2** 2001-09-15
4** The author disclaims copyright to this source code. In place of
5** a legal notice, here is a blessing:
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.
12** This header file defines the interface that the SQLite library
13** presents to client programs. If a C-function, structure, datatype,
14** or constant definition does not appear in this file, then it is
15** not a published API of SQLite, is subject to change without
16** notice, and should not be referenced by programs that use SQLite.
18** Some of the definitions that are in this file are marked as
19** "experimental". Experimental interfaces are normally new
20** features recently added to SQLite. We do not anticipate changes
21** to experimental interfaces but reserve the right to make minor changes
22** if experience from use "in the wild" suggest such changes are prudent.
24** The official C-language API documentation for SQLite is derived
25** from comments in this file. This file is the authoritative source
26** on how SQLite interfaces are supposed to operate.
28** The name of this file under configuration management is "sqlite.h.in".
29** The makefile makes some minor changes to this file (such as inserting
30** the version number) and changes its name to "sqlite3.h" as
31** part of the build process.
33#ifndef SQLITE3_H
34#define SQLITE3_H
35#include <stdarg.h> /* Needed for the definition of va_list */
38** Make sure we can call this stuff from C++.
40#ifdef __cplusplus
41extern "C" {
46** Provide the ability to override linkage features of the interface.
49# define SQLITE_EXTERN extern
51#ifndef SQLITE_API
52# define SQLITE_API
54#ifndef SQLITE_CDECL
55# define SQLITE_CDECL
67# define SQLITE_SYSAPI
71** These no-op macros are used in front of interfaces to mark those
72** interfaces as either deprecated or experimental. New applications
73** should not use deprecated interfaces - they are supported for backwards
74** compatibility only. Application writers should be aware that
75** experimental interfaces are subject to change in point releases.
77** These macros used to resolve to various kinds of compiler magic that
78** would generate warning messages when they were used. But that
79** compiler magic ended up generating such a flurry of bug reports
80** that we have taken it all out and gone back to using simple
81** noop macros.
87** Ensure these symbols were not defined by some previous header file.
97** CAPI3REF: Compile-Time Library Version Numbers
99** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
100** evaluates to a string literal that is the SQLite version in the
101** format "X.Y.Z" where X is the major version number (always 3 for
102** SQLite3) and Y is the minor version number and Z is the release number.)^
103** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
104** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
105** numbers used in [SQLITE_VERSION].)^
106** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
107** be larger than the release from which it is derived. Either Y will
108** be held constant and Z will be incremented or else Y will be incremented
109** and Z will be reset to zero.
111** Since [version 3.6.18] ([dateof:3.6.18]),
112** SQLite source code has been stored in the
113** <a href="http://www.fossil-scm.org/">Fossil configuration management
114** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to
115** a string which identifies a particular check-in of SQLite
116** within its configuration management system. ^The SQLITE_SOURCE_ID
117** string contains the date and time of the check-in (UTC) and a SHA1
118** or SHA3-256 hash of the entire source tree. If the source code has
119** been edited in any way since it was last checked in, then the last
120** four hexadecimal digits of the hash may be modified.
122** See also: [sqlite3_libversion()],
123** [sqlite3_libversion_number()], [sqlite3_sourceid()],
124** [sqlite_version()] and [sqlite_source_id()].
126#define SQLITE_VERSION "3.28.0"
127#define SQLITE_VERSION_NUMBER 3028000
128#define SQLITE_SOURCE_ID "2019-04-16 19:49:53 884b4b7e502b4e991677b53971277adfaf0a04a284f8e483e2553d0f83156b50"
131** CAPI3REF: Run-Time Library Version Numbers
132** KEYWORDS: sqlite3_version sqlite3_sourceid
134** These interfaces provide the same information as the [SQLITE_VERSION],
135** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
136** but are associated with the library instead of the header file. ^(Cautious
137** programmers might include assert() statements in their application to
138** verify that values returned by these interfaces match the macros in
139** the header, and thus ensure that the application is
140** compiled with matching library and header files.
142** <blockquote><pre>
143** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
144** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
145** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
146** </pre></blockquote>)^
148** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
149** macro. ^The sqlite3_libversion() function returns a pointer to the
150** to the sqlite3_version[] string constant. The sqlite3_libversion()
151** function is provided for use in DLLs since DLL users usually do not have
152** direct access to string constants within the DLL. ^The
153** sqlite3_libversion_number() function returns an integer equal to
154** [SQLITE_VERSION_NUMBER]. ^(The sqlite3_sourceid() function returns
155** a pointer to a string constant whose value is the same as the
156** [SQLITE_SOURCE_ID] C preprocessor macro. Except if SQLite is built
157** using an edited copy of [the amalgamation], then the last four characters
158** of the hash might be different from [SQLITE_SOURCE_ID].)^
160** See also: [sqlite_version()] and [sqlite_source_id()].
162SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
163SQLITE_API const char *sqlite3_libversion(void);
164SQLITE_API const char *sqlite3_sourceid(void);
165SQLITE_API int sqlite3_libversion_number(void);
168** CAPI3REF: Run-Time Library Compilation Options Diagnostics
170** ^The sqlite3_compileoption_used() function returns 0 or 1
171** indicating whether the specified option was defined at
172** compile time. ^The SQLITE_ prefix may be omitted from the
173** option name passed to sqlite3_compileoption_used().
175** ^The sqlite3_compileoption_get() function allows iterating
176** over the list of options that were defined at compile time by
177** returning the N-th compile time option string. ^If N is out of range,
178** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
179** prefix is omitted from any strings returned by
180** sqlite3_compileoption_get().
182** ^Support for the diagnostic functions sqlite3_compileoption_used()
183** and sqlite3_compileoption_get() may be omitted by specifying the
184** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
186** See also: SQL functions [sqlite_compileoption_used()] and
187** [sqlite_compileoption_get()] and the [compile_options pragma].
190SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
191SQLITE_API const char *sqlite3_compileoption_get(int N);
193# define sqlite3_compileoption_used(X) 0
194# define sqlite3_compileoption_get(X) ((void*)0)
198** CAPI3REF: Test To See If The Library Is Threadsafe
200** ^The sqlite3_threadsafe() function returns zero if and only if
201** SQLite was compiled with mutexing code omitted due to the
202** [SQLITE_THREADSAFE] compile-time option being set to 0.
204** SQLite can be compiled with or without mutexes. When
205** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
206** are enabled and SQLite is threadsafe. When the
207** [SQLITE_THREADSAFE] macro is 0,
208** the mutexes are omitted. Without the mutexes, it is not safe
209** to use SQLite concurrently from more than one thread.
211** Enabling mutexes incurs a measurable performance penalty.
212** So if speed is of utmost importance, it makes sense to disable
213** the mutexes. But for maximum safety, mutexes should be enabled.
214** ^The default behavior is for mutexes to be enabled.
216** This interface can be used by an application to make sure that the
217** version of SQLite that it is linking against was compiled with
218** the desired setting of the [SQLITE_THREADSAFE] macro.
220** This interface only reports on the compile-time mutex setting
221** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
222** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
223** can be fully or partially disabled using a call to [sqlite3_config()]
225** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the
226** sqlite3_threadsafe() function shows only the compile-time setting of
227** thread safety, not any run-time changes to that setting made by
228** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
229** is unchanged by calls to sqlite3_config().)^
231** See the [threading mode] documentation for additional information.
233SQLITE_API int sqlite3_threadsafe(void);
236** CAPI3REF: Database Connection Handle
237** KEYWORDS: {database connection} {database connections}
239** Each open SQLite database is represented by a pointer to an instance of
240** the opaque structure named "sqlite3". It is useful to think of an sqlite3
241** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
242** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
243** and [sqlite3_close_v2()] are its destructors. There are many other
244** interfaces (such as
245** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
246** [sqlite3_busy_timeout()] to name but three) that are methods on an
247** sqlite3 object.
249typedef struct sqlite3 sqlite3;
252** CAPI3REF: 64-Bit Integer Types
253** KEYWORDS: sqlite_int64 sqlite_uint64
255** Because there is no cross-platform way to specify 64-bit integer types
256** SQLite includes typedefs for 64-bit signed and unsigned integers.
258** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
259** The sqlite_int64 and sqlite_uint64 types are supported for backwards
260** compatibility only.
262** ^The sqlite3_int64 and sqlite_int64 types can store integer values
263** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
264** sqlite3_uint64 and sqlite_uint64 types can store integer values
265** between 0 and +18446744073709551615 inclusive.
267#ifdef SQLITE_INT64_TYPE
268 typedef SQLITE_INT64_TYPE sqlite_int64;
269# ifdef SQLITE_UINT64_TYPE
270 typedef SQLITE_UINT64_TYPE sqlite_uint64;
271# else
272 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
273# endif
274#elif defined(_MSC_VER) || defined(__BORLANDC__)
275 typedef __int64 sqlite_int64;
276 typedef unsigned __int64 sqlite_uint64;
278 typedef long long int sqlite_int64;
279 typedef unsigned long long int sqlite_uint64;
281typedef sqlite_int64 sqlite3_int64;
282typedef sqlite_uint64 sqlite3_uint64;
285** If compiling for a processor that lacks floating point support,
286** substitute integer for floating-point.
289# define double sqlite3_int64
293** CAPI3REF: Closing A Database Connection
294** DESTRUCTOR: sqlite3
296** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
297** for the [sqlite3] object.
298** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
299** the [sqlite3] object is successfully destroyed and all associated
300** resources are deallocated.
302** ^If the database connection is associated with unfinalized prepared
303** statements or unfinished sqlite3_backup objects then sqlite3_close()
304** will leave the database connection open and return [SQLITE_BUSY].
305** ^If sqlite3_close_v2() is called with unfinalized prepared statements
306** and/or unfinished sqlite3_backups, then the database connection becomes
307** an unusable "zombie" which will automatically be deallocated when the
308** last prepared statement is finalized or the last sqlite3_backup is
309** finished. The sqlite3_close_v2() interface is intended for use with
310** host languages that are garbage collected, and where the order in which
311** destructors are called is arbitrary.
313** Applications should [sqlite3_finalize | finalize] all [prepared statements],
314** [sqlite3_blob_close | close] all [BLOB handles], and
315** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
316** with the [sqlite3] object prior to attempting to close the object. ^If
317** sqlite3_close_v2() is called on a [database connection] that still has
318** outstanding [prepared statements], [BLOB handles], and/or
319** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
320** of resources is deferred until all [prepared statements], [BLOB handles],
321** and [sqlite3_backup] objects are also destroyed.
323** ^If an [sqlite3] object is destroyed while a transaction is open,
324** the transaction is automatically rolled back.
326** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
327** must be either a NULL
328** pointer or an [sqlite3] object pointer obtained
329** from [sqlite3_open()], [sqlite3_open16()], or
330** [sqlite3_open_v2()], and not previously closed.
331** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
332** argument is a harmless no-op.
334SQLITE_API int sqlite3_close(sqlite3*);
335SQLITE_API int sqlite3_close_v2(sqlite3*);
338** The type for a callback function.
339** This is legacy and deprecated. It is included for historical
340** compatibility and is not documented.
342typedef int (*sqlite3_callback)(void*,int,char**, char**);
345** CAPI3REF: One-Step Query Execution Interface
346** METHOD: sqlite3
348** The sqlite3_exec() interface is a convenience wrapper around
349** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
350** that allows an application to run multiple statements of SQL
351** without having to use a lot of C code.
353** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
354** semicolon-separate SQL statements passed into its 2nd argument,
355** in the context of the [database connection] passed in as its 1st
356** argument. ^If the callback function of the 3rd argument to
357** sqlite3_exec() is not NULL, then it is invoked for each result row
358** coming out of the evaluated SQL statements. ^The 4th argument to
359** sqlite3_exec() is relayed through to the 1st argument of each
360** callback invocation. ^If the callback pointer to sqlite3_exec()
361** is NULL, then no callback is ever invoked and result rows are
362** ignored.
364** ^If an error occurs while evaluating the SQL statements passed into
365** sqlite3_exec(), then execution of the current statement stops and
366** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
367** is not NULL then any error message is written into memory obtained
368** from [sqlite3_malloc()] and passed back through the 5th parameter.
369** To avoid memory leaks, the application should invoke [sqlite3_free()]
370** on error message strings returned through the 5th parameter of
371** sqlite3_exec() after the error message string is no longer needed.
372** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
373** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
374** NULL before returning.
376** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
377** routine returns SQLITE_ABORT without invoking the callback again and
378** without running any subsequent SQL statements.
380** ^The 2nd argument to the sqlite3_exec() callback function is the
381** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
382** callback is an array of pointers to strings obtained as if from
383** [sqlite3_column_text()], one for each column. ^If an element of a
384** result row is NULL then the corresponding string pointer for the
385** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
386** sqlite3_exec() callback is an array of pointers to strings where each
387** entry represents the name of corresponding result column as obtained
388** from [sqlite3_column_name()].
390** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
391** to an empty string, or a pointer that contains only whitespace and/or
392** SQL comments, then no SQL statements are evaluated and the database
393** is not changed.
395** Restrictions:
397** <ul>
398** <li> The application must ensure that the 1st parameter to sqlite3_exec()
399** is a valid and open [database connection].
400** <li> The application must not close the [database connection] specified by
401** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
402** <li> The application must not modify the SQL statement text passed into
403** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
404** </ul>
406SQLITE_API int sqlite3_exec(
407 sqlite3*, /* An open database */
408 const char *sql, /* SQL to be evaluated */
409 int (*callback)(void*,int,char**,char**), /* Callback function */
410 void *, /* 1st argument to callback */
411 char **errmsg /* Error msg written here */
415** CAPI3REF: Result Codes
416** KEYWORDS: {result code definitions}
418** Many SQLite functions return an integer result code from the set shown
419** here in order to indicate success or failure.
421** New error codes may be added in future versions of SQLite.
423** See also: [extended result code definitions]
425#define SQLITE_OK 0 /* Successful result */
426/* beginning-of-error-codes */
427#define SQLITE_ERROR 1 /* Generic error */
428#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
429#define SQLITE_PERM 3 /* Access permission denied */
430#define SQLITE_ABORT 4 /* Callback routine requested an abort */
431#define SQLITE_BUSY 5 /* The database file is locked */
432#define SQLITE_LOCKED 6 /* A table in the database is locked */
433#define SQLITE_NOMEM 7 /* A malloc() failed */
434#define SQLITE_READONLY 8 /* Attempt to write a readonly database */
435#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
436#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
437#define SQLITE_CORRUPT 11 /* The database disk image is malformed */
438#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
439#define SQLITE_FULL 13 /* Insertion failed because database is full */
440#define SQLITE_CANTOPEN 14 /* Unable to open the database file */
441#define SQLITE_PROTOCOL 15 /* Database lock protocol error */
442#define SQLITE_EMPTY 16 /* Internal use only */
443#define SQLITE_SCHEMA 17 /* The database schema changed */
444#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
445#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
446#define SQLITE_MISMATCH 20 /* Data type mismatch */
447#define SQLITE_MISUSE 21 /* Library used incorrectly */
448#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
449#define SQLITE_AUTH 23 /* Authorization denied */
450#define SQLITE_FORMAT 24 /* Not used */
451#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
452#define SQLITE_NOTADB 26 /* File opened that is not a database file */
453#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */
454#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */
455#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
456#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
457/* end-of-error-codes */
460** CAPI3REF: Extended Result Codes
461** KEYWORDS: {extended result code definitions}
463** In its default configuration, SQLite API routines return one of 30 integer
464** [result codes]. However, experience has shown that many of
465** these result codes are too coarse-grained. They do not provide as
466** much information about problems as programmers might like. In an effort to
467** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
468** and later) include
469** support for additional result codes that provide more detailed information
470** about errors. These [extended result codes] are enabled or disabled
471** on a per database connection basis using the
472** [sqlite3_extended_result_codes()] API. Or, the extended code for
473** the most recent error can be obtained using
474** [sqlite3_extended_errcode()].
479#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
490#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
493#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
494#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
500#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
502#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
505#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8))
506#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8))
518#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
541#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8))
545** CAPI3REF: Flags For File Open Operations
547** These bit values are intended for use in the
548** 3rd parameter to the [sqlite3_open_v2()] interface and
549** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
551#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
552#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
553#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
554#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
555#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
556#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
557#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
558#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
559#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
560#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
561#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
562#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
563#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
564#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
565#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
566#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
567#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
568#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
569#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
570#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
572/* Reserved: 0x00F00000 */
575** CAPI3REF: Device Characteristics
577** The xDeviceCharacteristics method of the [sqlite3_io_methods]
578** object returns an integer which is a vector of these
579** bit values expressing I/O characteristics of the mass storage
580** device that holds the file that the [sqlite3_io_methods]
581** refers to.
583** The SQLITE_IOCAP_ATOMIC property means that all writes of
584** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
585** mean that writes of blocks that are nnn bytes in size and
586** are aligned to an address which is an integer multiple of
587** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
588** that when data is appended to a file, the data is appended
589** first then the size of the file is extended, never the other
590** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
591** information is written to disk in the same order as calls
592** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
593** after reboot following a crash or power loss, the only bytes in a
594** file that were written at the application level might have changed
595** and that adjacent bytes, even bytes within the same sector are
596** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
597** flag indicates that a file cannot be deleted when open. The
598** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
599** read-only media and cannot be changed even by processes with
600** elevated privileges.
602** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
603** filesystem supports doing multiple write operations atomically when those
604** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
607#define SQLITE_IOCAP_ATOMIC 0x00000001
608#define SQLITE_IOCAP_ATOMIC512 0x00000002
609#define SQLITE_IOCAP_ATOMIC1K 0x00000004
610#define SQLITE_IOCAP_ATOMIC2K 0x00000008
611#define SQLITE_IOCAP_ATOMIC4K 0x00000010
612#define SQLITE_IOCAP_ATOMIC8K 0x00000020
613#define SQLITE_IOCAP_ATOMIC16K 0x00000040
614#define SQLITE_IOCAP_ATOMIC32K 0x00000080
615#define SQLITE_IOCAP_ATOMIC64K 0x00000100
616#define SQLITE_IOCAP_SAFE_APPEND 0x00000200
617#define SQLITE_IOCAP_SEQUENTIAL 0x00000400
620#define SQLITE_IOCAP_IMMUTABLE 0x00002000
621#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000
624** CAPI3REF: File Locking Levels
626** SQLite uses one of these integer values as the second
627** argument to calls it makes to the xLock() and xUnlock() methods
628** of an [sqlite3_io_methods] object.
630#define SQLITE_LOCK_NONE 0
637** CAPI3REF: Synchronization Type Flags
639** When SQLite invokes the xSync() method of an
640** [sqlite3_io_methods] object it uses a combination of
641** these integer values as the second argument.
643** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
644** sync operation only needs to flush data to mass storage. Inode
645** information need not be flushed. If the lower four bits of the flag
646** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
647** If the lower four bits equal SQLITE_SYNC_FULL, that means
648** to use Mac OS X style fullsync instead of fsync().
650** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
651** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
652** settings. The [synchronous pragma] determines when calls to the
653** xSync VFS method occur and applies uniformly across all platforms.
654** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
655** energetic or rigorous or forceful the sync operations are and
656** only make a difference on Mac OSX for the default SQLite code.
657** (Third-party VFS implementations might also make the distinction
658** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
659** operating systems natively supported by SQLite, only Mac OSX
660** cares about the difference.)
662#define SQLITE_SYNC_NORMAL 0x00002
663#define SQLITE_SYNC_FULL 0x00003
664#define SQLITE_SYNC_DATAONLY 0x00010
667** CAPI3REF: OS Interface Open File Handle
669** An [sqlite3_file] object represents an open file in the
670** [sqlite3_vfs | OS interface layer]. Individual OS interface
671** implementations will
672** want to subclass this object by appending additional fields
673** for their own use. The pMethods entry is a pointer to an
674** [sqlite3_io_methods] object that defines methods for performing
675** I/O operations on the open file.
677typedef struct sqlite3_file sqlite3_file;
678struct sqlite3_file {
679 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
683** CAPI3REF: OS Interface File Virtual Methods Object
685** Every file opened by the [sqlite3_vfs.xOpen] method populates an
686** [sqlite3_file] object (or, more commonly, a subclass of the
687** [sqlite3_file] object) with a pointer to an instance of this object.
688** This object defines the methods used to perform various operations
689** against the open file represented by the [sqlite3_file] object.
691** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
692** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
693** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
694** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
695** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
696** to NULL.
698** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
699** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
700** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
701** flag may be ORed in to indicate that only the data of the file
702** and not its inode needs to be synced.
704** The integer values to xLock() and xUnlock() are one of
705** <ul>
706** <li> [SQLITE_LOCK_NONE],
707** <li> [SQLITE_LOCK_SHARED],
709** <li> [SQLITE_LOCK_PENDING], or
711** </ul>
712** xLock() increases the lock. xUnlock() decreases the lock.
713** The xCheckReservedLock() method checks whether any database connection,
714** either in this process or in some other process, is holding a RESERVED,
715** PENDING, or EXCLUSIVE lock on the file. It returns true
716** if such a lock exists and false otherwise.
718** The xFileControl() method is a generic interface that allows custom
719** VFS implementations to directly control an open file using the
720** [sqlite3_file_control()] interface. The second "op" argument is an
721** integer opcode. The third argument is a generic pointer intended to
722** point to a structure that may contain arguments or space in which to
723** write return values. Potential uses for xFileControl() might be
724** functions to enable blocking locks with timeouts, to change the
725** locking strategy (for example to use dot-file locks), to inquire
726** about the status of a lock, or to break stale locks. The SQLite
727** core reserves all opcodes less than 100 for its own use.
728** A [file control opcodes | list of opcodes] less than 100 is available.
729** Applications that define a custom xFileControl method should use opcodes
730** greater than 100 to avoid conflicts. VFS implementations should
731** return [SQLITE_NOTFOUND] for file control opcodes that they do not
732** recognize.
734** The xSectorSize() method returns the sector size of the
735** device that underlies the file. The sector size is the
736** minimum write that can be performed without disturbing
737** other bytes in the file. The xDeviceCharacteristics()
738** method returns a bit vector describing behaviors of the
739** underlying device:
741** <ul>
743** <li> [SQLITE_IOCAP_ATOMIC512]
757** </ul>
759** The SQLITE_IOCAP_ATOMIC property means that all writes of
760** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
761** mean that writes of blocks that are nnn bytes in size and
762** are aligned to an address which is an integer multiple of
763** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
764** that when data is appended to a file, the data is appended
765** first then the size of the file is extended, never the other
766** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
767** information is written to disk in the same order as calls
768** to xWrite().
770** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
771** in the unread portions of the buffer with zeros. A VFS that
772** fails to zero-fill short reads might seem to work. However,
773** failure to zero-fill short reads will eventually lead to
774** database corruption.
776typedef struct sqlite3_io_methods sqlite3_io_methods;
777struct sqlite3_io_methods {
778 int iVersion;
779 int (*xClose)(sqlite3_file*);
780 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
781 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
782 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
783 int (*xSync)(sqlite3_file*, int flags);
784 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
785 int (*xLock)(sqlite3_file*, int);
786 int (*xUnlock)(sqlite3_file*, int);
787 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
788 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
789 int (*xSectorSize)(sqlite3_file*);
790 int (*xDeviceCharacteristics)(sqlite3_file*);
791 /* Methods above are valid for version 1 */
792 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
793 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
794 void (*xShmBarrier)(sqlite3_file*);
795 int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
796 /* Methods above are valid for version 2 */
797 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
798 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
799 /* Methods above are valid for version 3 */
800 /* Additional methods may be added in future releases */
804** CAPI3REF: Standard File Control Opcodes
805** KEYWORDS: {file control opcodes} {file control opcode}
807** These integer constants are opcodes for the xFileControl method
808** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
809** interface.
811** <ul>
813** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
814** opcode causes the xFileControl method to write the current state of
815** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
817** into an integer that the pArg argument points to. This capability
818** is used during testing and is only available when the SQLITE_TEST
819** compile-time option is used.
822** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
823** layer a hint of how large the database file will grow to be during the
824** current transaction. This hint is not guaranteed to be accurate but it
825** is often close. The underlying VFS might choose to preallocate database
826** file space based on this hint in order to help writes to the database
827** file run faster.
830** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that
831** implements [sqlite3_deserialize()] to set an upper bound on the size
832** of the in-memory database. The argument is a pointer to a [sqlite3_int64].
833** If the integer pointed to is negative, then it is filled in with the
834** current limit. Otherwise the limit is set to the larger of the value
835** of the integer pointed to and the current database size. The integer
836** pointed to is set to the new limit.
839** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
840** extends and truncates the database file in chunks of a size specified
841** by the user. The fourth argument to [sqlite3_file_control()] should
842** point to an integer (type int) containing the new chunk-size to use
843** for the nominated database. Allocating database file space in large
844** chunks (say 1MB at a time), may reduce file-system fragmentation and
845** improve performance on some systems.
848** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
849** to the [sqlite3_file] object associated with a particular database
850** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER].
853** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
854** to the [sqlite3_file] object associated with the journal file (either
855** the [rollback journal] or the [write-ahead log]) for a particular database
856** connection. See also [SQLITE_FCNTL_FILE_POINTER].
859** No longer in use.
861** <li>[[SQLITE_FCNTL_SYNC]]
862** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
863** sent to the VFS immediately before the xSync method is invoked on a
864** database file descriptor. Or, if the xSync method is not invoked
865** because the user has configured SQLite with
866** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
867** of the xSync method. In most cases, the pointer argument passed with
868** this file-control is NULL. However, if the database file is being synced
869** as part of a multi-database commit, the argument points to a nul-terminated
870** string containing the transactions master-journal file name. VFSes that
871** do not need this signal should silently ignore this opcode. Applications
872** should not call [sqlite3_file_control()] with this opcode as doing so may
873** disrupt the operation of the specialized VFSes that do require it.
876** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
877** and sent to the VFS after a transaction has been committed immediately
878** but before the database is unlocked. VFSes that do not need this signal
879** should silently ignore this opcode. Applications should not call
880** [sqlite3_file_control()] with this opcode as doing so may disrupt the
881** operation of the specialized VFSes that do require it.
884** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
885** retry counts and intervals for certain disk I/O operations for the
886** windows [VFS] in order to provide robustness in the presence of
887** anti-virus programs. By default, the windows VFS will retry file read,
888** file write, and file delete operations up to 10 times, with a delay
889** of 25 milliseconds before the first retry and with the delay increasing
890** by an additional 25 milliseconds with each subsequent retry. This
891** opcode allows these two values (10 retries and 25 milliseconds of delay)
892** to be adjusted. The values are changed for all database connections
893** within the same process. The argument is a pointer to an array of two
894** integers where the first integer is the new retry count and the second
895** integer is the delay. If either integer is negative, then the setting
896** is not changed but instead the prior value of that setting is written
897** into the array entry, allowing the current retry settings to be
898** interrogated. The zDbName parameter is ignored.
901** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
902** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
903** write ahead log ([WAL file]) and shared memory
904** files used for transaction control
905** are automatically deleted when the latest connection to the database
906** closes. Setting persistent WAL mode causes those files to persist after
907** close. Persisting the files is useful when other processes that do not
908** have write permission on the directory containing the database file want
909** to read the database file, as the WAL and shared memory files must exist
910** in order for the database to be readable. The fourth parameter to
911** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
912** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
913** WAL mode. If the integer is -1, then it is overwritten with the current
914** WAL persistence setting.
917** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
918** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
919** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
920** xDeviceCharacteristics methods. The fourth parameter to
921** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
922** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
923** mode. If the integer is -1, then it is overwritten with the current
924** zero-damage mode setting.
927** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
928** a write transaction to indicate that, unless it is rolled back for some
929** reason, the entire database file will be overwritten by the current
930** transaction. This is used by VACUUM operations.
933** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
934** all [VFSes] in the VFS stack. The names are of all VFS shims and the
935** final bottom-level VFS are written into memory obtained from
936** [sqlite3_malloc()] and the result is stored in the char* variable
937** that the fourth parameter of [sqlite3_file_control()] points to.
938** The caller is responsible for freeing the memory when done. As with
939** all file-control actions, there is no guarantee that this will actually
940** do anything. Callers should initialize the char* variable to a NULL
941** pointer in case this file-control is not implemented. This file-control
942** is intended for diagnostic use only.
945** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
946** [VFSes] currently in use. ^(The argument X in
947** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
948** of type "[sqlite3_vfs] **". This opcodes will set *X
949** to a pointer to the top-level VFS.)^
950** ^When there are multiple VFS shims in the stack, this opcode finds the
951** upper-most shim only.
954** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
955** file control is sent to the open [sqlite3_file] object corresponding
956** to the database file to which the pragma statement refers. ^The argument
957** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
958** pointers to strings (char**) in which the second element of the array
959** is the name of the pragma and the third element is the argument to the
960** pragma or NULL if the pragma has no argument. ^The handler for an
961** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
962** of the char** argument point to a string obtained from [sqlite3_mprintf()]
963** or the equivalent and that string will become the result of the pragma or
964** the error message if the pragma fails. ^If the
965** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
966** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
967** file control returns [SQLITE_OK], then the parser assumes that the
968** VFS has handled the PRAGMA itself and the parser generates a no-op
969** prepared statement if result string is NULL, or that returns a copy
970** of the result string if the string is non-NULL.
971** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
972** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
973** that the VFS encountered an error while handling the [PRAGMA] and the
974** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
975** file control occurs at the beginning of pragma statement analysis and so
976** it is able to override built-in [PRAGMA] statements.
980** file-control may be invoked by SQLite on the database file handle
981** shortly after it is opened in order to provide a custom VFS with access
982** to the connections busy-handler callback. The argument is of type (void **)
983** - an array of two (void *) values. The first (void *) actually points
984** to a function of type (int (*)(void *)). In order to invoke the connections
985** busy-handler, this function should be invoked with the second (void *) in
986** the array as the only argument. If it returns non-zero, then the operation
987** should be retried. If it returns zero, the custom VFS should abandon the
988** current operation.
991** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
992** to have SQLite generate a
993** temporary filename using the same algorithm that is followed to generate
994** temporary filenames for TEMP tables and other internal uses. The
995** argument should be a char** which will be filled with the filename
996** written into memory obtained from [sqlite3_malloc()]. The caller should
997** invoke [sqlite3_free()] on the result to avoid a memory leak.
1000** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
1001** maximum number of bytes that will be used for memory-mapped I/O.
1002** The argument is a pointer to a value of type sqlite3_int64 that
1003** is an advisory maximum number of bytes in the file to memory map. The
1004** pointer is overwritten with the old value. The limit is not changed if
1005** the value originally pointed to is negative, and so the current limit
1006** can be queried by passing in a pointer to a negative number. This
1007** file-control is used internally to implement [PRAGMA mmap_size].
1009** <li>[[SQLITE_FCNTL_TRACE]]
1010** The [SQLITE_FCNTL_TRACE] file control provides advisory information
1011** to the VFS about what the higher layers of the SQLite stack are doing.
1012** This file control is used by some VFS activity tracing [shims].
1013** The argument is a zero-terminated string. Higher layers in the
1014** SQLite stack may generate instances of this file control if
1015** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
1018** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
1019** pointer to an integer and it writes a boolean into that integer depending
1020** on whether or not the file has been renamed, moved, or deleted since it
1021** was first opened.
1024** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
1025** underlying native file handle associated with a file handle. This file
1026** control interprets its argument as a pointer to a native file handle and
1027** writes the resulting value there.
1030** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This
1031** opcode causes the xFileControl method to swap the file handle with the one
1032** pointed to by the pArg argument. This capability is used during testing
1033** and only needs to be supported when SQLITE_TEST is defined.
1036** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
1037** be advantageous to block on the next WAL lock if the lock is not immediately
1038** available. The WAL subsystem issues this signal during rare
1039** circumstances in order to fix a problem with priority inversion.
1040** Applications should <em>not</em> use this file-control.
1042** <li>[[SQLITE_FCNTL_ZIPVFS]]
1043** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
1044** VFS should return SQLITE_NOTFOUND for this opcode.
1046** <li>[[SQLITE_FCNTL_RBU]]
1047** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
1048** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for
1049** this opcode.
1052** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
1053** the file descriptor is placed in "batch write mode", which
1054** means all subsequent write operations will be deferred and done
1055** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems
1056** that do not support batch atomic writes will return SQLITE_NOTFOUND.
1057** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
1058** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
1060** no VFS interface calls on the same [sqlite3_file] file descriptor
1061** except for calls to the xWrite method and the xFileControl method
1065** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
1066** operations since the previous successful call to
1067** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
1068** This file control returns [SQLITE_OK] if and only if the writes were
1069** all performed successfully and have been committed to persistent storage.
1070** ^Regardless of whether or not it is successful, this file control takes
1071** the file descriptor out of batch write mode so that all subsequent
1072** write operations are independent.
1073** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
1074** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1077** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
1078** operations since the previous successful call to
1079** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
1080** ^This file control takes the file descriptor out of batch write mode
1081** so that all subsequent write operations are independent.
1082** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
1083** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1086** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode causes attempts to obtain
1087** a file lock using the xLock or xShmLock methods of the VFS to wait
1088** for up to M milliseconds before failing, where M is the single
1089** unsigned integer parameter.
1092** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
1093** a database file. The argument is a pointer to a 32-bit unsigned integer.
1094** The "data version" for the pager is written into the pointer. The
1095** "data version" changes whenever any change occurs to the corresponding
1096** database file, either through SQL statements on the same database
1097** connection or through transactions committed by separate database
1098** connections possibly in other processes. The [sqlite3_total_changes()]
1099** interface can be used to find if any database on the connection has changed,
1100** but that interface responds to changes on TEMP as well as MAIN and does
1101** not provide a mechanism to detect changes to MAIN only. Also, the
1102** [sqlite3_total_changes()] interface responds to internal changes only and
1103** omits changes made by other database connections. The
1104** [PRAGMA data_version] command provide a mechanism to detect changes to
1105** a single attached database that occur due to other database connections,
1106** but omits changes implemented by the database connection on which it is
1107** called. This file control is the only mechanism to detect changes that
1108** happen either internally or externally and that are associated with
1109** a particular attached database.
1110** </ul>
1125#define SQLITE_FCNTL_PRAGMA 14
1129#define SQLITE_FCNTL_TRACE 19
1131#define SQLITE_FCNTL_SYNC 21
1135#define SQLITE_FCNTL_ZIPVFS 25
1136#define SQLITE_FCNTL_RBU 26
1140#define SQLITE_FCNTL_PDB 30
1148/* deprecated names */
1155** CAPI3REF: Mutex Handle
1157** The mutex module within SQLite defines [sqlite3_mutex] to be an
1158** abstract type for a mutex object. The SQLite core never looks
1159** at the internal representation of an [sqlite3_mutex]. It only
1160** deals with pointers to the [sqlite3_mutex] object.
1162** Mutexes are created using [sqlite3_mutex_alloc()].
1164typedef struct sqlite3_mutex sqlite3_mutex;
1167** CAPI3REF: Loadable Extension Thunk
1169** A pointer to the opaque sqlite3_api_routines structure is passed as
1170** the third parameter to entry points of [loadable extensions]. This
1171** structure must be typedefed in order to work around compiler warnings
1172** on some platforms.
1174typedef struct sqlite3_api_routines sqlite3_api_routines;
1177** CAPI3REF: OS Interface Object
1179** An instance of the sqlite3_vfs object defines the interface between
1180** the SQLite core and the underlying operating system. The "vfs"
1181** in the name of the object stands for "virtual file system". See
1182** the [VFS | VFS documentation] for further information.
1184** The VFS interface is sometimes extended by adding new methods onto
1185** the end. Each time such an extension occurs, the iVersion field
1186** is incremented. The iVersion value started out as 1 in
1187** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
1188** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
1189** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields
1190** may be appended to the sqlite3_vfs object and the iVersion value
1191** may increase again in future versions of SQLite.
