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comparison sqlite/sqlite3.h @ 0:1e5118fa0cb1

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This is NSS with a Cmake Buildsyste To compile a static NSS library for Windows we've used the Chromium-NSS fork and added a Cmake buildsystem to compile it statically for Windows. See README.chromium for chromium changes and README.trustbridge for our modifications.
author Andre Heinecke <andre.heinecke@intevation.de>
date Mon, 28 Jul 2014 10:47:06 +0200
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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 #ifndef SQLITE_API
53 # define SQLITE_API
54 #endif
55
56
57 /*
58 ** These no-op macros are used in front of interfaces to mark those
59 ** interfaces as either deprecated or experimental. New applications
60 ** should not use deprecated interfaces - they are support for backwards
61 ** compatibility only. Application writers should be aware that
62 ** experimental interfaces are subject to change in point releases.
63 **
64 ** These macros used to resolve to various kinds of compiler magic that
65 ** would generate warning messages when they were used. But that
66 ** compiler magic ended up generating such a flurry of bug reports
67 ** that we have taken it all out and gone back to using simple
68 ** noop macros.
69 */
70 #define SQLITE_DEPRECATED
71 #define SQLITE_EXPERIMENTAL
72
73 /*
74 ** Ensure these symbols were not defined by some previous header file.
75 */
76 #ifdef SQLITE_VERSION
77 # undef SQLITE_VERSION
78 #endif
79 #ifdef SQLITE_VERSION_NUMBER
80 # undef SQLITE_VERSION_NUMBER
81 #endif
82
83 /*
84 ** CAPI3REF: Compile-Time Library Version Numbers
85 **
86 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
87 ** evaluates to a string literal that is the SQLite version in the
88 ** format "X.Y.Z" where X is the major version number (always 3 for
89 ** SQLite3) and Y is the minor version number and Z is the release number.)^
90 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
91 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
92 ** numbers used in [SQLITE_VERSION].)^
93 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
94 ** be larger than the release from which it is derived. Either Y will
95 ** be held constant and Z will be incremented or else Y will be incremented
96 ** and Z will be reset to zero.
97 **
98 ** Since version 3.6.18, SQLite source code has been stored in the
99 ** <a href="http://www.fossil-scm.org/">Fossil configuration management
100 ** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to
101 ** a string which identifies a particular check-in of SQLite
102 ** within its configuration management system. ^The SQLITE_SOURCE_ID
103 ** string contains the date and time of the check-in (UTC) and an SHA1
104 ** hash of the entire source tree.
105 **
106 ** See also: [sqlite3_libversion()],
107 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
108 ** [sqlite_version()] and [sqlite_source_id()].
109 */
110 #define SQLITE_VERSION "3.8.5"
111 #define SQLITE_VERSION_NUMBER 3008005
112 #define SQLITE_SOURCE_ID "2014-06-04 14:06:34 b1ed4f2a34ba66c29b130f8d13e9092758019212"
113
114 /*
115 ** CAPI3REF: Run-Time Library Version Numbers
116 ** KEYWORDS: sqlite3_version, sqlite3_sourceid
117 **
118 ** These interfaces provide the same information as the [SQLITE_VERSION],
119 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
120 ** but are associated with the library instead of the header file. ^(Cautious
121 ** programmers might include assert() statements in their application to
122 ** verify that values returned by these interfaces match the macros in
123 ** the header, and thus insure that the application is
124 ** compiled with matching library and header files.
125 **
126 ** <blockquote><pre>
127 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
128 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
129 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
130 ** </pre></blockquote>)^
131 **
132 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
133 ** macro. ^The sqlite3_libversion() function returns a pointer to the
134 ** to the sqlite3_version[] string constant. The sqlite3_libversion()
135 ** function is provided for use in DLLs since DLL users usually do not have
136 ** direct access to string constants within the DLL. ^The
137 ** sqlite3_libversion_number() function returns an integer equal to
138 ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns
139 ** a pointer to a string constant whose value is the same as the
140 ** [SQLITE_SOURCE_ID] C preprocessor macro.
141 **
142 ** See also: [sqlite_version()] and [sqlite_source_id()].
143 */
144 SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
145 SQLITE_API const char *sqlite3_libversion(void);
146 SQLITE_API const char *sqlite3_sourceid(void);
147 SQLITE_API int sqlite3_libversion_number(void);
148
149 /*
150 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
151 **
152 ** ^The sqlite3_compileoption_used() function returns 0 or 1
153 ** indicating whether the specified option was defined at
154 ** compile time. ^The SQLITE_ prefix may be omitted from the
155 ** option name passed to sqlite3_compileoption_used().
156 **
157 ** ^The sqlite3_compileoption_get() function allows iterating
158 ** over the list of options that were defined at compile time by
159 ** returning the N-th compile time option string. ^If N is out of range,
160 ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
161 ** prefix is omitted from any strings returned by
162 ** sqlite3_compileoption_get().
163 **
164 ** ^Support for the diagnostic functions sqlite3_compileoption_used()
165 ** and sqlite3_compileoption_get() may be omitted by specifying the
166 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
167 **
168 ** See also: SQL functions [sqlite_compileoption_used()] and
169 ** [sqlite_compileoption_get()] and the [compile_options pragma].
170 */
171 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
172 SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
173 SQLITE_API const char *sqlite3_compileoption_get(int N);
174 #endif
175
176 /*
177 ** CAPI3REF: Test To See If The Library Is Threadsafe
178 **
179 ** ^The sqlite3_threadsafe() function returns zero if and only if
180 ** SQLite was compiled with mutexing code omitted due to the
181 ** [SQLITE_THREADSAFE] compile-time option being set to 0.
182 **
183 ** SQLite can be compiled with or without mutexes. When
184 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
185 ** are enabled and SQLite is threadsafe. When the
186 ** [SQLITE_THREADSAFE] macro is 0,
187 ** the mutexes are omitted. Without the mutexes, it is not safe
188 ** to use SQLite concurrently from more than one thread.
189 **
190 ** Enabling mutexes incurs a measurable performance penalty.
191 ** So if speed is of utmost importance, it makes sense to disable
192 ** the mutexes. But for maximum safety, mutexes should be enabled.
193 ** ^The default behavior is for mutexes to be enabled.
194 **
195 ** This interface can be used by an application to make sure that the
196 ** version of SQLite that it is linking against was compiled with
197 ** the desired setting of the [SQLITE_THREADSAFE] macro.
198 **
199 ** This interface only reports on the compile-time mutex setting
200 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
201 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
202 ** can be fully or partially disabled using a call to [sqlite3_config()]
203 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
204 ** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the
205 ** sqlite3_threadsafe() function shows only the compile-time setting of
206 ** thread safety, not any run-time changes to that setting made by
207 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
208 ** is unchanged by calls to sqlite3_config().)^
209 **
210 ** See the [threading mode] documentation for additional information.
211 */
212 SQLITE_API int sqlite3_threadsafe(void);
213
214 /*
215 ** CAPI3REF: Database Connection Handle
216 ** KEYWORDS: {database connection} {database connections}
217 **
218 ** Each open SQLite database is represented by a pointer to an instance of
219 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3
220 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
221 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
222 ** and [sqlite3_close_v2()] are its destructors. There are many other
223 ** interfaces (such as
224 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
225 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
226 ** sqlite3 object.
227 */
228 typedef struct sqlite3 sqlite3;
229
230 /*
231 ** CAPI3REF: 64-Bit Integer Types
232 ** KEYWORDS: sqlite_int64 sqlite_uint64
233 **
234 ** Because there is no cross-platform way to specify 64-bit integer types
235 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
236 **
237 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
238 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
239 ** compatibility only.
240 **
241 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
242 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
243 ** sqlite3_uint64 and sqlite_uint64 types can store integer values
244 ** between 0 and +18446744073709551615 inclusive.
245 */
246 #ifdef SQLITE_INT64_TYPE
247 typedef SQLITE_INT64_TYPE sqlite_int64;
248 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
249 #elif defined(_MSC_VER) || defined(__BORLANDC__)
250 typedef __int64 sqlite_int64;
251 typedef unsigned __int64 sqlite_uint64;
252 #else
253 typedef long long int sqlite_int64;
254 typedef unsigned long long int sqlite_uint64;
255 #endif
256 typedef sqlite_int64 sqlite3_int64;
257 typedef sqlite_uint64 sqlite3_uint64;
258
259 /*
260 ** If compiling for a processor that lacks floating point support,
261 ** substitute integer for floating-point.
262 */
263 #ifdef SQLITE_OMIT_FLOATING_POINT
264 # define double sqlite3_int64
265 #endif
266
267 /*
268 ** CAPI3REF: Closing A Database Connection
269 **
270 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
271 ** for the [sqlite3] object.
272 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return SQLITE_OK if
273 ** the [sqlite3] object is successfully destroyed and all associated
274 ** resources are deallocated.
275 **
276 ** ^If the database connection is associated with unfinalized prepared
277 ** statements or unfinished sqlite3_backup objects then sqlite3_close()
278 ** will leave the database connection open and return [SQLITE_BUSY].
279 ** ^If sqlite3_close_v2() is called with unfinalized prepared statements
280 ** and unfinished sqlite3_backups, then the database connection becomes
281 ** an unusable "zombie" which will automatically be deallocated when the
282 ** last prepared statement is finalized or the last sqlite3_backup is
283 ** finished. The sqlite3_close_v2() interface is intended for use with
284 ** host languages that are garbage collected, and where the order in which
285 ** destructors are called is arbitrary.
286 **
287 ** Applications should [sqlite3_finalize | finalize] all [prepared statements],
288 ** [sqlite3_blob_close | close] all [BLOB handles], and
289 ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
290 ** with the [sqlite3] object prior to attempting to close the object. ^If
291 ** sqlite3_close_v2() is called on a [database connection] that still has
292 ** outstanding [prepared statements], [BLOB handles], and/or
293 ** [sqlite3_backup] objects then it returns SQLITE_OK but the deallocation
294 ** of resources is deferred until all [prepared statements], [BLOB handles],
295 ** and [sqlite3_backup] objects are also destroyed.
296 **
297 ** ^If an [sqlite3] object is destroyed while a transaction is open,
298 ** the transaction is automatically rolled back.
299 **
300 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
301 ** must be either a NULL
302 ** pointer or an [sqlite3] object pointer obtained
303 ** from [sqlite3_open()], [sqlite3_open16()], or
304 ** [sqlite3_open_v2()], and not previously closed.
305 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
306 ** argument is a harmless no-op.
307 */
308 SQLITE_API int sqlite3_close(sqlite3*);
309 SQLITE_API int sqlite3_close_v2(sqlite3*);
310
311 /*
312 ** The type for a callback function.
313 ** This is legacy and deprecated. It is included for historical
314 ** compatibility and is not documented.
315 */
316 typedef int (*sqlite3_callback)(void*,int,char**, char**);
317
318 /*
319 ** CAPI3REF: One-Step Query Execution Interface
320 **
321 ** The sqlite3_exec() interface is a convenience wrapper around
322 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
323 ** that allows an application to run multiple statements of SQL
324 ** without having to use a lot of C code.
325 **
326 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
327 ** semicolon-separate SQL statements passed into its 2nd argument,
328 ** in the context of the [database connection] passed in as its 1st
329 ** argument. ^If the callback function of the 3rd argument to
330 ** sqlite3_exec() is not NULL, then it is invoked for each result row
331 ** coming out of the evaluated SQL statements. ^The 4th argument to
332 ** sqlite3_exec() is relayed through to the 1st argument of each
333 ** callback invocation. ^If the callback pointer to sqlite3_exec()
334 ** is NULL, then no callback is ever invoked and result rows are
335 ** ignored.
336 **
337 ** ^If an error occurs while evaluating the SQL statements passed into
338 ** sqlite3_exec(), then execution of the current statement stops and
339 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
340 ** is not NULL then any error message is written into memory obtained
341 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
342 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
343 ** on error message strings returned through the 5th parameter of
344 ** of sqlite3_exec() after the error message string is no longer needed.
345 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
346 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
347 ** NULL before returning.
348 **
349 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
350 ** routine returns SQLITE_ABORT without invoking the callback again and
351 ** without running any subsequent SQL statements.
352 **
353 ** ^The 2nd argument to the sqlite3_exec() callback function is the
354 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
355 ** callback is an array of pointers to strings obtained as if from
356 ** [sqlite3_column_text()], one for each column. ^If an element of a
357 ** result row is NULL then the corresponding string pointer for the
358 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
359 ** sqlite3_exec() callback is an array of pointers to strings where each
360 ** entry represents the name of corresponding result column as obtained
361 ** from [sqlite3_column_name()].
362 **
363 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
364 ** to an empty string, or a pointer that contains only whitespace and/or
365 ** SQL comments, then no SQL statements are evaluated and the database
366 ** is not changed.
367 **
368 ** Restrictions:
369 **
370 ** <ul>
371 ** <li> The application must insure that the 1st parameter to sqlite3_exec()
372 ** is a valid and open [database connection].
373 ** <li> The application must not close the [database connection] specified by
374 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
375 ** <li> The application must not modify the SQL statement text passed into
376 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
377 ** </ul>
378 */
379 SQLITE_API int sqlite3_exec(
380 sqlite3*, /* An open database */
381 const char *sql, /* SQL to be evaluated */
382 int (*callback)(void*,int,char**,char**), /* Callback function */
383 void *, /* 1st argument to callback */
384 char **errmsg /* Error msg written here */
385 );
386
387 /*
388 ** CAPI3REF: Result Codes
389 ** KEYWORDS: SQLITE_OK {error code} {error codes}
390 ** KEYWORDS: {result code} {result codes}
391 **
392 ** Many SQLite functions return an integer result code from the set shown
393 ** here in order to indicate success or failure.
394 **
395 ** New error codes may be added in future versions of SQLite.
396 **
397 ** See also: [SQLITE_IOERR_READ | extended result codes],
398 ** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes].
399 */
400 #define SQLITE_OK 0 /* Successful result */
401 /* beginning-of-error-codes */
402 #define SQLITE_ERROR 1 /* SQL error or missing database */
403 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
404 #define SQLITE_PERM 3 /* Access permission denied */
405 #define SQLITE_ABORT 4 /* Callback routine requested an abort */
406 #define SQLITE_BUSY 5 /* The database file is locked */
407 #define SQLITE_LOCKED 6 /* A table in the database is locked */
408 #define SQLITE_NOMEM 7 /* A malloc() failed */
409 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */
410 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
411 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
412 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */
413 #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
414 #define SQLITE_FULL 13 /* Insertion failed because database is full */
415 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */
416 #define SQLITE_PROTOCOL 15 /* Database lock protocol error */
417 #define SQLITE_EMPTY 16 /* Database is empty */
418 #define SQLITE_SCHEMA 17 /* The database schema changed */
419 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
420 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
421 #define SQLITE_MISMATCH 20 /* Data type mismatch */
422 #define SQLITE_MISUSE 21 /* Library used incorrectly */
423 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
424 #define SQLITE_AUTH 23 /* Authorization denied */
425 #define SQLITE_FORMAT 24 /* Auxiliary database format error */
426 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
427 #define SQLITE_NOTADB 26 /* File opened that is not a database file */
428 #define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */
429 #define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */
430 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
431 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
432 /* end-of-error-codes */
433
434 /*
435 ** CAPI3REF: Extended Result Codes
436 ** KEYWORDS: {extended error code} {extended error codes}
437 ** KEYWORDS: {extended result code} {extended result codes}
438 **
439 ** In its default configuration, SQLite API routines return one of 26 integer
440 ** [SQLITE_OK | result codes]. However, experience has shown that many of
441 ** these result codes are too coarse-grained. They do not provide as
442 ** much information about problems as programmers might like. In an effort to
443 ** address this, newer versions of SQLite (version 3.3.8 and later) include
444 ** support for additional result codes that provide more detailed information
445 ** about errors. The extended result codes are enabled or disabled
446 ** on a per database connection basis using the
447 ** [sqlite3_extended_result_codes()] API.
448 **
449 ** Some of the available extended result codes are listed here.
450 ** One may expect the number of extended result codes will increase
451 ** over time. Software that uses extended result codes should expect
452 ** to see new result codes in future releases of SQLite.
453 **
454 ** The SQLITE_OK result code will never be extended. It will always
455 ** be exactly zero.
456 */
457 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
458 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
459 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
460 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
461 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
462 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
463 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
464 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
465 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
466 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
467 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
468 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
469 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
470 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
471 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
472 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
473 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
474 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
475 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
476 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
477 #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
478 #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
479 #define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
480 #define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
481 #define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8))
482 #define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8))
483 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
484 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
485 #define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8))
486 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
487 #define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
488 #define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
489 #define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8))
490 #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
491 #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
492 #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
493 #define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8))
494 #define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8))
495 #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
496 #define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8))
497 #define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8))
498 #define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8))
499 #define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8))
500 #define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8))
501 #define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8))
502 #define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8))
503 #define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8))
504 #define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8))
505 #define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8))
506 #define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8))
507 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
508 #define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8))
509
510 /*
511 ** CAPI3REF: Flags For File Open Operations
512 **
513 ** These bit values are intended for use in the
514 ** 3rd parameter to the [sqlite3_open_v2()] interface and
515 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
516 */
517 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
518 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
519 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
520 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
521 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
522 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
523 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
524 #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
525 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
526 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
527 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
528 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
529 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
530 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
531 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
532 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
533 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
534 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
535 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
536 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
537
538 /* Reserved: 0x00F00000 */
539
540 /*
541 ** CAPI3REF: Device Characteristics
542 **
543 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
544 ** object returns an integer which is a vector of these
545 ** bit values expressing I/O characteristics of the mass storage
546 ** device that holds the file that the [sqlite3_io_methods]
547 ** refers to.
548 **
549 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
550 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
551 ** mean that writes of blocks that are nnn bytes in size and
552 ** are aligned to an address which is an integer multiple of
553 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
554 ** that when data is appended to a file, the data is appended
555 ** first then the size of the file is extended, never the other
556 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
557 ** information is written to disk in the same order as calls
558 ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
559 ** after reboot following a crash or power loss, the only bytes in a
560 ** file that were written at the application level might have changed
561 ** and that adjacent bytes, even bytes within the same sector are
562 ** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
563 ** flag indicate that a file cannot be deleted when open. The
564 ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
565 ** read-only media and cannot be changed even by processes with
566 ** elevated privileges.
567 */
568 #define SQLITE_IOCAP_ATOMIC 0x00000001
569 #define SQLITE_IOCAP_ATOMIC512 0x00000002
570 #define SQLITE_IOCAP_ATOMIC1K 0x00000004
571 #define SQLITE_IOCAP_ATOMIC2K 0x00000008
572 #define SQLITE_IOCAP_ATOMIC4K 0x00000010
573 #define SQLITE_IOCAP_ATOMIC8K 0x00000020
574 #define SQLITE_IOCAP_ATOMIC16K 0x00000040
575 #define SQLITE_IOCAP_ATOMIC32K 0x00000080
576 #define SQLITE_IOCAP_ATOMIC64K 0x00000100
577 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
578 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
579 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
580 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
581 #define SQLITE_IOCAP_IMMUTABLE 0x00002000
582
583 /*
584 ** CAPI3REF: File Locking Levels
585 **
586 ** SQLite uses one of these integer values as the second
587 ** argument to calls it makes to the xLock() and xUnlock() methods
588 ** of an [sqlite3_io_methods] object.
589 */
590 #define SQLITE_LOCK_NONE 0
591 #define SQLITE_LOCK_SHARED 1
592 #define SQLITE_LOCK_RESERVED 2
593 #define SQLITE_LOCK_PENDING 3
594 #define SQLITE_LOCK_EXCLUSIVE 4
595
596 /*
597 ** CAPI3REF: Synchronization Type Flags
598 **
599 ** When SQLite invokes the xSync() method of an
600 ** [sqlite3_io_methods] object it uses a combination of
601 ** these integer values as the second argument.
602 **
603 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
604 ** sync operation only needs to flush data to mass storage. Inode
605 ** information need not be flushed. If the lower four bits of the flag
606 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
607 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
608 ** to use Mac OS X style fullsync instead of fsync().
609 **
610 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
611 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
612 ** settings. The [synchronous pragma] determines when calls to the
613 ** xSync VFS method occur and applies uniformly across all platforms.
614 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
615 ** energetic or rigorous or forceful the sync operations are and
616 ** only make a difference on Mac OSX for the default SQLite code.
617 ** (Third-party VFS implementations might also make the distinction
618 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
619 ** operating systems natively supported by SQLite, only Mac OSX
620 ** cares about the difference.)
621 */
622 #define SQLITE_SYNC_NORMAL 0x00002
623 #define SQLITE_SYNC_FULL 0x00003
624 #define SQLITE_SYNC_DATAONLY 0x00010
625
626 /*
627 ** CAPI3REF: OS Interface Open File Handle
628 **
629 ** An [sqlite3_file] object represents an open file in the
630 ** [sqlite3_vfs | OS interface layer]. Individual OS interface
631 ** implementations will
632 ** want to subclass this object by appending additional fields
633 ** for their own use. The pMethods entry is a pointer to an
634 ** [sqlite3_io_methods] object that defines methods for performing
635 ** I/O operations on the open file.
636 */
637 typedef struct sqlite3_file sqlite3_file;
638 struct sqlite3_file {
639 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
640 };
641
642 /*
643 ** CAPI3REF: OS Interface File Virtual Methods Object
644 **
645 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
646 ** [sqlite3_file] object (or, more commonly, a subclass of the
647 ** [sqlite3_file] object) with a pointer to an instance of this object.
648 ** This object defines the methods used to perform various operations
649 ** against the open file represented by the [sqlite3_file] object.
650 **
651 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
652 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
653 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
654 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
655 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
656 ** to NULL.
657 **
658 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
659 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
660 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
661 ** flag may be ORed in to indicate that only the data of the file
662 ** and not its inode needs to be synced.
663 **
664 ** The integer values to xLock() and xUnlock() are one of
665 ** <ul>
666 ** <li> [SQLITE_LOCK_NONE],
667 ** <li> [SQLITE_LOCK_SHARED],
668 ** <li> [SQLITE_LOCK_RESERVED],
669 ** <li> [SQLITE_LOCK_PENDING], or
670 ** <li> [SQLITE_LOCK_EXCLUSIVE].
671 ** </ul>
672 ** xLock() increases the lock. xUnlock() decreases the lock.
673 ** The xCheckReservedLock() method checks whether any database connection,
674 ** either in this process or in some other process, is holding a RESERVED,
675 ** PENDING, or EXCLUSIVE lock on the file. It returns true
676 ** if such a lock exists and false otherwise.
677 **
678 ** The xFileControl() method is a generic interface that allows custom
679 ** VFS implementations to directly control an open file using the
680 ** [sqlite3_file_control()] interface. The second "op" argument is an
681 ** integer opcode. The third argument is a generic pointer intended to
682 ** point to a structure that may contain arguments or space in which to
683 ** write return values. Potential uses for xFileControl() might be
684 ** functions to enable blocking locks with timeouts, to change the
685 ** locking strategy (for example to use dot-file locks), to inquire
686 ** about the status of a lock, or to break stale locks. The SQLite
687 ** core reserves all opcodes less than 100 for its own use.
688 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
689 ** Applications that define a custom xFileControl method should use opcodes
690 ** greater than 100 to avoid conflicts. VFS implementations should
691 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
692 ** recognize.
693 **
694 ** The xSectorSize() method returns the sector size of the
695 ** device that underlies the file. The sector size is the
696 ** minimum write that can be performed without disturbing
697 ** other bytes in the file. The xDeviceCharacteristics()
698 ** method returns a bit vector describing behaviors of the
699 ** underlying device:
700 **
701 ** <ul>
702 ** <li> [SQLITE_IOCAP_ATOMIC]
703 ** <li> [SQLITE_IOCAP_ATOMIC512]
704 ** <li> [SQLITE_IOCAP_ATOMIC1K]
705 ** <li> [SQLITE_IOCAP_ATOMIC2K]
706 ** <li> [SQLITE_IOCAP_ATOMIC4K]
707 ** <li> [SQLITE_IOCAP_ATOMIC8K]
708 ** <li> [SQLITE_IOCAP_ATOMIC16K]
709 ** <li> [SQLITE_IOCAP_ATOMIC32K]
710 ** <li> [SQLITE_IOCAP_ATOMIC64K]
711 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
712 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
713 ** </ul>
714 **
715 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
716 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
717 ** mean that writes of blocks that are nnn bytes in size and
718 ** are aligned to an address which is an integer multiple of
719 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
720 ** that when data is appended to a file, the data is appended
721 ** first then the size of the file is extended, never the other
722 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
723 ** information is written to disk in the same order as calls
724 ** to xWrite().
725 **
726 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
727 ** in the unread portions of the buffer with zeros. A VFS that
728 ** fails to zero-fill short reads might seem to work. However,
729 ** failure to zero-fill short reads will eventually lead to
730 ** database corruption.
731 */
732 typedef struct sqlite3_io_methods sqlite3_io_methods;
733 struct sqlite3_io_methods {
734 int iVersion;
735 int (*xClose)(sqlite3_file*);
736 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
737 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
738 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
739 int (*xSync)(sqlite3_file*, int flags);
740 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
741 int (*xLock)(sqlite3_file*, int);
742 int (*xUnlock)(sqlite3_file*, int);
743 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
744 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
745 int (*xSectorSize)(sqlite3_file*);
746 int (*xDeviceCharacteristics)(sqlite3_file*);
747 /* Methods above are valid for version 1 */
748 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
749 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
750 void (*xShmBarrier)(sqlite3_file*);
751 int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
752 /* Methods above are valid for version 2 */
753 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
754 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
755 /* Methods above are valid for version 3 */
756 /* Additional methods may be added in future releases */
757 };
758
759 /*
760 ** CAPI3REF: Standard File Control Opcodes
761 **
762 ** These integer constants are opcodes for the xFileControl method
763 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
764 ** interface.
765 **
766 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
767 ** opcode causes the xFileControl method to write the current state of
768 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
769 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
770 ** into an integer that the pArg argument points to. This capability
771 ** is used during testing and only needs to be supported when SQLITE_TEST
772 ** is defined.
773 ** <ul>
774 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
775 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
776 ** layer a hint of how large the database file will grow to be during the
777 ** current transaction. This hint is not guaranteed to be accurate but it
778 ** is often close. The underlying VFS might choose to preallocate database
779 ** file space based on this hint in order to help writes to the database
780 ** file run faster.
781 **
782 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
783 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
784 ** extends and truncates the database file in chunks of a size specified
785 ** by the user. The fourth argument to [sqlite3_file_control()] should
786 ** point to an integer (type int) containing the new chunk-size to use
787 ** for the nominated database. Allocating database file space in large
788 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
789 ** improve performance on some systems.
790 **
791 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
792 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
793 ** to the [sqlite3_file] object associated with a particular database
794 ** connection. See the [sqlite3_file_control()] documentation for
795 ** additional information.
796 **
797 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
798 ** No longer in use.
799 **
800 ** <li>[[SQLITE_FCNTL_SYNC]]
801 ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
802 ** sent to the VFS immediately before the xSync method is invoked on a
803 ** database file descriptor. Or, if the xSync method is not invoked
804 ** because the user has configured SQLite with
805 ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
806 ** of the xSync method. In most cases, the pointer argument passed with
807 ** this file-control is NULL. However, if the database file is being synced
808 ** as part of a multi-database commit, the argument points to a nul-terminated
809 ** string containing the transactions master-journal file name. VFSes that
810 ** do not need this signal should silently ignore this opcode. Applications
811 ** should not call [sqlite3_file_control()] with this opcode as doing so may
812 ** disrupt the operation of the specialized VFSes that do require it.
813 **
814 ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
815 ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
816 ** and sent to the VFS after a transaction has been committed immediately
817 ** but before the database is unlocked. VFSes that do not need this signal
818 ** should silently ignore this opcode. Applications should not call
819 ** [sqlite3_file_control()] with this opcode as doing so may disrupt the
820 ** operation of the specialized VFSes that do require it.
821 **
822 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
823 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
824 ** retry counts and intervals for certain disk I/O operations for the
825 ** windows [VFS] in order to provide robustness in the presence of
826 ** anti-virus programs. By default, the windows VFS will retry file read,
827 ** file write, and file delete operations up to 10 times, with a delay
828 ** of 25 milliseconds before the first retry and with the delay increasing
829 ** by an additional 25 milliseconds with each subsequent retry. This
830 ** opcode allows these two values (10 retries and 25 milliseconds of delay)
831 ** to be adjusted. The values are changed for all database connections
832 ** within the same process. The argument is a pointer to an array of two
833 ** integers where the first integer i the new retry count and the second
834 ** integer is the delay. If either integer is negative, then the setting
835 ** is not changed but instead the prior value of that setting is written
836 ** into the array entry, allowing the current retry settings to be
837 ** interrogated. The zDbName parameter is ignored.
838 **
839 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
840 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
841 ** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
842 ** write ahead log and shared memory files used for transaction control
843 ** are automatically deleted when the latest connection to the database
844 ** closes. Setting persistent WAL mode causes those files to persist after
845 ** close. Persisting the files is useful when other processes that do not
846 ** have write permission on the directory containing the database file want
847 ** to read the database file, as the WAL and shared memory files must exist
848 ** in order for the database to be readable. The fourth parameter to
849 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
850 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
851 ** WAL mode. If the integer is -1, then it is overwritten with the current
852 ** WAL persistence setting.
853 **
854 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
855 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
856 ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
857 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
858 ** xDeviceCharacteristics methods. The fourth parameter to
859 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
860 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
861 ** mode. If the integer is -1, then it is overwritten with the current
862 ** zero-damage mode setting.
863 **
864 ** <li>[[SQLITE_FCNTL_OVERWRITE]]
865 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
866 ** a write transaction to indicate that, unless it is rolled back for some
867 ** reason, the entire database file will be overwritten by the current
868 ** transaction. This is used by VACUUM operations.
869 **
870 ** <li>[[SQLITE_FCNTL_VFSNAME]]
871 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
872 ** all [VFSes] in the VFS stack. The names are of all VFS shims and the
873 ** final bottom-level VFS are written into memory obtained from
874 ** [sqlite3_malloc()] and the result is stored in the char* variable
875 ** that the fourth parameter of [sqlite3_file_control()] points to.
876 ** The caller is responsible for freeing the memory when done. As with
877 ** all file-control actions, there is no guarantee that this will actually
878 ** do anything. Callers should initialize the char* variable to a NULL
879 ** pointer in case this file-control is not implemented. This file-control
880 ** is intended for diagnostic use only.
881 **
882 ** <li>[[SQLITE_FCNTL_PRAGMA]]
883 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
884 ** file control is sent to the open [sqlite3_file] object corresponding
885 ** to the database file to which the pragma statement refers. ^The argument
886 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
887 ** pointers to strings (char**) in which the second element of the array
888 ** is the name of the pragma and the third element is the argument to the
889 ** pragma or NULL if the pragma has no argument. ^The handler for an
890 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
891 ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
892 ** or the equivalent and that string will become the result of the pragma or
893 ** the error message if the pragma fails. ^If the
894 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
895 ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
896 ** file control returns [SQLITE_OK], then the parser assumes that the
897 ** VFS has handled the PRAGMA itself and the parser generates a no-op
898 ** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns
899 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
900 ** that the VFS encountered an error while handling the [PRAGMA] and the
901 ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
902 ** file control occurs at the beginning of pragma statement analysis and so
903 ** it is able to override built-in [PRAGMA] statements.
904 **
905 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
906 ** ^The [SQLITE_FCNTL_BUSYHANDLER]
907 ** file-control may be invoked by SQLite on the database file handle
908 ** shortly after it is opened in order to provide a custom VFS with access
909 ** to the connections busy-handler callback. The argument is of type (void **)
910 ** - an array of two (void *) values. The first (void *) actually points
911 ** to a function of type (int (*)(void *)). In order to invoke the connections
912 ** busy-handler, this function should be invoked with the second (void *) in
913 ** the array as the only argument. If it returns non-zero, then the operation
914 ** should be retried. If it returns zero, the custom VFS should abandon the
915 ** current operation.
916 **
917 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
918 ** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
919 ** to have SQLite generate a
920 ** temporary filename using the same algorithm that is followed to generate
921 ** temporary filenames for TEMP tables and other internal uses. The
922 ** argument should be a char** which will be filled with the filename
923 ** written into memory obtained from [sqlite3_malloc()]. The caller should
924 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
925 **
926 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
927 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
928 ** maximum number of bytes that will be used for memory-mapped I/O.
929 ** The argument is a pointer to a value of type sqlite3_int64 that
930 ** is an advisory maximum number of bytes in the file to memory map. The
931 ** pointer is overwritten with the old value. The limit is not changed if
932 ** the value originally pointed to is negative, and so the current limit
933 ** can be queried by passing in a pointer to a negative number. This
934 ** file-control is used internally to implement [PRAGMA mmap_size].
935 **
936 ** <li>[[SQLITE_FCNTL_TRACE]]
937 ** The [SQLITE_FCNTL_TRACE] file control provides advisory information
938 ** to the VFS about what the higher layers of the SQLite stack are doing.
939 ** This file control is used by some VFS activity tracing [shims].
940 ** The argument is a zero-terminated string. Higher layers in the
941 ** SQLite stack may generate instances of this file control if
942 ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
943 **
944 ** <li>[[SQLITE_FCNTL_HAS_MOVED]]
945 ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
946 ** pointer to an integer and it writes a boolean into that integer depending
947 ** on whether or not the file has been renamed, moved, or deleted since it
948 ** was first opened.
949 **
950 ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
951 ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This
952 ** opcode causes the xFileControl method to swap the file handle with the one
953 ** pointed to by the pArg argument. This capability is used during testing
954 ** and only needs to be supported when SQLITE_TEST is defined.
955 **
956 ** </ul>
957 */
958 #define SQLITE_FCNTL_LOCKSTATE 1
959 #define SQLITE_GET_LOCKPROXYFILE 2
960 #define SQLITE_SET_LOCKPROXYFILE 3
961 #define SQLITE_LAST_ERRNO 4
962 #define SQLITE_FCNTL_SIZE_HINT 5
963 #define SQLITE_FCNTL_CHUNK_SIZE 6
964 #define SQLITE_FCNTL_FILE_POINTER 7
965 #define SQLITE_FCNTL_SYNC_OMITTED 8
966 #define SQLITE_FCNTL_WIN32_AV_RETRY 9
967 #define SQLITE_FCNTL_PERSIST_WAL 10
968 #define SQLITE_FCNTL_OVERWRITE 11
969 #define SQLITE_FCNTL_VFSNAME 12
970 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
971 #define SQLITE_FCNTL_PRAGMA 14
972 #define SQLITE_FCNTL_BUSYHANDLER 15
973 #define SQLITE_FCNTL_TEMPFILENAME 16
974 #define SQLITE_FCNTL_MMAP_SIZE 18
975 #define SQLITE_FCNTL_TRACE 19
976 #define SQLITE_FCNTL_HAS_MOVED 20
977 #define SQLITE_FCNTL_SYNC 21
978 #define SQLITE_FCNTL_COMMIT_PHASETWO 22
979 #define SQLITE_FCNTL_WIN32_SET_HANDLE 23
980
981 /*
982 ** CAPI3REF: Mutex Handle
983 **
984 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
985 ** abstract type for a mutex object. The SQLite core never looks
986 ** at the internal representation of an [sqlite3_mutex]. It only
987 ** deals with pointers to the [sqlite3_mutex] object.
988 **
989 ** Mutexes are created using [sqlite3_mutex_alloc()].
990 */
991 typedef struct sqlite3_mutex sqlite3_mutex;
992
993 /*
994 ** CAPI3REF: OS Interface Object
995 **
996 ** An instance of the sqlite3_vfs object defines the interface between
997 ** the SQLite core and the underlying operating system. The "vfs"
998 ** in the name of the object stands for "virtual file system". See
999 ** the [VFS | VFS documentation] for further information.
1000 **
1001 ** The value of the iVersion field is initially 1 but may be larger in
1002 ** future versions of SQLite. Additional fields may be appended to this
1003 ** object when the iVersion value is increased. Note that the structure
1004 ** of the sqlite3_vfs object changes in the transaction between
1005 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
1006 ** modified.
1007 **
1008 ** The szOsFile field is the size of the subclassed [sqlite3_file]
1009 ** structure used by this VFS. mxPathname is the maximum length of
1010 ** a pathname in this VFS.
