1/*
2** 2001-09-15
3**
4** The author disclaims copyright to this source code. In place of
5** a legal notice, here is a blessing:
6**
7** May you do good and not evil.
8** May you find forgiveness for yourself and forgive others.
9** May you share freely, never taking more than you give.
10**
11*************************************************************************
12** This header file defines the interface that the SQLite library
13** presents to client programs. If a C-function, structure, datatype,
14** or constant definition does not appear in this file, then it is
15** not a published API of SQLite, is subject to change without
16** notice, and should not be referenced by programs that use SQLite.
17**
18** Some of the definitions that are in this file are marked as
19** "experimental". Experimental interfaces are normally new
20** features recently added to SQLite. We do not anticipate changes
21** to experimental interfaces but reserve the right to make minor changes
22** if experience from use "in the wild" suggest such changes are prudent.
23**
24** The official C-language API documentation for SQLite is derived
25** from comments in this file. This file is the authoritative source
26** on how SQLite interfaces are supposed to operate.
27**
28** The name of this file under configuration management is "sqlite.h.in".
29** The makefile makes some minor changes to this file (such as inserting
30** the version number) and changes its name to "sqlite3.h" as
31** part of the build process.
32*/
33#ifndef SQLITE3_H
34#define SQLITE3_H
35#include <stdarg.h> /* Needed for the definition of va_list */
36
37/*
38** Make sure we can call this stuff from C++.
39*/
40#ifdef __cplusplus
41extern "C" {
42#endif
43
44
45/*
46** Provide the ability to override linkage features of the interface.
47*/
48#ifndef SQLITE_EXTERN
49# define SQLITE_EXTERN extern
50#endif
51#ifndef SQLITE_API
52# define SQLITE_API
53#endif
54#ifndef SQLITE_CDECL
55# define SQLITE_CDECL
56#endif
57#ifndef SQLITE_APICALL
58# define SQLITE_APICALL
59#endif
60#ifndef SQLITE_STDCALL
61# define SQLITE_STDCALL SQLITE_APICALL
62#endif
63#ifndef SQLITE_CALLBACK
64# define SQLITE_CALLBACK
65#endif
66#ifndef SQLITE_SYSAPI
67# define SQLITE_SYSAPI
68#endif
69
70/*
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.
76**
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.
82*/
83#define SQLITE_DEPRECATED
84#define SQLITE_EXPERIMENTAL
85
86/*
87** Ensure these symbols were not defined by some previous header file.
88*/
89#ifdef SQLITE_VERSION
90# undef SQLITE_VERSION
91#endif
92#ifdef SQLITE_VERSION_NUMBER
93# undef SQLITE_VERSION_NUMBER
94#endif
95
96/*
97** CAPI3REF: Compile-Time Library Version Numbers
98**
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.
110**
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.
121**
122** See also: [sqlite3_libversion()],
123** [sqlite3_libversion_number()], [sqlite3_sourceid()],
124** [sqlite_version()] and [sqlite_source_id()].
125*/
126#define SQLITE_VERSION "3.22.0"
127#define SQLITE_VERSION_NUMBER 3022000
128#define SQLITE_SOURCE_ID "2018-01-22 18:45:57 0c55d179733b46d8d0ba4d88e01a25e10677046ee3da1d5b1581e86726f2alt1"
129
130/*
131** CAPI3REF: Run-Time Library Version Numbers
132** KEYWORDS: sqlite3_version sqlite3_sourceid
133**
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.
141**
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>)^
147**
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].)^
159**
160** See also: [sqlite_version()] and [sqlite_source_id()].
161*/
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);
166
167/*
168** CAPI3REF: Run-Time Library Compilation Options Diagnostics
169**
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().
174**
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().
181**
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.
185**
186** See also: SQL functions [sqlite_compileoption_used()] and
187** [sqlite_compileoption_get()] and the [compile_options pragma].
188*/
189#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
190SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
191SQLITE_API const char *sqlite3_compileoption_get(int N);
192#endif
193
194/*
195** CAPI3REF: Test To See If The Library Is Threadsafe
196**
197** ^The sqlite3_threadsafe() function returns zero if and only if
198** SQLite was compiled with mutexing code omitted due to the
199** [SQLITE_THREADSAFE] compile-time option being set to 0.
200**
201** SQLite can be compiled with or without mutexes. When
202** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
203** are enabled and SQLite is threadsafe. When the
204** [SQLITE_THREADSAFE] macro is 0,
205** the mutexes are omitted. Without the mutexes, it is not safe
206** to use SQLite concurrently from more than one thread.
207**
208** Enabling mutexes incurs a measurable performance penalty.
209** So if speed is of utmost importance, it makes sense to disable
210** the mutexes. But for maximum safety, mutexes should be enabled.
211** ^The default behavior is for mutexes to be enabled.
212**
213** This interface can be used by an application to make sure that the
214** version of SQLite that it is linking against was compiled with
215** the desired setting of the [SQLITE_THREADSAFE] macro.
216**
217** This interface only reports on the compile-time mutex setting
218** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
219** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
220** can be fully or partially disabled using a call to [sqlite3_config()]
221** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
222** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the
223** sqlite3_threadsafe() function shows only the compile-time setting of
224** thread safety, not any run-time changes to that setting made by
225** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
226** is unchanged by calls to sqlite3_config().)^
227**
228** See the [threading mode] documentation for additional information.
229*/
230SQLITE_API int sqlite3_threadsafe(void);
231
232/*
233** CAPI3REF: Database Connection Handle
234** KEYWORDS: {database connection} {database connections}
235**
236** Each open SQLite database is represented by a pointer to an instance of
237** the opaque structure named "sqlite3". It is useful to think of an sqlite3
238** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
239** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
240** and [sqlite3_close_v2()] are its destructors. There are many other
241** interfaces (such as
242** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
243** [sqlite3_busy_timeout()] to name but three) that are methods on an
244** sqlite3 object.
245*/
246typedef struct sqlite3 sqlite3;
247
248/*
249** CAPI3REF: 64-Bit Integer Types
250** KEYWORDS: sqlite_int64 sqlite_uint64
251**
252** Because there is no cross-platform way to specify 64-bit integer types
253** SQLite includes typedefs for 64-bit signed and unsigned integers.
254**
255** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
256** The sqlite_int64 and sqlite_uint64 types are supported for backwards
257** compatibility only.
258**
259** ^The sqlite3_int64 and sqlite_int64 types can store integer values
260** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
261** sqlite3_uint64 and sqlite_uint64 types can store integer values
262** between 0 and +18446744073709551615 inclusive.
263*/
264#ifdef SQLITE_INT64_TYPE
265 typedef SQLITE_INT64_TYPE sqlite_int64;
266# ifdef SQLITE_UINT64_TYPE
267 typedef SQLITE_UINT64_TYPE sqlite_uint64;
268# else
269 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
270# endif
271#elif defined(_MSC_VER) || defined(__BORLANDC__)
272 typedef __int64 sqlite_int64;
273 typedef unsigned __int64 sqlite_uint64;
274#else
275 typedef long long int sqlite_int64;
276 typedef unsigned long long int sqlite_uint64;
277#endif
278typedef sqlite_int64 sqlite3_int64;
279typedef sqlite_uint64 sqlite3_uint64;
280
281/*
282** If compiling for a processor that lacks floating point support,
283** substitute integer for floating-point.
284*/
285#ifdef SQLITE_OMIT_FLOATING_POINT
286# define double sqlite3_int64
287#endif
288
289/*
290** CAPI3REF: Closing A Database Connection
291** DESTRUCTOR: sqlite3
292**
293** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
294** for the [sqlite3] object.
295** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
296** the [sqlite3] object is successfully destroyed and all associated
297** resources are deallocated.
298**
299** ^If the database connection is associated with unfinalized prepared
300** statements or unfinished sqlite3_backup objects then sqlite3_close()
301** will leave the database connection open and return [SQLITE_BUSY].
302** ^If sqlite3_close_v2() is called with unfinalized prepared statements
303** and/or unfinished sqlite3_backups, then the database connection becomes
304** an unusable "zombie" which will automatically be deallocated when the
305** last prepared statement is finalized or the last sqlite3_backup is
306** finished. The sqlite3_close_v2() interface is intended for use with
307** host languages that are garbage collected, and where the order in which
308** destructors are called is arbitrary.
309**
310** Applications should [sqlite3_finalize | finalize] all [prepared statements],
311** [sqlite3_blob_close | close] all [BLOB handles], and
312** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
313** with the [sqlite3] object prior to attempting to close the object. ^If
314** sqlite3_close_v2() is called on a [database connection] that still has
315** outstanding [prepared statements], [BLOB handles], and/or
316** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
317** of resources is deferred until all [prepared statements], [BLOB handles],
318** and [sqlite3_backup] objects are also destroyed.
319**
320** ^If an [sqlite3] object is destroyed while a transaction is open,
321** the transaction is automatically rolled back.
322**
323** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
324** must be either a NULL
325** pointer or an [sqlite3] object pointer obtained
326** from [sqlite3_open()], [sqlite3_open16()], or
327** [sqlite3_open_v2()], and not previously closed.
328** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
329** argument is a harmless no-op.
330*/
331SQLITE_API int sqlite3_close(sqlite3*);
332SQLITE_API int sqlite3_close_v2(sqlite3*);
333
334/*
335** The type for a callback function.
336** This is legacy and deprecated. It is included for historical
337** compatibility and is not documented.
338*/
339typedef int (*sqlite3_callback)(void*,int,char**, char**);
340
341/*
342** CAPI3REF: One-Step Query Execution Interface
343** METHOD: sqlite3
344**
345** The sqlite3_exec() interface is a convenience wrapper around
346** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
347** that allows an application to run multiple statements of SQL
348** without having to use a lot of C code.
349**
350** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
351** semicolon-separate SQL statements passed into its 2nd argument,
352** in the context of the [database connection] passed in as its 1st
353** argument. ^If the callback function of the 3rd argument to
354** sqlite3_exec() is not NULL, then it is invoked for each result row
355** coming out of the evaluated SQL statements. ^The 4th argument to
356** sqlite3_exec() is relayed through to the 1st argument of each
357** callback invocation. ^If the callback pointer to sqlite3_exec()
358** is NULL, then no callback is ever invoked and result rows are
359** ignored.
360**
361** ^If an error occurs while evaluating the SQL statements passed into
362** sqlite3_exec(), then execution of the current statement stops and
363** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
364** is not NULL then any error message is written into memory obtained
365** from [sqlite3_malloc()] and passed back through the 5th parameter.
366** To avoid memory leaks, the application should invoke [sqlite3_free()]
367** on error message strings returned through the 5th parameter of
368** sqlite3_exec() after the error message string is no longer needed.
369** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
370** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
371** NULL before returning.
372**
373** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
374** routine returns SQLITE_ABORT without invoking the callback again and
375** without running any subsequent SQL statements.
376**
377** ^The 2nd argument to the sqlite3_exec() callback function is the
378** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
379** callback is an array of pointers to strings obtained as if from
380** [sqlite3_column_text()], one for each column. ^If an element of a
381** result row is NULL then the corresponding string pointer for the
382** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
383** sqlite3_exec() callback is an array of pointers to strings where each
384** entry represents the name of corresponding result column as obtained
385** from [sqlite3_column_name()].
386**
387** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
388** to an empty string, or a pointer that contains only whitespace and/or
389** SQL comments, then no SQL statements are evaluated and the database
390** is not changed.
