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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.
10 **
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.
17 **
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.
23 **
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.
27 **
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.
32 */
33 #ifndef _SQLITE3_H_
34 #define _SQLITE3_H_
37 /*
38 ** Make sure we can call this stuff from C++.
39 */
40 #ifdef __cplusplus
42 #endif
45 /*
46 ** Add the ability to override 'extern'
47 */
48 #ifndef SQLITE_EXTERN
49 # define SQLITE_EXTERN extern
50 #endif
52 /*
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.
58 **
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.
64 */
65 #define SQLITE_DEPRECATED
66 #define SQLITE_EXPERIMENTAL
68 /*
69 ** Ensure these symbols were not defined by some previous header file.
70 */
71 #ifdef SQLITE_VERSION
72 # undef SQLITE_VERSION
73 #endif
74 #ifdef SQLITE_VERSION_NUMBER
75 # undef SQLITE_VERSION_NUMBER
76 #endif
78 /*
79 ** CAPI3REF: Compile-Time Library Version Numbers
80 **
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.
92 **
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.
100 **
101 ** See also: [sqlite3_libversion()],
102 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
103 ** [sqlite_version()] and [sqlite_source_id()].
104 */
106 #define SQLITE_VERSION_NUMBER --VERSION-NUMBER--
109 /*
110 ** CAPI3REF: Run-Time Library Version Numbers
111 ** KEYWORDS: sqlite3_version, sqlite3_sourceid
112 **
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.
120 **
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>)^
126 **
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.
136 **
137 ** See also: [sqlite_version()] and [sqlite_source_id()].
138 */
144 /*
145 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
146 **
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().
151 **
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().
158 **
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.
162 **
163 ** See also: SQL functions [sqlite_compileoption_used()] and
164 ** [sqlite_compileoption_get()] and the [compile_options pragma].
165 */
166 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
169 #endif
171 /*
172 ** CAPI3REF: Test To See If The Library Is Threadsafe
173 **
174 ** ^The sqlite3_threadsafe() function returns zero if and only if
175 ** SQLite was compiled mutexing code omitted due to the
176 ** [SQLITE_THREADSAFE] compile-time option being set to 0.
177 **
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.
184 **
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.
189 **
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.
193 **
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().)^
204 **
205 ** See the [threading mode] documentation for additional information.
206 */
209 /*
210 ** CAPI3REF: Database Connection Handle
211 ** KEYWORDS: {database connection} {database connections}
212 **
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 ** is its destructor. There are many other interfaces (such as
218 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
219 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
220 ** sqlite3 object.
221 */
224 /*
225 ** CAPI3REF: 64-Bit Integer Types
226 ** KEYWORDS: sqlite_int64 sqlite_uint64
227 **
228 ** Because there is no cross-platform way to specify 64-bit integer types
229 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
230 **
231 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
232 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
233 ** compatibility only.
234 **
235 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
236 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
237 ** sqlite3_uint64 and sqlite_uint64 types can store integer values
238 ** between 0 and +18446744073709551615 inclusive.
239 */
240 #ifdef SQLITE_INT64_TYPE
243 #elif defined(_MSC_VER) || defined(__BORLANDC__)
246 #else
249 #endif
253 /*
254 ** If compiling for a processor that lacks floating point support,
255 ** substitute integer for floating-point.
256 */
257 #ifdef SQLITE_OMIT_FLOATING_POINT
258 # define double sqlite3_int64
259 #endif
261 /*
262 ** CAPI3REF: Closing A Database Connection
263 **
264 ** ^The sqlite3_close() routine is the destructor for the [sqlite3] object.
265 ** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is
266 ** successfully destroyed and all associated resources are deallocated.
267 **
268 ** Applications must [sqlite3_finalize | finalize] all [prepared statements]
269 ** and [sqlite3_blob_close | close] all [BLOB handles] associated with
270 ** the [sqlite3] object prior to attempting to close the object. ^If
271 ** sqlite3_close() is called on a [database connection] that still has
272 ** outstanding [prepared statements] or [BLOB handles], then it returns
273 ** SQLITE_BUSY.
274 **
275 ** ^If [sqlite3_close()] is invoked while a transaction is open,
276 ** the transaction is automatically rolled back.
277 **
278 ** The C parameter to [sqlite3_close(C)] must be either a NULL
279 ** pointer or an [sqlite3] object pointer obtained
280 ** from [sqlite3_open()], [sqlite3_open16()], or
281 ** [sqlite3_open_v2()], and not previously closed.
282 ** ^Calling sqlite3_close() with a NULL pointer argument is a
283 ** harmless no-op.
284 */
287 /*
288 ** The type for a callback function.
289 ** This is legacy and deprecated. It is included for historical
290 ** compatibility and is not documented.
291 */
294 /*
295 ** CAPI3REF: One-Step Query Execution Interface
296 **
297 ** The sqlite3_exec() interface is a convenience wrapper around
298 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
299 ** that allows an application to run multiple statements of SQL
300 ** without having to use a lot of C code.
301 **
302 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
303 ** semicolon-separate SQL statements passed into its 2nd argument,
304 ** in the context of the [database connection] passed in as its 1st
305 ** argument. ^If the callback function of the 3rd argument to
306 ** sqlite3_exec() is not NULL, then it is invoked for each result row
307 ** coming out of the evaluated SQL statements. ^The 4th argument to
308 ** to sqlite3_exec() is relayed through to the 1st argument of each
309 ** callback invocation. ^If the callback pointer to sqlite3_exec()
310 ** is NULL, then no callback is ever invoked and result rows are
311 ** ignored.
312 **
313 ** ^If an error occurs while evaluating the SQL statements passed into
314 ** sqlite3_exec(), then execution of the current statement stops and
315 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
316 ** is not NULL then any error message is written into memory obtained
317 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
318 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
319 ** on error message strings returned through the 5th parameter of
320 ** of sqlite3_exec() after the error message string is no longer needed.
321 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
322 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
323 ** NULL before returning.
324 **
325 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
326 ** routine returns SQLITE_ABORT without invoking the callback again and
327 ** without running any subsequent SQL statements.
328 **
329 ** ^The 2nd argument to the sqlite3_exec() callback function is the
330 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
331 ** callback is an array of pointers to strings obtained as if from
332 ** [sqlite3_column_text()], one for each column. ^If an element of a
333 ** result row is NULL then the corresponding string pointer for the
334 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
335 ** sqlite3_exec() callback is an array of pointers to strings where each
336 ** entry represents the name of corresponding result column as obtained
337 ** from [sqlite3_column_name()].
338 **
339 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
340 ** to an empty string, or a pointer that contains only whitespace and/or
341 ** SQL comments, then no SQL statements are evaluated and the database
342 ** is not changed.
343 **
344 ** Restrictions:
345 **
346 ** <ul>
347 ** <li> The application must insure that the 1st parameter to sqlite3_exec()
348 ** is a valid and open [database connection].
349 ** <li> The application must not close [database connection] specified by
350 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
351 ** <li> The application must not modify the SQL statement text passed into
352 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
353 ** </ul>
354 */
361 );
363 /*
364 ** CAPI3REF: Result Codes
365 ** KEYWORDS: SQLITE_OK {error code} {error codes}
366 ** KEYWORDS: {result code} {result codes}
367 **
368 ** Many SQLite functions return an integer result code from the set shown
369 ** here in order to indicates success or failure.
370 **
371 ** New error codes may be added in future versions of SQLite.
372 **
373 ** See also: [SQLITE_IOERR_READ | extended result codes]
374 */
376 /* beginning-of-error-codes */
405 /* end-of-error-codes */
407 /*
408 ** CAPI3REF: Extended Result Codes
409 ** KEYWORDS: {extended error code} {extended error codes}
410 ** KEYWORDS: {extended result code} {extended result codes}
411 **
412 ** In its default configuration, SQLite API routines return one of 26 integer
413 ** [SQLITE_OK | result codes]. However, experience has shown that many of
414 ** these result codes are too coarse-grained. They do not provide as
415 ** much information about problems as programmers might like. In an effort to
416 ** address this, newer versions of SQLite (version 3.3.8 and later) include
417 ** support for additional result codes that provide more detailed information
418 ** about errors. The extended result codes are enabled or disabled
419 ** on a per database connection basis using the
420 ** [sqlite3_extended_result_codes()] API.
421 **
422 ** Some of the available extended result codes are listed here.
423 ** One may expect the number of extended result codes will be expand
424 ** over time. Software that uses extended result codes should expect
425 ** to see new result codes in future releases of SQLite.
426 **
427 ** The SQLITE_OK result code will never be extended. It will always
428 ** be exactly zero.
429 */
430 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
431 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
432 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
433 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
434 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
435 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
436 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
437 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
438 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
439 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
440 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
441 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
442 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
443 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
444 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
445 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
446 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
447 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
448 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
449 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
450 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
451 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
452 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
454 /*
455 ** CAPI3REF: Flags For File Open Operations
456 **
457 ** These bit values are intended for use in the
458 ** 3rd parameter to the [sqlite3_open_v2()] interface and
459 ** in the 4th parameter to the xOpen method of the
460 ** [sqlite3_vfs] object.
461 */
481 /* Reserved: 0x00F00000 */
483 /*
484 ** CAPI3REF: Device Characteristics
485 **
486 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
487 ** object returns an integer which is a vector of the these
488 ** bit values expressing I/O characteristics of the mass storage
489 ** device that holds the file that the [sqlite3_io_methods]
490 ** refers to.
491 **
492 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
493 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
494 ** mean that writes of blocks that are nnn bytes in size and
495 ** are aligned to an address which is an integer multiple of
496 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
497 ** that when data is appended to a file, the data is appended
498 ** first then the size of the file is extended, never the other
499 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
500 ** information is written to disk in the same order as calls
501 ** to xWrite().
502 */
503 #define SQLITE_IOCAP_ATOMIC 0x00000001
504 #define SQLITE_IOCAP_ATOMIC512 0x00000002
505 #define SQLITE_IOCAP_ATOMIC1K 0x00000004
506 #define SQLITE_IOCAP_ATOMIC2K 0x00000008
507 #define SQLITE_IOCAP_ATOMIC4K 0x00000010
508 #define SQLITE_IOCAP_ATOMIC8K 0x00000020
509 #define SQLITE_IOCAP_ATOMIC16K 0x00000040
510 #define SQLITE_IOCAP_ATOMIC32K 0x00000080
511 #define SQLITE_IOCAP_ATOMIC64K 0x00000100
512 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
513 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
514 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
516 /*
517 ** CAPI3REF: File Locking Levels
518 **
519 ** SQLite uses one of these integer values as the second
520 ** argument to calls it makes to the xLock() and xUnlock() methods
521 ** of an [sqlite3_io_methods] object.
522 */
523 #define SQLITE_LOCK_NONE 0
524 #define SQLITE_LOCK_SHARED 1
525 #define SQLITE_LOCK_RESERVED 2
526 #define SQLITE_LOCK_PENDING 3
527 #define SQLITE_LOCK_EXCLUSIVE 4
529 /*
530 ** CAPI3REF: Synchronization Type Flags
531 **
532 ** When SQLite invokes the xSync() method of an
533 ** [sqlite3_io_methods] object it uses a combination of
534 ** these integer values as the second argument.
535 **
536 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
537 ** sync operation only needs to flush data to mass storage. Inode
538 ** information need not be flushed. If the lower four bits of the flag
539 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
540 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
541 ** to use Mac OS X style fullsync instead of fsync().
542 **
543 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
544 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
545 ** settings. The [synchronous pragma] determines when calls to the
546 ** xSync VFS method occur and applies uniformly across all platforms.
547 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
548 ** energetic or rigorous or forceful the sync operations are and
549 ** only make a difference on Mac OSX for the default SQLite code.
550 ** (Third-party VFS implementations might also make the distinction
551 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
552 ** operating systems natively supported by SQLite, only Mac OSX
553 ** cares about the difference.)
554 */
555 #define SQLITE_SYNC_NORMAL 0x00002
556 #define SQLITE_SYNC_FULL 0x00003
557 #define SQLITE_SYNC_DATAONLY 0x00010
559 /*
560 ** CAPI3REF: OS Interface Open File Handle
561 **
562 ** An [sqlite3_file] object represents an open file in the
563 ** [sqlite3_vfs | OS interface layer]. Individual OS interface
564 ** implementations will
565 ** want to subclass this object by appending additional fields
566 ** for their own use. The pMethods entry is a pointer to an
567 ** [sqlite3_io_methods] object that defines methods for performing
568 ** I/O operations on the open file.
569 */
573 };
575 /*
576 ** CAPI3REF: OS Interface File Virtual Methods Object
577 **
578 ** Every file opened by the [sqlite3_vfs] xOpen method populates an
579 ** [sqlite3_file] object (or, more commonly, a subclass of the
580 ** [sqlite3_file] object) with a pointer to an instance of this object.
581 ** This object defines the methods used to perform various operations
582 ** against the open file represented by the [sqlite3_file] object.
583 **
584 ** If the xOpen method sets the sqlite3_file.pMethods element
585 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
586 ** may be invoked even if the xOpen reported that it failed. The
587 ** only way to prevent a call to xClose following a failed xOpen
588 ** is for the xOpen to set the sqlite3_file.pMethods element to NULL.
589 **
590 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
591 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
592 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
593 ** flag may be ORed in to indicate that only the data of the file
594 ** and not its inode needs to be synced.
595 **
596 ** The integer values to xLock() and xUnlock() are one of
597 ** <ul>
598 ** <li> [SQLITE_LOCK_NONE],
599 ** <li> [SQLITE_LOCK_SHARED],
600 ** <li> [SQLITE_LOCK_RESERVED],
601 ** <li> [SQLITE_LOCK_PENDING], or
602 ** <li> [SQLITE_LOCK_EXCLUSIVE].
603 ** </ul>
604 ** xLock() increases the lock. xUnlock() decreases the lock.
605 ** The xCheckReservedLock() method checks whether any database connection,
606 ** either in this process or in some other process, is holding a RESERVED,
607 ** PENDING, or EXCLUSIVE lock on the file. It returns true
608 ** if such a lock exists and false otherwise.
609 **
610 ** The xFileControl() method is a generic interface that allows custom
611 ** VFS implementations to directly control an open file using the
612 ** [sqlite3_file_control()] interface. The second "op" argument is an
613 ** integer opcode. The third argument is a generic pointer intended to
614 ** point to a structure that may contain arguments or space in which to
615 ** write return values. Potential uses for xFileControl() might be
616 ** functions to enable blocking locks with timeouts, to change the
617 ** locking strategy (for example to use dot-file locks), to inquire
618 ** about the status of a lock, or to break stale locks. The SQLite
619 ** core reserves all opcodes less than 100 for its own use.
620 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
621 ** Applications that define a custom xFileControl method should use opcodes
622 ** greater than 100 to avoid conflicts. VFS implementations should
623 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
624 ** recognize.
625 **
626 ** The xSectorSize() method returns the sector size of the
627 ** device that underlies the file. The sector size is the
628 ** minimum write that can be performed without disturbing
629 ** other bytes in the file. The xDeviceCharacteristics()
630 ** method returns a bit vector describing behaviors of the
631 ** underlying device:
632 **
633 ** <ul>
634 ** <li> [SQLITE_IOCAP_ATOMIC]
635 ** <li> [SQLITE_IOCAP_ATOMIC512]
636 ** <li> [SQLITE_IOCAP_ATOMIC1K]
637 ** <li> [SQLITE_IOCAP_ATOMIC2K]
638 ** <li> [SQLITE_IOCAP_ATOMIC4K]
639 ** <li> [SQLITE_IOCAP_ATOMIC8K]
640 ** <li> [SQLITE_IOCAP_ATOMIC16K]
641 ** <li> [SQLITE_IOCAP_ATOMIC32K]
642 ** <li> [SQLITE_IOCAP_ATOMIC64K]
643 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
644 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
645 ** </ul>
646 **
647 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
648 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
649 ** mean that writes of blocks that are nnn bytes in size and
650 ** are aligned to an address which is an integer multiple of
651 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
652 ** that when data is appended to a file, the data is appended
653 ** first then the size of the file is extended, never the other
654 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
655 ** information is written to disk in the same order as calls
656 ** to xWrite().
657 **
658 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
659 ** in the unread portions of the buffer with zeros. A VFS that
660 ** fails to zero-fill short reads might seem to work. However,
661 ** failure to zero-fill short reads will eventually lead to
662 ** database corruption.
663 */
679 /* Methods above are valid for version 1 */
684 /* Methods above are valid for version 2 */
685 /* Additional methods may be added in future releases */
686 };
688 /*
689 ** CAPI3REF: Standard File Control Opcodes
690 **
691 ** These integer constants are opcodes for the xFileControl method
692 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
693 ** interface.
694 **
695 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
696 ** opcode causes the xFileControl method to write the current state of
697 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
698 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
699 ** into an integer that the pArg argument points to. This capability
700 ** is used during testing and only needs to be supported when SQLITE_TEST
701 ** is defined.
702 **
703 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
704 ** layer a hint of how large the database file will grow to be during the
705 ** current transaction. This hint is not guaranteed to be accurate but it
706 ** is often close. The underlying VFS might choose to preallocate database
707 ** file space based on this hint in order to help writes to the database
708 ** file run faster.
709 **
710 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
711 ** extends and truncates the database file in chunks of a size specified
712 ** by the user. The fourth argument to [sqlite3_file_control()] should
713 ** point to an integer (type int) containing the new chunk-size to use
714 ** for the nominated database. Allocating database file space in large
715 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
716 ** improve performance on some systems.
717 **
718 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
719 ** to the [sqlite3_file] object associated with a particular database
720 ** connection. See the [sqlite3_file_control()] documentation for
721 ** additional information.
722 **
723 ** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by
724 ** SQLite and sent to all VFSes in place of a call to the xSync method
725 ** when the database connection has [PRAGMA synchronous] set to OFF.)^
726 ** Some specialized VFSes need this signal in order to operate correctly
727 ** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most
728 ** VFSes do not need this signal and should silently ignore this opcode.
729 ** Applications should not call [sqlite3_file_control()] with this
730 ** opcode as doing so may disrupt the operation of the specialized VFSes
731 ** that do require it.
732 */
733 #define SQLITE_FCNTL_LOCKSTATE 1
734 #define SQLITE_GET_LOCKPROXYFILE 2
735 #define SQLITE_SET_LOCKPROXYFILE 3
736 #define SQLITE_LAST_ERRNO 4
737 #define SQLITE_FCNTL_SIZE_HINT 5
738 #define SQLITE_FCNTL_CHUNK_SIZE 6
739 #define SQLITE_FCNTL_FILE_POINTER 7
740 #define SQLITE_FCNTL_SYNC_OMITTED 8
743 /*
744 ** CAPI3REF: Mutex Handle
745 **
746 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
747 ** abstract type for a mutex object. The SQLite core never looks
748 ** at the internal representation of an [sqlite3_mutex]. It only
749 ** deals with pointers to the [sqlite3_mutex] object.
750 **
751 ** Mutexes are created using [sqlite3_mutex_alloc()].
752 */
755 /*
756 ** CAPI3REF: OS Interface Object
757 **
758 ** An instance of the sqlite3_vfs object defines the interface between
759 ** the SQLite core and the underlying operating system. The "vfs"
760 ** in the name of the object stands for "virtual file system".
761 **
762 ** The value of the iVersion field is initially 1 but may be larger in
763 ** future versions of SQLite. Additional fields may be appended to this
764 ** object when the iVersion value is increased. Note that the structure
765 ** of the sqlite3_vfs object changes in the transaction between
766 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
767 ** modified.
768 **
769 ** The szOsFile field is the size of the subclassed [sqlite3_file]
770 ** structure used by this VFS. mxPathname is the maximum length of
771 ** a pathname in this VFS.
772 **
773 ** Registered sqlite3_vfs objects are kept on a linked list formed by
774 ** the pNext pointer. The [sqlite3_vfs_register()]
775 ** and [sqlite3_vfs_unregister()] interfaces manage this list
776 ** in a thread-safe way. The [sqlite3_vfs_find()] interface
777 ** searches the list. Neither the application code nor the VFS
778 ** implementation should use the pNext pointer.
779 **
780 ** The pNext field is the only field in the sqlite3_vfs
781 ** structure that SQLite will ever modify. SQLite will only access
782 ** or modify this field while holding a particular static mutex.
783 ** The application should never modify anything within the sqlite3_vfs
784 ** object once the object has been registered.
785 **
786 ** The zName field holds the name of the VFS module. The name must
787 ** be unique across all VFS modules.
788 **
789 ** ^SQLite guarantees that the zFilename parameter to xOpen
790 ** is either a NULL pointer or string obtained
791 ** from xFullPathname() with an optional suffix added.
792 ** ^If a suffix is added to the zFilename parameter, it will
793 ** consist of a single "-" character followed by no more than
794 ** 10 alphanumeric and/or "-" characters.
795 ** ^SQLite further guarantees that
796 ** the string will be valid and unchanged until xClose() is
797 ** called. Because of the previous sentence,
798 ** the [sqlite3_file] can safely store a pointer to the
799 ** filename if it needs to remember the filename for some reason.
800 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
801 ** must invent its own temporary name for the file. ^Whenever the
802 ** xFilename parameter is NULL it will also be the case that the
803 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
804 **
805 ** The flags argument to xOpen() includes all bits set in
806 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
807 ** or [sqlite3_open16()] is used, then flags includes at least
808 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
809 ** If xOpen() opens a file read-only then it sets *pOutFlags to
810 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
811 **
812 ** ^(SQLite will also add one of the following flags to the xOpen()
813 ** call, depending on the object being opened:
814 **
815 ** <ul>
816 ** <li> [SQLITE_OPEN_MAIN_DB]
817 ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
818 ** <li> [SQLITE_OPEN_TEMP_DB]
819 ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
820 ** <li> [SQLITE_OPEN_TRANSIENT_DB]
821 ** <li> [SQLITE_OPEN_SUBJOURNAL]
822 ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
823 ** <li> [SQLITE_OPEN_WAL]
824 ** </ul>)^
825 **
826 ** The file I/O implementation can use the object type flags to
827 ** change the way it deals with files. For example, an application
828 ** that does not care about crash recovery or rollback might make
829 ** the open of a journal file a no-op. Writes to this journal would
830 ** also be no-ops, and any attempt to read the journal would return
831 ** SQLITE_IOERR. Or the implementation might recognize that a database
832 ** file will be doing page-aligned sector reads and writes in a random
833 ** order and set up its I/O subsystem accordingly.
834 **
835 ** SQLite might also add one of the following flags to the xOpen method:
836 **
837 ** <ul>
838 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
839 ** <li> [SQLITE_OPEN_EXCLUSIVE]
840 ** </ul>
841 **
842 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
843 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
844 ** will be set for TEMP databases and their journals, transient
845 ** databases, and subjournals.
846 **
847 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
848 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
849 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
850 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
851 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
852 ** be created, and that it is an error if it already exists.
853 ** It is <i>not</i> used to indicate the file should be opened
854 ** for exclusive access.
855 **
856 ** ^At least szOsFile bytes of memory are allocated by SQLite
857 ** to hold the [sqlite3_file] structure passed as the third
858 ** argument to xOpen. The xOpen method does not have to
859 ** allocate the structure; it should just fill it in. Note that
860 ** the xOpen method must set the sqlite3_file.pMethods to either
861 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
862 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
863 ** element will be valid after xOpen returns regardless of the success
864 ** or failure of the xOpen call.
865 **
866 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
867 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
868 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
869 ** to test whether a file is at least readable. The file can be a
870 ** directory.
871 **
872 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
873 ** output buffer xFullPathname. The exact size of the output buffer
874 ** is also passed as a parameter to both methods. If the output buffer
875 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
876 ** handled as a fatal error by SQLite, vfs implementations should endeavor
877 ** to prevent this by setting mxPathname to a sufficiently large value.
878 **
879 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
880 ** interfaces are not strictly a part of the filesystem, but they are
881 ** included in the VFS structure for completeness.
882 ** The xRandomness() function attempts to return nBytes bytes
883 ** of good-quality randomness into zOut. The return value is
884 ** the actual number of bytes of randomness obtained.
885 ** The xSleep() method causes the calling thread to sleep for at
886 ** least the number of microseconds given. ^The xCurrentTime()
887 ** method returns a Julian Day Number for the current date and time as
888 ** a floating point value.
889 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
890 ** Day Number multipled by 86400000 (the number of milliseconds in
891 ** a 24-hour day).
892 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
893 ** date and time if that method is available (if iVersion is 2 or
894 ** greater and the function pointer is not NULL) and will fall back
895 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
896 **
897 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
898 ** are not used by the SQLite core. These optional interfaces are provided
899 ** by some VFSes to facilitate testing of the VFS code. By overriding
900 ** system calls with functions under its control, a test program can
901 ** simulate faults and error conditions that would otherwise be difficult
902 ** or impossible to induce. The set of system calls that can be overridden
903 ** varies from one VFS to another, and from one version of the same VFS to the
904 ** next. Applications that use these interfaces must be prepared for any
905 ** or all of these interfaces to be NULL or for their behavior to change
906 ** from one release to the next. Applications must not attempt to access
907 ** any of these methods if the iVersion of the VFS is less than 3.
908 */
931 /*
932 ** The methods above are in version 1 of the sqlite_vfs object
933 ** definition. Those that follow are added in version 2 or later
934 */
936 /*
937 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
938 ** Those below are for version 3 and greater.
939 */
943 /*
944 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
945 ** New fields may be appended in figure versions. The iVersion
946 ** value will increment whenever this happens.
947 */
948 };
950 /*
951 ** CAPI3REF: Flags for the xAccess VFS method
952 **
953 ** These integer constants can be used as the third parameter to
954 ** the xAccess method of an [sqlite3_vfs] object. They determine
955 ** what kind of permissions the xAccess method is looking for.
956 ** With SQLITE_ACCESS_EXISTS, the xAccess method
957 ** simply checks whether the file exists.
958 ** With SQLITE_ACCESS_READWRITE, the xAccess method
959 ** checks whether the named directory is both readable and writable
960 ** (in other words, if files can be added, removed, and renamed within
961 ** the directory).
962 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
963 ** [temp_store_directory pragma], though this could change in a future
964 ** release of SQLite.
965 ** With SQLITE_ACCESS_READ, the xAccess method
966 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
967 ** currently unused, though it might be used in a future release of
968 ** SQLite.
969 */
970 #define SQLITE_ACCESS_EXISTS 0
974 /*
975 ** CAPI3REF: Flags for the xShmLock VFS method
976 **
977 ** These integer constants define the various locking operations
978 ** allowed by the xShmLock method of [sqlite3_io_methods]. The
979 ** following are the only legal combinations of flags to the
980 ** xShmLock method:
981 **
982 ** <ul>
983 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
984 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
985 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
986 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
987 ** </ul>
988 **
989 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
990 ** was given no the corresponding lock.
991 **
992 ** The xShmLock method can transition between unlocked and SHARED or
993 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
994 ** and EXCLUSIVE.
995 */
996 #define SQLITE_SHM_UNLOCK 1
997 #define SQLITE_SHM_LOCK 2
998 #define SQLITE_SHM_SHARED 4
999 #define SQLITE_SHM_EXCLUSIVE 8
1001 /*
1002 ** CAPI3REF: Maximum xShmLock index
1003 **
1004 ** The xShmLock method on [sqlite3_io_methods] may use values
1005 ** between 0 and this upper bound as its "offset" argument.
1006 ** The SQLite core will never attempt to acquire or release a
1007 ** lock outside of this range
1008 */
1009 #define SQLITE_SHM_NLOCK 8
1012 /*
1013 ** CAPI3REF: Initialize The SQLite Library
1014 **
1015 ** ^The sqlite3_initialize() routine initializes the
1016 ** SQLite library. ^The sqlite3_shutdown() routine
1017 ** deallocates any resources that were allocated by sqlite3_initialize().
1018 ** These routines are designed to aid in process initialization and
1019 ** shutdown on embedded systems. Workstation applications using
1020 ** SQLite normally do not need to invoke either of these routines.
