [extended result code definitions]
393 #define SQLITE_OK 0 /* Successful result */
394 /* beginning-of-error-codes */
395 #define SQLITE_ERROR 1 /* SQL error or missing database */
396 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
397 #define SQLITE_PERM 3 /* Access permission denied */
398 #define SQLITE_ABORT 4 /* Callback routine requested an abort */
399 #define SQLITE_BUSY 5 /* The database file is locked */
400 #define SQLITE_LOCKED 6 /* A table in the database is locked */
401 #define SQLITE_NOMEM 7 /* A malloc() failed */
402 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */
403 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
404 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
405 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */
406 #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
407 #define SQLITE_FULL 13 /* Insertion failed because database is full */
408 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */
409 #define SQLITE_PROTOCOL 15 /* Database lock protocol error */
410 #define SQLITE_EMPTY 16 /* Database is empty */
411 #define SQLITE_SCHEMA 17 /* The database schema changed */
412 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
413 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
414 #define SQLITE_MISMATCH 20 /* Data type mismatch */
415 #define SQLITE_MISUSE 21 /* Library used incorrectly */
416 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
417 #define SQLITE_AUTH 23 /* Authorization denied */
418 #define SQLITE_FORMAT 24 /* Auxiliary database format error */
419 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
420 #define SQLITE_NOTADB 26 /* File opened that is not a database file */
421 #define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */
422 #define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */
423 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
424 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
425 /* end-of-error-codes */
428 ** CAPI3REF: Extended Result Codes
429 ** KEYWORDS: {extended result code definitions}
431 ** In its default configuration, SQLite API routines return one of 30 integer
432 ** [result codes]. However, experience has shown that many of
433 ** these result codes are too coarse-grained. They do not provide as
434 ** much information about problems as programmers might like. In an effort to
435 ** address this, newer versions of SQLite (version 3.3.8 and later) include
436 ** support for additional result codes that provide more detailed information
437 ** about errors. These [extended result codes] are enabled or disabled
438 ** on a per database connection basis using the
439 ** [sqlite3_extended_result_codes()] API. Or, the extended code for
440 ** the most recent error can be obtained using
441 ** [sqlite3_extended_errcode()].
443 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
444 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
445 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
446 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
447 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
448 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
449 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
450 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
451 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
452 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
453 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
454 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
455 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
456 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
457 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
458 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
459 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
460 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
461 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
462 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
463 #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
464 #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
465 #define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
466 #define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
467 #define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8))
468 #define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8))
469 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
470 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
471 #define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8))
472 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
473 #define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
474 #define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
475 #define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8))
476 #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
477 #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
478 #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
479 #define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8))
480 #define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8))
481 #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
482 #define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8))
483 #define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8))
484 #define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8))
485 #define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8))
486 #define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8))
487 #define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8))
488 #define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8))
489 #define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8))
490 #define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8))
491 #define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8))
492 #define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8))
493 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
494 #define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8))
495 #define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8))
498 ** CAPI3REF: Flags For File Open Operations
500 ** These bit values are intended for use in the
501 ** 3rd parameter to the [sqlite3_open_v2()] interface and
502 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
504 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
505 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
506 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
507 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
508 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
509 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
510 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
511 #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
512 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
513 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
514 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
515 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
516 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
517 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
518 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
519 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
520 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
521 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
522 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
523 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
525 /* Reserved: 0x00F00000 */
528 ** CAPI3REF: Device Characteristics
530 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
531 ** object returns an integer which is a vector of these
532 ** bit values expressing I/O characteristics of the mass storage
533 ** device that holds the file that the [sqlite3_io_methods]
534 ** refers to.
536 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
537 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
538 ** mean that writes of blocks that are nnn bytes in size and
539 ** are aligned to an address which is an integer multiple of
540 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
541 ** that when data is appended to a file, the data is appended
542 ** first then the size of the file is extended, never the other
543 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
544 ** information is written to disk in the same order as calls
545 ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
546 ** after reboot following a crash or power loss, the only bytes in a
547 ** file that were written at the application level might have changed
548 ** and that adjacent bytes, even bytes within the same sector are
549 ** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
550 ** flag indicate that a file cannot be deleted when open. The
551 ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
552 ** read-only media and cannot be changed even by processes with
553 ** elevated privileges.
555 #define SQLITE_IOCAP_ATOMIC 0x00000001
556 #define SQLITE_IOCAP_ATOMIC512 0x00000002
557 #define SQLITE_IOCAP_ATOMIC1K 0x00000004
558 #define SQLITE_IOCAP_ATOMIC2K 0x00000008
559 #define SQLITE_IOCAP_ATOMIC4K 0x00000010
560 #define SQLITE_IOCAP_ATOMIC8K 0x00000020
561 #define SQLITE_IOCAP_ATOMIC16K 0x00000040
562 #define SQLITE_IOCAP_ATOMIC32K 0x00000080
563 #define SQLITE_IOCAP_ATOMIC64K 0x00000100
564 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
565 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
566 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
567 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
568 #define SQLITE_IOCAP_IMMUTABLE 0x00002000
571 ** CAPI3REF: File Locking Levels
573 ** SQLite uses one of these integer values as the second
574 ** argument to calls it makes to the xLock() and xUnlock() methods
575 ** of an [sqlite3_io_methods] object.
577 #define SQLITE_LOCK_NONE 0
578 #define SQLITE_LOCK_SHARED 1
579 #define SQLITE_LOCK_RESERVED 2
580 #define SQLITE_LOCK_PENDING 3
581 #define SQLITE_LOCK_EXCLUSIVE 4
584 ** CAPI3REF: Synchronization Type Flags
586 ** When SQLite invokes the xSync() method of an
587 ** [sqlite3_io_methods] object it uses a combination of
588 ** these integer values as the second argument.
590 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
591 ** sync operation only needs to flush data to mass storage. Inode
592 ** information need not be flushed. If the lower four bits of the flag
593 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
594 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
595 ** to use Mac OS X style fullsync instead of fsync().
597 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
598 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
599 ** settings. The [synchronous pragma] determines when calls to the
600 ** xSync VFS method occur and applies uniformly across all platforms.
601 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
602 ** energetic or rigorous or forceful the sync operations are and
603 ** only make a difference on Mac OSX for the default SQLite code.
604 ** (Third-party VFS implementations might also make the distinction
605 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
606 ** operating systems natively supported by SQLite, only Mac OSX
607 ** cares about the difference.)
609 #define SQLITE_SYNC_NORMAL 0x00002
610 #define SQLITE_SYNC_FULL 0x00003
611 #define SQLITE_SYNC_DATAONLY 0x00010
614 ** CAPI3REF: OS Interface Open File Handle
616 ** An [sqlite3_file] object represents an open file in the
617 ** [sqlite3_vfs | OS interface layer]. Individual OS interface
618 ** implementations will
619 ** want to subclass this object by appending additional fields
620 ** for their own use. The pMethods entry is a pointer to an
621 ** [sqlite3_io_methods] object that defines methods for performing
622 ** I/O operations on the open file.
624 typedef struct sqlite3_file sqlite3_file;
625 struct sqlite3_file {
626 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
630 ** CAPI3REF: OS Interface File Virtual Methods Object
632 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
633 ** [sqlite3_file] object (or, more commonly, a subclass of the
634 ** [sqlite3_file] object) with a pointer to an instance of this object.
635 ** This object defines the methods used to perform various operations
636 ** against the open file represented by the [sqlite3_file] object.
638 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
639 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
640 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
641 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
642 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
643 ** to NULL.
645 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
646 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
647 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
648 ** flag may be ORed in to indicate that only the data of the file
649 ** and not its inode needs to be synced.
651 ** The integer values to xLock() and xUnlock() are one of
652 ** <ul>
653 ** <li> [SQLITE_LOCK_NONE],
654 ** <li> [SQLITE_LOCK_SHARED],
655 ** <li> [SQLITE_LOCK_RESERVED],
656 ** <li> [SQLITE_LOCK_PENDING], or
657 ** <li> [SQLITE_LOCK_EXCLUSIVE].
658 ** </ul>
659 ** xLock() increases the lock. xUnlock() decreases the lock.
660 ** The xCheckReservedLock() method checks whether any database connection,
661 ** either in this process or in some other process, is holding a RESERVED,
662 ** PENDING, or EXCLUSIVE lock on the file. It returns true
663 ** if such a lock exists and false otherwise.
665 ** The xFileControl() method is a generic interface that allows custom
666 ** VFS implementations to directly control an open file using the
667 ** [sqlite3_file_control()] interface. The second "op" argument is an
668 ** integer opcode. The third argument is a generic pointer intended to
669 ** point to a structure that may contain arguments or space in which to
670 ** write return values. Potential uses for xFileControl() might be
671 ** functions to enable blocking locks with timeouts, to change the
672 ** locking strategy (for example to use dot-file locks), to inquire
673 ** about the status of a lock, or to break stale locks. The SQLite
674 ** core reserves all opcodes less than 100 for its own use.
675 ** A [file control opcodes | list of opcodes] less than 100 is available.
676 ** Applications that define a custom xFileControl method should use opcodes
677 ** greater than 100 to avoid conflicts. VFS implementations should
678 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
679 ** recognize.
681 ** The xSectorSize() method returns the sector size of the
682 ** device that underlies the file. The sector size is the
683 ** minimum write that can be performed without disturbing
684 ** other bytes in the file. The xDeviceCharacteristics()
685 ** method returns a bit vector describing behaviors of the
686 ** underlying device:
688 ** <ul>
689 ** <li> [SQLITE_IOCAP_ATOMIC]
690 ** <li> [SQLITE_IOCAP_ATOMIC512]
691 ** <li> [SQLITE_IOCAP_ATOMIC1K]
692 ** <li> [SQLITE_IOCAP_ATOMIC2K]
693 ** <li> [SQLITE_IOCAP_ATOMIC4K]
694 ** <li> [SQLITE_IOCAP_ATOMIC8K]
695 ** <li> [SQLITE_IOCAP_ATOMIC16K]
696 ** <li> [SQLITE_IOCAP_ATOMIC32K]
697 ** <li> [SQLITE_IOCAP_ATOMIC64K]
698 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
699 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
700 ** </ul>
702 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
703 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
704 ** mean that writes of blocks that are nnn bytes in size and
705 ** are aligned to an address which is an integer multiple of
706 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
707 ** that when data is appended to a file, the data is appended
708 ** first then the size of the file is extended, never the other
709 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
710 ** information is written to disk in the same order as calls
711 ** to xWrite().
713 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
714 ** in the unread portions of the buffer with zeros. A VFS that
715 ** fails to zero-fill short reads might seem to work. However,
716 ** failure to zero-fill short reads will eventually lead to
717 ** database corruption.
719 typedef struct sqlite3_io_methods sqlite3_io_methods;
720 struct sqlite3_io_methods {
721 int iVersion;
722 int (*xClose)(sqlite3_file*);
723 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
724 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
725 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
726 int (*xSync)(sqlite3_file*, int flags);
727 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
728 int (*xLock)(sqlite3_file*, int);
729 int (*xUnlock)(sqlite3_file*, int);
730 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
731 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
732 int (*xSectorSize)(sqlite3_file*);
733 int (*xDeviceCharacteristics)(sqlite3_file*);
734 /* Methods above are valid for version 1 */
735 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
736 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
737 void (*xShmBarrier)(sqlite3_file*);
738 int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
739 /* Methods above are valid for version 2 */
740 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
741 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
742 /* Methods above are valid for version 3 */
743 /* Additional methods may be added in future releases */
747 ** CAPI3REF: Standard File Control Opcodes
748 ** KEYWORDS: {file control opcodes} {file control opcode}
750 ** These integer constants are opcodes for the xFileControl method
751 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
752 ** interface.
754 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
755 ** opcode causes the xFileControl method to write the current state of
756 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
757 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
758 ** into an integer that the pArg argument points to. This capability
759 ** is used during testing and only needs to be supported when SQLITE_TEST
760 ** is defined.
761 ** <ul>
762 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
763 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
764 ** layer a hint of how large the database file will grow to be during the
765 ** current transaction. This hint is not guaranteed to be accurate but it
766 ** is often close. The underlying VFS might choose to preallocate database
767 ** file space based on this hint in order to help writes to the database
768 ** file run faster.
770 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
771 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
772 ** extends and truncates the database file in chunks of a size specified
773 ** by the user. The fourth argument to [sqlite3_file_control()] should
774 ** point to an integer (type int) containing the new chunk-size to use
775 ** for the nominated database. Allocating database file space in large
776 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
777 ** improve performance on some systems.
779 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
780 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
781 ** to the [sqlite3_file] object associated with a particular database
782 ** connection. See the [sqlite3_file_control()] documentation for
783 ** additional information.
785 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
786 ** No longer in use.
788 ** <li>[[SQLITE_FCNTL_SYNC]]
789 ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
790 ** sent to the VFS immediately before the xSync method is invoked on a
791 ** database file descriptor. Or, if the xSync method is not invoked
792 ** because the user has configured SQLite with
793 ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
794 ** of the xSync method. In most cases, the pointer argument passed with
795 ** this file-control is NULL. However, if the database file is being synced
796 ** as part of a multi-database commit, the argument points to a nul-terminated
797 ** string containing the transactions master-journal file name. VFSes that
798 ** do not need this signal should silently ignore this opcode. Applications
799 ** should not call [sqlite3_file_control()] with this opcode as doing so may
800 ** disrupt the operation of the specialized VFSes that do require it.
802 ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
803 ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
804 ** and sent to the VFS after a transaction has been committed immediately
805 ** but before the database is unlocked. VFSes that do not need this signal
806 ** should silently ignore this opcode. Applications should not call
807 ** [sqlite3_file_control()] with this opcode as doing so may disrupt the
808 ** operation of the specialized VFSes that do require it.
810 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
811 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
812 ** retry counts and intervals for certain disk I/O operations for the
813 ** windows [VFS] in order to provide robustness in the presence of
814 ** anti-virus programs. By default, the windows VFS will retry file read,
815 ** file write, and file delete operations up to 10 times, with a delay
816 ** of 25 milliseconds before the first retry and with the delay increasing
817 ** by an additional 25 milliseconds with each subsequent retry. This
818 ** opcode allows these two values (10 retries and 25 milliseconds of delay)
819 ** to be adjusted. The values are changed for all database connections
820 ** within the same process. The argument is a pointer to an array of two
821 ** integers where the first integer i the new retry count and the second
822 ** integer is the delay. If either integer is negative, then the setting
823 ** is not changed but instead the prior value of that setting is written
824 ** into the array entry, allowing the current retry settings to be
825 ** interrogated. The zDbName parameter is ignored.
827 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
828 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
829 ** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
830 ** write ahead log and shared memory files used for transaction control
831 ** are automatically deleted when the latest connection to the database
832 ** closes. Setting persistent WAL mode causes those files to persist after
833 ** close. Persisting the files is useful when other processes that do not
834 ** have write permission on the directory containing the database file want
835 ** to read the database file, as the WAL and shared memory files must exist
836 ** in order for the database to be readable. The fourth parameter to
837 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
838 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
839 ** WAL mode. If the integer is -1, then it is overwritten with the current
840 ** WAL persistence setting.
842 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
843 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
844 ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
845 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
846 ** xDeviceCharacteristics methods. The fourth parameter to
847 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
848 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
849 ** mode. If the integer is -1, then it is overwritten with the current
850 ** zero-damage mode setting.
852 ** <li>[[SQLITE_FCNTL_OVERWRITE]]
853 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
854 ** a write transaction to indicate that, unless it is rolled back for some
855 ** reason, the entire database file will be overwritten by the current
856 ** transaction. This is used by VACUUM operations.
858 ** <li>[[SQLITE_FCNTL_VFSNAME]]
859 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
860 ** all [VFSes] in the VFS stack. The names are of all VFS shims and the
861 ** final bottom-level VFS are written into memory obtained from
862 ** [sqlite3_malloc()] and the result is stored in the char* variable
863 ** that the fourth parameter of [sqlite3_file_control()] points to.
864 ** The caller is responsible for freeing the memory when done. As with
865 ** all file-control actions, there is no guarantee that this will actually
866 ** do anything. Callers should initialize the char* variable to a NULL
867 ** pointer in case this file-control is not implemented. This file-control
868 ** is intended for diagnostic use only.
870 ** <li>[[SQLITE_FCNTL_PRAGMA]]
871 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
872 ** file control is sent to the open [sqlite3_file] object corresponding
873 ** to the database file to which the pragma statement refers. ^The argument
874 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
875 ** pointers to strings (char**) in which the second element of the array
876 ** is the name of the pragma and the third element is the argument to the
877 ** pragma or NULL if the pragma has no argument. ^The handler for an
878 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
879 ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
880 ** or the equivalent and that string will become the result of the pragma or
881 ** the error message if the pragma fails. ^If the
882 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
883 ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
884 ** file control returns [SQLITE_OK], then the parser assumes that the
885 ** VFS has handled the PRAGMA itself and the parser generates a no-op
886 ** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns
887 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
888 ** that the VFS encountered an error while handling the [PRAGMA] and the
889 ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
890 ** file control occurs at the beginning of pragma statement analysis and so
891 ** it is able to override built-in [PRAGMA] statements.
893 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
894 ** ^The [SQLITE_FCNTL_BUSYHANDLER]
895 ** file-control may be invoked by SQLite on the database file handle
896 ** shortly after it is opened in order to provide a custom VFS with access
897 ** to the connections busy-handler callback. The argument is of type (void **)
898 ** - an array of two (void *) values. The first (void *) actually points
899 ** to a function of type (int (*)(void *)). In order to invoke the connections
900 ** busy-handler, this function should be invoked with the second (void *) in
901 ** the array as the only argument. If it returns non-zero, then the operation
902 ** should be retried. If it returns zero, the custom VFS should abandon the
903 ** current operation.
905 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
906 ** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
907 ** to have SQLite generate a
908 ** temporary filename using the same algorithm that is followed to generate
909 ** temporary filenames for TEMP tables and other internal uses. The
910 ** argument should be a char** which will be filled with the filename
911 ** written into memory obtained from [sqlite3_malloc()]. The caller should
912 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
914 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
915 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
916 ** maximum number of bytes that will be used for memory-mapped I/O.
917 ** The argument is a pointer to a value of type sqlite3_int64 that
918 ** is an advisory maximum number of bytes in the file to memory map. The
919 ** pointer is overwritten with the old value. The limit is not changed if
920 ** the value originally pointed to is negative, and so the current limit
921 ** can be queried by passing in a pointer to a negative number. This
922 ** file-control is used internally to implement [PRAGMA mmap_size].
924 ** <li>[[SQLITE_FCNTL_TRACE]]
925 ** The [SQLITE_FCNTL_TRACE] file control provides advisory information
926 ** to the VFS about what the higher layers of the SQLite stack are doing.
927 ** This file control is used by some VFS activity tracing [shims].
928 ** The argument is a zero-terminated string. Higher layers in the
929 ** SQLite stack may generate instances of this file control if
930 ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
932 ** <li>[[SQLITE_FCNTL_HAS_MOVED]]
933 ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
934 ** pointer to an integer and it writes a boolean into that integer depending
935 ** on whether or not the file has been renamed, moved, or deleted since it
936 ** was first opened.
938 ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
939 ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This
940 ** opcode causes the xFileControl method to swap the file handle with the one
941 ** pointed to by the pArg argument. This capability is used during testing
942 ** and only needs to be supported when SQLITE_TEST is defined.
944 ** </ul>
946 #define SQLITE_FCNTL_LOCKSTATE 1
947 #define SQLITE_GET_LOCKPROXYFILE 2
948 #define SQLITE_SET_LOCKPROXYFILE 3
949 #define SQLITE_LAST_ERRNO 4
950 #define SQLITE_FCNTL_SIZE_HINT 5
951 #define SQLITE_FCNTL_CHUNK_SIZE 6
952 #define SQLITE_FCNTL_FILE_POINTER 7
953 #define SQLITE_FCNTL_SYNC_OMITTED 8
954 #define SQLITE_FCNTL_WIN32_AV_RETRY 9
955 #define SQLITE_FCNTL_PERSIST_WAL 10
956 #define SQLITE_FCNTL_OVERWRITE 11
957 #define SQLITE_FCNTL_VFSNAME 12
958 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
959 #define SQLITE_FCNTL_PRAGMA 14
960 #define SQLITE_FCNTL_BUSYHANDLER 15
961 #define SQLITE_FCNTL_TEMPFILENAME 16
962 #define SQLITE_FCNTL_MMAP_SIZE 18
963 #define SQLITE_FCNTL_TRACE 19
964 #define SQLITE_FCNTL_HAS_MOVED 20
965 #define SQLITE_FCNTL_SYNC 21
966 #define SQLITE_FCNTL_COMMIT_PHASETWO 22
967 #define SQLITE_FCNTL_WIN32_SET_HANDLE 23
970 ** CAPI3REF: Mutex Handle
972 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
973 ** abstract type for a mutex object. The SQLite core never looks
974 ** at the internal representation of an [sqlite3_mutex]. It only
975 ** deals with pointers to the [sqlite3_mutex] object.
977 ** Mutexes are created using [sqlite3_mutex_alloc()].
979 typedef struct sqlite3_mutex sqlite3_mutex;
982 ** CAPI3REF: OS Interface Object
984 ** An instance of the sqlite3_vfs object defines the interface between
985 ** the SQLite core and the underlying operating system. The "vfs"
986 ** in the name of the object stands for "virtual file system". See
987 ** the [VFS | VFS documentation] for further information.
989 ** The value of the iVersion field is initially 1 but may be larger in
990 ** future versions of SQLite. Additional fields may be appended to this
991 ** object when the iVersion value is increased. Note that the structure
992 ** of the sqlite3_vfs object changes in the transaction between
993 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
994 ** modified.
996 ** The szOsFile field is the size of the subclassed [sqlite3_file]
997 ** structure used by this VFS. mxPathname is the maximum length of
998 ** a pathname in this VFS.
1000 ** Registered sqlite3_vfs objects are kept on a linked list formed by
1001 ** the pNext pointer. The [sqlite3_vfs_register()]
1002 ** and [sqlite3_vfs_unregister()] interfaces manage this list
1003 ** in a thread-safe way. The [sqlite3_vfs_find()] interface
1004 ** searches the list. Neither the application code nor the VFS
1005 ** implementation should use the pNext pointer.
1007 ** The pNext field is the only field in the sqlite3_vfs
1008 ** structure that SQLite will ever modify. SQLite will only access
1009 ** or modify this field while holding a particular static mutex.
1010 ** The application should never modify anything within the sqlite3_vfs
1011 ** object once the object has been registered.
1013 ** The zName field holds the name of the VFS module. The name must
1014 ** be unique across all VFS modules.
1016 ** [[sqlite3_vfs.xOpen]]
1017 ** ^SQLite guarantees that the zFilename parameter to xOpen
1018 ** is either a NULL pointer or string obtained
1019 ** from xFullPathname() with an optional suffix added.
1020 ** ^If a suffix is added to the zFilename parameter, it will
1021 ** consist of a single "-" character followed by no more than
1022 ** 11 alphanumeric and/or "-" characters.
1023 ** ^SQLite further guarantees that
1024 ** the string will be valid and unchanged until xClose() is
1025 ** called. Because of the previous sentence,
1026 ** the [sqlite3_file] can safely store a pointer to the
1027 ** filename if it needs to remember the filename for some reason.
1028 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1029 ** must invent its own temporary name for the file. ^Whenever the
1030 ** xFilename parameter is NULL it will also be the case that the
1031 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1033 ** The flags argument to xOpen() includes all bits set in
1034 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
1035 ** or [sqlite3_open16()] is used, then flags includes at least
1036 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1037 ** If xOpen() opens a file read-only then it sets *pOutFlags to
1038 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
1040 ** ^(SQLite will also add one of the following flags to the xOpen()
1041 ** call, depending on the object being opened:
1043 ** <ul>
1044 ** <li> [SQLITE_OPEN_MAIN_DB]
1045 ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
1046 ** <li> [SQLITE_OPEN_TEMP_DB]
1047 ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
1048 ** <li> [SQLITE_OPEN_TRANSIENT_DB]
1049 ** <li> [SQLITE_OPEN_SUBJOURNAL]
1050 ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
1051 ** <li> [SQLITE_OPEN_WAL]
1052 ** </ul>)^
1054 ** The file I/O implementation can use the object type flags to
1055 ** change the way it deals with files. For example, an application
1056 ** that does not care about crash recovery or rollback might make
1057 ** the open of a journal file a no-op. Writes to this journal would
1058 ** also be no-ops, and any attempt to read the journal would return
1059 ** SQLITE_IOERR. Or the implementation might recognize that a database
1060 ** file will be doing page-aligned sector reads and writes in a random
1061 ** order and set up its I/O subsystem accordingly.
1063 ** SQLite might also add one of the following flags to the xOpen method:
1065 ** <ul>
1066 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
1067 ** <li> [SQLITE_OPEN_EXCLUSIVE]
1068 ** </ul>
1070 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1071 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1072 ** will be set for TEMP databases and their journals, transient
1073 ** databases, and subjournals.
1075 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1076 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1077 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1078 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1079 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1080 ** be created, and that it is an error if it already exists.
1081 ** It is <i>not</i> used to indicate the file should be opened
1082 ** for exclusive access.
1084 ** ^At least szOsFile bytes of memory are allocated by SQLite
1085 ** to hold the [sqlite3_file] structure passed as the third
1086 ** argument to xOpen. The xOpen method does not have to
1087 ** allocate the structure; it should just fill it in. Note that
1088 ** the xOpen method must set the sqlite3_file.pMethods to either
1089 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1090 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1091 ** element will be valid after xOpen returns regardless of the success
1092 ** or failure of the xOpen call.
1094 ** [[sqlite3_vfs.xAccess]]
1095 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1096 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1097 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1098 ** to test whether a file is at least readable. The file can be a
1099 ** directory.
1101 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1102 ** output buffer xFullPathname. The exact size of the output buffer
1103 ** is also passed as a parameter to both methods. If the output buffer
1104 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1105 ** handled as a fatal error by SQLite, vfs implementations should endeavor
1106 ** to prevent this by setting mxPathname to a sufficiently large value.
1108 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1109 ** interfaces are not strictly a part of the filesystem, but they are
1110 ** included in the VFS structure for completeness.
1111 ** The xRandomness() function attempts to return nBytes bytes
1112 ** of good-quality randomness into zOut. The return value is
1113 ** the actual number of bytes of randomness obtained.
1114 ** The xSleep() method causes the calling thread to sleep for at
1115 ** least the number of microseconds given. ^The xCurrentTime()
1116 ** method returns a Julian Day Number for the current date and time as
1117 ** a floating point value.
1118 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1119 ** Day Number multiplied by 86400000 (the number of milliseconds in
1120 ** a 24-hour day).
1121 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1122 ** date and time if that method is available (if iVersion is 2 or
1123 ** greater and the function pointer is not NULL) and will fall back
1124 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1126 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1127 ** are not used by the SQLite core. These optional interfaces are provided
1128 ** by some VFSes to facilitate testing of the VFS code. By overriding
1129 ** system calls with functions under its control, a test program can
1130 ** simulate faults and error conditions that would otherwise be difficult
1131 ** or impossible to induce. The set of system calls that can be overridden
1132 ** varies from one VFS to another, and from one version of the same VFS to the
1133 ** next. Applications that use these interfaces must be prepared for any
1134 ** or all of these interfaces to be NULL or for their behavior to change
1135 ** from one release to the next. Applications must not attempt to access
1136 ** any of these methods if the iVersion of the VFS is less than 3.
1138 typedef struct sqlite3_vfs sqlite3_vfs;
1139 typedef void (*sqlite3_syscall_ptr)(void);
1140 struct sqlite3_vfs {
1141 int iVersion; /* Structure version number (currently 3) */
1142 int szOsFile; /* Size of subclassed sqlite3_file */
1143 int mxPathname; /* Maximum file pathname length */
1144 sqlite3_vfs *pNext; /* Next registered VFS */
1145 const char *zName; /* Name of this virtual file system */
1146 void *pAppData; /* Pointer to application-specific data */
1147 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1148 int flags, int *pOutFlags);
1149 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1150 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1151 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1152 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1153 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1154 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1155 void (*xDlClose)(sqlite3_vfs*, void*);
1156 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1157 int (*xSleep)(sqlite3_vfs*, int microseconds);
1158 int (*xCurrentTime)(sqlite3_vfs*, double*);
1159 int (*xGetLastError)(sqlite3_vfs*, int, char *);
1161 ** The methods above are in version 1 of the sqlite_vfs object
1162 ** definition. Those that follow are added in version 2 or later
1164 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1166 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1167 ** Those below are for version 3 and greater.
1169 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1170 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1171 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1173 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1174 ** New fields may be appended in figure versions. The iVersion
1175 ** value will increment whenever this happens.
1180 ** CAPI3REF: Flags for the xAccess VFS method
1182 ** These integer constants can be used as the third parameter to
1183 ** the xAccess method of an [sqlite3_vfs] object. They determine
1184 ** what kind of permissions the xAccess method is looking for.
1185 ** With SQLITE_ACCESS_EXISTS, the xAccess method
1186 ** simply checks whether the file exists.
1187 ** With SQLITE_ACCESS_READWRITE, the xAccess method
1188 ** checks whether the named directory is both readable and writable
1189 ** (in other words, if files can be added, removed, and renamed within
1190 ** the directory).
1191 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1192 ** [temp_store_directory pragma], though this could change in a future
1193 ** release of SQLite.
1194 ** With SQLITE_ACCESS_READ, the xAccess method
1195 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1196 ** currently unused, though it might be used in a future release of
1197 ** SQLite.
1199 #define SQLITE_ACCESS_EXISTS 0
1200 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1201 #define SQLITE_ACCESS_READ 2 /* Unused */
1204 ** CAPI3REF: Flags for the xShmLock VFS method
1206 ** These integer constants define the various locking operations
1207 ** allowed by the xShmLock method of [sqlite3_io_methods]. The
1208 ** following are the only legal combinations of flags to the
1209 ** xShmLock method:
1211 ** <ul>
1212 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1213 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1214 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1215 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1216 ** </ul>
1218 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1219 ** was given no the corresponding lock.
1221 ** The xShmLock method can transition between unlocked and SHARED or
1222 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1223 ** and EXCLUSIVE.
1225 #define SQLITE_SHM_UNLOCK 1
1226 #define SQLITE_SHM_LOCK 2
1227 #define SQLITE_SHM_SHARED 4
1228 #define SQLITE_SHM_EXCLUSIVE 8
1231 ** CAPI3REF: Maximum xShmLock index
1233 ** The xShmLock method on [sqlite3_io_methods] may use values
1234 ** between 0 and this upper bound as its "offset" argument.
1235 ** The SQLite core will never attempt to acquire or release a
1236 ** lock outside of this range
1238 #define SQLITE_SHM_NLOCK 8
1242 ** CAPI3REF: Initialize The SQLite Library
1244 ** ^The sqlite3_initialize() routine initializes the
1245 ** SQLite library. ^The sqlite3_shutdown() routine
1246 ** deallocates any resources that were allocated by sqlite3_initialize().
1247 ** These routines are designed to aid in process initialization and
1248 ** shutdown on embedded systems. Workstation applications using
1249 ** SQLite normally do not need to invoke either of these routines.
1251 ** A call to sqlite3_initialize() is an "effective" call if it is
1252 ** the first time sqlite3_initialize() is invoked during the lifetime of
1253 ** the process, or if it is the first time sqlite3_initialize() is invoked
1254 ** following a call to sqlite3_shutdown(). ^(Only an effective call
1255 ** of sqlite3_initialize() does any initialization. All other calls
1256 ** are harmless no-ops.)^
1258 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1259 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1260 ** an effective call to sqlite3_shutdown() does any deinitialization.
1261 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1263 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1264 ** is not. The sqlite3_shutdown() interface must only be called from a
1265 ** single thread. All open [database connections] must be closed and all
1266 ** other SQLite resources must be deallocated prior to invoking
1267 ** sqlite3_shutdown().
1269 ** Among other things, ^sqlite3_initialize() will invoke
1270 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1271 ** will invoke sqlite3_os_end().
1273 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1274 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1275 ** the library (perhaps it is unable to allocate a needed resource such
1276 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1278 ** ^The sqlite3_initialize() routine is called internally by many other
1279 ** SQLite interfaces so that an application usually does not need to
1280 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1281 ** calls sqlite3_initialize() so the SQLite library will be automatically
1282 ** initialized when [sqlite3_open()] is called if it has not be initialized
1283 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1284 ** compile-time option, then the automatic calls to sqlite3_initialize()
1285 ** are omitted and the application must call sqlite3_initialize() directly
1286 ** prior to using any other SQLite interface. For maximum portability,
1287 ** it is recommended that applications always invoke sqlite3_initialize()
1288 ** directly prior to using any other SQLite interface. Future releases
1289 ** of SQLite may require this. In other words, the behavior exhibited
1290 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1291 ** default behavior in some future release of SQLite.
