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Issue 3108030: Move bundled copy of sqlite one level deeper to better separate it... (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src/
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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_
35 #include <stdarg.h> /* Needed for the definition of va_list */
36
37 /*
38 ** Make sure we can call this stuff from C++.
39 */
40 #ifdef __cplusplus
41 extern "C" {
42 #endif
43
44
45 /*
46 ** Add the ability to override 'extern'
47 */
48 #ifndef SQLITE_EXTERN
49 # define SQLITE_EXTERN extern
50 #endif
51
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
67
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
77
78 /*
79 ** CAPI3REF: Compile-Time Library Version Numbers {H10010} <S60100>
80 **
81 ** The SQLITE_VERSION and SQLITE_VERSION_NUMBER #defines in
82 ** the sqlite3.h file specify the version of SQLite with which
83 ** that header file is associated.
84 **
85 ** The "version" of SQLite is a string of the form "W.X.Y" or "W.X.Y.Z".
86 ** The W value is major version number and is always 3 in SQLite3.
87 ** The W value only changes when backwards compatibility is
88 ** broken and we intend to never break backwards compatibility.
89 ** The X value is the minor version number and only changes when
90 ** there are major feature enhancements that are forwards compatible
91 ** but not backwards compatible.
92 ** The Y value is the release number and is incremented with
93 ** each release but resets back to 0 whenever X is incremented.
94 ** The Z value only appears on branch releases.
95 **
96 ** The SQLITE_VERSION_NUMBER is an integer that is computed as
97 ** follows:
98 **
99 ** <blockquote><pre>
100 ** SQLITE_VERSION_NUMBER = W*1000000 + X*1000 + Y
101 ** </pre></blockquote>
102 **
103 ** Since version 3.6.18, SQLite source code has been stored in the
104 ** <a href="http://www.fossil-scm.org/">fossil configuration management
105 ** system</a>. The SQLITE_SOURCE_ID
106 ** macro is a string which identifies a particular check-in of SQLite
107 ** within its configuration management system. The string contains the
108 ** date and time of the check-in (UTC) and an SHA1 hash of the entire
109 ** source tree.
110 **
111 ** See also: [sqlite3_libversion()],
112 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
113 ** [sqlite_version()] and [sqlite_source_id()].
114 **
115 ** Requirements: [H10011] [H10014]
116 */
117 #define SQLITE_VERSION "--VERS--"
118 #define SQLITE_VERSION_NUMBER --VERSION-NUMBER--
119 #define SQLITE_SOURCE_ID "--SOURCE-ID--"
120
121 /*
122 ** CAPI3REF: Run-Time Library Version Numbers {H10020} <S60100>
123 ** KEYWORDS: sqlite3_version
124 **
125 ** These interfaces provide the same information as the [SQLITE_VERSION],
126 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] #defines in the header,
127 ** but are associated with the library instead of the header file. Cautious
128 ** programmers might include assert() statements in their application to
129 ** verify that values returned by these interfaces match the macros in
130 ** the header, and thus insure that the application is
131 ** compiled with matching library and header files.
132 **
133 ** <blockquote><pre>
134 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
135 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
136 ** assert( strcmp(sqlite3_libversion,SQLITE_VERSION)==0 );
137 ** </pre></blockquote>
138 **
139 ** The sqlite3_libversion() function returns the same information as is
140 ** in the sqlite3_version[] string constant. The function is provided
141 ** for use in DLLs since DLL users usually do not have direct access to string
142 ** constants within the DLL. Similarly, the sqlite3_sourceid() function
143 ** returns the same information as is in the [SQLITE_SOURCE_ID] #define of
144 ** the header file.
145 **
146 ** See also: [sqlite_version()] and [sqlite_source_id()].
147 **
148 ** Requirements: [H10021] [H10022] [H10023]
149 */
150 SQLITE_EXTERN const char sqlite3_version[];
151 const char *sqlite3_libversion(void);
152 const char *sqlite3_sourceid(void);
153 int sqlite3_libversion_number(void);
154
155 /*
156 ** CAPI3REF: Test To See If The Library Is Threadsafe {H10100} <S60100>
157 **
158 ** SQLite can be compiled with or without mutexes. When
159 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
160 ** are enabled and SQLite is threadsafe. When the
161 ** [SQLITE_THREADSAFE] macro is 0,
162 ** the mutexes are omitted. Without the mutexes, it is not safe
163 ** to use SQLite concurrently from more than one thread.
164 **
165 ** Enabling mutexes incurs a measurable performance penalty.
166 ** So if speed is of utmost importance, it makes sense to disable
167 ** the mutexes. But for maximum safety, mutexes should be enabled.
168 ** The default behavior is for mutexes to be enabled.
169 **
170 ** This interface can be used by an application to make sure that the
171 ** version of SQLite that it is linking against was compiled with
172 ** the desired setting of the [SQLITE_THREADSAFE] macro.
173 **
174 ** This interface only reports on the compile-time mutex setting
175 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
176 ** SQLITE_THREADSAFE=1 then mutexes are enabled by default but
177 ** can be fully or partially disabled using a call to [sqlite3_config()]
178 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
179 ** or [SQLITE_CONFIG_MUTEX]. The return value of this function shows
180 ** only the default compile-time setting, not any run-time changes
181 ** to that setting.
182 **
183 ** See the [threading mode] documentation for additional information.
184 **
185 ** Requirements: [H10101] [H10102]
186 */
187 int sqlite3_threadsafe(void);
188
189 /*
190 ** CAPI3REF: Database Connection Handle {H12000} <S40200>
191 ** KEYWORDS: {database connection} {database connections}
192 **
193 ** Each open SQLite database is represented by a pointer to an instance of
194 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3
195 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
196 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
197 ** is its destructor. There are many other interfaces (such as
198 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
199 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
200 ** sqlite3 object.
201 */
202 typedef struct sqlite3 sqlite3;
203
204 /*
205 ** CAPI3REF: 64-Bit Integer Types {H10200} <S10110>
206 ** KEYWORDS: sqlite_int64 sqlite_uint64
207 **
208 ** Because there is no cross-platform way to specify 64-bit integer types
209 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
210 **
211 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
212 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
213 ** compatibility only.
214 **
215 ** Requirements: [H10201] [H10202]
216 */
217 #ifdef SQLITE_INT64_TYPE
218 typedef SQLITE_INT64_TYPE sqlite_int64;
219 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
220 #elif defined(_MSC_VER) || defined(__BORLANDC__)
221 typedef __int64 sqlite_int64;
222 typedef unsigned __int64 sqlite_uint64;
223 #else
224 typedef long long int sqlite_int64;
225 typedef unsigned long long int sqlite_uint64;
226 #endif
227 typedef sqlite_int64 sqlite3_int64;
228 typedef sqlite_uint64 sqlite3_uint64;
229
230 /*
231 ** If compiling for a processor that lacks floating point support,
232 ** substitute integer for floating-point.
233 */
234 #ifdef SQLITE_OMIT_FLOATING_POINT
235 # define double sqlite3_int64
236 #endif
237
238 /*
239 ** CAPI3REF: Closing A Database Connection {H12010} <S30100><S40200>
240 **
241 ** This routine is the destructor for the [sqlite3] object.
242 **
243 ** Applications should [sqlite3_finalize | finalize] all [prepared statements]
244 ** and [sqlite3_blob_close | close] all [BLOB handles] associated with
245 ** the [sqlite3] object prior to attempting to close the object.
246 ** The [sqlite3_next_stmt()] interface can be used to locate all
247 ** [prepared statements] associated with a [database connection] if desired.
248 ** Typical code might look like this:
249 **
250 ** <blockquote><pre>
251 ** sqlite3_stmt *pStmt;
252 ** while( (pStmt = sqlite3_next_stmt(db, 0))!=0 ){
253 ** &nbsp; sqlite3_finalize(pStmt);
254 ** }
255 ** </pre></blockquote>
256 **
257 ** If [sqlite3_close()] is invoked while a transaction is open,
258 ** the transaction is automatically rolled back.
259 **
260 ** The C parameter to [sqlite3_close(C)] must be either a NULL
261 ** pointer or an [sqlite3] object pointer obtained
262 ** from [sqlite3_open()], [sqlite3_open16()], or
263 ** [sqlite3_open_v2()], and not previously closed.
264 **
265 ** Requirements:
266 ** [H12011] [H12012] [H12013] [H12014] [H12015] [H12019]
267 */
268 int sqlite3_close(sqlite3 *);
269
270 /*
271 ** The type for a callback function.
272 ** This is legacy and deprecated. It is included for historical
273 ** compatibility and is not documented.
274 */
275 typedef int (*sqlite3_callback)(void*,int,char**, char**);
276
277 /*
278 ** CAPI3REF: One-Step Query Execution Interface {H12100} <S10000>
279 **
280 ** The sqlite3_exec() interface is a convenient way of running one or more
281 ** SQL statements without having to write a lot of C code. The UTF-8 encoded
282 ** SQL statements are passed in as the second parameter to sqlite3_exec().
283 ** The statements are evaluated one by one until either an error or
284 ** an interrupt is encountered, or until they are all done. The 3rd parameter
285 ** is an optional callback that is invoked once for each row of any query
286 ** results produced by the SQL statements. The 5th parameter tells where
287 ** to write any error messages.
288 **
289 ** The error message passed back through the 5th parameter is held
290 ** in memory obtained from [sqlite3_malloc()]. To avoid a memory leak,
291 ** the calling application should call [sqlite3_free()] on any error
292 ** message returned through the 5th parameter when it has finished using
293 ** the error message.
294 **
295 ** If the SQL statement in the 2nd parameter is NULL or an empty string
296 ** or a string containing only whitespace and comments, then no SQL
297 ** statements are evaluated and the database is not changed.
298 **
299 ** The sqlite3_exec() interface is implemented in terms of
300 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()].
301 ** The sqlite3_exec() routine does nothing to the database that cannot be done
302 ** by [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()].
303 **
304 ** The first parameter to [sqlite3_exec()] must be an valid and open
305 ** [database connection].
306 **
307 ** The database connection must not be closed while
308 ** [sqlite3_exec()] is running.
309 **
310 ** The calling function should use [sqlite3_free()] to free
311 ** the memory that *errmsg is left pointing at once the error
312 ** message is no longer needed.
313 **
314 ** The SQL statement text in the 2nd parameter to [sqlite3_exec()]
315 ** must remain unchanged while [sqlite3_exec()] is running.
316 **
317 ** Requirements:
318 ** [H12101] [H12102] [H12104] [H12105] [H12107] [H12110] [H12113] [H12116]
319 ** [H12119] [H12122] [H12125] [H12131] [H12134] [H12137] [H12138]
320 */
321 int sqlite3_exec(
322 sqlite3*, /* An open database */
323 const char *sql, /* SQL to be evaluated */
324 int (*callback)(void*,int,char**,char**), /* Callback function */
325 void *, /* 1st argument to callback */
326 char **errmsg /* Error msg written here */
327 );
328
329 /*
330 ** CAPI3REF: Result Codes {H10210} <S10700>
331 ** KEYWORDS: SQLITE_OK {error code} {error codes}
332 ** KEYWORDS: {result code} {result codes}
333 **
334 ** Many SQLite functions return an integer result code from the set shown
335 ** here in order to indicates success or failure.
336 **
337 ** New error codes may be added in future versions of SQLite.
338 **
339 ** See also: [SQLITE_IOERR_READ | extended result codes]
340 */
341 #define SQLITE_OK 0 /* Successful result */
342 /* beginning-of-error-codes */
343 #define SQLITE_ERROR 1 /* SQL error or missing database */
344 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
345 #define SQLITE_PERM 3 /* Access permission denied */
346 #define SQLITE_ABORT 4 /* Callback routine requested an abort */
347 #define SQLITE_BUSY 5 /* The database file is locked */
348 #define SQLITE_LOCKED 6 /* A table in the database is locked */
349 #define SQLITE_NOMEM 7 /* A malloc() failed */
350 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */
351 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
352 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
353 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */
354 #define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */
355 #define SQLITE_FULL 13 /* Insertion failed because database is full */
356 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */
357 #define SQLITE_PROTOCOL 15 /* NOT USED. Database lock protocol error */
358 #define SQLITE_EMPTY 16 /* Database is empty */
359 #define SQLITE_SCHEMA 17 /* The database schema changed */
360 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
361 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
362 #define SQLITE_MISMATCH 20 /* Data type mismatch */
363 #define SQLITE_MISUSE 21 /* Library used incorrectly */
364 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
365 #define SQLITE_AUTH 23 /* Authorization denied */
366 #define SQLITE_FORMAT 24 /* Auxiliary database format error */
367 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
368 #define SQLITE_NOTADB 26 /* File opened that is not a database file */
369 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
370 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
371 /* end-of-error-codes */
372
373 /*
374 ** CAPI3REF: Extended Result Codes {H10220} <S10700>
375 ** KEYWORDS: {extended error code} {extended error codes}
376 ** KEYWORDS: {extended result code} {extended result codes}
377 **
378 ** In its default configuration, SQLite API routines return one of 26 integer
379 ** [SQLITE_OK | result codes]. However, experience has shown that many of
380 ** these result codes are too coarse-grained. They do not provide as
381 ** much information about problems as programmers might like. In an effort to
382 ** address this, newer versions of SQLite (version 3.3.8 and later) include
383 ** support for additional result codes that provide more detailed information
384 ** about errors. The extended result codes are enabled or disabled
385 ** on a per database connection basis using the
386 ** [sqlite3_extended_result_codes()] API.
387 **
388 ** Some of the available extended result codes are listed here.
389 ** One may expect the number of extended result codes will be expand
390 ** over time. Software that uses extended result codes should expect
391 ** to see new result codes in future releases of SQLite.
392 **
393 ** The SQLITE_OK result code will never be extended. It will always
394 ** be exactly zero.
395 */
396 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
397 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
398 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
399 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
400 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
401 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
402 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
403 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
404 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
405 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
406 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
407 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
408 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
409 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
410 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
411 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
412 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
413 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8) )
414
415 /*
416 ** CAPI3REF: Flags For File Open Operations {H10230} <H11120> <H12700>
417 **
418 ** These bit values are intended for use in the
419 ** 3rd parameter to the [sqlite3_open_v2()] interface and
420 ** in the 4th parameter to the xOpen method of the
421 ** [sqlite3_vfs] object.
422 */
423 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
424 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
425 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
426 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
427 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
428 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
429 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
430 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
431 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
432 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
433 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
434 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
435 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
436 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
437 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
438 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
439
440 /*
441 ** CAPI3REF: Device Characteristics {H10240} <H11120>
442 **
443 ** The xDeviceCapabilities method of the [sqlite3_io_methods]
444 ** object returns an integer which is a vector of the these
445 ** bit values expressing I/O characteristics of the mass storage
446 ** device that holds the file that the [sqlite3_io_methods]
447 ** refers to.
448 **
449 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
450 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
451 ** mean that writes of blocks that are nnn bytes in size and
452 ** are aligned to an address which is an integer multiple of
453 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
454 ** that when data is appended to a file, the data is appended
455 ** first then the size of the file is extended, never the other
456 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
457 ** information is written to disk in the same order as calls
458 ** to xWrite().
459 */
460 #define SQLITE_IOCAP_ATOMIC 0x00000001
461 #define SQLITE_IOCAP_ATOMIC512 0x00000002
462 #define SQLITE_IOCAP_ATOMIC1K 0x00000004
463 #define SQLITE_IOCAP_ATOMIC2K 0x00000008
464 #define SQLITE_IOCAP_ATOMIC4K 0x00000010
465 #define SQLITE_IOCAP_ATOMIC8K 0x00000020
466 #define SQLITE_IOCAP_ATOMIC16K 0x00000040
467 #define SQLITE_IOCAP_ATOMIC32K 0x00000080
468 #define SQLITE_IOCAP_ATOMIC64K 0x00000100
469 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
470 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
471
472 /*
473 ** CAPI3REF: File Locking Levels {H10250} <H11120> <H11310>
474 **
475 ** SQLite uses one of these integer values as the second
476 ** argument to calls it makes to the xLock() and xUnlock() methods
477 ** of an [sqlite3_io_methods] object.
478 */
479 #define SQLITE_LOCK_NONE 0
480 #define SQLITE_LOCK_SHARED 1
481 #define SQLITE_LOCK_RESERVED 2
482 #define SQLITE_LOCK_PENDING 3
483 #define SQLITE_LOCK_EXCLUSIVE 4
484
485 /*
486 ** CAPI3REF: Synchronization Type Flags {H10260} <H11120>
487 **
488 ** When SQLite invokes the xSync() method of an
489 ** [sqlite3_io_methods] object it uses a combination of
490 ** these integer values as the second argument.
491 **
492 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
493 ** sync operation only needs to flush data to mass storage. Inode
494 ** information need not be flushed. If the lower four bits of the flag
495 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
496 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
497 ** to use Mac OS X style fullsync instead of fsync().
498 */
499 #define SQLITE_SYNC_NORMAL 0x00002
500 #define SQLITE_SYNC_FULL 0x00003
501 #define SQLITE_SYNC_DATAONLY 0x00010
502
503 /*
504 ** CAPI3REF: OS Interface Open File Handle {H11110} <S20110>
505 **
506 ** An [sqlite3_file] object represents an open file in the
507 ** [sqlite3_vfs | OS interface layer]. Individual OS interface
508 ** implementations will
509 ** want to subclass this object by appending additional fields
510 ** for their own use. The pMethods entry is a pointer to an
511 ** [sqlite3_io_methods] object that defines methods for performing
512 ** I/O operations on the open file.
513 */
514 typedef struct sqlite3_file sqlite3_file;
515 struct sqlite3_file {
516 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
517 };
518
519 /*
520 ** CAPI3REF: OS Interface File Virtual Methods Object {H11120} <S20110>
521 **
522 ** Every file opened by the [sqlite3_vfs] xOpen method populates an
523 ** [sqlite3_file] object (or, more commonly, a subclass of the
524 ** [sqlite3_file] object) with a pointer to an instance of this object.
525 ** This object defines the methods used to perform various operations
526 ** against the open file represented by the [sqlite3_file] object.
527 **
528 ** If the xOpen method sets the sqlite3_file.pMethods element
529 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
530 ** may be invoked even if the xOpen reported that it failed. The
531 ** only way to prevent a call to xClose following a failed xOpen
532 ** is for the xOpen to set the sqlite3_file.pMethods element to NULL.
533 **
534 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
535 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
536 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
537 ** flag may be ORed in to indicate that only the data of the file
538 ** and not its inode needs to be synced.
539 **
540 ** The integer values to xLock() and xUnlock() are one of
541 ** <ul>
542 ** <li> [SQLITE_LOCK_NONE],
543 ** <li> [SQLITE_LOCK_SHARED],
544 ** <li> [SQLITE_LOCK_RESERVED],
545 ** <li> [SQLITE_LOCK_PENDING], or
546 ** <li> [SQLITE_LOCK_EXCLUSIVE].
547 ** </ul>
548 ** xLock() increases the lock. xUnlock() decreases the lock.
549 ** The xCheckReservedLock() method checks whether any database connection,
550 ** either in this process or in some other process, is holding a RESERVED,
551 ** PENDING, or EXCLUSIVE lock on the file. It returns true
552 ** if such a lock exists and false otherwise.
553 **
554 ** The xFileControl() method is a generic interface that allows custom
555 ** VFS implementations to directly control an open file using the
556 ** [sqlite3_file_control()] interface. The second "op" argument is an
557 ** integer opcode. The third argument is a generic pointer intended to
558 ** point to a structure that may contain arguments or space in which to
559 ** write return values. Potential uses for xFileControl() might be
560 ** functions to enable blocking locks with timeouts, to change the
561 ** locking strategy (for example to use dot-file locks), to inquire
562 ** about the status of a lock, or to break stale locks. The SQLite
563 ** core reserves all opcodes less than 100 for its own use.
564 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
565 ** Applications that define a custom xFileControl method should use opcodes
566 ** greater than 100 to avoid conflicts.
567 **
568 ** The xSectorSize() method returns the sector size of the
569 ** device that underlies the file. The sector size is the
570 ** minimum write that can be performed without disturbing
571 ** other bytes in the file. The xDeviceCharacteristics()
572 ** method returns a bit vector describing behaviors of the
573 ** underlying device:
574 **
575 ** <ul>
576 ** <li> [SQLITE_IOCAP_ATOMIC]
577 ** <li> [SQLITE_IOCAP_ATOMIC512]
578 ** <li> [SQLITE_IOCAP_ATOMIC1K]
579 ** <li> [SQLITE_IOCAP_ATOMIC2K]
580 ** <li> [SQLITE_IOCAP_ATOMIC4K]
581 ** <li> [SQLITE_IOCAP_ATOMIC8K]
582 ** <li> [SQLITE_IOCAP_ATOMIC16K]
583 ** <li> [SQLITE_IOCAP_ATOMIC32K]
584 ** <li> [SQLITE_IOCAP_ATOMIC64K]
585 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
586 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
587 ** </ul>
588 **
589 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
590 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
591 ** mean that writes of blocks that are nnn bytes in size and
592 ** are aligned to an address which is an integer multiple of
593 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
594 ** that when data is appended to a file, the data is appended
595 ** first then the size of the file is extended, never the other
596 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
597 ** information is written to disk in the same order as calls
598 ** to xWrite().
599 **
600 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
601 ** in the unread portions of the buffer with zeros. A VFS that
602 ** fails to zero-fill short reads might seem to work. However,
603 ** failure to zero-fill short reads will eventually lead to
604 ** database corruption.
605 */
606 typedef struct sqlite3_io_methods sqlite3_io_methods;
607 struct sqlite3_io_methods {
608 int iVersion;
609 int (*xClose)(sqlite3_file*);
610 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
611 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
612 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
613 int (*xSync)(sqlite3_file*, int flags);
614 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
615 int (*xLock)(sqlite3_file*, int);
616 int (*xUnlock)(sqlite3_file*, int);
617 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
618 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
619 int (*xSectorSize)(sqlite3_file*);
620 int (*xDeviceCharacteristics)(sqlite3_file*);
621 /* Additional methods may be added in future releases */
622 };
623
624 /*
625 ** CAPI3REF: Standard File Control Opcodes {H11310} <S30800>
626 **
627 ** These integer constants are opcodes for the xFileControl method
628 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
629 ** interface.
630 **
631 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
632 ** opcode causes the xFileControl method to write the current state of
633 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
634 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
635 ** into an integer that the pArg argument points to. This capability
636 ** is used during testing and only needs to be supported when SQLITE_TEST
637 ** is defined.
638 */
639 #define SQLITE_FCNTL_LOCKSTATE 1
640 #define SQLITE_GET_LOCKPROXYFILE 2
641 #define SQLITE_SET_LOCKPROXYFILE 3
642 #define SQLITE_LAST_ERRNO 4
643
644 /*
645 ** CAPI3REF: Mutex Handle {H17110} <S20130>
646 **
647 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
648 ** abstract type for a mutex object. The SQLite core never looks
649 ** at the internal representation of an [sqlite3_mutex]. It only
650 ** deals with pointers to the [sqlite3_mutex] object.
651 **
652 ** Mutexes are created using [sqlite3_mutex_alloc()].
653 */
654 typedef struct sqlite3_mutex sqlite3_mutex;
655
656 /*
657 ** CAPI3REF: OS Interface Object {H11140} <S20100>
658 **
659 ** An instance of the sqlite3_vfs object defines the interface between
660 ** the SQLite core and the underlying operating system. The "vfs"
661 ** in the name of the object stands for "virtual file system".
662 **
663 ** The value of the iVersion field is initially 1 but may be larger in
664 ** future versions of SQLite. Additional fields may be appended to this
665 ** object when the iVersion value is increased. Note that the structure
666 ** of the sqlite3_vfs object changes in the transaction between
667 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
668 ** modified.
669 **
670 ** The szOsFile field is the size of the subclassed [sqlite3_file]
671 ** structure used by this VFS. mxPathname is the maximum length of
672 ** a pathname in this VFS.
673 **
674 ** Registered sqlite3_vfs objects are kept on a linked list formed by
675 ** the pNext pointer. The [sqlite3_vfs_register()]
676 ** and [sqlite3_vfs_unregister()] interfaces manage this list
677 ** in a thread-safe way. The [sqlite3_vfs_find()] interface
678 ** searches the list. Neither the application code nor the VFS
679 ** implementation should use the pNext pointer.
680 **
681 ** The pNext field is the only field in the sqlite3_vfs
682 ** structure that SQLite will ever modify. SQLite will only access
683 ** or modify this field while holding a particular static mutex.
684 ** The application should never modify anything within the sqlite3_vfs
685 ** object once the object has been registered.
686 **
687 ** The zName field holds the name of the VFS module. The name must
688 ** be unique across all VFS modules.
689 **
690 ** SQLite will guarantee that the zFilename parameter to xOpen
691 ** is either a NULL pointer or string obtained
692 ** from xFullPathname(). SQLite further guarantees that
693 ** the string will be valid and unchanged until xClose() is
694 ** called. Because of the previous sentence,
695 ** the [sqlite3_file] can safely store a pointer to the
696 ** filename if it needs to remember the filename for some reason.
697 ** If the zFilename parameter is xOpen is a NULL pointer then xOpen
698 ** must invent its own temporary name for the file. Whenever the
699 ** xFilename parameter is NULL it will also be the case that the
700 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
701 **
702 ** The flags argument to xOpen() includes all bits set in
703 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
704 ** or [sqlite3_open16()] is used, then flags includes at least
705 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
706 ** If xOpen() opens a file read-only then it sets *pOutFlags to
707 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
708 **
709 ** SQLite will also add one of the following flags to the xOpen()
710 ** call, depending on the object being opened:
711 **
712 ** <ul>
713 ** <li> [SQLITE_OPEN_MAIN_DB]
714 ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
715 ** <li> [SQLITE_OPEN_TEMP_DB]
716 ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
717 ** <li> [SQLITE_OPEN_TRANSIENT_DB]
718 ** <li> [SQLITE_OPEN_SUBJOURNAL]
719 ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
720 ** </ul>
721 **
722 ** The file I/O implementation can use the object type flags to
723 ** change the way it deals with files. For example, an application
724 ** that does not care about crash recovery or rollback might make
725 ** the open of a journal file a no-op. Writes to this journal would
726 ** also be no-ops, and any attempt to read the journal would return
727 ** SQLITE_IOERR. Or the implementation might recognize that a database
728 ** file will be doing page-aligned sector reads and writes in a random
729 ** order and set up its I/O subsystem accordingly.
730 **
731 ** SQLite might also add one of the following flags to the xOpen method:
732 **
733 ** <ul>
734 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
735 ** <li> [SQLITE_OPEN_EXCLUSIVE]
736 ** </ul>
737 **
738 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
739 ** deleted when it is closed. The [SQLITE_OPEN_DELETEONCLOSE]
740 ** will be set for TEMP databases, journals and for subjournals.
741 **
742 ** The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
743 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
744 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
745 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
746 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
747 ** be created, and that it is an error if it already exists.
748 ** It is <i>not</i> used to indicate the file should be opened
749 ** for exclusive access.
750 **
751 ** At least szOsFile bytes of memory are allocated by SQLite
752 ** to hold the [sqlite3_file] structure passed as the third
753 ** argument to xOpen. The xOpen method does not have to
754 ** allocate the structure; it should just fill it in. Note that
755 ** the xOpen method must set the sqlite3_file.pMethods to either
756 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
757 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
758 ** element will be valid after xOpen returns regardless of the success
759 ** or failure of the xOpen call.
760 **
761 ** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
762 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
763 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
764 ** to test whether a file is at least readable. The file can be a
765 ** directory.
766 **
767 ** SQLite will always allocate at least mxPathname+1 bytes for the
768 ** output buffer xFullPathname. The exact size of the output buffer
769 ** is also passed as a parameter to both methods. If the output buffer
770 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
771 ** handled as a fatal error by SQLite, vfs implementations should endeavor
772 ** to prevent this by setting mxPathname to a sufficiently large value.
773 **
774 ** The xRandomness(), xSleep(), and xCurrentTime() interfaces
775 ** are not strictly a part of the filesystem, but they are
776 ** included in the VFS structure for completeness.
777 ** The xRandomness() function attempts to return nBytes bytes
778 ** of good-quality randomness into zOut. The return value is
779 ** the actual number of bytes of randomness obtained.
780 ** The xSleep() method causes the calling thread to sleep for at
781 ** least the number of microseconds given. The xCurrentTime()
782 ** method returns a Julian Day Number for the current date and time.
783 **
784 */
785 typedef struct sqlite3_vfs sqlite3_vfs;
786 struct sqlite3_vfs {
787 int iVersion; /* Structure version number */
788 int szOsFile; /* Size of subclassed sqlite3_file */
789 int mxPathname; /* Maximum file pathname length */
790 sqlite3_vfs *pNext; /* Next registered VFS */
791 const char *zName; /* Name of this virtual file system */
792 void *pAppData; /* Pointer to application-specific data */
793 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
794 int flags, int *pOutFlags);
795 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
796 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
797 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
798 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
799 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
800 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
801 void (*xDlClose)(sqlite3_vfs*, void*);
802 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
803 int (*xSleep)(sqlite3_vfs*, int microseconds);
804 int (*xCurrentTime)(sqlite3_vfs*, double*);
805 int (*xGetLastError)(sqlite3_vfs*, int, char *);
806 /* New fields may be appended in figure versions. The iVersion
807 ** value will increment whenever this happens. */
808 };
809
810 /*
811 ** CAPI3REF: Flags for the xAccess VFS method {H11190} <H11140>
812 **
813 ** These integer constants can be used as the third parameter to
814 ** the xAccess method of an [sqlite3_vfs] object. {END} They determine
815 ** what kind of permissions the xAccess method is looking for.
816 ** With SQLITE_ACCESS_EXISTS, the xAccess method
817 ** simply checks whether the file exists.
818 ** With SQLITE_ACCESS_READWRITE, the xAccess method
819 ** checks whether the file is both readable and writable.
820 ** With SQLITE_ACCESS_READ, the xAccess method
821 ** checks whether the file is readable.
822 */
823 #define SQLITE_ACCESS_EXISTS 0
824 #define SQLITE_ACCESS_READWRITE 1
825 #define SQLITE_ACCESS_READ 2
826
827 /*
828 ** CAPI3REF: Initialize The SQLite Library {H10130} <S20000><S30100>
829 **
830 ** The sqlite3_initialize() routine initializes the
831 ** SQLite library. The sqlite3_shutdown() routine
832 ** deallocates any resources that were allocated by sqlite3_initialize().
833 **
834 ** A call to sqlite3_initialize() is an "effective" call if it is
835 ** the first time sqlite3_initialize() is invoked during the lifetime of
836 ** the process, or if it is the first time sqlite3_initialize() is invoked
837 ** following a call to sqlite3_shutdown(). Only an effective call
838 ** of sqlite3_initialize() does any initialization. All other calls
839 ** are harmless no-ops.