391**
392** Restrictions:
393**
394** <ul>
395** <li> The application must ensure that the 1st parameter to sqlite3_exec()
396** is a valid and open [database connection].
397** <li> The application must not close the [database connection] specified by
398** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
399** <li> The application must not modify the SQL statement text passed into
400** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
401** </ul>
402*/
403SQLITE_API int sqlite3_exec(
404 sqlite3*, /* An open database */
405 const char *sql, /* SQL to be evaluated */
406 int (*callback)(void*,int,char**,char**), /* Callback function */
407 void *, /* 1st argument to callback */
408 char **errmsg /* Error msg written here */
409);
410
411/*
412** CAPI3REF: Result Codes
413** KEYWORDS: {result code definitions}
414**
415** Many SQLite functions return an integer result code from the set shown
416** here in order to indicate success or failure.
417**
418** New error codes may be added in future versions of SQLite.
419**
420** See also: [extended result code definitions]
421*/
422#define SQLITE_OK 0 /* Successful result */
423/* beginning-of-error-codes */
424#define SQLITE_ERROR 1 /* Generic error */
425#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
426#define SQLITE_PERM 3 /* Access permission denied */
427#define SQLITE_ABORT 4 /* Callback routine requested an abort */
428#define SQLITE_BUSY 5 /* The database file is locked */
429#define SQLITE_LOCKED 6 /* A table in the database is locked */
430#define SQLITE_NOMEM 7 /* A malloc() failed */
431#define SQLITE_READONLY 8 /* Attempt to write a readonly database */
432#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
433#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
434#define SQLITE_CORRUPT 11 /* The database disk image is malformed */
435#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
436#define SQLITE_FULL 13 /* Insertion failed because database is full */
437#define SQLITE_CANTOPEN 14 /* Unable to open the database file */
438#define SQLITE_PROTOCOL 15 /* Database lock protocol error */
439#define SQLITE_EMPTY 16 /* Internal use only */
440#define SQLITE_SCHEMA 17 /* The database schema changed */
441#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
442#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
443#define SQLITE_MISMATCH 20 /* Data type mismatch */
444#define SQLITE_MISUSE 21 /* Library used incorrectly */
445#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
446#define SQLITE_AUTH 23 /* Authorization denied */
447#define SQLITE_FORMAT 24 /* Not used */
448#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
449#define SQLITE_NOTADB 26 /* File opened that is not a database file */
450#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */
451#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */
452#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
453#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
454/* end-of-error-codes */
455
456/*
457** CAPI3REF: Extended Result Codes
458** KEYWORDS: {extended result code definitions}
459**
460** In its default configuration, SQLite API routines return one of 30 integer
461** [result codes]. However, experience has shown that many of
462** these result codes are too coarse-grained. They do not provide as
463** much information about problems as programmers might like. In an effort to
464** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
465** and later) include
466** support for additional result codes that provide more detailed information
467** about errors. These [extended result codes] are enabled or disabled
468** on a per database connection basis using the
469** [sqlite3_extended_result_codes()] API. Or, the extended code for
470** the most recent error can be obtained using
471** [sqlite3_extended_errcode()].
472*/
473#define SQLITE_ERROR_MISSING_COLLSEQ (SQLITE_ERROR | (1<<8))
474#define SQLITE_ERROR_RETRY (SQLITE_ERROR | (2<<8))
475#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
476#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
477#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
478#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
479#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
480#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
481#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
482#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
483#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
484#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
485#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
486#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
487#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
488#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
489#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
490#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
491#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
492#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
493#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
494#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
495#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
496#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
497#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
498#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
499#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8))
500#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8))
501#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8))
502#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8))
503#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8))
504#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8))
505#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8))
506#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
507#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
508#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8))
509#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
510#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
511#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
512#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8))
513#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
514#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
515#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
516#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8))
517#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8))
518#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8))
519#define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8))
520#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
521#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8))
522#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8))
523#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8))
524#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8))
525#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8))
526#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8))
527#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8))
528#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8))
529#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8))
530#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8))
531#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8))
532#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
533#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8))
534#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8))
535#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8))
536
537/*
538** CAPI3REF: Flags For File Open Operations
539**
540** These bit values are intended for use in the
541** 3rd parameter to the [sqlite3_open_v2()] interface and
542** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
543*/
544#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
545#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
546#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
547#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
548#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
549#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
550#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
551#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
552#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
553#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
554#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
555#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
556#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
557#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
558#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
559#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
560#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
561#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
562#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
563#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
564
565/* Reserved: 0x00F00000 */
566
567/*
568** CAPI3REF: Device Characteristics
569**
570** The xDeviceCharacteristics method of the [sqlite3_io_methods]
571** object returns an integer which is a vector of these
572** bit values expressing I/O characteristics of the mass storage
573** device that holds the file that the [sqlite3_io_methods]
574** refers to.
575**
576** The SQLITE_IOCAP_ATOMIC property means that all writes of
577** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
578** mean that writes of blocks that are nnn bytes in size and
579** are aligned to an address which is an integer multiple of
580** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
581** that when data is appended to a file, the data is appended
582** first then the size of the file is extended, never the other
583** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
584** information is written to disk in the same order as calls
585** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
586** after reboot following a crash or power loss, the only bytes in a
587** file that were written at the application level might have changed
588** and that adjacent bytes, even bytes within the same sector are
589** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
590** flag indicates that a file cannot be deleted when open. The
591** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
592** read-only media and cannot be changed even by processes with
593** elevated privileges.
594**
595** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
596** filesystem supports doing multiple write operations atomically when those
597** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
598** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
599*/
600#define SQLITE_IOCAP_ATOMIC 0x00000001
601#define SQLITE_IOCAP_ATOMIC512 0x00000002
602#define SQLITE_IOCAP_ATOMIC1K 0x00000004
603#define SQLITE_IOCAP_ATOMIC2K 0x00000008
604#define SQLITE_IOCAP_ATOMIC4K 0x00000010
605#define SQLITE_IOCAP_ATOMIC8K 0x00000020
606#define SQLITE_IOCAP_ATOMIC16K 0x00000040
607#define SQLITE_IOCAP_ATOMIC32K 0x00000080
608#define SQLITE_IOCAP_ATOMIC64K 0x00000100
609#define SQLITE_IOCAP_SAFE_APPEND 0x00000200
610#define SQLITE_IOCAP_SEQUENTIAL 0x00000400
611#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
612#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
613#define SQLITE_IOCAP_IMMUTABLE 0x00002000
614#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000
615
616/*
617** CAPI3REF: File Locking Levels
618**
619** SQLite uses one of these integer values as the second
620** argument to calls it makes to the xLock() and xUnlock() methods
621** of an [sqlite3_io_methods] object.
622*/
623#define SQLITE_LOCK_NONE 0
624#define SQLITE_LOCK_SHARED 1
625#define SQLITE_LOCK_RESERVED 2
626#define SQLITE_LOCK_PENDING 3
627#define SQLITE_LOCK_EXCLUSIVE 4
628
629/*
630** CAPI3REF: Synchronization Type Flags
631**
632** When SQLite invokes the xSync() method of an
633** [sqlite3_io_methods] object it uses a combination of
634** these integer values as the second argument.
635**
636** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
637** sync operation only needs to flush data to mass storage. Inode
638** information need not be flushed. If the lower four bits of the flag
639** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
640** If the lower four bits equal SQLITE_SYNC_FULL, that means
641** to use Mac OS X style fullsync instead of fsync().
642**
643** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
644** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
645** settings. The [synchronous pragma] determines when calls to the
646** xSync VFS method occur and applies uniformly across all platforms.
647** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
648** energetic or rigorous or forceful the sync operations are and
649** only make a difference on Mac OSX for the default SQLite code.
650** (Third-party VFS implementations might also make the distinction
651** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
652** operating systems natively supported by SQLite, only Mac OSX
653** cares about the difference.)
654*/
655#define SQLITE_SYNC_NORMAL 0x00002
656#define SQLITE_SYNC_FULL 0x00003
657#define SQLITE_SYNC_DATAONLY 0x00010
658
659/*
660** CAPI3REF: OS Interface Open File Handle
661**
662** An [sqlite3_file] object represents an open file in the
663** [sqlite3_vfs | OS interface layer]. Individual OS interface
664** implementations will
665** want to subclass this object by appending additional fields
666** for their own use. The pMethods entry is a pointer to an
667** [sqlite3_io_methods] object that defines methods for performing
668** I/O operations on the open file.
669*/
670typedef struct sqlite3_file sqlite3_file;
671struct sqlite3_file {
672 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
673};
674
675/*
676** CAPI3REF: OS Interface File Virtual Methods Object
677**
678** Every file opened by the [sqlite3_vfs.xOpen] method populates an
679** [sqlite3_file] object (or, more commonly, a subclass of the
680** [sqlite3_file] object) with a pointer to an instance of this object.
681** This object defines the methods used to perform various operations
682** against the open file represented by the [sqlite3_file] object.
683**
684** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
685** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
686** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
687** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
688** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
689** to NULL.
690**
691** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
692** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
693** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
694** flag may be ORed in to indicate that only the data of the file
695** and not its inode needs to be synced.
696**
697** The integer values to xLock() and xUnlock() are one of
698** <ul>
699** <li> [SQLITE_LOCK_NONE],
700** <li> [SQLITE_LOCK_SHARED],
701** <li> [SQLITE_LOCK_RESERVED],
702** <li> [SQLITE_LOCK_PENDING], or
703** <li> [SQLITE_LOCK_EXCLUSIVE].
704** </ul>
705** xLock() increases the lock. xUnlock() decreases the lock.
706** The xCheckReservedLock() method checks whether any database connection,
707** either in this process or in some other process, is holding a RESERVED,
708** PENDING, or EXCLUSIVE lock on the file. It returns true
709** if such a lock exists and false otherwise.
710**
711** The xFileControl() method is a generic interface that allows custom
712** VFS implementations to directly control an open file using the
713** [sqlite3_file_control()] interface. The second "op" argument is an
714** integer opcode. The third argument is a generic pointer intended to
715** point to a structure that may contain arguments or space in which to
716** write return values. Potential uses for xFileControl() might be
717** functions to enable blocking locks with timeouts, to change the
718** locking strategy (for example to use dot-file locks), to inquire
719** about the status of a lock, or to break stale locks. The SQLite
720** core reserves all opcodes less than 100 for its own use.
721** A [file control opcodes | list of opcodes] less than 100 is available.
722** Applications that define a custom xFileControl method should use opcodes
723** greater than 100 to avoid conflicts. VFS implementations should
724** return [SQLITE_NOTFOUND] for file control opcodes that they do not
725** recognize.
726**
727** The xSectorSize() method returns the sector size of the
728** device that underlies the file. The sector size is the
729** minimum write that can be performed without disturbing
730** other bytes in the file. The xDeviceCharacteristics()
731** method returns a bit vector describing behaviors of the
732** underlying device:
733**
734** <ul>
735** <li> [SQLITE_IOCAP_ATOMIC]
736** <li> [SQLITE_IOCAP_ATOMIC512]
737** <li> [SQLITE_IOCAP_ATOMIC1K]
738** <li> [SQLITE_IOCAP_ATOMIC2K]
739** <li> [SQLITE_IOCAP_ATOMIC4K]
740** <li> [SQLITE_IOCAP_ATOMIC8K]
741** <li> [SQLITE_IOCAP_ATOMIC16K]
742** <li> [SQLITE_IOCAP_ATOMIC32K]
743** <li> [SQLITE_IOCAP_ATOMIC64K]
744** <li> [SQLITE_IOCAP_SAFE_APPEND]
745** <li> [SQLITE_IOCAP_SEQUENTIAL]
746** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
747** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
748** <li> [SQLITE_IOCAP_IMMUTABLE]
749** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
750** </ul>
751**
752** The SQLITE_IOCAP_ATOMIC property means that all writes of
753** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
754** mean that writes of blocks that are nnn bytes in size and
755** are aligned to an address which is an integer multiple of
756** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
757** that when data is appended to a file, the data is appended
758** first then the size of the file is extended, never the other
759** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
760** information is written to disk in the same order as calls
761** to xWrite().