1021 **
1022 ** A call to sqlite3_initialize() is an "effective" call if it is
1023 ** the first time sqlite3_initialize() is invoked during the lifetime of
1024 ** the process, or if it is the first time sqlite3_initialize() is invoked
1025 ** following a call to sqlite3_shutdown(). ^(Only an effective call
1026 ** of sqlite3_initialize() does any initialization. All other calls
1027 ** are harmless no-ops.)^
1028 **
1029 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1030 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1031 ** an effective call to sqlite3_shutdown() does any deinitialization.
1032 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1033 **
1034 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1035 ** is not. The sqlite3_shutdown() interface must only be called from a
1036 ** single thread. All open [database connections] must be closed and all
1037 ** other SQLite resources must be deallocated prior to invoking
1038 ** sqlite3_shutdown().
1039 **
1040 ** Among other things, ^sqlite3_initialize() will invoke
1041 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1042 ** will invoke sqlite3_os_end().
1043 **
1044 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1045 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1046 ** the library (perhaps it is unable to allocate a needed resource such
1047 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1048 **
1049 ** ^The sqlite3_initialize() routine is called internally by many other
1050 ** SQLite interfaces so that an application usually does not need to
1051 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1052 ** calls sqlite3_initialize() so the SQLite library will be automatically
1053 ** initialized when [sqlite3_open()] is called if it has not be initialized
1054 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1055 ** compile-time option, then the automatic calls to sqlite3_initialize()
1056 ** are omitted and the application must call sqlite3_initialize() directly
1057 ** prior to using any other SQLite interface. For maximum portability,
1058 ** it is recommended that applications always invoke sqlite3_initialize()
1059 ** directly prior to using any other SQLite interface. Future releases
1060 ** of SQLite may require this. In other words, the behavior exhibited
1061 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1062 ** default behavior in some future release of SQLite.
1063 **
1064 ** The sqlite3_os_init() routine does operating-system specific
1065 ** initialization of the SQLite library. The sqlite3_os_end()
1066 ** routine undoes the effect of sqlite3_os_init(). Typical tasks
1067 ** performed by these routines include allocation or deallocation
1068 ** of static resources, initialization of global variables,
1069 ** setting up a default [sqlite3_vfs] module, or setting up
1070 ** a default configuration using [sqlite3_config()].
1071 **
1072 ** The application should never invoke either sqlite3_os_init()
1073 ** or sqlite3_os_end() directly. The application should only invoke
1074 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1075 ** interface is called automatically by sqlite3_initialize() and
1076 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1077 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1078 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1079 ** When [custom builds | built for other platforms]
1080 ** (using the [SQLITE_OS_OTHER=1] compile-time
1081 ** option) the application must supply a suitable implementation for
1082 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1083 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1084 ** must return [SQLITE_OK] on success and some other [error code] upon
1085 ** failure.
1086 */
1092 /*
1093 ** CAPI3REF: Configuring The SQLite Library
1094 **
1095 ** The sqlite3_config() interface is used to make global configuration
1096 ** changes to SQLite in order to tune SQLite to the specific needs of
1097 ** the application. The default configuration is recommended for most
1098 ** applications and so this routine is usually not necessary. It is
1099 ** provided to support rare applications with unusual needs.
1100 **
1101 ** The sqlite3_config() interface is not threadsafe. The application
1102 ** must insure that no other SQLite interfaces are invoked by other
1103 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config()
1104 ** may only be invoked prior to library initialization using
1105 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1106 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1107 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1108 ** Note, however, that ^sqlite3_config() can be called as part of the
1109 ** implementation of an application-defined [sqlite3_os_init()].
1110 **
1111 ** The first argument to sqlite3_config() is an integer
1112 ** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines
1113 ** what property of SQLite is to be configured. Subsequent arguments
1114 ** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option]
1115 ** in the first argument.
1116 **
1117 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1118 ** ^If the option is unknown or SQLite is unable to set the option
1119 ** then this routine returns a non-zero [error code].
1120 */
1123 /*
1124 ** CAPI3REF: Configure database connections
1125 **
1126 ** The sqlite3_db_config() interface is used to make configuration
1127 ** changes to a [database connection]. The interface is similar to
1128 ** [sqlite3_config()] except that the changes apply to a single
1129 ** [database connection] (specified in the first argument).
1130 **
1131 ** The second argument to sqlite3_db_config(D,V,...) is the
1132 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1133 ** that indicates what aspect of the [database connection] is being configured.
1134 ** Subsequent arguments vary depending on the configuration verb.
1135 **
1136 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1137 ** the call is considered successful.
1138 */
1141 /*
1142 ** CAPI3REF: Memory Allocation Routines
1143 **
1144 ** An instance of this object defines the interface between SQLite
1145 ** and low-level memory allocation routines.
1146 **
1147 ** This object is used in only one place in the SQLite interface.
1148 ** A pointer to an instance of this object is the argument to
1149 ** [sqlite3_config()] when the configuration option is
1150 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1151 ** By creating an instance of this object
1152 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1153 ** during configuration, an application can specify an alternative
1154 ** memory allocation subsystem for SQLite to use for all of its
1155 ** dynamic memory needs.
1156 **
1157 ** Note that SQLite comes with several [built-in memory allocators]
1158 ** that are perfectly adequate for the overwhelming majority of applications
1159 ** and that this object is only useful to a tiny minority of applications
1160 ** with specialized memory allocation requirements. This object is
1161 ** also used during testing of SQLite in order to specify an alternative
1162 ** memory allocator that simulates memory out-of-memory conditions in
1163 ** order to verify that SQLite recovers gracefully from such
1164 ** conditions.
1165 **
1166 ** The xMalloc and xFree methods must work like the
1167 ** malloc() and free() functions from the standard C library.
1168 ** The xRealloc method must work like realloc() from the standard C library
1169 ** with the exception that if the second argument to xRealloc is zero,
1170 ** xRealloc must be a no-op - it must not perform any allocation or
1171 ** deallocation. ^SQLite guarantees that the second argument to
1172 ** xRealloc is always a value returned by a prior call to xRoundup.
1173 ** And so in cases where xRoundup always returns a positive number,
1174 ** xRealloc can perform exactly as the standard library realloc() and
1175 ** still be in compliance with this specification.
1176 **
1177 ** xSize should return the allocated size of a memory allocation
1178 ** previously obtained from xMalloc or xRealloc. The allocated size
1179 ** is always at least as big as the requested size but may be larger.
1180 **
1181 ** The xRoundup method returns what would be the allocated size of
1182 ** a memory allocation given a particular requested size. Most memory
1183 ** allocators round up memory allocations at least to the next multiple
1184 ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1185 ** Every memory allocation request coming in through [sqlite3_malloc()]
1186 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1187 ** that causes the corresponding memory allocation to fail.
1188 **
1189 ** The xInit method initializes the memory allocator. (For example,
1190 ** it might allocate any require mutexes or initialize internal data
1191 ** structures. The xShutdown method is invoked (indirectly) by
1192 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1193 ** by xInit. The pAppData pointer is used as the only parameter to
1194 ** xInit and xShutdown.
1195 **
1196 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1197 ** the xInit method, so the xInit method need not be threadsafe. The
1198 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1199 ** not need to be threadsafe either. For all other methods, SQLite
1200 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1201 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1202 ** it is by default) and so the methods are automatically serialized.
1203 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1204 ** methods must be threadsafe or else make their own arrangements for
1205 ** serialization.
1206 **
1207 ** SQLite will never invoke xInit() more than once without an intervening
1208 ** call to xShutdown().
1209 */
1220 };
1222 /*
1223 ** CAPI3REF: Configuration Options
1224 **
1225 ** These constants are the available integer configuration options that
1226 ** can be passed as the first argument to the [sqlite3_config()] interface.
1227 **
1228 ** New configuration options may be added in future releases of SQLite.
1229 ** Existing configuration options might be discontinued. Applications
1230 ** should check the return code from [sqlite3_config()] to make sure that
1231 ** the call worked. The [sqlite3_config()] interface will return a
1232 ** non-zero [error code] if a discontinued or unsupported configuration option
1233 ** is invoked.
1234 **
1235 ** <dl>
1236 ** <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1237 ** <dd>There are no arguments to this option. ^This option sets the
1238 ** [threading mode] to Single-thread. In other words, it disables
1239 ** all mutexing and puts SQLite into a mode where it can only be used
1240 ** by a single thread. ^If SQLite is compiled with
1241 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1242 ** it is not possible to change the [threading mode] from its default
1243 ** value of Single-thread and so [sqlite3_config()] will return
1244 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1245 ** configuration option.</dd>
1246 **
1247 ** <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1248 ** <dd>There are no arguments to this option. ^This option sets the
1249 ** [threading mode] to Multi-thread. In other words, it disables
1250 ** mutexing on [database connection] and [prepared statement] objects.
1251 ** The application is responsible for serializing access to
1252 ** [database connections] and [prepared statements]. But other mutexes
1253 ** are enabled so that SQLite will be safe to use in a multi-threaded
1254 ** environment as long as no two threads attempt to use the same
1255 ** [database connection] at the same time. ^If SQLite is compiled with
1256 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1257 ** it is not possible to set the Multi-thread [threading mode] and
1258 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1259 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1260 **
1261 ** <dt>SQLITE_CONFIG_SERIALIZED</dt>
1262 ** <dd>There are no arguments to this option. ^This option sets the
1263 ** [threading mode] to Serialized. In other words, this option enables
1264 ** all mutexes including the recursive
1265 ** mutexes on [database connection] and [prepared statement] objects.
1266 ** In this mode (which is the default when SQLite is compiled with
1267 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1268 ** to [database connections] and [prepared statements] so that the
1269 ** application is free to use the same [database connection] or the
1270 ** same [prepared statement] in different threads at the same time.
1271 ** ^If SQLite is compiled with
1272 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1273 ** it is not possible to set the Serialized [threading mode] and
1274 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1275 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1276 **
1277 ** <dt>SQLITE_CONFIG_MALLOC</dt>
1278 ** <dd> ^(This option takes a single argument which is a pointer to an
1279 ** instance of the [sqlite3_mem_methods] structure. The argument specifies
1280 ** alternative low-level memory allocation routines to be used in place of
1281 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1282 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1283 ** before the [sqlite3_config()] call returns.</dd>
1284 **
1285 ** <dt>SQLITE_CONFIG_GETMALLOC</dt>
1286 ** <dd> ^(This option takes a single argument which is a pointer to an
1287 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods]
1288 ** structure is filled with the currently defined memory allocation routines.)^
1289 ** This option can be used to overload the default memory allocation
1290 ** routines with a wrapper that simulations memory allocation failure or
1291 ** tracks memory usage, for example. </dd>
1292 **
1293 ** <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1294 ** <dd> ^This option takes single argument of type int, interpreted as a
1295 ** boolean, which enables or disables the collection of memory allocation
1296 ** statistics. ^(When memory allocation statistics are disabled, the
1297 ** following SQLite interfaces become non-operational:
1298 ** <ul>
1299 ** <li> [sqlite3_memory_used()]
1300 ** <li> [sqlite3_memory_highwater()]
1301 ** <li> [sqlite3_soft_heap_limit64()]
1302 ** <li> [sqlite3_status()]
1303 ** </ul>)^
1304 ** ^Memory allocation statistics are enabled by default unless SQLite is
1305 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1306 ** allocation statistics are disabled by default.
1307 ** </dd>
1308 **
1309 ** <dt>SQLITE_CONFIG_SCRATCH</dt>
1310 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1311 ** scratch memory. There are three arguments: A pointer an 8-byte
1312 ** aligned memory buffer from which the scratch allocations will be
1313 ** drawn, the size of each scratch allocation (sz),
1314 ** and the maximum number of scratch allocations (N). The sz
1315 ** argument must be a multiple of 16.
1316 ** The first argument must be a pointer to an 8-byte aligned buffer
1317 ** of at least sz*N bytes of memory.
1318 ** ^SQLite will use no more than two scratch buffers per thread. So
1319 ** N should be set to twice the expected maximum number of threads.
1320 ** ^SQLite will never require a scratch buffer that is more than 6
1321 ** times the database page size. ^If SQLite needs needs additional
1322 ** scratch memory beyond what is provided by this configuration option, then
1323 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
1324 **
1325 ** <dt>SQLITE_CONFIG_PAGECACHE</dt>
1326 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1327 ** the database page cache with the default page cache implemenation.
1328 ** This configuration should not be used if an application-define page
1329 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option.
1330 ** There are three arguments to this option: A pointer to 8-byte aligned
1331 ** memory, the size of each page buffer (sz), and the number of pages (N).
1332 ** The sz argument should be the size of the largest database page
1333 ** (a power of two between 512 and 32768) plus a little extra for each
1334 ** page header. ^The page header size is 20 to 40 bytes depending on
1335 ** the host architecture. ^It is harmless, apart from the wasted memory,
1336 ** to make sz a little too large. The first
1337 ** argument should point to an allocation of at least sz*N bytes of memory.
1338 ** ^SQLite will use the memory provided by the first argument to satisfy its
1339 ** memory needs for the first N pages that it adds to cache. ^If additional
1340 ** page cache memory is needed beyond what is provided by this option, then
1341 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
1342 ** The pointer in the first argument must
1343 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite
1344 ** will be undefined.</dd>
1345 **
1346 ** <dt>SQLITE_CONFIG_HEAP</dt>
1347 ** <dd> ^This option specifies a static memory buffer that SQLite will use
1348 ** for all of its dynamic memory allocation needs beyond those provided
1349 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
1350 ** There are three arguments: An 8-byte aligned pointer to the memory,
1351 ** the number of bytes in the memory buffer, and the minimum allocation size.
1352 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1353 ** to using its default memory allocator (the system malloc() implementation),
1354 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1355 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
1356 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
1357 ** allocator is engaged to handle all of SQLites memory allocation needs.
1358 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1359 ** boundary or subsequent behavior of SQLite will be undefined.
1360 ** The minimum allocation size is capped at 2^12. Reasonable values
1361 ** for the minimum allocation size are 2^5 through 2^8.</dd>
1362 **
1363 ** <dt>SQLITE_CONFIG_MUTEX</dt>
1364 ** <dd> ^(This option takes a single argument which is a pointer to an
1365 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies
1366 ** alternative low-level mutex routines to be used in place
1367 ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the
1368 ** content of the [sqlite3_mutex_methods] structure before the call to
1369 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1370 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1371 ** the entire mutexing subsystem is omitted from the build and hence calls to
1372 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1373 ** return [SQLITE_ERROR].</dd>
1374 **
1375 ** <dt>SQLITE_CONFIG_GETMUTEX</dt>
1376 ** <dd> ^(This option takes a single argument which is a pointer to an
1377 ** instance of the [sqlite3_mutex_methods] structure. The
1378 ** [sqlite3_mutex_methods]
1379 ** structure is filled with the currently defined mutex routines.)^
1380 ** This option can be used to overload the default mutex allocation
1381 ** routines with a wrapper used to track mutex usage for performance
1382 ** profiling or testing, for example. ^If SQLite is compiled with
1383 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1384 ** the entire mutexing subsystem is omitted from the build and hence calls to
1385 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1386 ** return [SQLITE_ERROR].</dd>
1387 **
1388 ** <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1389 ** <dd> ^(This option takes two arguments that determine the default
1390 ** memory allocation for the lookaside memory allocator on each
1391 ** [database connection]. The first argument is the
1392 ** size of each lookaside buffer slot and the second is the number of
1393 ** slots allocated to each database connection.)^ ^(This option sets the
1394 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1395 ** verb to [sqlite3_db_config()] can be used to change the lookaside
1396 ** configuration on individual connections.)^ </dd>
1397 **
1398 ** <dt>SQLITE_CONFIG_PCACHE</dt>
1399 ** <dd> ^(This option takes a single argument which is a pointer to
1400 ** an [sqlite3_pcache_methods] object. This object specifies the interface
1401 ** to a custom page cache implementation.)^ ^SQLite makes a copy of the
1402 ** object and uses it for page cache memory allocations.</dd>
1403 **
1404 ** <dt>SQLITE_CONFIG_GETPCACHE</dt>
1405 ** <dd> ^(This option takes a single argument which is a pointer to an
1406 ** [sqlite3_pcache_methods] object. SQLite copies of the current
1407 ** page cache implementation into that object.)^ </dd>
1408 **
1409 ** <dt>SQLITE_CONFIG_LOG</dt>
1410 ** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1411 ** function with a call signature of void(*)(void*,int,const char*),
1412 ** and a pointer to void. ^If the function pointer is not NULL, it is
1413 ** invoked by [sqlite3_log()] to process each logging event. ^If the
1414 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1415 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1416 ** passed through as the first parameter to the application-defined logger
1417 ** function whenever that function is invoked. ^The second parameter to
1418 ** the logger function is a copy of the first parameter to the corresponding
1419 ** [sqlite3_log()] call and is intended to be a [result code] or an
1420 ** [extended result code]. ^The third parameter passed to the logger is
1421 ** log message after formatting via [sqlite3_snprintf()].
1422 ** The SQLite logging interface is not reentrant; the logger function
1423 ** supplied by the application must not invoke any SQLite interface.
1424 ** In a multi-threaded application, the application-defined logger
1425 ** function must be threadsafe. </dd>
1426 **
1427 ** </dl>
1428 */
1440 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1446 /*
1447 ** CAPI3REF: Database Connection Configuration Options
1448 **
1449 ** These constants are the available integer configuration options that
1450 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1451 **
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_db_config()] to make sure that
1455 ** the call worked. ^The [sqlite3_db_config()] interface will return a
1456 ** non-zero [error code] if a discontinued or unsupported configuration option
1457 ** is invoked.
1458 **
1459 ** <dl>
1460 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1461 ** <dd> ^This option takes three additional arguments that determine the
1462 ** [lookaside memory allocator] configuration for the [database connection].
1463 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1464 ** pointer to a memory buffer to use for lookaside memory.
1465 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1466 ** may be NULL in which case SQLite will allocate the
1467 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1468 ** size of each lookaside buffer slot. ^The third argument is the number of
1469 ** slots. The size of the buffer in the first argument must be greater than
1470 ** or equal to the product of the second and third arguments. The buffer
1471 ** must be aligned to an 8-byte boundary. ^If the second argument to
1472 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1473 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
1474 ** configuration for a database connection can only be changed when that
1475 ** connection is not currently using lookaside memory, or in other words
1476 ** when the "current value" returned by
1477 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1478 ** Any attempt to change the lookaside memory configuration when lookaside
1479 ** memory is in use leaves the configuration unchanged and returns
1480 ** [SQLITE_BUSY].)^</dd>
1481 **
1482 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1483 ** <dd> ^This option is used to enable or disable the enforcement of
1484 ** [foreign key constraints]. There should be two additional arguments.
1485 ** The first argument is an integer which is 0 to disable FK enforcement,
1486 ** positive to enable FK enforcement or negative to leave FK enforcement
1487 ** unchanged. The second parameter is a pointer to an integer into which
1488 ** is written 0 or 1 to indicate whether FK enforcement is off or on
1489 ** following this call. The second parameter may be a NULL pointer, in
1490 ** which case the FK enforcement setting is not reported back. </dd>
1491 **
1492 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1493 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1494 ** There should be two additional arguments.
1495 ** The first argument is an integer which is 0 to disable triggers,
1496 ** positive to enable triggers or negative to leave the setting unchanged.
1497 ** The second parameter is a pointer to an integer into which
1498 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
1499 ** following this call. The second parameter may be a NULL pointer, in
1500 ** which case the trigger setting is not reported back. </dd>
1501 **
1502 ** </dl>
1503 */
1509 /*
1510 ** CAPI3REF: Enable Or Disable Extended Result Codes
1511 **
1512 ** ^The sqlite3_extended_result_codes() routine enables or disables the
1513 ** [extended result codes] feature of SQLite. ^The extended result
1514 ** codes are disabled by default for historical compatibility.
1515 */
1518 /*
1519 ** CAPI3REF: Last Insert Rowid
1520 **
1521 ** ^Each entry in an SQLite table has a unique 64-bit signed
1522 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1523 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1524 ** names are not also used by explicitly declared columns. ^If
1525 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
1526 ** is another alias for the rowid.
1527 **
1528 ** ^This routine returns the [rowid] of the most recent
1529 ** successful [INSERT] into the database from the [database connection]
1530 ** in the first argument. ^If no successful [INSERT]s
1531 ** have ever occurred on that database connection, zero is returned.
1532 **
1533 ** ^(If an [INSERT] occurs within a trigger, then the [rowid] of the inserted
1534 ** row is returned by this routine as long as the trigger is running.
1535 ** But once the trigger terminates, the value returned by this routine
1536 ** reverts to the last value inserted before the trigger fired.)^
1537 **
1538 ** ^An [INSERT] that fails due to a constraint violation is not a
1539 ** successful [INSERT] and does not change the value returned by this
1540 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1541 ** and INSERT OR ABORT make no changes to the return value of this
1542 ** routine when their insertion fails. ^(When INSERT OR REPLACE
1543 ** encounters a constraint violation, it does not fail. The
1544 ** INSERT continues to completion after deleting rows that caused
1545 ** the constraint problem so INSERT OR REPLACE will always change
1546 ** the return value of this interface.)^
1547 **
1548 ** ^For the purposes of this routine, an [INSERT] is considered to
1549 ** be successful even if it is subsequently rolled back.
1550 **
1551 ** This function is accessible to SQL statements via the
1552 ** [last_insert_rowid() SQL function].
1553 **
1554 ** If a separate thread performs a new [INSERT] on the same
1555 ** database connection while the [sqlite3_last_insert_rowid()]
1556 ** function is running and thus changes the last insert [rowid],
1557 ** then the value returned by [sqlite3_last_insert_rowid()] is
1558 ** unpredictable and might not equal either the old or the new
1559 ** last insert [rowid].
1560 */
1563 /*
1564 ** CAPI3REF: Count The Number Of Rows Modified
1565 **
1566 ** ^This function returns the number of database rows that were changed
1567 ** or inserted or deleted by the most recently completed SQL statement
1568 ** on the [database connection] specified by the first parameter.
1569 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
1570 ** or [DELETE] statement are counted. Auxiliary changes caused by
1571 ** triggers or [foreign key actions] are not counted.)^ Use the
1572 ** [sqlite3_total_changes()] function to find the total number of changes
1573 ** including changes caused by triggers and foreign key actions.
1574 **
1575 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
1576 ** are not counted. Only real table changes are counted.
1577 **
1578 ** ^(A "row change" is a change to a single row of a single table
1579 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that
1580 ** are changed as side effects of [REPLACE] constraint resolution,
1581 ** rollback, ABORT processing, [DROP TABLE], or by any other
1582 ** mechanisms do not count as direct row changes.)^
1583 **
1584 ** A "trigger context" is a scope of execution that begins and
1585 ** ends with the script of a [CREATE TRIGGER | trigger].
1586 ** Most SQL statements are
1587 ** evaluated outside of any trigger. This is the "top level"
1588 ** trigger context. If a trigger fires from the top level, a
1589 ** new trigger context is entered for the duration of that one
1590 ** trigger. Subtriggers create subcontexts for their duration.
1591 **
1592 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
1593 ** not create a new trigger context.
1594 **
1595 ** ^This function returns the number of direct row changes in the
1596 ** most recent INSERT, UPDATE, or DELETE statement within the same
1597 ** trigger context.
1598 **
1599 ** ^Thus, when called from the top level, this function returns the
1600 ** number of changes in the most recent INSERT, UPDATE, or DELETE
1601 ** that also occurred at the top level. ^(Within the body of a trigger,
1602 ** the sqlite3_changes() interface can be called to find the number of
1603 ** changes in the most recently completed INSERT, UPDATE, or DELETE
1604 ** statement within the body of the same trigger.
1605 ** However, the number returned does not include changes
1606 ** caused by subtriggers since those have their own context.)^
1607 **
1608 ** See also the [sqlite3_total_changes()] interface, the
1609 ** [count_changes pragma], and the [changes() SQL function].
1610 **
1611 ** If a separate thread makes changes on the same database connection
1612 ** while [sqlite3_changes()] is running then the value returned
1613 ** is unpredictable and not meaningful.
1614 */
1617 /*
1618 ** CAPI3REF: Total Number Of Rows Modified
1619 **
1620 ** ^This function returns the number of row changes caused by [INSERT],
1621 ** [UPDATE] or [DELETE] statements since the [database connection] was opened.
1622 ** ^(The count returned by sqlite3_total_changes() includes all changes
1623 ** from all [CREATE TRIGGER | trigger] contexts and changes made by
1624 ** [foreign key actions]. However,
1625 ** the count does not include changes used to implement [REPLACE] constraints,
1626 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The
1627 ** count does not include rows of views that fire an [INSTEAD OF trigger],
1628 ** though if the INSTEAD OF trigger makes changes of its own, those changes
1629 ** are counted.)^
1630 ** ^The sqlite3_total_changes() function counts the changes as soon as
1631 ** the statement that makes them is completed (when the statement handle
1632 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
1633 **
1634 ** See also the [sqlite3_changes()] interface, the
1635 ** [count_changes pragma], and the [total_changes() SQL function].
1636 **
1637 ** If a separate thread makes changes on the same database connection
1638 ** while [sqlite3_total_changes()] is running then the value
1639 ** returned is unpredictable and not meaningful.
1640 */
1643 /*
1644 ** CAPI3REF: Interrupt A Long-Running Query
1645 **
1646 ** ^This function causes any pending database operation to abort and
1647 ** return at its earliest opportunity. This routine is typically
1648 ** called in response to a user action such as pressing "Cancel"
1649 ** or Ctrl-C where the user wants a long query operation to halt
1650 ** immediately.
1651 **
1652 ** ^It is safe to call this routine from a thread different from the
1653 ** thread that is currently running the database operation. But it
1654 ** is not safe to call this routine with a [database connection] that
1655 ** is closed or might close before sqlite3_interrupt() returns.
1656 **
1657 ** ^If an SQL operation is very nearly finished at the time when
1658 ** sqlite3_interrupt() is called, then it might not have an opportunity
1659 ** to be interrupted and might continue to completion.
1660 **
1661 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
1662 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
1663 ** that is inside an explicit transaction, then the entire transaction
1664 ** will be rolled back automatically.
1665 **
1666 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
1667 ** SQL statements on [database connection] D complete. ^Any new SQL statements
1668 ** that are started after the sqlite3_interrupt() call and before the
1669 ** running statements reaches zero are interrupted as if they had been
1670 ** running prior to the sqlite3_interrupt() call. ^New SQL statements
1671 ** that are started after the running statement count reaches zero are
1672 ** not effected by the sqlite3_interrupt().
1673 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
1674 ** SQL statements is a no-op and has no effect on SQL statements
1675 ** that are started after the sqlite3_interrupt() call returns.
1676 **
1677 ** If the database connection closes while [sqlite3_interrupt()]
1678 ** is running then bad things will likely happen.
1679 */
1682 /*
1683 ** CAPI3REF: Determine If An SQL Statement Is Complete
1684 **
1685 ** These routines are useful during command-line input to determine if the
1686 ** currently entered text seems to form a complete SQL statement or
1687 ** if additional input is needed before sending the text into
1688 ** SQLite for parsing. ^These routines return 1 if the input string
1689 ** appears to be a complete SQL statement. ^A statement is judged to be
1690 ** complete if it ends with a semicolon token and is not a prefix of a
1691 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
1692 ** string literals or quoted identifier names or comments are not
1693 ** independent tokens (they are part of the token in which they are
1694 ** embedded) and thus do not count as a statement terminator. ^Whitespace
1695 ** and comments that follow the final semicolon are ignored.
1696 **
1697 ** ^These routines return 0 if the statement is incomplete. ^If a
1698 ** memory allocation fails, then SQLITE_NOMEM is returned.
1699 **
1700 ** ^These routines do not parse the SQL statements thus
1701 ** will not detect syntactically incorrect SQL.
1702 **
1703 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
1704 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
1705 ** automatically by sqlite3_complete16(). If that initialization fails,
1706 ** then the return value from sqlite3_complete16() will be non-zero
1707 ** regardless of whether or not the input SQL is complete.)^
1708 **
1709 ** The input to [sqlite3_complete()] must be a zero-terminated
1710 ** UTF-8 string.