1192** Note that the structure
1193** of the sqlite3_vfs object changes in the transition from
1194** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
1195** and yet the iVersion field was not modified.
1197** The szOsFile field is the size of the subclassed [sqlite3_file]
1198** structure used by this VFS. mxPathname is the maximum length of
1199** a pathname in this VFS.
1201** Registered sqlite3_vfs objects are kept on a linked list formed by
1202** the pNext pointer. The [sqlite3_vfs_register()]
1203** and [sqlite3_vfs_unregister()] interfaces manage this list
1204** in a thread-safe way. The [sqlite3_vfs_find()] interface
1205** searches the list. Neither the application code nor the VFS
1206** implementation should use the pNext pointer.
1208** The pNext field is the only field in the sqlite3_vfs
1209** structure that SQLite will ever modify. SQLite will only access
1210** or modify this field while holding a particular static mutex.
1211** The application should never modify anything within the sqlite3_vfs
1212** object once the object has been registered.
1214** The zName field holds the name of the VFS module. The name must
1215** be unique across all VFS modules.
1217** [[sqlite3_vfs.xOpen]]
1218** ^SQLite guarantees that the zFilename parameter to xOpen
1219** is either a NULL pointer or string obtained
1220** from xFullPathname() with an optional suffix added.
1221** ^If a suffix is added to the zFilename parameter, it will
1222** consist of a single "-" character followed by no more than
1223** 11 alphanumeric and/or "-" characters.
1224** ^SQLite further guarantees that
1225** the string will be valid and unchanged until xClose() is
1226** called. Because of the previous sentence,
1227** the [sqlite3_file] can safely store a pointer to the
1228** filename if it needs to remember the filename for some reason.
1229** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1230** must invent its own temporary name for the file. ^Whenever the
1231** xFilename parameter is NULL it will also be the case that the
1232** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1234** The flags argument to xOpen() includes all bits set in
1235** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
1236** or [sqlite3_open16()] is used, then flags includes at least
1238** If xOpen() opens a file read-only then it sets *pOutFlags to
1239** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
1241** ^(SQLite will also add one of the following flags to the xOpen()
1242** call, depending on the object being opened:
1244** <ul>
1245** <li> [SQLITE_OPEN_MAIN_DB]
1247** <li> [SQLITE_OPEN_TEMP_DB]
1252** <li> [SQLITE_OPEN_WAL]
1253** </ul>)^
1255** The file I/O implementation can use the object type flags to
1256** change the way it deals with files. For example, an application
1257** that does not care about crash recovery or rollback might make
1258** the open of a journal file a no-op. Writes to this journal would
1259** also be no-ops, and any attempt to read the journal would return
1260** SQLITE_IOERR. Or the implementation might recognize that a database
1261** file will be doing page-aligned sector reads and writes in a random
1262** order and set up its I/O subsystem accordingly.
1264** SQLite might also add one of the following flags to the xOpen method:
1266** <ul>
1269** </ul>
1271** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1272** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1273** will be set for TEMP databases and their journals, transient
1274** databases, and subjournals.
1276** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1277** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1278** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1279** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1280** SQLITE_OPEN_CREATE, is used to indicate that file should always
1281** be created, and that it is an error if it already exists.
1282** It is <i>not</i> used to indicate the file should be opened
1283** for exclusive access.
1285** ^At least szOsFile bytes of memory are allocated by SQLite
1286** to hold the [sqlite3_file] structure passed as the third
1287** argument to xOpen. The xOpen method does not have to
1288** allocate the structure; it should just fill it in. Note that
1289** the xOpen method must set the sqlite3_file.pMethods to either
1290** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1291** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1292** element will be valid after xOpen returns regardless of the success
1293** or failure of the xOpen call.
1295** [[sqlite3_vfs.xAccess]]
1296** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1297** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1298** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1299** to test whether a file is at least readable. The file can be a
1300** directory.
1302** ^SQLite will always allocate at least mxPathname+1 bytes for the
1303** output buffer xFullPathname. The exact size of the output buffer
1304** is also passed as a parameter to both methods. If the output buffer
1305** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1306** handled as a fatal error by SQLite, vfs implementations should endeavor
1307** to prevent this by setting mxPathname to a sufficiently large value.
1309** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1310** interfaces are not strictly a part of the filesystem, but they are
1311** included in the VFS structure for completeness.
1312** The xRandomness() function attempts to return nBytes bytes
1313** of good-quality randomness into zOut. The return value is
1314** the actual number of bytes of randomness obtained.
1315** The xSleep() method causes the calling thread to sleep for at
1316** least the number of microseconds given. ^The xCurrentTime()
1317** method returns a Julian Day Number for the current date and time as
1318** a floating point value.
1319** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1320** Day Number multiplied by 86400000 (the number of milliseconds in
1321** a 24-hour day).
1322** ^SQLite will use the xCurrentTimeInt64() method to get the current
1323** date and time if that method is available (if iVersion is 2 or
1324** greater and the function pointer is not NULL) and will fall back
1325** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1327** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1328** are not used by the SQLite core. These optional interfaces are provided
1329** by some VFSes to facilitate testing of the VFS code. By overriding
1330** system calls with functions under its control, a test program can
1331** simulate faults and error conditions that would otherwise be difficult
1332** or impossible to induce. The set of system calls that can be overridden
1333** varies from one VFS to another, and from one version of the same VFS to the
1334** next. Applications that use these interfaces must be prepared for any
1335** or all of these interfaces to be NULL or for their behavior to change
1336** from one release to the next. Applications must not attempt to access
1337** any of these methods if the iVersion of the VFS is less than 3.
1339typedef struct sqlite3_vfs sqlite3_vfs;
1340typedef void (*sqlite3_syscall_ptr)(void);
1341struct sqlite3_vfs {
1342 int iVersion; /* Structure version number (currently 3) */
1343 int szOsFile; /* Size of subclassed sqlite3_file */
1344 int mxPathname; /* Maximum file pathname length */
1345 sqlite3_vfs *pNext; /* Next registered VFS */
1346 const char *zName; /* Name of this virtual file system */
1347 void *pAppData; /* Pointer to application-specific data */
1348 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1349 int flags, int *pOutFlags);
1350 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1351 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1352 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1353 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1354 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1355 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1356 void (*xDlClose)(sqlite3_vfs*, void*);
1357 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1358 int (*xSleep)(sqlite3_vfs*, int microseconds);
1359 int (*xCurrentTime)(sqlite3_vfs*, double*);
1360 int (*xGetLastError)(sqlite3_vfs*, int, char *);
1361 /*
1362 ** The methods above are in version 1 of the sqlite_vfs object
1363 ** definition. Those that follow are added in version 2 or later
1364 */
1365 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1366 /*
1367 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1368 ** Those below are for version 3 and greater.
1369 */
1370 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1371 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1372 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1373 /*
1374 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1375 ** New fields may be appended in future versions. The iVersion
1376 ** value will increment whenever this happens.
1377 */
1381** CAPI3REF: Flags for the xAccess VFS method
1383** These integer constants can be used as the third parameter to
1384** the xAccess method of an [sqlite3_vfs] object. They determine
1385** what kind of permissions the xAccess method is looking for.
1386** With SQLITE_ACCESS_EXISTS, the xAccess method
1387** simply checks whether the file exists.
1388** With SQLITE_ACCESS_READWRITE, the xAccess method
1389** checks whether the named directory is both readable and writable
1390** (in other words, if files can be added, removed, and renamed within
1391** the directory).
1392** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1393** [temp_store_directory pragma], though this could change in a future
1394** release of SQLite.
1395** With SQLITE_ACCESS_READ, the xAccess method
1396** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1397** currently unused, though it might be used in a future release of
1398** SQLite.
1401#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1402#define SQLITE_ACCESS_READ 2 /* Unused */
1405** CAPI3REF: Flags for the xShmLock VFS method
1407** These integer constants define the various locking operations
1408** allowed by the xShmLock method of [sqlite3_io_methods]. The
1409** following are the only legal combinations of flags to the
1410** xShmLock method:
1412** <ul>
1417** </ul>
1419** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1420** was given on the corresponding lock.
1422** The xShmLock method can transition between unlocked and SHARED or
1423** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1424** and EXCLUSIVE.
1426#define SQLITE_SHM_UNLOCK 1
1427#define SQLITE_SHM_LOCK 2
1428#define SQLITE_SHM_SHARED 4
1432** CAPI3REF: Maximum xShmLock index
1434** The xShmLock method on [sqlite3_io_methods] may use values
1435** between 0 and this upper bound as its "offset" argument.
1436** The SQLite core will never attempt to acquire or release a
1437** lock outside of this range
1439#define SQLITE_SHM_NLOCK 8
1443** CAPI3REF: Initialize The SQLite Library
1445** ^The sqlite3_initialize() routine initializes the
1446** SQLite library. ^The sqlite3_shutdown() routine
1447** deallocates any resources that were allocated by sqlite3_initialize().
1448** These routines are designed to aid in process initialization and
1449** shutdown on embedded systems. Workstation applications using
1450** SQLite normally do not need to invoke either of these routines.
1452** A call to sqlite3_initialize() is an "effective" call if it is
1453** the first time sqlite3_initialize() is invoked during the lifetime of
1454** the process, or if it is the first time sqlite3_initialize() is invoked
1455** following a call to sqlite3_shutdown(). ^(Only an effective call
1456** of sqlite3_initialize() does any initialization. All other calls
1457** are harmless no-ops.)^
1459** A call to sqlite3_shutdown() is an "effective" call if it is the first
1460** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1461** an effective call to sqlite3_shutdown() does any deinitialization.
1462** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1464** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1465** is not. The sqlite3_shutdown() interface must only be called from a
1466** single thread. All open [database connections] must be closed and all
1467** other SQLite resources must be deallocated prior to invoking
1468** sqlite3_shutdown().
1470** Among other things, ^sqlite3_initialize() will invoke
1471** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1472** will invoke sqlite3_os_end().
1474** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1475** ^If for some reason, sqlite3_initialize() is unable to initialize
1476** the library (perhaps it is unable to allocate a needed resource such
1477** as a mutex) it returns an [error code] other than [SQLITE_OK].
1479** ^The sqlite3_initialize() routine is called internally by many other
1480** SQLite interfaces so that an application usually does not need to
1481** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1482** calls sqlite3_initialize() so the SQLite library will be automatically
1483** initialized when [sqlite3_open()] is called if it has not be initialized
1484** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1485** compile-time option, then the automatic calls to sqlite3_initialize()
1486** are omitted and the application must call sqlite3_initialize() directly
1487** prior to using any other SQLite interface. For maximum portability,
1488** it is recommended that applications always invoke sqlite3_initialize()
1489** directly prior to using any other SQLite interface. Future releases
1490** of SQLite may require this. In other words, the behavior exhibited
1491** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1492** default behavior in some future release of SQLite.
1494** The sqlite3_os_init() routine does operating-system specific
1495** initialization of the SQLite library. The sqlite3_os_end()
1496** routine undoes the effect of sqlite3_os_init(). Typical tasks
1497** performed by these routines include allocation or deallocation
1498** of static resources, initialization of global variables,
1499** setting up a default [sqlite3_vfs] module, or setting up
1500** a default configuration using [sqlite3_config()].
1502** The application should never invoke either sqlite3_os_init()
1503** or sqlite3_os_end() directly. The application should only invoke
1504** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1505** interface is called automatically by sqlite3_initialize() and
1506** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1507** implementations for sqlite3_os_init() and sqlite3_os_end()
1508** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1509** When [custom builds | built for other platforms]
1510** (using the [SQLITE_OS_OTHER=1] compile-time
1511** option) the application must supply a suitable implementation for
1512** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1513** implementation of sqlite3_os_init() or sqlite3_os_end()
1514** must return [SQLITE_OK] on success and some other [error code] upon
1515** failure.
1517SQLITE_API int sqlite3_initialize(void);
1518SQLITE_API int sqlite3_shutdown(void);
1519SQLITE_API int sqlite3_os_init(void);
1520SQLITE_API int sqlite3_os_end(void);
1523** CAPI3REF: Configuring The SQLite Library
1525** The sqlite3_config() interface is used to make global configuration
1526** changes to SQLite in order to tune SQLite to the specific needs of
1527** the application. The default configuration is recommended for most
1528** applications and so this routine is usually not necessary. It is
1529** provided to support rare applications with unusual needs.
1531** <b>The sqlite3_config() interface is not threadsafe. The application
1532** must ensure that no other SQLite interfaces are invoked by other
1533** threads while sqlite3_config() is running.</b>
1535** The sqlite3_config() interface
1536** may only be invoked prior to library initialization using
1537** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1538** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1539** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1540** Note, however, that ^sqlite3_config() can be called as part of the
1541** implementation of an application-defined [sqlite3_os_init()].
1543** The first argument to sqlite3_config() is an integer
1544** [configuration option] that determines
1545** what property of SQLite is to be configured. Subsequent arguments
1546** vary depending on the [configuration option]
1547** in the first argument.
1549** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1550** ^If the option is unknown or SQLite is unable to set the option
1551** then this routine returns a non-zero [error code].
1553SQLITE_API int sqlite3_config(int, ...);
1556** CAPI3REF: Configure database connections
1557** METHOD: sqlite3
1559** The sqlite3_db_config() interface is used to make configuration
1560** changes to a [database connection]. The interface is similar to
1561** [sqlite3_config()] except that the changes apply to a single
1562** [database connection] (specified in the first argument).
1564** The second argument to sqlite3_db_config(D,V,...) is the
1565** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1566** that indicates what aspect of the [database connection] is being configured.
1567** Subsequent arguments vary depending on the configuration verb.
1569** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1570** the call is considered successful.
1572SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1575** CAPI3REF: Memory Allocation Routines
1577** An instance of this object defines the interface between SQLite
1578** and low-level memory allocation routines.
1580** This object is used in only one place in the SQLite interface.
1581** A pointer to an instance of this object is the argument to
1582** [sqlite3_config()] when the configuration option is
1584** By creating an instance of this object
1585** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1586** during configuration, an application can specify an alternative
1587** memory allocation subsystem for SQLite to use for all of its
1588** dynamic memory needs.
1590** Note that SQLite comes with several [built-in memory allocators]
1591** that are perfectly adequate for the overwhelming majority of applications
1592** and that this object is only useful to a tiny minority of applications
1593** with specialized memory allocation requirements. This object is
1594** also used during testing of SQLite in order to specify an alternative
1595** memory allocator that simulates memory out-of-memory conditions in
1596** order to verify that SQLite recovers gracefully from such
1597** conditions.
1599** The xMalloc, xRealloc, and xFree methods must work like the
1600** malloc(), realloc() and free() functions from the standard C library.
1601** ^SQLite guarantees that the second argument to
1602** xRealloc is always a value returned by a prior call to xRoundup.
1604** xSize should return the allocated size of a memory allocation
1605** previously obtained from xMalloc or xRealloc. The allocated size
1606** is always at least as big as the requested size but may be larger.
1608** The xRoundup method returns what would be the allocated size of
1609** a memory allocation given a particular requested size. Most memory
1610** allocators round up memory allocations at least to the next multiple
1611** of 8. Some allocators round up to a larger multiple or to a power of 2.
1612** Every memory allocation request coming in through [sqlite3_malloc()]
1613** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1614** that causes the corresponding memory allocation to fail.
1616** The xInit method initializes the memory allocator. For example,
1617** it might allocate any require mutexes or initialize internal data
1618** structures. The xShutdown method is invoked (indirectly) by
1619** [sqlite3_shutdown()] and should deallocate any resources acquired
1620** by xInit. The pAppData pointer is used as the only parameter to
1621** xInit and xShutdown.
1623** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1624** the xInit method, so the xInit method need not be threadsafe. The
1625** xShutdown method is only called from [sqlite3_shutdown()] so it does
1626** not need to be threadsafe either. For all other methods, SQLite
1627** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1628** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1629** it is by default) and so the methods are automatically serialized.
1630** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1631** methods must be threadsafe or else make their own arrangements for
1632** serialization.
1634** SQLite will never invoke xInit() more than once without an intervening
1635** call to xShutdown().
1637typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1638struct sqlite3_mem_methods {
1639 void *(*xMalloc)(int); /* Memory allocation function */
1640 void (*xFree)(void*); /* Free a prior allocation */
1641 void *(*xRealloc)(void*,int); /* Resize an allocation */
1642 int (*xSize)(void*); /* Return the size of an allocation */
1643 int (*xRoundup)(int); /* Round up request size to allocation size */
1644 int (*xInit)(void*); /* Initialize the memory allocator */
1645 void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1646 void *pAppData; /* Argument to xInit() and xShutdown() */
1650** CAPI3REF: Configuration Options
1651** KEYWORDS: {configuration option}
1653** These constants are the available integer configuration options that
1654** can be passed as the first argument to the [sqlite3_config()] interface.
1656** New configuration options may be added in future releases of SQLite.
1657** Existing configuration options might be discontinued. Applications
1658** should check the return code from [sqlite3_config()] to make sure that
1659** the call worked. The [sqlite3_config()] interface will return a
1660** non-zero [error code] if a discontinued or unsupported configuration option
1661** is invoked.
1663** <dl>
1665** <dd>There are no arguments to this option. ^This option sets the
1666** [threading mode] to Single-thread. In other words, it disables
1667** all mutexing and puts SQLite into a mode where it can only be used
1668** by a single thread. ^If SQLite is compiled with
1669** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1670** it is not possible to change the [threading mode] from its default
1671** value of Single-thread and so [sqlite3_config()] will return
1673** configuration option.</dd>
1676** <dd>There are no arguments to this option. ^This option sets the
1677** [threading mode] to Multi-thread. In other words, it disables
1678** mutexing on [database connection] and [prepared statement] objects.
1679** The application is responsible for serializing access to
1680** [database connections] and [prepared statements]. But other mutexes
1681** are enabled so that SQLite will be safe to use in a multi-threaded
1682** environment as long as no two threads attempt to use the same
1683** [database connection] at the same time. ^If SQLite is compiled with
1684** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1685** it is not possible to set the Multi-thread [threading mode] and
1686** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1687** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1690** <dd>There are no arguments to this option. ^This option sets the
1691** [threading mode] to Serialized. In other words, this option enables
1692** all mutexes including the recursive
1693** mutexes on [database connection] and [prepared statement] objects.
1694** In this mode (which is the default when SQLite is compiled with
1695** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1696** to [database connections] and [prepared statements] so that the
1697** application is free to use the same [database connection] or the
1698** same [prepared statement] in different threads at the same time.
1699** ^If SQLite is compiled with
1700** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1701** it is not possible to set the Serialized [threading mode] and
1702** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1703** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1706** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1707** a pointer to an instance of the [sqlite3_mem_methods] structure.
1708** The argument specifies
1709** alternative low-level memory allocation routines to be used in place of
1710** the memory allocation routines built into SQLite.)^ ^SQLite makes
1711** its own private copy of the content of the [sqlite3_mem_methods] structure
1712** before the [sqlite3_config()] call returns.</dd>
1715** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1716** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1717** The [sqlite3_mem_methods]
1718** structure is filled with the currently defined memory allocation routines.)^
1719** This option can be used to overload the default memory allocation
1720** routines with a wrapper that simulations memory allocation failure or
1721** tracks memory usage, for example. </dd>
1724** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
1725** type int, interpreted as a boolean, which if true provides a hint to
1726** SQLite that it should avoid large memory allocations if possible.
1727** SQLite will run faster if it is free to make large memory allocations,
1728** but some application might prefer to run slower in exchange for
1729** guarantees about memory fragmentation that are possible if large
1730** allocations are avoided. This hint is normally off.
1731** </dd>
1734** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1735** interpreted as a boolean, which enables or disables the collection of
1736** memory allocation statistics. ^(When memory allocation statistics are
1737** disabled, the following SQLite interfaces become non-operational:
1738** <ul>
1739** <li> [sqlite3_memory_used()]
1740** <li> [sqlite3_memory_highwater()]
1741** <li> [sqlite3_soft_heap_limit64()]
1742** <li> [sqlite3_status64()]
1743** </ul>)^
1744** ^Memory allocation statistics are enabled by default unless SQLite is
1745** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1746** allocation statistics are disabled by default.
1747** </dd>
1750** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
1751** </dd>
1754** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
1755** that SQLite can use for the database page cache with the default page
1756** cache implementation.
1757** This configuration option is a no-op if an application-define page
1758** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
1759** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1760** 8-byte aligned memory (pMem), the size of each page cache line (sz),
1761** and the number of cache lines (N).
1762** The sz argument should be the size of the largest database page
1763** (a power of two between 512 and 65536) plus some extra bytes for each
1764** page header. ^The number of extra bytes needed by the page header
1765** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
1766** ^It is harmless, apart from the wasted memory,
1767** for the sz parameter to be larger than necessary. The pMem
1768** argument must be either a NULL pointer or a pointer to an 8-byte
1769** aligned block of memory of at least sz*N bytes, otherwise
1770** subsequent behavior is undefined.
1771** ^When pMem is not NULL, SQLite will strive to use the memory provided
1772** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
1773** a page cache line is larger than sz bytes or if all of the pMem buffer
1774** is exhausted.
1775** ^If pMem is NULL and N is non-zero, then each database connection
1776** does an initial bulk allocation for page cache memory
1777** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
1778** of -1024*N bytes if N is negative, . ^If additional
1779** page cache memory is needed beyond what is provided by the initial
1780** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
1781** additional cache line. </dd>
1784** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1785** that SQLite will use for all of its dynamic memory allocation needs
1786** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
1787** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1788** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1789** [SQLITE_ERROR] if invoked otherwise.
1790** ^There are three arguments to SQLITE_CONFIG_HEAP:
1791** An 8-byte aligned pointer to the memory,
1792** the number of bytes in the memory buffer, and the minimum allocation size.
1793** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1794** to using its default memory allocator (the system malloc() implementation),
1795** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1796** memory pointer is not NULL then the alternative memory
1797** allocator is engaged to handle all of SQLites memory allocation needs.
1798** The first pointer (the memory pointer) must be aligned to an 8-byte
1799** boundary or subsequent behavior of SQLite will be undefined.
1800** The minimum allocation size is capped at 2**12. Reasonable values
1801** for the minimum allocation size are 2**5 through 2**8.</dd>
1804** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1805** pointer to an instance of the [sqlite3_mutex_methods] structure.
1806** The argument specifies alternative low-level mutex routines to be used
1807** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of
1808** the content of the [sqlite3_mutex_methods] structure before the call to
1809** [sqlite3_config()] returns. ^If SQLite is compiled with
1810** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1811** the entire mutexing subsystem is omitted from the build and hence calls to
1812** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1813** return [SQLITE_ERROR].</dd>
1816** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1817** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The
1818** [sqlite3_mutex_methods]
1819** structure is filled with the currently defined mutex routines.)^
1820** This option can be used to overload the default mutex allocation
1821** routines with a wrapper used to track mutex usage for performance
1822** profiling or testing, for example. ^If SQLite is compiled with
1823** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1824** the entire mutexing subsystem is omitted from the build and hence calls to
1825** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1826** return [SQLITE_ERROR].</dd>
1829** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1830** the default size of lookaside memory on each [database connection].
1831** The first argument is the
1832** size of each lookaside buffer slot and the second is the number of
1833** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE
1834** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1835** option to [sqlite3_db_config()] can be used to change the lookaside
1836** configuration on individual connections.)^ </dd>
1839** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1840** a pointer to an [sqlite3_pcache_methods2] object. This object specifies
1841** the interface to a custom page cache implementation.)^
1842** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1845** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1846** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of
1847** the current page cache implementation into that object.)^ </dd>
1850** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1851** global [error log].
1852** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1853** function with a call signature of void(*)(void*,int,const char*),
1854** and a pointer to void. ^If the function pointer is not NULL, it is
1855** invoked by [sqlite3_log()] to process each logging event. ^If the
1856** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1857** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1858** passed through as the first parameter to the application-defined logger
1859** function whenever that function is invoked. ^The second parameter to
1860** the logger function is a copy of the first parameter to the corresponding
1861** [sqlite3_log()] call and is intended to be a [result code] or an
1862** [extended result code]. ^The third parameter passed to the logger is
1863** log message after formatting via [sqlite3_snprintf()].
1864** The SQLite logging interface is not reentrant; the logger function
1865** supplied by the application must not invoke any SQLite interface.
1866** In a multi-threaded application, the application-defined logger
1867** function must be threadsafe. </dd>
1870** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1871** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1872** then URI handling is globally disabled.)^ ^If URI handling is globally
1873** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1874** [sqlite3_open16()] or
1875** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1876** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1877** connection is opened. ^If it is globally disabled, filenames are
1878** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1879** database connection is opened. ^(By default, URI handling is globally
1880** disabled. The default value may be changed by compiling with the
1881** [SQLITE_USE_URI] symbol defined.)^
1884** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1885** argument which is interpreted as a boolean in order to enable or disable
1886** the use of covering indices for full table scans in the query optimizer.
1887** ^The default setting is determined
1888** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1889** if that compile-time option is omitted.
1890** The ability to disable the use of covering indices for full table scans
1891** is because some incorrectly coded legacy applications might malfunction
1892** when the optimization is enabled. Providing the ability to
1893** disable the optimization allows the older, buggy application code to work
1894** without change even with newer versions of SQLite.
1898** <dd> These options are obsolete and should not be used by new code.
1899** They are retained for backwards compatibility but are now no-ops.
1900** </dd>
1904** <dd>This option is only available if sqlite is compiled with the
1905** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1906** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1907** The second should be of type (void*). The callback is invoked by the library
1908** in three separate circumstances, identified by the value passed as the
1909** fourth parameter. If the fourth parameter is 0, then the database connection
1910** passed as the second argument has just been opened. The third argument
1911** points to a buffer containing the name of the main database file. If the
1912** fourth parameter is 1, then the SQL statement that the third parameter
1913** points to has just been executed. Or, if the fourth parameter is 2, then
1914** the connection being passed as the second parameter is being closed. The
1915** third parameter is passed NULL In this case. An example of using this
1916** configuration option can be seen in the "test_sqllog.c" source file in
1917** the canonical SQLite source tree.</dd>
1921** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1922** that are the default mmap size limit (the default setting for
1923** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1924** ^The default setting can be overridden by each database connection using
1925** either the [PRAGMA mmap_size] command, or by using the
1926** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size
1927** will be silently truncated if necessary so that it does not exceed the
1928** compile-time maximum mmap size set by the
1929** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1930** ^If either argument to this option is negative, then that argument is
1931** changed to its compile-time default.
1935** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
1936** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
1937** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1938** that specifies the maximum size of the created heap.
1942** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
1943** is a pointer to an integer and writes into that integer the number of extra
1944** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
1945** The amount of extra space required can change depending on the compiler,
1946** target platform, and SQLite version.
1950** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
1951** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
1952** sorter to that integer. The default minimum PMA Size is set by the
1953** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched
1954** to help with sort operations when multithreaded sorting
1955** is enabled (using the [PRAGMA threads] command) and the amount of content
1956** to be sorted exceeds the page size times the minimum of the
1957** [PRAGMA cache_size] setting and this value.
1961** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
1962** becomes the [statement journal] spill-to-disk threshold.
1963** [Statement journals] are held in memory until their size (in bytes)
1964** exceeds this threshold, at which point they are written to disk.
1965** Or if the threshold is -1, statement journals are always held
1966** exclusively in memory.
1967** Since many statement journals never become large, setting the spill
1968** threshold to a value such as 64KiB can greatly reduce the amount of
1969** I/O required to support statement rollback.
1970** The default value for this setting is controlled by the
1971** [SQLITE_STMTJRNL_SPILL] compile-time option.
1975** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
1976** of type (int) - the new value of the sorter-reference size threshold.
1977** Usually, when SQLite uses an external sort to order records according
1978** to an ORDER BY clause, all fields required by the caller are present in the
1979** sorted records. However, if SQLite determines based on the declared type
1980** of a table column that its values are likely to be very large - larger
1981** than the configured sorter-reference size threshold - then a reference
1982** is stored in each sorted record and the required column values loaded
1983** from the database as records are returned in sorted order. The default
1984** value for this option is to never use this optimization. Specifying a
1985** negative value for this option restores the default behaviour.
1986** This option is only available if SQLite is compiled with the
1987** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
1991** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
1992** [sqlite3_int64] parameter which is the default maximum size for an in-memory
1993** database created using [sqlite3_deserialize()]. This default maximum
1994** size can be adjusted up or down for individual databases using the
1995** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control]. If this
1996** configuration setting is never used, then the default maximum is determined
1997** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option. If that
1998** compile-time option is not set, then the default maximum is 1073741824.
1999** </dl>
2001#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
2002#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
2003#define SQLITE_CONFIG_SERIALIZED 3 /* nil */
2004#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
2005#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
2006#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */
2007#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
2008#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
2009#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
2010#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
2011#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
2012/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
2013#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
2014#define SQLITE_CONFIG_PCACHE 14 /* no-op */
2015#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
2016#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
2017#define SQLITE_CONFIG_URI 17 /* int */
2018#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
2019#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
2020#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
2021#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
2022#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
2023#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
2024#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */
2025#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */
2026#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */
2027#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */
2028#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */
2029#define SQLITE_CONFIG_MEMDB_MAXSIZE 29 /* sqlite3_int64 */
2032** CAPI3REF: Database Connection Configuration Options
2034** These constants are the available integer configuration options that
2035** can be passed as the second argument to the [sqlite3_db_config()] interface.
2037** New configuration options may be added in future releases of SQLite.
2038** Existing configuration options might be discontinued. Applications
2039** should check the return code from [sqlite3_db_config()] to make sure that
2040** the call worked. ^The [sqlite3_db_config()] interface will return a
2041** non-zero [error code] if a discontinued or unsupported configuration option
2042** is invoked.
2044** <dl>
2047** <dd> ^This option takes three additional arguments that determine the
2048** [lookaside memory allocator] configuration for the [database connection].
2049** ^The first argument (the third parameter to [sqlite3_db_config()] is a
2050** pointer to a memory buffer to use for lookaside memory.
2051** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
2052** may be NULL in which case SQLite will allocate the
2053** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
2054** size of each lookaside buffer slot. ^The third argument is the number of
2055** slots. The size of the buffer in the first argument must be greater than
2056** or equal to the product of the second and third arguments. The buffer
2057** must be aligned to an 8-byte boundary. ^If the second argument to
2058** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
2059** rounded down to the next smaller multiple of 8. ^(The lookaside memory
2060** configuration for a database connection can only be changed when that
2061** connection is not currently using lookaside memory, or in other words
2062** when the "current value" returned by
2063** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
2064** Any attempt to change the lookaside memory configuration when lookaside
2065** memory is in use leaves the configuration unchanged and returns
2066** [SQLITE_BUSY].)^</dd>
2070** <dd> ^This option is used to enable or disable the enforcement of
2071** [foreign key constraints]. There should be two additional arguments.
2072** The first argument is an integer which is 0 to disable FK enforcement,
2073** positive to enable FK enforcement or negative to leave FK enforcement
2074** unchanged. The second parameter is a pointer to an integer into which
2075** is written 0 or 1 to indicate whether FK enforcement is off or on
2076** following this call. The second parameter may be a NULL pointer, in
2077** which case the FK enforcement setting is not reported back. </dd>
2081** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
2082** There should be two additional arguments.
2083** The first argument is an integer which is 0 to disable triggers,
2084** positive to enable triggers or negative to leave the setting unchanged.
2085** The second parameter is a pointer to an integer into which
2086** is written 0 or 1 to indicate whether triggers are disabled or enabled
2087** following this call. The second parameter may be a NULL pointer, in
2088** which case the trigger setting is not reported back. </dd>
2092** <dd> ^This option is used to enable or disable the
2093** [fts3_tokenizer()] function which is part of the
2094** [FTS3] full-text search engine extension.
2095** There should be two additional arguments.
2096** The first argument is an integer which is 0 to disable fts3_tokenizer() or
2097** positive to enable fts3_tokenizer() or negative to leave the setting
2098** unchanged.
2099** The second parameter is a pointer to an integer into which
2100** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
2101** following this call. The second parameter may be a NULL pointer, in
2102** which case the new setting is not reported back. </dd>
2106** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
2107** interface independently of the [load_extension()] SQL function.
2108** The [sqlite3_enable_load_extension()] API enables or disables both the
2109** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
2110** There should be two additional arguments.
2111** When the first argument to this interface is 1, then only the C-API is
2112** enabled and the SQL function remains disabled. If the first argument to
2113** this interface is 0, then both the C-API and the SQL function are disabled.
2114** If the first argument is -1, then no changes are made to state of either the
2115** C-API or the SQL function.
2116** The second parameter is a pointer to an integer into which
2117** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
2118** is disabled or enabled following this call. The second parameter may
2119** be a NULL pointer, in which case the new setting is not reported back.
2120** </dd>
2123** <dd> ^This option is used to change the name of the "main" database
2124** schema. ^The sole argument is a pointer to a constant UTF8 string
2125** which will become the new schema name in place of "main". ^SQLite
2126** does not make a copy of the new main schema name string, so the application
2127** must ensure that the argument passed into this DBCONFIG option is unchanged
2128** until after the database connection closes.
2129** </dd>
2133** <dd> Usually, when a database in wal mode is closed or detached from a
2134** database handle, SQLite checks if this will mean that there are now no
2135** connections at all to the database. If so, it performs a checkpoint
2136** operation before closing the connection. This option may be used to
2137** override this behaviour. The first parameter passed to this operation
2138** is an integer - positive to disable checkpoints-on-close, or zero (the
2139** default) to enable them, and negative to leave the setting unchanged.
2140** The second parameter is a pointer to an integer
2141** into which is written 0 or 1 to indicate whether checkpoints-on-close
2142** have been disabled - 0 if they are not disabled, 1 if they are.
2143** </dd>
2146** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
2147** the [query planner stability guarantee] (QPSG). When the QPSG is active,
2148** a single SQL query statement will always use the same algorithm regardless
2149** of values of [bound parameters].)^ The QPSG disables some query optimizations
2150** that look at the values of bound parameters, which can make some queries
2151** slower. But the QPSG has the advantage of more predictable behavior. With
2152** the QPSG active, SQLite will always use the same query plan in the field as
2153** was used during testing in the lab.
2154** The first argument to this setting is an integer which is 0 to disable
2155** the QPSG, positive to enable QPSG, or negative to leave the setting
2156** unchanged. The second parameter is a pointer to an integer into which
2157** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
2158** following this call.
2159** </dd>
2162** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
2163** include output for any operations performed by trigger programs. This
2164** option is used to set or clear (the default) a flag that governs this
2165** behavior. The first parameter passed to this operation is an integer -
2166** positive to enable output for trigger programs, or zero to disable it,
2167** or negative to leave the setting unchanged.
2168** The second parameter is a pointer to an integer into which is written
2169** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
2170** it is not disabled, 1 if it is.
2171** </dd>
2174** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
2175** [VACUUM] in order to reset a database back to an empty database
2176** with no schema and no content. The following process works even for
2177** a badly corrupted database file:
2178** <ol>
2179** <li> If the database connection is newly opened, make sure it has read the
2180** database schema by preparing then discarding some query against the
2181** database, or calling sqlite3_table_column_metadata(), ignoring any
2182** errors. This step is only necessary if the application desires to keep
2183** the database in WAL mode after the reset if it was in WAL mode before
2184** the reset.
2185** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
2186** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
2187** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
2188** </ol>
2189** Because resetting a database is destructive and irreversible, the
2190** process requires the use of this obscure API and multiple steps to help
2191** ensure that it does not happen by accident.
2194** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
2195** "defensive" flag for a database connection. When the defensive
2196** flag is enabled, language features that allow ordinary SQL to
2197** deliberately corrupt the database file are disabled. The disabled
2198** features include but are not limited to the following:
2199** <ul>
2200** <li> The [PRAGMA writable_schema=ON] statement.