840 **
841 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
842 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). Only
843 ** an effective call to sqlite3_shutdown() does any deinitialization.
844 ** All other calls to sqlite3_shutdown() are harmless no-ops.
845 **
846 ** Among other things, sqlite3_initialize() shall invoke
847 ** sqlite3_os_init(). Similarly, sqlite3_shutdown()
848 ** shall invoke sqlite3_os_end().
849 **
850 ** The sqlite3_initialize() routine returns [SQLITE_OK] on success.
851 ** If for some reason, sqlite3_initialize() is unable to initialize
852 ** the library (perhaps it is unable to allocate a needed resource such
853 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
854 **
855 ** The sqlite3_initialize() routine is called internally by many other
856 ** SQLite interfaces so that an application usually does not need to
857 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
858 ** calls sqlite3_initialize() so the SQLite library will be automatically
859 ** initialized when [sqlite3_open()] is called if it has not be initialized
860 ** already. However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
861 ** compile-time option, then the automatic calls to sqlite3_initialize()
862 ** are omitted and the application must call sqlite3_initialize() directly
863 ** prior to using any other SQLite interface. For maximum portability,
864 ** it is recommended that applications always invoke sqlite3_initialize()
865 ** directly prior to using any other SQLite interface. Future releases
866 ** of SQLite may require this. In other words, the behavior exhibited
867 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
868 ** default behavior in some future release of SQLite.
869 **
870 ** The sqlite3_os_init() routine does operating-system specific
871 ** initialization of the SQLite library. The sqlite3_os_end()
872 ** routine undoes the effect of sqlite3_os_init(). Typical tasks
873 ** performed by these routines include allocation or deallocation
874 ** of static resources, initialization of global variables,
875 ** setting up a default [sqlite3_vfs] module, or setting up
876 ** a default configuration using [sqlite3_config()].
877 **
878 ** The application should never invoke either sqlite3_os_init()
879 ** or sqlite3_os_end() directly. The application should only invoke
880 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
881 ** interface is called automatically by sqlite3_initialize() and
882 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
883 ** implementations for sqlite3_os_init() and sqlite3_os_end()
884 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
885 ** When [custom builds | built for other platforms]
886 ** (using the [SQLITE_OS_OTHER=1] compile-time
887 ** option) the application must supply a suitable implementation for
888 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
889 ** implementation of sqlite3_os_init() or sqlite3_os_end()
890 ** must return [SQLITE_OK] on success and some other [error code] upon
891 ** failure.
892 */
893 int sqlite3_initialize(void);
894 int sqlite3_shutdown(void);
895 int sqlite3_os_init(void);
896 int sqlite3_os_end(void);
897
898 /*
899 ** CAPI3REF: Configuring The SQLite Library {H14100} <S20000><S30200>
900 ** EXPERIMENTAL
901 **
902 ** The sqlite3_config() interface is used to make global configuration
903 ** changes to SQLite in order to tune SQLite to the specific needs of
904 ** the application. The default configuration is recommended for most
905 ** applications and so this routine is usually not necessary. It is
906 ** provided to support rare applications with unusual needs.
907 **
908 ** The sqlite3_config() interface is not threadsafe. The application
909 ** must insure that no other SQLite interfaces are invoked by other
910 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config()
911 ** may only be invoked prior to library initialization using
912 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
913 ** Note, however, that sqlite3_config() can be called as part of the
914 ** implementation of an application-defined [sqlite3_os_init()].
915 **
916 ** The first argument to sqlite3_config() is an integer
917 ** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines
918 ** what property of SQLite is to be configured. Subsequent arguments
919 ** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option]
920 ** in the first argument.
921 **
922 ** When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
923 ** If the option is unknown or SQLite is unable to set the option
924 ** then this routine returns a non-zero [error code].
925 **
926 ** Requirements:
927 ** [H14103] [H14106] [H14120] [H14123] [H14126] [H14129] [H14132] [H14135]
928 ** [H14138] [H14141] [H14144] [H14147] [H14150] [H14153] [H14156] [H14159]
929 ** [H14162] [H14165] [H14168]
930 */
931 SQLITE_EXPERIMENTAL int sqlite3_config(int, ...);
932
933 /*
934 ** CAPI3REF: Configure database connections {H14200} <S20000>
935 ** EXPERIMENTAL
936 **
937 ** The sqlite3_db_config() interface is used to make configuration
938 ** changes to a [database connection]. The interface is similar to
939 ** [sqlite3_config()] except that the changes apply to a single
940 ** [database connection] (specified in the first argument). The
941 ** sqlite3_db_config() interface can only be used immediately after
942 ** the database connection is created using [sqlite3_open()],
943 ** [sqlite3_open16()], or [sqlite3_open_v2()].
944 **
945 ** The second argument to sqlite3_db_config(D,V,...) is the
946 ** configuration verb - an integer code that indicates what
947 ** aspect of the [database connection] is being configured.
948 ** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE].
949 ** New verbs are likely to be added in future releases of SQLite.
950 ** Additional arguments depend on the verb.
951 **
952 ** Requirements:
953 ** [H14203] [H14206] [H14209] [H14212] [H14215]
954 */
955 SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...);
956
957 /*
958 ** CAPI3REF: Memory Allocation Routines {H10155} <S20120>
959 ** EXPERIMENTAL
960 **
961 ** An instance of this object defines the interface between SQLite
962 ** and low-level memory allocation routines.
963 **
964 ** This object is used in only one place in the SQLite interface.
965 ** A pointer to an instance of this object is the argument to
966 ** [sqlite3_config()] when the configuration option is
967 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
968 ** By creating an instance of this object
969 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
970 ** during configuration, an application can specify an alternative
971 ** memory allocation subsystem for SQLite to use for all of its
972 ** dynamic memory needs.
973 **
974 ** Note that SQLite comes with several [built-in memory allocators]
975 ** that are perfectly adequate for the overwhelming majority of applications
976 ** and that this object is only useful to a tiny minority of applications
977 ** with specialized memory allocation requirements. This object is
978 ** also used during testing of SQLite in order to specify an alternative
979 ** memory allocator that simulates memory out-of-memory conditions in
980 ** order to verify that SQLite recovers gracefully from such
981 ** conditions.
982 **
983 ** The xMalloc and xFree methods must work like the
984 ** malloc() and free() functions from the standard C library.
985 ** The xRealloc method must work like realloc() from the standard C library
986 ** with the exception that if the second argument to xRealloc is zero,
987 ** xRealloc must be a no-op - it must not perform any allocation or
988 ** deallocation. SQLite guaranteeds that the second argument to
989 ** xRealloc is always a value returned by a prior call to xRoundup.
990 ** And so in cases where xRoundup always returns a positive number,
991 ** xRealloc can perform exactly as the standard library realloc() and
992 ** still be in compliance with this specification.
993 **
994 ** xSize should return the allocated size of a memory allocation
995 ** previously obtained from xMalloc or xRealloc. The allocated size
996 ** is always at least as big as the requested size but may be larger.
997 **
998 ** The xRoundup method returns what would be the allocated size of
999 ** a memory allocation given a particular requested size. Most memory
1000 ** allocators round up memory allocations at least to the next multiple
1001 ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1002 ** Every memory allocation request coming in through [sqlite3_malloc()]
1003 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1004 ** that causes the corresponding memory allocation to fail.
1005 **
1006 ** The xInit method initializes the memory allocator. (For example,
1007 ** it might allocate any require mutexes or initialize internal data
1008 ** structures. The xShutdown method is invoked (indirectly) by
1009 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1010 ** by xInit. The pAppData pointer is used as the only parameter to
1011 ** xInit and xShutdown.
1012 **
1013 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1014 ** the xInit method, so the xInit method need not be threadsafe. The
1015 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1016 ** not need to be threadsafe either. For all other methods, SQLite
1017 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1018 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1019 ** it is by default) and so the methods are automatically serialized.
1020 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1021 ** methods must be threadsafe or else make their own arrangements for
1022 ** serialization.
1023 **
1024 ** SQLite will never invoke xInit() more than once without an intervening
1025 ** call to xShutdown().
1026 */
1027 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1028 struct sqlite3_mem_methods {
1029 void *(*xMalloc)(int); /* Memory allocation function */
1030 void (*xFree)(void*); /* Free a prior allocation */
1031 void *(*xRealloc)(void*,int); /* Resize an allocation */
1032 int (*xSize)(void*); /* Return the size of an allocation */
1033 int (*xRoundup)(int); /* Round up request size to allocation size */
1034 int (*xInit)(void*); /* Initialize the memory allocator */
1035 void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1036 void *pAppData; /* Argument to xInit() and xShutdown() */
1037 };
1038
1039 /*
1040 ** CAPI3REF: Configuration Options {H10160} <S20000>
1041 ** EXPERIMENTAL
1042 **
1043 ** These constants are the available integer configuration options that
1044 ** can be passed as the first argument to the [sqlite3_config()] interface.
1045 **
1046 ** New configuration options may be added in future releases of SQLite.
1047 ** Existing configuration options might be discontinued. Applications
1048 ** should check the return code from [sqlite3_config()] to make sure that
1049 ** the call worked. The [sqlite3_config()] interface will return a
1050 ** non-zero [error code] if a discontinued or unsupported configuration option
1051 ** is invoked.
1052 **
1053 ** <dl>
1054 ** <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1055 ** <dd>There are no arguments to this option. This option disables
1056 ** all mutexing and puts SQLite into a mode where it can only be used
1057 ** by a single thread.</dd>
1058 **
1059 ** <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1060 ** <dd>There are no arguments to this option. This option disables
1061 ** mutexing on [database connection] and [prepared statement] objects.
1062 ** The application is responsible for serializing access to
1063 ** [database connections] and [prepared statements]. But other mutexes
1064 ** are enabled so that SQLite will be safe to use in a multi-threaded
1065 ** environment as long as no two threads attempt to use the same
1066 ** [database connection] at the same time. See the [threading mode]
1067 ** documentation for additional information.</dd>
1068 **
1069 ** <dt>SQLITE_CONFIG_SERIALIZED</dt>
1070 ** <dd>There are no arguments to this option. This option enables
1071 ** all mutexes including the recursive
1072 ** mutexes on [database connection] and [prepared statement] objects.
1073 ** In this mode (which is the default when SQLite is compiled with
1074 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1075 ** to [database connections] and [prepared statements] so that the
1076 ** application is free to use the same [database connection] or the
1077 ** same [prepared statement] in different threads at the same time.
1078 ** See the [threading mode] documentation for additional information.</dd>
1079 **
1080 ** <dt>SQLITE_CONFIG_MALLOC</dt>
1081 ** <dd>This option takes a single argument which is a pointer to an
1082 ** instance of the [sqlite3_mem_methods] structure. The argument specifies
1083 ** alternative low-level memory allocation routines to be used in place of
1084 ** the memory allocation routines built into SQLite.</dd>
1085 **
1086 ** <dt>SQLITE_CONFIG_GETMALLOC</dt>
1087 ** <dd>This option takes a single argument which is a pointer to an
1088 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods]
1089 ** structure is filled with the currently defined memory allocation routines.
1090 ** This option can be used to overload the default memory allocation
1091 ** routines with a wrapper that simulations memory allocation failure or
1092 ** tracks memory usage, for example.</dd>
1093 **
1094 ** <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1095 ** <dd>This option takes single argument of type int, interpreted as a
1096 ** boolean, which enables or disables the collection of memory allocation
1097 ** statistics. When disabled, the following SQLite interfaces become
1098 ** non-operational:
1099 ** <ul>
1100 ** <li> [sqlite3_memory_used()]
1101 ** <li> [sqlite3_memory_highwater()]
1102 ** <li> [sqlite3_soft_heap_limit()]
1103 ** <li> [sqlite3_status()]
1104 ** </ul>
1105 ** </dd>
1106 **
1107 ** <dt>SQLITE_CONFIG_SCRATCH</dt>
1108 ** <dd>This option specifies a static memory buffer that SQLite can use for
1109 ** scratch memory. There are three arguments: A pointer an 8-byte
1110 ** aligned memory buffer from which the scrach allocations will be
1111 ** drawn, the size of each scratch allocation (sz),
1112 ** and the maximum number of scratch allocations (N). The sz
1113 ** argument must be a multiple of 16. The sz parameter should be a few bytes
1114 ** larger than the actual scratch space required due to internal overhead.
1115 ** The first argument should pointer to an 8-byte aligned buffer
1116 ** of at least sz*N bytes of memory.
1117 ** SQLite will use no more than one scratch buffer at once per thread, so
1118 ** N should be set to the expected maximum number of threads. The sz
1119 ** parameter should be 6 times the size of the largest database page size.
1120 ** Scratch buffers are used as part of the btree balance operation. If
1121 ** The btree balancer needs additional memory beyond what is provided by
1122 ** scratch buffers or if no scratch buffer space is specified, then SQLite
1123 ** goes to [sqlite3_malloc()] to obtain the memory it needs.</dd>
1124 **
1125 ** <dt>SQLITE_CONFIG_PAGECACHE</dt>
1126 ** <dd>This option specifies a static memory buffer that SQLite can use for
1127 ** the database page cache with the default page cache implemenation.
1128 ** This configuration should not be used if an application-define page
1129 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option.
1130 ** There are three arguments to this option: A pointer to 8-byte aligned
1131 ** memory, the size of each page buffer (sz), and the number of pages (N).
1132 ** The sz argument should be the size of the largest database page
1133 ** (a power of two between 512 and 32768) plus a little extra for each
1134 ** page header. The page header size is 20 to 40 bytes depending on
1135 ** the host architecture. It is harmless, apart from the wasted memory,
1136 ** to make sz a little too large. The first
1137 ** argument should point to an allocation of at least sz*N bytes of memory.
1138 ** SQLite will use the memory provided by the first argument to satisfy its
1139 ** memory needs for the first N pages that it adds to cache. If additional
1140 ** page cache memory is needed beyond what is provided by this option, then
1141 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
1142 ** The implementation might use one or more of the N buffers to hold
1143 ** memory accounting information. The pointer in the first argument must
1144 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite
1145 ** will be undefined.</dd>
1146 **
1147 ** <dt>SQLITE_CONFIG_HEAP</dt>
1148 ** <dd>This option specifies a static memory buffer that SQLite will use
1149 ** for all of its dynamic memory allocation needs beyond those provided
1150 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
1151 ** There are three arguments: An 8-byte aligned pointer to the memory,
1152 ** the number of bytes in the memory buffer, and the minimum allocation size.
1153 ** If the first pointer (the memory pointer) is NULL, then SQLite reverts
1154 ** to using its default memory allocator (the system malloc() implementation),
1155 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. If the
1156 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
1157 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
1158 ** allocator is engaged to handle all of SQLites memory allocation needs.
1159 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1160 ** boundary or subsequent behavior of SQLite will be undefined.</dd>
1161 **
1162 ** <dt>SQLITE_CONFIG_MUTEX</dt>
1163 ** <dd>This option takes a single argument which is a pointer to an
1164 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies
1165 ** alternative low-level mutex routines to be used in place
1166 ** the mutex routines built into SQLite.</dd>
1167 **
1168 ** <dt>SQLITE_CONFIG_GETMUTEX</dt>
1169 ** <dd>This option takes a single argument which is a pointer to an
1170 ** instance of the [sqlite3_mutex_methods] structure. The
1171 ** [sqlite3_mutex_methods]
1172 ** structure is filled with the currently defined mutex routines.
1173 ** This option can be used to overload the default mutex allocation
1174 ** routines with a wrapper used to track mutex usage for performance
1175 ** profiling or testing, for example.</dd>
1176 **
1177 ** <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1178 ** <dd>This option takes two arguments that determine the default
1179 ** memory allocation lookaside optimization. The first argument is the
1180 ** size of each lookaside buffer slot and the second is the number of
1181 ** slots allocated to each database connection. This option sets the
1182 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1183 ** verb to [sqlite3_db_config()] can be used to change the lookaside
1184 ** configuration on individual connections.</dd>
1185 **
1186 ** <dt>SQLITE_CONFIG_PCACHE</dt>
1187 ** <dd>This option takes a single argument which is a pointer to
1188 ** an [sqlite3_pcache_methods] object. This object specifies the interface
1189 ** to a custom page cache implementation. SQLite makes a copy of the
1190 ** object and uses it for page cache memory allocations.</dd>
1191 **
1192 ** <dt>SQLITE_CONFIG_GETPCACHE</dt>
1193 ** <dd>This option takes a single argument which is a pointer to an
1194 ** [sqlite3_pcache_methods] object. SQLite copies of the current
1195 ** page cache implementation into that object.</dd>
1196 **
1197 ** </dl>
1198 */
1199 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1200 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1201 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1202 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1203 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1204 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */
1205 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1206 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1207 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1208 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1209 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1210 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1211 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1212 #define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */
1213 #define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */
1214
1215 /*
1216 ** CAPI3REF: Configuration Options {H10170} <S20000>
1217 ** EXPERIMENTAL
1218 **
1219 ** These constants are the available integer configuration options that
1220 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1221 **
1222 ** New configuration options may be added in future releases of SQLite.
1223 ** Existing configuration options might be discontinued. Applications
1224 ** should check the return code from [sqlite3_db_config()] to make sure that
1225 ** the call worked. The [sqlite3_db_config()] interface will return a
1226 ** non-zero [error code] if a discontinued or unsupported configuration option
1227 ** is invoked.
1228 **
1229 ** <dl>
1230 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1231 ** <dd>This option takes three additional arguments that determine the
1232 ** [lookaside memory allocator] configuration for the [database connection].
1233 ** The first argument (the third parameter to [sqlite3_db_config()] is a
1234 ** pointer to an memory buffer to use for lookaside memory.
1235 ** The first argument may be NULL in which case SQLite will allocate the
1236 ** lookaside buffer itself using [sqlite3_malloc()]. The second argument is the
1237 ** size of each lookaside buffer slot and the third argument is the number of
1238 ** slots. The size of the buffer in the first argument must be greater than
1239 ** or equal to the product of the second and third arguments. The buffer
1240 ** must be aligned to an 8-byte boundary. If the second argument is not
1241 ** a multiple of 8, it is internally rounded down to the next smaller
1242 ** multiple of 8. See also: [SQLITE_CONFIG_LOOKASIDE]</dd>
1243 **
1244 ** </dl>
1245 */
1246 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
1247
1248
1249 /*
1250 ** CAPI3REF: Enable Or Disable Extended Result Codes {H12200} <S10700>
1251 **
1252 ** The sqlite3_extended_result_codes() routine enables or disables the
1253 ** [extended result codes] feature of SQLite. The extended result
1254 ** codes are disabled by default for historical compatibility considerations.
1255 **
1256 ** Requirements:
1257 ** [H12201] [H12202]
1258 */
1259 int sqlite3_extended_result_codes(sqlite3*, int onoff);
1260
1261 /*
1262 ** CAPI3REF: Last Insert Rowid {H12220} <S10700>
1263 **
1264 ** Each entry in an SQLite table has a unique 64-bit signed
1265 ** integer key called the [ROWID | "rowid"]. The rowid is always available
1266 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1267 ** names are not also used by explicitly declared columns. If
1268 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
1269 ** is another alias for the rowid.
1270 **
1271 ** This routine returns the [rowid] of the most recent
1272 ** successful [INSERT] into the database from the [database connection]
1273 ** in the first argument. If no successful [INSERT]s
1274 ** have ever occurred on that database connection, zero is returned.
1275 **
1276 ** If an [INSERT] occurs within a trigger, then the [rowid] of the inserted
1277 ** row is returned by this routine as long as the trigger is running.
1278 ** But once the trigger terminates, the value returned by this routine
1279 ** reverts to the last value inserted before the trigger fired.
1280 **
1281 ** An [INSERT] that fails due to a constraint violation is not a
1282 ** successful [INSERT] and does not change the value returned by this
1283 ** routine. Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1284 ** and INSERT OR ABORT make no changes to the return value of this
1285 ** routine when their insertion fails. When INSERT OR REPLACE
1286 ** encounters a constraint violation, it does not fail. The
1287 ** INSERT continues to completion after deleting rows that caused
1288 ** the constraint problem so INSERT OR REPLACE will always change
1289 ** the return value of this interface.
1290 **
1291 ** For the purposes of this routine, an [INSERT] is considered to
1292 ** be successful even if it is subsequently rolled back.
1293 **
1294 ** Requirements:
1295 ** [H12221] [H12223]
1296 **
1297 ** If a separate thread performs a new [INSERT] on the same
1298 ** database connection while the [sqlite3_last_insert_rowid()]
1299 ** function is running and thus changes the last insert [rowid],
1300 ** then the value returned by [sqlite3_last_insert_rowid()] is
1301 ** unpredictable and might not equal either the old or the new
1302 ** last insert [rowid].
1303 */
1304 sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
1305
1306 /*
1307 ** CAPI3REF: Count The Number Of Rows Modified {H12240} <S10600>
1308 **
1309 ** This function returns the number of database rows that were changed
1310 ** or inserted or deleted by the most recently completed SQL statement
1311 ** on the [database connection] specified by the first parameter.
1312 ** Only changes that are directly specified by the [INSERT], [UPDATE],
1313 ** or [DELETE] statement are counted. Auxiliary changes caused by
1314 ** triggers are not counted. Use the [sqlite3_total_changes()] function
1315 ** to find the total number of changes including changes caused by triggers.
1316 **
1317 ** Changes to a view that are simulated by an [INSTEAD OF trigger]
1318 ** are not counted. Only real table changes are counted.
1319 **
1320 ** A "row change" is a change to a single row of a single table
1321 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that
1322 ** are changed as side effects of [REPLACE] constraint resolution,
1323 ** rollback, ABORT processing, [DROP TABLE], or by any other
1324 ** mechanisms do not count as direct row changes.
1325 **
1326 ** A "trigger context" is a scope of execution that begins and
1327 ** ends with the script of a [CREATE TRIGGER | trigger].
1328 ** Most SQL statements are
1329 ** evaluated outside of any trigger. This is the "top level"
1330 ** trigger context. If a trigger fires from the top level, a
1331 ** new trigger context is entered for the duration of that one
1332 ** trigger. Subtriggers create subcontexts for their duration.
1333 **
1334 ** Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
1335 ** not create a new trigger context.
1336 **
1337 ** This function returns the number of direct row changes in the
1338 ** most recent INSERT, UPDATE, or DELETE statement within the same
1339 ** trigger context.
1340 **
1341 ** Thus, when called from the top level, this function returns the
1342 ** number of changes in the most recent INSERT, UPDATE, or DELETE
1343 ** that also occurred at the top level. Within the body of a trigger,
1344 ** the sqlite3_changes() interface can be called to find the number of
1345 ** changes in the most recently completed INSERT, UPDATE, or DELETE
1346 ** statement within the body of the same trigger.
1347 ** However, the number returned does not include changes
1348 ** caused by subtriggers since those have their own context.
1349 **
1350 ** See also the [sqlite3_total_changes()] interface and the
1351 ** [count_changes pragma].
1352 **
1353 ** Requirements:
1354 ** [H12241] [H12243]
1355 **
1356 ** If a separate thread makes changes on the same database connection
1357 ** while [sqlite3_changes()] is running then the value returned
1358 ** is unpredictable and not meaningful.
1359 */
1360 int sqlite3_changes(sqlite3*);
1361
1362 /*
1363 ** CAPI3REF: Total Number Of Rows Modified {H12260} <S10600>
1364 **
1365 ** This function returns the number of row changes caused by [INSERT],
1366 ** [UPDATE] or [DELETE] statements since the [database connection] was opened.
1367 ** The count includes all changes from all
1368 ** [CREATE TRIGGER | trigger] contexts. However,
1369 ** the count does not include changes used to implement [REPLACE] constraints,
1370 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The
1371 ** count does not include rows of views that fire an [INSTEAD OF trigger],
1372 ** though if the INSTEAD OF trigger makes changes of its own, those changes
1373 ** are counted.
1374 ** The changes are counted as soon as the statement that makes them is
1375 ** completed (when the statement handle is passed to [sqlite3_reset()] or
1376 ** [sqlite3_finalize()]).
1377 **
1378 ** See also the [sqlite3_changes()] interface and the
1379 ** [count_changes pragma].
1380 **
1381 ** Requirements:
1382 ** [H12261] [H12263]
1383 **
1384 ** If a separate thread makes changes on the same database connection
1385 ** while [sqlite3_total_changes()] is running then the value
1386 ** returned is unpredictable and not meaningful.
1387 */
1388 int sqlite3_total_changes(sqlite3*);
1389
1390 /*
1391 ** CAPI3REF: Interrupt A Long-Running Query {H12270} <S30500>
1392 **
1393 ** This function causes any pending database operation to abort and
1394 ** return at its earliest opportunity. This routine is typically
1395 ** called in response to a user action such as pressing "Cancel"
1396 ** or Ctrl-C where the user wants a long query operation to halt
1397 ** immediately.
1398 **
1399 ** It is safe to call this routine from a thread different from the
1400 ** thread that is currently running the database operation. But it
1401 ** is not safe to call this routine with a [database connection] that
1402 ** is closed or might close before sqlite3_interrupt() returns.
1403 **
1404 ** If an SQL operation is very nearly finished at the time when
1405 ** sqlite3_interrupt() is called, then it might not have an opportunity
1406 ** to be interrupted and might continue to completion.
1407 **
1408 ** An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
1409 ** If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
1410 ** that is inside an explicit transaction, then the entire transaction
1411 ** will be rolled back automatically.
1412 **
1413 ** The sqlite3_interrupt(D) call is in effect until all currently running
1414 ** SQL statements on [database connection] D complete. Any new SQL statements
1415 ** that are started after the sqlite3_interrupt() call and before the
1416 ** running statements reaches zero are interrupted as if they had been
1417 ** running prior to the sqlite3_interrupt() call. New SQL statements
1418 ** that are started after the running statement count reaches zero are
1419 ** not effected by the sqlite3_interrupt().
1420 ** A call to sqlite3_interrupt(D) that occurs when there are no running
1421 ** SQL statements is a no-op and has no effect on SQL statements
1422 ** that are started after the sqlite3_interrupt() call returns.
1423 **
1424 ** Requirements:
1425 ** [H12271] [H12272]
1426 **
1427 ** If the database connection closes while [sqlite3_interrupt()]
1428 ** is running then bad things will likely happen.
1429 */
1430 void sqlite3_interrupt(sqlite3*);
1431
1432 /*
1433 ** CAPI3REF: Determine If An SQL Statement Is Complete {H10510} <S70200>
1434 **
1435 ** These routines are useful during command-line input to determine if the
1436 ** currently entered text seems to form a complete SQL statement or
1437 ** if additional input is needed before sending the text into
1438 ** SQLite for parsing. These routines return 1 if the input string
1439 ** appears to be a complete SQL statement. A statement is judged to be
1440 ** complete if it ends with a semicolon token and is not a prefix of a
1441 ** well-formed CREATE TRIGGER statement. Semicolons that are embedded within
1442 ** string literals or quoted identifier names or comments are not
1443 ** independent tokens (they are part of the token in which they are
1444 ** embedded) and thus do not count as a statement terminator. Whitespace
1445 ** and comments that follow the final semicolon are ignored.
1446 **
1447 ** These routines return 0 if the statement is incomplete. If a
1448 ** memory allocation fails, then SQLITE_NOMEM is returned.
1449 **
1450 ** These routines do not parse the SQL statements thus
1451 ** will not detect syntactically incorrect SQL.
1452 **
1453 ** If SQLite has not been initialized using [sqlite3_initialize()] prior
1454 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
1455 ** automatically by sqlite3_complete16(). If that initialization fails,
1456 ** then the return value from sqlite3_complete16() will be non-zero
1457 ** regardless of whether or not the input SQL is complete.
1458 **
1459 ** Requirements: [H10511] [H10512]
1460 **
1461 ** The input to [sqlite3_complete()] must be a zero-terminated
1462 ** UTF-8 string.
1463 **
1464 ** The input to [sqlite3_complete16()] must be a zero-terminated
1465 ** UTF-16 string in native byte order.
1466 */
1467 int sqlite3_complete(const char *sql);
1468 int sqlite3_complete16(const void *sql);
1469
1470 /*
1471 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors {H12310} <S40400>
1472 **
1473 ** This routine sets a callback function that might be invoked whenever
1474 ** an attempt is made to open a database table that another thread
1475 ** or process has locked.
1476 **
1477 ** If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
1478 ** is returned immediately upon encountering the lock. If the busy callback
1479 ** is not NULL, then the callback will be invoked with two arguments.
1480 **
1481 ** The first argument to the handler is a copy of the void* pointer which
1482 ** is the third argument to sqlite3_busy_handler(). The second argument to
1483 ** the handler callback is the number of times that the busy handler has
1484 ** been invoked for this locking event. If the
1485 ** busy callback returns 0, then no additional attempts are made to
1486 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
1487 ** If the callback returns non-zero, then another attempt
1488 ** is made to open the database for reading and the cycle repeats.
1489 **
1490 ** The presence of a busy handler does not guarantee that it will be invoked
1491 ** when there is lock contention. If SQLite determines that invoking the busy
1492 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
1493 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
1494 ** Consider a scenario where one process is holding a read lock that
1495 ** it is trying to promote to a reserved lock and
1496 ** a second process is holding a reserved lock that it is trying
1497 ** to promote to an exclusive lock. The first process cannot proceed
1498 ** because it is blocked by the second and the second process cannot
1499 ** proceed because it is blocked by the first. If both processes
1500 ** invoke the busy handlers, neither will make any progress. Therefore,
1501 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
1502 ** will induce the first process to release its read lock and allow
1503 ** the second process to proceed.
1504 **
1505 ** The default busy callback is NULL.
1506 **
1507 ** The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
1508 ** when SQLite is in the middle of a large transaction where all the
1509 ** changes will not fit into the in-memory cache. SQLite will
1510 ** already hold a RESERVED lock on the database file, but it needs
1511 ** to promote this lock to EXCLUSIVE so that it can spill cache
1512 ** pages into the database file without harm to concurrent
1513 ** readers. If it is unable to promote the lock, then the in-memory
1514 ** cache will be left in an inconsistent state and so the error
1515 ** code is promoted from the relatively benign [SQLITE_BUSY] to
1516 ** the more severe [SQLITE_IOERR_BLOCKED]. This error code promotion
1517 ** forces an automatic rollback of the changes. See the
1518 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
1519 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
1520 ** this is important.
1521 **
1522 ** There can only be a single busy handler defined for each
1523 ** [database connection]. Setting a new busy handler clears any
1524 ** previously set handler. Note that calling [sqlite3_busy_timeout()]
1525 ** will also set or clear the busy handler.