1711 **
1712 ** The input to [sqlite3_complete16()] must be a zero-terminated
1713 ** UTF-16 string in native byte order.
1714 */
1718 /*
1719 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
1720 **
1721 ** ^This routine sets a callback function that might be invoked whenever
1722 ** an attempt is made to open a database table that another thread
1723 ** or process has locked.
1724 **
1725 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
1726 ** is returned immediately upon encountering the lock. ^If the busy callback
1727 ** is not NULL, then the callback might be invoked with two arguments.
1728 **
1729 ** ^The first argument to the busy handler is a copy of the void* pointer which
1730 ** is the third argument to sqlite3_busy_handler(). ^The second argument to
1731 ** the busy handler callback is the number of times that the busy handler has
1732 ** been invoked for this locking event. ^If the
1733 ** busy callback returns 0, then no additional attempts are made to
1734 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
1735 ** ^If the callback returns non-zero, then another attempt
1736 ** is made to open the database for reading and the cycle repeats.
1737 **
1738 ** The presence of a busy handler does not guarantee that it will be invoked
1739 ** when there is lock contention. ^If SQLite determines that invoking the busy
1740 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
1741 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
1742 ** Consider a scenario where one process is holding a read lock that
1743 ** it is trying to promote to a reserved lock and
1744 ** a second process is holding a reserved lock that it is trying
1745 ** to promote to an exclusive lock. The first process cannot proceed
1746 ** because it is blocked by the second and the second process cannot
1747 ** proceed because it is blocked by the first. If both processes
1748 ** invoke the busy handlers, neither will make any progress. Therefore,
1749 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
1750 ** will induce the first process to release its read lock and allow
1751 ** the second process to proceed.
1752 **
1753 ** ^The default busy callback is NULL.
1754 **
1755 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
1756 ** when SQLite is in the middle of a large transaction where all the
1757 ** changes will not fit into the in-memory cache. SQLite will
1758 ** already hold a RESERVED lock on the database file, but it needs
1759 ** to promote this lock to EXCLUSIVE so that it can spill cache
1760 ** pages into the database file without harm to concurrent
1761 ** readers. ^If it is unable to promote the lock, then the in-memory
1762 ** cache will be left in an inconsistent state and so the error
1763 ** code is promoted from the relatively benign [SQLITE_BUSY] to
1764 ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion
1765 ** forces an automatic rollback of the changes. See the
1766 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
1767 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
1768 ** this is important.
1769 **
1770 ** ^(There can only be a single busy handler defined for each
1771 ** [database connection]. Setting a new busy handler clears any
1772 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
1773 ** will also set or clear the busy handler.
1774 **
1775 ** The busy callback should not take any actions which modify the
1776 ** database connection that invoked the busy handler. Any such actions
1777 ** result in undefined behavior.
1778 **
1779 ** A busy handler must not close the database connection
1780 ** or [prepared statement] that invoked the busy handler.
1781 */
1784 /*
1785 ** CAPI3REF: Set A Busy Timeout
1786 **
1787 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
1788 ** for a specified amount of time when a table is locked. ^The handler
1789 ** will sleep multiple times until at least "ms" milliseconds of sleeping
1790 ** have accumulated. ^After at least "ms" milliseconds of sleeping,
1791 ** the handler returns 0 which causes [sqlite3_step()] to return
1792 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
1793 **
1794 ** ^Calling this routine with an argument less than or equal to zero
1795 ** turns off all busy handlers.
1796 **
1797 ** ^(There can only be a single busy handler for a particular
1798 ** [database connection] any any given moment. If another busy handler
1799 ** was defined (using [sqlite3_busy_handler()]) prior to calling
1800 ** this routine, that other busy handler is cleared.)^
1801 */
1804 /*
1805 ** CAPI3REF: Convenience Routines For Running Queries
1806 **
1807 ** This is a legacy interface that is preserved for backwards compatibility.
1808 ** Use of this interface is not recommended.
1809 **
1810 ** Definition: A <b>result table</b> is memory data structure created by the
1811 ** [sqlite3_get_table()] interface. A result table records the
1812 ** complete query results from one or more queries.
1813 **
1814 ** The table conceptually has a number of rows and columns. But
1815 ** these numbers are not part of the result table itself. These
1816 ** numbers are obtained separately. Let N be the number of rows
1817 ** and M be the number of columns.
1818 **
1819 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
1820 ** There are (N+1)*M elements in the array. The first M pointers point
1821 ** to zero-terminated strings that contain the names of the columns.
1822 ** The remaining entries all point to query results. NULL values result
1823 ** in NULL pointers. All other values are in their UTF-8 zero-terminated
1824 ** string representation as returned by [sqlite3_column_text()].
1825 **
1826 ** A result table might consist of one or more memory allocations.
1827 ** It is not safe to pass a result table directly to [sqlite3_free()].
1828 ** A result table should be deallocated using [sqlite3_free_table()].
1829 **
1830 ** ^(As an example of the result table format, suppose a query result
1831 ** is as follows:
1832 **
1833 ** <blockquote><pre>
1834 ** Name | Age
1835 ** -----------------------
1836 ** Alice | 43
1837 ** Bob | 28
1838 ** Cindy | 21
1839 ** </pre></blockquote>
1840 **
1841 ** There are two column (M==2) and three rows (N==3). Thus the
1842 ** result table has 8 entries. Suppose the result table is stored
1843 ** in an array names azResult. Then azResult holds this content:
1844 **
1845 ** <blockquote><pre>
1846 ** azResult[0] = "Name";
1847 ** azResult[1] = "Age";
1848 ** azResult[2] = "Alice";
1849 ** azResult[3] = "43";
1850 ** azResult[4] = "Bob";
1851 ** azResult[5] = "28";
1852 ** azResult[6] = "Cindy";
1853 ** azResult[7] = "21";
1854 ** </pre></blockquote>)^
1855 **
1856 ** ^The sqlite3_get_table() function evaluates one or more
1857 ** semicolon-separated SQL statements in the zero-terminated UTF-8
1858 ** string of its 2nd parameter and returns a result table to the
1859 ** pointer given in its 3rd parameter.
1860 **
1861 ** After the application has finished with the result from sqlite3_get_table(),
1862 ** it must pass the result table pointer to sqlite3_free_table() in order to
1863 ** release the memory that was malloced. Because of the way the
1864 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
1865 ** function must not try to call [sqlite3_free()] directly. Only
1866 ** [sqlite3_free_table()] is able to release the memory properly and safely.
1867 **
1868 ** The sqlite3_get_table() interface is implemented as a wrapper around
1869 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
1870 ** to any internal data structures of SQLite. It uses only the public
1871 ** interface defined here. As a consequence, errors that occur in the
1872 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
1873 ** reflected in subsequent calls to [sqlite3_errcode()] or
1874 ** [sqlite3_errmsg()].
1875 */
1883 );
1886 /*
1887 ** CAPI3REF: Formatted String Printing Functions
1888 **
1889 ** These routines are work-alikes of the "printf()" family of functions
1890 ** from the standard C library.
1891 **
1892 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
1893 ** results into memory obtained from [sqlite3_malloc()].
1894 ** The strings returned by these two routines should be
1895 ** released by [sqlite3_free()]. ^Both routines return a
1896 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
1897 ** memory to hold the resulting string.
1898 **
1899 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
1900 ** the standard C library. The result is written into the
1901 ** buffer supplied as the second parameter whose size is given by
1902 ** the first parameter. Note that the order of the
1903 ** first two parameters is reversed from snprintf().)^ This is an
1904 ** historical accident that cannot be fixed without breaking
1905 ** backwards compatibility. ^(Note also that sqlite3_snprintf()
1906 ** returns a pointer to its buffer instead of the number of
1907 ** characters actually written into the buffer.)^ We admit that
1908 ** the number of characters written would be a more useful return
1909 ** value but we cannot change the implementation of sqlite3_snprintf()
1910 ** now without breaking compatibility.
1911 **
1912 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
1913 ** guarantees that the buffer is always zero-terminated. ^The first
1914 ** parameter "n" is the total size of the buffer, including space for
1915 ** the zero terminator. So the longest string that can be completely
1916 ** written will be n-1 characters.
1917 **
1918 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
1919 **
1920 ** These routines all implement some additional formatting
1921 ** options that are useful for constructing SQL statements.
1922 ** All of the usual printf() formatting options apply. In addition, there
1923 ** is are "%q", "%Q", and "%z" options.
1924 **
1925 ** ^(The %q option works like %s in that it substitutes a null-terminated
1926 ** string from the argument list. But %q also doubles every '\'' character.
1927 ** %q is designed for use inside a string literal.)^ By doubling each '\''
1928 ** character it escapes that character and allows it to be inserted into
1929 ** the string.
1930 **
1931 ** For example, assume the string variable zText contains text as follows:
1932 **
1933 ** <blockquote><pre>
1934 ** char *zText = "It's a happy day!";
1935 ** </pre></blockquote>
1936 **
1937 ** One can use this text in an SQL statement as follows:
1938 **
1939 ** <blockquote><pre>
1940 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
1941 ** sqlite3_exec(db, zSQL, 0, 0, 0);
1942 ** sqlite3_free(zSQL);
1943 ** </pre></blockquote>
1944 **
1945 ** Because the %q format string is used, the '\'' character in zText
1946 ** is escaped and the SQL generated is as follows:
1947 **
1948 ** <blockquote><pre>
1949 ** INSERT INTO table1 VALUES('It''s a happy day!')
1950 ** </pre></blockquote>
1951 **
1952 ** This is correct. Had we used %s instead of %q, the generated SQL
1953 ** would have looked like this:
1954 **
1955 ** <blockquote><pre>
1956 ** INSERT INTO table1 VALUES('It's a happy day!');
1957 ** </pre></blockquote>
1958 **
1959 ** This second example is an SQL syntax error. As a general rule you should
1960 ** always use %q instead of %s when inserting text into a string literal.
1961 **
1962 ** ^(The %Q option works like %q except it also adds single quotes around
1963 ** the outside of the total string. Additionally, if the parameter in the
1964 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
1965 ** single quotes).)^ So, for example, one could say:
1966 **
1967 ** <blockquote><pre>
1968 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
1969 ** sqlite3_exec(db, zSQL, 0, 0, 0);
1970 ** sqlite3_free(zSQL);
1971 ** </pre></blockquote>
1972 **
1973 ** The code above will render a correct SQL statement in the zSQL
1974 ** variable even if the zText variable is a NULL pointer.
1975 **
1976 ** ^(The "%z" formatting option works like "%s" but with the
1977 ** addition that after the string has been read and copied into
1978 ** the result, [sqlite3_free()] is called on the input string.)^
1979 */
1985 /*
1986 ** CAPI3REF: Memory Allocation Subsystem
1987 **
1988 ** The SQLite core uses these three routines for all of its own
1989 ** internal memory allocation needs. "Core" in the previous sentence
1990 ** does not include operating-system specific VFS implementation. The
1991 ** Windows VFS uses native malloc() and free() for some operations.
1992 **
1993 ** ^The sqlite3_malloc() routine returns a pointer to a block
1994 ** of memory at least N bytes in length, where N is the parameter.
1995 ** ^If sqlite3_malloc() is unable to obtain sufficient free
1996 ** memory, it returns a NULL pointer. ^If the parameter N to
1997 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
1998 ** a NULL pointer.
1999 **
2000 ** ^Calling sqlite3_free() with a pointer previously returned
2001 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2002 ** that it might be reused. ^The sqlite3_free() routine is
2003 ** a no-op if is called with a NULL pointer. Passing a NULL pointer
2004 ** to sqlite3_free() is harmless. After being freed, memory
2005 ** should neither be read nor written. Even reading previously freed
2006 ** memory might result in a segmentation fault or other severe error.
2007 ** Memory corruption, a segmentation fault, or other severe error
2008 ** might result if sqlite3_free() is called with a non-NULL pointer that
2009 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2010 **
2011 ** ^(The sqlite3_realloc() interface attempts to resize a
2012 ** prior memory allocation to be at least N bytes, where N is the
2013 ** second parameter. The memory allocation to be resized is the first
2014 ** parameter.)^ ^ If the first parameter to sqlite3_realloc()
2015 ** is a NULL pointer then its behavior is identical to calling
2016 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
2017 ** ^If the second parameter to sqlite3_realloc() is zero or
2018 ** negative then the behavior is exactly the same as calling
2019 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
2020 ** ^sqlite3_realloc() returns a pointer to a memory allocation
2021 ** of at least N bytes in size or NULL if sufficient memory is unavailable.
2022 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2023 ** of the prior allocation are copied into the beginning of buffer returned
2024 ** by sqlite3_realloc() and the prior allocation is freed.
2025 ** ^If sqlite3_realloc() returns NULL, then the prior allocation
2026 ** is not freed.
2027 **
2028 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
2029 ** is always aligned to at least an 8 byte boundary, or to a
2030 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2031 ** option is used.
2032 **
2033 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2034 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2035 ** implementation of these routines to be omitted. That capability
2036 ** is no longer provided. Only built-in memory allocators can be used.
2037 **
2038 ** The Windows OS interface layer calls
2039 ** the system malloc() and free() directly when converting
2040 ** filenames between the UTF-8 encoding used by SQLite
2041 ** and whatever filename encoding is used by the particular Windows
2042 ** installation. Memory allocation errors are detected, but
2043 ** they are reported back as [SQLITE_CANTOPEN] or
2044 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2045 **
2046 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2047 ** must be either NULL or else pointers obtained from a prior
2048 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2049 ** not yet been released.
2050 **
2051 ** The application must not read or write any part of
2052 ** a block of memory after it has been released using
2053 ** [sqlite3_free()] or [sqlite3_realloc()].
2054 */
2059 /*
2060 ** CAPI3REF: Memory Allocator Statistics
2061 **
2062 ** SQLite provides these two interfaces for reporting on the status
2063 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2064 ** routines, which form the built-in memory allocation subsystem.
2065 **
2066 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2067 ** of memory currently outstanding (malloced but not freed).
2068 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2069 ** value of [sqlite3_memory_used()] since the high-water mark
2070 ** was last reset. ^The values returned by [sqlite3_memory_used()] and
2071 ** [sqlite3_memory_highwater()] include any overhead
2072 ** added by SQLite in its implementation of [sqlite3_malloc()],
2073 ** but not overhead added by the any underlying system library
2074 ** routines that [sqlite3_malloc()] may call.
2075 **
2076 ** ^The memory high-water mark is reset to the current value of
2077 ** [sqlite3_memory_used()] if and only if the parameter to
2078 ** [sqlite3_memory_highwater()] is true. ^The value returned
2079 ** by [sqlite3_memory_highwater(1)] is the high-water mark
2080 ** prior to the reset.
2081 */
2085 /*
2086 ** CAPI3REF: Pseudo-Random Number Generator
2087 **
2088 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2089 ** select random [ROWID | ROWIDs] when inserting new records into a table that
2090 ** already uses the largest possible [ROWID]. The PRNG is also used for
2091 ** the build-in random() and randomblob() SQL functions. This interface allows
2092 ** applications to access the same PRNG for other purposes.
2093 **
2094 ** ^A call to this routine stores N bytes of randomness into buffer P.
2095 **
2096 ** ^The first time this routine is invoked (either internally or by
2097 ** the application) the PRNG is seeded using randomness obtained
2098 ** from the xRandomness method of the default [sqlite3_vfs] object.
2099 ** ^On all subsequent invocations, the pseudo-randomness is generated
2100 ** internally and without recourse to the [sqlite3_vfs] xRandomness
2101 ** method.
2102 */
2105 /*
2106 ** CAPI3REF: Compile-Time Authorization Callbacks
2107 **
2108 ** ^This routine registers an authorizer callback with a particular
2109 ** [database connection], supplied in the first argument.
2110 ** ^The authorizer callback is invoked as SQL statements are being compiled
2111 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2112 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various
2113 ** points during the compilation process, as logic is being created
2114 ** to perform various actions, the authorizer callback is invoked to
2115 ** see if those actions are allowed. ^The authorizer callback should
2116 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2117 ** specific action but allow the SQL statement to continue to be
2118 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2119 ** rejected with an error. ^If the authorizer callback returns
2120 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2121 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2122 ** the authorizer will fail with an error message.
2123 **
2124 ** When the callback returns [SQLITE_OK], that means the operation
2125 ** requested is ok. ^When the callback returns [SQLITE_DENY], the
2126 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2127 ** authorizer will fail with an error message explaining that
2128 ** access is denied.
2129 **
2130 ** ^The first parameter to the authorizer callback is a copy of the third
2131 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2132 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2133 ** the particular action to be authorized. ^The third through sixth parameters
2134 ** to the callback are zero-terminated strings that contain additional
2135 ** details about the action to be authorized.
2136 **
2137 ** ^If the action code is [SQLITE_READ]
2138 ** and the callback returns [SQLITE_IGNORE] then the
2139 ** [prepared statement] statement is constructed to substitute
2140 ** a NULL value in place of the table column that would have
2141 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2142 ** return can be used to deny an untrusted user access to individual
2143 ** columns of a table.
2144 ** ^If the action code is [SQLITE_DELETE] and the callback returns
2145 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2146 ** [truncate optimization] is disabled and all rows are deleted individually.
2147 **
2148 ** An authorizer is used when [sqlite3_prepare | preparing]
2149 ** SQL statements from an untrusted source, to ensure that the SQL statements
2150 ** do not try to access data they are not allowed to see, or that they do not
2151 ** try to execute malicious statements that damage the database. For
2152 ** example, an application may allow a user to enter arbitrary
2153 ** SQL queries for evaluation by a database. But the application does
2154 ** not want the user to be able to make arbitrary changes to the
2155 ** database. An authorizer could then be put in place while the
2156 ** user-entered SQL is being [sqlite3_prepare | prepared] that
2157 ** disallows everything except [SELECT] statements.
2158 **
2159 ** Applications that need to process SQL from untrusted sources
2160 ** might also consider lowering resource limits using [sqlite3_limit()]
2161 ** and limiting database size using the [max_page_count] [PRAGMA]
2162 ** in addition to using an authorizer.
2163 **
2164 ** ^(Only a single authorizer can be in place on a database connection
2165 ** at a time. Each call to sqlite3_set_authorizer overrides the
2166 ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2167 ** The authorizer is disabled by default.
2168 **
2169 ** The authorizer callback must not do anything that will modify
2170 ** the database connection that invoked the authorizer callback.
2171 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2172 ** database connections for the meaning of "modify" in this paragraph.
2173 **
2174 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2175 ** statement might be re-prepared during [sqlite3_step()] due to a
2176 ** schema change. Hence, the application should ensure that the
2177 ** correct authorizer callback remains in place during the [sqlite3_step()].
2178 **
2179 ** ^Note that the authorizer callback is invoked only during
2180 ** [sqlite3_prepare()] or its variants. Authorization is not
2181 ** performed during statement evaluation in [sqlite3_step()], unless
2182 ** as stated in the previous paragraph, sqlite3_step() invokes
2183 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2184 */
2186 sqlite3*,
2189 );
2191 /*
2192 ** CAPI3REF: Authorizer Return Codes
2193 **
2194 ** The [sqlite3_set_authorizer | authorizer callback function] must
2195 ** return either [SQLITE_OK] or one of these two constants in order
2196 ** to signal SQLite whether or not the action is permitted. See the
2197 ** [sqlite3_set_authorizer | authorizer documentation] for additional
2198 ** information.
2199 */
2203 /*
2204 ** CAPI3REF: Authorizer Action Codes
2205 **
2206 ** The [sqlite3_set_authorizer()] interface registers a callback function
2207 ** that is invoked to authorize certain SQL statement actions. The
2208 ** second parameter to the callback is an integer code that specifies
2209 ** what action is being authorized. These are the integer action codes that
2210 ** the authorizer callback may be passed.
2211 **
2212 ** These action code values signify what kind of operation is to be
2213 ** authorized. The 3rd and 4th parameters to the authorization
2214 ** callback function will be parameters or NULL depending on which of these
2215 ** codes is used as the second parameter. ^(The 5th parameter to the
2216 ** authorizer callback is the name of the database ("main", "temp",
2217 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2218 ** is the name of the inner-most trigger or view that is responsible for
2219 ** the access attempt or NULL if this access attempt is directly from
2220 ** top-level SQL code.
2221 */
2222 /******************************************* 3rd ************ 4th ***********/
2257 /*
2258 ** CAPI3REF: Tracing And Profiling Functions
2259 **
2260 ** These routines register callback functions that can be used for
2261 ** tracing and profiling the execution of SQL statements.
2262 **
2263 ** ^The callback function registered by sqlite3_trace() is invoked at
2264 ** various times when an SQL statement is being run by [sqlite3_step()].
2265 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2266 ** SQL statement text as the statement first begins executing.
2267 ** ^(Additional sqlite3_trace() callbacks might occur
2268 ** as each triggered subprogram is entered. The callbacks for triggers
2269 ** contain a UTF-8 SQL comment that identifies the trigger.)^
2270 **
2271 ** ^The callback function registered by sqlite3_profile() is invoked
2272 ** as each SQL statement finishes. ^The profile callback contains
2273 ** the original statement text and an estimate of wall-clock time
2274 ** of how long that statement took to run. ^The profile callback
2275 ** time is in units of nanoseconds, however the current implementation
2276 ** is only capable of millisecond resolution so the six least significant
2277 ** digits in the time are meaningless. Future versions of SQLite
2278 ** might provide greater resolution on the profiler callback. The
2279 ** sqlite3_profile() function is considered experimental and is
2280 ** subject to change in future versions of SQLite.
2281 */
2286 /*
2287 ** CAPI3REF: Query Progress Callbacks
2288 **
2289 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2290 ** function X to be invoked periodically during long running calls to
2291 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2292 ** database connection D. An example use for this
2293 ** interface is to keep a GUI updated during a large query.
2294 **
2295 ** ^The parameter P is passed through as the only parameter to the
2296 ** callback function X. ^The parameter N is the number of
2297 ** [virtual machine instructions] that are evaluated between successive
2298 ** invocations of the callback X.
2299 **
2300 ** ^Only a single progress handler may be defined at one time per
2301 ** [database connection]; setting a new progress handler cancels the
2302 ** old one. ^Setting parameter X to NULL disables the progress handler.
2303 ** ^The progress handler is also disabled by setting N to a value less
2304 ** than 1.
2305 **
2306 ** ^If the progress callback returns non-zero, the operation is
2307 ** interrupted. This feature can be used to implement a
2308 ** "Cancel" button on a GUI progress dialog box.
2309 **
2310 ** The progress handler callback must not do anything that will modify
2311 ** the database connection that invoked the progress handler.
2312 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2313 ** database connections for the meaning of "modify" in this paragraph.
2314 **
2315 */
2318 /*
2319 ** CAPI3REF: Opening A New Database Connection
2320 **
2321 ** ^These routines open an SQLite database file whose name is given by the
2322 ** filename argument. ^The filename argument is interpreted as UTF-8 for
2323 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2324 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
2325 ** returned in *ppDb, even if an error occurs. The only exception is that
2326 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2327 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2328 ** object.)^ ^(If the database is opened (and/or created) successfully, then
2329 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
2330 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2331 ** an English language description of the error following a failure of any
2332 ** of the sqlite3_open() routines.
2333 **
2334 ** ^The default encoding for the database will be UTF-8 if
2335 ** sqlite3_open() or sqlite3_open_v2() is called and
2336 ** UTF-16 in the native byte order if sqlite3_open16() is used.
2337 **
2338 ** Whether or not an error occurs when it is opened, resources
2339 ** associated with the [database connection] handle should be released by
2340 ** passing it to [sqlite3_close()] when it is no longer required.
2341 **
2342 ** The sqlite3_open_v2() interface works like sqlite3_open()
2343 ** except that it accepts two additional parameters for additional control
2344 ** over the new database connection. ^(The flags parameter to
2345 ** sqlite3_open_v2() can take one of
2346 ** the following three values, optionally combined with the
2347 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2348 ** and/or [SQLITE_OPEN_PRIVATECACHE] flags:)^
2349 **
2350 ** <dl>
2351 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2352 ** <dd>The database is opened in read-only mode. If the database does not
2353 ** already exist, an error is returned.</dd>)^
2354 **
2355 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2356 ** <dd>The database is opened for reading and writing if possible, or reading
2357 ** only if the file is write protected by the operating system. In either
2358 ** case the database must already exist, otherwise an error is returned.</dd>)^
2359 **
2360 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2361 ** <dd>The database is opened for reading and writing, and is created if
2362 ** it does not already exist. This is the behavior that is always used for
2363 ** sqlite3_open() and sqlite3_open16().</dd>)^
2364 ** </dl>
2365 **
2366 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
2367 ** combinations shown above or one of the combinations shown above combined
2368 ** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX],
2369 ** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_PRIVATECACHE] flags,
2370 ** then the behavior is undefined.
2371 **
2372 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2373 ** opens in the multi-thread [threading mode] as long as the single-thread
2374 ** mode has not been set at compile-time or start-time. ^If the
2375 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2376 ** in the serialized [threading mode] unless single-thread was
2377 ** previously selected at compile-time or start-time.
2378 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2379 ** eligible to use [shared cache mode], regardless of whether or not shared
2380 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
2381 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2382 ** participate in [shared cache mode] even if it is enabled.
2383 **
2384 ** ^If the filename is ":memory:", then a private, temporary in-memory database
2385 ** is created for the connection. ^This in-memory database will vanish when
2386 ** the database connection is closed. Future versions of SQLite might
2387 ** make use of additional special filenames that begin with the ":" character.
2388 ** It is recommended that when a database filename actually does begin with
2389 ** a ":" character you should prefix the filename with a pathname such as
2390 ** "./" to avoid ambiguity.
2391 **
2392 ** ^If the filename is an empty string, then a private, temporary
2393 ** on-disk database will be created. ^This private database will be
2394 ** automatically deleted as soon as the database connection is closed.
2395 **
2396 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
2397 ** [sqlite3_vfs] object that defines the operating system interface that
2398 ** the new database connection should use. ^If the fourth parameter is
2399 ** a NULL pointer then the default [sqlite3_vfs] object is used.
2400 **
2401 ** <b>Note to Windows users:</b> The encoding used for the filename argument
2402 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2403 ** codepage is currently defined. Filenames containing international
2404 ** characters must be converted to UTF-8 prior to passing them into
2405 ** sqlite3_open() or sqlite3_open_v2().
2406 */
2410 );
2414 );
2420 );
2422 /*
2423 ** CAPI3REF: Error Codes And Messages
2424 **
2425 ** ^The sqlite3_errcode() interface returns the numeric [result code] or
2426 ** [extended result code] for the most recent failed sqlite3_* API call
2427 ** associated with a [database connection]. If a prior API call failed
2428 ** but the most recent API call succeeded, the return value from
2429 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode()
2430 ** interface is the same except that it always returns the
2431 ** [extended result code] even when extended result codes are
2432 ** disabled.
2433 **
2434 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
2435 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
2436 ** ^(Memory to hold the error message string is managed internally.
2437 ** The application does not need to worry about freeing the result.
2438 ** However, the error string might be overwritten or deallocated by
2439 ** subsequent calls to other SQLite interface functions.)^
2440 **
2441 ** When the serialized [threading mode] is in use, it might be the
2442 ** case that a second error occurs on a separate thread in between
2443 ** the time of the first error and the call to these interfaces.
2444 ** When that happens, the second error will be reported since these
2445 ** interfaces always report the most recent result. To avoid
2446 ** this, each thread can obtain exclusive use of the [database connection] D
2447 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
2448 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
2449 ** all calls to the interfaces listed here are completed.
2450 **
2451 ** If an interface fails with SQLITE_MISUSE, that means the interface
2452 ** was invoked incorrectly by the application. In that case, the
2453 ** error code and message may or may not be set.
2454 */
2460 /*
2461 ** CAPI3REF: SQL Statement Object
2462 ** KEYWORDS: {prepared statement} {prepared statements}
2463 **
2464 ** An instance of this object represents a single SQL statement.