1011 **
1012 ** Registered sqlite3_vfs objects are kept on a linked list formed by
1013 ** the pNext pointer. The [sqlite3_vfs_register()]
1014 ** and [sqlite3_vfs_unregister()] interfaces manage this list
1015 ** in a thread-safe way. The [sqlite3_vfs_find()] interface
1016 ** searches the list. Neither the application code nor the VFS
1017 ** implementation should use the pNext pointer.
1018 **
1019 ** The pNext field is the only field in the sqlite3_vfs
1020 ** structure that SQLite will ever modify. SQLite will only access
1021 ** or modify this field while holding a particular static mutex.
1022 ** The application should never modify anything within the sqlite3_vfs
1023 ** object once the object has been registered.
1024 **
1025 ** The zName field holds the name of the VFS module. The name must
1026 ** be unique across all VFS modules.
1027 **
1028 ** [[sqlite3_vfs.xOpen]]
1029 ** ^SQLite guarantees that the zFilename parameter to xOpen
1030 ** is either a NULL pointer or string obtained
1031 ** from xFullPathname() with an optional suffix added.
1032 ** ^If a suffix is added to the zFilename parameter, it will
1033 ** consist of a single "-" character followed by no more than
1034 ** 11 alphanumeric and/or "-" characters.
1035 ** ^SQLite further guarantees that
1036 ** the string will be valid and unchanged until xClose() is
1037 ** called. Because of the previous sentence,
1038 ** the [sqlite3_file] can safely store a pointer to the
1039 ** filename if it needs to remember the filename for some reason.
1040 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1041 ** must invent its own temporary name for the file. ^Whenever the
1042 ** xFilename parameter is NULL it will also be the case that the
1043 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1044 **
1045 ** The flags argument to xOpen() includes all bits set in
1046 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
1047 ** or [sqlite3_open16()] is used, then flags includes at least
1048 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1049 ** If xOpen() opens a file read-only then it sets *pOutFlags to
1050 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
1051 **
1052 ** ^(SQLite will also add one of the following flags to the xOpen()
1053 ** call, depending on the object being opened:
1054 **
1055 ** <ul>
1056 ** <li> [SQLITE_OPEN_MAIN_DB]
1057 ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
1058 ** <li> [SQLITE_OPEN_TEMP_DB]
1059 ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
1060 ** <li> [SQLITE_OPEN_TRANSIENT_DB]
1061 ** <li> [SQLITE_OPEN_SUBJOURNAL]
1062 ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
1063 ** <li> [SQLITE_OPEN_WAL]
1064 ** </ul>)^
1065 **
1066 ** The file I/O implementation can use the object type flags to
1067 ** change the way it deals with files. For example, an application
1068 ** that does not care about crash recovery or rollback might make
1069 ** the open of a journal file a no-op. Writes to this journal would
1070 ** also be no-ops, and any attempt to read the journal would return
1071 ** SQLITE_IOERR. Or the implementation might recognize that a database
1072 ** file will be doing page-aligned sector reads and writes in a random
1073 ** order and set up its I/O subsystem accordingly.
1074 **
1075 ** SQLite might also add one of the following flags to the xOpen method:
1076 **
1077 ** <ul>
1078 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
1079 ** <li> [SQLITE_OPEN_EXCLUSIVE]
1080 ** </ul>
1081 **
1082 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1083 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1084 ** will be set for TEMP databases and their journals, transient
1085 ** databases, and subjournals.
1086 **
1087 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1088 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1089 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1090 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1091 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1092 ** be created, and that it is an error if it already exists.
1093 ** It is <i>not</i> used to indicate the file should be opened
1094 ** for exclusive access.
1095 **
1096 ** ^At least szOsFile bytes of memory are allocated by SQLite
1097 ** to hold the [sqlite3_file] structure passed as the third
1098 ** argument to xOpen. The xOpen method does not have to
1099 ** allocate the structure; it should just fill it in. Note that
1100 ** the xOpen method must set the sqlite3_file.pMethods to either
1101 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1102 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1103 ** element will be valid after xOpen returns regardless of the success
1104 ** or failure of the xOpen call.
1105 **
1106 ** [[sqlite3_vfs.xAccess]]
1107 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1108 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1109 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1110 ** to test whether a file is at least readable. The file can be a
1111 ** directory.
1112 **
1113 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1114 ** output buffer xFullPathname. The exact size of the output buffer
1115 ** is also passed as a parameter to both methods. If the output buffer
1116 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1117 ** handled as a fatal error by SQLite, vfs implementations should endeavor
1118 ** to prevent this by setting mxPathname to a sufficiently large value.
1119 **
1120 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1121 ** interfaces are not strictly a part of the filesystem, but they are
1122 ** included in the VFS structure for completeness.
1123 ** The xRandomness() function attempts to return nBytes bytes
1124 ** of good-quality randomness into zOut. The return value is
1125 ** the actual number of bytes of randomness obtained.
1126 ** The xSleep() method causes the calling thread to sleep for at
1127 ** least the number of microseconds given. ^The xCurrentTime()
1128 ** method returns a Julian Day Number for the current date and time as
1129 ** a floating point value.
1130 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1131 ** Day Number multiplied by 86400000 (the number of milliseconds in
1132 ** a 24-hour day).
1133 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1134 ** date and time if that method is available (if iVersion is 2 or
1135 ** greater and the function pointer is not NULL) and will fall back
1136 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1137 **
1138 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1139 ** are not used by the SQLite core. These optional interfaces are provided
1140 ** by some VFSes to facilitate testing of the VFS code. By overriding
1141 ** system calls with functions under its control, a test program can
1142 ** simulate faults and error conditions that would otherwise be difficult
1143 ** or impossible to induce. The set of system calls that can be overridden
1144 ** varies from one VFS to another, and from one version of the same VFS to the
1145 ** next. Applications that use these interfaces must be prepared for any
1146 ** or all of these interfaces to be NULL or for their behavior to change
1147 ** from one release to the next. Applications must not attempt to access
1148 ** any of these methods if the iVersion of the VFS is less than 3.
1149 */
1150 typedef struct sqlite3_vfs sqlite3_vfs;
1151 typedef void (*sqlite3_syscall_ptr)(void);
1152 struct sqlite3_vfs {
1153 int iVersion; /* Structure version number (currently 3) */
1154 int szOsFile; /* Size of subclassed sqlite3_file */
1155 int mxPathname; /* Maximum file pathname length */
1156 sqlite3_vfs *pNext; /* Next registered VFS */
1157 const char *zName; /* Name of this virtual file system */
1158 void *pAppData; /* Pointer to application-specific data */
1159 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1160 int flags, int *pOutFlags);
1161 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1162 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1163 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1164 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1165 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1166 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1167 void (*xDlClose)(sqlite3_vfs*, void*);
1168 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1169 int (*xSleep)(sqlite3_vfs*, int microseconds);
1170 int (*xCurrentTime)(sqlite3_vfs*, double*);
1171 int (*xGetLastError)(sqlite3_vfs*, int, char *);
1172 /*
1173 ** The methods above are in version 1 of the sqlite_vfs object
1174 ** definition. Those that follow are added in version 2 or later
1175 */
1176 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1177 /*
1178 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1179 ** Those below are for version 3 and greater.
1180 */
1181 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1182 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1183 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1184 /*
1185 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1186 ** New fields may be appended in figure versions. The iVersion
1187 ** value will increment whenever this happens.
1188 */
1189 };
1190
1191 /*
1192 ** CAPI3REF: Flags for the xAccess VFS method
1193 **
1194 ** These integer constants can be used as the third parameter to
1195 ** the xAccess method of an [sqlite3_vfs] object. They determine
1196 ** what kind of permissions the xAccess method is looking for.
1197 ** With SQLITE_ACCESS_EXISTS, the xAccess method
1198 ** simply checks whether the file exists.
1199 ** With SQLITE_ACCESS_READWRITE, the xAccess method
1200 ** checks whether the named directory is both readable and writable
1201 ** (in other words, if files can be added, removed, and renamed within
1202 ** the directory).
1203 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1204 ** [temp_store_directory pragma], though this could change in a future
1205 ** release of SQLite.
1206 ** With SQLITE_ACCESS_READ, the xAccess method
1207 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1208 ** currently unused, though it might be used in a future release of
1209 ** SQLite.
1210 */
1211 #define SQLITE_ACCESS_EXISTS 0
1212 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1213 #define SQLITE_ACCESS_READ 2 /* Unused */
1214
1215 /*
1216 ** CAPI3REF: Flags for the xShmLock VFS method
1217 **
1218 ** These integer constants define the various locking operations
1219 ** allowed by the xShmLock method of [sqlite3_io_methods]. The
1220 ** following are the only legal combinations of flags to the
1221 ** xShmLock method:
1222 **
1223 ** <ul>
1224 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1225 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1226 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1227 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1228 ** </ul>
1229 **
1230 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1231 ** was given no the corresponding lock.
1232 **
1233 ** The xShmLock method can transition between unlocked and SHARED or
1234 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1235 ** and EXCLUSIVE.
1236 */
1237 #define SQLITE_SHM_UNLOCK 1
1238 #define SQLITE_SHM_LOCK 2
1239 #define SQLITE_SHM_SHARED 4
1240 #define SQLITE_SHM_EXCLUSIVE 8
1241
1242 /*
1243 ** CAPI3REF: Maximum xShmLock index
1244 **
1245 ** The xShmLock method on [sqlite3_io_methods] may use values
1246 ** between 0 and this upper bound as its "offset" argument.
1247 ** The SQLite core will never attempt to acquire or release a
1248 ** lock outside of this range
1249 */
1250 #define SQLITE_SHM_NLOCK 8
1251
1252
1253 /*
1254 ** CAPI3REF: Initialize The SQLite Library
1255 **
1256 ** ^The sqlite3_initialize() routine initializes the
1257 ** SQLite library. ^The sqlite3_shutdown() routine
1258 ** deallocates any resources that were allocated by sqlite3_initialize().
1259 ** These routines are designed to aid in process initialization and
1260 ** shutdown on embedded systems. Workstation applications using
1261 ** SQLite normally do not need to invoke either of these routines.
1262 **
1263 ** A call to sqlite3_initialize() is an "effective" call if it is
1264 ** the first time sqlite3_initialize() is invoked during the lifetime of
1265 ** the process, or if it is the first time sqlite3_initialize() is invoked
1266 ** following a call to sqlite3_shutdown(). ^(Only an effective call
1267 ** of sqlite3_initialize() does any initialization. All other calls
1268 ** are harmless no-ops.)^
1269 **
1270 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1271 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1272 ** an effective call to sqlite3_shutdown() does any deinitialization.
1273 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1274 **
1275 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1276 ** is not. The sqlite3_shutdown() interface must only be called from a
1277 ** single thread. All open [database connections] must be closed and all
1278 ** other SQLite resources must be deallocated prior to invoking
1279 ** sqlite3_shutdown().
1280 **
1281 ** Among other things, ^sqlite3_initialize() will invoke
1282 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1283 ** will invoke sqlite3_os_end().
1284 **
1285 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1286 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1287 ** the library (perhaps it is unable to allocate a needed resource such
1288 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1289 **
1290 ** ^The sqlite3_initialize() routine is called internally by many other
1291 ** SQLite interfaces so that an application usually does not need to
1292 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1293 ** calls sqlite3_initialize() so the SQLite library will be automatically
1294 ** initialized when [sqlite3_open()] is called if it has not be initialized
1295 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1296 ** compile-time option, then the automatic calls to sqlite3_initialize()
1297 ** are omitted and the application must call sqlite3_initialize() directly
1298 ** prior to using any other SQLite interface. For maximum portability,
1299 ** it is recommended that applications always invoke sqlite3_initialize()
1300 ** directly prior to using any other SQLite interface. Future releases
1301 ** of SQLite may require this. In other words, the behavior exhibited
1302 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1303 ** default behavior in some future release of SQLite.
1304 **
1305 ** The sqlite3_os_init() routine does operating-system specific
1306 ** initialization of the SQLite library. The sqlite3_os_end()
1307 ** routine undoes the effect of sqlite3_os_init(). Typical tasks
1308 ** performed by these routines include allocation or deallocation
1309 ** of static resources, initialization of global variables,
1310 ** setting up a default [sqlite3_vfs] module, or setting up
1311 ** a default configuration using [sqlite3_config()].
1312 **
1313 ** The application should never invoke either sqlite3_os_init()
1314 ** or sqlite3_os_end() directly. The application should only invoke
1315 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1316 ** interface is called automatically by sqlite3_initialize() and
1317 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1318 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1319 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1320 ** When [custom builds | built for other platforms]
1321 ** (using the [SQLITE_OS_OTHER=1] compile-time
1322 ** option) the application must supply a suitable implementation for
1323 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1324 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1325 ** must return [SQLITE_OK] on success and some other [error code] upon
1326 ** failure.
1327 */
1328 SQLITE_API int sqlite3_initialize(void);
1329 SQLITE_API int sqlite3_shutdown(void);
1330 SQLITE_API int sqlite3_os_init(void);
1331 SQLITE_API int sqlite3_os_end(void);
1332
1333 /*
1334 ** CAPI3REF: Configuring The SQLite Library
1335 **
1336 ** The sqlite3_config() interface is used to make global configuration
1337 ** changes to SQLite in order to tune SQLite to the specific needs of
1338 ** the application. The default configuration is recommended for most
1339 ** applications and so this routine is usually not necessary. It is
1340 ** provided to support rare applications with unusual needs.
1341 **
1342 ** The sqlite3_config() interface is not threadsafe. The application
1343 ** must insure that no other SQLite interfaces are invoked by other
1344 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config()
1345 ** may only be invoked prior to library initialization using
1346 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1347 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1348 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1349 ** Note, however, that ^sqlite3_config() can be called as part of the
1350 ** implementation of an application-defined [sqlite3_os_init()].
1351 **
1352 ** The first argument to sqlite3_config() is an integer
1353 ** [configuration option] that determines
1354 ** what property of SQLite is to be configured. Subsequent arguments
1355 ** vary depending on the [configuration option]
1356 ** in the first argument.
1357 **
1358 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1359 ** ^If the option is unknown or SQLite is unable to set the option
1360 ** then this routine returns a non-zero [error code].
1361 */
1362 SQLITE_API int sqlite3_config(int, ...);
1363
1364 /*
1365 ** CAPI3REF: Configure database connections
1366 **
1367 ** The sqlite3_db_config() interface is used to make configuration
1368 ** changes to a [database connection]. The interface is similar to
1369 ** [sqlite3_config()] except that the changes apply to a single
1370 ** [database connection] (specified in the first argument).
1371 **
1372 ** The second argument to sqlite3_db_config(D,V,...) is the
1373 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1374 ** that indicates what aspect of the [database connection] is being configured.
1375 ** Subsequent arguments vary depending on the configuration verb.
1376 **
1377 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1378 ** the call is considered successful.
1379 */
1380 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1381
1382 /*
1383 ** CAPI3REF: Memory Allocation Routines
1384 **
1385 ** An instance of this object defines the interface between SQLite
1386 ** and low-level memory allocation routines.
1387 **
1388 ** This object is used in only one place in the SQLite interface.
1389 ** A pointer to an instance of this object is the argument to
1390 ** [sqlite3_config()] when the configuration option is
1391 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1392 ** By creating an instance of this object
1393 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1394 ** during configuration, an application can specify an alternative
1395 ** memory allocation subsystem for SQLite to use for all of its
1396 ** dynamic memory needs.
1397 **
1398 ** Note that SQLite comes with several [built-in memory allocators]
1399 ** that are perfectly adequate for the overwhelming majority of applications
1400 ** and that this object is only useful to a tiny minority of applications
1401 ** with specialized memory allocation requirements. This object is
1402 ** also used during testing of SQLite in order to specify an alternative
1403 ** memory allocator that simulates memory out-of-memory conditions in
1404 ** order to verify that SQLite recovers gracefully from such
1405 ** conditions.
1406 **
1407 ** The xMalloc, xRealloc, and xFree methods must work like the
1408 ** malloc(), realloc() and free() functions from the standard C library.
1409 ** ^SQLite guarantees that the second argument to
1410 ** xRealloc is always a value returned by a prior call to xRoundup.
1411 **
1412 ** xSize should return the allocated size of a memory allocation
1413 ** previously obtained from xMalloc or xRealloc. The allocated size
1414 ** is always at least as big as the requested size but may be larger.
1415 **
1416 ** The xRoundup method returns what would be the allocated size of
1417 ** a memory allocation given a particular requested size. Most memory
1418 ** allocators round up memory allocations at least to the next multiple
1419 ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1420 ** Every memory allocation request coming in through [sqlite3_malloc()]
1421 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1422 ** that causes the corresponding memory allocation to fail.
1423 **
1424 ** The xInit method initializes the memory allocator. For example,
1425 ** it might allocate any require mutexes or initialize internal data
1426 ** structures. The xShutdown method is invoked (indirectly) by
1427 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1428 ** by xInit. The pAppData pointer is used as the only parameter to
1429 ** xInit and xShutdown.
1430 **
1431 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1432 ** the xInit method, so the xInit method need not be threadsafe. The
1433 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1434 ** not need to be threadsafe either. For all other methods, SQLite
1435 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1436 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1437 ** it is by default) and so the methods are automatically serialized.
1438 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1439 ** methods must be threadsafe or else make their own arrangements for
1440 ** serialization.
1441 **
1442 ** SQLite will never invoke xInit() more than once without an intervening
1443 ** call to xShutdown().
1444 */
1445 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1446 struct sqlite3_mem_methods {
1447 void *(*xMalloc)(int); /* Memory allocation function */
1448 void (*xFree)(void*); /* Free a prior allocation */
1449 void *(*xRealloc)(void*,int); /* Resize an allocation */
1450 int (*xSize)(void*); /* Return the size of an allocation */
1451 int (*xRoundup)(int); /* Round up request size to allocation size */
1452 int (*xInit)(void*); /* Initialize the memory allocator */
1453 void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1454 void *pAppData; /* Argument to xInit() and xShutdown() */
1455 };
1456
1457 /*
1458 ** CAPI3REF: Configuration Options
1459 ** KEYWORDS: {configuration option}
1460 **
1461 ** These constants are the available integer configuration options that
1462 ** can be passed as the first argument to the [sqlite3_config()] interface.
1463 **
1464 ** New configuration options may be added in future releases of SQLite.
1465 ** Existing configuration options might be discontinued. Applications
1466 ** should check the return code from [sqlite3_config()] to make sure that
1467 ** the call worked. The [sqlite3_config()] interface will return a
1468 ** non-zero [error code] if a discontinued or unsupported configuration option
1469 ** is invoked.
1470 **
1471 ** <dl>
1472 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1473 ** <dd>There are no arguments to this option. ^This option sets the
1474 ** [threading mode] to Single-thread. In other words, it disables
1475 ** all mutexing and puts SQLite into a mode where it can only be used
1476 ** by a single thread. ^If SQLite is compiled with
1477 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1478 ** it is not possible to change the [threading mode] from its default
1479 ** value of Single-thread and so [sqlite3_config()] will return
1480 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1481 ** configuration option.</dd>
1482 **
1483 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1484 ** <dd>There are no arguments to this option. ^This option sets the
1485 ** [threading mode] to Multi-thread. In other words, it disables
1486 ** mutexing on [database connection] and [prepared statement] objects.
1487 ** The application is responsible for serializing access to
1488 ** [database connections] and [prepared statements]. But other mutexes
1489 ** are enabled so that SQLite will be safe to use in a multi-threaded
1490 ** environment as long as no two threads attempt to use the same
1491 ** [database connection] at the same time. ^If SQLite is compiled with
1492 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1493 ** it is not possible to set the Multi-thread [threading mode] and
1494 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1495 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1496 **
1497 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1498 ** <dd>There are no arguments to this option. ^This option sets the
1499 ** [threading mode] to Serialized. In other words, this option enables
1500 ** all mutexes including the recursive
1501 ** mutexes on [database connection] and [prepared statement] objects.
1502 ** In this mode (which is the default when SQLite is compiled with
1503 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1504 ** to [database connections] and [prepared statements] so that the
1505 ** application is free to use the same [database connection] or the
1506 ** same [prepared statement] in different threads at the same time.
1507 ** ^If SQLite is compiled with
1508 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1509 ** it is not possible to set the Serialized [threading mode] and
1510 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1511 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1512 **
1513 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1514 ** <dd> ^(This option takes a single argument which is a pointer to an
1515 ** instance of the [sqlite3_mem_methods] structure. The argument specifies
1516 ** alternative low-level memory allocation routines to be used in place of
1517 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1518 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1519 ** before the [sqlite3_config()] call returns.</dd>
1520 **
1521 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1522 ** <dd> ^(This option takes a single argument which is a pointer to an
1523 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods]
1524 ** structure is filled with the currently defined memory allocation routines.)^
1525 ** This option can be used to overload the default memory allocation
1526 ** routines with a wrapper that simulations memory allocation failure or
1527 ** tracks memory usage, for example. </dd>
1528 **
1529 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1530 ** <dd> ^This option takes single argument of type int, interpreted as a
1531 ** boolean, which enables or disables the collection of memory allocation
1532 ** statistics. ^(When memory allocation statistics are disabled, the
1533 ** following SQLite interfaces become non-operational:
1534 ** <ul>
1535 ** <li> [sqlite3_memory_used()]
1536 ** <li> [sqlite3_memory_highwater()]
1537 ** <li> [sqlite3_soft_heap_limit64()]
1538 ** <li> [sqlite3_status()]
1539 ** </ul>)^
1540 ** ^Memory allocation statistics are enabled by default unless SQLite is
1541 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1542 ** allocation statistics are disabled by default.
1543 ** </dd>
1544 **
1545 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1546 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1547 ** scratch memory. There are three arguments: A pointer an 8-byte
1548 ** aligned memory buffer from which the scratch allocations will be
1549 ** drawn, the size of each scratch allocation (sz),
1550 ** and the maximum number of scratch allocations (N). The sz
1551 ** argument must be a multiple of 16.
1552 ** The first argument must be a pointer to an 8-byte aligned buffer
1553 ** of at least sz*N bytes of memory.
1554 ** ^SQLite will use no more than two scratch buffers per thread. So
1555 ** N should be set to twice the expected maximum number of threads.
1556 ** ^SQLite will never require a scratch buffer that is more than 6
1557 ** times the database page size. ^If SQLite needs needs additional
1558 ** scratch memory beyond what is provided by this configuration option, then
1559 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
1560 **
1561 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1562 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1563 ** the database page cache with the default page cache implementation.
1564 ** This configuration should not be used if an application-define page
1565 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option.
1566 ** There are three arguments to this option: A pointer to 8-byte aligned
1567 ** memory, the size of each page buffer (sz), and the number of pages (N).
1568 ** The sz argument should be the size of the largest database page
1569 ** (a power of two between 512 and 32768) plus a little extra for each
1570 ** page header. ^The page header size is 20 to 40 bytes depending on
1571 ** the host architecture. ^It is harmless, apart from the wasted memory,
1572 ** to make sz a little too large. The first
1573 ** argument should point to an allocation of at least sz*N bytes of memory.
1574 ** ^SQLite will use the memory provided by the first argument to satisfy its
1575 ** memory needs for the first N pages that it adds to cache. ^If additional
1576 ** page cache memory is needed beyond what is provided by this option, then
1577 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
1578 ** The pointer in the first argument must
1579 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite
1580 ** will be undefined.</dd>
1581 **
1582 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1583 ** <dd> ^This option specifies a static memory buffer that SQLite will use
1584 ** for all of its dynamic memory allocation needs beyond those provided
1585 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
1586 ** There are three arguments: An 8-byte aligned pointer to the memory,
1587 ** the number of bytes in the memory buffer, and the minimum allocation size.
1588 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1589 ** to using its default memory allocator (the system malloc() implementation),
1590 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1591 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
1592 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
1593 ** allocator is engaged to handle all of SQLites memory allocation needs.
1594 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1595 ** boundary or subsequent behavior of SQLite will be undefined.
1596 ** The minimum allocation size is capped at 2**12. Reasonable values
1597 ** for the minimum allocation size are 2**5 through 2**8.</dd>
1598 **
1599 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1600 ** <dd> ^(This option takes a single argument which is a pointer to an
1601 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies
1602 ** alternative low-level mutex routines to be used in place
1603 ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the
1604 ** content of the [sqlite3_mutex_methods] structure before the call to
1605 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1606 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1607 ** the entire mutexing subsystem is omitted from the build and hence calls to
1608 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1609 ** return [SQLITE_ERROR].</dd>
1610 **
1611 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1612 ** <dd> ^(This option takes a single argument which is a pointer to an
1613 ** instance of the [sqlite3_mutex_methods] structure. The
1614 ** [sqlite3_mutex_methods]
1615 ** structure is filled with the currently defined mutex routines.)^
1616 ** This option can be used to overload the default mutex allocation
1617 ** routines with a wrapper used to track mutex usage for performance
1618 ** profiling or testing, for example. ^If SQLite is compiled with
1619 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1620 ** the entire mutexing subsystem is omitted from the build and hence calls to
1621 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1622 ** return [SQLITE_ERROR].</dd>
1623 **
1624 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1625 ** <dd> ^(This option takes two arguments that determine the default
1626 ** memory allocation for the lookaside memory allocator on each
1627 ** [database connection]. The first argument is the
1628 ** size of each lookaside buffer slot and the second is the number of
1629 ** slots allocated to each database connection.)^ ^(This option sets the
1630 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1631 ** verb to [sqlite3_db_config()] can be used to change the lookaside
1632 ** configuration on individual connections.)^ </dd>
1633 **
1634 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1635 ** <dd> ^(This option takes a single argument which is a pointer to
1636 ** an [sqlite3_pcache_methods2] object. This object specifies the interface
1637 ** to a custom page cache implementation.)^ ^SQLite makes a copy of the
1638 ** object and uses it for page cache memory allocations.</dd>
1639 **
1640 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1641 ** <dd> ^(This option takes a single argument which is a pointer to an
1642 ** [sqlite3_pcache_methods2] object. SQLite copies of the current
1643 ** page cache implementation into that object.)^ </dd>
1644 **
1645 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1646 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1647 ** global [error log].
1648 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1649 ** function with a call signature of void(*)(void*,int,const char*),
1650 ** and a pointer to void. ^If the function pointer is not NULL, it is
1651 ** invoked by [sqlite3_log()] to process each logging event. ^If the
1652 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1653 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1654 ** passed through as the first parameter to the application-defined logger
1655 ** function whenever that function is invoked. ^The second parameter to
1656 ** the logger function is a copy of the first parameter to the corresponding
1657 ** [sqlite3_log()] call and is intended to be a [result code] or an
1658 ** [extended result code]. ^The third parameter passed to the logger is
1659 ** log message after formatting via [sqlite3_snprintf()].
1660 ** The SQLite logging interface is not reentrant; the logger function
1661 ** supplied by the application must not invoke any SQLite interface.
1662 ** In a multi-threaded application, the application-defined logger
1663 ** function must be threadsafe. </dd>
1664 **
1665 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1666 ** <dd>^(This option takes a single argument of type int. If non-zero, then
1667 ** URI handling is globally enabled. If the parameter is zero, then URI handling
1668 ** is globally disabled.)^ ^If URI handling is globally enabled, all filenames
1669 ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or
1670 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1671 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1672 ** connection is opened. ^If it is globally disabled, filenames are
1673 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1674 ** database connection is opened. ^(By default, URI handling is globally
1675 ** disabled. The default value may be changed by compiling with the
1676 ** [SQLITE_USE_URI] symbol defined.)^
1677 **
1678 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1679 ** <dd>^This option takes a single integer argument which is interpreted as
1680 ** a boolean in order to enable or disable the use of covering indices for
1681 ** full table scans in the query optimizer. ^The default setting is determined
1682 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1683 ** if that compile-time option is omitted.
1684 ** The ability to disable the use of covering indices for full table scans
1685 ** is because some incorrectly coded legacy applications might malfunction
1686 ** when the optimization is enabled. Providing the ability to
1687 ** disable the optimization allows the older, buggy application code to work
1688 ** without change even with newer versions of SQLite.
1689 **
1690 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1691 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1692 ** <dd> These options are obsolete and should not be used by new code.
1693 ** They are retained for backwards compatibility but are now no-ops.
1694 ** </dd>
1695 **
1696 ** [[SQLITE_CONFIG_SQLLOG]]
1697 ** <dt>SQLITE_CONFIG_SQLLOG
1698 ** <dd>This option is only available if sqlite is compiled with the
1699 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1700 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1701 ** The second should be of type (void*). The callback is invoked by the library
1702 ** in three separate circumstances, identified by the value passed as the
1703 ** fourth parameter. If the fourth parameter is 0, then the database connection
1704 ** passed as the second argument has just been opened. The third argument
1705 ** points to a buffer containing the name of the main database file. If the
1706 ** fourth parameter is 1, then the SQL statement that the third parameter
1707 ** points to has just been executed. Or, if the fourth parameter is 2, then
1708 ** the connection being passed as the second parameter is being closed. The
1709 ** third parameter is passed NULL In this case. An example of using this
1710 ** configuration option can be seen in the "test_sqllog.c" source file in
1711 ** the canonical SQLite source tree.</dd>
1712 **
1713 ** [[SQLITE_CONFIG_MMAP_SIZE]]
1714 ** <dt>SQLITE_CONFIG_MMAP_SIZE
1715 ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1716 ** that are the default mmap size limit (the default setting for
1717 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1718 ** ^The default setting can be overridden by each database connection using
1719 ** either the [PRAGMA mmap_size] command, or by using the
1720 ** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size
1721 ** cannot be changed at run-time. Nor may the maximum allowed mmap size
1722 ** exceed the compile-time maximum mmap size set by the
1723 ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1724 ** ^If either argument to this option is negative, then that argument is
1725 ** changed to its compile-time default.
1726 **
1727 ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
1728 ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
1729 ** <dd>^This option is only available if SQLite is compiled for Windows
1730 ** with the [SQLITE_WIN32_MALLOC] pre-processor macro defined.
1731 ** SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1732 ** that specifies the maximum size of the created heap.
1733 ** </dl>
1734 */
1735 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1736 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1737 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1738 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1739 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1740 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */
1741 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1742 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1743 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1744 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1745 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1746 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1747 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1748 #define SQLITE_CONFIG_PCACHE 14 /* no-op */
1749 #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
1750 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
1751 #define SQLITE_CONFIG_URI 17 /* int */
1752 #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
1753 #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
1754 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
1755 #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
1756 #define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
1757 #define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
1758
1759 /*
1760 ** CAPI3REF: Database Connection Configuration Options
1761 **
1762 ** These constants are the available integer configuration options that
1763 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1764 **
1765 ** New configuration options may be added in future releases of SQLite.
1766 ** Existing configuration options might be discontinued. Applications
1767 ** should check the return code from [sqlite3_db_config()] to make sure that
1768 ** the call worked. ^The [sqlite3_db_config()] interface will return a
1769 ** non-zero [error code] if a discontinued or unsupported configuration option
1770 ** is invoked.
1771 **
1772 ** <dl>
1773 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1774 ** <dd> ^This option takes three additional arguments that determine the
1775 ** [lookaside memory allocator] configuration for the [database connection].
1776 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1777 ** pointer to a memory buffer to use for lookaside memory.
1778 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1779 ** may be NULL in which case SQLite will allocate the
1780 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1781 ** size of each lookaside buffer slot. ^The third argument is the number of
1782 ** slots. The size of the buffer in the first argument must be greater than
1783 ** or equal to the product of the second and third arguments. The buffer
1784 ** must be aligned to an 8-byte boundary. ^If the second argument to
1785 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1786 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
1787 ** configuration for a database connection can only be changed when that
1788 ** connection is not currently using lookaside memory, or in other words
1789 ** when the "current value" returned by
1790 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1791 ** Any attempt to change the lookaside memory configuration when lookaside
1792 ** memory is in use leaves the configuration unchanged and returns
1793 ** [SQLITE_BUSY].)^</dd>
1794 **
1795 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1796 ** <dd> ^This option is used to enable or disable the enforcement of
1797 ** [foreign key constraints]. There should be two additional arguments.
1798 ** The first argument is an integer which is 0 to disable FK enforcement,
1799 ** positive to enable FK enforcement or negative to leave FK enforcement
1800 ** unchanged. The second parameter is a pointer to an integer into which
1801 ** is written 0 or 1 to indicate whether FK enforcement is off or on
1802 ** following this call. The second parameter may be a NULL pointer, in
1803 ** which case the FK enforcement setting is not reported back. </dd>
1804 **
1805 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1806 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1807 ** There should be two additional arguments.
1808 ** The first argument is an integer which is 0 to disable triggers,
1809 ** positive to enable triggers or negative to leave the setting unchanged.
1810 ** The second parameter is a pointer to an integer into which
1811 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
1812 ** following this call. The second parameter may be a NULL pointer, in
1813 ** which case the trigger setting is not reported back. </dd>
1814 **
1815 ** </dl>
1816 */
1817 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
1818 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
1819 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
1820
1821
1822 /*
1823 ** CAPI3REF: Enable Or Disable Extended Result Codes
1824 **
1825 ** ^The sqlite3_extended_result_codes() routine enables or disables the
1826 ** [extended result codes] feature of SQLite. ^The extended result
1827 ** codes are disabled by default for historical compatibility.
1828 */
1829 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
1830
1831 /*
1832 ** CAPI3REF: Last Insert Rowid
1833 **
1834 ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
1835 ** has a unique 64-bit signed
1836 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1837 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1838 ** names are not also used by explicitly declared columns. ^If
1839 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
1840 ** is another alias for the rowid.
1841 **
1842 ** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the
1843 ** most recent successful [INSERT] into a rowid table or [virtual table]
1844 ** on database connection D.
1845 ** ^Inserts into [WITHOUT ROWID] tables are not recorded.
1846 ** ^If no successful [INSERT]s into rowid tables
1847 ** have ever occurred on the database connection D,
1848 ** then sqlite3_last_insert_rowid(D) returns zero.
1849 **
1850 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
1851 ** method, then this routine will return the [rowid] of the inserted
1852 ** row as long as the trigger or virtual table method is running.
1853 ** But once the trigger or virtual table method ends, the value returned
1854 ** by this routine reverts to what it was before the trigger or virtual
1855 ** table method began.)^
1856 **
1857 ** ^An [INSERT] that fails due to a constraint violation is not a
1858 ** successful [INSERT] and does not change the value returned by this
1859 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1860 ** and INSERT OR ABORT make no changes to the return value of this
1861 ** routine when their insertion fails. ^(When INSERT OR REPLACE
1862 ** encounters a constraint violation, it does not fail. The
1863 ** INSERT continues to completion after deleting rows that caused
1864 ** the constraint problem so INSERT OR REPLACE will always change
1865 ** the return value of this interface.)^
1866 **
1867 ** ^For the purposes of this routine, an [INSERT] is considered to
1868 ** be successful even if it is subsequently rolled back.
1869 **
1870 ** This function is accessible to SQL statements via the
1871 ** [last_insert_rowid() SQL function].
1872 **
1873 ** If a separate thread performs a new [INSERT] on the same
1874 ** database connection while the [sqlite3_last_insert_rowid()]
1875 ** function is running and thus changes the last insert [rowid],
1876 ** then the value returned by [sqlite3_last_insert_rowid()] is
1877 ** unpredictable and might not equal either the old or the new
1878 ** last insert [rowid].
1879 */
1880 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
1881
1882 /*
1883 ** CAPI3REF: Count The Number Of Rows Modified
1884 **
1885 ** ^This function returns the number of database rows that were changed
1886 ** or inserted or deleted by the most recently completed SQL statement
1887 ** on the [database connection] specified by the first parameter.
1888 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
1889 ** or [DELETE] statement are counted. Auxiliary changes caused by
1890 ** triggers or [foreign key actions] are not counted.)^ Use the
1891 ** [sqlite3_total_changes()] function to find the total number of changes
1892 ** including changes caused by triggers and foreign key actions.
1893 **
1894 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
1895 ** are not counted. Only real table changes are counted.
1896 **
1897 ** ^(A "row change" is a change to a single row of a single table
1898 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that
1899 ** are changed as side effects of [REPLACE] constraint resolution,
1900 ** rollback, ABORT processing, [DROP TABLE], or by any other
1901 ** mechanisms do not count as direct row changes.)^
1902 **
1903 ** A "trigger context" is a scope of execution that begins and
1904 ** ends with the script of a [CREATE TRIGGER | trigger].