1293 ** The sqlite3_os_init() routine does operating-system specific
1294 ** initialization of the SQLite library. The sqlite3_os_end()
1295 ** routine undoes the effect of sqlite3_os_init(). Typical tasks
1296 ** performed by these routines include allocation or deallocation
1297 ** of static resources, initialization of global variables,
1298 ** setting up a default [sqlite3_vfs] module, or setting up
1299 ** a default configuration using [sqlite3_config()].
1301 ** The application should never invoke either sqlite3_os_init()
1302 ** or sqlite3_os_end() directly. The application should only invoke
1303 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1304 ** interface is called automatically by sqlite3_initialize() and
1305 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1306 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1307 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1308 ** When [custom builds | built for other platforms]
1309 ** (using the [SQLITE_OS_OTHER=1] compile-time
1310 ** option) the application must supply a suitable implementation for
1311 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1312 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1313 ** must return [SQLITE_OK] on success and some other [error code] upon
1314 ** failure.
1316 int sqlite3_initialize(void);
1317 int sqlite3_shutdown(void);
1318 int sqlite3_os_init(void);
1319 int sqlite3_os_end(void);
1322 ** CAPI3REF: Configuring The SQLite Library
1324 ** The sqlite3_config() interface is used to make global configuration
1325 ** changes to SQLite in order to tune SQLite to the specific needs of
1326 ** the application. The default configuration is recommended for most
1327 ** applications and so this routine is usually not necessary. It is
1328 ** provided to support rare applications with unusual needs.
1330 ** The sqlite3_config() interface is not threadsafe. The application
1331 ** must insure that no other SQLite interfaces are invoked by other
1332 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config()
1333 ** may only be invoked prior to library initialization using
1334 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1335 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1336 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1337 ** Note, however, that ^sqlite3_config() can be called as part of the
1338 ** implementation of an application-defined [sqlite3_os_init()].
1340 ** The first argument to sqlite3_config() is an integer
1341 ** [configuration option] that determines
1342 ** what property of SQLite is to be configured. Subsequent arguments
1343 ** vary depending on the [configuration option]
1344 ** in the first argument.
1346 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1347 ** ^If the option is unknown or SQLite is unable to set the option
1348 ** then this routine returns a non-zero [error code].
1350 int sqlite3_config(int, ...);
1353 ** CAPI3REF: Configure database connections
1355 ** The sqlite3_db_config() interface is used to make configuration
1356 ** changes to a [database connection]. The interface is similar to
1357 ** [sqlite3_config()] except that the changes apply to a single
1358 ** [database connection] (specified in the first argument).
1360 ** The second argument to sqlite3_db_config(D,V,...) is the
1361 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1362 ** that indicates what aspect of the [database connection] is being configured.
1363 ** Subsequent arguments vary depending on the configuration verb.
1365 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1366 ** the call is considered successful.
1368 int sqlite3_db_config(sqlite3*, int op, ...);
1371 ** CAPI3REF: Memory Allocation Routines
1373 ** An instance of this object defines the interface between SQLite
1374 ** and low-level memory allocation routines.
1376 ** This object is used in only one place in the SQLite interface.
1377 ** A pointer to an instance of this object is the argument to
1378 ** [sqlite3_config()] when the configuration option is
1379 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1380 ** By creating an instance of this object
1381 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1382 ** during configuration, an application can specify an alternative
1383 ** memory allocation subsystem for SQLite to use for all of its
1384 ** dynamic memory needs.
1386 ** Note that SQLite comes with several [built-in memory allocators]
1387 ** that are perfectly adequate for the overwhelming majority of applications
1388 ** and that this object is only useful to a tiny minority of applications
1389 ** with specialized memory allocation requirements. This object is
1390 ** also used during testing of SQLite in order to specify an alternative
1391 ** memory allocator that simulates memory out-of-memory conditions in
1392 ** order to verify that SQLite recovers gracefully from such
1393 ** conditions.
1395 ** The xMalloc, xRealloc, and xFree methods must work like the
1396 ** malloc(), realloc() and free() functions from the standard C library.
1397 ** ^SQLite guarantees that the second argument to
1398 ** xRealloc is always a value returned by a prior call to xRoundup.
1400 ** xSize should return the allocated size of a memory allocation
1401 ** previously obtained from xMalloc or xRealloc. The allocated size
1402 ** is always at least as big as the requested size but may be larger.
1404 ** The xRoundup method returns what would be the allocated size of
1405 ** a memory allocation given a particular requested size. Most memory
1406 ** allocators round up memory allocations at least to the next multiple
1407 ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1408 ** Every memory allocation request coming in through [sqlite3_malloc()]
1409 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1410 ** that causes the corresponding memory allocation to fail.
1412 ** The xInit method initializes the memory allocator. For example,
1413 ** it might allocate any require mutexes or initialize internal data
1414 ** structures. The xShutdown method is invoked (indirectly) by
1415 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1416 ** by xInit. The pAppData pointer is used as the only parameter to
1417 ** xInit and xShutdown.
1419 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1420 ** the xInit method, so the xInit method need not be threadsafe. The
1421 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1422 ** not need to be threadsafe either. For all other methods, SQLite
1423 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1424 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1425 ** it is by default) and so the methods are automatically serialized.
1426 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1427 ** methods must be threadsafe or else make their own arrangements for
1428 ** serialization.
1430 ** SQLite will never invoke xInit() more than once without an intervening
1431 ** call to xShutdown().
1433 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1434 struct sqlite3_mem_methods {
1435 void *(*xMalloc)(int); /* Memory allocation function */
1436 void (*xFree)(void*); /* Free a prior allocation */
1437 void *(*xRealloc)(void*,int); /* Resize an allocation */
1438 int (*xSize)(void*); /* Return the size of an allocation */
1439 int (*xRoundup)(int); /* Round up request size to allocation size */
1440 int (*xInit)(void*); /* Initialize the memory allocator */
1441 void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1442 void *pAppData; /* Argument to xInit() and xShutdown() */
1446 ** CAPI3REF: Configuration Options
1447 ** KEYWORDS: {configuration option}
1449 ** These constants are the available integer configuration options that
1450 ** can be passed as the first argument to the [sqlite3_config()] interface.
1452 ** New configuration options may be added in future releases of SQLite.
1453 ** Existing configuration options might be discontinued. Applications
1454 ** should check the return code from [sqlite3_config()] to make sure that
1455 ** the call worked. The [sqlite3_config()] interface will return a
1456 ** non-zero [error code] if a discontinued or unsupported configuration option
1457 ** is invoked.
1459 ** <dl>
1460 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1461 ** <dd>There are no arguments to this option. ^This option sets the
1462 ** [threading mode] to Single-thread. In other words, it disables
1463 ** all mutexing and puts SQLite into a mode where it can only be used
1464 ** by a single thread. ^If SQLite is compiled with
1465 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1466 ** it is not possible to change the [threading mode] from its default
1467 ** value of Single-thread and so [sqlite3_config()] will return
1468 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1469 ** configuration option.</dd>
1471 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1472 ** <dd>There are no arguments to this option. ^This option sets the
1473 ** [threading mode] to Multi-thread. In other words, it disables
1474 ** mutexing on [database connection] and [prepared statement] objects.
1475 ** The application is responsible for serializing access to
1476 ** [database connections] and [prepared statements]. But other mutexes
1477 ** are enabled so that SQLite will be safe to use in a multi-threaded
1478 ** environment as long as no two threads attempt to use the same
1479 ** [database connection] at the same time. ^If SQLite is compiled with
1480 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1481 ** it is not possible to set the Multi-thread [threading mode] and
1482 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1483 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1485 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1486 ** <dd>There are no arguments to this option. ^This option sets the
1487 ** [threading mode] to Serialized. In other words, this option enables
1488 ** all mutexes including the recursive
1489 ** mutexes on [database connection] and [prepared statement] objects.
1490 ** In this mode (which is the default when SQLite is compiled with
1491 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1492 ** to [database connections] and [prepared statements] so that the
1493 ** application is free to use the same [database connection] or the
1494 ** same [prepared statement] in different threads at the same time.
1495 ** ^If SQLite is compiled with
1496 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1497 ** it is not possible to set the Serialized [threading mode] and
1498 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1499 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1501 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1502 ** <dd> ^(This option takes a single argument which is a pointer to an
1503 ** instance of the [sqlite3_mem_methods] structure. The argument specifies
1504 ** alternative low-level memory allocation routines to be used in place of
1505 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1506 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1507 ** before the [sqlite3_config()] call returns.</dd>
1509 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1510 ** <dd> ^(This option takes a single argument which is a pointer to an
1511 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods]
1512 ** structure is filled with the currently defined memory allocation routines.)^
1513 ** This option can be used to overload the default memory allocation
1514 ** routines with a wrapper that simulations memory allocation failure or
1515 ** tracks memory usage, for example. </dd>
1517 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1518 ** <dd> ^This option takes single argument of type int, interpreted as a
1519 ** boolean, which enables or disables the collection of memory allocation
1520 ** statistics. ^(When memory allocation statistics are disabled, the
1521 ** following SQLite interfaces become non-operational:
1522 ** <ul>
1523 ** <li> [sqlite3_memory_used()]
1524 ** <li> [sqlite3_memory_highwater()]
1525 ** <li> [sqlite3_soft_heap_limit64()]
1526 ** <li> [sqlite3_status()]
1527 ** </ul>)^
1528 ** ^Memory allocation statistics are enabled by default unless SQLite is
1529 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1530 ** allocation statistics are disabled by default.
1531 ** </dd>
1533 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1534 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1535 ** scratch memory. There are three arguments: A pointer an 8-byte
1536 ** aligned memory buffer from which the scratch allocations will be
1537 ** drawn, the size of each scratch allocation (sz),
1538 ** and the maximum number of scratch allocations (N). The sz
1539 ** argument must be a multiple of 16.
1540 ** The first argument must be a pointer to an 8-byte aligned buffer
1541 ** of at least sz*N bytes of memory.
1542 ** ^SQLite will use no more than two scratch buffers per thread. So
1543 ** N should be set to twice the expected maximum number of threads.
1544 ** ^SQLite will never require a scratch buffer that is more than 6
1545 ** times the database page size. ^If SQLite needs needs additional
1546 ** scratch memory beyond what is provided by this configuration option, then
1547 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
1549 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1550 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1551 ** the database page cache with the default page cache implementation.
1552 ** This configuration should not be used if an application-define page
1553 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option.
1554 ** There are three arguments to this option: A pointer to 8-byte aligned
1555 ** memory, the size of each page buffer (sz), and the number of pages (N).
1556 ** The sz argument should be the size of the largest database page
1557 ** (a power of two between 512 and 32768) plus a little extra for each
1558 ** page header. ^The page header size is 20 to 40 bytes depending on
1559 ** the host architecture. ^It is harmless, apart from the wasted memory,
1560 ** to make sz a little too large. The first
1561 ** argument should point to an allocation of at least sz*N bytes of memory.
1562 ** ^SQLite will use the memory provided by the first argument to satisfy its
1563 ** memory needs for the first N pages that it adds to cache. ^If additional
1564 ** page cache memory is needed beyond what is provided by this option, then
1565 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
1566 ** The pointer in the first argument must
1567 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite
1568 ** will be undefined.</dd>
1570 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1571 ** <dd> ^This option specifies a static memory buffer that SQLite will use
1572 ** for all of its dynamic memory allocation needs beyond those provided
1573 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
1574 ** There are three arguments: An 8-byte aligned pointer to the memory,
1575 ** the number of bytes in the memory buffer, and the minimum allocation size.
1576 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1577 ** to using its default memory allocator (the system malloc() implementation),
1578 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1579 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
1580 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
1581 ** allocator is engaged to handle all of SQLites memory allocation needs.
1582 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1583 ** boundary or subsequent behavior of SQLite will be undefined.
1584 ** The minimum allocation size is capped at 2**12. Reasonable values
1585 ** for the minimum allocation size are 2**5 through 2**8.</dd>
1587 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1588 ** <dd> ^(This option takes a single argument which is a pointer to an
1589 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies
1590 ** alternative low-level mutex routines to be used in place
1591 ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the
1592 ** content of the [sqlite3_mutex_methods] structure before the call to
1593 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1594 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1595 ** the entire mutexing subsystem is omitted from the build and hence calls to
1596 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1597 ** return [SQLITE_ERROR].</dd>
1599 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1600 ** <dd> ^(This option takes a single argument which is a pointer to an
1601 ** instance of the [sqlite3_mutex_methods] structure. The
1602 ** [sqlite3_mutex_methods]
1603 ** structure is filled with the currently defined mutex routines.)^
1604 ** This option can be used to overload the default mutex allocation
1605 ** routines with a wrapper used to track mutex usage for performance
1606 ** profiling or testing, for example. ^If SQLite is compiled with
1607 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1608 ** the entire mutexing subsystem is omitted from the build and hence calls to
1609 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1610 ** return [SQLITE_ERROR].</dd>
1612 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1613 ** <dd> ^(This option takes two arguments that determine the default
1614 ** memory allocation for the lookaside memory allocator on each
1615 ** [database connection]. The first argument is the
1616 ** size of each lookaside buffer slot and the second is the number of
1617 ** slots allocated to each database connection.)^ ^(This option sets the
1618 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1619 ** verb to [sqlite3_db_config()] can be used to change the lookaside
1620 ** configuration on individual connections.)^ </dd>
1622 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1623 ** <dd> ^(This option takes a single argument which is a pointer to
1624 ** an [sqlite3_pcache_methods2] object. This object specifies the interface
1625 ** to a custom page cache implementation.)^ ^SQLite makes a copy of the
1626 ** object and uses it for page cache memory allocations.</dd>
1628 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1629 ** <dd> ^(This option takes a single argument which is a pointer to an
1630 ** [sqlite3_pcache_methods2] object. SQLite copies of the current
1631 ** page cache implementation into that object.)^ </dd>
1633 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1634 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1635 ** global [error log].
1636 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1637 ** function with a call signature of void(*)(void*,int,const char*),
1638 ** and a pointer to void. ^If the function pointer is not NULL, it is
1639 ** invoked by [sqlite3_log()] to process each logging event. ^If the
1640 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1641 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1642 ** passed through as the first parameter to the application-defined logger
1643 ** function whenever that function is invoked. ^The second parameter to
1644 ** the logger function is a copy of the first parameter to the corresponding
1645 ** [sqlite3_log()] call and is intended to be a [result code] or an
1646 ** [extended result code]. ^The third parameter passed to the logger is
1647 ** log message after formatting via [sqlite3_snprintf()].
1648 ** The SQLite logging interface is not reentrant; the logger function
1649 ** supplied by the application must not invoke any SQLite interface.
1650 ** In a multi-threaded application, the application-defined logger
1651 ** function must be threadsafe. </dd>
1653 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1654 ** <dd>^(This option takes a single argument of type int. If non-zero, then
1655 ** URI handling is globally enabled. If the parameter is zero, then URI handling
1656 ** is globally disabled.)^ ^If URI handling is globally enabled, all filenames
1657 ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or
1658 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1659 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1660 ** connection is opened. ^If it is globally disabled, filenames are
1661 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1662 ** database connection is opened. ^(By default, URI handling is globally
1663 ** disabled. The default value may be changed by compiling with the
1664 ** [SQLITE_USE_URI] symbol defined.)^
1666 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1667 ** <dd>^This option takes a single integer argument which is interpreted as
1668 ** a boolean in order to enable or disable the use of covering indices for
1669 ** full table scans in the query optimizer. ^The default setting is determined
1670 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1671 ** if that compile-time option is omitted.
1672 ** The ability to disable the use of covering indices for full table scans
1673 ** is because some incorrectly coded legacy applications might malfunction
1674 ** when the optimization is enabled. Providing the ability to
1675 ** disable the optimization allows the older, buggy application code to work
1676 ** without change even with newer versions of SQLite.
1678 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1679 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1680 ** <dd> These options are obsolete and should not be used by new code.
1681 ** They are retained for backwards compatibility but are now no-ops.
1682 ** </dd>
1684 ** [[SQLITE_CONFIG_SQLLOG]]
1685 ** <dt>SQLITE_CONFIG_SQLLOG
1686 ** <dd>This option is only available if sqlite is compiled with the
1687 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1688 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1689 ** The second should be of type (void*). The callback is invoked by the library
1690 ** in three separate circumstances, identified by the value passed as the
1691 ** fourth parameter. If the fourth parameter is 0, then the database connection
1692 ** passed as the second argument has just been opened. The third argument
1693 ** points to a buffer containing the name of the main database file. If the
1694 ** fourth parameter is 1, then the SQL statement that the third parameter
1695 ** points to has just been executed. Or, if the fourth parameter is 2, then
1696 ** the connection being passed as the second parameter is being closed. The
1697 ** third parameter is passed NULL In this case. An example of using this
1698 ** configuration option can be seen in the "test_sqllog.c" source file in
1699 ** the canonical SQLite source tree.</dd>
1701 ** [[SQLITE_CONFIG_MMAP_SIZE]]
1702 ** <dt>SQLITE_CONFIG_MMAP_SIZE
1703 ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1704 ** that are the default mmap size limit (the default setting for
1705 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1706 ** ^The default setting can be overridden by each database connection using
1707 ** either the [PRAGMA mmap_size] command, or by using the
1708 ** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size
1709 ** cannot be changed at run-time. Nor may the maximum allowed mmap size
1710 ** exceed the compile-time maximum mmap size set by the
1711 ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1712 ** ^If either argument to this option is negative, then that argument is
1713 ** changed to its compile-time default.
1715 ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
1716 ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
1717 ** <dd>^This option is only available if SQLite is compiled for Windows
1718 ** with the [SQLITE_WIN32_MALLOC] pre-processor macro defined.
1719 ** SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1720 ** that specifies the maximum size of the created heap.
1721 ** </dl>
1723 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1724 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1725 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1726 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1727 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1728 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */
1729 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1730 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1731 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1732 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1733 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1734 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1735 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1736 #define SQLITE_CONFIG_PCACHE 14 /* no-op */
1737 #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
1738 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
1739 #define SQLITE_CONFIG_URI 17 /* int */
1740 #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
1741 #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
1742 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
1743 #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
1744 #define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
1745 #define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
1748 ** CAPI3REF: Database Connection Configuration Options
1750 ** These constants are the available integer configuration options that
1751 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1753 ** New configuration options may be added in future releases of SQLite.
1754 ** Existing configuration options might be discontinued. Applications
1755 ** should check the return code from [sqlite3_db_config()] to make sure that
1756 ** the call worked. ^The [sqlite3_db_config()] interface will return a
1757 ** non-zero [error code] if a discontinued or unsupported configuration option
1758 ** is invoked.
1760 ** <dl>
1761 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1762 ** <dd> ^This option takes three additional arguments that determine the
1763 ** [lookaside memory allocator] configuration for the [database connection].
1764 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1765 ** pointer to a memory buffer to use for lookaside memory.
1766 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1767 ** may be NULL in which case SQLite will allocate the
1768 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1769 ** size of each lookaside buffer slot. ^The third argument is the number of
1770 ** slots. The size of the buffer in the first argument must be greater than
1771 ** or equal to the product of the second and third arguments. The buffer
1772 ** must be aligned to an 8-byte boundary. ^If the second argument to
1773 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1774 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
1775 ** configuration for a database connection can only be changed when that
1776 ** connection is not currently using lookaside memory, or in other words
1777 ** when the "current value" returned by
1778 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1779 ** Any attempt to change the lookaside memory configuration when lookaside
1780 ** memory is in use leaves the configuration unchanged and returns
1781 ** [SQLITE_BUSY].)^</dd>
1783 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1784 ** <dd> ^This option is used to enable or disable the enforcement of
1785 ** [foreign key constraints]. There should be two additional arguments.
1786 ** The first argument is an integer which is 0 to disable FK enforcement,
1787 ** positive to enable FK enforcement or negative to leave FK enforcement
1788 ** unchanged. The second parameter is a pointer to an integer into which
1789 ** is written 0 or 1 to indicate whether FK enforcement is off or on
1790 ** following this call. The second parameter may be a NULL pointer, in
1791 ** which case the FK enforcement setting is not reported back. </dd>
1793 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1794 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1795 ** There should be two additional arguments.
1796 ** The first argument is an integer which is 0 to disable triggers,
1797 ** positive to enable triggers or negative to leave the setting unchanged.
1798 ** The second parameter is a pointer to an integer into which
1799 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
1800 ** following this call. The second parameter may be a NULL pointer, in
1801 ** which case the trigger setting is not reported back. </dd>
1803 ** </dl>
1805 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
1806 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
1807 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
1811 ** CAPI3REF: Enable Or Disable Extended Result Codes
1813 ** ^The sqlite3_extended_result_codes() routine enables or disables the
1814 ** [extended result codes] feature of SQLite. ^The extended result
1815 ** codes are disabled by default for historical compatibility.
1817 int sqlite3_extended_result_codes(sqlite3*, int onoff);
1820 ** CAPI3REF: Last Insert Rowid
1822 ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
1823 ** has a unique 64-bit signed
1824 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1825 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1826 ** names are not also used by explicitly declared columns. ^If
1827 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
1828 ** is another alias for the rowid.
1830 ** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the
1831 ** most recent successful [INSERT] into a rowid table or [virtual table]
1832 ** on database connection D.
1833 ** ^Inserts into [WITHOUT ROWID] tables are not recorded.
1834 ** ^If no successful [INSERT]s into rowid tables
1835 ** have ever occurred on the database connection D,
1836 ** then sqlite3_last_insert_rowid(D) returns zero.
1838 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
1839 ** method, then this routine will return the [rowid] of the inserted
1840 ** row as long as the trigger or virtual table method is running.
1841 ** But once the trigger or virtual table method ends, the value returned
1842 ** by this routine reverts to what it was before the trigger or virtual
1843 ** table method began.)^
1845 ** ^An [INSERT] that fails due to a constraint violation is not a
1846 ** successful [INSERT] and does not change the value returned by this
1847 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1848 ** and INSERT OR ABORT make no changes to the return value of this
1849 ** routine when their insertion fails. ^(When INSERT OR REPLACE
1850 ** encounters a constraint violation, it does not fail. The
1851 ** INSERT continues to completion after deleting rows that caused
1852 ** the constraint problem so INSERT OR REPLACE will always change
1853 ** the return value of this interface.)^
1855 ** ^For the purposes of this routine, an [INSERT] is considered to
1856 ** be successful even if it is subsequently rolled back.
1858 ** This function is accessible to SQL statements via the
1859 ** [last_insert_rowid() SQL function].
1861 ** If a separate thread performs a new [INSERT] on the same
1862 ** database connection while the [sqlite3_last_insert_rowid()]
1863 ** function is running and thus changes the last insert [rowid],
1864 ** then the value returned by [sqlite3_last_insert_rowid()] is
1865 ** unpredictable and might not equal either the old or the new
1866 ** last insert [rowid].
1868 sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
1871 ** CAPI3REF: Count The Number Of Rows Modified
1873 ** ^This function returns the number of database rows that were changed
1874 ** or inserted or deleted by the most recently completed SQL statement
1875 ** on the [database connection] specified by the first parameter.
1876 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
1877 ** or [DELETE] statement are counted. Auxiliary changes caused by
1878 ** triggers or [foreign key actions] are not counted.)^ Use the
1879 ** [sqlite3_total_changes()] function to find the total number of changes
1880 ** including changes caused by triggers and foreign key actions.
1882 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
1883 ** are not counted. Only real table changes are counted.
1885 ** ^(A "row change" is a change to a single row of a single table
1886 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that
1887 ** are changed as side effects of [REPLACE] constraint resolution,
1888 ** rollback, ABORT processing, [DROP TABLE], or by any other
1889 ** mechanisms do not count as direct row changes.)^
1891 ** A "trigger context" is a scope of execution that begins and
1892 ** ends with the script of a [CREATE TRIGGER | trigger].
1893 ** Most SQL statements are
1894 ** evaluated outside of any trigger. This is the "top level"
1895 ** trigger context. If a trigger fires from the top level, a
1896 ** new trigger context is entered for the duration of that one
1897 ** trigger. Subtriggers create subcontexts for their duration.
1899 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
1900 ** not create a new trigger context.
1902 ** ^This function returns the number of direct row changes in the
1903 ** most recent INSERT, UPDATE, or DELETE statement within the same
1904 ** trigger context.
1906 ** ^Thus, when called from the top level, this function returns the
1907 ** number of changes in the most recent INSERT, UPDATE, or DELETE
1908 ** that also occurred at the top level. ^(Within the body of a trigger,
1909 ** the sqlite3_changes() interface can be called to find the number of
1910 ** changes in the most recently completed INSERT, UPDATE, or DELETE
1911 ** statement within the body of the same trigger.
1912 ** However, the number returned does not include changes
1913 ** caused by subtriggers since those have their own context.)^
1915 ** See also the [sqlite3_total_changes()] interface, the
1916 ** [count_changes pragma], and the [changes() SQL function].
1918 ** If a separate thread makes changes on the same database connection
1919 ** while [sqlite3_changes()] is running then the value returned
1920 ** is unpredictable and not meaningful.
1922 int sqlite3_changes(sqlite3*);
1925 ** CAPI3REF: Total Number Of Rows Modified
1927 ** ^This function returns the number of row changes caused by [INSERT],
1928 ** [UPDATE] or [DELETE] statements since the [database connection] was opened.
1929 ** ^(The count returned by sqlite3_total_changes() includes all changes
1930 ** from all [CREATE TRIGGER | trigger] contexts and changes made by
1931 ** [foreign key actions]. However,
1932 ** the count does not include changes used to implement [REPLACE] constraints,
1933 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The
1934 ** count does not include rows of views that fire an [INSTEAD OF trigger],
1935 ** though if the INSTEAD OF trigger makes changes of its own, those changes
1936 ** are counted.)^
1937 ** ^The sqlite3_total_changes() function counts the changes as soon as
1938 ** the statement that makes them is completed (when the statement handle
1939 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
1941 ** See also the [sqlite3_changes()] interface, the
1942 ** [count_changes pragma], and the [total_changes() SQL function].
1944 ** If a separate thread makes changes on the same database connection
1945 ** while [sqlite3_total_changes()] is running then the value
1946 ** returned is unpredictable and not meaningful.
1948 int sqlite3_total_changes(sqlite3*);
1951 ** CAPI3REF: Interrupt A Long-Running Query
1953 ** ^This function causes any pending database operation to abort and
1954 ** return at its earliest opportunity. This routine is typically
1955 ** called in response to a user action such as pressing "Cancel"
1956 ** or Ctrl-C where the user wants a long query operation to halt
1957 ** immediately.
1959 ** ^It is safe to call this routine from a thread different from the
1960 ** thread that is currently running the database operation. But it
1961 ** is not safe to call this routine with a [database connection] that
1962 ** is closed or might close before sqlite3_interrupt() returns.
1964 ** ^If an SQL operation is very nearly finished at the time when
1965 ** sqlite3_interrupt() is called, then it might not have an opportunity
1966 ** to be interrupted and might continue to completion.
1968 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
1969 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
1970 ** that is inside an explicit transaction, then the entire transaction
1971 ** will be rolled back automatically.
1973 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
1974 ** SQL statements on [database connection] D complete. ^Any new SQL statements
1975 ** that are started after the sqlite3_interrupt() call and before the
1976 ** running statements reaches zero are interrupted as if they had been
1977 ** running prior to the sqlite3_interrupt() call. ^New SQL statements
1978 ** that are started after the running statement count reaches zero are
1979 ** not effected by the sqlite3_interrupt().
1980 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
1981 ** SQL statements is a no-op and has no effect on SQL statements
1982 ** that are started after the sqlite3_interrupt() call returns.
1984 ** If the database connection closes while [sqlite3_interrupt()]
1985 ** is running then bad things will likely happen.
1987 void sqlite3_interrupt(sqlite3*);
1990 ** CAPI3REF: Determine If An SQL Statement Is Complete
1992 ** These routines are useful during command-line input to determine if the
1993 ** currently entered text seems to form a complete SQL statement or
1994 ** if additional input is needed before sending the text into
1995 ** SQLite for parsing. ^These routines return 1 if the input string
1996 ** appears to be a complete SQL statement. ^A statement is judged to be
1997 ** complete if it ends with a semicolon token and is not a prefix of a
1998 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
1999 ** string literals or quoted identifier names or comments are not
2000 ** independent tokens (they are part of the token in which they are
2001 ** embedded) and thus do not count as a statement terminator. ^Whitespace
2002 ** and comments that follow the final semicolon are ignored.
2004 ** ^These routines return 0 if the statement is incomplete. ^If a
2005 ** memory allocation fails, then SQLITE_NOMEM is returned.
2007 ** ^These routines do not parse the SQL statements thus
2008 ** will not detect syntactically incorrect SQL.
2010 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2011 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2012 ** automatically by sqlite3_complete16(). If that initialization fails,
2013 ** then the return value from sqlite3_complete16() will be non-zero
2014 ** regardless of whether or not the input SQL is complete.)^
2016 ** The input to [sqlite3_complete()] must be a zero-terminated
2017 ** UTF-8 string.
2019 ** The input to [sqlite3_complete16()] must be a zero-terminated
2020 ** UTF-16 string in native byte order.
2022 int sqlite3_complete(const char *sql);
2023 int sqlite3_complete16(const void *sql);
2026 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2028 ** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2029 ** that might be invoked with argument P whenever
2030 ** an attempt is made to access a database table associated with
2031 ** [database connection] D when another thread
2032 ** or process has the table locked.
2033 ** The sqlite3_busy_handler() interface is used to implement
2034 ** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2036 ** ^If the busy callback is NULL, then [SQLITE_BUSY]
2037 ** is returned immediately upon encountering the lock. ^If the busy callback
2038 ** is not NULL, then the callback might be invoked with two arguments.
2040 ** ^The first argument to the busy handler is a copy of the void* pointer which
2041 ** is the third argument to sqlite3_busy_handler(). ^The second argument to
2042 ** the busy handler callback is the number of times that the busy handler has
2043 ** been invoked for the same locking event. ^If the
2044 ** busy callback returns 0, then no additional attempts are made to
2045 ** access the database and [SQLITE_BUSY] is returned
2046 ** to the application.
2047 ** ^If the callback returns non-zero, then another attempt
2048 ** is made to access the database and the cycle repeats.
2050 ** The presence of a busy handler does not guarantee that it will be invoked
2051 ** when there is lock contention. ^If SQLite determines that invoking the busy
2052 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2053 ** to the application instead of invoking the
2054 ** busy handler.
2055 ** Consider a scenario where one process is holding a read lock that
2056 ** it is trying to promote to a reserved lock and
2057 ** a second process is holding a reserved lock that it is trying
2058 ** to promote to an exclusive lock. The first process cannot proceed
2059 ** because it is blocked by the second and the second process cannot
2060 ** proceed because it is blocked by the first. If both processes
2061 ** invoke the busy handlers, neither will make any progress. Therefore,
2062 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2063 ** will induce the first process to release its read lock and allow
2064 ** the second process to proceed.
2066 ** ^The default busy callback is NULL.
2068 ** ^(There can only be a single busy handler defined for each
2069 ** [database connection]. Setting a new busy handler clears any
2070 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
2071 ** or evaluating [PRAGMA busy_timeout=N] will change the
2072 ** busy handler and thus clear any previously set busy handler.
2074 ** The busy callback should not take any actions which modify the
2075 ** database connection that invoked the busy handler. In other words,
2076 ** the busy handler is not reentrant. Any such actions
2077 ** result in undefined behavior.
2079 ** A busy handler must not close the database connection
2080 ** or [prepared statement] that invoked the busy handler.
2082 int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
2085 ** CAPI3REF: Set A Busy Timeout
2087 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2088 ** for a specified amount of time when a table is locked. ^The handler
2089 ** will sleep multiple times until at least "ms" milliseconds of sleeping
2090 ** have accumulated. ^After at least "ms" milliseconds of sleeping,
2091 ** the handler returns 0 which causes [sqlite3_step()] to return
2092 ** [SQLITE_BUSY].
2094 ** ^Calling this routine with an argument less than or equal to zero
2095 ** turns off all busy handlers.
2097 ** ^(There can only be a single busy handler for a particular
2098 ** [database connection] at any given moment. If another busy handler
2099 ** was defined (using [sqlite3_busy_handler()]) prior to calling
2100 ** this routine, that other busy handler is cleared.)^
2102 ** See also: [PRAGMA busy_timeout]
2104 int sqlite3_busy_timeout(sqlite3*, int ms);
2107 ** CAPI3REF: Convenience Routines For Running Queries
2109 ** This is a legacy interface that is preserved for backwards compatibility.
2110 ** Use of this interface is not recommended.
2112 ** Definition: A <b>result table</b> is memory data structure created by the
2113 ** [sqlite3_get_table()] interface. A result table records the
2114 ** complete query results from one or more queries.
2116 ** The table conceptually has a number of rows and columns. But
2117 ** these numbers are not part of the result table itself. These
2118 ** numbers are obtained separately. Let N be the number of rows
2119 ** and M be the number of columns.