2465 ** This object is variously known as a "prepared statement" or a
2466 ** "compiled SQL statement" or simply as a "statement".
2467 **
2468 ** The life of a statement object goes something like this:
2469 **
2470 ** <ol>
2471 ** <li> Create the object using [sqlite3_prepare_v2()] or a related
2472 ** function.
2473 ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
2474 ** interfaces.
2475 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
2476 ** <li> Reset the statement using [sqlite3_reset()] then go back
2477 ** to step 2. Do this zero or more times.
2478 ** <li> Destroy the object using [sqlite3_finalize()].
2479 ** </ol>
2480 **
2481 ** Refer to documentation on individual methods above for additional
2482 ** information.
2483 */
2486 /*
2487 ** CAPI3REF: Run-time Limits
2488 **
2489 ** ^(This interface allows the size of various constructs to be limited
2490 ** on a connection by connection basis. The first parameter is the
2491 ** [database connection] whose limit is to be set or queried. The
2492 ** second parameter is one of the [limit categories] that define a
2493 ** class of constructs to be size limited. The third parameter is the
2494 ** new limit for that construct.)^
2495 **
2496 ** ^If the new limit is a negative number, the limit is unchanged.
2497 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
2498 ** [limits | hard upper bound]
2499 ** set at compile-time by a C preprocessor macro called
2500 ** [limits | SQLITE_MAX_<i>NAME</i>].
2501 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
2502 ** ^Attempts to increase a limit above its hard upper bound are
2503 ** silently truncated to the hard upper bound.
2504 **
2505 ** ^Regardless of whether or not the limit was changed, the
2506 ** [sqlite3_limit()] interface returns the prior value of the limit.
2507 ** ^Hence, to find the current value of a limit without changing it,
2508 ** simply invoke this interface with the third parameter set to -1.
2509 **
2510 ** Run-time limits are intended for use in applications that manage
2511 ** both their own internal database and also databases that are controlled
2512 ** by untrusted external sources. An example application might be a
2513 ** web browser that has its own databases for storing history and
2514 ** separate databases controlled by JavaScript applications downloaded
2515 ** off the Internet. The internal databases can be given the
2516 ** large, default limits. Databases managed by external sources can
2517 ** be given much smaller limits designed to prevent a denial of service
2518 ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
2519 ** interface to further control untrusted SQL. The size of the database
2520 ** created by an untrusted script can be contained using the
2521 ** [max_page_count] [PRAGMA].
2522 **
2523 ** New run-time limit categories may be added in future releases.
2524 */
2527 /*
2528 ** CAPI3REF: Run-Time Limit Categories
2529 ** KEYWORDS: {limit category} {*limit categories}
2530 **
2531 ** These constants define various performance limits
2532 ** that can be lowered at run-time using [sqlite3_limit()].
2533 ** The synopsis of the meanings of the various limits is shown below.
2534 ** Additional information is available at [limits | Limits in SQLite].
2535 **
2536 ** <dl>
2537 ** ^(<dt>SQLITE_LIMIT_LENGTH</dt>
2538 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
2539 **
2540 ** ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
2541 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
2542 **
2543 ** ^(<dt>SQLITE_LIMIT_COLUMN</dt>
2544 ** <dd>The maximum number of columns in a table definition or in the
2545 ** result set of a [SELECT] or the maximum number of columns in an index
2546 ** or in an ORDER BY or GROUP BY clause.</dd>)^
2547 **
2548 ** ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
2549 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
2550 **
2551 ** ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
2552 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
2553 **
2554 ** ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
2555 ** <dd>The maximum number of instructions in a virtual machine program
2556 ** used to implement an SQL statement. This limit is not currently
2557 ** enforced, though that might be added in some future release of
2558 ** SQLite.</dd>)^
2559 **
2560 ** ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
2561 ** <dd>The maximum number of arguments on a function.</dd>)^
2562 **
2563 ** ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
2564 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
2565 **
2566 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
2567 ** <dd>The maximum length of the pattern argument to the [LIKE] or
2568 ** [GLOB] operators.</dd>)^
2569 **
2570 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
2571 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
2572 **
2573 ** ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
2574 ** <dd>The maximum depth of recursion for triggers.</dd>)^
2575 ** </dl>
2576 */
2577 #define SQLITE_LIMIT_LENGTH 0
2578 #define SQLITE_LIMIT_SQL_LENGTH 1
2579 #define SQLITE_LIMIT_COLUMN 2
2580 #define SQLITE_LIMIT_EXPR_DEPTH 3
2581 #define SQLITE_LIMIT_COMPOUND_SELECT 4
2582 #define SQLITE_LIMIT_VDBE_OP 5
2583 #define SQLITE_LIMIT_FUNCTION_ARG 6
2584 #define SQLITE_LIMIT_ATTACHED 7
2585 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
2586 #define SQLITE_LIMIT_VARIABLE_NUMBER 9
2587 #define SQLITE_LIMIT_TRIGGER_DEPTH 10
2589 /*
2590 ** CAPI3REF: Compiling An SQL Statement
2591 ** KEYWORDS: {SQL statement compiler}
2592 **
2593 ** To execute an SQL query, it must first be compiled into a byte-code
2594 ** program using one of these routines.
2595 **
2596 ** The first argument, "db", is a [database connection] obtained from a
2597 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
2598 ** [sqlite3_open16()]. The database connection must not have been closed.
2599 **
2600 ** The second argument, "zSql", is the statement to be compiled, encoded
2601 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
2602 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
2603 ** use UTF-16.
2604 **
2605 ** ^If the nByte argument is less than zero, then zSql is read up to the
2606 ** first zero terminator. ^If nByte is non-negative, then it is the maximum
2607 ** number of bytes read from zSql. ^When nByte is non-negative, the
2608 ** zSql string ends at either the first '\000' or '\u0000' character or
2609 ** the nByte-th byte, whichever comes first. If the caller knows
2610 ** that the supplied string is nul-terminated, then there is a small
2611 ** performance advantage to be gained by passing an nByte parameter that
2612 ** is equal to the number of bytes in the input string <i>including</i>
2613 ** the nul-terminator bytes.
2614 **
2615 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
2616 ** past the end of the first SQL statement in zSql. These routines only
2617 ** compile the first statement in zSql, so *pzTail is left pointing to
2618 ** what remains uncompiled.
2619 **
2620 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
2621 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
2622 ** to NULL. ^If the input text contains no SQL (if the input is an empty
2623 ** string or a comment) then *ppStmt is set to NULL.
2624 ** The calling procedure is responsible for deleting the compiled
2625 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
2626 ** ppStmt may not be NULL.
2627 **
2628 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
2629 ** otherwise an [error code] is returned.
2630 **
2631 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
2632 ** recommended for all new programs. The two older interfaces are retained
2633 ** for backwards compatibility, but their use is discouraged.
2634 ** ^In the "v2" interfaces, the prepared statement
2635 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
2636 ** original SQL text. This causes the [sqlite3_step()] interface to
2637 ** behave differently in three ways:
2638 **
2639 ** <ol>
2640 ** <li>
2641 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
2642 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
2643 ** statement and try to run it again.
2644 ** </li>
2645 **
2646 ** <li>
2647 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
2648 ** [error codes] or [extended error codes]. ^The legacy behavior was that
2649 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
2650 ** and the application would have to make a second call to [sqlite3_reset()]
2651 ** in order to find the underlying cause of the problem. With the "v2" prepare
2652 ** interfaces, the underlying reason for the error is returned immediately.
2653 ** </li>
2654 **
2655 ** <li>
2656 ** ^If the specific value bound to [parameter | host parameter] in the
2657 ** WHERE clause might influence the choice of query plan for a statement,
2658 ** then the statement will be automatically recompiled, as if there had been
2659 ** a schema change, on the first [sqlite3_step()] call following any change
2660 ** to the [sqlite3_bind_text | bindings] of that [parameter].
2661 ** ^The specific value of WHERE-clause [parameter] might influence the
2662 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
2663 ** or [GLOB] operator or if the parameter is compared to an indexed column
2664 ** and the [SQLITE_ENABLE_STAT2] compile-time option is enabled.
2665 ** the
2666 ** </li>
2667 ** </ol>
2668 */
2675 );
2682 );
2689 );
2696 );
2698 /*
2699 ** CAPI3REF: Retrieving Statement SQL
2700 **
2701 ** ^This interface can be used to retrieve a saved copy of the original
2702 ** SQL text used to create a [prepared statement] if that statement was
2703 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
2704 */
2707 /*
2708 ** CAPI3REF: Determine If An SQL Statement Writes The Database
2709 **
2710 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
2711 ** and only if the [prepared statement] X makes no direct changes to
2712 ** the content of the database file.
2713 **
2714 ** Note that [application-defined SQL functions] or
2715 ** [virtual tables] might change the database indirectly as a side effect.
2716 ** ^(For example, if an application defines a function "eval()" that
2717 ** calls [sqlite3_exec()], then the following SQL statement would
2718 ** change the database file through side-effects:
2719 **
2720 ** <blockquote><pre>
2721 ** SELECT eval('DELETE FROM t1') FROM t2;
2722 ** </pre></blockquote>
2723 **
2724 ** But because the [SELECT] statement does not change the database file
2725 ** directly, sqlite3_stmt_readonly() would still return true.)^
2726 **
2727 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
2728 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
2729 ** since the statements themselves do not actually modify the database but
2730 ** rather they control the timing of when other statements modify the
2731 ** database. ^The [ATTACH] and [DETACH] statements also cause
2732 ** sqlite3_stmt_readonly() to return true since, while those statements
2733 ** change the configuration of a database connection, they do not make
2734 ** changes to the content of the database files on disk.
2735 */
2738 /*
2739 ** CAPI3REF: Dynamically Typed Value Object
2740 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
2741 **
2742 ** SQLite uses the sqlite3_value object to represent all values
2743 ** that can be stored in a database table. SQLite uses dynamic typing
2744 ** for the values it stores. ^Values stored in sqlite3_value objects
2745 ** can be integers, floating point values, strings, BLOBs, or NULL.
2746 **
2747 ** An sqlite3_value object may be either "protected" or "unprotected".
2748 ** Some interfaces require a protected sqlite3_value. Other interfaces
2749 ** will accept either a protected or an unprotected sqlite3_value.
2750 ** Every interface that accepts sqlite3_value arguments specifies
2751 ** whether or not it requires a protected sqlite3_value.
2752 **
2753 ** The terms "protected" and "unprotected" refer to whether or not
2754 ** a mutex is held. An internal mutex is held for a protected
2755 ** sqlite3_value object but no mutex is held for an unprotected
2756 ** sqlite3_value object. If SQLite is compiled to be single-threaded
2757 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
2758 ** or if SQLite is run in one of reduced mutex modes
2759 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
2760 ** then there is no distinction between protected and unprotected
2761 ** sqlite3_value objects and they can be used interchangeably. However,
2762 ** for maximum code portability it is recommended that applications
2763 ** still make the distinction between protected and unprotected
2764 ** sqlite3_value objects even when not strictly required.
2765 **
2766 ** ^The sqlite3_value objects that are passed as parameters into the
2767 ** implementation of [application-defined SQL functions] are protected.
2768 ** ^The sqlite3_value object returned by
2769 ** [sqlite3_column_value()] is unprotected.
2770 ** Unprotected sqlite3_value objects may only be used with
2771 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
2772 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
2773 ** interfaces require protected sqlite3_value objects.
2774 */
2777 /*
2778 ** CAPI3REF: SQL Function Context Object
2779 **
2780 ** The context in which an SQL function executes is stored in an
2781 ** sqlite3_context object. ^A pointer to an sqlite3_context object
2782 ** is always first parameter to [application-defined SQL functions].
2783 ** The application-defined SQL function implementation will pass this
2784 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
2785 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
2786 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
2787 ** and/or [sqlite3_set_auxdata()].
2788 */
2791 /*
2792 ** CAPI3REF: Binding Values To Prepared Statements
2793 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
2794 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
2795 **
2796 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
2797 ** literals may be replaced by a [parameter] that matches one of following
2798 ** templates:
2799 **
2800 ** <ul>
2801 ** <li> ?
2802 ** <li> ?NNN
2803 ** <li> :VVV
2804 ** <li> @VVV
2805 ** <li> $VVV
2806 ** </ul>
2807 **
2808 ** In the templates above, NNN represents an integer literal,
2809 ** and VVV represents an alphanumeric identifier.)^ ^The values of these
2810 ** parameters (also called "host parameter names" or "SQL parameters")
2811 ** can be set using the sqlite3_bind_*() routines defined here.
2812 **
2813 ** ^The first argument to the sqlite3_bind_*() routines is always
2814 ** a pointer to the [sqlite3_stmt] object returned from
2815 ** [sqlite3_prepare_v2()] or its variants.
2816 **
2817 ** ^The second argument is the index of the SQL parameter to be set.
2818 ** ^The leftmost SQL parameter has an index of 1. ^When the same named
2819 ** SQL parameter is used more than once, second and subsequent
2820 ** occurrences have the same index as the first occurrence.
2821 ** ^The index for named parameters can be looked up using the
2822 ** [sqlite3_bind_parameter_index()] API if desired. ^The index
2823 ** for "?NNN" parameters is the value of NNN.
2824 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
2825 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
2826 **
2827 ** ^The third argument is the value to bind to the parameter.
2828 **
2829 ** ^(In those routines that have a fourth argument, its value is the
2830 ** number of bytes in the parameter. To be clear: the value is the
2831 ** number of <u>bytes</u> in the value, not the number of characters.)^
2832 ** ^If the fourth parameter is negative, the length of the string is
2833 ** the number of bytes up to the first zero terminator.
2834 **
2835 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
2836 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
2837 ** string after SQLite has finished with it. ^The destructor is called
2838 ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(),
2839 ** sqlite3_bind_text(), or sqlite3_bind_text16() fails.
2840 ** ^If the fifth argument is
2841 ** the special value [SQLITE_STATIC], then SQLite assumes that the
2842 ** information is in static, unmanaged space and does not need to be freed.
2843 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
2844 ** SQLite makes its own private copy of the data immediately, before
2845 ** the sqlite3_bind_*() routine returns.
2846 **
2847 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
2848 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
2849 ** (just an integer to hold its size) while it is being processed.
2850 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
2851 ** content is later written using
2852 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
2853 ** ^A negative value for the zeroblob results in a zero-length BLOB.
2854 **
2855 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
2856 ** for the [prepared statement] or with a prepared statement for which
2857 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
2858 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
2859 ** routine is passed a [prepared statement] that has been finalized, the
2860 ** result is undefined and probably harmful.
2861 **
2862 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
2863 ** ^Unbound parameters are interpreted as NULL.
2864 **
2865 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
2866 ** [error code] if anything goes wrong.
2867 ** ^[SQLITE_RANGE] is returned if the parameter
2868 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
2869 **
2870 ** See also: [sqlite3_bind_parameter_count()],
2871 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
2872 */
2883 /*
2884 ** CAPI3REF: Number Of SQL Parameters
2885 **
2886 ** ^This routine can be used to find the number of [SQL parameters]
2887 ** in a [prepared statement]. SQL parameters are tokens of the
2888 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
2889 ** placeholders for values that are [sqlite3_bind_blob | bound]
2890 ** to the parameters at a later time.
2891 **
2892 ** ^(This routine actually returns the index of the largest (rightmost)
2893 ** parameter. For all forms except ?NNN, this will correspond to the
2894 ** number of unique parameters. If parameters of the ?NNN form are used,
2895 ** there may be gaps in the list.)^
2896 **
2897 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
2898 ** [sqlite3_bind_parameter_name()], and
2899 ** [sqlite3_bind_parameter_index()].
2900 */
2903 /*
2904 ** CAPI3REF: Name Of A Host Parameter
2905 **
2906 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
2907 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
2908 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
2909 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
2910 ** respectively.
2911 ** In other words, the initial ":" or "$" or "@" or "?"
2912 ** is included as part of the name.)^
2913 ** ^Parameters of the form "?" without a following integer have no name
2914 ** and are referred to as "nameless" or "anonymous parameters".
2915 **
2916 ** ^The first host parameter has an index of 1, not 0.
2917 **
2918 ** ^If the value N is out of range or if the N-th parameter is
2919 ** nameless, then NULL is returned. ^The returned string is
2920 ** always in UTF-8 encoding even if the named parameter was
2921 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
2922 ** [sqlite3_prepare16_v2()].
2923 **
2924 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
2925 ** [sqlite3_bind_parameter_count()], and
2926 ** [sqlite3_bind_parameter_index()].
2927 */
2930 /*
2931 ** CAPI3REF: Index Of A Parameter With A Given Name
2932 **
2933 ** ^Return the index of an SQL parameter given its name. ^The
2934 ** index value returned is suitable for use as the second
2935 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
2936 ** is returned if no matching parameter is found. ^The parameter
2937 ** name must be given in UTF-8 even if the original statement
2938 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
2939 **
2940 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
2941 ** [sqlite3_bind_parameter_count()], and
2942 ** [sqlite3_bind_parameter_index()].
2943 */
2946 /*
2947 ** CAPI3REF: Reset All Bindings On A Prepared Statement
2948 **
2949 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
2950 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
2951 ** ^Use this routine to reset all host parameters to NULL.
2952 */
2955 /*
2956 ** CAPI3REF: Number Of Columns In A Result Set
2957 **
2958 ** ^Return the number of columns in the result set returned by the
2959 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
2960 ** statement that does not return data (for example an [UPDATE]).
2961 **
2962 ** See also: [sqlite3_data_count()]
2963 */
2966 /*
2967 ** CAPI3REF: Column Names In A Result Set
2968 **
2969 ** ^These routines return the name assigned to a particular column
2970 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
2971 ** interface returns a pointer to a zero-terminated UTF-8 string
2972 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
2973 ** UTF-16 string. ^The first parameter is the [prepared statement]
2974 ** that implements the [SELECT] statement. ^The second parameter is the
2975 ** column number. ^The leftmost column is number 0.
2976 **
2977 ** ^The returned string pointer is valid until either the [prepared statement]
2978 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
2979 ** reprepared by the first call to [sqlite3_step()] for a particular run
2980 ** or until the next call to
2981 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
2982 **
2983 ** ^If sqlite3_malloc() fails during the processing of either routine
2984 ** (for example during a conversion from UTF-8 to UTF-16) then a
2985 ** NULL pointer is returned.
2986 **
2987 ** ^The name of a result column is the value of the "AS" clause for
2988 ** that column, if there is an AS clause. If there is no AS clause
2989 ** then the name of the column is unspecified and may change from
2990 ** one release of SQLite to the next.
2991 */
2995 /*
2996 ** CAPI3REF: Source Of Data In A Query Result
2997 **
2998 ** ^These routines provide a means to determine the database, table, and
2999 ** table column that is the origin of a particular result column in
3000 ** [SELECT] statement.
3001 ** ^The name of the database or table or column can be returned as
3002 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
3003 ** the database name, the _table_ routines return the table name, and
3004 ** the origin_ routines return the column name.
3005 ** ^The returned string is valid until the [prepared statement] is destroyed
3006 ** using [sqlite3_finalize()] or until the statement is automatically
3007 ** reprepared by the first call to [sqlite3_step()] for a particular run
3008 ** or until the same information is requested
3009 ** again in a different encoding.
3010 **
3011 ** ^The names returned are the original un-aliased names of the
3012 ** database, table, and column.
3013 **
3014 ** ^The first argument to these interfaces is a [prepared statement].
3015 ** ^These functions return information about the Nth result column returned by
3016 ** the statement, where N is the second function argument.
3017 ** ^The left-most column is column 0 for these routines.
3018 **
3019 ** ^If the Nth column returned by the statement is an expression or
3020 ** subquery and is not a column value, then all of these functions return
3021 ** NULL. ^These routine might also return NULL if a memory allocation error
3022 ** occurs. ^Otherwise, they return the name of the attached database, table,
3023 ** or column that query result column was extracted from.
3024 **
3025 ** ^As with all other SQLite APIs, those whose names end with "16" return
3026 ** UTF-16 encoded strings and the other functions return UTF-8.
3027 **
3028 ** ^These APIs are only available if the library was compiled with the
3029 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3030 **
3031 ** If two or more threads call one or more of these routines against the same
3032 ** prepared statement and column at the same time then the results are
3033 ** undefined.
3034 **
3035 ** If two or more threads call one or more
3036 ** [sqlite3_column_database_name | column metadata interfaces]
3037 ** for the same [prepared statement] and result column
3038 ** at the same time then the results are undefined.
3039 */
3047 /*
3048 ** CAPI3REF: Declared Datatype Of A Query Result
3049 **
3050 ** ^(The first parameter is a [prepared statement].
3051 ** If this statement is a [SELECT] statement and the Nth column of the
3052 ** returned result set of that [SELECT] is a table column (not an
3053 ** expression or subquery) then the declared type of the table
3054 ** column is returned.)^ ^If the Nth column of the result set is an
3055 ** expression or subquery, then a NULL pointer is returned.
3056 ** ^The returned string is always UTF-8 encoded.
3057 **
3058 ** ^(For example, given the database schema:
3059 **
3060 ** CREATE TABLE t1(c1 VARIANT);
3061 **
3062 ** and the following statement to be compiled:
3063 **
3064 ** SELECT c1 + 1, c1 FROM t1;
3065 **
3066 ** this routine would return the string "VARIANT" for the second result
3067 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
3068 **
3069 ** ^SQLite uses dynamic run-time typing. ^So just because a column
3070 ** is declared to contain a particular type does not mean that the
3071 ** data stored in that column is of the declared type. SQLite is
3072 ** strongly typed, but the typing is dynamic not static. ^Type
3073 ** is associated with individual values, not with the containers
3074 ** used to hold those values.
3075 */
3079 /*
3080 ** CAPI3REF: Evaluate An SQL Statement
3081 **
3082 ** After a [prepared statement] has been prepared using either
3083 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3084 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3085 ** must be called one or more times to evaluate the statement.
3086 **
3087 ** The details of the behavior of the sqlite3_step() interface depend
3088 ** on whether the statement was prepared using the newer "v2" interface
3089 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3090 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
3091 ** new "v2" interface is recommended for new applications but the legacy
3092 ** interface will continue to be supported.
3093 **
3094 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3095 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3096 ** ^With the "v2" interface, any of the other [result codes] or
3097 ** [extended result codes] might be returned as well.
3098 **
3099 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3100 ** database locks it needs to do its job. ^If the statement is a [COMMIT]
3101 ** or occurs outside of an explicit transaction, then you can retry the
3102 ** statement. If the statement is not a [COMMIT] and occurs within a
3103 ** explicit transaction then you should rollback the transaction before
3104 ** continuing.
3105 **
3106 ** ^[SQLITE_DONE] means that the statement has finished executing
3107 ** successfully. sqlite3_step() should not be called again on this virtual
3108 ** machine without first calling [sqlite3_reset()] to reset the virtual
3109 ** machine back to its initial state.
3110 **
3111 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3112 ** is returned each time a new row of data is ready for processing by the
3113 ** caller. The values may be accessed using the [column access functions].
3114 ** sqlite3_step() is called again to retrieve the next row of data.
3115 **
3116 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3117 ** violation) has occurred. sqlite3_step() should not be called again on
3118 ** the VM. More information may be found by calling [sqlite3_errmsg()].
3119 ** ^With the legacy interface, a more specific error code (for example,
3120 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3121 ** can be obtained by calling [sqlite3_reset()] on the
3122 ** [prepared statement]. ^In the "v2" interface,
3123 ** the more specific error code is returned directly by sqlite3_step().
3124 **
3125 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3126 ** Perhaps it was called on a [prepared statement] that has
3127 ** already been [sqlite3_finalize | finalized] or on one that had
3128 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
3129 ** be the case that the same database connection is being used by two or
3130 ** more threads at the same moment in time.
3131 **
3132 ** For all versions of SQLite up to and including 3.6.23.1, a call to
3133 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
3134 ** other than [SQLITE_ROW] before any subsequent invocation of
3135 ** sqlite3_step(). Failure to reset the prepared statement using
3136 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3137 ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began
3138 ** calling [sqlite3_reset()] automatically in this circumstance rather
3139 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
3140 ** break because any application that ever receives an SQLITE_MISUSE error
3141 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
3142 ** can be used to restore the legacy behavior.
3143 **
3144 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3145 ** API always returns a generic error code, [SQLITE_ERROR], following any
3146 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
3147 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3148 ** specific [error codes] that better describes the error.
3149 ** We admit that this is a goofy design. The problem has been fixed
3150 ** with the "v2" interface. If you prepare all of your SQL statements
3151 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3152 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3153 ** then the more specific [error codes] are returned directly
3154 ** by sqlite3_step(). The use of the "v2" interface is recommended.
3155 */
3158 /*
3159 ** CAPI3REF: Number of columns in a result set
3160 **
3161 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
3162 ** current row of the result set of [prepared statement] P.
3163 ** ^If prepared statement P does not have results ready to return
3164 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3165 ** interfaces) then sqlite3_data_count(P) returns 0.
3166 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3167 **
3168 ** See also: [sqlite3_column_count()]
3169 */
3172 /*
3173 ** CAPI3REF: Fundamental Datatypes
3174 ** KEYWORDS: SQLITE_TEXT
3175 **
3176 ** ^(Every value in SQLite has one of five fundamental datatypes:
3177 **
3178 ** <ul>
3179 ** <li> 64-bit signed integer
3180 ** <li> 64-bit IEEE floating point number
3181 ** <li> string
3182 ** <li> BLOB
3183 ** <li> NULL
3184 ** </ul>)^
3185 **
3186 ** These constants are codes for each of those types.
3187 **
3188 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3189 ** for a completely different meaning. Software that links against both
3190 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3191 ** SQLITE_TEXT.
3192 */
3193 #define SQLITE_INTEGER 1
3194 #define SQLITE_FLOAT 2
3195 #define SQLITE_BLOB 4
3196 #define SQLITE_NULL 5
3197 #ifdef SQLITE_TEXT
3198 # undef SQLITE_TEXT
3199 #else
3200 # define SQLITE_TEXT 3
3201 #endif
3202 #define SQLITE3_TEXT 3
3204 /*
3205 ** CAPI3REF: Result Values From A Query
3206 ** KEYWORDS: {column access functions}
3207 **
3208 ** These routines form the "result set" interface.
3209 **
3210 ** ^These routines return information about a single column of the current
3211 ** result row of a query. ^In every case the first argument is a pointer
3212 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3213 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3214 ** and the second argument is the index of the column for which information
3215 ** should be returned. ^The leftmost column of the result set has the index 0.
3216 ** ^The number of columns in the result can be determined using
3217 ** [sqlite3_column_count()].
3218 **
3219 ** If the SQL statement does not currently point to a valid row, or if the
3220 ** column index is out of range, the result is undefined.
3221 ** These routines may only be called when the most recent call to
3222 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3223 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3224 ** If any of these routines are called after [sqlite3_reset()] or
3225 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3226 ** something other than [SQLITE_ROW], the results are undefined.
3227 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3228 ** are called from a different thread while any of these routines
3229 ** are pending, then the results are undefined.
3230 **
3231 ** ^The sqlite3_column_type() routine returns the
3232 ** [SQLITE_INTEGER | datatype code] for the initial data type
3233 ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
3234 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
3235 ** returned by sqlite3_column_type() is only meaningful if no type
3236 ** conversions have occurred as described below. After a type conversion,
3237 ** the value returned by sqlite3_column_type() is undefined. Future
3238 ** versions of SQLite may change the behavior of sqlite3_column_type()
3239 ** following a type conversion.
3240 **
3241 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3242 ** routine returns the number of bytes in that BLOB or string.
3243 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3244 ** the string to UTF-8 and then returns the number of bytes.
3245 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
3246 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3247 ** the number of bytes in that string.
3248 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3249 **
3250 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3251 ** routine returns the number of bytes in that BLOB or string.
3252 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3253 ** the string to UTF-16 and then returns the number of bytes.
3254 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3255 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3256 ** the number of bytes in that string.