2201** <li> Writes to the [sqlite_dbpage] virtual table.
2202** <li> Direct writes to [shadow tables].
2203** </ul>
2204** </dd>
2207** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
2208** "writable_schema" flag. This has the same effect and is logically equivalent
2209** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF].
2210** The first argument to this setting is an integer which is 0 to disable
2211** the writable_schema, positive to enable writable_schema, or negative to
2212** leave the setting unchanged. The second parameter is a pointer to an
2213** integer into which is written 0 or 1 to indicate whether the writable_schema
2214** is enabled or disabled following this call.
2215** </dd>
2216** </dl>
2218#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */
2219#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
2220#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
2221#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
2222#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
2223#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
2224#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */
2225#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */
2226#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */
2227#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */
2228#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */
2229#define SQLITE_DBCONFIG_WRITABLE_SCHEMA 1011 /* int int* */
2230#define SQLITE_DBCONFIG_MAX 1011 /* Largest DBCONFIG */
2233** CAPI3REF: Enable Or Disable Extended Result Codes
2234** METHOD: sqlite3
2236** ^The sqlite3_extended_result_codes() routine enables or disables the
2237** [extended result codes] feature of SQLite. ^The extended result
2238** codes are disabled by default for historical compatibility.
2240SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
2243** CAPI3REF: Last Insert Rowid
2244** METHOD: sqlite3
2246** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
2247** has a unique 64-bit signed
2248** integer key called the [ROWID | "rowid"]. ^The rowid is always available
2249** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
2250** names are not also used by explicitly declared columns. ^If
2251** the table has a column of type [INTEGER PRIMARY KEY] then that column
2252** is another alias for the rowid.
2254** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
2255** the most recent successful [INSERT] into a rowid table or [virtual table]
2256** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
2257** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
2258** on the database connection D, then sqlite3_last_insert_rowid(D) returns
2259** zero.
2261** As well as being set automatically as rows are inserted into database
2262** tables, the value returned by this function may be set explicitly by
2263** [sqlite3_set_last_insert_rowid()]
2265** Some virtual table implementations may INSERT rows into rowid tables as
2266** part of committing a transaction (e.g. to flush data accumulated in memory
2267** to disk). In this case subsequent calls to this function return the rowid
2268** associated with these internal INSERT operations, which leads to
2269** unintuitive results. Virtual table implementations that do write to rowid
2270** tables in this way can avoid this problem by restoring the original
2271** rowid value using [sqlite3_set_last_insert_rowid()] before returning
2272** control to the user.
2274** ^(If an [INSERT] occurs within a trigger then this routine will
2275** return the [rowid] of the inserted row as long as the trigger is
2276** running. Once the trigger program ends, the value returned
2277** by this routine reverts to what it was before the trigger was fired.)^
2279** ^An [INSERT] that fails due to a constraint violation is not a
2280** successful [INSERT] and does not change the value returned by this
2282** and INSERT OR ABORT make no changes to the return value of this
2283** routine when their insertion fails. ^(When INSERT OR REPLACE
2284** encounters a constraint violation, it does not fail. The
2285** INSERT continues to completion after deleting rows that caused
2286** the constraint problem so INSERT OR REPLACE will always change
2287** the return value of this interface.)^
2289** ^For the purposes of this routine, an [INSERT] is considered to
2290** be successful even if it is subsequently rolled back.
2292** This function is accessible to SQL statements via the
2293** [last_insert_rowid() SQL function].
2295** If a separate thread performs a new [INSERT] on the same
2296** database connection while the [sqlite3_last_insert_rowid()]
2297** function is running and thus changes the last insert [rowid],
2298** then the value returned by [sqlite3_last_insert_rowid()] is
2299** unpredictable and might not equal either the old or the new
2300** last insert [rowid].
2302SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
2305** CAPI3REF: Set the Last Insert Rowid value.
2306** METHOD: sqlite3
2308** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
2309** set the value returned by calling sqlite3_last_insert_rowid(D) to R
2310** without inserting a row into the database.
2312SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
2315** CAPI3REF: Count The Number Of Rows Modified
2316** METHOD: sqlite3
2318** ^This function returns the number of rows modified, inserted or
2319** deleted by the most recently completed INSERT, UPDATE or DELETE
2320** statement on the database connection specified by the only parameter.
2321** ^Executing any other type of SQL statement does not modify the value
2322** returned by this function.
2324** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
2325** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
2326** [foreign key actions] or [REPLACE] constraint resolution are not counted.
2328** Changes to a view that are intercepted by
2329** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
2330** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
2331** DELETE statement run on a view is always zero. Only changes made to real
2332** tables are counted.
2334** Things are more complicated if the sqlite3_changes() function is
2335** executed while a trigger program is running. This may happen if the
2336** program uses the [changes() SQL function], or if some other callback
2337** function invokes sqlite3_changes() directly. Essentially:
2339** <ul>
2340** <li> ^(Before entering a trigger program the value returned by
2341** sqlite3_changes() function is saved. After the trigger program
2342** has finished, the original value is restored.)^
2344** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
2345** statement sets the value returned by sqlite3_changes()
2346** upon completion as normal. Of course, this value will not include
2347** any changes performed by sub-triggers, as the sqlite3_changes()
2348** value will be saved and restored after each sub-trigger has run.)^
2349** </ul>
2351** ^This means that if the changes() SQL function (or similar) is used
2352** by the first INSERT, UPDATE or DELETE statement within a trigger, it
2353** returns the value as set when the calling statement began executing.
2354** ^If it is used by the second or subsequent such statement within a trigger
2355** program, the value returned reflects the number of rows modified by the
2356** previous INSERT, UPDATE or DELETE statement within the same trigger.
2358** If a separate thread makes changes on the same database connection
2359** while [sqlite3_changes()] is running then the value returned
2360** is unpredictable and not meaningful.
2362** See also:
2363** <ul>
2364** <li> the [sqlite3_total_changes()] interface
2365** <li> the [count_changes pragma]
2366** <li> the [changes() SQL function]
2367** <li> the [data_version pragma]
2368** </ul>
2370SQLITE_API int sqlite3_changes(sqlite3*);
2373** CAPI3REF: Total Number Of Rows Modified
2374** METHOD: sqlite3
2376** ^This function returns the total number of rows inserted, modified or
2377** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2378** since the database connection was opened, including those executed as
2379** part of trigger programs. ^Executing any other type of SQL statement
2380** does not affect the value returned by sqlite3_total_changes().
2382** ^Changes made as part of [foreign key actions] are included in the
2383** count, but those made as part of REPLACE constraint resolution are
2384** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2385** are not counted.
2387** The [sqlite3_total_changes(D)] interface only reports the number
2388** of rows that changed due to SQL statement run against database
2389** connection D. Any changes by other database connections are ignored.
2390** To detect changes against a database file from other database
2391** connections use the [PRAGMA data_version] command or the
2392** [SQLITE_FCNTL_DATA_VERSION] [file control].
2394** If a separate thread makes changes on the same database connection
2395** while [sqlite3_total_changes()] is running then the value
2396** returned is unpredictable and not meaningful.
2398** See also:
2399** <ul>
2400** <li> the [sqlite3_changes()] interface
2401** <li> the [count_changes pragma]
2402** <li> the [changes() SQL function]
2403** <li> the [data_version pragma]
2404** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control]
2405** </ul>
2407SQLITE_API int sqlite3_total_changes(sqlite3*);
2410** CAPI3REF: Interrupt A Long-Running Query
2411** METHOD: sqlite3
2413** ^This function causes any pending database operation to abort and
2414** return at its earliest opportunity. This routine is typically
2415** called in response to a user action such as pressing "Cancel"
2416** or Ctrl-C where the user wants a long query operation to halt
2417** immediately.
2419** ^It is safe to call this routine from a thread different from the
2420** thread that is currently running the database operation. But it
2421** is not safe to call this routine with a [database connection] that
2422** is closed or might close before sqlite3_interrupt() returns.
2424** ^If an SQL operation is very nearly finished at the time when
2425** sqlite3_interrupt() is called, then it might not have an opportunity
2426** to be interrupted and might continue to completion.
2428** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2429** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2430** that is inside an explicit transaction, then the entire transaction
2431** will be rolled back automatically.
2433** ^The sqlite3_interrupt(D) call is in effect until all currently running
2434** SQL statements on [database connection] D complete. ^Any new SQL statements
2435** that are started after the sqlite3_interrupt() call and before the
2436** running statements reaches zero are interrupted as if they had been
2437** running prior to the sqlite3_interrupt() call. ^New SQL statements
2438** that are started after the running statement count reaches zero are
2439** not effected by the sqlite3_interrupt().
2440** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2441** SQL statements is a no-op and has no effect on SQL statements
2442** that are started after the sqlite3_interrupt() call returns.
2444SQLITE_API void sqlite3_interrupt(sqlite3*);
2447** CAPI3REF: Determine If An SQL Statement Is Complete
2449** These routines are useful during command-line input to determine if the
2450** currently entered text seems to form a complete SQL statement or
2451** if additional input is needed before sending the text into
2452** SQLite for parsing. ^These routines return 1 if the input string
2453** appears to be a complete SQL statement. ^A statement is judged to be
2454** complete if it ends with a semicolon token and is not a prefix of a
2455** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
2456** string literals or quoted identifier names or comments are not
2457** independent tokens (they are part of the token in which they are
2458** embedded) and thus do not count as a statement terminator. ^Whitespace
2459** and comments that follow the final semicolon are ignored.
2461** ^These routines return 0 if the statement is incomplete. ^If a
2462** memory allocation fails, then SQLITE_NOMEM is returned.
2464** ^These routines do not parse the SQL statements thus
2465** will not detect syntactically incorrect SQL.
2467** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2468** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2469** automatically by sqlite3_complete16(). If that initialization fails,
2470** then the return value from sqlite3_complete16() will be non-zero
2471** regardless of whether or not the input SQL is complete.)^
2473** The input to [sqlite3_complete()] must be a zero-terminated
2474** UTF-8 string.
2476** The input to [sqlite3_complete16()] must be a zero-terminated
2477** UTF-16 string in native byte order.
2479SQLITE_API int sqlite3_complete(const char *sql);
2480SQLITE_API int sqlite3_complete16(const void *sql);
2483** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2484** KEYWORDS: {busy-handler callback} {busy handler}
2485** METHOD: sqlite3
2487** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2488** that might be invoked with argument P whenever
2489** an attempt is made to access a database table associated with
2490** [database connection] D when another thread
2491** or process has the table locked.
2492** The sqlite3_busy_handler() interface is used to implement
2493** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2495** ^If the busy callback is NULL, then [SQLITE_BUSY]
2496** is returned immediately upon encountering the lock. ^If the busy callback
2497** is not NULL, then the callback might be invoked with two arguments.
2499** ^The first argument to the busy handler is a copy of the void* pointer which
2500** is the third argument to sqlite3_busy_handler(). ^The second argument to
2501** the busy handler callback is the number of times that the busy handler has
2502** been invoked previously for the same locking event. ^If the
2503** busy callback returns 0, then no additional attempts are made to
2504** access the database and [SQLITE_BUSY] is returned
2505** to the application.
2506** ^If the callback returns non-zero, then another attempt
2507** is made to access the database and the cycle repeats.
2509** The presence of a busy handler does not guarantee that it will be invoked
2510** when there is lock contention. ^If SQLite determines that invoking the busy
2511** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2512** to the application instead of invoking the
2513** busy handler.
2514** Consider a scenario where one process is holding a read lock that
2515** it is trying to promote to a reserved lock and
2516** a second process is holding a reserved lock that it is trying
2517** to promote to an exclusive lock. The first process cannot proceed
2518** because it is blocked by the second and the second process cannot
2519** proceed because it is blocked by the first. If both processes
2520** invoke the busy handlers, neither will make any progress. Therefore,
2521** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2522** will induce the first process to release its read lock and allow
2523** the second process to proceed.
2525** ^The default busy callback is NULL.
2527** ^(There can only be a single busy handler defined for each
2528** [database connection]. Setting a new busy handler clears any
2529** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
2530** or evaluating [PRAGMA busy_timeout=N] will change the
2531** busy handler and thus clear any previously set busy handler.
2533** The busy callback should not take any actions which modify the
2534** database connection that invoked the busy handler. In other words,
2535** the busy handler is not reentrant. Any such actions
2536** result in undefined behavior.
2538** A busy handler must not close the database connection
2539** or [prepared statement] that invoked the busy handler.
2541SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
2544** CAPI3REF: Set A Busy Timeout
2545** METHOD: sqlite3
2547** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2548** for a specified amount of time when a table is locked. ^The handler
2549** will sleep multiple times until at least "ms" milliseconds of sleeping
2550** have accumulated. ^After at least "ms" milliseconds of sleeping,
2551** the handler returns 0 which causes [sqlite3_step()] to return
2552** [SQLITE_BUSY].
2554** ^Calling this routine with an argument less than or equal to zero
2555** turns off all busy handlers.
2557** ^(There can only be a single busy handler for a particular
2558** [database connection] at any given moment. If another busy handler
2559** was defined (using [sqlite3_busy_handler()]) prior to calling
2560** this routine, that other busy handler is cleared.)^
2562** See also: [PRAGMA busy_timeout]
2564SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2567** CAPI3REF: Convenience Routines For Running Queries
2568** METHOD: sqlite3
2570** This is a legacy interface that is preserved for backwards compatibility.
2571** Use of this interface is not recommended.
2573** Definition: A <b>result table</b> is memory data structure created by the
2574** [sqlite3_get_table()] interface. A result table records the
2575** complete query results from one or more queries.
2577** The table conceptually has a number of rows and columns. But
2578** these numbers are not part of the result table itself. These
2579** numbers are obtained separately. Let N be the number of rows
2580** and M be the number of columns.
2582** A result table is an array of pointers to zero-terminated UTF-8 strings.
2583** There are (N+1)*M elements in the array. The first M pointers point
2584** to zero-terminated strings that contain the names of the columns.
2585** The remaining entries all point to query results. NULL values result
2586** in NULL pointers. All other values are in their UTF-8 zero-terminated
2587** string representation as returned by [sqlite3_column_text()].
2589** A result table might consist of one or more memory allocations.
2590** It is not safe to pass a result table directly to [sqlite3_free()].
2591** A result table should be deallocated using [sqlite3_free_table()].
2593** ^(As an example of the result table format, suppose a query result
2594** is as follows:
2596** <blockquote><pre>
2597** Name | Age
2598** -----------------------
2599** Alice | 43
2600** Bob | 28
2601** Cindy | 21
2602** </pre></blockquote>
2604** There are two column (M==2) and three rows (N==3). Thus the
2605** result table has 8 entries. Suppose the result table is stored
2606** in an array names azResult. Then azResult holds this content:
2608** <blockquote><pre>
2609** azResult&#91;0] = "Name";
2610** azResult&#91;1] = "Age";
2611** azResult&#91;2] = "Alice";
2612** azResult&#91;3] = "43";
2613** azResult&#91;4] = "Bob";
2614** azResult&#91;5] = "28";
2615** azResult&#91;6] = "Cindy";
2616** azResult&#91;7] = "21";
2617** </pre></blockquote>)^
2619** ^The sqlite3_get_table() function evaluates one or more
2620** semicolon-separated SQL statements in the zero-terminated UTF-8
2621** string of its 2nd parameter and returns a result table to the
2622** pointer given in its 3rd parameter.
2624** After the application has finished with the result from sqlite3_get_table(),
2625** it must pass the result table pointer to sqlite3_free_table() in order to
2626** release the memory that was malloced. Because of the way the
2627** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2628** function must not try to call [sqlite3_free()] directly. Only
2629** [sqlite3_free_table()] is able to release the memory properly and safely.
2631** The sqlite3_get_table() interface is implemented as a wrapper around
2632** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
2633** to any internal data structures of SQLite. It uses only the public
2634** interface defined here. As a consequence, errors that occur in the
2635** wrapper layer outside of the internal [sqlite3_exec()] call are not
2636** reflected in subsequent calls to [sqlite3_errcode()] or
2637** [sqlite3_errmsg()].
2639SQLITE_API int sqlite3_get_table(
2640 sqlite3 *db, /* An open database */
2641 const char *zSql, /* SQL to be evaluated */
2642 char ***pazResult, /* Results of the query */
2643 int *pnRow, /* Number of result rows written here */
2644 int *pnColumn, /* Number of result columns written here */
2645 char **pzErrmsg /* Error msg written here */
2647SQLITE_API void sqlite3_free_table(char **result);
2650** CAPI3REF: Formatted String Printing Functions
2652** These routines are work-alikes of the "printf()" family of functions
2653** from the standard C library.
2654** These routines understand most of the common formatting options from
2655** the standard library printf()
2656** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
2657** See the [built-in printf()] documentation for details.
2659** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2660** results into memory obtained from [sqlite3_malloc64()].
2661** The strings returned by these two routines should be
2662** released by [sqlite3_free()]. ^Both routines return a
2663** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
2664** memory to hold the resulting string.
2666** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2667** the standard C library. The result is written into the
2668** buffer supplied as the second parameter whose size is given by
2669** the first parameter. Note that the order of the
2670** first two parameters is reversed from snprintf().)^ This is an
2671** historical accident that cannot be fixed without breaking
2672** backwards compatibility. ^(Note also that sqlite3_snprintf()
2673** returns a pointer to its buffer instead of the number of
2674** characters actually written into the buffer.)^ We admit that
2675** the number of characters written would be a more useful return
2676** value but we cannot change the implementation of sqlite3_snprintf()
2677** now without breaking compatibility.
2679** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2680** guarantees that the buffer is always zero-terminated. ^The first
2681** parameter "n" is the total size of the buffer, including space for
2682** the zero terminator. So the longest string that can be completely
2683** written will be n-1 characters.
2685** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2687** See also: [built-in printf()], [printf() SQL function]
2689SQLITE_API char *sqlite3_mprintf(const char*,...);
2690SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2691SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2692SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2695** CAPI3REF: Memory Allocation Subsystem
2697** The SQLite core uses these three routines for all of its own
2698** internal memory allocation needs. "Core" in the previous sentence
2699** does not include operating-system specific VFS implementation. The
2700** Windows VFS uses native malloc() and free() for some operations.
2702** ^The sqlite3_malloc() routine returns a pointer to a block
2703** of memory at least N bytes in length, where N is the parameter.
2704** ^If sqlite3_malloc() is unable to obtain sufficient free
2705** memory, it returns a NULL pointer. ^If the parameter N to
2706** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2707** a NULL pointer.
2709** ^The sqlite3_malloc64(N) routine works just like
2710** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2711** of a signed 32-bit integer.
2713** ^Calling sqlite3_free() with a pointer previously returned
2714** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2715** that it might be reused. ^The sqlite3_free() routine is
2716** a no-op if is called with a NULL pointer. Passing a NULL pointer
2717** to sqlite3_free() is harmless. After being freed, memory
2718** should neither be read nor written. Even reading previously freed
2719** memory might result in a segmentation fault or other severe error.
2720** Memory corruption, a segmentation fault, or other severe error
2721** might result if sqlite3_free() is called with a non-NULL pointer that
2722** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2724** ^The sqlite3_realloc(X,N) interface attempts to resize a
2725** prior memory allocation X to be at least N bytes.
2726** ^If the X parameter to sqlite3_realloc(X,N)
2727** is a NULL pointer then its behavior is identical to calling
2728** sqlite3_malloc(N).
2729** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2730** negative then the behavior is exactly the same as calling
2731** sqlite3_free(X).
2732** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2733** of at least N bytes in size or NULL if insufficient memory is available.
2734** ^If M is the size of the prior allocation, then min(N,M) bytes
2735** of the prior allocation are copied into the beginning of buffer returned
2736** by sqlite3_realloc(X,N) and the prior allocation is freed.
2737** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2738** prior allocation is not freed.
2740** ^The sqlite3_realloc64(X,N) interfaces works the same as
2741** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2742** of a 32-bit signed integer.
2744** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2745** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2746** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2747** ^The value returned by sqlite3_msize(X) might be larger than the number
2748** of bytes requested when X was allocated. ^If X is a NULL pointer then
2749** sqlite3_msize(X) returns zero. If X points to something that is not
2750** the beginning of memory allocation, or if it points to a formerly
2751** valid memory allocation that has now been freed, then the behavior
2752** of sqlite3_msize(X) is undefined and possibly harmful.
2754** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2755** sqlite3_malloc64(), and sqlite3_realloc64()
2756** is always aligned to at least an 8 byte boundary, or to a
2757** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2758** option is used.
2760** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2761** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2762** implementation of these routines to be omitted. That capability
2763** is no longer provided. Only built-in memory allocators can be used.
2765** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2766** the system malloc() and free() directly when converting
2767** filenames between the UTF-8 encoding used by SQLite
2768** and whatever filename encoding is used by the particular Windows
2769** installation. Memory allocation errors were detected, but
2770** they were reported back as [SQLITE_CANTOPEN] or
2771** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2773** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2774** must be either NULL or else pointers obtained from a prior
2775** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2776** not yet been released.
2778** The application must not read or write any part of
2779** a block of memory after it has been released using
2780** [sqlite3_free()] or [sqlite3_realloc()].
2782SQLITE_API void *sqlite3_malloc(int);
2783SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
2784SQLITE_API void *sqlite3_realloc(void*, int);
2785SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
2786SQLITE_API void sqlite3_free(void*);
2787SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
2790** CAPI3REF: Memory Allocator Statistics
2792** SQLite provides these two interfaces for reporting on the status
2793** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2794** routines, which form the built-in memory allocation subsystem.
2796** ^The [sqlite3_memory_used()] routine returns the number of bytes
2797** of memory currently outstanding (malloced but not freed).
2798** ^The [sqlite3_memory_highwater()] routine returns the maximum
2799** value of [sqlite3_memory_used()] since the high-water mark
2800** was last reset. ^The values returned by [sqlite3_memory_used()] and
2801** [sqlite3_memory_highwater()] include any overhead
2802** added by SQLite in its implementation of [sqlite3_malloc()],
2803** but not overhead added by the any underlying system library
2804** routines that [sqlite3_malloc()] may call.
2806** ^The memory high-water mark is reset to the current value of
2807** [sqlite3_memory_used()] if and only if the parameter to
2808** [sqlite3_memory_highwater()] is true. ^The value returned
2809** by [sqlite3_memory_highwater(1)] is the high-water mark
2810** prior to the reset.
2812SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2813SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2816** CAPI3REF: Pseudo-Random Number Generator
2818** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2819** select random [ROWID | ROWIDs] when inserting new records into a table that
2820** already uses the largest possible [ROWID]. The PRNG is also used for
2821** the build-in random() and randomblob() SQL functions. This interface allows
2822** applications to access the same PRNG for other purposes.
2824** ^A call to this routine stores N bytes of randomness into buffer P.
2825** ^The P parameter can be a NULL pointer.
2827** ^If this routine has not been previously called or if the previous
2828** call had N less than one or a NULL pointer for P, then the PRNG is
2829** seeded using randomness obtained from the xRandomness method of
2830** the default [sqlite3_vfs] object.
2831** ^If the previous call to this routine had an N of 1 or more and a
2832** non-NULL P then the pseudo-randomness is generated
2833** internally and without recourse to the [sqlite3_vfs] xRandomness
2834** method.
2836SQLITE_API void sqlite3_randomness(int N, void *P);
2839** CAPI3REF: Compile-Time Authorization Callbacks
2840** METHOD: sqlite3
2841** KEYWORDS: {authorizer callback}
2843** ^This routine registers an authorizer callback with a particular
2844** [database connection], supplied in the first argument.
2845** ^The authorizer callback is invoked as SQL statements are being compiled
2846** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2847** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
2848** and [sqlite3_prepare16_v3()]. ^At various
2849** points during the compilation process, as logic is being created
2850** to perform various actions, the authorizer callback is invoked to
2851** see if those actions are allowed. ^The authorizer callback should
2852** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2853** specific action but allow the SQL statement to continue to be
2854** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2855** rejected with an error. ^If the authorizer callback returns
2856** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2857** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2858** the authorizer will fail with an error message.
2860** When the callback returns [SQLITE_OK], that means the operation
2861** requested is ok. ^When the callback returns [SQLITE_DENY], the
2862** [sqlite3_prepare_v2()] or equivalent call that triggered the
2863** authorizer will fail with an error message explaining that
2864** access is denied.
2866** ^The first parameter to the authorizer callback is a copy of the third
2867** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2868** to the callback is an integer [SQLITE_COPY | action code] that specifies
2869** the particular action to be authorized. ^The third through sixth parameters
2870** to the callback are either NULL pointers or zero-terminated strings
2871** that contain additional details about the action to be authorized.
2872** Applications must always be prepared to encounter a NULL pointer in any
2873** of the third through the sixth parameters of the authorization callback.
2875** ^If the action code is [SQLITE_READ]
2876** and the callback returns [SQLITE_IGNORE] then the
2877** [prepared statement] statement is constructed to substitute
2878** a NULL value in place of the table column that would have
2879** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2880** return can be used to deny an untrusted user access to individual
2881** columns of a table.
2882** ^When a table is referenced by a [SELECT] but no column values are
2883** extracted from that table (for example in a query like
2884** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
2885** is invoked once for that table with a column name that is an empty string.
2886** ^If the action code is [SQLITE_DELETE] and the callback returns
2887** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2888** [truncate optimization] is disabled and all rows are deleted individually.
2890** An authorizer is used when [sqlite3_prepare | preparing]
2891** SQL statements from an untrusted source, to ensure that the SQL statements
2892** do not try to access data they are not allowed to see, or that they do not
2893** try to execute malicious statements that damage the database. For
2894** example, an application may allow a user to enter arbitrary
2895** SQL queries for evaluation by a database. But the application does
2896** not want the user to be able to make arbitrary changes to the
2897** database. An authorizer could then be put in place while the
2898** user-entered SQL is being [sqlite3_prepare | prepared] that
2899** disallows everything except [SELECT] statements.
2901** Applications that need to process SQL from untrusted sources
2902** might also consider lowering resource limits using [sqlite3_limit()]
2903** and limiting database size using the [max_page_count] [PRAGMA]
2904** in addition to using an authorizer.
2906** ^(Only a single authorizer can be in place on a database connection
2907** at a time. Each call to sqlite3_set_authorizer overrides the
2908** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2909** The authorizer is disabled by default.
2911** The authorizer callback must not do anything that will modify
2912** the database connection that invoked the authorizer callback.
2913** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2914** database connections for the meaning of "modify" in this paragraph.
2916** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2917** statement might be re-prepared during [sqlite3_step()] due to a
2918** schema change. Hence, the application should ensure that the
2919** correct authorizer callback remains in place during the [sqlite3_step()].
2921** ^Note that the authorizer callback is invoked only during
2922** [sqlite3_prepare()] or its variants. Authorization is not
2923** performed during statement evaluation in [sqlite3_step()], unless
2924** as stated in the previous paragraph, sqlite3_step() invokes
2925** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2927SQLITE_API int sqlite3_set_authorizer(
2928 sqlite3*,
2929 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2930 void *pUserData
2934** CAPI3REF: Authorizer Return Codes
2936** The [sqlite3_set_authorizer | authorizer callback function] must
2937** return either [SQLITE_OK] or one of these two constants in order
2938** to signal SQLite whether or not the action is permitted. See the
2939** [sqlite3_set_authorizer | authorizer documentation] for additional
2940** information.
2942** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2943** returned from the [sqlite3_vtab_on_conflict()] interface.
2945#define SQLITE_DENY 1 /* Abort the SQL statement with an error */
2946#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
2949** CAPI3REF: Authorizer Action Codes
2951** The [sqlite3_set_authorizer()] interface registers a callback function
2952** that is invoked to authorize certain SQL statement actions. The
2953** second parameter to the callback is an integer code that specifies
2954** what action is being authorized. These are the integer action codes that
2955** the authorizer callback may be passed.
2957** These action code values signify what kind of operation is to be
2958** authorized. The 3rd and 4th parameters to the authorization
2959** callback function will be parameters or NULL depending on which of these
2960** codes is used as the second parameter. ^(The 5th parameter to the
2961** authorizer callback is the name of the database ("main", "temp",
2962** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2963** is the name of the inner-most trigger or view that is responsible for
2964** the access attempt or NULL if this access attempt is directly from
2965** top-level SQL code.
2967/******************************************* 3rd ************ 4th ***********/
2968#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
2969#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
2970#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
2971#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
2972#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
2973#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
2974#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2975#define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2976#define SQLITE_DELETE 9 /* Table Name NULL */
2977#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2978#define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2979#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2980#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2981#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2982#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2983#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2984#define SQLITE_DROP_VIEW 17 /* View Name NULL */
2985#define SQLITE_INSERT 18 /* Table Name NULL */
2986#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2987#define SQLITE_READ 20 /* Table Name Column Name */
2988#define SQLITE_SELECT 21 /* NULL NULL */
2989#define SQLITE_TRANSACTION 22 /* Operation NULL */
2990#define SQLITE_UPDATE 23 /* Table Name Column Name */
2991#define SQLITE_ATTACH 24 /* Filename NULL */
2992#define SQLITE_DETACH 25 /* Database Name NULL */
2993#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2994#define SQLITE_REINDEX 27 /* Index Name NULL */
2995#define SQLITE_ANALYZE 28 /* Table Name NULL */
2996#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2997#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2998#define SQLITE_FUNCTION 31 /* NULL Function Name */
2999#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
3000#define SQLITE_COPY 0 /* No longer used */
3001#define SQLITE_RECURSIVE 33 /* NULL NULL */
3004** CAPI3REF: Tracing And Profiling Functions
3005** METHOD: sqlite3
3007** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
3008** instead of the routines described here.
3010** These routines register callback functions that can be used for
3011** tracing and profiling the execution of SQL statements.
3013** ^The callback function registered by sqlite3_trace() is invoked at
3014** various times when an SQL statement is being run by [sqlite3_step()].
3015** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
3016** SQL statement text as the statement first begins executing.
3017** ^(Additional sqlite3_trace() callbacks might occur
3018** as each triggered subprogram is entered. The callbacks for triggers
3019** contain a UTF-8 SQL comment that identifies the trigger.)^
3021** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
3022** the length of [bound parameter] expansion in the output of sqlite3_trace().
3024** ^The callback function registered by sqlite3_profile() is invoked
3025** as each SQL statement finishes. ^The profile callback contains
3026** the original statement text and an estimate of wall-clock time
3027** of how long that statement took to run. ^The profile callback
3028** time is in units of nanoseconds, however the current implementation
3029** is only capable of millisecond resolution so the six least significant
3030** digits in the time are meaningless. Future versions of SQLite
3031** might provide greater resolution on the profiler callback. Invoking
3032** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the
3033** profile callback.
3035SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
3036 void(*xTrace)(void*,const char*), void*);
3037SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
3038 void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
3041** CAPI3REF: SQL Trace Event Codes
3044** These constants identify classes of events that can be monitored
3045** using the [sqlite3_trace_v2()] tracing logic. The M argument
3046** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
3047** the following constants. ^The first argument to the trace callback
3048** is one of the following constants.
3050** New tracing constants may be added in future releases.
3052** ^A trace callback has four arguments: xCallback(T,C,P,X).
3053** ^The T argument is one of the integer type codes above.
3054** ^The C argument is a copy of the context pointer passed in as the
3055** fourth argument to [sqlite3_trace_v2()].
3056** The P and X arguments are pointers whose meanings depend on T.
3058** <dl>
3060** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
3061** first begins running and possibly at other times during the
3062** execution of the prepared statement, such as at the start of each
3063** trigger subprogram. ^The P argument is a pointer to the
3064** [prepared statement]. ^The X argument is a pointer to a string which
3065** is the unexpanded SQL text of the prepared statement or an SQL comment
3066** that indicates the invocation of a trigger. ^The callback can compute
3067** the same text that would have been returned by the legacy [sqlite3_trace()]
3068** interface by using the X argument when X begins with "--" and invoking
3069** [sqlite3_expanded_sql(P)] otherwise.
3072** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
3073** information as is provided by the [sqlite3_profile()] callback.
3074** ^The P argument is a pointer to the [prepared statement] and the
3075** X argument points to a 64-bit integer which is the estimated of
3076** the number of nanosecond that the prepared statement took to run.
3077** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
3080** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
3081** statement generates a single row of result.
3082** ^The P argument is a pointer to the [prepared statement] and the
3083** X argument is unused.
3086** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
3087** connection closes.
3088** ^The P argument is a pointer to the [database connection] object
3089** and the X argument is unused.
3090** </dl>
3092#define SQLITE_TRACE_STMT 0x01
3093#define SQLITE_TRACE_PROFILE 0x02
3094#define SQLITE_TRACE_ROW 0x04
3095#define SQLITE_TRACE_CLOSE 0x08
3098** CAPI3REF: SQL Trace Hook
3099** METHOD: sqlite3
3101** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
3102** function X against [database connection] D, using property mask M
3103** and context pointer P. ^If the X callback is
3104** NULL or if the M mask is zero, then tracing is disabled. The
3105** M argument should be the bitwise OR-ed combination of
3106** zero or more [SQLITE_TRACE] constants.
3108** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides
3109** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2().
3111** ^The X callback is invoked whenever any of the events identified by
3112** mask M occur. ^The integer return value from the callback is currently
3113** ignored, though this may change in future releases. Callback
3114** implementations should return zero to ensure future compatibility.
3116** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
3117** ^The T argument is one of the [SQLITE_TRACE]
3118** constants to indicate why the callback was invoked.
3119** ^The C argument is a copy of the context pointer.
3120** The P and X arguments are pointers whose meanings depend on T.
3122** The sqlite3_trace_v2() interface is intended to replace the legacy
3123** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
3124** are deprecated.
3126SQLITE_API int sqlite3_trace_v2(
3127 sqlite3*,
3128 unsigned uMask,
3129 int(*xCallback)(unsigned,void*,void*,void*),
3130 void *pCtx
3134** CAPI3REF: Query Progress Callbacks
3135** METHOD: sqlite3
3137** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
3138** function X to be invoked periodically during long running calls to
3139** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
3140** database connection D. An example use for this
3141** interface is to keep a GUI updated during a large query.
3143** ^The parameter P is passed through as the only parameter to the
3144** callback function X. ^The parameter N is the approximate number of
3145** [virtual machine instructions] that are evaluated between successive
3146** invocations of the callback X. ^If N is less than one then the progress
3147** handler is disabled.
3149** ^Only a single progress handler may be defined at one time per
3150** [database connection]; setting a new progress handler cancels the
3151** old one. ^Setting parameter X to NULL disables the progress handler.
3152** ^The progress handler is also disabled by setting N to a value less
3153** than 1.
3155** ^If the progress callback returns non-zero, the operation is
3156** interrupted. This feature can be used to implement a
3157** "Cancel" button on a GUI progress dialog box.
3159** The progress handler callback must not do anything that will modify
3160** the database connection that invoked the progress handler.
3161** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3162** database connections for the meaning of "modify" in this paragraph.
3165SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
3168** CAPI3REF: Opening A New Database Connection
3169** CONSTRUCTOR: sqlite3
3171** ^These routines open an SQLite database file as specified by the
3172** filename argument. ^The filename argument is interpreted as UTF-8 for
3173** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
3174** order for sqlite3_open16(). ^(A [database connection] handle is usually
3175** returned in *ppDb, even if an error occurs. The only exception is that
3176** if SQLite is unable to allocate memory to hold the [sqlite3] object,
3177** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
3178** object.)^ ^(If the database is opened (and/or created) successfully, then
3179** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
3180** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
3181** an English language description of the error following a failure of any
3182** of the sqlite3_open() routines.
3184** ^The default encoding will be UTF-8 for databases created using
3185** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases
3186** created using sqlite3_open16() will be UTF-16 in the native byte order.
3188** Whether or not an error occurs when it is opened, resources
3189** associated with the [database connection] handle should be released by
3190** passing it to [sqlite3_close()] when it is no longer required.