2121 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2122 ** There are (N+1)*M elements in the array. The first M pointers point
2123 ** to zero-terminated strings that contain the names of the columns.
2124 ** The remaining entries all point to query results. NULL values result
2125 ** in NULL pointers. All other values are in their UTF-8 zero-terminated
2126 ** string representation as returned by [sqlite3_column_text()].
2128 ** A result table might consist of one or more memory allocations.
2129 ** It is not safe to pass a result table directly to [sqlite3_free()].
2130 ** A result table should be deallocated using [sqlite3_free_table()].
2132 ** ^(As an example of the result table format, suppose a query result
2133 ** is as follows:
2135 ** <blockquote><pre>
2136 ** Name | Age
2137 ** -----------------------
2138 ** Alice | 43
2139 ** Bob | 28
2140 ** Cindy | 21
2141 ** </pre></blockquote>
2143 ** There are two column (M==2) and three rows (N==3). Thus the
2144 ** result table has 8 entries. Suppose the result table is stored
2145 ** in an array names azResult. Then azResult holds this content:
2147 ** <blockquote><pre>
2148 ** azResult&#91;0] = "Name";
2149 ** azResult&#91;1] = "Age";
2150 ** azResult&#91;2] = "Alice";
2151 ** azResult&#91;3] = "43";
2152 ** azResult&#91;4] = "Bob";
2153 ** azResult&#91;5] = "28";
2154 ** azResult&#91;6] = "Cindy";
2155 ** azResult&#91;7] = "21";
2156 ** </pre></blockquote>)^
2158 ** ^The sqlite3_get_table() function evaluates one or more
2159 ** semicolon-separated SQL statements in the zero-terminated UTF-8
2160 ** string of its 2nd parameter and returns a result table to the
2161 ** pointer given in its 3rd parameter.
2163 ** After the application has finished with the result from sqlite3_get_table(),
2164 ** it must pass the result table pointer to sqlite3_free_table() in order to
2165 ** release the memory that was malloced. Because of the way the
2166 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2167 ** function must not try to call [sqlite3_free()] directly. Only
2168 ** [sqlite3_free_table()] is able to release the memory properly and safely.
2170 ** The sqlite3_get_table() interface is implemented as a wrapper around
2171 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
2172 ** to any internal data structures of SQLite. It uses only the public
2173 ** interface defined here. As a consequence, errors that occur in the
2174 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2175 ** reflected in subsequent calls to [sqlite3_errcode()] or
2176 ** [sqlite3_errmsg()].
2178 int sqlite3_get_table(
2179 sqlite3 *db, /* An open database */
2180 const char *zSql, /* SQL to be evaluated */
2181 char ***pazResult, /* Results of the query */
2182 int *pnRow, /* Number of result rows written here */
2183 int *pnColumn, /* Number of result columns written here */
2184 char **pzErrmsg /* Error msg written here */
2186 void sqlite3_free_table(char **result);
2189 ** CAPI3REF: Formatted String Printing Functions
2191 ** These routines are work-alikes of the "printf()" family of functions
2192 ** from the standard C library.
2194 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2195 ** results into memory obtained from [sqlite3_malloc()].
2196 ** The strings returned by these two routines should be
2197 ** released by [sqlite3_free()]. ^Both routines return a
2198 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2199 ** memory to hold the resulting string.
2201 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2202 ** the standard C library. The result is written into the
2203 ** buffer supplied as the second parameter whose size is given by
2204 ** the first parameter. Note that the order of the
2205 ** first two parameters is reversed from snprintf().)^ This is an
2206 ** historical accident that cannot be fixed without breaking
2207 ** backwards compatibility. ^(Note also that sqlite3_snprintf()
2208 ** returns a pointer to its buffer instead of the number of
2209 ** characters actually written into the buffer.)^ We admit that
2210 ** the number of characters written would be a more useful return
2211 ** value but we cannot change the implementation of sqlite3_snprintf()
2212 ** now without breaking compatibility.
2214 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2215 ** guarantees that the buffer is always zero-terminated. ^The first
2216 ** parameter "n" is the total size of the buffer, including space for
2217 ** the zero terminator. So the longest string that can be completely
2218 ** written will be n-1 characters.
2220 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2222 ** These routines all implement some additional formatting
2223 ** options that are useful for constructing SQL statements.
2224 ** All of the usual printf() formatting options apply. In addition, there
2225 ** is are "%q", "%Q", and "%z" options.
2227 ** ^(The %q option works like %s in that it substitutes a nul-terminated
2228 ** string from the argument list. But %q also doubles every '\'' character.
2229 ** %q is designed for use inside a string literal.)^ By doubling each '\''
2230 ** character it escapes that character and allows it to be inserted into
2231 ** the string.
2233 ** For example, assume the string variable zText contains text as follows:
2235 ** <blockquote><pre>
2236 ** char *zText = "It's a happy day!";
2237 ** </pre></blockquote>
2239 ** One can use this text in an SQL statement as follows:
2241 ** <blockquote><pre>
2242 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2243 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2244 ** sqlite3_free(zSQL);
2245 ** </pre></blockquote>
2247 ** Because the %q format string is used, the '\'' character in zText
2248 ** is escaped and the SQL generated is as follows:
2250 ** <blockquote><pre>
2251 ** INSERT INTO table1 VALUES('It''s a happy day!')
2252 ** </pre></blockquote>
2254 ** This is correct. Had we used %s instead of %q, the generated SQL
2255 ** would have looked like this:
2257 ** <blockquote><pre>
2258 ** INSERT INTO table1 VALUES('It's a happy day!');
2259 ** </pre></blockquote>
2261 ** This second example is an SQL syntax error. As a general rule you should
2262 ** always use %q instead of %s when inserting text into a string literal.
2264 ** ^(The %Q option works like %q except it also adds single quotes around
2265 ** the outside of the total string. Additionally, if the parameter in the
2266 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2267 ** single quotes).)^ So, for example, one could say:
2269 ** <blockquote><pre>
2270 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2271 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2272 ** sqlite3_free(zSQL);
2273 ** </pre></blockquote>
2275 ** The code above will render a correct SQL statement in the zSQL
2276 ** variable even if the zText variable is a NULL pointer.
2278 ** ^(The "%z" formatting option works like "%s" but with the
2279 ** addition that after the string has been read and copied into
2280 ** the result, [sqlite3_free()] is called on the input string.)^
2282 char *sqlite3_mprintf(const char*,...);
2283 char *sqlite3_vmprintf(const char*, va_list);
2284 char *sqlite3_snprintf(int,char*,const char*, ...);
2285 char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2288 ** CAPI3REF: Memory Allocation Subsystem
2290 ** The SQLite core uses these three routines for all of its own
2291 ** internal memory allocation needs. "Core" in the previous sentence
2292 ** does not include operating-system specific VFS implementation. The
2293 ** Windows VFS uses native malloc() and free() for some operations.
2295 ** ^The sqlite3_malloc() routine returns a pointer to a block
2296 ** of memory at least N bytes in length, where N is the parameter.
2297 ** ^If sqlite3_malloc() is unable to obtain sufficient free
2298 ** memory, it returns a NULL pointer. ^If the parameter N to
2299 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2300 ** a NULL pointer.
2302 ** ^The sqlite3_malloc64(N) routine works just like
2303 ** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2304 ** of a signed 32-bit integer.
2306 ** ^Calling sqlite3_free() with a pointer previously returned
2307 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2308 ** that it might be reused. ^The sqlite3_free() routine is
2309 ** a no-op if is called with a NULL pointer. Passing a NULL pointer
2310 ** to sqlite3_free() is harmless. After being freed, memory
2311 ** should neither be read nor written. Even reading previously freed
2312 ** memory might result in a segmentation fault or other severe error.
2313 ** Memory corruption, a segmentation fault, or other severe error
2314 ** might result if sqlite3_free() is called with a non-NULL pointer that
2315 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2317 ** ^The sqlite3_realloc(X,N) interface attempts to resize a
2318 ** prior memory allocation X to be at least N bytes.
2319 ** ^If the X parameter to sqlite3_realloc(X,N)
2320 ** is a NULL pointer then its behavior is identical to calling
2321 ** sqlite3_malloc(N).
2322 ** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2323 ** negative then the behavior is exactly the same as calling
2324 ** sqlite3_free(X).
2325 ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2326 ** of at least N bytes in size or NULL if insufficient memory is available.
2327 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2328 ** of the prior allocation are copied into the beginning of buffer returned
2329 ** by sqlite3_realloc(X,N) and the prior allocation is freed.
2330 ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2331 ** prior allocation is not freed.
2333 ** ^The sqlite3_realloc64(X,N) interfaces works the same as
2334 ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2335 ** of a 32-bit signed integer.
2337 ** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2338 ** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2339 ** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2340 ** ^The value returned by sqlite3_msize(X) might be larger than the number
2341 ** of bytes requested when X was allocated. ^If X is a NULL pointer then
2342 ** sqlite3_msize(X) returns zero. If X points to something that is not
2343 ** the beginning of memory allocation, or if it points to a formerly
2344 ** valid memory allocation that has now been freed, then the behavior
2345 ** of sqlite3_msize(X) is undefined and possibly harmful.
2347 ** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2348 ** sqlite3_malloc64(), and sqlite3_realloc64()
2349 ** is always aligned to at least an 8 byte boundary, or to a
2350 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2351 ** option is used.
2353 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2354 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2355 ** implementation of these routines to be omitted. That capability
2356 ** is no longer provided. Only built-in memory allocators can be used.
2358 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2359 ** the system malloc() and free() directly when converting
2360 ** filenames between the UTF-8 encoding used by SQLite
2361 ** and whatever filename encoding is used by the particular Windows
2362 ** installation. Memory allocation errors were detected, but
2363 ** they were reported back as [SQLITE_CANTOPEN] or
2364 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2366 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2367 ** must be either NULL or else pointers obtained from a prior
2368 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2369 ** not yet been released.
2371 ** The application must not read or write any part of
2372 ** a block of memory after it has been released using
2373 ** [sqlite3_free()] or [sqlite3_realloc()].
2375 void *sqlite3_malloc(int);
2376 void *sqlite3_malloc64(sqlite3_uint64);
2377 void *sqlite3_realloc(void*, int);
2378 void *sqlite3_realloc64(void*, sqlite3_uint64);
2379 void sqlite3_free(void*);
2380 sqlite3_uint64 sqlite3_msize(void*);
2383 ** CAPI3REF: Memory Allocator Statistics
2385 ** SQLite provides these two interfaces for reporting on the status
2386 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2387 ** routines, which form the built-in memory allocation subsystem.
2389 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2390 ** of memory currently outstanding (malloced but not freed).
2391 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2392 ** value of [sqlite3_memory_used()] since the high-water mark
2393 ** was last reset. ^The values returned by [sqlite3_memory_used()] and
2394 ** [sqlite3_memory_highwater()] include any overhead
2395 ** added by SQLite in its implementation of [sqlite3_malloc()],
2396 ** but not overhead added by the any underlying system library
2397 ** routines that [sqlite3_malloc()] may call.
2399 ** ^The memory high-water mark is reset to the current value of
2400 ** [sqlite3_memory_used()] if and only if the parameter to
2401 ** [sqlite3_memory_highwater()] is true. ^The value returned
2402 ** by [sqlite3_memory_highwater(1)] is the high-water mark
2403 ** prior to the reset.
2405 sqlite3_int64 sqlite3_memory_used(void);
2406 sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2409 ** CAPI3REF: Pseudo-Random Number Generator
2411 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2412 ** select random [ROWID | ROWIDs] when inserting new records into a table that
2413 ** already uses the largest possible [ROWID]. The PRNG is also used for
2414 ** the build-in random() and randomblob() SQL functions. This interface allows
2415 ** applications to access the same PRNG for other purposes.
2417 ** ^A call to this routine stores N bytes of randomness into buffer P.
2418 ** ^If N is less than one, then P can be a NULL pointer.
2420 ** ^If this routine has not been previously called or if the previous
2421 ** call had N less than one, then the PRNG is seeded using randomness
2422 ** obtained from the xRandomness method of the default [sqlite3_vfs] object.
2423 ** ^If the previous call to this routine had an N of 1 or more then
2424 ** the pseudo-randomness is generated
2425 ** internally and without recourse to the [sqlite3_vfs] xRandomness
2426 ** method.
2428 void sqlite3_randomness(int N, void *P);
2431 ** CAPI3REF: Compile-Time Authorization Callbacks
2433 ** ^This routine registers an authorizer callback with a particular
2434 ** [database connection], supplied in the first argument.
2435 ** ^The authorizer callback is invoked as SQL statements are being compiled
2436 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2437 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various
2438 ** points during the compilation process, as logic is being created
2439 ** to perform various actions, the authorizer callback is invoked to
2440 ** see if those actions are allowed. ^The authorizer callback should
2441 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2442 ** specific action but allow the SQL statement to continue to be
2443 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2444 ** rejected with an error. ^If the authorizer callback returns
2445 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2446 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2447 ** the authorizer will fail with an error message.
2449 ** When the callback returns [SQLITE_OK], that means the operation
2450 ** requested is ok. ^When the callback returns [SQLITE_DENY], the
2451 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2452 ** authorizer will fail with an error message explaining that
2453 ** access is denied.
2455 ** ^The first parameter to the authorizer callback is a copy of the third
2456 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2457 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2458 ** the particular action to be authorized. ^The third through sixth parameters
2459 ** to the callback are zero-terminated strings that contain additional
2460 ** details about the action to be authorized.
2462 ** ^If the action code is [SQLITE_READ]
2463 ** and the callback returns [SQLITE_IGNORE] then the
2464 ** [prepared statement] statement is constructed to substitute
2465 ** a NULL value in place of the table column that would have
2466 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2467 ** return can be used to deny an untrusted user access to individual
2468 ** columns of a table.
2469 ** ^If the action code is [SQLITE_DELETE] and the callback returns
2470 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2471 ** [truncate optimization] is disabled and all rows are deleted individually.
2473 ** An authorizer is used when [sqlite3_prepare | preparing]
2474 ** SQL statements from an untrusted source, to ensure that the SQL statements
2475 ** do not try to access data they are not allowed to see, or that they do not
2476 ** try to execute malicious statements that damage the database. For
2477 ** example, an application may allow a user to enter arbitrary
2478 ** SQL queries for evaluation by a database. But the application does
2479 ** not want the user to be able to make arbitrary changes to the
2480 ** database. An authorizer could then be put in place while the
2481 ** user-entered SQL is being [sqlite3_prepare | prepared] that
2482 ** disallows everything except [SELECT] statements.
2484 ** Applications that need to process SQL from untrusted sources
2485 ** might also consider lowering resource limits using [sqlite3_limit()]
2486 ** and limiting database size using the [max_page_count] [PRAGMA]
2487 ** in addition to using an authorizer.
2489 ** ^(Only a single authorizer can be in place on a database connection
2490 ** at a time. Each call to sqlite3_set_authorizer overrides the
2491 ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2492 ** The authorizer is disabled by default.
2494 ** The authorizer callback must not do anything that will modify
2495 ** the database connection that invoked the authorizer callback.
2496 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2497 ** database connections for the meaning of "modify" in this paragraph.
2499 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2500 ** statement might be re-prepared during [sqlite3_step()] due to a
2501 ** schema change. Hence, the application should ensure that the
2502 ** correct authorizer callback remains in place during the [sqlite3_step()].
2504 ** ^Note that the authorizer callback is invoked only during
2505 ** [sqlite3_prepare()] or its variants. Authorization is not
2506 ** performed during statement evaluation in [sqlite3_step()], unless
2507 ** as stated in the previous paragraph, sqlite3_step() invokes
2508 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2510 int sqlite3_set_authorizer(
2511 sqlite3*,
2512 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2513 void *pUserData
2517 ** CAPI3REF: Authorizer Return Codes
2519 ** The [sqlite3_set_authorizer | authorizer callback function] must
2520 ** return either [SQLITE_OK] or one of these two constants in order
2521 ** to signal SQLite whether or not the action is permitted. See the
2522 ** [sqlite3_set_authorizer | authorizer documentation] for additional
2523 ** information.
2525 ** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2526 ** returned from the [sqlite3_vtab_on_conflict()] interface.
2528 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */
2529 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
2532 ** CAPI3REF: Authorizer Action Codes
2534 ** The [sqlite3_set_authorizer()] interface registers a callback function
2535 ** that is invoked to authorize certain SQL statement actions. The
2536 ** second parameter to the callback is an integer code that specifies
2537 ** what action is being authorized. These are the integer action codes that
2538 ** the authorizer callback may be passed.
2540 ** These action code values signify what kind of operation is to be
2541 ** authorized. The 3rd and 4th parameters to the authorization
2542 ** callback function will be parameters or NULL depending on which of these
2543 ** codes is used as the second parameter. ^(The 5th parameter to the
2544 ** authorizer callback is the name of the database ("main", "temp",
2545 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2546 ** is the name of the inner-most trigger or view that is responsible for
2547 ** the access attempt or NULL if this access attempt is directly from
2548 ** top-level SQL code.
2550 /******************************************* 3rd ************ 4th ***********/
2551 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
2552 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
2553 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
2554 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
2555 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
2556 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
2557 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2558 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2559 #define SQLITE_DELETE 9 /* Table Name NULL */
2560 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2561 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2562 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2563 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2564 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2565 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2566 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2567 #define SQLITE_DROP_VIEW 17 /* View Name NULL */
2568 #define SQLITE_INSERT 18 /* Table Name NULL */
2569 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2570 #define SQLITE_READ 20 /* Table Name Column Name */
2571 #define SQLITE_SELECT 21 /* NULL NULL */
2572 #define SQLITE_TRANSACTION 22 /* Operation NULL */
2573 #define SQLITE_UPDATE 23 /* Table Name Column Name */
2574 #define SQLITE_ATTACH 24 /* Filename NULL */
2575 #define SQLITE_DETACH 25 /* Database Name NULL */
2576 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2577 #define SQLITE_REINDEX 27 /* Index Name NULL */
2578 #define SQLITE_ANALYZE 28 /* Table Name NULL */
2579 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2580 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2581 #define SQLITE_FUNCTION 31 /* NULL Function Name */
2582 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2583 #define SQLITE_COPY 0 /* No longer used */
2584 #define SQLITE_RECURSIVE 33 /* NULL NULL */
2587 ** CAPI3REF: Tracing And Profiling Functions
2589 ** These routines register callback functions that can be used for
2590 ** tracing and profiling the execution of SQL statements.
2592 ** ^The callback function registered by sqlite3_trace() is invoked at
2593 ** various times when an SQL statement is being run by [sqlite3_step()].
2594 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2595 ** SQL statement text as the statement first begins executing.
2596 ** ^(Additional sqlite3_trace() callbacks might occur
2597 ** as each triggered subprogram is entered. The callbacks for triggers
2598 ** contain a UTF-8 SQL comment that identifies the trigger.)^
2600 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2601 ** the length of [bound parameter] expansion in the output of sqlite3_trace().
2603 ** ^The callback function registered by sqlite3_profile() is invoked
2604 ** as each SQL statement finishes. ^The profile callback contains
2605 ** the original statement text and an estimate of wall-clock time
2606 ** of how long that statement took to run. ^The profile callback
2607 ** time is in units of nanoseconds, however the current implementation
2608 ** is only capable of millisecond resolution so the six least significant
2609 ** digits in the time are meaningless. Future versions of SQLite
2610 ** might provide greater resolution on the profiler callback. The
2611 ** sqlite3_profile() function is considered experimental and is
2612 ** subject to change in future versions of SQLite.
2614 void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2615 SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
2616 void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2619 ** CAPI3REF: Query Progress Callbacks
2621 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2622 ** function X to be invoked periodically during long running calls to
2623 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2624 ** database connection D. An example use for this
2625 ** interface is to keep a GUI updated during a large query.
2627 ** ^The parameter P is passed through as the only parameter to the
2628 ** callback function X. ^The parameter N is the approximate number of
2629 ** [virtual machine instructions] that are evaluated between successive
2630 ** invocations of the callback X. ^If N is less than one then the progress
2631 ** handler is disabled.
2633 ** ^Only a single progress handler may be defined at one time per
2634 ** [database connection]; setting a new progress handler cancels the
2635 ** old one. ^Setting parameter X to NULL disables the progress handler.
2636 ** ^The progress handler is also disabled by setting N to a value less
2637 ** than 1.
2639 ** ^If the progress callback returns non-zero, the operation is
2640 ** interrupted. This feature can be used to implement a
2641 ** "Cancel" button on a GUI progress dialog box.
2643 ** The progress handler callback must not do anything that will modify
2644 ** the database connection that invoked the progress handler.
2645 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2646 ** database connections for the meaning of "modify" in this paragraph.
2649 void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2652 ** CAPI3REF: Opening A New Database Connection
2654 ** ^These routines open an SQLite database file as specified by the
2655 ** filename argument. ^The filename argument is interpreted as UTF-8 for
2656 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2657 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
2658 ** returned in *ppDb, even if an error occurs. The only exception is that
2659 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2660 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2661 ** object.)^ ^(If the database is opened (and/or created) successfully, then
2662 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
2663 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2664 ** an English language description of the error following a failure of any
2665 ** of the sqlite3_open() routines.
2667 ** ^The default encoding will be UTF-8 for databases created using
2668 ** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases
2669 ** created using sqlite3_open16() will be UTF-16 in the native byte order.
2671 ** Whether or not an error occurs when it is opened, resources
2672 ** associated with the [database connection] handle should be released by
2673 ** passing it to [sqlite3_close()] when it is no longer required.
2675 ** The sqlite3_open_v2() interface works like sqlite3_open()
2676 ** except that it accepts two additional parameters for additional control
2677 ** over the new database connection. ^(The flags parameter to
2678 ** sqlite3_open_v2() can take one of
2679 ** the following three values, optionally combined with the
2680 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2681 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
2683 ** <dl>
2684 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2685 ** <dd>The database is opened in read-only mode. If the database does not
2686 ** already exist, an error is returned.</dd>)^
2688 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2689 ** <dd>The database is opened for reading and writing if possible, or reading
2690 ** only if the file is write protected by the operating system. In either
2691 ** case the database must already exist, otherwise an error is returned.</dd>)^
2693 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2694 ** <dd>The database is opened for reading and writing, and is created if
2695 ** it does not already exist. This is the behavior that is always used for
2696 ** sqlite3_open() and sqlite3_open16().</dd>)^
2697 ** </dl>
2699 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
2700 ** combinations shown above optionally combined with other
2701 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
2702 ** then the behavior is undefined.
2704 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2705 ** opens in the multi-thread [threading mode] as long as the single-thread
2706 ** mode has not been set at compile-time or start-time. ^If the
2707 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2708 ** in the serialized [threading mode] unless single-thread was
2709 ** previously selected at compile-time or start-time.
2710 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2711 ** eligible to use [shared cache mode], regardless of whether or not shared
2712 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
2713 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2714 ** participate in [shared cache mode] even if it is enabled.
2716 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
2717 ** [sqlite3_vfs] object that defines the operating system interface that
2718 ** the new database connection should use. ^If the fourth parameter is
2719 ** a NULL pointer then the default [sqlite3_vfs] object is used.
2721 ** ^If the filename is ":memory:", then a private, temporary in-memory database
2722 ** is created for the connection. ^This in-memory database will vanish when
2723 ** the database connection is closed. Future versions of SQLite might
2724 ** make use of additional special filenames that begin with the ":" character.
2725 ** It is recommended that when a database filename actually does begin with
2726 ** a ":" character you should prefix the filename with a pathname such as
2727 ** "./" to avoid ambiguity.
2729 ** ^If the filename is an empty string, then a private, temporary
2730 ** on-disk database will be created. ^This private database will be
2731 ** automatically deleted as soon as the database connection is closed.
2733 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
2735 ** ^If [URI filename] interpretation is enabled, and the filename argument
2736 ** begins with "file:", then the filename is interpreted as a URI. ^URI
2737 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
2738 ** set in the fourth argument to sqlite3_open_v2(), or if it has
2739 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
2740 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
2741 ** As of SQLite version 3.7.7, URI filename interpretation is turned off
2742 ** by default, but future releases of SQLite might enable URI filename
2743 ** interpretation by default. See "[URI filenames]" for additional
2744 ** information.
2746 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
2747 ** authority, then it must be either an empty string or the string
2748 ** "localhost". ^If the authority is not an empty string or "localhost", an
2749 ** error is returned to the caller. ^The fragment component of a URI, if
2750 ** present, is ignored.
2752 ** ^SQLite uses the path component of the URI as the name of the disk file
2753 ** which contains the database. ^If the path begins with a '/' character,
2754 ** then it is interpreted as an absolute path. ^If the path does not begin
2755 ** with a '/' (meaning that the authority section is omitted from the URI)
2756 ** then the path is interpreted as a relative path.
2757 ** ^(On windows, the first component of an absolute path
2758 ** is a drive specification (e.g. "C:").)^
2760 ** [[core URI query parameters]]
2761 ** The query component of a URI may contain parameters that are interpreted
2762 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
2763 ** SQLite and its built-in [VFSes] interpret the
2764 ** following query parameters:
2766 ** <ul>
2767 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
2768 ** a VFS object that provides the operating system interface that should
2769 ** be used to access the database file on disk. ^If this option is set to
2770 ** an empty string the default VFS object is used. ^Specifying an unknown
2771 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
2772 ** present, then the VFS specified by the option takes precedence over
2773 ** the value passed as the fourth parameter to sqlite3_open_v2().
2775 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
2776 ** "rwc", or "memory". Attempting to set it to any other value is
2777 ** an error)^.
2778 ** ^If "ro" is specified, then the database is opened for read-only
2779 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
2780 ** third argument to sqlite3_open_v2(). ^If the mode option is set to
2781 ** "rw", then the database is opened for read-write (but not create)
2782 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
2783 ** been set. ^Value "rwc" is equivalent to setting both
2784 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
2785 ** set to "memory" then a pure [in-memory database] that never reads
2786 ** or writes from disk is used. ^It is an error to specify a value for
2787 ** the mode parameter that is less restrictive than that specified by
2788 ** the flags passed in the third parameter to sqlite3_open_v2().
2790 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
2791 ** "private". ^Setting it to "shared" is equivalent to setting the
2792 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
2793 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
2794 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
2795 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
2796 ** a URI filename, its value overrides any behavior requested by setting
2797 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
2799 ** <li> <b>psow</b>: ^The psow parameter indicates whether or not the
2800 ** [powersafe overwrite] property does or does not apply to the
2801 ** storage media on which the database file resides.
2803 ** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
2804 ** which if set disables file locking in rollback journal modes. This
2805 ** is useful for accessing a database on a filesystem that does not
2806 ** support locking. Caution: Database corruption might result if two
2807 ** or more processes write to the same database and any one of those
2808 ** processes uses nolock=1.
2810 ** <li> <b>immutable</b>: ^The immutable parameter is a boolean query
2811 ** parameter that indicates that the database file is stored on
2812 ** read-only media. ^When immutable is set, SQLite assumes that the
2813 ** database file cannot be changed, even by a process with higher
2814 ** privilege, and so the database is opened read-only and all locking
2815 ** and change detection is disabled. Caution: Setting the immutable
2816 ** property on a database file that does in fact change can result
2817 ** in incorrect query results and/or [SQLITE_CORRUPT] errors.
2818 ** See also: [SQLITE_IOCAP_IMMUTABLE].
2820 ** </ul>
2822 ** ^Specifying an unknown parameter in the query component of a URI is not an
2823 ** error. Future versions of SQLite might understand additional query
2824 ** parameters. See "[query parameters with special meaning to SQLite]" for
2825 ** additional information.
2827 ** [[URI filename examples]] <h3>URI filename examples</h3>
2829 ** <table border="1" align=center cellpadding=5>
2830 ** <tr><th> URI filenames <th> Results
2831 ** <tr><td> file:data.db <td>
2832 ** Open the file "data.db" in the current directory.
2833 ** <tr><td> file:/home/fred/data.db<br>
2834 ** file:///home/fred/data.db <br>
2835 ** file://localhost/home/fred/data.db <br> <td>
2836 ** Open the database file "/home/fred/data.db".
2837 ** <tr><td> file://darkstar/home/fred/data.db <td>
2838 ** An error. "darkstar" is not a recognized authority.
2839 ** <tr><td style="white-space:nowrap">
2840 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
2841 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive
2842 ** C:. Note that the %20 escaping in this example is not strictly
2843 ** necessary - space characters can be used literally
2844 ** in URI filenames.
2845 ** <tr><td> file:data.db?mode=ro&cache=private <td>
2846 ** Open file "data.db" in the current directory for read-only access.
2847 ** Regardless of whether or not shared-cache mode is enabled by
2848 ** default, use a private cache.
2849 ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
2850 ** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
2851 ** that uses dot-files in place of posix advisory locking.
2852 ** <tr><td> file:data.db?mode=readonly <td>
2853 ** An error. "readonly" is not a valid option for the "mode" parameter.
2854 ** </table>
2856 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
2857 ** query components of a URI. A hexadecimal escape sequence consists of a
2858 ** percent sign - "%" - followed by exactly two hexadecimal digits
2859 ** specifying an octet value. ^Before the path or query components of a
2860 ** URI filename are interpreted, they are encoded using UTF-8 and all
2861 ** hexadecimal escape sequences replaced by a single byte containing the
2862 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
2863 ** the results are undefined.
2865 ** <b>Note to Windows users:</b> The encoding used for the filename argument
2866 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2867 ** codepage is currently defined. Filenames containing international
2868 ** characters must be converted to UTF-8 prior to passing them into
2869 ** sqlite3_open() or sqlite3_open_v2().
2871 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
2872 ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
2873 ** features that require the use of temporary files may fail.
2875 ** See also: [sqlite3_temp_directory]
2877 int sqlite3_open(
2878 const char *filename, /* Database filename (UTF-8) */
2879 sqlite3 **ppDb /* OUT: SQLite db handle */
2881 int sqlite3_open16(
2882 const void *filename, /* Database filename (UTF-16) */
2883 sqlite3 **ppDb /* OUT: SQLite db handle */
2885 int sqlite3_open_v2(
2886 const char *filename, /* Database filename (UTF-8) */
2887 sqlite3 **ppDb, /* OUT: SQLite db handle */
2888 int flags, /* Flags */
2889 const char *zVfs /* Name of VFS module to use */
2893 ** CAPI3REF: Obtain Values For URI Parameters
2895 ** These are utility routines, useful to VFS implementations, that check
2896 ** to see if a database file was a URI that contained a specific query
2897 ** parameter, and if so obtains the value of that query parameter.
2899 ** If F is the database filename pointer passed into the xOpen() method of
2900 ** a VFS implementation when the flags parameter to xOpen() has one or
2901 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
2902 ** P is the name of the query parameter, then
2903 ** sqlite3_uri_parameter(F,P) returns the value of the P
2904 ** parameter if it exists or a NULL pointer if P does not appear as a
2905 ** query parameter on F. If P is a query parameter of F
2906 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
2907 ** a pointer to an empty string.
2909 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
2910 ** parameter and returns true (1) or false (0) according to the value
2911 ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
2912 ** value of query parameter P is one of "yes", "true", or "on" in any
2913 ** case or if the value begins with a non-zero number. The
2914 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
2915 ** query parameter P is one of "no", "false", or "off" in any case or
2916 ** if the value begins with a numeric zero. If P is not a query
2917 ** parameter on F or if the value of P is does not match any of the
2918 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
2920 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
2921 ** 64-bit signed integer and returns that integer, or D if P does not
2922 ** exist. If the value of P is something other than an integer, then
2923 ** zero is returned.
2925 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
2926 ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
2927 ** is not a database file pathname pointer that SQLite passed into the xOpen
2928 ** VFS method, then the behavior of this routine is undefined and probably
2929 ** undesirable.
2931 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
2932 int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
2933 sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
2937 ** CAPI3REF: Error Codes And Messages
2939 ** ^The sqlite3_errcode() interface returns the numeric [result code] or
2940 ** [extended result code] for the most recent failed sqlite3_* API call
2941 ** associated with a [database connection]. If a prior API call failed
2942 ** but the most recent API call succeeded, the return value from
2943 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode()
2944 ** interface is the same except that it always returns the
2945 ** [extended result code] even when extended result codes are
2946 ** disabled.
2948 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
2949 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
2950 ** ^(Memory to hold the error message string is managed internally.
2951 ** The application does not need to worry about freeing the result.
2952 ** However, the error string might be overwritten or deallocated by
2953 ** subsequent calls to other SQLite interface functions.)^
2955 ** ^The sqlite3_errstr() interface returns the English-language text
2956 ** that describes the [result code], as UTF-8.
2957 ** ^(Memory to hold the error message string is managed internally
2958 ** and must not be freed by the application)^.
2960 ** When the serialized [threading mode] is in use, it might be the
2961 ** case that a second error occurs on a separate thread in between
2962 ** the time of the first error and the call to these interfaces.