3257 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3258 **
3259 ** ^The values returned by [sqlite3_column_bytes()] and
3260 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3261 ** of the string. ^For clarity: the values returned by
3262 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3263 ** bytes in the string, not the number of characters.
3264 **
3265 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3266 ** even empty strings, are always zero terminated. ^The return
3267 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3268 **
3269 ** ^The object returned by [sqlite3_column_value()] is an
3270 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object
3271 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
3272 ** If the [unprotected sqlite3_value] object returned by
3273 ** [sqlite3_column_value()] is used in any other way, including calls
3274 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3275 ** or [sqlite3_value_bytes()], then the behavior is undefined.
3276 **
3277 ** These routines attempt to convert the value where appropriate. ^For
3278 ** example, if the internal representation is FLOAT and a text result
3279 ** is requested, [sqlite3_snprintf()] is used internally to perform the
3280 ** conversion automatically. ^(The following table details the conversions
3281 ** that are applied:
3282 **
3283 ** <blockquote>
3284 ** <table border="1">
3285 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
3286 **
3287 ** <tr><td> NULL <td> INTEGER <td> Result is 0
3288 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
3289 ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer
3290 ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer
3291 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
3292 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
3293 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
3294 ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer
3295 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
3296 ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT
3297 ** <tr><td> TEXT <td> INTEGER <td> Use atoi()
3298 ** <tr><td> TEXT <td> FLOAT <td> Use atof()
3299 ** <tr><td> TEXT <td> BLOB <td> No change
3300 ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi()
3301 ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof()
3302 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
3303 ** </table>
3304 ** </blockquote>)^
3305 **
3306 ** The table above makes reference to standard C library functions atoi()
3307 ** and atof(). SQLite does not really use these functions. It has its
3308 ** own equivalent internal routines. The atoi() and atof() names are
3309 ** used in the table for brevity and because they are familiar to most
3310 ** C programmers.
3311 **
3312 ** Note that when type conversions occur, pointers returned by prior
3313 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
3314 ** sqlite3_column_text16() may be invalidated.
3315 ** Type conversions and pointer invalidations might occur
3316 ** in the following cases:
3317 **
3318 ** <ul>
3319 ** <li> The initial content is a BLOB and sqlite3_column_text() or
3320 ** sqlite3_column_text16() is called. A zero-terminator might
3321 ** need to be added to the string.</li>
3322 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
3323 ** sqlite3_column_text16() is called. The content must be converted
3324 ** to UTF-16.</li>
3325 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
3326 ** sqlite3_column_text() is called. The content must be converted
3327 ** to UTF-8.</li>
3328 ** </ul>
3329 **
3330 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
3331 ** not invalidate a prior pointer, though of course the content of the buffer
3332 ** that the prior pointer references will have been modified. Other kinds
3333 ** of conversion are done in place when it is possible, but sometimes they
3334 ** are not possible and in those cases prior pointers are invalidated.
3335 **
3336 ** The safest and easiest to remember policy is to invoke these routines
3337 ** in one of the following ways:
3338 **
3339 ** <ul>
3340 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
3341 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
3342 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
3343 ** </ul>
3344 **
3345 ** In other words, you should call sqlite3_column_text(),
3346 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
3347 ** into the desired format, then invoke sqlite3_column_bytes() or
3348 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
3349 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
3350 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
3351 ** with calls to sqlite3_column_bytes().
3352 **
3353 ** ^The pointers returned are valid until a type conversion occurs as
3354 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
3355 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
3356 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned
3357 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
3358 ** [sqlite3_free()].
3359 **
3360 ** ^(If a memory allocation error occurs during the evaluation of any
3361 ** of these routines, a default value is returned. The default value
3362 ** is either the integer 0, the floating point number 0.0, or a NULL
3363 ** pointer. Subsequent calls to [sqlite3_errcode()] will return
3364 ** [SQLITE_NOMEM].)^
3365 */
3377 /*
3378 ** CAPI3REF: Destroy A Prepared Statement Object
3379 **
3380 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
3381 ** ^If the most recent evaluation of the statement encountered no errors or
3382 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
3383 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
3384 ** sqlite3_finalize(S) returns the appropriate [error code] or
3385 ** [extended error code].
3386 **
3387 ** ^The sqlite3_finalize(S) routine can be called at any point during
3388 ** the life cycle of [prepared statement] S:
3389 ** before statement S is ever evaluated, after
3390 ** one or more calls to [sqlite3_reset()], or after any call
3391 ** to [sqlite3_step()] regardless of whether or not the statement has
3392 ** completed execution.
3393 **
3394 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
3395 **
3396 ** The application must finalize every [prepared statement] in order to avoid
3397 ** resource leaks. It is a grievous error for the application to try to use
3398 ** a prepared statement after it has been finalized. Any use of a prepared
3399 ** statement after it has been finalized can result in undefined and
3400 ** undesirable behavior such as segfaults and heap corruption.
3401 */
3404 /*
3405 ** CAPI3REF: Reset A Prepared Statement Object
3406 **
3407 ** The sqlite3_reset() function is called to reset a [prepared statement]
3408 ** object back to its initial state, ready to be re-executed.
3409 ** ^Any SQL statement variables that had values bound to them using
3410 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
3411 ** Use [sqlite3_clear_bindings()] to reset the bindings.
3412 **
3413 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
3414 ** back to the beginning of its program.
3415 **
3416 ** ^If the most recent call to [sqlite3_step(S)] for the
3417 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
3418 ** or if [sqlite3_step(S)] has never before been called on S,
3419 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
3420 **
3421 ** ^If the most recent call to [sqlite3_step(S)] for the
3422 ** [prepared statement] S indicated an error, then
3423 ** [sqlite3_reset(S)] returns an appropriate [error code].
3424 **
3425 ** ^The [sqlite3_reset(S)] interface does not change the values
3426 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
3427 */
3430 /*
3431 ** CAPI3REF: Create Or Redefine SQL Functions
3432 ** KEYWORDS: {function creation routines}
3433 ** KEYWORDS: {application-defined SQL function}
3434 ** KEYWORDS: {application-defined SQL functions}
3435 **
3436 ** ^These functions (collectively known as "function creation routines")
3437 ** are used to add SQL functions or aggregates or to redefine the behavior
3438 ** of existing SQL functions or aggregates. The only differences between
3439 ** these routines are the text encoding expected for
3440 ** the second parameter (the name of the function being created)
3441 ** and the presence or absence of a destructor callback for
3442 ** the application data pointer.
3443 **
3444 ** ^The first parameter is the [database connection] to which the SQL
3445 ** function is to be added. ^If an application uses more than one database
3446 ** connection then application-defined SQL functions must be added
3447 ** to each database connection separately.
3448 **
3449 ** ^The second parameter is the name of the SQL function to be created or
3450 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
3451 ** representation, exclusive of the zero-terminator. ^Note that the name
3452 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
3453 ** ^Any attempt to create a function with a longer name
3454 ** will result in [SQLITE_MISUSE] being returned.
3455 **
3456 ** ^The third parameter (nArg)
3457 ** is the number of arguments that the SQL function or
3458 ** aggregate takes. ^If this parameter is -1, then the SQL function or
3459 ** aggregate may take any number of arguments between 0 and the limit
3460 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
3461 ** parameter is less than -1 or greater than 127 then the behavior is
3462 ** undefined.
3463 **
3464 ** ^The fourth parameter, eTextRep, specifies what
3465 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
3466 ** its parameters. Every SQL function implementation must be able to work
3467 ** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be
3468 ** more efficient with one encoding than another. ^An application may
3469 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
3470 ** times with the same function but with different values of eTextRep.
3471 ** ^When multiple implementations of the same function are available, SQLite
3472 ** will pick the one that involves the least amount of data conversion.
3473 ** If there is only a single implementation which does not care what text
3474 ** encoding is used, then the fourth argument should be [SQLITE_ANY].
3475 **
3476 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
3477 ** function can gain access to this pointer using [sqlite3_user_data()].)^
3478 **
3479 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
3480 ** pointers to C-language functions that implement the SQL function or
3481 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
3482 ** callback only; NULL pointers must be passed as the xStep and xFinal
3483 ** parameters. ^An aggregate SQL function requires an implementation of xStep
3484 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
3485 ** SQL function or aggregate, pass NULL pointers for all three function
3486 ** callbacks.
3487 **
3488 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
3489 ** then it is destructor for the application data pointer.
3490 ** The destructor is invoked when the function is deleted, either by being
3491 ** overloaded or when the database connection closes.)^
3492 ** ^The destructor is also invoked if the call to
3493 ** sqlite3_create_function_v2() fails.
3494 ** ^When the destructor callback of the tenth parameter is invoked, it
3495 ** is passed a single argument which is a copy of the application data
3496 ** pointer which was the fifth parameter to sqlite3_create_function_v2().
3497 **
3498 ** ^It is permitted to register multiple implementations of the same
3499 ** functions with the same name but with either differing numbers of
3500 ** arguments or differing preferred text encodings. ^SQLite will use
3501 ** the implementation that most closely matches the way in which the
3502 ** SQL function is used. ^A function implementation with a non-negative
3503 ** nArg parameter is a better match than a function implementation with
3504 ** a negative nArg. ^A function where the preferred text encoding
3505 ** matches the database encoding is a better
3506 ** match than a function where the encoding is different.
3507 ** ^A function where the encoding difference is between UTF16le and UTF16be
3508 ** is a closer match than a function where the encoding difference is
3509 ** between UTF8 and UTF16.
3510 **
3511 ** ^Built-in functions may be overloaded by new application-defined functions.
3512 **
3513 ** ^An application-defined function is permitted to call other
3514 ** SQLite interfaces. However, such calls must not
3515 ** close the database connection nor finalize or reset the prepared
3516 ** statement in which the function is running.
3517 */
3527 );
3537 );
3548 );
3550 /*
3551 ** CAPI3REF: Text Encodings
3552 **
3553 ** These constant define integer codes that represent the various
3554 ** text encodings supported by SQLite.
3555 */
3556 #define SQLITE_UTF8 1
3557 #define SQLITE_UTF16LE 2
3558 #define SQLITE_UTF16BE 3
3563 /*
3564 ** CAPI3REF: Deprecated Functions
3565 ** DEPRECATED
3566 **
3567 ** These functions are [deprecated]. In order to maintain
3568 ** backwards compatibility with older code, these functions continue
3569 ** to be supported. However, new applications should avoid
3570 ** the use of these functions. To help encourage people to avoid
3571 ** using these functions, we are not going to tell you what they do.
3572 */
3573 #ifndef SQLITE_OMIT_DEPRECATED
3579 SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
3580 #endif
3582 /*
3583 ** CAPI3REF: Obtaining SQL Function Parameter Values
3584 **
3585 ** The C-language implementation of SQL functions and aggregates uses
3586 ** this set of interface routines to access the parameter values on
3587 ** the function or aggregate.
3588 **
3589 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
3590 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
3591 ** define callbacks that implement the SQL functions and aggregates.
3592 ** The 3rd parameter to these callbacks is an array of pointers to
3593 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
3594 ** each parameter to the SQL function. These routines are used to
3595 ** extract values from the [sqlite3_value] objects.
3596 **
3597 ** These routines work only with [protected sqlite3_value] objects.
3598 ** Any attempt to use these routines on an [unprotected sqlite3_value]
3599 ** object results in undefined behavior.
3600 **
3601 ** ^These routines work just like the corresponding [column access functions]
3602 ** except that these routines take a single [protected sqlite3_value] object
3603 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
3604 **
3605 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
3606 ** in the native byte-order of the host machine. ^The
3607 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
3608 ** extract UTF-16 strings as big-endian and little-endian respectively.
3609 **
3610 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
3611 ** numeric affinity to the value. This means that an attempt is
3612 ** made to convert the value to an integer or floating point. If
3613 ** such a conversion is possible without loss of information (in other
3614 ** words, if the value is a string that looks like a number)
3615 ** then the conversion is performed. Otherwise no conversion occurs.
3616 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
3617 **
3618 ** Please pay particular attention to the fact that the pointer returned
3619 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
3620 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
3621 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
3622 ** or [sqlite3_value_text16()].
3623 **
3624 ** These routines must be called from the same thread as
3625 ** the SQL function that supplied the [sqlite3_value*] parameters.
3626 */
3640 /*
3641 ** CAPI3REF: Obtain Aggregate Function Context
3642 **
3643 ** Implementations of aggregate SQL functions use this
3644 ** routine to allocate memory for storing their state.
3645 **
3646 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
3647 ** for a particular aggregate function, SQLite
3648 ** allocates N of memory, zeroes out that memory, and returns a pointer
3649 ** to the new memory. ^On second and subsequent calls to
3650 ** sqlite3_aggregate_context() for the same aggregate function instance,
3651 ** the same buffer is returned. Sqlite3_aggregate_context() is normally
3652 ** called once for each invocation of the xStep callback and then one
3653 ** last time when the xFinal callback is invoked. ^(When no rows match
3654 ** an aggregate query, the xStep() callback of the aggregate function
3655 ** implementation is never called and xFinal() is called exactly once.
3656 ** In those cases, sqlite3_aggregate_context() might be called for the
3657 ** first time from within xFinal().)^
3658 **
3659 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is
3660 ** less than or equal to zero or if a memory allocate error occurs.
3661 **
3662 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
3663 ** determined by the N parameter on first successful call. Changing the
3664 ** value of N in subsequent call to sqlite3_aggregate_context() within
3665 ** the same aggregate function instance will not resize the memory
3666 ** allocation.)^
3667 **
3668 ** ^SQLite automatically frees the memory allocated by
3669 ** sqlite3_aggregate_context() when the aggregate query concludes.
3670 **
3671 ** The first parameter must be a copy of the
3672 ** [sqlite3_context | SQL function context] that is the first parameter
3673 ** to the xStep or xFinal callback routine that implements the aggregate
3674 ** function.
3675 **
3676 ** This routine must be called from the same thread in which
3677 ** the aggregate SQL function is running.
3678 */
3681 /*
3682 ** CAPI3REF: User Data For Functions
3683 **
3684 ** ^The sqlite3_user_data() interface returns a copy of
3685 ** the pointer that was the pUserData parameter (the 5th parameter)
3686 ** of the [sqlite3_create_function()]
3687 ** and [sqlite3_create_function16()] routines that originally
3688 ** registered the application defined function.
3689 **
3690 ** This routine must be called from the same thread in which
3691 ** the application-defined function is running.
3692 */
3695 /*
3696 ** CAPI3REF: Database Connection For Functions
3697 **
3698 ** ^The sqlite3_context_db_handle() interface returns a copy of
3699 ** the pointer to the [database connection] (the 1st parameter)
3700 ** of the [sqlite3_create_function()]
3701 ** and [sqlite3_create_function16()] routines that originally
3702 ** registered the application defined function.
3703 */
3706 /*
3707 ** CAPI3REF: Function Auxiliary Data
3708 **
3709 ** The following two functions may be used by scalar SQL functions to
3710 ** associate metadata with argument values. If the same value is passed to
3711 ** multiple invocations of the same SQL function during query execution, under
3712 ** some circumstances the associated metadata may be preserved. This may
3713 ** be used, for example, to add a regular-expression matching scalar
3714 ** function. The compiled version of the regular expression is stored as
3715 ** metadata associated with the SQL value passed as the regular expression
3716 ** pattern. The compiled regular expression can be reused on multiple
3717 ** invocations of the same function so that the original pattern string
3718 ** does not need to be recompiled on each invocation.
3719 **
3720 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
3721 ** associated by the sqlite3_set_auxdata() function with the Nth argument
3722 ** value to the application-defined function. ^If no metadata has been ever
3723 ** been set for the Nth argument of the function, or if the corresponding
3724 ** function parameter has changed since the meta-data was set,
3725 ** then sqlite3_get_auxdata() returns a NULL pointer.
3726 **
3727 ** ^The sqlite3_set_auxdata() interface saves the metadata
3728 ** pointed to by its 3rd parameter as the metadata for the N-th
3729 ** argument of the application-defined function. Subsequent
3730 ** calls to sqlite3_get_auxdata() might return this data, if it has
3731 ** not been destroyed.
3732 ** ^If it is not NULL, SQLite will invoke the destructor
3733 ** function given by the 4th parameter to sqlite3_set_auxdata() on
3734 ** the metadata when the corresponding function parameter changes
3735 ** or when the SQL statement completes, whichever comes first.
3736 **
3737 ** SQLite is free to call the destructor and drop metadata on any
3738 ** parameter of any function at any time. ^The only guarantee is that
3739 ** the destructor will be called before the metadata is dropped.
3740 **
3741 ** ^(In practice, metadata is preserved between function calls for
3742 ** expressions that are constant at compile time. This includes literal
3743 ** values and [parameters].)^
3744 **
3745 ** These routines must be called from the same thread in which
3746 ** the SQL function is running.
3747 */
3752 /*
3753 ** CAPI3REF: Constants Defining Special Destructor Behavior
3754 **
3755 ** These are special values for the destructor that is passed in as the
3756 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
3757 ** argument is SQLITE_STATIC, it means that the content pointer is constant
3758 ** and will never change. It does not need to be destroyed. ^The
3759 ** SQLITE_TRANSIENT value means that the content will likely change in
3760 ** the near future and that SQLite should make its own private copy of
3761 ** the content before returning.
3762 **
3763 ** The typedef is necessary to work around problems in certain
3764 ** C++ compilers. See ticket #2191.
3765 */
3767 #define SQLITE_STATIC ((sqlite3_destructor_type)0)
3768 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
3770 /*
3771 ** CAPI3REF: Setting The Result Of An SQL Function
3772 **
3773 ** These routines are used by the xFunc or xFinal callbacks that
3774 ** implement SQL functions and aggregates. See
3775 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
3776 ** for additional information.
3777 **
3778 ** These functions work very much like the [parameter binding] family of
3779 ** functions used to bind values to host parameters in prepared statements.
3780 ** Refer to the [SQL parameter] documentation for additional information.
3781 **
3782 ** ^The sqlite3_result_blob() interface sets the result from
3783 ** an application-defined function to be the BLOB whose content is pointed
3784 ** to by the second parameter and which is N bytes long where N is the
3785 ** third parameter.
3786 **
3787 ** ^The sqlite3_result_zeroblob() interfaces set the result of
3788 ** the application-defined function to be a BLOB containing all zero
3789 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
3790 **
3791 ** ^The sqlite3_result_double() interface sets the result from
3792 ** an application-defined function to be a floating point value specified
3793 ** by its 2nd argument.
3794 **
3795 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
3796 ** cause the implemented SQL function to throw an exception.
3797 ** ^SQLite uses the string pointed to by the
3798 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
3799 ** as the text of an error message. ^SQLite interprets the error
3800 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
3801 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
3802 ** byte order. ^If the third parameter to sqlite3_result_error()
3803 ** or sqlite3_result_error16() is negative then SQLite takes as the error
3804 ** message all text up through the first zero character.
3805 ** ^If the third parameter to sqlite3_result_error() or
3806 ** sqlite3_result_error16() is non-negative then SQLite takes that many
3807 ** bytes (not characters) from the 2nd parameter as the error message.
3808 ** ^The sqlite3_result_error() and sqlite3_result_error16()
3809 ** routines make a private copy of the error message text before
3810 ** they return. Hence, the calling function can deallocate or
3811 ** modify the text after they return without harm.
3812 ** ^The sqlite3_result_error_code() function changes the error code
3813 ** returned by SQLite as a result of an error in a function. ^By default,
3814 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
3815 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
3816 **
3817 ** ^The sqlite3_result_toobig() interface causes SQLite to throw an error
3818 ** indicating that a string or BLOB is too long to represent.
3819 **
3820 ** ^The sqlite3_result_nomem() interface causes SQLite to throw an error
3821 ** indicating that a memory allocation failed.
3822 **
3823 ** ^The sqlite3_result_int() interface sets the return value
3824 ** of the application-defined function to be the 32-bit signed integer
3825 ** value given in the 2nd argument.
3826 ** ^The sqlite3_result_int64() interface sets the return value
3827 ** of the application-defined function to be the 64-bit signed integer
3828 ** value given in the 2nd argument.
3829 **
3830 ** ^The sqlite3_result_null() interface sets the return value
3831 ** of the application-defined function to be NULL.
3832 **
3833 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
3834 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
3835 ** set the return value of the application-defined function to be
3836 ** a text string which is represented as UTF-8, UTF-16 native byte order,
3837 ** UTF-16 little endian, or UTF-16 big endian, respectively.
3838 ** ^SQLite takes the text result from the application from
3839 ** the 2nd parameter of the sqlite3_result_text* interfaces.
3840 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
3841 ** is negative, then SQLite takes result text from the 2nd parameter
3842 ** through the first zero character.
3843 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
3844 ** is non-negative, then as many bytes (not characters) of the text
3845 ** pointed to by the 2nd parameter are taken as the application-defined
3846 ** function result.
3847 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
3848 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
3849 ** function as the destructor on the text or BLOB result when it has
3850 ** finished using that result.
3851 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
3852 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
3853 ** assumes that the text or BLOB result is in constant space and does not
3854 ** copy the content of the parameter nor call a destructor on the content
3855 ** when it has finished using that result.
3856 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
3857 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
3858 ** then SQLite makes a copy of the result into space obtained from
3859 ** from [sqlite3_malloc()] before it returns.
3860 **
3861 ** ^The sqlite3_result_value() interface sets the result of
3862 ** the application-defined function to be a copy the
3863 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
3864 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
3865 ** so that the [sqlite3_value] specified in the parameter may change or
3866 ** be deallocated after sqlite3_result_value() returns without harm.
3867 ** ^A [protected sqlite3_value] object may always be used where an
3868 ** [unprotected sqlite3_value] object is required, so either
3869 ** kind of [sqlite3_value] object can be used with this interface.
3870 **
3871 ** If these routines are called from within the different thread
3872 ** than the one containing the application-defined function that received
3873 ** the [sqlite3_context] pointer, the results are undefined.
3874 */
3892 /*
3893 ** CAPI3REF: Define New Collating Sequences
3894 **
3895 ** ^These functions add, remove, or modify a [collation] associated
3896 ** with the [database connection] specified as the first argument.
3897 **
3898 ** ^The name of the collation is a UTF-8 string
3899 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
3900 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
3901 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
3902 ** considered to be the same name.
3903 **
3904 ** ^(The third argument (eTextRep) must be one of the constants:
3905 ** <ul>
3906 ** <li> [SQLITE_UTF8],
3907 ** <li> [SQLITE_UTF16LE],
3908 ** <li> [SQLITE_UTF16BE],
3909 ** <li> [SQLITE_UTF16], or
3910 ** <li> [SQLITE_UTF16_ALIGNED].
3911 ** </ul>)^
3912 ** ^The eTextRep argument determines the encoding of strings passed
3913 ** to the collating function callback, xCallback.
3914 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
3915 ** force strings to be UTF16 with native byte order.
3916 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
3917 ** on an even byte address.
3918 **
3919 ** ^The fourth argument, pArg, is an application data pointer that is passed
3920 ** through as the first argument to the collating function callback.
3921 **
3922 ** ^The fifth argument, xCallback, is a pointer to the collating function.
3923 ** ^Multiple collating functions can be registered using the same name but
3924 ** with different eTextRep parameters and SQLite will use whichever
3925 ** function requires the least amount of data transformation.
3926 ** ^If the xCallback argument is NULL then the collating function is
3927 ** deleted. ^When all collating functions having the same name are deleted,
3928 ** that collation is no longer usable.
3929 **
3930 ** ^The collating function callback is invoked with a copy of the pArg
3931 ** application data pointer and with two strings in the encoding specified
3932 ** by the eTextRep argument. The collating function must return an
3933 ** integer that is negative, zero, or positive
3934 ** if the first string is less than, equal to, or greater than the second,
3935 ** respectively. A collating function must always return the same answer
3936 ** given the same inputs. If two or more collating functions are registered
3937 ** to the same collation name (using different eTextRep values) then all
3938 ** must give an equivalent answer when invoked with equivalent strings.
3939 ** The collating function must obey the following properties for all
3940 ** strings A, B, and C:
3941 **
3942 ** <ol>
3943 ** <li> If A==B then B==A.
3944 ** <li> If A==B and B==C then A==C.
3945 ** <li> If A<B THEN B>A.
3946 ** <li> If A<B and B<C then A<C.
3947 ** </ol>
3948 **
3949 ** If a collating function fails any of the above constraints and that
3950 ** collating function is registered and used, then the behavior of SQLite
3951 ** is undefined.
3952 **
3953 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
3954 ** with the addition that the xDestroy callback is invoked on pArg when
3955 ** the collating function is deleted.
3956 ** ^Collating functions are deleted when they are overridden by later
3957 ** calls to the collation creation functions or when the
3958 ** [database connection] is closed using [sqlite3_close()].
3959 **
3960 ** ^The xDestroy callback is <u>not</u> called if the
3961 ** sqlite3_create_collation_v2() function fails. Applications that invoke
3962 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
3963 ** check the return code and dispose of the application data pointer
3964 ** themselves rather than expecting SQLite to deal with it for them.
3965 ** This is different from every other SQLite interface. The inconsistency
3966 ** is unfortunate but cannot be changed without breaking backwards
3967 ** compatibility.
3968 **
3969 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
3970 */
3972 sqlite3*,
3977 );
3979 sqlite3*,
3985 );
3987 sqlite3*,
3992 );
3994 /*
3995 ** CAPI3REF: Collation Needed Callbacks
3996 **
3997 ** ^To avoid having to register all collation sequences before a database
3998 ** can be used, a single callback function may be registered with the
3999 ** [database connection] to be invoked whenever an undefined collation
4000 ** sequence is required.
4001 **
4002 ** ^If the function is registered using the sqlite3_collation_needed() API,
4003 ** then it is passed the names of undefined collation sequences as strings
4004 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4005 ** the names are passed as UTF-16 in machine native byte order.
4006 ** ^A call to either function replaces the existing collation-needed callback.
4007 **
4008 ** ^(When the callback is invoked, the first argument passed is a copy
4009 ** of the second argument to sqlite3_collation_needed() or
4010 ** sqlite3_collation_needed16(). The second argument is the database
4011 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4012 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4013 ** sequence function required. The fourth parameter is the name of the
4014 ** required collation sequence.)^
4015 **
4016 ** The callback function should register the desired collation using
4017 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4018 ** [sqlite3_create_collation_v2()].
4019 */
4021 sqlite3*,
4024 );
4026 sqlite3*,
4029 );
4031 #ifdef SQLITE_HAS_CODEC
4032 /*
4033 ** Specify the key for an encrypted database. This routine should be
4034 ** called right after sqlite3_open().
4035 **
4036 ** The code to implement this API is not available in the public release
4037 ** of SQLite.
4038 */
4042 );
4044 /*
4045 ** Change the key on an open database. If the current database is not
4046 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
4047 ** database is decrypted.
4048 **
4049 ** The code to implement this API is not available in the public release
4050 ** of SQLite.
4051 */
4055 );
4057 /*
4058 ** Specify the activation key for a SEE database. Unless
4059 ** activated, none of the SEE routines will work.
4060 */
4063 );
4064 #endif
4066 #ifdef SQLITE_ENABLE_CEROD
4067 /*
4068 ** Specify the activation key for a CEROD database. Unless
4069 ** activated, none of the CEROD routines will work.
4070 */
4073 );
4074 #endif
4076 /*
4077 ** CAPI3REF: Suspend Execution For A Short Time
4078 **
4079 ** The sqlite3_sleep() function causes the current thread to suspend execution
4080 ** for at least a number of milliseconds specified in its parameter.
4081 **
4082 ** If the operating system does not support sleep requests with
4083 ** millisecond time resolution, then the time will be rounded up to
4084 ** the nearest second. The number of milliseconds of sleep actually
4085 ** requested from the operating system is returned.
4086 **
4087 ** ^SQLite implements this interface by calling the xSleep()
4088 ** method of the default [sqlite3_vfs] object. If the xSleep() method
4089 ** of the default VFS is not implemented correctly, or not implemented at
4090 ** all, then the behavior of sqlite3_sleep() may deviate from the description
4091 ** in the previous paragraphs.