762**
763** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
764** in the unread portions of the buffer with zeros. A VFS that
765** fails to zero-fill short reads might seem to work. However,
766** failure to zero-fill short reads will eventually lead to
767** database corruption.
768*/
769typedef struct sqlite3_io_methods sqlite3_io_methods;
770struct sqlite3_io_methods {
771 int iVersion;
772 int (*xClose)(sqlite3_file*);
773 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
774 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
775 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
776 int (*xSync)(sqlite3_file*, int flags);
777 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
778 int (*xLock)(sqlite3_file*, int);
779 int (*xUnlock)(sqlite3_file*, int);
780 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
781 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
782 int (*xSectorSize)(sqlite3_file*);
783 int (*xDeviceCharacteristics)(sqlite3_file*);
784 /* Methods above are valid for version 1 */
785 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
786 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
787 void (*xShmBarrier)(sqlite3_file*);
788 int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
789 /* Methods above are valid for version 2 */
790 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
791 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
792 /* Methods above are valid for version 3 */
793 /* Additional methods may be added in future releases */
794};
795
796/*
797** CAPI3REF: Standard File Control Opcodes
798** KEYWORDS: {file control opcodes} {file control opcode}
799**
800** These integer constants are opcodes for the xFileControl method
801** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
802** interface.
803**
804** <ul>
805** <li>[[SQLITE_FCNTL_LOCKSTATE]]
806** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
807** opcode causes the xFileControl method to write the current state of
808** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
809** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
810** into an integer that the pArg argument points to. This capability
811** is used during testing and is only available when the SQLITE_TEST
812** compile-time option is used.
813**
814** <li>[[SQLITE_FCNTL_SIZE_HINT]]
815** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
816** layer a hint of how large the database file will grow to be during the
817** current transaction. This hint is not guaranteed to be accurate but it
818** is often close. The underlying VFS might choose to preallocate database
819** file space based on this hint in order to help writes to the database
820** file run faster.
821**
822** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
823** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
824** extends and truncates the database file in chunks of a size specified
825** by the user. The fourth argument to [sqlite3_file_control()] should
826** point to an integer (type int) containing the new chunk-size to use
827** for the nominated database. Allocating database file space in large
828** chunks (say 1MB at a time), may reduce file-system fragmentation and
829** improve performance on some systems.
830**
831** <li>[[SQLITE_FCNTL_FILE_POINTER]]
832** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
833** to the [sqlite3_file] object associated with a particular database
834** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER].
835**
836** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
837** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
838** to the [sqlite3_file] object associated with the journal file (either
839** the [rollback journal] or the [write-ahead log]) for a particular database
840** connection. See also [SQLITE_FCNTL_FILE_POINTER].
841**
842** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
843** No longer in use.
844**
845** <li>[[SQLITE_FCNTL_SYNC]]
846** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
847** sent to the VFS immediately before the xSync method is invoked on a
848** database file descriptor. Or, if the xSync method is not invoked
849** because the user has configured SQLite with
850** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
851** of the xSync method. In most cases, the pointer argument passed with
852** this file-control is NULL. However, if the database file is being synced
853** as part of a multi-database commit, the argument points to a nul-terminated
854** string containing the transactions master-journal file name. VFSes that
855** do not need this signal should silently ignore this opcode. Applications
856** should not call [sqlite3_file_control()] with this opcode as doing so may
857** disrupt the operation of the specialized VFSes that do require it.
858**
859** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
860** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
861** and sent to the VFS after a transaction has been committed immediately
862** but before the database is unlocked. VFSes that do not need this signal
863** should silently ignore this opcode. Applications should not call
864** [sqlite3_file_control()] with this opcode as doing so may disrupt the
865** operation of the specialized VFSes that do require it.
866**
867** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
868** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
869** retry counts and intervals for certain disk I/O operations for the
870** windows [VFS] in order to provide robustness in the presence of
871** anti-virus programs. By default, the windows VFS will retry file read,
872** file write, and file delete operations up to 10 times, with a delay
873** of 25 milliseconds before the first retry and with the delay increasing
874** by an additional 25 milliseconds with each subsequent retry. This
875** opcode allows these two values (10 retries and 25 milliseconds of delay)
876** to be adjusted. The values are changed for all database connections
877** within the same process. The argument is a pointer to an array of two
878** integers where the first integer is the new retry count and the second
879** integer is the delay. If either integer is negative, then the setting
880** is not changed but instead the prior value of that setting is written
881** into the array entry, allowing the current retry settings to be
882** interrogated. The zDbName parameter is ignored.
883**
884** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
885** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
886** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
887** write ahead log and shared memory files used for transaction control
888** are automatically deleted when the latest connection to the database
889** closes. Setting persistent WAL mode causes those files to persist after
890** close. Persisting the files is useful when other processes that do not
891** have write permission on the directory containing the database file want
892** to read the database file, as the WAL and shared memory files must exist
893** in order for the database to be readable. The fourth parameter to
894** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
895** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
896** WAL mode. If the integer is -1, then it is overwritten with the current
897** WAL persistence setting.
898**
899** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
900** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
901** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
902** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
903** xDeviceCharacteristics methods. The fourth parameter to
904** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
905** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
906** mode. If the integer is -1, then it is overwritten with the current
907** zero-damage mode setting.
908**
909** <li>[[SQLITE_FCNTL_OVERWRITE]]
910** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
911** a write transaction to indicate that, unless it is rolled back for some
912** reason, the entire database file will be overwritten by the current
913** transaction. This is used by VACUUM operations.
914**
915** <li>[[SQLITE_FCNTL_VFSNAME]]
916** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
917** all [VFSes] in the VFS stack. The names are of all VFS shims and the
918** final bottom-level VFS are written into memory obtained from
919** [sqlite3_malloc()] and the result is stored in the char* variable
920** that the fourth parameter of [sqlite3_file_control()] points to.
921** The caller is responsible for freeing the memory when done. As with
922** all file-control actions, there is no guarantee that this will actually
923** do anything. Callers should initialize the char* variable to a NULL
924** pointer in case this file-control is not implemented. This file-control
925** is intended for diagnostic use only.
926**
927** <li>[[SQLITE_FCNTL_VFS_POINTER]]
928** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
929** [VFSes] currently in use. ^(The argument X in
930** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
931** of type "[sqlite3_vfs] **". This opcodes will set *X
932** to a pointer to the top-level VFS.)^
933** ^When there are multiple VFS shims in the stack, this opcode finds the
934** upper-most shim only.
935**
936** <li>[[SQLITE_FCNTL_PRAGMA]]
937** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
938** file control is sent to the open [sqlite3_file] object corresponding
939** to the database file to which the pragma statement refers. ^The argument
940** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
941** pointers to strings (char**) in which the second element of the array
942** is the name of the pragma and the third element is the argument to the
943** pragma or NULL if the pragma has no argument. ^The handler for an
944** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
945** of the char** argument point to a string obtained from [sqlite3_mprintf()]
946** or the equivalent and that string will become the result of the pragma or
947** the error message if the pragma fails. ^If the
948** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
949** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
950** file control returns [SQLITE_OK], then the parser assumes that the
951** VFS has handled the PRAGMA itself and the parser generates a no-op
952** prepared statement if result string is NULL, or that returns a copy
953** of the result string if the string is non-NULL.
954** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
955** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
956** that the VFS encountered an error while handling the [PRAGMA] and the
957** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
958** file control occurs at the beginning of pragma statement analysis and so
959** it is able to override built-in [PRAGMA] statements.
960**
961** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
962** ^The [SQLITE_FCNTL_BUSYHANDLER]
963** file-control may be invoked by SQLite on the database file handle
964** shortly after it is opened in order to provide a custom VFS with access
965** to the connections busy-handler callback. The argument is of type (void **)
966** - an array of two (void *) values. The first (void *) actually points
967** to a function of type (int (*)(void *)). In order to invoke the connections
968** busy-handler, this function should be invoked with the second (void *) in
969** the array as the only argument. If it returns non-zero, then the operation
970** should be retried. If it returns zero, the custom VFS should abandon the
971** current operation.
972**
973** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
974** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
975** to have SQLite generate a
976** temporary filename using the same algorithm that is followed to generate
977** temporary filenames for TEMP tables and other internal uses. The
978** argument should be a char** which will be filled with the filename
979** written into memory obtained from [sqlite3_malloc()]. The caller should
980** invoke [sqlite3_free()] on the result to avoid a memory leak.
981**
982** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
983** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
984** maximum number of bytes that will be used for memory-mapped I/O.
985** The argument is a pointer to a value of type sqlite3_int64 that
986** is an advisory maximum number of bytes in the file to memory map. The
987** pointer is overwritten with the old value. The limit is not changed if
988** the value originally pointed to is negative, and so the current limit
989** can be queried by passing in a pointer to a negative number. This
990** file-control is used internally to implement [PRAGMA mmap_size].
991**
992** <li>[[SQLITE_FCNTL_TRACE]]
993** The [SQLITE_FCNTL_TRACE] file control provides advisory information
994** to the VFS about what the higher layers of the SQLite stack are doing.
995** This file control is used by some VFS activity tracing [shims].
996** The argument is a zero-terminated string. Higher layers in the
997** SQLite stack may generate instances of this file control if
998** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
999**
1000** <li>[[SQLITE_FCNTL_HAS_MOVED]]
1001** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
1002** pointer to an integer and it writes a boolean into that integer depending
1003** on whether or not the file has been renamed, moved, or deleted since it
1004** was first opened.
1005**
1006** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
1007** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
1008** underlying native file handle associated with a file handle. This file
1009** control interprets its argument as a pointer to a native file handle and
1010** writes the resulting value there.
1011**
1012** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
1013** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This
1014** opcode causes the xFileControl method to swap the file handle with the one
1015** pointed to by the pArg argument. This capability is used during testing
1016** and only needs to be supported when SQLITE_TEST is defined.
1017**
1018** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
1019** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
1020** be advantageous to block on the next WAL lock if the lock is not immediately
1021** available. The WAL subsystem issues this signal during rare
1022** circumstances in order to fix a problem with priority inversion.
1023** Applications should <em>not</em> use this file-control.
1024**
1025** <li>[[SQLITE_FCNTL_ZIPVFS]]
1026** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
1027** VFS should return SQLITE_NOTFOUND for this opcode.
1028**
1029** <li>[[SQLITE_FCNTL_RBU]]
1030** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
1031** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for
1032** this opcode.
1033**
1034** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
1035** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
1036** the file descriptor is placed in "batch write mode", which
1037** means all subsequent write operations will be deferred and done
1038** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems
1039** that do not support batch atomic writes will return SQLITE_NOTFOUND.
1040** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
1041** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
1042** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
1043** no VFS interface calls on the same [sqlite3_file] file descriptor
1044** except for calls to the xWrite method and the xFileControl method
1045** with [SQLITE_FCNTL_SIZE_HINT].