2963 ** When that happens, the second error will be reported since these
2964 ** interfaces always report the most recent result. To avoid
2965 ** this, each thread can obtain exclusive use of the [database connection] D
2966 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
2967 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
2968 ** all calls to the interfaces listed here are completed.
2970 ** If an interface fails with SQLITE_MISUSE, that means the interface
2971 ** was invoked incorrectly by the application. In that case, the
2972 ** error code and message may or may not be set.
2974 int sqlite3_errcode(sqlite3 *db);
2975 int sqlite3_extended_errcode(sqlite3 *db);
2976 const char *sqlite3_errmsg(sqlite3*);
2977 const void *sqlite3_errmsg16(sqlite3*);
2978 const char *sqlite3_errstr(int);
2981 ** CAPI3REF: SQL Statement Object
2982 ** KEYWORDS: {prepared statement} {prepared statements}
2984 ** An instance of this object represents a single SQL statement.
2985 ** This object is variously known as a "prepared statement" or a
2986 ** "compiled SQL statement" or simply as a "statement".
2988 ** The life of a statement object goes something like this:
2990 ** <ol>
2991 ** <li> Create the object using [sqlite3_prepare_v2()] or a related
2992 ** function.
2993 ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
2994 ** interfaces.
2995 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
2996 ** <li> Reset the statement using [sqlite3_reset()] then go back
2997 ** to step 2. Do this zero or more times.
2998 ** <li> Destroy the object using [sqlite3_finalize()].
2999 ** </ol>
3001 ** Refer to documentation on individual methods above for additional
3002 ** information.
3004 typedef struct sqlite3_stmt sqlite3_stmt;
3007 ** CAPI3REF: Run-time Limits
3009 ** ^(This interface allows the size of various constructs to be limited
3010 ** on a connection by connection basis. The first parameter is the
3011 ** [database connection] whose limit is to be set or queried. The
3012 ** second parameter is one of the [limit categories] that define a
3013 ** class of constructs to be size limited. The third parameter is the
3014 ** new limit for that construct.)^
3016 ** ^If the new limit is a negative number, the limit is unchanged.
3017 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3018 ** [limits | hard upper bound]
3019 ** set at compile-time by a C preprocessor macro called
3020 ** [limits | SQLITE_MAX_<i>NAME</i>].
3021 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3022 ** ^Attempts to increase a limit above its hard upper bound are
3023 ** silently truncated to the hard upper bound.
3025 ** ^Regardless of whether or not the limit was changed, the
3026 ** [sqlite3_limit()] interface returns the prior value of the limit.
3027 ** ^Hence, to find the current value of a limit without changing it,
3028 ** simply invoke this interface with the third parameter set to -1.
3030 ** Run-time limits are intended for use in applications that manage
3031 ** both their own internal database and also databases that are controlled
3032 ** by untrusted external sources. An example application might be a
3033 ** web browser that has its own databases for storing history and
3034 ** separate databases controlled by JavaScript applications downloaded
3035 ** off the Internet. The internal databases can be given the
3036 ** large, default limits. Databases managed by external sources can
3037 ** be given much smaller limits designed to prevent a denial of service
3038 ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
3039 ** interface to further control untrusted SQL. The size of the database
3040 ** created by an untrusted script can be contained using the
3041 ** [max_page_count] [PRAGMA].
3043 ** New run-time limit categories may be added in future releases.
3045 int sqlite3_limit(sqlite3*, int id, int newVal);
3048 ** CAPI3REF: Run-Time Limit Categories
3049 ** KEYWORDS: {limit category} {*limit categories}
3051 ** These constants define various performance limits
3052 ** that can be lowered at run-time using [sqlite3_limit()].
3053 ** The synopsis of the meanings of the various limits is shown below.
3054 ** Additional information is available at [limits | Limits in SQLite].
3056 ** <dl>
3057 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3058 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3060 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3061 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3063 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3064 ** <dd>The maximum number of columns in a table definition or in the
3065 ** result set of a [SELECT] or the maximum number of columns in an index
3066 ** or in an ORDER BY or GROUP BY clause.</dd>)^
3068 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3069 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3071 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3072 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3074 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3075 ** <dd>The maximum number of instructions in a virtual machine program
3076 ** used to implement an SQL statement. This limit is not currently
3077 ** enforced, though that might be added in some future release of
3078 ** SQLite.</dd>)^
3080 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3081 ** <dd>The maximum number of arguments on a function.</dd>)^
3083 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3084 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3086 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3087 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3088 ** <dd>The maximum length of the pattern argument to the [LIKE] or
3089 ** [GLOB] operators.</dd>)^
3091 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3092 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3093 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3095 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3096 ** <dd>The maximum depth of recursion for triggers.</dd>)^
3098 ** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
3099 ** <dd>The maximum number of auxiliary worker threads that a single
3100 ** [prepared statement] may start.</dd>)^
3101 ** </dl>
3103 #define SQLITE_LIMIT_LENGTH 0
3104 #define SQLITE_LIMIT_SQL_LENGTH 1
3105 #define SQLITE_LIMIT_COLUMN 2
3106 #define SQLITE_LIMIT_EXPR_DEPTH 3
3107 #define SQLITE_LIMIT_COMPOUND_SELECT 4
3108 #define SQLITE_LIMIT_VDBE_OP 5
3109 #define SQLITE_LIMIT_FUNCTION_ARG 6
3110 #define SQLITE_LIMIT_ATTACHED 7
3111 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
3112 #define SQLITE_LIMIT_VARIABLE_NUMBER 9
3113 #define SQLITE_LIMIT_TRIGGER_DEPTH 10
3114 #define SQLITE_LIMIT_WORKER_THREADS 11
3117 ** CAPI3REF: Compiling An SQL Statement
3118 ** KEYWORDS: {SQL statement compiler}
3120 ** To execute an SQL query, it must first be compiled into a byte-code
3121 ** program using one of these routines.
3123 ** The first argument, "db", is a [database connection] obtained from a
3124 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3125 ** [sqlite3_open16()]. The database connection must not have been closed.
3127 ** The second argument, "zSql", is the statement to be compiled, encoded
3128 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
3129 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
3130 ** use UTF-16.
3132 ** ^If the nByte argument is less than zero, then zSql is read up to the
3133 ** first zero terminator. ^If nByte is non-negative, then it is the maximum
3134 ** number of bytes read from zSql. ^When nByte is non-negative, the
3135 ** zSql string ends at either the first '\000' or '\u0000' character or
3136 ** the nByte-th byte, whichever comes first. If the caller knows
3137 ** that the supplied string is nul-terminated, then there is a small
3138 ** performance advantage to be gained by passing an nByte parameter that
3139 ** is equal to the number of bytes in the input string <i>including</i>
3140 ** the nul-terminator bytes as this saves SQLite from having to
3141 ** make a copy of the input string.
3143 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3144 ** past the end of the first SQL statement in zSql. These routines only
3145 ** compile the first statement in zSql, so *pzTail is left pointing to
3146 ** what remains uncompiled.
3148 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3149 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
3150 ** to NULL. ^If the input text contains no SQL (if the input is an empty
3151 ** string or a comment) then *ppStmt is set to NULL.
3152 ** The calling procedure is responsible for deleting the compiled
3153 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
3154 ** ppStmt may not be NULL.
3156 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3157 ** otherwise an [error code] is returned.
3159 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
3160 ** recommended for all new programs. The two older interfaces are retained
3161 ** for backwards compatibility, but their use is discouraged.
3162 ** ^In the "v2" interfaces, the prepared statement
3163 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
3164 ** original SQL text. This causes the [sqlite3_step()] interface to
3165 ** behave differently in three ways:
3167 ** <ol>
3168 ** <li>
3169 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3170 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
3171 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3172 ** retries will occur before sqlite3_step() gives up and returns an error.
3173 ** </li>
3175 ** <li>
3176 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3177 ** [error codes] or [extended error codes]. ^The legacy behavior was that
3178 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3179 ** and the application would have to make a second call to [sqlite3_reset()]
3180 ** in order to find the underlying cause of the problem. With the "v2" prepare
3181 ** interfaces, the underlying reason for the error is returned immediately.
3182 ** </li>
3184 ** <li>
3185 ** ^If the specific value bound to [parameter | host parameter] in the
3186 ** WHERE clause might influence the choice of query plan for a statement,
3187 ** then the statement will be automatically recompiled, as if there had been
3188 ** a schema change, on the first [sqlite3_step()] call following any change
3189 ** to the [sqlite3_bind_text | bindings] of that [parameter].
3190 ** ^The specific value of WHERE-clause [parameter] might influence the
3191 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
3192 ** or [GLOB] operator or if the parameter is compared to an indexed column
3193 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3194 ** </li>
3195 ** </ol>
3197 int sqlite3_prepare(
3198 sqlite3 *db, /* Database handle */
3199 const char *zSql, /* SQL statement, UTF-8 encoded */
3200 int nByte, /* Maximum length of zSql in bytes. */
3201 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3202 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3204 int sqlite3_prepare_v2(
3205 sqlite3 *db, /* Database handle */
3206 const char *zSql, /* SQL statement, UTF-8 encoded */
3207 int nByte, /* Maximum length of zSql in bytes. */
3208 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3209 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3211 int sqlite3_prepare16(
3212 sqlite3 *db, /* Database handle */
3213 const void *zSql, /* SQL statement, UTF-16 encoded */
3214 int nByte, /* Maximum length of zSql in bytes. */
3215 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3216 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3218 int sqlite3_prepare16_v2(
3219 sqlite3 *db, /* Database handle */
3220 const void *zSql, /* SQL statement, UTF-16 encoded */
3221 int nByte, /* Maximum length of zSql in bytes. */
3222 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3223 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3227 ** CAPI3REF: Retrieving Statement SQL
3229 ** ^This interface can be used to retrieve a saved copy of the original
3230 ** SQL text used to create a [prepared statement] if that statement was
3231 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
3233 const char *sqlite3_sql(sqlite3_stmt *pStmt);
3236 ** CAPI3REF: Determine If An SQL Statement Writes The Database
3238 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3239 ** and only if the [prepared statement] X makes no direct changes to
3240 ** the content of the database file.
3242 ** Note that [application-defined SQL functions] or
3243 ** [virtual tables] might change the database indirectly as a side effect.
3244 ** ^(For example, if an application defines a function "eval()" that
3245 ** calls [sqlite3_exec()], then the following SQL statement would
3246 ** change the database file through side-effects:
3248 ** <blockquote><pre>
3249 ** SELECT eval('DELETE FROM t1') FROM t2;
3250 ** </pre></blockquote>
3252 ** But because the [SELECT] statement does not change the database file
3253 ** directly, sqlite3_stmt_readonly() would still return true.)^
3255 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3256 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3257 ** since the statements themselves do not actually modify the database but
3258 ** rather they control the timing of when other statements modify the
3259 ** database. ^The [ATTACH] and [DETACH] statements also cause
3260 ** sqlite3_stmt_readonly() to return true since, while those statements
3261 ** change the configuration of a database connection, they do not make
3262 ** changes to the content of the database files on disk.
3264 int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3267 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3269 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3270 ** [prepared statement] S has been stepped at least once using
3271 ** [sqlite3_step(S)] but has not run to completion and/or has not
3272 ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
3273 ** interface returns false if S is a NULL pointer. If S is not a
3274 ** NULL pointer and is not a pointer to a valid [prepared statement]
3275 ** object, then the behavior is undefined and probably undesirable.
3277 ** This interface can be used in combination [sqlite3_next_stmt()]
3278 ** to locate all prepared statements associated with a database
3279 ** connection that are in need of being reset. This can be used,
3280 ** for example, in diagnostic routines to search for prepared
3281 ** statements that are holding a transaction open.
3283 int sqlite3_stmt_busy(sqlite3_stmt*);
3286 ** CAPI3REF: Dynamically Typed Value Object
3287 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3289 ** SQLite uses the sqlite3_value object to represent all values
3290 ** that can be stored in a database table. SQLite uses dynamic typing
3291 ** for the values it stores. ^Values stored in sqlite3_value objects
3292 ** can be integers, floating point values, strings, BLOBs, or NULL.
3294 ** An sqlite3_value object may be either "protected" or "unprotected".
3295 ** Some interfaces require a protected sqlite3_value. Other interfaces
3296 ** will accept either a protected or an unprotected sqlite3_value.
3297 ** Every interface that accepts sqlite3_value arguments specifies
3298 ** whether or not it requires a protected sqlite3_value.
3300 ** The terms "protected" and "unprotected" refer to whether or not
3301 ** a mutex is held. An internal mutex is held for a protected
3302 ** sqlite3_value object but no mutex is held for an unprotected
3303 ** sqlite3_value object. If SQLite is compiled to be single-threaded
3304 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3305 ** or if SQLite is run in one of reduced mutex modes
3306 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3307 ** then there is no distinction between protected and unprotected
3308 ** sqlite3_value objects and they can be used interchangeably. However,
3309 ** for maximum code portability it is recommended that applications
3310 ** still make the distinction between protected and unprotected
3311 ** sqlite3_value objects even when not strictly required.
3313 ** ^The sqlite3_value objects that are passed as parameters into the
3314 ** implementation of [application-defined SQL functions] are protected.
3315 ** ^The sqlite3_value object returned by
3316 ** [sqlite3_column_value()] is unprotected.
3317 ** Unprotected sqlite3_value objects may only be used with
3318 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
3319 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
3320 ** interfaces require protected sqlite3_value objects.
3322 typedef struct Mem sqlite3_value;
3325 ** CAPI3REF: SQL Function Context Object
3327 ** The context in which an SQL function executes is stored in an
3328 ** sqlite3_context object. ^A pointer to an sqlite3_context object
3329 ** is always first parameter to [application-defined SQL functions].
3330 ** The application-defined SQL function implementation will pass this
3331 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3332 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3333 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3334 ** and/or [sqlite3_set_auxdata()].
3336 typedef struct sqlite3_context sqlite3_context;
3339 ** CAPI3REF: Binding Values To Prepared Statements
3340 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3341 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3343 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3344 ** literals may be replaced by a [parameter] that matches one of following
3345 ** templates:
3347 ** <ul>
3348 ** <li> ?
3349 ** <li> ?NNN
3350 ** <li> :VVV
3351 ** <li> @VVV
3352 ** <li> $VVV
3353 ** </ul>
3355 ** In the templates above, NNN represents an integer literal,
3356 ** and VVV represents an alphanumeric identifier.)^ ^The values of these
3357 ** parameters (also called "host parameter names" or "SQL parameters")
3358 ** can be set using the sqlite3_bind_*() routines defined here.
3360 ** ^The first argument to the sqlite3_bind_*() routines is always
3361 ** a pointer to the [sqlite3_stmt] object returned from
3362 ** [sqlite3_prepare_v2()] or its variants.
3364 ** ^The second argument is the index of the SQL parameter to be set.
3365 ** ^The leftmost SQL parameter has an index of 1. ^When the same named
3366 ** SQL parameter is used more than once, second and subsequent
3367 ** occurrences have the same index as the first occurrence.
3368 ** ^The index for named parameters can be looked up using the
3369 ** [sqlite3_bind_parameter_index()] API if desired. ^The index
3370 ** for "?NNN" parameters is the value of NNN.
3371 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
3372 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3374 ** ^The third argument is the value to bind to the parameter.
3375 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3376 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3377 ** is ignored and the end result is the same as sqlite3_bind_null().
3379 ** ^(In those routines that have a fourth argument, its value is the
3380 ** number of bytes in the parameter. To be clear: the value is the
3381 ** number of <u>bytes</u> in the value, not the number of characters.)^
3382 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3383 ** is negative, then the length of the string is
3384 ** the number of bytes up to the first zero terminator.
3385 ** If the fourth parameter to sqlite3_bind_blob() is negative, then
3386 ** the behavior is undefined.
3387 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3388 ** or sqlite3_bind_text16() or sqlite3_bind_text64() then
3389 ** that parameter must be the byte offset
3390 ** where the NUL terminator would occur assuming the string were NUL
3391 ** terminated. If any NUL characters occur at byte offsets less than
3392 ** the value of the fourth parameter then the resulting string value will
3393 ** contain embedded NULs. The result of expressions involving strings
3394 ** with embedded NULs is undefined.
3396 ** ^The fifth argument to the BLOB and string binding interfaces
3397 ** is a destructor used to dispose of the BLOB or
3398 ** string after SQLite has finished with it. ^The destructor is called
3399 ** to dispose of the BLOB or string even if the call to bind API fails.
3400 ** ^If the fifth argument is
3401 ** the special value [SQLITE_STATIC], then SQLite assumes that the
3402 ** information is in static, unmanaged space and does not need to be freed.
3403 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3404 ** SQLite makes its own private copy of the data immediately, before
3405 ** the sqlite3_bind_*() routine returns.
3407 ** ^The sixth argument to sqlite3_bind_text64() must be one of
3408 ** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
3409 ** to specify the encoding of the text in the third parameter. If
3410 ** the sixth argument to sqlite3_bind_text64() is not one of the
3411 ** allowed values shown above, or if the text encoding is different
3412 ** from the encoding specified by the sixth parameter, then the behavior
3413 ** is undefined.
3415 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3416 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
3417 ** (just an integer to hold its size) while it is being processed.
3418 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
3419 ** content is later written using
3420 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
3421 ** ^A negative value for the zeroblob results in a zero-length BLOB.
3423 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3424 ** for the [prepared statement] or with a prepared statement for which
3425 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3426 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
3427 ** routine is passed a [prepared statement] that has been finalized, the
3428 ** result is undefined and probably harmful.
3430 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3431 ** ^Unbound parameters are interpreted as NULL.
3433 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3434 ** [error code] if anything goes wrong.
3435 ** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
3436 ** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
3437 ** [SQLITE_MAX_LENGTH].
3438 ** ^[SQLITE_RANGE] is returned if the parameter
3439 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
3441 ** See also: [sqlite3_bind_parameter_count()],
3442 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3444 int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3445 int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
3446 void(*)(void*));
3447 int sqlite3_bind_double(sqlite3_stmt*, int, double);
3448 int sqlite3_bind_int(sqlite3_stmt*, int, int);
3449 int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3450 int sqlite3_bind_null(sqlite3_stmt*, int);
3451 int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
3452 int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3453 int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
3454 void(*)(void*), unsigned char encoding);
3455 int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3456 int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3459 ** CAPI3REF: Number Of SQL Parameters
3461 ** ^This routine can be used to find the number of [SQL parameters]
3462 ** in a [prepared statement]. SQL parameters are tokens of the
3463 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3464 ** placeholders for values that are [sqlite3_bind_blob | bound]
3465 ** to the parameters at a later time.
3467 ** ^(This routine actually returns the index of the largest (rightmost)
3468 ** parameter. For all forms except ?NNN, this will correspond to the
3469 ** number of unique parameters. If parameters of the ?NNN form are used,
3470 ** there may be gaps in the list.)^
3472 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3473 ** [sqlite3_bind_parameter_name()], and
3474 ** [sqlite3_bind_parameter_index()].
3476 int sqlite3_bind_parameter_count(sqlite3_stmt*);
3479 ** CAPI3REF: Name Of A Host Parameter
3481 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
3482 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
3483 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3484 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3485 ** respectively.
3486 ** In other words, the initial ":" or "$" or "@" or "?"
3487 ** is included as part of the name.)^
3488 ** ^Parameters of the form "?" without a following integer have no name
3489 ** and are referred to as "nameless" or "anonymous parameters".
3491 ** ^The first host parameter has an index of 1, not 0.
3493 ** ^If the value N is out of range or if the N-th parameter is
3494 ** nameless, then NULL is returned. ^The returned string is
3495 ** always in UTF-8 encoding even if the named parameter was
3496 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
3497 ** [sqlite3_prepare16_v2()].
3499 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3500 ** [sqlite3_bind_parameter_count()], and
3501 ** [sqlite3_bind_parameter_index()].
3503 const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
3506 ** CAPI3REF: Index Of A Parameter With A Given Name
3508 ** ^Return the index of an SQL parameter given its name. ^The
3509 ** index value returned is suitable for use as the second
3510 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
3511 ** is returned if no matching parameter is found. ^The parameter
3512 ** name must be given in UTF-8 even if the original statement
3513 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3515 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3516 ** [sqlite3_bind_parameter_count()], and
3517 ** [sqlite3_bind_parameter_index()].
3519 int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
3522 ** CAPI3REF: Reset All Bindings On A Prepared Statement
3524 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3525 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3526 ** ^Use this routine to reset all host parameters to NULL.
3528 int sqlite3_clear_bindings(sqlite3_stmt*);
3531 ** CAPI3REF: Number Of Columns In A Result Set
3533 ** ^Return the number of columns in the result set returned by the
3534 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3535 ** statement that does not return data (for example an [UPDATE]).
3537 ** See also: [sqlite3_data_count()]
3539 int sqlite3_column_count(sqlite3_stmt *pStmt);
3542 ** CAPI3REF: Column Names In A Result Set
3544 ** ^These routines return the name assigned to a particular column
3545 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
3546 ** interface returns a pointer to a zero-terminated UTF-8 string
3547 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
3548 ** UTF-16 string. ^The first parameter is the [prepared statement]
3549 ** that implements the [SELECT] statement. ^The second parameter is the
3550 ** column number. ^The leftmost column is number 0.
3552 ** ^The returned string pointer is valid until either the [prepared statement]
3553 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3554 ** reprepared by the first call to [sqlite3_step()] for a particular run
3555 ** or until the next call to
3556 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3558 ** ^If sqlite3_malloc() fails during the processing of either routine
3559 ** (for example during a conversion from UTF-8 to UTF-16) then a
3560 ** NULL pointer is returned.
3562 ** ^The name of a result column is the value of the "AS" clause for
3563 ** that column, if there is an AS clause. If there is no AS clause
3564 ** then the name of the column is unspecified and may change from
3565 ** one release of SQLite to the next.
3567 const char *sqlite3_column_name(sqlite3_stmt*, int N);
3568 const void *sqlite3_column_name16(sqlite3_stmt*, int N);
3571 ** CAPI3REF: Source Of Data In A Query Result
3573 ** ^These routines provide a means to determine the database, table, and
3574 ** table column that is the origin of a particular result column in
3575 ** [SELECT] statement.
3576 ** ^The name of the database or table or column can be returned as
3577 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
3578 ** the database name, the _table_ routines return the table name, and
3579 ** the origin_ routines return the column name.
3580 ** ^The returned string is valid until the [prepared statement] is destroyed
3581 ** using [sqlite3_finalize()] or until the statement is automatically
3582 ** reprepared by the first call to [sqlite3_step()] for a particular run
3583 ** or until the same information is requested
3584 ** again in a different encoding.
3586 ** ^The names returned are the original un-aliased names of the
3587 ** database, table, and column.
3589 ** ^The first argument to these interfaces is a [prepared statement].
3590 ** ^These functions return information about the Nth result column returned by
3591 ** the statement, where N is the second function argument.
3592 ** ^The left-most column is column 0 for these routines.
3594 ** ^If the Nth column returned by the statement is an expression or
3595 ** subquery and is not a column value, then all of these functions return
3596 ** NULL. ^These routine might also return NULL if a memory allocation error
3597 ** occurs. ^Otherwise, they return the name of the attached database, table,
3598 ** or column that query result column was extracted from.
3600 ** ^As with all other SQLite APIs, those whose names end with "16" return
3601 ** UTF-16 encoded strings and the other functions return UTF-8.
3603 ** ^These APIs are only available if the library was compiled with the
3604 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3606 ** If two or more threads call one or more of these routines against the same
3607 ** prepared statement and column at the same time then the results are
3608 ** undefined.
3610 ** If two or more threads call one or more
3611 ** [sqlite3_column_database_name | column metadata interfaces]
3612 ** for the same [prepared statement] and result column
3613 ** at the same time then the results are undefined.
3615 const char *sqlite3_column_database_name(sqlite3_stmt*,int);
3616 const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
3617 const char *sqlite3_column_table_name(sqlite3_stmt*,int);
3618 const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
3619 const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
3620 const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
3623 ** CAPI3REF: Declared Datatype Of A Query Result
3625 ** ^(The first parameter is a [prepared statement].
3626 ** If this statement is a [SELECT] statement and the Nth column of the
3627 ** returned result set of that [SELECT] is a table column (not an
3628 ** expression or subquery) then the declared type of the table
3629 ** column is returned.)^ ^If the Nth column of the result set is an
3630 ** expression or subquery, then a NULL pointer is returned.
3631 ** ^The returned string is always UTF-8 encoded.
3633 ** ^(For example, given the database schema:
3635 ** CREATE TABLE t1(c1 VARIANT);
3637 ** and the following statement to be compiled:
3639 ** SELECT c1 + 1, c1 FROM t1;
3641 ** this routine would return the string "VARIANT" for the second result
3642 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
3644 ** ^SQLite uses dynamic run-time typing. ^So just because a column
3645 ** is declared to contain a particular type does not mean that the
3646 ** data stored in that column is of the declared type. SQLite is
3647 ** strongly typed, but the typing is dynamic not static. ^Type
3648 ** is associated with individual values, not with the containers
3649 ** used to hold those values.
3651 const char *sqlite3_column_decltype(sqlite3_stmt*,int);
3652 const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
3655 ** CAPI3REF: Evaluate An SQL Statement
3657 ** After a [prepared statement] has been prepared using either
3658 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3659 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3660 ** must be called one or more times to evaluate the statement.
3662 ** The details of the behavior of the sqlite3_step() interface depend
3663 ** on whether the statement was prepared using the newer "v2" interface
3664 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3665 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
3666 ** new "v2" interface is recommended for new applications but the legacy
3667 ** interface will continue to be supported.
3669 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3670 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3671 ** ^With the "v2" interface, any of the other [result codes] or
3672 ** [extended result codes] might be returned as well.
3674 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3675 ** database locks it needs to do its job. ^If the statement is a [COMMIT]
3676 ** or occurs outside of an explicit transaction, then you can retry the
3677 ** statement. If the statement is not a [COMMIT] and occurs within an
3678 ** explicit transaction then you should rollback the transaction before
3679 ** continuing.
3681 ** ^[SQLITE_DONE] means that the statement has finished executing
3682 ** successfully. sqlite3_step() should not be called again on this virtual
3683 ** machine without first calling [sqlite3_reset()] to reset the virtual
3684 ** machine back to its initial state.
3686 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3687 ** is returned each time a new row of data is ready for processing by the
3688 ** caller. The values may be accessed using the [column access functions].
3689 ** sqlite3_step() is called again to retrieve the next row of data.
3691 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3692 ** violation) has occurred. sqlite3_step() should not be called again on
3693 ** the VM. More information may be found by calling [sqlite3_errmsg()].
3694 ** ^With the legacy interface, a more specific error code (for example,
3695 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3696 ** can be obtained by calling [sqlite3_reset()] on the
3697 ** [prepared statement]. ^In the "v2" interface,
3698 ** the more specific error code is returned directly by sqlite3_step().
3700 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3701 ** Perhaps it was called on a [prepared statement] that has
3702 ** already been [sqlite3_finalize | finalized] or on one that had
3703 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
3704 ** be the case that the same database connection is being used by two or
3705 ** more threads at the same moment in time.
3707 ** For all versions of SQLite up to and including 3.6.23.1, a call to
3708 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
3709 ** other than [SQLITE_ROW] before any subsequent invocation of
3710 ** sqlite3_step(). Failure to reset the prepared statement using
3711 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3712 ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began
3713 ** calling [sqlite3_reset()] automatically in this circumstance rather
3714 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
3715 ** break because any application that ever receives an SQLITE_MISUSE error
3716 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
3717 ** can be used to restore the legacy behavior.
3719 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3720 ** API always returns a generic error code, [SQLITE_ERROR], following any
3721 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
3722 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3723 ** specific [error codes] that better describes the error.
3724 ** We admit that this is a goofy design. The problem has been fixed
3725 ** with the "v2" interface. If you prepare all of your SQL statements
3726 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3727 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3728 ** then the more specific [error codes] are returned directly
3729 ** by sqlite3_step(). The use of the "v2" interface is recommended.
3731 int sqlite3_step(sqlite3_stmt*);
3734 ** CAPI3REF: Number of columns in a result set
3736 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
3737 ** current row of the result set of [prepared statement] P.
3738 ** ^If prepared statement P does not have results ready to return
3739 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3740 ** interfaces) then sqlite3_data_count(P) returns 0.
3741 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3742 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
3743 ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
3744 ** will return non-zero if previous call to [sqlite3_step](P) returned
3745 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
3746 ** where it always returns zero since each step of that multi-step
3747 ** pragma returns 0 columns of data.
3749 ** See also: [sqlite3_column_count()]
3751 int sqlite3_data_count(sqlite3_stmt *pStmt);
3754 ** CAPI3REF: Fundamental Datatypes
3755 ** KEYWORDS: SQLITE_TEXT
3757 ** ^(Every value in SQLite has one of five fundamental datatypes:
3759 ** <ul>
3760 ** <li> 64-bit signed integer
3761 ** <li> 64-bit IEEE floating point number
3762 ** <li> string
3763 ** <li> BLOB
3764 ** <li> NULL
3765 ** </ul>)^
3767 ** These constants are codes for each of those types.
3769 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3770 ** for a completely different meaning. Software that links against both
3771 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3772 ** SQLITE_TEXT.
3774 #define SQLITE_INTEGER 1
3775 #define SQLITE_FLOAT 2
3776 #define SQLITE_BLOB 4
3777 #define SQLITE_NULL 5
3778 #ifdef SQLITE_TEXT
3779 # undef SQLITE_TEXT
3780 #else
3781 # define SQLITE_TEXT 3
3782 #endif
3783 #define SQLITE3_TEXT 3
3786 ** CAPI3REF: Result Values From A Query
3787 ** KEYWORDS: {column access functions}
3789 ** These routines form the "result set" interface.
3791 ** ^These routines return information about a single column of the current
3792 ** result row of a query. ^In every case the first argument is a pointer
3793 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3794 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3795 ** and the second argument is the index of the column for which information
3796 ** should be returned. ^The leftmost column of the result set has the index 0.
3797 ** ^The number of columns in the result can be determined using
3798 ** [sqlite3_column_count()].
3800 ** If the SQL statement does not currently point to a valid row, or if the
3801 ** column index is out of range, the result is undefined.
3802 ** These routines may only be called when the most recent call to
3803 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3804 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3805 ** If any of these routines are called after [sqlite3_reset()] or
3806 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3807 ** something other than [SQLITE_ROW], the results are undefined.
3808 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3809 ** are called from a different thread while any of these routines
3810 ** are pending, then the results are undefined.
3812 ** ^The sqlite3_column_type() routine returns the
3813 ** [SQLITE_INTEGER | datatype code] for the initial data type
3814 ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
3815 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
3816 ** returned by sqlite3_column_type() is only meaningful if no type
3817 ** conversions have occurred as described below. After a type conversion,
3818 ** the value returned by sqlite3_column_type() is undefined. Future
3819 ** versions of SQLite may change the behavior of sqlite3_column_type()
3820 ** following a type conversion.
3822 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3823 ** routine returns the number of bytes in that BLOB or string.
3824 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3825 ** the string to UTF-8 and then returns the number of bytes.
3826 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
3827 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3828 ** the number of bytes in that string.
3829 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3831 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3832 ** routine returns the number of bytes in that BLOB or string.
3833 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3834 ** the string to UTF-16 and then returns the number of bytes.
3835 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3836 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3837 ** the number of bytes in that string.
3838 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3840 ** ^The values returned by [sqlite3_column_bytes()] and
3841 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3842 ** of the string. ^For clarity: the values returned by
3843 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3844 ** bytes in the string, not the number of characters.
3846 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3847 ** even empty strings, are always zero-terminated. ^The return
3848 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3850 ** ^The object returned by [sqlite3_column_value()] is an
3851 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object
3852 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
3853 ** If the [unprotected sqlite3_value] object returned by
3854 ** [sqlite3_column_value()] is used in any other way, including calls
3855 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3856 ** or [sqlite3_value_bytes()], then the behavior is undefined.
3858 ** These routines attempt to convert the value where appropriate. ^For
3859 ** example, if the internal representation is FLOAT and a text result
3860 ** is requested, [sqlite3_snprintf()] is used internally to perform the
3861 ** conversion automatically. ^(The following table details the conversions
3862 ** that are applied:
3864 ** <blockquote>
3865 ** <table border="1">
3866 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
3868 ** <tr><td> NULL <td> INTEGER <td> Result is 0
3869 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
3870 ** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer
3871 ** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer
3872 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
3873 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
3874 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
3875 ** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER
3876 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
3877 ** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB
3878 ** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER
3879 ** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL
3880 ** <tr><td> TEXT <td> BLOB <td> No change
3881 ** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER
3882 ** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL
3883 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
3884 ** </table>
3885 ** </blockquote>)^
3887 ** The table above makes reference to standard C library functions atoi()
3888 ** and atof(). SQLite does not really use these functions. It has its
3889 ** own equivalent internal routines. The atoi() and atof() names are
3890 ** used in the table for brevity and because they are familiar to most
3891 ** C programmers.