4092 */
4095 /*
4096 ** CAPI3REF: Name Of The Folder Holding Temporary Files
4097 **
4098 ** ^(If this global variable is made to point to a string which is
4099 ** the name of a folder (a.k.a. directory), then all temporary files
4100 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4101 ** will be placed in that directory.)^ ^If this variable
4102 ** is a NULL pointer, then SQLite performs a search for an appropriate
4103 ** temporary file directory.
4104 **
4105 ** It is not safe to read or modify this variable in more than one
4106 ** thread at a time. It is not safe to read or modify this variable
4107 ** if a [database connection] is being used at the same time in a separate
4108 ** thread.
4109 ** It is intended that this variable be set once
4110 ** as part of process initialization and before any SQLite interface
4111 ** routines have been called and that this variable remain unchanged
4112 ** thereafter.
4113 **
4114 ** ^The [temp_store_directory pragma] may modify this variable and cause
4115 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4116 ** the [temp_store_directory pragma] always assumes that any string
4117 ** that this variable points to is held in memory obtained from
4118 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4119 ** using [sqlite3_free].
4120 ** Hence, if this variable is modified directly, either it should be
4121 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4122 ** or else the use of the [temp_store_directory pragma] should be avoided.
4123 */
4126 /*
4127 ** CAPI3REF: Test For Auto-Commit Mode
4128 ** KEYWORDS: {autocommit mode}
4129 **
4130 ** ^The sqlite3_get_autocommit() interface returns non-zero or
4131 ** zero if the given database connection is or is not in autocommit mode,
4132 ** respectively. ^Autocommit mode is on by default.
4133 ** ^Autocommit mode is disabled by a [BEGIN] statement.
4134 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
4135 **
4136 ** If certain kinds of errors occur on a statement within a multi-statement
4137 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
4138 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
4139 ** transaction might be rolled back automatically. The only way to
4140 ** find out whether SQLite automatically rolled back the transaction after
4141 ** an error is to use this function.
4142 **
4143 ** If another thread changes the autocommit status of the database
4144 ** connection while this routine is running, then the return value
4145 ** is undefined.
4146 */
4149 /*
4150 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
4151 **
4152 ** ^The sqlite3_db_handle interface returns the [database connection] handle
4153 ** to which a [prepared statement] belongs. ^The [database connection]
4154 ** returned by sqlite3_db_handle is the same [database connection]
4155 ** that was the first argument
4156 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
4157 ** create the statement in the first place.
4158 */
4161 /*
4162 ** CAPI3REF: Find the next prepared statement
4163 **
4164 ** ^This interface returns a pointer to the next [prepared statement] after
4165 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
4166 ** then this interface returns a pointer to the first prepared statement
4167 ** associated with the database connection pDb. ^If no prepared statement
4168 ** satisfies the conditions of this routine, it returns NULL.
4169 **
4170 ** The [database connection] pointer D in a call to
4171 ** [sqlite3_next_stmt(D,S)] must refer to an open database
4172 ** connection and in particular must not be a NULL pointer.
4173 */
4176 /*
4177 ** CAPI3REF: Commit And Rollback Notification Callbacks
4178 **
4179 ** ^The sqlite3_commit_hook() interface registers a callback
4180 ** function to be invoked whenever a transaction is [COMMIT | committed].
4181 ** ^Any callback set by a previous call to sqlite3_commit_hook()
4182 ** for the same database connection is overridden.
4183 ** ^The sqlite3_rollback_hook() interface registers a callback
4184 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
4185 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
4186 ** for the same database connection is overridden.
4187 ** ^The pArg argument is passed through to the callback.
4188 ** ^If the callback on a commit hook function returns non-zero,
4189 ** then the commit is converted into a rollback.
4190 **
4191 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
4192 ** return the P argument from the previous call of the same function
4193 ** on the same [database connection] D, or NULL for
4194 ** the first call for each function on D.
4195 **
4196 ** The callback implementation must not do anything that will modify
4197 ** the database connection that invoked the callback. Any actions
4198 ** to modify the database connection must be deferred until after the
4199 ** completion of the [sqlite3_step()] call that triggered the commit
4200 ** or rollback hook in the first place.
4201 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
4202 ** database connections for the meaning of "modify" in this paragraph.
4203 **
4204 ** ^Registering a NULL function disables the callback.
4205 **
4206 ** ^When the commit hook callback routine returns zero, the [COMMIT]
4207 ** operation is allowed to continue normally. ^If the commit hook
4208 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
4209 ** ^The rollback hook is invoked on a rollback that results from a commit
4210 ** hook returning non-zero, just as it would be with any other rollback.
4211 **
4212 ** ^For the purposes of this API, a transaction is said to have been
4213 ** rolled back if an explicit "ROLLBACK" statement is executed, or
4214 ** an error or constraint causes an implicit rollback to occur.
4215 ** ^The rollback callback is not invoked if a transaction is
4216 ** automatically rolled back because the database connection is closed.
4217 **
4218 ** See also the [sqlite3_update_hook()] interface.
4219 */
4223 /*
4224 ** CAPI3REF: Data Change Notification Callbacks
4225 **
4226 ** ^The sqlite3_update_hook() interface registers a callback function
4227 ** with the [database connection] identified by the first argument
4228 ** to be invoked whenever a row is updated, inserted or deleted.
4229 ** ^Any callback set by a previous call to this function
4230 ** for the same database connection is overridden.
4231 **
4232 ** ^The second argument is a pointer to the function to invoke when a
4233 ** row is updated, inserted or deleted.
4234 ** ^The first argument to the callback is a copy of the third argument
4235 ** to sqlite3_update_hook().
4236 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
4237 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
4238 ** to be invoked.
4239 ** ^The third and fourth arguments to the callback contain pointers to the
4240 ** database and table name containing the affected row.
4241 ** ^The final callback parameter is the [rowid] of the row.
4242 ** ^In the case of an update, this is the [rowid] after the update takes place.
4243 **
4244 ** ^(The update hook is not invoked when internal system tables are
4245 ** modified (i.e. sqlite_master and sqlite_sequence).)^
4246 **
4247 ** ^In the current implementation, the update hook
4248 ** is not invoked when duplication rows are deleted because of an
4249 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
4250 ** invoked when rows are deleted using the [truncate optimization].
4251 ** The exceptions defined in this paragraph might change in a future
4252 ** release of SQLite.
4253 **
4254 ** The update hook implementation must not do anything that will modify
4255 ** the database connection that invoked the update hook. Any actions
4256 ** to modify the database connection must be deferred until after the
4257 ** completion of the [sqlite3_step()] call that triggered the update hook.
4258 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
4259 ** database connections for the meaning of "modify" in this paragraph.
4260 **
4261 ** ^The sqlite3_update_hook(D,C,P) function
4262 ** returns the P argument from the previous call
4263 ** on the same [database connection] D, or NULL for
4264 ** the first call on D.
4265 **
4266 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
4267 ** interfaces.
4268 */
4270 sqlite3*,
4273 );
4275 /*
4276 ** CAPI3REF: Enable Or Disable Shared Pager Cache
4277 ** KEYWORDS: {shared cache}
4278 **
4279 ** ^(This routine enables or disables the sharing of the database cache
4280 ** and schema data structures between [database connection | connections]
4281 ** to the same database. Sharing is enabled if the argument is true
4282 ** and disabled if the argument is false.)^
4283 **
4284 ** ^Cache sharing is enabled and disabled for an entire process.
4285 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
4286 ** sharing was enabled or disabled for each thread separately.
4287 **
4288 ** ^(The cache sharing mode set by this interface effects all subsequent
4289 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
4290 ** Existing database connections continue use the sharing mode
4291 ** that was in effect at the time they were opened.)^
4292 **
4293 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
4294 ** successfully. An [error code] is returned otherwise.)^
4295 **
4296 ** ^Shared cache is disabled by default. But this might change in
4297 ** future releases of SQLite. Applications that care about shared
4298 ** cache setting should set it explicitly.
4299 **
4300 ** See Also: [SQLite Shared-Cache Mode]
4301 */
4304 /*
4305 ** CAPI3REF: Attempt To Free Heap Memory
4306 **
4307 ** ^The sqlite3_release_memory() interface attempts to free N bytes
4308 ** of heap memory by deallocating non-essential memory allocations
4309 ** held by the database library. Memory used to cache database
4310 ** pages to improve performance is an example of non-essential memory.
4311 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
4312 ** which might be more or less than the amount requested.
4313 ** ^The sqlite3_release_memory() routine is a no-op returning zero
4314 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
4315 */
4318 /*
4319 ** CAPI3REF: Impose A Limit On Heap Size
4320 **
4321 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
4322 ** soft limit on the amount of heap memory that may be allocated by SQLite.
4323 ** ^SQLite strives to keep heap memory utilization below the soft heap
4324 ** limit by reducing the number of pages held in the page cache
4325 ** as heap memory usages approaches the limit.
4326 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
4327 ** below the limit, it will exceed the limit rather than generate
4328 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
4329 ** is advisory only.
4330 **
4331 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
4332 ** the soft heap limit prior to the call. ^If the argument N is negative
4333 ** then no change is made to the soft heap limit. Hence, the current
4334 ** size of the soft heap limit can be determined by invoking
4335 ** sqlite3_soft_heap_limit64() with a negative argument.
4336 **
4337 ** ^If the argument N is zero then the soft heap limit is disabled.
4338 **
4339 ** ^(The soft heap limit is not enforced in the current implementation
4340 ** if one or more of following conditions are true:
4341 **
4342 ** <ul>
4343 ** <li> The soft heap limit is set to zero.
4344 ** <li> Memory accounting is disabled using a combination of the
4345 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
4346 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
4347 ** <li> An alternative page cache implementation is specified using
4348 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE],...).
4349 ** <li> The page cache allocates from its own memory pool supplied
4350 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
4351 ** from the heap.
4352 ** </ul>)^
4353 **
4354 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
4355 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
4356 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
4357 ** the soft heap limit is enforced on every memory allocation. Without
4358 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
4359 ** when memory is allocated by the page cache. Testing suggests that because
4360 ** the page cache is the predominate memory user in SQLite, most
4361 ** applications will achieve adequate soft heap limit enforcement without
4362 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
4363 **
4364 ** The circumstances under which SQLite will enforce the soft heap limit may
4365 ** changes in future releases of SQLite.
4366 */
4369 /*
4370 ** CAPI3REF: Deprecated Soft Heap Limit Interface
4371 ** DEPRECATED
4372 **
4373 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
4374 ** interface. This routine is provided for historical compatibility
4375 ** only. All new applications should use the
4376 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
4377 */
4381 /*
4382 ** CAPI3REF: Extract Metadata About A Column Of A Table
4383 **
4384 ** ^This routine returns metadata about a specific column of a specific
4385 ** database table accessible using the [database connection] handle
4386 ** passed as the first function argument.
4387 **
4388 ** ^The column is identified by the second, third and fourth parameters to
4389 ** this function. ^The second parameter is either the name of the database
4390 ** (i.e. "main", "temp", or an attached database) containing the specified
4391 ** table or NULL. ^If it is NULL, then all attached databases are searched
4392 ** for the table using the same algorithm used by the database engine to
4393 ** resolve unqualified table references.
4394 **
4395 ** ^The third and fourth parameters to this function are the table and column
4396 ** name of the desired column, respectively. Neither of these parameters
4397 ** may be NULL.
4398 **
4399 ** ^Metadata is returned by writing to the memory locations passed as the 5th
4400 ** and subsequent parameters to this function. ^Any of these arguments may be
4401 ** NULL, in which case the corresponding element of metadata is omitted.
4402 **
4403 ** ^(<blockquote>
4404 ** <table border="1">
4405 ** <tr><th> Parameter <th> Output<br>Type <th> Description
4406 **
4407 ** <tr><td> 5th <td> const char* <td> Data type
4408 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
4409 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
4410 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
4411 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
4412 ** </table>
4413 ** </blockquote>)^
4414 **
4415 ** ^The memory pointed to by the character pointers returned for the
4416 ** declaration type and collation sequence is valid only until the next
4417 ** call to any SQLite API function.
4418 **
4419 ** ^If the specified table is actually a view, an [error code] is returned.
4420 **
4421 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an
4422 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
4423 ** parameters are set for the explicitly declared column. ^(If there is no
4424 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
4425 ** parameters are set as follows:
4426 **
4427 ** <pre>
4428 ** data type: "INTEGER"
4429 ** collation sequence: "BINARY"
4430 ** not null: 0
4431 ** primary key: 1
4432 ** auto increment: 0
4433 ** </pre>)^
4434 **
4435 ** ^(This function may load one or more schemas from database files. If an
4436 ** error occurs during this process, or if the requested table or column
4437 ** cannot be found, an [error code] is returned and an error message left
4438 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
4439 **
4440 ** ^This API is only available if the library was compiled with the
4441 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
4442 */
4453 );
4455 /*
4456 ** CAPI3REF: Load An Extension
4457 **
4458 ** ^This interface loads an SQLite extension library from the named file.
4459 **
4460 ** ^The sqlite3_load_extension() interface attempts to load an
4461 ** SQLite extension library contained in the file zFile.
4462 **
4463 ** ^The entry point is zProc.
4464 ** ^zProc may be 0, in which case the name of the entry point
4465 ** defaults to "sqlite3_extension_init".
4466 ** ^The sqlite3_load_extension() interface returns
4467 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
4468 ** ^If an error occurs and pzErrMsg is not 0, then the
4469 ** [sqlite3_load_extension()] interface shall attempt to
4470 ** fill *pzErrMsg with error message text stored in memory
4471 ** obtained from [sqlite3_malloc()]. The calling function
4472 ** should free this memory by calling [sqlite3_free()].
4473 **
4474 ** ^Extension loading must be enabled using
4475 ** [sqlite3_enable_load_extension()] prior to calling this API,
4476 ** otherwise an error will be returned.
4477 **
4478 ** See also the [load_extension() SQL function].
4479 */
4485 );
4487 /*
4488 ** CAPI3REF: Enable Or Disable Extension Loading
4489 **
4490 ** ^So as not to open security holes in older applications that are
4491 ** unprepared to deal with extension loading, and as a means of disabling
4492 ** extension loading while evaluating user-entered SQL, the following API
4493 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
4494 **
4495 ** ^Extension loading is off by default. See ticket #1863.
4496 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
4497 ** to turn extension loading on and call it with onoff==0 to turn
4498 ** it back off again.
4499 */
4502 /*
4503 ** CAPI3REF: Automatically Load Statically Linked Extensions
4504 **
4505 ** ^This interface causes the xEntryPoint() function to be invoked for
4506 ** each new [database connection] that is created. The idea here is that
4507 ** xEntryPoint() is the entry point for a statically linked SQLite extension
4508 ** that is to be automatically loaded into all new database connections.
4509 **
4510 ** ^(Even though the function prototype shows that xEntryPoint() takes
4511 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
4512 ** arguments and expects and integer result as if the signature of the
4513 ** entry point where as follows:
4514 **
4515 ** <blockquote><pre>
4516 ** int xEntryPoint(
4517 ** sqlite3 *db,
4518 ** const char **pzErrMsg,
4519 ** const struct sqlite3_api_routines *pThunk
4520 ** );
4521 ** </pre></blockquote>)^
4522 **
4523 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
4524 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
4525 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
4526 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
4527 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
4528 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
4529 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
4530 **
4531 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
4532 ** on the list of automatic extensions is a harmless no-op. ^No entry point
4533 ** will be called more than once for each database connection that is opened.
4534 **
4535 ** See also: [sqlite3_reset_auto_extension()].
4536 */
4539 /*
4540 ** CAPI3REF: Reset Automatic Extension Loading
4541 **
4542 ** ^This interface disables all automatic extensions previously
4543 ** registered using [sqlite3_auto_extension()].
4544 */
4547 /*
4548 ** The interface to the virtual-table mechanism is currently considered
4549 ** to be experimental. The interface might change in incompatible ways.
4550 ** If this is a problem for you, do not use the interface at this time.
4551 **
4552 ** When the virtual-table mechanism stabilizes, we will declare the
4553 ** interface fixed, support it indefinitely, and remove this comment.
4554 */
4556 /*
4557 ** Structures used by the virtual table interface
4558 */
4564 /*
4565 ** CAPI3REF: Virtual Table Object
4566 ** KEYWORDS: sqlite3_module {virtual table module}
4567 **
4568 ** This structure, sometimes called a "virtual table module",
4569 ** defines the implementation of a [virtual tables].
4570 ** This structure consists mostly of methods for the module.
4571 **
4572 ** ^A virtual table module is created by filling in a persistent
4573 ** instance of this structure and passing a pointer to that instance
4574 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
4575 ** ^The registration remains valid until it is replaced by a different
4576 ** module or until the [database connection] closes. The content
4577 ** of this structure must not change while it is registered with
4578 ** any database connection.
4579 */
4608 };
4610 /*
4611 ** CAPI3REF: Virtual Table Indexing Information
4612 ** KEYWORDS: sqlite3_index_info
4613 **
4614 ** The sqlite3_index_info structure and its substructures is used as part
4615 ** of the [virtual table] interface to
4616 ** pass information into and receive the reply from the [xBestIndex]
4617 ** method of a [virtual table module]. The fields under **Inputs** are the
4618 ** inputs to xBestIndex and are read-only. xBestIndex inserts its
4619 ** results into the **Outputs** fields.
4620 **
4621 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
4622 **
4623 ** <blockquote>column OP expr</blockquote>
4624 **
4625 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is
4626 ** stored in aConstraint[].op using one of the
4627 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
4628 ** ^(The index of the column is stored in
4629 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
4630 ** expr on the right-hand side can be evaluated (and thus the constraint
4631 ** is usable) and false if it cannot.)^
4632 **
4633 ** ^The optimizer automatically inverts terms of the form "expr OP column"
4634 ** and makes other simplifications to the WHERE clause in an attempt to
4635 ** get as many WHERE clause terms into the form shown above as possible.
4636 ** ^The aConstraint[] array only reports WHERE clause terms that are
4637 ** relevant to the particular virtual table being queried.
4638 **
4639 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
4640 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
4641 **
4642 ** The [xBestIndex] method must fill aConstraintUsage[] with information
4643 ** about what parameters to pass to xFilter. ^If argvIndex>0 then
4644 ** the right-hand side of the corresponding aConstraint[] is evaluated
4645 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
4646 ** is true, then the constraint is assumed to be fully handled by the
4647 ** virtual table and is not checked again by SQLite.)^
4648 **
4649 ** ^The idxNum and idxPtr values are recorded and passed into the
4650 ** [xFilter] method.
4651 ** ^[sqlite3_free()] is used to free idxPtr if and only if
4652 ** needToFreeIdxPtr is true.
4653 **
4654 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
4655 ** the correct order to satisfy the ORDER BY clause so that no separate
4656 ** sorting step is required.
4657 **
4658 ** ^The estimatedCost value is an estimate of the cost of doing the
4659 ** particular lookup. A full scan of a table with N entries should have
4660 ** a cost of N. A binary search of a table of N entries should have a
4661 ** cost of approximately log(N).
4662 */
4664 /* Inputs */
4677 /* Outputs */
4687 };
4689 /*
4690 ** CAPI3REF: Virtual Table Constraint Operator Codes
4691 **
4692 ** These macros defined the allowed values for the
4693 ** [sqlite3_index_info].aConstraint[].op field. Each value represents
4694 ** an operator that is part of a constraint term in the wHERE clause of
4695 ** a query that uses a [virtual table].
4696 */
4697 #define SQLITE_INDEX_CONSTRAINT_EQ 2
4698 #define SQLITE_INDEX_CONSTRAINT_GT 4
4699 #define SQLITE_INDEX_CONSTRAINT_LE 8
4700 #define SQLITE_INDEX_CONSTRAINT_LT 16
4701 #define SQLITE_INDEX_CONSTRAINT_GE 32
4702 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
4704 /*
4705 ** CAPI3REF: Register A Virtual Table Implementation
4706 **
4707 ** ^These routines are used to register a new [virtual table module] name.
4708 ** ^Module names must be registered before
4709 ** creating a new [virtual table] using the module and before using a
4710 ** preexisting [virtual table] for the module.
4711 **
4712 ** ^The module name is registered on the [database connection] specified
4713 ** by the first parameter. ^The name of the module is given by the
4714 ** second parameter. ^The third parameter is a pointer to
4715 ** the implementation of the [virtual table module]. ^The fourth
4716 ** parameter is an arbitrary client data pointer that is passed through
4717 ** into the [xCreate] and [xConnect] methods of the virtual table module
4718 ** when a new virtual table is be being created or reinitialized.
4719 **
4720 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
4721 ** is a pointer to a destructor for the pClientData. ^SQLite will
4722 ** invoke the destructor function (if it is not NULL) when SQLite
4723 ** no longer needs the pClientData pointer. ^The destructor will also
4724 ** be invoked if the call to sqlite3_create_module_v2() fails.
4725 ** ^The sqlite3_create_module()
4726 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
4727 ** destructor.
4728 */
4734 );
4741 );
4743 /*
4744 ** CAPI3REF: Virtual Table Instance Object
4745 ** KEYWORDS: sqlite3_vtab
4746 **
4747 ** Every [virtual table module] implementation uses a subclass
4748 ** of this object to describe a particular instance
4749 ** of the [virtual table]. Each subclass will
4750 ** be tailored to the specific needs of the module implementation.
4751 ** The purpose of this superclass is to define certain fields that are
4752 ** common to all module implementations.
4753 **
4754 ** ^Virtual tables methods can set an error message by assigning a
4755 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
4756 ** take care that any prior string is freed by a call to [sqlite3_free()]
4757 ** prior to assigning a new string to zErrMsg. ^After the error message
4758 ** is delivered up to the client application, the string will be automatically
4759 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
4760 */
4765 /* Virtual table implementations will typically add additional fields */
4766 };
4768 /*
4769 ** CAPI3REF: Virtual Table Cursor Object
4770 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
4771 **
4772 ** Every [virtual table module] implementation uses a subclass of the
4773 ** following structure to describe cursors that point into the
4774 ** [virtual table] and are used
4775 ** to loop through the virtual table. Cursors are created using the
4776 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
4777 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
4778 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
4779 ** of the module. Each module implementation will define
4780 ** the content of a cursor structure to suit its own needs.
4781 **
4782 ** This superclass exists in order to define fields of the cursor that
4783 ** are common to all implementations.
4784 */
4787 /* Virtual table implementations will typically add additional fields */
4788 };
4790 /*
4791 ** CAPI3REF: Declare The Schema Of A Virtual Table
4792 **
4793 ** ^The [xCreate] and [xConnect] methods of a
4794 ** [virtual table module] call this interface
4795 ** to declare the format (the names and datatypes of the columns) of
4796 ** the virtual tables they implement.
4797 */
4800 /*
4801 ** CAPI3REF: Overload A Function For A Virtual Table
4802 **
4803 ** ^(Virtual tables can provide alternative implementations of functions
4804 ** using the [xFindFunction] method of the [virtual table module].
4805 ** But global versions of those functions
4806 ** must exist in order to be overloaded.)^
4807 **
4808 ** ^(This API makes sure a global version of a function with a particular
4809 ** name and number of parameters exists. If no such function exists
4810 ** before this API is called, a new function is created.)^ ^The implementation
4811 ** of the new function always causes an exception to be thrown. So
4812 ** the new function is not good for anything by itself. Its only
4813 ** purpose is to be a placeholder function that can be overloaded
4814 ** by a [virtual table].
4815 */
4818 /*
4819 ** The interface to the virtual-table mechanism defined above (back up
4820 ** to a comment remarkably similar to this one) is currently considered
4821 ** to be experimental. The interface might change in incompatible ways.
4822 ** If this is a problem for you, do not use the interface at this time.
4823 **
4824 ** When the virtual-table mechanism stabilizes, we will declare the
4825 ** interface fixed, support it indefinitely, and remove this comment.
4826 */
4828 /*
4829 ** CAPI3REF: A Handle To An Open BLOB
4830 ** KEYWORDS: {BLOB handle} {BLOB handles}
4831 **
4832 ** An instance of this object represents an open BLOB on which
4833 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
4834 ** ^Objects of this type are created by [sqlite3_blob_open()]
4835 ** and destroyed by [sqlite3_blob_close()].
4836 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
4837 ** can be used to read or write small subsections of the BLOB.
4838 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
4839 */
4842 /*
4843 ** CAPI3REF: Open A BLOB For Incremental I/O
4844 **
4845 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
4846 ** in row iRow, column zColumn, table zTable in database zDb;
4847 ** in other words, the same BLOB that would be selected by:
4848 **
4849 ** <pre>
4850 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
4851 ** </pre>)^
4852 **
4853 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
4854 ** and write access. ^If it is zero, the BLOB is opened for read access.
4855 ** ^It is not possible to open a column that is part of an index or primary
4856 ** key for writing. ^If [foreign key constraints] are enabled, it is
4857 ** not possible to open a column that is part of a [child key] for writing.
4858 **
4859 ** ^Note that the database name is not the filename that contains
4860 ** the database but rather the symbolic name of the database that
4861 ** appears after the AS keyword when the database is connected using [ATTACH].
4862 ** ^For the main database file, the database name is "main".
4863 ** ^For TEMP tables, the database name is "temp".
4864 **
4865 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
4866 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
4867 ** to be a null pointer.)^
4868 ** ^This function sets the [database connection] error code and message
4869 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
4870 ** functions. ^Note that the *ppBlob variable is always initialized in a
4871 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
4872 ** regardless of the success or failure of this routine.
4873 **
4874 ** ^(If the row that a BLOB handle points to is modified by an
4875 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
4876 ** then the BLOB handle is marked as "expired".
4877 ** This is true if any column of the row is changed, even a column
4878 ** other than the one the BLOB handle is open on.)^
4879 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
4880 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
4881 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
4882 ** rolled back by the expiration of the BLOB. Such changes will eventually
4883 ** commit if the transaction continues to completion.)^
4884 **
4885 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
4886 ** the opened blob. ^The size of a blob may not be changed by this
4887 ** interface. Use the [UPDATE] SQL command to change the size of a
4888 ** blob.
4889 **
4890 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
4891 ** and the built-in [zeroblob] SQL function can be used, if desired,
4892 ** to create an empty, zero-filled blob in which to read or write using
4893 ** this interface.
4894 **
4895 ** To avoid a resource leak, every open [BLOB handle] should eventually
4896 ** be released by a call to [sqlite3_blob_close()].
4897 */
4899 sqlite3*,
4903 sqlite3_int64 iRow,
4905 sqlite3_blob **ppBlob
4906 );
4908 /*
4909 ** CAPI3REF: Move a BLOB Handle to a New Row
4910 **
4911 ** ^This function is used to move an existing blob handle so that it points
4912 ** to a different row of the same database table. ^The new row is identified
4913 ** by the rowid value passed as the second argument. Only the row can be
4914 ** changed. ^The database, table and column on which the blob handle is open
4915 ** remain the same. Moving an existing blob handle to a new row can be
4916 ** faster than closing the existing handle and opening a new one.
4917 **
4918 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
4919 ** it must exist and there must be either a blob or text value stored in
4920 ** the nominated column.)^ ^If the new row is not present in the table, or if
4921 ** it does not contain a blob or text value, or if another error occurs, an
4922 ** SQLite error code is returned and the blob handle is considered aborted.
4923 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
4924 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
4925 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
4926 ** always returns zero.
4927 **
4928 ** ^This function sets the database handle error code and message.
4929 */
4932 /*
4933 ** CAPI3REF: Close A BLOB Handle
4934 **
4935 ** ^Closes an open [BLOB handle].
4936 **
4937 ** ^Closing a BLOB shall cause the current transaction to commit
4938 ** if there are no other BLOBs, no pending prepared statements, and the
4939 ** database connection is in [autocommit mode].
4940 ** ^If any writes were made to the BLOB, they might be held in cache
4941 ** until the close operation if they will fit.