1046**
1047** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
1048** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
1049** operations since the previous successful call to
1050** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
1051** This file control returns [SQLITE_OK] if and only if the writes were
1052** all performed successfully and have been committed to persistent storage.
1053** ^Regardless of whether or not it is successful, this file control takes
1054** the file descriptor out of batch write mode so that all subsequent
1055** write operations are independent.
1056** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
1057** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1058**
1059** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
1060** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
1061** operations since the previous successful call to
1062** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
1063** ^This file control takes the file descriptor out of batch write mode
1064** so that all subsequent write operations are independent.
1065** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
1066** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1067** </ul>
1068*/
1069#define SQLITE_FCNTL_LOCKSTATE 1
1070#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2
1071#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3
1072#define SQLITE_FCNTL_LAST_ERRNO 4
1073#define SQLITE_FCNTL_SIZE_HINT 5
1074#define SQLITE_FCNTL_CHUNK_SIZE 6
1075#define SQLITE_FCNTL_FILE_POINTER 7
1076#define SQLITE_FCNTL_SYNC_OMITTED 8
1077#define SQLITE_FCNTL_WIN32_AV_RETRY 9
1078#define SQLITE_FCNTL_PERSIST_WAL 10
1079#define SQLITE_FCNTL_OVERWRITE 11
1080#define SQLITE_FCNTL_VFSNAME 12
1081#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
1082#define SQLITE_FCNTL_PRAGMA 14
1083#define SQLITE_FCNTL_BUSYHANDLER 15
1084#define SQLITE_FCNTL_TEMPFILENAME 16
1085#define SQLITE_FCNTL_MMAP_SIZE 18
1086#define SQLITE_FCNTL_TRACE 19
1087#define SQLITE_FCNTL_HAS_MOVED 20
1088#define SQLITE_FCNTL_SYNC 21
1089#define SQLITE_FCNTL_COMMIT_PHASETWO 22
1090#define SQLITE_FCNTL_WIN32_SET_HANDLE 23
1091#define SQLITE_FCNTL_WAL_BLOCK 24
1092#define SQLITE_FCNTL_ZIPVFS 25
1093#define SQLITE_FCNTL_RBU 26
1094#define SQLITE_FCNTL_VFS_POINTER 27
1095#define SQLITE_FCNTL_JOURNAL_POINTER 28
1096#define SQLITE_FCNTL_WIN32_GET_HANDLE 29
1097#define SQLITE_FCNTL_PDB 30
1098#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31
1099#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32
1100#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33
1101
1102/* deprecated names */
1103#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE
1104#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE
1105#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO
1106
1107
1108/*
1109** CAPI3REF: Mutex Handle
1110**
1111** The mutex module within SQLite defines [sqlite3_mutex] to be an
1112** abstract type for a mutex object. The SQLite core never looks
1113** at the internal representation of an [sqlite3_mutex]. It only
1114** deals with pointers to the [sqlite3_mutex] object.
1115**
1116** Mutexes are created using [sqlite3_mutex_alloc()].
1117*/
1118typedef struct sqlite3_mutex sqlite3_mutex;
1119
1120/*
1121** CAPI3REF: Loadable Extension Thunk
1122**
1123** A pointer to the opaque sqlite3_api_routines structure is passed as
1124** the third parameter to entry points of [loadable extensions]. This
1125** structure must be typedefed in order to work around compiler warnings
1126** on some platforms.
1127*/
1128typedef struct sqlite3_api_routines sqlite3_api_routines;
1129
1130/*
1131** CAPI3REF: OS Interface Object
1132**
1133** An instance of the sqlite3_vfs object defines the interface between
1134** the SQLite core and the underlying operating system. The "vfs"
1135** in the name of the object stands for "virtual file system". See
1136** the [VFS | VFS documentation] for further information.
1137**
1138** The VFS interface is sometimes extended by adding new methods onto
1139** the end. Each time such an extension occurs, the iVersion field
1140** is incremented. The iVersion value started out as 1 in
1141** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
1142** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
1143** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields
1144** may be appended to the sqlite3_vfs object and the iVersion value
1145** may increase again in future versions of SQLite.
1146** Note that the structure
1147** of the sqlite3_vfs object changes in the transition from
1148** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
1149** and yet the iVersion field was not modified.
1150**
1151** The szOsFile field is the size of the subclassed [sqlite3_file]
1152** structure used by this VFS. mxPathname is the maximum length of
1153** a pathname in this VFS.
1154**
1155** Registered sqlite3_vfs objects are kept on a linked list formed by
1156** the pNext pointer. The [sqlite3_vfs_register()]
1157** and [sqlite3_vfs_unregister()] interfaces manage this list
1158** in a thread-safe way. The [sqlite3_vfs_find()] interface
1159** searches the list. Neither the application code nor the VFS
1160** implementation should use the pNext pointer.
1161**
1162** The pNext field is the only field in the sqlite3_vfs
1163** structure that SQLite will ever modify. SQLite will only access
1164** or modify this field while holding a particular static mutex.
1165** The application should never modify anything within the sqlite3_vfs
1166** object once the object has been registered.
1167**
1168** The zName field holds the name of the VFS module. The name must
1169** be unique across all VFS modules.
1170**
1171** [[sqlite3_vfs.xOpen]]
1172** ^SQLite guarantees that the zFilename parameter to xOpen
1173** is either a NULL pointer or string obtained
1174** from xFullPathname() with an optional suffix added.
1175** ^If a suffix is added to the zFilename parameter, it will
1176** consist of a single "-" character followed by no more than
1177** 11 alphanumeric and/or "-" characters.
1178** ^SQLite further guarantees that
1179** the string will be valid and unchanged until xClose() is
1180** called. Because of the previous sentence,
1181** the [sqlite3_file] can safely store a pointer to the
1182** filename if it needs to remember the filename for some reason.
1183** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1184** must invent its own temporary name for the file. ^Whenever the
1185** xFilename parameter is NULL it will also be the case that the
1186** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1187**
1188** The flags argument to xOpen() includes all bits set in
1189** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
1190** or [sqlite3_open16()] is used, then flags includes at least
1191** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1192** If xOpen() opens a file read-only then it sets *pOutFlags to
1193** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
1194**
1195** ^(SQLite will also add one of the following flags to the xOpen()
1196** call, depending on the object being opened:
1197**
1198** <ul>
1199** <li> [SQLITE_OPEN_MAIN_DB]
1200** <li> [SQLITE_OPEN_MAIN_JOURNAL]
1201** <li> [SQLITE_OPEN_TEMP_DB]
1202** <li> [SQLITE_OPEN_TEMP_JOURNAL]
1203** <li> [SQLITE_OPEN_TRANSIENT_DB]
1204** <li> [SQLITE_OPEN_SUBJOURNAL]
1205** <li> [SQLITE_OPEN_MASTER_JOURNAL]
1206** <li> [SQLITE_OPEN_WAL]
1207** </ul>)^
1208**
1209** The file I/O implementation can use the object type flags to
1210** change the way it deals with files. For example, an application
1211** that does not care about crash recovery or rollback might make
1212** the open of a journal file a no-op. Writes to this journal would
1213** also be no-ops, and any attempt to read the journal would return
1214** SQLITE_IOERR. Or the implementation might recognize that a database
1215** file will be doing page-aligned sector reads and writes in a random
1216** order and set up its I/O subsystem accordingly.
1217**
1218** SQLite might also add one of the following flags to the xOpen method:
1219**
1220** <ul>
1221** <li> [SQLITE_OPEN_DELETEONCLOSE]
1222** <li> [SQLITE_OPEN_EXCLUSIVE]
1223** </ul>
1224**
1225** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1226** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1227** will be set for TEMP databases and their journals, transient
1228** databases, and subjournals.
1229**
1230** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1231** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1232** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1233** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1234** SQLITE_OPEN_CREATE, is used to indicate that file should always
1235** be created, and that it is an error if it already exists.
1236** It is <i>not</i> used to indicate the file should be opened
1237** for exclusive access.
1238**
1239** ^At least szOsFile bytes of memory are allocated by SQLite
1240** to hold the [sqlite3_file] structure passed as the third
1241** argument to xOpen. The xOpen method does not have to
1242** allocate the structure; it should just fill it in. Note that
1243** the xOpen method must set the sqlite3_file.pMethods to either
1244** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1245** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1246** element will be valid after xOpen returns regardless of the success
1247** or failure of the xOpen call.
1248**
1249** [[sqlite3_vfs.xAccess]]
1250** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1251** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1252** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1253** to test whether a file is at least readable. The file can be a
1254** directory.
1255**
1256** ^SQLite will always allocate at least mxPathname+1 bytes for the
1257** output buffer xFullPathname. The exact size of the output buffer
1258** is also passed as a parameter to both methods. If the output buffer
1259** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1260** handled as a fatal error by SQLite, vfs implementations should endeavor
1261** to prevent this by setting mxPathname to a sufficiently large value.
1262**
1263** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1264** interfaces are not strictly a part of the filesystem, but they are
1265** included in the VFS structure for completeness.
1266** The xRandomness() function attempts to return nBytes bytes
1267** of good-quality randomness into zOut. The return value is
1268** the actual number of bytes of randomness obtained.
1269** The xSleep() method causes the calling thread to sleep for at
1270** least the number of microseconds given. ^The xCurrentTime()
1271** method returns a Julian Day Number for the current date and time as
1272** a floating point value.
1273** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1274** Day Number multiplied by 86400000 (the number of milliseconds in
1275** a 24-hour day).
1276** ^SQLite will use the xCurrentTimeInt64() method to get the current
1277** date and time if that method is available (if iVersion is 2 or
1278** greater and the function pointer is not NULL) and will fall back
1279** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1280**
1281** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1282** are not used by the SQLite core. These optional interfaces are provided
1283** by some VFSes to facilitate testing of the VFS code. By overriding
1284** system calls with functions under its control, a test program can
1285** simulate faults and error conditions that would otherwise be difficult
1286** or impossible to induce. The set of system calls that can be overridden
1287** varies from one VFS to another, and from one version of the same VFS to the
1288** next. Applications that use these interfaces must be prepared for any
1289** or all of these interfaces to be NULL or for their behavior to change
1290** from one release to the next. Applications must not attempt to access
1291** any of these methods if the iVersion of the VFS is less than 3.
1292*/
1293typedef struct sqlite3_vfs sqlite3_vfs;
1294typedef void (*sqlite3_syscall_ptr)(void);
1295struct sqlite3_vfs {
1296 int iVersion; /* Structure version number (currently 3) */
1297 int szOsFile; /* Size of subclassed sqlite3_file */
1298 int mxPathname; /* Maximum file pathname length */
1299 sqlite3_vfs *pNext; /* Next registered VFS */
1300 const char *zName; /* Name of this virtual file system */
1301 void *pAppData; /* Pointer to application-specific data */
1302 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1303 int flags, int *pOutFlags);
1304 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1305 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1306 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1307 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1308 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1309 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1310 void (*xDlClose)(sqlite3_vfs*, void*);
1311 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1312 int (*xSleep)(sqlite3_vfs*, int microseconds);
1313 int (*xCurrentTime)(sqlite3_vfs*, double*);
1314 int (*xGetLastError)(sqlite3_vfs*, int, char *);
1315 /*
1316 ** The methods above are in version 1 of the sqlite_vfs object
1317 ** definition. Those that follow are added in version 2 or later
1318 */
1319 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1320 /*
1321 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1322 ** Those below are for version 3 and greater.