1526 **
1527 ** The busy callback should not take any actions which modify the
1528 ** database connection that invoked the busy handler. Any such actions
1529 ** result in undefined behavior.
1530 **
1531 ** Requirements:
1532 ** [H12311] [H12312] [H12314] [H12316] [H12318]
1533 **
1534 ** A busy handler must not close the database connection
1535 ** or [prepared statement] that invoked the busy handler.
1536 */
1537 int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
1538
1539 /*
1540 ** CAPI3REF: Set A Busy Timeout {H12340} <S40410>
1541 **
1542 ** This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
1543 ** for a specified amount of time when a table is locked. The handler
1544 ** will sleep multiple times until at least "ms" milliseconds of sleeping
1545 ** have accumulated. {H12343} After "ms" milliseconds of sleeping,
1546 ** the handler returns 0 which causes [sqlite3_step()] to return
1547 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
1548 **
1549 ** Calling this routine with an argument less than or equal to zero
1550 ** turns off all busy handlers.
1551 **
1552 ** There can only be a single busy handler for a particular
1553 ** [database connection] any any given moment. If another busy handler
1554 ** was defined (using [sqlite3_busy_handler()]) prior to calling
1555 ** this routine, that other busy handler is cleared.
1556 **
1557 ** Requirements:
1558 ** [H12341] [H12343] [H12344]
1559 */
1560 int sqlite3_busy_timeout(sqlite3*, int ms);
1561
1562 /*
1563 ** CAPI3REF: Convenience Routines For Running Queries {H12370} <S10000>
1564 **
1565 ** Definition: A <b>result table</b> is memory data structure created by the
1566 ** [sqlite3_get_table()] interface. A result table records the
1567 ** complete query results from one or more queries.
1568 **
1569 ** The table conceptually has a number of rows and columns. But
1570 ** these numbers are not part of the result table itself. These
1571 ** numbers are obtained separately. Let N be the number of rows
1572 ** and M be the number of columns.
1573 **
1574 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
1575 ** There are (N+1)*M elements in the array. The first M pointers point
1576 ** to zero-terminated strings that contain the names of the columns.
1577 ** The remaining entries all point to query results. NULL values result
1578 ** in NULL pointers. All other values are in their UTF-8 zero-terminated
1579 ** string representation as returned by [sqlite3_column_text()].
1580 **
1581 ** A result table might consist of one or more memory allocations.
1582 ** It is not safe to pass a result table directly to [sqlite3_free()].
1583 ** A result table should be deallocated using [sqlite3_free_table()].
1584 **
1585 ** As an example of the result table format, suppose a query result
1586 ** is as follows:
1587 **
1588 ** <blockquote><pre>
1589 ** Name | Age
1590 ** -----------------------
1591 ** Alice | 43
1592 ** Bob | 28
1593 ** Cindy | 21
1594 ** </pre></blockquote>
1595 **
1596 ** There are two column (M==2) and three rows (N==3). Thus the
1597 ** result table has 8 entries. Suppose the result table is stored
1598 ** in an array names azResult. Then azResult holds this content:
1599 **
1600 ** <blockquote><pre>
1601 ** azResult&#91;0] = "Name";
1602 ** azResult&#91;1] = "Age";
1603 ** azResult&#91;2] = "Alice";
1604 ** azResult&#91;3] = "43";
1605 ** azResult&#91;4] = "Bob";
1606 ** azResult&#91;5] = "28";
1607 ** azResult&#91;6] = "Cindy";
1608 ** azResult&#91;7] = "21";
1609 ** </pre></blockquote>
1610 **
1611 ** The sqlite3_get_table() function evaluates one or more
1612 ** semicolon-separated SQL statements in the zero-terminated UTF-8
1613 ** string of its 2nd parameter. It returns a result table to the
1614 ** pointer given in its 3rd parameter.
1615 **
1616 ** After the calling function has finished using the result, it should
1617 ** pass the pointer to the result table to sqlite3_free_table() in order to
1618 ** release the memory that was malloced. Because of the way the
1619 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
1620 ** function must not try to call [sqlite3_free()] directly. Only
1621 ** [sqlite3_free_table()] is able to release the memory properly and safely.
1622 **
1623 ** The sqlite3_get_table() interface is implemented as a wrapper around
1624 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
1625 ** to any internal data structures of SQLite. It uses only the public
1626 ** interface defined here. As a consequence, errors that occur in the
1627 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
1628 ** reflected in subsequent calls to [sqlite3_errcode()] or [sqlite3_errmsg()].
1629 **
1630 ** Requirements:
1631 ** [H12371] [H12373] [H12374] [H12376] [H12379] [H12382]
1632 */
1633 int sqlite3_get_table(
1634 sqlite3 *db, /* An open database */
1635 const char *zSql, /* SQL to be evaluated */
1636 char ***pazResult, /* Results of the query */
1637 int *pnRow, /* Number of result rows written here */
1638 int *pnColumn, /* Number of result columns written here */
1639 char **pzErrmsg /* Error msg written here */
1640 );
1641 void sqlite3_free_table(char **result);
1642
1643 /*
1644 ** CAPI3REF: Formatted String Printing Functions {H17400} <S70000><S20000>
1645 **
1646 ** These routines are work-alikes of the "printf()" family of functions
1647 ** from the standard C library.
1648 **
1649 ** The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
1650 ** results into memory obtained from [sqlite3_malloc()].
1651 ** The strings returned by these two routines should be
1652 ** released by [sqlite3_free()]. Both routines return a
1653 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
1654 ** memory to hold the resulting string.
1655 **
1656 ** In sqlite3_snprintf() routine is similar to "snprintf()" from
1657 ** the standard C library. The result is written into the
1658 ** buffer supplied as the second parameter whose size is given by
1659 ** the first parameter. Note that the order of the
1660 ** first two parameters is reversed from snprintf(). This is an
1661 ** historical accident that cannot be fixed without breaking
1662 ** backwards compatibility. Note also that sqlite3_snprintf()
1663 ** returns a pointer to its buffer instead of the number of
1664 ** characters actually written into the buffer. We admit that
1665 ** the number of characters written would be a more useful return
1666 ** value but we cannot change the implementation of sqlite3_snprintf()
1667 ** now without breaking compatibility.
1668 **
1669 ** As long as the buffer size is greater than zero, sqlite3_snprintf()
1670 ** guarantees that the buffer is always zero-terminated. The first
1671 ** parameter "n" is the total size of the buffer, including space for
1672 ** the zero terminator. So the longest string that can be completely
1673 ** written will be n-1 characters.
1674 **
1675 ** These routines all implement some additional formatting
1676 ** options that are useful for constructing SQL statements.
1677 ** All of the usual printf() formatting options apply. In addition, there
1678 ** is are "%q", "%Q", and "%z" options.
1679 **
1680 ** The %q option works like %s in that it substitutes a null-terminated
1681 ** string from the argument list. But %q also doubles every '\'' character.
1682 ** %q is designed for use inside a string literal. By doubling each '\''
1683 ** character it escapes that character and allows it to be inserted into
1684 ** the string.
1685 **
1686 ** For example, assume the string variable zText contains text as follows:
1687 **
1688 ** <blockquote><pre>
1689 ** char *zText = "It's a happy day!";
1690 ** </pre></blockquote>
1691 **
1692 ** One can use this text in an SQL statement as follows:
1693 **
1694 ** <blockquote><pre>
1695 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
1696 ** sqlite3_exec(db, zSQL, 0, 0, 0);
1697 ** sqlite3_free(zSQL);
1698 ** </pre></blockquote>
1699 **
1700 ** Because the %q format string is used, the '\'' character in zText
1701 ** is escaped and the SQL generated is as follows:
1702 **
1703 ** <blockquote><pre>
1704 ** INSERT INTO table1 VALUES('It''s a happy day!')
1705 ** </pre></blockquote>
1706 **
1707 ** This is correct. Had we used %s instead of %q, the generated SQL
1708 ** would have looked like this:
1709 **
1710 ** <blockquote><pre>
1711 ** INSERT INTO table1 VALUES('It's a happy day!');
1712 ** </pre></blockquote>
1713 **
1714 ** This second example is an SQL syntax error. As a general rule you should
1715 ** always use %q instead of %s when inserting text into a string literal.
1716 **
1717 ** The %Q option works like %q except it also adds single quotes around
1718 ** the outside of the total string. Additionally, if the parameter in the
1719 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
1720 ** single quotes) in place of the %Q option. So, for example, one could say:
1721 **
1722 ** <blockquote><pre>
1723 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
1724 ** sqlite3_exec(db, zSQL, 0, 0, 0);
1725 ** sqlite3_free(zSQL);
1726 ** </pre></blockquote>
1727 **
1728 ** The code above will render a correct SQL statement in the zSQL
1729 ** variable even if the zText variable is a NULL pointer.
1730 **
1731 ** The "%z" formatting option works exactly like "%s" with the
1732 ** addition that after the string has been read and copied into
1733 ** the result, [sqlite3_free()] is called on the input string. {END}
1734 **
1735 ** Requirements:
1736 ** [H17403] [H17406] [H17407]
1737 */
1738 char *sqlite3_mprintf(const char*,...);
1739 char *sqlite3_vmprintf(const char*, va_list);
1740 char *sqlite3_snprintf(int,char*,const char*, ...);
1741
1742 /*
1743 ** CAPI3REF: Memory Allocation Subsystem {H17300} <S20000>
1744 **
1745 ** The SQLite core uses these three routines for all of its own
1746 ** internal memory allocation needs. "Core" in the previous sentence
1747 ** does not include operating-system specific VFS implementation. The
1748 ** Windows VFS uses native malloc() and free() for some operations.
1749 **
1750 ** The sqlite3_malloc() routine returns a pointer to a block
1751 ** of memory at least N bytes in length, where N is the parameter.
1752 ** If sqlite3_malloc() is unable to obtain sufficient free
1753 ** memory, it returns a NULL pointer. If the parameter N to
1754 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
1755 ** a NULL pointer.
1756 **
1757 ** Calling sqlite3_free() with a pointer previously returned
1758 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
1759 ** that it might be reused. The sqlite3_free() routine is
1760 ** a no-op if is called with a NULL pointer. Passing a NULL pointer
1761 ** to sqlite3_free() is harmless. After being freed, memory
1762 ** should neither be read nor written. Even reading previously freed
1763 ** memory might result in a segmentation fault or other severe error.
1764 ** Memory corruption, a segmentation fault, or other severe error
1765 ** might result if sqlite3_free() is called with a non-NULL pointer that
1766 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
1767 **
1768 ** The sqlite3_realloc() interface attempts to resize a
1769 ** prior memory allocation to be at least N bytes, where N is the
1770 ** second parameter. The memory allocation to be resized is the first
1771 ** parameter. If the first parameter to sqlite3_realloc()
1772 ** is a NULL pointer then its behavior is identical to calling
1773 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
1774 ** If the second parameter to sqlite3_realloc() is zero or
1775 ** negative then the behavior is exactly the same as calling
1776 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
1777 ** sqlite3_realloc() returns a pointer to a memory allocation
1778 ** of at least N bytes in size or NULL if sufficient memory is unavailable.
1779 ** If M is the size of the prior allocation, then min(N,M) bytes
1780 ** of the prior allocation are copied into the beginning of buffer returned
1781 ** by sqlite3_realloc() and the prior allocation is freed.
1782 ** If sqlite3_realloc() returns NULL, then the prior allocation
1783 ** is not freed.
1784 **
1785 ** The memory returned by sqlite3_malloc() and sqlite3_realloc()
1786 ** is always aligned to at least an 8 byte boundary. {END}
1787 **
1788 ** The default implementation of the memory allocation subsystem uses
1789 ** the malloc(), realloc() and free() provided by the standard C library.
1790 ** {H17382} However, if SQLite is compiled with the
1791 ** SQLITE_MEMORY_SIZE=<i>NNN</i> C preprocessor macro (where <i>NNN</i>
1792 ** is an integer), then SQLite create a static array of at least
1793 ** <i>NNN</i> bytes in size and uses that array for all of its dynamic
1794 ** memory allocation needs. {END} Additional memory allocator options
1795 ** may be added in future releases.
1796 **
1797 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
1798 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
1799 ** implementation of these routines to be omitted. That capability
1800 ** is no longer provided. Only built-in memory allocators can be used.
1801 **
1802 ** The Windows OS interface layer calls
1803 ** the system malloc() and free() directly when converting
1804 ** filenames between the UTF-8 encoding used by SQLite
1805 ** and whatever filename encoding is used by the particular Windows
1806 ** installation. Memory allocation errors are detected, but
1807 ** they are reported back as [SQLITE_CANTOPEN] or
1808 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
1809 **
1810 ** Requirements:
1811 ** [H17303] [H17304] [H17305] [H17306] [H17310] [H17312] [H17315] [H17318]
1812 ** [H17321] [H17322] [H17323]
1813 **
1814 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
1815 ** must be either NULL or else pointers obtained from a prior
1816 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
1817 ** not yet been released.
1818 **
1819 ** The application must not read or write any part of
1820 ** a block of memory after it has been released using
1821 ** [sqlite3_free()] or [sqlite3_realloc()].
1822 */
1823 void *sqlite3_malloc(int);
1824 void *sqlite3_realloc(void*, int);
1825 void sqlite3_free(void*);
1826
1827 /*
1828 ** CAPI3REF: Memory Allocator Statistics {H17370} <S30210>
1829 **
1830 ** SQLite provides these two interfaces for reporting on the status
1831 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
1832 ** routines, which form the built-in memory allocation subsystem.
1833 **
1834 ** Requirements:
1835 ** [H17371] [H17373] [H17374] [H17375]
1836 */
1837 sqlite3_int64 sqlite3_memory_used(void);
1838 sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
1839
1840 /*
1841 ** CAPI3REF: Pseudo-Random Number Generator {H17390} <S20000>
1842 **
1843 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
1844 ** select random [ROWID | ROWIDs] when inserting new records into a table that
1845 ** already uses the largest possible [ROWID]. The PRNG is also used for
1846 ** the build-in random() and randomblob() SQL functions. This interface allows
1847 ** applications to access the same PRNG for other purposes.
1848 **
1849 ** A call to this routine stores N bytes of randomness into buffer P.
1850 **
1851 ** The first time this routine is invoked (either internally or by
1852 ** the application) the PRNG is seeded using randomness obtained
1853 ** from the xRandomness method of the default [sqlite3_vfs] object.
1854 ** On all subsequent invocations, the pseudo-randomness is generated
1855 ** internally and without recourse to the [sqlite3_vfs] xRandomness
1856 ** method.
1857 **
1858 ** Requirements:
1859 ** [H17392]
1860 */
1861 void sqlite3_randomness(int N, void *P);
1862
1863 /*
1864 ** CAPI3REF: Compile-Time Authorization Callbacks {H12500} <S70100>
1865 **
1866 ** This routine registers a authorizer callback with a particular
1867 ** [database connection], supplied in the first argument.
1868 ** The authorizer callback is invoked as SQL statements are being compiled
1869 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
1870 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. At various
1871 ** points during the compilation process, as logic is being created
1872 ** to perform various actions, the authorizer callback is invoked to
1873 ** see if those actions are allowed. The authorizer callback should
1874 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
1875 ** specific action but allow the SQL statement to continue to be
1876 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
1877 ** rejected with an error. If the authorizer callback returns
1878 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
1879 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
1880 ** the authorizer will fail with an error message.
1881 **
1882 ** When the callback returns [SQLITE_OK], that means the operation
1883 ** requested is ok. When the callback returns [SQLITE_DENY], the
1884 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
1885 ** authorizer will fail with an error message explaining that
1886 ** access is denied.
1887 **
1888 ** The first parameter to the authorizer callback is a copy of the third
1889 ** parameter to the sqlite3_set_authorizer() interface. The second parameter
1890 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
1891 ** the particular action to be authorized. The third through sixth parameters
1892 ** to the callback are zero-terminated strings that contain additional
1893 ** details about the action to be authorized.
1894 **
1895 ** If the action code is [SQLITE_READ]
1896 ** and the callback returns [SQLITE_IGNORE] then the
1897 ** [prepared statement] statement is constructed to substitute
1898 ** a NULL value in place of the table column that would have
1899 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
1900 ** return can be used to deny an untrusted user access to individual
1901 ** columns of a table.
1902 ** If the action code is [SQLITE_DELETE] and the callback returns
1903 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
1904 ** [truncate optimization] is disabled and all rows are deleted individually.
1905 **
1906 ** An authorizer is used when [sqlite3_prepare | preparing]
1907 ** SQL statements from an untrusted source, to ensure that the SQL statements
1908 ** do not try to access data they are not allowed to see, or that they do not
1909 ** try to execute malicious statements that damage the database. For
1910 ** example, an application may allow a user to enter arbitrary
1911 ** SQL queries for evaluation by a database. But the application does
1912 ** not want the user to be able to make arbitrary changes to the
1913 ** database. An authorizer could then be put in place while the
1914 ** user-entered SQL is being [sqlite3_prepare | prepared] that
1915 ** disallows everything except [SELECT] statements.
1916 **
1917 ** Applications that need to process SQL from untrusted sources
1918 ** might also consider lowering resource limits using [sqlite3_limit()]
1919 ** and limiting database size using the [max_page_count] [PRAGMA]
1920 ** in addition to using an authorizer.
1921 **
1922 ** Only a single authorizer can be in place on a database connection
1923 ** at a time. Each call to sqlite3_set_authorizer overrides the
1924 ** previous call. Disable the authorizer by installing a NULL callback.
1925 ** The authorizer is disabled by default.
1926 **
1927 ** The authorizer callback must not do anything that will modify
1928 ** the database connection that invoked the authorizer callback.
1929 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
1930 ** database connections for the meaning of "modify" in this paragraph.
1931 **
1932 ** When [sqlite3_prepare_v2()] is used to prepare a statement, the
1933 ** statement might be re-prepared during [sqlite3_step()] due to a
1934 ** schema change. Hence, the application should ensure that the
1935 ** correct authorizer callback remains in place during the [sqlite3_step()].
1936 **
1937 ** Note that the authorizer callback is invoked only during
1938 ** [sqlite3_prepare()] or its variants. Authorization is not
1939 ** performed during statement evaluation in [sqlite3_step()], unless
1940 ** as stated in the previous paragraph, sqlite3_step() invokes
1941 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
1942 **
1943 ** Requirements:
1944 ** [H12501] [H12502] [H12503] [H12504] [H12505] [H12506] [H12507] [H12510]
1945 ** [H12511] [H12512] [H12520] [H12521] [H12522]
1946 */
1947 int sqlite3_set_authorizer(
1948 sqlite3*,
1949 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
1950 void *pUserData
1951 );
1952
1953 /*
1954 ** CAPI3REF: Authorizer Return Codes {H12590} <H12500>
1955 **
1956 ** The [sqlite3_set_authorizer | authorizer callback function] must
1957 ** return either [SQLITE_OK] or one of these two constants in order
1958 ** to signal SQLite whether or not the action is permitted. See the
1959 ** [sqlite3_set_authorizer | authorizer documentation] for additional
1960 ** information.
1961 */
1962 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */
1963 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
1964
1965 /*
1966 ** CAPI3REF: Authorizer Action Codes {H12550} <H12500>
1967 **
1968 ** The [sqlite3_set_authorizer()] interface registers a callback function
1969 ** that is invoked to authorize certain SQL statement actions. The
1970 ** second parameter to the callback is an integer code that specifies
1971 ** what action is being authorized. These are the integer action codes that
1972 ** the authorizer callback may be passed.
1973 **
1974 ** These action code values signify what kind of operation is to be
1975 ** authorized. The 3rd and 4th parameters to the authorization
1976 ** callback function will be parameters or NULL depending on which of these
1977 ** codes is used as the second parameter. The 5th parameter to the
1978 ** authorizer callback is the name of the database ("main", "temp",
1979 ** etc.) if applicable. The 6th parameter to the authorizer callback
1980 ** is the name of the inner-most trigger or view that is responsible for
1981 ** the access attempt or NULL if this access attempt is directly from
1982 ** top-level SQL code.
1983 **
1984 ** Requirements:
1985 ** [H12551] [H12552] [H12553] [H12554]
1986 */
1987 /******************************************* 3rd ************ 4th ***********/
1988 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
1989 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
1990 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
1991 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
1992 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
1993 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
1994 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
1995 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */
1996 #define SQLITE_DELETE 9 /* Table Name NULL */
1997 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
1998 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */
1999 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2000 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2001 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2002 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2003 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2004 #define SQLITE_DROP_VIEW 17 /* View Name NULL */
2005 #define SQLITE_INSERT 18 /* Table Name NULL */
2006 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2007 #define SQLITE_READ 20 /* Table Name Column Name */
2008 #define SQLITE_SELECT 21 /* NULL NULL */
2009 #define SQLITE_TRANSACTION 22 /* Operation NULL */
2010 #define SQLITE_UPDATE 23 /* Table Name Column Name */
2011 #define SQLITE_ATTACH 24 /* Filename NULL */
2012 #define SQLITE_DETACH 25 /* Database Name NULL */
2013 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2014 #define SQLITE_REINDEX 27 /* Index Name NULL */
2015 #define SQLITE_ANALYZE 28 /* Table Name NULL */
2016 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2017 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2018 #define SQLITE_FUNCTION 31 /* NULL Function Name */
2019 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2020 #define SQLITE_COPY 0 /* No longer used */
2021
2022 /*
2023 ** CAPI3REF: Tracing And Profiling Functions {H12280} <S60400>
2024 ** EXPERIMENTAL
2025 **
2026 ** These routines register callback functions that can be used for
2027 ** tracing and profiling the execution of SQL statements.
2028 **
2029 ** The callback function registered by sqlite3_trace() is invoked at
2030 ** various times when an SQL statement is being run by [sqlite3_step()].
2031 ** The callback returns a UTF-8 rendering of the SQL statement text
2032 ** as the statement first begins executing. Additional callbacks occur
2033 ** as each triggered subprogram is entered. The callbacks for triggers
2034 ** contain a UTF-8 SQL comment that identifies the trigger.
2035 **
2036 ** The callback function registered by sqlite3_profile() is invoked
2037 ** as each SQL statement finishes. The profile callback contains
2038 ** the original statement text and an estimate of wall-clock time
2039 ** of how long that statement took to run.
2040 **
2041 ** Requirements:
2042 ** [H12281] [H12282] [H12283] [H12284] [H12285] [H12287] [H12288] [H12289]
2043 ** [H12290]
2044 */
2045 SQLITE_EXPERIMENTAL void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char *), void*);
2046 SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
2047 void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2048
2049 /*
2050 ** CAPI3REF: Query Progress Callbacks {H12910} <S60400>
2051 **
2052 ** This routine configures a callback function - the
2053 ** progress callback - that is invoked periodically during long
2054 ** running calls to [sqlite3_exec()], [sqlite3_step()] and
2055 ** [sqlite3_get_table()]. An example use for this
2056 ** interface is to keep a GUI updated during a large query.
2057 **
2058 ** If the progress callback returns non-zero, the operation is
2059 ** interrupted. This feature can be used to implement a
2060 ** "Cancel" button on a GUI progress dialog box.
2061 **
2062 ** The progress handler must not do anything that will modify
2063 ** the database connection that invoked the progress handler.
2064 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2065 ** database connections for the meaning of "modify" in this paragraph.
2066 **
2067 ** Requirements:
2068 ** [H12911] [H12912] [H12913] [H12914] [H12915] [H12916] [H12917] [H12918]
2069 **
2070 */
2071 void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2072
2073 /*
2074 ** CAPI3REF: Opening A New Database Connection {H12700} <S40200>
2075 **
2076 ** These routines open an SQLite database file whose name is given by the
2077 ** filename argument. The filename argument is interpreted as UTF-8 for
2078 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2079 ** order for sqlite3_open16(). A [database connection] handle is usually
2080 ** returned in *ppDb, even if an error occurs. The only exception is that
2081 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2082 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2083 ** object. If the database is opened (and/or created) successfully, then
2084 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned. The
2085 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2086 ** an English language description of the error.
2087 **
2088 ** The default encoding for the database will be UTF-8 if
2089 ** sqlite3_open() or sqlite3_open_v2() is called and
2090 ** UTF-16 in the native byte order if sqlite3_open16() is used.
2091 **
2092 ** Whether or not an error occurs when it is opened, resources
2093 ** associated with the [database connection] handle should be released by
2094 ** passing it to [sqlite3_close()] when it is no longer required.
2095 **
2096 ** The sqlite3_open_v2() interface works like sqlite3_open()
2097 ** except that it accepts two additional parameters for additional control
2098 ** over the new database connection. The flags parameter can take one of
2099 ** the following three values, optionally combined with the
2100 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2101 ** and/or [SQLITE_OPEN_PRIVATECACHE] flags:
2102 **
2103 ** <dl>
2104 ** <dt>[SQLITE_OPEN_READONLY]</dt>
2105 ** <dd>The database is opened in read-only mode. If the database does not
2106 ** already exist, an error is returned.</dd>
2107 **
2108 ** <dt>[SQLITE_OPEN_READWRITE]</dt>
2109 ** <dd>The database is opened for reading and writing if possible, or reading
2110 ** only if the file is write protected by the operating system. In either
2111 ** case the database must already exist, otherwise an error is returned.</dd>
2112 **
2113 ** <dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2114 ** <dd>The database is opened for reading and writing, and is creates it if
2115 ** it does not already exist. This is the behavior that is always used for
2116 ** sqlite3_open() and sqlite3_open16().</dd>
2117 ** </dl>
2118 **
2119 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
2120 ** combinations shown above or one of the combinations shown above combined
2121 ** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX],
2122 ** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_SHAREDCACHE] flags,
2123 ** then the behavior is undefined.
2124 **
2125 ** If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2126 ** opens in the multi-thread [threading mode] as long as the single-thread
2127 ** mode has not been set at compile-time or start-time. If the
2128 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2129 ** in the serialized [threading mode] unless single-thread was
2130 ** previously selected at compile-time or start-time.
2131 ** The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2132 ** eligible to use [shared cache mode], regardless of whether or not shared
2133 ** cache is enabled using [sqlite3_enable_shared_cache()]. The
2134 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2135 ** participate in [shared cache mode] even if it is enabled.
2136 **
2137 ** If the filename is ":memory:", then a private, temporary in-memory database
2138 ** is created for the connection. This in-memory database will vanish when
2139 ** the database connection is closed. Future versions of SQLite might
2140 ** make use of additional special filenames that begin with the ":" character.
2141 ** It is recommended that when a database filename actually does begin with
2142 ** a ":" character you should prefix the filename with a pathname such as
2143 ** "./" to avoid ambiguity.
2144 **
2145 ** If the filename is an empty string, then a private, temporary
2146 ** on-disk database will be created. This private database will be
2147 ** automatically deleted as soon as the database connection is closed.
2148 **
2149 ** The fourth parameter to sqlite3_open_v2() is the name of the
2150 ** [sqlite3_vfs] object that defines the operating system interface that
2151 ** the new database connection should use. If the fourth parameter is
2152 ** a NULL pointer then the default [sqlite3_vfs] object is used.
2153 **
2154 ** <b>Note to Windows users:</b> The encoding used for the filename argument
2155 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2156 ** codepage is currently defined. Filenames containing international
2157 ** characters must be converted to UTF-8 prior to passing them into
2158 ** sqlite3_open() or sqlite3_open_v2().
2159 **
2160 ** Requirements:
2161 ** [H12701] [H12702] [H12703] [H12704] [H12706] [H12707] [H12709] [H12711]
2162 ** [H12712] [H12713] [H12714] [H12717] [H12719] [H12721] [H12723]
2163 */
2164 int sqlite3_open(
2165 const char *filename, /* Database filename (UTF-8) */
2166 sqlite3 **ppDb /* OUT: SQLite db handle */
2167 );
2168 int sqlite3_open16(
2169 const void *filename, /* Database filename (UTF-16) */
2170 sqlite3 **ppDb /* OUT: SQLite db handle */
2171 );
2172 int sqlite3_open_v2(
2173 const char *filename, /* Database filename (UTF-8) */
2174 sqlite3 **ppDb, /* OUT: SQLite db handle */
2175 int flags, /* Flags */
2176 const char *zVfs /* Name of VFS module to use */
2177 );
2178
2179 /*
2180 ** CAPI3REF: Error Codes And Messages {H12800} <S60200>
2181 **
2182 ** The sqlite3_errcode() interface returns the numeric [result code] or
2183 ** [extended result code] for the most recent failed sqlite3_* API call
2184 ** associated with a [database connection]. If a prior API call failed
2185 ** but the most recent API call succeeded, the return value from
2186 ** sqlite3_errcode() is undefined. The sqlite3_extended_errcode()
2187 ** interface is the same except that it always returns the
2188 ** [extended result code] even when extended result codes are
2189 ** disabled.
2190 **
2191 ** The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
2192 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
2193 ** Memory to hold the error message string is managed internally.
2194 ** The application does not need to worry about freeing the result.
2195 ** However, the error string might be overwritten or deallocated by
2196 ** subsequent calls to other SQLite interface functions.
2197 **
2198 ** When the serialized [threading mode] is in use, it might be the
2199 ** case that a second error occurs on a separate thread in between
2200 ** the time of the first error and the call to these interfaces.
2201 ** When that happens, the second error will be reported since these
2202 ** interfaces always report the most recent result. To avoid
2203 ** this, each thread can obtain exclusive use of the [database connection] D
2204 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
2205 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
2206 ** all calls to the interfaces listed here are completed.
2207 **
2208 ** If an interface fails with SQLITE_MISUSE, that means the interface
2209 ** was invoked incorrectly by the application. In that case, the
2210 ** error code and message may or may not be set.
2211 **
2212 ** Requirements:
2213 ** [H12801] [H12802] [H12803] [H12807] [H12808] [H12809]
2214 */
2215 int sqlite3_errcode(sqlite3 *db);
2216 int sqlite3_extended_errcode(sqlite3 *db);
2217 const char *sqlite3_errmsg(sqlite3*);
2218 const void *sqlite3_errmsg16(sqlite3*);
2219
2220 /*
2221 ** CAPI3REF: SQL Statement Object {H13000} <H13010>
2222 ** KEYWORDS: {prepared statement} {prepared statements}
2223 **
2224 ** An instance of this object represents a single SQL statement.
2225 ** This object is variously known as a "prepared statement" or a
2226 ** "compiled SQL statement" or simply as a "statement".
2227 **
2228 ** The life of a statement object goes something like this:
2229 **
2230 ** <ol>
2231 ** <li> Create the object using [sqlite3_prepare_v2()] or a related
2232 ** function.
2233 ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
2234 ** interfaces.
2235 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
2236 ** <li> Reset the statement using [sqlite3_reset()] then go back
2237 ** to step 2. Do this zero or more times.