1905 ** Most SQL statements are
1906 ** evaluated outside of any trigger. This is the "top level"
1907 ** trigger context. If a trigger fires from the top level, a
1908 ** new trigger context is entered for the duration of that one
1909 ** trigger. Subtriggers create subcontexts for their duration.
1910 **
1911 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
1912 ** not create a new trigger context.
1913 **
1914 ** ^This function returns the number of direct row changes in the
1915 ** most recent INSERT, UPDATE, or DELETE statement within the same
1916 ** trigger context.
1917 **
1918 ** ^Thus, when called from the top level, this function returns the
1919 ** number of changes in the most recent INSERT, UPDATE, or DELETE
1920 ** that also occurred at the top level. ^(Within the body of a trigger,
1921 ** the sqlite3_changes() interface can be called to find the number of
1922 ** changes in the most recently completed INSERT, UPDATE, or DELETE
1923 ** statement within the body of the same trigger.
1924 ** However, the number returned does not include changes
1925 ** caused by subtriggers since those have their own context.)^
1926 **
1927 ** See also the [sqlite3_total_changes()] interface, the
1928 ** [count_changes pragma], and the [changes() SQL function].
1929 **
1930 ** If a separate thread makes changes on the same database connection
1931 ** while [sqlite3_changes()] is running then the value returned
1932 ** is unpredictable and not meaningful.
1933 */
1934 SQLITE_API int sqlite3_changes(sqlite3*);
1935
1936 /*
1937 ** CAPI3REF: Total Number Of Rows Modified
1938 **
1939 ** ^This function returns the number of row changes caused by [INSERT],
1940 ** [UPDATE] or [DELETE] statements since the [database connection] was opened.
1941 ** ^(The count returned by sqlite3_total_changes() includes all changes
1942 ** from all [CREATE TRIGGER | trigger] contexts and changes made by
1943 ** [foreign key actions]. However,
1944 ** the count does not include changes used to implement [REPLACE] constraints,
1945 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The
1946 ** count does not include rows of views that fire an [INSTEAD OF trigger],
1947 ** though if the INSTEAD OF trigger makes changes of its own, those changes
1948 ** are counted.)^
1949 ** ^The sqlite3_total_changes() function counts the changes as soon as
1950 ** the statement that makes them is completed (when the statement handle
1951 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
1952 **
1953 ** See also the [sqlite3_changes()] interface, the
1954 ** [count_changes pragma], and the [total_changes() SQL function].
1955 **
1956 ** If a separate thread makes changes on the same database connection
1957 ** while [sqlite3_total_changes()] is running then the value
1958 ** returned is unpredictable and not meaningful.
1959 */
1960 SQLITE_API int sqlite3_total_changes(sqlite3*);
1961
1962 /*
1963 ** CAPI3REF: Interrupt A Long-Running Query
1964 **
1965 ** ^This function causes any pending database operation to abort and
1966 ** return at its earliest opportunity. This routine is typically
1967 ** called in response to a user action such as pressing "Cancel"
1968 ** or Ctrl-C where the user wants a long query operation to halt
1969 ** immediately.
1970 **
1971 ** ^It is safe to call this routine from a thread different from the
1972 ** thread that is currently running the database operation. But it
1973 ** is not safe to call this routine with a [database connection] that
1974 ** is closed or might close before sqlite3_interrupt() returns.
1975 **
1976 ** ^If an SQL operation is very nearly finished at the time when
1977 ** sqlite3_interrupt() is called, then it might not have an opportunity
1978 ** to be interrupted and might continue to completion.
1979 **
1980 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
1981 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
1982 ** that is inside an explicit transaction, then the entire transaction
1983 ** will be rolled back automatically.
1984 **
1985 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
1986 ** SQL statements on [database connection] D complete. ^Any new SQL statements
1987 ** that are started after the sqlite3_interrupt() call and before the
1988 ** running statements reaches zero are interrupted as if they had been
1989 ** running prior to the sqlite3_interrupt() call. ^New SQL statements
1990 ** that are started after the running statement count reaches zero are
1991 ** not effected by the sqlite3_interrupt().
1992 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
1993 ** SQL statements is a no-op and has no effect on SQL statements
1994 ** that are started after the sqlite3_interrupt() call returns.
1995 **
1996 ** If the database connection closes while [sqlite3_interrupt()]
1997 ** is running then bad things will likely happen.
1998 */
1999 SQLITE_API void sqlite3_interrupt(sqlite3*);
2000
2001 /*
2002 ** CAPI3REF: Determine If An SQL Statement Is Complete
2003 **
2004 ** These routines are useful during command-line input to determine if the
2005 ** currently entered text seems to form a complete SQL statement or
2006 ** if additional input is needed before sending the text into
2007 ** SQLite for parsing. ^These routines return 1 if the input string
2008 ** appears to be a complete SQL statement. ^A statement is judged to be
2009 ** complete if it ends with a semicolon token and is not a prefix of a
2010 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
2011 ** string literals or quoted identifier names or comments are not
2012 ** independent tokens (they are part of the token in which they are
2013 ** embedded) and thus do not count as a statement terminator. ^Whitespace
2014 ** and comments that follow the final semicolon are ignored.
2015 **
2016 ** ^These routines return 0 if the statement is incomplete. ^If a
2017 ** memory allocation fails, then SQLITE_NOMEM is returned.
2018 **
2019 ** ^These routines do not parse the SQL statements thus
2020 ** will not detect syntactically incorrect SQL.
2021 **
2022 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2023 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2024 ** automatically by sqlite3_complete16(). If that initialization fails,
2025 ** then the return value from sqlite3_complete16() will be non-zero
2026 ** regardless of whether or not the input SQL is complete.)^
2027 **
2028 ** The input to [sqlite3_complete()] must be a zero-terminated
2029 ** UTF-8 string.
2030 **
2031 ** The input to [sqlite3_complete16()] must be a zero-terminated
2032 ** UTF-16 string in native byte order.
2033 */
2034 SQLITE_API int sqlite3_complete(const char *sql);
2035 SQLITE_API int sqlite3_complete16(const void *sql);
2036
2037 /*
2038 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2039 **
2040 ** ^This routine sets a callback function that might be invoked whenever
2041 ** an attempt is made to open a database table that another thread
2042 ** or process has locked.
2043 **
2044 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
2045 ** is returned immediately upon encountering the lock. ^If the busy callback
2046 ** is not NULL, then the callback might be invoked with two arguments.
2047 **
2048 ** ^The first argument to the busy handler is a copy of the void* pointer which
2049 ** is the third argument to sqlite3_busy_handler(). ^The second argument to
2050 ** the busy handler callback is the number of times that the busy handler has
2051 ** been invoked for this locking event. ^If the
2052 ** busy callback returns 0, then no additional attempts are made to
2053 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
2054 ** ^If the callback returns non-zero, then another attempt
2055 ** is made to open the database for reading and the cycle repeats.
2056 **
2057 ** The presence of a busy handler does not guarantee that it will be invoked
2058 ** when there is lock contention. ^If SQLite determines that invoking the busy
2059 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2060 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
2061 ** Consider a scenario where one process is holding a read lock that
2062 ** it is trying to promote to a reserved lock and
2063 ** a second process is holding a reserved lock that it is trying
2064 ** to promote to an exclusive lock. The first process cannot proceed
2065 ** because it is blocked by the second and the second process cannot
2066 ** proceed because it is blocked by the first. If both processes
2067 ** invoke the busy handlers, neither will make any progress. Therefore,
2068 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2069 ** will induce the first process to release its read lock and allow
2070 ** the second process to proceed.
2071 **
2072 ** ^The default busy callback is NULL.
2073 **
2074 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
2075 ** when SQLite is in the middle of a large transaction where all the
2076 ** changes will not fit into the in-memory cache. SQLite will
2077 ** already hold a RESERVED lock on the database file, but it needs
2078 ** to promote this lock to EXCLUSIVE so that it can spill cache
2079 ** pages into the database file without harm to concurrent
2080 ** readers. ^If it is unable to promote the lock, then the in-memory
2081 ** cache will be left in an inconsistent state and so the error
2082 ** code is promoted from the relatively benign [SQLITE_BUSY] to
2083 ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion
2084 ** forces an automatic rollback of the changes. See the
2085 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
2086 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
2087 ** this is important.
2088 **
2089 ** ^(There can only be a single busy handler defined for each
2090 ** [database connection]. Setting a new busy handler clears any
2091 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
2092 ** will also set or clear the busy handler.
2093 **
2094 ** The busy callback should not take any actions which modify the
2095 ** database connection that invoked the busy handler. Any such actions
2096 ** result in undefined behavior.
2097 **
2098 ** A busy handler must not close the database connection
2099 ** or [prepared statement] that invoked the busy handler.
2100 */
2101 SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
2102
2103 /*
2104 ** CAPI3REF: Set A Busy Timeout
2105 **
2106 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2107 ** for a specified amount of time when a table is locked. ^The handler
2108 ** will sleep multiple times until at least "ms" milliseconds of sleeping
2109 ** have accumulated. ^After at least "ms" milliseconds of sleeping,
2110 ** the handler returns 0 which causes [sqlite3_step()] to return
2111 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
2112 **
2113 ** ^Calling this routine with an argument less than or equal to zero
2114 ** turns off all busy handlers.
2115 **
2116 ** ^(There can only be a single busy handler for a particular
2117 ** [database connection] any any given moment. If another busy handler
2118 ** was defined (using [sqlite3_busy_handler()]) prior to calling
2119 ** this routine, that other busy handler is cleared.)^
2120 */
2121 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2122
2123 /*
2124 ** CAPI3REF: Convenience Routines For Running Queries
2125 **
2126 ** This is a legacy interface that is preserved for backwards compatibility.
2127 ** Use of this interface is not recommended.
2128 **
2129 ** Definition: A <b>result table</b> is memory data structure created by the
2130 ** [sqlite3_get_table()] interface. A result table records the
2131 ** complete query results from one or more queries.
2132 **
2133 ** The table conceptually has a number of rows and columns. But
2134 ** these numbers are not part of the result table itself. These
2135 ** numbers are obtained separately. Let N be the number of rows
2136 ** and M be the number of columns.
2137 **
2138 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2139 ** There are (N+1)*M elements in the array. The first M pointers point
2140 ** to zero-terminated strings that contain the names of the columns.
2141 ** The remaining entries all point to query results. NULL values result
2142 ** in NULL pointers. All other values are in their UTF-8 zero-terminated
2143 ** string representation as returned by [sqlite3_column_text()].
2144 **
2145 ** A result table might consist of one or more memory allocations.
2146 ** It is not safe to pass a result table directly to [sqlite3_free()].
2147 ** A result table should be deallocated using [sqlite3_free_table()].
2148 **
2149 ** ^(As an example of the result table format, suppose a query result
2150 ** is as follows:
2151 **
2152 ** <blockquote><pre>
2153 ** Name | Age
2154 ** -----------------------
2155 ** Alice | 43
2156 ** Bob | 28
2157 ** Cindy | 21
2158 ** </pre></blockquote>
2159 **
2160 ** There are two column (M==2) and three rows (N==3). Thus the
2161 ** result table has 8 entries. Suppose the result table is stored
2162 ** in an array names azResult. Then azResult holds this content:
2163 **
2164 ** <blockquote><pre>
2165 ** azResult&#91;0] = "Name";
2166 ** azResult&#91;1] = "Age";
2167 ** azResult&#91;2] = "Alice";
2168 ** azResult&#91;3] = "43";
2169 ** azResult&#91;4] = "Bob";
2170 ** azResult&#91;5] = "28";
2171 ** azResult&#91;6] = "Cindy";
2172 ** azResult&#91;7] = "21";
2173 ** </pre></blockquote>)^
2174 **
2175 ** ^The sqlite3_get_table() function evaluates one or more
2176 ** semicolon-separated SQL statements in the zero-terminated UTF-8
2177 ** string of its 2nd parameter and returns a result table to the
2178 ** pointer given in its 3rd parameter.
2179 **
2180 ** After the application has finished with the result from sqlite3_get_table(),
2181 ** it must pass the result table pointer to sqlite3_free_table() in order to
2182 ** release the memory that was malloced. Because of the way the
2183 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2184 ** function must not try to call [sqlite3_free()] directly. Only
2185 ** [sqlite3_free_table()] is able to release the memory properly and safely.
2186 **
2187 ** The sqlite3_get_table() interface is implemented as a wrapper around
2188 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
2189 ** to any internal data structures of SQLite. It uses only the public
2190 ** interface defined here. As a consequence, errors that occur in the
2191 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2192 ** reflected in subsequent calls to [sqlite3_errcode()] or
2193 ** [sqlite3_errmsg()].
2194 */
2195 SQLITE_API int sqlite3_get_table(
2196 sqlite3 *db, /* An open database */
2197 const char *zSql, /* SQL to be evaluated */
2198 char ***pazResult, /* Results of the query */
2199 int *pnRow, /* Number of result rows written here */
2200 int *pnColumn, /* Number of result columns written here */
2201 char **pzErrmsg /* Error msg written here */
2202 );
2203 SQLITE_API void sqlite3_free_table(char **result);
2204
2205 /*
2206 ** CAPI3REF: Formatted String Printing Functions
2207 **
2208 ** These routines are work-alikes of the "printf()" family of functions
2209 ** from the standard C library.
2210 **
2211 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2212 ** results into memory obtained from [sqlite3_malloc()].
2213 ** The strings returned by these two routines should be
2214 ** released by [sqlite3_free()]. ^Both routines return a
2215 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2216 ** memory to hold the resulting string.
2217 **
2218 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2219 ** the standard C library. The result is written into the
2220 ** buffer supplied as the second parameter whose size is given by
2221 ** the first parameter. Note that the order of the
2222 ** first two parameters is reversed from snprintf().)^ This is an
2223 ** historical accident that cannot be fixed without breaking
2224 ** backwards compatibility. ^(Note also that sqlite3_snprintf()
2225 ** returns a pointer to its buffer instead of the number of
2226 ** characters actually written into the buffer.)^ We admit that
2227 ** the number of characters written would be a more useful return
2228 ** value but we cannot change the implementation of sqlite3_snprintf()
2229 ** now without breaking compatibility.
2230 **
2231 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2232 ** guarantees that the buffer is always zero-terminated. ^The first
2233 ** parameter "n" is the total size of the buffer, including space for
2234 ** the zero terminator. So the longest string that can be completely
2235 ** written will be n-1 characters.
2236 **
2237 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2238 **
2239 ** These routines all implement some additional formatting
2240 ** options that are useful for constructing SQL statements.
2241 ** All of the usual printf() formatting options apply. In addition, there
2242 ** is are "%q", "%Q", and "%z" options.
2243 **
2244 ** ^(The %q option works like %s in that it substitutes a nul-terminated
2245 ** string from the argument list. But %q also doubles every '\'' character.
2246 ** %q is designed for use inside a string literal.)^ By doubling each '\''
2247 ** character it escapes that character and allows it to be inserted into
2248 ** the string.
2249 **
2250 ** For example, assume the string variable zText contains text as follows:
2251 **
2252 ** <blockquote><pre>
2253 ** char *zText = "It's a happy day!";
2254 ** </pre></blockquote>
2255 **
2256 ** One can use this text in an SQL statement as follows:
2257 **
2258 ** <blockquote><pre>
2259 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2260 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2261 ** sqlite3_free(zSQL);
2262 ** </pre></blockquote>
2263 **
2264 ** Because the %q format string is used, the '\'' character in zText
2265 ** is escaped and the SQL generated is as follows:
2266 **
2267 ** <blockquote><pre>
2268 ** INSERT INTO table1 VALUES('It''s a happy day!')
2269 ** </pre></blockquote>
2270 **
2271 ** This is correct. Had we used %s instead of %q, the generated SQL
2272 ** would have looked like this:
2273 **
2274 ** <blockquote><pre>
2275 ** INSERT INTO table1 VALUES('It's a happy day!');
2276 ** </pre></blockquote>
2277 **
2278 ** This second example is an SQL syntax error. As a general rule you should
2279 ** always use %q instead of %s when inserting text into a string literal.
2280 **
2281 ** ^(The %Q option works like %q except it also adds single quotes around
2282 ** the outside of the total string. Additionally, if the parameter in the
2283 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2284 ** single quotes).)^ So, for example, one could say:
2285 **
2286 ** <blockquote><pre>
2287 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2288 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2289 ** sqlite3_free(zSQL);
2290 ** </pre></blockquote>
2291 **
2292 ** The code above will render a correct SQL statement in the zSQL
2293 ** variable even if the zText variable is a NULL pointer.
2294 **
2295 ** ^(The "%z" formatting option works like "%s" but with the
2296 ** addition that after the string has been read and copied into
2297 ** the result, [sqlite3_free()] is called on the input string.)^
2298 */
2299 SQLITE_API char *sqlite3_mprintf(const char*,...);
2300 SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2301 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2302 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2303
2304 /*
2305 ** CAPI3REF: Memory Allocation Subsystem
2306 **
2307 ** The SQLite core uses these three routines for all of its own
2308 ** internal memory allocation needs. "Core" in the previous sentence
2309 ** does not include operating-system specific VFS implementation. The
2310 ** Windows VFS uses native malloc() and free() for some operations.
2311 **
2312 ** ^The sqlite3_malloc() routine returns a pointer to a block
2313 ** of memory at least N bytes in length, where N is the parameter.
2314 ** ^If sqlite3_malloc() is unable to obtain sufficient free
2315 ** memory, it returns a NULL pointer. ^If the parameter N to
2316 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2317 ** a NULL pointer.
2318 **
2319 ** ^Calling sqlite3_free() with a pointer previously returned
2320 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2321 ** that it might be reused. ^The sqlite3_free() routine is
2322 ** a no-op if is called with a NULL pointer. Passing a NULL pointer
2323 ** to sqlite3_free() is harmless. After being freed, memory
2324 ** should neither be read nor written. Even reading previously freed
2325 ** memory might result in a segmentation fault or other severe error.
2326 ** Memory corruption, a segmentation fault, or other severe error
2327 ** might result if sqlite3_free() is called with a non-NULL pointer that
2328 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2329 **
2330 ** ^(The sqlite3_realloc() interface attempts to resize a
2331 ** prior memory allocation to be at least N bytes, where N is the
2332 ** second parameter. The memory allocation to be resized is the first
2333 ** parameter.)^ ^ If the first parameter to sqlite3_realloc()
2334 ** is a NULL pointer then its behavior is identical to calling
2335 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
2336 ** ^If the second parameter to sqlite3_realloc() is zero or
2337 ** negative then the behavior is exactly the same as calling
2338 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
2339 ** ^sqlite3_realloc() returns a pointer to a memory allocation
2340 ** of at least N bytes in size or NULL if sufficient memory is unavailable.
2341 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2342 ** of the prior allocation are copied into the beginning of buffer returned
2343 ** by sqlite3_realloc() and the prior allocation is freed.
2344 ** ^If sqlite3_realloc() returns NULL, then the prior allocation
2345 ** is not freed.
2346 **
2347 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
2348 ** is always aligned to at least an 8 byte boundary, or to a
2349 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2350 ** option is used.
2351 **
2352 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2353 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2354 ** implementation of these routines to be omitted. That capability
2355 ** is no longer provided. Only built-in memory allocators can be used.
2356 **
2357 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2358 ** the system malloc() and free() directly when converting
2359 ** filenames between the UTF-8 encoding used by SQLite
2360 ** and whatever filename encoding is used by the particular Windows
2361 ** installation. Memory allocation errors were detected, but
2362 ** they were reported back as [SQLITE_CANTOPEN] or
2363 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2364 **
2365 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2366 ** must be either NULL or else pointers obtained from a prior
2367 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2368 ** not yet been released.
2369 **
2370 ** The application must not read or write any part of
2371 ** a block of memory after it has been released using
2372 ** [sqlite3_free()] or [sqlite3_realloc()].
2373 */
2374 SQLITE_API void *sqlite3_malloc(int);
2375 SQLITE_API void *sqlite3_realloc(void*, int);
2376 SQLITE_API void sqlite3_free(void*);
2377
2378 /*
2379 ** CAPI3REF: Memory Allocator Statistics
2380 **
2381 ** SQLite provides these two interfaces for reporting on the status
2382 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2383 ** routines, which form the built-in memory allocation subsystem.
2384 **
2385 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2386 ** of memory currently outstanding (malloced but not freed).
2387 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2388 ** value of [sqlite3_memory_used()] since the high-water mark
2389 ** was last reset. ^The values returned by [sqlite3_memory_used()] and
2390 ** [sqlite3_memory_highwater()] include any overhead
2391 ** added by SQLite in its implementation of [sqlite3_malloc()],
2392 ** but not overhead added by the any underlying system library
2393 ** routines that [sqlite3_malloc()] may call.
2394 **
2395 ** ^The memory high-water mark is reset to the current value of
2396 ** [sqlite3_memory_used()] if and only if the parameter to
2397 ** [sqlite3_memory_highwater()] is true. ^The value returned
2398 ** by [sqlite3_memory_highwater(1)] is the high-water mark
2399 ** prior to the reset.
2400 */
2401 SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2402 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2403
2404 /*
2405 ** CAPI3REF: Pseudo-Random Number Generator
2406 **
2407 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2408 ** select random [ROWID | ROWIDs] when inserting new records into a table that
2409 ** already uses the largest possible [ROWID]. The PRNG is also used for
2410 ** the build-in random() and randomblob() SQL functions. This interface allows
2411 ** applications to access the same PRNG for other purposes.
2412 **
2413 ** ^A call to this routine stores N bytes of randomness into buffer P.
2414 ** ^If N is less than one, then P can be a NULL pointer.
2415 **
2416 ** ^If this routine has not been previously called or if the previous
2417 ** call had N less than one, then the PRNG is seeded using randomness
2418 ** obtained from the xRandomness method of the default [sqlite3_vfs] object.
2419 ** ^If the previous call to this routine had an N of 1 or more then
2420 ** the pseudo-randomness is generated
2421 ** internally and without recourse to the [sqlite3_vfs] xRandomness
2422 ** method.
2423 */
2424 SQLITE_API void sqlite3_randomness(int N, void *P);
2425
2426 /*
2427 ** CAPI3REF: Compile-Time Authorization Callbacks
2428 **
2429 ** ^This routine registers an authorizer callback with a particular
2430 ** [database connection], supplied in the first argument.
2431 ** ^The authorizer callback is invoked as SQL statements are being compiled
2432 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2433 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various
2434 ** points during the compilation process, as logic is being created
2435 ** to perform various actions, the authorizer callback is invoked to
2436 ** see if those actions are allowed. ^The authorizer callback should
2437 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2438 ** specific action but allow the SQL statement to continue to be
2439 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2440 ** rejected with an error. ^If the authorizer callback returns
2441 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2442 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2443 ** the authorizer will fail with an error message.
2444 **
2445 ** When the callback returns [SQLITE_OK], that means the operation
2446 ** requested is ok. ^When the callback returns [SQLITE_DENY], the
2447 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2448 ** authorizer will fail with an error message explaining that
2449 ** access is denied.
2450 **
2451 ** ^The first parameter to the authorizer callback is a copy of the third
2452 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2453 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2454 ** the particular action to be authorized. ^The third through sixth parameters
2455 ** to the callback are zero-terminated strings that contain additional
2456 ** details about the action to be authorized.
2457 **
2458 ** ^If the action code is [SQLITE_READ]
2459 ** and the callback returns [SQLITE_IGNORE] then the
2460 ** [prepared statement] statement is constructed to substitute
2461 ** a NULL value in place of the table column that would have
2462 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2463 ** return can be used to deny an untrusted user access to individual
2464 ** columns of a table.
2465 ** ^If the action code is [SQLITE_DELETE] and the callback returns
2466 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2467 ** [truncate optimization] is disabled and all rows are deleted individually.
2468 **
2469 ** An authorizer is used when [sqlite3_prepare | preparing]
2470 ** SQL statements from an untrusted source, to ensure that the SQL statements
2471 ** do not try to access data they are not allowed to see, or that they do not
2472 ** try to execute malicious statements that damage the database. For
2473 ** example, an application may allow a user to enter arbitrary
2474 ** SQL queries for evaluation by a database. But the application does
2475 ** not want the user to be able to make arbitrary changes to the
2476 ** database. An authorizer could then be put in place while the
2477 ** user-entered SQL is being [sqlite3_prepare | prepared] that
2478 ** disallows everything except [SELECT] statements.
2479 **
2480 ** Applications that need to process SQL from untrusted sources
2481 ** might also consider lowering resource limits using [sqlite3_limit()]
2482 ** and limiting database size using the [max_page_count] [PRAGMA]
2483 ** in addition to using an authorizer.
2484 **
2485 ** ^(Only a single authorizer can be in place on a database connection
2486 ** at a time. Each call to sqlite3_set_authorizer overrides the
2487 ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2488 ** The authorizer is disabled by default.
2489 **
2490 ** The authorizer callback must not do anything that will modify
2491 ** the database connection that invoked the authorizer callback.
2492 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2493 ** database connections for the meaning of "modify" in this paragraph.
2494 **
2495 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2496 ** statement might be re-prepared during [sqlite3_step()] due to a
2497 ** schema change. Hence, the application should ensure that the
2498 ** correct authorizer callback remains in place during the [sqlite3_step()].
2499 **
2500 ** ^Note that the authorizer callback is invoked only during
2501 ** [sqlite3_prepare()] or its variants. Authorization is not
2502 ** performed during statement evaluation in [sqlite3_step()], unless
2503 ** as stated in the previous paragraph, sqlite3_step() invokes
2504 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2505 */
2506 SQLITE_API int sqlite3_set_authorizer(
2507 sqlite3*,
2508 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2509 void *pUserData
2510 );
2511
2512 /*
2513 ** CAPI3REF: Authorizer Return Codes
2514 **
2515 ** The [sqlite3_set_authorizer | authorizer callback function] must
2516 ** return either [SQLITE_OK] or one of these two constants in order
2517 ** to signal SQLite whether or not the action is permitted. See the
2518 ** [sqlite3_set_authorizer | authorizer documentation] for additional
2519 ** information.
2520 **
2521 ** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code]
2522 ** from the [sqlite3_vtab_on_conflict()] interface.
2523 */
2524 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */
2525 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
2526
2527 /*
2528 ** CAPI3REF: Authorizer Action Codes
2529 **
2530 ** The [sqlite3_set_authorizer()] interface registers a callback function
2531 ** that is invoked to authorize certain SQL statement actions. The
2532 ** second parameter to the callback is an integer code that specifies
2533 ** what action is being authorized. These are the integer action codes that
2534 ** the authorizer callback may be passed.
2535 **
2536 ** These action code values signify what kind of operation is to be
2537 ** authorized. The 3rd and 4th parameters to the authorization
2538 ** callback function will be parameters or NULL depending on which of these
2539 ** codes is used as the second parameter. ^(The 5th parameter to the
2540 ** authorizer callback is the name of the database ("main", "temp",
2541 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2542 ** is the name of the inner-most trigger or view that is responsible for
2543 ** the access attempt or NULL if this access attempt is directly from
2544 ** top-level SQL code.
2545 */
2546 /******************************************* 3rd ************ 4th ***********/
2547 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
2548 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
2549 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
2550 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
2551 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
2552 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
2553 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2554 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2555 #define SQLITE_DELETE 9 /* Table Name NULL */
2556 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2557 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2558 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2559 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2560 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2561 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2562 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2563 #define SQLITE_DROP_VIEW 17 /* View Name NULL */
2564 #define SQLITE_INSERT 18 /* Table Name NULL */
2565 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2566 #define SQLITE_READ 20 /* Table Name Column Name */
2567 #define SQLITE_SELECT 21 /* NULL NULL */
2568 #define SQLITE_TRANSACTION 22 /* Operation NULL */
2569 #define SQLITE_UPDATE 23 /* Table Name Column Name */
2570 #define SQLITE_ATTACH 24 /* Filename NULL */
2571 #define SQLITE_DETACH 25 /* Database Name NULL */
2572 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2573 #define SQLITE_REINDEX 27 /* Index Name NULL */
2574 #define SQLITE_ANALYZE 28 /* Table Name NULL */
2575 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2576 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2577 #define SQLITE_FUNCTION 31 /* NULL Function Name */
2578 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2579 #define SQLITE_COPY 0 /* No longer used */
2580 #define SQLITE_RECURSIVE 33 /* NULL NULL */
2581
2582 /*
2583 ** CAPI3REF: Tracing And Profiling Functions
2584 **
2585 ** These routines register callback functions that can be used for
2586 ** tracing and profiling the execution of SQL statements.
2587 **
2588 ** ^The callback function registered by sqlite3_trace() is invoked at
2589 ** various times when an SQL statement is being run by [sqlite3_step()].
2590 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2591 ** SQL statement text as the statement first begins executing.
2592 ** ^(Additional sqlite3_trace() callbacks might occur
2593 ** as each triggered subprogram is entered. The callbacks for triggers
2594 ** contain a UTF-8 SQL comment that identifies the trigger.)^
2595 **
2596 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2597 ** the length of [bound parameter] expansion in the output of sqlite3_trace().
2598 **
2599 ** ^The callback function registered by sqlite3_profile() is invoked
2600 ** as each SQL statement finishes. ^The profile callback contains
2601 ** the original statement text and an estimate of wall-clock time
2602 ** of how long that statement took to run. ^The profile callback
2603 ** time is in units of nanoseconds, however the current implementation
2604 ** is only capable of millisecond resolution so the six least significant
2605 ** digits in the time are meaningless. Future versions of SQLite
2606 ** might provide greater resolution on the profiler callback. The
2607 ** sqlite3_profile() function is considered experimental and is
2608 ** subject to change in future versions of SQLite.
2609 */
2610 SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2611 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
2612 void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2613
2614 /*
2615 ** CAPI3REF: Query Progress Callbacks
2616 **
2617 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2618 ** function X to be invoked periodically during long running calls to
2619 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2620 ** database connection D. An example use for this
2621 ** interface is to keep a GUI updated during a large query.
2622 **
2623 ** ^The parameter P is passed through as the only parameter to the
2624 ** callback function X. ^The parameter N is the approximate number of
2625 ** [virtual machine instructions] that are evaluated between successive
2626 ** invocations of the callback X. ^If N is less than one then the progress
2627 ** handler is disabled.
2628 **
2629 ** ^Only a single progress handler may be defined at one time per
2630 ** [database connection]; setting a new progress handler cancels the
2631 ** old one. ^Setting parameter X to NULL disables the progress handler.
2632 ** ^The progress handler is also disabled by setting N to a value less
2633 ** than 1.
2634 **
2635 ** ^If the progress callback returns non-zero, the operation is
2636 ** interrupted. This feature can be used to implement a
2637 ** "Cancel" button on a GUI progress dialog box.
2638 **
2639 ** The progress handler callback must not do anything that will modify
2640 ** the database connection that invoked the progress handler.
2641 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2642 ** database connections for the meaning of "modify" in this paragraph.
2643 **
2644 */
2645 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2646
2647 /*
2648 ** CAPI3REF: Opening A New Database Connection
2649 **
2650 ** ^These routines open an SQLite database file as specified by the
2651 ** filename argument. ^The filename argument is interpreted as UTF-8 for
2652 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2653 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
2654 ** returned in *ppDb, even if an error occurs. The only exception is that
2655 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2656 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2657 ** object.)^ ^(If the database is opened (and/or created) successfully, then
2658 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
2659 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2660 ** an English language description of the error following a failure of any
2661 ** of the sqlite3_open() routines.
2662 **
2663 ** ^The default encoding for the database will be UTF-8 if
2664 ** sqlite3_open() or sqlite3_open_v2() is called and
2665 ** UTF-16 in the native byte order if sqlite3_open16() is used.
2666 **
2667 ** Whether or not an error occurs when it is opened, resources
2668 ** associated with the [database connection] handle should be released by
2669 ** passing it to [sqlite3_close()] when it is no longer required.
2670 **
2671 ** The sqlite3_open_v2() interface works like sqlite3_open()
2672 ** except that it accepts two additional parameters for additional control
2673 ** over the new database connection. ^(The flags parameter to
2674 ** sqlite3_open_v2() can take one of
2675 ** the following three values, optionally combined with the
2676 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2677 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
2678 **
2679 ** <dl>
2680 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2681 ** <dd>The database is opened in read-only mode. If the database does not
2682 ** already exist, an error is returned.</dd>)^
2683 **
2684 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2685 ** <dd>The database is opened for reading and writing if possible, or reading
2686 ** only if the file is write protected by the operating system. In either
2687 ** case the database must already exist, otherwise an error is returned.</dd>)^
2688 **
2689 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2690 ** <dd>The database is opened for reading and writing, and is created if
2691 ** it does not already exist. This is the behavior that is always used for
2692 ** sqlite3_open() and sqlite3_open16().</dd>)^
2693 ** </dl>
2694 **
2695 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
2696 ** combinations shown above optionally combined with other
2697 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
2698 ** then the behavior is undefined.
2699 **
2700 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2701 ** opens in the multi-thread [threading mode] as long as the single-thread
2702 ** mode has not been set at compile-time or start-time. ^If the
2703 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2704 ** in the serialized [threading mode] unless single-thread was
2705 ** previously selected at compile-time or start-time.
2706 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2707 ** eligible to use [shared cache mode], regardless of whether or not shared
2708 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
2709 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2710 ** participate in [shared cache mode] even if it is enabled.
2711 **
2712 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
2713 ** [sqlite3_vfs] object that defines the operating system interface that
2714 ** the new database connection should use. ^If the fourth parameter is
2715 ** a NULL pointer then the default [sqlite3_vfs] object is used.
2716 **
2717 ** ^If the filename is ":memory:", then a private, temporary in-memory database
2718 ** is created for the connection. ^This in-memory database will vanish when
2719 ** the database connection is closed. Future versions of SQLite might
2720 ** make use of additional special filenames that begin with the ":" character.
2721 ** It is recommended that when a database filename actually does begin with
2722 ** a ":" character you should prefix the filename with a pathname such as
2723 ** "./" to avoid ambiguity.
2724 **
2725 ** ^If the filename is an empty string, then a private, temporary
2726 ** on-disk database will be created. ^This private database will be
2727 ** automatically deleted as soon as the database connection is closed.
2728 **
2729 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
2730 **
2731 ** ^If [URI filename] interpretation is enabled, and the filename argument
2732 ** begins with "file:", then the filename is interpreted as a URI. ^URI
2733 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
2734 ** set in the fourth argument to sqlite3_open_v2(), or if it has
2735 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
2736 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
2737 ** As of SQLite version 3.7.7, URI filename interpretation is turned off
2738 ** by default, but future releases of SQLite might enable URI filename
2739 ** interpretation by default. See "[URI filenames]" for additional
2740 ** information.
2741 **
2742 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
2743 ** authority, then it must be either an empty string or the string
2744 ** "localhost". ^If the authority is not an empty string or "localhost", an
2745 ** error is returned to the caller. ^The fragment component of a URI, if
2746 ** present, is ignored.
2747 **
2748 ** ^SQLite uses the path component of the URI as the name of the disk file
2749 ** which contains the database. ^If the path begins with a '/' character,
2750 ** then it is interpreted as an absolute path. ^If the path does not begin
2751 ** with a '/' (meaning that the authority section is omitted from the URI)
2752 ** then the path is interpreted as a relative path.
2753 ** ^On windows, the first component of an absolute path
2754 ** is a drive specification (e.g. "C:").
2755 **
2756 ** [[core URI query parameters]]
2757 ** The query component of a URI may contain parameters that are interpreted
2758 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
2759 ** SQLite interprets the following three query parameters:
2760 **
2761 ** <ul>
2762 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
2763 ** a VFS object that provides the operating system interface that should
2764 ** be used to access the database file on disk. ^If this option is set to
2765 ** an empty string the default VFS object is used. ^Specifying an unknown
2766 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
2767 ** present, then the VFS specified by the option takes precedence over
2768 ** the value passed as the fourth parameter to sqlite3_open_v2().
2769 **
2770 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
2771 ** "rwc", or "memory". Attempting to set it to any other value is
2772 ** an error)^.