3893 ** Note that when type conversions occur, pointers returned by prior
3894 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
3895 ** sqlite3_column_text16() may be invalidated.
3896 ** Type conversions and pointer invalidations might occur
3897 ** in the following cases:
3899 ** <ul>
3900 ** <li> The initial content is a BLOB and sqlite3_column_text() or
3901 ** sqlite3_column_text16() is called. A zero-terminator might
3902 ** need to be added to the string.</li>
3903 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
3904 ** sqlite3_column_text16() is called. The content must be converted
3905 ** to UTF-16.</li>
3906 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
3907 ** sqlite3_column_text() is called. The content must be converted
3908 ** to UTF-8.</li>
3909 ** </ul>
3911 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
3912 ** not invalidate a prior pointer, though of course the content of the buffer
3913 ** that the prior pointer references will have been modified. Other kinds
3914 ** of conversion are done in place when it is possible, but sometimes they
3915 ** are not possible and in those cases prior pointers are invalidated.
3917 ** The safest and easiest to remember policy is to invoke these routines
3918 ** in one of the following ways:
3920 ** <ul>
3921 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
3922 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
3923 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
3924 ** </ul>
3926 ** In other words, you should call sqlite3_column_text(),
3927 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
3928 ** into the desired format, then invoke sqlite3_column_bytes() or
3929 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
3930 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
3931 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
3932 ** with calls to sqlite3_column_bytes().
3934 ** ^The pointers returned are valid until a type conversion occurs as
3935 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
3936 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
3937 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned
3938 ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
3939 ** [sqlite3_free()].
3941 ** ^(If a memory allocation error occurs during the evaluation of any
3942 ** of these routines, a default value is returned. The default value
3943 ** is either the integer 0, the floating point number 0.0, or a NULL
3944 ** pointer. Subsequent calls to [sqlite3_errcode()] will return
3945 ** [SQLITE_NOMEM].)^
3947 const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
3948 int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
3949 int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
3950 double sqlite3_column_double(sqlite3_stmt*, int iCol);
3951 int sqlite3_column_int(sqlite3_stmt*, int iCol);
3952 sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
3953 const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
3954 const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
3955 int sqlite3_column_type(sqlite3_stmt*, int iCol);
3956 sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
3959 ** CAPI3REF: Destroy A Prepared Statement Object
3961 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
3962 ** ^If the most recent evaluation of the statement encountered no errors
3963 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
3964 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
3965 ** sqlite3_finalize(S) returns the appropriate [error code] or
3966 ** [extended error code].
3968 ** ^The sqlite3_finalize(S) routine can be called at any point during
3969 ** the life cycle of [prepared statement] S:
3970 ** before statement S is ever evaluated, after
3971 ** one or more calls to [sqlite3_reset()], or after any call
3972 ** to [sqlite3_step()] regardless of whether or not the statement has
3973 ** completed execution.
3975 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
3977 ** The application must finalize every [prepared statement] in order to avoid
3978 ** resource leaks. It is a grievous error for the application to try to use
3979 ** a prepared statement after it has been finalized. Any use of a prepared
3980 ** statement after it has been finalized can result in undefined and
3981 ** undesirable behavior such as segfaults and heap corruption.
3983 int sqlite3_finalize(sqlite3_stmt *pStmt);
3986 ** CAPI3REF: Reset A Prepared Statement Object
3988 ** The sqlite3_reset() function is called to reset a [prepared statement]
3989 ** object back to its initial state, ready to be re-executed.
3990 ** ^Any SQL statement variables that had values bound to them using
3991 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
3992 ** Use [sqlite3_clear_bindings()] to reset the bindings.
3994 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
3995 ** back to the beginning of its program.
3997 ** ^If the most recent call to [sqlite3_step(S)] for the
3998 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
3999 ** or if [sqlite3_step(S)] has never before been called on S,
4000 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
4002 ** ^If the most recent call to [sqlite3_step(S)] for the
4003 ** [prepared statement] S indicated an error, then
4004 ** [sqlite3_reset(S)] returns an appropriate [error code].
4006 ** ^The [sqlite3_reset(S)] interface does not change the values
4007 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4009 int sqlite3_reset(sqlite3_stmt *pStmt);
4012 ** CAPI3REF: Create Or Redefine SQL Functions
4013 ** KEYWORDS: {function creation routines}
4014 ** KEYWORDS: {application-defined SQL function}
4015 ** KEYWORDS: {application-defined SQL functions}
4017 ** ^These functions (collectively known as "function creation routines")
4018 ** are used to add SQL functions or aggregates or to redefine the behavior
4019 ** of existing SQL functions or aggregates. The only differences between
4020 ** these routines are the text encoding expected for
4021 ** the second parameter (the name of the function being created)
4022 ** and the presence or absence of a destructor callback for
4023 ** the application data pointer.
4025 ** ^The first parameter is the [database connection] to which the SQL
4026 ** function is to be added. ^If an application uses more than one database
4027 ** connection then application-defined SQL functions must be added
4028 ** to each database connection separately.
4030 ** ^The second parameter is the name of the SQL function to be created or
4031 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
4032 ** representation, exclusive of the zero-terminator. ^Note that the name
4033 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4034 ** ^Any attempt to create a function with a longer name
4035 ** will result in [SQLITE_MISUSE] being returned.
4037 ** ^The third parameter (nArg)
4038 ** is the number of arguments that the SQL function or
4039 ** aggregate takes. ^If this parameter is -1, then the SQL function or
4040 ** aggregate may take any number of arguments between 0 and the limit
4041 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
4042 ** parameter is less than -1 or greater than 127 then the behavior is
4043 ** undefined.
4045 ** ^The fourth parameter, eTextRep, specifies what
4046 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4047 ** its parameters. The application should set this parameter to
4048 ** [SQLITE_UTF16LE] if the function implementation invokes
4049 ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4050 ** implementation invokes [sqlite3_value_text16be()] on an input, or
4051 ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4052 ** otherwise. ^The same SQL function may be registered multiple times using
4053 ** different preferred text encodings, with different implementations for
4054 ** each encoding.
4055 ** ^When multiple implementations of the same function are available, SQLite
4056 ** will pick the one that involves the least amount of data conversion.
4058 ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4059 ** to signal that the function will always return the same result given
4060 ** the same inputs within a single SQL statement. Most SQL functions are
4061 ** deterministic. The built-in [random()] SQL function is an example of a
4062 ** function that is not deterministic. The SQLite query planner is able to
4063 ** perform additional optimizations on deterministic functions, so use
4064 ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4066 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
4067 ** function can gain access to this pointer using [sqlite3_user_data()].)^
4069 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
4070 ** pointers to C-language functions that implement the SQL function or
4071 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4072 ** callback only; NULL pointers must be passed as the xStep and xFinal
4073 ** parameters. ^An aggregate SQL function requires an implementation of xStep
4074 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4075 ** SQL function or aggregate, pass NULL pointers for all three function
4076 ** callbacks.
4078 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
4079 ** then it is destructor for the application data pointer.
4080 ** The destructor is invoked when the function is deleted, either by being
4081 ** overloaded or when the database connection closes.)^
4082 ** ^The destructor is also invoked if the call to
4083 ** sqlite3_create_function_v2() fails.
4084 ** ^When the destructor callback of the tenth parameter is invoked, it
4085 ** is passed a single argument which is a copy of the application data
4086 ** pointer which was the fifth parameter to sqlite3_create_function_v2().
4088 ** ^It is permitted to register multiple implementations of the same
4089 ** functions with the same name but with either differing numbers of
4090 ** arguments or differing preferred text encodings. ^SQLite will use
4091 ** the implementation that most closely matches the way in which the
4092 ** SQL function is used. ^A function implementation with a non-negative
4093 ** nArg parameter is a better match than a function implementation with
4094 ** a negative nArg. ^A function where the preferred text encoding
4095 ** matches the database encoding is a better
4096 ** match than a function where the encoding is different.
4097 ** ^A function where the encoding difference is between UTF16le and UTF16be
4098 ** is a closer match than a function where the encoding difference is
4099 ** between UTF8 and UTF16.
4101 ** ^Built-in functions may be overloaded by new application-defined functions.
4103 ** ^An application-defined function is permitted to call other
4104 ** SQLite interfaces. However, such calls must not
4105 ** close the database connection nor finalize or reset the prepared
4106 ** statement in which the function is running.
4108 int sqlite3_create_function(
4109 sqlite3 *db,
4110 const char *zFunctionName,
4111 int nArg,
4112 int eTextRep,
4113 void *pApp,
4114 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4115 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4116 void (*xFinal)(sqlite3_context*)
4118 int sqlite3_create_function16(
4119 sqlite3 *db,
4120 const void *zFunctionName,
4121 int nArg,
4122 int eTextRep,
4123 void *pApp,
4124 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4125 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4126 void (*xFinal)(sqlite3_context*)
4128 int sqlite3_create_function_v2(
4129 sqlite3 *db,
4130 const char *zFunctionName,
4131 int nArg,
4132 int eTextRep,
4133 void *pApp,
4134 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4135 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4136 void (*xFinal)(sqlite3_context*),
4137 void(*xDestroy)(void*)
4141 ** CAPI3REF: Text Encodings
4143 ** These constant define integer codes that represent the various
4144 ** text encodings supported by SQLite.
4146 #define SQLITE_UTF8 1
4147 #define SQLITE_UTF16LE 2
4148 #define SQLITE_UTF16BE 3
4149 #define SQLITE_UTF16 4 /* Use native byte order */
4150 #define SQLITE_ANY 5 /* Deprecated */
4151 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
4154 ** CAPI3REF: Function Flags
4156 ** These constants may be ORed together with the
4157 ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4158 ** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4159 ** [sqlite3_create_function_v2()].
4161 #define SQLITE_DETERMINISTIC 0x800
4164 ** CAPI3REF: Deprecated Functions
4165 ** DEPRECATED
4167 ** These functions are [deprecated]. In order to maintain
4168 ** backwards compatibility with older code, these functions continue
4169 ** to be supported. However, new applications should avoid
4170 ** the use of these functions. To help encourage people to avoid
4171 ** using these functions, we are not going to tell you what they do.
4173 #ifndef SQLITE_OMIT_DEPRECATED
4174 SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
4175 SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
4176 SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4177 SQLITE_DEPRECATED int sqlite3_global_recover(void);
4178 SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
4179 SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4180 void*,sqlite3_int64);
4181 #endif
4184 ** CAPI3REF: Obtaining SQL Function Parameter Values
4186 ** The C-language implementation of SQL functions and aggregates uses
4187 ** this set of interface routines to access the parameter values on
4188 ** the function or aggregate.
4190 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
4191 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
4192 ** define callbacks that implement the SQL functions and aggregates.
4193 ** The 3rd parameter to these callbacks is an array of pointers to
4194 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
4195 ** each parameter to the SQL function. These routines are used to
4196 ** extract values from the [sqlite3_value] objects.
4198 ** These routines work only with [protected sqlite3_value] objects.
4199 ** Any attempt to use these routines on an [unprotected sqlite3_value]
4200 ** object results in undefined behavior.
4202 ** ^These routines work just like the corresponding [column access functions]
4203 ** except that these routines take a single [protected sqlite3_value] object
4204 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4206 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4207 ** in the native byte-order of the host machine. ^The
4208 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4209 ** extract UTF-16 strings as big-endian and little-endian respectively.
4211 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
4212 ** numeric affinity to the value. This means that an attempt is
4213 ** made to convert the value to an integer or floating point. If
4214 ** such a conversion is possible without loss of information (in other
4215 ** words, if the value is a string that looks like a number)
4216 ** then the conversion is performed. Otherwise no conversion occurs.
4217 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4219 ** Please pay particular attention to the fact that the pointer returned
4220 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4221 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4222 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4223 ** or [sqlite3_value_text16()].
4225 ** These routines must be called from the same thread as
4226 ** the SQL function that supplied the [sqlite3_value*] parameters.
4228 const void *sqlite3_value_blob(sqlite3_value*);
4229 int sqlite3_value_bytes(sqlite3_value*);
4230 int sqlite3_value_bytes16(sqlite3_value*);
4231 double sqlite3_value_double(sqlite3_value*);
4232 int sqlite3_value_int(sqlite3_value*);
4233 sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
4234 const unsigned char *sqlite3_value_text(sqlite3_value*);
4235 const void *sqlite3_value_text16(sqlite3_value*);
4236 const void *sqlite3_value_text16le(sqlite3_value*);
4237 const void *sqlite3_value_text16be(sqlite3_value*);
4238 int sqlite3_value_type(sqlite3_value*);
4239 int sqlite3_value_numeric_type(sqlite3_value*);
4242 ** CAPI3REF: Obtain Aggregate Function Context
4244 ** Implementations of aggregate SQL functions use this
4245 ** routine to allocate memory for storing their state.
4247 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4248 ** for a particular aggregate function, SQLite
4249 ** allocates N of memory, zeroes out that memory, and returns a pointer
4250 ** to the new memory. ^On second and subsequent calls to
4251 ** sqlite3_aggregate_context() for the same aggregate function instance,
4252 ** the same buffer is returned. Sqlite3_aggregate_context() is normally
4253 ** called once for each invocation of the xStep callback and then one
4254 ** last time when the xFinal callback is invoked. ^(When no rows match
4255 ** an aggregate query, the xStep() callback of the aggregate function
4256 ** implementation is never called and xFinal() is called exactly once.
4257 ** In those cases, sqlite3_aggregate_context() might be called for the
4258 ** first time from within xFinal().)^
4260 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
4261 ** when first called if N is less than or equal to zero or if a memory
4262 ** allocate error occurs.
4264 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4265 ** determined by the N parameter on first successful call. Changing the
4266 ** value of N in subsequent call to sqlite3_aggregate_context() within
4267 ** the same aggregate function instance will not resize the memory
4268 ** allocation.)^ Within the xFinal callback, it is customary to set
4269 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
4270 ** pointless memory allocations occur.
4272 ** ^SQLite automatically frees the memory allocated by
4273 ** sqlite3_aggregate_context() when the aggregate query concludes.
4275 ** The first parameter must be a copy of the
4276 ** [sqlite3_context | SQL function context] that is the first parameter
4277 ** to the xStep or xFinal callback routine that implements the aggregate
4278 ** function.
4280 ** This routine must be called from the same thread in which
4281 ** the aggregate SQL function is running.
4283 void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4286 ** CAPI3REF: User Data For Functions
4288 ** ^The sqlite3_user_data() interface returns a copy of
4289 ** the pointer that was the pUserData parameter (the 5th parameter)
4290 ** of the [sqlite3_create_function()]
4291 ** and [sqlite3_create_function16()] routines that originally
4292 ** registered the application defined function.
4294 ** This routine must be called from the same thread in which
4295 ** the application-defined function is running.
4297 void *sqlite3_user_data(sqlite3_context*);
4300 ** CAPI3REF: Database Connection For Functions
4302 ** ^The sqlite3_context_db_handle() interface returns a copy of
4303 ** the pointer to the [database connection] (the 1st parameter)
4304 ** of the [sqlite3_create_function()]
4305 ** and [sqlite3_create_function16()] routines that originally
4306 ** registered the application defined function.
4308 sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
4311 ** CAPI3REF: Function Auxiliary Data
4313 ** These functions may be used by (non-aggregate) SQL functions to
4314 ** associate metadata with argument values. If the same value is passed to
4315 ** multiple invocations of the same SQL function during query execution, under
4316 ** some circumstances the associated metadata may be preserved. An example
4317 ** of where this might be useful is in a regular-expression matching
4318 ** function. The compiled version of the regular expression can be stored as
4319 ** metadata associated with the pattern string.
4320 ** Then as long as the pattern string remains the same,
4321 ** the compiled regular expression can be reused on multiple
4322 ** invocations of the same function.
4324 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
4325 ** associated by the sqlite3_set_auxdata() function with the Nth argument
4326 ** value to the application-defined function. ^If there is no metadata
4327 ** associated with the function argument, this sqlite3_get_auxdata() interface
4328 ** returns a NULL pointer.
4330 ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
4331 ** argument of the application-defined function. ^Subsequent
4332 ** calls to sqlite3_get_auxdata(C,N) return P from the most recent
4333 ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
4334 ** NULL if the metadata has been discarded.
4335 ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
4336 ** SQLite will invoke the destructor function X with parameter P exactly
4337 ** once, when the metadata is discarded.
4338 ** SQLite is free to discard the metadata at any time, including: <ul>
4339 ** <li> when the corresponding function parameter changes, or
4340 ** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
4341 ** SQL statement, or
4342 ** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or
4343 ** <li> during the original sqlite3_set_auxdata() call when a memory
4344 ** allocation error occurs. </ul>)^
4346 ** Note the last bullet in particular. The destructor X in
4347 ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
4348 ** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
4349 ** should be called near the end of the function implementation and the
4350 ** function implementation should not make any use of P after
4351 ** sqlite3_set_auxdata() has been called.
4353 ** ^(In practice, metadata is preserved between function calls for
4354 ** function parameters that are compile-time constants, including literal
4355 ** values and [parameters] and expressions composed from the same.)^
4357 ** These routines must be called from the same thread in which
4358 ** the SQL function is running.
4360 void *sqlite3_get_auxdata(sqlite3_context*, int N);
4361 void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
4365 ** CAPI3REF: Constants Defining Special Destructor Behavior
4367 ** These are special values for the destructor that is passed in as the
4368 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
4369 ** argument is SQLITE_STATIC, it means that the content pointer is constant
4370 ** and will never change. It does not need to be destroyed. ^The
4371 ** SQLITE_TRANSIENT value means that the content will likely change in
4372 ** the near future and that SQLite should make its own private copy of
4373 ** the content before returning.
4375 ** The typedef is necessary to work around problems in certain
4376 ** C++ compilers.
4378 typedef void (*sqlite3_destructor_type)(void*);
4379 #define SQLITE_STATIC ((sqlite3_destructor_type)0)
4380 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
4383 ** CAPI3REF: Setting The Result Of An SQL Function
4385 ** These routines are used by the xFunc or xFinal callbacks that
4386 ** implement SQL functions and aggregates. See
4387 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
4388 ** for additional information.
4390 ** These functions work very much like the [parameter binding] family of
4391 ** functions used to bind values to host parameters in prepared statements.
4392 ** Refer to the [SQL parameter] documentation for additional information.
4394 ** ^The sqlite3_result_blob() interface sets the result from
4395 ** an application-defined function to be the BLOB whose content is pointed
4396 ** to by the second parameter and which is N bytes long where N is the
4397 ** third parameter.
4399 ** ^The sqlite3_result_zeroblob() interfaces set the result of
4400 ** the application-defined function to be a BLOB containing all zero
4401 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
4403 ** ^The sqlite3_result_double() interface sets the result from
4404 ** an application-defined function to be a floating point value specified
4405 ** by its 2nd argument.
4407 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
4408 ** cause the implemented SQL function to throw an exception.
4409 ** ^SQLite uses the string pointed to by the
4410 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
4411 ** as the text of an error message. ^SQLite interprets the error
4412 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
4413 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
4414 ** byte order. ^If the third parameter to sqlite3_result_error()
4415 ** or sqlite3_result_error16() is negative then SQLite takes as the error
4416 ** message all text up through the first zero character.
4417 ** ^If the third parameter to sqlite3_result_error() or
4418 ** sqlite3_result_error16() is non-negative then SQLite takes that many
4419 ** bytes (not characters) from the 2nd parameter as the error message.
4420 ** ^The sqlite3_result_error() and sqlite3_result_error16()
4421 ** routines make a private copy of the error message text before
4422 ** they return. Hence, the calling function can deallocate or
4423 ** modify the text after they return without harm.
4424 ** ^The sqlite3_result_error_code() function changes the error code
4425 ** returned by SQLite as a result of an error in a function. ^By default,
4426 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
4427 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
4429 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
4430 ** error indicating that a string or BLOB is too long to represent.
4432 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
4433 ** error indicating that a memory allocation failed.
4435 ** ^The sqlite3_result_int() interface sets the return value
4436 ** of the application-defined function to be the 32-bit signed integer
4437 ** value given in the 2nd argument.
4438 ** ^The sqlite3_result_int64() interface sets the return value
4439 ** of the application-defined function to be the 64-bit signed integer
4440 ** value given in the 2nd argument.
4442 ** ^The sqlite3_result_null() interface sets the return value
4443 ** of the application-defined function to be NULL.
4445 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
4446 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
4447 ** set the return value of the application-defined function to be
4448 ** a text string which is represented as UTF-8, UTF-16 native byte order,
4449 ** UTF-16 little endian, or UTF-16 big endian, respectively.
4450 ** ^The sqlite3_result_text64() interface sets the return value of an
4451 ** application-defined function to be a text string in an encoding
4452 ** specified by the fifth (and last) parameter, which must be one
4453 ** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
4454 ** ^SQLite takes the text result from the application from
4455 ** the 2nd parameter of the sqlite3_result_text* interfaces.
4456 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4457 ** is negative, then SQLite takes result text from the 2nd parameter
4458 ** through the first zero character.
4459 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4460 ** is non-negative, then as many bytes (not characters) of the text
4461 ** pointed to by the 2nd parameter are taken as the application-defined
4462 ** function result. If the 3rd parameter is non-negative, then it
4463 ** must be the byte offset into the string where the NUL terminator would
4464 ** appear if the string where NUL terminated. If any NUL characters occur
4465 ** in the string at a byte offset that is less than the value of the 3rd
4466 ** parameter, then the resulting string will contain embedded NULs and the
4467 ** result of expressions operating on strings with embedded NULs is undefined.
4468 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4469 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4470 ** function as the destructor on the text or BLOB result when it has
4471 ** finished using that result.
4472 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4473 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4474 ** assumes that the text or BLOB result is in constant space and does not
4475 ** copy the content of the parameter nor call a destructor on the content
4476 ** when it has finished using that result.
4477 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4478 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4479 ** then SQLite makes a copy of the result into space obtained from
4480 ** from [sqlite3_malloc()] before it returns.
4482 ** ^The sqlite3_result_value() interface sets the result of
4483 ** the application-defined function to be a copy the
4484 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
4485 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4486 ** so that the [sqlite3_value] specified in the parameter may change or
4487 ** be deallocated after sqlite3_result_value() returns without harm.
4488 ** ^A [protected sqlite3_value] object may always be used where an
4489 ** [unprotected sqlite3_value] object is required, so either
4490 ** kind of [sqlite3_value] object can be used with this interface.
4492 ** If these routines are called from within the different thread
4493 ** than the one containing the application-defined function that received
4494 ** the [sqlite3_context] pointer, the results are undefined.
4496 void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4497 void sqlite3_result_blob64(sqlite3_context*,const void*,sqlite3_uint64,void(*)(void*));
4498 void sqlite3_result_double(sqlite3_context*, double);
4499 void sqlite3_result_error(sqlite3_context*, const char*, int);
4500 void sqlite3_result_error16(sqlite3_context*, const void*, int);
4501 void sqlite3_result_error_toobig(sqlite3_context*);
4502 void sqlite3_result_error_nomem(sqlite3_context*);
4503 void sqlite3_result_error_code(sqlite3_context*, int);
4504 void sqlite3_result_int(sqlite3_context*, int);
4505 void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4506 void sqlite3_result_null(sqlite3_context*);
4507 void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4508 void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
4509 void(*)(void*), unsigned char encoding);
4510 void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4511 void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4512 void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4513 void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4514 void sqlite3_result_zeroblob(sqlite3_context*, int n);
4517 ** CAPI3REF: Define New Collating Sequences
4519 ** ^These functions add, remove, or modify a [collation] associated
4520 ** with the [database connection] specified as the first argument.
4522 ** ^The name of the collation is a UTF-8 string
4523 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4524 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4525 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4526 ** considered to be the same name.
4528 ** ^(The third argument (eTextRep) must be one of the constants:
4529 ** <ul>
4530 ** <li> [SQLITE_UTF8],
4531 ** <li> [SQLITE_UTF16LE],
4532 ** <li> [SQLITE_UTF16BE],
4533 ** <li> [SQLITE_UTF16], or
4534 ** <li> [SQLITE_UTF16_ALIGNED].
4535 ** </ul>)^
4536 ** ^The eTextRep argument determines the encoding of strings passed
4537 ** to the collating function callback, xCallback.
4538 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4539 ** force strings to be UTF16 with native byte order.
4540 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4541 ** on an even byte address.
4543 ** ^The fourth argument, pArg, is an application data pointer that is passed
4544 ** through as the first argument to the collating function callback.
4546 ** ^The fifth argument, xCallback, is a pointer to the collating function.
4547 ** ^Multiple collating functions can be registered using the same name but
4548 ** with different eTextRep parameters and SQLite will use whichever
4549 ** function requires the least amount of data transformation.
4550 ** ^If the xCallback argument is NULL then the collating function is
4551 ** deleted. ^When all collating functions having the same name are deleted,
4552 ** that collation is no longer usable.
4554 ** ^The collating function callback is invoked with a copy of the pArg
4555 ** application data pointer and with two strings in the encoding specified
4556 ** by the eTextRep argument. The collating function must return an
4557 ** integer that is negative, zero, or positive
4558 ** if the first string is less than, equal to, or greater than the second,
4559 ** respectively. A collating function must always return the same answer
4560 ** given the same inputs. If two or more collating functions are registered
4561 ** to the same collation name (using different eTextRep values) then all
4562 ** must give an equivalent answer when invoked with equivalent strings.
4563 ** The collating function must obey the following properties for all
4564 ** strings A, B, and C:
4566 ** <ol>
4567 ** <li> If A==B then B==A.
4568 ** <li> If A==B and B==C then A==C.
4569 ** <li> If A&lt;B THEN B&gt;A.
4570 ** <li> If A&lt;B and B&lt;C then A&lt;C.
4571 ** </ol>
4573 ** If a collating function fails any of the above constraints and that
4574 ** collating function is registered and used, then the behavior of SQLite
4575 ** is undefined.
4577 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4578 ** with the addition that the xDestroy callback is invoked on pArg when
4579 ** the collating function is deleted.
4580 ** ^Collating functions are deleted when they are overridden by later
4581 ** calls to the collation creation functions or when the
4582 ** [database connection] is closed using [sqlite3_close()].
4584 ** ^The xDestroy callback is <u>not</u> called if the
4585 ** sqlite3_create_collation_v2() function fails. Applications that invoke
4586 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4587 ** check the return code and dispose of the application data pointer
4588 ** themselves rather than expecting SQLite to deal with it for them.
4589 ** This is different from every other SQLite interface. The inconsistency
4590 ** is unfortunate but cannot be changed without breaking backwards
4591 ** compatibility.
4593 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4595 int sqlite3_create_collation(
4596 sqlite3*,
4597 const char *zName,
4598 int eTextRep,
4599 void *pArg,
4600 int(*xCompare)(void*,int,const void*,int,const void*)
4602 int sqlite3_create_collation_v2(
4603 sqlite3*,
4604 const char *zName,
4605 int eTextRep,
4606 void *pArg,
4607 int(*xCompare)(void*,int,const void*,int,const void*),
4608 void(*xDestroy)(void*)
4610 int sqlite3_create_collation16(
4611 sqlite3*,
4612 const void *zName,
4613 int eTextRep,
4614 void *pArg,
4615 int(*xCompare)(void*,int,const void*,int,const void*)
4619 ** CAPI3REF: Collation Needed Callbacks
4621 ** ^To avoid having to register all collation sequences before a database
4622 ** can be used, a single callback function may be registered with the
4623 ** [database connection] to be invoked whenever an undefined collation
4624 ** sequence is required.
4626 ** ^If the function is registered using the sqlite3_collation_needed() API,
4627 ** then it is passed the names of undefined collation sequences as strings
4628 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4629 ** the names are passed as UTF-16 in machine native byte order.
4630 ** ^A call to either function replaces the existing collation-needed callback.
4632 ** ^(When the callback is invoked, the first argument passed is a copy
4633 ** of the second argument to sqlite3_collation_needed() or
4634 ** sqlite3_collation_needed16(). The second argument is the database
4635 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4636 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4637 ** sequence function required. The fourth parameter is the name of the
4638 ** required collation sequence.)^
4640 ** The callback function should register the desired collation using
4641 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4642 ** [sqlite3_create_collation_v2()].
4644 int sqlite3_collation_needed(
4645 sqlite3*,
4646 void*,
4647 void(*)(void*,sqlite3*,int eTextRep,const char*)
4649 int sqlite3_collation_needed16(
4650 sqlite3*,
4651 void*,
4652 void(*)(void*,sqlite3*,int eTextRep,const void*)
4655 #ifdef SQLITE_HAS_CODEC
4657 ** Specify the key for an encrypted database. This routine should be
4658 ** called right after sqlite3_open().
4660 ** The code to implement this API is not available in the public release
4661 ** of SQLite.
4663 int sqlite3_key(
4664 sqlite3 *db, /* Database to be rekeyed */
4665 const void *pKey, int nKey /* The key */
4667 int sqlite3_key_v2(
4668 sqlite3 *db, /* Database to be rekeyed */
4669 const char *zDbName, /* Name of the database */
4670 const void *pKey, int nKey /* The key */
4674 ** Change the key on an open database. If the current database is not
4675 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
4676 ** database is decrypted.
4678 ** The code to implement this API is not available in the public release
4679 ** of SQLite.
4681 int sqlite3_rekey(
4682 sqlite3 *db, /* Database to be rekeyed */
4683 const void *pKey, int nKey /* The new key */
4685 int sqlite3_rekey_v2(
4686 sqlite3 *db, /* Database to be rekeyed */
4687 const char *zDbName, /* Name of the database */
4688 const void *pKey, int nKey /* The new key */
4692 ** Specify the activation key for a SEE database. Unless
4693 ** activated, none of the SEE routines will work.
4695 void sqlite3_activate_see(
4696 const char *zPassPhrase /* Activation phrase */
4698 #endif
4700 #ifdef SQLITE_ENABLE_CEROD
4702 ** Specify the activation key for a CEROD database. Unless
4703 ** activated, none of the CEROD routines will work.
4705 void sqlite3_activate_cerod(
4706 const char *zPassPhrase /* Activation phrase */
4708 #endif
4711 ** CAPI3REF: Suspend Execution For A Short Time
4713 ** The sqlite3_sleep() function causes the current thread to suspend execution
4714 ** for at least a number of milliseconds specified in its parameter.
4716 ** If the operating system does not support sleep requests with
4717 ** millisecond time resolution, then the time will be rounded up to
4718 ** the nearest second. The number of milliseconds of sleep actually
4719 ** requested from the operating system is returned.
4721 ** ^SQLite implements this interface by calling the xSleep()
4722 ** method of the default [sqlite3_vfs] object. If the xSleep() method
4723 ** of the default VFS is not implemented correctly, or not implemented at
4724 ** all, then the behavior of sqlite3_sleep() may deviate from the description
4725 ** in the previous paragraphs.
4727 int sqlite3_sleep(int);
4730 ** CAPI3REF: Name Of The Folder Holding Temporary Files
4732 ** ^(If this global variable is made to point to a string which is
4733 ** the name of a folder (a.k.a. directory), then all temporary files
4734 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4735 ** will be placed in that directory.)^ ^If this variable
4736 ** is a NULL pointer, then SQLite performs a search for an appropriate
4737 ** temporary file directory.
4739 ** Applications are strongly discouraged from using this global variable.
4740 ** It is required to set a temporary folder on Windows Runtime (WinRT).
4741 ** But for all other platforms, it is highly recommended that applications
4742 ** neither read nor write this variable. This global variable is a relic
4743 ** that exists for backwards compatibility of legacy applications and should
4744 ** be avoided in new projects.
4746 ** It is not safe to read or modify this variable in more than one
4747 ** thread at a time. It is not safe to read or modify this variable
4748 ** if a [database connection] is being used at the same time in a separate
4749 ** thread.
4750 ** It is intended that this variable be set once
4751 ** as part of process initialization and before any SQLite interface
4752 ** routines have been called and that this variable remain unchanged
4753 ** thereafter.
4755 ** ^The [temp_store_directory pragma] may modify this variable and cause
4756 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4757 ** the [temp_store_directory pragma] always assumes that any string
4758 ** that this variable points to is held in memory obtained from
4759 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4760 ** using [sqlite3_free].
4761 ** Hence, if this variable is modified directly, either it should be
4762 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4763 ** or else the use of the [temp_store_directory pragma] should be avoided.
4764 ** Except when requested by the [temp_store_directory pragma], SQLite
4765 ** does not free the memory that sqlite3_temp_directory points to. If
4766 ** the application wants that memory to be freed, it must do
4767 ** so itself, taking care to only do so after all [database connection]
4768 ** objects have been destroyed.