1323 */
1324 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1325 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1326 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1327 /*
1328 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1329 ** New fields may be appended in future versions. The iVersion
1330 ** value will increment whenever this happens.
1331 */
1332};
1333
1334/*
1335** CAPI3REF: Flags for the xAccess VFS method
1336**
1337** These integer constants can be used as the third parameter to
1338** the xAccess method of an [sqlite3_vfs] object. They determine
1339** what kind of permissions the xAccess method is looking for.
1340** With SQLITE_ACCESS_EXISTS, the xAccess method
1341** simply checks whether the file exists.
1342** With SQLITE_ACCESS_READWRITE, the xAccess method
1343** checks whether the named directory is both readable and writable
1344** (in other words, if files can be added, removed, and renamed within
1345** the directory).
1346** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1347** [temp_store_directory pragma], though this could change in a future
1348** release of SQLite.
1349** With SQLITE_ACCESS_READ, the xAccess method
1350** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1351** currently unused, though it might be used in a future release of
1352** SQLite.
1353*/
1354#define SQLITE_ACCESS_EXISTS 0
1355#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1356#define SQLITE_ACCESS_READ 2 /* Unused */
1357
1358/*
1359** CAPI3REF: Flags for the xShmLock VFS method
1360**
1361** These integer constants define the various locking operations
1362** allowed by the xShmLock method of [sqlite3_io_methods]. The
1363** following are the only legal combinations of flags to the
1364** xShmLock method:
1365**
1366** <ul>
1367** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1368** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1369** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1370** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1371** </ul>
1372**
1373** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1374** was given on the corresponding lock.
1375**
1376** The xShmLock method can transition between unlocked and SHARED or
1377** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1378** and EXCLUSIVE.
1379*/
1380#define SQLITE_SHM_UNLOCK 1
1381#define SQLITE_SHM_LOCK 2
1382#define SQLITE_SHM_SHARED 4
1383#define SQLITE_SHM_EXCLUSIVE 8
1384
1385/*
1386** CAPI3REF: Maximum xShmLock index
1387**
1388** The xShmLock method on [sqlite3_io_methods] may use values
1389** between 0 and this upper bound as its "offset" argument.
1390** The SQLite core will never attempt to acquire or release a
1391** lock outside of this range
1392*/
1393#define SQLITE_SHM_NLOCK 8
1394
1395
1396/*
1397** CAPI3REF: Initialize The SQLite Library
1398**
1399** ^The sqlite3_initialize() routine initializes the
1400** SQLite library. ^The sqlite3_shutdown() routine
1401** deallocates any resources that were allocated by sqlite3_initialize().
1402** These routines are designed to aid in process initialization and
1403** shutdown on embedded systems. Workstation applications using
1404** SQLite normally do not need to invoke either of these routines.
1405**
1406** A call to sqlite3_initialize() is an "effective" call if it is
1407** the first time sqlite3_initialize() is invoked during the lifetime of
1408** the process, or if it is the first time sqlite3_initialize() is invoked
1409** following a call to sqlite3_shutdown(). ^(Only an effective call
1410** of sqlite3_initialize() does any initialization. All other calls
1411** are harmless no-ops.)^
1412**
1413** A call to sqlite3_shutdown() is an "effective" call if it is the first
1414** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1415** an effective call to sqlite3_shutdown() does any deinitialization.
1416** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1417**
1418** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1419** is not. The sqlite3_shutdown() interface must only be called from a
1420** single thread. All open [database connections] must be closed and all
1421** other SQLite resources must be deallocated prior to invoking
1422** sqlite3_shutdown().
1423**
1424** Among other things, ^sqlite3_initialize() will invoke
1425** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1426** will invoke sqlite3_os_end().
1427**
1428** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1429** ^If for some reason, sqlite3_initialize() is unable to initialize
1430** the library (perhaps it is unable to allocate a needed resource such
1431** as a mutex) it returns an [error code] other than [SQLITE_OK].
1432**
1433** ^The sqlite3_initialize() routine is called internally by many other
1434** SQLite interfaces so that an application usually does not need to
1435** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1436** calls sqlite3_initialize() so the SQLite library will be automatically
1437** initialized when [sqlite3_open()] is called if it has not be initialized
1438** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1439** compile-time option, then the automatic calls to sqlite3_initialize()
1440** are omitted and the application must call sqlite3_initialize() directly
1441** prior to using any other SQLite interface. For maximum portability,
1442** it is recommended that applications always invoke sqlite3_initialize()
1443** directly prior to using any other SQLite interface. Future releases
1444** of SQLite may require this. In other words, the behavior exhibited
1445** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1446** default behavior in some future release of SQLite.
1447**
1448** The sqlite3_os_init() routine does operating-system specific
1449** initialization of the SQLite library. The sqlite3_os_end()
1450** routine undoes the effect of sqlite3_os_init(). Typical tasks
1451** performed by these routines include allocation or deallocation
1452** of static resources, initialization of global variables,
1453** setting up a default [sqlite3_vfs] module, or setting up
1454** a default configuration using [sqlite3_config()].
1455**
1456** The application should never invoke either sqlite3_os_init()
1457** or sqlite3_os_end() directly. The application should only invoke
1458** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1459** interface is called automatically by sqlite3_initialize() and
1460** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1461** implementations for sqlite3_os_init() and sqlite3_os_end()
1462** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1463** When [custom builds | built for other platforms]
1464** (using the [SQLITE_OS_OTHER=1] compile-time
1465** option) the application must supply a suitable implementation for
1466** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1467** implementation of sqlite3_os_init() or sqlite3_os_end()
1468** must return [SQLITE_OK] on success and some other [error code] upon
1469** failure.
1470*/
1471SQLITE_API int sqlite3_initialize(void);
1472SQLITE_API int sqlite3_shutdown(void);
1473SQLITE_API int sqlite3_os_init(void);
1474SQLITE_API int sqlite3_os_end(void);
1475
1476/*
1477** CAPI3REF: Configuring The SQLite Library
1478**
1479** The sqlite3_config() interface is used to make global configuration
1480** changes to SQLite in order to tune SQLite to the specific needs of
1481** the application. The default configuration is recommended for most
1482** applications and so this routine is usually not necessary. It is
1483** provided to support rare applications with unusual needs.
1484**
1485** <b>The sqlite3_config() interface is not threadsafe. The application
1486** must ensure that no other SQLite interfaces are invoked by other
1487** threads while sqlite3_config() is running.</b>
1488**
1489** The sqlite3_config() interface
1490** may only be invoked prior to library initialization using
1491** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1492** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1493** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1494** Note, however, that ^sqlite3_config() can be called as part of the
1495** implementation of an application-defined [sqlite3_os_init()].
1496**
1497** The first argument to sqlite3_config() is an integer
1498** [configuration option] that determines
1499** what property of SQLite is to be configured. Subsequent arguments
1500** vary depending on the [configuration option]
1501** in the first argument.
1502**
1503** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1504** ^If the option is unknown or SQLite is unable to set the option
1505** then this routine returns a non-zero [error code].
1506*/
1507SQLITE_API int sqlite3_config(int, ...);
1508
1509/*
1510** CAPI3REF: Configure database connections
1511** METHOD: sqlite3
1512**
1513** The sqlite3_db_config() interface is used to make configuration
1514** changes to a [database connection]. The interface is similar to
1515** [sqlite3_config()] except that the changes apply to a single
1516** [database connection] (specified in the first argument).
1517**
1518** The second argument to sqlite3_db_config(D,V,...) is the
1519** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1520** that indicates what aspect of the [database connection] is being configured.
1521** Subsequent arguments vary depending on the configuration verb.
1522**
1523** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1524** the call is considered successful.
1525*/
1526SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1527
1528/*
1529** CAPI3REF: Memory Allocation Routines
1530**
1531** An instance of this object defines the interface between SQLite
1532** and low-level memory allocation routines.
1533**
1534** This object is used in only one place in the SQLite interface.
1535** A pointer to an instance of this object is the argument to
1536** [sqlite3_config()] when the configuration option is
1537** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1538** By creating an instance of this object
1539** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1540** during configuration, an application can specify an alternative
1541** memory allocation subsystem for SQLite to use for all of its
1542** dynamic memory needs.
1543**
1544** Note that SQLite comes with several [built-in memory allocators]
1545** that are perfectly adequate for the overwhelming majority of applications
1546** and that this object is only useful to a tiny minority of applications
1547** with specialized memory allocation requirements. This object is
1548** also used during testing of SQLite in order to specify an alternative
1549** memory allocator that simulates memory out-of-memory conditions in
1550** order to verify that SQLite recovers gracefully from such
1551** conditions.
1552**
1553** The xMalloc, xRealloc, and xFree methods must work like the
1554** malloc(), realloc() and free() functions from the standard C library.
1555** ^SQLite guarantees that the second argument to
1556** xRealloc is always a value returned by a prior call to xRoundup.
1557**
1558** xSize should return the allocated size of a memory allocation
1559** previously obtained from xMalloc or xRealloc. The allocated size
1560** is always at least as big as the requested size but may be larger.
1561**
1562** The xRoundup method returns what would be the allocated size of
1563** a memory allocation given a particular requested size. Most memory
1564** allocators round up memory allocations at least to the next multiple
1565** of 8. Some allocators round up to a larger multiple or to a power of 2.
1566** Every memory allocation request coming in through [sqlite3_malloc()]
1567** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1568** that causes the corresponding memory allocation to fail.
1569**
1570** The xInit method initializes the memory allocator. For example,
1571** it might allocate any require mutexes or initialize internal data
1572** structures. The xShutdown method is invoked (indirectly) by
1573** [sqlite3_shutdown()] and should deallocate any resources acquired
1574** by xInit. The pAppData pointer is used as the only parameter to
1575** xInit and xShutdown.
1576**
1577** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1578** the xInit method, so the xInit method need not be threadsafe. The
1579** xShutdown method is only called from [sqlite3_shutdown()] so it does
1580** not need to be threadsafe either. For all other methods, SQLite
1581** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1582** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1583** it is by default) and so the methods are automatically serialized.
1584** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1585** methods must be threadsafe or else make their own arrangements for
1586** serialization.
1587**
1588** SQLite will never invoke xInit() more than once without an intervening
1589** call to xShutdown().
1590*/
1591typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1592struct sqlite3_mem_methods {
1593 void *(*xMalloc)(int); /* Memory allocation function */
1594 void (*xFree)(void*); /* Free a prior allocation */
1595 void *(*xRealloc)(void*,int); /* Resize an allocation */
1596 int (*xSize)(void*); /* Return the size of an allocation */
1597 int (*xRoundup)(int); /* Round up request size to allocation size */
1598 int (*xInit)(void*); /* Initialize the memory allocator */
1599 void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1600 void *pAppData; /* Argument to xInit() and xShutdown() */
1601};
1602
1603/*
1604** CAPI3REF: Configuration Options
1605** KEYWORDS: {configuration option}
1606**
1607** These constants are the available integer configuration options that
1608** can be passed as the first argument to the [sqlite3_config()] interface.
1609**
1610** New configuration options may be added in future releases of SQLite.
1611** Existing configuration options might be discontinued. Applications
1612** should check the return code from [sqlite3_config()] to make sure that
1613** the call worked. The [sqlite3_config()] interface will return a
1614** non-zero [error code] if a discontinued or unsupported configuration option
1615** is invoked.