3192** The sqlite3_open_v2() interface works like sqlite3_open()
3193** except that it accepts two additional parameters for additional control
3194** over the new database connection. ^(The flags parameter to
3195** sqlite3_open_v2() can take one of
3196** the following three values, optionally combined with the
3200** <dl>
3201** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
3202** <dd>The database is opened in read-only mode. If the database does not
3203** already exist, an error is returned.</dd>)^
3205** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
3206** <dd>The database is opened for reading and writing if possible, or reading
3207** only if the file is write protected by the operating system. In either
3208** case the database must already exist, otherwise an error is returned.</dd>)^
3211** <dd>The database is opened for reading and writing, and is created if
3212** it does not already exist. This is the behavior that is always used for
3213** sqlite3_open() and sqlite3_open16().</dd>)^
3214** </dl>
3216** If the 3rd parameter to sqlite3_open_v2() is not one of the
3217** combinations shown above optionally combined with other
3219** then the behavior is undefined.
3221** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
3222** opens in the multi-thread [threading mode] as long as the single-thread
3223** mode has not been set at compile-time or start-time. ^If the
3224** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
3225** in the serialized [threading mode] unless single-thread was
3226** previously selected at compile-time or start-time.
3227** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
3228** eligible to use [shared cache mode], regardless of whether or not shared
3229** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
3230** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
3231** participate in [shared cache mode] even if it is enabled.
3233** ^The fourth parameter to sqlite3_open_v2() is the name of the
3234** [sqlite3_vfs] object that defines the operating system interface that
3235** the new database connection should use. ^If the fourth parameter is
3236** a NULL pointer then the default [sqlite3_vfs] object is used.
3238** ^If the filename is ":memory:", then a private, temporary in-memory database
3239** is created for the connection. ^This in-memory database will vanish when
3240** the database connection is closed. Future versions of SQLite might
3241** make use of additional special filenames that begin with the ":" character.
3242** It is recommended that when a database filename actually does begin with
3243** a ":" character you should prefix the filename with a pathname such as
3244** "./" to avoid ambiguity.
3246** ^If the filename is an empty string, then a private, temporary
3247** on-disk database will be created. ^This private database will be
3248** automatically deleted as soon as the database connection is closed.
3250** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
3252** ^If [URI filename] interpretation is enabled, and the filename argument
3253** begins with "file:", then the filename is interpreted as a URI. ^URI
3254** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
3255** set in the third argument to sqlite3_open_v2(), or if it has
3256** been enabled globally using the [SQLITE_CONFIG_URI] option with the
3257** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
3258** URI filename interpretation is turned off
3259** by default, but future releases of SQLite might enable URI filename
3260** interpretation by default. See "[URI filenames]" for additional
3261** information.
3263** URI filenames are parsed according to RFC 3986. ^If the URI contains an
3264** authority, then it must be either an empty string or the string
3265** "localhost". ^If the authority is not an empty string or "localhost", an
3266** error is returned to the caller. ^The fragment component of a URI, if
3267** present, is ignored.
3269** ^SQLite uses the path component of the URI as the name of the disk file
3270** which contains the database. ^If the path begins with a '/' character,
3271** then it is interpreted as an absolute path. ^If the path does not begin
3272** with a '/' (meaning that the authority section is omitted from the URI)
3273** then the path is interpreted as a relative path.
3274** ^(On windows, the first component of an absolute path
3275** is a drive specification (e.g. "C:").)^
3277** [[core URI query parameters]]
3278** The query component of a URI may contain parameters that are interpreted
3279** either by SQLite itself, or by a [VFS | custom VFS implementation].
3280** SQLite and its built-in [VFSes] interpret the
3281** following query parameters:
3283** <ul>
3284** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
3285** a VFS object that provides the operating system interface that should
3286** be used to access the database file on disk. ^If this option is set to
3287** an empty string the default VFS object is used. ^Specifying an unknown
3288** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
3289** present, then the VFS specified by the option takes precedence over
3290** the value passed as the fourth parameter to sqlite3_open_v2().
3292** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
3293** "rwc", or "memory". Attempting to set it to any other value is
3294** an error)^.
3295** ^If "ro" is specified, then the database is opened for read-only
3296** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
3297** third argument to sqlite3_open_v2(). ^If the mode option is set to
3298** "rw", then the database is opened for read-write (but not create)
3299** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
3300** been set. ^Value "rwc" is equivalent to setting both
3301** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
3302** set to "memory" then a pure [in-memory database] that never reads
3303** or writes from disk is used. ^It is an error to specify a value for
3304** the mode parameter that is less restrictive than that specified by
3305** the flags passed in the third parameter to sqlite3_open_v2().
3307** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
3308** "private". ^Setting it to "shared" is equivalent to setting the
3309** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
3310** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
3311** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
3312** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
3313** a URI filename, its value overrides any behavior requested by setting
3316** <li> <b>psow</b>: ^The psow parameter indicates whether or not the
3317** [powersafe overwrite] property does or does not apply to the
3318** storage media on which the database file resides.
3320** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
3321** which if set disables file locking in rollback journal modes. This
3322** is useful for accessing a database on a filesystem that does not
3323** support locking. Caution: Database corruption might result if two
3324** or more processes write to the same database and any one of those
3325** processes uses nolock=1.
3327** <li> <b>immutable</b>: ^The immutable parameter is a boolean query
3328** parameter that indicates that the database file is stored on
3329** read-only media. ^When immutable is set, SQLite assumes that the
3330** database file cannot be changed, even by a process with higher
3331** privilege, and so the database is opened read-only and all locking
3332** and change detection is disabled. Caution: Setting the immutable
3333** property on a database file that does in fact change can result
3334** in incorrect query results and/or [SQLITE_CORRUPT] errors.
3335** See also: [SQLITE_IOCAP_IMMUTABLE].
3337** </ul>
3339** ^Specifying an unknown parameter in the query component of a URI is not an
3340** error. Future versions of SQLite might understand additional query
3341** parameters. See "[query parameters with special meaning to SQLite]" for
3342** additional information.
3344** [[URI filename examples]] <h3>URI filename examples</h3>
3346** <table border="1" align=center cellpadding=5>
3347** <tr><th> URI filenames <th> Results
3348** <tr><td> file:data.db <td>
3349** Open the file "data.db" in the current directory.
3350** <tr><td> file:/home/fred/data.db<br>
3351** file:///home/fred/data.db <br>
3352** file://localhost/home/fred/data.db <br> <td>
3353** Open the database file "/home/fred/data.db".
3354** <tr><td> file://darkstar/home/fred/data.db <td>
3355** An error. "darkstar" is not a recognized authority.
3356** <tr><td style="white-space:nowrap">
3357** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
3358** <td> Windows only: Open the file "data.db" on fred's desktop on drive
3359** C:. Note that the %20 escaping in this example is not strictly
3360** necessary - space characters can be used literally
3361** in URI filenames.
3362** <tr><td> file:data.db?mode=ro&cache=private <td>
3363** Open file "data.db" in the current directory for read-only access.
3364** Regardless of whether or not shared-cache mode is enabled by
3365** default, use a private cache.
3366** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
3367** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
3368** that uses dot-files in place of posix advisory locking.
3369** <tr><td> file:data.db?mode=readonly <td>
3370** An error. "readonly" is not a valid option for the "mode" parameter.
3371** </table>
3373** ^URI hexadecimal escape sequences (%HH) are supported within the path and
3374** query components of a URI. A hexadecimal escape sequence consists of a
3375** percent sign - "%" - followed by exactly two hexadecimal digits
3376** specifying an octet value. ^Before the path or query components of a
3377** URI filename are interpreted, they are encoded using UTF-8 and all
3378** hexadecimal escape sequences replaced by a single byte containing the
3379** corresponding octet. If this process generates an invalid UTF-8 encoding,
3380** the results are undefined.
3382** <b>Note to Windows users:</b> The encoding used for the filename argument
3383** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
3384** codepage is currently defined. Filenames containing international
3385** characters must be converted to UTF-8 prior to passing them into
3386** sqlite3_open() or sqlite3_open_v2().
3388** <b>Note to Windows Runtime users:</b> The temporary directory must be set
3389** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
3390** features that require the use of temporary files may fail.
3392** See also: [sqlite3_temp_directory]
3394SQLITE_API int sqlite3_open(
3395 const char *filename, /* Database filename (UTF-8) */
3396 sqlite3 **ppDb /* OUT: SQLite db handle */
3398SQLITE_API int sqlite3_open16(
3399 const void *filename, /* Database filename (UTF-16) */
3400 sqlite3 **ppDb /* OUT: SQLite db handle */
3402SQLITE_API int sqlite3_open_v2(
3403 const char *filename, /* Database filename (UTF-8) */
3404 sqlite3 **ppDb, /* OUT: SQLite db handle */
3405 int flags, /* Flags */
3406 const char *zVfs /* Name of VFS module to use */
3410** CAPI3REF: Obtain Values For URI Parameters
3412** These are utility routines, useful to VFS implementations, that check
3413** to see if a database file was a URI that contained a specific query
3414** parameter, and if so obtains the value of that query parameter.
3416** If F is the database filename pointer passed into the xOpen() method of
3417** a VFS implementation when the flags parameter to xOpen() has one or
3418** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
3419** P is the name of the query parameter, then
3420** sqlite3_uri_parameter(F,P) returns the value of the P
3421** parameter if it exists or a NULL pointer if P does not appear as a
3422** query parameter on F. If P is a query parameter of F
3423** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3424** a pointer to an empty string.
3426** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3427** parameter and returns true (1) or false (0) according to the value
3428** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3429** value of query parameter P is one of "yes", "true", or "on" in any
3430** case or if the value begins with a non-zero number. The
3431** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3432** query parameter P is one of "no", "false", or "off" in any case or
3433** if the value begins with a numeric zero. If P is not a query
3434** parameter on F or if the value of P is does not match any of the
3435** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3437** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3438** 64-bit signed integer and returns that integer, or D if P does not
3439** exist. If the value of P is something other than an integer, then
3440** zero is returned.
3442** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3443** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
3444** is not a database file pathname pointer that SQLite passed into the xOpen
3445** VFS method, then the behavior of this routine is undefined and probably
3446** undesirable.
3448** See the [URI filename] documentation for additional information.
3450SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3451SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3452SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3456** CAPI3REF: Error Codes And Messages
3457** METHOD: sqlite3
3459** ^If the most recent sqlite3_* API call associated with
3460** [database connection] D failed, then the sqlite3_errcode(D) interface
3461** returns the numeric [result code] or [extended result code] for that
3462** API call.
3463** ^The sqlite3_extended_errcode()
3464** interface is the same except that it always returns the
3465** [extended result code] even when extended result codes are
3466** disabled.
3468** The values returned by sqlite3_errcode() and/or
3469** sqlite3_extended_errcode() might change with each API call.
3470** Except, there are some interfaces that are guaranteed to never
3471** change the value of the error code. The error-code preserving
3472** interfaces are:
3474** <ul>
3475** <li> sqlite3_errcode()
3476** <li> sqlite3_extended_errcode()
3477** <li> sqlite3_errmsg()
3478** <li> sqlite3_errmsg16()
3479** </ul>
3481** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3482** text that describes the error, as either UTF-8 or UTF-16 respectively.
3483** ^(Memory to hold the error message string is managed internally.
3484** The application does not need to worry about freeing the result.
3485** However, the error string might be overwritten or deallocated by
3486** subsequent calls to other SQLite interface functions.)^
3488** ^The sqlite3_errstr() interface returns the English-language text
3489** that describes the [result code], as UTF-8.
3490** ^(Memory to hold the error message string is managed internally
3491** and must not be freed by the application)^.
3493** When the serialized [threading mode] is in use, it might be the
3494** case that a second error occurs on a separate thread in between
3495** the time of the first error and the call to these interfaces.
3496** When that happens, the second error will be reported since these
3497** interfaces always report the most recent result. To avoid
3498** this, each thread can obtain exclusive use of the [database connection] D
3499** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3500** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3501** all calls to the interfaces listed here are completed.
3503** If an interface fails with SQLITE_MISUSE, that means the interface
3504** was invoked incorrectly by the application. In that case, the
3505** error code and message may or may not be set.
3507SQLITE_API int sqlite3_errcode(sqlite3 *db);
3508SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
3509SQLITE_API const char *sqlite3_errmsg(sqlite3*);
3510SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
3511SQLITE_API const char *sqlite3_errstr(int);
3514** CAPI3REF: Prepared Statement Object
3515** KEYWORDS: {prepared statement} {prepared statements}
3517** An instance of this object represents a single SQL statement that
3518** has been compiled into binary form and is ready to be evaluated.
3520** Think of each SQL statement as a separate computer program. The
3521** original SQL text is source code. A prepared statement object
3522** is the compiled object code. All SQL must be converted into a
3523** prepared statement before it can be run.
3525** The life-cycle of a prepared statement object usually goes like this:
3527** <ol>
3528** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
3529** <li> Bind values to [parameters] using the sqlite3_bind_*()
3530** interfaces.
3531** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3532** <li> Reset the prepared statement using [sqlite3_reset()] then go back
3533** to step 2. Do this zero or more times.
3534** <li> Destroy the object using [sqlite3_finalize()].
3535** </ol>
3537typedef struct sqlite3_stmt sqlite3_stmt;
3540** CAPI3REF: Run-time Limits
3541** METHOD: sqlite3
3543** ^(This interface allows the size of various constructs to be limited
3544** on a connection by connection basis. The first parameter is the
3545** [database connection] whose limit is to be set or queried. The
3546** second parameter is one of the [limit categories] that define a
3547** class of constructs to be size limited. The third parameter is the
3548** new limit for that construct.)^
3550** ^If the new limit is a negative number, the limit is unchanged.
3551** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3552** [limits | hard upper bound]
3553** set at compile-time by a C preprocessor macro called
3554** [limits | SQLITE_MAX_<i>NAME</i>].
3555** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3556** ^Attempts to increase a limit above its hard upper bound are
3557** silently truncated to the hard upper bound.
3559** ^Regardless of whether or not the limit was changed, the
3560** [sqlite3_limit()] interface returns the prior value of the limit.
3561** ^Hence, to find the current value of a limit without changing it,
3562** simply invoke this interface with the third parameter set to -1.
3564** Run-time limits are intended for use in applications that manage
3565** both their own internal database and also databases that are controlled
3566** by untrusted external sources. An example application might be a
3567** web browser that has its own databases for storing history and
3568** separate databases controlled by JavaScript applications downloaded
3569** off the Internet. The internal databases can be given the
3570** large, default limits. Databases managed by external sources can
3571** be given much smaller limits designed to prevent a denial of service
3572** attack. Developers might also want to use the [sqlite3_set_authorizer()]
3573** interface to further control untrusted SQL. The size of the database
3574** created by an untrusted script can be contained using the
3575** [max_page_count] [PRAGMA].
3577** New run-time limit categories may be added in future releases.
3579SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
3582** CAPI3REF: Run-Time Limit Categories
3583** KEYWORDS: {limit category} {*limit categories}
3585** These constants define various performance limits
3586** that can be lowered at run-time using [sqlite3_limit()].
3587** The synopsis of the meanings of the various limits is shown below.
3588** Additional information is available at [limits | Limits in SQLite].
3590** <dl>
3592** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3595** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3598** <dd>The maximum number of columns in a table definition or in the
3599** result set of a [SELECT] or the maximum number of columns in an index
3600** or in an ORDER BY or GROUP BY clause.</dd>)^
3603** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3606** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3609** <dd>The maximum number of instructions in a virtual machine program
3610** used to implement an SQL statement. If [sqlite3_prepare_v2()] or
3611** the equivalent tries to allocate space for more than this many opcodes
3612** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
3615** <dd>The maximum number of arguments on a function.</dd>)^
3618** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3622** <dd>The maximum length of the pattern argument to the [LIKE] or
3623** [GLOB] operators.</dd>)^
3627** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3630** <dd>The maximum depth of recursion for triggers.</dd>)^
3633** <dd>The maximum number of auxiliary worker threads that a single
3634** [prepared statement] may start.</dd>)^
3635** </dl>
3642#define SQLITE_LIMIT_VDBE_OP 5
3651** CAPI3REF: Prepare Flags
3653** These constants define various flags that can be passed into
3654** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
3655** [sqlite3_prepare16_v3()] interfaces.
3657** New flags may be added in future releases of SQLite.
3659** <dl>
3661** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
3662** that the prepared statement will be retained for a long time and
3663** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
3664** and [sqlite3_prepare16_v3()] assume that the prepared statement will
3665** be used just once or at most a few times and then destroyed using
3666** [sqlite3_finalize()] relatively soon. The current implementation acts
3667** on this hint by avoiding the use of [lookaside memory] so as not to
3668** deplete the limited store of lookaside memory. Future versions of
3669** SQLite may act on this hint differently.
3672** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
3673** to be required for any prepared statement that wanted to use the
3674** [sqlite3_normalized_sql()] interface. However, the
3675** [sqlite3_normalized_sql()] interface is now available to all
3676** prepared statements, regardless of whether or not they use this
3677** flag.
3680** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
3681** to return an error (error code SQLITE_ERROR) if the statement uses
3682** any virtual tables.
3683** </dl>
3687#define SQLITE_PREPARE_NO_VTAB 0x04
3690** CAPI3REF: Compiling An SQL Statement
3691** KEYWORDS: {SQL statement compiler}
3692** METHOD: sqlite3
3693** CONSTRUCTOR: sqlite3_stmt
3695** To execute an SQL statement, it must first be compiled into a byte-code
3696** program using one of these routines. Or, in other words, these routines
3697** are constructors for the [prepared statement] object.
3699** The preferred routine to use is [sqlite3_prepare_v2()]. The
3700** [sqlite3_prepare()] interface is legacy and should be avoided.
3701** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
3702** for special purposes.
3704** The use of the UTF-8 interfaces is preferred, as SQLite currently
3705** does all parsing using UTF-8. The UTF-16 interfaces are provided
3706** as a convenience. The UTF-16 interfaces work by converting the
3707** input text into UTF-8, then invoking the corresponding UTF-8 interface.
3709** The first argument, "db", is a [database connection] obtained from a
3710** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3711** [sqlite3_open16()]. The database connection must not have been closed.
3713** The second argument, "zSql", is the statement to be compiled, encoded
3714** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(),
3715** and sqlite3_prepare_v3()
3716** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
3717** and sqlite3_prepare16_v3() use UTF-16.
3719** ^If the nByte argument is negative, then zSql is read up to the
3720** first zero terminator. ^If nByte is positive, then it is the
3721** number of bytes read from zSql. ^If nByte is zero, then no prepared
3722** statement is generated.
3723** If the caller knows that the supplied string is nul-terminated, then
3724** there is a small performance advantage to passing an nByte parameter that
3725** is the number of bytes in the input string <i>including</i>
3726** the nul-terminator.
3728** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3729** past the end of the first SQL statement in zSql. These routines only
3730** compile the first statement in zSql, so *pzTail is left pointing to
3731** what remains uncompiled.
3733** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3734** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
3735** to NULL. ^If the input text contains no SQL (if the input is an empty
3736** string or a comment) then *ppStmt is set to NULL.
3737** The calling procedure is responsible for deleting the compiled
3738** SQL statement using [sqlite3_finalize()] after it has finished with it.
3739** ppStmt may not be NULL.
3741** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3742** otherwise an [error code] is returned.
3744** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
3745** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
3746** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
3747** are retained for backwards compatibility, but their use is discouraged.
3748** ^In the "vX" interfaces, the prepared statement
3749** that is returned (the [sqlite3_stmt] object) contains a copy of the
3750** original SQL text. This causes the [sqlite3_step()] interface to
3751** behave differently in three ways:
3753** <ol>
3754** <li>
3755** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3756** always used to do, [sqlite3_step()] will automatically recompile the SQL
3757** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3758** retries will occur before sqlite3_step() gives up and returns an error.
3759** </li>
3761** <li>
3762** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3763** [error codes] or [extended error codes]. ^The legacy behavior was that
3764** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3765** and the application would have to make a second call to [sqlite3_reset()]
3766** in order to find the underlying cause of the problem. With the "v2" prepare
3767** interfaces, the underlying reason for the error is returned immediately.
3768** </li>
3770** <li>
3771** ^If the specific value bound to [parameter | host parameter] in the
3772** WHERE clause might influence the choice of query plan for a statement,
3773** then the statement will be automatically recompiled, as if there had been
3774** a schema change, on the first [sqlite3_step()] call following any change
3775** to the [sqlite3_bind_text | bindings] of that [parameter].
3776** ^The specific value of WHERE-clause [parameter] might influence the
3777** choice of query plan if the parameter is the left-hand side of a [LIKE]
3778** or [GLOB] operator or if the parameter is compared to an indexed column
3779** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3780** </li>
3781** </ol>
3783** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
3784** the extra prepFlags parameter, which is a bit array consisting of zero or
3785** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The
3786** sqlite3_prepare_v2() interface works exactly the same as
3787** sqlite3_prepare_v3() with a zero prepFlags parameter.
3789SQLITE_API int sqlite3_prepare(
3790 sqlite3 *db, /* Database handle */
3791 const char *zSql, /* SQL statement, UTF-8 encoded */
3792 int nByte, /* Maximum length of zSql in bytes. */
3793 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3794 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3796SQLITE_API int sqlite3_prepare_v2(
3797 sqlite3 *db, /* Database handle */
3798 const char *zSql, /* SQL statement, UTF-8 encoded */
3799 int nByte, /* Maximum length of zSql in bytes. */
3800 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3801 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3803SQLITE_API int sqlite3_prepare_v3(
3804 sqlite3 *db, /* Database handle */
3805 const char *zSql, /* SQL statement, UTF-8 encoded */
3806 int nByte, /* Maximum length of zSql in bytes. */
3807 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
3808 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3809 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3811SQLITE_API int sqlite3_prepare16(
3812 sqlite3 *db, /* Database handle */
3813 const void *zSql, /* SQL statement, UTF-16 encoded */
3814 int nByte, /* Maximum length of zSql in bytes. */
3815 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3816 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3818SQLITE_API int sqlite3_prepare16_v2(
3819 sqlite3 *db, /* Database handle */
3820 const void *zSql, /* SQL statement, UTF-16 encoded */
3821 int nByte, /* Maximum length of zSql in bytes. */
3822 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3823 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3825SQLITE_API int sqlite3_prepare16_v3(
3826 sqlite3 *db, /* Database handle */
3827 const void *zSql, /* SQL statement, UTF-16 encoded */
3828 int nByte, /* Maximum length of zSql in bytes. */
3829 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
3830 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3831 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3835** CAPI3REF: Retrieving Statement SQL
3836** METHOD: sqlite3_stmt
3838** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
3839** SQL text used to create [prepared statement] P if P was
3840** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
3841** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
3842** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
3843** string containing the SQL text of prepared statement P with
3844** [bound parameters] expanded.
3845** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
3846** string containing the normalized SQL text of prepared statement P. The
3847** semantics used to normalize a SQL statement are unspecified and subject
3848** to change. At a minimum, literal values will be replaced with suitable
3849** placeholders.
3851** ^(For example, if a prepared statement is created using the SQL
3852** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
3853** and parameter :xyz is unbound, then sqlite3_sql() will return
3854** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
3855** will return "SELECT 2345,NULL".)^
3857** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
3858** is available to hold the result, or if the result would exceed the
3859** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
3861** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
3862** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time
3863** option causes sqlite3_expanded_sql() to always return NULL.
3865** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
3866** are managed by SQLite and are automatically freed when the prepared
3867** statement is finalized.
3868** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
3869** is obtained from [sqlite3_malloc()] and must be free by the application
3870** by passing it to [sqlite3_free()].
3872SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
3873SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
3874SQLITE_API const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
3877** CAPI3REF: Determine If An SQL Statement Writes The Database
3878** METHOD: sqlite3_stmt
3880** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3881** and only if the [prepared statement] X makes no direct changes to
3882** the content of the database file.
3884** Note that [application-defined SQL functions] or
3885** [virtual tables] might change the database indirectly as a side effect.
3886** ^(For example, if an application defines a function "eval()" that
3887** calls [sqlite3_exec()], then the following SQL statement would
3888** change the database file through side-effects:
3890** <blockquote><pre>
3891** SELECT eval('DELETE FROM t1') FROM t2;
3892** </pre></blockquote>
3894** But because the [SELECT] statement does not change the database file
3895** directly, sqlite3_stmt_readonly() would still return true.)^
3897** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3898** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3899** since the statements themselves do not actually modify the database but
3900** rather they control the timing of when other statements modify the
3901** database. ^The [ATTACH] and [DETACH] statements also cause
3902** sqlite3_stmt_readonly() to return true since, while those statements
3903** change the configuration of a database connection, they do not make
3904** changes to the content of the database files on disk.
3905** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
3906** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
3907** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
3908** sqlite3_stmt_readonly() returns false for those commands.
3910SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3913** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement
3914** METHOD: sqlite3_stmt
3916** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the
3917** prepared statement S is an EXPLAIN statement, or 2 if the
3918** statement S is an EXPLAIN QUERY PLAN.
3919** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is
3920** an ordinary statement or a NULL pointer.
3922SQLITE_API int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);
3925** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3926** METHOD: sqlite3_stmt
3928** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3929** [prepared statement] S has been stepped at least once using
3930** [sqlite3_step(S)] but has neither run to completion (returned
3931** [SQLITE_DONE] from [sqlite3_step(S)]) nor
3932** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
3933** interface returns false if S is a NULL pointer. If S is not a
3934** NULL pointer and is not a pointer to a valid [prepared statement]
3935** object, then the behavior is undefined and probably undesirable.
3937** This interface can be used in combination [sqlite3_next_stmt()]
3938** to locate all prepared statements associated with a database
3939** connection that are in need of being reset. This can be used,
3940** for example, in diagnostic routines to search for prepared
3941** statements that are holding a transaction open.
3943SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
3946** CAPI3REF: Dynamically Typed Value Object
3947** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3949** SQLite uses the sqlite3_value object to represent all values
3950** that can be stored in a database table. SQLite uses dynamic typing
3951** for the values it stores. ^Values stored in sqlite3_value objects
3952** can be integers, floating point values, strings, BLOBs, or NULL.
3954** An sqlite3_value object may be either "protected" or "unprotected".
3955** Some interfaces require a protected sqlite3_value. Other interfaces
3956** will accept either a protected or an unprotected sqlite3_value.
3957** Every interface that accepts sqlite3_value arguments specifies
3958** whether or not it requires a protected sqlite3_value. The
3959** [sqlite3_value_dup()] interface can be used to construct a new
3960** protected sqlite3_value from an unprotected sqlite3_value.
3962** The terms "protected" and "unprotected" refer to whether or not
3963** a mutex is held. An internal mutex is held for a protected
3964** sqlite3_value object but no mutex is held for an unprotected
3965** sqlite3_value object. If SQLite is compiled to be single-threaded
3966** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3967** or if SQLite is run in one of reduced mutex modes
3969** then there is no distinction between protected and unprotected
3970** sqlite3_value objects and they can be used interchangeably. However,
3971** for maximum code portability it is recommended that applications
3972** still make the distinction between protected and unprotected
3973** sqlite3_value objects even when not strictly required.
3975** ^The sqlite3_value objects that are passed as parameters into the
3976** implementation of [application-defined SQL functions] are protected.
3977** ^The sqlite3_value object returned by
3978** [sqlite3_column_value()] is unprotected.
3979** Unprotected sqlite3_value objects may only be used as arguments
3980** to [sqlite3_result_value()], [sqlite3_bind_value()], and
3981** [sqlite3_value_dup()].
3982** The [sqlite3_value_blob | sqlite3_value_type()] family of
3983** interfaces require protected sqlite3_value objects.
3985typedef struct sqlite3_value sqlite3_value;
3988** CAPI3REF: SQL Function Context Object
3990** The context in which an SQL function executes is stored in an
3991** sqlite3_context object. ^A pointer to an sqlite3_context object
3992** is always first parameter to [application-defined SQL functions].
3993** The application-defined SQL function implementation will pass this
3994** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3995** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3996** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3997** and/or [sqlite3_set_auxdata()].
3999typedef struct sqlite3_context sqlite3_context;
4002** CAPI3REF: Binding Values To Prepared Statements
4003** KEYWORDS: {host parameter} {host parameters} {host parameter name}
4004** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
4005** METHOD: sqlite3_stmt
4007** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
4008** literals may be replaced by a [parameter] that matches one of following
4009** templates:
4011** <ul>
4012** <li> ?
4013** <li> ?NNN
4014** <li> :VVV
4015** <li> @VVV
4016** <li> $VVV
4017** </ul>
4019** In the templates above, NNN represents an integer literal,
4020** and VVV represents an alphanumeric identifier.)^ ^The values of these
4021** parameters (also called "host parameter names" or "SQL parameters")
4022** can be set using the sqlite3_bind_*() routines defined here.
4024** ^The first argument to the sqlite3_bind_*() routines is always
4025** a pointer to the [sqlite3_stmt] object returned from
4026** [sqlite3_prepare_v2()] or its variants.
4028** ^The second argument is the index of the SQL parameter to be set.
4029** ^The leftmost SQL parameter has an index of 1. ^When the same named
4030** SQL parameter is used more than once, second and subsequent
4031** occurrences have the same index as the first occurrence.
4032** ^The index for named parameters can be looked up using the
4033** [sqlite3_bind_parameter_index()] API if desired. ^The index
4034** for "?NNN" parameters is the value of NNN.
4035** ^The NNN value must be between 1 and the [sqlite3_limit()]
4036** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
4038** ^The third argument is the value to bind to the parameter.
4039** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4040** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
4041** is ignored and the end result is the same as sqlite3_bind_null().
4043** ^(In those routines that have a fourth argument, its value is the
4044** number of bytes in the parameter. To be clear: the value is the
4045** number of <u>bytes</u> in the value, not the number of characters.)^
4046** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4047** is negative, then the length of the string is
4048** the number of bytes up to the first zero terminator.
4049** If the fourth parameter to sqlite3_bind_blob() is negative, then
4050** the behavior is undefined.
4051** If a non-negative fourth parameter is provided to sqlite3_bind_text()
4052** or sqlite3_bind_text16() or sqlite3_bind_text64() then
4053** that parameter must be the byte offset
4054** where the NUL terminator would occur assuming the string were NUL
4055** terminated. If any NUL characters occur at byte offsets less than
4056** the value of the fourth parameter then the resulting string value will
4057** contain embedded NULs. The result of expressions involving strings
4058** with embedded NULs is undefined.
4060** ^The fifth argument to the BLOB and string binding interfaces
4061** is a destructor used to dispose of the BLOB or
4062** string after SQLite has finished with it. ^The destructor is called
4063** to dispose of the BLOB or string even if the call to the bind API fails,
4064** except the destructor is not called if the third parameter is a NULL
4065** pointer or the fourth parameter is negative.
4066** ^If the fifth argument is
4067** the special value [SQLITE_STATIC], then SQLite assumes that the
4068** information is in static, unmanaged space and does not need to be freed.
4069** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
4070** SQLite makes its own private copy of the data immediately, before
4071** the sqlite3_bind_*() routine returns.
4073** ^The sixth argument to sqlite3_bind_text64() must be one of
4075** to specify the encoding of the text in the third parameter. If
4076** the sixth argument to sqlite3_bind_text64() is not one of the
4077** allowed values shown above, or if the text encoding is different
4078** from the encoding specified by the sixth parameter, then the behavior
4079** is undefined.
4081** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
4082** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
4083** (just an integer to hold its size) while it is being processed.
4084** Zeroblobs are intended to serve as placeholders for BLOBs whose
4085** content is later written using
4086** [sqlite3_blob_open | incremental BLOB I/O] routines.
4087** ^A negative value for the zeroblob results in a zero-length BLOB.
4089** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
4090** [prepared statement] S to have an SQL value of NULL, but to also be
4091** associated with the pointer P of type T. ^D is either a NULL pointer or
4092** a pointer to a destructor function for P. ^SQLite will invoke the
4093** destructor D with a single argument of P when it is finished using
4094** P. The T parameter should be a static string, preferably a string
4095** literal. The sqlite3_bind_pointer() routine is part of the
4096** [pointer passing interface] added for SQLite 3.20.0.
4098** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
4099** for the [prepared statement] or with a prepared statement for which
4100** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
4101** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
4102** routine is passed a [prepared statement] that has been finalized, the
4103** result is undefined and probably harmful.
4105** ^Bindings are not cleared by the [sqlite3_reset()] routine.
4106** ^Unbound parameters are interpreted as NULL.
4108** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
4109** [error code] if anything goes wrong.
4110** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
4111** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
4113** ^[SQLITE_RANGE] is returned if the parameter
4114** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
4116** See also: [sqlite3_bind_parameter_count()],
4117** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
4119SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
4120SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
4121 void(*)(void*));
4122SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
4123SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
4124SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
4125SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
4126SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
4127SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
4128SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
4129 void(*)(void*), unsigned char encoding);
4130SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
4131SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
4132SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
4133SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
4136** CAPI3REF: Number Of SQL Parameters
4137** METHOD: sqlite3_stmt
4139** ^This routine can be used to find the number of [SQL parameters]
4140** in a [prepared statement]. SQL parameters are tokens of the
4141** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
4142** placeholders for values that are [sqlite3_bind_blob | bound]
4143** to the parameters at a later time.
4145** ^(This routine actually returns the index of the largest (rightmost)
4146** parameter. For all forms except ?NNN, this will correspond to the
4147** number of unique parameters. If parameters of the ?NNN form are used,
4148** there may be gaps in the list.)^
4150** See also: [sqlite3_bind_blob|sqlite3_bind()],
4151** [sqlite3_bind_parameter_name()], and
4152** [sqlite3_bind_parameter_index()].
4154SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
4157** CAPI3REF: Name Of A Host Parameter
4158** METHOD: sqlite3_stmt
4160** ^The sqlite3_bind_parameter_name(P,N) interface returns
4161** the name of the N-th [SQL parameter] in the [prepared statement] P.
4162** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
4163** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
4164** respectively.
4165** In other words, the initial ":" or "$" or "@" or "?"
4166** is included as part of the name.)^
4167** ^Parameters of the form "?" without a following integer have no name
4168** and are referred to as "nameless" or "anonymous parameters".
4170** ^The first host parameter has an index of 1, not 0.
4172** ^If the value N is out of range or if the N-th parameter is
4173** nameless, then NULL is returned. ^The returned string is
4174** always in UTF-8 encoding even if the named parameter was
4175** originally specified as UTF-16 in [sqlite3_prepare16()],
4176** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4178** See also: [sqlite3_bind_blob|sqlite3_bind()],
4179** [sqlite3_bind_parameter_count()], and
4180** [sqlite3_bind_parameter_index()].
4182SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
4185** CAPI3REF: Index Of A Parameter With A Given Name
4186** METHOD: sqlite3_stmt
4188** ^Return the index of an SQL parameter given its name. ^The
4189** index value returned is suitable for use as the second
4190** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
4191** is returned if no matching parameter is found. ^The parameter
4192** name must be given in UTF-8 even if the original statement
4193** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
4194** [sqlite3_prepare16_v3()].
4196** See also: [sqlite3_bind_blob|sqlite3_bind()],
4197** [sqlite3_bind_parameter_count()], and
4198** [sqlite3_bind_parameter_name()].
4200SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
4203** CAPI3REF: Reset All Bindings On A Prepared Statement
4204** METHOD: sqlite3_stmt
4206** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
4207** the [sqlite3_bind_blob | bindings] on a [prepared statement].
4208** ^Use this routine to reset all host parameters to NULL.
4210SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
4213** CAPI3REF: Number Of Columns In A Result Set
4214** METHOD: sqlite3_stmt
4216** ^Return the number of columns in the result set returned by the
4217** [prepared statement]. ^If this routine returns 0, that means the
4218** [prepared statement] returns no data (for example an [UPDATE]).