4770 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
4771 ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
4772 ** features that require the use of temporary files may fail. Here is an
4773 ** example of how to do this using C++ with the Windows Runtime:
4775 ** <blockquote><pre>
4776 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
4777 ** &nbsp; TemporaryFolder->Path->Data();
4778 ** char zPathBuf&#91;MAX_PATH + 1&#93;;
4779 ** memset(zPathBuf, 0, sizeof(zPathBuf));
4780 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
4781 ** &nbsp; NULL, NULL);
4782 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
4783 ** </pre></blockquote>
4785 SQLITE_EXTERN char *sqlite3_temp_directory;
4788 ** CAPI3REF: Name Of The Folder Holding Database Files
4790 ** ^(If this global variable is made to point to a string which is
4791 ** the name of a folder (a.k.a. directory), then all database files
4792 ** specified with a relative pathname and created or accessed by
4793 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
4794 ** to be relative to that directory.)^ ^If this variable is a NULL
4795 ** pointer, then SQLite assumes that all database files specified
4796 ** with a relative pathname are relative to the current directory
4797 ** for the process. Only the windows VFS makes use of this global
4798 ** variable; it is ignored by the unix VFS.
4800 ** Changing the value of this variable while a database connection is
4801 ** open can result in a corrupt database.
4803 ** It is not safe to read or modify this variable in more than one
4804 ** thread at a time. It is not safe to read or modify this variable
4805 ** if a [database connection] is being used at the same time in a separate
4806 ** thread.
4807 ** It is intended that this variable be set once
4808 ** as part of process initialization and before any SQLite interface
4809 ** routines have been called and that this variable remain unchanged
4810 ** thereafter.
4812 ** ^The [data_store_directory pragma] may modify this variable and cause
4813 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4814 ** the [data_store_directory pragma] always assumes that any string
4815 ** that this variable points to is held in memory obtained from
4816 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4817 ** using [sqlite3_free].
4818 ** Hence, if this variable is modified directly, either it should be
4819 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4820 ** or else the use of the [data_store_directory pragma] should be avoided.
4822 SQLITE_EXTERN char *sqlite3_data_directory;
4825 ** CAPI3REF: Test For Auto-Commit Mode
4826 ** KEYWORDS: {autocommit mode}
4828 ** ^The sqlite3_get_autocommit() interface returns non-zero or
4829 ** zero if the given database connection is or is not in autocommit mode,
4830 ** respectively. ^Autocommit mode is on by default.
4831 ** ^Autocommit mode is disabled by a [BEGIN] statement.
4832 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
4834 ** If certain kinds of errors occur on a statement within a multi-statement
4835 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
4836 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
4837 ** transaction might be rolled back automatically. The only way to
4838 ** find out whether SQLite automatically rolled back the transaction after
4839 ** an error is to use this function.
4841 ** If another thread changes the autocommit status of the database
4842 ** connection while this routine is running, then the return value
4843 ** is undefined.
4845 int sqlite3_get_autocommit(sqlite3*);
4848 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
4850 ** ^The sqlite3_db_handle interface returns the [database connection] handle
4851 ** to which a [prepared statement] belongs. ^The [database connection]
4852 ** returned by sqlite3_db_handle is the same [database connection]
4853 ** that was the first argument
4854 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
4855 ** create the statement in the first place.
4857 sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
4860 ** CAPI3REF: Return The Filename For A Database Connection
4862 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
4863 ** associated with database N of connection D. ^The main database file
4864 ** has the name "main". If there is no attached database N on the database
4865 ** connection D, or if database N is a temporary or in-memory database, then
4866 ** a NULL pointer is returned.
4868 ** ^The filename returned by this function is the output of the
4869 ** xFullPathname method of the [VFS]. ^In other words, the filename
4870 ** will be an absolute pathname, even if the filename used
4871 ** to open the database originally was a URI or relative pathname.
4873 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
4876 ** CAPI3REF: Determine if a database is read-only
4878 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
4879 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
4880 ** the name of a database on connection D.
4882 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
4885 ** CAPI3REF: Find the next prepared statement
4887 ** ^This interface returns a pointer to the next [prepared statement] after
4888 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
4889 ** then this interface returns a pointer to the first prepared statement
4890 ** associated with the database connection pDb. ^If no prepared statement
4891 ** satisfies the conditions of this routine, it returns NULL.
4893 ** The [database connection] pointer D in a call to
4894 ** [sqlite3_next_stmt(D,S)] must refer to an open database
4895 ** connection and in particular must not be a NULL pointer.
4897 sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
4900 ** CAPI3REF: Commit And Rollback Notification Callbacks
4902 ** ^The sqlite3_commit_hook() interface registers a callback
4903 ** function to be invoked whenever a transaction is [COMMIT | committed].
4904 ** ^Any callback set by a previous call to sqlite3_commit_hook()
4905 ** for the same database connection is overridden.
4906 ** ^The sqlite3_rollback_hook() interface registers a callback
4907 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
4908 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
4909 ** for the same database connection is overridden.
4910 ** ^The pArg argument is passed through to the callback.
4911 ** ^If the callback on a commit hook function returns non-zero,
4912 ** then the commit is converted into a rollback.
4914 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
4915 ** return the P argument from the previous call of the same function
4916 ** on the same [database connection] D, or NULL for
4917 ** the first call for each function on D.
4919 ** The commit and rollback hook callbacks are not reentrant.
4920 ** The callback implementation must not do anything that will modify
4921 ** the database connection that invoked the callback. Any actions
4922 ** to modify the database connection must be deferred until after the
4923 ** completion of the [sqlite3_step()] call that triggered the commit
4924 ** or rollback hook in the first place.
4925 ** Note that running any other SQL statements, including SELECT statements,
4926 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
4927 ** the database connections for the meaning of "modify" in this paragraph.
4929 ** ^Registering a NULL function disables the callback.
4931 ** ^When the commit hook callback routine returns zero, the [COMMIT]
4932 ** operation is allowed to continue normally. ^If the commit hook
4933 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
4934 ** ^The rollback hook is invoked on a rollback that results from a commit
4935 ** hook returning non-zero, just as it would be with any other rollback.
4937 ** ^For the purposes of this API, a transaction is said to have been
4938 ** rolled back if an explicit "ROLLBACK" statement is executed, or
4939 ** an error or constraint causes an implicit rollback to occur.
4940 ** ^The rollback callback is not invoked if a transaction is
4941 ** automatically rolled back because the database connection is closed.
4943 ** See also the [sqlite3_update_hook()] interface.
4945 void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
4946 void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
4949 ** CAPI3REF: Data Change Notification Callbacks
4951 ** ^The sqlite3_update_hook() interface registers a callback function
4952 ** with the [database connection] identified by the first argument
4953 ** to be invoked whenever a row is updated, inserted or deleted in
4954 ** a rowid table.
4955 ** ^Any callback set by a previous call to this function
4956 ** for the same database connection is overridden.
4958 ** ^The second argument is a pointer to the function to invoke when a
4959 ** row is updated, inserted or deleted in a rowid table.
4960 ** ^The first argument to the callback is a copy of the third argument
4961 ** to sqlite3_update_hook().
4962 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
4963 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
4964 ** to be invoked.
4965 ** ^The third and fourth arguments to the callback contain pointers to the
4966 ** database and table name containing the affected row.
4967 ** ^The final callback parameter is the [rowid] of the row.
4968 ** ^In the case of an update, this is the [rowid] after the update takes place.
4970 ** ^(The update hook is not invoked when internal system tables are
4971 ** modified (i.e. sqlite_master and sqlite_sequence).)^
4972 ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
4974 ** ^In the current implementation, the update hook
4975 ** is not invoked when duplication rows are deleted because of an
4976 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
4977 ** invoked when rows are deleted using the [truncate optimization].
4978 ** The exceptions defined in this paragraph might change in a future
4979 ** release of SQLite.
4981 ** The update hook implementation must not do anything that will modify
4982 ** the database connection that invoked the update hook. Any actions
4983 ** to modify the database connection must be deferred until after the
4984 ** completion of the [sqlite3_step()] call that triggered the update hook.
4985 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
4986 ** database connections for the meaning of "modify" in this paragraph.
4988 ** ^The sqlite3_update_hook(D,C,P) function
4989 ** returns the P argument from the previous call
4990 ** on the same [database connection] D, or NULL for
4991 ** the first call on D.
4993 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
4994 ** interfaces.
4996 void *sqlite3_update_hook(
4997 sqlite3*,
4998 void(*)(void *,int ,char const *,char const *,sqlite3_int64),
4999 void*
5003 ** CAPI3REF: Enable Or Disable Shared Pager Cache
5005 ** ^(This routine enables or disables the sharing of the database cache
5006 ** and schema data structures between [database connection | connections]
5007 ** to the same database. Sharing is enabled if the argument is true
5008 ** and disabled if the argument is false.)^
5010 ** ^Cache sharing is enabled and disabled for an entire process.
5011 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
5012 ** sharing was enabled or disabled for each thread separately.
5014 ** ^(The cache sharing mode set by this interface effects all subsequent
5015 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
5016 ** Existing database connections continue use the sharing mode
5017 ** that was in effect at the time they were opened.)^
5019 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
5020 ** successfully. An [error code] is returned otherwise.)^
5022 ** ^Shared cache is disabled by default. But this might change in
5023 ** future releases of SQLite. Applications that care about shared
5024 ** cache setting should set it explicitly.
5026 ** This interface is threadsafe on processors where writing a
5027 ** 32-bit integer is atomic.
5029 ** See Also: [SQLite Shared-Cache Mode]
5031 int sqlite3_enable_shared_cache(int);
5034 ** CAPI3REF: Attempt To Free Heap Memory
5036 ** ^The sqlite3_release_memory() interface attempts to free N bytes
5037 ** of heap memory by deallocating non-essential memory allocations
5038 ** held by the database library. Memory used to cache database
5039 ** pages to improve performance is an example of non-essential memory.
5040 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
5041 ** which might be more or less than the amount requested.
5042 ** ^The sqlite3_release_memory() routine is a no-op returning zero
5043 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5045 ** See also: [sqlite3_db_release_memory()]
5047 int sqlite3_release_memory(int);
5050 ** CAPI3REF: Free Memory Used By A Database Connection
5052 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
5053 ** memory as possible from database connection D. Unlike the
5054 ** [sqlite3_release_memory()] interface, this interface is in effect even
5055 ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
5056 ** omitted.
5058 ** See also: [sqlite3_release_memory()]
5060 int sqlite3_db_release_memory(sqlite3*);
5063 ** CAPI3REF: Impose A Limit On Heap Size
5065 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
5066 ** soft limit on the amount of heap memory that may be allocated by SQLite.
5067 ** ^SQLite strives to keep heap memory utilization below the soft heap
5068 ** limit by reducing the number of pages held in the page cache
5069 ** as heap memory usages approaches the limit.
5070 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
5071 ** below the limit, it will exceed the limit rather than generate
5072 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
5073 ** is advisory only.
5075 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
5076 ** the soft heap limit prior to the call, or negative in the case of an
5077 ** error. ^If the argument N is negative
5078 ** then no change is made to the soft heap limit. Hence, the current
5079 ** size of the soft heap limit can be determined by invoking
5080 ** sqlite3_soft_heap_limit64() with a negative argument.
5082 ** ^If the argument N is zero then the soft heap limit is disabled.
5084 ** ^(The soft heap limit is not enforced in the current implementation
5085 ** if one or more of following conditions are true:
5087 ** <ul>
5088 ** <li> The soft heap limit is set to zero.
5089 ** <li> Memory accounting is disabled using a combination of the
5090 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
5091 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
5092 ** <li> An alternative page cache implementation is specified using
5093 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
5094 ** <li> The page cache allocates from its own memory pool supplied
5095 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
5096 ** from the heap.
5097 ** </ul>)^
5099 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
5100 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
5101 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
5102 ** the soft heap limit is enforced on every memory allocation. Without
5103 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
5104 ** when memory is allocated by the page cache. Testing suggests that because
5105 ** the page cache is the predominate memory user in SQLite, most
5106 ** applications will achieve adequate soft heap limit enforcement without
5107 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5109 ** The circumstances under which SQLite will enforce the soft heap limit may
5110 ** changes in future releases of SQLite.
5112 sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
5115 ** CAPI3REF: Deprecated Soft Heap Limit Interface
5116 ** DEPRECATED
5118 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
5119 ** interface. This routine is provided for historical compatibility
5120 ** only. All new applications should use the
5121 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
5123 SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
5127 ** CAPI3REF: Extract Metadata About A Column Of A Table
5129 ** ^This routine returns metadata about a specific column of a specific
5130 ** database table accessible using the [database connection] handle
5131 ** passed as the first function argument.
5133 ** ^The column is identified by the second, third and fourth parameters to
5134 ** this function. ^The second parameter is either the name of the database
5135 ** (i.e. "main", "temp", or an attached database) containing the specified
5136 ** table or NULL. ^If it is NULL, then all attached databases are searched
5137 ** for the table using the same algorithm used by the database engine to
5138 ** resolve unqualified table references.
5140 ** ^The third and fourth parameters to this function are the table and column
5141 ** name of the desired column, respectively. Neither of these parameters
5142 ** may be NULL.
5144 ** ^Metadata is returned by writing to the memory locations passed as the 5th
5145 ** and subsequent parameters to this function. ^Any of these arguments may be
5146 ** NULL, in which case the corresponding element of metadata is omitted.
5148 ** ^(<blockquote>
5149 ** <table border="1">
5150 ** <tr><th> Parameter <th> Output<br>Type <th> Description
5152 ** <tr><td> 5th <td> const char* <td> Data type
5153 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
5154 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
5155 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
5156 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
5157 ** </table>
5158 ** </blockquote>)^
5160 ** ^The memory pointed to by the character pointers returned for the
5161 ** declaration type and collation sequence is valid only until the next
5162 ** call to any SQLite API function.
5164 ** ^If the specified table is actually a view, an [error code] is returned.
5166 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an
5167 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
5168 ** parameters are set for the explicitly declared column. ^(If there is no
5169 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
5170 ** parameters are set as follows:
5172 ** <pre>
5173 ** data type: "INTEGER"
5174 ** collation sequence: "BINARY"
5175 ** not null: 0
5176 ** primary key: 1
5177 ** auto increment: 0
5178 ** </pre>)^
5180 ** ^(This function may load one or more schemas from database files. If an
5181 ** error occurs during this process, or if the requested table or column
5182 ** cannot be found, an [error code] is returned and an error message left
5183 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
5185 ** ^This API is only available if the library was compiled with the
5186 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
5188 int sqlite3_table_column_metadata(
5189 sqlite3 *db, /* Connection handle */
5190 const char *zDbName, /* Database name or NULL */
5191 const char *zTableName, /* Table name */
5192 const char *zColumnName, /* Column name */
5193 char const **pzDataType, /* OUTPUT: Declared data type */
5194 char const **pzCollSeq, /* OUTPUT: Collation sequence name */
5195 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
5196 int *pPrimaryKey, /* OUTPUT: True if column part of PK */
5197 int *pAutoinc /* OUTPUT: True if column is auto-increment */
5201 ** CAPI3REF: Load An Extension
5203 ** ^This interface loads an SQLite extension library from the named file.
5205 ** ^The sqlite3_load_extension() interface attempts to load an
5206 ** [SQLite extension] library contained in the file zFile. If
5207 ** the file cannot be loaded directly, attempts are made to load
5208 ** with various operating-system specific extensions added.
5209 ** So for example, if "samplelib" cannot be loaded, then names like
5210 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
5211 ** be tried also.
5213 ** ^The entry point is zProc.
5214 ** ^(zProc may be 0, in which case SQLite will try to come up with an
5215 ** entry point name on its own. It first tries "sqlite3_extension_init".
5216 ** If that does not work, it constructs a name "sqlite3_X_init" where the
5217 ** X is consists of the lower-case equivalent of all ASCII alphabetic
5218 ** characters in the filename from the last "/" to the first following
5219 ** "." and omitting any initial "lib".)^
5220 ** ^The sqlite3_load_extension() interface returns
5221 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
5222 ** ^If an error occurs and pzErrMsg is not 0, then the
5223 ** [sqlite3_load_extension()] interface shall attempt to
5224 ** fill *pzErrMsg with error message text stored in memory
5225 ** obtained from [sqlite3_malloc()]. The calling function
5226 ** should free this memory by calling [sqlite3_free()].
5228 ** ^Extension loading must be enabled using
5229 ** [sqlite3_enable_load_extension()] prior to calling this API,
5230 ** otherwise an error will be returned.
5232 ** See also the [load_extension() SQL function].
5234 int sqlite3_load_extension(
5235 sqlite3 *db, /* Load the extension into this database connection */
5236 const char *zFile, /* Name of the shared library containing extension */
5237 const char *zProc, /* Entry point. Derived from zFile if 0 */
5238 char **pzErrMsg /* Put error message here if not 0 */
5242 ** CAPI3REF: Enable Or Disable Extension Loading
5244 ** ^So as not to open security holes in older applications that are
5245 ** unprepared to deal with [extension loading], and as a means of disabling
5246 ** [extension loading] while evaluating user-entered SQL, the following API
5247 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5249 ** ^Extension loading is off by default.
5250 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5251 ** to turn extension loading on and call it with onoff==0 to turn
5252 ** it back off again.
5254 int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
5257 ** CAPI3REF: Automatically Load Statically Linked Extensions
5259 ** ^This interface causes the xEntryPoint() function to be invoked for
5260 ** each new [database connection] that is created. The idea here is that
5261 ** xEntryPoint() is the entry point for a statically linked [SQLite extension]
5262 ** that is to be automatically loaded into all new database connections.
5264 ** ^(Even though the function prototype shows that xEntryPoint() takes
5265 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
5266 ** arguments and expects and integer result as if the signature of the
5267 ** entry point where as follows:
5269 ** <blockquote><pre>
5270 ** &nbsp; int xEntryPoint(
5271 ** &nbsp; sqlite3 *db,
5272 ** &nbsp; const char **pzErrMsg,
5273 ** &nbsp; const struct sqlite3_api_routines *pThunk
5274 ** &nbsp; );
5275 ** </pre></blockquote>)^
5277 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
5278 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
5279 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
5280 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
5281 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
5282 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
5283 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
5285 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
5286 ** on the list of automatic extensions is a harmless no-op. ^No entry point
5287 ** will be called more than once for each database connection that is opened.
5289 ** See also: [sqlite3_reset_auto_extension()]
5290 ** and [sqlite3_cancel_auto_extension()]
5292 int sqlite3_auto_extension(void (*xEntryPoint)(void));
5295 ** CAPI3REF: Cancel Automatic Extension Loading
5297 ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
5298 ** initialization routine X that was registered using a prior call to
5299 ** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)]
5300 ** routine returns 1 if initialization routine X was successfully
5301 ** unregistered and it returns 0 if X was not on the list of initialization
5302 ** routines.
5304 int sqlite3_cancel_auto_extension(void (*xEntryPoint)(void));
5307 ** CAPI3REF: Reset Automatic Extension Loading
5309 ** ^This interface disables all automatic extensions previously
5310 ** registered using [sqlite3_auto_extension()].
5312 void sqlite3_reset_auto_extension(void);
5315 ** The interface to the virtual-table mechanism is currently considered
5316 ** to be experimental. The interface might change in incompatible ways.
5317 ** If this is a problem for you, do not use the interface at this time.
5319 ** When the virtual-table mechanism stabilizes, we will declare the
5320 ** interface fixed, support it indefinitely, and remove this comment.
5324 ** Structures used by the virtual table interface
5326 typedef struct sqlite3_vtab sqlite3_vtab;
5327 typedef struct sqlite3_index_info sqlite3_index_info;
5328 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
5329 typedef struct sqlite3_module sqlite3_module;
5332 ** CAPI3REF: Virtual Table Object
5333 ** KEYWORDS: sqlite3_module {virtual table module}
5335 ** This structure, sometimes called a "virtual table module",
5336 ** defines the implementation of a [virtual tables].
5337 ** This structure consists mostly of methods for the module.
5339 ** ^A virtual table module is created by filling in a persistent
5340 ** instance of this structure and passing a pointer to that instance
5341 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
5342 ** ^The registration remains valid until it is replaced by a different
5343 ** module or until the [database connection] closes. The content
5344 ** of this structure must not change while it is registered with
5345 ** any database connection.
5347 struct sqlite3_module {
5348 int iVersion;
5349 int (*xCreate)(sqlite3*, void *pAux,
5350 int argc, const char *const*argv,
5351 sqlite3_vtab **ppVTab, char**);
5352 int (*xConnect)(sqlite3*, void *pAux,
5353 int argc, const char *const*argv,
5354 sqlite3_vtab **ppVTab, char**);
5355 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
5356 int (*xDisconnect)(sqlite3_vtab *pVTab);
5357 int (*xDestroy)(sqlite3_vtab *pVTab);
5358 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
5359 int (*xClose)(sqlite3_vtab_cursor*);
5360 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
5361 int argc, sqlite3_value **argv);
5362 int (*xNext)(sqlite3_vtab_cursor*);
5363 int (*xEof)(sqlite3_vtab_cursor*);
5364 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
5365 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
5366 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
5367 int (*xBegin)(sqlite3_vtab *pVTab);
5368 int (*xSync)(sqlite3_vtab *pVTab);
5369 int (*xCommit)(sqlite3_vtab *pVTab);
5370 int (*xRollback)(sqlite3_vtab *pVTab);
5371 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
5372 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
5373 void **ppArg);
5374 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
5375 /* The methods above are in version 1 of the sqlite_module object. Those
5376 ** below are for version 2 and greater. */
5377 int (*xSavepoint)(sqlite3_vtab *pVTab, int);
5378 int (*xRelease)(sqlite3_vtab *pVTab, int);
5379 int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
5383 ** CAPI3REF: Virtual Table Indexing Information
5384 ** KEYWORDS: sqlite3_index_info
5386 ** The sqlite3_index_info structure and its substructures is used as part
5387 ** of the [virtual table] interface to
5388 ** pass information into and receive the reply from the [xBestIndex]
5389 ** method of a [virtual table module]. The fields under **Inputs** are the
5390 ** inputs to xBestIndex and are read-only. xBestIndex inserts its
5391 ** results into the **Outputs** fields.
5393 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
5395 ** <blockquote>column OP expr</blockquote>
5397 ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^ ^(The particular operator is
5398 ** stored in aConstraint[].op using one of the
5399 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
5400 ** ^(The index of the column is stored in
5401 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
5402 ** expr on the right-hand side can be evaluated (and thus the constraint
5403 ** is usable) and false if it cannot.)^
5405 ** ^The optimizer automatically inverts terms of the form "expr OP column"
5406 ** and makes other simplifications to the WHERE clause in an attempt to
5407 ** get as many WHERE clause terms into the form shown above as possible.
5408 ** ^The aConstraint[] array only reports WHERE clause terms that are
5409 ** relevant to the particular virtual table being queried.
5411 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
5412 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
5414 ** The [xBestIndex] method must fill aConstraintUsage[] with information
5415 ** about what parameters to pass to xFilter. ^If argvIndex>0 then
5416 ** the right-hand side of the corresponding aConstraint[] is evaluated
5417 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
5418 ** is true, then the constraint is assumed to be fully handled by the
5419 ** virtual table and is not checked again by SQLite.)^
5421 ** ^The idxNum and idxPtr values are recorded and passed into the
5422 ** [xFilter] method.
5423 ** ^[sqlite3_free()] is used to free idxPtr if and only if
5424 ** needToFreeIdxPtr is true.
5426 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
5427 ** the correct order to satisfy the ORDER BY clause so that no separate
5428 ** sorting step is required.
5430 ** ^The estimatedCost value is an estimate of the cost of a particular
5431 ** strategy. A cost of N indicates that the cost of the strategy is similar
5432 ** to a linear scan of an SQLite table with N rows. A cost of log(N)
5433 ** indicates that the expense of the operation is similar to that of a
5434 ** binary search on a unique indexed field of an SQLite table with N rows.
5436 ** ^The estimatedRows value is an estimate of the number of rows that
5437 ** will be returned by the strategy.
5439 ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
5440 ** structure for SQLite version 3.8.2. If a virtual table extension is
5441 ** used with an SQLite version earlier than 3.8.2, the results of attempting
5442 ** to read or write the estimatedRows field are undefined (but are likely
5443 ** to included crashing the application). The estimatedRows field should
5444 ** therefore only be used if [sqlite3_libversion_number()] returns a
5445 ** value greater than or equal to 3008002.
5447 struct sqlite3_index_info {
5448 /* Inputs */
5449 int nConstraint; /* Number of entries in aConstraint */
5450 struct sqlite3_index_constraint {
5451 int iColumn; /* Column on left-hand side of constraint */
5452 unsigned char op; /* Constraint operator */
5453 unsigned char usable; /* True if this constraint is usable */
5454 int iTermOffset; /* Used internally - xBestIndex should ignore */
5455 } *aConstraint; /* Table of WHERE clause constraints */
5456 int nOrderBy; /* Number of terms in the ORDER BY clause */
5457 struct sqlite3_index_orderby {
5458 int iColumn; /* Column number */
5459 unsigned char desc; /* True for DESC. False for ASC. */
5460 } *aOrderBy; /* The ORDER BY clause */
5461 /* Outputs */
5462 struct sqlite3_index_constraint_usage {
5463 int argvIndex; /* if >0, constraint is part of argv to xFilter */
5464 unsigned char omit; /* Do not code a test for this constraint */
5465 } *aConstraintUsage;
5466 int idxNum; /* Number used to identify the index */
5467 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
5468 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
5469 int orderByConsumed; /* True if output is already ordered */
5470 double estimatedCost; /* Estimated cost of using this index */
5471 /* Fields below are only available in SQLite 3.8.2 and later */
5472 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */
5476 ** CAPI3REF: Virtual Table Constraint Operator Codes
5478 ** These macros defined the allowed values for the
5479 ** [sqlite3_index_info].aConstraint[].op field. Each value represents
5480 ** an operator that is part of a constraint term in the wHERE clause of
5481 ** a query that uses a [virtual table].
5483 #define SQLITE_INDEX_CONSTRAINT_EQ 2
5484 #define SQLITE_INDEX_CONSTRAINT_GT 4
5485 #define SQLITE_INDEX_CONSTRAINT_LE 8
5486 #define SQLITE_INDEX_CONSTRAINT_LT 16
5487 #define SQLITE_INDEX_CONSTRAINT_GE 32
5488 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
5491 ** CAPI3REF: Register A Virtual Table Implementation
5493 ** ^These routines are used to register a new [virtual table module] name.
5494 ** ^Module names must be registered before
5495 ** creating a new [virtual table] using the module and before using a
5496 ** preexisting [virtual table] for the module.
5498 ** ^The module name is registered on the [database connection] specified
5499 ** by the first parameter. ^The name of the module is given by the
5500 ** second parameter. ^The third parameter is a pointer to
5501 ** the implementation of the [virtual table module]. ^The fourth
5502 ** parameter is an arbitrary client data pointer that is passed through
5503 ** into the [xCreate] and [xConnect] methods of the virtual table module
5504 ** when a new virtual table is be being created or reinitialized.
5506 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
5507 ** is a pointer to a destructor for the pClientData. ^SQLite will
5508 ** invoke the destructor function (if it is not NULL) when SQLite
5509 ** no longer needs the pClientData pointer. ^The destructor will also
5510 ** be invoked if the call to sqlite3_create_module_v2() fails.
5511 ** ^The sqlite3_create_module()
5512 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
5513 ** destructor.
5515 int sqlite3_create_module(
5516 sqlite3 *db, /* SQLite connection to register module with */
5517 const char *zName, /* Name of the module */
5518 const sqlite3_module *p, /* Methods for the module */
5519 void *pClientData /* Client data for xCreate/xConnect */
5521 int sqlite3_create_module_v2(
5522 sqlite3 *db, /* SQLite connection to register module with */
5523 const char *zName, /* Name of the module */
5524 const sqlite3_module *p, /* Methods for the module */
5525 void *pClientData, /* Client data for xCreate/xConnect */
5526 void(*xDestroy)(void*) /* Module destructor function */
5530 ** CAPI3REF: Virtual Table Instance Object
5531 ** KEYWORDS: sqlite3_vtab
5533 ** Every [virtual table module] implementation uses a subclass
5534 ** of this object to describe a particular instance
5535 ** of the [virtual table]. Each subclass will
5536 ** be tailored to the specific needs of the module implementation.
5537 ** The purpose of this superclass is to define certain fields that are
5538 ** common to all module implementations.
5540 ** ^Virtual tables methods can set an error message by assigning a
5541 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
5542 ** take care that any prior string is freed by a call to [sqlite3_free()]
5543 ** prior to assigning a new string to zErrMsg. ^After the error message
5544 ** is delivered up to the client application, the string will be automatically
5545 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
5547 struct sqlite3_vtab {
5548 const sqlite3_module *pModule; /* The module for this virtual table */
5549 int nRef; /* NO LONGER USED */
5550 char *zErrMsg; /* Error message from sqlite3_mprintf() */
5551 /* Virtual table implementations will typically add additional fields */
5555 ** CAPI3REF: Virtual Table Cursor Object
5556 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
5558 ** Every [virtual table module] implementation uses a subclass of the
5559 ** following structure to describe cursors that point into the
5560 ** [virtual table] and are used
5561 ** to loop through the virtual table. Cursors are created using the
5562 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
5563 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
5564 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
5565 ** of the module. Each module implementation will define
5566 ** the content of a cursor structure to suit its own needs.
5568 ** This superclass exists in order to define fields of the cursor that
5569 ** are common to all implementations.
5571 struct sqlite3_vtab_cursor {
5572 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
5573 /* Virtual table implementations will typically add additional fields */
5577 ** CAPI3REF: Declare The Schema Of A Virtual Table
5579 ** ^The [xCreate] and [xConnect] methods of a
5580 ** [virtual table module] call this interface
5581 ** to declare the format (the names and datatypes of the columns) of
5582 ** the virtual tables they implement.
5584 int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
5587 ** CAPI3REF: Overload A Function For A Virtual Table
5589 ** ^(Virtual tables can provide alternative implementations of functions
5590 ** using the [xFindFunction] method of the [virtual table module].
5591 ** But global versions of those functions
5592 ** must exist in order to be overloaded.)^
5594 ** ^(This API makes sure a global version of a function with a particular
5595 ** name and number of parameters exists. If no such function exists
5596 ** before this API is called, a new function is created.)^ ^The implementation
5597 ** of the new function always causes an exception to be thrown. So
5598 ** the new function is not good for anything by itself. Its only
5599 ** purpose is to be a placeholder function that can be overloaded
5600 ** by a [virtual table].
5602 int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
5605 ** The interface to the virtual-table mechanism defined above (back up
5606 ** to a comment remarkably similar to this one) is currently considered
5607 ** to be experimental. The interface might change in incompatible ways.
5608 ** If this is a problem for you, do not use the interface at this time.
5610 ** When the virtual-table mechanism stabilizes, we will declare the
5611 ** interface fixed, support it indefinitely, and remove this comment.
5615 ** CAPI3REF: A Handle To An Open BLOB
5616 ** KEYWORDS: {BLOB handle} {BLOB handles}
5618 ** An instance of this object represents an open BLOB on which
5619 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
5620 ** ^Objects of this type are created by [sqlite3_blob_open()]
5621 ** and destroyed by [sqlite3_blob_close()].
5622 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
5623 ** can be used to read or write small subsections of the BLOB.
5624 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
5626 typedef struct sqlite3_blob sqlite3_blob;
5629 ** CAPI3REF: Open A BLOB For Incremental I/O
5631 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
5632 ** in row iRow, column zColumn, table zTable in database zDb;
5633 ** in other words, the same BLOB that would be selected by:
5635 ** <pre>
5636 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
5637 ** </pre>)^
5639 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
5640 ** and write access. ^If it is zero, the BLOB is opened for read access.
5641 ** ^It is not possible to open a column that is part of an index or primary
5642 ** key for writing. ^If [foreign key constraints] are enabled, it is
5643 ** not possible to open a column that is part of a [child key] for writing.
5645 ** ^Note that the database name is not the filename that contains
5646 ** the database but rather the symbolic name of the database that
5647 ** appears after the AS keyword when the database is connected using [ATTACH].
5648 ** ^For the main database file, the database name is "main".
5649 ** ^For TEMP tables, the database name is "temp".
5651 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
5652 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
5653 ** to be a null pointer.)^
5654 ** ^This function sets the [database connection] error code and message
5655 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
5656 ** functions. ^Note that the *ppBlob variable is always initialized in a
5657 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
5658 ** regardless of the success or failure of this routine.
5660 ** ^(If the row that a BLOB handle points to is modified by an
5661 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
5662 ** then the BLOB handle is marked as "expired".
5663 ** This is true if any column of the row is changed, even a column
5664 ** other than the one the BLOB handle is open on.)^
5665 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
5666 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
5667 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
5668 ** rolled back by the expiration of the BLOB. Such changes will eventually
5669 ** commit if the transaction continues to completion.)^
5671 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
5672 ** the opened blob. ^The size of a blob may not be changed by this
5673 ** interface. Use the [UPDATE] SQL command to change the size of a
5674 ** blob.