1616**
1617** <dl>
1618** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1619** <dd>There are no arguments to this option. ^This option sets the
1620** [threading mode] to Single-thread. In other words, it disables
1621** all mutexing and puts SQLite into a mode where it can only be used
1622** by a single thread. ^If SQLite is compiled with
1623** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1624** it is not possible to change the [threading mode] from its default
1625** value of Single-thread and so [sqlite3_config()] will return
1626** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1627** configuration option.</dd>
1628**
1629** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1630** <dd>There are no arguments to this option. ^This option sets the
1631** [threading mode] to Multi-thread. In other words, it disables
1632** mutexing on [database connection] and [prepared statement] objects.
1633** The application is responsible for serializing access to
1634** [database connections] and [prepared statements]. But other mutexes
1635** are enabled so that SQLite will be safe to use in a multi-threaded
1636** environment as long as no two threads attempt to use the same
1637** [database connection] at the same time. ^If SQLite is compiled with
1638** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1639** it is not possible to set the Multi-thread [threading mode] and
1640** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1641** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1642**
1643** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1644** <dd>There are no arguments to this option. ^This option sets the
1645** [threading mode] to Serialized. In other words, this option enables
1646** all mutexes including the recursive
1647** mutexes on [database connection] and [prepared statement] objects.
1648** In this mode (which is the default when SQLite is compiled with
1649** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1650** to [database connections] and [prepared statements] so that the
1651** application is free to use the same [database connection] or the
1652** same [prepared statement] in different threads at the same time.
1653** ^If SQLite is compiled with
1654** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1655** it is not possible to set the Serialized [threading mode] and
1656** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1657** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1658**
1659** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1660** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1661** a pointer to an instance of the [sqlite3_mem_methods] structure.
1662** The argument specifies
1663** alternative low-level memory allocation routines to be used in place of
1664** the memory allocation routines built into SQLite.)^ ^SQLite makes
1665** its own private copy of the content of the [sqlite3_mem_methods] structure
1666** before the [sqlite3_config()] call returns.</dd>
1667**
1668** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1669** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1670** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1671** The [sqlite3_mem_methods]
1672** structure is filled with the currently defined memory allocation routines.)^
1673** This option can be used to overload the default memory allocation
1674** routines with a wrapper that simulations memory allocation failure or
1675** tracks memory usage, for example. </dd>
1676**
1677** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
1678** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
1679** type int, interpreted as a boolean, which if true provides a hint to
1680** SQLite that it should avoid large memory allocations if possible.
1681** SQLite will run faster if it is free to make large memory allocations,
1682** but some application might prefer to run slower in exchange for
1683** guarantees about memory fragmentation that are possible if large
1684** allocations are avoided. This hint is normally off.
1685** </dd>
1686**
1687** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1688** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1689** interpreted as a boolean, which enables or disables the collection of
1690** memory allocation statistics. ^(When memory allocation statistics are
1691** disabled, the following SQLite interfaces become non-operational:
1692** <ul>
1693** <li> [sqlite3_memory_used()]
1694** <li> [sqlite3_memory_highwater()]
1695** <li> [sqlite3_soft_heap_limit64()]
1696** <li> [sqlite3_status64()]
1697** </ul>)^
1698** ^Memory allocation statistics are enabled by default unless SQLite is
1699** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1700** allocation statistics are disabled by default.
1701** </dd>
1702**
1703** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1704** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
1705** </dd>
1706**
1707** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1708** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
1709** that SQLite can use for the database page cache with the default page
1710** cache implementation.
1711** This configuration option is a no-op if an application-define page
1712** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
1713** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1714** 8-byte aligned memory (pMem), the size of each page cache line (sz),
1715** and the number of cache lines (N).
1716** The sz argument should be the size of the largest database page
1717** (a power of two between 512 and 65536) plus some extra bytes for each
1718** page header. ^The number of extra bytes needed by the page header
1719** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
1720** ^It is harmless, apart from the wasted memory,
1721** for the sz parameter to be larger than necessary. The pMem
1722** argument must be either a NULL pointer or a pointer to an 8-byte
1723** aligned block of memory of at least sz*N bytes, otherwise
1724** subsequent behavior is undefined.
1725** ^When pMem is not NULL, SQLite will strive to use the memory provided
1726** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
1727** a page cache line is larger than sz bytes or if all of the pMem buffer
1728** is exhausted.
1729** ^If pMem is NULL and N is non-zero, then each database connection
1730** does an initial bulk allocation for page cache memory
1731** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
1732** of -1024*N bytes if N is negative, . ^If additional
1733** page cache memory is needed beyond what is provided by the initial
1734** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
1735** additional cache line. </dd>
1736**
1737** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1738** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1739** that SQLite will use for all of its dynamic memory allocation needs
1740** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
1741** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1742** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1743** [SQLITE_ERROR] if invoked otherwise.
1744** ^There are three arguments to SQLITE_CONFIG_HEAP:
1745** An 8-byte aligned pointer to the memory,
1746** the number of bytes in the memory buffer, and the minimum allocation size.
1747** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1748** to using its default memory allocator (the system malloc() implementation),
1749** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1750** memory pointer is not NULL then the alternative memory
1751** allocator is engaged to handle all of SQLites memory allocation needs.
1752** The first pointer (the memory pointer) must be aligned to an 8-byte
1753** boundary or subsequent behavior of SQLite will be undefined.
1754** The minimum allocation size is capped at 2**12. Reasonable values
1755** for the minimum allocation size are 2**5 through 2**8.</dd>
1756**
1757** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1758** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1759** pointer to an instance of the [sqlite3_mutex_methods] structure.
1760** The argument specifies alternative low-level mutex routines to be used
1761** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of
1762** the content of the [sqlite3_mutex_methods] structure before the call to
1763** [sqlite3_config()] returns. ^If SQLite is compiled with
1764** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1765** the entire mutexing subsystem is omitted from the build and hence calls to
1766** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1767** return [SQLITE_ERROR].</dd>
1768**
1769** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1770** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1771** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The
1772** [sqlite3_mutex_methods]
1773** structure is filled with the currently defined mutex routines.)^
1774** This option can be used to overload the default mutex allocation
1775** routines with a wrapper used to track mutex usage for performance
1776** profiling or testing, for example. ^If SQLite is compiled with
1777** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1778** the entire mutexing subsystem is omitted from the build and hence calls to
1779** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1780** return [SQLITE_ERROR].</dd>
1781**
1782** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1783** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1784** the default size of lookaside memory on each [database connection].
1785** The first argument is the
1786** size of each lookaside buffer slot and the second is the number of
1787** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE
1788** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1789** option to [sqlite3_db_config()] can be used to change the lookaside
1790** configuration on individual connections.)^ </dd>
1791**
1792** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1793** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1794** a pointer to an [sqlite3_pcache_methods2] object. This object specifies
1795** the interface to a custom page cache implementation.)^
1796** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1797**
1798** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1799** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1800** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of
1801** the current page cache implementation into that object.)^ </dd>
1802**
1803** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1804** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1805** global [error log].
1806** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1807** function with a call signature of void(*)(void*,int,const char*),
1808** and a pointer to void. ^If the function pointer is not NULL, it is
1809** invoked by [sqlite3_log()] to process each logging event. ^If the
1810** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1811** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1812** passed through as the first parameter to the application-defined logger
1813** function whenever that function is invoked. ^The second parameter to
1814** the logger function is a copy of the first parameter to the corresponding
1815** [sqlite3_log()] call and is intended to be a [result code] or an
1816** [extended result code]. ^The third parameter passed to the logger is
1817** log message after formatting via [sqlite3_snprintf()].
1818** The SQLite logging interface is not reentrant; the logger function
1819** supplied by the application must not invoke any SQLite interface.
1820** In a multi-threaded application, the application-defined logger
1821** function must be threadsafe. </dd>
1822**
1823** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1824** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1825** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1826** then URI handling is globally disabled.)^ ^If URI handling is globally
1827** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1828** [sqlite3_open16()] or
1829** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1830** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1831** connection is opened. ^If it is globally disabled, filenames are
1832** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1833** database connection is opened. ^(By default, URI handling is globally
1834** disabled. The default value may be changed by compiling with the
1835** [SQLITE_USE_URI] symbol defined.)^
1836**
1837** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1838** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1839** argument which is interpreted as a boolean in order to enable or disable
1840** the use of covering indices for full table scans in the query optimizer.
1841** ^The default setting is determined
1842** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1843** if that compile-time option is omitted.
1844** The ability to disable the use of covering indices for full table scans
1845** is because some incorrectly coded legacy applications might malfunction
1846** when the optimization is enabled. Providing the ability to
1847** disable the optimization allows the older, buggy application code to work
1848** without change even with newer versions of SQLite.
1849**
1850** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1851** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1852** <dd> These options are obsolete and should not be used by new code.
1853** They are retained for backwards compatibility but are now no-ops.
1854** </dd>
1855**
1856** [[SQLITE_CONFIG_SQLLOG]]
1857** <dt>SQLITE_CONFIG_SQLLOG
1858** <dd>This option is only available if sqlite is compiled with the
1859** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1860** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1861** The second should be of type (void*). The callback is invoked by the library
1862** in three separate circumstances, identified by the value passed as the
1863** fourth parameter. If the fourth parameter is 0, then the database connection
1864** passed as the second argument has just been opened. The third argument
1865** points to a buffer containing the name of the main database file. If the
1866** fourth parameter is 1, then the SQL statement that the third parameter
1867** points to has just been executed. Or, if the fourth parameter is 2, then
1868** the connection being passed as the second parameter is being closed. The
1869** third parameter is passed NULL In this case. An example of using this
1870** configuration option can be seen in the "test_sqllog.c" source file in
1871** the canonical SQLite source tree.</dd>
1872**
1873** [[SQLITE_CONFIG_MMAP_SIZE]]
1874** <dt>SQLITE_CONFIG_MMAP_SIZE
1875** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1876** that are the default mmap size limit (the default setting for
1877** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1878** ^The default setting can be overridden by each database connection using
1879** either the [PRAGMA mmap_size] command, or by using the
1880** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size
1881** will be silently truncated if necessary so that it does not exceed the
1882** compile-time maximum mmap size set by the
1883** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1884** ^If either argument to this option is negative, then that argument is
1885** changed to its compile-time default.
1886**
1887** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
1888** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
1889** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
1890** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
1891** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1892** that specifies the maximum size of the created heap.
1893**
1894** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
1895** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
1896** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
1897** is a pointer to an integer and writes into that integer the number of extra
1898** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
1899** The amount of extra space required can change depending on the compiler,
1900** target platform, and SQLite version.
1901**
1902** [[SQLITE_CONFIG_PMASZ]]
1903** <dt>SQLITE_CONFIG_PMASZ
1904** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
1905** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
1906** sorter to that integer. The default minimum PMA Size is set by the
1907** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched
1908** to help with sort operations when multithreaded sorting
1909** is enabled (using the [PRAGMA threads] command) and the amount of content
1910** to be sorted exceeds the page size times the minimum of the
1911** [PRAGMA cache_size] setting and this value.
1912**
1913** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
1914** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
1915** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
1916** becomes the [statement journal] spill-to-disk threshold.
1917** [Statement journals] are held in memory until their size (in bytes)
1918** exceeds this threshold, at which point they are written to disk.
1919** Or if the threshold is -1, statement journals are always held
1920** exclusively in memory.
1921** Since many statement journals never become large, setting the spill
1922** threshold to a value such as 64KiB can greatly reduce the amount of
1923** I/O required to support statement rollback.