2773 ** ^If "ro" is specified, then the database is opened for read-only
2774 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
2775 ** third argument to sqlite3_open_v2(). ^If the mode option is set to
2776 ** "rw", then the database is opened for read-write (but not create)
2777 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
2778 ** been set. ^Value "rwc" is equivalent to setting both
2779 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
2780 ** set to "memory" then a pure [in-memory database] that never reads
2781 ** or writes from disk is used. ^It is an error to specify a value for
2782 ** the mode parameter that is less restrictive than that specified by
2783 ** the flags passed in the third parameter to sqlite3_open_v2().
2784 **
2785 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
2786 ** "private". ^Setting it to "shared" is equivalent to setting the
2787 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
2788 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
2789 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
2790 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
2791 ** a URI filename, its value overrides any behavior requested by setting
2792 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
2793 **
2794 ** <li> <b>psow</b>: ^The psow parameter may be "true" (or "on" or "yes" or
2795 ** "1") or "false" (or "off" or "no" or "0") to indicate that the
2796 ** [powersafe overwrite] property does or does not apply to the
2797 ** storage media on which the database file resides. ^The psow query
2798 ** parameter only works for the built-in unix and Windows VFSes.
2799 **
2800 ** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
2801 ** which if set disables file locking in rollback journal modes. This
2802 ** is useful for accessing a database on a filesystem that does not
2803 ** support locking. Caution: Database corruption might result if two
2804 ** or more processes write to the same database and any one of those
2805 ** processes uses nolock=1.
2806 **
2807 ** <li> <b>immutable</b>: ^The immutable parameter is a boolean query
2808 ** parameter that indicates that the database file is stored on
2809 ** read-only media. ^When immutable is set, SQLite assumes that the
2810 ** database file cannot be changed, even by a process with higher
2811 ** privilege, and so the database is opened read-only and all locking
2812 ** and change detection is disabled. Caution: Setting the immutable
2813 ** property on a database file that does in fact change can result
2814 ** in incorrect query results and/or [SQLITE_CORRUPT] errors.
2815 ** See also: [SQLITE_IOCAP_IMMUTABLE].
2816 **
2817 ** </ul>
2818 **
2819 ** ^Specifying an unknown parameter in the query component of a URI is not an
2820 ** error. Future versions of SQLite might understand additional query
2821 ** parameters. See "[query parameters with special meaning to SQLite]" for
2822 ** additional information.
2823 **
2824 ** [[URI filename examples]] <h3>URI filename examples</h3>
2825 **
2826 ** <table border="1" align=center cellpadding=5>
2827 ** <tr><th> URI filenames <th> Results
2828 ** <tr><td> file:data.db <td>
2829 ** Open the file "data.db" in the current directory.
2830 ** <tr><td> file:/home/fred/data.db<br>
2831 ** file:///home/fred/data.db <br>
2832 ** file://localhost/home/fred/data.db <br> <td>
2833 ** Open the database file "/home/fred/data.db".
2834 ** <tr><td> file://darkstar/home/fred/data.db <td>
2835 ** An error. "darkstar" is not a recognized authority.
2836 ** <tr><td style="white-space:nowrap">
2837 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
2838 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive
2839 ** C:. Note that the %20 escaping in this example is not strictly
2840 ** necessary - space characters can be used literally
2841 ** in URI filenames.
2842 ** <tr><td> file:data.db?mode=ro&cache=private <td>
2843 ** Open file "data.db" in the current directory for read-only access.
2844 ** Regardless of whether or not shared-cache mode is enabled by
2845 ** default, use a private cache.
2846 ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
2847 ** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
2848 ** that uses dot-files in place of posix advisory locking.
2849 ** <tr><td> file:data.db?mode=readonly <td>
2850 ** An error. "readonly" is not a valid option for the "mode" parameter.
2851 ** </table>
2852 **
2853 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
2854 ** query components of a URI. A hexadecimal escape sequence consists of a
2855 ** percent sign - "%" - followed by exactly two hexadecimal digits
2856 ** specifying an octet value. ^Before the path or query components of a
2857 ** URI filename are interpreted, they are encoded using UTF-8 and all
2858 ** hexadecimal escape sequences replaced by a single byte containing the
2859 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
2860 ** the results are undefined.
2861 **
2862 ** <b>Note to Windows users:</b> The encoding used for the filename argument
2863 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2864 ** codepage is currently defined. Filenames containing international
2865 ** characters must be converted to UTF-8 prior to passing them into
2866 ** sqlite3_open() or sqlite3_open_v2().
2867 **
2868 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
2869 ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
2870 ** features that require the use of temporary files may fail.
2871 **
2872 ** See also: [sqlite3_temp_directory]
2873 */
2874 SQLITE_API int sqlite3_open(
2875 const char *filename, /* Database filename (UTF-8) */
2876 sqlite3 **ppDb /* OUT: SQLite db handle */
2877 );
2878 SQLITE_API int sqlite3_open16(
2879 const void *filename, /* Database filename (UTF-16) */
2880 sqlite3 **ppDb /* OUT: SQLite db handle */
2881 );
2882 SQLITE_API int sqlite3_open_v2(
2883 const char *filename, /* Database filename (UTF-8) */
2884 sqlite3 **ppDb, /* OUT: SQLite db handle */
2885 int flags, /* Flags */
2886 const char *zVfs /* Name of VFS module to use */
2887 );
2888
2889 /*
2890 ** CAPI3REF: Obtain Values For URI Parameters
2891 **
2892 ** These are utility routines, useful to VFS implementations, that check
2893 ** to see if a database file was a URI that contained a specific query
2894 ** parameter, and if so obtains the value of that query parameter.
2895 **
2896 ** If F is the database filename pointer passed into the xOpen() method of
2897 ** a VFS implementation when the flags parameter to xOpen() has one or
2898 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
2899 ** P is the name of the query parameter, then
2900 ** sqlite3_uri_parameter(F,P) returns the value of the P
2901 ** parameter if it exists or a NULL pointer if P does not appear as a
2902 ** query parameter on F. If P is a query parameter of F
2903 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
2904 ** a pointer to an empty string.
2905 **
2906 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
2907 ** parameter and returns true (1) or false (0) according to the value
2908 ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
2909 ** value of query parameter P is one of "yes", "true", or "on" in any
2910 ** case or if the value begins with a non-zero number. The
2911 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
2912 ** query parameter P is one of "no", "false", or "off" in any case or
2913 ** if the value begins with a numeric zero. If P is not a query
2914 ** parameter on F or if the value of P is does not match any of the
2915 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
2916 **
2917 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
2918 ** 64-bit signed integer and returns that integer, or D if P does not
2919 ** exist. If the value of P is something other than an integer, then
2920 ** zero is returned.
2921 **
2922 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
2923 ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
2924 ** is not a database file pathname pointer that SQLite passed into the xOpen
2925 ** VFS method, then the behavior of this routine is undefined and probably
2926 ** undesirable.
2927 */
2928 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
2929 SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
2930 SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
2931
2932
2933 /*
2934 ** CAPI3REF: Error Codes And Messages
2935 **
2936 ** ^The sqlite3_errcode() interface returns the numeric [result code] or
2937 ** [extended result code] for the most recent failed sqlite3_* API call
2938 ** associated with a [database connection]. If a prior API call failed
2939 ** but the most recent API call succeeded, the return value from
2940 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode()
2941 ** interface is the same except that it always returns the
2942 ** [extended result code] even when extended result codes are
2943 ** disabled.
2944 **
2945 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
2946 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
2947 ** ^(Memory to hold the error message string is managed internally.
2948 ** The application does not need to worry about freeing the result.
2949 ** However, the error string might be overwritten or deallocated by
2950 ** subsequent calls to other SQLite interface functions.)^
2951 **
2952 ** ^The sqlite3_errstr() interface returns the English-language text
2953 ** that describes the [result code], as UTF-8.
2954 ** ^(Memory to hold the error message string is managed internally
2955 ** and must not be freed by the application)^.
2956 **
2957 ** When the serialized [threading mode] is in use, it might be the
2958 ** case that a second error occurs on a separate thread in between
2959 ** the time of the first error and the call to these interfaces.
2960 ** When that happens, the second error will be reported since these
2961 ** interfaces always report the most recent result. To avoid
2962 ** this, each thread can obtain exclusive use of the [database connection] D
2963 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
2964 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
2965 ** all calls to the interfaces listed here are completed.
2966 **
2967 ** If an interface fails with SQLITE_MISUSE, that means the interface
2968 ** was invoked incorrectly by the application. In that case, the
2969 ** error code and message may or may not be set.
2970 */
2971 SQLITE_API int sqlite3_errcode(sqlite3 *db);
2972 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
2973 SQLITE_API const char *sqlite3_errmsg(sqlite3*);
2974 SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
2975 SQLITE_API const char *sqlite3_errstr(int);
2976
2977 /*
2978 ** CAPI3REF: SQL Statement Object
2979 ** KEYWORDS: {prepared statement} {prepared statements}
2980 **
2981 ** An instance of this object represents a single SQL statement.
2982 ** This object is variously known as a "prepared statement" or a
2983 ** "compiled SQL statement" or simply as a "statement".
2984 **
2985 ** The life of a statement object goes something like this:
2986 **
2987 ** <ol>
2988 ** <li> Create the object using [sqlite3_prepare_v2()] or a related
2989 ** function.
2990 ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
2991 ** interfaces.
2992 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
2993 ** <li> Reset the statement using [sqlite3_reset()] then go back
2994 ** to step 2. Do this zero or more times.
2995 ** <li> Destroy the object using [sqlite3_finalize()].
2996 ** </ol>
2997 **
2998 ** Refer to documentation on individual methods above for additional
2999 ** information.
3000 */
3001 typedef struct sqlite3_stmt sqlite3_stmt;
3002
3003 /*
3004 ** CAPI3REF: Run-time Limits
3005 **
3006 ** ^(This interface allows the size of various constructs to be limited
3007 ** on a connection by connection basis. The first parameter is the
3008 ** [database connection] whose limit is to be set or queried. The
3009 ** second parameter is one of the [limit categories] that define a
3010 ** class of constructs to be size limited. The third parameter is the
3011 ** new limit for that construct.)^
3012 **
3013 ** ^If the new limit is a negative number, the limit is unchanged.
3014 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3015 ** [limits | hard upper bound]
3016 ** set at compile-time by a C preprocessor macro called
3017 ** [limits | SQLITE_MAX_<i>NAME</i>].
3018 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3019 ** ^Attempts to increase a limit above its hard upper bound are
3020 ** silently truncated to the hard upper bound.
3021 **
3022 ** ^Regardless of whether or not the limit was changed, the
3023 ** [sqlite3_limit()] interface returns the prior value of the limit.
3024 ** ^Hence, to find the current value of a limit without changing it,
3025 ** simply invoke this interface with the third parameter set to -1.
3026 **
3027 ** Run-time limits are intended for use in applications that manage
3028 ** both their own internal database and also databases that are controlled
3029 ** by untrusted external sources. An example application might be a
3030 ** web browser that has its own databases for storing history and
3031 ** separate databases controlled by JavaScript applications downloaded
3032 ** off the Internet. The internal databases can be given the
3033 ** large, default limits. Databases managed by external sources can
3034 ** be given much smaller limits designed to prevent a denial of service
3035 ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
3036 ** interface to further control untrusted SQL. The size of the database
3037 ** created by an untrusted script can be contained using the
3038 ** [max_page_count] [PRAGMA].
3039 **
3040 ** New run-time limit categories may be added in future releases.
3041 */
3042 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
3043
3044 /*
3045 ** CAPI3REF: Run-Time Limit Categories
3046 ** KEYWORDS: {limit category} {*limit categories}
3047 **
3048 ** These constants define various performance limits
3049 ** that can be lowered at run-time using [sqlite3_limit()].
3050 ** The synopsis of the meanings of the various limits is shown below.
3051 ** Additional information is available at [limits | Limits in SQLite].
3052 **
3053 ** <dl>
3054 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3055 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3056 **
3057 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3058 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3059 **
3060 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3061 ** <dd>The maximum number of columns in a table definition or in the
3062 ** result set of a [SELECT] or the maximum number of columns in an index
3063 ** or in an ORDER BY or GROUP BY clause.</dd>)^
3064 **
3065 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3066 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3067 **
3068 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3069 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3070 **
3071 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3072 ** <dd>The maximum number of instructions in a virtual machine program
3073 ** used to implement an SQL statement. This limit is not currently
3074 ** enforced, though that might be added in some future release of
3075 ** SQLite.</dd>)^
3076 **
3077 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3078 ** <dd>The maximum number of arguments on a function.</dd>)^
3079 **
3080 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3081 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3082 **
3083 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3084 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3085 ** <dd>The maximum length of the pattern argument to the [LIKE] or
3086 ** [GLOB] operators.</dd>)^
3087 **
3088 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3089 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3090 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3091 **
3092 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3093 ** <dd>The maximum depth of recursion for triggers.</dd>)^
3094 ** </dl>
3095 */
3096 #define SQLITE_LIMIT_LENGTH 0
3097 #define SQLITE_LIMIT_SQL_LENGTH 1
3098 #define SQLITE_LIMIT_COLUMN 2
3099 #define SQLITE_LIMIT_EXPR_DEPTH 3
3100 #define SQLITE_LIMIT_COMPOUND_SELECT 4
3101 #define SQLITE_LIMIT_VDBE_OP 5
3102 #define SQLITE_LIMIT_FUNCTION_ARG 6
3103 #define SQLITE_LIMIT_ATTACHED 7
3104 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
3105 #define SQLITE_LIMIT_VARIABLE_NUMBER 9
3106 #define SQLITE_LIMIT_TRIGGER_DEPTH 10
3107
3108 /*
3109 ** CAPI3REF: Compiling An SQL Statement
3110 ** KEYWORDS: {SQL statement compiler}
3111 **
3112 ** To execute an SQL query, it must first be compiled into a byte-code
3113 ** program using one of these routines.
3114 **
3115 ** The first argument, "db", is a [database connection] obtained from a
3116 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3117 ** [sqlite3_open16()]. The database connection must not have been closed.
3118 **
3119 ** The second argument, "zSql", is the statement to be compiled, encoded
3120 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
3121 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
3122 ** use UTF-16.
3123 **
3124 ** ^If the nByte argument is less than zero, then zSql is read up to the
3125 ** first zero terminator. ^If nByte is non-negative, then it is the maximum
3126 ** number of bytes read from zSql. ^When nByte is non-negative, the
3127 ** zSql string ends at either the first '\000' or '\u0000' character or
3128 ** the nByte-th byte, whichever comes first. If the caller knows
3129 ** that the supplied string is nul-terminated, then there is a small
3130 ** performance advantage to be gained by passing an nByte parameter that
3131 ** is equal to the number of bytes in the input string <i>including</i>
3132 ** the nul-terminator bytes as this saves SQLite from having to
3133 ** make a copy of the input string.
3134 **
3135 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3136 ** past the end of the first SQL statement in zSql. These routines only
3137 ** compile the first statement in zSql, so *pzTail is left pointing to
3138 ** what remains uncompiled.
3139 **
3140 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3141 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
3142 ** to NULL. ^If the input text contains no SQL (if the input is an empty
3143 ** string or a comment) then *ppStmt is set to NULL.
3144 ** The calling procedure is responsible for deleting the compiled
3145 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
3146 ** ppStmt may not be NULL.
3147 **
3148 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3149 ** otherwise an [error code] is returned.
3150 **
3151 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
3152 ** recommended for all new programs. The two older interfaces are retained
3153 ** for backwards compatibility, but their use is discouraged.
3154 ** ^In the "v2" interfaces, the prepared statement
3155 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
3156 ** original SQL text. This causes the [sqlite3_step()] interface to
3157 ** behave differently in three ways:
3158 **
3159 ** <ol>
3160 ** <li>
3161 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3162 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
3163 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3164 ** retries will occur before sqlite3_step() gives up and returns an error.
3165 ** </li>
3166 **
3167 ** <li>
3168 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3169 ** [error codes] or [extended error codes]. ^The legacy behavior was that
3170 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3171 ** and the application would have to make a second call to [sqlite3_reset()]
3172 ** in order to find the underlying cause of the problem. With the "v2" prepare
3173 ** interfaces, the underlying reason for the error is returned immediately.
3174 ** </li>
3175 **
3176 ** <li>
3177 ** ^If the specific value bound to [parameter | host parameter] in the
3178 ** WHERE clause might influence the choice of query plan for a statement,
3179 ** then the statement will be automatically recompiled, as if there had been
3180 ** a schema change, on the first [sqlite3_step()] call following any change
3181 ** to the [sqlite3_bind_text | bindings] of that [parameter].
3182 ** ^The specific value of WHERE-clause [parameter] might influence the
3183 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
3184 ** or [GLOB] operator or if the parameter is compared to an indexed column
3185 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3186 ** </li>
3187 ** </ol>
3188 */
3189 SQLITE_API int sqlite3_prepare(
3190 sqlite3 *db, /* Database handle */
3191 const char *zSql, /* SQL statement, UTF-8 encoded */
3192 int nByte, /* Maximum length of zSql in bytes. */
3193 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3194 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3195 );
3196 SQLITE_API int sqlite3_prepare_v2(
3197 sqlite3 *db, /* Database handle */
3198 const char *zSql, /* SQL statement, UTF-8 encoded */
3199 int nByte, /* Maximum length of zSql in bytes. */
3200 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3201 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3202 );
3203 SQLITE_API int sqlite3_prepare16(
3204 sqlite3 *db, /* Database handle */
3205 const void *zSql, /* SQL statement, UTF-16 encoded */
3206 int nByte, /* Maximum length of zSql in bytes. */
3207 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3208 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3209 );
3210 SQLITE_API int sqlite3_prepare16_v2(
3211 sqlite3 *db, /* Database handle */
3212 const void *zSql, /* SQL statement, UTF-16 encoded */
3213 int nByte, /* Maximum length of zSql in bytes. */
3214 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3215 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3216 );
3217
3218 /*
3219 ** CAPI3REF: Retrieving Statement SQL
3220 **
3221 ** ^This interface can be used to retrieve a saved copy of the original
3222 ** SQL text used to create a [prepared statement] if that statement was
3223 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
3224 */
3225 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
3226
3227 /*
3228 ** CAPI3REF: Determine If An SQL Statement Writes The Database
3229 **
3230 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3231 ** and only if the [prepared statement] X makes no direct changes to
3232 ** the content of the database file.
3233 **
3234 ** Note that [application-defined SQL functions] or
3235 ** [virtual tables] might change the database indirectly as a side effect.
3236 ** ^(For example, if an application defines a function "eval()" that
3237 ** calls [sqlite3_exec()], then the following SQL statement would
3238 ** change the database file through side-effects:
3239 **
3240 ** <blockquote><pre>
3241 ** SELECT eval('DELETE FROM t1') FROM t2;
3242 ** </pre></blockquote>
3243 **
3244 ** But because the [SELECT] statement does not change the database file
3245 ** directly, sqlite3_stmt_readonly() would still return true.)^
3246 **
3247 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3248 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3249 ** since the statements themselves do not actually modify the database but
3250 ** rather they control the timing of when other statements modify the
3251 ** database. ^The [ATTACH] and [DETACH] statements also cause
3252 ** sqlite3_stmt_readonly() to return true since, while those statements
3253 ** change the configuration of a database connection, they do not make
3254 ** changes to the content of the database files on disk.
3255 */
3256 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3257
3258 /*
3259 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3260 **
3261 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3262 ** [prepared statement] S has been stepped at least once using
3263 ** [sqlite3_step(S)] but has not run to completion and/or has not
3264 ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
3265 ** interface returns false if S is a NULL pointer. If S is not a
3266 ** NULL pointer and is not a pointer to a valid [prepared statement]
3267 ** object, then the behavior is undefined and probably undesirable.
3268 **
3269 ** This interface can be used in combination [sqlite3_next_stmt()]
3270 ** to locate all prepared statements associated with a database
3271 ** connection that are in need of being reset. This can be used,
3272 ** for example, in diagnostic routines to search for prepared
3273 ** statements that are holding a transaction open.
3274 */
3275 SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
3276
3277 /*
3278 ** CAPI3REF: Dynamically Typed Value Object
3279 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3280 **
3281 ** SQLite uses the sqlite3_value object to represent all values
3282 ** that can be stored in a database table. SQLite uses dynamic typing
3283 ** for the values it stores. ^Values stored in sqlite3_value objects
3284 ** can be integers, floating point values, strings, BLOBs, or NULL.
3285 **
3286 ** An sqlite3_value object may be either "protected" or "unprotected".
3287 ** Some interfaces require a protected sqlite3_value. Other interfaces
3288 ** will accept either a protected or an unprotected sqlite3_value.
3289 ** Every interface that accepts sqlite3_value arguments specifies
3290 ** whether or not it requires a protected sqlite3_value.
3291 **
3292 ** The terms "protected" and "unprotected" refer to whether or not
3293 ** a mutex is held. An internal mutex is held for a protected
3294 ** sqlite3_value object but no mutex is held for an unprotected
3295 ** sqlite3_value object. If SQLite is compiled to be single-threaded
3296 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3297 ** or if SQLite is run in one of reduced mutex modes
3298 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3299 ** then there is no distinction between protected and unprotected
3300 ** sqlite3_value objects and they can be used interchangeably. However,
3301 ** for maximum code portability it is recommended that applications
3302 ** still make the distinction between protected and unprotected
3303 ** sqlite3_value objects even when not strictly required.
3304 **
3305 ** ^The sqlite3_value objects that are passed as parameters into the
3306 ** implementation of [application-defined SQL functions] are protected.
3307 ** ^The sqlite3_value object returned by
3308 ** [sqlite3_column_value()] is unprotected.
3309 ** Unprotected sqlite3_value objects may only be used with
3310 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
3311 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
3312 ** interfaces require protected sqlite3_value objects.
3313 */
3314 typedef struct Mem sqlite3_value;
3315
3316 /*
3317 ** CAPI3REF: SQL Function Context Object
3318 **
3319 ** The context in which an SQL function executes is stored in an
3320 ** sqlite3_context object. ^A pointer to an sqlite3_context object
3321 ** is always first parameter to [application-defined SQL functions].
3322 ** The application-defined SQL function implementation will pass this
3323 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3324 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3325 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3326 ** and/or [sqlite3_set_auxdata()].
3327 */
3328 typedef struct sqlite3_context sqlite3_context;
3329
3330 /*
3331 ** CAPI3REF: Binding Values To Prepared Statements
3332 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3333 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3334 **
3335 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3336 ** literals may be replaced by a [parameter] that matches one of following
3337 ** templates:
3338 **
3339 ** <ul>
3340 ** <li> ?
3341 ** <li> ?NNN
3342 ** <li> :VVV
3343 ** <li> @VVV
3344 ** <li> $VVV
3345 ** </ul>
3346 **
3347 ** In the templates above, NNN represents an integer literal,
3348 ** and VVV represents an alphanumeric identifier.)^ ^The values of these
3349 ** parameters (also called "host parameter names" or "SQL parameters")
3350 ** can be set using the sqlite3_bind_*() routines defined here.
3351 **
3352 ** ^The first argument to the sqlite3_bind_*() routines is always
3353 ** a pointer to the [sqlite3_stmt] object returned from
3354 ** [sqlite3_prepare_v2()] or its variants.
3355 **
3356 ** ^The second argument is the index of the SQL parameter to be set.
3357 ** ^The leftmost SQL parameter has an index of 1. ^When the same named
3358 ** SQL parameter is used more than once, second and subsequent
3359 ** occurrences have the same index as the first occurrence.
3360 ** ^The index for named parameters can be looked up using the
3361 ** [sqlite3_bind_parameter_index()] API if desired. ^The index
3362 ** for "?NNN" parameters is the value of NNN.
3363 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
3364 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3365 **
3366 ** ^The third argument is the value to bind to the parameter.
3367 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3368 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3369 ** is ignored and the end result is the same as sqlite3_bind_null().
3370 **
3371 ** ^(In those routines that have a fourth argument, its value is the
3372 ** number of bytes in the parameter. To be clear: the value is the
3373 ** number of <u>bytes</u> in the value, not the number of characters.)^
3374 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3375 ** is negative, then the length of the string is
3376 ** the number of bytes up to the first zero terminator.
3377 ** If the fourth parameter to sqlite3_bind_blob() is negative, then
3378 ** the behavior is undefined.
3379 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3380 ** or sqlite3_bind_text16() then that parameter must be the byte offset
3381 ** where the NUL terminator would occur assuming the string were NUL
3382 ** terminated. If any NUL characters occur at byte offsets less than
3383 ** the value of the fourth parameter then the resulting string value will
3384 ** contain embedded NULs. The result of expressions involving strings
3385 ** with embedded NULs is undefined.
3386 **
3387 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
3388 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
3389 ** string after SQLite has finished with it. ^The destructor is called
3390 ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(),
3391 ** sqlite3_bind_text(), or sqlite3_bind_text16() fails.
3392 ** ^If the fifth argument is
3393 ** the special value [SQLITE_STATIC], then SQLite assumes that the
3394 ** information is in static, unmanaged space and does not need to be freed.
3395 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3396 ** SQLite makes its own private copy of the data immediately, before
3397 ** the sqlite3_bind_*() routine returns.
3398 **
3399 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3400 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
3401 ** (just an integer to hold its size) while it is being processed.
3402 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
3403 ** content is later written using
3404 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
3405 ** ^A negative value for the zeroblob results in a zero-length BLOB.
3406 **
3407 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3408 ** for the [prepared statement] or with a prepared statement for which
3409 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3410 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
3411 ** routine is passed a [prepared statement] that has been finalized, the
3412 ** result is undefined and probably harmful.
3413 **
3414 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3415 ** ^Unbound parameters are interpreted as NULL.
3416 **
3417 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3418 ** [error code] if anything goes wrong.
3419 ** ^[SQLITE_RANGE] is returned if the parameter
3420 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
3421 **
3422 ** See also: [sqlite3_bind_parameter_count()],
3423 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3424 */
3425 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3426 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
3427 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
3428 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3429 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
3430 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
3431 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3432 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3433 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3434
3435 /*
3436 ** CAPI3REF: Number Of SQL Parameters
3437 **
3438 ** ^This routine can be used to find the number of [SQL parameters]
3439 ** in a [prepared statement]. SQL parameters are tokens of the
3440 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3441 ** placeholders for values that are [sqlite3_bind_blob | bound]
3442 ** to the parameters at a later time.
3443 **
3444 ** ^(This routine actually returns the index of the largest (rightmost)
3445 ** parameter. For all forms except ?NNN, this will correspond to the
3446 ** number of unique parameters. If parameters of the ?NNN form are used,
3447 ** there may be gaps in the list.)^
3448 **
3449 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3450 ** [sqlite3_bind_parameter_name()], and
3451 ** [sqlite3_bind_parameter_index()].
3452 */
3453 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
3454
3455 /*
3456 ** CAPI3REF: Name Of A Host Parameter
3457 **
3458 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
3459 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
3460 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3461 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3462 ** respectively.
3463 ** In other words, the initial ":" or "$" or "@" or "?"
3464 ** is included as part of the name.)^
3465 ** ^Parameters of the form "?" without a following integer have no name
3466 ** and are referred to as "nameless" or "anonymous parameters".
3467 **
3468 ** ^The first host parameter has an index of 1, not 0.
3469 **
3470 ** ^If the value N is out of range or if the N-th parameter is
3471 ** nameless, then NULL is returned. ^The returned string is
3472 ** always in UTF-8 encoding even if the named parameter was
3473 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
3474 ** [sqlite3_prepare16_v2()].
3475 **
3476 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3477 ** [sqlite3_bind_parameter_count()], and
3478 ** [sqlite3_bind_parameter_index()].
3479 */
3480 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
3481
3482 /*
3483 ** CAPI3REF: Index Of A Parameter With A Given Name
3484 **
3485 ** ^Return the index of an SQL parameter given its name. ^The
3486 ** index value returned is suitable for use as the second
3487 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
3488 ** is returned if no matching parameter is found. ^The parameter
3489 ** name must be given in UTF-8 even if the original statement
3490 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3491 **
3492 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3493 ** [sqlite3_bind_parameter_count()], and
3494 ** [sqlite3_bind_parameter_index()].
3495 */
3496 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
3497
3498 /*
3499 ** CAPI3REF: Reset All Bindings On A Prepared Statement
3500 **
3501 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3502 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3503 ** ^Use this routine to reset all host parameters to NULL.
3504 */
3505 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
3506
3507 /*
3508 ** CAPI3REF: Number Of Columns In A Result Set
3509 **
3510 ** ^Return the number of columns in the result set returned by the
3511 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3512 ** statement that does not return data (for example an [UPDATE]).
3513 **
3514 ** See also: [sqlite3_data_count()]
3515 */
3516 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
3517
3518 /*
3519 ** CAPI3REF: Column Names In A Result Set
3520 **
3521 ** ^These routines return the name assigned to a particular column
3522 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
3523 ** interface returns a pointer to a zero-terminated UTF-8 string
3524 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
3525 ** UTF-16 string. ^The first parameter is the [prepared statement]
3526 ** that implements the [SELECT] statement. ^The second parameter is the
3527 ** column number. ^The leftmost column is number 0.
3528 **
3529 ** ^The returned string pointer is valid until either the [prepared statement]
3530 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3531 ** reprepared by the first call to [sqlite3_step()] for a particular run
3532 ** or until the next call to
3533 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3534 **
3535 ** ^If sqlite3_malloc() fails during the processing of either routine
3536 ** (for example during a conversion from UTF-8 to UTF-16) then a
3537 ** NULL pointer is returned.
3538 **
3539 ** ^The name of a result column is the value of the "AS" clause for
3540 ** that column, if there is an AS clause. If there is no AS clause
3541 ** then the name of the column is unspecified and may change from
3542 ** one release of SQLite to the next.
3543 */
3544 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
3545 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
3546
3547 /*
3548 ** CAPI3REF: Source Of Data In A Query Result
3549 **
3550 ** ^These routines provide a means to determine the database, table, and
3551 ** table column that is the origin of a particular result column in
3552 ** [SELECT] statement.
3553 ** ^The name of the database or table or column can be returned as
3554 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
3555 ** the database name, the _table_ routines return the table name, and
3556 ** the origin_ routines return the column name.
3557 ** ^The returned string is valid until the [prepared statement] is destroyed
3558 ** using [sqlite3_finalize()] or until the statement is automatically
3559 ** reprepared by the first call to [sqlite3_step()] for a particular run
3560 ** or until the same information is requested
3561 ** again in a different encoding.
3562 **
3563 ** ^The names returned are the original un-aliased names of the
3564 ** database, table, and column.
3565 **
3566 ** ^The first argument to these interfaces is a [prepared statement].
3567 ** ^These functions return information about the Nth result column returned by
3568 ** the statement, where N is the second function argument.
3569 ** ^The left-most column is column 0 for these routines.
3570 **
3571 ** ^If the Nth column returned by the statement is an expression or
3572 ** subquery and is not a column value, then all of these functions return
3573 ** NULL. ^These routine might also return NULL if a memory allocation error
3574 ** occurs. ^Otherwise, they return the name of the attached database, table,
3575 ** or column that query result column was extracted from.
3576 **
3577 ** ^As with all other SQLite APIs, those whose names end with "16" return
3578 ** UTF-16 encoded strings and the other functions return UTF-8.
3579 **
3580 ** ^These APIs are only available if the library was compiled with the
3581 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3582 **
3583 ** If two or more threads call one or more of these routines against the same
3584 ** prepared statement and column at the same time then the results are
3585 ** undefined.
3586 **
3587 ** If two or more threads call one or more
3588 ** [sqlite3_column_database_name | column metadata interfaces]
3589 ** for the same [prepared statement] and result column
3590 ** at the same time then the results are undefined.
3591 */
3592 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
3593 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
3594 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
3595 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
3596 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
3597 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
3598
3599 /*
3600 ** CAPI3REF: Declared Datatype Of A Query Result
3601 **
3602 ** ^(The first parameter is a [prepared statement].
3603 ** If this statement is a [SELECT] statement and the Nth column of the
3604 ** returned result set of that [SELECT] is a table column (not an
3605 ** expression or subquery) then the declared type of the table
3606 ** column is returned.)^ ^If the Nth column of the result set is an
3607 ** expression or subquery, then a NULL pointer is returned.
3608 ** ^The returned string is always UTF-8 encoded.
3609 **
3610 ** ^(For example, given the database schema:
3611 **
3612 ** CREATE TABLE t1(c1 VARIANT);
3613 **
3614 ** and the following statement to be compiled:
3615 **
3616 ** SELECT c1 + 1, c1 FROM t1;
3617 **
3618 ** this routine would return the string "VARIANT" for the second result
3619 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
3620 **
3621 ** ^SQLite uses dynamic run-time typing. ^So just because a column
3622 ** is declared to contain a particular type does not mean that the
3623 ** data stored in that column is of the declared type. SQLite is
3624 ** strongly typed, but the typing is dynamic not static. ^Type
3625 ** is associated with individual values, not with the containers
3626 ** used to hold those values.
3627 */
3628 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
3629 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
3630
3631 /*
3632 ** CAPI3REF: Evaluate An SQL Statement
3633 **
3634 ** After a [prepared statement] has been prepared using either
3635 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3636 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3637 ** must be called one or more times to evaluate the statement.
3638 **
3639 ** The details of the behavior of the sqlite3_step() interface depend
3640 ** on whether the statement was prepared using the newer "v2" interface
3641 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3642 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
3643 ** new "v2" interface is recommended for new applications but the legacy
3644 ** interface will continue to be supported.
3645 **
3646 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3647 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3648 ** ^With the "v2" interface, any of the other [result codes] or
3649 ** [extended result codes] might be returned as well.
3650 **
3651 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3652 ** database locks it needs to do its job. ^If the statement is a [COMMIT]
3653 ** or occurs outside of an explicit transaction, then you can retry the
3654 ** statement. If the statement is not a [COMMIT] and occurs within an
3655 ** explicit transaction then you should rollback the transaction before
3656 ** continuing.
3657 **
3658 ** ^[SQLITE_DONE] means that the statement has finished executing
3659 ** successfully. sqlite3_step() should not be called again on this virtual
3660 ** machine without first calling [sqlite3_reset()] to reset the virtual
3661 ** machine back to its initial state.
3662 **
3663 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3664 ** is returned each time a new row of data is ready for processing by the
3665 ** caller. The values may be accessed using the [column access functions].
3666 ** sqlite3_step() is called again to retrieve the next row of data.
3667 **
3668 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3669 ** violation) has occurred. sqlite3_step() should not be called again on
3670 ** the VM. More information may be found by calling [sqlite3_errmsg()].
3671 ** ^With the legacy interface, a more specific error code (for example,
3672 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3673 ** can be obtained by calling [sqlite3_reset()] on the
3674 ** [prepared statement]. ^In the "v2" interface,
3675 ** the more specific error code is returned directly by sqlite3_step().
3676 **
3677 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3678 ** Perhaps it was called on a [prepared statement] that has
3679 ** already been [sqlite3_finalize | finalized] or on one that had
3680 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
3681 ** be the case that the same database connection is being used by two or
3682 ** more threads at the same moment in time.
3683 **
3684 ** For all versions of SQLite up to and including 3.6.23.1, a call to
3685 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
3686 ** other than [SQLITE_ROW] before any subsequent invocation of
3687 ** sqlite3_step(). Failure to reset the prepared statement using
3688 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3689 ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began
3690 ** calling [sqlite3_reset()] automatically in this circumstance rather
3691 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
3692 ** break because any application that ever receives an SQLITE_MISUSE error
3693 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
3694 ** can be used to restore the legacy behavior.
3695 **
3696 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3697 ** API always returns a generic error code, [SQLITE_ERROR], following any
3698 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
3699 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3700 ** specific [error codes] that better describes the error.
3701 ** We admit that this is a goofy design. The problem has been fixed
3702 ** with the "v2" interface. If you prepare all of your SQL statements
3703 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3704 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3705 ** then the more specific [error codes] are returned directly
3706 ** by sqlite3_step(). The use of the "v2" interface is recommended.
3707 */
3708 SQLITE_API int sqlite3_step(sqlite3_stmt*);
3709
3710 /*
3711 ** CAPI3REF: Number of columns in a result set
3712 **
3713 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
3714 ** current row of the result set of [prepared statement] P.
3715 ** ^If prepared statement P does not have results ready to return
3716 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3717 ** interfaces) then sqlite3_data_count(P) returns 0.