5676 ** ^The [sqlite3_blob_open()] interface will fail for a [WITHOUT ROWID]
5677 ** table. Incremental BLOB I/O is not possible on [WITHOUT ROWID] tables.
5679 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
5680 ** and the built-in [zeroblob] SQL function can be used, if desired,
5681 ** to create an empty, zero-filled blob in which to read or write using
5682 ** this interface.
5684 ** To avoid a resource leak, every open [BLOB handle] should eventually
5685 ** be released by a call to [sqlite3_blob_close()].
5687 int sqlite3_blob_open(
5688 sqlite3*,
5689 const char *zDb,
5690 const char *zTable,
5691 const char *zColumn,
5692 sqlite3_int64 iRow,
5693 int flags,
5694 sqlite3_blob **ppBlob
5698 ** CAPI3REF: Move a BLOB Handle to a New Row
5700 ** ^This function is used to move an existing blob handle so that it points
5701 ** to a different row of the same database table. ^The new row is identified
5702 ** by the rowid value passed as the second argument. Only the row can be
5703 ** changed. ^The database, table and column on which the blob handle is open
5704 ** remain the same. Moving an existing blob handle to a new row can be
5705 ** faster than closing the existing handle and opening a new one.
5707 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
5708 ** it must exist and there must be either a blob or text value stored in
5709 ** the nominated column.)^ ^If the new row is not present in the table, or if
5710 ** it does not contain a blob or text value, or if another error occurs, an
5711 ** SQLite error code is returned and the blob handle is considered aborted.
5712 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
5713 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
5714 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
5715 ** always returns zero.
5717 ** ^This function sets the database handle error code and message.
5719 SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
5722 ** CAPI3REF: Close A BLOB Handle
5724 ** ^Closes an open [BLOB handle].
5726 ** ^Closing a BLOB shall cause the current transaction to commit
5727 ** if there are no other BLOBs, no pending prepared statements, and the
5728 ** database connection is in [autocommit mode].
5729 ** ^If any writes were made to the BLOB, they might be held in cache
5730 ** until the close operation if they will fit.
5732 ** ^(Closing the BLOB often forces the changes
5733 ** out to disk and so if any I/O errors occur, they will likely occur
5734 ** at the time when the BLOB is closed. Any errors that occur during
5735 ** closing are reported as a non-zero return value.)^
5737 ** ^(The BLOB is closed unconditionally. Even if this routine returns
5738 ** an error code, the BLOB is still closed.)^
5740 ** ^Calling this routine with a null pointer (such as would be returned
5741 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
5743 int sqlite3_blob_close(sqlite3_blob *);
5746 ** CAPI3REF: Return The Size Of An Open BLOB
5748 ** ^Returns the size in bytes of the BLOB accessible via the
5749 ** successfully opened [BLOB handle] in its only argument. ^The
5750 ** incremental blob I/O routines can only read or overwriting existing
5751 ** blob content; they cannot change the size of a blob.
5753 ** This routine only works on a [BLOB handle] which has been created
5754 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5755 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5756 ** to this routine results in undefined and probably undesirable behavior.
5758 int sqlite3_blob_bytes(sqlite3_blob *);
5761 ** CAPI3REF: Read Data From A BLOB Incrementally
5763 ** ^(This function is used to read data from an open [BLOB handle] into a
5764 ** caller-supplied buffer. N bytes of data are copied into buffer Z
5765 ** from the open BLOB, starting at offset iOffset.)^
5767 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5768 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
5769 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
5770 ** ^The size of the blob (and hence the maximum value of N+iOffset)
5771 ** can be determined using the [sqlite3_blob_bytes()] interface.
5773 ** ^An attempt to read from an expired [BLOB handle] fails with an
5774 ** error code of [SQLITE_ABORT].
5776 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
5777 ** Otherwise, an [error code] or an [extended error code] is returned.)^
5779 ** This routine only works on a [BLOB handle] which has been created
5780 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5781 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5782 ** to this routine results in undefined and probably undesirable behavior.
5784 ** See also: [sqlite3_blob_write()].
5786 int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
5789 ** CAPI3REF: Write Data Into A BLOB Incrementally
5791 ** ^This function is used to write data into an open [BLOB handle] from a
5792 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
5793 ** into the open BLOB, starting at offset iOffset.
5795 ** ^If the [BLOB handle] passed as the first argument was not opened for
5796 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
5797 ** this function returns [SQLITE_READONLY].
5799 ** ^This function may only modify the contents of the BLOB; it is
5800 ** not possible to increase the size of a BLOB using this API.
5801 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5802 ** [SQLITE_ERROR] is returned and no data is written. ^If N is
5803 ** less than zero [SQLITE_ERROR] is returned and no data is written.
5804 ** The size of the BLOB (and hence the maximum value of N+iOffset)
5805 ** can be determined using the [sqlite3_blob_bytes()] interface.
5807 ** ^An attempt to write to an expired [BLOB handle] fails with an
5808 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
5809 ** before the [BLOB handle] expired are not rolled back by the
5810 ** expiration of the handle, though of course those changes might
5811 ** have been overwritten by the statement that expired the BLOB handle
5812 ** or by other independent statements.
5814 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
5815 ** Otherwise, an [error code] or an [extended error code] is returned.)^
5817 ** This routine only works on a [BLOB handle] which has been created
5818 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5819 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5820 ** to this routine results in undefined and probably undesirable behavior.
5822 ** See also: [sqlite3_blob_read()].
5824 int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
5827 ** CAPI3REF: Virtual File System Objects
5829 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
5830 ** that SQLite uses to interact
5831 ** with the underlying operating system. Most SQLite builds come with a
5832 ** single default VFS that is appropriate for the host computer.
5833 ** New VFSes can be registered and existing VFSes can be unregistered.
5834 ** The following interfaces are provided.
5836 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
5837 ** ^Names are case sensitive.
5838 ** ^Names are zero-terminated UTF-8 strings.
5839 ** ^If there is no match, a NULL pointer is returned.
5840 ** ^If zVfsName is NULL then the default VFS is returned.
5842 ** ^New VFSes are registered with sqlite3_vfs_register().
5843 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
5844 ** ^The same VFS can be registered multiple times without injury.
5845 ** ^To make an existing VFS into the default VFS, register it again
5846 ** with the makeDflt flag set. If two different VFSes with the
5847 ** same name are registered, the behavior is undefined. If a
5848 ** VFS is registered with a name that is NULL or an empty string,
5849 ** then the behavior is undefined.
5851 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
5852 ** ^(If the default VFS is unregistered, another VFS is chosen as
5853 ** the default. The choice for the new VFS is arbitrary.)^
5855 sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
5856 int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
5857 int sqlite3_vfs_unregister(sqlite3_vfs*);
5860 ** CAPI3REF: Mutexes
5862 ** The SQLite core uses these routines for thread
5863 ** synchronization. Though they are intended for internal
5864 ** use by SQLite, code that links against SQLite is
5865 ** permitted to use any of these routines.
5867 ** The SQLite source code contains multiple implementations
5868 ** of these mutex routines. An appropriate implementation
5869 ** is selected automatically at compile-time. ^(The following
5870 ** implementations are available in the SQLite core:
5872 ** <ul>
5873 ** <li> SQLITE_MUTEX_PTHREADS
5874 ** <li> SQLITE_MUTEX_W32
5875 ** <li> SQLITE_MUTEX_NOOP
5876 ** </ul>)^
5878 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
5879 ** that does no real locking and is appropriate for use in
5880 ** a single-threaded application. ^The SQLITE_MUTEX_PTHREADS and
5881 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
5882 ** and Windows.
5884 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
5885 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
5886 ** implementation is included with the library. In this case the
5887 ** application must supply a custom mutex implementation using the
5888 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
5889 ** before calling sqlite3_initialize() or any other public sqlite3_
5890 ** function that calls sqlite3_initialize().)^
5892 ** ^The sqlite3_mutex_alloc() routine allocates a new
5893 ** mutex and returns a pointer to it. ^If it returns NULL
5894 ** that means that a mutex could not be allocated. ^SQLite
5895 ** will unwind its stack and return an error. ^(The argument
5896 ** to sqlite3_mutex_alloc() is one of these integer constants:
5898 ** <ul>
5899 ** <li> SQLITE_MUTEX_FAST
5900 ** <li> SQLITE_MUTEX_RECURSIVE
5901 ** <li> SQLITE_MUTEX_STATIC_MASTER
5902 ** <li> SQLITE_MUTEX_STATIC_MEM
5903 ** <li> SQLITE_MUTEX_STATIC_OPEN
5904 ** <li> SQLITE_MUTEX_STATIC_PRNG
5905 ** <li> SQLITE_MUTEX_STATIC_LRU
5906 ** <li> SQLITE_MUTEX_STATIC_PMEM
5907 ** <li> SQLITE_MUTEX_STATIC_APP1
5908 ** <li> SQLITE_MUTEX_STATIC_APP2
5909 ** </ul>)^
5911 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
5912 ** cause sqlite3_mutex_alloc() to create
5913 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
5914 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
5915 ** The mutex implementation does not need to make a distinction
5916 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
5917 ** not want to. ^SQLite will only request a recursive mutex in
5918 ** cases where it really needs one. ^If a faster non-recursive mutex
5919 ** implementation is available on the host platform, the mutex subsystem
5920 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
5922 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
5923 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
5924 ** a pointer to a static preexisting mutex. ^Six static mutexes are
5925 ** used by the current version of SQLite. Future versions of SQLite
5926 ** may add additional static mutexes. Static mutexes are for internal
5927 ** use by SQLite only. Applications that use SQLite mutexes should
5928 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
5929 ** SQLITE_MUTEX_RECURSIVE.
5931 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
5932 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
5933 ** returns a different mutex on every call. ^But for the static
5934 ** mutex types, the same mutex is returned on every call that has
5935 ** the same type number.
5937 ** ^The sqlite3_mutex_free() routine deallocates a previously
5938 ** allocated dynamic mutex. ^SQLite is careful to deallocate every
5939 ** dynamic mutex that it allocates. The dynamic mutexes must not be in
5940 ** use when they are deallocated. Attempting to deallocate a static
5941 ** mutex results in undefined behavior. ^SQLite never deallocates
5942 ** a static mutex.
5944 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
5945 ** to enter a mutex. ^If another thread is already within the mutex,
5946 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
5947 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
5948 ** upon successful entry. ^(Mutexes created using
5949 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
5950 ** In such cases the,
5951 ** mutex must be exited an equal number of times before another thread
5952 ** can enter.)^ ^(If the same thread tries to enter any other
5953 ** kind of mutex more than once, the behavior is undefined.
5954 ** SQLite will never exhibit
5955 ** such behavior in its own use of mutexes.)^
5957 ** ^(Some systems (for example, Windows 95) do not support the operation
5958 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
5959 ** will always return SQLITE_BUSY. The SQLite core only ever uses
5960 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
5962 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
5963 ** previously entered by the same thread. ^(The behavior
5964 ** is undefined if the mutex is not currently entered by the
5965 ** calling thread or is not currently allocated. SQLite will
5966 ** never do either.)^
5968 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
5969 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
5970 ** behave as no-ops.
5972 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
5974 sqlite3_mutex *sqlite3_mutex_alloc(int);
5975 void sqlite3_mutex_free(sqlite3_mutex*);
5976 void sqlite3_mutex_enter(sqlite3_mutex*);
5977 int sqlite3_mutex_try(sqlite3_mutex*);
5978 void sqlite3_mutex_leave(sqlite3_mutex*);
5981 ** CAPI3REF: Mutex Methods Object
5983 ** An instance of this structure defines the low-level routines
5984 ** used to allocate and use mutexes.
5986 ** Usually, the default mutex implementations provided by SQLite are
5987 ** sufficient, however the user has the option of substituting a custom
5988 ** implementation for specialized deployments or systems for which SQLite
5989 ** does not provide a suitable implementation. In this case, the user
5990 ** creates and populates an instance of this structure to pass
5991 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
5992 ** Additionally, an instance of this structure can be used as an
5993 ** output variable when querying the system for the current mutex
5994 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
5996 ** ^The xMutexInit method defined by this structure is invoked as
5997 ** part of system initialization by the sqlite3_initialize() function.
5998 ** ^The xMutexInit routine is called by SQLite exactly once for each
5999 ** effective call to [sqlite3_initialize()].
6001 ** ^The xMutexEnd method defined by this structure is invoked as
6002 ** part of system shutdown by the sqlite3_shutdown() function. The
6003 ** implementation of this method is expected to release all outstanding
6004 ** resources obtained by the mutex methods implementation, especially
6005 ** those obtained by the xMutexInit method. ^The xMutexEnd()
6006 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
6008 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
6009 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
6010 ** xMutexNotheld) implement the following interfaces (respectively):
6012 ** <ul>
6013 ** <li> [sqlite3_mutex_alloc()] </li>
6014 ** <li> [sqlite3_mutex_free()] </li>
6015 ** <li> [sqlite3_mutex_enter()] </li>
6016 ** <li> [sqlite3_mutex_try()] </li>
6017 ** <li> [sqlite3_mutex_leave()] </li>
6018 ** <li> [sqlite3_mutex_held()] </li>
6019 ** <li> [sqlite3_mutex_notheld()] </li>
6020 ** </ul>)^
6022 ** The only difference is that the public sqlite3_XXX functions enumerated
6023 ** above silently ignore any invocations that pass a NULL pointer instead
6024 ** of a valid mutex handle. The implementations of the methods defined
6025 ** by this structure are not required to handle this case, the results
6026 ** of passing a NULL pointer instead of a valid mutex handle are undefined
6027 ** (i.e. it is acceptable to provide an implementation that segfaults if
6028 ** it is passed a NULL pointer).
6030 ** The xMutexInit() method must be threadsafe. ^It must be harmless to
6031 ** invoke xMutexInit() multiple times within the same process and without
6032 ** intervening calls to xMutexEnd(). Second and subsequent calls to
6033 ** xMutexInit() must be no-ops.
6035 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
6036 ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory
6037 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
6038 ** memory allocation for a fast or recursive mutex.
6040 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
6041 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
6042 ** If xMutexInit fails in any way, it is expected to clean up after itself
6043 ** prior to returning.
6045 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
6046 struct sqlite3_mutex_methods {
6047 int (*xMutexInit)(void);
6048 int (*xMutexEnd)(void);
6049 sqlite3_mutex *(*xMutexAlloc)(int);
6050 void (*xMutexFree)(sqlite3_mutex *);
6051 void (*xMutexEnter)(sqlite3_mutex *);
6052 int (*xMutexTry)(sqlite3_mutex *);
6053 void (*xMutexLeave)(sqlite3_mutex *);
6054 int (*xMutexHeld)(sqlite3_mutex *);
6055 int (*xMutexNotheld)(sqlite3_mutex *);
6059 ** CAPI3REF: Mutex Verification Routines
6061 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
6062 ** are intended for use inside assert() statements. ^The SQLite core
6063 ** never uses these routines except inside an assert() and applications
6064 ** are advised to follow the lead of the core. ^The SQLite core only
6065 ** provides implementations for these routines when it is compiled
6066 ** with the SQLITE_DEBUG flag. ^External mutex implementations
6067 ** are only required to provide these routines if SQLITE_DEBUG is
6068 ** defined and if NDEBUG is not defined.
6070 ** ^These routines should return true if the mutex in their argument
6071 ** is held or not held, respectively, by the calling thread.
6073 ** ^The implementation is not required to provide versions of these
6074 ** routines that actually work. If the implementation does not provide working
6075 ** versions of these routines, it should at least provide stubs that always
6076 ** return true so that one does not get spurious assertion failures.
6078 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
6079 ** the routine should return 1. This seems counter-intuitive since
6080 ** clearly the mutex cannot be held if it does not exist. But
6081 ** the reason the mutex does not exist is because the build is not
6082 ** using mutexes. And we do not want the assert() containing the
6083 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
6084 ** the appropriate thing to do. ^The sqlite3_mutex_notheld()
6085 ** interface should also return 1 when given a NULL pointer.
6087 #ifndef NDEBUG
6088 int sqlite3_mutex_held(sqlite3_mutex*);
6089 int sqlite3_mutex_notheld(sqlite3_mutex*);
6090 #endif
6093 ** CAPI3REF: Mutex Types
6095 ** The [sqlite3_mutex_alloc()] interface takes a single argument
6096 ** which is one of these integer constants.
6098 ** The set of static mutexes may change from one SQLite release to the
6099 ** next. Applications that override the built-in mutex logic must be
6100 ** prepared to accommodate additional static mutexes.
6102 #define SQLITE_MUTEX_FAST 0
6103 #define SQLITE_MUTEX_RECURSIVE 1
6104 #define SQLITE_MUTEX_STATIC_MASTER 2
6105 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
6106 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
6107 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
6108 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */
6109 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
6110 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
6111 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
6112 #define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */
6113 #define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */
6114 #define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */
6117 ** CAPI3REF: Retrieve the mutex for a database connection
6119 ** ^This interface returns a pointer the [sqlite3_mutex] object that
6120 ** serializes access to the [database connection] given in the argument
6121 ** when the [threading mode] is Serialized.
6122 ** ^If the [threading mode] is Single-thread or Multi-thread then this
6123 ** routine returns a NULL pointer.
6125 sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
6128 ** CAPI3REF: Low-Level Control Of Database Files
6130 ** ^The [sqlite3_file_control()] interface makes a direct call to the
6131 ** xFileControl method for the [sqlite3_io_methods] object associated
6132 ** with a particular database identified by the second argument. ^The
6133 ** name of the database is "main" for the main database or "temp" for the
6134 ** TEMP database, or the name that appears after the AS keyword for
6135 ** databases that are added using the [ATTACH] SQL command.
6136 ** ^A NULL pointer can be used in place of "main" to refer to the
6137 ** main database file.
6138 ** ^The third and fourth parameters to this routine
6139 ** are passed directly through to the second and third parameters of
6140 ** the xFileControl method. ^The return value of the xFileControl
6141 ** method becomes the return value of this routine.
6143 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
6144 ** a pointer to the underlying [sqlite3_file] object to be written into
6145 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER
6146 ** case is a short-circuit path which does not actually invoke the
6147 ** underlying sqlite3_io_methods.xFileControl method.
6149 ** ^If the second parameter (zDbName) does not match the name of any
6150 ** open database file, then SQLITE_ERROR is returned. ^This error
6151 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
6152 ** or [sqlite3_errmsg()]. The underlying xFileControl method might
6153 ** also return SQLITE_ERROR. There is no way to distinguish between
6154 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
6155 ** xFileControl method.
6157 ** See also: [SQLITE_FCNTL_LOCKSTATE]
6159 int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
6162 ** CAPI3REF: Testing Interface
6164 ** ^The sqlite3_test_control() interface is used to read out internal
6165 ** state of SQLite and to inject faults into SQLite for testing
6166 ** purposes. ^The first parameter is an operation code that determines
6167 ** the number, meaning, and operation of all subsequent parameters.
6169 ** This interface is not for use by applications. It exists solely
6170 ** for verifying the correct operation of the SQLite library. Depending
6171 ** on how the SQLite library is compiled, this interface might not exist.
6173 ** The details of the operation codes, their meanings, the parameters
6174 ** they take, and what they do are all subject to change without notice.
6175 ** Unlike most of the SQLite API, this function is not guaranteed to
6176 ** operate consistently from one release to the next.
6178 int sqlite3_test_control(int op, ...);
6181 ** CAPI3REF: Testing Interface Operation Codes
6183 ** These constants are the valid operation code parameters used
6184 ** as the first argument to [sqlite3_test_control()].
6186 ** These parameters and their meanings are subject to change
6187 ** without notice. These values are for testing purposes only.
6188 ** Applications should not use any of these parameters or the
6189 ** [sqlite3_test_control()] interface.
6191 #define SQLITE_TESTCTRL_FIRST 5
6192 #define SQLITE_TESTCTRL_PRNG_SAVE 5
6193 #define SQLITE_TESTCTRL_PRNG_RESTORE 6
6194 #define SQLITE_TESTCTRL_PRNG_RESET 7
6195 #define SQLITE_TESTCTRL_BITVEC_TEST 8
6196 #define SQLITE_TESTCTRL_FAULT_INSTALL 9
6197 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
6198 #define SQLITE_TESTCTRL_PENDING_BYTE 11
6199 #define SQLITE_TESTCTRL_ASSERT 12
6200 #define SQLITE_TESTCTRL_ALWAYS 13
6201 #define SQLITE_TESTCTRL_RESERVE 14
6202 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
6203 #define SQLITE_TESTCTRL_ISKEYWORD 16
6204 #define SQLITE_TESTCTRL_SCRATCHMALLOC 17
6205 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
6206 #define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */
6207 #define SQLITE_TESTCTRL_NEVER_CORRUPT 20
6208 #define SQLITE_TESTCTRL_VDBE_COVERAGE 21
6209 #define SQLITE_TESTCTRL_BYTEORDER 22
6210 #define SQLITE_TESTCTRL_ISINIT 23
6211 #define SQLITE_TESTCTRL_SORTER_MMAP 24
6212 #define SQLITE_TESTCTRL_LAST 24
6215 ** CAPI3REF: SQLite Runtime Status
6217 ** ^This interface is used to retrieve runtime status information
6218 ** about the performance of SQLite, and optionally to reset various
6219 ** highwater marks. ^The first argument is an integer code for
6220 ** the specific parameter to measure. ^(Recognized integer codes
6221 ** are of the form [status parameters | SQLITE_STATUS_...].)^
6222 ** ^The current value of the parameter is returned into *pCurrent.
6223 ** ^The highest recorded value is returned in *pHighwater. ^If the
6224 ** resetFlag is true, then the highest record value is reset after
6225 ** *pHighwater is written. ^(Some parameters do not record the highest
6226 ** value. For those parameters
6227 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
6228 ** ^(Other parameters record only the highwater mark and not the current
6229 ** value. For these latter parameters nothing is written into *pCurrent.)^
6231 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a
6232 ** non-zero [error code] on failure.
6234 ** This routine is threadsafe but is not atomic. This routine can be
6235 ** called while other threads are running the same or different SQLite
6236 ** interfaces. However the values returned in *pCurrent and
6237 ** *pHighwater reflect the status of SQLite at different points in time
6238 ** and it is possible that another thread might change the parameter
6239 ** in between the times when *pCurrent and *pHighwater are written.
6241 ** See also: [sqlite3_db_status()]
6243 int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
6247 ** CAPI3REF: Status Parameters
6248 ** KEYWORDS: {status parameters}
6250 ** These integer constants designate various run-time status parameters
6251 ** that can be returned by [sqlite3_status()].
6253 ** <dl>
6254 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
6255 ** <dd>This parameter is the current amount of memory checked out
6256 ** using [sqlite3_malloc()], either directly or indirectly. The
6257 ** figure includes calls made to [sqlite3_malloc()] by the application
6258 ** and internal memory usage by the SQLite library. Scratch memory
6259 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
6260 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
6261 ** this parameter. The amount returned is the sum of the allocation
6262 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
6264 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
6265 ** <dd>This parameter records the largest memory allocation request
6266 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
6267 ** internal equivalents). Only the value returned in the
6268 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6269 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6271 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
6272 ** <dd>This parameter records the number of separate memory allocations
6273 ** currently checked out.</dd>)^
6275 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
6276 ** <dd>This parameter returns the number of pages used out of the
6277 ** [pagecache memory allocator] that was configured using
6278 ** [SQLITE_CONFIG_PAGECACHE]. The
6279 ** value returned is in pages, not in bytes.</dd>)^
6281 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
6282 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
6283 ** <dd>This parameter returns the number of bytes of page cache
6284 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
6285 ** buffer and where forced to overflow to [sqlite3_malloc()]. The
6286 ** returned value includes allocations that overflowed because they
6287 ** where too large (they were larger than the "sz" parameter to
6288 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
6289 ** no space was left in the page cache.</dd>)^
6291 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
6292 ** <dd>This parameter records the largest memory allocation request
6293 ** handed to [pagecache memory allocator]. Only the value returned in the
6294 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6295 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6297 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
6298 ** <dd>This parameter returns the number of allocations used out of the
6299 ** [scratch memory allocator] configured using
6300 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not
6301 ** in bytes. Since a single thread may only have one scratch allocation
6302 ** outstanding at time, this parameter also reports the number of threads
6303 ** using scratch memory at the same time.</dd>)^
6305 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
6306 ** <dd>This parameter returns the number of bytes of scratch memory
6307 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
6308 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values
6309 ** returned include overflows because the requested allocation was too
6310 ** larger (that is, because the requested allocation was larger than the
6311 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
6312 ** slots were available.
6313 ** </dd>)^
6315 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
6316 ** <dd>This parameter records the largest memory allocation request
6317 ** handed to [scratch memory allocator]. Only the value returned in the
6318 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6319 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6321 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
6322 ** <dd>This parameter records the deepest parser stack. It is only
6323 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
6324 ** </dl>
6326 ** New status parameters may be added from time to time.
6328 #define SQLITE_STATUS_MEMORY_USED 0
6329 #define SQLITE_STATUS_PAGECACHE_USED 1
6330 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
6331 #define SQLITE_STATUS_SCRATCH_USED 3
6332 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4
6333 #define SQLITE_STATUS_MALLOC_SIZE 5
6334 #define SQLITE_STATUS_PARSER_STACK 6
6335 #define SQLITE_STATUS_PAGECACHE_SIZE 7
6336 #define SQLITE_STATUS_SCRATCH_SIZE 8
6337 #define SQLITE_STATUS_MALLOC_COUNT 9
6340 ** CAPI3REF: Database Connection Status
6342 ** ^This interface is used to retrieve runtime status information
6343 ** about a single [database connection]. ^The first argument is the
6344 ** database connection object to be interrogated. ^The second argument
6345 ** is an integer constant, taken from the set of
6346 ** [SQLITE_DBSTATUS options], that
6347 ** determines the parameter to interrogate. The set of
6348 ** [SQLITE_DBSTATUS options] is likely
6349 ** to grow in future releases of SQLite.
6351 ** ^The current value of the requested parameter is written into *pCur
6352 ** and the highest instantaneous value is written into *pHiwtr. ^If
6353 ** the resetFlg is true, then the highest instantaneous value is
6354 ** reset back down to the current value.
6356 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
6357 ** non-zero [error code] on failure.
6359 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
6361 int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
6364 ** CAPI3REF: Status Parameters for database connections
6365 ** KEYWORDS: {SQLITE_DBSTATUS options}
6367 ** These constants are the available integer "verbs" that can be passed as
6368 ** the second argument to the [sqlite3_db_status()] interface.
6370 ** New verbs may be added in future releases of SQLite. Existing verbs
6371 ** might be discontinued. Applications should check the return code from
6372 ** [sqlite3_db_status()] to make sure that the call worked.
6373 ** The [sqlite3_db_status()] interface will return a non-zero error code
6374 ** if a discontinued or unsupported verb is invoked.
6376 ** <dl>
6377 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
6378 ** <dd>This parameter returns the number of lookaside memory slots currently
6379 ** checked out.</dd>)^
6381 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
6382 ** <dd>This parameter returns the number malloc attempts that were
6383 ** satisfied using lookaside memory. Only the high-water value is meaningful;
6384 ** the current value is always zero.)^
6386 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
6387 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
6388 ** <dd>This parameter returns the number malloc attempts that might have
6389 ** been satisfied using lookaside memory but failed due to the amount of
6390 ** memory requested being larger than the lookaside slot size.
6391 ** Only the high-water value is meaningful;
6392 ** the current value is always zero.)^
6394 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
6395 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
6396 ** <dd>This parameter returns the number malloc attempts that might have
6397 ** been satisfied using lookaside memory but failed due to all lookaside
6398 ** memory already being in use.
6399 ** Only the high-water value is meaningful;
6400 ** the current value is always zero.)^
6402 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
6403 ** <dd>This parameter returns the approximate number of bytes of heap
6404 ** memory used by all pager caches associated with the database connection.)^
6405 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
6407 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
6408 ** <dd>This parameter returns the approximate number of bytes of heap
6409 ** memory used to store the schema for all databases associated
6410 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
6411 ** ^The full amount of memory used by the schemas is reported, even if the
6412 ** schema memory is shared with other database connections due to
6413 ** [shared cache mode] being enabled.
6414 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
6416 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
6417 ** <dd>This parameter returns the approximate number of bytes of heap
6418 ** and lookaside memory used by all prepared statements associated with
6419 ** the database connection.)^
6420 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
6421 ** </dd>
6423 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
6424 ** <dd>This parameter returns the number of pager cache hits that have
6425 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
6426 ** is always 0.
6427 ** </dd>
6429 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
6430 ** <dd>This parameter returns the number of pager cache misses that have
6431 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
6432 ** is always 0.
6433 ** </dd>
6435 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
6436 ** <dd>This parameter returns the number of dirty cache entries that have
6437 ** been written to disk. Specifically, the number of pages written to the
6438 ** wal file in wal mode databases, or the number of pages written to the
6439 ** database file in rollback mode databases. Any pages written as part of
6440 ** transaction rollback or database recovery operations are not included.
6441 ** If an IO or other error occurs while writing a page to disk, the effect
6442 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
6443 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
6444 ** </dd>
6446 ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
6447 ** <dd>This parameter returns zero for the current value if and only if
6448 ** all foreign key constraints (deferred or immediate) have been
6449 ** resolved.)^ ^The highwater mark is always 0.
6450 ** </dd>
6451 ** </dl>
6453 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
6454 #define SQLITE_DBSTATUS_CACHE_USED 1
6455 #define SQLITE_DBSTATUS_SCHEMA_USED 2
6456 #define SQLITE_DBSTATUS_STMT_USED 3
6457 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
6458 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
6459 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
6460 #define SQLITE_DBSTATUS_CACHE_HIT 7
6461 #define SQLITE_DBSTATUS_CACHE_MISS 8
6462 #define SQLITE_DBSTATUS_CACHE_WRITE 9
6463 #define SQLITE_DBSTATUS_DEFERRED_FKS 10
6464 #define SQLITE_DBSTATUS_MAX 10 /* Largest defined DBSTATUS */
6468 ** CAPI3REF: Prepared Statement Status
6470 ** ^(Each prepared statement maintains various
6471 ** [SQLITE_STMTSTATUS counters] that measure the number
6472 ** of times it has performed specific operations.)^ These counters can
6473 ** be used to monitor the performance characteristics of the prepared
6474 ** statements. For example, if the number of table steps greatly exceeds
6475 ** the number of table searches or result rows, that would tend to indicate
6476 ** that the prepared statement is using a full table scan rather than
6477 ** an index.
6479 ** ^(This interface is used to retrieve and reset counter values from
6480 ** a [prepared statement]. The first argument is the prepared statement
6481 ** object to be interrogated. The second argument
6482 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
6483 ** to be interrogated.)^
6484 ** ^The current value of the requested counter is returned.
6485 ** ^If the resetFlg is true, then the counter is reset to zero after this
6486 ** interface call returns.
6488 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
6490 int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
6493 ** CAPI3REF: Status Parameters for prepared statements
6494 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
6496 ** These preprocessor macros define integer codes that name counter
6497 ** values associated with the [sqlite3_stmt_status()] interface.
6498 ** The meanings of the various counters are as follows:
6500 ** <dl>
6501 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
6502 ** <dd>^This is the number of times that SQLite has stepped forward in
6503 ** a table as part of a full table scan. Large numbers for this counter
6504 ** may indicate opportunities for performance improvement through
6505 ** careful use of indices.</dd>
6507 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
6508 ** <dd>^This is the number of sort operations that have occurred.
6509 ** A non-zero value in this counter may indicate an opportunity to
6510 ** improvement performance through careful use of indices.</dd>
6512 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
6513 ** <dd>^This is the number of rows inserted into transient indices that
6514 ** were created automatically in order to help joins run faster.
6515 ** A non-zero value in this counter may indicate an opportunity to
6516 ** improvement performance by adding permanent indices that do not
6517 ** need to be reinitialized each time the statement is run.</dd>
6519 ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
6520 ** <dd>^This is the number of virtual machine operations executed
6521 ** by the prepared statement if that number is less than or equal
6522 ** to 2147483647. The number of virtual machine operations can be
6523 ** used as a proxy for the total work done by the prepared statement.
6524 ** If the number of virtual machine operations exceeds 2147483647
6525 ** then the value returned by this statement status code is undefined.
6526 ** </dd>
6527 ** </dl>
6529 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
6530 #define SQLITE_STMTSTATUS_SORT 2
6531 #define SQLITE_STMTSTATUS_AUTOINDEX 3
6532 #define SQLITE_STMTSTATUS_VM_STEP 4
6535 ** CAPI3REF: Custom Page Cache Object
6537 ** The sqlite3_pcache type is opaque. It is implemented by
6538 ** the pluggable module. The SQLite core has no knowledge of
6539 ** its size or internal structure and never deals with the
6540 ** sqlite3_pcache object except by holding and passing pointers
6541 ** to the object.