1924** The default value for this setting is controlled by the
1925** [SQLITE_STMTJRNL_SPILL] compile-time option.
1926** </dl>
1927*/
1928#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1929#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1930#define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1931#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1932#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1933#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */
1934#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1935#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1936#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1937#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1938#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1939/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1940#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1941#define SQLITE_CONFIG_PCACHE 14 /* no-op */
1942#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
1943#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
1944#define SQLITE_CONFIG_URI 17 /* int */
1945#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
1946#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
1947#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
1948#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
1949#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
1950#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
1951#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */
1952#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */
1953#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */
1954#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */
1955
1956/*
1957** CAPI3REF: Database Connection Configuration Options
1958**
1959** These constants are the available integer configuration options that
1960** can be passed as the second argument to the [sqlite3_db_config()] interface.
1961**
1962** New configuration options may be added in future releases of SQLite.
1963** Existing configuration options might be discontinued. Applications
1964** should check the return code from [sqlite3_db_config()] to make sure that
1965** the call worked. ^The [sqlite3_db_config()] interface will return a
1966** non-zero [error code] if a discontinued or unsupported configuration option
1967** is invoked.
1968**
1969** <dl>
1970** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1971** <dd> ^This option takes three additional arguments that determine the
1972** [lookaside memory allocator] configuration for the [database connection].
1973** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1974** pointer to a memory buffer to use for lookaside memory.
1975** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1976** may be NULL in which case SQLite will allocate the
1977** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1978** size of each lookaside buffer slot. ^The third argument is the number of
1979** slots. The size of the buffer in the first argument must be greater than
1980** or equal to the product of the second and third arguments. The buffer
1981** must be aligned to an 8-byte boundary. ^If the second argument to
1982** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1983** rounded down to the next smaller multiple of 8. ^(The lookaside memory
1984** configuration for a database connection can only be changed when that
1985** connection is not currently using lookaside memory, or in other words
1986** when the "current value" returned by
1987** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1988** Any attempt to change the lookaside memory configuration when lookaside
1989** memory is in use leaves the configuration unchanged and returns
1990** [SQLITE_BUSY].)^</dd>
1991**
1992** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1993** <dd> ^This option is used to enable or disable the enforcement of
1994** [foreign key constraints]. There should be two additional arguments.
1995** The first argument is an integer which is 0 to disable FK enforcement,
1996** positive to enable FK enforcement or negative to leave FK enforcement
1997** unchanged. The second parameter is a pointer to an integer into which
1998** is written 0 or 1 to indicate whether FK enforcement is off or on
1999** following this call. The second parameter may be a NULL pointer, in
2000** which case the FK enforcement setting is not reported back. </dd>
2001**
2002** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
2003** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
2004** There should be two additional arguments.
2005** The first argument is an integer which is 0 to disable triggers,
2006** positive to enable triggers or negative to leave the setting unchanged.
2007** The second parameter is a pointer to an integer into which
2008** is written 0 or 1 to indicate whether triggers are disabled or enabled
2009** following this call. The second parameter may be a NULL pointer, in
2010** which case the trigger setting is not reported back. </dd>
2011**
2012** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
2013** <dd> ^This option is used to enable or disable the two-argument
2014** version of the [fts3_tokenizer()] function which is part of the
2015** [FTS3] full-text search engine extension.
2016** There should be two additional arguments.
2017** The first argument is an integer which is 0 to disable fts3_tokenizer() or
2018** positive to enable fts3_tokenizer() or negative to leave the setting
2019** unchanged.
2020** The second parameter is a pointer to an integer into which
2021** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
2022** following this call. The second parameter may be a NULL pointer, in
2023** which case the new setting is not reported back. </dd>
2024**
2025** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
2026** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
2027** interface independently of the [load_extension()] SQL function.
2028** The [sqlite3_enable_load_extension()] API enables or disables both the
2029** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
2030** There should be two additional arguments.
2031** When the first argument to this interface is 1, then only the C-API is
2032** enabled and the SQL function remains disabled. If the first argument to
2033** this interface is 0, then both the C-API and the SQL function are disabled.
2034** If the first argument is -1, then no changes are made to state of either the
2035** C-API or the SQL function.
2036** The second parameter is a pointer to an integer into which
2037** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
2038** is disabled or enabled following this call. The second parameter may
2039** be a NULL pointer, in which case the new setting is not reported back.
2040** </dd>
2041**
2042** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
2043** <dd> ^This option is used to change the name of the "main" database
2044** schema. ^The sole argument is a pointer to a constant UTF8 string
2045** which will become the new schema name in place of "main". ^SQLite
2046** does not make a copy of the new main schema name string, so the application
2047** must ensure that the argument passed into this DBCONFIG option is unchanged
2048** until after the database connection closes.
2049** </dd>
2050**
2051** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
2052** <dd> Usually, when a database in wal mode is closed or detached from a
2053** database handle, SQLite checks if this will mean that there are now no
2054** connections at all to the database. If so, it performs a checkpoint
2055** operation before closing the connection. This option may be used to
2056** override this behaviour. The first parameter passed to this operation
2057** is an integer - non-zero to disable checkpoints-on-close, or zero (the
2058** default) to enable them. The second parameter is a pointer to an integer
2059** into which is written 0 or 1 to indicate whether checkpoints-on-close
2060** have been disabled - 0 if they are not disabled, 1 if they are.
2061** </dd>
2062** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
2063** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
2064** the [query planner stability guarantee] (QPSG). When the QPSG is active,
2065** a single SQL query statement will always use the same algorithm regardless
2066** of values of [bound parameters].)^ The QPSG disables some query optimizations
2067** that look at the values of bound parameters, which can make some queries
2068** slower. But the QPSG has the advantage of more predictable behavior. With
2069** the QPSG active, SQLite will always use the same query plan in the field as
2070** was used during testing in the lab.
2071** </dd>
2072** <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
2073** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
2074** include output for any operations performed by trigger programs. This
2075** option is used to set or clear (the default) a flag that governs this
2076** behavior. The first parameter passed to this operation is an integer -
2077** non-zero to enable output for trigger programs, or zero to disable it.
2078** The second parameter is a pointer to an integer into which is written
2079** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
2080** it is not disabled, 1 if it is.
2081** </dd>
2082** </dl>
2083*/
2084#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */
2085#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
2086#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
2087#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
2088#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
2089#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
2090#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */
2091#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */
2092#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */
2093#define SQLITE_DBCONFIG_MAX 1008 /* Largest DBCONFIG */
2094
2095/*
2096** CAPI3REF: Enable Or Disable Extended Result Codes
2097** METHOD: sqlite3
2098**
2099** ^The sqlite3_extended_result_codes() routine enables or disables the
2100** [extended result codes] feature of SQLite. ^The extended result
2101** codes are disabled by default for historical compatibility.
2102*/
2103SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
2104
2105/*
2106** CAPI3REF: Last Insert Rowid
2107** METHOD: sqlite3
2108**
2109** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
2110** has a unique 64-bit signed
2111** integer key called the [ROWID | "rowid"]. ^The rowid is always available
2112** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
2113** names are not also used by explicitly declared columns. ^If
2114** the table has a column of type [INTEGER PRIMARY KEY] then that column
2115** is another alias for the rowid.
2116**
2117** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
2118** the most recent successful [INSERT] into a rowid table or [virtual table]
2119** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
2120** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
2121** on the database connection D, then sqlite3_last_insert_rowid(D) returns
2122** zero.
2123**
2124** As well as being set automatically as rows are inserted into database
2125** tables, the value returned by this function may be set explicitly by
2126** [sqlite3_set_last_insert_rowid()]
2127**
2128** Some virtual table implementations may INSERT rows into rowid tables as
2129** part of committing a transaction (e.g. to flush data accumulated in memory
2130** to disk). In this case subsequent calls to this function return the rowid
2131** associated with these internal INSERT operations, which leads to
2132** unintuitive results. Virtual table implementations that do write to rowid
2133** tables in this way can avoid this problem by restoring the original
2134** rowid value using [sqlite3_set_last_insert_rowid()] before returning
2135** control to the user.
2136**
2137** ^(If an [INSERT] occurs within a trigger then this routine will
2138** return the [rowid] of the inserted row as long as the trigger is
2139** running. Once the trigger program ends, the value returned
2140** by this routine reverts to what it was before the trigger was fired.)^
2141**
2142** ^An [INSERT] that fails due to a constraint violation is not a
2143** successful [INSERT] and does not change the value returned by this
2144** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
2145** and INSERT OR ABORT make no changes to the return value of this
2146** routine when their insertion fails. ^(When INSERT OR REPLACE
2147** encounters a constraint violation, it does not fail. The
2148** INSERT continues to completion after deleting rows that caused
2149** the constraint problem so INSERT OR REPLACE will always change
2150** the return value of this interface.)^
2151**
2152** ^For the purposes of this routine, an [INSERT] is considered to
2153** be successful even if it is subsequently rolled back.
2154**
2155** This function is accessible to SQL statements via the
2156** [last_insert_rowid() SQL function].
2157**
2158** If a separate thread performs a new [INSERT] on the same
2159** database connection while the [sqlite3_last_insert_rowid()]
2160** function is running and thus changes the last insert [rowid],
2161** then the value returned by [sqlite3_last_insert_rowid()] is
2162** unpredictable and might not equal either the old or the new
2163** last insert [rowid].
2164*/
2165SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
2166
2167/*
2168** CAPI3REF: Set the Last Insert Rowid value.
2169** METHOD: sqlite3
2170**
2171** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
2172** set the value returned by calling sqlite3_last_insert_rowid(D) to R
2173** without inserting a row into the database.
2174*/
2175SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
2176
2177/*
2178** CAPI3REF: Count The Number Of Rows Modified
2179** METHOD: sqlite3
2180**
2181** ^This function returns the number of rows modified, inserted or
2182** deleted by the most recently completed INSERT, UPDATE or DELETE
2183** statement on the database connection specified by the only parameter.
2184** ^Executing any other type of SQL statement does not modify the value
2185** returned by this function.
2186**
2187** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
2188** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
2189** [foreign key actions] or [REPLACE] constraint resolution are not counted.
2190**
2191** Changes to a view that are intercepted by
2192** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
2193** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
2194** DELETE statement run on a view is always zero. Only changes made to real
2195** tables are counted.
2196**
2197** Things are more complicated if the sqlite3_changes() function is
2198** executed while a trigger program is running. This may happen if the
2199** program uses the [changes() SQL function], or if some other callback
2200** function invokes sqlite3_changes() directly. Essentially:
2201**
2202** <ul>
2203** <li> ^(Before entering a trigger program the value returned by
2204** sqlite3_changes() function is saved. After the trigger program
2205** has finished, the original value is restored.)^
2206**
2207** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
2208** statement sets the value returned by sqlite3_changes()
2209** upon completion as normal. Of course, this value will not include
2210** any changes performed by sub-triggers, as the sqlite3_changes()
2211** value will be saved and restored after each sub-trigger has run.)^
2212** </ul>
2213**
2214** ^This means that if the changes() SQL function (or similar) is used
2215** by the first INSERT, UPDATE or DELETE statement within a trigger, it
2216** returns the value as set when the calling statement began executing.
2217** ^If it is used by the second or subsequent such statement within a trigger
2218** program, the value returned reflects the number of rows modified by the
2219** previous INSERT, UPDATE or DELETE statement within the same trigger.
2220**
2221** See also the [sqlite3_total_changes()] interface, the
2222** [count_changes pragma], and the [changes() SQL function].