4942 **
4943 ** ^(Closing the BLOB often forces the changes
4944 ** out to disk and so if any I/O errors occur, they will likely occur
4945 ** at the time when the BLOB is closed. Any errors that occur during
4946 ** closing are reported as a non-zero return value.)^
4947 **
4948 ** ^(The BLOB is closed unconditionally. Even if this routine returns
4949 ** an error code, the BLOB is still closed.)^
4950 **
4951 ** ^Calling this routine with a null pointer (such as would be returned
4952 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
4953 */
4956 /*
4957 ** CAPI3REF: Return The Size Of An Open BLOB
4958 **
4959 ** ^Returns the size in bytes of the BLOB accessible via the
4960 ** successfully opened [BLOB handle] in its only argument. ^The
4961 ** incremental blob I/O routines can only read or overwriting existing
4962 ** blob content; they cannot change the size of a blob.
4963 **
4964 ** This routine only works on a [BLOB handle] which has been created
4965 ** by a prior successful call to [sqlite3_blob_open()] and which has not
4966 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
4967 ** to this routine results in undefined and probably undesirable behavior.
4968 */
4971 /*
4972 ** CAPI3REF: Read Data From A BLOB Incrementally
4973 **
4974 ** ^(This function is used to read data from an open [BLOB handle] into a
4975 ** caller-supplied buffer. N bytes of data are copied into buffer Z
4976 ** from the open BLOB, starting at offset iOffset.)^
4977 **
4978 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
4979 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
4980 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
4981 ** ^The size of the blob (and hence the maximum value of N+iOffset)
4982 ** can be determined using the [sqlite3_blob_bytes()] interface.
4983 **
4984 ** ^An attempt to read from an expired [BLOB handle] fails with an
4985 ** error code of [SQLITE_ABORT].
4986 **
4987 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
4988 ** Otherwise, an [error code] or an [extended error code] is returned.)^
4989 **
4990 ** This routine only works on a [BLOB handle] which has been created
4991 ** by a prior successful call to [sqlite3_blob_open()] and which has not
4992 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
4993 ** to this routine results in undefined and probably undesirable behavior.
4994 **
4995 ** See also: [sqlite3_blob_write()].
4996 */
4999 /*
5000 ** CAPI3REF: Write Data Into A BLOB Incrementally
5001 **
5002 ** ^This function is used to write data into an open [BLOB handle] from a
5003 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
5004 ** into the open BLOB, starting at offset iOffset.
5005 **
5006 ** ^If the [BLOB handle] passed as the first argument was not opened for
5007 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
5008 ** this function returns [SQLITE_READONLY].
5009 **
5010 ** ^This function may only modify the contents of the BLOB; it is
5011 ** not possible to increase the size of a BLOB using this API.
5012 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5013 ** [SQLITE_ERROR] is returned and no data is written. ^If N is
5014 ** less than zero [SQLITE_ERROR] is returned and no data is written.
5015 ** The size of the BLOB (and hence the maximum value of N+iOffset)
5016 ** can be determined using the [sqlite3_blob_bytes()] interface.
5017 **
5018 ** ^An attempt to write to an expired [BLOB handle] fails with an
5019 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
5020 ** before the [BLOB handle] expired are not rolled back by the
5021 ** expiration of the handle, though of course those changes might
5022 ** have been overwritten by the statement that expired the BLOB handle
5023 ** or by other independent statements.
5024 **
5025 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
5026 ** Otherwise, an [error code] or an [extended error code] is returned.)^
5027 **
5028 ** This routine only works on a [BLOB handle] which has been created
5029 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5030 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5031 ** to this routine results in undefined and probably undesirable behavior.
5032 **
5033 ** See also: [sqlite3_blob_read()].
5034 */
5037 /*
5038 ** CAPI3REF: Virtual File System Objects
5039 **
5040 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
5041 ** that SQLite uses to interact
5042 ** with the underlying operating system. Most SQLite builds come with a
5043 ** single default VFS that is appropriate for the host computer.
5044 ** New VFSes can be registered and existing VFSes can be unregistered.
5045 ** The following interfaces are provided.
5046 **
5047 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
5048 ** ^Names are case sensitive.
5049 ** ^Names are zero-terminated UTF-8 strings.
5050 ** ^If there is no match, a NULL pointer is returned.
5051 ** ^If zVfsName is NULL then the default VFS is returned.
5052 **
5053 ** ^New VFSes are registered with sqlite3_vfs_register().
5054 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
5055 ** ^The same VFS can be registered multiple times without injury.
5056 ** ^To make an existing VFS into the default VFS, register it again
5057 ** with the makeDflt flag set. If two different VFSes with the
5058 ** same name are registered, the behavior is undefined. If a
5059 ** VFS is registered with a name that is NULL or an empty string,
5060 ** then the behavior is undefined.
5061 **
5062 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
5063 ** ^(If the default VFS is unregistered, another VFS is chosen as
5064 ** the default. The choice for the new VFS is arbitrary.)^
5065 */
5070 /*
5071 ** CAPI3REF: Mutexes
5072 **
5073 ** The SQLite core uses these routines for thread
5074 ** synchronization. Though they are intended for internal
5075 ** use by SQLite, code that links against SQLite is
5076 ** permitted to use any of these routines.
5077 **
5078 ** The SQLite source code contains multiple implementations
5079 ** of these mutex routines. An appropriate implementation
5080 ** is selected automatically at compile-time. ^(The following
5081 ** implementations are available in the SQLite core:
5082 **
5083 ** <ul>
5084 ** <li> SQLITE_MUTEX_OS2
5085 ** <li> SQLITE_MUTEX_PTHREAD
5086 ** <li> SQLITE_MUTEX_W32
5087 ** <li> SQLITE_MUTEX_NOOP
5088 ** </ul>)^
5089 **
5090 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
5091 ** that does no real locking and is appropriate for use in
5092 ** a single-threaded application. ^The SQLITE_MUTEX_OS2,
5093 ** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
5094 ** are appropriate for use on OS/2, Unix, and Windows.
5095 **
5096 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
5097 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
5098 ** implementation is included with the library. In this case the
5099 ** application must supply a custom mutex implementation using the
5100 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
5101 ** before calling sqlite3_initialize() or any other public sqlite3_
5102 ** function that calls sqlite3_initialize().)^
5103 **
5104 ** ^The sqlite3_mutex_alloc() routine allocates a new
5105 ** mutex and returns a pointer to it. ^If it returns NULL
5106 ** that means that a mutex could not be allocated. ^SQLite
5107 ** will unwind its stack and return an error. ^(The argument
5108 ** to sqlite3_mutex_alloc() is one of these integer constants:
5109 **
5110 ** <ul>
5111 ** <li> SQLITE_MUTEX_FAST
5112 ** <li> SQLITE_MUTEX_RECURSIVE
5113 ** <li> SQLITE_MUTEX_STATIC_MASTER
5114 ** <li> SQLITE_MUTEX_STATIC_MEM
5115 ** <li> SQLITE_MUTEX_STATIC_MEM2
5116 ** <li> SQLITE_MUTEX_STATIC_PRNG
5117 ** <li> SQLITE_MUTEX_STATIC_LRU
5118 ** <li> SQLITE_MUTEX_STATIC_LRU2
5119 ** </ul>)^
5120 **
5121 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
5122 ** cause sqlite3_mutex_alloc() to create
5123 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
5124 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
5125 ** The mutex implementation does not need to make a distinction
5126 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
5127 ** not want to. ^SQLite will only request a recursive mutex in
5128 ** cases where it really needs one. ^If a faster non-recursive mutex
5129 ** implementation is available on the host platform, the mutex subsystem
5130 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
5131 **
5132 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
5133 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
5134 ** a pointer to a static preexisting mutex. ^Six static mutexes are
5135 ** used by the current version of SQLite. Future versions of SQLite
5136 ** may add additional static mutexes. Static mutexes are for internal
5137 ** use by SQLite only. Applications that use SQLite mutexes should
5138 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
5139 ** SQLITE_MUTEX_RECURSIVE.
5140 **
5141 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
5142 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
5143 ** returns a different mutex on every call. ^But for the static
5144 ** mutex types, the same mutex is returned on every call that has
5145 ** the same type number.
5146 **
5147 ** ^The sqlite3_mutex_free() routine deallocates a previously
5148 ** allocated dynamic mutex. ^SQLite is careful to deallocate every
5149 ** dynamic mutex that it allocates. The dynamic mutexes must not be in
5150 ** use when they are deallocated. Attempting to deallocate a static
5151 ** mutex results in undefined behavior. ^SQLite never deallocates
5152 ** a static mutex.
5153 **
5154 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
5155 ** to enter a mutex. ^If another thread is already within the mutex,
5156 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
5157 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
5158 ** upon successful entry. ^(Mutexes created using
5159 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
5160 ** In such cases the,
5161 ** mutex must be exited an equal number of times before another thread
5162 ** can enter.)^ ^(If the same thread tries to enter any other
5163 ** kind of mutex more than once, the behavior is undefined.
5164 ** SQLite will never exhibit
5165 ** such behavior in its own use of mutexes.)^
5166 **
5167 ** ^(Some systems (for example, Windows 95) do not support the operation
5168 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
5169 ** will always return SQLITE_BUSY. The SQLite core only ever uses
5170 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
5171 **
5172 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
5173 ** previously entered by the same thread. ^(The behavior
5174 ** is undefined if the mutex is not currently entered by the
5175 ** calling thread or is not currently allocated. SQLite will
5176 ** never do either.)^
5177 **
5178 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
5179 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
5180 ** behave as no-ops.
5181 **
5182 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
5183 */
5190 /*
5191 ** CAPI3REF: Mutex Methods Object
5192 **
5193 ** An instance of this structure defines the low-level routines
5194 ** used to allocate and use mutexes.
5195 **
5196 ** Usually, the default mutex implementations provided by SQLite are
5197 ** sufficient, however the user has the option of substituting a custom
5198 ** implementation for specialized deployments or systems for which SQLite
5199 ** does not provide a suitable implementation. In this case, the user
5200 ** creates and populates an instance of this structure to pass
5201 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
5202 ** Additionally, an instance of this structure can be used as an
5203 ** output variable when querying the system for the current mutex
5204 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
5205 **
5206 ** ^The xMutexInit method defined by this structure is invoked as
5207 ** part of system initialization by the sqlite3_initialize() function.
5208 ** ^The xMutexInit routine is called by SQLite exactly once for each
5209 ** effective call to [sqlite3_initialize()].
5210 **
5211 ** ^The xMutexEnd method defined by this structure is invoked as
5212 ** part of system shutdown by the sqlite3_shutdown() function. The
5213 ** implementation of this method is expected to release all outstanding
5214 ** resources obtained by the mutex methods implementation, especially
5215 ** those obtained by the xMutexInit method. ^The xMutexEnd()
5216 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
5217 **
5218 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
5219 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
5220 ** xMutexNotheld) implement the following interfaces (respectively):
5221 **
5222 ** <ul>
5223 ** <li> [sqlite3_mutex_alloc()] </li>
5224 ** <li> [sqlite3_mutex_free()] </li>
5225 ** <li> [sqlite3_mutex_enter()] </li>
5226 ** <li> [sqlite3_mutex_try()] </li>
5227 ** <li> [sqlite3_mutex_leave()] </li>
5228 ** <li> [sqlite3_mutex_held()] </li>
5229 ** <li> [sqlite3_mutex_notheld()] </li>
5230 ** </ul>)^
5231 **
5232 ** The only difference is that the public sqlite3_XXX functions enumerated
5233 ** above silently ignore any invocations that pass a NULL pointer instead
5234 ** of a valid mutex handle. The implementations of the methods defined
5235 ** by this structure are not required to handle this case, the results
5236 ** of passing a NULL pointer instead of a valid mutex handle are undefined
5237 ** (i.e. it is acceptable to provide an implementation that segfaults if
5238 ** it is passed a NULL pointer).
5239 **
5240 ** The xMutexInit() method must be threadsafe. ^It must be harmless to
5241 ** invoke xMutexInit() multiple times within the same process and without
5242 ** intervening calls to xMutexEnd(). Second and subsequent calls to
5243 ** xMutexInit() must be no-ops.
5244 **
5245 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
5246 ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory
5247 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
5248 ** memory allocation for a fast or recursive mutex.
5249 **
5250 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
5251 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
5252 ** If xMutexInit fails in any way, it is expected to clean up after itself
5253 ** prior to returning.
5254 */
5266 };
5268 /*
5269 ** CAPI3REF: Mutex Verification Routines
5270 **
5271 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
5272 ** are intended for use inside assert() statements. ^The SQLite core
5273 ** never uses these routines except inside an assert() and applications
5274 ** are advised to follow the lead of the core. ^The SQLite core only
5275 ** provides implementations for these routines when it is compiled
5276 ** with the SQLITE_DEBUG flag. ^External mutex implementations
5277 ** are only required to provide these routines if SQLITE_DEBUG is
5278 ** defined and if NDEBUG is not defined.
5279 **
5280 ** ^These routines should return true if the mutex in their argument
5281 ** is held or not held, respectively, by the calling thread.
5282 **
5283 ** ^The implementation is not required to provided versions of these
5284 ** routines that actually work. If the implementation does not provide working
5285 ** versions of these routines, it should at least provide stubs that always
5286 ** return true so that one does not get spurious assertion failures.
5287 **
5288 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
5289 ** the routine should return 1. This seems counter-intuitive since
5290 ** clearly the mutex cannot be held if it does not exist. But the
5291 ** the reason the mutex does not exist is because the build is not
5292 ** using mutexes. And we do not want the assert() containing the
5293 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
5294 ** the appropriate thing to do. ^The sqlite3_mutex_notheld()
5295 ** interface should also return 1 when given a NULL pointer.
5296 */
5297 #ifndef NDEBUG
5300 #endif
5302 /*
5303 ** CAPI3REF: Mutex Types
5304 **
5305 ** The [sqlite3_mutex_alloc()] interface takes a single argument
5306 ** which is one of these integer constants.
5307 **
5308 ** The set of static mutexes may change from one SQLite release to the
5309 ** next. Applications that override the built-in mutex logic must be
5310 ** prepared to accommodate additional static mutexes.
5311 */
5312 #define SQLITE_MUTEX_FAST 0
5313 #define SQLITE_MUTEX_RECURSIVE 1
5314 #define SQLITE_MUTEX_STATIC_MASTER 2
5323 /*
5324 ** CAPI3REF: Retrieve the mutex for a database connection
5325 **
5326 ** ^This interface returns a pointer the [sqlite3_mutex] object that
5327 ** serializes access to the [database connection] given in the argument
5328 ** when the [threading mode] is Serialized.
5329 ** ^If the [threading mode] is Single-thread or Multi-thread then this
5330 ** routine returns a NULL pointer.
5331 */
5334 /*
5335 ** CAPI3REF: Low-Level Control Of Database Files
5336 **
5337 ** ^The [sqlite3_file_control()] interface makes a direct call to the
5338 ** xFileControl method for the [sqlite3_io_methods] object associated
5339 ** with a particular database identified by the second argument. ^The
5340 ** name of the database is "main" for the main database or "temp" for the
5341 ** TEMP database, or the name that appears after the AS keyword for
5342 ** databases that are added using the [ATTACH] SQL command.
5343 ** ^A NULL pointer can be used in place of "main" to refer to the
5344 ** main database file.
5345 ** ^The third and fourth parameters to this routine
5346 ** are passed directly through to the second and third parameters of
5347 ** the xFileControl method. ^The return value of the xFileControl
5348 ** method becomes the return value of this routine.
5349 **
5350 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
5351 ** a pointer to the underlying [sqlite3_file] object to be written into
5352 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER
5353 ** case is a short-circuit path which does not actually invoke the
5354 ** underlying sqlite3_io_methods.xFileControl method.
5355 **
5356 ** ^If the second parameter (zDbName) does not match the name of any
5357 ** open database file, then SQLITE_ERROR is returned. ^This error
5358 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
5359 ** or [sqlite3_errmsg()]. The underlying xFileControl method might
5360 ** also return SQLITE_ERROR. There is no way to distinguish between
5361 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
5362 ** xFileControl method.
5363 **
5364 ** See also: [SQLITE_FCNTL_LOCKSTATE]
5365 */
5368 /*
5369 ** CAPI3REF: Testing Interface
5370 **
5371 ** ^The sqlite3_test_control() interface is used to read out internal
5372 ** state of SQLite and to inject faults into SQLite for testing
5373 ** purposes. ^The first parameter is an operation code that determines
5374 ** the number, meaning, and operation of all subsequent parameters.
5375 **
5376 ** This interface is not for use by applications. It exists solely
5377 ** for verifying the correct operation of the SQLite library. Depending
5378 ** on how the SQLite library is compiled, this interface might not exist.
5379 **
5380 ** The details of the operation codes, their meanings, the parameters
5381 ** they take, and what they do are all subject to change without notice.
5382 ** Unlike most of the SQLite API, this function is not guaranteed to
5383 ** operate consistently from one release to the next.
5384 */
5387 /*
5388 ** CAPI3REF: Testing Interface Operation Codes
5389 **
5390 ** These constants are the valid operation code parameters used
5391 ** as the first argument to [sqlite3_test_control()].
5392 **
5393 ** These parameters and their meanings are subject to change
5394 ** without notice. These values are for testing purposes only.
5395 ** Applications should not use any of these parameters or the
5396 ** [sqlite3_test_control()] interface.
5397 */
5398 #define SQLITE_TESTCTRL_FIRST 5
5399 #define SQLITE_TESTCTRL_PRNG_SAVE 5
5400 #define SQLITE_TESTCTRL_PRNG_RESTORE 6
5401 #define SQLITE_TESTCTRL_PRNG_RESET 7
5402 #define SQLITE_TESTCTRL_BITVEC_TEST 8
5403 #define SQLITE_TESTCTRL_FAULT_INSTALL 9
5404 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
5405 #define SQLITE_TESTCTRL_PENDING_BYTE 11
5406 #define SQLITE_TESTCTRL_ASSERT 12
5407 #define SQLITE_TESTCTRL_ALWAYS 13
5408 #define SQLITE_TESTCTRL_RESERVE 14
5409 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
5410 #define SQLITE_TESTCTRL_ISKEYWORD 16
5411 #define SQLITE_TESTCTRL_PGHDRSZ 17
5412 #define SQLITE_TESTCTRL_SCRATCHMALLOC 18
5413 #define SQLITE_TESTCTRL_LAST 18
5415 /*
5416 ** CAPI3REF: SQLite Runtime Status
5417 **
5418 ** ^This interface is used to retrieve runtime status information
5419 ** about the performance of SQLite, and optionally to reset various
5420 ** highwater marks. ^The first argument is an integer code for
5421 ** the specific parameter to measure. ^(Recognized integer codes
5422 ** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].)^
5423 ** ^The current value of the parameter is returned into *pCurrent.
5424 ** ^The highest recorded value is returned in *pHighwater. ^If the
5425 ** resetFlag is true, then the highest record value is reset after
5426 ** *pHighwater is written. ^(Some parameters do not record the highest
5427 ** value. For those parameters
5428 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
5429 ** ^(Other parameters record only the highwater mark and not the current
5430 ** value. For these latter parameters nothing is written into *pCurrent.)^
5431 **
5432 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a
5433 ** non-zero [error code] on failure.
5434 **
5435 ** This routine is threadsafe but is not atomic. This routine can be
5436 ** called while other threads are running the same or different SQLite
5437 ** interfaces. However the values returned in *pCurrent and
5438 ** *pHighwater reflect the status of SQLite at different points in time
5439 ** and it is possible that another thread might change the parameter
5440 ** in between the times when *pCurrent and *pHighwater are written.
5441 **
5442 ** See also: [sqlite3_db_status()]
5443 */
5447 /*
5448 ** CAPI3REF: Status Parameters
5449 **
5450 ** These integer constants designate various run-time status parameters
5451 ** that can be returned by [sqlite3_status()].
5452 **
5453 ** <dl>
5454 ** ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
5455 ** <dd>This parameter is the current amount of memory checked out
5456 ** using [sqlite3_malloc()], either directly or indirectly. The
5457 ** figure includes calls made to [sqlite3_malloc()] by the application
5458 ** and internal memory usage by the SQLite library. Scratch memory
5459 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
5460 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
5461 ** this parameter. The amount returned is the sum of the allocation
5462 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
5463 **
5464 ** ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
5465 ** <dd>This parameter records the largest memory allocation request
5466 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
5467 ** internal equivalents). Only the value returned in the
5468 ** *pHighwater parameter to [sqlite3_status()] is of interest.
5469 ** The value written into the *pCurrent parameter is undefined.</dd>)^
5470 **
5471 ** ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
5472 ** <dd>This parameter records the number of separate memory allocations
5473 ** currently checked out.</dd>)^
5474 **
5475 ** ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
5476 ** <dd>This parameter returns the number of pages used out of the
5477 ** [pagecache memory allocator] that was configured using
5478 ** [SQLITE_CONFIG_PAGECACHE]. The
5479 ** value returned is in pages, not in bytes.</dd>)^
5480 **
5481 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
5482 ** <dd>This parameter returns the number of bytes of page cache
5483 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
5484 ** buffer and where forced to overflow to [sqlite3_malloc()]. The
5485 ** returned value includes allocations that overflowed because they
5486 ** where too large (they were larger than the "sz" parameter to
5487 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
5488 ** no space was left in the page cache.</dd>)^
5489 **
5490 ** ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
5491 ** <dd>This parameter records the largest memory allocation request
5492 ** handed to [pagecache memory allocator]. Only the value returned in the
5493 ** *pHighwater parameter to [sqlite3_status()] is of interest.
5494 ** The value written into the *pCurrent parameter is undefined.</dd>)^
5495 **
5496 ** ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
5497 ** <dd>This parameter returns the number of allocations used out of the
5498 ** [scratch memory allocator] configured using
5499 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not
5500 ** in bytes. Since a single thread may only have one scratch allocation
5501 ** outstanding at time, this parameter also reports the number of threads
5502 ** using scratch memory at the same time.</dd>)^
5503 **
5504 ** ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
5505 ** <dd>This parameter returns the number of bytes of scratch memory
5506 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
5507 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values
5508 ** returned include overflows because the requested allocation was too
5509 ** larger (that is, because the requested allocation was larger than the
5510 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
5511 ** slots were available.
5512 ** </dd>)^
5513 **
5514 ** ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
5515 ** <dd>This parameter records the largest memory allocation request
5516 ** handed to [scratch memory allocator]. Only the value returned in the
5517 ** *pHighwater parameter to [sqlite3_status()] is of interest.
5518 ** The value written into the *pCurrent parameter is undefined.</dd>)^
5519 **
5520 ** ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
5521 ** <dd>This parameter records the deepest parser stack. It is only
5522 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
5523 ** </dl>
5524 **
5525 ** New status parameters may be added from time to time.
5526 */
5527 #define SQLITE_STATUS_MEMORY_USED 0
5528 #define SQLITE_STATUS_PAGECACHE_USED 1
5529 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
5530 #define SQLITE_STATUS_SCRATCH_USED 3
5531 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4
5532 #define SQLITE_STATUS_MALLOC_SIZE 5
5533 #define SQLITE_STATUS_PARSER_STACK 6
5534 #define SQLITE_STATUS_PAGECACHE_SIZE 7
5535 #define SQLITE_STATUS_SCRATCH_SIZE 8
5536 #define SQLITE_STATUS_MALLOC_COUNT 9
5538 /*
5539 ** CAPI3REF: Database Connection Status
5540 **
5541 ** ^This interface is used to retrieve runtime status information
5542 ** about a single [database connection]. ^The first argument is the
5543 ** database connection object to be interrogated. ^The second argument
5544 ** is an integer constant, taken from the set of
5545 ** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros, that
5546 ** determines the parameter to interrogate. The set of
5547 ** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros is likely
5548 ** to grow in future releases of SQLite.
5549 **
5550 ** ^The current value of the requested parameter is written into *pCur
5551 ** and the highest instantaneous value is written into *pHiwtr. ^If
5552 ** the resetFlg is true, then the highest instantaneous value is
5553 ** reset back down to the current value.
5554 **
5555 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
5556 ** non-zero [error code] on failure.
5557 **
5558 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
5559 */
5562 /*
5563 ** CAPI3REF: Status Parameters for database connections
5564 **
5565 ** These constants are the available integer "verbs" that can be passed as
5566 ** the second argument to the [sqlite3_db_status()] interface.
5567 **
5568 ** New verbs may be added in future releases of SQLite. Existing verbs
5569 ** might be discontinued. Applications should check the return code from
5570 ** [sqlite3_db_status()] to make sure that the call worked.
5571 ** The [sqlite3_db_status()] interface will return a non-zero error code
5572 ** if a discontinued or unsupported verb is invoked.
5573 **
5574 ** <dl>
5575 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
5576 ** <dd>This parameter returns the number of lookaside memory slots currently
5577 ** checked out.</dd>)^
5578 **
5579 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
5580 ** <dd>This parameter returns the number malloc attempts that were
5581 ** satisfied using lookaside memory. Only the high-water value is meaningful;
5582 ** the current value is always zero.)^
5583 **
5584 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
5585 ** <dd>This parameter returns the number malloc attempts that might have
5586 ** been satisfied using lookaside memory but failed due to the amount of
5587 ** memory requested being larger than the lookaside slot size.
5588 ** Only the high-water value is meaningful;
5589 ** the current value is always zero.)^
5590 **
5591 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
5592 ** <dd>This parameter returns the number malloc attempts that might have
5593 ** been satisfied using lookaside memory but failed due to all lookaside
5594 ** memory already being in use.
5595 ** Only the high-water value is meaningful;
5596 ** the current value is always zero.)^
5597 **
5598 ** ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
5599 ** <dd>This parameter returns the approximate number of of bytes of heap
5600 ** memory used by all pager caches associated with the database connection.)^
5601 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
5602 **
5603 ** ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
5604 ** <dd>This parameter returns the approximate number of of bytes of heap
5605 ** memory used to store the schema for all databases associated
5606 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
5607 ** ^The full amount of memory used by the schemas is reported, even if the
5608 ** schema memory is shared with other database connections due to
5609 ** [shared cache mode] being enabled.
5610 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
5611 **
5612 ** ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
5613 ** <dd>This parameter returns the approximate number of of bytes of heap
5614 ** and lookaside memory used by all prepared statements associated with
5615 ** the database connection.)^
5616 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
5617 ** </dd>
5618 ** </dl>
5619 */
5620 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
5621 #define SQLITE_DBSTATUS_CACHE_USED 1
5622 #define SQLITE_DBSTATUS_SCHEMA_USED 2
5623 #define SQLITE_DBSTATUS_STMT_USED 3
5624 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
5625 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
5626 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
5630 /*
5631 ** CAPI3REF: Prepared Statement Status
5632 **
5633 ** ^(Each prepared statement maintains various
5634 ** [SQLITE_STMTSTATUS_SORT | counters] that measure the number
5635 ** of times it has performed specific operations.)^ These counters can
5636 ** be used to monitor the performance characteristics of the prepared
5637 ** statements. For example, if the number of table steps greatly exceeds
5638 ** the number of table searches or result rows, that would tend to indicate
5639 ** that the prepared statement is using a full table scan rather than
5640 ** an index.
5641 **
5642 ** ^(This interface is used to retrieve and reset counter values from
5643 ** a [prepared statement]. The first argument is the prepared statement
5644 ** object to be interrogated. The second argument
5645 ** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter]
5646 ** to be interrogated.)^
5647 ** ^The current value of the requested counter is returned.
5648 ** ^If the resetFlg is true, then the counter is reset to zero after this
5649 ** interface call returns.
5650 **
5651 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
5652 */
5655 /*
5656 ** CAPI3REF: Status Parameters for prepared statements
5657 **
5658 ** These preprocessor macros define integer codes that name counter
5659 ** values associated with the [sqlite3_stmt_status()] interface.
5660 ** The meanings of the various counters are as follows:
5661 **
5662 ** <dl>
5663 ** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
5664 ** <dd>^This is the number of times that SQLite has stepped forward in
5665 ** a table as part of a full table scan. Large numbers for this counter
5666 ** may indicate opportunities for performance improvement through
5667 ** careful use of indices.</dd>
5668 **
5669 ** <dt>SQLITE_STMTSTATUS_SORT</dt>
5670 ** <dd>^This is the number of sort operations that have occurred.