4219** ^However, just because this routine returns a positive number does not
4220** mean that one or more rows of data will be returned. ^A SELECT statement
4221** will always have a positive sqlite3_column_count() but depending on the
4222** WHERE clause constraints and the table content, it might return no rows.
4224** See also: [sqlite3_data_count()]
4226SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
4229** CAPI3REF: Column Names In A Result Set
4230** METHOD: sqlite3_stmt
4232** ^These routines return the name assigned to a particular column
4233** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
4234** interface returns a pointer to a zero-terminated UTF-8 string
4235** and sqlite3_column_name16() returns a pointer to a zero-terminated
4236** UTF-16 string. ^The first parameter is the [prepared statement]
4237** that implements the [SELECT] statement. ^The second parameter is the
4238** column number. ^The leftmost column is number 0.
4240** ^The returned string pointer is valid until either the [prepared statement]
4241** is destroyed by [sqlite3_finalize()] or until the statement is automatically
4242** reprepared by the first call to [sqlite3_step()] for a particular run
4243** or until the next call to
4244** sqlite3_column_name() or sqlite3_column_name16() on the same column.
4246** ^If sqlite3_malloc() fails during the processing of either routine
4247** (for example during a conversion from UTF-8 to UTF-16) then a
4248** NULL pointer is returned.
4250** ^The name of a result column is the value of the "AS" clause for
4251** that column, if there is an AS clause. If there is no AS clause
4252** then the name of the column is unspecified and may change from
4253** one release of SQLite to the next.
4255SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
4256SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
4259** CAPI3REF: Source Of Data In A Query Result
4260** METHOD: sqlite3_stmt
4262** ^These routines provide a means to determine the database, table, and
4263** table column that is the origin of a particular result column in
4264** [SELECT] statement.
4265** ^The name of the database or table or column can be returned as
4266** either a UTF-8 or UTF-16 string. ^The _database_ routines return
4267** the database name, the _table_ routines return the table name, and
4268** the origin_ routines return the column name.
4269** ^The returned string is valid until the [prepared statement] is destroyed
4270** using [sqlite3_finalize()] or until the statement is automatically
4271** reprepared by the first call to [sqlite3_step()] for a particular run
4272** or until the same information is requested
4273** again in a different encoding.
4275** ^The names returned are the original un-aliased names of the
4276** database, table, and column.
4278** ^The first argument to these interfaces is a [prepared statement].
4279** ^These functions return information about the Nth result column returned by
4280** the statement, where N is the second function argument.
4281** ^The left-most column is column 0 for these routines.
4283** ^If the Nth column returned by the statement is an expression or
4284** subquery and is not a column value, then all of these functions return
4285** NULL. ^These routine might also return NULL if a memory allocation error
4286** occurs. ^Otherwise, they return the name of the attached database, table,
4287** or column that query result column was extracted from.
4289** ^As with all other SQLite APIs, those whose names end with "16" return
4290** UTF-16 encoded strings and the other functions return UTF-8.
4292** ^These APIs are only available if the library was compiled with the
4293** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
4295** If two or more threads call one or more of these routines against the same
4296** prepared statement and column at the same time then the results are
4297** undefined.
4299** If two or more threads call one or more
4300** [sqlite3_column_database_name | column metadata interfaces]
4301** for the same [prepared statement] and result column
4302** at the same time then the results are undefined.
4304SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
4305SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
4306SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
4307SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
4308SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
4309SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
4312** CAPI3REF: Declared Datatype Of A Query Result
4313** METHOD: sqlite3_stmt
4315** ^(The first parameter is a [prepared statement].
4316** If this statement is a [SELECT] statement and the Nth column of the
4317** returned result set of that [SELECT] is a table column (not an
4318** expression or subquery) then the declared type of the table
4319** column is returned.)^ ^If the Nth column of the result set is an
4320** expression or subquery, then a NULL pointer is returned.
4321** ^The returned string is always UTF-8 encoded.
4323** ^(For example, given the database schema:
4327** and the following statement to be compiled:
4329** SELECT c1 + 1, c1 FROM t1;
4331** this routine would return the string "VARIANT" for the second result
4332** column (i==1), and a NULL pointer for the first result column (i==0).)^
4334** ^SQLite uses dynamic run-time typing. ^So just because a column
4335** is declared to contain a particular type does not mean that the
4336** data stored in that column is of the declared type. SQLite is
4337** strongly typed, but the typing is dynamic not static. ^Type
4338** is associated with individual values, not with the containers
4339** used to hold those values.
4341SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
4342SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
4345** CAPI3REF: Evaluate An SQL Statement
4346** METHOD: sqlite3_stmt
4348** After a [prepared statement] has been prepared using any of
4349** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
4350** or [sqlite3_prepare16_v3()] or one of the legacy
4351** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
4352** must be called one or more times to evaluate the statement.
4354** The details of the behavior of the sqlite3_step() interface depend
4355** on whether the statement was prepared using the newer "vX" interfaces
4356** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
4357** [sqlite3_prepare16_v2()] or the older legacy
4358** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
4359** new "vX" interface is recommended for new applications but the legacy
4360** interface will continue to be supported.
4362** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
4364** ^With the "v2" interface, any of the other [result codes] or
4365** [extended result codes] might be returned as well.
4367** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
4368** database locks it needs to do its job. ^If the statement is a [COMMIT]
4369** or occurs outside of an explicit transaction, then you can retry the
4370** statement. If the statement is not a [COMMIT] and occurs within an
4371** explicit transaction then you should rollback the transaction before
4372** continuing.
4374** ^[SQLITE_DONE] means that the statement has finished executing
4375** successfully. sqlite3_step() should not be called again on this virtual
4376** machine without first calling [sqlite3_reset()] to reset the virtual
4377** machine back to its initial state.
4379** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
4380** is returned each time a new row of data is ready for processing by the
4381** caller. The values may be accessed using the [column access functions].
4382** sqlite3_step() is called again to retrieve the next row of data.
4384** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
4385** violation) has occurred. sqlite3_step() should not be called again on
4386** the VM. More information may be found by calling [sqlite3_errmsg()].
4387** ^With the legacy interface, a more specific error code (for example,
4389** can be obtained by calling [sqlite3_reset()] on the
4390** [prepared statement]. ^In the "v2" interface,
4391** the more specific error code is returned directly by sqlite3_step().
4393** [SQLITE_MISUSE] means that the this routine was called inappropriately.
4394** Perhaps it was called on a [prepared statement] that has
4395** already been [sqlite3_finalize | finalized] or on one that had
4396** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
4397** be the case that the same database connection is being used by two or
4398** more threads at the same moment in time.
4400** For all versions of SQLite up to and including, a call to
4401** [sqlite3_reset()] was required after sqlite3_step() returned anything
4402** other than [SQLITE_ROW] before any subsequent invocation of
4403** sqlite3_step(). Failure to reset the prepared statement using
4404** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
4405** sqlite3_step(). But after [version] ([dateof:],
4406** sqlite3_step() began
4407** calling [sqlite3_reset()] automatically in this circumstance rather
4408** than returning [SQLITE_MISUSE]. This is not considered a compatibility
4409** break because any application that ever receives an SQLITE_MISUSE error
4410** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
4411** can be used to restore the legacy behavior.
4413** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
4414** API always returns a generic error code, [SQLITE_ERROR], following any
4415** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
4416** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
4417** specific [error codes] that better describes the error.
4418** We admit that this is a goofy design. The problem has been fixed
4419** with the "v2" interface. If you prepare all of your SQL statements
4420** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
4421** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
4422** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
4423** then the more specific [error codes] are returned directly
4424** by sqlite3_step(). The use of the "vX" interfaces is recommended.
4426SQLITE_API int sqlite3_step(sqlite3_stmt*);
4429** CAPI3REF: Number of columns in a result set
4430** METHOD: sqlite3_stmt
4432** ^The sqlite3_data_count(P) interface returns the number of columns in the
4433** current row of the result set of [prepared statement] P.
4434** ^If prepared statement P does not have results ready to return
4435** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
4436** interfaces) then sqlite3_data_count(P) returns 0.
4437** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
4438** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
4439** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
4440** will return non-zero if previous call to [sqlite3_step](P) returned
4441** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
4442** where it always returns zero since each step of that multi-step
4443** pragma returns 0 columns of data.
4445** See also: [sqlite3_column_count()]
4447SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
4450** CAPI3REF: Fundamental Datatypes
4453** ^(Every value in SQLite has one of five fundamental datatypes:
4455** <ul>
4456** <li> 64-bit signed integer
4457** <li> 64-bit IEEE floating point number
4458** <li> string
4459** <li> BLOB
4460** <li> NULL
4461** </ul>)^
4463** These constants are codes for each of those types.
4465** Note that the SQLITE_TEXT constant was also used in SQLite version 2
4466** for a completely different meaning. Software that links against both
4467** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
4470#define SQLITE_INTEGER 1
4471#define SQLITE_FLOAT 2
4472#define SQLITE_BLOB 4
4473#define SQLITE_NULL 5
4474#ifdef SQLITE_TEXT
4475# undef SQLITE_TEXT
4477# define SQLITE_TEXT 3
4479#define SQLITE3_TEXT 3
4482** CAPI3REF: Result Values From A Query
4483** KEYWORDS: {column access functions}
4484** METHOD: sqlite3_stmt
4486** <b>Summary:</b>
4487** <blockquote><table border=0 cellpadding=0 cellspacing=0>
4488** <tr><td><b>sqlite3_column_blob</b><td>&rarr;<td>BLOB result
4489** <tr><td><b>sqlite3_column_double</b><td>&rarr;<td>REAL result
4490** <tr><td><b>sqlite3_column_int</b><td>&rarr;<td>32-bit INTEGER result
4491** <tr><td><b>sqlite3_column_int64</b><td>&rarr;<td>64-bit INTEGER result
4492** <tr><td><b>sqlite3_column_text</b><td>&rarr;<td>UTF-8 TEXT result
4493** <tr><td><b>sqlite3_column_text16</b><td>&rarr;<td>UTF-16 TEXT result
4494** <tr><td><b>sqlite3_column_value</b><td>&rarr;<td>The result as an
4495** [sqlite3_value|unprotected sqlite3_value] object.
4496** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
4497** <tr><td><b>sqlite3_column_bytes</b><td>&rarr;<td>Size of a BLOB
4498** or a UTF-8 TEXT result in bytes
4499** <tr><td><b>sqlite3_column_bytes16&nbsp;&nbsp;</b>
4500** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
4501** TEXT in bytes
4502** <tr><td><b>sqlite3_column_type</b><td>&rarr;<td>Default
4503** datatype of the result
4504** </table></blockquote>
4506** <b>Details:</b>
4508** ^These routines return information about a single column of the current
4509** result row of a query. ^In every case the first argument is a pointer
4510** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
4511** that was returned from [sqlite3_prepare_v2()] or one of its variants)
4512** and the second argument is the index of the column for which information
4513** should be returned. ^The leftmost column of the result set has the index 0.
4514** ^The number of columns in the result can be determined using
4515** [sqlite3_column_count()].
4517** If the SQL statement does not currently point to a valid row, or if the
4518** column index is out of range, the result is undefined.
4519** These routines may only be called when the most recent call to
4520** [sqlite3_step()] has returned [SQLITE_ROW] and neither
4521** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
4522** If any of these routines are called after [sqlite3_reset()] or
4523** [sqlite3_finalize()] or after [sqlite3_step()] has returned
4524** something other than [SQLITE_ROW], the results are undefined.
4525** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
4526** are called from a different thread while any of these routines
4527** are pending, then the results are undefined.
4529** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
4530** each return the value of a result column in a specific data format. If
4531** the result column is not initially in the requested format (for example,
4532** if the query returns an integer but the sqlite3_column_text() interface
4533** is used to extract the value) then an automatic type conversion is performed.
4535** ^The sqlite3_column_type() routine returns the
4536** [SQLITE_INTEGER | datatype code] for the initial data type
4537** of the result column. ^The returned value is one of [SQLITE_INTEGER],
4539** The return value of sqlite3_column_type() can be used to decide which
4540** of the first six interface should be used to extract the column value.
4541** The value returned by sqlite3_column_type() is only meaningful if no
4542** automatic type conversions have occurred for the value in question.
4543** After a type conversion, the result of calling sqlite3_column_type()
4544** is undefined, though harmless. Future
4545** versions of SQLite may change the behavior of sqlite3_column_type()
4546** following a type conversion.
4548** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
4549** or sqlite3_column_bytes16() interfaces can be used to determine the size
4550** of that BLOB or string.
4552** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
4553** routine returns the number of bytes in that BLOB or string.
4554** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
4555** the string to UTF-8 and then returns the number of bytes.
4556** ^If the result is a numeric value then sqlite3_column_bytes() uses
4557** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
4558** the number of bytes in that string.
4559** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
4561** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
4562** routine returns the number of bytes in that BLOB or string.
4563** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
4564** the string to UTF-16 and then returns the number of bytes.
4565** ^If the result is a numeric value then sqlite3_column_bytes16() uses
4566** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
4567** the number of bytes in that string.
4568** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
4570** ^The values returned by [sqlite3_column_bytes()] and
4571** [sqlite3_column_bytes16()] do not include the zero terminators at the end
4572** of the string. ^For clarity: the values returned by
4573** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
4574** bytes in the string, not the number of characters.
4576** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
4577** even empty strings, are always zero-terminated. ^The return
4578** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
4580** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
4581** [unprotected sqlite3_value] object. In a multithreaded environment,
4582** an unprotected sqlite3_value object may only be used safely with
4583** [sqlite3_bind_value()] and [sqlite3_result_value()].
4584** If the [unprotected sqlite3_value] object returned by
4585** [sqlite3_column_value()] is used in any other way, including calls
4586** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
4587** or [sqlite3_value_bytes()], the behavior is not threadsafe.
4588** Hence, the sqlite3_column_value() interface
4589** is normally only useful within the implementation of
4590** [application-defined SQL functions] or [virtual tables], not within
4591** top-level application code.
4593** The these routines may attempt to convert the datatype of the result.
4594** ^For example, if the internal representation is FLOAT and a text result
4595** is requested, [sqlite3_snprintf()] is used internally to perform the
4596** conversion automatically. ^(The following table details the conversions
4597** that are applied:
4599** <blockquote>
4600** <table border="1">
4601** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
4603** <tr><td> NULL <td> INTEGER <td> Result is 0
4604** <tr><td> NULL <td> FLOAT <td> Result is 0.0
4605** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer
4606** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer
4607** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
4608** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
4609** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
4610** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER
4611** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
4612** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB
4613** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER
4614** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL
4615** <tr><td> TEXT <td> BLOB <td> No change
4616** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER
4617** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL
4618** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
4619** </table>
4620** </blockquote>)^
4622** Note that when type conversions occur, pointers returned by prior
4623** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
4624** sqlite3_column_text16() may be invalidated.
4625** Type conversions and pointer invalidations might occur
4626** in the following cases:
4628** <ul>
4629** <li> The initial content is a BLOB and sqlite3_column_text() or
4630** sqlite3_column_text16() is called. A zero-terminator might
4631** need to be added to the string.</li>
4632** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
4633** sqlite3_column_text16() is called. The content must be converted
4634** to UTF-16.</li>
4635** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
4636** sqlite3_column_text() is called. The content must be converted
4637** to UTF-8.</li>
4638** </ul>
4640** ^Conversions between UTF-16be and UTF-16le are always done in place and do
4641** not invalidate a prior pointer, though of course the content of the buffer
4642** that the prior pointer references will have been modified. Other kinds
4643** of conversion are done in place when it is possible, but sometimes they
4644** are not possible and in those cases prior pointers are invalidated.
4646** The safest policy is to invoke these routines
4647** in one of the following ways:
4649** <ul>
4650** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
4651** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
4652** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
4653** </ul>
4655** In other words, you should call sqlite3_column_text(),
4656** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
4657** into the desired format, then invoke sqlite3_column_bytes() or
4658** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
4659** to sqlite3_column_text() or sqlite3_column_blob() with calls to
4660** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
4661** with calls to sqlite3_column_bytes().
4663** ^The pointers returned are valid until a type conversion occurs as
4664** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
4665** [sqlite3_finalize()] is called. ^The memory space used to hold strings
4666** and BLOBs is freed automatically. Do not pass the pointers returned
4667** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
4668** [sqlite3_free()].
4670** As long as the input parameters are correct, these routines will only
4671** fail if an out-of-memory error occurs during a format conversion.
4672** Only the following subset of interfaces are subject to out-of-memory
4673** errors:
4675** <ul>
4676** <li> sqlite3_column_blob()
4677** <li> sqlite3_column_text()
4678** <li> sqlite3_column_text16()
4679** <li> sqlite3_column_bytes()
4680** <li> sqlite3_column_bytes16()
4681** </ul>
4683** If an out-of-memory error occurs, then the return value from these
4684** routines is the same as if the column had contained an SQL NULL value.
4685** Valid SQL NULL returns can be distinguished from out-of-memory errors
4686** by invoking the [sqlite3_errcode()] immediately after the suspect
4687** return value is obtained and before any
4688** other SQLite interface is called on the same [database connection].
4690SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
4691SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
4692SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
4693SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
4694SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
4695SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
4696SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
4697SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
4698SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
4699SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
4702** CAPI3REF: Destroy A Prepared Statement Object
4703** DESTRUCTOR: sqlite3_stmt
4705** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4706** ^If the most recent evaluation of the statement encountered no errors
4707** or if the statement is never been evaluated, then sqlite3_finalize() returns
4708** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
4709** sqlite3_finalize(S) returns the appropriate [error code] or
4710** [extended error code].
4712** ^The sqlite3_finalize(S) routine can be called at any point during
4713** the life cycle of [prepared statement] S:
4714** before statement S is ever evaluated, after
4715** one or more calls to [sqlite3_reset()], or after any call
4716** to [sqlite3_step()] regardless of whether or not the statement has
4717** completed execution.
4719** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4721** The application must finalize every [prepared statement] in order to avoid
4722** resource leaks. It is a grievous error for the application to try to use
4723** a prepared statement after it has been finalized. Any use of a prepared
4724** statement after it has been finalized can result in undefined and
4725** undesirable behavior such as segfaults and heap corruption.
4727SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
4730** CAPI3REF: Reset A Prepared Statement Object
4731** METHOD: sqlite3_stmt
4733** The sqlite3_reset() function is called to reset a [prepared statement]
4734** object back to its initial state, ready to be re-executed.
4735** ^Any SQL statement variables that had values bound to them using
4736** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4737** Use [sqlite3_clear_bindings()] to reset the bindings.
4739** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4740** back to the beginning of its program.
4742** ^If the most recent call to [sqlite3_step(S)] for the
4743** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4744** or if [sqlite3_step(S)] has never before been called on S,
4745** then [sqlite3_reset(S)] returns [SQLITE_OK].
4747** ^If the most recent call to [sqlite3_step(S)] for the
4748** [prepared statement] S indicated an error, then
4749** [sqlite3_reset(S)] returns an appropriate [error code].
4751** ^The [sqlite3_reset(S)] interface does not change the values
4752** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4754SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
4757** CAPI3REF: Create Or Redefine SQL Functions
4758** KEYWORDS: {function creation routines}
4759** KEYWORDS: {application-defined SQL function}
4760** KEYWORDS: {application-defined SQL functions}
4761** METHOD: sqlite3
4763** ^These functions (collectively known as "function creation routines")
4764** are used to add SQL functions or aggregates or to redefine the behavior
4765** of existing SQL functions or aggregates. The only differences between
4766** the three "sqlite3_create_function*" routines are the text encoding
4767** expected for the second parameter (the name of the function being
4768** created) and the presence or absence of a destructor callback for
4769** the application data pointer. Function sqlite3_create_window_function()
4770** is similar, but allows the user to supply the extra callback functions
4771** needed by [aggregate window functions].
4773** ^The first parameter is the [database connection] to which the SQL
4774** function is to be added. ^If an application uses more than one database
4775** connection then application-defined SQL functions must be added
4776** to each database connection separately.
4778** ^The second parameter is the name of the SQL function to be created or
4779** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
4780** representation, exclusive of the zero-terminator. ^Note that the name
4781** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4782** ^Any attempt to create a function with a longer name
4783** will result in [SQLITE_MISUSE] being returned.
4785** ^The third parameter (nArg)
4786** is the number of arguments that the SQL function or
4787** aggregate takes. ^If this parameter is -1, then the SQL function or
4788** aggregate may take any number of arguments between 0 and the limit
4789** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
4790** parameter is less than -1 or greater than 127 then the behavior is
4791** undefined.
4793** ^The fourth parameter, eTextRep, specifies what
4794** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4795** its parameters. The application should set this parameter to
4796** [SQLITE_UTF16LE] if the function implementation invokes
4797** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4798** implementation invokes [sqlite3_value_text16be()] on an input, or
4799** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4800** otherwise. ^The same SQL function may be registered multiple times using
4801** different preferred text encodings, with different implementations for
4802** each encoding.
4803** ^When multiple implementations of the same function are available, SQLite
4804** will pick the one that involves the least amount of data conversion.
4806** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4807** to signal that the function will always return the same result given
4808** the same inputs within a single SQL statement. Most SQL functions are
4809** deterministic. The built-in [random()] SQL function is an example of a
4810** function that is not deterministic. The SQLite query planner is able to
4811** perform additional optimizations on deterministic functions, so use
4812** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4814** ^(The fifth parameter is an arbitrary pointer. The implementation of the
4815** function can gain access to this pointer using [sqlite3_user_data()].)^
4817** ^The sixth, seventh and eighth parameters passed to the three
4818** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
4819** pointers to C-language functions that implement the SQL function or
4820** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4821** callback only; NULL pointers must be passed as the xStep and xFinal
4822** parameters. ^An aggregate SQL function requires an implementation of xStep
4823** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4824** SQL function or aggregate, pass NULL pointers for all three function
4825** callbacks.
4827** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
4828** and xInverse) passed to sqlite3_create_window_function are pointers to
4829** C-language callbacks that implement the new function. xStep and xFinal
4830** must both be non-NULL. xValue and xInverse may either both be NULL, in
4831** which case a regular aggregate function is created, or must both be
4832** non-NULL, in which case the new function may be used as either an aggregate
4833** or aggregate window function. More details regarding the implementation
4834** of aggregate window functions are
4835** [user-defined window functions|available here].
4837** ^(If the final parameter to sqlite3_create_function_v2() or
4838** sqlite3_create_window_function() is not NULL, then it is destructor for
4839** the application data pointer. The destructor is invoked when the function
4840** is deleted, either by being overloaded or when the database connection
4841** closes.)^ ^The destructor is also invoked if the call to
4842** sqlite3_create_function_v2() fails. ^When the destructor callback is
4843** invoked, it is passed a single argument which is a copy of the application
4844** data pointer which was the fifth parameter to sqlite3_create_function_v2().
4846** ^It is permitted to register multiple implementations of the same
4847** functions with the same name but with either differing numbers of
4848** arguments or differing preferred text encodings. ^SQLite will use
4849** the implementation that most closely matches the way in which the
4850** SQL function is used. ^A function implementation with a non-negative
4851** nArg parameter is a better match than a function implementation with
4852** a negative nArg. ^A function where the preferred text encoding
4853** matches the database encoding is a better
4854** match than a function where the encoding is different.
4855** ^A function where the encoding difference is between UTF16le and UTF16be
4856** is a closer match than a function where the encoding difference is
4857** between UTF8 and UTF16.
4859** ^Built-in functions may be overloaded by new application-defined functions.
4861** ^An application-defined function is permitted to call other
4862** SQLite interfaces. However, such calls must not
4863** close the database connection nor finalize or reset the prepared
4864** statement in which the function is running.
4866SQLITE_API int sqlite3_create_function(
4867 sqlite3 *db,
4868 const char *zFunctionName,
4869 int nArg,
4870 int eTextRep,
4871 void *pApp,
4872 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4873 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4874 void (*xFinal)(sqlite3_context*)
4876SQLITE_API int sqlite3_create_function16(
4877 sqlite3 *db,
4878 const void *zFunctionName,
4879 int nArg,
4880 int eTextRep,
4881 void *pApp,
4882 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4883 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4884 void (*xFinal)(sqlite3_context*)
4886SQLITE_API int sqlite3_create_function_v2(
4887 sqlite3 *db,
4888 const char *zFunctionName,
4889 int nArg,
4890 int eTextRep,
4891 void *pApp,
4892 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4893 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4894 void (*xFinal)(sqlite3_context*),
4895 void(*xDestroy)(void*)
4897SQLITE_API int sqlite3_create_window_function(
4898 sqlite3 *db,
4899 const char *zFunctionName,
4900 int nArg,
4901 int eTextRep,
4902 void *pApp,
4903 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4904 void (*xFinal)(sqlite3_context*),
4905 void (*xValue)(sqlite3_context*),
4906 void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
4907 void(*xDestroy)(void*)
4911** CAPI3REF: Text Encodings
4913** These constant define integer codes that represent the various
4914** text encodings supported by SQLite.
4916#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */
4917#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */
4918#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */
4919#define SQLITE_UTF16 4 /* Use native byte order */
4920#define SQLITE_ANY 5 /* Deprecated */
4921#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
4924** CAPI3REF: Function Flags
4926** These constants may be ORed together with the
4927** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4928** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4929** [sqlite3_create_function_v2()].
4931#define SQLITE_DETERMINISTIC 0x800
4934** CAPI3REF: Deprecated Functions
4937** These functions are [deprecated]. In order to maintain
4938** backwards compatibility with older code, these functions continue
4939** to be supported. However, new applications should avoid
4940** the use of these functions. To encourage programmers to avoid
4941** these functions, we will not explain what they do.
4944SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
4945SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
4946SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4947SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
4948SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
4949SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4950 void*,sqlite3_int64);
4954** CAPI3REF: Obtaining SQL Values
4955** METHOD: sqlite3_value
4957** <b>Summary:</b>
4958** <blockquote><table border=0 cellpadding=0 cellspacing=0>
4959** <tr><td><b>sqlite3_value_blob</b><td>&rarr;<td>BLOB value
4960** <tr><td><b>sqlite3_value_double</b><td>&rarr;<td>REAL value
4961** <tr><td><b>sqlite3_value_int</b><td>&rarr;<td>32-bit INTEGER value
4962** <tr><td><b>sqlite3_value_int64</b><td>&rarr;<td>64-bit INTEGER value
4963** <tr><td><b>sqlite3_value_pointer</b><td>&rarr;<td>Pointer value
4964** <tr><td><b>sqlite3_value_text</b><td>&rarr;<td>UTF-8 TEXT value
4965** <tr><td><b>sqlite3_value_text16</b><td>&rarr;<td>UTF-16 TEXT value in
4966** the native byteorder
4967** <tr><td><b>sqlite3_value_text16be</b><td>&rarr;<td>UTF-16be TEXT value
4968** <tr><td><b>sqlite3_value_text16le</b><td>&rarr;<td>UTF-16le TEXT value
4969** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
4970** <tr><td><b>sqlite3_value_bytes</b><td>&rarr;<td>Size of a BLOB
4971** or a UTF-8 TEXT in bytes
4972** <tr><td><b>sqlite3_value_bytes16&nbsp;&nbsp;</b>
4973** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
4974** TEXT in bytes
4975** <tr><td><b>sqlite3_value_type</b><td>&rarr;<td>Default
4976** datatype of the value
4977** <tr><td><b>sqlite3_value_numeric_type&nbsp;&nbsp;</b>
4978** <td>&rarr;&nbsp;&nbsp;<td>Best numeric datatype of the value
4979** <tr><td><b>sqlite3_value_nochange&nbsp;&nbsp;</b>
4980** <td>&rarr;&nbsp;&nbsp;<td>True if the column is unchanged in an UPDATE
4981** against a virtual table.
4982** <tr><td><b>sqlite3_value_frombind&nbsp;&nbsp;</b>
4983** <td>&rarr;&nbsp;&nbsp;<td>True if value originated from a [bound parameter]
4984** </table></blockquote>
4986** <b>Details:</b>
4988** These routines extract type, size, and content information from
4989** [protected sqlite3_value] objects. Protected sqlite3_value objects
4990** are used to pass parameter information into implementation of
4991** [application-defined SQL functions] and [virtual tables].
4993** These routines work only with [protected sqlite3_value] objects.
4994** Any attempt to use these routines on an [unprotected sqlite3_value]
4995** is not threadsafe.
4997** ^These routines work just like the corresponding [column access functions]
4998** except that these routines take a single [protected sqlite3_value] object
4999** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
5001** ^The sqlite3_value_text16() interface extracts a UTF-16 string
5002** in the native byte-order of the host machine. ^The
5003** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
5004** extract UTF-16 strings as big-endian and little-endian respectively.
5006** ^If [sqlite3_value] object V was initialized
5007** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
5008** and if X and Y are strings that compare equal according to strcmp(X,Y),
5009** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise,
5010** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
5011** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5013** ^(The sqlite3_value_type(V) interface returns the
5014** [SQLITE_INTEGER | datatype code] for the initial datatype of the
5015** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
5017** Other interfaces might change the datatype for an sqlite3_value object.
5018** For example, if the datatype is initially SQLITE_INTEGER and
5019** sqlite3_value_text(V) is called to extract a text value for that
5020** integer, then subsequent calls to sqlite3_value_type(V) might return
5021** SQLITE_TEXT. Whether or not a persistent internal datatype conversion
5022** occurs is undefined and may change from one release of SQLite to the next.
5024** ^(The sqlite3_value_numeric_type() interface attempts to apply
5025** numeric affinity to the value. This means that an attempt is
5026** made to convert the value to an integer or floating point. If
5027** such a conversion is possible without loss of information (in other
5028** words, if the value is a string that looks like a number)
5029** then the conversion is performed. Otherwise no conversion occurs.
5030** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
5032** ^Within the [xUpdate] method of a [virtual table], the
5033** sqlite3_value_nochange(X) interface returns true if and only if
5034** the column corresponding to X is unchanged by the UPDATE operation
5035** that the xUpdate method call was invoked to implement and if
5036** and the prior [xColumn] method call that was invoked to extracted
5037** the value for that column returned without setting a result (probably
5038** because it queried [sqlite3_vtab_nochange()] and found that the column
5039** was unchanging). ^Within an [xUpdate] method, any value for which
5040** sqlite3_value_nochange(X) is true will in all other respects appear
5041** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other
5042** than within an [xUpdate] method call for an UPDATE statement, then
5043** the return value is arbitrary and meaningless.
5045** ^The sqlite3_value_frombind(X) interface returns non-zero if the
5046** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()]
5047** interfaces. ^If X comes from an SQL literal value, or a table column,
5048** and expression, then sqlite3_value_frombind(X) returns zero.
5050** Please pay particular attention to the fact that the pointer returned
5051** from [sqlite3_value_blob()], [sqlite3_value_text()], or
5052** [sqlite3_value_text16()] can be invalidated by a subsequent call to
5053** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
5054** or [sqlite3_value_text16()].
5056** These routines must be called from the same thread as
5057** the SQL function that supplied the [sqlite3_value*] parameters.
5059** As long as the input parameter is correct, these routines can only
5060** fail if an out-of-memory error occurs during a format conversion.
5061** Only the following subset of interfaces are subject to out-of-memory
5062** errors:
5064** <ul>
5065** <li> sqlite3_value_blob()
5066** <li> sqlite3_value_text()
5067** <li> sqlite3_value_text16()
5068** <li> sqlite3_value_text16le()
5069** <li> sqlite3_value_text16be()
5070** <li> sqlite3_value_bytes()
5071** <li> sqlite3_value_bytes16()
5072** </ul>
5074** If an out-of-memory error occurs, then the return value from these
5075** routines is the same as if the column had contained an SQL NULL value.
5076** Valid SQL NULL returns can be distinguished from out-of-memory errors
5077** by invoking the [sqlite3_errcode()] immediately after the suspect
5078** return value is obtained and before any
5079** other SQLite interface is called on the same [database connection].
5081SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
5082SQLITE_API double sqlite3_value_double(sqlite3_value*);
5083SQLITE_API int sqlite3_value_int(sqlite3_value*);
5084SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
5085SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
5086SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
5087SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
5088SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
5089SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
5090SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
5091SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
5092SQLITE_API int sqlite3_value_type(sqlite3_value*);
5093SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
5094SQLITE_API int sqlite3_value_nochange(sqlite3_value*);
5095SQLITE_API int sqlite3_value_frombind(sqlite3_value*);
5098** CAPI3REF: Finding The Subtype Of SQL Values
5099** METHOD: sqlite3_value
5101** The sqlite3_value_subtype(V) function returns the subtype for
5102** an [application-defined SQL function] argument V. The subtype
5103** information can be used to pass a limited amount of context from
5104** one SQL function to another. Use the [sqlite3_result_subtype()]
5105** routine to set the subtype for the return value of an SQL function.
5107SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
5110** CAPI3REF: Copy And Free SQL Values
5111** METHOD: sqlite3_value
5113** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
5114** object D and returns a pointer to that copy. ^The [sqlite3_value] returned
5115** is a [protected sqlite3_value] object even if the input is not.
5116** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
5117** memory allocation fails.
5119** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
5120** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer
5121** then sqlite3_value_free(V) is a harmless no-op.
5123SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
5124SQLITE_API void sqlite3_value_free(sqlite3_value*);
5127** CAPI3REF: Obtain Aggregate Function Context
5128** METHOD: sqlite3_context
5130** Implementations of aggregate SQL functions use this
5131** routine to allocate memory for storing their state.
5133** ^The first time the sqlite3_aggregate_context(C,N) routine is called
5134** for a particular aggregate function, SQLite
5135** allocates N of memory, zeroes out that memory, and returns a pointer
5136** to the new memory. ^On second and subsequent calls to
5137** sqlite3_aggregate_context() for the same aggregate function instance,
5138** the same buffer is returned. Sqlite3_aggregate_context() is normally
5139** called once for each invocation of the xStep callback and then one
5140** last time when the xFinal callback is invoked. ^(When no rows match
5141** an aggregate query, the xStep() callback of the aggregate function
5142** implementation is never called and xFinal() is called exactly once.
5143** In those cases, sqlite3_aggregate_context() might be called for the
5144** first time from within xFinal().)^
5146** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
5147** when first called if N is less than or equal to zero or if a memory
5148** allocate error occurs.
5150** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
5151** determined by the N parameter on first successful call. Changing the
5152** value of N in subsequent call to sqlite3_aggregate_context() within
5153** the same aggregate function instance will not resize the memory
5154** allocation.)^ Within the xFinal callback, it is customary to set
5155** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
5156** pointless memory allocations occur.
5158** ^SQLite automatically frees the memory allocated by
5159** sqlite3_aggregate_context() when the aggregate query concludes.
5161** The first parameter must be a copy of the
5162** [sqlite3_context | SQL function context] that is the first parameter
5163** to the xStep or xFinal callback routine that implements the aggregate
5164** function.
5166** This routine must be called from the same thread in which
5167** the aggregate SQL function is running.
5169SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
5172** CAPI3REF: User Data For Functions
5173** METHOD: sqlite3_context
5175** ^The sqlite3_user_data() interface returns a copy of
5176** the pointer that was the pUserData parameter (the 5th parameter)
5177** of the [sqlite3_create_function()]
5178** and [sqlite3_create_function16()] routines that originally
5179** registered the application defined function.
5181** This routine must be called from the same thread in which
5182** the application-defined function is running.
5184SQLITE_API void *sqlite3_user_data(sqlite3_context*);
5187** CAPI3REF: Database Connection For Functions
5188** METHOD: sqlite3_context
5190** ^The sqlite3_context_db_handle() interface returns a copy of
5191** the pointer to the [database connection] (the 1st parameter)
5192** of the [sqlite3_create_function()]
5193** and [sqlite3_create_function16()] routines that originally
5194** registered the application defined function.