2238 ** <li> Destroy the object using [sqlite3_finalize()].
2239 ** </ol>
2240 **
2241 ** Refer to documentation on individual methods above for additional
2242 ** information.
2243 */
2244 typedef struct sqlite3_stmt sqlite3_stmt;
2245
2246 /*
2247 ** CAPI3REF: Run-time Limits {H12760} <S20600>
2248 **
2249 ** This interface allows the size of various constructs to be limited
2250 ** on a connection by connection basis. The first parameter is the
2251 ** [database connection] whose limit is to be set or queried. The
2252 ** second parameter is one of the [limit categories] that define a
2253 ** class of constructs to be size limited. The third parameter is the
2254 ** new limit for that construct. The function returns the old limit.
2255 **
2256 ** If the new limit is a negative number, the limit is unchanged.
2257 ** For the limit category of SQLITE_LIMIT_XYZ there is a
2258 ** [limits | hard upper bound]
2259 ** set by a compile-time C preprocessor macro named
2260 ** [limits | SQLITE_MAX_XYZ].
2261 ** (The "_LIMIT_" in the name is changed to "_MAX_".)
2262 ** Attempts to increase a limit above its hard upper bound are
2263 ** silently truncated to the hard upper limit.
2264 **
2265 ** Run time limits are intended for use in applications that manage
2266 ** both their own internal database and also databases that are controlled
2267 ** by untrusted external sources. An example application might be a
2268 ** web browser that has its own databases for storing history and
2269 ** separate databases controlled by JavaScript applications downloaded
2270 ** off the Internet. The internal databases can be given the
2271 ** large, default limits. Databases managed by external sources can
2272 ** be given much smaller limits designed to prevent a denial of service
2273 ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
2274 ** interface to further control untrusted SQL. The size of the database
2275 ** created by an untrusted script can be contained using the
2276 ** [max_page_count] [PRAGMA].
2277 **
2278 ** New run-time limit categories may be added in future releases.
2279 **
2280 ** Requirements:
2281 ** [H12762] [H12766] [H12769]
2282 */
2283 int sqlite3_limit(sqlite3*, int id, int newVal);
2284
2285 /*
2286 ** CAPI3REF: Run-Time Limit Categories {H12790} <H12760>
2287 ** KEYWORDS: {limit category} {limit categories}
2288 **
2289 ** These constants define various performance limits
2290 ** that can be lowered at run-time using [sqlite3_limit()].
2291 ** The synopsis of the meanings of the various limits is shown below.
2292 ** Additional information is available at [limits | Limits in SQLite].
2293 **
2294 ** <dl>
2295 ** <dt>SQLITE_LIMIT_LENGTH</dt>
2296 ** <dd>The maximum size of any string or BLOB or table row.<dd>
2297 **
2298 ** <dt>SQLITE_LIMIT_SQL_LENGTH</dt>
2299 ** <dd>The maximum length of an SQL statement.</dd>
2300 **
2301 ** <dt>SQLITE_LIMIT_COLUMN</dt>
2302 ** <dd>The maximum number of columns in a table definition or in the
2303 ** result set of a [SELECT] or the maximum number of columns in an index
2304 ** or in an ORDER BY or GROUP BY clause.</dd>
2305 **
2306 ** <dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
2307 ** <dd>The maximum depth of the parse tree on any expression.</dd>
2308 **
2309 ** <dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
2310 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>
2311 **
2312 ** <dt>SQLITE_LIMIT_VDBE_OP</dt>
2313 ** <dd>The maximum number of instructions in a virtual machine program
2314 ** used to implement an SQL statement.</dd>
2315 **
2316 ** <dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
2317 ** <dd>The maximum number of arguments on a function.</dd>
2318 **
2319 ** <dt>SQLITE_LIMIT_ATTACHED</dt>
2320 ** <dd>The maximum number of [ATTACH | attached databases].</dd>
2321 **
2322 ** <dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
2323 ** <dd>The maximum length of the pattern argument to the [LIKE] or
2324 ** [GLOB] operators.</dd>
2325 **
2326 ** <dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
2327 ** <dd>The maximum number of variables in an SQL statement that can
2328 ** be bound.</dd>
2329 **
2330 ** <dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
2331 ** <dd>The maximum depth of recursion for triggers.</dd>
2332 ** </dl>
2333 */
2334 #define SQLITE_LIMIT_LENGTH 0
2335 #define SQLITE_LIMIT_SQL_LENGTH 1
2336 #define SQLITE_LIMIT_COLUMN 2
2337 #define SQLITE_LIMIT_EXPR_DEPTH 3
2338 #define SQLITE_LIMIT_COMPOUND_SELECT 4
2339 #define SQLITE_LIMIT_VDBE_OP 5
2340 #define SQLITE_LIMIT_FUNCTION_ARG 6
2341 #define SQLITE_LIMIT_ATTACHED 7
2342 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
2343 #define SQLITE_LIMIT_VARIABLE_NUMBER 9
2344 #define SQLITE_LIMIT_TRIGGER_DEPTH 10
2345
2346 /*
2347 ** CAPI3REF: Compiling An SQL Statement {H13010} <S10000>
2348 ** KEYWORDS: {SQL statement compiler}
2349 **
2350 ** To execute an SQL query, it must first be compiled into a byte-code
2351 ** program using one of these routines.
2352 **
2353 ** The first argument, "db", is a [database connection] obtained from a
2354 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
2355 ** [sqlite3_open16()]. The database connection must not have been closed.
2356 **
2357 ** The second argument, "zSql", is the statement to be compiled, encoded
2358 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
2359 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
2360 ** use UTF-16.
2361 **
2362 ** If the nByte argument is less than zero, then zSql is read up to the
2363 ** first zero terminator. If nByte is non-negative, then it is the maximum
2364 ** number of bytes read from zSql. When nByte is non-negative, the
2365 ** zSql string ends at either the first '\000' or '\u0000' character or
2366 ** the nByte-th byte, whichever comes first. If the caller knows
2367 ** that the supplied string is nul-terminated, then there is a small
2368 ** performance advantage to be gained by passing an nByte parameter that
2369 ** is equal to the number of bytes in the input string <i>including</i>
2370 ** the nul-terminator bytes.
2371 **
2372 ** If pzTail is not NULL then *pzTail is made to point to the first byte
2373 ** past the end of the first SQL statement in zSql. These routines only
2374 ** compile the first statement in zSql, so *pzTail is left pointing to
2375 ** what remains uncompiled.
2376 **
2377 ** *ppStmt is left pointing to a compiled [prepared statement] that can be
2378 ** executed using [sqlite3_step()]. If there is an error, *ppStmt is set
2379 ** to NULL. If the input text contains no SQL (if the input is an empty
2380 ** string or a comment) then *ppStmt is set to NULL.
2381 ** The calling procedure is responsible for deleting the compiled
2382 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
2383 ** ppStmt may not be NULL.
2384 **
2385 ** On success, [SQLITE_OK] is returned, otherwise an [error code] is returned.
2386 **
2387 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
2388 ** recommended for all new programs. The two older interfaces are retained
2389 ** for backwards compatibility, but their use is discouraged.
2390 ** In the "v2" interfaces, the prepared statement
2391 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
2392 ** original SQL text. This causes the [sqlite3_step()] interface to
2393 ** behave a differently in two ways:
2394 **
2395 ** <ol>
2396 ** <li>
2397 ** If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
2398 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
2399 ** statement and try to run it again. If the schema has changed in
2400 ** a way that makes the statement no longer valid, [sqlite3_step()] will still
2401 ** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is
2402 ** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the
2403 ** error go away. Note: use [sqlite3_errmsg()] to find the text
2404 ** of the parsing error that results in an [SQLITE_SCHEMA] return.
2405 ** </li>
2406 **
2407 ** <li>
2408 ** When an error occurs, [sqlite3_step()] will return one of the detailed
2409 ** [error codes] or [extended error codes]. The legacy behavior was that
2410 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
2411 ** and you would have to make a second call to [sqlite3_reset()] in order
2412 ** to find the underlying cause of the problem. With the "v2" prepare
2413 ** interfaces, the underlying reason for the error is returned immediately.
2414 ** </li>
2415 ** </ol>
2416 **
2417 ** Requirements:
2418 ** [H13011] [H13012] [H13013] [H13014] [H13015] [H13016] [H13019] [H13021]
2419 **
2420 */
2421 int sqlite3_prepare(
2422 sqlite3 *db, /* Database handle */
2423 const char *zSql, /* SQL statement, UTF-8 encoded */
2424 int nByte, /* Maximum length of zSql in bytes. */
2425 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
2426 const char **pzTail /* OUT: Pointer to unused portion of zSql */
2427 );
2428 int sqlite3_prepare_v2(
2429 sqlite3 *db, /* Database handle */
2430 const char *zSql, /* SQL statement, UTF-8 encoded */
2431 int nByte, /* Maximum length of zSql in bytes. */
2432 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
2433 const char **pzTail /* OUT: Pointer to unused portion of zSql */
2434 );
2435 int sqlite3_prepare16(
2436 sqlite3 *db, /* Database handle */
2437 const void *zSql, /* SQL statement, UTF-16 encoded */
2438 int nByte, /* Maximum length of zSql in bytes. */
2439 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
2440 const void **pzTail /* OUT: Pointer to unused portion of zSql */
2441 );
2442 int sqlite3_prepare16_v2(
2443 sqlite3 *db, /* Database handle */
2444 const void *zSql, /* SQL statement, UTF-16 encoded */
2445 int nByte, /* Maximum length of zSql in bytes. */
2446 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
2447 const void **pzTail /* OUT: Pointer to unused portion of zSql */
2448 );
2449
2450 /*
2451 ** CAPI3REF: Retrieving Statement SQL {H13100} <H13000>
2452 **
2453 ** This interface can be used to retrieve a saved copy of the original
2454 ** SQL text used to create a [prepared statement] if that statement was
2455 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
2456 **
2457 ** Requirements:
2458 ** [H13101] [H13102] [H13103]
2459 */
2460 const char *sqlite3_sql(sqlite3_stmt *pStmt);
2461
2462 /*
2463 ** CAPI3REF: Dynamically Typed Value Object {H15000} <S20200>
2464 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
2465 **
2466 ** SQLite uses the sqlite3_value object to represent all values
2467 ** that can be stored in a database table. SQLite uses dynamic typing
2468 ** for the values it stores. Values stored in sqlite3_value objects
2469 ** can be integers, floating point values, strings, BLOBs, or NULL.
2470 **
2471 ** An sqlite3_value object may be either "protected" or "unprotected".
2472 ** Some interfaces require a protected sqlite3_value. Other interfaces
2473 ** will accept either a protected or an unprotected sqlite3_value.
2474 ** Every interface that accepts sqlite3_value arguments specifies
2475 ** whether or not it requires a protected sqlite3_value.
2476 **
2477 ** The terms "protected" and "unprotected" refer to whether or not
2478 ** a mutex is held. A internal mutex is held for a protected
2479 ** sqlite3_value object but no mutex is held for an unprotected
2480 ** sqlite3_value object. If SQLite is compiled to be single-threaded
2481 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
2482 ** or if SQLite is run in one of reduced mutex modes
2483 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
2484 ** then there is no distinction between protected and unprotected
2485 ** sqlite3_value objects and they can be used interchangeably. However,
2486 ** for maximum code portability it is recommended that applications
2487 ** still make the distinction between between protected and unprotected
2488 ** sqlite3_value objects even when not strictly required.
2489 **
2490 ** The sqlite3_value objects that are passed as parameters into the
2491 ** implementation of [application-defined SQL functions] are protected.
2492 ** The sqlite3_value object returned by
2493 ** [sqlite3_column_value()] is unprotected.
2494 ** Unprotected sqlite3_value objects may only be used with
2495 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
2496 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
2497 ** interfaces require protected sqlite3_value objects.
2498 */
2499 typedef struct Mem sqlite3_value;
2500
2501 /*
2502 ** CAPI3REF: SQL Function Context Object {H16001} <S20200>
2503 **
2504 ** The context in which an SQL function executes is stored in an
2505 ** sqlite3_context object. A pointer to an sqlite3_context object
2506 ** is always first parameter to [application-defined SQL functions].
2507 ** The application-defined SQL function implementation will pass this
2508 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
2509 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
2510 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
2511 ** and/or [sqlite3_set_auxdata()].
2512 */
2513 typedef struct sqlite3_context sqlite3_context;
2514
2515 /*
2516 ** CAPI3REF: Binding Values To Prepared Statements {H13500} <S70300>
2517 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
2518 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
2519 **
2520 ** In the SQL strings input to [sqlite3_prepare_v2()] and its variants,
2521 ** literals may be replaced by a [parameter] that matches one of following
2522 ** templates:
2523 **
2524 ** <ul>
2525 ** <li> ?
2526 ** <li> ?NNN
2527 ** <li> :VVV
2528 ** <li> @VVV
2529 ** <li> $VVV
2530 ** </ul>
2531 **
2532 ** In the templates above, NNN represents an integer literal,
2533 ** and VVV represents an alphanumeric identifer. The values of these
2534 ** parameters (also called "host parameter names" or "SQL parameters")
2535 ** can be set using the sqlite3_bind_*() routines defined here.
2536 **
2537 ** The first argument to the sqlite3_bind_*() routines is always
2538 ** a pointer to the [sqlite3_stmt] object returned from
2539 ** [sqlite3_prepare_v2()] or its variants.
2540 **
2541 ** The second argument is the index of the SQL parameter to be set.
2542 ** The leftmost SQL parameter has an index of 1. When the same named
2543 ** SQL parameter is used more than once, second and subsequent
2544 ** occurrences have the same index as the first occurrence.
2545 ** The index for named parameters can be looked up using the
2546 ** [sqlite3_bind_parameter_index()] API if desired. The index
2547 ** for "?NNN" parameters is the value of NNN.
2548 ** The NNN value must be between 1 and the [sqlite3_limit()]
2549 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
2550 **
2551 ** The third argument is the value to bind to the parameter.
2552 **
2553 ** In those routines that have a fourth argument, its value is the
2554 ** number of bytes in the parameter. To be clear: the value is the
2555 ** number of <u>bytes</u> in the value, not the number of characters.
2556 ** If the fourth parameter is negative, the length of the string is
2557 ** the number of bytes up to the first zero terminator.
2558 **
2559 ** The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
2560 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
2561 ** string after SQLite has finished with it. If the fifth argument is
2562 ** the special value [SQLITE_STATIC], then SQLite assumes that the
2563 ** information is in static, unmanaged space and does not need to be freed.
2564 ** If the fifth argument has the value [SQLITE_TRANSIENT], then
2565 ** SQLite makes its own private copy of the data immediately, before
2566 ** the sqlite3_bind_*() routine returns.
2567 **
2568 ** The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
2569 ** is filled with zeroes. A zeroblob uses a fixed amount of memory
2570 ** (just an integer to hold its size) while it is being processed.
2571 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
2572 ** content is later written using
2573 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
2574 ** A negative value for the zeroblob results in a zero-length BLOB.
2575 **
2576 ** The sqlite3_bind_*() routines must be called after
2577 ** [sqlite3_prepare_v2()] (and its variants) or [sqlite3_reset()] and
2578 ** before [sqlite3_step()].
2579 ** Bindings are not cleared by the [sqlite3_reset()] routine.
2580 ** Unbound parameters are interpreted as NULL.
2581 **
2582 ** These routines return [SQLITE_OK] on success or an error code if
2583 ** anything goes wrong. [SQLITE_RANGE] is returned if the parameter
2584 ** index is out of range. [SQLITE_NOMEM] is returned if malloc() fails.
2585 ** [SQLITE_MISUSE] might be returned if these routines are called on a
2586 ** virtual machine that is the wrong state or which has already been finalized.
2587 ** Detection of misuse is unreliable. Applications should not depend
2588 ** on SQLITE_MISUSE returns. SQLITE_MISUSE is intended to indicate a
2589 ** a logic error in the application. Future versions of SQLite might
2590 ** panic rather than return SQLITE_MISUSE.
2591 **
2592 ** See also: [sqlite3_bind_parameter_count()],
2593 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
2594 **
2595 ** Requirements:
2596 ** [H13506] [H13509] [H13512] [H13515] [H13518] [H13521] [H13524] [H13527]
2597 ** [H13530] [H13533] [H13536] [H13539] [H13542] [H13545] [H13548] [H13551]
2598 **
2599 */
2600 int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
2601 int sqlite3_bind_double(sqlite3_stmt*, int, double);
2602 int sqlite3_bind_int(sqlite3_stmt*, int, int);
2603 int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
2604 int sqlite3_bind_null(sqlite3_stmt*, int);
2605 int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
2606 int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
2607 int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
2608 int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
2609
2610 /*
2611 ** CAPI3REF: Number Of SQL Parameters {H13600} <S70300>
2612 **
2613 ** This routine can be used to find the number of [SQL parameters]
2614 ** in a [prepared statement]. SQL parameters are tokens of the
2615 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
2616 ** placeholders for values that are [sqlite3_bind_blob | bound]
2617 ** to the parameters at a later time.
2618 **
2619 ** This routine actually returns the index of the largest (rightmost)
2620 ** parameter. For all forms except ?NNN, this will correspond to the
2621 ** number of unique parameters. If parameters of the ?NNN are used,
2622 ** there may be gaps in the list.
2623 **
2624 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
2625 ** [sqlite3_bind_parameter_name()], and
2626 ** [sqlite3_bind_parameter_index()].
2627 **
2628 ** Requirements:
2629 ** [H13601]
2630 */
2631 int sqlite3_bind_parameter_count(sqlite3_stmt*);
2632
2633 /*
2634 ** CAPI3REF: Name Of A Host Parameter {H13620} <S70300>
2635 **
2636 ** This routine returns a pointer to the name of the n-th
2637 ** [SQL parameter] in a [prepared statement].
2638 ** SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
2639 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
2640 ** respectively.
2641 ** In other words, the initial ":" or "$" or "@" or "?"
2642 ** is included as part of the name.
2643 ** Parameters of the form "?" without a following integer have no name
2644 ** and are also referred to as "anonymous parameters".
2645 **
2646 ** The first host parameter has an index of 1, not 0.
2647 **
2648 ** If the value n is out of range or if the n-th parameter is
2649 ** nameless, then NULL is returned. The returned string is
2650 ** always in UTF-8 encoding even if the named parameter was
2651 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
2652 ** [sqlite3_prepare16_v2()].
2653 **
2654 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
2655 ** [sqlite3_bind_parameter_count()], and
2656 ** [sqlite3_bind_parameter_index()].
2657 **
2658 ** Requirements:
2659 ** [H13621]
2660 */
2661 const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
2662
2663 /*
2664 ** CAPI3REF: Index Of A Parameter With A Given Name {H13640} <S70300>
2665 **
2666 ** Return the index of an SQL parameter given its name. The
2667 ** index value returned is suitable for use as the second
2668 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. A zero
2669 ** is returned if no matching parameter is found. The parameter
2670 ** name must be given in UTF-8 even if the original statement
2671 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
2672 **
2673 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
2674 ** [sqlite3_bind_parameter_count()], and
2675 ** [sqlite3_bind_parameter_index()].
2676 **
2677 ** Requirements:
2678 ** [H13641]
2679 */
2680 int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
2681
2682 /*
2683 ** CAPI3REF: Reset All Bindings On A Prepared Statement {H13660} <S70300>
2684 **
2685 ** Contrary to the intuition of many, [sqlite3_reset()] does not reset
2686 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
2687 ** Use this routine to reset all host parameters to NULL.
2688 **
2689 ** Requirements:
2690 ** [H13661]
2691 */
2692 int sqlite3_clear_bindings(sqlite3_stmt*);
2693
2694 /*
2695 ** CAPI3REF: Number Of Columns In A Result Set {H13710} <S10700>
2696 **
2697 ** Return the number of columns in the result set returned by the
2698 ** [prepared statement]. This routine returns 0 if pStmt is an SQL
2699 ** statement that does not return data (for example an [UPDATE]).
2700 **
2701 ** Requirements:
2702 ** [H13711]
2703 */
2704 int sqlite3_column_count(sqlite3_stmt *pStmt);
2705
2706 /*
2707 ** CAPI3REF: Column Names In A Result Set {H13720} <S10700>
2708 **
2709 ** These routines return the name assigned to a particular column
2710 ** in the result set of a [SELECT] statement. The sqlite3_column_name()
2711 ** interface returns a pointer to a zero-terminated UTF-8 string
2712 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
2713 ** UTF-16 string. The first parameter is the [prepared statement]
2714 ** that implements the [SELECT] statement. The second parameter is the
2715 ** column number. The leftmost column is number 0.
2716 **
2717 ** The returned string pointer is valid until either the [prepared statement]
2718 ** is destroyed by [sqlite3_finalize()] or until the next call to
2719 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
2720 **
2721 ** If sqlite3_malloc() fails during the processing of either routine
2722 ** (for example during a conversion from UTF-8 to UTF-16) then a
2723 ** NULL pointer is returned.
2724 **
2725 ** The name of a result column is the value of the "AS" clause for
2726 ** that column, if there is an AS clause. If there is no AS clause
2727 ** then the name of the column is unspecified and may change from
2728 ** one release of SQLite to the next.
2729 **
2730 ** Requirements:
2731 ** [H13721] [H13723] [H13724] [H13725] [H13726] [H13727]
2732 */
2733 const char *sqlite3_column_name(sqlite3_stmt*, int N);
2734 const void *sqlite3_column_name16(sqlite3_stmt*, int N);
2735
2736 /*
2737 ** CAPI3REF: Source Of Data In A Query Result {H13740} <S10700>
2738 **
2739 ** These routines provide a means to determine what column of what
2740 ** table in which database a result of a [SELECT] statement comes from.
2741 ** The name of the database or table or column can be returned as
2742 ** either a UTF-8 or UTF-16 string. The _database_ routines return
2743 ** the database name, the _table_ routines return the table name, and
2744 ** the origin_ routines return the column name.
2745 ** The returned string is valid until the [prepared statement] is destroyed
2746 ** using [sqlite3_finalize()] or until the same information is requested
2747 ** again in a different encoding.
2748 **
2749 ** The names returned are the original un-aliased names of the
2750 ** database, table, and column.
2751 **
2752 ** The first argument to the following calls is a [prepared statement].
2753 ** These functions return information about the Nth column returned by
2754 ** the statement, where N is the second function argument.
2755 **
2756 ** If the Nth column returned by the statement is an expression or
2757 ** subquery and is not a column value, then all of these functions return
2758 ** NULL. These routine might also return NULL if a memory allocation error
2759 ** occurs. Otherwise, they return the name of the attached database, table
2760 ** and column that query result column was extracted from.
2761 **
2762 ** As with all other SQLite APIs, those postfixed with "16" return
2763 ** UTF-16 encoded strings, the other functions return UTF-8. {END}
2764 **
2765 ** These APIs are only available if the library was compiled with the
2766 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
2767 **
2768 ** {A13751}
2769 ** If two or more threads call one or more of these routines against the same
2770 ** prepared statement and column at the same time then the results are
2771 ** undefined.
2772 **
2773 ** Requirements:
2774 ** [H13741] [H13742] [H13743] [H13744] [H13745] [H13746] [H13748]
2775 **
2776 ** If two or more threads call one or more
2777 ** [sqlite3_column_database_name | column metadata interfaces]
2778 ** for the same [prepared statement] and result column
2779 ** at the same time then the results are undefined.
2780 */
2781 const char *sqlite3_column_database_name(sqlite3_stmt*,int);
2782 const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
2783 const char *sqlite3_column_table_name(sqlite3_stmt*,int);
2784 const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
2785 const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
2786 const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
2787
2788 /*
2789 ** CAPI3REF: Declared Datatype Of A Query Result {H13760} <S10700>
2790 **
2791 ** The first parameter is a [prepared statement].
2792 ** If this statement is a [SELECT] statement and the Nth column of the
2793 ** returned result set of that [SELECT] is a table column (not an
2794 ** expression or subquery) then the declared type of the table
2795 ** column is returned. If the Nth column of the result set is an
2796 ** expression or subquery, then a NULL pointer is returned.
2797 ** The returned string is always UTF-8 encoded. {END}
2798 **
2799 ** For example, given the database schema:
2800 **
2801 ** CREATE TABLE t1(c1 VARIANT);
2802 **
2803 ** and the following statement to be compiled:
2804 **
2805 ** SELECT c1 + 1, c1 FROM t1;
2806 **
2807 ** this routine would return the string "VARIANT" for the second result
2808 ** column (i==1), and a NULL pointer for the first result column (i==0).
2809 **
2810 ** SQLite uses dynamic run-time typing. So just because a column
2811 ** is declared to contain a particular type does not mean that the
2812 ** data stored in that column is of the declared type. SQLite is
2813 ** strongly typed, but the typing is dynamic not static. Type
2814 ** is associated with individual values, not with the containers
2815 ** used to hold those values.
2816 **
2817 ** Requirements:
2818 ** [H13761] [H13762] [H13763]
2819 */
2820 const char *sqlite3_column_decltype(sqlite3_stmt*,int);
2821 const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
2822
2823 /*
2824 ** CAPI3REF: Evaluate An SQL Statement {H13200} <S10000>
2825 **
2826 ** After a [prepared statement] has been prepared using either
2827 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
2828 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
2829 ** must be called one or more times to evaluate the statement.
2830 **
2831 ** The details of the behavior of the sqlite3_step() interface depend
2832 ** on whether the statement was prepared using the newer "v2" interface
2833 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
2834 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
2835 ** new "v2" interface is recommended for new applications but the legacy
2836 ** interface will continue to be supported.
2837 **
2838 ** In the legacy interface, the return value will be either [SQLITE_BUSY],
2839 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
2840 ** With the "v2" interface, any of the other [result codes] or
2841 ** [extended result codes] might be returned as well.
2842 **
2843 ** [SQLITE_BUSY] means that the database engine was unable to acquire the
2844 ** database locks it needs to do its job. If the statement is a [COMMIT]
2845 ** or occurs outside of an explicit transaction, then you can retry the
2846 ** statement. If the statement is not a [COMMIT] and occurs within a
2847 ** explicit transaction then you should rollback the transaction before
2848 ** continuing.
2849 **
2850 ** [SQLITE_DONE] means that the statement has finished executing
2851 ** successfully. sqlite3_step() should not be called again on this virtual
2852 ** machine without first calling [sqlite3_reset()] to reset the virtual
2853 ** machine back to its initial state.
2854 **
2855 ** If the SQL statement being executed returns any data, then [SQLITE_ROW]
2856 ** is returned each time a new row of data is ready for processing by the
2857 ** caller. The values may be accessed using the [column access functions].
2858 ** sqlite3_step() is called again to retrieve the next row of data.
2859 **
2860 ** [SQLITE_ERROR] means that a run-time error (such as a constraint
2861 ** violation) has occurred. sqlite3_step() should not be called again on
2862 ** the VM. More information may be found by calling [sqlite3_errmsg()].
2863 ** With the legacy interface, a more specific error code (for example,
2864 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
2865 ** can be obtained by calling [sqlite3_reset()] on the
2866 ** [prepared statement]. In the "v2" interface,
2867 ** the more specific error code is returned directly by sqlite3_step().
2868 **
2869 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
2870 ** Perhaps it was called on a [prepared statement] that has
2871 ** already been [sqlite3_finalize | finalized] or on one that had
2872 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
2873 ** be the case that the same database connection is being used by two or
2874 ** more threads at the same moment in time.
2875 **
2876 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
2877 ** API always returns a generic error code, [SQLITE_ERROR], following any
2878 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
2879 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
2880 ** specific [error codes] that better describes the error.
2881 ** We admit that this is a goofy design. The problem has been fixed
2882 ** with the "v2" interface. If you prepare all of your SQL statements
2883 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
2884 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
2885 ** then the more specific [error codes] are returned directly
2886 ** by sqlite3_step(). The use of the "v2" interface is recommended.
2887 **
2888 ** Requirements:
2889 ** [H13202] [H15304] [H15306] [H15308] [H15310]
2890 */
2891 int sqlite3_step(sqlite3_stmt*);
2892
2893 /*
2894 ** CAPI3REF: Number of columns in a result set {H13770} <S10700>
2895 **
2896 ** Returns the number of values in the current row of the result set.
2897 **
2898 ** Requirements:
2899 ** [H13771] [H13772]
2900 */
2901 int sqlite3_data_count(sqlite3_stmt *pStmt);
2902
2903 /*
2904 ** CAPI3REF: Fundamental Datatypes {H10265} <S10110><S10120>
2905 ** KEYWORDS: SQLITE_TEXT
2906 **
2907 ** {H10266} Every value in SQLite has one of five fundamental datatypes:
2908 **
2909 ** <ul>
2910 ** <li> 64-bit signed integer
2911 ** <li> 64-bit IEEE floating point number
2912 ** <li> string
2913 ** <li> BLOB
2914 ** <li> NULL
2915 ** </ul> {END}
2916 **
2917 ** These constants are codes for each of those types.
2918 **
2919 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
2920 ** for a completely different meaning. Software that links against both
2921 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
2922 ** SQLITE_TEXT.
2923 */
2924 #define SQLITE_INTEGER 1
2925 #define SQLITE_FLOAT 2
2926 #define SQLITE_BLOB 4
2927 #define SQLITE_NULL 5
2928 #ifdef SQLITE_TEXT
2929 # undef SQLITE_TEXT
2930 #else
2931 # define SQLITE_TEXT 3
2932 #endif
2933 #define SQLITE3_TEXT 3
2934
2935 /*
2936 ** CAPI3REF: Result Values From A Query {H13800} <S10700>
2937 ** KEYWORDS: {column access functions}
2938 **
2939 ** These routines form the "result set query" interface.
2940 **
2941 ** These routines return information about a single column of the current
2942 ** result row of a query. In every case the first argument is a pointer
2943 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
2944 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
2945 ** and the second argument is the index of the column for which information
2946 ** should be returned. The leftmost column of the result set has the index 0.
2947 **
2948 ** If the SQL statement does not currently point to a valid row, or if the
2949 ** column index is out of range, the result is undefined.
2950 ** These routines may only be called when the most recent call to
2951 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
2952 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
2953 ** If any of these routines are called after [sqlite3_reset()] or
2954 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
2955 ** something other than [SQLITE_ROW], the results are undefined.
2956 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
2957 ** are called from a different thread while any of these routines
2958 ** are pending, then the results are undefined.
2959 **
2960 ** The sqlite3_column_type() routine returns the
2961 ** [SQLITE_INTEGER | datatype code] for the initial data type
2962 ** of the result column. The returned value is one of [SQLITE_INTEGER],
2963 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
2964 ** returned by sqlite3_column_type() is only meaningful if no type
2965 ** conversions have occurred as described below. After a type conversion,
2966 ** the value returned by sqlite3_column_type() is undefined. Future
2967 ** versions of SQLite may change the behavior of sqlite3_column_type()
2968 ** following a type conversion.