3718 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3719 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
3720 ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
3721 ** will return non-zero if previous call to [sqlite3_step](P) returned
3722 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
3723 ** where it always returns zero since each step of that multi-step
3724 ** pragma returns 0 columns of data.
3725 **
3726 ** See also: [sqlite3_column_count()]
3727 */
3728 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
3729
3730 /*
3731 ** CAPI3REF: Fundamental Datatypes
3732 ** KEYWORDS: SQLITE_TEXT
3733 **
3734 ** ^(Every value in SQLite has one of five fundamental datatypes:
3735 **
3736 ** <ul>
3737 ** <li> 64-bit signed integer
3738 ** <li> 64-bit IEEE floating point number
3739 ** <li> string
3740 ** <li> BLOB
3741 ** <li> NULL
3742 ** </ul>)^
3743 **
3744 ** These constants are codes for each of those types.
3745 **
3746 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3747 ** for a completely different meaning. Software that links against both
3748 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3749 ** SQLITE_TEXT.
3750 */
3751 #define SQLITE_INTEGER 1
3752 #define SQLITE_FLOAT 2
3753 #define SQLITE_BLOB 4
3754 #define SQLITE_NULL 5
3755 #ifdef SQLITE_TEXT
3756 # undef SQLITE_TEXT
3757 #else
3758 # define SQLITE_TEXT 3
3759 #endif
3760 #define SQLITE3_TEXT 3
3761
3762 /*
3763 ** CAPI3REF: Result Values From A Query
3764 ** KEYWORDS: {column access functions}
3765 **
3766 ** These routines form the "result set" interface.
3767 **
3768 ** ^These routines return information about a single column of the current
3769 ** result row of a query. ^In every case the first argument is a pointer
3770 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3771 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3772 ** and the second argument is the index of the column for which information
3773 ** should be returned. ^The leftmost column of the result set has the index 0.
3774 ** ^The number of columns in the result can be determined using
3775 ** [sqlite3_column_count()].
3776 **
3777 ** If the SQL statement does not currently point to a valid row, or if the
3778 ** column index is out of range, the result is undefined.
3779 ** These routines may only be called when the most recent call to
3780 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3781 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3782 ** If any of these routines are called after [sqlite3_reset()] or
3783 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3784 ** something other than [SQLITE_ROW], the results are undefined.
3785 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3786 ** are called from a different thread while any of these routines
3787 ** are pending, then the results are undefined.
3788 **
3789 ** ^The sqlite3_column_type() routine returns the
3790 ** [SQLITE_INTEGER | datatype code] for the initial data type
3791 ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
3792 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
3793 ** returned by sqlite3_column_type() is only meaningful if no type
3794 ** conversions have occurred as described below. After a type conversion,
3795 ** the value returned by sqlite3_column_type() is undefined. Future
3796 ** versions of SQLite may change the behavior of sqlite3_column_type()
3797 ** following a type conversion.
3798 **
3799 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3800 ** routine returns the number of bytes in that BLOB or string.
3801 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3802 ** the string to UTF-8 and then returns the number of bytes.
3803 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
3804 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3805 ** the number of bytes in that string.
3806 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3807 **
3808 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3809 ** routine returns the number of bytes in that BLOB or string.
3810 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3811 ** the string to UTF-16 and then returns the number of bytes.
3812 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3813 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3814 ** the number of bytes in that string.
3815 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3816 **
3817 ** ^The values returned by [sqlite3_column_bytes()] and
3818 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3819 ** of the string. ^For clarity: the values returned by
3820 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3821 ** bytes in the string, not the number of characters.
3822 **
3823 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3824 ** even empty strings, are always zero-terminated. ^The return
3825 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3826 **
3827 ** ^The object returned by [sqlite3_column_value()] is an
3828 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object
3829 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
3830 ** If the [unprotected sqlite3_value] object returned by
3831 ** [sqlite3_column_value()] is used in any other way, including calls
3832 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3833 ** or [sqlite3_value_bytes()], then the behavior is undefined.
3834 **
3835 ** These routines attempt to convert the value where appropriate. ^For
3836 ** example, if the internal representation is FLOAT and a text result
3837 ** is requested, [sqlite3_snprintf()] is used internally to perform the
3838 ** conversion automatically. ^(The following table details the conversions
3839 ** that are applied:
3840 **
3841 ** <blockquote>
3842 ** <table border="1">
3843 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
3844 **
3845 ** <tr><td> NULL <td> INTEGER <td> Result is 0
3846 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
3847 ** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer
3848 ** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer
3849 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
3850 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
3851 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
3852 ** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER
3853 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
3854 ** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB
3855 ** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER
3856 ** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL
3857 ** <tr><td> TEXT <td> BLOB <td> No change
3858 ** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER
3859 ** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL
3860 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
3861 ** </table>
3862 ** </blockquote>)^
3863 **
3864 ** The table above makes reference to standard C library functions atoi()
3865 ** and atof(). SQLite does not really use these functions. It has its
3866 ** own equivalent internal routines. The atoi() and atof() names are
3867 ** used in the table for brevity and because they are familiar to most
3868 ** C programmers.
3869 **
3870 ** Note that when type conversions occur, pointers returned by prior
3871 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
3872 ** sqlite3_column_text16() may be invalidated.
3873 ** Type conversions and pointer invalidations might occur
3874 ** in the following cases:
3875 **
3876 ** <ul>
3877 ** <li> The initial content is a BLOB and sqlite3_column_text() or
3878 ** sqlite3_column_text16() is called. A zero-terminator might
3879 ** need to be added to the string.</li>
3880 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
3881 ** sqlite3_column_text16() is called. The content must be converted
3882 ** to UTF-16.</li>
3883 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
3884 ** sqlite3_column_text() is called. The content must be converted
3885 ** to UTF-8.</li>
3886 ** </ul>
3887 **
3888 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
3889 ** not invalidate a prior pointer, though of course the content of the buffer
3890 ** that the prior pointer references will have been modified. Other kinds
3891 ** of conversion are done in place when it is possible, but sometimes they
3892 ** are not possible and in those cases prior pointers are invalidated.
3893 **
3894 ** The safest and easiest to remember policy is to invoke these routines
3895 ** in one of the following ways:
3896 **
3897 ** <ul>
3898 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
3899 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
3900 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
3901 ** </ul>
3902 **
3903 ** In other words, you should call sqlite3_column_text(),
3904 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
3905 ** into the desired format, then invoke sqlite3_column_bytes() or
3906 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
3907 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
3908 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
3909 ** with calls to sqlite3_column_bytes().
3910 **
3911 ** ^The pointers returned are valid until a type conversion occurs as
3912 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
3913 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
3914 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned
3915 ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
3916 ** [sqlite3_free()].
3917 **
3918 ** ^(If a memory allocation error occurs during the evaluation of any
3919 ** of these routines, a default value is returned. The default value
3920 ** is either the integer 0, the floating point number 0.0, or a NULL
3921 ** pointer. Subsequent calls to [sqlite3_errcode()] will return
3922 ** [SQLITE_NOMEM].)^
3923 */
3924 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
3925 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
3926 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
3927 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
3928 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
3929 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
3930 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
3931 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
3932 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
3933 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
3934
3935 /*
3936 ** CAPI3REF: Destroy A Prepared Statement Object
3937 **
3938 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
3939 ** ^If the most recent evaluation of the statement encountered no errors
3940 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
3941 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
3942 ** sqlite3_finalize(S) returns the appropriate [error code] or
3943 ** [extended error code].
3944 **
3945 ** ^The sqlite3_finalize(S) routine can be called at any point during
3946 ** the life cycle of [prepared statement] S:
3947 ** before statement S is ever evaluated, after
3948 ** one or more calls to [sqlite3_reset()], or after any call
3949 ** to [sqlite3_step()] regardless of whether or not the statement has
3950 ** completed execution.
3951 **
3952 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
3953 **
3954 ** The application must finalize every [prepared statement] in order to avoid
3955 ** resource leaks. It is a grievous error for the application to try to use
3956 ** a prepared statement after it has been finalized. Any use of a prepared
3957 ** statement after it has been finalized can result in undefined and
3958 ** undesirable behavior such as segfaults and heap corruption.
3959 */
3960 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
3961
3962 /*
3963 ** CAPI3REF: Reset A Prepared Statement Object
3964 **
3965 ** The sqlite3_reset() function is called to reset a [prepared statement]
3966 ** object back to its initial state, ready to be re-executed.
3967 ** ^Any SQL statement variables that had values bound to them using
3968 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
3969 ** Use [sqlite3_clear_bindings()] to reset the bindings.
3970 **
3971 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
3972 ** back to the beginning of its program.
3973 **
3974 ** ^If the most recent call to [sqlite3_step(S)] for the
3975 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
3976 ** or if [sqlite3_step(S)] has never before been called on S,
3977 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
3978 **
3979 ** ^If the most recent call to [sqlite3_step(S)] for the
3980 ** [prepared statement] S indicated an error, then
3981 ** [sqlite3_reset(S)] returns an appropriate [error code].
3982 **
3983 ** ^The [sqlite3_reset(S)] interface does not change the values
3984 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
3985 */
3986 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
3987
3988 /*
3989 ** CAPI3REF: Create Or Redefine SQL Functions
3990 ** KEYWORDS: {function creation routines}
3991 ** KEYWORDS: {application-defined SQL function}
3992 ** KEYWORDS: {application-defined SQL functions}
3993 **
3994 ** ^These functions (collectively known as "function creation routines")
3995 ** are used to add SQL functions or aggregates or to redefine the behavior
3996 ** of existing SQL functions or aggregates. The only differences between
3997 ** these routines are the text encoding expected for
3998 ** the second parameter (the name of the function being created)
3999 ** and the presence or absence of a destructor callback for
4000 ** the application data pointer.
4001 **
4002 ** ^The first parameter is the [database connection] to which the SQL
4003 ** function is to be added. ^If an application uses more than one database
4004 ** connection then application-defined SQL functions must be added
4005 ** to each database connection separately.
4006 **
4007 ** ^The second parameter is the name of the SQL function to be created or
4008 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
4009 ** representation, exclusive of the zero-terminator. ^Note that the name
4010 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4011 ** ^Any attempt to create a function with a longer name
4012 ** will result in [SQLITE_MISUSE] being returned.
4013 **
4014 ** ^The third parameter (nArg)
4015 ** is the number of arguments that the SQL function or
4016 ** aggregate takes. ^If this parameter is -1, then the SQL function or
4017 ** aggregate may take any number of arguments between 0 and the limit
4018 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
4019 ** parameter is less than -1 or greater than 127 then the behavior is
4020 ** undefined.
4021 **
4022 ** ^The fourth parameter, eTextRep, specifies what
4023 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4024 ** its parameters. The application should set this parameter to
4025 ** [SQLITE_UTF16LE] if the function implementation invokes
4026 ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4027 ** implementation invokes [sqlite3_value_text16be()] on an input, or
4028 ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4029 ** otherwise. ^The same SQL function may be registered multiple times using
4030 ** different preferred text encodings, with different implementations for
4031 ** each encoding.
4032 ** ^When multiple implementations of the same function are available, SQLite
4033 ** will pick the one that involves the least amount of data conversion.
4034 **
4035 ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4036 ** to signal that the function will always return the same result given
4037 ** the same inputs within a single SQL statement. Most SQL functions are
4038 ** deterministic. The built-in [random()] SQL function is an example of a
4039 ** function that is not deterministic. The SQLite query planner is able to
4040 ** perform additional optimizations on deterministic functions, so use
4041 ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4042 **
4043 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
4044 ** function can gain access to this pointer using [sqlite3_user_data()].)^
4045 **
4046 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
4047 ** pointers to C-language functions that implement the SQL function or
4048 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4049 ** callback only; NULL pointers must be passed as the xStep and xFinal
4050 ** parameters. ^An aggregate SQL function requires an implementation of xStep
4051 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4052 ** SQL function or aggregate, pass NULL pointers for all three function
4053 ** callbacks.
4054 **
4055 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
4056 ** then it is destructor for the application data pointer.
4057 ** The destructor is invoked when the function is deleted, either by being
4058 ** overloaded or when the database connection closes.)^
4059 ** ^The destructor is also invoked if the call to
4060 ** sqlite3_create_function_v2() fails.
4061 ** ^When the destructor callback of the tenth parameter is invoked, it
4062 ** is passed a single argument which is a copy of the application data
4063 ** pointer which was the fifth parameter to sqlite3_create_function_v2().
4064 **
4065 ** ^It is permitted to register multiple implementations of the same
4066 ** functions with the same name but with either differing numbers of
4067 ** arguments or differing preferred text encodings. ^SQLite will use
4068 ** the implementation that most closely matches the way in which the
4069 ** SQL function is used. ^A function implementation with a non-negative
4070 ** nArg parameter is a better match than a function implementation with
4071 ** a negative nArg. ^A function where the preferred text encoding
4072 ** matches the database encoding is a better
4073 ** match than a function where the encoding is different.
4074 ** ^A function where the encoding difference is between UTF16le and UTF16be
4075 ** is a closer match than a function where the encoding difference is
4076 ** between UTF8 and UTF16.
4077 **
4078 ** ^Built-in functions may be overloaded by new application-defined functions.
4079 **
4080 ** ^An application-defined function is permitted to call other
4081 ** SQLite interfaces. However, such calls must not
4082 ** close the database connection nor finalize or reset the prepared
4083 ** statement in which the function is running.
4084 */
4085 SQLITE_API int sqlite3_create_function(
4086 sqlite3 *db,
4087 const char *zFunctionName,
4088 int nArg,
4089 int eTextRep,
4090 void *pApp,
4091 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4092 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4093 void (*xFinal)(sqlite3_context*)
4094 );
4095 SQLITE_API int sqlite3_create_function16(
4096 sqlite3 *db,
4097 const void *zFunctionName,
4098 int nArg,
4099 int eTextRep,
4100 void *pApp,
4101 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4102 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4103 void (*xFinal)(sqlite3_context*)
4104 );
4105 SQLITE_API int sqlite3_create_function_v2(
4106 sqlite3 *db,
4107 const char *zFunctionName,
4108 int nArg,
4109 int eTextRep,
4110 void *pApp,
4111 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4112 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4113 void (*xFinal)(sqlite3_context*),
4114 void(*xDestroy)(void*)
4115 );
4116
4117 /*
4118 ** CAPI3REF: Text Encodings
4119 **
4120 ** These constant define integer codes that represent the various
4121 ** text encodings supported by SQLite.
4122 */
4123 #define SQLITE_UTF8 1
4124 #define SQLITE_UTF16LE 2
4125 #define SQLITE_UTF16BE 3
4126 #define SQLITE_UTF16 4 /* Use native byte order */
4127 #define SQLITE_ANY 5 /* Deprecated */
4128 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
4129
4130 /*
4131 ** CAPI3REF: Function Flags
4132 **
4133 ** These constants may be ORed together with the
4134 ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4135 ** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4136 ** [sqlite3_create_function_v2()].
4137 */
4138 #define SQLITE_DETERMINISTIC 0x800
4139
4140 /*
4141 ** CAPI3REF: Deprecated Functions
4142 ** DEPRECATED
4143 **
4144 ** These functions are [deprecated]. In order to maintain
4145 ** backwards compatibility with older code, these functions continue
4146 ** to be supported. However, new applications should avoid
4147 ** the use of these functions. To help encourage people to avoid
4148 ** using these functions, we are not going to tell you what they do.
4149 */
4150 #ifndef SQLITE_OMIT_DEPRECATED
4151 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
4152 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
4153 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4154 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
4155 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
4156 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4157 void*,sqlite3_int64);
4158 #endif
4159
4160 /*
4161 ** CAPI3REF: Obtaining SQL Function Parameter Values
4162 **
4163 ** The C-language implementation of SQL functions and aggregates uses
4164 ** this set of interface routines to access the parameter values on
4165 ** the function or aggregate.
4166 **
4167 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
4168 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
4169 ** define callbacks that implement the SQL functions and aggregates.
4170 ** The 3rd parameter to these callbacks is an array of pointers to
4171 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
4172 ** each parameter to the SQL function. These routines are used to
4173 ** extract values from the [sqlite3_value] objects.
4174 **
4175 ** These routines work only with [protected sqlite3_value] objects.
4176 ** Any attempt to use these routines on an [unprotected sqlite3_value]
4177 ** object results in undefined behavior.
4178 **
4179 ** ^These routines work just like the corresponding [column access functions]
4180 ** except that these routines take a single [protected sqlite3_value] object
4181 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4182 **
4183 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4184 ** in the native byte-order of the host machine. ^The
4185 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4186 ** extract UTF-16 strings as big-endian and little-endian respectively.
4187 **
4188 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
4189 ** numeric affinity to the value. This means that an attempt is
4190 ** made to convert the value to an integer or floating point. If
4191 ** such a conversion is possible without loss of information (in other
4192 ** words, if the value is a string that looks like a number)
4193 ** then the conversion is performed. Otherwise no conversion occurs.
4194 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4195 **
4196 ** Please pay particular attention to the fact that the pointer returned
4197 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4198 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4199 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4200 ** or [sqlite3_value_text16()].
4201 **
4202 ** These routines must be called from the same thread as
4203 ** the SQL function that supplied the [sqlite3_value*] parameters.
4204 */
4205 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
4206 SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
4207 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
4208 SQLITE_API double sqlite3_value_double(sqlite3_value*);
4209 SQLITE_API int sqlite3_value_int(sqlite3_value*);
4210 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
4211 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
4212 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
4213 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
4214 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
4215 SQLITE_API int sqlite3_value_type(sqlite3_value*);
4216 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
4217
4218 /*
4219 ** CAPI3REF: Obtain Aggregate Function Context
4220 **
4221 ** Implementations of aggregate SQL functions use this
4222 ** routine to allocate memory for storing their state.
4223 **
4224 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4225 ** for a particular aggregate function, SQLite
4226 ** allocates N of memory, zeroes out that memory, and returns a pointer
4227 ** to the new memory. ^On second and subsequent calls to
4228 ** sqlite3_aggregate_context() for the same aggregate function instance,
4229 ** the same buffer is returned. Sqlite3_aggregate_context() is normally
4230 ** called once for each invocation of the xStep callback and then one
4231 ** last time when the xFinal callback is invoked. ^(When no rows match
4232 ** an aggregate query, the xStep() callback of the aggregate function
4233 ** implementation is never called and xFinal() is called exactly once.
4234 ** In those cases, sqlite3_aggregate_context() might be called for the
4235 ** first time from within xFinal().)^
4236 **
4237 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
4238 ** when first called if N is less than or equal to zero or if a memory
4239 ** allocate error occurs.
4240 **
4241 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4242 ** determined by the N parameter on first successful call. Changing the
4243 ** value of N in subsequent call to sqlite3_aggregate_context() within
4244 ** the same aggregate function instance will not resize the memory
4245 ** allocation.)^ Within the xFinal callback, it is customary to set
4246 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
4247 ** pointless memory allocations occur.
4248 **
4249 ** ^SQLite automatically frees the memory allocated by
4250 ** sqlite3_aggregate_context() when the aggregate query concludes.
4251 **
4252 ** The first parameter must be a copy of the
4253 ** [sqlite3_context | SQL function context] that is the first parameter
4254 ** to the xStep or xFinal callback routine that implements the aggregate
4255 ** function.
4256 **
4257 ** This routine must be called from the same thread in which
4258 ** the aggregate SQL function is running.
4259 */
4260 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4261
4262 /*
4263 ** CAPI3REF: User Data For Functions
4264 **
4265 ** ^The sqlite3_user_data() interface returns a copy of
4266 ** the pointer that was the pUserData parameter (the 5th parameter)
4267 ** of the [sqlite3_create_function()]
4268 ** and [sqlite3_create_function16()] routines that originally
4269 ** registered the application defined function.
4270 **
4271 ** This routine must be called from the same thread in which
4272 ** the application-defined function is running.
4273 */
4274 SQLITE_API void *sqlite3_user_data(sqlite3_context*);
4275
4276 /*
4277 ** CAPI3REF: Database Connection For Functions
4278 **
4279 ** ^The sqlite3_context_db_handle() interface returns a copy of
4280 ** the pointer to the [database connection] (the 1st parameter)
4281 ** of the [sqlite3_create_function()]
4282 ** and [sqlite3_create_function16()] routines that originally
4283 ** registered the application defined function.
4284 */
4285 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
4286
4287 /*
4288 ** CAPI3REF: Function Auxiliary Data
4289 **
4290 ** These functions may be used by (non-aggregate) SQL functions to
4291 ** associate metadata with argument values. If the same value is passed to
4292 ** multiple invocations of the same SQL function during query execution, under
4293 ** some circumstances the associated metadata may be preserved. An example
4294 ** of where this might be useful is in a regular-expression matching
4295 ** function. The compiled version of the regular expression can be stored as
4296 ** metadata associated with the pattern string.
4297 ** Then as long as the pattern string remains the same,
4298 ** the compiled regular expression can be reused on multiple
4299 ** invocations of the same function.
4300 **
4301 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
4302 ** associated by the sqlite3_set_auxdata() function with the Nth argument
4303 ** value to the application-defined function. ^If there is no metadata
4304 ** associated with the function argument, this sqlite3_get_auxdata() interface
4305 ** returns a NULL pointer.
4306 **
4307 ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
4308 ** argument of the application-defined function. ^Subsequent
4309 ** calls to sqlite3_get_auxdata(C,N) return P from the most recent
4310 ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
4311 ** NULL if the metadata has been discarded.
4312 ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
4313 ** SQLite will invoke the destructor function X with parameter P exactly
4314 ** once, when the metadata is discarded.
4315 ** SQLite is free to discard the metadata at any time, including: <ul>
4316 ** <li> when the corresponding function parameter changes, or
4317 ** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
4318 ** SQL statement, or
4319 ** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or
4320 ** <li> during the original sqlite3_set_auxdata() call when a memory
4321 ** allocation error occurs. </ul>)^
4322 **
4323 ** Note the last bullet in particular. The destructor X in
4324 ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
4325 ** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
4326 ** should be called near the end of the function implementation and the
4327 ** function implementation should not make any use of P after
4328 ** sqlite3_set_auxdata() has been called.
4329 **
4330 ** ^(In practice, metadata is preserved between function calls for
4331 ** function parameters that are compile-time constants, including literal
4332 ** values and [parameters] and expressions composed from the same.)^
4333 **
4334 ** These routines must be called from the same thread in which
4335 ** the SQL function is running.
4336 */
4337 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
4338 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
4339
4340
4341 /*
4342 ** CAPI3REF: Constants Defining Special Destructor Behavior
4343 **
4344 ** These are special values for the destructor that is passed in as the
4345 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
4346 ** argument is SQLITE_STATIC, it means that the content pointer is constant
4347 ** and will never change. It does not need to be destroyed. ^The
4348 ** SQLITE_TRANSIENT value means that the content will likely change in
4349 ** the near future and that SQLite should make its own private copy of
4350 ** the content before returning.
4351 **
4352 ** The typedef is necessary to work around problems in certain
4353 ** C++ compilers.
4354 */
4355 typedef void (*sqlite3_destructor_type)(void*);
4356 #define SQLITE_STATIC ((sqlite3_destructor_type)0)
4357 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
4358
4359 /*
4360 ** CAPI3REF: Setting The Result Of An SQL Function
4361 **
4362 ** These routines are used by the xFunc or xFinal callbacks that
4363 ** implement SQL functions and aggregates. See
4364 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
4365 ** for additional information.
4366 **
4367 ** These functions work very much like the [parameter binding] family of
4368 ** functions used to bind values to host parameters in prepared statements.
4369 ** Refer to the [SQL parameter] documentation for additional information.
4370 **
4371 ** ^The sqlite3_result_blob() interface sets the result from
4372 ** an application-defined function to be the BLOB whose content is pointed
4373 ** to by the second parameter and which is N bytes long where N is the
4374 ** third parameter.
4375 **
4376 ** ^The sqlite3_result_zeroblob() interfaces set the result of
4377 ** the application-defined function to be a BLOB containing all zero
4378 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
4379 **
4380 ** ^The sqlite3_result_double() interface sets the result from
4381 ** an application-defined function to be a floating point value specified
4382 ** by its 2nd argument.
4383 **
4384 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
4385 ** cause the implemented SQL function to throw an exception.
4386 ** ^SQLite uses the string pointed to by the
4387 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
4388 ** as the text of an error message. ^SQLite interprets the error
4389 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
4390 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
4391 ** byte order. ^If the third parameter to sqlite3_result_error()
4392 ** or sqlite3_result_error16() is negative then SQLite takes as the error
4393 ** message all text up through the first zero character.
4394 ** ^If the third parameter to sqlite3_result_error() or
4395 ** sqlite3_result_error16() is non-negative then SQLite takes that many
4396 ** bytes (not characters) from the 2nd parameter as the error message.
4397 ** ^The sqlite3_result_error() and sqlite3_result_error16()
4398 ** routines make a private copy of the error message text before
4399 ** they return. Hence, the calling function can deallocate or
4400 ** modify the text after they return without harm.
4401 ** ^The sqlite3_result_error_code() function changes the error code
4402 ** returned by SQLite as a result of an error in a function. ^By default,
4403 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
4404 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
4405 **
4406 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
4407 ** error indicating that a string or BLOB is too long to represent.
4408 **
4409 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
4410 ** error indicating that a memory allocation failed.
4411 **
4412 ** ^The sqlite3_result_int() interface sets the return value
4413 ** of the application-defined function to be the 32-bit signed integer
4414 ** value given in the 2nd argument.
4415 ** ^The sqlite3_result_int64() interface sets the return value
4416 ** of the application-defined function to be the 64-bit signed integer
4417 ** value given in the 2nd argument.
4418 **
4419 ** ^The sqlite3_result_null() interface sets the return value
4420 ** of the application-defined function to be NULL.
4421 **
4422 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
4423 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
4424 ** set the return value of the application-defined function to be
4425 ** a text string which is represented as UTF-8, UTF-16 native byte order,
4426 ** UTF-16 little endian, or UTF-16 big endian, respectively.
4427 ** ^SQLite takes the text result from the application from
4428 ** the 2nd parameter of the sqlite3_result_text* interfaces.
4429 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4430 ** is negative, then SQLite takes result text from the 2nd parameter
4431 ** through the first zero character.
4432 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4433 ** is non-negative, then as many bytes (not characters) of the text
4434 ** pointed to by the 2nd parameter are taken as the application-defined
4435 ** function result. If the 3rd parameter is non-negative, then it
4436 ** must be the byte offset into the string where the NUL terminator would
4437 ** appear if the string where NUL terminated. If any NUL characters occur
4438 ** in the string at a byte offset that is less than the value of the 3rd
4439 ** parameter, then the resulting string will contain embedded NULs and the
4440 ** result of expressions operating on strings with embedded NULs is undefined.
4441 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4442 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4443 ** function as the destructor on the text or BLOB result when it has
4444 ** finished using that result.
4445 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4446 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4447 ** assumes that the text or BLOB result is in constant space and does not
4448 ** copy the content of the parameter nor call a destructor on the content
4449 ** when it has finished using that result.
4450 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4451 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4452 ** then SQLite makes a copy of the result into space obtained from
4453 ** from [sqlite3_malloc()] before it returns.
4454 **
4455 ** ^The sqlite3_result_value() interface sets the result of
4456 ** the application-defined function to be a copy the
4457 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
4458 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4459 ** so that the [sqlite3_value] specified in the parameter may change or
4460 ** be deallocated after sqlite3_result_value() returns without harm.
4461 ** ^A [protected sqlite3_value] object may always be used where an
4462 ** [unprotected sqlite3_value] object is required, so either
4463 ** kind of [sqlite3_value] object can be used with this interface.
4464 **
4465 ** If these routines are called from within the different thread
4466 ** than the one containing the application-defined function that received
4467 ** the [sqlite3_context] pointer, the results are undefined.
4468 */
4469 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4470 SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
4471 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
4472 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
4473 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
4474 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
4475 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
4476 SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
4477 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4478 SQLITE_API void sqlite3_result_null(sqlite3_context*);
4479 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4480 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4481 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4482 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4483 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4484 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
4485
4486 /*
4487 ** CAPI3REF: Define New Collating Sequences
4488 **
4489 ** ^These functions add, remove, or modify a [collation] associated
4490 ** with the [database connection] specified as the first argument.
4491 **
4492 ** ^The name of the collation is a UTF-8 string
4493 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4494 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4495 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4496 ** considered to be the same name.
4497 **
4498 ** ^(The third argument (eTextRep) must be one of the constants:
4499 ** <ul>
4500 ** <li> [SQLITE_UTF8],
4501 ** <li> [SQLITE_UTF16LE],
4502 ** <li> [SQLITE_UTF16BE],
4503 ** <li> [SQLITE_UTF16], or
4504 ** <li> [SQLITE_UTF16_ALIGNED].
4505 ** </ul>)^
4506 ** ^The eTextRep argument determines the encoding of strings passed
4507 ** to the collating function callback, xCallback.
4508 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4509 ** force strings to be UTF16 with native byte order.
4510 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4511 ** on an even byte address.
4512 **
4513 ** ^The fourth argument, pArg, is an application data pointer that is passed
4514 ** through as the first argument to the collating function callback.
4515 **
4516 ** ^The fifth argument, xCallback, is a pointer to the collating function.
4517 ** ^Multiple collating functions can be registered using the same name but
4518 ** with different eTextRep parameters and SQLite will use whichever
4519 ** function requires the least amount of data transformation.
4520 ** ^If the xCallback argument is NULL then the collating function is
4521 ** deleted. ^When all collating functions having the same name are deleted,
4522 ** that collation is no longer usable.
4523 **
4524 ** ^The collating function callback is invoked with a copy of the pArg
4525 ** application data pointer and with two strings in the encoding specified
4526 ** by the eTextRep argument. The collating function must return an
4527 ** integer that is negative, zero, or positive
4528 ** if the first string is less than, equal to, or greater than the second,
4529 ** respectively. A collating function must always return the same answer
4530 ** given the same inputs. If two or more collating functions are registered
4531 ** to the same collation name (using different eTextRep values) then all
4532 ** must give an equivalent answer when invoked with equivalent strings.
4533 ** The collating function must obey the following properties for all
4534 ** strings A, B, and C:
4535 **
4536 ** <ol>
4537 ** <li> If A==B then B==A.
4538 ** <li> If A==B and B==C then A==C.
4539 ** <li> If A&lt;B THEN B&gt;A.
4540 ** <li> If A&lt;B and B&lt;C then A&lt;C.
4541 ** </ol>
4542 **
4543 ** If a collating function fails any of the above constraints and that
4544 ** collating function is registered and used, then the behavior of SQLite
4545 ** is undefined.
4546 **
4547 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4548 ** with the addition that the xDestroy callback is invoked on pArg when
4549 ** the collating function is deleted.
4550 ** ^Collating functions are deleted when they are overridden by later
4551 ** calls to the collation creation functions or when the
4552 ** [database connection] is closed using [sqlite3_close()].
4553 **
4554 ** ^The xDestroy callback is <u>not</u> called if the
4555 ** sqlite3_create_collation_v2() function fails. Applications that invoke
4556 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4557 ** check the return code and dispose of the application data pointer
4558 ** themselves rather than expecting SQLite to deal with it for them.
4559 ** This is different from every other SQLite interface. The inconsistency
4560 ** is unfortunate but cannot be changed without breaking backwards
4561 ** compatibility.
4562 **
4563 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4564 */
4565 SQLITE_API int sqlite3_create_collation(
4566 sqlite3*,
4567 const char *zName,
4568 int eTextRep,
4569 void *pArg,
4570 int(*xCompare)(void*,int,const void*,int,const void*)
4571 );
4572 SQLITE_API int sqlite3_create_collation_v2(
4573 sqlite3*,
4574 const char *zName,
4575 int eTextRep,
4576 void *pArg,
4577 int(*xCompare)(void*,int,const void*,int,const void*),
4578 void(*xDestroy)(void*)
4579 );
4580 SQLITE_API int sqlite3_create_collation16(
4581 sqlite3*,
4582 const void *zName,
4583 int eTextRep,
4584 void *pArg,
4585 int(*xCompare)(void*,int,const void*,int,const void*)
4586 );
4587
4588 /*
4589 ** CAPI3REF: Collation Needed Callbacks
4590 **
4591 ** ^To avoid having to register all collation sequences before a database
4592 ** can be used, a single callback function may be registered with the
4593 ** [database connection] to be invoked whenever an undefined collation
4594 ** sequence is required.
4595 **
4596 ** ^If the function is registered using the sqlite3_collation_needed() API,
4597 ** then it is passed the names of undefined collation sequences as strings
4598 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4599 ** the names are passed as UTF-16 in machine native byte order.
4600 ** ^A call to either function replaces the existing collation-needed callback.
4601 **
4602 ** ^(When the callback is invoked, the first argument passed is a copy
4603 ** of the second argument to sqlite3_collation_needed() or
4604 ** sqlite3_collation_needed16(). The second argument is the database
4605 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4606 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4607 ** sequence function required. The fourth parameter is the name of the
4608 ** required collation sequence.)^
4609 **
4610 ** The callback function should register the desired collation using
4611 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4612 ** [sqlite3_create_collation_v2()].
4613 */
4614 SQLITE_API int sqlite3_collation_needed(
4615 sqlite3*,
4616 void*,
4617 void(*)(void*,sqlite3*,int eTextRep,const char*)
4618 );
4619 SQLITE_API int sqlite3_collation_needed16(
4620 sqlite3*,
4621 void*,
4622 void(*)(void*,sqlite3*,int eTextRep,const void*)
4623 );
4624
4625 #ifdef SQLITE_HAS_CODEC
4626 /*
4627 ** Specify the key for an encrypted database. This routine should be
4628 ** called right after sqlite3_open().
4629 **
4630 ** The code to implement this API is not available in the public release
4631 ** of SQLite.
4632 */
4633 SQLITE_API int sqlite3_key(
4634 sqlite3 *db, /* Database to be rekeyed */
4635 const void *pKey, int nKey /* The key */
4636 );
4637 SQLITE_API int sqlite3_key_v2(
4638 sqlite3 *db, /* Database to be rekeyed */
4639 const char *zDbName, /* Name of the database */
4640 const void *pKey, int nKey /* The key */
4641 );
4642
4643 /*
4644 ** Change the key on an open database. If the current database is not
4645 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
4646 ** database is decrypted.
4647 **
4648 ** The code to implement this API is not available in the public release
4649 ** of SQLite.
4650 */
4651 SQLITE_API int sqlite3_rekey(
4652 sqlite3 *db, /* Database to be rekeyed */
4653 const void *pKey, int nKey /* The new key */
4654 );
4655 SQLITE_API int sqlite3_rekey_v2(
4656 sqlite3 *db, /* Database to be rekeyed */
4657 const char *zDbName, /* Name of the database */
4658 const void *pKey, int nKey /* The new key */
4659 );
4660
4661 /*
4662 ** Specify the activation key for a SEE database. Unless
4663 ** activated, none of the SEE routines will work.
4664 */
4665 SQLITE_API void sqlite3_activate_see(
4666 const char *zPassPhrase /* Activation phrase */
4667 );
4668 #endif
4669
4670 #ifdef SQLITE_ENABLE_CEROD
4671 /*
4672 ** Specify the activation key for a CEROD database. Unless
4673 ** activated, none of the CEROD routines will work.
4674 */
4675 SQLITE_API void sqlite3_activate_cerod(
4676 const char *zPassPhrase /* Activation phrase */
4677 );
4678 #endif
4679
4680 /*
4681 ** CAPI3REF: Suspend Execution For A Short Time
4682 **
4683 ** The sqlite3_sleep() function causes the current thread to suspend execution
4684 ** for at least a number of milliseconds specified in its parameter.
4685 **
4686 ** If the operating system does not support sleep requests with
4687 ** millisecond time resolution, then the time will be rounded up to
4688 ** the nearest second. The number of milliseconds of sleep actually
4689 ** requested from the operating system is returned.
4690 **
4691 ** ^SQLite implements this interface by calling the xSleep()
4692 ** method of the default [sqlite3_vfs] object. If the xSleep() method
4693 ** of the default VFS is not implemented correctly, or not implemented at
4694 ** all, then the behavior of sqlite3_sleep() may deviate from the description
4695 ** in the previous paragraphs.