5196SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
5199** CAPI3REF: Function Auxiliary Data
5200** METHOD: sqlite3_context
5202** These functions may be used by (non-aggregate) SQL functions to
5203** associate metadata with argument values. If the same value is passed to
5204** multiple invocations of the same SQL function during query execution, under
5205** some circumstances the associated metadata may be preserved. An example
5206** of where this might be useful is in a regular-expression matching
5207** function. The compiled version of the regular expression can be stored as
5208** metadata associated with the pattern string.
5209** Then as long as the pattern string remains the same,
5210** the compiled regular expression can be reused on multiple
5211** invocations of the same function.
5213** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata
5214** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
5215** value to the application-defined function. ^N is zero for the left-most
5216** function argument. ^If there is no metadata
5217** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
5218** returns a NULL pointer.
5220** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
5221** argument of the application-defined function. ^Subsequent
5222** calls to sqlite3_get_auxdata(C,N) return P from the most recent
5223** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
5224** NULL if the metadata has been discarded.
5225** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
5226** SQLite will invoke the destructor function X with parameter P exactly
5227** once, when the metadata is discarded.
5228** SQLite is free to discard the metadata at any time, including: <ul>
5229** <li> ^(when the corresponding function parameter changes)^, or
5230** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
5231** SQL statement)^, or
5232** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
5233** parameter)^, or
5234** <li> ^(during the original sqlite3_set_auxdata() call when a memory
5235** allocation error occurs.)^ </ul>
5237** Note the last bullet in particular. The destructor X in
5238** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
5239** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
5240** should be called near the end of the function implementation and the
5241** function implementation should not make any use of P after
5242** sqlite3_set_auxdata() has been called.
5244** ^(In practice, metadata is preserved between function calls for
5245** function parameters that are compile-time constants, including literal
5246** values and [parameters] and expressions composed from the same.)^
5248** The value of the N parameter to these interfaces should be non-negative.
5249** Future enhancements may make use of negative N values to define new
5250** kinds of function caching behavior.
5252** These routines must be called from the same thread in which
5253** the SQL function is running.
5255SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
5256SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
5260** CAPI3REF: Constants Defining Special Destructor Behavior
5262** These are special values for the destructor that is passed in as the
5263** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
5264** argument is SQLITE_STATIC, it means that the content pointer is constant
5265** and will never change. It does not need to be destroyed. ^The
5266** SQLITE_TRANSIENT value means that the content will likely change in
5267** the near future and that SQLite should make its own private copy of
5268** the content before returning.
5270** The typedef is necessary to work around problems in certain
5271** C++ compilers.
5273typedef void (*sqlite3_destructor_type)(void*);
5274#define SQLITE_STATIC ((sqlite3_destructor_type)0)
5275#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
5278** CAPI3REF: Setting The Result Of An SQL Function
5279** METHOD: sqlite3_context
5281** These routines are used by the xFunc or xFinal callbacks that
5282** implement SQL functions and aggregates. See
5283** [sqlite3_create_function()] and [sqlite3_create_function16()]
5284** for additional information.
5286** These functions work very much like the [parameter binding] family of
5287** functions used to bind values to host parameters in prepared statements.
5288** Refer to the [SQL parameter] documentation for additional information.
5290** ^The sqlite3_result_blob() interface sets the result from
5291** an application-defined function to be the BLOB whose content is pointed
5292** to by the second parameter and which is N bytes long where N is the
5293** third parameter.
5295** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
5296** interfaces set the result of the application-defined function to be
5297** a BLOB containing all zero bytes and N bytes in size.
5299** ^The sqlite3_result_double() interface sets the result from
5300** an application-defined function to be a floating point value specified
5301** by its 2nd argument.
5303** ^The sqlite3_result_error() and sqlite3_result_error16() functions
5304** cause the implemented SQL function to throw an exception.
5305** ^SQLite uses the string pointed to by the
5306** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
5307** as the text of an error message. ^SQLite interprets the error
5308** message string from sqlite3_result_error() as UTF-8. ^SQLite
5309** interprets the string from sqlite3_result_error16() as UTF-16 in native
5310** byte order. ^If the third parameter to sqlite3_result_error()
5311** or sqlite3_result_error16() is negative then SQLite takes as the error
5312** message all text up through the first zero character.
5313** ^If the third parameter to sqlite3_result_error() or
5314** sqlite3_result_error16() is non-negative then SQLite takes that many
5315** bytes (not characters) from the 2nd parameter as the error message.
5316** ^The sqlite3_result_error() and sqlite3_result_error16()
5317** routines make a private copy of the error message text before
5318** they return. Hence, the calling function can deallocate or
5319** modify the text after they return without harm.
5320** ^The sqlite3_result_error_code() function changes the error code
5321** returned by SQLite as a result of an error in a function. ^By default,
5322** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
5323** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
5325** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
5326** error indicating that a string or BLOB is too long to represent.
5328** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
5329** error indicating that a memory allocation failed.
5331** ^The sqlite3_result_int() interface sets the return value
5332** of the application-defined function to be the 32-bit signed integer
5333** value given in the 2nd argument.
5334** ^The sqlite3_result_int64() interface sets the return value
5335** of the application-defined function to be the 64-bit signed integer
5336** value given in the 2nd argument.
5338** ^The sqlite3_result_null() interface sets the return value
5339** of the application-defined function to be NULL.
5341** ^The sqlite3_result_text(), sqlite3_result_text16(),
5342** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
5343** set the return value of the application-defined function to be
5344** a text string which is represented as UTF-8, UTF-16 native byte order,
5345** UTF-16 little endian, or UTF-16 big endian, respectively.
5346** ^The sqlite3_result_text64() interface sets the return value of an
5347** application-defined function to be a text string in an encoding
5348** specified by the fifth (and last) parameter, which must be one
5350** ^SQLite takes the text result from the application from
5351** the 2nd parameter of the sqlite3_result_text* interfaces.
5352** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5353** is negative, then SQLite takes result text from the 2nd parameter
5354** through the first zero character.
5355** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5356** is non-negative, then as many bytes (not characters) of the text
5357** pointed to by the 2nd parameter are taken as the application-defined
5358** function result. If the 3rd parameter is non-negative, then it
5359** must be the byte offset into the string where the NUL terminator would
5360** appear if the string where NUL terminated. If any NUL characters occur
5361** in the string at a byte offset that is less than the value of the 3rd
5362** parameter, then the resulting string will contain embedded NULs and the
5363** result of expressions operating on strings with embedded NULs is undefined.
5364** ^If the 4th parameter to the sqlite3_result_text* interfaces
5365** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
5366** function as the destructor on the text or BLOB result when it has
5367** finished using that result.
5368** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
5369** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
5370** assumes that the text or BLOB result is in constant space and does not
5371** copy the content of the parameter nor call a destructor on the content
5372** when it has finished using that result.
5373** ^If the 4th parameter to the sqlite3_result_text* interfaces
5374** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
5375** then SQLite makes a copy of the result into space obtained
5376** from [sqlite3_malloc()] before it returns.
5378** ^The sqlite3_result_value() interface sets the result of
5379** the application-defined function to be a copy of the
5380** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
5381** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
5382** so that the [sqlite3_value] specified in the parameter may change or
5383** be deallocated after sqlite3_result_value() returns without harm.
5384** ^A [protected sqlite3_value] object may always be used where an
5385** [unprotected sqlite3_value] object is required, so either
5386** kind of [sqlite3_value] object can be used with this interface.
5388** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
5389** SQL NULL value, just like [sqlite3_result_null(C)], except that it
5390** also associates the host-language pointer P or type T with that
5391** NULL value such that the pointer can be retrieved within an
5392** [application-defined SQL function] using [sqlite3_value_pointer()].
5393** ^If the D parameter is not NULL, then it is a pointer to a destructor
5394** for the P parameter. ^SQLite invokes D with P as its only argument
5395** when SQLite is finished with P. The T parameter should be a static
5396** string and preferably a string literal. The sqlite3_result_pointer()
5397** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5399** If these routines are called from within the different thread
5400** than the one containing the application-defined function that received
5401** the [sqlite3_context] pointer, the results are undefined.
5403SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
5404SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
5405 sqlite3_uint64,void(*)(void*));
5406SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
5407SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
5408SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
5409SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
5410SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
5411SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
5412SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
5413SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
5414SQLITE_API void sqlite3_result_null(sqlite3_context*);
5415SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
5416SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
5417 void(*)(void*), unsigned char encoding);
5418SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
5419SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
5420SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
5421SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
5422SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
5423SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
5424SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
5428** CAPI3REF: Setting The Subtype Of An SQL Function
5429** METHOD: sqlite3_context
5431** The sqlite3_result_subtype(C,T) function causes the subtype of
5432** the result from the [application-defined SQL function] with
5433** [sqlite3_context] C to be the value T. Only the lower 8 bits
5434** of the subtype T are preserved in current versions of SQLite;
5435** higher order bits are discarded.
5436** The number of subtype bytes preserved by SQLite might increase
5437** in future releases of SQLite.
5439SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
5442** CAPI3REF: Define New Collating Sequences
5443** METHOD: sqlite3
5445** ^These functions add, remove, or modify a [collation] associated
5446** with the [database connection] specified as the first argument.
5448** ^The name of the collation is a UTF-8 string
5449** for sqlite3_create_collation() and sqlite3_create_collation_v2()
5450** and a UTF-16 string in native byte order for sqlite3_create_collation16().
5451** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
5452** considered to be the same name.
5454** ^(The third argument (eTextRep) must be one of the constants:
5455** <ul>
5456** <li> [SQLITE_UTF8],
5457** <li> [SQLITE_UTF16LE],
5458** <li> [SQLITE_UTF16BE],
5459** <li> [SQLITE_UTF16], or
5460** <li> [SQLITE_UTF16_ALIGNED].
5461** </ul>)^
5462** ^The eTextRep argument determines the encoding of strings passed
5463** to the collating function callback, xCallback.
5464** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
5465** force strings to be UTF16 with native byte order.
5466** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
5467** on an even byte address.
5469** ^The fourth argument, pArg, is an application data pointer that is passed
5470** through as the first argument to the collating function callback.
5472** ^The fifth argument, xCallback, is a pointer to the collating function.
5473** ^Multiple collating functions can be registered using the same name but
5474** with different eTextRep parameters and SQLite will use whichever
5475** function requires the least amount of data transformation.
5476** ^If the xCallback argument is NULL then the collating function is
5477** deleted. ^When all collating functions having the same name are deleted,
5478** that collation is no longer usable.
5480** ^The collating function callback is invoked with a copy of the pArg
5481** application data pointer and with two strings in the encoding specified
5482** by the eTextRep argument. The collating function must return an
5483** integer that is negative, zero, or positive
5484** if the first string is less than, equal to, or greater than the second,
5485** respectively. A collating function must always return the same answer
5486** given the same inputs. If two or more collating functions are registered
5487** to the same collation name (using different eTextRep values) then all
5488** must give an equivalent answer when invoked with equivalent strings.
5489** The collating function must obey the following properties for all
5490** strings A, B, and C:
5492** <ol>
5493** <li> If A==B then B==A.
5494** <li> If A==B and B==C then A==C.
5495** <li> If A&lt;B THEN B&gt;A.
5496** <li> If A&lt;B and B&lt;C then A&lt;C.
5497** </ol>
5499** If a collating function fails any of the above constraints and that
5500** collating function is registered and used, then the behavior of SQLite
5501** is undefined.
5503** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
5504** with the addition that the xDestroy callback is invoked on pArg when
5505** the collating function is deleted.
5506** ^Collating functions are deleted when they are overridden by later
5507** calls to the collation creation functions or when the
5508** [database connection] is closed using [sqlite3_close()].
5510** ^The xDestroy callback is <u>not</u> called if the
5511** sqlite3_create_collation_v2() function fails. Applications that invoke
5512** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
5513** check the return code and dispose of the application data pointer
5514** themselves rather than expecting SQLite to deal with it for them.
5515** This is different from every other SQLite interface. The inconsistency
5516** is unfortunate but cannot be changed without breaking backwards
5517** compatibility.
5519** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
5521SQLITE_API int sqlite3_create_collation(
5522 sqlite3*,
5523 const char *zName,
5524 int eTextRep,
5525 void *pArg,
5526 int(*xCompare)(void*,int,const void*,int,const void*)
5528SQLITE_API int sqlite3_create_collation_v2(
5529 sqlite3*,
5530 const char *zName,
5531 int eTextRep,
5532 void *pArg,
5533 int(*xCompare)(void*,int,const void*,int,const void*),
5534 void(*xDestroy)(void*)
5536SQLITE_API int sqlite3_create_collation16(
5537 sqlite3*,
5538 const void *zName,
5539 int eTextRep,
5540 void *pArg,
5541 int(*xCompare)(void*,int,const void*,int,const void*)
5545** CAPI3REF: Collation Needed Callbacks
5546** METHOD: sqlite3
5548** ^To avoid having to register all collation sequences before a database
5549** can be used, a single callback function may be registered with the
5550** [database connection] to be invoked whenever an undefined collation
5551** sequence is required.
5553** ^If the function is registered using the sqlite3_collation_needed() API,
5554** then it is passed the names of undefined collation sequences as strings
5555** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
5556** the names are passed as UTF-16 in machine native byte order.
5557** ^A call to either function replaces the existing collation-needed callback.
5559** ^(When the callback is invoked, the first argument passed is a copy
5560** of the second argument to sqlite3_collation_needed() or
5561** sqlite3_collation_needed16(). The second argument is the database
5562** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
5563** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
5564** sequence function required. The fourth parameter is the name of the
5565** required collation sequence.)^
5567** The callback function should register the desired collation using
5568** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
5569** [sqlite3_create_collation_v2()].
5571SQLITE_API int sqlite3_collation_needed(
5572 sqlite3*,
5573 void*,
5574 void(*)(void*,sqlite3*,int eTextRep,const char*)
5576SQLITE_API int sqlite3_collation_needed16(
5577 sqlite3*,
5578 void*,
5579 void(*)(void*,sqlite3*,int eTextRep,const void*)
5584** Specify the key for an encrypted database. This routine should be
5585** called right after sqlite3_open().
5587** The code to implement this API is not available in the public release
5588** of SQLite.
5590SQLITE_API int sqlite3_key(
5591 sqlite3 *db, /* Database to be rekeyed */
5592 const void *pKey, int nKey /* The key */
5594SQLITE_API int sqlite3_key_v2(
5595 sqlite3 *db, /* Database to be rekeyed */
5596 const char *zDbName, /* Name of the database */
5597 const void *pKey, int nKey /* The key */
5601** Change the key on an open database. If the current database is not
5602** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
5603** database is decrypted.
5605** The code to implement this API is not available in the public release
5606** of SQLite.
5608SQLITE_API int sqlite3_rekey(
5609 sqlite3 *db, /* Database to be rekeyed */
5610 const void *pKey, int nKey /* The new key */
5612SQLITE_API int sqlite3_rekey_v2(
5613 sqlite3 *db, /* Database to be rekeyed */
5614 const char *zDbName, /* Name of the database */
5615 const void *pKey, int nKey /* The new key */
5619** Specify the activation key for a SEE database. Unless
5620** activated, none of the SEE routines will work.
5622SQLITE_API void sqlite3_activate_see(
5623 const char *zPassPhrase /* Activation phrase */
5629** Specify the activation key for a CEROD database. Unless
5630** activated, none of the CEROD routines will work.
5632SQLITE_API void sqlite3_activate_cerod(
5633 const char *zPassPhrase /* Activation phrase */
5638** CAPI3REF: Suspend Execution For A Short Time
5640** The sqlite3_sleep() function causes the current thread to suspend execution
5641** for at least a number of milliseconds specified in its parameter.
5643** If the operating system does not support sleep requests with
5644** millisecond time resolution, then the time will be rounded up to
5645** the nearest second. The number of milliseconds of sleep actually
5646** requested from the operating system is returned.
5648** ^SQLite implements this interface by calling the xSleep()
5649** method of the default [sqlite3_vfs] object. If the xSleep() method
5650** of the default VFS is not implemented correctly, or not implemented at
5651** all, then the behavior of sqlite3_sleep() may deviate from the description
5652** in the previous paragraphs.
5654SQLITE_API int sqlite3_sleep(int);
5657** CAPI3REF: Name Of The Folder Holding Temporary Files
5659** ^(If this global variable is made to point to a string which is
5660** the name of a folder (a.k.a. directory), then all temporary files
5661** created by SQLite when using a built-in [sqlite3_vfs | VFS]
5662** will be placed in that directory.)^ ^If this variable
5663** is a NULL pointer, then SQLite performs a search for an appropriate
5664** temporary file directory.
5666** Applications are strongly discouraged from using this global variable.
5667** It is required to set a temporary folder on Windows Runtime (WinRT).
5668** But for all other platforms, it is highly recommended that applications
5669** neither read nor write this variable. This global variable is a relic
5670** that exists for backwards compatibility of legacy applications and should
5671** be avoided in new projects.
5673** It is not safe to read or modify this variable in more than one
5674** thread at a time. It is not safe to read or modify this variable
5675** if a [database connection] is being used at the same time in a separate
5676** thread.
5677** It is intended that this variable be set once
5678** as part of process initialization and before any SQLite interface
5679** routines have been called and that this variable remain unchanged
5680** thereafter.
5682** ^The [temp_store_directory pragma] may modify this variable and cause
5683** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
5684** the [temp_store_directory pragma] always assumes that any string
5685** that this variable points to is held in memory obtained from
5686** [sqlite3_malloc] and the pragma may attempt to free that memory
5687** using [sqlite3_free].
5688** Hence, if this variable is modified directly, either it should be
5689** made NULL or made to point to memory obtained from [sqlite3_malloc]
5690** or else the use of the [temp_store_directory pragma] should be avoided.
5691** Except when requested by the [temp_store_directory pragma], SQLite
5692** does not free the memory that sqlite3_temp_directory points to. If
5693** the application wants that memory to be freed, it must do
5694** so itself, taking care to only do so after all [database connection]
5695** objects have been destroyed.
5697** <b>Note to Windows Runtime users:</b> The temporary directory must be set
5698** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
5699** features that require the use of temporary files may fail. Here is an
5700** example of how to do this using C++ with the Windows Runtime:
5702** <blockquote><pre>
5703** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
5704** &nbsp; TemporaryFolder->Path->Data();
5705** char zPathBuf&#91;MAX_PATH + 1&#93;;
5706** memset(zPathBuf, 0, sizeof(zPathBuf));
5707** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
5708** &nbsp; NULL, NULL);
5709** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
5710** </pre></blockquote>
5712SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
5715** CAPI3REF: Name Of The Folder Holding Database Files
5717** ^(If this global variable is made to point to a string which is
5718** the name of a folder (a.k.a. directory), then all database files
5719** specified with a relative pathname and created or accessed by
5720** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
5721** to be relative to that directory.)^ ^If this variable is a NULL
5722** pointer, then SQLite assumes that all database files specified
5723** with a relative pathname are relative to the current directory
5724** for the process. Only the windows VFS makes use of this global
5725** variable; it is ignored by the unix VFS.
5727** Changing the value of this variable while a database connection is
5728** open can result in a corrupt database.
5730** It is not safe to read or modify this variable in more than one
5731** thread at a time. It is not safe to read or modify this variable
5732** if a [database connection] is being used at the same time in a separate
5733** thread.
5734** It is intended that this variable be set once
5735** as part of process initialization and before any SQLite interface
5736** routines have been called and that this variable remain unchanged
5737** thereafter.
5739** ^The [data_store_directory pragma] may modify this variable and cause
5740** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
5741** the [data_store_directory pragma] always assumes that any string
5742** that this variable points to is held in memory obtained from
5743** [sqlite3_malloc] and the pragma may attempt to free that memory
5744** using [sqlite3_free].
5745** Hence, if this variable is modified directly, either it should be
5746** made NULL or made to point to memory obtained from [sqlite3_malloc]
5747** or else the use of the [data_store_directory pragma] should be avoided.
5749SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
5752** CAPI3REF: Win32 Specific Interface
5754** These interfaces are available only on Windows. The
5755** [sqlite3_win32_set_directory] interface is used to set the value associated
5756** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
5757** zValue, depending on the value of the type parameter. The zValue parameter
5758** should be NULL to cause the previous value to be freed via [sqlite3_free];
5759** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
5760** prior to being used. The [sqlite3_win32_set_directory] interface returns
5761** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
5762** or [SQLITE_NOMEM] if memory could not be allocated. The value of the
5763** [sqlite3_data_directory] variable is intended to act as a replacement for
5764** the current directory on the sub-platforms of Win32 where that concept is
5765** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and
5766** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
5767** sqlite3_win32_set_directory interface except the string parameter must be
5768** UTF-8 or UTF-16, respectively.
5770SQLITE_API int sqlite3_win32_set_directory(
5771 unsigned long type, /* Identifier for directory being set or reset */
5772 void *zValue /* New value for directory being set or reset */
5774SQLITE_API int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
5775SQLITE_API int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
5778** CAPI3REF: Win32 Directory Types
5780** These macros are only available on Windows. They define the allowed values
5781** for the type argument to the [sqlite3_win32_set_directory] interface.
5787** CAPI3REF: Test For Auto-Commit Mode
5788** KEYWORDS: {autocommit mode}
5789** METHOD: sqlite3
5791** ^The sqlite3_get_autocommit() interface returns non-zero or
5792** zero if the given database connection is or is not in autocommit mode,
5793** respectively. ^Autocommit mode is on by default.
5794** ^Autocommit mode is disabled by a [BEGIN] statement.
5795** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
5797** If certain kinds of errors occur on a statement within a multi-statement
5798** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
5800** transaction might be rolled back automatically. The only way to
5801** find out whether SQLite automatically rolled back the transaction after
5802** an error is to use this function.
5804** If another thread changes the autocommit status of the database
5805** connection while this routine is running, then the return value
5806** is undefined.
5808SQLITE_API int sqlite3_get_autocommit(sqlite3*);
5811** CAPI3REF: Find The Database Handle Of A Prepared Statement
5812** METHOD: sqlite3_stmt
5814** ^The sqlite3_db_handle interface returns the [database connection] handle
5815** to which a [prepared statement] belongs. ^The [database connection]
5816** returned by sqlite3_db_handle is the same [database connection]
5817** that was the first argument
5818** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
5819** create the statement in the first place.
5821SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
5824** CAPI3REF: Return The Filename For A Database Connection
5825** METHOD: sqlite3
5827** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
5828** associated with database N of connection D. ^The main database file
5829** has the name "main". If there is no attached database N on the database
5830** connection D, or if database N is a temporary or in-memory database, then
5831** this function will return either a NULL pointer or an empty string.
5833** ^The filename returned by this function is the output of the
5834** xFullPathname method of the [VFS]. ^In other words, the filename
5835** will be an absolute pathname, even if the filename used
5836** to open the database originally was a URI or relative pathname.
5838SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
5841** CAPI3REF: Determine if a database is read-only
5842** METHOD: sqlite3
5844** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
5845** of connection D is read-only, 0 if it is read/write, or -1 if N is not
5846** the name of a database on connection D.
5848SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
5851** CAPI3REF: Find the next prepared statement
5852** METHOD: sqlite3
5854** ^This interface returns a pointer to the next [prepared statement] after
5855** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
5856** then this interface returns a pointer to the first prepared statement
5857** associated with the database connection pDb. ^If no prepared statement
5858** satisfies the conditions of this routine, it returns NULL.
5860** The [database connection] pointer D in a call to
5861** [sqlite3_next_stmt(D,S)] must refer to an open database
5862** connection and in particular must not be a NULL pointer.
5864SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
5867** CAPI3REF: Commit And Rollback Notification Callbacks
5868** METHOD: sqlite3
5870** ^The sqlite3_commit_hook() interface registers a callback
5871** function to be invoked whenever a transaction is [COMMIT | committed].
5872** ^Any callback set by a previous call to sqlite3_commit_hook()
5873** for the same database connection is overridden.
5874** ^The sqlite3_rollback_hook() interface registers a callback
5875** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
5876** ^Any callback set by a previous call to sqlite3_rollback_hook()
5877** for the same database connection is overridden.
5878** ^The pArg argument is passed through to the callback.
5879** ^If the callback on a commit hook function returns non-zero,
5880** then the commit is converted into a rollback.
5882** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
5883** return the P argument from the previous call of the same function
5884** on the same [database connection] D, or NULL for
5885** the first call for each function on D.
5887** The commit and rollback hook callbacks are not reentrant.
5888** The callback implementation must not do anything that will modify
5889** the database connection that invoked the callback. Any actions
5890** to modify the database connection must be deferred until after the
5891** completion of the [sqlite3_step()] call that triggered the commit
5892** or rollback hook in the first place.
5893** Note that running any other SQL statements, including SELECT statements,
5894** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
5895** the database connections for the meaning of "modify" in this paragraph.
5897** ^Registering a NULL function disables the callback.
5899** ^When the commit hook callback routine returns zero, the [COMMIT]
5900** operation is allowed to continue normally. ^If the commit hook
5901** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
5902** ^The rollback hook is invoked on a rollback that results from a commit
5903** hook returning non-zero, just as it would be with any other rollback.
5905** ^For the purposes of this API, a transaction is said to have been
5906** rolled back if an explicit "ROLLBACK" statement is executed, or
5907** an error or constraint causes an implicit rollback to occur.
5908** ^The rollback callback is not invoked if a transaction is
5909** automatically rolled back because the database connection is closed.
5911** See also the [sqlite3_update_hook()] interface.
5913SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
5914SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
5917** CAPI3REF: Data Change Notification Callbacks
5918** METHOD: sqlite3
5920** ^The sqlite3_update_hook() interface registers a callback function
5921** with the [database connection] identified by the first argument
5922** to be invoked whenever a row is updated, inserted or deleted in
5923** a [rowid table].
5924** ^Any callback set by a previous call to this function
5925** for the same database connection is overridden.
5927** ^The second argument is a pointer to the function to invoke when a
5928** row is updated, inserted or deleted in a rowid table.
5929** ^The first argument to the callback is a copy of the third argument
5930** to sqlite3_update_hook().
5931** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
5932** or [SQLITE_UPDATE], depending on the operation that caused the callback
5933** to be invoked.
5934** ^The third and fourth arguments to the callback contain pointers to the
5935** database and table name containing the affected row.
5936** ^The final callback parameter is the [rowid] of the row.
5937** ^In the case of an update, this is the [rowid] after the update takes place.
5939** ^(The update hook is not invoked when internal system tables are
5940** modified (i.e. sqlite_master and sqlite_sequence).)^
5941** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
5943** ^In the current implementation, the update hook
5944** is not invoked when conflicting rows are deleted because of an
5945** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
5946** invoked when rows are deleted using the [truncate optimization].
5947** The exceptions defined in this paragraph might change in a future
5948** release of SQLite.
5950** The update hook implementation must not do anything that will modify
5951** the database connection that invoked the update hook. Any actions
5952** to modify the database connection must be deferred until after the
5953** completion of the [sqlite3_step()] call that triggered the update hook.
5954** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
5955** database connections for the meaning of "modify" in this paragraph.
5957** ^The sqlite3_update_hook(D,C,P) function
5958** returns the P argument from the previous call
5959** on the same [database connection] D, or NULL for
5960** the first call on D.
5962** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
5963** and [sqlite3_preupdate_hook()] interfaces.
5965SQLITE_API void *sqlite3_update_hook(
5966 sqlite3*,
5967 void(*)(void *,int ,char const *,char const *,sqlite3_int64),
5968 void*
5972** CAPI3REF: Enable Or Disable Shared Pager Cache
5974** ^(This routine enables or disables the sharing of the database cache
5975** and schema data structures between [database connection | connections]
5976** to the same database. Sharing is enabled if the argument is true
5977** and disabled if the argument is false.)^
5979** ^Cache sharing is enabled and disabled for an entire process.
5980** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
5981** In prior versions of SQLite,
5982** sharing was enabled or disabled for each thread separately.
5984** ^(The cache sharing mode set by this interface effects all subsequent
5985** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
5986** Existing database connections continue use the sharing mode
5987** that was in effect at the time they were opened.)^
5989** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
5990** successfully. An [error code] is returned otherwise.)^
5992** ^Shared cache is disabled by default. But this might change in
5993** future releases of SQLite. Applications that care about shared
5994** cache setting should set it explicitly.
5996** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
5997** and will always return SQLITE_MISUSE. On those systems,
5998** shared cache mode should be enabled per-database connection via
5999** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
6001** This interface is threadsafe on processors where writing a
6002** 32-bit integer is atomic.
6004** See Also: [SQLite Shared-Cache Mode]
6006SQLITE_API int sqlite3_enable_shared_cache(int);
6009** CAPI3REF: Attempt To Free Heap Memory
6011** ^The sqlite3_release_memory() interface attempts to free N bytes
6012** of heap memory by deallocating non-essential memory allocations
6013** held by the database library. Memory used to cache database
6014** pages to improve performance is an example of non-essential memory.
6015** ^sqlite3_release_memory() returns the number of bytes actually freed,
6016** which might be more or less than the amount requested.
6017** ^The sqlite3_release_memory() routine is a no-op returning zero
6018** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
6020** See also: [sqlite3_db_release_memory()]
6022SQLITE_API int sqlite3_release_memory(int);
6025** CAPI3REF: Free Memory Used By A Database Connection
6026** METHOD: sqlite3
6028** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
6029** memory as possible from database connection D. Unlike the
6030** [sqlite3_release_memory()] interface, this interface is in effect even
6031** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
6032** omitted.
6034** See also: [sqlite3_release_memory()]
6036SQLITE_API int sqlite3_db_release_memory(sqlite3*);
6039** CAPI3REF: Impose A Limit On Heap Size
6041** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
6042** soft limit on the amount of heap memory that may be allocated by SQLite.
6043** ^SQLite strives to keep heap memory utilization below the soft heap
6044** limit by reducing the number of pages held in the page cache
6045** as heap memory usages approaches the limit.
6046** ^The soft heap limit is "soft" because even though SQLite strives to stay
6047** below the limit, it will exceed the limit rather than generate
6048** an [SQLITE_NOMEM] error. In other words, the soft heap limit
6049** is advisory only.
6051** ^The return value from sqlite3_soft_heap_limit64() is the size of
6052** the soft heap limit prior to the call, or negative in the case of an
6053** error. ^If the argument N is negative
6054** then no change is made to the soft heap limit. Hence, the current
6055** size of the soft heap limit can be determined by invoking
6056** sqlite3_soft_heap_limit64() with a negative argument.
6058** ^If the argument N is zero then the soft heap limit is disabled.
6060** ^(The soft heap limit is not enforced in the current implementation
6061** if one or more of following conditions are true:
6063** <ul>
6064** <li> The soft heap limit is set to zero.
6065** <li> Memory accounting is disabled using a combination of the
6066** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
6067** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
6068** <li> An alternative page cache implementation is specified using
6069** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
6070** <li> The page cache allocates from its own memory pool supplied
6071** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
6072** from the heap.
6073** </ul>)^
6075** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]),
6076** the soft heap limit is enforced
6077** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
6078** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
6079** the soft heap limit is enforced on every memory allocation. Without
6080** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
6081** when memory is allocated by the page cache. Testing suggests that because
6082** the page cache is the predominate memory user in SQLite, most
6083** applications will achieve adequate soft heap limit enforcement without
6086** The circumstances under which SQLite will enforce the soft heap limit may
6087** changes in future releases of SQLite.
6089SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
6092** CAPI3REF: Deprecated Soft Heap Limit Interface
6095** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
6096** interface. This routine is provided for historical compatibility
6097** only. All new applications should use the
6098** [sqlite3_soft_heap_limit64()] interface rather than this one.
6100SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
6104** CAPI3REF: Extract Metadata About A Column Of A Table
6105** METHOD: sqlite3
6107** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
6108** information about column C of table T in database D
6109** on [database connection] X.)^ ^The sqlite3_table_column_metadata()
6110** interface returns SQLITE_OK and fills in the non-NULL pointers in
6111** the final five arguments with appropriate values if the specified
6112** column exists. ^The sqlite3_table_column_metadata() interface returns
6113** SQLITE_ERROR and if the specified column does not exist.
6114** ^If the column-name parameter to sqlite3_table_column_metadata() is a
6115** NULL pointer, then this routine simply checks for the existence of the
6116** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
6117** does not. If the table name parameter T in a call to
6118** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
6119** undefined behavior.
6121** ^The column is identified by the second, third and fourth parameters to
6122** this function. ^(The second parameter is either the name of the database
6123** (i.e. "main", "temp", or an attached database) containing the specified
6124** table or NULL.)^ ^If it is NULL, then all attached databases are searched
6125** for the table using the same algorithm used by the database engine to
6126** resolve unqualified table references.
6128** ^The third and fourth parameters to this function are the table and column
6129** name of the desired column, respectively.
6131** ^Metadata is returned by writing to the memory locations passed as the 5th
6132** and subsequent parameters to this function. ^Any of these arguments may be
6133** NULL, in which case the corresponding element of metadata is omitted.
6135** ^(<blockquote>
6136** <table border="1">
6137** <tr><th> Parameter <th> Output<br>Type <th> Description
6139** <tr><td> 5th <td> const char* <td> Data type
6140** <tr><td> 6th <td> const char* <td> Name of default collation sequence
6141** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
6142** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
6143** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
6144** </table>
6145** </blockquote>)^
6147** ^The memory pointed to by the character pointers returned for the
6148** declaration type and collation sequence is valid until the next
6149** call to any SQLite API function.
6151** ^If the specified table is actually a view, an [error code] is returned.
6153** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
6154** is not a [WITHOUT ROWID] table and an
6155** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
6156** parameters are set for the explicitly declared column. ^(If there is no
6157** [INTEGER PRIMARY KEY] column, then the outputs
6158** for the [rowid] are set as follows:
6160** <pre>
6161** data type: "INTEGER"
6162** collation sequence: "BINARY"
6163** not null: 0
6164** primary key: 1
6165** auto increment: 0
6166** </pre>)^
6168** ^This function causes all database schemas to be read from disk and
6169** parsed, if that has not already been done, and returns an error if
6170** any errors are encountered while loading the schema.
6172SQLITE_API int sqlite3_table_column_metadata(
6173 sqlite3 *db, /* Connection handle */
6174 const char *zDbName, /* Database name or NULL */
6175 const char *zTableName, /* Table name */
6176 const char *zColumnName, /* Column name */
6177 char const **pzDataType, /* OUTPUT: Declared data type */
6178 char const **pzCollSeq, /* OUTPUT: Collation sequence name */
6179 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
6180 int *pPrimaryKey, /* OUTPUT: True if column part of PK */
6181 int *pAutoinc /* OUTPUT: True if column is auto-increment */
6185** CAPI3REF: Load An Extension
6186** METHOD: sqlite3
6188** ^This interface loads an SQLite extension library from the named file.
6190** ^The sqlite3_load_extension() interface attempts to load an
6191** [SQLite extension] library contained in the file zFile. If
6192** the file cannot be loaded directly, attempts are made to load
6193** with various operating-system specific extensions added.
6194** So for example, if "samplelib" cannot be loaded, then names like
6195** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
6196** be tried also.
6198** ^The entry point is zProc.
6199** ^(zProc may be 0, in which case SQLite will try to come up with an
6200** entry point name on its own. It first tries "sqlite3_extension_init".
6201** If that does not work, it constructs a name "sqlite3_X_init" where the
6202** X is consists of the lower-case equivalent of all ASCII alphabetic
6203** characters in the filename from the last "/" to the first following
6204** "." and omitting any initial "lib".)^
6205** ^The sqlite3_load_extension() interface returns
6206** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
6207** ^If an error occurs and pzErrMsg is not 0, then the
6208** [sqlite3_load_extension()] interface shall attempt to
6209** fill *pzErrMsg with error message text stored in memory
6210** obtained from [sqlite3_malloc()]. The calling function
6211** should free this memory by calling [sqlite3_free()].