2969 **
2970 ** If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
2971 ** routine returns the number of bytes in that BLOB or string.
2972 ** If the result is a UTF-16 string, then sqlite3_column_bytes() converts
2973 ** the string to UTF-8 and then returns the number of bytes.
2974 ** If the result is a numeric value then sqlite3_column_bytes() uses
2975 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
2976 ** the number of bytes in that string.
2977 ** The value returned does not include the zero terminator at the end
2978 ** of the string. For clarity: the value returned is the number of
2979 ** bytes in the string, not the number of characters.
2980 **
2981 ** Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
2982 ** even empty strings, are always zero terminated. The return
2983 ** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary
2984 ** pointer, possibly even a NULL pointer.
2985 **
2986 ** The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes()
2987 ** but leaves the result in UTF-16 in native byte order instead of UTF-8.
2988 ** The zero terminator is not included in this count.
2989 **
2990 ** The object returned by [sqlite3_column_value()] is an
2991 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object
2992 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
2993 ** If the [unprotected sqlite3_value] object returned by
2994 ** [sqlite3_column_value()] is used in any other way, including calls
2995 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
2996 ** or [sqlite3_value_bytes()], then the behavior is undefined.
2997 **
2998 ** These routines attempt to convert the value where appropriate. For
2999 ** example, if the internal representation is FLOAT and a text result
3000 ** is requested, [sqlite3_snprintf()] is used internally to perform the
3001 ** conversion automatically. The following table details the conversions
3002 ** that are applied:
3003 **
3004 ** <blockquote>
3005 ** <table border="1">
3006 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
3007 **
3008 ** <tr><td> NULL <td> INTEGER <td> Result is 0
3009 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
3010 ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer
3011 ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer
3012 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
3013 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
3014 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
3015 ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer
3016 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
3017 ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT
3018 ** <tr><td> TEXT <td> INTEGER <td> Use atoi()
3019 ** <tr><td> TEXT <td> FLOAT <td> Use atof()
3020 ** <tr><td> TEXT <td> BLOB <td> No change
3021 ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi()
3022 ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof()
3023 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
3024 ** </table>
3025 ** </blockquote>
3026 **
3027 ** The table above makes reference to standard C library functions atoi()
3028 ** and atof(). SQLite does not really use these functions. It has its
3029 ** own equivalent internal routines. The atoi() and atof() names are
3030 ** used in the table for brevity and because they are familiar to most
3031 ** C programmers.
3032 **
3033 ** Note that when type conversions occur, pointers returned by prior
3034 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
3035 ** sqlite3_column_text16() may be invalidated.
3036 ** Type conversions and pointer invalidations might occur
3037 ** in the following cases:
3038 **
3039 ** <ul>
3040 ** <li> The initial content is a BLOB and sqlite3_column_text() or
3041 ** sqlite3_column_text16() is called. A zero-terminator might
3042 ** need to be added to the string.</li>
3043 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
3044 ** sqlite3_column_text16() is called. The content must be converted
3045 ** to UTF-16.</li>
3046 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
3047 ** sqlite3_column_text() is called. The content must be converted
3048 ** to UTF-8.</li>
3049 ** </ul>
3050 **
3051 ** Conversions between UTF-16be and UTF-16le are always done in place and do
3052 ** not invalidate a prior pointer, though of course the content of the buffer
3053 ** that the prior pointer points to will have been modified. Other kinds
3054 ** of conversion are done in place when it is possible, but sometimes they
3055 ** are not possible and in those cases prior pointers are invalidated.
3056 **
3057 ** The safest and easiest to remember policy is to invoke these routines
3058 ** in one of the following ways:
3059 **
3060 ** <ul>
3061 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
3062 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
3063 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
3064 ** </ul>
3065 **
3066 ** In other words, you should call sqlite3_column_text(),
3067 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
3068 ** into the desired format, then invoke sqlite3_column_bytes() or
3069 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
3070 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
3071 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
3072 ** with calls to sqlite3_column_bytes().
3073 **
3074 ** The pointers returned are valid until a type conversion occurs as
3075 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
3076 ** [sqlite3_finalize()] is called. The memory space used to hold strings
3077 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned
3078 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
3079 ** [sqlite3_free()].
3080 **
3081 ** If a memory allocation error occurs during the evaluation of any
3082 ** of these routines, a default value is returned. The default value
3083 ** is either the integer 0, the floating point number 0.0, or a NULL
3084 ** pointer. Subsequent calls to [sqlite3_errcode()] will return
3085 ** [SQLITE_NOMEM].
3086 **
3087 ** Requirements:
3088 ** [H13803] [H13806] [H13809] [H13812] [H13815] [H13818] [H13821] [H13824]
3089 ** [H13827] [H13830]
3090 */
3091 const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
3092 int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
3093 int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
3094 double sqlite3_column_double(sqlite3_stmt*, int iCol);
3095 int sqlite3_column_int(sqlite3_stmt*, int iCol);
3096 sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
3097 const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
3098 const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
3099 int sqlite3_column_type(sqlite3_stmt*, int iCol);
3100 sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
3101
3102 /*
3103 ** CAPI3REF: Destroy A Prepared Statement Object {H13300} <S70300><S30100>
3104 **
3105 ** The sqlite3_finalize() function is called to delete a [prepared statement].
3106 ** If the statement was executed successfully or not executed at all, then
3107 ** SQLITE_OK is returned. If execution of the statement failed then an
3108 ** [error code] or [extended error code] is returned.
3109 **
3110 ** This routine can be called at any point during the execution of the
3111 ** [prepared statement]. If the virtual machine has not
3112 ** completed execution when this routine is called, that is like
3113 ** encountering an error or an [sqlite3_interrupt | interrupt].
3114 ** Incomplete updates may be rolled back and transactions canceled,
3115 ** depending on the circumstances, and the
3116 ** [error code] returned will be [SQLITE_ABORT].
3117 **
3118 ** Requirements:
3119 ** [H11302] [H11304]
3120 */
3121 int sqlite3_finalize(sqlite3_stmt *pStmt);
3122
3123 /*
3124 ** CAPI3REF: Reset A Prepared Statement Object {H13330} <S70300>
3125 **
3126 ** The sqlite3_reset() function is called to reset a [prepared statement]
3127 ** object back to its initial state, ready to be re-executed.
3128 ** Any SQL statement variables that had values bound to them using
3129 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
3130 ** Use [sqlite3_clear_bindings()] to reset the bindings.
3131 **
3132 ** {H11332} The [sqlite3_reset(S)] interface resets the [prepared statement] S
3133 ** back to the beginning of its program.
3134 **
3135 ** {H11334} If the most recent call to [sqlite3_step(S)] for the
3136 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
3137 ** or if [sqlite3_step(S)] has never before been called on S,
3138 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
3139 **
3140 ** {H11336} If the most recent call to [sqlite3_step(S)] for the
3141 ** [prepared statement] S indicated an error, then
3142 ** [sqlite3_reset(S)] returns an appropriate [error code].
3143 **
3144 ** {H11338} The [sqlite3_reset(S)] interface does not change the values
3145 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
3146 */
3147 int sqlite3_reset(sqlite3_stmt *pStmt);
3148
3149 /*
3150 ** CAPI3REF: Create Or Redefine SQL Functions {H16100} <S20200>
3151 ** KEYWORDS: {function creation routines}
3152 ** KEYWORDS: {application-defined SQL function}
3153 ** KEYWORDS: {application-defined SQL functions}
3154 **
3155 ** These two functions (collectively known as "function creation routines")
3156 ** are used to add SQL functions or aggregates or to redefine the behavior
3157 ** of existing SQL functions or aggregates. The only difference between the
3158 ** two is that the second parameter, the name of the (scalar) function or
3159 ** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16
3160 ** for sqlite3_create_function16().
3161 **
3162 ** The first parameter is the [database connection] to which the SQL
3163 ** function is to be added. If a single program uses more than one database
3164 ** connection internally, then SQL functions must be added individually to
3165 ** each database connection.
3166 **
3167 ** The second parameter is the name of the SQL function to be created or
3168 ** redefined. The length of the name is limited to 255 bytes, exclusive of
3169 ** the zero-terminator. Note that the name length limit is in bytes, not
3170 ** characters. Any attempt to create a function with a longer name
3171 ** will result in [SQLITE_ERROR] being returned.
3172 **
3173 ** The third parameter (nArg)
3174 ** is the number of arguments that the SQL function or
3175 ** aggregate takes. If this parameter is -1, then the SQL function or
3176 ** aggregate may take any number of arguments between 0 and the limit
3177 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
3178 ** parameter is less than -1 or greater than 127 then the behavior is
3179 ** undefined.
3180 **
3181 ** The fourth parameter, eTextRep, specifies what
3182 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
3183 ** its parameters. Any SQL function implementation should be able to work
3184 ** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be
3185 ** more efficient with one encoding than another. An application may
3186 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
3187 ** times with the same function but with different values of eTextRep.
3188 ** When multiple implementations of the same function are available, SQLite
3189 ** will pick the one that involves the least amount of data conversion.
3190 ** If there is only a single implementation which does not care what text
3191 ** encoding is used, then the fourth argument should be [SQLITE_ANY].
3192 **
3193 ** The fifth parameter is an arbitrary pointer. The implementation of the
3194 ** function can gain access to this pointer using [sqlite3_user_data()].
3195 **
3196 ** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are
3197 ** pointers to C-language functions that implement the SQL function or
3198 ** aggregate. A scalar SQL function requires an implementation of the xFunc
3199 ** callback only, NULL pointers should be passed as the xStep and xFinal
3200 ** parameters. An aggregate SQL function requires an implementation of xStep
3201 ** and xFinal and NULL should be passed for xFunc. To delete an existing
3202 ** SQL function or aggregate, pass NULL for all three function callbacks.
3203 **
3204 ** It is permitted to register multiple implementations of the same
3205 ** functions with the same name but with either differing numbers of
3206 ** arguments or differing preferred text encodings. SQLite will use
3207 ** the implementation that most closely matches the way in which the
3208 ** SQL function is used. A function implementation with a non-negative
3209 ** nArg parameter is a better match than a function implementation with
3210 ** a negative nArg. A function where the preferred text encoding
3211 ** matches the database encoding is a better
3212 ** match than a function where the encoding is different.
3213 ** A function where the encoding difference is between UTF16le and UTF16be
3214 ** is a closer match than a function where the encoding difference is
3215 ** between UTF8 and UTF16.
3216 **
3217 ** Built-in functions may be overloaded by new application-defined functions.
3218 ** The first application-defined function with a given name overrides all
3219 ** built-in functions in the same [database connection] with the same name.
3220 ** Subsequent application-defined functions of the same name only override
3221 ** prior application-defined functions that are an exact match for the
3222 ** number of parameters and preferred encoding.
3223 **
3224 ** An application-defined function is permitted to call other
3225 ** SQLite interfaces. However, such calls must not
3226 ** close the database connection nor finalize or reset the prepared
3227 ** statement in which the function is running.
3228 **
3229 ** Requirements:
3230 ** [H16103] [H16106] [H16109] [H16112] [H16118] [H16121] [H16127]
3231 ** [H16130] [H16133] [H16136] [H16139] [H16142]
3232 */
3233 int sqlite3_create_function(
3234 sqlite3 *db,
3235 const char *zFunctionName,
3236 int nArg,
3237 int eTextRep,
3238 void *pApp,
3239 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3240 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3241 void (*xFinal)(sqlite3_context*)
3242 );
3243 int sqlite3_create_function16(
3244 sqlite3 *db,
3245 const void *zFunctionName,
3246 int nArg,
3247 int eTextRep,
3248 void *pApp,
3249 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3250 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3251 void (*xFinal)(sqlite3_context*)
3252 );
3253
3254 /*
3255 ** CAPI3REF: Text Encodings {H10267} <S50200> <H16100>
3256 **
3257 ** These constant define integer codes that represent the various
3258 ** text encodings supported by SQLite.
3259 */
3260 #define SQLITE_UTF8 1
3261 #define SQLITE_UTF16LE 2
3262 #define SQLITE_UTF16BE 3
3263 #define SQLITE_UTF16 4 /* Use native byte order */
3264 #define SQLITE_ANY 5 /* sqlite3_create_function only */
3265 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
3266
3267 /*
3268 ** CAPI3REF: Deprecated Functions
3269 ** DEPRECATED
3270 **
3271 ** These functions are [deprecated]. In order to maintain
3272 ** backwards compatibility with older code, these functions continue
3273 ** to be supported. However, new applications should avoid
3274 ** the use of these functions. To help encourage people to avoid
3275 ** using these functions, we are not going to tell you what they do.
3276 */
3277 #ifndef SQLITE_OMIT_DEPRECATED
3278 SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
3279 SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
3280 SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
3281 SQLITE_DEPRECATED int sqlite3_global_recover(void);
3282 SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
3283 SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void *,sqlite3_int64);
3284 #endif
3285
3286 /*
3287 ** CAPI3REF: Obtaining SQL Function Parameter Values {H15100} <S20200>
3288 **
3289 ** The C-language implementation of SQL functions and aggregates uses
3290 ** this set of interface routines to access the parameter values on
3291 ** the function or aggregate.
3292 **
3293 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
3294 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
3295 ** define callbacks that implement the SQL functions and aggregates.
3296 ** The 4th parameter to these callbacks is an array of pointers to
3297 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
3298 ** each parameter to the SQL function. These routines are used to
3299 ** extract values from the [sqlite3_value] objects.
3300 **
3301 ** These routines work only with [protected sqlite3_value] objects.
3302 ** Any attempt to use these routines on an [unprotected sqlite3_value]
3303 ** object results in undefined behavior.
3304 **
3305 ** These routines work just like the corresponding [column access functions]
3306 ** except that these routines take a single [protected sqlite3_value] object
3307 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
3308 **
3309 ** The sqlite3_value_text16() interface extracts a UTF-16 string
3310 ** in the native byte-order of the host machine. The
3311 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
3312 ** extract UTF-16 strings as big-endian and little-endian respectively.
3313 **
3314 ** The sqlite3_value_numeric_type() interface attempts to apply
3315 ** numeric affinity to the value. This means that an attempt is
3316 ** made to convert the value to an integer or floating point. If
3317 ** such a conversion is possible without loss of information (in other
3318 ** words, if the value is a string that looks like a number)
3319 ** then the conversion is performed. Otherwise no conversion occurs.
3320 ** The [SQLITE_INTEGER | datatype] after conversion is returned.
3321 **
3322 ** Please pay particular attention to the fact that the pointer returned
3323 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
3324 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
3325 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
3326 ** or [sqlite3_value_text16()].
3327 **
3328 ** These routines must be called from the same thread as
3329 ** the SQL function that supplied the [sqlite3_value*] parameters.
3330 **
3331 ** Requirements:
3332 ** [H15103] [H15106] [H15109] [H15112] [H15115] [H15118] [H15121] [H15124]
3333 ** [H15127] [H15130] [H15133] [H15136]
3334 */
3335 const void *sqlite3_value_blob(sqlite3_value*);
3336 int sqlite3_value_bytes(sqlite3_value*);
3337 int sqlite3_value_bytes16(sqlite3_value*);
3338 double sqlite3_value_double(sqlite3_value*);
3339 int sqlite3_value_int(sqlite3_value*);
3340 sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
3341 const unsigned char *sqlite3_value_text(sqlite3_value*);
3342 const void *sqlite3_value_text16(sqlite3_value*);
3343 const void *sqlite3_value_text16le(sqlite3_value*);
3344 const void *sqlite3_value_text16be(sqlite3_value*);
3345 int sqlite3_value_type(sqlite3_value*);
3346 int sqlite3_value_numeric_type(sqlite3_value*);
3347
3348 /*
3349 ** CAPI3REF: Obtain Aggregate Function Context {H16210} <S20200>
3350 **
3351 ** The implementation of aggregate SQL functions use this routine to allocate
3352 ** a structure for storing their state.
3353 **
3354 ** The first time the sqlite3_aggregate_context() routine is called for a
3355 ** particular aggregate, SQLite allocates nBytes of memory, zeroes out that
3356 ** memory, and returns a pointer to it. On second and subsequent calls to
3357 ** sqlite3_aggregate_context() for the same aggregate function index,
3358 ** the same buffer is returned. The implementation of the aggregate can use
3359 ** the returned buffer to accumulate data.
3360 **
3361 ** SQLite automatically frees the allocated buffer when the aggregate
3362 ** query concludes.
3363 **
3364 ** The first parameter should be a copy of the
3365 ** [sqlite3_context | SQL function context] that is the first parameter
3366 ** to the callback routine that implements the aggregate function.
3367 **
3368 ** This routine must be called from the same thread in which
3369 ** the aggregate SQL function is running.
3370 **
3371 ** Requirements:
3372 ** [H16211] [H16213] [H16215] [H16217]
3373 */
3374 void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
3375
3376 /*
3377 ** CAPI3REF: User Data For Functions {H16240} <S20200>
3378 **
3379 ** The sqlite3_user_data() interface returns a copy of
3380 ** the pointer that was the pUserData parameter (the 5th parameter)
3381 ** of the [sqlite3_create_function()]
3382 ** and [sqlite3_create_function16()] routines that originally
3383 ** registered the application defined function. {END}
3384 **
3385 ** This routine must be called from the same thread in which
3386 ** the application-defined function is running.
3387 **
3388 ** Requirements:
3389 ** [H16243]
3390 */
3391 void *sqlite3_user_data(sqlite3_context*);
3392
3393 /*
3394 ** CAPI3REF: Database Connection For Functions {H16250} <S60600><S20200>
3395 **
3396 ** The sqlite3_context_db_handle() interface returns a copy of
3397 ** the pointer to the [database connection] (the 1st parameter)
3398 ** of the [sqlite3_create_function()]
3399 ** and [sqlite3_create_function16()] routines that originally
3400 ** registered the application defined function.
3401 **
3402 ** Requirements:
3403 ** [H16253]
3404 */
3405 sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
3406
3407 /*
3408 ** CAPI3REF: Function Auxiliary Data {H16270} <S20200>
3409 **
3410 ** The following two functions may be used by scalar SQL functions to
3411 ** associate metadata with argument values. If the same value is passed to
3412 ** multiple invocations of the same SQL function during query execution, under
3413 ** some circumstances the associated metadata may be preserved. This may
3414 ** be used, for example, to add a regular-expression matching scalar
3415 ** function. The compiled version of the regular expression is stored as
3416 ** metadata associated with the SQL value passed as the regular expression
3417 ** pattern. The compiled regular expression can be reused on multiple
3418 ** invocations of the same function so that the original pattern string
3419 ** does not need to be recompiled on each invocation.
3420 **
3421 ** The sqlite3_get_auxdata() interface returns a pointer to the metadata
3422 ** associated by the sqlite3_set_auxdata() function with the Nth argument
3423 ** value to the application-defined function. If no metadata has been ever
3424 ** been set for the Nth argument of the function, or if the corresponding
3425 ** function parameter has changed since the meta-data was set,
3426 ** then sqlite3_get_auxdata() returns a NULL pointer.
3427 **
3428 ** The sqlite3_set_auxdata() interface saves the metadata
3429 ** pointed to by its 3rd parameter as the metadata for the N-th
3430 ** argument of the application-defined function. Subsequent
3431 ** calls to sqlite3_get_auxdata() might return this data, if it has
3432 ** not been destroyed.
3433 ** If it is not NULL, SQLite will invoke the destructor
3434 ** function given by the 4th parameter to sqlite3_set_auxdata() on
3435 ** the metadata when the corresponding function parameter changes
3436 ** or when the SQL statement completes, whichever comes first.
3437 **
3438 ** SQLite is free to call the destructor and drop metadata on any
3439 ** parameter of any function at any time. The only guarantee is that
3440 ** the destructor will be called before the metadata is dropped.
3441 **
3442 ** In practice, metadata is preserved between function calls for
3443 ** expressions that are constant at compile time. This includes literal
3444 ** values and SQL variables.
3445 **
3446 ** These routines must be called from the same thread in which
3447 ** the SQL function is running.
3448 **
3449 ** Requirements:
3450 ** [H16272] [H16274] [H16276] [H16277] [H16278] [H16279]
3451 */
3452 void *sqlite3_get_auxdata(sqlite3_context*, int N);
3453 void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
3454
3455
3456 /*
3457 ** CAPI3REF: Constants Defining Special Destructor Behavior {H10280} <S30100>
3458 **
3459 ** These are special values for the destructor that is passed in as the
3460 ** final argument to routines like [sqlite3_result_blob()]. If the destructor
3461 ** argument is SQLITE_STATIC, it means that the content pointer is constant
3462 ** and will never change. It does not need to be destroyed. The
3463 ** SQLITE_TRANSIENT value means that the content will likely change in
3464 ** the near future and that SQLite should make its own private copy of
3465 ** the content before returning.
3466 **
3467 ** The typedef is necessary to work around problems in certain
3468 ** C++ compilers. See ticket #2191.
3469 */
3470 typedef void (*sqlite3_destructor_type)(void*);
3471 #define SQLITE_STATIC ((sqlite3_destructor_type)0)
3472 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
3473
3474 /*
3475 ** CAPI3REF: Setting The Result Of An SQL Function {H16400} <S20200>
3476 **
3477 ** These routines are used by the xFunc or xFinal callbacks that
3478 ** implement SQL functions and aggregates. See
3479 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
3480 ** for additional information.
3481 **
3482 ** These functions work very much like the [parameter binding] family of
3483 ** functions used to bind values to host parameters in prepared statements.
3484 ** Refer to the [SQL parameter] documentation for additional information.
3485 **
3486 ** The sqlite3_result_blob() interface sets the result from
3487 ** an application-defined function to be the BLOB whose content is pointed
3488 ** to by the second parameter and which is N bytes long where N is the
3489 ** third parameter.
3490 **
3491 ** The sqlite3_result_zeroblob() interfaces set the result of
3492 ** the application-defined function to be a BLOB containing all zero
3493 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
3494 **
3495 ** The sqlite3_result_double() interface sets the result from
3496 ** an application-defined function to be a floating point value specified
3497 ** by its 2nd argument.
3498 **
3499 ** The sqlite3_result_error() and sqlite3_result_error16() functions
3500 ** cause the implemented SQL function to throw an exception.
3501 ** SQLite uses the string pointed to by the
3502 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
3503 ** as the text of an error message. SQLite interprets the error
3504 ** message string from sqlite3_result_error() as UTF-8. SQLite
3505 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
3506 ** byte order. If the third parameter to sqlite3_result_error()
3507 ** or sqlite3_result_error16() is negative then SQLite takes as the error
3508 ** message all text up through the first zero character.
3509 ** If the third parameter to sqlite3_result_error() or
3510 ** sqlite3_result_error16() is non-negative then SQLite takes that many
3511 ** bytes (not characters) from the 2nd parameter as the error message.
3512 ** The sqlite3_result_error() and sqlite3_result_error16()
3513 ** routines make a private copy of the error message text before
3514 ** they return. Hence, the calling function can deallocate or
3515 ** modify the text after they return without harm.
3516 ** The sqlite3_result_error_code() function changes the error code
3517 ** returned by SQLite as a result of an error in a function. By default,
3518 ** the error code is SQLITE_ERROR. A subsequent call to sqlite3_result_error()
3519 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
3520 **
3521 ** The sqlite3_result_toobig() interface causes SQLite to throw an error
3522 ** indicating that a string or BLOB is to long to represent.
3523 **
3524 ** The sqlite3_result_nomem() interface causes SQLite to throw an error
3525 ** indicating that a memory allocation failed.
3526 **
3527 ** The sqlite3_result_int() interface sets the return value
3528 ** of the application-defined function to be the 32-bit signed integer
3529 ** value given in the 2nd argument.
3530 ** The sqlite3_result_int64() interface sets the return value
3531 ** of the application-defined function to be the 64-bit signed integer
3532 ** value given in the 2nd argument.
3533 **
3534 ** The sqlite3_result_null() interface sets the return value
3535 ** of the application-defined function to be NULL.
3536 **
3537 ** The sqlite3_result_text(), sqlite3_result_text16(),
3538 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
3539 ** set the return value of the application-defined function to be
3540 ** a text string which is represented as UTF-8, UTF-16 native byte order,
3541 ** UTF-16 little endian, or UTF-16 big endian, respectively.
3542 ** SQLite takes the text result from the application from
3543 ** the 2nd parameter of the sqlite3_result_text* interfaces.
3544 ** If the 3rd parameter to the sqlite3_result_text* interfaces
3545 ** is negative, then SQLite takes result text from the 2nd parameter
3546 ** through the first zero character.
3547 ** If the 3rd parameter to the sqlite3_result_text* interfaces
3548 ** is non-negative, then as many bytes (not characters) of the text
3549 ** pointed to by the 2nd parameter are taken as the application-defined
3550 ** function result.
3551 ** If the 4th parameter to the sqlite3_result_text* interfaces
3552 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
3553 ** function as the destructor on the text or BLOB result when it has
3554 ** finished using that result.
3555 ** If the 4th parameter to the sqlite3_result_text* interfaces or to
3556 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
3557 ** assumes that the text or BLOB result is in constant space and does not
3558 ** copy the content of the parameter nor call a destructor on the content
3559 ** when it has finished using that result.
3560 ** If the 4th parameter to the sqlite3_result_text* interfaces
3561 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
3562 ** then SQLite makes a copy of the result into space obtained from
3563 ** from [sqlite3_malloc()] before it returns.
3564 **
3565 ** The sqlite3_result_value() interface sets the result of
3566 ** the application-defined function to be a copy the
3567 ** [unprotected sqlite3_value] object specified by the 2nd parameter. The
3568 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
3569 ** so that the [sqlite3_value] specified in the parameter may change or
3570 ** be deallocated after sqlite3_result_value() returns without harm.
3571 ** A [protected sqlite3_value] object may always be used where an
3572 ** [unprotected sqlite3_value] object is required, so either
3573 ** kind of [sqlite3_value] object can be used with this interface.
3574 **
3575 ** If these routines are called from within the different thread
3576 ** than the one containing the application-defined function that received
3577 ** the [sqlite3_context] pointer, the results are undefined.
3578 **
3579 ** Requirements:
3580 ** [H16403] [H16406] [H16409] [H16412] [H16415] [H16418] [H16421] [H16424]
3581 ** [H16427] [H16430] [H16433] [H16436] [H16439] [H16442] [H16445] [H16448]
3582 ** [H16451] [H16454] [H16457] [H16460] [H16463]
3583 */
3584 void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
3585 void sqlite3_result_double(sqlite3_context*, double);
3586 void sqlite3_result_error(sqlite3_context*, const char*, int);
3587 void sqlite3_result_error16(sqlite3_context*, const void*, int);
3588 void sqlite3_result_error_toobig(sqlite3_context*);
3589 void sqlite3_result_error_nomem(sqlite3_context*);
3590 void sqlite3_result_error_code(sqlite3_context*, int);
3591 void sqlite3_result_int(sqlite3_context*, int);
3592 void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
3593 void sqlite3_result_null(sqlite3_context*);
3594 void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
3595 void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
3596 void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
3597 void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
3598 void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
3599 void sqlite3_result_zeroblob(sqlite3_context*, int n);
3600
3601 /*
3602 ** CAPI3REF: Define New Collating Sequences {H16600} <S20300>
3603 **
3604 ** These functions are used to add new collation sequences to the
3605 ** [database connection] specified as the first argument.
3606 **
3607 ** The name of the new collation sequence is specified as a UTF-8 string
3608 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
3609 ** and a UTF-16 string for sqlite3_create_collation16(). In all cases
3610 ** the name is passed as the second function argument.
3611 **
3612 ** The third argument may be one of the constants [SQLITE_UTF8],
3613 ** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied
3614 ** routine expects to be passed pointers to strings encoded using UTF-8,
3615 ** UTF-16 little-endian, or UTF-16 big-endian, respectively. The
3616 ** third argument might also be [SQLITE_UTF16] to indicate that the routine
3617 ** expects pointers to be UTF-16 strings in the native byte order, or the
3618 ** argument can be [SQLITE_UTF16_ALIGNED] if the
3619 ** the routine expects pointers to 16-bit word aligned strings
3620 ** of UTF-16 in the native byte order.
3621 **
3622 ** A pointer to the user supplied routine must be passed as the fifth
3623 ** argument. If it is NULL, this is the same as deleting the collation
3624 ** sequence (so that SQLite cannot call it anymore).
3625 ** Each time the application supplied function is invoked, it is passed
3626 ** as its first parameter a copy of the void* passed as the fourth argument
3627 ** to sqlite3_create_collation() or sqlite3_create_collation16().
3628 **
3629 ** The remaining arguments to the application-supplied routine are two strings,
3630 ** each represented by a (length, data) pair and encoded in the encoding
3631 ** that was passed as the third argument when the collation sequence was
3632 ** registered. {END} The application defined collation routine should
3633 ** return negative, zero or positive if the first string is less than,
3634 ** equal to, or greater than the second string. i.e. (STRING1 - STRING2).
3635 **
3636 ** The sqlite3_create_collation_v2() works like sqlite3_create_collation()
3637 ** except that it takes an extra argument which is a destructor for
3638 ** the collation. The destructor is called when the collation is
3639 ** destroyed and is passed a copy of the fourth parameter void* pointer
3640 ** of the sqlite3_create_collation_v2().
3641 ** Collations are destroyed when they are overridden by later calls to the
3642 ** collation creation functions or when the [database connection] is closed
3643 ** using [sqlite3_close()].
3644 **
3645 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
3646 **
3647 ** Requirements:
3648 ** [H16603] [H16604] [H16606] [H16609] [H16612] [H16615] [H16618] [H16621]
3649 ** [H16624] [H16627] [H16630]
3650 */
3651 int sqlite3_create_collation(
3652 sqlite3*,
3653 const char *zName,
3654 int eTextRep,
3655 void*,
3656 int(*xCompare)(void*,int,const void*,int,const void*)
3657 );
3658 int sqlite3_create_collation_v2(
3659 sqlite3*,
3660 const char *zName,
3661 int eTextRep,
3662 void*,
3663 int(*xCompare)(void*,int,const void*,int,const void*),
3664 void(*xDestroy)(void*)
3665 );
3666 int sqlite3_create_collation16(
3667 sqlite3*,
3668 const void *zName,
3669 int eTextRep,
3670 void*,
3671 int(*xCompare)(void*,int,const void*,int,const void*)
3672 );
3673
3674 /*
3675 ** CAPI3REF: Collation Needed Callbacks {H16700} <S20300>
3676 **
3677 ** To avoid having to register all collation sequences before a database
3678 ** can be used, a single callback function may be registered with the
3679 ** [database connection] to be called whenever an undefined collation
3680 ** sequence is required.