4696 */
4697 SQLITE_API int sqlite3_sleep(int);
4698
4699 /*
4700 ** CAPI3REF: Name Of The Folder Holding Temporary Files
4701 **
4702 ** ^(If this global variable is made to point to a string which is
4703 ** the name of a folder (a.k.a. directory), then all temporary files
4704 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4705 ** will be placed in that directory.)^ ^If this variable
4706 ** is a NULL pointer, then SQLite performs a search for an appropriate
4707 ** temporary file directory.
4708 **
4709 ** It is not safe to read or modify this variable in more than one
4710 ** thread at a time. It is not safe to read or modify this variable
4711 ** if a [database connection] is being used at the same time in a separate
4712 ** thread.
4713 ** It is intended that this variable be set once
4714 ** as part of process initialization and before any SQLite interface
4715 ** routines have been called and that this variable remain unchanged
4716 ** thereafter.
4717 **
4718 ** ^The [temp_store_directory pragma] may modify this variable and cause
4719 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4720 ** the [temp_store_directory pragma] always assumes that any string
4721 ** that this variable points to is held in memory obtained from
4722 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4723 ** using [sqlite3_free].
4724 ** Hence, if this variable is modified directly, either it should be
4725 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4726 ** or else the use of the [temp_store_directory pragma] should be avoided.
4727 **
4728 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
4729 ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
4730 ** features that require the use of temporary files may fail. Here is an
4731 ** example of how to do this using C++ with the Windows Runtime:
4732 **
4733 ** <blockquote><pre>
4734 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
4735 ** &nbsp; TemporaryFolder->Path->Data();
4736 ** char zPathBuf&#91;MAX_PATH + 1&#93;;
4737 ** memset(zPathBuf, 0, sizeof(zPathBuf));
4738 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
4739 ** &nbsp; NULL, NULL);
4740 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
4741 ** </pre></blockquote>
4742 */
4743 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
4744
4745 /*
4746 ** CAPI3REF: Name Of The Folder Holding Database Files
4747 **
4748 ** ^(If this global variable is made to point to a string which is
4749 ** the name of a folder (a.k.a. directory), then all database files
4750 ** specified with a relative pathname and created or accessed by
4751 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
4752 ** to be relative to that directory.)^ ^If this variable is a NULL
4753 ** pointer, then SQLite assumes that all database files specified
4754 ** with a relative pathname are relative to the current directory
4755 ** for the process. Only the windows VFS makes use of this global
4756 ** variable; it is ignored by the unix VFS.
4757 **
4758 ** Changing the value of this variable while a database connection is
4759 ** open can result in a corrupt database.
4760 **
4761 ** It is not safe to read or modify this variable in more than one
4762 ** thread at a time. It is not safe to read or modify this variable
4763 ** if a [database connection] is being used at the same time in a separate
4764 ** thread.
4765 ** It is intended that this variable be set once
4766 ** as part of process initialization and before any SQLite interface
4767 ** routines have been called and that this variable remain unchanged
4768 ** thereafter.
4769 **
4770 ** ^The [data_store_directory pragma] may modify this variable and cause
4771 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4772 ** the [data_store_directory pragma] always assumes that any string
4773 ** that this variable points to is held in memory obtained from
4774 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4775 ** using [sqlite3_free].
4776 ** Hence, if this variable is modified directly, either it should be
4777 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4778 ** or else the use of the [data_store_directory pragma] should be avoided.
4779 */
4780 SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
4781
4782 /*
4783 ** CAPI3REF: Test For Auto-Commit Mode
4784 ** KEYWORDS: {autocommit mode}
4785 **
4786 ** ^The sqlite3_get_autocommit() interface returns non-zero or
4787 ** zero if the given database connection is or is not in autocommit mode,
4788 ** respectively. ^Autocommit mode is on by default.
4789 ** ^Autocommit mode is disabled by a [BEGIN] statement.
4790 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
4791 **
4792 ** If certain kinds of errors occur on a statement within a multi-statement
4793 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
4794 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
4795 ** transaction might be rolled back automatically. The only way to
4796 ** find out whether SQLite automatically rolled back the transaction after
4797 ** an error is to use this function.
4798 **
4799 ** If another thread changes the autocommit status of the database
4800 ** connection while this routine is running, then the return value
4801 ** is undefined.
4802 */
4803 SQLITE_API int sqlite3_get_autocommit(sqlite3*);
4804
4805 /*
4806 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
4807 **
4808 ** ^The sqlite3_db_handle interface returns the [database connection] handle
4809 ** to which a [prepared statement] belongs. ^The [database connection]
4810 ** returned by sqlite3_db_handle is the same [database connection]
4811 ** that was the first argument
4812 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
4813 ** create the statement in the first place.
4814 */
4815 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
4816
4817 /*
4818 ** CAPI3REF: Return The Filename For A Database Connection
4819 **
4820 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
4821 ** associated with database N of connection D. ^The main database file
4822 ** has the name "main". If there is no attached database N on the database
4823 ** connection D, or if database N is a temporary or in-memory database, then
4824 ** a NULL pointer is returned.
4825 **
4826 ** ^The filename returned by this function is the output of the
4827 ** xFullPathname method of the [VFS]. ^In other words, the filename
4828 ** will be an absolute pathname, even if the filename used
4829 ** to open the database originally was a URI or relative pathname.
4830 */
4831 SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
4832
4833 /*
4834 ** CAPI3REF: Determine if a database is read-only
4835 **
4836 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
4837 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
4838 ** the name of a database on connection D.
4839 */
4840 SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
4841
4842 /*
4843 ** CAPI3REF: Find the next prepared statement
4844 **
4845 ** ^This interface returns a pointer to the next [prepared statement] after
4846 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
4847 ** then this interface returns a pointer to the first prepared statement
4848 ** associated with the database connection pDb. ^If no prepared statement
4849 ** satisfies the conditions of this routine, it returns NULL.
4850 **
4851 ** The [database connection] pointer D in a call to
4852 ** [sqlite3_next_stmt(D,S)] must refer to an open database
4853 ** connection and in particular must not be a NULL pointer.
4854 */
4855 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
4856
4857 /*
4858 ** CAPI3REF: Commit And Rollback Notification Callbacks
4859 **
4860 ** ^The sqlite3_commit_hook() interface registers a callback
4861 ** function to be invoked whenever a transaction is [COMMIT | committed].
4862 ** ^Any callback set by a previous call to sqlite3_commit_hook()
4863 ** for the same database connection is overridden.
4864 ** ^The sqlite3_rollback_hook() interface registers a callback
4865 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
4866 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
4867 ** for the same database connection is overridden.
4868 ** ^The pArg argument is passed through to the callback.
4869 ** ^If the callback on a commit hook function returns non-zero,
4870 ** then the commit is converted into a rollback.
4871 **
4872 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
4873 ** return the P argument from the previous call of the same function
4874 ** on the same [database connection] D, or NULL for
4875 ** the first call for each function on D.
4876 **
4877 ** The commit and rollback hook callbacks are not reentrant.
4878 ** The callback implementation must not do anything that will modify
4879 ** the database connection that invoked the callback. Any actions
4880 ** to modify the database connection must be deferred until after the
4881 ** completion of the [sqlite3_step()] call that triggered the commit
4882 ** or rollback hook in the first place.
4883 ** Note that running any other SQL statements, including SELECT statements,
4884 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
4885 ** the database connections for the meaning of "modify" in this paragraph.
4886 **
4887 ** ^Registering a NULL function disables the callback.
4888 **
4889 ** ^When the commit hook callback routine returns zero, the [COMMIT]
4890 ** operation is allowed to continue normally. ^If the commit hook
4891 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
4892 ** ^The rollback hook is invoked on a rollback that results from a commit
4893 ** hook returning non-zero, just as it would be with any other rollback.
4894 **
4895 ** ^For the purposes of this API, a transaction is said to have been
4896 ** rolled back if an explicit "ROLLBACK" statement is executed, or
4897 ** an error or constraint causes an implicit rollback to occur.
4898 ** ^The rollback callback is not invoked if a transaction is
4899 ** automatically rolled back because the database connection is closed.
4900 **
4901 ** See also the [sqlite3_update_hook()] interface.
4902 */
4903 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
4904 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
4905
4906 /*
4907 ** CAPI3REF: Data Change Notification Callbacks
4908 **
4909 ** ^The sqlite3_update_hook() interface registers a callback function
4910 ** with the [database connection] identified by the first argument
4911 ** to be invoked whenever a row is updated, inserted or deleted in
4912 ** a rowid table.
4913 ** ^Any callback set by a previous call to this function
4914 ** for the same database connection is overridden.
4915 **
4916 ** ^The second argument is a pointer to the function to invoke when a
4917 ** row is updated, inserted or deleted in a rowid table.
4918 ** ^The first argument to the callback is a copy of the third argument
4919 ** to sqlite3_update_hook().
4920 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
4921 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
4922 ** to be invoked.
4923 ** ^The third and fourth arguments to the callback contain pointers to the
4924 ** database and table name containing the affected row.
4925 ** ^The final callback parameter is the [rowid] of the row.
4926 ** ^In the case of an update, this is the [rowid] after the update takes place.
4927 **
4928 ** ^(The update hook is not invoked when internal system tables are
4929 ** modified (i.e. sqlite_master and sqlite_sequence).)^
4930 ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
4931 **
4932 ** ^In the current implementation, the update hook
4933 ** is not invoked when duplication rows are deleted because of an
4934 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
4935 ** invoked when rows are deleted using the [truncate optimization].
4936 ** The exceptions defined in this paragraph might change in a future
4937 ** release of SQLite.
4938 **
4939 ** The update hook implementation must not do anything that will modify
4940 ** the database connection that invoked the update hook. Any actions
4941 ** to modify the database connection must be deferred until after the
4942 ** completion of the [sqlite3_step()] call that triggered the update hook.
4943 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
4944 ** database connections for the meaning of "modify" in this paragraph.
4945 **
4946 ** ^The sqlite3_update_hook(D,C,P) function
4947 ** returns the P argument from the previous call
4948 ** on the same [database connection] D, or NULL for
4949 ** the first call on D.
4950 **
4951 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
4952 ** interfaces.
4953 */
4954 SQLITE_API void *sqlite3_update_hook(
4955 sqlite3*,
4956 void(*)(void *,int ,char const *,char const *,sqlite3_int64),
4957 void*
4958 );
4959
4960 /*
4961 ** CAPI3REF: Enable Or Disable Shared Pager Cache
4962 **
4963 ** ^(This routine enables or disables the sharing of the database cache
4964 ** and schema data structures between [database connection | connections]
4965 ** to the same database. Sharing is enabled if the argument is true
4966 ** and disabled if the argument is false.)^
4967 **
4968 ** ^Cache sharing is enabled and disabled for an entire process.
4969 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
4970 ** sharing was enabled or disabled for each thread separately.
4971 **
4972 ** ^(The cache sharing mode set by this interface effects all subsequent
4973 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
4974 ** Existing database connections continue use the sharing mode
4975 ** that was in effect at the time they were opened.)^
4976 **
4977 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
4978 ** successfully. An [error code] is returned otherwise.)^
4979 **
4980 ** ^Shared cache is disabled by default. But this might change in
4981 ** future releases of SQLite. Applications that care about shared
4982 ** cache setting should set it explicitly.
4983 **
4984 ** This interface is threadsafe on processors where writing a
4985 ** 32-bit integer is atomic.
4986 **
4987 ** See Also: [SQLite Shared-Cache Mode]
4988 */
4989 SQLITE_API int sqlite3_enable_shared_cache(int);
4990
4991 /*
4992 ** CAPI3REF: Attempt To Free Heap Memory
4993 **
4994 ** ^The sqlite3_release_memory() interface attempts to free N bytes
4995 ** of heap memory by deallocating non-essential memory allocations
4996 ** held by the database library. Memory used to cache database
4997 ** pages to improve performance is an example of non-essential memory.
4998 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
4999 ** which might be more or less than the amount requested.
5000 ** ^The sqlite3_release_memory() routine is a no-op returning zero
5001 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5002 **
5003 ** See also: [sqlite3_db_release_memory()]
5004 */
5005 SQLITE_API int sqlite3_release_memory(int);
5006
5007 /*
5008 ** CAPI3REF: Free Memory Used By A Database Connection
5009 **
5010 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
5011 ** memory as possible from database connection D. Unlike the
5012 ** [sqlite3_release_memory()] interface, this interface is in effect even
5013 ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
5014 ** omitted.
5015 **
5016 ** See also: [sqlite3_release_memory()]
5017 */
5018 SQLITE_API int sqlite3_db_release_memory(sqlite3*);
5019
5020 /*
5021 ** CAPI3REF: Impose A Limit On Heap Size
5022 **
5023 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
5024 ** soft limit on the amount of heap memory that may be allocated by SQLite.
5025 ** ^SQLite strives to keep heap memory utilization below the soft heap
5026 ** limit by reducing the number of pages held in the page cache
5027 ** as heap memory usages approaches the limit.
5028 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
5029 ** below the limit, it will exceed the limit rather than generate
5030 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
5031 ** is advisory only.
5032 **
5033 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
5034 ** the soft heap limit prior to the call, or negative in the case of an
5035 ** error. ^If the argument N is negative
5036 ** then no change is made to the soft heap limit. Hence, the current
5037 ** size of the soft heap limit can be determined by invoking
5038 ** sqlite3_soft_heap_limit64() with a negative argument.
5039 **
5040 ** ^If the argument N is zero then the soft heap limit is disabled.
5041 **
5042 ** ^(The soft heap limit is not enforced in the current implementation
5043 ** if one or more of following conditions are true:
5044 **
5045 ** <ul>
5046 ** <li> The soft heap limit is set to zero.
5047 ** <li> Memory accounting is disabled using a combination of the
5048 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
5049 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
5050 ** <li> An alternative page cache implementation is specified using
5051 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
5052 ** <li> The page cache allocates from its own memory pool supplied
5053 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
5054 ** from the heap.
5055 ** </ul>)^
5056 **
5057 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
5058 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
5059 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
5060 ** the soft heap limit is enforced on every memory allocation. Without
5061 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
5062 ** when memory is allocated by the page cache. Testing suggests that because
5063 ** the page cache is the predominate memory user in SQLite, most
5064 ** applications will achieve adequate soft heap limit enforcement without
5065 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5066 **
5067 ** The circumstances under which SQLite will enforce the soft heap limit may
5068 ** changes in future releases of SQLite.
5069 */
5070 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
5071
5072 /*
5073 ** CAPI3REF: Deprecated Soft Heap Limit Interface
5074 ** DEPRECATED
5075 **
5076 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
5077 ** interface. This routine is provided for historical compatibility
5078 ** only. All new applications should use the
5079 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
5080 */
5081 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
5082
5083
5084 /*
5085 ** CAPI3REF: Extract Metadata About A Column Of A Table
5086 **
5087 ** ^This routine returns metadata about a specific column of a specific
5088 ** database table accessible using the [database connection] handle
5089 ** passed as the first function argument.
5090 **
5091 ** ^The column is identified by the second, third and fourth parameters to
5092 ** this function. ^The second parameter is either the name of the database
5093 ** (i.e. "main", "temp", or an attached database) containing the specified
5094 ** table or NULL. ^If it is NULL, then all attached databases are searched
5095 ** for the table using the same algorithm used by the database engine to
5096 ** resolve unqualified table references.
5097 **
5098 ** ^The third and fourth parameters to this function are the table and column
5099 ** name of the desired column, respectively. Neither of these parameters
5100 ** may be NULL.
5101 **
5102 ** ^Metadata is returned by writing to the memory locations passed as the 5th
5103 ** and subsequent parameters to this function. ^Any of these arguments may be
5104 ** NULL, in which case the corresponding element of metadata is omitted.
5105 **
5106 ** ^(<blockquote>
5107 ** <table border="1">
5108 ** <tr><th> Parameter <th> Output<br>Type <th> Description
5109 **
5110 ** <tr><td> 5th <td> const char* <td> Data type
5111 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
5112 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
5113 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
5114 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
5115 ** </table>
5116 ** </blockquote>)^
5117 **
5118 ** ^The memory pointed to by the character pointers returned for the
5119 ** declaration type and collation sequence is valid only until the next
5120 ** call to any SQLite API function.
5121 **
5122 ** ^If the specified table is actually a view, an [error code] is returned.
5123 **
5124 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an
5125 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
5126 ** parameters are set for the explicitly declared column. ^(If there is no
5127 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
5128 ** parameters are set as follows:
5129 **
5130 ** <pre>
5131 ** data type: "INTEGER"
5132 ** collation sequence: "BINARY"
5133 ** not null: 0
5134 ** primary key: 1
5135 ** auto increment: 0
5136 ** </pre>)^
5137 **
5138 ** ^(This function may load one or more schemas from database files. If an
5139 ** error occurs during this process, or if the requested table or column
5140 ** cannot be found, an [error code] is returned and an error message left
5141 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
5142 **
5143 ** ^This API is only available if the library was compiled with the
5144 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
5145 */
5146 SQLITE_API int sqlite3_table_column_metadata(
5147 sqlite3 *db, /* Connection handle */
5148 const char *zDbName, /* Database name or NULL */
5149 const char *zTableName, /* Table name */
5150 const char *zColumnName, /* Column name */
5151 char const **pzDataType, /* OUTPUT: Declared data type */
5152 char const **pzCollSeq, /* OUTPUT: Collation sequence name */
5153 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
5154 int *pPrimaryKey, /* OUTPUT: True if column part of PK */
5155 int *pAutoinc /* OUTPUT: True if column is auto-increment */
5156 );
5157
5158 /*
5159 ** CAPI3REF: Load An Extension
5160 **
5161 ** ^This interface loads an SQLite extension library from the named file.
5162 **
5163 ** ^The sqlite3_load_extension() interface attempts to load an
5164 ** [SQLite extension] library contained in the file zFile. If
5165 ** the file cannot be loaded directly, attempts are made to load
5166 ** with various operating-system specific extensions added.
5167 ** So for example, if "samplelib" cannot be loaded, then names like
5168 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
5169 ** be tried also.
5170 **
5171 ** ^The entry point is zProc.
5172 ** ^(zProc may be 0, in which case SQLite will try to come up with an
5173 ** entry point name on its own. It first tries "sqlite3_extension_init".
5174 ** If that does not work, it constructs a name "sqlite3_X_init" where the
5175 ** X is consists of the lower-case equivalent of all ASCII alphabetic
5176 ** characters in the filename from the last "/" to the first following
5177 ** "." and omitting any initial "lib".)^
5178 ** ^The sqlite3_load_extension() interface returns
5179 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
5180 ** ^If an error occurs and pzErrMsg is not 0, then the
5181 ** [sqlite3_load_extension()] interface shall attempt to
5182 ** fill *pzErrMsg with error message text stored in memory
5183 ** obtained from [sqlite3_malloc()]. The calling function
5184 ** should free this memory by calling [sqlite3_free()].
5185 **
5186 ** ^Extension loading must be enabled using
5187 ** [sqlite3_enable_load_extension()] prior to calling this API,
5188 ** otherwise an error will be returned.
5189 **
5190 ** See also the [load_extension() SQL function].
5191 */
5192 SQLITE_API int sqlite3_load_extension(
5193 sqlite3 *db, /* Load the extension into this database connection */
5194 const char *zFile, /* Name of the shared library containing extension */
5195 const char *zProc, /* Entry point. Derived from zFile if 0 */
5196 char **pzErrMsg /* Put error message here if not 0 */
5197 );
5198
5199 /*
5200 ** CAPI3REF: Enable Or Disable Extension Loading
5201 **
5202 ** ^So as not to open security holes in older applications that are
5203 ** unprepared to deal with [extension loading], and as a means of disabling
5204 ** [extension loading] while evaluating user-entered SQL, the following API
5205 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5206 **
5207 ** ^Extension loading is off by default.
5208 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5209 ** to turn extension loading on and call it with onoff==0 to turn
5210 ** it back off again.
5211 */
5212 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
5213
5214 /*
5215 ** CAPI3REF: Automatically Load Statically Linked Extensions
5216 **
5217 ** ^This interface causes the xEntryPoint() function to be invoked for
5218 ** each new [database connection] that is created. The idea here is that
5219 ** xEntryPoint() is the entry point for a statically linked [SQLite extension]
5220 ** that is to be automatically loaded into all new database connections.
5221 **
5222 ** ^(Even though the function prototype shows that xEntryPoint() takes
5223 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
5224 ** arguments and expects and integer result as if the signature of the
5225 ** entry point where as follows:
5226 **
5227 ** <blockquote><pre>
5228 ** &nbsp; int xEntryPoint(
5229 ** &nbsp; sqlite3 *db,
5230 ** &nbsp; const char **pzErrMsg,
5231 ** &nbsp; const struct sqlite3_api_routines *pThunk
5232 ** &nbsp; );
5233 ** </pre></blockquote>)^
5234 **
5235 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
5236 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
5237 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
5238 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
5239 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
5240 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
5241 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
5242 **
5243 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
5244 ** on the list of automatic extensions is a harmless no-op. ^No entry point
5245 ** will be called more than once for each database connection that is opened.
5246 **
5247 ** See also: [sqlite3_reset_auto_extension()]
5248 ** and [sqlite3_cancel_auto_extension()]
5249 */
5250 SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void));
5251
5252 /*
5253 ** CAPI3REF: Cancel Automatic Extension Loading
5254 **
5255 ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
5256 ** initialization routine X that was registered using a prior call to
5257 ** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)]
5258 ** routine returns 1 if initialization routine X was successfully
5259 ** unregistered and it returns 0 if X was not on the list of initialization
5260 ** routines.
5261 */
5262 SQLITE_API int sqlite3_cancel_auto_extension(void (*xEntryPoint)(void));
5263
5264 /*
5265 ** CAPI3REF: Reset Automatic Extension Loading
5266 **
5267 ** ^This interface disables all automatic extensions previously
5268 ** registered using [sqlite3_auto_extension()].
5269 */
5270 SQLITE_API void sqlite3_reset_auto_extension(void);
5271
5272 /*
5273 ** The interface to the virtual-table mechanism is currently considered
5274 ** to be experimental. The interface might change in incompatible ways.
5275 ** If this is a problem for you, do not use the interface at this time.
5276 **
5277 ** When the virtual-table mechanism stabilizes, we will declare the
5278 ** interface fixed, support it indefinitely, and remove this comment.
5279 */
5280
5281 /*
5282 ** Structures used by the virtual table interface
5283 */
5284 typedef struct sqlite3_vtab sqlite3_vtab;
5285 typedef struct sqlite3_index_info sqlite3_index_info;
5286 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
5287 typedef struct sqlite3_module sqlite3_module;
5288
5289 /*
5290 ** CAPI3REF: Virtual Table Object
5291 ** KEYWORDS: sqlite3_module {virtual table module}
5292 **
5293 ** This structure, sometimes called a "virtual table module",
5294 ** defines the implementation of a [virtual tables].
5295 ** This structure consists mostly of methods for the module.
5296 **
5297 ** ^A virtual table module is created by filling in a persistent
5298 ** instance of this structure and passing a pointer to that instance
5299 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
5300 ** ^The registration remains valid until it is replaced by a different
5301 ** module or until the [database connection] closes. The content
5302 ** of this structure must not change while it is registered with
5303 ** any database connection.
5304 */
5305 struct sqlite3_module {
5306 int iVersion;
5307 int (*xCreate)(sqlite3*, void *pAux,
5308 int argc, const char *const*argv,
5309 sqlite3_vtab **ppVTab, char**);
5310 int (*xConnect)(sqlite3*, void *pAux,
5311 int argc, const char *const*argv,
5312 sqlite3_vtab **ppVTab, char**);
5313 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
5314 int (*xDisconnect)(sqlite3_vtab *pVTab);
5315 int (*xDestroy)(sqlite3_vtab *pVTab);
5316 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
5317 int (*xClose)(sqlite3_vtab_cursor*);
5318 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
5319 int argc, sqlite3_value **argv);
5320 int (*xNext)(sqlite3_vtab_cursor*);
5321 int (*xEof)(sqlite3_vtab_cursor*);
5322 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
5323 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
5324 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
5325 int (*xBegin)(sqlite3_vtab *pVTab);
5326 int (*xSync)(sqlite3_vtab *pVTab);
5327 int (*xCommit)(sqlite3_vtab *pVTab);
5328 int (*xRollback)(sqlite3_vtab *pVTab);
5329 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
5330 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
5331 void **ppArg);
5332 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
5333 /* The methods above are in version 1 of the sqlite_module object. Those
5334 ** below are for version 2 and greater. */
5335 int (*xSavepoint)(sqlite3_vtab *pVTab, int);
5336 int (*xRelease)(sqlite3_vtab *pVTab, int);
5337 int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
5338 };
5339
5340 /*
5341 ** CAPI3REF: Virtual Table Indexing Information
5342 ** KEYWORDS: sqlite3_index_info
5343 **
5344 ** The sqlite3_index_info structure and its substructures is used as part
5345 ** of the [virtual table] interface to
5346 ** pass information into and receive the reply from the [xBestIndex]
5347 ** method of a [virtual table module]. The fields under **Inputs** are the
5348 ** inputs to xBestIndex and are read-only. xBestIndex inserts its
5349 ** results into the **Outputs** fields.
5350 **
5351 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
5352 **
5353 ** <blockquote>column OP expr</blockquote>
5354 **
5355 ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^ ^(The particular operator is
5356 ** stored in aConstraint[].op using one of the
5357 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
5358 ** ^(The index of the column is stored in
5359 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
5360 ** expr on the right-hand side can be evaluated (and thus the constraint
5361 ** is usable) and false if it cannot.)^
5362 **
5363 ** ^The optimizer automatically inverts terms of the form "expr OP column"
5364 ** and makes other simplifications to the WHERE clause in an attempt to
5365 ** get as many WHERE clause terms into the form shown above as possible.
5366 ** ^The aConstraint[] array only reports WHERE clause terms that are
5367 ** relevant to the particular virtual table being queried.
5368 **
5369 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
5370 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
5371 **
5372 ** The [xBestIndex] method must fill aConstraintUsage[] with information
5373 ** about what parameters to pass to xFilter. ^If argvIndex>0 then
5374 ** the right-hand side of the corresponding aConstraint[] is evaluated
5375 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
5376 ** is true, then the constraint is assumed to be fully handled by the
5377 ** virtual table and is not checked again by SQLite.)^
5378 **
5379 ** ^The idxNum and idxPtr values are recorded and passed into the
5380 ** [xFilter] method.
5381 ** ^[sqlite3_free()] is used to free idxPtr if and only if
5382 ** needToFreeIdxPtr is true.
5383 **
5384 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
5385 ** the correct order to satisfy the ORDER BY clause so that no separate
5386 ** sorting step is required.
5387 **
5388 ** ^The estimatedCost value is an estimate of the cost of a particular
5389 ** strategy. A cost of N indicates that the cost of the strategy is similar
5390 ** to a linear scan of an SQLite table with N rows. A cost of log(N)
5391 ** indicates that the expense of the operation is similar to that of a
5392 ** binary search on a unique indexed field of an SQLite table with N rows.
5393 **
5394 ** ^The estimatedRows value is an estimate of the number of rows that
5395 ** will be returned by the strategy.
5396 **
5397 ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
5398 ** structure for SQLite version 3.8.2. If a virtual table extension is
5399 ** used with an SQLite version earlier than 3.8.2, the results of attempting
5400 ** to read or write the estimatedRows field are undefined (but are likely
5401 ** to included crashing the application). The estimatedRows field should
5402 ** therefore only be used if [sqlite3_libversion_number()] returns a
5403 ** value greater than or equal to 3008002.
5404 */
5405 struct sqlite3_index_info {
5406 /* Inputs */
5407 int nConstraint; /* Number of entries in aConstraint */
5408 struct sqlite3_index_constraint {
5409 int iColumn; /* Column on left-hand side of constraint */
5410 unsigned char op; /* Constraint operator */
5411 unsigned char usable; /* True if this constraint is usable */
5412 int iTermOffset; /* Used internally - xBestIndex should ignore */
5413 } *aConstraint; /* Table of WHERE clause constraints */
5414 int nOrderBy; /* Number of terms in the ORDER BY clause */
5415 struct sqlite3_index_orderby {
5416 int iColumn; /* Column number */
5417 unsigned char desc; /* True for DESC. False for ASC. */
5418 } *aOrderBy; /* The ORDER BY clause */
5419 /* Outputs */
5420 struct sqlite3_index_constraint_usage {
5421 int argvIndex; /* if >0, constraint is part of argv to xFilter */
5422 unsigned char omit; /* Do not code a test for this constraint */
5423 } *aConstraintUsage;
5424 int idxNum; /* Number used to identify the index */
5425 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
5426 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
5427 int orderByConsumed; /* True if output is already ordered */
5428 double estimatedCost; /* Estimated cost of using this index */
5429 /* Fields below are only available in SQLite 3.8.2 and later */
5430 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */
5431 };
5432
5433 /*
5434 ** CAPI3REF: Virtual Table Constraint Operator Codes
5435 **
5436 ** These macros defined the allowed values for the
5437 ** [sqlite3_index_info].aConstraint[].op field. Each value represents
5438 ** an operator that is part of a constraint term in the wHERE clause of
5439 ** a query that uses a [virtual table].
5440 */
5441 #define SQLITE_INDEX_CONSTRAINT_EQ 2
5442 #define SQLITE_INDEX_CONSTRAINT_GT 4
5443 #define SQLITE_INDEX_CONSTRAINT_LE 8
5444 #define SQLITE_INDEX_CONSTRAINT_LT 16
5445 #define SQLITE_INDEX_CONSTRAINT_GE 32
5446 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
5447
5448 /*
5449 ** CAPI3REF: Register A Virtual Table Implementation
5450 **
5451 ** ^These routines are used to register a new [virtual table module] name.
5452 ** ^Module names must be registered before
5453 ** creating a new [virtual table] using the module and before using a
5454 ** preexisting [virtual table] for the module.
5455 **
5456 ** ^The module name is registered on the [database connection] specified
5457 ** by the first parameter. ^The name of the module is given by the
5458 ** second parameter. ^The third parameter is a pointer to
5459 ** the implementation of the [virtual table module]. ^The fourth
5460 ** parameter is an arbitrary client data pointer that is passed through
5461 ** into the [xCreate] and [xConnect] methods of the virtual table module
5462 ** when a new virtual table is be being created or reinitialized.
5463 **
5464 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
5465 ** is a pointer to a destructor for the pClientData. ^SQLite will
5466 ** invoke the destructor function (if it is not NULL) when SQLite
5467 ** no longer needs the pClientData pointer. ^The destructor will also
5468 ** be invoked if the call to sqlite3_create_module_v2() fails.
5469 ** ^The sqlite3_create_module()
5470 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
5471 ** destructor.
5472 */
5473 SQLITE_API int sqlite3_create_module(
5474 sqlite3 *db, /* SQLite connection to register module with */
5475 const char *zName, /* Name of the module */
5476 const sqlite3_module *p, /* Methods for the module */
5477 void *pClientData /* Client data for xCreate/xConnect */
5478 );
5479 SQLITE_API int sqlite3_create_module_v2(
5480 sqlite3 *db, /* SQLite connection to register module with */
5481 const char *zName, /* Name of the module */
5482 const sqlite3_module *p, /* Methods for the module */
5483 void *pClientData, /* Client data for xCreate/xConnect */
5484 void(*xDestroy)(void*) /* Module destructor function */
5485 );
5486
5487 /*
5488 ** CAPI3REF: Virtual Table Instance Object
5489 ** KEYWORDS: sqlite3_vtab
5490 **
5491 ** Every [virtual table module] implementation uses a subclass
5492 ** of this object to describe a particular instance
5493 ** of the [virtual table]. Each subclass will
5494 ** be tailored to the specific needs of the module implementation.
5495 ** The purpose of this superclass is to define certain fields that are
5496 ** common to all module implementations.
5497 **
5498 ** ^Virtual tables methods can set an error message by assigning a
5499 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
5500 ** take care that any prior string is freed by a call to [sqlite3_free()]
5501 ** prior to assigning a new string to zErrMsg. ^After the error message
5502 ** is delivered up to the client application, the string will be automatically
5503 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
5504 */
5505 struct sqlite3_vtab {
5506 const sqlite3_module *pModule; /* The module for this virtual table */
5507 int nRef; /* NO LONGER USED */
5508 char *zErrMsg; /* Error message from sqlite3_mprintf() */
5509 /* Virtual table implementations will typically add additional fields */
5510 };
5511
5512 /*
5513 ** CAPI3REF: Virtual Table Cursor Object
5514 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
5515 **
5516 ** Every [virtual table module] implementation uses a subclass of the
5517 ** following structure to describe cursors that point into the
5518 ** [virtual table] and are used
5519 ** to loop through the virtual table. Cursors are created using the
5520 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
5521 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
5522 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
5523 ** of the module. Each module implementation will define
5524 ** the content of a cursor structure to suit its own needs.
5525 **
5526 ** This superclass exists in order to define fields of the cursor that
5527 ** are common to all implementations.
5528 */
5529 struct sqlite3_vtab_cursor {
5530 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
5531 /* Virtual table implementations will typically add additional fields */
5532 };
5533
5534 /*
5535 ** CAPI3REF: Declare The Schema Of A Virtual Table
5536 **
5537 ** ^The [xCreate] and [xConnect] methods of a
5538 ** [virtual table module] call this interface
5539 ** to declare the format (the names and datatypes of the columns) of
5540 ** the virtual tables they implement.
5541 */
5542 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
5543
5544 /*
5545 ** CAPI3REF: Overload A Function For A Virtual Table
5546 **
5547 ** ^(Virtual tables can provide alternative implementations of functions
5548 ** using the [xFindFunction] method of the [virtual table module].
5549 ** But global versions of those functions
5550 ** must exist in order to be overloaded.)^
5551 **
5552 ** ^(This API makes sure a global version of a function with a particular
5553 ** name and number of parameters exists. If no such function exists
5554 ** before this API is called, a new function is created.)^ ^The implementation
5555 ** of the new function always causes an exception to be thrown. So
5556 ** the new function is not good for anything by itself. Its only
5557 ** purpose is to be a placeholder function that can be overloaded
5558 ** by a [virtual table].
5559 */
5560 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
5561
5562 /*
5563 ** The interface to the virtual-table mechanism defined above (back up
5564 ** to a comment remarkably similar to this one) is currently considered
5565 ** to be experimental. The interface might change in incompatible ways.
5566 ** If this is a problem for you, do not use the interface at this time.
5567 **
5568 ** When the virtual-table mechanism stabilizes, we will declare the
5569 ** interface fixed, support it indefinitely, and remove this comment.
5570 */
5571
5572 /*
5573 ** CAPI3REF: A Handle To An Open BLOB
5574 ** KEYWORDS: {BLOB handle} {BLOB handles}
5575 **
5576 ** An instance of this object represents an open BLOB on which
5577 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
5578 ** ^Objects of this type are created by [sqlite3_blob_open()]
5579 ** and destroyed by [sqlite3_blob_close()].
5580 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
5581 ** can be used to read or write small subsections of the BLOB.
5582 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
5583 */
5584 typedef struct sqlite3_blob sqlite3_blob;
5585
5586 /*
5587 ** CAPI3REF: Open A BLOB For Incremental I/O
5588 **
5589 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
5590 ** in row iRow, column zColumn, table zTable in database zDb;
5591 ** in other words, the same BLOB that would be selected by:
5592 **
5593 ** <pre>
5594 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
5595 ** </pre>)^
5596 **
5597 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
5598 ** and write access. ^If it is zero, the BLOB is opened for read access.
5599 ** ^It is not possible to open a column that is part of an index or primary
5600 ** key for writing. ^If [foreign key constraints] are enabled, it is
5601 ** not possible to open a column that is part of a [child key] for writing.
5602 **
5603 ** ^Note that the database name is not the filename that contains
5604 ** the database but rather the symbolic name of the database that
5605 ** appears after the AS keyword when the database is connected using [ATTACH].
5606 ** ^For the main database file, the database name is "main".
5607 ** ^For TEMP tables, the database name is "temp".
5608 **
5609 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
5610 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
5611 ** to be a null pointer.)^
5612 ** ^This function sets the [database connection] error code and message
5613 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
5614 ** functions. ^Note that the *ppBlob variable is always initialized in a
5615 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
5616 ** regardless of the success or failure of this routine.
5617 **
5618 ** ^(If the row that a BLOB handle points to is modified by an
5619 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
5620 ** then the BLOB handle is marked as "expired".