6213** ^Extension loading must be enabled using
6214** [sqlite3_enable_load_extension()] or
6215** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
6216** prior to calling this API,
6217** otherwise an error will be returned.
6219** <b>Security warning:</b> It is recommended that the
6220** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
6221** interface. The use of the [sqlite3_enable_load_extension()] interface
6222** should be avoided. This will keep the SQL function [load_extension()]
6223** disabled and prevent SQL injections from giving attackers
6224** access to extension loading capabilities.
6226** See also the [load_extension() SQL function].
6228SQLITE_API int sqlite3_load_extension(
6229 sqlite3 *db, /* Load the extension into this database connection */
6230 const char *zFile, /* Name of the shared library containing extension */
6231 const char *zProc, /* Entry point. Derived from zFile if 0 */
6232 char **pzErrMsg /* Put error message here if not 0 */
6236** CAPI3REF: Enable Or Disable Extension Loading
6237** METHOD: sqlite3
6239** ^So as not to open security holes in older applications that are
6240** unprepared to deal with [extension loading], and as a means of disabling
6241** [extension loading] while evaluating user-entered SQL, the following API
6242** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
6244** ^Extension loading is off by default.
6245** ^Call the sqlite3_enable_load_extension() routine with onoff==1
6246** to turn extension loading on and call it with onoff==0 to turn
6247** it back off again.
6249** ^This interface enables or disables both the C-API
6250** [sqlite3_load_extension()] and the SQL function [load_extension()].
6251** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
6252** to enable or disable only the C-API.)^
6254** <b>Security warning:</b> It is recommended that extension loading
6255** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
6256** rather than this interface, so the [load_extension()] SQL function
6257** remains disabled. This will prevent SQL injections from giving attackers
6258** access to extension loading capabilities.
6260SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
6263** CAPI3REF: Automatically Load Statically Linked Extensions
6265** ^This interface causes the xEntryPoint() function to be invoked for
6266** each new [database connection] that is created. The idea here is that
6267** xEntryPoint() is the entry point for a statically linked [SQLite extension]
6268** that is to be automatically loaded into all new database connections.
6270** ^(Even though the function prototype shows that xEntryPoint() takes
6271** no arguments and returns void, SQLite invokes xEntryPoint() with three
6272** arguments and expects an integer result as if the signature of the
6273** entry point where as follows:
6275** <blockquote><pre>
6276** &nbsp; int xEntryPoint(
6277** &nbsp; sqlite3 *db,
6278** &nbsp; const char **pzErrMsg,
6279** &nbsp; const struct sqlite3_api_routines *pThunk
6280** &nbsp; );
6281** </pre></blockquote>)^
6283** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
6284** point to an appropriate error message (obtained from [sqlite3_mprintf()])
6285** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
6286** is NULL before calling the xEntryPoint(). ^SQLite will invoke
6287** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
6288** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
6289** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
6291** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
6292** on the list of automatic extensions is a harmless no-op. ^No entry point
6293** will be called more than once for each database connection that is opened.
6295** See also: [sqlite3_reset_auto_extension()]
6296** and [sqlite3_cancel_auto_extension()]
6298SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
6301** CAPI3REF: Cancel Automatic Extension Loading
6303** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
6304** initialization routine X that was registered using a prior call to
6305** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)]
6306** routine returns 1 if initialization routine X was successfully
6307** unregistered and it returns 0 if X was not on the list of initialization
6308** routines.
6310SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
6313** CAPI3REF: Reset Automatic Extension Loading
6315** ^This interface disables all automatic extensions previously
6316** registered using [sqlite3_auto_extension()].
6318SQLITE_API void sqlite3_reset_auto_extension(void);
6321** The interface to the virtual-table mechanism is currently considered
6322** to be experimental. The interface might change in incompatible ways.
6323** If this is a problem for you, do not use the interface at this time.
6325** When the virtual-table mechanism stabilizes, we will declare the
6326** interface fixed, support it indefinitely, and remove this comment.
6330** Structures used by the virtual table interface
6332typedef struct sqlite3_vtab sqlite3_vtab;
6333typedef struct sqlite3_index_info sqlite3_index_info;
6334typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
6335typedef struct sqlite3_module sqlite3_module;
6338** CAPI3REF: Virtual Table Object
6339** KEYWORDS: sqlite3_module {virtual table module}
6341** This structure, sometimes called a "virtual table module",
6342** defines the implementation of a [virtual tables].
6343** This structure consists mostly of methods for the module.
6345** ^A virtual table module is created by filling in a persistent
6346** instance of this structure and passing a pointer to that instance
6347** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
6348** ^The registration remains valid until it is replaced by a different
6349** module or until the [database connection] closes. The content
6350** of this structure must not change while it is registered with
6351** any database connection.
6353struct sqlite3_module {
6354 int iVersion;
6355 int (*xCreate)(sqlite3*, void *pAux,
6356 int argc, const char *const*argv,
6357 sqlite3_vtab **ppVTab, char**);
6358 int (*xConnect)(sqlite3*, void *pAux,
6359 int argc, const char *const*argv,
6360 sqlite3_vtab **ppVTab, char**);
6361 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
6362 int (*xDisconnect)(sqlite3_vtab *pVTab);
6363 int (*xDestroy)(sqlite3_vtab *pVTab);
6364 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
6365 int (*xClose)(sqlite3_vtab_cursor*);
6366 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
6367 int argc, sqlite3_value **argv);
6368 int (*xNext)(sqlite3_vtab_cursor*);
6369 int (*xEof)(sqlite3_vtab_cursor*);
6370 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
6371 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
6372 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
6373 int (*xBegin)(sqlite3_vtab *pVTab);
6374 int (*xSync)(sqlite3_vtab *pVTab);
6375 int (*xCommit)(sqlite3_vtab *pVTab);
6376 int (*xRollback)(sqlite3_vtab *pVTab);
6377 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
6378 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
6379 void **ppArg);
6380 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
6381 /* The methods above are in version 1 of the sqlite_module object. Those
6382 ** below are for version 2 and greater. */
6383 int (*xSavepoint)(sqlite3_vtab *pVTab, int);
6384 int (*xRelease)(sqlite3_vtab *pVTab, int);
6385 int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
6386 /* The methods above are in versions 1 and 2 of the sqlite_module object.
6387 ** Those below are for version 3 and greater. */
6388 int (*xShadowName)(const char*);
6392** CAPI3REF: Virtual Table Indexing Information
6393** KEYWORDS: sqlite3_index_info
6395** The sqlite3_index_info structure and its substructures is used as part
6396** of the [virtual table] interface to
6397** pass information into and receive the reply from the [xBestIndex]
6398** method of a [virtual table module]. The fields under **Inputs** are the
6399** inputs to xBestIndex and are read-only. xBestIndex inserts its
6400** results into the **Outputs** fields.
6402** ^(The aConstraint[] array records WHERE clause constraints of the form:
6404** <blockquote>column OP expr</blockquote>
6406** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^ ^(The particular operator is
6407** stored in aConstraint[].op using one of the
6409** ^(The index of the column is stored in
6410** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
6411** expr on the right-hand side can be evaluated (and thus the constraint
6412** is usable) and false if it cannot.)^
6414** ^The optimizer automatically inverts terms of the form "expr OP column"
6415** and makes other simplifications to the WHERE clause in an attempt to
6416** get as many WHERE clause terms into the form shown above as possible.
6417** ^The aConstraint[] array only reports WHERE clause terms that are
6418** relevant to the particular virtual table being queried.
6420** ^Information about the ORDER BY clause is stored in aOrderBy[].
6421** ^Each term of aOrderBy records a column of the ORDER BY clause.
6423** The colUsed field indicates which columns of the virtual table may be
6424** required by the current scan. Virtual table columns are numbered from
6425** zero in the order in which they appear within the CREATE TABLE statement
6426** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
6427** the corresponding bit is set within the colUsed mask if the column may be
6428** required by SQLite. If the table has at least 64 columns and any column
6429** to the right of the first 63 is required, then bit 63 of colUsed is also
6430** set. In other words, column iCol may be required if the expression
6431** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
6432** non-zero.
6434** The [xBestIndex] method must fill aConstraintUsage[] with information
6435** about what parameters to pass to xFilter. ^If argvIndex>0 then
6436** the right-hand side of the corresponding aConstraint[] is evaluated
6437** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
6438** is true, then the constraint is assumed to be fully handled by the
6439** virtual table and is not checked again by SQLite.)^
6441** ^The idxNum and idxPtr values are recorded and passed into the
6442** [xFilter] method.
6443** ^[sqlite3_free()] is used to free idxPtr if and only if
6444** needToFreeIdxPtr is true.
6446** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
6447** the correct order to satisfy the ORDER BY clause so that no separate
6448** sorting step is required.
6450** ^The estimatedCost value is an estimate of the cost of a particular
6451** strategy. A cost of N indicates that the cost of the strategy is similar
6452** to a linear scan of an SQLite table with N rows. A cost of log(N)
6453** indicates that the expense of the operation is similar to that of a
6454** binary search on a unique indexed field of an SQLite table with N rows.
6456** ^The estimatedRows value is an estimate of the number of rows that
6457** will be returned by the strategy.
6459** The xBestIndex method may optionally populate the idxFlags field with a
6460** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
6461** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
6462** assumes that the strategy may visit at most one row.
6464** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
6465** SQLite also assumes that if a call to the xUpdate() method is made as
6466** part of the same statement to delete or update a virtual table row and the
6467** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
6468** any database changes. In other words, if the xUpdate() returns
6469** SQLITE_CONSTRAINT, the database contents must be exactly as they were
6470** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
6471** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
6472** the xUpdate method are automatically rolled back by SQLite.
6474** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
6475** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
6476** If a virtual table extension is
6477** used with an SQLite version earlier than 3.8.2, the results of attempting
6478** to read or write the estimatedRows field are undefined (but are likely
6479** to included crashing the application). The estimatedRows field should
6480** therefore only be used if [sqlite3_libversion_number()] returns a
6481** value greater than or equal to 3008002. Similarly, the idxFlags field
6482** was added for [version 3.9.0] ([dateof:3.9.0]).
6483** It may therefore only be used if
6484** sqlite3_libversion_number() returns a value greater than or equal to
6485** 3009000.
6487struct sqlite3_index_info {
6488 /* Inputs */
6489 int nConstraint; /* Number of entries in aConstraint */
6490 struct sqlite3_index_constraint {
6491 int iColumn; /* Column constrained. -1 for ROWID */
6492 unsigned char op; /* Constraint operator */
6493 unsigned char usable; /* True if this constraint is usable */
6494 int iTermOffset; /* Used internally - xBestIndex should ignore */
6495 } *aConstraint; /* Table of WHERE clause constraints */
6496 int nOrderBy; /* Number of terms in the ORDER BY clause */
6497 struct sqlite3_index_orderby {
6498 int iColumn; /* Column number */
6499 unsigned char desc; /* True for DESC. False for ASC. */
6500 } *aOrderBy; /* The ORDER BY clause */
6501 /* Outputs */
6502 struct sqlite3_index_constraint_usage {
6503 int argvIndex; /* if >0, constraint is part of argv to xFilter */
6504 unsigned char omit; /* Do not code a test for this constraint */
6505 } *aConstraintUsage;
6506 int idxNum; /* Number used to identify the index */
6507 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
6508 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
6509 int orderByConsumed; /* True if output is already ordered */
6510 double estimatedCost; /* Estimated cost of using this index */
6511 /* Fields below are only available in SQLite 3.8.2 and later */
6512 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */
6513 /* Fields below are only available in SQLite 3.9.0 and later */
6514 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */
6515 /* Fields below are only available in SQLite 3.10.0 and later */
6516 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */
6520** CAPI3REF: Virtual Table Scan Flags
6522** Virtual table implementations are allowed to set the
6523** [sqlite3_index_info].idxFlags field to some combination of
6524** these bits.
6526#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */
6529** CAPI3REF: Virtual Table Constraint Operator Codes
6531** These macros defined the allowed values for the
6532** [sqlite3_index_info].aConstraint[].op field. Each value represents
6533** an operator that is part of a constraint term in the wHERE clause of
6534** a query that uses a [virtual table].
6553** CAPI3REF: Register A Virtual Table Implementation
6554** METHOD: sqlite3
6556** ^These routines are used to register a new [virtual table module] name.
6557** ^Module names must be registered before
6558** creating a new [virtual table] using the module and before using a
6559** preexisting [virtual table] for the module.
6561** ^The module name is registered on the [database connection] specified
6562** by the first parameter. ^The name of the module is given by the
6563** second parameter. ^The third parameter is a pointer to
6564** the implementation of the [virtual table module]. ^The fourth
6565** parameter is an arbitrary client data pointer that is passed through
6566** into the [xCreate] and [xConnect] methods of the virtual table module
6567** when a new virtual table is be being created or reinitialized.
6569** ^The sqlite3_create_module_v2() interface has a fifth parameter which
6570** is a pointer to a destructor for the pClientData. ^SQLite will
6571** invoke the destructor function (if it is not NULL) when SQLite
6572** no longer needs the pClientData pointer. ^The destructor will also
6573** be invoked if the call to sqlite3_create_module_v2() fails.
6574** ^The sqlite3_create_module()
6575** interface is equivalent to sqlite3_create_module_v2() with a NULL
6576** destructor.
6578SQLITE_API int sqlite3_create_module(
6579 sqlite3 *db, /* SQLite connection to register module with */
6580 const char *zName, /* Name of the module */
6581 const sqlite3_module *p, /* Methods for the module */
6582 void *pClientData /* Client data for xCreate/xConnect */
6584SQLITE_API int sqlite3_create_module_v2(
6585 sqlite3 *db, /* SQLite connection to register module with */
6586 const char *zName, /* Name of the module */
6587 const sqlite3_module *p, /* Methods for the module */
6588 void *pClientData, /* Client data for xCreate/xConnect */
6589 void(*xDestroy)(void*) /* Module destructor function */
6593** CAPI3REF: Virtual Table Instance Object
6594** KEYWORDS: sqlite3_vtab
6596** Every [virtual table module] implementation uses a subclass
6597** of this object to describe a particular instance
6598** of the [virtual table]. Each subclass will
6599** be tailored to the specific needs of the module implementation.
6600** The purpose of this superclass is to define certain fields that are
6601** common to all module implementations.
6603** ^Virtual tables methods can set an error message by assigning a
6604** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
6605** take care that any prior string is freed by a call to [sqlite3_free()]
6606** prior to assigning a new string to zErrMsg. ^After the error message
6607** is delivered up to the client application, the string will be automatically
6608** freed by sqlite3_free() and the zErrMsg field will be zeroed.
6610struct sqlite3_vtab {
6611 const sqlite3_module *pModule; /* The module for this virtual table */
6612 int nRef; /* Number of open cursors */
6613 char *zErrMsg; /* Error message from sqlite3_mprintf() */
6614 /* Virtual table implementations will typically add additional fields */
6618** CAPI3REF: Virtual Table Cursor Object
6619** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
6621** Every [virtual table module] implementation uses a subclass of the
6622** following structure to describe cursors that point into the
6623** [virtual table] and are used
6624** to loop through the virtual table. Cursors are created using the
6625** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
6626** by the [sqlite3_module.xClose | xClose] method. Cursors are used
6627** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
6628** of the module. Each module implementation will define
6629** the content of a cursor structure to suit its own needs.
6631** This superclass exists in order to define fields of the cursor that
6632** are common to all implementations.
6634struct sqlite3_vtab_cursor {
6635 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
6636 /* Virtual table implementations will typically add additional fields */
6640** CAPI3REF: Declare The Schema Of A Virtual Table
6642** ^The [xCreate] and [xConnect] methods of a
6643** [virtual table module] call this interface
6644** to declare the format (the names and datatypes of the columns) of
6645** the virtual tables they implement.
6647SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
6650** CAPI3REF: Overload A Function For A Virtual Table
6651** METHOD: sqlite3
6653** ^(Virtual tables can provide alternative implementations of functions
6654** using the [xFindFunction] method of the [virtual table module].
6655** But global versions of those functions
6656** must exist in order to be overloaded.)^
6658** ^(This API makes sure a global version of a function with a particular
6659** name and number of parameters exists. If no such function exists
6660** before this API is called, a new function is created.)^ ^The implementation
6661** of the new function always causes an exception to be thrown. So
6662** the new function is not good for anything by itself. Its only
6663** purpose is to be a placeholder function that can be overloaded
6664** by a [virtual table].
6666SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
6669** The interface to the virtual-table mechanism defined above (back up
6670** to a comment remarkably similar to this one) is currently considered
6671** to be experimental. The interface might change in incompatible ways.
6672** If this is a problem for you, do not use the interface at this time.
6674** When the virtual-table mechanism stabilizes, we will declare the
6675** interface fixed, support it indefinitely, and remove this comment.
6679** CAPI3REF: A Handle To An Open BLOB
6680** KEYWORDS: {BLOB handle} {BLOB handles}
6682** An instance of this object represents an open BLOB on which
6683** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
6684** ^Objects of this type are created by [sqlite3_blob_open()]
6685** and destroyed by [sqlite3_blob_close()].
6686** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
6687** can be used to read or write small subsections of the BLOB.
6688** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
6690typedef struct sqlite3_blob sqlite3_blob;
6693** CAPI3REF: Open A BLOB For Incremental I/O
6694** METHOD: sqlite3
6695** CONSTRUCTOR: sqlite3_blob
6697** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
6698** in row iRow, column zColumn, table zTable in database zDb;
6699** in other words, the same BLOB that would be selected by:
6701** <pre>
6702** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
6703** </pre>)^
6705** ^(Parameter zDb is not the filename that contains the database, but
6706** rather the symbolic name of the database. For attached databases, this is
6707** the name that appears after the AS keyword in the [ATTACH] statement.
6708** For the main database file, the database name is "main". For TEMP
6709** tables, the database name is "temp".)^
6711** ^If the flags parameter is non-zero, then the BLOB is opened for read
6712** and write access. ^If the flags parameter is zero, the BLOB is opened for
6713** read-only access.
6715** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
6716** in *ppBlob. Otherwise an [error code] is returned and, unless the error
6717** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
6718** the API is not misused, it is always safe to call [sqlite3_blob_close()]
6719** on *ppBlob after this function it returns.
6721** This function fails with SQLITE_ERROR if any of the following are true:
6722** <ul>
6723** <li> ^(Database zDb does not exist)^,
6724** <li> ^(Table zTable does not exist within database zDb)^,
6725** <li> ^(Table zTable is a WITHOUT ROWID table)^,
6726** <li> ^(Column zColumn does not exist)^,
6727** <li> ^(Row iRow is not present in the table)^,
6728** <li> ^(The specified column of row iRow contains a value that is not
6729** a TEXT or BLOB value)^,
6730** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
6731** constraint and the blob is being opened for read/write access)^,
6732** <li> ^([foreign key constraints | Foreign key constraints] are enabled,
6733** column zColumn is part of a [child key] definition and the blob is
6734** being opened for read/write access)^.
6735** </ul>
6737** ^Unless it returns SQLITE_MISUSE, this function sets the
6738** [database connection] error code and message accessible via
6739** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6741** A BLOB referenced by sqlite3_blob_open() may be read using the
6742** [sqlite3_blob_read()] interface and modified by using
6743** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a
6744** different row of the same table using the [sqlite3_blob_reopen()]
6745** interface. However, the column, table, or database of a [BLOB handle]
6746** cannot be changed after the [BLOB handle] is opened.
6748** ^(If the row that a BLOB handle points to is modified by an
6749** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
6750** then the BLOB handle is marked as "expired".
6751** This is true if any column of the row is changed, even a column
6752** other than the one the BLOB handle is open on.)^
6753** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
6754** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
6755** ^(Changes written into a BLOB prior to the BLOB expiring are not
6756** rolled back by the expiration of the BLOB. Such changes will eventually
6757** commit if the transaction continues to completion.)^
6759** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
6760** the opened blob. ^The size of a blob may not be changed by this
6761** interface. Use the [UPDATE] SQL command to change the size of a
6762** blob.
6764** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
6765** and the built-in [zeroblob] SQL function may be used to create a
6766** zero-filled blob to read or write using the incremental-blob interface.
6768** To avoid a resource leak, every open [BLOB handle] should eventually
6769** be released by a call to [sqlite3_blob_close()].
6771** See also: [sqlite3_blob_close()],
6772** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
6773** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
6775SQLITE_API int sqlite3_blob_open(
6776 sqlite3*,
6777 const char *zDb,
6778 const char *zTable,
6779 const char *zColumn,
6780 sqlite3_int64 iRow,
6781 int flags,
6782 sqlite3_blob **ppBlob
6786** CAPI3REF: Move a BLOB Handle to a New Row
6787** METHOD: sqlite3_blob
6789** ^This function is used to move an existing [BLOB handle] so that it points
6790** to a different row of the same database table. ^The new row is identified
6791** by the rowid value passed as the second argument. Only the row can be
6792** changed. ^The database, table and column on which the blob handle is open
6793** remain the same. Moving an existing [BLOB handle] to a new row is
6794** faster than closing the existing handle and opening a new one.
6796** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
6797** it must exist and there must be either a blob or text value stored in
6798** the nominated column.)^ ^If the new row is not present in the table, or if
6799** it does not contain a blob or text value, or if another error occurs, an
6800** SQLite error code is returned and the blob handle is considered aborted.
6801** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
6802** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
6803** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
6804** always returns zero.
6806** ^This function sets the database handle error code and message.
6808SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
6811** CAPI3REF: Close A BLOB Handle
6812** DESTRUCTOR: sqlite3_blob
6814** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
6815** unconditionally. Even if this routine returns an error code, the
6816** handle is still closed.)^
6818** ^If the blob handle being closed was opened for read-write access, and if
6819** the database is in auto-commit mode and there are no other open read-write
6820** blob handles or active write statements, the current transaction is
6821** committed. ^If an error occurs while committing the transaction, an error
6822** code is returned and the transaction rolled back.
6824** Calling this function with an argument that is not a NULL pointer or an
6825** open blob handle results in undefined behaviour. ^Calling this routine
6826** with a null pointer (such as would be returned by a failed call to
6827** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
6828** is passed a valid open blob handle, the values returned by the
6829** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
6831SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
6834** CAPI3REF: Return The Size Of An Open BLOB
6835** METHOD: sqlite3_blob
6837** ^Returns the size in bytes of the BLOB accessible via the
6838** successfully opened [BLOB handle] in its only argument. ^The
6839** incremental blob I/O routines can only read or overwriting existing
6840** blob content; they cannot change the size of a blob.
6842** This routine only works on a [BLOB handle] which has been created
6843** by a prior successful call to [sqlite3_blob_open()] and which has not
6844** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6845** to this routine results in undefined and probably undesirable behavior.
6847SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
6850** CAPI3REF: Read Data From A BLOB Incrementally
6851** METHOD: sqlite3_blob
6853** ^(This function is used to read data from an open [BLOB handle] into a
6854** caller-supplied buffer. N bytes of data are copied into buffer Z
6855** from the open BLOB, starting at offset iOffset.)^
6857** ^If offset iOffset is less than N bytes from the end of the BLOB,
6858** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
6859** less than zero, [SQLITE_ERROR] is returned and no data is read.
6860** ^The size of the blob (and hence the maximum value of N+iOffset)
6861** can be determined using the [sqlite3_blob_bytes()] interface.
6863** ^An attempt to read from an expired [BLOB handle] fails with an
6864** error code of [SQLITE_ABORT].
6866** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
6867** Otherwise, an [error code] or an [extended error code] is returned.)^
6869** This routine only works on a [BLOB handle] which has been created
6870** by a prior successful call to [sqlite3_blob_open()] and which has not
6871** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6872** to this routine results in undefined and probably undesirable behavior.
6874** See also: [sqlite3_blob_write()].
6876SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
6879** CAPI3REF: Write Data Into A BLOB Incrementally
6880** METHOD: sqlite3_blob
6882** ^(This function is used to write data into an open [BLOB handle] from a
6883** caller-supplied buffer. N bytes of data are copied from the buffer Z
6884** into the open BLOB, starting at offset iOffset.)^
6886** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
6887** Otherwise, an [error code] or an [extended error code] is returned.)^
6888** ^Unless SQLITE_MISUSE is returned, this function sets the
6889** [database connection] error code and message accessible via
6890** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6892** ^If the [BLOB handle] passed as the first argument was not opened for
6893** writing (the flags parameter to [sqlite3_blob_open()] was zero),
6894** this function returns [SQLITE_READONLY].
6896** This function may only modify the contents of the BLOB; it is
6897** not possible to increase the size of a BLOB using this API.
6898** ^If offset iOffset is less than N bytes from the end of the BLOB,
6899** [SQLITE_ERROR] is returned and no data is written. The size of the
6900** BLOB (and hence the maximum value of N+iOffset) can be determined
6901** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
6902** than zero [SQLITE_ERROR] is returned and no data is written.
6904** ^An attempt to write to an expired [BLOB handle] fails with an
6905** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
6906** before the [BLOB handle] expired are not rolled back by the
6907** expiration of the handle, though of course those changes might
6908** have been overwritten by the statement that expired the BLOB handle
6909** or by other independent statements.
6911** This routine only works on a [BLOB handle] which has been created
6912** by a prior successful call to [sqlite3_blob_open()] and which has not
6913** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6914** to this routine results in undefined and probably undesirable behavior.
6916** See also: [sqlite3_blob_read()].
6918SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
6921** CAPI3REF: Virtual File System Objects
6923** A virtual filesystem (VFS) is an [sqlite3_vfs] object
6924** that SQLite uses to interact
6925** with the underlying operating system. Most SQLite builds come with a
6926** single default VFS that is appropriate for the host computer.
6927** New VFSes can be registered and existing VFSes can be unregistered.
6928** The following interfaces are provided.
6930** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
6931** ^Names are case sensitive.
6932** ^Names are zero-terminated UTF-8 strings.
6933** ^If there is no match, a NULL pointer is returned.
6934** ^If zVfsName is NULL then the default VFS is returned.
6936** ^New VFSes are registered with sqlite3_vfs_register().
6937** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
6938** ^The same VFS can be registered multiple times without injury.
6939** ^To make an existing VFS into the default VFS, register it again
6940** with the makeDflt flag set. If two different VFSes with the
6941** same name are registered, the behavior is undefined. If a
6942** VFS is registered with a name that is NULL or an empty string,
6943** then the behavior is undefined.
6945** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
6946** ^(If the default VFS is unregistered, another VFS is chosen as
6947** the default. The choice for the new VFS is arbitrary.)^
6949SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
6950SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
6951SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
6954** CAPI3REF: Mutexes
6956** The SQLite core uses these routines for thread
6957** synchronization. Though they are intended for internal
6958** use by SQLite, code that links against SQLite is
6959** permitted to use any of these routines.
6961** The SQLite source code contains multiple implementations
6962** of these mutex routines. An appropriate implementation
6963** is selected automatically at compile-time. The following
6964** implementations are available in the SQLite core:
6966** <ul>
6968** <li> SQLITE_MUTEX_W32
6970** </ul>
6972** The SQLITE_MUTEX_NOOP implementation is a set of routines
6973** that does no real locking and is appropriate for use in
6974** a single-threaded application. The SQLITE_MUTEX_PTHREADS and
6975** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
6976** and Windows.
6978** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
6979** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
6980** implementation is included with the library. In this case the
6981** application must supply a custom mutex implementation using the
6982** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
6983** before calling sqlite3_initialize() or any other public sqlite3_
6984** function that calls sqlite3_initialize().
6986** ^The sqlite3_mutex_alloc() routine allocates a new
6987** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
6988** routine returns NULL if it is unable to allocate the requested
6989** mutex. The argument to sqlite3_mutex_alloc() must one of these
6990** integer constants:
6992** <ul>
7007** </ul>
7009** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
7010** cause sqlite3_mutex_alloc() to create
7011** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
7012** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
7013** The mutex implementation does not need to make a distinction
7014** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
7015** not want to. SQLite will only request a recursive mutex in
7016** cases where it really needs one. If a faster non-recursive mutex
7017** implementation is available on the host platform, the mutex subsystem
7018** might return such a mutex in response to SQLITE_MUTEX_FAST.
7020** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
7022** a pointer to a static preexisting mutex. ^Nine static mutexes are
7023** used by the current version of SQLite. Future versions of SQLite
7024** may add additional static mutexes. Static mutexes are for internal
7025** use by SQLite only. Applications that use SQLite mutexes should
7026** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
7029** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
7030** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
7031** returns a different mutex on every call. ^For the static
7032** mutex types, the same mutex is returned on every call that has
7033** the same type number.
7035** ^The sqlite3_mutex_free() routine deallocates a previously
7036** allocated dynamic mutex. Attempting to deallocate a static
7037** mutex results in undefined behavior.
7039** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
7040** to enter a mutex. ^If another thread is already within the mutex,
7041** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
7042** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
7043** upon successful entry. ^(Mutexes created using
7044** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
7045** In such cases, the
7046** mutex must be exited an equal number of times before another thread
7047** can enter.)^ If the same thread tries to enter any mutex other
7048** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
7050** ^(Some systems (for example, Windows 95) do not support the operation
7051** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
7052** will always return SQLITE_BUSY. The SQLite core only ever uses
7053** sqlite3_mutex_try() as an optimization so this is acceptable
7054** behavior.)^
7056** ^The sqlite3_mutex_leave() routine exits a mutex that was
7057** previously entered by the same thread. The behavior
7058** is undefined if the mutex is not currently entered by the
7059** calling thread or is not currently allocated.
7061** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
7062** sqlite3_mutex_leave() is a NULL pointer, then all three routines
7063** behave as no-ops.
7065** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
7067SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
7068SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
7069SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
7070SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
7071SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
7074** CAPI3REF: Mutex Methods Object
7076** An instance of this structure defines the low-level routines
7077** used to allocate and use mutexes.
7079** Usually, the default mutex implementations provided by SQLite are
7080** sufficient, however the application has the option of substituting a custom
7081** implementation for specialized deployments or systems for which SQLite
7082** does not provide a suitable implementation. In this case, the application
7083** creates and populates an instance of this structure to pass
7084** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
7085** Additionally, an instance of this structure can be used as an
7086** output variable when querying the system for the current mutex
7087** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
7089** ^The xMutexInit method defined by this structure is invoked as
7090** part of system initialization by the sqlite3_initialize() function.
7091** ^The xMutexInit routine is called by SQLite exactly once for each
7092** effective call to [sqlite3_initialize()].
7094** ^The xMutexEnd method defined by this structure is invoked as
7095** part of system shutdown by the sqlite3_shutdown() function. The
7096** implementation of this method is expected to release all outstanding
7097** resources obtained by the mutex methods implementation, especially
7098** those obtained by the xMutexInit method. ^The xMutexEnd()
7099** interface is invoked exactly once for each call to [sqlite3_shutdown()].
7101** ^(The remaining seven methods defined by this structure (xMutexAlloc,
7102** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
7103** xMutexNotheld) implement the following interfaces (respectively):
7105** <ul>
7106** <li> [sqlite3_mutex_alloc()] </li>
7107** <li> [sqlite3_mutex_free()] </li>
7108** <li> [sqlite3_mutex_enter()] </li>
7109** <li> [sqlite3_mutex_try()] </li>
7110** <li> [sqlite3_mutex_leave()] </li>
7111** <li> [sqlite3_mutex_held()] </li>
7112** <li> [sqlite3_mutex_notheld()] </li>
7113** </ul>)^
7115** The only difference is that the public sqlite3_XXX functions enumerated
7116** above silently ignore any invocations that pass a NULL pointer instead
7117** of a valid mutex handle. The implementations of the methods defined
7118** by this structure are not required to handle this case, the results
7119** of passing a NULL pointer instead of a valid mutex handle are undefined
7120** (i.e. it is acceptable to provide an implementation that segfaults if
7121** it is passed a NULL pointer).
7123** The xMutexInit() method must be threadsafe. It must be harmless to
7124** invoke xMutexInit() multiple times within the same process and without
7125** intervening calls to xMutexEnd(). Second and subsequent calls to
7126** xMutexInit() must be no-ops.
7128** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
7129** and its associates). Similarly, xMutexAlloc() must not use SQLite memory
7130** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
7131** memory allocation for a fast or recursive mutex.
7133** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
7134** called, but only if the prior call to xMutexInit returned SQLITE_OK.
7135** If xMutexInit fails in any way, it is expected to clean up after itself
7136** prior to returning.
7138typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
7139struct sqlite3_mutex_methods {
7140 int (*xMutexInit)(void);
7141 int (*xMutexEnd)(void);
7142 sqlite3_mutex *(*xMutexAlloc)(int);
7143 void (*xMutexFree)(sqlite3_mutex *);
7144 void (*xMutexEnter)(sqlite3_mutex *);
7145 int (*xMutexTry)(sqlite3_mutex *);
7146 void (*xMutexLeave)(sqlite3_mutex *);
7147 int (*xMutexHeld)(sqlite3_mutex *);
7148 int (*xMutexNotheld)(sqlite3_mutex *);
7152** CAPI3REF: Mutex Verification Routines
7154** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
7155** are intended for use inside assert() statements. The SQLite core
7156** never uses these routines except inside an assert() and applications
7157** are advised to follow the lead of the core. The SQLite core only
7158** provides implementations for these routines when it is compiled
7159** with the SQLITE_DEBUG flag. External mutex implementations
7160** are only required to provide these routines if SQLITE_DEBUG is
7161** defined and if NDEBUG is not defined.
7163** These routines should return true if the mutex in their argument
7164** is held or not held, respectively, by the calling thread.
7166** The implementation is not required to provide versions of these
7167** routines that actually work. If the implementation does not provide working
7168** versions of these routines, it should at least provide stubs that always
7169** return true so that one does not get spurious assertion failures.
7171** If the argument to sqlite3_mutex_held() is a NULL pointer then
7172** the routine should return 1. This seems counter-intuitive since
7173** clearly the mutex cannot be held if it does not exist. But
7174** the reason the mutex does not exist is because the build is not
7175** using mutexes. And we do not want the assert() containing the
7176** call to sqlite3_mutex_held() to fail, so a non-zero return is
7177** the appropriate thing to do. The sqlite3_mutex_notheld()
7178** interface should also return 1 when given a NULL pointer.
7180#ifndef NDEBUG
7181SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
7182SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
7186** CAPI3REF: Mutex Types
7188** The [sqlite3_mutex_alloc()] interface takes a single argument
7189** which is one of these integer constants.
7191** The set of static mutexes may change from one SQLite release to the
7192** next. Applications that override the built-in mutex logic must be
7193** prepared to accommodate additional static mutexes.
7195#define SQLITE_MUTEX_FAST 0
7198#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
7200#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
7201#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */
7202#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
7204#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
7205#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */
7206#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */
7207#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */
7208#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */
7209#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */
7210#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */
7213** CAPI3REF: Retrieve the mutex for a database connection
7214** METHOD: sqlite3
7216** ^This interface returns a pointer the [sqlite3_mutex] object that
7217** serializes access to the [database connection] given in the argument
7218** when the [threading mode] is Serialized.
7219** ^If the [threading mode] is Single-thread or Multi-thread then this
7220** routine returns a NULL pointer.
7222SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
7225** CAPI3REF: Low-Level Control Of Database Files
7226** METHOD: sqlite3
7227** KEYWORDS: {file control}
7229** ^The [sqlite3_file_control()] interface makes a direct call to the
7230** xFileControl method for the [sqlite3_io_methods] object associated
7231** with a particular database identified by the second argument. ^The
7232** name of the database is "main" for the main database or "temp" for the
7233** TEMP database, or the name that appears after the AS keyword for
7234** databases that are added using the [ATTACH] SQL command.
7235** ^A NULL pointer can be used in place of "main" to refer to the
7236** main database file.
7237** ^The third and fourth parameters to this routine
7238** are passed directly through to the second and third parameters of
7239** the xFileControl method. ^The return value of the xFileControl
7240** method becomes the return value of this routine.