3681 **
3682 ** If the function is registered using the sqlite3_collation_needed() API,
3683 ** then it is passed the names of undefined collation sequences as strings
3684 ** encoded in UTF-8. {H16703} If sqlite3_collation_needed16() is used,
3685 ** the names are passed as UTF-16 in machine native byte order.
3686 ** A call to either function replaces any existing callback.
3687 **
3688 ** When the callback is invoked, the first argument passed is a copy
3689 ** of the second argument to sqlite3_collation_needed() or
3690 ** sqlite3_collation_needed16(). The second argument is the database
3691 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
3692 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
3693 ** sequence function required. The fourth parameter is the name of the
3694 ** required collation sequence.
3695 **
3696 ** The callback function should register the desired collation using
3697 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
3698 ** [sqlite3_create_collation_v2()].
3699 **
3700 ** Requirements:
3701 ** [H16702] [H16704] [H16706]
3702 */
3703 int sqlite3_collation_needed(
3704 sqlite3*,
3705 void*,
3706 void(*)(void*,sqlite3*,int eTextRep,const char*)
3707 );
3708 int sqlite3_collation_needed16(
3709 sqlite3*,
3710 void*,
3711 void(*)(void*,sqlite3*,int eTextRep,const void*)
3712 );
3713
3714 /*
3715 ** Specify the key for an encrypted database. This routine should be
3716 ** called right after sqlite3_open().
3717 **
3718 ** The code to implement this API is not available in the public release
3719 ** of SQLite.
3720 */
3721 int sqlite3_key(
3722 sqlite3 *db, /* Database to be rekeyed */
3723 const void *pKey, int nKey /* The key */
3724 );
3725
3726 /*
3727 ** Change the key on an open database. If the current database is not
3728 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
3729 ** database is decrypted.
3730 **
3731 ** The code to implement this API is not available in the public release
3732 ** of SQLite.
3733 */
3734 int sqlite3_rekey(
3735 sqlite3 *db, /* Database to be rekeyed */
3736 const void *pKey, int nKey /* The new key */
3737 );
3738
3739 /*
3740 ** CAPI3REF: Suspend Execution For A Short Time {H10530} <S40410>
3741 **
3742 ** The sqlite3_sleep() function causes the current thread to suspend execution
3743 ** for at least a number of milliseconds specified in its parameter.
3744 **
3745 ** If the operating system does not support sleep requests with
3746 ** millisecond time resolution, then the time will be rounded up to
3747 ** the nearest second. The number of milliseconds of sleep actually
3748 ** requested from the operating system is returned.
3749 **
3750 ** SQLite implements this interface by calling the xSleep()
3751 ** method of the default [sqlite3_vfs] object.
3752 **
3753 ** Requirements: [H10533] [H10536]
3754 */
3755 int sqlite3_sleep(int);
3756
3757 /*
3758 ** CAPI3REF: Name Of The Folder Holding Temporary Files {H10310} <S20000>
3759 **
3760 ** If this global variable is made to point to a string which is
3761 ** the name of a folder (a.k.a. directory), then all temporary files
3762 ** created by SQLite will be placed in that directory. If this variable
3763 ** is a NULL pointer, then SQLite performs a search for an appropriate
3764 ** temporary file directory.
3765 **
3766 ** It is not safe to read or modify this variable in more than one
3767 ** thread at a time. It is not safe to read or modify this variable
3768 ** if a [database connection] is being used at the same time in a separate
3769 ** thread.
3770 ** It is intended that this variable be set once
3771 ** as part of process initialization and before any SQLite interface
3772 ** routines have been called and that this variable remain unchanged
3773 ** thereafter.
3774 **
3775 ** The [temp_store_directory pragma] may modify this variable and cause
3776 ** it to point to memory obtained from [sqlite3_malloc]. Furthermore,
3777 ** the [temp_store_directory pragma] always assumes that any string
3778 ** that this variable points to is held in memory obtained from
3779 ** [sqlite3_malloc] and the pragma may attempt to free that memory
3780 ** using [sqlite3_free].
3781 ** Hence, if this variable is modified directly, either it should be
3782 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
3783 ** or else the use of the [temp_store_directory pragma] should be avoided.
3784 */
3785 SQLITE_EXTERN char *sqlite3_temp_directory;
3786
3787 /*
3788 ** CAPI3REF: Test For Auto-Commit Mode {H12930} <S60200>
3789 ** KEYWORDS: {autocommit mode}
3790 **
3791 ** The sqlite3_get_autocommit() interface returns non-zero or
3792 ** zero if the given database connection is or is not in autocommit mode,
3793 ** respectively. Autocommit mode is on by default.
3794 ** Autocommit mode is disabled by a [BEGIN] statement.
3795 ** Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
3796 **
3797 ** If certain kinds of errors occur on a statement within a multi-statement
3798 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
3799 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
3800 ** transaction might be rolled back automatically. The only way to
3801 ** find out whether SQLite automatically rolled back the transaction after
3802 ** an error is to use this function.
3803 **
3804 ** If another thread changes the autocommit status of the database
3805 ** connection while this routine is running, then the return value
3806 ** is undefined.
3807 **
3808 ** Requirements: [H12931] [H12932] [H12933] [H12934]
3809 */
3810 int sqlite3_get_autocommit(sqlite3*);
3811
3812 /*
3813 ** CAPI3REF: Find The Database Handle Of A Prepared Statement {H13120} <S60600>
3814 **
3815 ** The sqlite3_db_handle interface returns the [database connection] handle
3816 ** to which a [prepared statement] belongs. The [database connection]
3817 ** returned by sqlite3_db_handle is the same [database connection] that was the first argument
3818 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
3819 ** create the statement in the first place.
3820 **
3821 ** Requirements: [H13123]
3822 */
3823 sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
3824
3825 /*
3826 ** CAPI3REF: Find the next prepared statement {H13140} <S60600>
3827 **
3828 ** This interface returns a pointer to the next [prepared statement] after
3829 ** pStmt associated with the [database connection] pDb. If pStmt is NULL
3830 ** then this interface returns a pointer to the first prepared statement
3831 ** associated with the database connection pDb. If no prepared statement
3832 ** satisfies the conditions of this routine, it returns NULL.
3833 **
3834 ** The [database connection] pointer D in a call to
3835 ** [sqlite3_next_stmt(D,S)] must refer to an open database
3836 ** connection and in particular must not be a NULL pointer.
3837 **
3838 ** Requirements: [H13143] [H13146] [H13149] [H13152]
3839 */
3840 sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
3841
3842 /*
3843 ** CAPI3REF: Commit And Rollback Notification Callbacks {H12950} <S60400>
3844 **
3845 ** The sqlite3_commit_hook() interface registers a callback
3846 ** function to be invoked whenever a transaction is [COMMIT | committed].
3847 ** Any callback set by a previous call to sqlite3_commit_hook()
3848 ** for the same database connection is overridden.
3849 ** The sqlite3_rollback_hook() interface registers a callback
3850 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
3851 ** Any callback set by a previous call to sqlite3_commit_hook()
3852 ** for the same database connection is overridden.
3853 ** The pArg argument is passed through to the callback.
3854 ** If the callback on a commit hook function returns non-zero,
3855 ** then the commit is converted into a rollback.
3856 **
3857 ** If another function was previously registered, its
3858 ** pArg value is returned. Otherwise NULL is returned.
3859 **
3860 ** The callback implementation must not do anything that will modify
3861 ** the database connection that invoked the callback. Any actions
3862 ** to modify the database connection must be deferred until after the
3863 ** completion of the [sqlite3_step()] call that triggered the commit
3864 ** or rollback hook in the first place.
3865 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3866 ** database connections for the meaning of "modify" in this paragraph.
3867 **
3868 ** Registering a NULL function disables the callback.
3869 **
3870 ** When the commit hook callback routine returns zero, the [COMMIT]
3871 ** operation is allowed to continue normally. If the commit hook
3872 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
3873 ** The rollback hook is invoked on a rollback that results from a commit
3874 ** hook returning non-zero, just as it would be with any other rollback.
3875 **
3876 ** For the purposes of this API, a transaction is said to have been
3877 ** rolled back if an explicit "ROLLBACK" statement is executed, or
3878 ** an error or constraint causes an implicit rollback to occur.
3879 ** The rollback callback is not invoked if a transaction is
3880 ** automatically rolled back because the database connection is closed.
3881 ** The rollback callback is not invoked if a transaction is
3882 ** rolled back because a commit callback returned non-zero.
3883 ** <todo> Check on this </todo>
3884 **
3885 ** See also the [sqlite3_update_hook()] interface.
3886 **
3887 ** Requirements:
3888 ** [H12951] [H12952] [H12953] [H12954] [H12955]
3889 ** [H12961] [H12962] [H12963] [H12964]
3890 */
3891 void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
3892 void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
3893
3894 /*
3895 ** CAPI3REF: Data Change Notification Callbacks {H12970} <S60400>
3896 **
3897 ** The sqlite3_update_hook() interface registers a callback function
3898 ** with the [database connection] identified by the first argument
3899 ** to be invoked whenever a row is updated, inserted or deleted.
3900 ** Any callback set by a previous call to this function
3901 ** for the same database connection is overridden.
3902 **
3903 ** The second argument is a pointer to the function to invoke when a
3904 ** row is updated, inserted or deleted.
3905 ** The first argument to the callback is a copy of the third argument
3906 ** to sqlite3_update_hook().
3907 ** The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
3908 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
3909 ** to be invoked.
3910 ** The third and fourth arguments to the callback contain pointers to the
3911 ** database and table name containing the affected row.
3912 ** The final callback parameter is the [rowid] of the row.
3913 ** In the case of an update, this is the [rowid] after the update takes place.
3914 **
3915 ** The update hook is not invoked when internal system tables are
3916 ** modified (i.e. sqlite_master and sqlite_sequence).
3917 **
3918 ** In the current implementation, the update hook
3919 ** is not invoked when duplication rows are deleted because of an
3920 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. Nor is the update hook
3921 ** invoked when rows are deleted using the [truncate optimization].
3922 ** The exceptions defined in this paragraph might change in a future
3923 ** release of SQLite.
3924 **
3925 ** The update hook implementation must not do anything that will modify
3926 ** the database connection that invoked the update hook. Any actions
3927 ** to modify the database connection must be deferred until after the
3928 ** completion of the [sqlite3_step()] call that triggered the update hook.
3929 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3930 ** database connections for the meaning of "modify" in this paragraph.
3931 **
3932 ** If another function was previously registered, its pArg value
3933 ** is returned. Otherwise NULL is returned.
3934 **
3935 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
3936 ** interfaces.
3937 **
3938 ** Requirements:
3939 ** [H12971] [H12973] [H12975] [H12977] [H12979] [H12981] [H12983] [H12986]
3940 */
3941 void *sqlite3_update_hook(
3942 sqlite3*,
3943 void(*)(void *,int ,char const *,char const *,sqlite3_int64),
3944 void*
3945 );
3946
3947 /*
3948 ** CAPI3REF: Enable Or Disable Shared Pager Cache {H10330} <S30900>
3949 ** KEYWORDS: {shared cache}
3950 **
3951 ** This routine enables or disables the sharing of the database cache
3952 ** and schema data structures between [database connection | connections]
3953 ** to the same database. Sharing is enabled if the argument is true
3954 ** and disabled if the argument is false.
3955 **
3956 ** Cache sharing is enabled and disabled for an entire process.
3957 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
3958 ** sharing was enabled or disabled for each thread separately.
3959 **
3960 ** The cache sharing mode set by this interface effects all subsequent
3961 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
3962 ** Existing database connections continue use the sharing mode
3963 ** that was in effect at the time they were opened.
3964 **
3965 ** Virtual tables cannot be used with a shared cache. When shared
3966 ** cache is enabled, the [sqlite3_create_module()] API used to register
3967 ** virtual tables will always return an error.
3968 **
3969 ** This routine returns [SQLITE_OK] if shared cache was enabled or disabled
3970 ** successfully. An [error code] is returned otherwise.
3971 **
3972 ** Shared cache is disabled by default. But this might change in
3973 ** future releases of SQLite. Applications that care about shared
3974 ** cache setting should set it explicitly.
3975 **
3976 ** See Also: [SQLite Shared-Cache Mode]
3977 **
3978 ** Requirements: [H10331] [H10336] [H10337] [H10339]
3979 */
3980 int sqlite3_enable_shared_cache(int);
3981
3982 /*
3983 ** CAPI3REF: Attempt To Free Heap Memory {H17340} <S30220>
3984 **
3985 ** The sqlite3_release_memory() interface attempts to free N bytes
3986 ** of heap memory by deallocating non-essential memory allocations
3987 ** held by the database library. {END} Memory used to cache database
3988 ** pages to improve performance is an example of non-essential memory.
3989 ** sqlite3_release_memory() returns the number of bytes actually freed,
3990 ** which might be more or less than the amount requested.
3991 **
3992 ** Requirements: [H17341] [H17342]
3993 */
3994 int sqlite3_release_memory(int);
3995
3996 /*
3997 ** CAPI3REF: Impose A Limit On Heap Size {H17350} <S30220>
3998 **
3999 ** The sqlite3_soft_heap_limit() interface places a "soft" limit
4000 ** on the amount of heap memory that may be allocated by SQLite.
4001 ** If an internal allocation is requested that would exceed the
4002 ** soft heap limit, [sqlite3_release_memory()] is invoked one or
4003 ** more times to free up some space before the allocation is performed.
4004 **
4005 ** The limit is called "soft", because if [sqlite3_release_memory()]
4006 ** cannot free sufficient memory to prevent the limit from being exceeded,
4007 ** the memory is allocated anyway and the current operation proceeds.
4008 **
4009 ** A negative or zero value for N means that there is no soft heap limit and
4010 ** [sqlite3_release_memory()] will only be called when memory is exhausted.
4011 ** The default value for the soft heap limit is zero.
4012 **
4013 ** SQLite makes a best effort to honor the soft heap limit.
4014 ** But if the soft heap limit cannot be honored, execution will
4015 ** continue without error or notification. This is why the limit is
4016 ** called a "soft" limit. It is advisory only.
4017 **
4018 ** Prior to SQLite version 3.5.0, this routine only constrained the memory
4019 ** allocated by a single thread - the same thread in which this routine
4020 ** runs. Beginning with SQLite version 3.5.0, the soft heap limit is
4021 ** applied to all threads. The value specified for the soft heap limit
4022 ** is an upper bound on the total memory allocation for all threads. In
4023 ** version 3.5.0 there is no mechanism for limiting the heap usage for
4024 ** individual threads.
4025 **
4026 ** Requirements:
4027 ** [H16351] [H16352] [H16353] [H16354] [H16355] [H16358]
4028 */
4029 void sqlite3_soft_heap_limit(int);
4030
4031 /*
4032 ** CAPI3REF: Extract Metadata About A Column Of A Table {H12850} <S60300>
4033 **
4034 ** This routine returns metadata about a specific column of a specific
4035 ** database table accessible using the [database connection] handle
4036 ** passed as the first function argument.
4037 **
4038 ** The column is identified by the second, third and fourth parameters to
4039 ** this function. The second parameter is either the name of the database
4040 ** (i.e. "main", "temp" or an attached database) containing the specified
4041 ** table or NULL. If it is NULL, then all attached databases are searched
4042 ** for the table using the same algorithm used by the database engine to
4043 ** resolve unqualified table references.
4044 **
4045 ** The third and fourth parameters to this function are the table and column
4046 ** name of the desired column, respectively. Neither of these parameters
4047 ** may be NULL.
4048 **
4049 ** Metadata is returned by writing to the memory locations passed as the 5th
4050 ** and subsequent parameters to this function. Any of these arguments may be
4051 ** NULL, in which case the corresponding element of metadata is omitted.
4052 **
4053 ** <blockquote>
4054 ** <table border="1">
4055 ** <tr><th> Parameter <th> Output<br>Type <th> Description
4056 **
4057 ** <tr><td> 5th <td> const char* <td> Data type
4058 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
4059 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
4060 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
4061 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
4062 ** </table>
4063 ** </blockquote>
4064 **
4065 ** The memory pointed to by the character pointers returned for the
4066 ** declaration type and collation sequence is valid only until the next
4067 ** call to any SQLite API function.
4068 **
4069 ** If the specified table is actually a view, an [error code] is returned.
4070 **
4071 ** If the specified column is "rowid", "oid" or "_rowid_" and an
4072 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
4073 ** parameters are set for the explicitly declared column. If there is no
4074 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
4075 ** parameters are set as follows:
4076 **
4077 ** <pre>
4078 ** data type: "INTEGER"
4079 ** collation sequence: "BINARY"
4080 ** not null: 0
4081 ** primary key: 1
4082 ** auto increment: 0
4083 ** </pre>
4084 **
4085 ** This function may load one or more schemas from database files. If an
4086 ** error occurs during this process, or if the requested table or column
4087 ** cannot be found, an [error code] is returned and an error message left
4088 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).
4089 **
4090 ** This API is only available if the library was compiled with the
4091 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
4092 */
4093 int sqlite3_table_column_metadata(
4094 sqlite3 *db, /* Connection handle */
4095 const char *zDbName, /* Database name or NULL */
4096 const char *zTableName, /* Table name */
4097 const char *zColumnName, /* Column name */
4098 char const **pzDataType, /* OUTPUT: Declared data type */
4099 char const **pzCollSeq, /* OUTPUT: Collation sequence name */
4100 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
4101 int *pPrimaryKey, /* OUTPUT: True if column part of PK */
4102 int *pAutoinc /* OUTPUT: True if column is auto-increment */
4103 );
4104
4105 /*
4106 ** CAPI3REF: Load An Extension {H12600} <S20500>
4107 **
4108 ** This interface loads an SQLite extension library from the named file.
4109 **
4110 ** {H12601} The sqlite3_load_extension() interface attempts to load an
4111 ** SQLite extension library contained in the file zFile.
4112 **
4113 ** {H12602} The entry point is zProc.
4114 **
4115 ** {H12603} zProc may be 0, in which case the name of the entry point
4116 ** defaults to "sqlite3_extension_init".
4117 **
4118 ** {H12604} The sqlite3_load_extension() interface shall return
4119 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
4120 **
4121 ** {H12605} If an error occurs and pzErrMsg is not 0, then the
4122 ** [sqlite3_load_extension()] interface shall attempt to
4123 ** fill *pzErrMsg with error message text stored in memory
4124 ** obtained from [sqlite3_malloc()]. {END} The calling function
4125 ** should free this memory by calling [sqlite3_free()].
4126 **
4127 ** {H12606} Extension loading must be enabled using
4128 ** [sqlite3_enable_load_extension()] prior to calling this API,
4129 ** otherwise an error will be returned.
4130 */
4131 int sqlite3_load_extension(
4132 sqlite3 *db, /* Load the extension into this database connection */
4133 const char *zFile, /* Name of the shared library containing extension */
4134 const char *zProc, /* Entry point. Derived from zFile if 0 */
4135 char **pzErrMsg /* Put error message here if not 0 */
4136 );
4137
4138 /*
4139 ** CAPI3REF: Enable Or Disable Extension Loading {H12620} <S20500>
4140 **
4141 ** So as not to open security holes in older applications that are
4142 ** unprepared to deal with extension loading, and as a means of disabling
4143 ** extension loading while evaluating user-entered SQL, the following API
4144 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
4145 **
4146 ** Extension loading is off by default. See ticket #1863.
4147 **
4148 ** {H12621} Call the sqlite3_enable_load_extension() routine with onoff==1
4149 ** to turn extension loading on and call it with onoff==0 to turn
4150 ** it back off again.
4151 **
4152 ** {H12622} Extension loading is off by default.
4153 */
4154 int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
4155
4156 /*
4157 ** CAPI3REF: Automatically Load An Extensions {H12640} <S20500>
4158 **
4159 ** This API can be invoked at program startup in order to register
4160 ** one or more statically linked extensions that will be available
4161 ** to all new [database connections]. {END}
4162 **
4163 ** This routine stores a pointer to the extension in an array that is
4164 ** obtained from [sqlite3_malloc()]. If you run a memory leak checker
4165 ** on your program and it reports a leak because of this array, invoke
4166 ** [sqlite3_reset_auto_extension()] prior to shutdown to free the memory.
4167 **
4168 ** {H12641} This function registers an extension entry point that is
4169 ** automatically invoked whenever a new [database connection]
4170 ** is opened using [sqlite3_open()], [sqlite3_open16()],
4171 ** or [sqlite3_open_v2()].
4172 **
4173 ** {H12642} Duplicate extensions are detected so calling this routine
4174 ** multiple times with the same extension is harmless.
4175 **
4176 ** {H12643} This routine stores a pointer to the extension in an array
4177 ** that is obtained from [sqlite3_malloc()].
4178 **
4179 ** {H12644} Automatic extensions apply across all threads.
4180 */
4181 int sqlite3_auto_extension(void (*xEntryPoint)(void));
4182
4183 /*
4184 ** CAPI3REF: Reset Automatic Extension Loading {H12660} <S20500>
4185 **
4186 ** This function disables all previously registered automatic
4187 ** extensions. {END} It undoes the effect of all prior
4188 ** [sqlite3_auto_extension()] calls.
4189 **
4190 ** {H12661} This function disables all previously registered
4191 ** automatic extensions.
4192 **
4193 ** {H12662} This function disables automatic extensions in all threads.
4194 */
4195 void sqlite3_reset_auto_extension(void);
4196
4197 /*
4198 ****** EXPERIMENTAL - subject to change without notice **************
4199 **
4200 ** The interface to the virtual-table mechanism is currently considered
4201 ** to be experimental. The interface might change in incompatible ways.
4202 ** If this is a problem for you, do not use the interface at this time.
4203 **
4204 ** When the virtual-table mechanism stabilizes, we will declare the
4205 ** interface fixed, support it indefinitely, and remove this comment.
4206 */
4207
4208 /*
4209 ** Structures used by the virtual table interface
4210 */
4211 typedef struct sqlite3_vtab sqlite3_vtab;
4212 typedef struct sqlite3_index_info sqlite3_index_info;
4213 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
4214 typedef struct sqlite3_module sqlite3_module;
4215
4216 /*
4217 ** CAPI3REF: Virtual Table Object {H18000} <S20400>
4218 ** KEYWORDS: sqlite3_module {virtual table module}
4219 ** EXPERIMENTAL
4220 **
4221 ** This structure, sometimes called a a "virtual table module",
4222 ** defines the implementation of a [virtual tables].
4223 ** This structure consists mostly of methods for the module.
4224 **
4225 ** A virtual table module is created by filling in a persistent
4226 ** instance of this structure and passing a pointer to that instance
4227 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
4228 ** The registration remains valid until it is replaced by a different
4229 ** module or until the [database connection] closes. The content
4230 ** of this structure must not change while it is registered with
4231 ** any database connection.
4232 */
4233 struct sqlite3_module {
4234 int iVersion;
4235 int (*xCreate)(sqlite3*, void *pAux,
4236 int argc, const char *const*argv,
4237 sqlite3_vtab **ppVTab, char**);
4238 int (*xConnect)(sqlite3*, void *pAux,
4239 int argc, const char *const*argv,
4240 sqlite3_vtab **ppVTab, char**);
4241 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
4242 int (*xDisconnect)(sqlite3_vtab *pVTab);
4243 int (*xDestroy)(sqlite3_vtab *pVTab);
4244 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
4245 int (*xClose)(sqlite3_vtab_cursor*);
4246 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
4247 int argc, sqlite3_value **argv);
4248 int (*xNext)(sqlite3_vtab_cursor*);
4249 int (*xEof)(sqlite3_vtab_cursor*);
4250 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
4251 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
4252 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
4253 int (*xBegin)(sqlite3_vtab *pVTab);
4254 int (*xSync)(sqlite3_vtab *pVTab);
4255 int (*xCommit)(sqlite3_vtab *pVTab);
4256 int (*xRollback)(sqlite3_vtab *pVTab);
4257 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
4258 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
4259 void **ppArg);
4260 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
4261 };
4262
4263 /*
4264 ** CAPI3REF: Virtual Table Indexing Information {H18100} <S20400>
4265 ** KEYWORDS: sqlite3_index_info
4266 ** EXPERIMENTAL
4267 **
4268 ** The sqlite3_index_info structure and its substructures is used to
4269 ** pass information into and receive the reply from the [xBestIndex]
4270 ** method of a [virtual table module]. The fields under **Inputs** are the
4271 ** inputs to xBestIndex and are read-only. xBestIndex inserts its
4272 ** results into the **Outputs** fields.
4273 **
4274 ** The aConstraint[] array records WHERE clause constraints of the form:
4275 **
4276 ** <pre>column OP expr</pre>
4277 **
4278 ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=. The particular operator is
4279 ** stored in aConstraint[].op. The index of the column is stored in
4280 ** aConstraint[].iColumn. aConstraint[].usable is TRUE if the
4281 ** expr on the right-hand side can be evaluated (and thus the constraint
4282 ** is usable) and false if it cannot.
4283 **
4284 ** The optimizer automatically inverts terms of the form "expr OP column"
4285 ** and makes other simplifications to the WHERE clause in an attempt to
4286 ** get as many WHERE clause terms into the form shown above as possible.
4287 ** The aConstraint[] array only reports WHERE clause terms in the correct
4288 ** form that refer to the particular virtual table being queried.
4289 **
4290 ** Information about the ORDER BY clause is stored in aOrderBy[].
4291 ** Each term of aOrderBy records a column of the ORDER BY clause.
4292 **
4293 ** The [xBestIndex] method must fill aConstraintUsage[] with information
4294 ** about what parameters to pass to xFilter. If argvIndex>0 then
4295 ** the right-hand side of the corresponding aConstraint[] is evaluated
4296 ** and becomes the argvIndex-th entry in argv. If aConstraintUsage[].omit
4297 ** is true, then the constraint is assumed to be fully handled by the
4298 ** virtual table and is not checked again by SQLite.
4299 **
4300 ** The idxNum and idxPtr values are recorded and passed into the
4301 ** [xFilter] method.
4302 ** [sqlite3_free()] is used to free idxPtr if and only iff
4303 ** needToFreeIdxPtr is true.
4304 **
4305 ** The orderByConsumed means that output from [xFilter]/[xNext] will occur in
4306 ** the correct order to satisfy the ORDER BY clause so that no separate
4307 ** sorting step is required.
4308 **
4309 ** The estimatedCost value is an estimate of the cost of doing the
4310 ** particular lookup. A full scan of a table with N entries should have
4311 ** a cost of N. A binary search of a table of N entries should have a
4312 ** cost of approximately log(N).
4313 */
4314 struct sqlite3_index_info {
4315 /* Inputs */
4316 int nConstraint; /* Number of entries in aConstraint */
4317 struct sqlite3_index_constraint {
4318 int iColumn; /* Column on left-hand side of constraint */
4319 unsigned char op; /* Constraint operator */
4320 unsigned char usable; /* True if this constraint is usable */
4321 int iTermOffset; /* Used internally - xBestIndex should ignore */
4322 } *aConstraint; /* Table of WHERE clause constraints */
4323 int nOrderBy; /* Number of terms in the ORDER BY clause */
4324 struct sqlite3_index_orderby {
4325 int iColumn; /* Column number */
4326 unsigned char desc; /* True for DESC. False for ASC. */
4327 } *aOrderBy; /* The ORDER BY clause */
4328 /* Outputs */
4329 struct sqlite3_index_constraint_usage {
4330 int argvIndex; /* if >0, constraint is part of argv to xFilter */
4331 unsigned char omit; /* Do not code a test for this constraint */
4332 } *aConstraintUsage;
4333 int idxNum; /* Number used to identify the index */
4334 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
4335 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
4336 int orderByConsumed; /* True if output is already ordered */
4337 double estimatedCost; /* Estimated cost of using this index */
4338 };
4339 #define SQLITE_INDEX_CONSTRAINT_EQ 2
4340 #define SQLITE_INDEX_CONSTRAINT_GT 4
4341 #define SQLITE_INDEX_CONSTRAINT_LE 8
4342 #define SQLITE_INDEX_CONSTRAINT_LT 16
4343 #define SQLITE_INDEX_CONSTRAINT_GE 32
4344 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
4345
4346 /*
4347 ** CAPI3REF: Register A Virtual Table Implementation {H18200} <S20400>
4348 ** EXPERIMENTAL
4349 **
4350 ** This routine is used to register a new [virtual table module] name.
4351 ** Module names must be registered before
4352 ** creating a new [virtual table] using the module, or before using a
4353 ** preexisting [virtual table] for the module.
4354 **
4355 ** The module name is registered on the [database connection] specified
4356 ** by the first parameter. The name of the module is given by the
4357 ** second parameter. The third parameter is a pointer to
4358 ** the implementation of the [virtual table module]. The fourth
4359 ** parameter is an arbitrary client data pointer that is passed through
4360 ** into the [xCreate] and [xConnect] methods of the virtual table module
4361 ** when a new virtual table is be being created or reinitialized.
4362 **
4363 ** This interface has exactly the same effect as calling
4364 ** [sqlite3_create_module_v2()] with a NULL client data destructor.
4365 */
4366 SQLITE_EXPERIMENTAL int sqlite3_create_module(
4367 sqlite3 *db, /* SQLite connection to register module with */
4368 const char *zName, /* Name of the module */
4369 const sqlite3_module *p, /* Methods for the module */
4370 void *pClientData /* Client data for xCreate/xConnect */
4371 );
4372
4373 /*
4374 ** CAPI3REF: Register A Virtual Table Implementation {H18210} <S20400>
4375 ** EXPERIMENTAL
4376 **
4377 ** This routine is identical to the [sqlite3_create_module()] method,
4378 ** except that it has an extra parameter to specify
4379 ** a destructor function for the client data pointer. SQLite will
4380 ** invoke the destructor function (if it is not NULL) when SQLite
4381 ** no longer needs the pClientData pointer.
4382 */
4383 SQLITE_EXPERIMENTAL int sqlite3_create_module_v2(
4384 sqlite3 *db, /* SQLite connection to register module with */
4385 const char *zName, /* Name of the module */
4386 const sqlite3_module *p, /* Methods for the module */
4387 void *pClientData, /* Client data for xCreate/xConnect */
4388 void(*xDestroy)(void*) /* Module destructor function */
4389 );
4390
4391 /*
4392 ** CAPI3REF: Virtual Table Instance Object {H18010} <S20400>
4393 ** KEYWORDS: sqlite3_vtab
4394 ** EXPERIMENTAL
4395 **
4396 ** Every [virtual table module] implementation uses a subclass
4397 ** of the following structure to describe a particular instance
4398 ** of the [virtual table]. Each subclass will
4399 ** be tailored to the specific needs of the module implementation.