5621 ** This is true if any column of the row is changed, even a column
5622 ** other than the one the BLOB handle is open on.)^
5623 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
5624 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
5625 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
5626 ** rolled back by the expiration of the BLOB. Such changes will eventually
5627 ** commit if the transaction continues to completion.)^
5628 **
5629 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
5630 ** the opened blob. ^The size of a blob may not be changed by this
5631 ** interface. Use the [UPDATE] SQL command to change the size of a
5632 ** blob.
5633 **
5634 ** ^The [sqlite3_blob_open()] interface will fail for a [WITHOUT ROWID]
5635 ** table. Incremental BLOB I/O is not possible on [WITHOUT ROWID] tables.
5636 **
5637 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
5638 ** and the built-in [zeroblob] SQL function can be used, if desired,
5639 ** to create an empty, zero-filled blob in which to read or write using
5640 ** this interface.
5641 **
5642 ** To avoid a resource leak, every open [BLOB handle] should eventually
5643 ** be released by a call to [sqlite3_blob_close()].
5644 */
5645 SQLITE_API int sqlite3_blob_open(
5646 sqlite3*,
5647 const char *zDb,
5648 const char *zTable,
5649 const char *zColumn,
5650 sqlite3_int64 iRow,
5651 int flags,
5652 sqlite3_blob **ppBlob
5653 );
5654
5655 /*
5656 ** CAPI3REF: Move a BLOB Handle to a New Row
5657 **
5658 ** ^This function is used to move an existing blob handle so that it points
5659 ** to a different row of the same database table. ^The new row is identified
5660 ** by the rowid value passed as the second argument. Only the row can be
5661 ** changed. ^The database, table and column on which the blob handle is open
5662 ** remain the same. Moving an existing blob handle to a new row can be
5663 ** faster than closing the existing handle and opening a new one.
5664 **
5665 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
5666 ** it must exist and there must be either a blob or text value stored in
5667 ** the nominated column.)^ ^If the new row is not present in the table, or if
5668 ** it does not contain a blob or text value, or if another error occurs, an
5669 ** SQLite error code is returned and the blob handle is considered aborted.
5670 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
5671 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
5672 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
5673 ** always returns zero.
5674 **
5675 ** ^This function sets the database handle error code and message.
5676 */
5677 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
5678
5679 /*
5680 ** CAPI3REF: Close A BLOB Handle
5681 **
5682 ** ^Closes an open [BLOB handle].
5683 **
5684 ** ^Closing a BLOB shall cause the current transaction to commit
5685 ** if there are no other BLOBs, no pending prepared statements, and the
5686 ** database connection is in [autocommit mode].
5687 ** ^If any writes were made to the BLOB, they might be held in cache
5688 ** until the close operation if they will fit.
5689 **
5690 ** ^(Closing the BLOB often forces the changes
5691 ** out to disk and so if any I/O errors occur, they will likely occur
5692 ** at the time when the BLOB is closed. Any errors that occur during
5693 ** closing are reported as a non-zero return value.)^
5694 **
5695 ** ^(The BLOB is closed unconditionally. Even if this routine returns
5696 ** an error code, the BLOB is still closed.)^
5697 **
5698 ** ^Calling this routine with a null pointer (such as would be returned
5699 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
5700 */
5701 SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
5702
5703 /*
5704 ** CAPI3REF: Return The Size Of An Open BLOB
5705 **
5706 ** ^Returns the size in bytes of the BLOB accessible via the
5707 ** successfully opened [BLOB handle] in its only argument. ^The
5708 ** incremental blob I/O routines can only read or overwriting existing
5709 ** blob content; they cannot change the size of a blob.
5710 **
5711 ** This routine only works on a [BLOB handle] which has been created
5712 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5713 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5714 ** to this routine results in undefined and probably undesirable behavior.
5715 */
5716 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
5717
5718 /*
5719 ** CAPI3REF: Read Data From A BLOB Incrementally
5720 **
5721 ** ^(This function is used to read data from an open [BLOB handle] into a
5722 ** caller-supplied buffer. N bytes of data are copied into buffer Z
5723 ** from the open BLOB, starting at offset iOffset.)^
5724 **
5725 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5726 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
5727 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
5728 ** ^The size of the blob (and hence the maximum value of N+iOffset)
5729 ** can be determined using the [sqlite3_blob_bytes()] interface.
5730 **
5731 ** ^An attempt to read from an expired [BLOB handle] fails with an
5732 ** error code of [SQLITE_ABORT].
5733 **
5734 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
5735 ** Otherwise, an [error code] or an [extended error code] is returned.)^
5736 **
5737 ** This routine only works on a [BLOB handle] which has been created
5738 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5739 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5740 ** to this routine results in undefined and probably undesirable behavior.
5741 **
5742 ** See also: [sqlite3_blob_write()].
5743 */
5744 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
5745
5746 /*
5747 ** CAPI3REF: Write Data Into A BLOB Incrementally
5748 **
5749 ** ^This function is used to write data into an open [BLOB handle] from a
5750 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
5751 ** into the open BLOB, starting at offset iOffset.
5752 **
5753 ** ^If the [BLOB handle] passed as the first argument was not opened for
5754 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
5755 ** this function returns [SQLITE_READONLY].
5756 **
5757 ** ^This function may only modify the contents of the BLOB; it is
5758 ** not possible to increase the size of a BLOB using this API.
5759 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5760 ** [SQLITE_ERROR] is returned and no data is written. ^If N is
5761 ** less than zero [SQLITE_ERROR] is returned and no data is written.
5762 ** The size of the BLOB (and hence the maximum value of N+iOffset)
5763 ** can be determined using the [sqlite3_blob_bytes()] interface.
5764 **
5765 ** ^An attempt to write to an expired [BLOB handle] fails with an
5766 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
5767 ** before the [BLOB handle] expired are not rolled back by the
5768 ** expiration of the handle, though of course those changes might
5769 ** have been overwritten by the statement that expired the BLOB handle
5770 ** or by other independent statements.
5771 **
5772 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
5773 ** Otherwise, an [error code] or an [extended error code] is returned.)^
5774 **
5775 ** This routine only works on a [BLOB handle] which has been created
5776 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5777 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5778 ** to this routine results in undefined and probably undesirable behavior.
5779 **
5780 ** See also: [sqlite3_blob_read()].
5781 */
5782 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
5783
5784 /*
5785 ** CAPI3REF: Virtual File System Objects
5786 **
5787 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
5788 ** that SQLite uses to interact
5789 ** with the underlying operating system. Most SQLite builds come with a
5790 ** single default VFS that is appropriate for the host computer.
5791 ** New VFSes can be registered and existing VFSes can be unregistered.
5792 ** The following interfaces are provided.
5793 **
5794 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
5795 ** ^Names are case sensitive.
5796 ** ^Names are zero-terminated UTF-8 strings.
5797 ** ^If there is no match, a NULL pointer is returned.
5798 ** ^If zVfsName is NULL then the default VFS is returned.
5799 **
5800 ** ^New VFSes are registered with sqlite3_vfs_register().
5801 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
5802 ** ^The same VFS can be registered multiple times without injury.
5803 ** ^To make an existing VFS into the default VFS, register it again
5804 ** with the makeDflt flag set. If two different VFSes with the
5805 ** same name are registered, the behavior is undefined. If a
5806 ** VFS is registered with a name that is NULL or an empty string,
5807 ** then the behavior is undefined.
5808 **
5809 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
5810 ** ^(If the default VFS is unregistered, another VFS is chosen as
5811 ** the default. The choice for the new VFS is arbitrary.)^
5812 */
5813 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
5814 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
5815 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
5816
5817 /*
5818 ** CAPI3REF: Mutexes
5819 **
5820 ** The SQLite core uses these routines for thread
5821 ** synchronization. Though they are intended for internal
5822 ** use by SQLite, code that links against SQLite is
5823 ** permitted to use any of these routines.
5824 **
5825 ** The SQLite source code contains multiple implementations
5826 ** of these mutex routines. An appropriate implementation
5827 ** is selected automatically at compile-time. ^(The following
5828 ** implementations are available in the SQLite core:
5829 **
5830 ** <ul>
5831 ** <li> SQLITE_MUTEX_PTHREADS
5832 ** <li> SQLITE_MUTEX_W32
5833 ** <li> SQLITE_MUTEX_NOOP
5834 ** </ul>)^
5835 **
5836 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
5837 ** that does no real locking and is appropriate for use in
5838 ** a single-threaded application. ^The SQLITE_MUTEX_PTHREADS and
5839 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
5840 ** and Windows.
5841 **
5842 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
5843 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
5844 ** implementation is included with the library. In this case the
5845 ** application must supply a custom mutex implementation using the
5846 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
5847 ** before calling sqlite3_initialize() or any other public sqlite3_
5848 ** function that calls sqlite3_initialize().)^
5849 **
5850 ** ^The sqlite3_mutex_alloc() routine allocates a new
5851 ** mutex and returns a pointer to it. ^If it returns NULL
5852 ** that means that a mutex could not be allocated. ^SQLite
5853 ** will unwind its stack and return an error. ^(The argument
5854 ** to sqlite3_mutex_alloc() is one of these integer constants:
5855 **
5856 ** <ul>
5857 ** <li> SQLITE_MUTEX_FAST
5858 ** <li> SQLITE_MUTEX_RECURSIVE
5859 ** <li> SQLITE_MUTEX_STATIC_MASTER
5860 ** <li> SQLITE_MUTEX_STATIC_MEM
5861 ** <li> SQLITE_MUTEX_STATIC_MEM2
5862 ** <li> SQLITE_MUTEX_STATIC_PRNG
5863 ** <li> SQLITE_MUTEX_STATIC_LRU
5864 ** <li> SQLITE_MUTEX_STATIC_LRU2
5865 ** </ul>)^
5866 **
5867 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
5868 ** cause sqlite3_mutex_alloc() to create
5869 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
5870 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
5871 ** The mutex implementation does not need to make a distinction
5872 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
5873 ** not want to. ^SQLite will only request a recursive mutex in
5874 ** cases where it really needs one. ^If a faster non-recursive mutex
5875 ** implementation is available on the host platform, the mutex subsystem
5876 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
5877 **
5878 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
5879 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
5880 ** a pointer to a static preexisting mutex. ^Six static mutexes are
5881 ** used by the current version of SQLite. Future versions of SQLite
5882 ** may add additional static mutexes. Static mutexes are for internal
5883 ** use by SQLite only. Applications that use SQLite mutexes should
5884 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
5885 ** SQLITE_MUTEX_RECURSIVE.
5886 **
5887 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
5888 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
5889 ** returns a different mutex on every call. ^But for the static
5890 ** mutex types, the same mutex is returned on every call that has
5891 ** the same type number.
5892 **
5893 ** ^The sqlite3_mutex_free() routine deallocates a previously
5894 ** allocated dynamic mutex. ^SQLite is careful to deallocate every
5895 ** dynamic mutex that it allocates. The dynamic mutexes must not be in
5896 ** use when they are deallocated. Attempting to deallocate a static
5897 ** mutex results in undefined behavior. ^SQLite never deallocates
5898 ** a static mutex.
5899 **
5900 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
5901 ** to enter a mutex. ^If another thread is already within the mutex,
5902 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
5903 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
5904 ** upon successful entry. ^(Mutexes created using
5905 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
5906 ** In such cases the,
5907 ** mutex must be exited an equal number of times before another thread
5908 ** can enter.)^ ^(If the same thread tries to enter any other
5909 ** kind of mutex more than once, the behavior is undefined.
5910 ** SQLite will never exhibit
5911 ** such behavior in its own use of mutexes.)^
5912 **
5913 ** ^(Some systems (for example, Windows 95) do not support the operation
5914 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
5915 ** will always return SQLITE_BUSY. The SQLite core only ever uses
5916 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
5917 **
5918 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
5919 ** previously entered by the same thread. ^(The behavior
5920 ** is undefined if the mutex is not currently entered by the
5921 ** calling thread or is not currently allocated. SQLite will
5922 ** never do either.)^
5923 **
5924 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
5925 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
5926 ** behave as no-ops.
5927 **
5928 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
5929 */
5930 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
5931 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
5932 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
5933 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
5934 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
5935
5936 /*
5937 ** CAPI3REF: Mutex Methods Object
5938 **
5939 ** An instance of this structure defines the low-level routines
5940 ** used to allocate and use mutexes.
5941 **
5942 ** Usually, the default mutex implementations provided by SQLite are
5943 ** sufficient, however the user has the option of substituting a custom
5944 ** implementation for specialized deployments or systems for which SQLite
5945 ** does not provide a suitable implementation. In this case, the user
5946 ** creates and populates an instance of this structure to pass
5947 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
5948 ** Additionally, an instance of this structure can be used as an
5949 ** output variable when querying the system for the current mutex
5950 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
5951 **
5952 ** ^The xMutexInit method defined by this structure is invoked as
5953 ** part of system initialization by the sqlite3_initialize() function.
5954 ** ^The xMutexInit routine is called by SQLite exactly once for each
5955 ** effective call to [sqlite3_initialize()].
5956 **
5957 ** ^The xMutexEnd method defined by this structure is invoked as
5958 ** part of system shutdown by the sqlite3_shutdown() function. The
5959 ** implementation of this method is expected to release all outstanding
5960 ** resources obtained by the mutex methods implementation, especially
5961 ** those obtained by the xMutexInit method. ^The xMutexEnd()
5962 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
5963 **
5964 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
5965 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
5966 ** xMutexNotheld) implement the following interfaces (respectively):
5967 **
5968 ** <ul>
5969 ** <li> [sqlite3_mutex_alloc()] </li>
5970 ** <li> [sqlite3_mutex_free()] </li>
5971 ** <li> [sqlite3_mutex_enter()] </li>
5972 ** <li> [sqlite3_mutex_try()] </li>
5973 ** <li> [sqlite3_mutex_leave()] </li>
5974 ** <li> [sqlite3_mutex_held()] </li>
5975 ** <li> [sqlite3_mutex_notheld()] </li>
5976 ** </ul>)^
5977 **
5978 ** The only difference is that the public sqlite3_XXX functions enumerated
5979 ** above silently ignore any invocations that pass a NULL pointer instead
5980 ** of a valid mutex handle. The implementations of the methods defined
5981 ** by this structure are not required to handle this case, the results
5982 ** of passing a NULL pointer instead of a valid mutex handle are undefined
5983 ** (i.e. it is acceptable to provide an implementation that segfaults if
5984 ** it is passed a NULL pointer).
5985 **
5986 ** The xMutexInit() method must be threadsafe. ^It must be harmless to
5987 ** invoke xMutexInit() multiple times within the same process and without
5988 ** intervening calls to xMutexEnd(). Second and subsequent calls to
5989 ** xMutexInit() must be no-ops.
5990 **
5991 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
5992 ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory
5993 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
5994 ** memory allocation for a fast or recursive mutex.
5995 **
5996 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
5997 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
5998 ** If xMutexInit fails in any way, it is expected to clean up after itself
5999 ** prior to returning.
6000 */
6001 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
6002 struct sqlite3_mutex_methods {
6003 int (*xMutexInit)(void);
6004 int (*xMutexEnd)(void);
6005 sqlite3_mutex *(*xMutexAlloc)(int);
6006 void (*xMutexFree)(sqlite3_mutex *);
6007 void (*xMutexEnter)(sqlite3_mutex *);
6008 int (*xMutexTry)(sqlite3_mutex *);
6009 void (*xMutexLeave)(sqlite3_mutex *);
6010 int (*xMutexHeld)(sqlite3_mutex *);
6011 int (*xMutexNotheld)(sqlite3_mutex *);
6012 };
6013
6014 /*
6015 ** CAPI3REF: Mutex Verification Routines
6016 **
6017 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
6018 ** are intended for use inside assert() statements. ^The SQLite core
6019 ** never uses these routines except inside an assert() and applications
6020 ** are advised to follow the lead of the core. ^The SQLite core only
6021 ** provides implementations for these routines when it is compiled
6022 ** with the SQLITE_DEBUG flag. ^External mutex implementations
6023 ** are only required to provide these routines if SQLITE_DEBUG is
6024 ** defined and if NDEBUG is not defined.
6025 **
6026 ** ^These routines should return true if the mutex in their argument
6027 ** is held or not held, respectively, by the calling thread.
6028 **
6029 ** ^The implementation is not required to provide versions of these
6030 ** routines that actually work. If the implementation does not provide working
6031 ** versions of these routines, it should at least provide stubs that always
6032 ** return true so that one does not get spurious assertion failures.
6033 **
6034 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
6035 ** the routine should return 1. This seems counter-intuitive since
6036 ** clearly the mutex cannot be held if it does not exist. But
6037 ** the reason the mutex does not exist is because the build is not
6038 ** using mutexes. And we do not want the assert() containing the
6039 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
6040 ** the appropriate thing to do. ^The sqlite3_mutex_notheld()
6041 ** interface should also return 1 when given a NULL pointer.
6042 */
6043 #ifndef NDEBUG
6044 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
6045 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
6046 #endif
6047
6048 /*
6049 ** CAPI3REF: Mutex Types
6050 **
6051 ** The [sqlite3_mutex_alloc()] interface takes a single argument
6052 ** which is one of these integer constants.
6053 **
6054 ** The set of static mutexes may change from one SQLite release to the
6055 ** next. Applications that override the built-in mutex logic must be
6056 ** prepared to accommodate additional static mutexes.
6057 */
6058 #define SQLITE_MUTEX_FAST 0
6059 #define SQLITE_MUTEX_RECURSIVE 1
6060 #define SQLITE_MUTEX_STATIC_MASTER 2
6061 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
6062 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
6063 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
6064 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */
6065 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
6066 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
6067 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
6068
6069 /*
6070 ** CAPI3REF: Retrieve the mutex for a database connection
6071 **
6072 ** ^This interface returns a pointer the [sqlite3_mutex] object that
6073 ** serializes access to the [database connection] given in the argument
6074 ** when the [threading mode] is Serialized.
6075 ** ^If the [threading mode] is Single-thread or Multi-thread then this
6076 ** routine returns a NULL pointer.
6077 */
6078 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
6079
6080 /*
6081 ** CAPI3REF: Low-Level Control Of Database Files
6082 **
6083 ** ^The [sqlite3_file_control()] interface makes a direct call to the
6084 ** xFileControl method for the [sqlite3_io_methods] object associated
6085 ** with a particular database identified by the second argument. ^The
6086 ** name of the database is "main" for the main database or "temp" for the
6087 ** TEMP database, or the name that appears after the AS keyword for
6088 ** databases that are added using the [ATTACH] SQL command.
6089 ** ^A NULL pointer can be used in place of "main" to refer to the
6090 ** main database file.
6091 ** ^The third and fourth parameters to this routine
6092 ** are passed directly through to the second and third parameters of
6093 ** the xFileControl method. ^The return value of the xFileControl
6094 ** method becomes the return value of this routine.
6095 **
6096 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
6097 ** a pointer to the underlying [sqlite3_file] object to be written into
6098 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER
6099 ** case is a short-circuit path which does not actually invoke the
6100 ** underlying sqlite3_io_methods.xFileControl method.
6101 **
6102 ** ^If the second parameter (zDbName) does not match the name of any
6103 ** open database file, then SQLITE_ERROR is returned. ^This error
6104 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
6105 ** or [sqlite3_errmsg()]. The underlying xFileControl method might
6106 ** also return SQLITE_ERROR. There is no way to distinguish between
6107 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
6108 ** xFileControl method.
6109 **
6110 ** See also: [SQLITE_FCNTL_LOCKSTATE]
6111 */
6112 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
6113
6114 /*
6115 ** CAPI3REF: Testing Interface
6116 **
6117 ** ^The sqlite3_test_control() interface is used to read out internal
6118 ** state of SQLite and to inject faults into SQLite for testing
6119 ** purposes. ^The first parameter is an operation code that determines
6120 ** the number, meaning, and operation of all subsequent parameters.
6121 **
6122 ** This interface is not for use by applications. It exists solely
6123 ** for verifying the correct operation of the SQLite library. Depending
6124 ** on how the SQLite library is compiled, this interface might not exist.
6125 **
6126 ** The details of the operation codes, their meanings, the parameters
6127 ** they take, and what they do are all subject to change without notice.
6128 ** Unlike most of the SQLite API, this function is not guaranteed to
6129 ** operate consistently from one release to the next.
6130 */
6131 SQLITE_API int sqlite3_test_control(int op, ...);
6132
6133 /*
6134 ** CAPI3REF: Testing Interface Operation Codes
6135 **
6136 ** These constants are the valid operation code parameters used
6137 ** as the first argument to [sqlite3_test_control()].
6138 **
6139 ** These parameters and their meanings are subject to change
6140 ** without notice. These values are for testing purposes only.
6141 ** Applications should not use any of these parameters or the
6142 ** [sqlite3_test_control()] interface.
6143 */
6144 #define SQLITE_TESTCTRL_FIRST 5
6145 #define SQLITE_TESTCTRL_PRNG_SAVE 5
6146 #define SQLITE_TESTCTRL_PRNG_RESTORE 6
6147 #define SQLITE_TESTCTRL_PRNG_RESET 7
6148 #define SQLITE_TESTCTRL_BITVEC_TEST 8
6149 #define SQLITE_TESTCTRL_FAULT_INSTALL 9
6150 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
6151 #define SQLITE_TESTCTRL_PENDING_BYTE 11
6152 #define SQLITE_TESTCTRL_ASSERT 12
6153 #define SQLITE_TESTCTRL_ALWAYS 13
6154 #define SQLITE_TESTCTRL_RESERVE 14
6155 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
6156 #define SQLITE_TESTCTRL_ISKEYWORD 16
6157 #define SQLITE_TESTCTRL_SCRATCHMALLOC 17
6158 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
6159 #define SQLITE_TESTCTRL_EXPLAIN_STMT 19
6160 #define SQLITE_TESTCTRL_NEVER_CORRUPT 20
6161 #define SQLITE_TESTCTRL_VDBE_COVERAGE 21
6162 #define SQLITE_TESTCTRL_BYTEORDER 22
6163 #define SQLITE_TESTCTRL_LAST 22
6164
6165 /*
6166 ** CAPI3REF: SQLite Runtime Status
6167 **
6168 ** ^This interface is used to retrieve runtime status information
6169 ** about the performance of SQLite, and optionally to reset various
6170 ** highwater marks. ^The first argument is an integer code for
6171 ** the specific parameter to measure. ^(Recognized integer codes
6172 ** are of the form [status parameters | SQLITE_STATUS_...].)^
6173 ** ^The current value of the parameter is returned into *pCurrent.
6174 ** ^The highest recorded value is returned in *pHighwater. ^If the
6175 ** resetFlag is true, then the highest record value is reset after
6176 ** *pHighwater is written. ^(Some parameters do not record the highest
6177 ** value. For those parameters
6178 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
6179 ** ^(Other parameters record only the highwater mark and not the current
6180 ** value. For these latter parameters nothing is written into *pCurrent.)^
6181 **
6182 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a
6183 ** non-zero [error code] on failure.
6184 **
6185 ** This routine is threadsafe but is not atomic. This routine can be
6186 ** called while other threads are running the same or different SQLite
6187 ** interfaces. However the values returned in *pCurrent and
6188 ** *pHighwater reflect the status of SQLite at different points in time
6189 ** and it is possible that another thread might change the parameter
6190 ** in between the times when *pCurrent and *pHighwater are written.
6191 **
6192 ** See also: [sqlite3_db_status()]
6193 */
6194 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
6195
6196
6197 /*
6198 ** CAPI3REF: Status Parameters
6199 ** KEYWORDS: {status parameters}
6200 **
6201 ** These integer constants designate various run-time status parameters
6202 ** that can be returned by [sqlite3_status()].
6203 **
6204 ** <dl>
6205 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
6206 ** <dd>This parameter is the current amount of memory checked out
6207 ** using [sqlite3_malloc()], either directly or indirectly. The
6208 ** figure includes calls made to [sqlite3_malloc()] by the application
6209 ** and internal memory usage by the SQLite library. Scratch memory
6210 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
6211 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
6212 ** this parameter. The amount returned is the sum of the allocation
6213 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
6214 **
6215 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
6216 ** <dd>This parameter records the largest memory allocation request
6217 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
6218 ** internal equivalents). Only the value returned in the
6219 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6220 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6221 **
6222 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
6223 ** <dd>This parameter records the number of separate memory allocations
6224 ** currently checked out.</dd>)^
6225 **
6226 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
6227 ** <dd>This parameter returns the number of pages used out of the
6228 ** [pagecache memory allocator] that was configured using
6229 ** [SQLITE_CONFIG_PAGECACHE]. The
6230 ** value returned is in pages, not in bytes.</dd>)^
6231 **
6232 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
6233 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
6234 ** <dd>This parameter returns the number of bytes of page cache
6235 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
6236 ** buffer and where forced to overflow to [sqlite3_malloc()]. The
6237 ** returned value includes allocations that overflowed because they
6238 ** where too large (they were larger than the "sz" parameter to
6239 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
6240 ** no space was left in the page cache.</dd>)^
6241 **
6242 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
6243 ** <dd>This parameter records the largest memory allocation request
6244 ** handed to [pagecache memory allocator]. Only the value returned in the
6245 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6246 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6247 **
6248 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
6249 ** <dd>This parameter returns the number of allocations used out of the
6250 ** [scratch memory allocator] configured using
6251 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not
6252 ** in bytes. Since a single thread may only have one scratch allocation
6253 ** outstanding at time, this parameter also reports the number of threads
6254 ** using scratch memory at the same time.</dd>)^
6255 **
6256 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
6257 ** <dd>This parameter returns the number of bytes of scratch memory
6258 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
6259 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values
6260 ** returned include overflows because the requested allocation was too
6261 ** larger (that is, because the requested allocation was larger than the
6262 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
6263 ** slots were available.
6264 ** </dd>)^
6265 **
6266 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
6267 ** <dd>This parameter records the largest memory allocation request
6268 ** handed to [scratch memory allocator]. Only the value returned in the
6269 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6270 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6271 **
6272 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
6273 ** <dd>This parameter records the deepest parser stack. It is only
6274 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
6275 ** </dl>
6276 **
6277 ** New status parameters may be added from time to time.
6278 */
6279 #define SQLITE_STATUS_MEMORY_USED 0
6280 #define SQLITE_STATUS_PAGECACHE_USED 1
6281 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
6282 #define SQLITE_STATUS_SCRATCH_USED 3
6283 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4
6284 #define SQLITE_STATUS_MALLOC_SIZE 5
6285 #define SQLITE_STATUS_PARSER_STACK 6
6286 #define SQLITE_STATUS_PAGECACHE_SIZE 7
6287 #define SQLITE_STATUS_SCRATCH_SIZE 8
6288 #define SQLITE_STATUS_MALLOC_COUNT 9
6289
6290 /*
6291 ** CAPI3REF: Database Connection Status
6292 **
6293 ** ^This interface is used to retrieve runtime status information
6294 ** about a single [database connection]. ^The first argument is the
6295 ** database connection object to be interrogated. ^The second argument
6296 ** is an integer constant, taken from the set of
6297 ** [SQLITE_DBSTATUS options], that
6298 ** determines the parameter to interrogate. The set of
6299 ** [SQLITE_DBSTATUS options] is likely
6300 ** to grow in future releases of SQLite.
6301 **
6302 ** ^The current value of the requested parameter is written into *pCur
6303 ** and the highest instantaneous value is written into *pHiwtr. ^If
6304 ** the resetFlg is true, then the highest instantaneous value is
6305 ** reset back down to the current value.
6306 **
6307 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
6308 ** non-zero [error code] on failure.
6309 **
6310 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
6311 */
6312 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
6313
6314 /*
6315 ** CAPI3REF: Status Parameters for database connections
6316 ** KEYWORDS: {SQLITE_DBSTATUS options}
6317 **
6318 ** These constants are the available integer "verbs" that can be passed as
6319 ** the second argument to the [sqlite3_db_status()] interface.
6320 **
6321 ** New verbs may be added in future releases of SQLite. Existing verbs
6322 ** might be discontinued. Applications should check the return code from
6323 ** [sqlite3_db_status()] to make sure that the call worked.
6324 ** The [sqlite3_db_status()] interface will return a non-zero error code
6325 ** if a discontinued or unsupported verb is invoked.
6326 **
6327 ** <dl>
6328 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
6329 ** <dd>This parameter returns the number of lookaside memory slots currently
6330 ** checked out.</dd>)^
6331 **
6332 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
6333 ** <dd>This parameter returns the number malloc attempts that were
6334 ** satisfied using lookaside memory. Only the high-water value is meaningful;
6335 ** the current value is always zero.)^
6336 **
6337 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
6338 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
6339 ** <dd>This parameter returns the number malloc attempts that might have
6340 ** been satisfied using lookaside memory but failed due to the amount of
6341 ** memory requested being larger than the lookaside slot size.
6342 ** Only the high-water value is meaningful;
6343 ** the current value is always zero.)^
6344 **
6345 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
6346 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
6347 ** <dd>This parameter returns the number malloc attempts that might have
6348 ** been satisfied using lookaside memory but failed due to all lookaside
6349 ** memory already being in use.
6350 ** Only the high-water value is meaningful;
6351 ** the current value is always zero.)^
6352 **
6353 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
6354 ** <dd>This parameter returns the approximate number of of bytes of heap
6355 ** memory used by all pager caches associated with the database connection.)^
6356 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
6357 **
6358 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
6359 ** <dd>This parameter returns the approximate number of of bytes of heap
6360 ** memory used to store the schema for all databases associated
6361 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
6362 ** ^The full amount of memory used by the schemas is reported, even if the
6363 ** schema memory is shared with other database connections due to
6364 ** [shared cache mode] being enabled.
6365 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
6366 **
6367 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
6368 ** <dd>This parameter returns the approximate number of of bytes of heap
6369 ** and lookaside memory used by all prepared statements associated with
6370 ** the database connection.)^
6371 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
6372 ** </dd>
6373 **
6374 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
6375 ** <dd>This parameter returns the number of pager cache hits that have
6376 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
6377 ** is always 0.
6378 ** </dd>
6379 **
6380 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
6381 ** <dd>This parameter returns the number of pager cache misses that have
6382 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
6383 ** is always 0.
6384 ** </dd>
6385 **
6386 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
6387 ** <dd>This parameter returns the number of dirty cache entries that have
6388 ** been written to disk. Specifically, the number of pages written to the
6389 ** wal file in wal mode databases, or the number of pages written to the
6390 ** database file in rollback mode databases. Any pages written as part of
6391 ** transaction rollback or database recovery operations are not included.
6392 ** If an IO or other error occurs while writing a page to disk, the effect
6393 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
6394 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
6395 ** </dd>
6396 **
6397 ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
6398 ** <dd>This parameter returns zero for the current value if and only if
6399 ** all foreign key constraints (deferred or immediate) have been
6400 ** resolved.)^ ^The highwater mark is always 0.
6401 ** </dd>
6402 ** </dl>
6403 */
6404 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
6405 #define SQLITE_DBSTATUS_CACHE_USED 1
6406 #define SQLITE_DBSTATUS_SCHEMA_USED 2
6407 #define SQLITE_DBSTATUS_STMT_USED 3
6408 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
6409 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
6410 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
6411 #define SQLITE_DBSTATUS_CACHE_HIT 7
6412 #define SQLITE_DBSTATUS_CACHE_MISS 8
6413 #define SQLITE_DBSTATUS_CACHE_WRITE 9
6414 #define SQLITE_DBSTATUS_DEFERRED_FKS 10
6415 #define SQLITE_DBSTATUS_MAX 10 /* Largest defined DBSTATUS */
6416
6417
6418 /*
6419 ** CAPI3REF: Prepared Statement Status
6420 **
6421 ** ^(Each prepared statement maintains various
6422 ** [SQLITE_STMTSTATUS counters] that measure the number
6423 ** of times it has performed specific operations.)^ These counters can
6424 ** be used to monitor the performance characteristics of the prepared
6425 ** statements. For example, if the number of table steps greatly exceeds
6426 ** the number of table searches or result rows, that would tend to indicate
6427 ** that the prepared statement is using a full table scan rather than
6428 ** an index.
6429 **
6430 ** ^(This interface is used to retrieve and reset counter values from
6431 ** a [prepared statement]. The first argument is the prepared statement
6432 ** object to be interrogated. The second argument
6433 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
6434 ** to be interrogated.)^
6435 ** ^The current value of the requested counter is returned.
6436 ** ^If the resetFlg is true, then the counter is reset to zero after this
6437 ** interface call returns.
6438 **
6439 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
6440 */
6441 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
6442
6443 /*
6444 ** CAPI3REF: Status Parameters for prepared statements
6445 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
6446 **
6447 ** These preprocessor macros define integer codes that name counter
6448 ** values associated with the [sqlite3_stmt_status()] interface.
6449 ** The meanings of the various counters are as follows:
6450 **
6451 ** <dl>
6452 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
6453 ** <dd>^This is the number of times that SQLite has stepped forward in
6454 ** a table as part of a full table scan. Large numbers for this counter
6455 ** may indicate opportunities for performance improvement through
6456 ** careful use of indices.</dd>
6457 **
6458 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
6459 ** <dd>^This is the number of sort operations that have occurred.
6460 ** A non-zero value in this counter may indicate an opportunity to
6461 ** improvement performance through careful use of indices.</dd>
6462 **
6463 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
6464 ** <dd>^This is the number of rows inserted into transient indices that
6465 ** were created automatically in order to help joins run faster.
6466 ** A non-zero value in this counter may indicate an opportunity to
6467 ** improvement performance by adding permanent indices that do not
6468 ** need to be reinitialized each time the statement is run.</dd>
6469 **
6470 ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
6471 ** <dd>^This is the number of virtual machine operations executed
6472 ** by the prepared statement if that number is less than or equal
6473 ** to 2147483647. The number of virtual machine operations can be
6474 ** used as a proxy for the total work done by the prepared statement.
6475 ** If the number of virtual machine operations exceeds 2147483647
6476 ** then the value returned by this statement status code is undefined.
6477 ** </dd>
6478 ** </dl>
6479 */
6480 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
6481 #define SQLITE_STMTSTATUS_SORT 2
6482 #define SQLITE_STMTSTATUS_AUTOINDEX 3
6483 #define SQLITE_STMTSTATUS_VM_STEP 4
6484
6485 /*
6486 ** CAPI3REF: Custom Page Cache Object
6487 **
6488 ** The sqlite3_pcache type is opaque. It is implemented by
6489 ** the pluggable module. The SQLite core has no knowledge of
6490 ** its size or internal structure and never deals with the
6491 ** sqlite3_pcache object except by holding and passing pointers
6492 ** to the object.
6493 **
6494 ** See [sqlite3_pcache_methods2] for additional information.
6495 */
6496 typedef struct sqlite3_pcache sqlite3_pcache;
6497
6498 /*
6499 ** CAPI3REF: Custom Page Cache Object
6500 **
6501 ** The sqlite3_pcache_page object represents a single page in the
6502 ** page cache. The page cache will allocate instances of this
6503 ** object. Various methods of the page cache use pointers to instances
6504 ** of this object as parameters or as their return value.
6505 **
6506 ** See [sqlite3_pcache_methods2] for additional information.
6507 */
6508 typedef struct sqlite3_pcache_page sqlite3_pcache_page;
6509 struct sqlite3_pcache_page {
6510 void *pBuf; /* The content of the page */
6511 void *pExtra; /* Extra information associated with the page */
6512 };
6513
6514 /*
6515 ** CAPI3REF: Application Defined Page Cache.
6516 ** KEYWORDS: {page cache}
6517 **
6518 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
6519 ** register an alternative page cache implementation by passing in an
6520 ** instance of the sqlite3_pcache_methods2 structure.)^
6521 ** In many applications, most of the heap memory allocated by
6522 ** SQLite is used for the page cache.
6523 ** By implementing a
6524 ** custom page cache using this API, an application can better control
6525 ** the amount of memory consumed by SQLite, the way in which
6526 ** that memory is allocated and released, and the policies used to
6527 ** determine exactly which parts of a database file are cached and for
6528 ** how long.
6529 **
6530 ** The alternative page cache mechanism is an
6531 ** extreme measure that is only needed by the most demanding applications.
6532 ** The built-in page cache is recommended for most uses.