7242** A few opcodes for [sqlite3_file_control()] are handled directly
7243** by the SQLite core and never invoke the
7244** sqlite3_io_methods.xFileControl method.
7245** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
7246** a pointer to the underlying [sqlite3_file] object to be written into
7247** the space pointed to by the 4th parameter. The
7248** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns
7249** the [sqlite3_file] object associated with the journal file instead of
7250** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns
7251** a pointer to the underlying [sqlite3_vfs] object for the file.
7252** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter
7253** from the pager.
7255** ^If the second parameter (zDbName) does not match the name of any
7256** open database file, then SQLITE_ERROR is returned. ^This error
7257** code is not remembered and will not be recalled by [sqlite3_errcode()]
7258** or [sqlite3_errmsg()]. The underlying xFileControl method might
7259** also return SQLITE_ERROR. There is no way to distinguish between
7260** an incorrect zDbName and an SQLITE_ERROR return from the underlying
7261** xFileControl method.
7263** See also: [file control opcodes]
7265SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
7268** CAPI3REF: Testing Interface
7270** ^The sqlite3_test_control() interface is used to read out internal
7271** state of SQLite and to inject faults into SQLite for testing
7272** purposes. ^The first parameter is an operation code that determines
7273** the number, meaning, and operation of all subsequent parameters.
7275** This interface is not for use by applications. It exists solely
7276** for verifying the correct operation of the SQLite library. Depending
7277** on how the SQLite library is compiled, this interface might not exist.
7279** The details of the operation codes, their meanings, the parameters
7280** they take, and what they do are all subject to change without notice.
7281** Unlike most of the SQLite API, this function is not guaranteed to
7282** operate consistently from one release to the next.
7284SQLITE_API int sqlite3_test_control(int op, ...);
7287** CAPI3REF: Testing Interface Operation Codes
7289** These constants are the valid operation code parameters used
7290** as the first argument to [sqlite3_test_control()].
7292** These parameters and their meanings are subject to change
7293** without notice. These values are for testing purposes only.
7294** Applications should not use any of these parameters or the
7295** [sqlite3_test_control()] interface.
7322#define SQLITE_TESTCTRL_LAST 26 /* Largest TESTCTRL */
7325** CAPI3REF: SQL Keyword Checking
7327** These routines provide access to the set of SQL language keywords
7328** recognized by SQLite. Applications can uses these routines to determine
7329** whether or not a specific identifier needs to be escaped (for example,
7330** by enclosing in double-quotes) so as not to confuse the parser.
7332** The sqlite3_keyword_count() interface returns the number of distinct
7333** keywords understood by SQLite.
7335** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and
7336** makes *Z point to that keyword expressed as UTF8 and writes the number
7337** of bytes in the keyword into *L. The string that *Z points to is not
7338** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns
7339** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
7340** or L are NULL or invalid pointers then calls to
7341** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
7343** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
7344** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
7345** if it is and zero if not.
7347** The parser used by SQLite is forgiving. It is often possible to use
7348** a keyword as an identifier as long as such use does not result in a
7349** parsing ambiguity. For example, the statement
7350** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
7351** creates a new table named "BEGIN" with three columns named
7352** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid
7353** using keywords as identifiers. Common techniques used to avoid keyword
7354** name collisions include:
7355** <ul>
7356** <li> Put all identifier names inside double-quotes. This is the official
7357** SQL way to escape identifier names.
7358** <li> Put identifier names inside &#91;...&#93;. This is not standard SQL,
7359** but it is what SQL Server does and so lots of programmers use this
7360** technique.
7361** <li> Begin every identifier with the letter "Z" as no SQL keywords start
7362** with "Z".
7363** <li> Include a digit somewhere in every identifier name.
7364** </ul>
7366** Note that the number of keywords understood by SQLite can depend on
7367** compile-time options. For example, "VACUUM" is not a keyword if
7368** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also,
7369** new keywords may be added to future releases of SQLite.
7371SQLITE_API int sqlite3_keyword_count(void);
7372SQLITE_API int sqlite3_keyword_name(int,const char**,int*);
7373SQLITE_API int sqlite3_keyword_check(const char*,int);
7376** CAPI3REF: Dynamic String Object
7377** KEYWORDS: {dynamic string}
7379** An instance of the sqlite3_str object contains a dynamically-sized
7380** string under construction.
7382** The lifecycle of an sqlite3_str object is as follows:
7383** <ol>
7384** <li> ^The sqlite3_str object is created using [sqlite3_str_new()].
7385** <li> ^Text is appended to the sqlite3_str object using various
7386** methods, such as [sqlite3_str_appendf()].
7387** <li> ^The sqlite3_str object is destroyed and the string it created
7388** is returned using the [sqlite3_str_finish()] interface.
7389** </ol>
7391typedef struct sqlite3_str sqlite3_str;
7394** CAPI3REF: Create A New Dynamic String Object
7395** CONSTRUCTOR: sqlite3_str
7397** ^The [sqlite3_str_new(D)] interface allocates and initializes
7398** a new [sqlite3_str] object. To avoid memory leaks, the object returned by
7399** [sqlite3_str_new()] must be freed by a subsequent call to
7400** [sqlite3_str_finish(X)].
7402** ^The [sqlite3_str_new(D)] interface always returns a pointer to a
7403** valid [sqlite3_str] object, though in the event of an out-of-memory
7404** error the returned object might be a special singleton that will
7405** silently reject new text, always return SQLITE_NOMEM from
7406** [sqlite3_str_errcode()], always return 0 for
7407** [sqlite3_str_length()], and always return NULL from
7408** [sqlite3_str_finish(X)]. It is always safe to use the value
7409** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter
7410** to any of the other [sqlite3_str] methods.
7412** The D parameter to [sqlite3_str_new(D)] may be NULL. If the
7413** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum
7414** length of the string contained in the [sqlite3_str] object will be
7415** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead
7416** of [SQLITE_MAX_LENGTH].
7418SQLITE_API sqlite3_str *sqlite3_str_new(sqlite3*);
7421** CAPI3REF: Finalize A Dynamic String
7422** DESTRUCTOR: sqlite3_str
7424** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
7425** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
7426** that contains the constructed string. The calling application should
7427** pass the returned value to [sqlite3_free()] to avoid a memory leak.
7428** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
7429** errors were encountered during construction of the string. ^The
7430** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the
7431** string in [sqlite3_str] object X is zero bytes long.
7433SQLITE_API char *sqlite3_str_finish(sqlite3_str*);
7436** CAPI3REF: Add Content To A Dynamic String
7437** METHOD: sqlite3_str
7439** These interfaces add content to an sqlite3_str object previously obtained
7440** from [sqlite3_str_new()].
7442** ^The [sqlite3_str_appendf(X,F,...)] and
7443** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
7444** functionality of SQLite to append formatted text onto the end of
7445** [sqlite3_str] object X.
7447** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
7448** onto the end of the [sqlite3_str] object X. N must be non-negative.
7449** S must contain at least N non-zero bytes of content. To append a
7450** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
7451** method instead.
7453** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of
7454** zero-terminated string S onto the end of [sqlite3_str] object X.
7456** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
7457** single-byte character C onto the end of [sqlite3_str] object X.
7458** ^This method can be used, for example, to add whitespace indentation.
7460** ^The [sqlite3_str_reset(X)] method resets the string under construction
7461** inside [sqlite3_str] object X back to zero bytes in length.
7463** These methods do not return a result code. ^If an error occurs, that fact
7464** is recorded in the [sqlite3_str] object and can be recovered by a
7465** subsequent call to [sqlite3_str_errcode(X)].
7467SQLITE_API void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
7468SQLITE_API void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
7469SQLITE_API void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
7470SQLITE_API void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
7471SQLITE_API void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
7472SQLITE_API void sqlite3_str_reset(sqlite3_str*);
7475** CAPI3REF: Status Of A Dynamic String
7476** METHOD: sqlite3_str
7478** These interfaces return the current status of an [sqlite3_str] object.
7480** ^If any prior errors have occurred while constructing the dynamic string
7481** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
7482** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns
7483** [SQLITE_NOMEM] following any out-of-memory error, or
7484** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
7485** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
7487** ^The [sqlite3_str_length(X)] method returns the current length, in bytes,
7488** of the dynamic string under construction in [sqlite3_str] object X.
7489** ^The length returned by [sqlite3_str_length(X)] does not include the
7490** zero-termination byte.
7492** ^The [sqlite3_str_value(X)] method returns a pointer to the current
7493** content of the dynamic string under construction in X. The value
7494** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
7495** and might be freed or altered by any subsequent method on the same
7496** [sqlite3_str] object. Applications must not used the pointer returned
7497** [sqlite3_str_value(X)] after any subsequent method call on the same
7498** object. ^Applications may change the content of the string returned
7499** by [sqlite3_str_value(X)] as long as they do not write into any bytes
7500** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
7501** write any byte after any subsequent sqlite3_str method call.
7503SQLITE_API int sqlite3_str_errcode(sqlite3_str*);
7504SQLITE_API int sqlite3_str_length(sqlite3_str*);
7505SQLITE_API char *sqlite3_str_value(sqlite3_str*);
7508** CAPI3REF: SQLite Runtime Status
7510** ^These interfaces are used to retrieve runtime status information
7511** about the performance of SQLite, and optionally to reset various
7512** highwater marks. ^The first argument is an integer code for
7513** the specific parameter to measure. ^(Recognized integer codes
7514** are of the form [status parameters | SQLITE_STATUS_...].)^
7515** ^The current value of the parameter is returned into *pCurrent.
7516** ^The highest recorded value is returned in *pHighwater. ^If the
7517** resetFlag is true, then the highest record value is reset after
7518** *pHighwater is written. ^(Some parameters do not record the highest
7519** value. For those parameters
7520** nothing is written into *pHighwater and the resetFlag is ignored.)^
7521** ^(Other parameters record only the highwater mark and not the current
7522** value. For these latter parameters nothing is written into *pCurrent.)^
7524** ^The sqlite3_status() and sqlite3_status64() routines return
7525** SQLITE_OK on success and a non-zero [error code] on failure.
7527** If either the current value or the highwater mark is too large to
7528** be represented by a 32-bit integer, then the values returned by
7529** sqlite3_status() are undefined.
7531** See also: [sqlite3_db_status()]
7533SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
7534SQLITE_API int sqlite3_status64(
7535 int op,
7536 sqlite3_int64 *pCurrent,
7537 sqlite3_int64 *pHighwater,
7538 int resetFlag
7543** CAPI3REF: Status Parameters
7544** KEYWORDS: {status parameters}
7546** These integer constants designate various run-time status parameters
7547** that can be returned by [sqlite3_status()].
7549** <dl>
7551** <dd>This parameter is the current amount of memory checked out
7552** using [sqlite3_malloc()], either directly or indirectly. The
7553** figure includes calls made to [sqlite3_malloc()] by the application
7554** and internal memory usage by the SQLite library. Auxiliary page-cache
7555** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
7556** this parameter. The amount returned is the sum of the allocation
7557** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
7560** <dd>This parameter records the largest memory allocation request
7561** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
7562** internal equivalents). Only the value returned in the
7563** *pHighwater parameter to [sqlite3_status()] is of interest.
7564** The value written into the *pCurrent parameter is undefined.</dd>)^
7567** <dd>This parameter records the number of separate memory allocations
7568** currently checked out.</dd>)^
7571** <dd>This parameter returns the number of pages used out of the
7572** [pagecache memory allocator] that was configured using
7574** value returned is in pages, not in bytes.</dd>)^
7578** <dd>This parameter returns the number of bytes of page cache
7579** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
7580** buffer and where forced to overflow to [sqlite3_malloc()]. The
7581** returned value includes allocations that overflowed because they
7582** where too large (they were larger than the "sz" parameter to
7583** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
7584** no space was left in the page cache.</dd>)^
7587** <dd>This parameter records the largest memory allocation request
7588** handed to [pagecache memory allocator]. Only the value returned in the
7589** *pHighwater parameter to [sqlite3_status()] is of interest.
7590** The value written into the *pCurrent parameter is undefined.</dd>)^
7593** <dd>No longer used.</dd>
7596** <dd>No longer used.</dd>
7599** <dd>No longer used.</dd>
7602** <dd>The *pHighwater parameter records the deepest parser stack.
7603** The *pCurrent value is undefined. The *pHighwater value is only
7604** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
7605** </dl>
7607** New status parameters may be added from time to time.
7621** CAPI3REF: Database Connection Status
7622** METHOD: sqlite3
7624** ^This interface is used to retrieve runtime status information
7625** about a single [database connection]. ^The first argument is the
7626** database connection object to be interrogated. ^The second argument
7627** is an integer constant, taken from the set of
7628** [SQLITE_DBSTATUS options], that
7629** determines the parameter to interrogate. The set of
7630** [SQLITE_DBSTATUS options] is likely
7631** to grow in future releases of SQLite.
7633** ^The current value of the requested parameter is written into *pCur
7634** and the highest instantaneous value is written into *pHiwtr. ^If
7635** the resetFlg is true, then the highest instantaneous value is
7636** reset back down to the current value.
7638** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
7639** non-zero [error code] on failure.
7641** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
7643SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
7646** CAPI3REF: Status Parameters for database connections
7649** These constants are the available integer "verbs" that can be passed as
7650** the second argument to the [sqlite3_db_status()] interface.
7652** New verbs may be added in future releases of SQLite. Existing verbs
7653** might be discontinued. Applications should check the return code from
7654** [sqlite3_db_status()] to make sure that the call worked.
7655** The [sqlite3_db_status()] interface will return a non-zero error code
7656** if a discontinued or unsupported verb is invoked.
7658** <dl>
7660** <dd>This parameter returns the number of lookaside memory slots currently
7661** checked out.</dd>)^
7664** <dd>This parameter returns the number malloc attempts that were
7665** satisfied using lookaside memory. Only the high-water value is meaningful;
7666** the current value is always zero.)^
7670** <dd>This parameter returns the number malloc attempts that might have
7671** been satisfied using lookaside memory but failed due to the amount of
7672** memory requested being larger than the lookaside slot size.
7673** Only the high-water value is meaningful;
7674** the current value is always zero.)^
7678** <dd>This parameter returns the number malloc attempts that might have
7679** been satisfied using lookaside memory but failed due to all lookaside
7680** memory already being in use.
7681** Only the high-water value is meaningful;
7682** the current value is always zero.)^
7685** <dd>This parameter returns the approximate number of bytes of heap
7686** memory used by all pager caches associated with the database connection.)^
7687** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
7691** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
7692** pager cache is shared between two or more connections the bytes of heap
7693** memory used by that pager cache is divided evenly between the attached
7694** connections.)^ In other words, if none of the pager caches associated
7695** with the database connection are shared, this request returns the same
7696** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
7697** shared, the value returned by this call will be smaller than that returned
7698** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
7702** <dd>This parameter returns the approximate number of bytes of heap
7703** memory used to store the schema for all databases associated
7704** with the connection - main, temp, and any [ATTACH]-ed databases.)^
7705** ^The full amount of memory used by the schemas is reported, even if the
7706** schema memory is shared with other database connections due to
7707** [shared cache mode] being enabled.
7708** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
7711** <dd>This parameter returns the approximate number of bytes of heap
7712** and lookaside memory used by all prepared statements associated with
7713** the database connection.)^
7714** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
7715** </dd>
7718** <dd>This parameter returns the number of pager cache hits that have
7719** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
7720** is always 0.
7721** </dd>
7724** <dd>This parameter returns the number of pager cache misses that have
7725** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
7726** is always 0.
7727** </dd>
7730** <dd>This parameter returns the number of dirty cache entries that have
7731** been written to disk. Specifically, the number of pages written to the
7732** wal file in wal mode databases, or the number of pages written to the
7733** database file in rollback mode databases. Any pages written as part of
7734** transaction rollback or database recovery operations are not included.
7735** If an IO or other error occurs while writing a page to disk, the effect
7736** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
7737** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
7738** </dd>
7741** <dd>This parameter returns the number of dirty cache entries that have
7742** been written to disk in the middle of a transaction due to the page
7743** cache overflowing. Transactions are more efficient if they are written
7744** to disk all at once. When pages spill mid-transaction, that introduces
7745** additional overhead. This parameter can be used help identify
7746** inefficiencies that can be resolve by increasing the cache size.
7747** </dd>
7750** <dd>This parameter returns zero for the current value if and only if
7751** all foreign key constraints (deferred or immediate) have been
7752** resolved.)^ ^The highwater mark is always 0.
7753** </dd>
7754** </dl>
7769#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */
7773** CAPI3REF: Prepared Statement Status
7774** METHOD: sqlite3_stmt
7776** ^(Each prepared statement maintains various
7777** [SQLITE_STMTSTATUS counters] that measure the number
7778** of times it has performed specific operations.)^ These counters can
7779** be used to monitor the performance characteristics of the prepared
7780** statements. For example, if the number of table steps greatly exceeds
7781** the number of table searches or result rows, that would tend to indicate
7782** that the prepared statement is using a full table scan rather than
7783** an index.
7785** ^(This interface is used to retrieve and reset counter values from
7786** a [prepared statement]. The first argument is the prepared statement
7787** object to be interrogated. The second argument
7788** is an integer code for a specific [SQLITE_STMTSTATUS counter]
7789** to be interrogated.)^
7790** ^The current value of the requested counter is returned.
7791** ^If the resetFlg is true, then the counter is reset to zero after this
7792** interface call returns.
7794** See also: [sqlite3_status()] and [sqlite3_db_status()].
7796SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
7799** CAPI3REF: Status Parameters for prepared statements
7802** These preprocessor macros define integer codes that name counter
7803** values associated with the [sqlite3_stmt_status()] interface.
7804** The meanings of the various counters are as follows:
7806** <dl>
7808** <dd>^This is the number of times that SQLite has stepped forward in
7809** a table as part of a full table scan. Large numbers for this counter
7810** may indicate opportunities for performance improvement through
7811** careful use of indices.</dd>
7814** <dd>^This is the number of sort operations that have occurred.
7815** A non-zero value in this counter may indicate an opportunity to
7816** improvement performance through careful use of indices.</dd>
7819** <dd>^This is the number of rows inserted into transient indices that
7820** were created automatically in order to help joins run faster.
7821** A non-zero value in this counter may indicate an opportunity to
7822** improvement performance by adding permanent indices that do not
7823** need to be reinitialized each time the statement is run.</dd>
7826** <dd>^This is the number of virtual machine operations executed
7827** by the prepared statement if that number is less than or equal
7828** to 2147483647. The number of virtual machine operations can be
7829** used as a proxy for the total work done by the prepared statement.
7830** If the number of virtual machine operations exceeds 2147483647
7831** then the value returned by this statement status code is undefined.
7834** <dd>^This is the number of times that the prepare statement has been
7835** automatically regenerated due to schema changes or change to
7836** [bound parameters] that might affect the query plan.
7839** <dd>^This is the number of times that the prepared statement has
7840** been run. A single "run" for the purposes of this counter is one
7841** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
7842** The counter is incremented on the first [sqlite3_step()] call of each
7843** cycle.
7846** <dd>^This is the approximate number of bytes of heap memory
7847** used to store the prepared statement. ^This value is not actually
7848** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
7849** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
7850** </dd>
7851** </dl>
7862** CAPI3REF: Custom Page Cache Object
7864** The sqlite3_pcache type is opaque. It is implemented by
7865** the pluggable module. The SQLite core has no knowledge of
7866** its size or internal structure and never deals with the
7867** sqlite3_pcache object except by holding and passing pointers
7868** to the object.
7870** See [sqlite3_pcache_methods2] for additional information.
7872typedef struct sqlite3_pcache sqlite3_pcache;
7875** CAPI3REF: Custom Page Cache Object
7877** The sqlite3_pcache_page object represents a single page in the
7878** page cache. The page cache will allocate instances of this
7879** object. Various methods of the page cache use pointers to instances
7880** of this object as parameters or as their return value.
7882** See [sqlite3_pcache_methods2] for additional information.
7884typedef struct sqlite3_pcache_page sqlite3_pcache_page;
7885struct sqlite3_pcache_page {
7886 void *pBuf; /* The content of the page */
7887 void *pExtra; /* Extra information associated with the page */
7891** CAPI3REF: Application Defined Page Cache.
7892** KEYWORDS: {page cache}
7894** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
7895** register an alternative page cache implementation by passing in an
7896** instance of the sqlite3_pcache_methods2 structure.)^
7897** In many applications, most of the heap memory allocated by
7898** SQLite is used for the page cache.
7899** By implementing a
7900** custom page cache using this API, an application can better control
7901** the amount of memory consumed by SQLite, the way in which
7902** that memory is allocated and released, and the policies used to
7903** determine exactly which parts of a database file are cached and for
7904** how long.
7906** The alternative page cache mechanism is an
7907** extreme measure that is only needed by the most demanding applications.
7908** The built-in page cache is recommended for most uses.
7910** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
7911** internal buffer by SQLite within the call to [sqlite3_config]. Hence
7912** the application may discard the parameter after the call to
7913** [sqlite3_config()] returns.)^
7915** [[the xInit() page cache method]]
7916** ^(The xInit() method is called once for each effective
7917** call to [sqlite3_initialize()])^
7918** (usually only once during the lifetime of the process). ^(The xInit()
7919** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
7920** The intent of the xInit() method is to set up global data structures
7921** required by the custom page cache implementation.
7922** ^(If the xInit() method is NULL, then the
7923** built-in default page cache is used instead of the application defined
7924** page cache.)^
7926** [[the xShutdown() page cache method]]
7927** ^The xShutdown() method is called by [sqlite3_shutdown()].
7928** It can be used to clean up
7929** any outstanding resources before process shutdown, if required.
7930** ^The xShutdown() method may be NULL.
7932** ^SQLite automatically serializes calls to the xInit method,
7933** so the xInit method need not be threadsafe. ^The
7934** xShutdown method is only called from [sqlite3_shutdown()] so it does
7935** not need to be threadsafe either. All other methods must be threadsafe
7936** in multithreaded applications.
7938** ^SQLite will never invoke xInit() more than once without an intervening
7939** call to xShutdown().
7941** [[the xCreate() page cache methods]]
7942** ^SQLite invokes the xCreate() method to construct a new cache instance.
7943** SQLite will typically create one cache instance for each open database file,
7944** though this is not guaranteed. ^The
7945** first parameter, szPage, is the size in bytes of the pages that must
7946** be allocated by the cache. ^szPage will always a power of two. ^The
7947** second parameter szExtra is a number of bytes of extra storage
7948** associated with each page cache entry. ^The szExtra parameter will
7949** a number less than 250. SQLite will use the
7950** extra szExtra bytes on each page to store metadata about the underlying
7951** database page on disk. The value passed into szExtra depends
7952** on the SQLite version, the target platform, and how SQLite was compiled.
7953** ^The third argument to xCreate(), bPurgeable, is true if the cache being
7954** created will be used to cache database pages of a file stored on disk, or
7955** false if it is used for an in-memory database. The cache implementation
7956** does not have to do anything special based with the value of bPurgeable;
7957** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
7958** never invoke xUnpin() except to deliberately delete a page.
7959** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
7960** false will always have the "discard" flag set to true.
7961** ^Hence, a cache created with bPurgeable false will
7962** never contain any unpinned pages.
7964** [[the xCachesize() page cache method]]
7965** ^(The xCachesize() method may be called at any time by SQLite to set the
7966** suggested maximum cache-size (number of pages stored by) the cache
7967** instance passed as the first argument. This is the value configured using
7968** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
7969** parameter, the implementation is not required to do anything with this
7970** value; it is advisory only.
7972** [[the xPagecount() page cache methods]]
7973** The xPagecount() method must return the number of pages currently
7974** stored in the cache, both pinned and unpinned.
7976** [[the xFetch() page cache methods]]
7977** The xFetch() method locates a page in the cache and returns a pointer to
7978** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
7979** The pBuf element of the returned sqlite3_pcache_page object will be a
7980** pointer to a buffer of szPage bytes used to store the content of a
7981** single database page. The pExtra element of sqlite3_pcache_page will be
7982** a pointer to the szExtra bytes of extra storage that SQLite has requested
7983** for each entry in the page cache.
7985** The page to be fetched is determined by the key. ^The minimum key value
7986** is 1. After it has been retrieved using xFetch, the page is considered
7987** to be "pinned".
7989** If the requested page is already in the page cache, then the page cache
7990** implementation must return a pointer to the page buffer with its content
7991** intact. If the requested page is not already in the cache, then the
7992** cache implementation should use the value of the createFlag
7993** parameter to help it determined what action to take:
7995** <table border=1 width=85% align=center>
7996** <tr><th> createFlag <th> Behavior when page is not already in cache
7997** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
7998** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
7999** Otherwise return NULL.
8000** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
8001** NULL if allocating a new page is effectively impossible.
8002** </table>
8004** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
8005** will only use a createFlag of 2 after a prior call with a createFlag of 1
8006** failed.)^ In between the to xFetch() calls, SQLite may
8007** attempt to unpin one or more cache pages by spilling the content of
8008** pinned pages to disk and synching the operating system disk cache.
8010** [[the xUnpin() page cache method]]
8011** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
8012** as its second argument. If the third parameter, discard, is non-zero,
8013** then the page must be evicted from the cache.
8014** ^If the discard parameter is
8015** zero, then the page may be discarded or retained at the discretion of
8016** page cache implementation. ^The page cache implementation
8017** may choose to evict unpinned pages at any time.
8019** The cache must not perform any reference counting. A single
8020** call to xUnpin() unpins the page regardless of the number of prior calls
8021** to xFetch().
8023** [[the xRekey() page cache methods]]
8024** The xRekey() method is used to change the key value associated with the
8025** page passed as the second argument. If the cache
8026** previously contains an entry associated with newKey, it must be
8027** discarded. ^Any prior cache entry associated with newKey is guaranteed not
8028** to be pinned.
8030** When SQLite calls the xTruncate() method, the cache must discard all
8031** existing cache entries with page numbers (keys) greater than or equal
8032** to the value of the iLimit parameter passed to xTruncate(). If any
8033** of these pages are pinned, they are implicitly unpinned, meaning that
8034** they can be safely discarded.
8036** [[the xDestroy() page cache method]]
8037** ^The xDestroy() method is used to delete a cache allocated by xCreate().
8038** All resources associated with the specified cache should be freed. ^After
8039** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
8040** handle invalid, and will not use it with any other sqlite3_pcache_methods2
8041** functions.
8043** [[the xShrink() page cache method]]
8044** ^SQLite invokes the xShrink() method when it wants the page cache to
8045** free up as much of heap memory as possible. The page cache implementation
8046** is not obligated to free any memory, but well-behaved implementations should
8047** do their best.
8049typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
8050struct sqlite3_pcache_methods2 {
8051 int iVersion;
8052 void *pArg;
8053 int (*xInit)(void*);
8054 void (*xShutdown)(void*);
8055 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
8056 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
8057 int (*xPagecount)(sqlite3_pcache*);
8058 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
8059 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
8060 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
8061 unsigned oldKey, unsigned newKey);
8062 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
8063 void (*xDestroy)(sqlite3_pcache*);
8064 void (*xShrink)(sqlite3_pcache*);
8068** This is the obsolete pcache_methods object that has now been replaced
8069** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
8070** retained in the header file for backwards compatibility only.
8072typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
8073struct sqlite3_pcache_methods {
8074 void *pArg;
8075 int (*xInit)(void*);
8076 void (*xShutdown)(void*);
8077 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
8078 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
8079 int (*xPagecount)(sqlite3_pcache*);
8080 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
8081 void (*xUnpin)(sqlite3_pcache*, void*, int discard);
8082 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
8083 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
8084 void (*xDestroy)(sqlite3_pcache*);
8089** CAPI3REF: Online Backup Object
8091** The sqlite3_backup object records state information about an ongoing
8092** online backup operation. ^The sqlite3_backup object is created by
8093** a call to [sqlite3_backup_init()] and is destroyed by a call to
8094** [sqlite3_backup_finish()].
8096** See Also: [Using the SQLite Online Backup API]
8098typedef struct sqlite3_backup sqlite3_backup;
8101** CAPI3REF: Online Backup API.
8103** The backup API copies the content of one database into another.
8104** It is useful either for creating backups of databases or
8105** for copying in-memory databases to or from persistent files.
8107** See Also: [Using the SQLite Online Backup API]
8109** ^SQLite holds a write transaction open on the destination database file
8110** for the duration of the backup operation.
8111** ^The source database is read-locked only while it is being read;
8112** it is not locked continuously for the entire backup operation.
8113** ^Thus, the backup may be performed on a live source database without
8114** preventing other database connections from
8115** reading or writing to the source database while the backup is underway.
8117** ^(To perform a backup operation:
8118** <ol>
8119** <li><b>sqlite3_backup_init()</b> is called once to initialize the
8120** backup,
8121** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
8122** the data between the two databases, and finally
8123** <li><b>sqlite3_backup_finish()</b> is called to release all resources
8124** associated with the backup operation.
8125** </ol>)^
8126** There should be exactly one call to sqlite3_backup_finish() for each
8127** successful call to sqlite3_backup_init().
8129** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
8131** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
8132** [database connection] associated with the destination database
8133** and the database name, respectively.
8134** ^The database name is "main" for the main database, "temp" for the
8135** temporary database, or the name specified after the AS keyword in
8136** an [ATTACH] statement for an attached database.
8137** ^The S and M arguments passed to
8138** sqlite3_backup_init(D,N,S,M) identify the [database connection]
8139** and database name of the source database, respectively.
8140** ^The source and destination [database connections] (parameters S and D)
8141** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
8142** an error.
8144** ^A call to sqlite3_backup_init() will fail, returning NULL, if
8145** there is already a read or read-write transaction open on the
8146** destination database.
8148** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
8149** returned and an error code and error message are stored in the
8150** destination [database connection] D.
8151** ^The error code and message for the failed call to sqlite3_backup_init()
8152** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
8153** [sqlite3_errmsg16()] functions.
8154** ^A successful call to sqlite3_backup_init() returns a pointer to an
8155** [sqlite3_backup] object.
8156** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
8157** sqlite3_backup_finish() functions to perform the specified backup
8158** operation.
8160** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
8162** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
8163** the source and destination databases specified by [sqlite3_backup] object B.
8164** ^If N is negative, all remaining source pages are copied.
8165** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
8166** are still more pages to be copied, then the function returns [SQLITE_OK].
8167** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
8168** from source to destination, then it returns [SQLITE_DONE].
8169** ^If an error occurs while running sqlite3_backup_step(B,N),
8170** then an [error code] is returned. ^As well as [SQLITE_OK] and
8171** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
8173** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
8175** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
8176** <ol>
8177** <li> the destination database was opened read-only, or
8178** <li> the destination database is using write-ahead-log journaling
8179** and the destination and source page sizes differ, or
8180** <li> the destination database is an in-memory database and the
8181** destination and source page sizes differ.
8182** </ol>)^
8184** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
8185** the [sqlite3_busy_handler | busy-handler function]
8186** is invoked (if one is specified). ^If the
8187** busy-handler returns non-zero before the lock is available, then
8188** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
8189** sqlite3_backup_step() can be retried later. ^If the source
8190** [database connection]
8191** is being used to write to the source database when sqlite3_backup_step()
8192** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
8193** case the call to sqlite3_backup_step() can be retried later on. ^(If
8195** [SQLITE_READONLY] is returned, then
8196** there is no point in retrying the call to sqlite3_backup_step(). These
8197** errors are considered fatal.)^ The application must accept
8198** that the backup operation has failed and pass the backup operation handle
8199** to the sqlite3_backup_finish() to release associated resources.
8201** ^The first call to sqlite3_backup_step() obtains an exclusive lock
8202** on the destination file. ^The exclusive lock is not released until either
8203** sqlite3_backup_finish() is called or the backup operation is complete
8204** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
8205** sqlite3_backup_step() obtains a [shared lock] on the source database that
8206** lasts for the duration of the sqlite3_backup_step() call.
8207** ^Because the source database is not locked between calls to
8208** sqlite3_backup_step(), the source database may be modified mid-way
8209** through the backup process. ^If the source database is modified by an
8210** external process or via a database connection other than the one being
8211** used by the backup operation, then the backup will be automatically
8212** restarted by the next call to sqlite3_backup_step(). ^If the source
8213** database is modified by the using the same database connection as is used
8214** by the backup operation, then the backup database is automatically
8215** updated at the same time.
8217** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
8219** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
8220** application wishes to abandon the backup operation, the application
8221** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
8222** ^The sqlite3_backup_finish() interfaces releases all
8223** resources associated with the [sqlite3_backup] object.
8224** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
8225** active write-transaction on the destination database is rolled back.
8226** The [sqlite3_backup] object is invalid
8227** and may not be used following a call to sqlite3_backup_finish().
8229** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
8230** sqlite3_backup_step() errors occurred, regardless or whether or not
8231** sqlite3_backup_step() completed.
8232** ^If an out-of-memory condition or IO error occurred during any prior
8233** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
8234** sqlite3_backup_finish() returns the corresponding [error code].
8236** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
8237** is not a permanent error and does not affect the return value of
8238** sqlite3_backup_finish().
8240** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
8241** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
8243** ^The sqlite3_backup_remaining() routine returns the number of pages still
8244** to be backed up at the conclusion of the most recent sqlite3_backup_step().
8245** ^The sqlite3_backup_pagecount() routine returns the total number of pages
8246** in the source database at the conclusion of the most recent
8247** sqlite3_backup_step().
8248** ^(The values returned by these functions are only updated by
8249** sqlite3_backup_step(). If the source database is modified in a way that
8250** changes the size of the source database or the number of pages remaining,
8251** those changes are not reflected in the output of sqlite3_backup_pagecount()
8252** and sqlite3_backup_remaining() until after the next
8253** sqlite3_backup_step().)^
8255** <b>Concurrent Usage of Database Handles</b>
8257** ^The source [database connection] may be used by the application for other
8258** purposes while a backup operation is underway or being initialized.
8259** ^If SQLite is compiled and configured to support threadsafe database
8260** connections, then the source database connection may be used concurrently
8261** from within other threads.
8263** However, the application must guarantee that the destination
8264** [database connection] is not passed to any other API (by any thread) after
8265** sqlite3_backup_init() is called and before the corresponding call to
8266** sqlite3_backup_finish(). SQLite does not currently check to see
8267** if the application incorrectly accesses the destination [database connection]
8268** and so no error code is reported, but the operations may malfunction
8269** nevertheless. Use of the destination database connection while a
8270** backup is in progress might also also cause a mutex deadlock.
8272** If running in [shared cache mode], the application must
8273** guarantee that the shared cache used by the destination database
8274** is not accessed while the backup is running. In practice this means
8275** that the application must guarantee that the disk file being
8276** backed up to is not accessed by any connection within the process,
8277** not just the specific connection that was passed to sqlite3_backup_init().
8279** The [sqlite3_backup] object itself is partially threadsafe. Multiple
8280** threads may safely make multiple concurrent calls to sqlite3_backup_step().
8281** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
8282** APIs are not strictly speaking threadsafe. If they are invoked at the
8283** same time as another thread is invoking sqlite3_backup_step() it is
8284** possible that they return invalid values.
8286SQLITE_API sqlite3_backup *sqlite3_backup_init(
8287 sqlite3 *pDest, /* Destination database handle */
8288 const char *zDestName, /* Destination database name */
8289 sqlite3 *pSource, /* Source database handle */
8290 const char *zSourceName /* Source database name */
8292SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
8293SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
8294SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
8295SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
8298** CAPI3REF: Unlock Notification
8299** METHOD: sqlite3
8301** ^When running in shared-cache mode, a database operation may fail with
8302** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
8303** individual tables within the shared-cache cannot be obtained. See
8304** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
8305** ^This API may be used to register a callback that SQLite will invoke
8306** when the connection currently holding the required lock relinqui