4400 ** The purpose of this superclass is to define certain fields that are
4401 ** common to all module implementations.
4402 **
4403 ** Virtual tables methods can set an error message by assigning a
4404 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
4405 ** take care that any prior string is freed by a call to [sqlite3_free()]
4406 ** prior to assigning a new string to zErrMsg. After the error message
4407 ** is delivered up to the client application, the string will be automatically
4408 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
4409 */
4410 struct sqlite3_vtab {
4411 const sqlite3_module *pModule; /* The module for this virtual table */
4412 int nRef; /* NO LONGER USED */
4413 char *zErrMsg; /* Error message from sqlite3_mprintf() */
4414 /* Virtual table implementations will typically add additional fields */
4415 };
4416
4417 /*
4418 ** CAPI3REF: Virtual Table Cursor Object {H18020} <S20400>
4419 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
4420 ** EXPERIMENTAL
4421 **
4422 ** Every [virtual table module] implementation uses a subclass of the
4423 ** following structure to describe cursors that point into the
4424 ** [virtual table] and are used
4425 ** to loop through the virtual table. Cursors are created using the
4426 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
4427 ** by the [sqlite3_module.xClose | xClose] method. Cussors are used
4428 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
4429 ** of the module. Each module implementation will define
4430 ** the content of a cursor structure to suit its own needs.
4431 **
4432 ** This superclass exists in order to define fields of the cursor that
4433 ** are common to all implementations.
4434 */
4435 struct sqlite3_vtab_cursor {
4436 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
4437 /* Virtual table implementations will typically add additional fields */
4438 };
4439
4440 /*
4441 ** CAPI3REF: Declare The Schema Of A Virtual Table {H18280} <S20400>
4442 ** EXPERIMENTAL
4443 **
4444 ** The [xCreate] and [xConnect] methods of a
4445 ** [virtual table module] call this interface
4446 ** to declare the format (the names and datatypes of the columns) of
4447 ** the virtual tables they implement.
4448 */
4449 SQLITE_EXPERIMENTAL int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
4450
4451 /*
4452 ** CAPI3REF: Overload A Function For A Virtual Table {H18300} <S20400>
4453 ** EXPERIMENTAL
4454 **
4455 ** Virtual tables can provide alternative implementations of functions
4456 ** using the [xFindFunction] method of the [virtual table module].
4457 ** But global versions of those functions
4458 ** must exist in order to be overloaded.
4459 **
4460 ** This API makes sure a global version of a function with a particular
4461 ** name and number of parameters exists. If no such function exists
4462 ** before this API is called, a new function is created. The implementation
4463 ** of the new function always causes an exception to be thrown. So
4464 ** the new function is not good for anything by itself. Its only
4465 ** purpose is to be a placeholder function that can be overloaded
4466 ** by a [virtual table].
4467 */
4468 SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const char *zFuncNam e, int nArg);
4469
4470 /*
4471 ** The interface to the virtual-table mechanism defined above (back up
4472 ** to a comment remarkably similar to this one) is currently considered
4473 ** to be experimental. The interface might change in incompatible ways.
4474 ** If this is a problem for you, do not use the interface at this time.
4475 **
4476 ** When the virtual-table mechanism stabilizes, we will declare the
4477 ** interface fixed, support it indefinitely, and remove this comment.
4478 **
4479 ****** EXPERIMENTAL - subject to change without notice **************
4480 */
4481
4482 /*
4483 ** CAPI3REF: A Handle To An Open BLOB {H17800} <S30230>
4484 ** KEYWORDS: {BLOB handle} {BLOB handles}
4485 **
4486 ** An instance of this object represents an open BLOB on which
4487 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
4488 ** Objects of this type are created by [sqlite3_blob_open()]
4489 ** and destroyed by [sqlite3_blob_close()].
4490 ** The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
4491 ** can be used to read or write small subsections of the BLOB.
4492 ** The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
4493 */
4494 typedef struct sqlite3_blob sqlite3_blob;
4495
4496 /*
4497 ** CAPI3REF: Open A BLOB For Incremental I/O {H17810} <S30230>
4498 **
4499 ** This interfaces opens a [BLOB handle | handle] to the BLOB located
4500 ** in row iRow, column zColumn, table zTable in database zDb;
4501 ** in other words, the same BLOB that would be selected by:
4502 **
4503 ** <pre>
4504 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
4505 ** </pre> {END}
4506 **
4507 ** If the flags parameter is non-zero, then the BLOB is opened for read
4508 ** and write access. If it is zero, the BLOB is opened for read access.
4509 **
4510 ** Note that the database name is not the filename that contains
4511 ** the database but rather the symbolic name of the database that
4512 ** is assigned when the database is connected using [ATTACH].
4513 ** For the main database file, the database name is "main".
4514 ** For TEMP tables, the database name is "temp".
4515 **
4516 ** On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
4517 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
4518 ** to be a null pointer.
4519 ** This function sets the [database connection] error code and message
4520 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
4521 ** functions. Note that the *ppBlob variable is always initialized in a
4522 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
4523 ** regardless of the success or failure of this routine.
4524 **
4525 ** If the row that a BLOB handle points to is modified by an
4526 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
4527 ** then the BLOB handle is marked as "expired".
4528 ** This is true if any column of the row is changed, even a column
4529 ** other than the one the BLOB handle is open on.
4530 ** Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
4531 ** a expired BLOB handle fail with an return code of [SQLITE_ABORT].
4532 ** Changes written into a BLOB prior to the BLOB expiring are not
4533 ** rollback by the expiration of the BLOB. Such changes will eventually
4534 ** commit if the transaction continues to completion.
4535 **
4536 ** Use the [sqlite3_blob_bytes()] interface to determine the size of
4537 ** the opened blob. The size of a blob may not be changed by this
4538 ** interface. Use the [UPDATE] SQL command to change the size of a
4539 ** blob.
4540 **
4541 ** The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
4542 ** and the built-in [zeroblob] SQL function can be used, if desired,
4543 ** to create an empty, zero-filled blob in which to read or write using
4544 ** this interface.
4545 **
4546 ** To avoid a resource leak, every open [BLOB handle] should eventually
4547 ** be released by a call to [sqlite3_blob_close()].
4548 **
4549 ** Requirements:
4550 ** [H17813] [H17814] [H17816] [H17819] [H17821] [H17824]
4551 */
4552 int sqlite3_blob_open(
4553 sqlite3*,
4554 const char *zDb,
4555 const char *zTable,
4556 const char *zColumn,
4557 sqlite3_int64 iRow,
4558 int flags,
4559 sqlite3_blob **ppBlob
4560 );
4561
4562 /*
4563 ** CAPI3REF: Close A BLOB Handle {H17830} <S30230>
4564 **
4565 ** Closes an open [BLOB handle].
4566 **
4567 ** Closing a BLOB shall cause the current transaction to commit
4568 ** if there are no other BLOBs, no pending prepared statements, and the
4569 ** database connection is in [autocommit mode].
4570 ** If any writes were made to the BLOB, they might be held in cache
4571 ** until the close operation if they will fit.
4572 **
4573 ** Closing the BLOB often forces the changes
4574 ** out to disk and so if any I/O errors occur, they will likely occur
4575 ** at the time when the BLOB is closed. Any errors that occur during
4576 ** closing are reported as a non-zero return value.
4577 **
4578 ** The BLOB is closed unconditionally. Even if this routine returns
4579 ** an error code, the BLOB is still closed.
4580 **
4581 ** Calling this routine with a null pointer (which as would be returned
4582 ** by failed call to [sqlite3_blob_open()]) is a harmless no-op.
4583 **
4584 ** Requirements:
4585 ** [H17833] [H17836] [H17839]
4586 */
4587 int sqlite3_blob_close(sqlite3_blob *);
4588
4589 /*
4590 ** CAPI3REF: Return The Size Of An Open BLOB {H17840} <S30230>
4591 **
4592 ** Returns the size in bytes of the BLOB accessible via the
4593 ** successfully opened [BLOB handle] in its only argument. The
4594 ** incremental blob I/O routines can only read or overwriting existing
4595 ** blob content; they cannot change the size of a blob.
4596 **
4597 ** This routine only works on a [BLOB handle] which has been created
4598 ** by a prior successful call to [sqlite3_blob_open()] and which has not
4599 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
4600 ** to this routine results in undefined and probably undesirable behavior.
4601 **
4602 ** Requirements:
4603 ** [H17843]
4604 */
4605 int sqlite3_blob_bytes(sqlite3_blob *);
4606
4607 /*
4608 ** CAPI3REF: Read Data From A BLOB Incrementally {H17850} <S30230>
4609 **
4610 ** This function is used to read data from an open [BLOB handle] into a
4611 ** caller-supplied buffer. N bytes of data are copied into buffer Z
4612 ** from the open BLOB, starting at offset iOffset.
4613 **
4614 ** If offset iOffset is less than N bytes from the end of the BLOB,
4615 ** [SQLITE_ERROR] is returned and no data is read. If N or iOffset is
4616 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
4617 ** The size of the blob (and hence the maximum value of N+iOffset)
4618 ** can be determined using the [sqlite3_blob_bytes()] interface.
4619 **
4620 ** An attempt to read from an expired [BLOB handle] fails with an
4621 ** error code of [SQLITE_ABORT].
4622 **
4623 ** On success, SQLITE_OK is returned.
4624 ** Otherwise, an [error code] or an [extended error code] is returned.
4625 **
4626 ** This routine only works on a [BLOB handle] which has been created
4627 ** by a prior successful call to [sqlite3_blob_open()] and which has not
4628 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
4629 ** to this routine results in undefined and probably undesirable behavior.
4630 **
4631 ** See also: [sqlite3_blob_write()].
4632 **
4633 ** Requirements:
4634 ** [H17853] [H17856] [H17859] [H17862] [H17863] [H17865] [H17868]
4635 */
4636 int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
4637
4638 /*
4639 ** CAPI3REF: Write Data Into A BLOB Incrementally {H17870} <S30230>
4640 **
4641 ** This function is used to write data into an open [BLOB handle] from a
4642 ** caller-supplied buffer. N bytes of data are copied from the buffer Z
4643 ** into the open BLOB, starting at offset iOffset.
4644 **
4645 ** If the [BLOB handle] passed as the first argument was not opened for
4646 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
4647 ** this function returns [SQLITE_READONLY].
4648 **
4649 ** This function may only modify the contents of the BLOB; it is
4650 ** not possible to increase the size of a BLOB using this API.
4651 ** If offset iOffset is less than N bytes from the end of the BLOB,
4652 ** [SQLITE_ERROR] is returned and no data is written. If N is
4653 ** less than zero [SQLITE_ERROR] is returned and no data is written.
4654 ** The size of the BLOB (and hence the maximum value of N+iOffset)
4655 ** can be determined using the [sqlite3_blob_bytes()] interface.
4656 **
4657 ** An attempt to write to an expired [BLOB handle] fails with an
4658 ** error code of [SQLITE_ABORT]. Writes to the BLOB that occurred
4659 ** before the [BLOB handle] expired are not rolled back by the
4660 ** expiration of the handle, though of course those changes might
4661 ** have been overwritten by the statement that expired the BLOB handle
4662 ** or by other independent statements.
4663 **
4664 ** On success, SQLITE_OK is returned.
4665 ** Otherwise, an [error code] or an [extended error code] is returned.
4666 **
4667 ** This routine only works on a [BLOB handle] which has been created
4668 ** by a prior successful call to [sqlite3_blob_open()] and which has not
4669 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
4670 ** to this routine results in undefined and probably undesirable behavior.
4671 **
4672 ** See also: [sqlite3_blob_read()].
4673 **
4674 ** Requirements:
4675 ** [H17873] [H17874] [H17875] [H17876] [H17877] [H17879] [H17882] [H17885]
4676 ** [H17888]
4677 */
4678 int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
4679
4680 /* Begin preload-cache.patch for Chromium */
4681 /*
4682 ** Preload the databases into the pager cache, up to the maximum size of the
4683 ** pager cache.
4684 **
4685 ** For a database to be loaded successfully, the pager must be active. That is,
4686 ** there must be an open statement on that database. See sqlite3pager_loadall
4687 **
4688 ** There might be many databases attached to the given connection. We iterate
4689 ** them all and try to load them. If none are loadable successfully, we return
4690 ** an error. Otherwise, we return OK.
4691 */
4692 int sqlite3Preload(sqlite3 *db);
4693 /* End preload-cache.patch for Chromium */
4694
4695 /*
4696 ** CAPI3REF: Virtual File System Objects {H11200} <S20100>
4697 **
4698 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
4699 ** that SQLite uses to interact
4700 ** with the underlying operating system. Most SQLite builds come with a
4701 ** single default VFS that is appropriate for the host computer.
4702 ** New VFSes can be registered and existing VFSes can be unregistered.
4703 ** The following interfaces are provided.
4704 **
4705 ** The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
4706 ** Names are case sensitive.
4707 ** Names are zero-terminated UTF-8 strings.
4708 ** If there is no match, a NULL pointer is returned.
4709 ** If zVfsName is NULL then the default VFS is returned.
4710 **
4711 ** New VFSes are registered with sqlite3_vfs_register().
4712 ** Each new VFS becomes the default VFS if the makeDflt flag is set.
4713 ** The same VFS can be registered multiple times without injury.
4714 ** To make an existing VFS into the default VFS, register it again
4715 ** with the makeDflt flag set. If two different VFSes with the
4716 ** same name are registered, the behavior is undefined. If a
4717 ** VFS is registered with a name that is NULL or an empty string,
4718 ** then the behavior is undefined.
4719 **
4720 ** Unregister a VFS with the sqlite3_vfs_unregister() interface.
4721 ** If the default VFS is unregistered, another VFS is chosen as
4722 ** the default. The choice for the new VFS is arbitrary.
4723 **
4724 ** Requirements:
4725 ** [H11203] [H11206] [H11209] [H11212] [H11215] [H11218]
4726 */
4727 sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
4728 int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
4729 int sqlite3_vfs_unregister(sqlite3_vfs*);
4730
4731 /*
4732 ** CAPI3REF: Mutexes {H17000} <S20000>
4733 **
4734 ** The SQLite core uses these routines for thread
4735 ** synchronization. Though they are intended for internal
4736 ** use by SQLite, code that links against SQLite is
4737 ** permitted to use any of these routines.
4738 **
4739 ** The SQLite source code contains multiple implementations
4740 ** of these mutex routines. An appropriate implementation
4741 ** is selected automatically at compile-time. The following
4742 ** implementations are available in the SQLite core:
4743 **
4744 ** <ul>
4745 ** <li> SQLITE_MUTEX_OS2
4746 ** <li> SQLITE_MUTEX_PTHREAD
4747 ** <li> SQLITE_MUTEX_W32
4748 ** <li> SQLITE_MUTEX_NOOP
4749 ** </ul>
4750 **
4751 ** The SQLITE_MUTEX_NOOP implementation is a set of routines
4752 ** that does no real locking and is appropriate for use in
4753 ** a single-threaded application. The SQLITE_MUTEX_OS2,
4754 ** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
4755 ** are appropriate for use on OS/2, Unix, and Windows.
4756 **
4757 ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
4758 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
4759 ** implementation is included with the library. In this case the
4760 ** application must supply a custom mutex implementation using the
4761 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
4762 ** before calling sqlite3_initialize() or any other public sqlite3_
4763 ** function that calls sqlite3_initialize().
4764 **
4765 ** {H17011} The sqlite3_mutex_alloc() routine allocates a new
4766 ** mutex and returns a pointer to it. {H17012} If it returns NULL
4767 ** that means that a mutex could not be allocated. {H17013} SQLite
4768 ** will unwind its stack and return an error. {H17014} The argument
4769 ** to sqlite3_mutex_alloc() is one of these integer constants:
4770 **
4771 ** <ul>
4772 ** <li> SQLITE_MUTEX_FAST
4773 ** <li> SQLITE_MUTEX_RECURSIVE
4774 ** <li> SQLITE_MUTEX_STATIC_MASTER
4775 ** <li> SQLITE_MUTEX_STATIC_MEM
4776 ** <li> SQLITE_MUTEX_STATIC_MEM2
4777 ** <li> SQLITE_MUTEX_STATIC_PRNG
4778 ** <li> SQLITE_MUTEX_STATIC_LRU
4779 ** <li> SQLITE_MUTEX_STATIC_LRU2
4780 ** </ul>
4781 **
4782 ** {H17015} The first two constants cause sqlite3_mutex_alloc() to create
4783 ** a new mutex. The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
4784 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used. {END}
4785 ** The mutex implementation does not need to make a distinction
4786 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
4787 ** not want to. {H17016} But SQLite will only request a recursive mutex in
4788 ** cases where it really needs one. {END} If a faster non-recursive mutex
4789 ** implementation is available on the host platform, the mutex subsystem
4790 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
4791 **
4792 ** {H17017} The other allowed parameters to sqlite3_mutex_alloc() each return
4793 ** a pointer to a static preexisting mutex. {END} Six static mutexes are
4794 ** used by the current version of SQLite. Future versions of SQLite
4795 ** may add additional static mutexes. Static mutexes are for internal
4796 ** use by SQLite only. Applications that use SQLite mutexes should
4797 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
4798 ** SQLITE_MUTEX_RECURSIVE.
4799 **
4800 ** {H17018} Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
4801 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
4802 ** returns a different mutex on every call. {H17034} But for the static
4803 ** mutex types, the same mutex is returned on every call that has
4804 ** the same type number.
4805 **
4806 ** {H17019} The sqlite3_mutex_free() routine deallocates a previously
4807 ** allocated dynamic mutex. {H17020} SQLite is careful to deallocate every
4808 ** dynamic mutex that it allocates. {A17021} The dynamic mutexes must not be in
4809 ** use when they are deallocated. {A17022} Attempting to deallocate a static
4810 ** mutex results in undefined behavior. {H17023} SQLite never deallocates
4811 ** a static mutex. {END}
4812 **
4813 ** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
4814 ** to enter a mutex. {H17024} If another thread is already within the mutex,
4815 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
4816 ** SQLITE_BUSY. {H17025} The sqlite3_mutex_try() interface returns [SQLITE_OK]
4817 ** upon successful entry. {H17026} Mutexes created using
4818 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
4819 ** {H17027} In such cases the,
4820 ** mutex must be exited an equal number of times before another thread
4821 ** can enter. {A17028} If the same thread tries to enter any other
4822 ** kind of mutex more than once, the behavior is undefined.
4823 ** {H17029} SQLite will never exhibit
4824 ** such behavior in its own use of mutexes.
4825 **
4826 ** Some systems (for example, Windows 95) do not support the operation
4827 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
4828 ** will always return SQLITE_BUSY. {H17030} The SQLite core only ever uses
4829 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.
4830 **
4831 ** {H17031} The sqlite3_mutex_leave() routine exits a mutex that was
4832 ** previously entered by the same thread. {A17032} The behavior
4833 ** is undefined if the mutex is not currently entered by the
4834 ** calling thread or is not currently allocated. {H17033} SQLite will
4835 ** never do either. {END}
4836 **
4837 ** If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
4838 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
4839 ** behave as no-ops.
4840 **
4841 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
4842 */
4843 sqlite3_mutex *sqlite3_mutex_alloc(int);
4844 void sqlite3_mutex_free(sqlite3_mutex*);
4845 void sqlite3_mutex_enter(sqlite3_mutex*);
4846 int sqlite3_mutex_try(sqlite3_mutex*);
4847 void sqlite3_mutex_leave(sqlite3_mutex*);
4848
4849 /*
4850 ** CAPI3REF: Mutex Methods Object {H17120} <S20130>
4851 ** EXPERIMENTAL
4852 **
4853 ** An instance of this structure defines the low-level routines
4854 ** used to allocate and use mutexes.
4855 **
4856 ** Usually, the default mutex implementations provided by SQLite are
4857 ** sufficient, however the user has the option of substituting a custom
4858 ** implementation for specialized deployments or systems for which SQLite
4859 ** does not provide a suitable implementation. In this case, the user
4860 ** creates and populates an instance of this structure to pass
4861 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
4862 ** Additionally, an instance of this structure can be used as an
4863 ** output variable when querying the system for the current mutex
4864 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
4865 **
4866 ** The xMutexInit method defined by this structure is invoked as
4867 ** part of system initialization by the sqlite3_initialize() function.
4868 ** {H17001} The xMutexInit routine shall be called by SQLite once for each
4869 ** effective call to [sqlite3_initialize()].
4870 **
4871 ** The xMutexEnd method defined by this structure is invoked as
4872 ** part of system shutdown by the sqlite3_shutdown() function. The
4873 ** implementation of this method is expected to release all outstanding
4874 ** resources obtained by the mutex methods implementation, especially
4875 ** those obtained by the xMutexInit method. {H17003} The xMutexEnd()
4876 ** interface shall be invoked once for each call to [sqlite3_shutdown()].
4877 **
4878 ** The remaining seven methods defined by this structure (xMutexAlloc,
4879 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
4880 ** xMutexNotheld) implement the following interfaces (respectively):
4881 **
4882 ** <ul>
4883 ** <li> [sqlite3_mutex_alloc()] </li>
4884 ** <li> [sqlite3_mutex_free()] </li>
4885 ** <li> [sqlite3_mutex_enter()] </li>
4886 ** <li> [sqlite3_mutex_try()] </li>
4887 ** <li> [sqlite3_mutex_leave()] </li>
4888 ** <li> [sqlite3_mutex_held()] </li>
4889 ** <li> [sqlite3_mutex_notheld()] </li>
4890 ** </ul>
4891 **
4892 ** The only difference is that the public sqlite3_XXX functions enumerated
4893 ** above silently ignore any invocations that pass a NULL pointer instead
4894 ** of a valid mutex handle. The implementations of the methods defined
4895 ** by this structure are not required to handle this case, the results
4896 ** of passing a NULL pointer instead of a valid mutex handle are undefined
4897 ** (i.e. it is acceptable to provide an implementation that segfaults if
4898 ** it is passed a NULL pointer).
4899 **
4900 ** The xMutexInit() method must be threadsafe. It must be harmless to
4901 ** invoke xMutexInit() mutiple times within the same process and without
4902 ** intervening calls to xMutexEnd(). Second and subsequent calls to
4903 ** xMutexInit() must be no-ops.
4904 **
4905 ** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
4906 ** and its associates). Similarly, xMutexAlloc() must not use SQLite memory
4907 ** allocation for a static mutex. However xMutexAlloc() may use SQLite
4908 ** memory allocation for a fast or recursive mutex.
4909 **
4910 ** SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
4911 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
4912 ** If xMutexInit fails in any way, it is expected to clean up after itself
4913 ** prior to returning.
4914 */
4915 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
4916 struct sqlite3_mutex_methods {
4917 int (*xMutexInit)(void);
4918 int (*xMutexEnd)(void);
4919 sqlite3_mutex *(*xMutexAlloc)(int);
4920 void (*xMutexFree)(sqlite3_mutex *);
4921 void (*xMutexEnter)(sqlite3_mutex *);
4922 int (*xMutexTry)(sqlite3_mutex *);
4923 void (*xMutexLeave)(sqlite3_mutex *);
4924 int (*xMutexHeld)(sqlite3_mutex *);
4925 int (*xMutexNotheld)(sqlite3_mutex *);
4926 };
4927
4928 /*
4929 ** CAPI3REF: Mutex Verification Routines {H17080} <S20130> <S30800>
4930 **
4931 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
4932 ** are intended for use inside assert() statements. {H17081} The SQLite core
4933 ** never uses these routines except inside an assert() and applications
4934 ** are advised to follow the lead of the core. {H17082} The core only
4935 ** provides implementations for these routines when it is compiled
4936 ** with the SQLITE_DEBUG flag. {A17087} External mutex implementations
4937 ** are only required to provide these routines if SQLITE_DEBUG is
4938 ** defined and if NDEBUG is not defined.
4939 **
4940 ** {H17083} These routines should return true if the mutex in their argument
4941 ** is held or not held, respectively, by the calling thread.
4942 **
4943 ** {X17084} The implementation is not required to provided versions of these
4944 ** routines that actually work. If the implementation does not provide working
4945 ** versions of these routines, it should at least provide stubs that always
4946 ** return true so that one does not get spurious assertion failures.
4947 **
4948 ** {H17085} If the argument to sqlite3_mutex_held() is a NULL pointer then
4949 ** the routine should return 1. {END} This seems counter-intuitive since
4950 ** clearly the mutex cannot be held if it does not exist. But the
4951 ** the reason the mutex does not exist is because the build is not
4952 ** using mutexes. And we do not want the assert() containing the
4953 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
4954 ** the appropriate thing to do. {H17086} The sqlite3_mutex_notheld()
4955 ** interface should also return 1 when given a NULL pointer.
4956 */
4957 int sqlite3_mutex_held(sqlite3_mutex*);
4958 int sqlite3_mutex_notheld(sqlite3_mutex*);
4959
4960 /*
4961 ** CAPI3REF: Mutex Types {H17001} <H17000>
4962 **
4963 ** The [sqlite3_mutex_alloc()] interface takes a single argument
4964 ** which is one of these integer constants.
4965 **
4966 ** The set of static mutexes may change from one SQLite release to the
4967 ** next. Applications that override the built-in mutex logic must be
4968 ** prepared to accommodate additional static mutexes.
4969 */
4970 #define SQLITE_MUTEX_FAST 0
4971 #define SQLITE_MUTEX_RECURSIVE 1
4972 #define SQLITE_MUTEX_STATIC_MASTER 2
4973 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
4974 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
4975 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
4976 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */
4977 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
4978 #define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */
4979
4980 /*
4981 ** CAPI3REF: Retrieve the mutex for a database connection {H17002} <H17000>
4982 **
4983 ** This interface returns a pointer the [sqlite3_mutex] object that
4984 ** serializes access to the [database connection] given in the argument
4985 ** when the [threading mode] is Serialized.
4986 ** If the [threading mode] is Single-thread or Multi-thread then this
4987 ** routine returns a NULL pointer.
4988 */
4989 sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
4990
4991 /*
4992 ** CAPI3REF: Low-Level Control Of Database Files {H11300} <S30800>
4993 **
4994 ** {H11301} The [sqlite3_file_control()] interface makes a direct call to the
4995 ** xFileControl method for the [sqlite3_io_methods] object associated
4996 ** with a particular database identified by the second argument. {H11302} The
4997 ** name of the database is the name assigned to the database by the
4998 ** <a href="lang_attach.html">ATTACH</a> SQL command that opened the
4999 ** database. {H11303} To control the main database file, use the name "main"
5000 ** or a NULL pointer. {H11304} The third and fourth parameters to this routine
5001 ** are passed directly through to the second and third parameters of
5002 ** the xFileControl method. {H11305} The return value of the xFileControl
5003 ** method becomes the return value of this routine.
5004 **
5005 ** {H11306} If the second parameter (zDbName) does not match the name of any
5006 ** open database file, then SQLITE_ERROR is returned. {H11307} This error
5007 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
5008 ** or [sqlite3_errmsg()]. {A11308} The underlying xFileControl method might
5009 ** also return SQLITE_ERROR. {A11309} There is no way to distinguish between
5010 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
5011 ** xFileControl method. {END}
5012 **
5013 ** See also: [SQLITE_FCNTL_LOCKSTATE]
5014 */
5015 int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
5016
5017 /*
5018 ** CAPI3REF: Testing Interface {H11400} <S30800>
5019 **
5020 ** The sqlite3_test_control() interface is used to read out internal
5021 ** state of SQLite and to inject faults into SQLite for testing
5022 ** purposes. The first parameter is an operation code that determines
5023 ** the number, meaning, and operation of all subsequent parameters.
5024 **
5025 ** This interface is not for use by applications. It exists solely
5026 ** for verifying the correct operation of the SQLite library. Depending
5027 ** on how the SQLite library is compiled, this interface might not exist.
5028 **
5029 ** The details of the operation codes, their meanings, the parameters
5030 ** they take, and what they do are all subject to change without notice.
5031 ** Unlike most of the SQLite API, this function is not guaranteed to
5032 ** operate consistently from one release to the next.
5033 */
5034 int sqlite3_test_control(int op, ...);
5035
5036 /*
5037 ** CAPI3REF: Testing Interface Operation Codes {H11410} <H11400>
5038 **
5039 ** These constants are the valid operation code parameters used
5040 ** as the first argument to [sqlite3_test_control()].
5041 **
5042 ** These parameters and their meanings are subject to change
5043 ** without notice. These values are for testing purposes only.
5044 ** Applications should not use any of these parameters or the
5045 ** [sqlite3_test_control()] interface.
5046 */
5047 #define SQLITE_TESTCTRL_PRNG_SAVE 5
5048 #define SQLITE_TESTCTRL_PRNG_RESTORE 6
5049 #define SQLITE_TESTCTRL_PRNG_RESET 7
5050 #define SQLITE_TESTCTRL_BITVEC_TEST 8
5051 #define SQLITE_TESTCTRL_FAULT_INSTALL 9
5052 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
5053 #define SQLITE_TESTCTRL_PENDING_BYTE 11
5054 #define SQLITE_TESTCTRL_ASSERT 12
5055 #define SQLITE_TESTCTRL_ALWAYS 13
5056 #define SQLITE_TESTCTRL_RESERVE 14
5057
5058 /*
5059 ** CAPI3REF: SQLite Runtime Status {H17200} <S60200>
5060 ** EXPERIMENTAL
5061 **
5062 ** This interface is used to retrieve runtime status information
5063 ** about the preformance of SQLite, and optionally to reset various
5064 ** highwater marks. The first argument is an integer code for
5065 ** the specific parameter to measure. Recognized integer codes
5066 ** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].
5067 ** The current value of the parameter is returned into *pCurrent.
5068 ** The highest recorded value is returned in *pHighwater. If the
5069 ** resetFlag is true, then the highest record value is reset after
5070 ** *pHighwater is written. Some parameters do not record the highest
5071 ** value. For those parameters
5072 ** nothing is written into *pHighwater and the resetFlag is ignored.
5073 ** Other parameters record only the highwater mark and not the current
5074 ** value. For these latter parameters nothing is written into *pCurrent.
5075 **
5076 ** This routine returns SQLITE_OK on success and a non-zero
5077 ** [error code] on failure.
5078 **
5079 ** This routine is threadsafe but is not atomic. This routine can be
5080 ** called while other threads are running the same or different SQLite
5081 ** interfaces. However the values returned in *pCurrent and
5082 ** *pHighwater reflect the status of SQLite at different points in time
5083 ** and it is possible that another thread might change the parameter
5084 ** in between the times when *pCurrent and *pHighwater are written.
5085 **
5086 ** See also: [sqlite3_db_status()]
5087 */
5088 SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, i nt resetFlag);
5089
5090
5091 /*
5092 ** CAPI3REF: Status Parameters {H17250} <H17200>
5093 ** EXPERIMENTAL
5094 **
5095 ** These integer constants designate various run-time status parameters
5096 ** that can be returned by [sqlite3_status()].