5671 ** A non-zero value in this counter may indicate an opportunity to
5672 ** improvement performance through careful use of indices.</dd>
5673 **
5674 ** <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
5675 ** <dd>^This is the number of rows inserted into transient indices that
5676 ** were created automatically in order to help joins run faster.
5677 ** A non-zero value in this counter may indicate an opportunity to
5678 ** improvement performance by adding permanent indices that do not
5679 ** need to be reinitialized each time the statement is run.</dd>
5680 **
5681 ** </dl>
5682 */
5683 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
5684 #define SQLITE_STMTSTATUS_SORT 2
5685 #define SQLITE_STMTSTATUS_AUTOINDEX 3
5687 /*
5688 ** CAPI3REF: Custom Page Cache Object
5689 **
5690 ** The sqlite3_pcache type is opaque. It is implemented by
5691 ** the pluggable module. The SQLite core has no knowledge of
5692 ** its size or internal structure and never deals with the
5693 ** sqlite3_pcache object except by holding and passing pointers
5694 ** to the object.
5695 **
5696 ** See [sqlite3_pcache_methods] for additional information.
5697 */
5700 /*
5701 ** CAPI3REF: Application Defined Page Cache.
5702 ** KEYWORDS: {page cache}
5703 **
5704 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can
5705 ** register an alternative page cache implementation by passing in an
5706 ** instance of the sqlite3_pcache_methods structure.)^
5707 ** In many applications, most of the heap memory allocated by
5708 ** SQLite is used for the page cache.
5709 ** By implementing a
5710 ** custom page cache using this API, an application can better control
5711 ** the amount of memory consumed by SQLite, the way in which
5712 ** that memory is allocated and released, and the policies used to
5713 ** determine exactly which parts of a database file are cached and for
5714 ** how long.
5715 **
5716 ** The alternative page cache mechanism is an
5717 ** extreme measure that is only needed by the most demanding applications.
5718 ** The built-in page cache is recommended for most uses.
5719 **
5720 ** ^(The contents of the sqlite3_pcache_methods structure are copied to an
5721 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
5722 ** the application may discard the parameter after the call to
5723 ** [sqlite3_config()] returns.)^
5724 **
5725 ** ^(The xInit() method is called once for each effective
5726 ** call to [sqlite3_initialize()])^
5727 ** (usually only once during the lifetime of the process). ^(The xInit()
5728 ** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^
5729 ** The intent of the xInit() method is to set up global data structures
5730 ** required by the custom page cache implementation.
5731 ** ^(If the xInit() method is NULL, then the
5732 ** built-in default page cache is used instead of the application defined
5733 ** page cache.)^
5734 **
5735 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
5736 ** It can be used to clean up
5737 ** any outstanding resources before process shutdown, if required.
5738 ** ^The xShutdown() method may be NULL.
5739 **
5740 ** ^SQLite automatically serializes calls to the xInit method,
5741 ** so the xInit method need not be threadsafe. ^The
5742 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
5743 ** not need to be threadsafe either. All other methods must be threadsafe
5744 ** in multithreaded applications.
5745 **
5746 ** ^SQLite will never invoke xInit() more than once without an intervening
5747 ** call to xShutdown().
5748 **
5749 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
5750 ** SQLite will typically create one cache instance for each open database file,
5751 ** though this is not guaranteed. ^The
5752 ** first parameter, szPage, is the size in bytes of the pages that must
5753 ** be allocated by the cache. ^szPage will not be a power of two. ^szPage
5754 ** will the page size of the database file that is to be cached plus an
5755 ** increment (here called "R") of less than 250. SQLite will use the
5756 ** extra R bytes on each page to store metadata about the underlying
5757 ** database page on disk. The value of R depends
5758 ** on the SQLite version, the target platform, and how SQLite was compiled.
5759 ** ^(R is constant for a particular build of SQLite. Except, there are two
5760 ** distinct values of R when SQLite is compiled with the proprietary
5761 ** ZIPVFS extension.)^ ^The second argument to
5762 ** xCreate(), bPurgeable, is true if the cache being created will
5763 ** be used to cache database pages of a file stored on disk, or
5764 ** false if it is used for an in-memory database. The cache implementation
5765 ** does not have to do anything special based with the value of bPurgeable;
5766 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
5767 ** never invoke xUnpin() except to deliberately delete a page.
5768 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
5769 ** false will always have the "discard" flag set to true.
5770 ** ^Hence, a cache created with bPurgeable false will
5771 ** never contain any unpinned pages.
5772 **
5773 ** ^(The xCachesize() method may be called at any time by SQLite to set the
5774 ** suggested maximum cache-size (number of pages stored by) the cache
5775 ** instance passed as the first argument. This is the value configured using
5776 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
5777 ** parameter, the implementation is not required to do anything with this
5778 ** value; it is advisory only.
5779 **
5780 ** The xPagecount() method must return the number of pages currently
5781 ** stored in the cache, both pinned and unpinned.
5782 **
5783 ** The xFetch() method locates a page in the cache and returns a pointer to
5784 ** the page, or a NULL pointer.
5785 ** A "page", in this context, means a buffer of szPage bytes aligned at an
5786 ** 8-byte boundary. The page to be fetched is determined by the key. ^The
5787 ** mimimum key value is 1. After it has been retrieved using xFetch, the page
5788 ** is considered to be "pinned".
5789 **
5790 ** If the requested page is already in the page cache, then the page cache
5791 ** implementation must return a pointer to the page buffer with its content
5792 ** intact. If the requested page is not already in the cache, then the
5793 ** cache implementation should use the value of the createFlag
5794 ** parameter to help it determined what action to take:
5795 **
5796 ** <table border=1 width=85% align=center>
5797 ** <tr><th> createFlag <th> Behaviour when page is not already in cache
5798 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
5799 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
5800 ** Otherwise return NULL.
5801 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
5802 ** NULL if allocating a new page is effectively impossible.
5803 ** </table>
5804 **
5805 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
5806 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
5807 ** failed.)^ In between the to xFetch() calls, SQLite may
5808 ** attempt to unpin one or more cache pages by spilling the content of
5809 ** pinned pages to disk and synching the operating system disk cache.
5810 **
5811 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
5812 ** as its second argument. If the third parameter, discard, is non-zero,
5813 ** then the page must be evicted from the cache.
5814 ** ^If the discard parameter is
5815 ** zero, then the page may be discarded or retained at the discretion of
5816 ** page cache implementation. ^The page cache implementation
5817 ** may choose to evict unpinned pages at any time.
5818 **
5819 ** The cache must not perform any reference counting. A single
5820 ** call to xUnpin() unpins the page regardless of the number of prior calls
5821 ** to xFetch().
5822 **
5823 ** The xRekey() method is used to change the key value associated with the
5824 ** page passed as the second argument. If the cache
5825 ** previously contains an entry associated with newKey, it must be
5826 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
5827 ** to be pinned.
5828 **
5829 ** When SQLite calls the xTruncate() method, the cache must discard all
5830 ** existing cache entries with page numbers (keys) greater than or equal
5831 ** to the value of the iLimit parameter passed to xTruncate(). If any
5832 ** of these pages are pinned, they are implicitly unpinned, meaning that
5833 ** they can be safely discarded.
5834 **
5835 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
5836 ** All resources associated with the specified cache should be freed. ^After
5837 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
5838 ** handle invalid, and will not use it with any other sqlite3_pcache_methods
5839 ** functions.
5840 */
5854 };
5856 /*
5857 ** CAPI3REF: Online Backup Object
5858 **
5859 ** The sqlite3_backup object records state information about an ongoing
5860 ** online backup operation. ^The sqlite3_backup object is created by
5861 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
5862 ** [sqlite3_backup_finish()].
5863 **
5864 ** See Also: [Using the SQLite Online Backup API]
5865 */
5868 /*
5869 ** CAPI3REF: Online Backup API.
5870 **
5871 ** The backup API copies the content of one database into another.
5872 ** It is useful either for creating backups of databases or
5873 ** for copying in-memory databases to or from persistent files.
5874 **
5875 ** See Also: [Using the SQLite Online Backup API]
5876 **
5877 ** ^SQLite holds a write transaction open on the destination database file
5878 ** for the duration of the backup operation.
5879 ** ^The source database is read-locked only while it is being read;
5880 ** it is not locked continuously for the entire backup operation.
5881 ** ^Thus, the backup may be performed on a live source database without
5882 ** preventing other database connections from
5883 ** reading or writing to the source database while the backup is underway.
5884 **
5885 ** ^(To perform a backup operation:
5886 ** <ol>
5887 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
5888 ** backup,
5889 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
5890 ** the data between the two databases, and finally
5891 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
5892 ** associated with the backup operation.
5893 ** </ol>)^
5894 ** There should be exactly one call to sqlite3_backup_finish() for each
5895 ** successful call to sqlite3_backup_init().
5896 **
5897 ** <b>sqlite3_backup_init()</b>
5898 **
5899 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
5900 ** [database connection] associated with the destination database
5901 ** and the database name, respectively.
5902 ** ^The database name is "main" for the main database, "temp" for the
5903 ** temporary database, or the name specified after the AS keyword in
5904 ** an [ATTACH] statement for an attached database.
5905 ** ^The S and M arguments passed to
5906 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
5907 ** and database name of the source database, respectively.
5908 ** ^The source and destination [database connections] (parameters S and D)
5909 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
5910 ** an error.
5911 **
5912 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
5913 ** returned and an error code and error message are stored in the
5914 ** destination [database connection] D.
5915 ** ^The error code and message for the failed call to sqlite3_backup_init()
5916 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
5917 ** [sqlite3_errmsg16()] functions.
5918 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
5919 ** [sqlite3_backup] object.
5920 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
5921 ** sqlite3_backup_finish() functions to perform the specified backup
5922 ** operation.
5923 **
5924 ** <b>sqlite3_backup_step()</b>
5925 **
5926 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
5927 ** the source and destination databases specified by [sqlite3_backup] object B.
5928 ** ^If N is negative, all remaining source pages are copied.
5929 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
5930 ** are still more pages to be copied, then the function returns [SQLITE_OK].
5931 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
5932 ** from source to destination, then it returns [SQLITE_DONE].
5933 ** ^If an error occurs while running sqlite3_backup_step(B,N),
5934 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
5935 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
5936 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
5937 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
5938 **
5939 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
5940 ** <ol>
5941 ** <li> the destination database was opened read-only, or
5942 ** <li> the destination database is using write-ahead-log journaling
5943 ** and the destination and source page sizes differ, or
5944 ** <li> the destination database is an in-memory database and the
5945 ** destination and source page sizes differ.
5946 ** </ol>)^
5947 **
5948 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
5949 ** the [sqlite3_busy_handler | busy-handler function]
5950 ** is invoked (if one is specified). ^If the
5951 ** busy-handler returns non-zero before the lock is available, then
5952 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
5953 ** sqlite3_backup_step() can be retried later. ^If the source
5954 ** [database connection]
5955 ** is being used to write to the source database when sqlite3_backup_step()
5956 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
5957 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
5958 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
5959 ** [SQLITE_READONLY] is returned, then
5960 ** there is no point in retrying the call to sqlite3_backup_step(). These
5961 ** errors are considered fatal.)^ The application must accept
5962 ** that the backup operation has failed and pass the backup operation handle
5963 ** to the sqlite3_backup_finish() to release associated resources.
5964 **
5965 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
5966 ** on the destination file. ^The exclusive lock is not released until either
5967 ** sqlite3_backup_finish() is called or the backup operation is complete
5968 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
5969 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
5970 ** lasts for the duration of the sqlite3_backup_step() call.
5971 ** ^Because the source database is not locked between calls to
5972 ** sqlite3_backup_step(), the source database may be modified mid-way
5973 ** through the backup process. ^If the source database is modified by an
5974 ** external process or via a database connection other than the one being
5975 ** used by the backup operation, then the backup will be automatically
5976 ** restarted by the next call to sqlite3_backup_step(). ^If the source
5977 ** database is modified by the using the same database connection as is used
5978 ** by the backup operation, then the backup database is automatically
5979 ** updated at the same time.
5980 **
5981 ** <b>sqlite3_backup_finish()</b>
5982 **
5983 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
5984 ** application wishes to abandon the backup operation, the application
5985 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
5986 ** ^The sqlite3_backup_finish() interfaces releases all
5987 ** resources associated with the [sqlite3_backup] object.
5988 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
5989 ** active write-transaction on the destination database is rolled back.
5990 ** The [sqlite3_backup] object is invalid
5991 ** and may not be used following a call to sqlite3_backup_finish().
5992 **
5993 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
5994 ** sqlite3_backup_step() errors occurred, regardless or whether or not
5995 ** sqlite3_backup_step() completed.
5996 ** ^If an out-of-memory condition or IO error occurred during any prior
5997 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
5998 ** sqlite3_backup_finish() returns the corresponding [error code].
5999 **
6000 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
6001 ** is not a permanent error and does not affect the return value of
6002 ** sqlite3_backup_finish().
6003 **
6004 ** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b>
6005 **
6006 ** ^Each call to sqlite3_backup_step() sets two values inside
6007 ** the [sqlite3_backup] object: the number of pages still to be backed
6008 ** up and the total number of pages in the source database file.
6009 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
6010 ** retrieve these two values, respectively.
6011 **
6012 ** ^The values returned by these functions are only updated by
6013 ** sqlite3_backup_step(). ^If the source database is modified during a backup
6014 ** operation, then the values are not updated to account for any extra
6015 ** pages that need to be updated or the size of the source database file
6016 ** changing.
6017 **
6018 ** <b>Concurrent Usage of Database Handles</b>
6019 **
6020 ** ^The source [database connection] may be used by the application for other
6021 ** purposes while a backup operation is underway or being initialized.
6022 ** ^If SQLite is compiled and configured to support threadsafe database
6023 ** connections, then the source database connection may be used concurrently
6024 ** from within other threads.
6025 **
6026 ** However, the application must guarantee that the destination
6027 ** [database connection] is not passed to any other API (by any thread) after
6028 ** sqlite3_backup_init() is called and before the corresponding call to
6029 ** sqlite3_backup_finish(). SQLite does not currently check to see
6030 ** if the application incorrectly accesses the destination [database connection]
6031 ** and so no error code is reported, but the operations may malfunction
6032 ** nevertheless. Use of the destination database connection while a
6033 ** backup is in progress might also also cause a mutex deadlock.
6034 **
6035 ** If running in [shared cache mode], the application must
6036 ** guarantee that the shared cache used by the destination database
6037 ** is not accessed while the backup is running. In practice this means
6038 ** that the application must guarantee that the disk file being
6039 ** backed up to is not accessed by any connection within the process,
6040 ** not just the specific connection that was passed to sqlite3_backup_init().
6041 **
6042 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
6043 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
6044 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
6045 ** APIs are not strictly speaking threadsafe. If they are invoked at the
6046 ** same time as another thread is invoking sqlite3_backup_step() it is
6047 ** possible that they return invalid values.
6048 */
6054 );
6060 /*
6061 ** CAPI3REF: Unlock Notification
6062 **
6063 ** ^When running in shared-cache mode, a database operation may fail with
6064 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
6065 ** individual tables within the shared-cache cannot be obtained. See
6066 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
6067 ** ^This API may be used to register a callback that SQLite will invoke
6068 ** when the connection currently holding the required lock relinquishes it.
6069 ** ^This API is only available if the library was compiled with the
6070 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
6071 **
6072 ** See Also: [Using the SQLite Unlock Notification Feature].
6073 **
6074 ** ^Shared-cache locks are released when a database connection concludes
6075 ** its current transaction, either by committing it or rolling it back.
6076 **
6077 ** ^When a connection (known as the blocked connection) fails to obtain a
6078 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
6079 ** identity of the database connection (the blocking connection) that
6080 ** has locked the required resource is stored internally. ^After an
6081 ** application receives an SQLITE_LOCKED error, it may call the
6082 ** sqlite3_unlock_notify() method with the blocked connection handle as
6083 ** the first argument to register for a callback that will be invoked
6084 ** when the blocking connections current transaction is concluded. ^The
6085 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
6086 ** call that concludes the blocking connections transaction.
6087 **
6088 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
6089 ** there is a chance that the blocking connection will have already
6090 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
6091 ** If this happens, then the specified callback is invoked immediately,
6092 ** from within the call to sqlite3_unlock_notify().)^
6093 **
6094 ** ^If the blocked connection is attempting to obtain a write-lock on a
6095 ** shared-cache table, and more than one other connection currently holds
6096 ** a read-lock on the same table, then SQLite arbitrarily selects one of
6097 ** the other connections to use as the blocking connection.
6098 **
6099 ** ^(There may be at most one unlock-notify callback registered by a
6100 ** blocked connection. If sqlite3_unlock_notify() is called when the
6101 ** blocked connection already has a registered unlock-notify callback,
6102 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
6103 ** called with a NULL pointer as its second argument, then any existing
6104 ** unlock-notify callback is canceled. ^The blocked connections
6105 ** unlock-notify callback may also be canceled by closing the blocked
6106 ** connection using [sqlite3_close()].
6107 **
6108 ** The unlock-notify callback is not reentrant. If an application invokes
6109 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
6110 ** crash or deadlock may be the result.
6111 **
6112 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
6113 ** returns SQLITE_OK.
6114 **
6115 ** <b>Callback Invocation Details</b>
6116 **
6117 ** When an unlock-notify callback is registered, the application provides a
6118 ** single void* pointer that is passed to the callback when it is invoked.
6119 ** However, the signature of the callback function allows SQLite to pass
6120 ** it an array of void* context pointers. The first argument passed to
6121 ** an unlock-notify callback is a pointer to an array of void* pointers,
6122 ** and the second is the number of entries in the array.
6123 **
6124 ** When a blocking connections transaction is concluded, there may be
6125 ** more than one blocked connection that has registered for an unlock-notify
6126 ** callback. ^If two or more such blocked connections have specified the
6127 ** same callback function, then instead of invoking the callback function
6128 ** multiple times, it is invoked once with the set of void* context pointers
6129 ** specified by the blocked connections bundled together into an array.
6130 ** This gives the application an opportunity to prioritize any actions
6131 ** related to the set of unblocked database connections.
6132 **
6133 ** <b>Deadlock Detection</b>
6134 **
6135 ** Assuming that after registering for an unlock-notify callback a
6136 ** database waits for the callback to be issued before taking any further
6137 ** action (a reasonable assumption), then using this API may cause the
6138 ** application to deadlock. For example, if connection X is waiting for
6139 ** connection Y's transaction to be concluded, and similarly connection
6140 ** Y is waiting on connection X's transaction, then neither connection
6141 ** will proceed and the system may remain deadlocked indefinitely.
6142 **
6143 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
6144 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
6145 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
6146 ** unlock-notify callback is registered. The system is said to be in
6147 ** a deadlocked state if connection A has registered for an unlock-notify
6148 ** callback on the conclusion of connection B's transaction, and connection
6149 ** B has itself registered for an unlock-notify callback when connection
6150 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
6151 ** the system is also considered to be deadlocked if connection B has
6152 ** registered for an unlock-notify callback on the conclusion of connection
6153 ** C's transaction, where connection C is waiting on connection A. ^Any
6154 ** number of levels of indirection are allowed.
6155 **
6156 ** <b>The "DROP TABLE" Exception</b>
6157 **
6158 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
6159 ** always appropriate to call sqlite3_unlock_notify(). There is however,
6160 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
6161 ** SQLite checks if there are any currently executing SELECT statements
6162 ** that belong to the same connection. If there are, SQLITE_LOCKED is
6163 ** returned. In this case there is no "blocking connection", so invoking
6164 ** sqlite3_unlock_notify() results in the unlock-notify callback being
6165 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
6166 ** or "DROP INDEX" query, an infinite loop might be the result.
6167 **
6168 ** One way around this problem is to check the extended error code returned
6169 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
6170 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
6171 ** the special "DROP TABLE/INDEX" case, the extended error code is just
6172 ** SQLITE_LOCKED.)^
6173 */
6178 );
6181 /*
6182 ** CAPI3REF: String Comparison
6183 **
6184 ** ^The [sqlite3_strnicmp()] API allows applications and extensions to
6185 ** compare the contents of two buffers containing UTF-8 strings in a
6186 ** case-independent fashion, using the same definition of case independence
6187 ** that SQLite uses internally when comparing identifiers.
6188 */
6191 /*
6192 ** CAPI3REF: Error Logging Interface
6193 **
6194 ** ^The [sqlite3_log()] interface writes a message into the error log
6195 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
6196 ** ^If logging is enabled, the zFormat string and subsequent arguments are
6197 ** used with [sqlite3_snprintf()] to generate the final output string.
6198 **
6199 ** The sqlite3_log() interface is intended for use by extensions such as
6200 ** virtual tables, collating functions, and SQL functions. While there is
6201 ** nothing to prevent an application from calling sqlite3_log(), doing so
6202 ** is considered bad form.
6203 **
6204 ** The zFormat string must not be NULL.
6205 **
6206 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
6207 ** will not use dynamically allocated memory. The log message is stored in
6208 ** a fixed-length buffer on the stack. If the log message is longer than
6209 ** a few hundred characters, it will be truncated to the length of the
6210 ** buffer.
6211 */
6214 /*
6215 ** CAPI3REF: Write-Ahead Log Commit Hook
6216 **
6217 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
6218 ** will be invoked each time a database connection commits data to a
6219 ** [write-ahead log] (i.e. whenever a transaction is committed in
6220 ** [journal_mode | journal_mode=WAL mode]).
6221 **
6222 ** ^The callback is invoked by SQLite after the commit has taken place and
6223 ** the associated write-lock on the database released, so the implementation
6224 ** may read, write or [checkpoint] the database as required.
6225 **
6226 ** ^The first parameter passed to the callback function when it is invoked
6227 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
6228 ** registering the callback. ^The second is a copy of the database handle.
6229 ** ^The third parameter is the name of the database that was written to -
6230 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
6231 ** is the number of pages currently in the write-ahead log file,
6232 ** including those that were just committed.
6233 **
6234 ** The callback function should normally return [SQLITE_OK]. ^If an error
6235 ** code is returned, that error will propagate back up through the
6236 ** SQLite code base to cause the statement that provoked the callback
6237 ** to report an error, though the commit will have still occurred. If the
6238 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
6239 ** that does not correspond to any valid SQLite error code, the results
6240 ** are undefined.
6241 **
6242 ** A single database handle may have at most a single write-ahead log callback
6243 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
6244 ** previously registered write-ahead log callback. ^Note that the
6245 ** [sqlite3_wal_autocheckpoint()] interface and the
6246 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
6247 ** those overwrite any prior [sqlite3_wal_hook()] settings.
6248 */
6250 sqlite3*,
6253 );
6255 /*
6256 ** CAPI3REF: Configure an auto-checkpoint
6257 **
6258 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
6259 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
6260 ** to automatically [checkpoint]
6261 ** after committing a transaction if there are N or
6262 ** more frames in the [write-ahead log] file. ^Passing zero or
6263 ** a negative value as the nFrame parameter disables automatic
6264 ** checkpoints entirely.
6265 **
6266 ** ^The callback registered by this function replaces any existing callback
6267 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
6268 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
6269 ** configured by this function.
6270 **
6271 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
6272 ** from SQL.
6273 **
6274 ** ^Every new [database connection] defaults to having the auto-checkpoint
6275 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
6276 ** pages. The use of this interface
6277 ** is only necessary if the default setting is found to be suboptimal
6278 ** for a particular application.
6279 */
6282 /*
6283 ** CAPI3REF: Checkpoint a database
6284 **
6285 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
6286 ** on [database connection] D to be [checkpointed]. ^If X is NULL or an
6287 ** empty string, then a checkpoint is run on all databases of
6288 ** connection D. ^If the database connection D is not in
6289 ** [WAL | write-ahead log mode] then this interface is a harmless no-op.
6290 **
6291 ** ^The [wal_checkpoint pragma] can be used to invoke this interface
6292 ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the
6293 ** [wal_autocheckpoint pragma] can be used to cause this interface to be
6294 ** run whenever the WAL reaches a certain size threshold.
6295 **
6296 ** See also: [sqlite3_wal_checkpoint_v2()]
6297 */
6300 /*
6301 ** CAPI3REF: Checkpoint a database
6302 **
6303 ** Run a checkpoint operation on WAL database zDb attached to database
6304 ** handle db. The specific operation is determined by the value of the
6305 ** eMode parameter:
6306 **
6307 ** <dl>
6308 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
6309 ** Checkpoint as many frames as possible without waiting for any database
6310 ** readers or writers to finish. Sync the db file if all frames in the log
6311 ** are checkpointed. This mode is the same as calling
6312 ** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked.
6313 **
6314 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
6315 ** This mode blocks (calls the busy-handler callback) until there is no
6316 ** database writer and all readers are reading from the most recent database
6317 ** snapshot. It then checkpoints all frames in the log file and syncs the
6318 ** database file. This call blocks database writers while it is running,
6319 ** but not database readers.
6320 **
6321 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
6322 ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after
6323 ** checkpointing the log file it blocks (calls the busy-handler callback)
6324 ** until all readers are reading from the database file only. This ensures
6325 ** that the next client to write to the database file restarts the log file
6326 ** from the beginning. This call blocks database writers while it is running,
6327 ** but not database readers.
6328 ** </dl>
6329 **
6330 ** If pnLog is not NULL, then *pnLog is set to the total number of frames in
6331 ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
6332 ** the total number of checkpointed frames (including any that were already
6333 ** checkpointed when this function is called). *pnLog and *pnCkpt may be
6334 ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
6335 ** If no values are available because of an error, they are both set to -1
6336 ** before returning to communicate this to the caller.
6337 **
6338 ** All calls obtain an exclusive "checkpoint" lock on the database file. If
6339 ** any other process is running a checkpoint operation at the same time, the
6340 ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a
6341 ** busy-handler configured, it will not be invoked in this case.
6342 **
6343 ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive
6344 ** "writer" lock on the database file. If the writer lock cannot be obtained
6345 ** immediately, and a busy-handler is configured, it is invoked and the writer
6346 ** lock retried until either the busy-handler returns 0 or the lock is
6347 ** successfully obtained. The busy-handler is also invoked while waiting for
6348 ** database readers as described above. If the busy-handler returns 0 before
6349 ** the writer lock is obtained or while waiting for database readers, the
6350 ** checkpoint operation proceeds from that point in the same way as
6351 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
6352 ** without blocking any further. SQLITE_BUSY is returned in this case.
6353 **
6354 ** If parameter zDb is NULL or points to a zero length string, then the
6355 ** specified operation is attempted on all WAL databases. In this case the
6356 ** values written to output parameters *pnLog and *pnCkpt are undefined. If
6357 ** an SQLITE_BUSY error is encountered when processing one or more of the
6358 ** attached WAL databases, the operation is still attempted on any remaining
6359 ** attached databases and SQLITE_BUSY is returned to the caller. If any other
6360 ** error occurs while processing an attached database, processing is abandoned
6361 ** and the error code returned to the caller immediately. If no error
6362 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
6363 ** databases, SQLITE_OK is returned.
6364 **
6365 ** If database zDb is the name of an attached database that is not in WAL
6366 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
6367 ** zDb is not NULL (or a zero length string) and is not the name of any
6368 ** attached database, SQLITE_ERROR is returned to the caller.
6369 */
6376 );
6378 /*
6379 ** CAPI3REF: Checkpoint operation parameters
6380 **
6381 ** These constants can be used as the 3rd parameter to
6382 ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()]
6383 ** documentation for additional information about the meaning and use of
6384 ** each of these values.
6385 */
6386 #define SQLITE_CHECKPOINT_PASSIVE 0
6387 #define SQLITE_CHECKPOINT_FULL 1
6388 #define SQLITE_CHECKPOINT_RESTART 2
6391 /*
6392 ** Undo the hack that converts floating point types to integer for
6393 ** builds on processors without floating point support.
6394 */
6395 #ifdef SQLITE_OMIT_FLOATING_POINT
6396 # undef double
6397 #endif
6399 #ifdef __cplusplus
6401 #endif
6402 #endif