Warning: That file was not part of the compilation database. It may have many parsing errors.

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
41extern "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*/
144SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
145SQLITE_API const char *sqlite3_libversion(void);
146SQLITE_API const char *sqlite3_sourceid(void);
147SQLITE_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
172SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
173SQLITE_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*/
212SQLITE_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*/
228typedef 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
256typedef sqlite_int64 sqlite3_int64;
257typedef 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*/
308SQLITE_API int sqlite3_close(sqlite3*);
309SQLITE_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*/
316typedef 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*/
379SQLITE_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*/
637typedef struct sqlite3_file sqlite3_file;
638struct 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*/
732typedef struct sqlite3_io_methods sqlite3_io_methods;
733struct 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*/
991typedef 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*/
1150typedef struct sqlite3_vfs sqlite3_vfs;
1151typedef void (*sqlite3_syscall_ptr)(void);
1152struct 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*/
1328SQLITE_API int sqlite3_initialize(void);
1329SQLITE_API int sqlite3_shutdown(void);
1330SQLITE_API int sqlite3_os_init(void);
1331SQLITE_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*/
1362SQLITE_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*/
1380SQLITE_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*/
1445typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1446struct 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*/
1829SQLITE_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*/
1880SQLITE_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*/
1934SQLITE_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*/
1960SQLITE_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*/
1999SQLITE_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*/
2034SQLITE_API int sqlite3_complete(const char *sql);
2035SQLITE_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*/
2101SQLITE_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*/
2121SQLITE_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*/
2195SQLITE_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);
2203SQLITE_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*/
2299SQLITE_API char *sqlite3_mprintf(const char*,...);
2300SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2301SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2302SQLITE_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*/
2374SQLITE_API void *sqlite3_malloc(int);
2375SQLITE_API void *sqlite3_realloc(void*, int);
2376SQLITE_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*/
2401SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2402SQLITE_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*/
2424SQLITE_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*/
2506SQLITE_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*/
2610SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2611SQLITE_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*/
2645SQLITE_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*/
2874SQLITE_API int sqlite3_open(
2875 const char *filename, /* Database filename (UTF-8) */
2876 sqlite3 **ppDb /* OUT: SQLite db handle */
2877);
2878SQLITE_API int sqlite3_open16(
2879 const void *filename, /* Database filename (UTF-16) */
2880 sqlite3 **ppDb /* OUT: SQLite db handle */
2881);
2882SQLITE_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*/
2928SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
2929SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
2930SQLITE_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*/
2971SQLITE_API int sqlite3_errcode(sqlite3 *db);
2972SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
2973SQLITE_API const char *sqlite3_errmsg(sqlite3*);
2974SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
2975SQLITE_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*/
3001typedef 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*/
3042SQLITE_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*/
3189SQLITE_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);
3196SQLITE_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);
3203SQLITE_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);
3210SQLITE_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*/
3225SQLITE_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*/
3256SQLITE_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*/
3275SQLITE_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*/
3314typedef 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*/
3328typedef 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*/
3425SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3426SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
3427SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
3428SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3429SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
3430SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
3431SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3432SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3433SQLITE_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*/
3453SQLITE_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*/
3480SQLITE_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*/
3496SQLITE_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*/
3505SQLITE_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*/
3516SQLITE_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*/
3544SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
3545SQLITE_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*/
3592SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
3593SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
3594SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
3595SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
3596SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
3597SQLITE_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*/
3628SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
3629SQLITE_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*/
3708SQLITE_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*/
3728SQLITE_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*/
3924SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
3925SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
3926SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
3927SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
3928SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
3929SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
3930SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
3931SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
3932SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
3933SQLITE_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*/
3960SQLITE_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*/
3986SQLITE_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*/
4085SQLITE_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);
4095SQLITE_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);
4105SQLITE_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
4151SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
4152SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
4153SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4154SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
4155SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
4156SQLITE_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*/
4205SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
4206SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
4207SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
4208SQLITE_API double sqlite3_value_double(sqlite3_value*);
4209SQLITE_API int sqlite3_value_int(sqlite3_value*);
4210SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
4211SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
4212SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