6533 **
6534 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
6535 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
6536 ** the application may discard the parameter after the call to
6537 ** [sqlite3_config()] returns.)^
6538 **
6539 ** [[the xInit() page cache method]]
6540 ** ^(The xInit() method is called once for each effective
6541 ** call to [sqlite3_initialize()])^
6542 ** (usually only once during the lifetime of the process). ^(The xInit()
6543 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
6544 ** The intent of the xInit() method is to set up global data structures
6545 ** required by the custom page cache implementation.
6546 ** ^(If the xInit() method is NULL, then the
6547 ** built-in default page cache is used instead of the application defined
6548 ** page cache.)^
6549 **
6550 ** [[the xShutdown() page cache method]]
6551 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
6552 ** It can be used to clean up
6553 ** any outstanding resources before process shutdown, if required.
6554 ** ^The xShutdown() method may be NULL.
6555 **
6556 ** ^SQLite automatically serializes calls to the xInit method,
6557 ** so the xInit method need not be threadsafe. ^The
6558 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
6559 ** not need to be threadsafe either. All other methods must be threadsafe
6560 ** in multithreaded applications.
6561 **
6562 ** ^SQLite will never invoke xInit() more than once without an intervening
6563 ** call to xShutdown().
6564 **
6565 ** [[the xCreate() page cache methods]]
6566 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
6567 ** SQLite will typically create one cache instance for each open database file,
6568 ** though this is not guaranteed. ^The
6569 ** first parameter, szPage, is the size in bytes of the pages that must
6570 ** be allocated by the cache. ^szPage will always a power of two. ^The
6571 ** second parameter szExtra is a number of bytes of extra storage
6572 ** associated with each page cache entry. ^The szExtra parameter will
6573 ** a number less than 250. SQLite will use the
6574 ** extra szExtra bytes on each page to store metadata about the underlying
6575 ** database page on disk. The value passed into szExtra depends
6576 ** on the SQLite version, the target platform, and how SQLite was compiled.
6577 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
6578 ** created will be used to cache database pages of a file stored on disk, or
6579 ** false if it is used for an in-memory database. The cache implementation
6580 ** does not have to do anything special based with the value of bPurgeable;
6581 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
6582 ** never invoke xUnpin() except to deliberately delete a page.
6583 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
6584 ** false will always have the "discard" flag set to true.
6585 ** ^Hence, a cache created with bPurgeable false will
6586 ** never contain any unpinned pages.
6587 **
6588 ** [[the xCachesize() page cache method]]
6589 ** ^(The xCachesize() method may be called at any time by SQLite to set the
6590 ** suggested maximum cache-size (number of pages stored by) the cache
6591 ** instance passed as the first argument. This is the value configured using
6592 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
6593 ** parameter, the implementation is not required to do anything with this
6594 ** value; it is advisory only.
6595 **
6596 ** [[the xPagecount() page cache methods]]
6597 ** The xPagecount() method must return the number of pages currently
6598 ** stored in the cache, both pinned and unpinned.
6599 **
6600 ** [[the xFetch() page cache methods]]
6601 ** The xFetch() method locates a page in the cache and returns a pointer to
6602 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
6603 ** The pBuf element of the returned sqlite3_pcache_page object will be a
6604 ** pointer to a buffer of szPage bytes used to store the content of a
6605 ** single database page. The pExtra element of sqlite3_pcache_page will be
6606 ** a pointer to the szExtra bytes of extra storage that SQLite has requested
6607 ** for each entry in the page cache.
6608 **
6609 ** The page to be fetched is determined by the key. ^The minimum key value
6610 ** is 1. After it has been retrieved using xFetch, the page is considered
6611 ** to be "pinned".
6612 **
6613 ** If the requested page is already in the page cache, then the page cache
6614 ** implementation must return a pointer to the page buffer with its content
6615 ** intact. If the requested page is not already in the cache, then the
6616 ** cache implementation should use the value of the createFlag
6617 ** parameter to help it determined what action to take:
6618 **
6619 ** <table border=1 width=85% align=center>
6620 ** <tr><th> createFlag <th> Behavior when page is not already in cache
6621 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
6622 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
6623 ** Otherwise return NULL.
6624 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
6625 ** NULL if allocating a new page is effectively impossible.
6626 ** </table>
6627 **
6628 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
6629 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
6630 ** failed.)^ In between the to xFetch() calls, SQLite may
6631 ** attempt to unpin one or more cache pages by spilling the content of
6632 ** pinned pages to disk and synching the operating system disk cache.
6633 **
6634 ** [[the xUnpin() page cache method]]
6635 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
6636 ** as its second argument. If the third parameter, discard, is non-zero,
6637 ** then the page must be evicted from the cache.
6638 ** ^If the discard parameter is
6639 ** zero, then the page may be discarded or retained at the discretion of
6640 ** page cache implementation. ^The page cache implementation
6641 ** may choose to evict unpinned pages at any time.
6642 **
6643 ** The cache must not perform any reference counting. A single
6644 ** call to xUnpin() unpins the page regardless of the number of prior calls
6645 ** to xFetch().
6646 **
6647 ** [[the xRekey() page cache methods]]
6648 ** The xRekey() method is used to change the key value associated with the
6649 ** page passed as the second argument. If the cache
6650 ** previously contains an entry associated with newKey, it must be
6651 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
6652 ** to be pinned.
6653 **
6654 ** When SQLite calls the xTruncate() method, the cache must discard all
6655 ** existing cache entries with page numbers (keys) greater than or equal
6656 ** to the value of the iLimit parameter passed to xTruncate(). If any
6657 ** of these pages are pinned, they are implicitly unpinned, meaning that
6658 ** they can be safely discarded.
6659 **
6660 ** [[the xDestroy() page cache method]]
6661 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
6662 ** All resources associated with the specified cache should be freed. ^After
6663 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
6664 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
6665 ** functions.
6666 **
6667 ** [[the xShrink() page cache method]]
6668 ** ^SQLite invokes the xShrink() method when it wants the page cache to
6669 ** free up as much of heap memory as possible. The page cache implementation
6670 ** is not obligated to free any memory, but well-behaved implementations should
6671 ** do their best.
6672 */
6673 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
6674 struct sqlite3_pcache_methods2 {
6675 int iVersion;
6676 void *pArg;
6677 int (*xInit)(void*);
6678 void (*xShutdown)(void*);
6679 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
6680 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6681 int (*xPagecount)(sqlite3_pcache*);
6682 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6683 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
6684 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
6685 unsigned oldKey, unsigned newKey);
6686 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6687 void (*xDestroy)(sqlite3_pcache*);
6688 void (*xShrink)(sqlite3_pcache*);
6689 };
6690
6691 /*
6692 ** This is the obsolete pcache_methods object that has now been replaced
6693 ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
6694 ** retained in the header file for backwards compatibility only.
6695 */
6696 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
6697 struct sqlite3_pcache_methods {
6698 void *pArg;
6699 int (*xInit)(void*);
6700 void (*xShutdown)(void*);
6701 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
6702 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6703 int (*xPagecount)(sqlite3_pcache*);
6704 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6705 void (*xUnpin)(sqlite3_pcache*, void*, int discard);
6706 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
6707 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6708 void (*xDestroy)(sqlite3_pcache*);
6709 };
6710
6711
6712 /*
6713 ** CAPI3REF: Online Backup Object
6714 **
6715 ** The sqlite3_backup object records state information about an ongoing
6716 ** online backup operation. ^The sqlite3_backup object is created by
6717 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
6718 ** [sqlite3_backup_finish()].
6719 **
6720 ** See Also: [Using the SQLite Online Backup API]
6721 */
6722 typedef struct sqlite3_backup sqlite3_backup;
6723
6724 /*
6725 ** CAPI3REF: Online Backup API.
6726 **
6727 ** The backup API copies the content of one database into another.
6728 ** It is useful either for creating backups of databases or
6729 ** for copying in-memory databases to or from persistent files.
6730 **
6731 ** See Also: [Using the SQLite Online Backup API]
6732 **
6733 ** ^SQLite holds a write transaction open on the destination database file
6734 ** for the duration of the backup operation.
6735 ** ^The source database is read-locked only while it is being read;
6736 ** it is not locked continuously for the entire backup operation.
6737 ** ^Thus, the backup may be performed on a live source database without
6738 ** preventing other database connections from
6739 ** reading or writing to the source database while the backup is underway.
6740 **
6741 ** ^(To perform a backup operation:
6742 ** <ol>
6743 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
6744 ** backup,
6745 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
6746 ** the data between the two databases, and finally
6747 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
6748 ** associated with the backup operation.
6749 ** </ol>)^
6750 ** There should be exactly one call to sqlite3_backup_finish() for each
6751 ** successful call to sqlite3_backup_init().
6752 **
6753 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
6754 **
6755 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
6756 ** [database connection] associated with the destination database
6757 ** and the database name, respectively.
6758 ** ^The database name is "main" for the main database, "temp" for the
6759 ** temporary database, or the name specified after the AS keyword in
6760 ** an [ATTACH] statement for an attached database.
6761 ** ^The S and M arguments passed to
6762 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
6763 ** and database name of the source database, respectively.
6764 ** ^The source and destination [database connections] (parameters S and D)
6765 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
6766 ** an error.
6767 **
6768 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
6769 ** returned and an error code and error message are stored in the
6770 ** destination [database connection] D.
6771 ** ^The error code and message for the failed call to sqlite3_backup_init()
6772 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
6773 ** [sqlite3_errmsg16()] functions.
6774 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
6775 ** [sqlite3_backup] object.
6776 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
6777 ** sqlite3_backup_finish() functions to perform the specified backup
6778 ** operation.
6779 **
6780 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
6781 **
6782 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
6783 ** the source and destination databases specified by [sqlite3_backup] object B.
6784 ** ^If N is negative, all remaining source pages are copied.
6785 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
6786 ** are still more pages to be copied, then the function returns [SQLITE_OK].
6787 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
6788 ** from source to destination, then it returns [SQLITE_DONE].
6789 ** ^If an error occurs while running sqlite3_backup_step(B,N),
6790 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
6791 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
6792 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
6793 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
6794 **
6795 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
6796 ** <ol>
6797 ** <li> the destination database was opened read-only, or
6798 ** <li> the destination database is using write-ahead-log journaling
6799 ** and the destination and source page sizes differ, or
6800 ** <li> the destination database is an in-memory database and the
6801 ** destination and source page sizes differ.
6802 ** </ol>)^
6803 **
6804 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
6805 ** the [sqlite3_busy_handler | busy-handler function]
6806 ** is invoked (if one is specified). ^If the
6807 ** busy-handler returns non-zero before the lock is available, then
6808 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
6809 ** sqlite3_backup_step() can be retried later. ^If the source
6810 ** [database connection]
6811 ** is being used to write to the source database when sqlite3_backup_step()
6812 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
6813 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
6814 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
6815 ** [SQLITE_READONLY] is returned, then
6816 ** there is no point in retrying the call to sqlite3_backup_step(). These
6817 ** errors are considered fatal.)^ The application must accept
6818 ** that the backup operation has failed and pass the backup operation handle
6819 ** to the sqlite3_backup_finish() to release associated resources.
6820 **
6821 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
6822 ** on the destination file. ^The exclusive lock is not released until either
6823 ** sqlite3_backup_finish() is called or the backup operation is complete
6824 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
6825 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
6826 ** lasts for the duration of the sqlite3_backup_step() call.
6827 ** ^Because the source database is not locked between calls to
6828 ** sqlite3_backup_step(), the source database may be modified mid-way
6829 ** through the backup process. ^If the source database is modified by an
6830 ** external process or via a database connection other than the one being
6831 ** used by the backup operation, then the backup will be automatically
6832 ** restarted by the next call to sqlite3_backup_step(). ^If the source
6833 ** database is modified by the using the same database connection as is used
6834 ** by the backup operation, then the backup database is automatically
6835 ** updated at the same time.
6836 **
6837 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
6838 **
6839 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
6840 ** application wishes to abandon the backup operation, the application
6841 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
6842 ** ^The sqlite3_backup_finish() interfaces releases all
6843 ** resources associated with the [sqlite3_backup] object.
6844 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
6845 ** active write-transaction on the destination database is rolled back.
6846 ** The [sqlite3_backup] object is invalid
6847 ** and may not be used following a call to sqlite3_backup_finish().
6848 **
6849 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
6850 ** sqlite3_backup_step() errors occurred, regardless or whether or not
6851 ** sqlite3_backup_step() completed.
6852 ** ^If an out-of-memory condition or IO error occurred during any prior
6853 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
6854 ** sqlite3_backup_finish() returns the corresponding [error code].
6855 **
6856 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
6857 ** is not a permanent error and does not affect the return value of
6858 ** sqlite3_backup_finish().
6859 **
6860 ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]
6861 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
6862 **
6863 ** ^Each call to sqlite3_backup_step() sets two values inside
6864 ** the [sqlite3_backup] object: the number of pages still to be backed
6865 ** up and the total number of pages in the source database file.
6866 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
6867 ** retrieve these two values, respectively.
6868 **
6869 ** ^The values returned by these functions are only updated by
6870 ** sqlite3_backup_step(). ^If the source database is modified during a backup
6871 ** operation, then the values are not updated to account for any extra
6872 ** pages that need to be updated or the size of the source database file
6873 ** changing.
6874 **
6875 ** <b>Concurrent Usage of Database Handles</b>
6876 **
6877 ** ^The source [database connection] may be used by the application for other
6878 ** purposes while a backup operation is underway or being initialized.
6879 ** ^If SQLite is compiled and configured to support threadsafe database
6880 ** connections, then the source database connection may be used concurrently
6881 ** from within other threads.
6882 **
6883 ** However, the application must guarantee that the destination
6884 ** [database connection] is not passed to any other API (by any thread) after
6885 ** sqlite3_backup_init() is called and before the corresponding call to
6886 ** sqlite3_backup_finish(). SQLite does not currently check to see
6887 ** if the application incorrectly accesses the destination [database connection]
6888 ** and so no error code is reported, but the operations may malfunction
6889 ** nevertheless. Use of the destination database connection while a
6890 ** backup is in progress might also also cause a mutex deadlock.
6891 **
6892 ** If running in [shared cache mode], the application must
6893 ** guarantee that the shared cache used by the destination database
6894 ** is not accessed while the backup is running. In practice this means
6895 ** that the application must guarantee that the disk file being
6896 ** backed up to is not accessed by any connection within the process,
6897 ** not just the specific connection that was passed to sqlite3_backup_init().
6898 **
6899 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
6900 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
6901 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
6902 ** APIs are not strictly speaking threadsafe. If they are invoked at the
6903 ** same time as another thread is invoking sqlite3_backup_step() it is
6904 ** possible that they return invalid values.
6905 */
6906 SQLITE_API sqlite3_backup *sqlite3_backup_init(
6907 sqlite3 *pDest, /* Destination database handle */
6908 const char *zDestName, /* Destination database name */
6909 sqlite3 *pSource, /* Source database handle */
6910 const char *zSourceName /* Source database name */
6911 );
6912 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
6913 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
6914 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
6915 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
6916
6917 /*
6918 ** CAPI3REF: Unlock Notification
6919 **
6920 ** ^When running in shared-cache mode, a database operation may fail with
6921 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
6922 ** individual tables within the shared-cache cannot be obtained. See
6923 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
6924 ** ^This API may be used to register a callback that SQLite will invoke
6925 ** when the connection currently holding the required lock relinquishes it.
6926 ** ^This API is only available if the library was compiled with the
6927 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
6928 **
6929 ** See Also: [Using the SQLite Unlock Notification Feature].
6930 **
6931 ** ^Shared-cache locks are released when a database connection concludes
6932 ** its current transaction, either by committing it or rolling it back.
6933 **
6934 ** ^When a connection (known as the blocked connection) fails to obtain a
6935 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
6936 ** identity of the database connection (the blocking connection) that
6937 ** has locked the required resource is stored internally. ^After an
6938 ** application receives an SQLITE_LOCKED error, it may call the
6939 ** sqlite3_unlock_notify() method with the blocked connection handle as
6940 ** the first argument to register for a callback that will be invoked
6941 ** when the blocking connections current transaction is concluded. ^The
6942 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
6943 ** call that concludes the blocking connections transaction.
6944 **
6945 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
6946 ** there is a chance that the blocking connection will have already
6947 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
6948 ** If this happens, then the specified callback is invoked immediately,
6949 ** from within the call to sqlite3_unlock_notify().)^
6950 **
6951 ** ^If the blocked connection is attempting to obtain a write-lock on a
6952 ** shared-cache table, and more than one other connection currently holds
6953 ** a read-lock on the same table, then SQLite arbitrarily selects one of
6954 ** the other connections to use as the blocking connection.
6955 **
6956 ** ^(There may be at most one unlock-notify callback registered by a
6957 ** blocked connection. If sqlite3_unlock_notify() is called when the
6958 ** blocked connection already has a registered unlock-notify callback,
6959 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
6960 ** called with a NULL pointer as its second argument, then any existing
6961 ** unlock-notify callback is canceled. ^The blocked connections
6962 ** unlock-notify callback may also be canceled by closing the blocked
6963 ** connection using [sqlite3_close()].
6964 **
6965 ** The unlock-notify callback is not reentrant. If an application invokes
6966 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
6967 ** crash or deadlock may be the result.
6968 **
6969 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
6970 ** returns SQLITE_OK.
6971 **
6972 ** <b>Callback Invocation Details</b>
6973 **
6974 ** When an unlock-notify callback is registered, the application provides a
6975 ** single void* pointer that is passed to the callback when it is invoked.
6976 ** However, the signature of the callback function allows SQLite to pass
6977 ** it an array of void* context pointers. The first argument passed to
6978 ** an unlock-notify callback is a pointer to an array of void* pointers,
6979 ** and the second is the number of entries in the array.
6980 **
6981 ** When a blocking connections transaction is concluded, there may be
6982 ** more than one blocked connection that has registered for an unlock-notify
6983 ** callback. ^If two or more such blocked connections have specified the
6984 ** same callback function, then instead of invoking the callback function
6985 ** multiple times, it is invoked once with the set of void* context pointers
6986 ** specified by the blocked connections bundled together into an array.
6987 ** This gives the application an opportunity to prioritize any actions
6988 ** related to the set of unblocked database connections.
6989 **
6990 ** <b>Deadlock Detection</b>
6991 **
6992 ** Assuming that after registering for an unlock-notify callback a
6993 ** database waits for the callback to be issued before taking any further
6994 ** action (a reasonable assumption), then using this API may cause the
6995 ** application to deadlock. For example, if connection X is waiting for
6996 ** connection Y's transaction to be concluded, and similarly connection
6997 ** Y is waiting on connection X's transaction, then neither connection
6998 ** will proceed and the system may remain deadlocked indefinitely.
6999 **
7000 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
7001 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
7002 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
7003 ** unlock-notify callback is registered. The system is said to be in
7004 ** a deadlocked state if connection A has registered for an unlock-notify
7005 ** callback on the conclusion of connection B's transaction, and connection
7006 ** B has itself registered for an unlock-notify callback when connection
7007 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
7008 ** the system is also considered to be deadlocked if connection B has
7009 ** registered for an unlock-notify callback on the conclusion of connection
7010 ** C's transaction, where connection C is waiting on connection A. ^Any
7011 ** number of levels of indirection are allowed.
7012 **
7013 ** <b>The "DROP TABLE" Exception</b>
7014 **
7015 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
7016 ** always appropriate to call sqlite3_unlock_notify(). There is however,
7017 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
7018 ** SQLite checks if there are any currently executing SELECT statements
7019 ** that belong to the same connection. If there are, SQLITE_LOCKED is
7020 ** returned. In this case there is no "blocking connection", so invoking
7021 ** sqlite3_unlock_notify() results in the unlock-notify callback being
7022 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
7023 ** or "DROP INDEX" query, an infinite loop might be the result.
7024 **
7025 ** One way around this problem is to check the extended error code returned
7026 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
7027 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
7028 ** the special "DROP TABLE/INDEX" case, the extended error code is just
7029 ** SQLITE_LOCKED.)^
7030 */
7031 SQLITE_API int sqlite3_unlock_notify(
7032 sqlite3 *pBlocked, /* Waiting connection */
7033 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
7034 void *pNotifyArg /* Argument to pass to xNotify */
7035 );
7036
7037
7038 /*
7039 ** CAPI3REF: String Comparison
7040 **
7041 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
7042 ** and extensions to compare the contents of two buffers containing UTF-8
7043 ** strings in a case-independent fashion, using the same definition of "case
7044 ** independence" that SQLite uses internally when comparing identifiers.
7045 */
7046 SQLITE_API int sqlite3_stricmp(const char *, const char *);
7047 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
7048
7049 /*
7050 ** CAPI3REF: String Globbing
7051 *
7052 ** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches
7053 ** the glob pattern P, and it returns non-zero if string X does not match
7054 ** the glob pattern P. ^The definition of glob pattern matching used in
7055 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
7056 ** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case
7057 ** sensitive.
7058 **
7059 ** Note that this routine returns zero on a match and non-zero if the strings
7060 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
7061 */
7062 SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
7063
7064 /*
7065 ** CAPI3REF: Error Logging Interface
7066 **
7067 ** ^The [sqlite3_log()] interface writes a message into the [error log]
7068 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
7069 ** ^If logging is enabled, the zFormat string and subsequent arguments are
7070 ** used with [sqlite3_snprintf()] to generate the final output string.
7071 **
7072 ** The sqlite3_log() interface is intended for use by extensions such as
7073 ** virtual tables, collating functions, and SQL functions. While there is
7074 ** nothing to prevent an application from calling sqlite3_log(), doing so
7075 ** is considered bad form.
7076 **
7077 ** The zFormat string must not be NULL.
7078 **
7079 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
7080 ** will not use dynamically allocated memory. The log message is stored in
7081 ** a fixed-length buffer on the stack. If the log message is longer than
7082 ** a few hundred characters, it will be truncated to the length of the
7083 ** buffer.
7084 */
7085 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
7086
7087 /*
7088 ** CAPI3REF: Write-Ahead Log Commit Hook
7089 **
7090 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
7091 ** will be invoked each time a database connection commits data to a
7092 ** [write-ahead log] (i.e. whenever a transaction is committed in
7093 ** [journal_mode | journal_mode=WAL mode]).
7094 **
7095 ** ^The callback is invoked by SQLite after the commit has taken place and
7096 ** the associated write-lock on the database released, so the implementation
7097 ** may read, write or [checkpoint] the database as required.
7098 **
7099 ** ^The first parameter passed to the callback function when it is invoked
7100 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
7101 ** registering the callback. ^The second is a copy of the database handle.
7102 ** ^The third parameter is the name of the database that was written to -
7103 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
7104 ** is the number of pages currently in the write-ahead log file,
7105 ** including those that were just committed.
7106 **
7107 ** The callback function should normally return [SQLITE_OK]. ^If an error
7108 ** code is returned, that error will propagate back up through the
7109 ** SQLite code base to cause the statement that provoked the callback
7110 ** to report an error, though the commit will have still occurred. If the
7111 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
7112 ** that does not correspond to any valid SQLite error code, the results
7113 ** are undefined.
7114 **
7115 ** A single database handle may have at most a single write-ahead log callback
7116 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
7117 ** previously registered write-ahead log callback. ^Note that the
7118 ** [sqlite3_wal_autocheckpoint()] interface and the
7119 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
7120 ** those overwrite any prior [sqlite3_wal_hook()] settings.
7121 */
7122 SQLITE_API void *sqlite3_wal_hook(
7123 sqlite3*,
7124 int(*)(void *,sqlite3*,const char*,int),
7125 void*
7126 );
7127
7128 /*
7129 ** CAPI3REF: Configure an auto-checkpoint
7130 **
7131 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
7132 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
7133 ** to automatically [checkpoint]
7134 ** after committing a transaction if there are N or
7135 ** more frames in the [write-ahead log] file. ^Passing zero or
7136 ** a negative value as the nFrame parameter disables automatic
7137 ** checkpoints entirely.
7138 **
7139 ** ^The callback registered by this function replaces any existing callback
7140 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
7141 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
7142 ** configured by this function.
7143 **
7144 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
7145 ** from SQL.
7146 **
7147 ** ^Every new [database connection] defaults to having the auto-checkpoint
7148 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
7149 ** pages. The use of this interface
7150 ** is only necessary if the default setting is found to be suboptimal
7151 ** for a particular application.
7152 */
7153 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
7154
7155 /*
7156 ** CAPI3REF: Checkpoint a database
7157 **
7158 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
7159 ** on [database connection] D to be [checkpointed]. ^If X is NULL or an
7160 ** empty string, then a checkpoint is run on all databases of
7161 ** connection D. ^If the database connection D is not in
7162 ** [WAL | write-ahead log mode] then this interface is a harmless no-op.
7163 **
7164 ** ^The [wal_checkpoint pragma] can be used to invoke this interface
7165 ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the
7166 ** [wal_autocheckpoint pragma] can be used to cause this interface to be
7167 ** run whenever the WAL reaches a certain size threshold.
7168 **
7169 ** See also: [sqlite3_wal_checkpoint_v2()]
7170 */
7171 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
7172
7173 /*
7174 ** CAPI3REF: Checkpoint a database
7175 **
7176 ** Run a checkpoint operation on WAL database zDb attached to database
7177 ** handle db. The specific operation is determined by the value of the
7178 ** eMode parameter:
7179 **
7180 ** <dl>
7181 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
7182 ** Checkpoint as many frames as possible without waiting for any database
7183 ** readers or writers to finish. Sync the db file if all frames in the log
7184 ** are checkpointed. This mode is the same as calling
7185 ** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked.
7186 **
7187 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
7188 ** This mode blocks (calls the busy-handler callback) until there is no
7189 ** database writer and all readers are reading from the most recent database
7190 ** snapshot. It then checkpoints all frames in the log file and syncs the
7191 ** database file. This call blocks database writers while it is running,
7192 ** but not database readers.
7193 **
7194 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
7195 ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after
7196 ** checkpointing the log file it blocks (calls the busy-handler callback)
7197 ** until all readers are reading from the database file only. This ensures
7198 ** that the next client to write to the database file restarts the log file
7199 ** from the beginning. This call blocks database writers while it is running,
7200 ** but not database readers.
7201 ** </dl>
7202 **
7203 ** If pnLog is not NULL, then *pnLog is set to the total number of frames in
7204 ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
7205 ** the total number of checkpointed frames (including any that were already
7206 ** checkpointed when this function is called). *pnLog and *pnCkpt may be
7207 ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
7208 ** If no values are available because of an error, they are both set to -1
7209 ** before returning to communicate this to the caller.
7210 **
7211 ** All calls obtain an exclusive "checkpoint" lock on the database file. If
7212 ** any other process is running a checkpoint operation at the same time, the
7213 ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a
7214 ** busy-handler configured, it will not be invoked in this case.
7215 **
7216 ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive
7217 ** "writer" lock on the database file. If the writer lock cannot be obtained
7218 ** immediately, and a busy-handler is configured, it is invoked and the writer
7219 ** lock retried until either the busy-handler returns 0 or the lock is
7220 ** successfully obtained. The busy-handler is also invoked while waiting for
7221 ** database readers as described above. If the busy-handler returns 0 before
7222 ** the writer lock is obtained or while waiting for database readers, the
7223 ** checkpoint operation proceeds from that point in the same way as
7224 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
7225 ** without blocking any further. SQLITE_BUSY is returned in this case.
7226 **
7227 ** If parameter zDb is NULL or points to a zero length string, then the
7228 ** specified operation is attempted on all WAL databases. In this case the
7229 ** values written to output parameters *pnLog and *pnCkpt are undefined. If
7230 ** an SQLITE_BUSY error is encountered when processing one or more of the
7231 ** attached WAL databases, the operation is still attempted on any remaining
7232 ** attached databases and SQLITE_BUSY is returned to the caller. If any other
7233 ** error occurs while processing an attached database, processing is abandoned
7234 ** and the error code returned to the caller immediately. If no error
7235 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
7236 ** databases, SQLITE_OK is returned.
7237 **
7238 ** If database zDb is the name of an attached database that is not in WAL
7239 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
7240 ** zDb is not NULL (or a zero length string) and is not the name of any
7241 ** attached database, SQLITE_ERROR is returned to the caller.
7242 */
7243 SQLITE_API int sqlite3_wal_checkpoint_v2(
7244 sqlite3 *db, /* Database handle */
7245 const char *zDb, /* Name of attached database (or NULL) */
7246 int eMode, /* SQLITE_CHECKPOINT_* value */
7247 int *pnLog, /* OUT: Size of WAL log in frames */
7248 int *pnCkpt /* OUT: Total number of frames checkpointed */
7249 );
7250
7251 /*
7252 ** CAPI3REF: Checkpoint operation parameters
7253 **
7254 ** These constants can be used as the 3rd parameter to
7255 ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()]
7256 ** documentation for additional information about the meaning and use of
7257 ** each of these values.
7258 */
7259 #define SQLITE_CHECKPOINT_PASSIVE 0
7260 #define SQLITE_CHECKPOINT_FULL 1
7261 #define SQLITE_CHECKPOINT_RESTART 2
7262
7263 /*
7264 ** CAPI3REF: Virtual Table Interface Configuration
7265 **
7266 ** This function may be called by either the [xConnect] or [xCreate] method
7267 ** of a [virtual table] implementation to configure
7268 ** various facets of the virtual table interface.
7269 **
7270 ** If this interface is invoked outside the context of an xConnect or
7271 ** xCreate virtual table method then the behavior is undefined.
7272 **
7273 ** At present, there is only one option that may be configured using
7274 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options
7275 ** may be added in the future.
7276 */
7277 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
7278
7279 /*
7280 ** CAPI3REF: Virtual Table Configuration Options
7281 **
7282 ** These macros define the various options to the
7283 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
7284 ** can use to customize and optimize their behavior.
7285 **
7286 ** <dl>
7287 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
7288 ** <dd>Calls of the form
7289 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
7290 ** where X is an integer. If X is zero, then the [virtual table] whose
7291 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
7292 ** support constraints. In this configuration (which is the default) if
7293 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
7294 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
7295 ** specified as part of the users SQL statement, regardless of the actual
7296 ** ON CONFLICT mode specified.
7297 **
7298 ** If X is non-zero, then the virtual table implementation guarantees
7299 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
7300 ** any modifications to internal or persistent data structures have been made.
7301 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
7302 ** is able to roll back a statement or database transaction, and abandon
7303 ** or continue processing the current SQL statement as appropriate.
7304 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
7305 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
7306 ** had been ABORT.
7307 **
7308 ** Virtual table implementations that are required to handle OR REPLACE
7309 ** must do so within the [xUpdate] method. If a call to the
7310 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
7311 ** CONFLICT policy is REPLACE, the virtual table implementation should
7312 ** silently replace the appropriate rows within the xUpdate callback and
7313 ** return SQLITE_OK. Or, if this is not possible, it may return
7314 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
7315 ** constraint handling.
7316 ** </dl>
7317 */
7318 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
7319
7320 /*
7321 ** CAPI3REF: Determine The Virtual Table Conflict Policy
7322 **
7323 ** This function may only be called from within a call to the [xUpdate] method
7324 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
7325 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
7326 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
7327 ** of the SQL statement that triggered the call to the [xUpdate] method of the
7328 ** [virtual table].
7329 */
7330 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
7331
7332 /*
7333 ** CAPI3REF: Conflict resolution modes
7334 **
7335 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
7336 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
7337 ** is for the SQL statement being evaluated.
7338 **
7339 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
7340 ** return value from the [sqlite3_set_authorizer()] callback and that
7341 ** [SQLITE_ABORT] is also a [result code].
7342 */
7343 #define SQLITE_ROLLBACK 1
7344 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
7345 #define SQLITE_FAIL 3
7346 /* #define SQLITE_ABORT 4 // Also an error code */
7347 #define SQLITE_REPLACE 5
7348
7349
7350
7351 /*
7352 ** Undo the hack that converts floating point types to integer for
7353 ** builds on processors without floating point support.
7354 */
7355 #ifdef SQLITE_OMIT_FLOATING_POINT
7356 # undef double
7357 #endif
7358
7359 #ifdef __cplusplus
7360 } /* End of the 'extern "C"' block */
7361 #endif
7362 #endif /* _SQLITE3_H_ */
7363
7364 /*
7365 ** 2010 August 30
7366 **
7367 ** The author disclaims copyright to this source code. In place of
7368 ** a legal notice, here is a blessing:
7369 **
7370 ** May you do good and not evil.
7371 ** May you find forgiveness for yourself and forgive others.
7372 ** May you share freely, never taking more than you give.
7373 **
7374 *************************************************************************
7375 */
7376
7377 #ifndef _SQLITE3RTREE_H_
7378 #define _SQLITE3RTREE_H_
7379
7380
7381 #ifdef __cplusplus
7382 extern "C" {
7383 #endif
7384
7385 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
7386 typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
7387
7388 /* The double-precision datatype used by RTree depends on the
7389 ** SQLITE_RTREE_INT_ONLY compile-time option.
7390 */
7391 #ifdef SQLITE_RTREE_INT_ONLY
7392 typedef sqlite3_int64 sqlite3_rtree_dbl;
7393 #else
7394 typedef double sqlite3_rtree_dbl;
7395 #endif
7396
7397 /*
7398 ** Register a geometry callback named zGeom that can be used as part of an
7399 ** R-Tree geometry query as follows:
7400 **
7401 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
7402 */
7403 SQLITE_API int sqlite3_rtree_geometry_callback(
7404 sqlite3 *db,
7405 const char *zGeom,
7406 int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
7407 void *pContext
7408 );
7409
7410
7411 /*
7412 ** A pointer to a structure of the following type is passed as the first
7413 ** argument to callbacks registered using rtree_geometry_callback().
7414 */
7415 struct sqlite3_rtree_geometry {
7416 void *pContext; /* Copy of pContext passed to s_r_g_c() */
7417 int nParam; /* Size of array aParam[] */
7418 sqlite3_rtree_dbl *aParam; /* Parameters passed to SQL geom function */
7419 void *pUser; /* Callback implementation user data */
7420 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */
7421 };
7422
7423 /*
7424 ** Register a 2nd-generation geometry callback named zScore that can be
7425 ** used as part of an R-Tree geometry query as follows:
7426 **
7427 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
7428 */
7429 SQLITE_API int sqlite3_rtree_query_callback(
7430 sqlite3 *db,
7431 const char *zQueryFunc,
7432 int (*xQueryFunc)(sqlite3_rtree_query_info*),
7433 void *pContext,
7434 void (*xDestructor)(void*)
7435 );
7436
7437
7438 /*
7439 ** A pointer to a structure of the following type is passed as the
7440 ** argument to scored geometry callback registered using
7441 ** sqlite3_rtree_query_callback().
7442 **
7443 ** Note that the first 5 fields of this structure are identical to
7444 ** sqlite3_rtree_geometry. This structure is a subclass of
7445 ** sqlite3_rtree_geometry.
7446 */
7447 struct sqlite3_rtree_query_info {
7448 void *pContext; /* pContext from when function registered */
7449 int nParam; /* Number of function parameters */
7450 sqlite3_rtree_dbl *aParam; /* value of function parameters */
7451 void *pUser; /* callback can use this, if desired */
7452 void (*xDelUser)(void*); /* function to free pUser */
7453 sqlite3_rtree_dbl *aCoord; /* Coordinates of node or entry to check */
7454 unsigned int *anQueue; /* Number of pending entries in the queue */
7455 int nCoord; /* Number of coordinates */
7456 int iLevel; /* Level of current node or entry */
7457 int mxLevel; /* The largest iLevel value in the tree */
7458 sqlite3_int64 iRowid; /* Rowid for current entry */
7459 sqlite3_rtree_dbl rParentScore; /* Score of parent node */
7460 int eParentWithin; /* Visibility of parent node */
7461 int eWithin; /* OUT: Visiblity */
7462 sqlite3_rtree_dbl rScore; /* OUT: Write the score here */
7463 };
7464
7465 /*
7466 ** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
7467 */
7468 #define NOT_WITHIN 0 /* Object completely outside of query region */
7469 #define PARTLY_WITHIN 1 /* Object partially overlaps query region */
7470 #define FULLY_WITHIN 2 /* Object fully contained within query region */
7471
7472
7473 #ifdef __cplusplus
7474 } /* end of the 'extern "C"' block */
7475 #endif
7476
7477 #endif /* ifndef _SQLITE3RTREE_H_ */
7478
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