5097 **
5098 ** <dl>
5099 ** <dt>SQLITE_STATUS_MEMORY_USED</dt>
5100 ** <dd>This parameter is the current amount of memory checked out
5101 ** using [sqlite3_malloc()], either directly or indirectly. The
5102 ** figure includes calls made to [sqlite3_malloc()] by the application
5103 ** and internal memory usage by the SQLite library. Scratch memory
5104 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
5105 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
5106 ** this parameter. The amount returned is the sum of the allocation
5107 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>
5108 **
5109 ** <dt>SQLITE_STATUS_MALLOC_SIZE</dt>
5110 ** <dd>This parameter records the largest memory allocation request
5111 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
5112 ** internal equivalents). Only the value returned in the
5113 ** *pHighwater parameter to [sqlite3_status()] is of interest.
5114 ** The value written into the *pCurrent parameter is undefined.</dd>
5115 **
5116 ** <dt>SQLITE_STATUS_PAGECACHE_USED</dt>
5117 ** <dd>This parameter returns the number of pages used out of the
5118 ** [pagecache memory allocator] that was configured using
5119 ** [SQLITE_CONFIG_PAGECACHE]. The
5120 ** value returned is in pages, not in bytes.</dd>
5121 **
5122 ** <dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
5123 ** <dd>This parameter returns the number of bytes of page cache
5124 ** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE]
5125 ** buffer and where forced to overflow to [sqlite3_malloc()]. The
5126 ** returned value includes allocations that overflowed because they
5127 ** where too large (they were larger than the "sz" parameter to
5128 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
5129 ** no space was left in the page cache.</dd>
5130 **
5131 ** <dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
5132 ** <dd>This parameter records the largest memory allocation request
5133 ** handed to [pagecache memory allocator]. Only the value returned in the
5134 ** *pHighwater parameter to [sqlite3_status()] is of interest.
5135 ** The value written into the *pCurrent parameter is undefined.</dd>
5136 **
5137 ** <dt>SQLITE_STATUS_SCRATCH_USED</dt>
5138 ** <dd>This parameter returns the number of allocations used out of the
5139 ** [scratch memory allocator] configured using
5140 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not
5141 ** in bytes. Since a single thread may only have one scratch allocation
5142 ** outstanding at time, this parameter also reports the number of threads
5143 ** using scratch memory at the same time.</dd>
5144 **
5145 ** <dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
5146 ** <dd>This parameter returns the number of bytes of scratch memory
5147 ** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH]
5148 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values
5149 ** returned include overflows because the requested allocation was too
5150 ** larger (that is, because the requested allocation was larger than the
5151 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
5152 ** slots were available.
5153 ** </dd>
5154 **
5155 ** <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
5156 ** <dd>This parameter records the largest memory allocation request
5157 ** handed to [scratch memory allocator]. Only the value returned in the
5158 ** *pHighwater parameter to [sqlite3_status()] is of interest.
5159 ** The value written into the *pCurrent parameter is undefined.</dd>
5160 **
5161 ** <dt>SQLITE_STATUS_PARSER_STACK</dt>
5162 ** <dd>This parameter records the deepest parser stack. It is only
5163 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>
5164 ** </dl>
5165 **
5166 ** New status parameters may be added from time to time.
5167 */
5168 #define SQLITE_STATUS_MEMORY_USED 0
5169 #define SQLITE_STATUS_PAGECACHE_USED 1
5170 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
5171 #define SQLITE_STATUS_SCRATCH_USED 3
5172 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4
5173 #define SQLITE_STATUS_MALLOC_SIZE 5
5174 #define SQLITE_STATUS_PARSER_STACK 6
5175 #define SQLITE_STATUS_PAGECACHE_SIZE 7
5176 #define SQLITE_STATUS_SCRATCH_SIZE 8
5177
5178 /*
5179 ** CAPI3REF: Database Connection Status {H17500} <S60200>
5180 ** EXPERIMENTAL
5181 **
5182 ** This interface is used to retrieve runtime status information
5183 ** about a single [database connection]. The first argument is the
5184 ** database connection object to be interrogated. The second argument
5185 ** is the parameter to interrogate. Currently, the only allowed value
5186 ** for the second parameter is [SQLITE_DBSTATUS_LOOKASIDE_USED].
5187 ** Additional options will likely appear in future releases of SQLite.
5188 **
5189 ** The current value of the requested parameter is written into *pCur
5190 ** and the highest instantaneous value is written into *pHiwtr. If
5191 ** the resetFlg is true, then the highest instantaneous value is
5192 ** reset back down to the current value.
5193 **
5194 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
5195 */
5196 SQLITE_EXPERIMENTAL int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiw tr, int resetFlg);
5197
5198 /*
5199 ** CAPI3REF: Status Parameters for database connections {H17520} <H17500>
5200 ** EXPERIMENTAL
5201 **
5202 ** These constants are the available integer "verbs" that can be passed as
5203 ** the second argument to the [sqlite3_db_status()] interface.
5204 **
5205 ** New verbs may be added in future releases of SQLite. Existing verbs
5206 ** might be discontinued. Applications should check the return code from
5207 ** [sqlite3_db_status()] to make sure that the call worked.
5208 ** The [sqlite3_db_status()] interface will return a non-zero error code
5209 ** if a discontinued or unsupported verb is invoked.
5210 **
5211 ** <dl>
5212 ** <dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
5213 ** <dd>This parameter returns the number of lookaside memory slots currently
5214 ** checked out.</dd>
5215 ** </dl>
5216 */
5217 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
5218
5219
5220 /*
5221 ** CAPI3REF: Prepared Statement Status {H17550} <S60200>
5222 ** EXPERIMENTAL
5223 **
5224 ** Each prepared statement maintains various
5225 ** [SQLITE_STMTSTATUS_SORT | counters] that measure the number
5226 ** of times it has performed specific operations. These counters can
5227 ** be used to monitor the performance characteristics of the prepared
5228 ** statements. For example, if the number of table steps greatly exceeds
5229 ** the number of table searches or result rows, that would tend to indicate
5230 ** that the prepared statement is using a full table scan rather than
5231 ** an index.
5232 **
5233 ** This interface is used to retrieve and reset counter values from
5234 ** a [prepared statement]. The first argument is the prepared statement
5235 ** object to be interrogated. The second argument
5236 ** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter]
5237 ** to be interrogated.
5238 ** The current value of the requested counter is returned.
5239 ** If the resetFlg is true, then the counter is reset to zero after this
5240 ** interface call returns.
5241 **
5242 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
5243 */
5244 SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
5245
5246 /*
5247 ** CAPI3REF: Status Parameters for prepared statements {H17570} <H17550>
5248 ** EXPERIMENTAL
5249 **
5250 ** These preprocessor macros define integer codes that name counter
5251 ** values associated with the [sqlite3_stmt_status()] interface.
5252 ** The meanings of the various counters are as follows:
5253 **
5254 ** <dl>
5255 ** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
5256 ** <dd>This is the number of times that SQLite has stepped forward in
5257 ** a table as part of a full table scan. Large numbers for this counter
5258 ** may indicate opportunities for performance improvement through
5259 ** careful use of indices.</dd>
5260 **
5261 ** <dt>SQLITE_STMTSTATUS_SORT</dt>
5262 ** <dd>This is the number of sort operations that have occurred.
5263 ** A non-zero value in this counter may indicate an opportunity to
5264 ** improvement performance through careful use of indices.</dd>
5265 **
5266 ** </dl>
5267 */
5268 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
5269 #define SQLITE_STMTSTATUS_SORT 2
5270
5271 /*
5272 ** CAPI3REF: Custom Page Cache Object
5273 ** EXPERIMENTAL
5274 **
5275 ** The sqlite3_pcache type is opaque. It is implemented by
5276 ** the pluggable module. The SQLite core has no knowledge of
5277 ** its size or internal structure and never deals with the
5278 ** sqlite3_pcache object except by holding and passing pointers
5279 ** to the object.
5280 **
5281 ** See [sqlite3_pcache_methods] for additional information.
5282 */
5283 typedef struct sqlite3_pcache sqlite3_pcache;
5284
5285 /*
5286 ** CAPI3REF: Application Defined Page Cache.
5287 ** KEYWORDS: {page cache}
5288 ** EXPERIMENTAL
5289 **
5290 ** The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can
5291 ** register an alternative page cache implementation by passing in an
5292 ** instance of the sqlite3_pcache_methods structure. The majority of the
5293 ** heap memory used by SQLite is used by the page cache to cache data read
5294 ** from, or ready to be written to, the database file. By implementing a
5295 ** custom page cache using this API, an application can control more
5296 ** precisely the amount of memory consumed by SQLite, the way in which
5297 ** that memory is allocated and released, and the policies used to
5298 ** determine exactly which parts of a database file are cached and for
5299 ** how long.
5300 **
5301 ** The contents of the sqlite3_pcache_methods structure are copied to an
5302 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
5303 ** the application may discard the parameter after the call to
5304 ** [sqlite3_config()] returns.
5305 **
5306 ** The xInit() method is called once for each call to [sqlite3_initialize()]
5307 ** (usually only once during the lifetime of the process). It is passed
5308 ** a copy of the sqlite3_pcache_methods.pArg value. It can be used to set
5309 ** up global structures and mutexes required by the custom page cache
5310 ** implementation.
5311 **
5312 ** The xShutdown() method is called from within [sqlite3_shutdown()],
5313 ** if the application invokes this API. It can be used to clean up
5314 ** any outstanding resources before process shutdown, if required.
5315 **
5316 ** SQLite holds a [SQLITE_MUTEX_RECURSIVE] mutex when it invokes
5317 ** the xInit method, so the xInit method need not be threadsafe. The
5318 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
5319 ** not need to be threadsafe either. All other methods must be threadsafe
5320 ** in multithreaded applications.
5321 **
5322 ** SQLite will never invoke xInit() more than once without an intervening
5323 ** call to xShutdown().
5324 **
5325 ** The xCreate() method is used to construct a new cache instance. SQLite
5326 ** will typically create one cache instance for each open database file,
5327 ** though this is not guaranteed. The
5328 ** first parameter, szPage, is the size in bytes of the pages that must
5329 ** be allocated by the cache. szPage will not be a power of two. szPage
5330 ** will the page size of the database file that is to be cached plus an
5331 ** increment (here called "R") of about 100 or 200. SQLite will use the
5332 ** extra R bytes on each page to store metadata about the underlying
5333 ** database page on disk. The value of R depends
5334 ** on the SQLite version, the target platform, and how SQLite was compiled.
5335 ** R is constant for a particular build of SQLite. The second argument to
5336 ** xCreate(), bPurgeable, is true if the cache being created will
5337 ** be used to cache database pages of a file stored on disk, or
5338 ** false if it is used for an in-memory database. The cache implementation
5339 ** does not have to do anything special based with the value of bPurgeable;
5340 ** it is purely advisory. On a cache where bPurgeable is false, SQLite will
5341 ** never invoke xUnpin() except to deliberately delete a page.
5342 ** In other words, a cache created with bPurgeable set to false will
5343 ** never contain any unpinned pages.
5344 **
5345 ** The xCachesize() method may be called at any time by SQLite to set the
5346 ** suggested maximum cache-size (number of pages stored by) the cache
5347 ** instance passed as the first argument. This is the value configured using
5348 ** the SQLite "[PRAGMA cache_size]" command. As with the bPurgeable parameter,
5349 ** the implementation is not required to do anything with this
5350 ** value; it is advisory only.
5351 **
5352 ** The xPagecount() method should return the number of pages currently
5353 ** stored in the cache.
5354 **
5355 ** The xFetch() method is used to fetch a page and return a pointer to it.
5356 ** A 'page', in this context, is a buffer of szPage bytes aligned at an
5357 ** 8-byte boundary. The page to be fetched is determined by the key. The
5358 ** mimimum key value is 1. After it has been retrieved using xFetch, the page
5359 ** is considered to be "pinned".
5360 **
5361 ** If the requested page is already in the page cache, then the page cache
5362 ** implementation must return a pointer to the page buffer with its content
5363 ** intact. If the requested page is not already in the cache, then the
5364 ** behavior of the cache implementation is determined by the value of the
5365 ** createFlag parameter passed to xFetch, according to the following table:
5366 **
5367 ** <table border=1 width=85% align=center>
5368 ** <tr><th> createFlag <th> Behaviour when page is not already in cache
5369 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
5370 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
5371 ** Otherwise return NULL.
5372 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
5373 ** NULL if allocating a new page is effectively impossible.
5374 ** </table>
5375 **
5376 ** SQLite will normally invoke xFetch() with a createFlag of 0 or 1. If
5377 ** a call to xFetch() with createFlag==1 returns NULL, then SQLite will
5378 ** attempt to unpin one or more cache pages by spilling the content of
5379 ** pinned pages to disk and synching the operating system disk cache. After
5380 ** attempting to unpin pages, the xFetch() method will be invoked again with
5381 ** a createFlag of 2.
5382 **
5383 ** xUnpin() is called by SQLite with a pointer to a currently pinned page
5384 ** as its second argument. If the third parameter, discard, is non-zero,
5385 ** then the page should be evicted from the cache. In this case SQLite
5386 ** assumes that the next time the page is retrieved from the cache using
5387 ** the xFetch() method, it will be zeroed. If the discard parameter is
5388 ** zero, then the page is considered to be unpinned. The cache implementation
5389 ** may choose to evict unpinned pages at any time.
5390 **
5391 ** The cache is not required to perform any reference counting. A single
5392 ** call to xUnpin() unpins the page regardless of the number of prior calls
5393 ** to xFetch().
5394 **
5395 ** The xRekey() method is used to change the key value associated with the
5396 ** page passed as the second argument from oldKey to newKey. If the cache
5397 ** previously contains an entry associated with newKey, it should be
5398 ** discarded. Any prior cache entry associated with newKey is guaranteed not
5399 ** to be pinned.
5400 **
5401 ** When SQLite calls the xTruncate() method, the cache must discard all
5402 ** existing cache entries with page numbers (keys) greater than or equal
5403 ** to the value of the iLimit parameter passed to xTruncate(). If any
5404 ** of these pages are pinned, they are implicitly unpinned, meaning that
5405 ** they can be safely discarded.
5406 **
5407 ** The xDestroy() method is used to delete a cache allocated by xCreate().
5408 ** All resources associated with the specified cache should be freed. After
5409 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
5410 ** handle invalid, and will not use it with any other sqlite3_pcache_methods
5411 ** functions.
5412 */
5413 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
5414 struct sqlite3_pcache_methods {
5415 void *pArg;
5416 int (*xInit)(void*);
5417 void (*xShutdown)(void*);
5418 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
5419 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
5420 int (*xPagecount)(sqlite3_pcache*);
5421 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
5422 void (*xUnpin)(sqlite3_pcache*, void*, int discard);
5423 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
5424 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
5425 void (*xDestroy)(sqlite3_pcache*);
5426 };
5427
5428 /*
5429 ** CAPI3REF: Online Backup Object
5430 ** EXPERIMENTAL
5431 **
5432 ** The sqlite3_backup object records state information about an ongoing
5433 ** online backup operation. The sqlite3_backup object is created by
5434 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
5435 ** [sqlite3_backup_finish()].
5436 **
5437 ** See Also: [Using the SQLite Online Backup API]
5438 */
5439 typedef struct sqlite3_backup sqlite3_backup;
5440
5441 /*
5442 ** CAPI3REF: Online Backup API.
5443 ** EXPERIMENTAL
5444 **
5445 ** This API is used to overwrite the contents of one database with that
5446 ** of another. It is useful either for creating backups of databases or
5447 ** for copying in-memory databases to or from persistent files.
5448 **
5449 ** See Also: [Using the SQLite Online Backup API]
5450 **
5451 ** Exclusive access is required to the destination database for the
5452 ** duration of the operation. However the source database is only
5453 ** read-locked while it is actually being read, it is not locked
5454 ** continuously for the entire operation. Thus, the backup may be
5455 ** performed on a live database without preventing other users from
5456 ** writing to the database for an extended period of time.
5457 **
5458 ** To perform a backup operation:
5459 ** <ol>
5460 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
5461 ** backup,
5462 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
5463 ** the data between the two databases, and finally
5464 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
5465 ** associated with the backup operation.
5466 ** </ol>
5467 ** There should be exactly one call to sqlite3_backup_finish() for each
5468 ** successful call to sqlite3_backup_init().
5469 **
5470 ** <b>sqlite3_backup_init()</b>
5471 **
5472 ** The first two arguments passed to [sqlite3_backup_init()] are the database
5473 ** handle associated with the destination database and the database name
5474 ** used to attach the destination database to the handle. The database name
5475 ** is "main" for the main database, "temp" for the temporary database, or
5476 ** the name specified as part of the [ATTACH] statement if the destination is
5477 ** an attached database. The third and fourth arguments passed to
5478 ** sqlite3_backup_init() identify the [database connection]
5479 ** and database name used
5480 ** to access the source database. The values passed for the source and
5481 ** destination [database connection] parameters must not be the same.
5482 **
5483 ** If an error occurs within sqlite3_backup_init(), then NULL is returned
5484 ** and an error code and error message written into the [database connection]
5485 ** passed as the first argument. They may be retrieved using the
5486 ** [sqlite3_errcode()], [sqlite3_errmsg()], and [sqlite3_errmsg16()] functions.
5487 ** Otherwise, if successful, a pointer to an [sqlite3_backup] object is
5488 ** returned. This pointer may be used with the sqlite3_backup_step() and
5489 ** sqlite3_backup_finish() functions to perform the specified backup
5490 ** operation.
5491 **
5492 ** <b>sqlite3_backup_step()</b>
5493 **
5494 ** Function [sqlite3_backup_step()] is used to copy up to nPage pages between
5495 ** the source and destination databases, where nPage is the value of the
5496 ** second parameter passed to sqlite3_backup_step(). If nPage is a negative
5497 ** value, all remaining source pages are copied. If the required pages are
5498 ** succesfully copied, but there are still more pages to copy before the
5499 ** backup is complete, it returns [SQLITE_OK]. If no error occured and there
5500 ** are no more pages to copy, then [SQLITE_DONE] is returned. If an error
5501 ** occurs, then an SQLite error code is returned. As well as [SQLITE_OK] and
5502 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
5503 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
5504 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
5505 **
5506 ** As well as the case where the destination database file was opened for
5507 ** read-only access, sqlite3_backup_step() may return [SQLITE_READONLY] if
5508 ** the destination is an in-memory database with a different page size
5509 ** from the source database.
5510 **
5511 ** If sqlite3_backup_step() cannot obtain a required file-system lock, then
5512 ** the [sqlite3_busy_handler | busy-handler function]
5513 ** is invoked (if one is specified). If the
5514 ** busy-handler returns non-zero before the lock is available, then
5515 ** [SQLITE_BUSY] is returned to the caller. In this case the call to
5516 ** sqlite3_backup_step() can be retried later. If the source
5517 ** [database connection]
5518 ** is being used to write to the source database when sqlite3_backup_step()
5519 ** is called, then [SQLITE_LOCKED] is returned immediately. Again, in this
5520 ** case the call to sqlite3_backup_step() can be retried later on. If
5521 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
5522 ** [SQLITE_READONLY] is returned, then
5523 ** there is no point in retrying the call to sqlite3_backup_step(). These
5524 ** errors are considered fatal. At this point the application must accept
5525 ** that the backup operation has failed and pass the backup operation handle
5526 ** to the sqlite3_backup_finish() to release associated resources.
5527 **
5528 ** Following the first call to sqlite3_backup_step(), an exclusive lock is
5529 ** obtained on the destination file. It is not released until either
5530 ** sqlite3_backup_finish() is called or the backup operation is complete
5531 ** and sqlite3_backup_step() returns [SQLITE_DONE]. Additionally, each time
5532 ** a call to sqlite3_backup_step() is made a [shared lock] is obtained on
5533 ** the source database file. This lock is released before the
5534 ** sqlite3_backup_step() call returns. Because the source database is not
5535 ** locked between calls to sqlite3_backup_step(), it may be modified mid-way
5536 ** through the backup procedure. If the source database is modified by an
5537 ** external process or via a database connection other than the one being
5538 ** used by the backup operation, then the backup will be transparently
5539 ** restarted by the next call to sqlite3_backup_step(). If the source
5540 ** database is modified by the using the same database connection as is used
5541 ** by the backup operation, then the backup database is transparently
5542 ** updated at the same time.
5543 **
5544 ** <b>sqlite3_backup_finish()</b>
5545 **
5546 ** Once sqlite3_backup_step() has returned [SQLITE_DONE], or when the
5547 ** application wishes to abandon the backup operation, the [sqlite3_backup]
5548 ** object should be passed to sqlite3_backup_finish(). This releases all
5549 ** resources associated with the backup operation. If sqlite3_backup_step()
5550 ** has not yet returned [SQLITE_DONE], then any active write-transaction on the
5551 ** destination database is rolled back. The [sqlite3_backup] object is invalid
5552 ** and may not be used following a call to sqlite3_backup_finish().
5553 **
5554 ** The value returned by sqlite3_backup_finish is [SQLITE_OK] if no error
5555 ** occurred, regardless or whether or not sqlite3_backup_step() was called
5556 ** a sufficient number of times to complete the backup operation. Or, if
5557 ** an out-of-memory condition or IO error occured during a call to
5558 ** sqlite3_backup_step() then [SQLITE_NOMEM] or an
5559 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] error code
5560 ** is returned. In this case the error code and an error message are
5561 ** written to the destination [database connection].
5562 **
5563 ** A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() is
5564 ** not a permanent error and does not affect the return value of
5565 ** sqlite3_backup_finish().
5566 **
5567 ** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b>
5568 **
5569 ** Each call to sqlite3_backup_step() sets two values stored internally
5570 ** by an [sqlite3_backup] object. The number of pages still to be backed
5571 ** up, which may be queried by sqlite3_backup_remaining(), and the total
5572 ** number of pages in the source database file, which may be queried by
5573 ** sqlite3_backup_pagecount().
5574 **
5575 ** The values returned by these functions are only updated by
5576 ** sqlite3_backup_step(). If the source database is modified during a backup
5577 ** operation, then the values are not updated to account for any extra
5578 ** pages that need to be updated or the size of the source database file
5579 ** changing.
5580 **
5581 ** <b>Concurrent Usage of Database Handles</b>
5582 **
5583 ** The source [database connection] may be used by the application for other
5584 ** purposes while a backup operation is underway or being initialized.
5585 ** If SQLite is compiled and configured to support threadsafe database
5586 ** connections, then the source database connection may be used concurrently
5587 ** from within other threads.
5588 **
5589 ** However, the application must guarantee that the destination database
5590 ** connection handle is not passed to any other API (by any thread) after
5591 ** sqlite3_backup_init() is called and before the corresponding call to
5592 ** sqlite3_backup_finish(). Unfortunately SQLite does not currently check
5593 ** for this, if the application does use the destination [database connection]
5594 ** for some other purpose during a backup operation, things may appear to
5595 ** work correctly but in fact be subtly malfunctioning. Use of the
5596 ** destination database connection while a backup is in progress might
5597 ** also cause a mutex deadlock.
5598 **
5599 ** Furthermore, if running in [shared cache mode], the application must
5600 ** guarantee that the shared cache used by the destination database
5601 ** is not accessed while the backup is running. In practice this means
5602 ** that the application must guarantee that the file-system file being
5603 ** backed up to is not accessed by any connection within the process,
5604 ** not just the specific connection that was passed to sqlite3_backup_init().
5605 **
5606 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
5607 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
5608 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
5609 ** APIs are not strictly speaking threadsafe. If they are invoked at the
5610 ** same time as another thread is invoking sqlite3_backup_step() it is
5611 ** possible that they return invalid values.
5612 */
5613 sqlite3_backup *sqlite3_backup_init(
5614 sqlite3 *pDest, /* Destination database handle */
5615 const char *zDestName, /* Destination database name */
5616 sqlite3 *pSource, /* Source database handle */
5617 const char *zSourceName /* Source database name */
5618 );
5619 int sqlite3_backup_step(sqlite3_backup *p, int nPage);
5620 int sqlite3_backup_finish(sqlite3_backup *p);
5621 int sqlite3_backup_remaining(sqlite3_backup *p);
5622 int sqlite3_backup_pagecount(sqlite3_backup *p);
5623
5624 /*
5625 ** CAPI3REF: Unlock Notification
5626 ** EXPERIMENTAL
5627 **
5628 ** When running in shared-cache mode, a database operation may fail with
5629 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
5630 ** individual tables within the shared-cache cannot be obtained. See
5631 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
5632 ** This API may be used to register a callback that SQLite will invoke
5633 ** when the connection currently holding the required lock relinquishes it.
5634 ** This API is only available if the library was compiled with the
5635 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
5636 **
5637 ** See Also: [Using the SQLite Unlock Notification Feature].
5638 **
5639 ** Shared-cache locks are released when a database connection concludes
5640 ** its current transaction, either by committing it or rolling it back.
5641 **
5642 ** When a connection (known as the blocked connection) fails to obtain a
5643 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
5644 ** identity of the database connection (the blocking connection) that
5645 ** has locked the required resource is stored internally. After an
5646 ** application receives an SQLITE_LOCKED error, it may call the
5647 ** sqlite3_unlock_notify() method with the blocked connection handle as
5648 ** the first argument to register for a callback that will be invoked
5649 ** when the blocking connections current transaction is concluded. The
5650 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
5651 ** call that concludes the blocking connections transaction.
5652 **
5653 ** If sqlite3_unlock_notify() is called in a multi-threaded application,
5654 ** there is a chance that the blocking connection will have already
5655 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
5656 ** If this happens, then the specified callback is invoked immediately,
5657 ** from within the call to sqlite3_unlock_notify().
5658 **
5659 ** If the blocked connection is attempting to obtain a write-lock on a
5660 ** shared-cache table, and more than one other connection currently holds
5661 ** a read-lock on the same table, then SQLite arbitrarily selects one of
5662 ** the other connections to use as the blocking connection.
5663 **
5664 ** There may be at most one unlock-notify callback registered by a
5665 ** blocked connection. If sqlite3_unlock_notify() is called when the
5666 ** blocked connection already has a registered unlock-notify callback,
5667 ** then the new callback replaces the old. If sqlite3_unlock_notify() is
5668 ** called with a NULL pointer as its second argument, then any existing
5669 ** unlock-notify callback is cancelled. The blocked connections
5670 ** unlock-notify callback may also be canceled by closing the blocked
5671 ** connection using [sqlite3_close()].
5672 **
5673 ** The unlock-notify callback is not reentrant. If an application invokes
5674 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
5675 ** crash or deadlock may be the result.
5676 **
5677 ** Unless deadlock is detected (see below), sqlite3_unlock_notify() always
5678 ** returns SQLITE_OK.
5679 **
5680 ** <b>Callback Invocation Details</b>
5681 **
5682 ** When an unlock-notify callback is registered, the application provides a
5683 ** single void* pointer that is passed to the callback when it is invoked.
5684 ** However, the signature of the callback function allows SQLite to pass
5685 ** it an array of void* context pointers. The first argument passed to
5686 ** an unlock-notify callback is a pointer to an array of void* pointers,
5687 ** and the second is the number of entries in the array.
5688 **
5689 ** When a blocking connections transaction is concluded, there may be
5690 ** more than one blocked connection that has registered for an unlock-notify
5691 ** callback. If two or more such blocked connections have specified the
5692 ** same callback function, then instead of invoking the callback function
5693 ** multiple times, it is invoked once with the set of void* context pointers
5694 ** specified by the blocked connections bundled together into an array.
5695 ** This gives the application an opportunity to prioritize any actions
5696 ** related to the set of unblocked database connections.
5697 **
5698 ** <b>Deadlock Detection</b>
5699 **
5700 ** Assuming that after registering for an unlock-notify callback a
5701 ** database waits for the callback to be issued before taking any further
5702 ** action (a reasonable assumption), then using this API may cause the
5703 ** application to deadlock. For example, if connection X is waiting for
5704 ** connection Y's transaction to be concluded, and similarly connection
5705 ** Y is waiting on connection X's transaction, then neither connection
5706 ** will proceed and the system may remain deadlocked indefinitely.
5707 **
5708 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
5709 ** detection. If a given call to sqlite3_unlock_notify() would put the
5710 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
5711 ** unlock-notify callback is registered. The system is said to be in
5712 ** a deadlocked state if connection A has registered for an unlock-notify
5713 ** callback on the conclusion of connection B's transaction, and connection
5714 ** B has itself registered for an unlock-notify callback when connection
5715 ** A's transaction is concluded. Indirect deadlock is also detected, so
5716 ** the system is also considered to be deadlocked if connection B has
5717 ** registered for an unlock-notify callback on the conclusion of connection
5718 ** C's transaction, where connection C is waiting on connection A. Any
5719 ** number of levels of indirection are allowed.
5720 **
5721 ** <b>The "DROP TABLE" Exception</b>
5722 **
5723 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
5724 ** always appropriate to call sqlite3_unlock_notify(). There is however,
5725 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
5726 ** SQLite checks if there are any currently executing SELECT statements
5727 ** that belong to the same connection. If there are, SQLITE_LOCKED is
5728 ** returned. In this case there is no "blocking connection", so invoking
5729 ** sqlite3_unlock_notify() results in the unlock-notify callback being
5730 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
5731 ** or "DROP INDEX" query, an infinite loop might be the result.
5732 **
5733 ** One way around this problem is to check the extended error code returned
5734 ** by an sqlite3_step() call. If there is a blocking connection, then the
5735 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
5736 ** the special "DROP TABLE/INDEX" case, the extended error code is just
5737 ** SQLITE_LOCKED.
5738 */
5739 int sqlite3_unlock_notify(
5740 sqlite3 *pBlocked, /* Waiting connection */
5741 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
5742 void *pNotifyArg /* Argument to pass to xNotify */
5743 );
5744
5745
5746 /*
5747 ** CAPI3REF: String Comparison
5748 ** EXPERIMENTAL
5749 **
5750 ** The [sqlite3_strnicmp()] API allows applications and extensions to
5751 ** compare the contents of two buffers containing UTF-8 strings in a
5752 ** case-indendent fashion, using the same definition of case independence
5753 ** that SQLite uses internally when comparing identifiers.
5754 */
5755 int sqlite3_strnicmp(const char *, const char *, int);
5756
5757 /*
5758 ** Undo the hack that converts floating point types to integer for
5759 ** builds on processors without floating point support.
5760 */
5761 #ifdef SQLITE_OMIT_FLOATING_POINT
5762 # undef double
5763 #endif
5764
5765 #ifdef __cplusplus
5766 } /* End of the 'extern "C"' block */
5767 #endif
5768 #endif
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