6543 ** See [sqlite3_pcache_methods2] for additional information.
6545 typedef struct sqlite3_pcache sqlite3_pcache;
6548 ** CAPI3REF: Custom Page Cache Object
6550 ** The sqlite3_pcache_page object represents a single page in the
6551 ** page cache. The page cache will allocate instances of this
6552 ** object. Various methods of the page cache use pointers to instances
6553 ** of this object as parameters or as their return value.
6555 ** See [sqlite3_pcache_methods2] for additional information.
6557 typedef struct sqlite3_pcache_page sqlite3_pcache_page;
6558 struct sqlite3_pcache_page {
6559 void *pBuf; /* The content of the page */
6560 void *pExtra; /* Extra information associated with the page */
6564 ** CAPI3REF: Application Defined Page Cache.
6565 ** KEYWORDS: {page cache}
6567 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
6568 ** register an alternative page cache implementation by passing in an
6569 ** instance of the sqlite3_pcache_methods2 structure.)^
6570 ** In many applications, most of the heap memory allocated by
6571 ** SQLite is used for the page cache.
6572 ** By implementing a
6573 ** custom page cache using this API, an application can better control
6574 ** the amount of memory consumed by SQLite, the way in which
6575 ** that memory is allocated and released, and the policies used to
6576 ** determine exactly which parts of a database file are cached and for
6577 ** how long.
6579 ** The alternative page cache mechanism is an
6580 ** extreme measure that is only needed by the most demanding applications.
6581 ** The built-in page cache is recommended for most uses.
6583 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
6584 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
6585 ** the application may discard the parameter after the call to
6586 ** [sqlite3_config()] returns.)^
6588 ** [[the xInit() page cache method]]
6589 ** ^(The xInit() method is called once for each effective
6590 ** call to [sqlite3_initialize()])^
6591 ** (usually only once during the lifetime of the process). ^(The xInit()
6592 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
6593 ** The intent of the xInit() method is to set up global data structures
6594 ** required by the custom page cache implementation.
6595 ** ^(If the xInit() method is NULL, then the
6596 ** built-in default page cache is used instead of the application defined
6597 ** page cache.)^
6599 ** [[the xShutdown() page cache method]]
6600 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
6601 ** It can be used to clean up
6602 ** any outstanding resources before process shutdown, if required.
6603 ** ^The xShutdown() method may be NULL.
6605 ** ^SQLite automatically serializes calls to the xInit method,
6606 ** so the xInit method need not be threadsafe. ^The
6607 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
6608 ** not need to be threadsafe either. All other methods must be threadsafe
6609 ** in multithreaded applications.
6611 ** ^SQLite will never invoke xInit() more than once without an intervening
6612 ** call to xShutdown().
6614 ** [[the xCreate() page cache methods]]
6615 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
6616 ** SQLite will typically create one cache instance for each open database file,
6617 ** though this is not guaranteed. ^The
6618 ** first parameter, szPage, is the size in bytes of the pages that must
6619 ** be allocated by the cache. ^szPage will always a power of two. ^The
6620 ** second parameter szExtra is a number of bytes of extra storage
6621 ** associated with each page cache entry. ^The szExtra parameter will
6622 ** a number less than 250. SQLite will use the
6623 ** extra szExtra bytes on each page to store metadata about the underlying
6624 ** database page on disk. The value passed into szExtra depends
6625 ** on the SQLite version, the target platform, and how SQLite was compiled.
6626 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
6627 ** created will be used to cache database pages of a file stored on disk, or
6628 ** false if it is used for an in-memory database. The cache implementation
6629 ** does not have to do anything special based with the value of bPurgeable;
6630 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
6631 ** never invoke xUnpin() except to deliberately delete a page.
6632 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
6633 ** false will always have the "discard" flag set to true.
6634 ** ^Hence, a cache created with bPurgeable false will
6635 ** never contain any unpinned pages.
6637 ** [[the xCachesize() page cache method]]
6638 ** ^(The xCachesize() method may be called at any time by SQLite to set the
6639 ** suggested maximum cache-size (number of pages stored by) the cache
6640 ** instance passed as the first argument. This is the value configured using
6641 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
6642 ** parameter, the implementation is not required to do anything with this
6643 ** value; it is advisory only.
6645 ** [[the xPagecount() page cache methods]]
6646 ** The xPagecount() method must return the number of pages currently
6647 ** stored in the cache, both pinned and unpinned.
6649 ** [[the xFetch() page cache methods]]
6650 ** The xFetch() method locates a page in the cache and returns a pointer to
6651 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
6652 ** The pBuf element of the returned sqlite3_pcache_page object will be a
6653 ** pointer to a buffer of szPage bytes used to store the content of a
6654 ** single database page. The pExtra element of sqlite3_pcache_page will be
6655 ** a pointer to the szExtra bytes of extra storage that SQLite has requested
6656 ** for each entry in the page cache.
6658 ** The page to be fetched is determined by the key. ^The minimum key value
6659 ** is 1. After it has been retrieved using xFetch, the page is considered
6660 ** to be "pinned".
6662 ** If the requested page is already in the page cache, then the page cache
6663 ** implementation must return a pointer to the page buffer with its content
6664 ** intact. If the requested page is not already in the cache, then the
6665 ** cache implementation should use the value of the createFlag
6666 ** parameter to help it determined what action to take:
6668 ** <table border=1 width=85% align=center>
6669 ** <tr><th> createFlag <th> Behavior when page is not already in cache
6670 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
6671 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
6672 ** Otherwise return NULL.
6673 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
6674 ** NULL if allocating a new page is effectively impossible.
6675 ** </table>
6677 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
6678 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
6679 ** failed.)^ In between the to xFetch() calls, SQLite may
6680 ** attempt to unpin one or more cache pages by spilling the content of
6681 ** pinned pages to disk and synching the operating system disk cache.
6683 ** [[the xUnpin() page cache method]]
6684 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
6685 ** as its second argument. If the third parameter, discard, is non-zero,
6686 ** then the page must be evicted from the cache.
6687 ** ^If the discard parameter is
6688 ** zero, then the page may be discarded or retained at the discretion of
6689 ** page cache implementation. ^The page cache implementation
6690 ** may choose to evict unpinned pages at any time.
6692 ** The cache must not perform any reference counting. A single
6693 ** call to xUnpin() unpins the page regardless of the number of prior calls
6694 ** to xFetch().
6696 ** [[the xRekey() page cache methods]]
6697 ** The xRekey() method is used to change the key value associated with the
6698 ** page passed as the second argument. If the cache
6699 ** previously contains an entry associated with newKey, it must be
6700 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
6701 ** to be pinned.
6703 ** When SQLite calls the xTruncate() method, the cache must discard all
6704 ** existing cache entries with page numbers (keys) greater than or equal
6705 ** to the value of the iLimit parameter passed to xTruncate(). If any
6706 ** of these pages are pinned, they are implicitly unpinned, meaning that
6707 ** they can be safely discarded.
6709 ** [[the xDestroy() page cache method]]
6710 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
6711 ** All resources associated with the specified cache should be freed. ^After
6712 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
6713 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
6714 ** functions.
6716 ** [[the xShrink() page cache method]]
6717 ** ^SQLite invokes the xShrink() method when it wants the page cache to
6718 ** free up as much of heap memory as possible. The page cache implementation
6719 ** is not obligated to free any memory, but well-behaved implementations should
6720 ** do their best.
6722 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
6723 struct sqlite3_pcache_methods2 {
6724 int iVersion;
6725 void *pArg;
6726 int (*xInit)(void*);
6727 void (*xShutdown)(void*);
6728 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
6729 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6730 int (*xPagecount)(sqlite3_pcache*);
6731 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6732 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
6733 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
6734 unsigned oldKey, unsigned newKey);
6735 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6736 void (*xDestroy)(sqlite3_pcache*);
6737 void (*xShrink)(sqlite3_pcache*);
6741 ** This is the obsolete pcache_methods object that has now been replaced
6742 ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
6743 ** retained in the header file for backwards compatibility only.
6745 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
6746 struct sqlite3_pcache_methods {
6747 void *pArg;
6748 int (*xInit)(void*);
6749 void (*xShutdown)(void*);
6750 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
6751 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6752 int (*xPagecount)(sqlite3_pcache*);
6753 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6754 void (*xUnpin)(sqlite3_pcache*, void*, int discard);
6755 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
6756 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6757 void (*xDestroy)(sqlite3_pcache*);
6762 ** CAPI3REF: Online Backup Object
6764 ** The sqlite3_backup object records state information about an ongoing
6765 ** online backup operation. ^The sqlite3_backup object is created by
6766 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
6767 ** [sqlite3_backup_finish()].
6769 ** See Also: [Using the SQLite Online Backup API]
6771 typedef struct sqlite3_backup sqlite3_backup;
6774 ** CAPI3REF: Online Backup API.
6776 ** The backup API copies the content of one database into another.
6777 ** It is useful either for creating backups of databases or
6778 ** for copying in-memory databases to or from persistent files.
6780 ** See Also: [Using the SQLite Online Backup API]
6782 ** ^SQLite holds a write transaction open on the destination database file
6783 ** for the duration of the backup operation.
6784 ** ^The source database is read-locked only while it is being read;
6785 ** it is not locked continuously for the entire backup operation.
6786 ** ^Thus, the backup may be performed on a live source database without
6787 ** preventing other database connections from
6788 ** reading or writing to the source database while the backup is underway.
6790 ** ^(To perform a backup operation:
6791 ** <ol>
6792 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
6793 ** backup,
6794 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
6795 ** the data between the two databases, and finally
6796 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
6797 ** associated with the backup operation.
6798 ** </ol>)^
6799 ** There should be exactly one call to sqlite3_backup_finish() for each
6800 ** successful call to sqlite3_backup_init().
6802 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
6804 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
6805 ** [database connection] associated with the destination database
6806 ** and the database name, respectively.
6807 ** ^The database name is "main" for the main database, "temp" for the
6808 ** temporary database, or the name specified after the AS keyword in
6809 ** an [ATTACH] statement for an attached database.
6810 ** ^The S and M arguments passed to
6811 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
6812 ** and database name of the source database, respectively.
6813 ** ^The source and destination [database connections] (parameters S and D)
6814 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
6815 ** an error.
6817 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
6818 ** returned and an error code and error message are stored in the
6819 ** destination [database connection] D.
6820 ** ^The error code and message for the failed call to sqlite3_backup_init()
6821 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
6822 ** [sqlite3_errmsg16()] functions.
6823 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
6824 ** [sqlite3_backup] object.
6825 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
6826 ** sqlite3_backup_finish() functions to perform the specified backup
6827 ** operation.
6829 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
6831 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
6832 ** the source and destination databases specified by [sqlite3_backup] object B.
6833 ** ^If N is negative, all remaining source pages are copied.
6834 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
6835 ** are still more pages to be copied, then the function returns [SQLITE_OK].
6836 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
6837 ** from source to destination, then it returns [SQLITE_DONE].
6838 ** ^If an error occurs while running sqlite3_backup_step(B,N),
6839 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
6840 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
6841 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
6842 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
6844 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
6845 ** <ol>
6846 ** <li> the destination database was opened read-only, or
6847 ** <li> the destination database is using write-ahead-log journaling
6848 ** and the destination and source page sizes differ, or
6849 ** <li> the destination database is an in-memory database and the
6850 ** destination and source page sizes differ.
6851 ** </ol>)^
6853 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
6854 ** the [sqlite3_busy_handler | busy-handler function]
6855 ** is invoked (if one is specified). ^If the
6856 ** busy-handler returns non-zero before the lock is available, then
6857 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
6858 ** sqlite3_backup_step() can be retried later. ^If the source
6859 ** [database connection]
6860 ** is being used to write to the source database when sqlite3_backup_step()
6861 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
6862 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
6863 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
6864 ** [SQLITE_READONLY] is returned, then
6865 ** there is no point in retrying the call to sqlite3_backup_step(). These
6866 ** errors are considered fatal.)^ The application must accept
6867 ** that the backup operation has failed and pass the backup operation handle
6868 ** to the sqlite3_backup_finish() to release associated resources.
6870 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
6871 ** on the destination file. ^The exclusive lock is not released until either
6872 ** sqlite3_backup_finish() is called or the backup operation is complete
6873 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
6874 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
6875 ** lasts for the duration of the sqlite3_backup_step() call.
6876 ** ^Because the source database is not locked between calls to
6877 ** sqlite3_backup_step(), the source database may be modified mid-way
6878 ** through the backup process. ^If the source database is modified by an
6879 ** external process or via a database connection other than the one being
6880 ** used by the backup operation, then the backup will be automatically
6881 ** restarted by the next call to sqlite3_backup_step(). ^If the source
6882 ** database is modified by the using the same database connection as is used
6883 ** by the backup operation, then the backup database is automatically
6884 ** updated at the same time.
6886 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
6888 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
6889 ** application wishes to abandon the backup operation, the application
6890 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
6891 ** ^The sqlite3_backup_finish() interfaces releases all
6892 ** resources associated with the [sqlite3_backup] object.
6893 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
6894 ** active write-transaction on the destination database is rolled back.
6895 ** The [sqlite3_backup] object is invalid
6896 ** and may not be used following a call to sqlite3_backup_finish().
6898 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
6899 ** sqlite3_backup_step() errors occurred, regardless or whether or not
6900 ** sqlite3_backup_step() completed.
6901 ** ^If an out-of-memory condition or IO error occurred during any prior
6902 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
6903 ** sqlite3_backup_finish() returns the corresponding [error code].
6905 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
6906 ** is not a permanent error and does not affect the return value of
6907 ** sqlite3_backup_finish().
6909 ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]
6910 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
6912 ** ^Each call to sqlite3_backup_step() sets two values inside
6913 ** the [sqlite3_backup] object: the number of pages still to be backed
6914 ** up and the total number of pages in the source database file.
6915 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
6916 ** retrieve these two values, respectively.
6918 ** ^The values returned by these functions are only updated by
6919 ** sqlite3_backup_step(). ^If the source database is modified during a backup
6920 ** operation, then the values are not updated to account for any extra
6921 ** pages that need to be updated or the size of the source database file
6922 ** changing.
6924 ** <b>Concurrent Usage of Database Handles</b>
6926 ** ^The source [database connection] may be used by the application for other
6927 ** purposes while a backup operation is underway or being initialized.
6928 ** ^If SQLite is compiled and configured to support threadsafe database
6929 ** connections, then the source database connection may be used concurrently
6930 ** from within other threads.
6932 ** However, the application must guarantee that the destination
6933 ** [database connection] is not passed to any other API (by any thread) after
6934 ** sqlite3_backup_init() is called and before the corresponding call to
6935 ** sqlite3_backup_finish(). SQLite does not currently check to see
6936 ** if the application incorrectly accesses the destination [database connection]
6937 ** and so no error code is reported, but the operations may malfunction
6938 ** nevertheless. Use of the destination database connection while a
6939 ** backup is in progress might also also cause a mutex deadlock.
6941 ** If running in [shared cache mode], the application must
6942 ** guarantee that the shared cache used by the destination database
6943 ** is not accessed while the backup is running. In practice this means
6944 ** that the application must guarantee that the disk file being
6945 ** backed up to is not accessed by any connection within the process,
6946 ** not just the specific connection that was passed to sqlite3_backup_init().
6948 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
6949 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
6950 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
6951 ** APIs are not strictly speaking threadsafe. If they are invoked at the
6952 ** same time as another thread is invoking sqlite3_backup_step() it is
6953 ** possible that they return invalid values.
6955 sqlite3_backup *sqlite3_backup_init(
6956 sqlite3 *pDest, /* Destination database handle */
6957 const char *zDestName, /* Destination database name */
6958 sqlite3 *pSource, /* Source database handle */
6959 const char *zSourceName /* Source database name */
6961 int sqlite3_backup_step(sqlite3_backup *p, int nPage);
6962 int sqlite3_backup_finish(sqlite3_backup *p);
6963 int sqlite3_backup_remaining(sqlite3_backup *p);
6964 int sqlite3_backup_pagecount(sqlite3_backup *p);
6967 ** CAPI3REF: Unlock Notification
6969 ** ^When running in shared-cache mode, a database operation may fail with
6970 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
6971 ** individual tables within the shared-cache cannot be obtained. See
6972 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
6973 ** ^This API may be used to register a callback that SQLite will invoke
6974 ** when the connection currently holding the required lock relinquishes it.
6975 ** ^This API is only available if the library was compiled with the
6976 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
6978 ** See Also: [Using the SQLite Unlock Notification Feature].
6980 ** ^Shared-cache locks are released when a database connection concludes
6981 ** its current transaction, either by committing it or rolling it back.
6983 ** ^When a connection (known as the blocked connection) fails to obtain a
6984 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
6985 ** identity of the database connection (the blocking connection) that
6986 ** has locked the required resource is stored internally. ^After an
6987 ** application receives an SQLITE_LOCKED error, it may call the
6988 ** sqlite3_unlock_notify() method with the blocked connection handle as
6989 ** the first argument to register for a callback that will be invoked
6990 ** when the blocking connections current transaction is concluded. ^The
6991 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
6992 ** call that concludes the blocking connections transaction.
6994 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
6995 ** there is a chance that the blocking connection will have already
6996 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
6997 ** If this happens, then the specified callback is invoked immediately,
6998 ** from within the call to sqlite3_unlock_notify().)^
7000 ** ^If the blocked connection is attempting to obtain a write-lock on a
7001 ** shared-cache table, and more than one other connection currently holds
7002 ** a read-lock on the same table, then SQLite arbitrarily selects one of
7003 ** the other connections to use as the blocking connection.
7005 ** ^(There may be at most one unlock-notify callback registered by a
7006 ** blocked connection. If sqlite3_unlock_notify() is called when the
7007 ** blocked connection already has a registered unlock-notify callback,
7008 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
7009 ** called with a NULL pointer as its second argument, then any existing
7010 ** unlock-notify callback is canceled. ^The blocked connections
7011 ** unlock-notify callback may also be canceled by closing the blocked
7012 ** connection using [sqlite3_close()].
7014 ** The unlock-notify callback is not reentrant. If an application invokes
7015 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
7016 ** crash or deadlock may be the result.
7018 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
7019 ** returns SQLITE_OK.
7021 ** <b>Callback Invocation Details</b>
7023 ** When an unlock-notify callback is registered, the application provides a
7024 ** single void* pointer that is passed to the callback when it is invoked.
7025 ** However, the signature of the callback function allows SQLite to pass
7026 ** it an array of void* context pointers. The first argument passed to
7027 ** an unlock-notify callback is a pointer to an array of void* pointers,
7028 ** and the second is the number of entries in the array.
7030 ** When a blocking connections transaction is concluded, there may be
7031 ** more than one blocked connection that has registered for an unlock-notify
7032 ** callback. ^If two or more such blocked connections have specified the
7033 ** same callback function, then instead of invoking the callback function
7034 ** multiple times, it is invoked once with the set of void* context pointers
7035 ** specified by the blocked connections bundled together into an array.
7036 ** This gives the application an opportunity to prioritize any actions
7037 ** related to the set of unblocked database connections.
7039 ** <b>Deadlock Detection</b>
7041 ** Assuming that after registering for an unlock-notify callback a
7042 ** database waits for the callback to be issued before taking any further
7043 ** action (a reasonable assumption), then using this API may cause the
7044 ** application to deadlock. For example, if connection X is waiting for
7045 ** connection Y's transaction to be concluded, and similarly connection
7046 ** Y is waiting on connection X's transaction, then neither connection
7047 ** will proceed and the system may remain deadlocked indefinitely.
7049 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
7050 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
7051 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
7052 ** unlock-notify callback is registered. The system is said to be in
7053 ** a deadlocked state if connection A has registered for an unlock-notify
7054 ** callback on the conclusion of connection B's transaction, and connection
7055 ** B has itself registered for an unlock-notify callback when connection
7056 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
7057 ** the system is also considered to be deadlocked if connection B has
7058 ** registered for an unlock-notify callback on the conclusion of connection
7059 ** C's transaction, where connection C is waiting on connection A. ^Any
7060 ** number of levels of indirection are allowed.
7062 ** <b>The "DROP TABLE" Exception</b>
7064 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
7065 ** always appropriate to call sqlite3_unlock_notify(). There is however,
7066 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
7067 ** SQLite checks if there are any currently executing SELECT statements
7068 ** that belong to the same connection. If there are, SQLITE_LOCKED is
7069 ** returned. In this case there is no "blocking connection", so invoking
7070 ** sqlite3_unlock_notify() results in the unlock-notify callback being
7071 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
7072 ** or "DROP INDEX" query, an infinite loop might be the result.
7074 ** One way around this problem is to check the extended error code returned
7075 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
7076 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
7077 ** the special "DROP TABLE/INDEX" case, the extended error code is just
7078 ** SQLITE_LOCKED.)^
7080 int sqlite3_unlock_notify(
7081 sqlite3 *pBlocked, /* Waiting connection */
7082 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
7083 void *pNotifyArg /* Argument to pass to xNotify */
7088 ** CAPI3REF: String Comparison
7090 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
7091 ** and extensions to compare the contents of two buffers containing UTF-8
7092 ** strings in a case-independent fashion, using the same definition of "case
7093 ** independence" that SQLite uses internally when comparing identifiers.
7095 int sqlite3_stricmp(const char *, const char *);
7096 int sqlite3_strnicmp(const char *, const char *, int);
7099 ** CAPI3REF: String Globbing
7101 ** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches
7102 ** the glob pattern P, and it returns non-zero if string X does not match
7103 ** the glob pattern P. ^The definition of glob pattern matching used in
7104 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
7105 ** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case
7106 ** sensitive.
7108 ** Note that this routine returns zero on a match and non-zero if the strings
7109 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
7111 int sqlite3_strglob(const char *zGlob, const char *zStr);
7114 ** CAPI3REF: Error Logging Interface
7116 ** ^The [sqlite3_log()] interface writes a message into the [error log]
7117 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
7118 ** ^If logging is enabled, the zFormat string and subsequent arguments are
7119 ** used with [sqlite3_snprintf()] to generate the final output string.
7121 ** The sqlite3_log() interface is intended for use by extensions such as
7122 ** virtual tables, collating functions, and SQL functions. While there is
7123 ** nothing to prevent an application from calling sqlite3_log(), doing so
7124 ** is considered bad form.
7126 ** The zFormat string must not be NULL.
7128 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
7129 ** will not use dynamically allocated memory. The log message is stored in
7130 ** a fixed-length buffer on the stack. If the log message is longer than
7131 ** a few hundred characters, it will be truncated to the length of the
7132 ** buffer.
7134 void sqlite3_log(int iErrCode, const char *zFormat, ...);
7137 ** CAPI3REF: Write-Ahead Log Commit Hook
7139 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
7140 ** will be invoked each time a database connection commits data to a
7141 ** [write-ahead log] (i.e. whenever a transaction is committed in
7142 ** [journal_mode | journal_mode=WAL mode]).
7144 ** ^The callback is invoked by SQLite after the commit has taken place and
7145 ** the associated write-lock on the database released, so the implementation
7146 ** may read, write or [checkpoint] the database as required.
7148 ** ^The first parameter passed to the callback function when it is invoked
7149 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
7150 ** registering the callback. ^The second is a copy of the database handle.
7151 ** ^The third parameter is the name of the database that was written to -
7152 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
7153 ** is the number of pages currently in the write-ahead log file,
7154 ** including those that were just committed.
7156 ** The callback function should normally return [SQLITE_OK]. ^If an error
7157 ** code is returned, that error will propagate back up through the
7158 ** SQLite code base to cause the statement that provoked the callback
7159 ** to report an error, though the commit will have still occurred. If the
7160 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
7161 ** that does not correspond to any valid SQLite error code, the results
7162 ** are undefined.
7164 ** A single database handle may have at most a single write-ahead log callback
7165 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
7166 ** previously registered write-ahead log callback. ^Note that the
7167 ** [sqlite3_wal_autocheckpoint()] interface and the
7168 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
7169 ** those overwrite any prior [sqlite3_wal_hook()] settings.
7171 void *sqlite3_wal_hook(
7172 sqlite3*,
7173 int(*)(void *,sqlite3*,const char*,int),
7174 void*
7178 ** CAPI3REF: Configure an auto-checkpoint
7180 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
7181 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
7182 ** to automatically [checkpoint]
7183 ** after committing a transaction if there are N or
7184 ** more frames in the [write-ahead log] file. ^Passing zero or
7185 ** a negative value as the nFrame parameter disables automatic
7186 ** checkpoints entirely.
7188 ** ^The callback registered by this function replaces any existing callback
7189 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
7190 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
7191 ** configured by this function.
7193 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
7194 ** from SQL.
7196 ** ^Checkpoints initiated by this mechanism are
7197 ** [sqlite3_wal_checkpoint_v2|PASSIVE].
7199 ** ^Every new [database connection] defaults to having the auto-checkpoint
7200 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
7201 ** pages. The use of this interface
7202 ** is only necessary if the default setting is found to be suboptimal
7203 ** for a particular application.
7205 int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
7208 ** CAPI3REF: Checkpoint a database
7210 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
7211 ** on [database connection] D to be [checkpointed]. ^If X is NULL or an
7212 ** empty string, then a checkpoint is run on all databases of
7213 ** connection D. ^If the database connection D is not in
7214 ** [WAL | write-ahead log mode] then this interface is a harmless no-op.
7215 ** ^The [sqlite3_wal_checkpoint(D,X)] interface initiates a
7216 ** [sqlite3_wal_checkpoint_v2|PASSIVE] checkpoint.
7217 ** Use the [sqlite3_wal_checkpoint_v2()] interface to get a FULL
7218 ** or RESET checkpoint.
7220 ** ^The [wal_checkpoint pragma] can be used to invoke this interface
7221 ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the
7222 ** [wal_autocheckpoint pragma] can be used to cause this interface to be
7223 ** run whenever the WAL reaches a certain size threshold.
7225 ** See also: [sqlite3_wal_checkpoint_v2()]
7227 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
7230 ** CAPI3REF: Checkpoint a database
7232 ** Run a checkpoint operation on WAL database zDb attached to database
7233 ** handle db. The specific operation is determined by the value of the
7234 ** eMode parameter:
7236 ** <dl>
7237 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
7238 ** Checkpoint as many frames as possible without waiting for any database
7239 ** readers or writers to finish. Sync the db file if all frames in the log
7240 ** are checkpointed. This mode is the same as calling
7241 ** sqlite3_wal_checkpoint(). The [sqlite3_busy_handler|busy-handler callback]
7242 ** is never invoked.
7244 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
7245 ** This mode blocks (it invokes the
7246 ** [sqlite3_busy_handler|busy-handler callback]) until there is no
7247 ** database writer and all readers are reading from the most recent database
7248 ** snapshot. It then checkpoints all frames in the log file and syncs the
7249 ** database file. This call blocks database writers while it is running,
7250 ** but not database readers.
7252 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
7253 ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after
7254 ** checkpointing the log file it blocks (calls the
7255 ** [sqlite3_busy_handler|busy-handler callback])
7256 ** until all readers are reading from the database file only. This ensures
7257 ** that the next client to write to the database file restarts the log file
7258 ** from the beginning. This call blocks database writers while it is running,
7259 ** but not database readers.
7260 ** </dl>
7262 ** If pnLog is not NULL, then *pnLog is set to the total number of frames in
7263 ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
7264 ** the total number of checkpointed frames (including any that were already
7265 ** checkpointed when this function is called). *pnLog and *pnCkpt may be
7266 ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
7267 ** If no values are available because of an error, they are both set to -1
7268 ** before returning to communicate this to the caller.
7270 ** All calls obtain an exclusive "checkpoint" lock on the database file. If
7271 ** any other process is running a checkpoint operation at the same time, the
7272 ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a
7273 ** busy-handler configured, it will not be invoked in this case.
7275 ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive
7276 ** "writer" lock on the database file. If the writer lock cannot be obtained
7277 ** immediately, and a busy-handler is configured, it is invoked and the writer
7278 ** lock retried until either the busy-handler returns 0 or the lock is
7279 ** successfully obtained. The busy-handler is also invoked while waiting for
7280 ** database readers as described above. If the busy-handler returns 0 before
7281 ** the writer lock is obtained or while waiting for database readers, the
7282 ** checkpoint operation proceeds from that point in the same way as
7283 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
7284 ** without blocking any further. SQLITE_BUSY is returned in this case.
7286 ** If parameter zDb is NULL or points to a zero length string, then the
7287 ** specified operation is attempted on all WAL databases. In this case the
7288 ** values written to output parameters *pnLog and *pnCkpt are undefined. If
7289 ** an SQLITE_BUSY error is encountered when processing one or more of the
7290 ** attached WAL databases, the operation is still attempted on any remaining
7291 ** attached databases and SQLITE_BUSY is returned to the caller. If any other
7292 ** error occurs while processing an attached database, processing is abandoned
7293 ** and the error code returned to the caller immediately. If no error
7294 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
7295 ** databases, SQLITE_OK is returned.
7297 ** If database zDb is the name of an attached database that is not in WAL
7298 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
7299 ** zDb is not NULL (or a zero length string) and is not the name of any
7300 ** attached database, SQLITE_ERROR is returned to the caller.
7302 int sqlite3_wal_checkpoint_v2(
7303 sqlite3 *db, /* Database handle */
7304 const char *zDb, /* Name of attached database (or NULL) */
7305 int eMode, /* SQLITE_CHECKPOINT_* value */
7306 int *pnLog, /* OUT: Size of WAL log in frames */
7307 int *pnCkpt /* OUT: Total number of frames checkpointed */
7311 ** CAPI3REF: Checkpoint operation parameters
7313 ** These constants can be used as the 3rd parameter to
7314 ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()]
7315 ** documentation for additional information about the meaning and use of
7316 ** each of these values.
7318 #define SQLITE_CHECKPOINT_PASSIVE 0
7319 #define SQLITE_CHECKPOINT_FULL 1
7320 #define SQLITE_CHECKPOINT_RESTART 2
7323 ** CAPI3REF: Virtual Table Interface Configuration
7325 ** This function may be called by either the [xConnect] or [xCreate] method
7326 ** of a [virtual table] implementation to configure
7327 ** various facets of the virtual table interface.
7329 ** If this interface is invoked outside the context of an xConnect or
7330 ** xCreate virtual table method then the behavior is undefined.
7332 ** At present, there is only one option that may be configured using
7333 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options
7334 ** may be added in the future.
7336 int sqlite3_vtab_config(sqlite3*, int op, ...);
7339 ** CAPI3REF: Virtual Table Configuration Options
7341 ** These macros define the various options to the
7342 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
7343 ** can use to customize and optimize their behavior.
7345 ** <dl>
7346 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
7347 ** <dd>Calls of the form
7348 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
7349 ** where X is an integer. If X is zero, then the [virtual table] whose
7350 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
7351 ** support constraints. In this configuration (which is the default) if
7352 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
7353 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
7354 ** specified as part of the users SQL statement, regardless of the actual
7355 ** ON CONFLICT mode specified.
7357 ** If X is non-zero, then the virtual table implementation guarantees
7358 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
7359 ** any modifications to internal or persistent data structures have been made.
7360 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
7361 ** is able to roll back a statement or database transaction, and abandon
7362 ** or continue processing the current SQL statement as appropriate.
7363 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
7364 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
7365 ** had been ABORT.
7367 ** Virtual table implementations that are required to handle OR REPLACE
7368 ** must do so within the [xUpdate] method. If a call to the
7369 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
7370 ** CONFLICT policy is REPLACE, the virtual table implementation should
7371 ** silently replace the appropriate rows within the xUpdate callback and
7372 ** return SQLITE_OK. Or, if this is not possible, it may return
7373 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
7374 ** constraint handling.
7375 ** </dl>
7377 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
7380 ** CAPI3REF: Determine The Virtual Table Conflict Policy
7382 ** This function may only be called from within a call to the [xUpdate] method
7383 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
7384 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
7385 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
7386 ** of the SQL statement that triggered the call to the [xUpdate] method of the
7387 ** [virtual table].
7389 int sqlite3_vtab_on_conflict(sqlite3 *);
7392 ** CAPI3REF: Conflict resolution modes
7393 ** KEYWORDS: {conflict resolution mode}
7395 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
7396 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
7397 ** is for the SQL statement being evaluated.
7399 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
7400 ** return value from the [sqlite3_set_authorizer()] callback and that
7401 ** [SQLITE_ABORT] is also a [result code].
7403 #define SQLITE_ROLLBACK 1
7404 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
7405 #define SQLITE_FAIL 3
7406 /* #define SQLITE_ABORT 4 // Also an error code */
7407 #define SQLITE_REPLACE 5
7412 ** Undo the hack that converts floating point types to integer for
7413 ** builds on processors without floating point support.
7415 #ifdef SQLITE_OMIT_FLOATING_POINT
7416 # undef double
7417 #endif
7419 #ifdef __cplusplus
7420 } /* End of the 'extern "C"' block */
7421 #endif
7422 #endif /* _SQLITE3_H_ */