4213SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
4214SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
4215SQLITE_API int sqlite3_value_type(sqlite3_value*);
4216SQLITE_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*/
4260SQLITE_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*/
4274SQLITE_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*/
4285SQLITE_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*/
4337SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
4338SQLITE_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*/
4355typedef 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*/
4469SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4470SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
4471SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
4472SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
4473SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
4474SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
4475SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
4476SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
4477SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4478SQLITE_API void sqlite3_result_null(sqlite3_context*);
4479SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4480SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4481SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4482SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4483SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4484SQLITE_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*/
4565SQLITE_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);
4572SQLITE_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);
4580SQLITE_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*/
4614SQLITE_API int sqlite3_collation_needed(
4615 sqlite3*,
4616 void*,
4617 void(*)(void*,sqlite3*,int eTextRep,const char*)
4618);
4619SQLITE_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*/
4633SQLITE_API int sqlite3_key(
4634 sqlite3 *db, /* Database to be rekeyed */
4635 const void *pKey, int nKey /* The key */
4636);
4637SQLITE_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*/
4651SQLITE_API int sqlite3_rekey(
4652 sqlite3 *db, /* Database to be rekeyed */
4653 const void *pKey, int nKey /* The new key */
4654);
4655SQLITE_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*/
4665SQLITE_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*/
4675SQLITE_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*/
4697SQLITE_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*/
4743SQLITE_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*/
4780SQLITE_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*/
4803SQLITE_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*/
4815SQLITE_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*/
4831SQLITE_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*/
4840SQLITE_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*/
4855SQLITE_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*/
4903SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
4904SQLITE_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*/
4954SQLITE_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*/
4989SQLITE_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*/
5005SQLITE_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*/
5018SQLITE_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*/
5070SQLITE_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*/
5081SQLITE_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*/
5146SQLITE_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*/
5192SQLITE_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*/
5212SQLITE_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*/
5250SQLITE_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*/
5262SQLITE_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*/
5270SQLITE_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*/
5284typedef struct sqlite3_vtab sqlite3_vtab;
5285typedef struct sqlite3_index_info sqlite3_index_info;
5286typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
5287typedef 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*/
5305struct 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*/
5405struct 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*/
5473SQLITE_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);
5479SQLITE_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*/
5505struct 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*/
5529struct 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*/
5542SQLITE_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*/
5560SQLITE_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*/
5584typedef 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*/
5645SQLITE_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*/
5677SQLITE_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*/
5701SQLITE_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*/
5716SQLITE_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*/
5744SQLITE_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*/
5782SQLITE_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*/
5813SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
5814SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
5815SQLITE_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*/
5930SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
5931SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
5932SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
5933SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
5934SQLITE_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*/
6001typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
6002struct 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
6044SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
6045SQLITE_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*/
6078SQLITE_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*/
6112SQLITE_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*/
6131SQLITE_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*/
6194SQLITE_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*/
6312SQLITE_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*/
6441SQLITE_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*/
6496typedef 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*/
6508typedef struct sqlite3_pcache_page sqlite3_pcache_page;
6509struct 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*/
6673typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
6674struct 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*/
6696typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
6697struct 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*/
6722typedef 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*/
6906SQLITE_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);
6912SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
6913SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
6914SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
6915SQLITE_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*/
7031SQLITE_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*/
7046SQLITE_API int sqlite3_stricmp(const char *, const char *);
7047SQLITE_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*/
7062SQLITE_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*/
7085SQLITE_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*/
7122SQLITE_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*/
7153SQLITE_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*/
7171SQLITE_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*/
7243SQLITE_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*/
7277SQLITE_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*/
7330SQLITE_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
7382extern "C" {
7383#endif
7384
7385typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
7386typedef 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*/
7403SQLITE_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*/
7415struct 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*/
7429SQLITE_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*/
7447struct 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
7479

Warning: That file was not part of the compilation database. It may have many parsing errors.