2223**
2224** If a separate thread makes changes on the same database connection
2225** while [sqlite3_changes()] is running then the value returned
2226** is unpredictable and not meaningful.
2227*/
2228SQLITE_API int sqlite3_changes(sqlite3*);
2229
2230/*
2231** CAPI3REF: Total Number Of Rows Modified
2232** METHOD: sqlite3
2233**
2234** ^This function returns the total number of rows inserted, modified or
2235** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2236** since the database connection was opened, including those executed as
2237** part of trigger programs. ^Executing any other type of SQL statement
2238** does not affect the value returned by sqlite3_total_changes().
2239**
2240** ^Changes made as part of [foreign key actions] are included in the
2241** count, but those made as part of REPLACE constraint resolution are
2242** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2243** are not counted.
2244**
2245** See also the [sqlite3_changes()] interface, the
2246** [count_changes pragma], and the [total_changes() SQL function].
2247**
2248** If a separate thread makes changes on the same database connection
2249** while [sqlite3_total_changes()] is running then the value
2250** returned is unpredictable and not meaningful.
2251*/
2252SQLITE_API int sqlite3_total_changes(sqlite3*);
2253
2254/*
2255** CAPI3REF: Interrupt A Long-Running Query
2256** METHOD: sqlite3
2257**
2258** ^This function causes any pending database operation to abort and
2259** return at its earliest opportunity. This routine is typically
2260** called in response to a user action such as pressing "Cancel"
2261** or Ctrl-C where the user wants a long query operation to halt
2262** immediately.
2263**
2264** ^It is safe to call this routine from a thread different from the
2265** thread that is currently running the database operation. But it
2266** is not safe to call this routine with a [database connection] that
2267** is closed or might close before sqlite3_interrupt() returns.
2268**
2269** ^If an SQL operation is very nearly finished at the time when
2270** sqlite3_interrupt() is called, then it might not have an opportunity
2271** to be interrupted and might continue to completion.
2272**
2273** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2274** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2275** that is inside an explicit transaction, then the entire transaction
2276** will be rolled back automatically.
2277**
2278** ^The sqlite3_interrupt(D) call is in effect until all currently running
2279** SQL statements on [database connection] D complete. ^Any new SQL statements
2280** that are started after the sqlite3_interrupt() call and before the
2281** running statements reaches zero are interrupted as if they had been
2282** running prior to the sqlite3_interrupt() call. ^New SQL statements
2283** that are started after the running statement count reaches zero are
2284** not effected by the sqlite3_interrupt().
2285** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2286** SQL statements is a no-op and has no effect on SQL statements
2287** that are started after the sqlite3_interrupt() call returns.
2288*/
2289SQLITE_API void sqlite3_interrupt(sqlite3*);
2290
2291/*
2292** CAPI3REF: Determine If An SQL Statement Is Complete
2293**
2294** These routines are useful during command-line input to determine if the
2295** currently entered text seems to form a complete SQL statement or
2296** if additional input is needed before sending the text into
2297** SQLite for parsing. ^These routines return 1 if the input string
2298** appears to be a complete SQL statement. ^A statement is judged to be
2299** complete if it ends with a semicolon token and is not a prefix of a
2300** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
2301** string literals or quoted identifier names or comments are not
2302** independent tokens (they are part of the token in which they are
2303** embedded) and thus do not count as a statement terminator. ^Whitespace
2304** and comments that follow the final semicolon are ignored.
2305**
2306** ^These routines return 0 if the statement is incomplete. ^If a
2307** memory allocation fails, then SQLITE_NOMEM is returned.
2308**
2309** ^These routines do not parse the SQL statements thus
2310** will not detect syntactically incorrect SQL.
2311**
2312** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2313** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2314** automatically by sqlite3_complete16(). If that initialization fails,
2315** then the return value from sqlite3_complete16() will be non-zero
2316** regardless of whether or not the input SQL is complete.)^
2317**
2318** The input to [sqlite3_complete()] must be a zero-terminated
2319** UTF-8 string.
2320**
2321** The input to [sqlite3_complete16()] must be a zero-terminated
2322** UTF-16 string in native byte order.
2323*/
2324SQLITE_API int sqlite3_complete(const char *sql);
2325SQLITE_API int sqlite3_complete16(const void *sql);
2326
2327/*
2328** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2329** KEYWORDS: {busy-handler callback} {busy handler}
2330** METHOD: sqlite3
2331**
2332** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2333** that might be invoked with argument P whenever
2334** an attempt is made to access a database table associated with
2335** [database connection] D when another thread
2336** or process has the table locked.
2337** The sqlite3_busy_handler() interface is used to implement
2338** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2339**
2340** ^If the busy callback is NULL, then [SQLITE_BUSY]
2341** is returned immediately upon encountering the lock. ^If the busy callback
2342** is not NULL, then the callback might be invoked with two arguments.
2343**
2344** ^The first argument to the busy handler is a copy of the void* pointer which
2345** is the third argument to sqlite3_busy_handler(). ^The second argument to
2346** the busy handler callback is the number of times that the busy handler has
2347** been invoked previously for the same locking event. ^If the
2348** busy callback returns 0, then no additional attempts are made to
2349** access the database and [SQLITE_BUSY] is returned
2350** to the application.
2351** ^If the callback returns non-zero, then another attempt
2352** is made to access the database and the cycle repeats.
2353**
2354** The presence of a busy handler does not guarantee that it will be invoked
2355** when there is lock contention. ^If SQLite determines that invoking the busy
2356** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2357** to the application instead of invoking the
2358** busy handler.
2359** Consider a scenario where one process is holding a read lock that
2360** it is trying to promote to a reserved lock and
2361** a second process is holding a reserved lock that it is trying
2362** to promote to an exclusive lock. The first process cannot proceed
2363** because it is blocked by the second and the second process cannot
2364** proceed because it is blocked by the first. If both processes
2365** invoke the busy handlers, neither will make any progress. Therefore,
2366** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2367** will induce the first process to release its read lock and allow
2368** the second process to proceed.
2369**
2370** ^The default busy callback is NULL.
2371**
2372** ^(There can only be a single busy handler defined for each
2373** [database connection]. Setting a new busy handler clears any
2374** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
2375** or evaluating [PRAGMA busy_timeout=N] will change the
2376** busy handler and thus clear any previously set busy handler.
2377**
2378** The busy callback should not take any actions which modify the
2379** database connection that invoked the busy handler. In other words,
2380** the busy handler is not reentrant. Any such actions
2381** result in undefined behavior.
2382**
2383** A busy handler must not close the database connection
2384** or [prepared statement] that invoked the busy handler.
2385*/
2386SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
2387
2388/*
2389** CAPI3REF: Set A Busy Timeout
2390** METHOD: sqlite3
2391**
2392** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2393** for a specified amount of time when a table is locked. ^The handler
2394** will sleep multiple times until at least "ms" milliseconds of sleeping
2395** have accumulated. ^After at least "ms" milliseconds of sleeping,
2396** the handler returns 0 which causes [sqlite3_step()] to return
2397** [SQLITE_BUSY].
2398**
2399** ^Calling this routine with an argument less than or equal to zero
2400** turns off all busy handlers.
2401**
2402** ^(There can only be a single busy handler for a particular
2403** [database connection] at any given moment. If another busy handler
2404** was defined (using [sqlite3_busy_handler()]) prior to calling
2405** this routine, that other busy handler is cleared.)^
2406**
2407** See also: [PRAGMA busy_timeout]
2408*/
2409SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2410
2411/*
2412** CAPI3REF: Convenience Routines For Running Queries
2413** METHOD: sqlite3
2414**
2415** This is a legacy interface that is preserved for backwards compatibility.
2416** Use of this interface is not recommended.
2417**
2418** Definition: A <b>result table</b> is memory data structure created by the
2419** [sqlite3_get_table()] interface. A result table records the
2420** complete query results from one or more queries.
2421**
2422** The table conceptually has a number of rows and columns. But
2423** these numbers are not part of the result table itself. These
2424** numbers are obtained separately. Let N be the number of rows
2425** and M be the number of columns.
2426**
2427** A result table is an array of pointers to zero-terminated UTF-8 strings.
2428** There are (N+1)*M elements in the array. The first M pointers point
2429** to zero-terminated strings that contain the names of the columns.
2430** The remaining entries all point to query results. NULL values result
2431** in NULL pointers. All other values are in their UTF-8 zero-terminated
2432** string representation as returned by [sqlite3_column_text()].
2433**
2434** A result table might consist of one or more memory allocations.
2435** It is not safe to pass a result table directly to [sqlite3_free()].
2436** A result table should be deallocated using [sqlite3_free_table()].
2437**
2438** ^(As an example of the result table format, suppose a query result
2439** is as follows:
2440**
2441** <blockquote><pre>
2442** Name | Age
2443** -----------------------
2444** Alice | 43
2445** Bob | 28
2446** Cindy | 21
2447** </pre></blockquote>
2448**
2449** There are two column (M==2) and three rows (N==3). Thus the
2450** result table has 8 entries. Suppose the result table is stored
2451** in an array names azResult. Then azResult holds this content:
2452**
2453** <blockquote><pre>
2454** azResult&#91;0] = "Name";
2455** azResult&#91;1] = "Age";
2456** azResult&#91;2] = "Alice";
2457** azResult&#91;3] = "43";
2458** azResult&#91;4] = "Bob";
2459** azResult&#91;5] = "28";
2460** azResult&#91;6] = "Cindy";
2461** azResult&#91;7] = "21";
2462** </pre></blockquote>)^
2463**
2464** ^The sqlite3_get_table() function evaluates one or more
2465** semicolon-separated SQL statements in the zero-terminated UTF-8
2466** string of its 2nd parameter and returns a result table to the
2467** pointer given in its 3rd parameter.
2468**
2469** After the application has finished with the result from sqlite3_get_table(),
2470** it must pass the result table pointer to sqlite3_free_table() in order to
2471** release the memory that was malloced. Because of the way the
2472** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2473** function must not try to call [sqlite3_free()] directly. Only
2474** [sqlite3_free_table()] is able to release the memory properly and safely.
2475**
2476** The sqlite3_get_table() interface is implemented as a wrapper around
2477** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
2478** to any internal data structures of SQLite. It uses only the public
2479** interface defined here. As a consequence, errors that occur in the
2480** wrapper layer outside of the internal [sqlite3_exec()] call are not
2481** reflected in subsequent calls to [sqlite3_errcode()] or
2482** [sqlite3_errmsg()].
2483*/
2484SQLITE_API int sqlite3_get_table(
2485 sqlite3 *db, /* An open database */
2486 const char *zSql, /* SQL to be evaluated */
2487 char ***pazResult, /* Results of the query */
2488 int *pnRow, /* Number of result rows written here */
2489 int *pnColumn, /* Number of result columns written here */
2490 char **pzErrmsg /* Error msg written here */
2491);
2492SQLITE_API void sqlite3_free_table(char **result);
2493
2494/*
2495** CAPI3REF: Formatted String Printing Functions
2496**
2497** These routines are work-alikes of the "printf()" family of functions
2498** from the standard C library.
2499** These routines understand most of the common K&R formatting options,
2500** plus some additional non-standard formats, detailed below.
2501** Note that some of the more obscure formatting options from recent
2502** C-library standards are omitted from this implementation.
2503**
2504** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2505** results into memory obtained from [sqlite3_malloc()].
2506** The strings returned by these two routines should be
2507** released by [sqlite3_free()]. ^Both routines return a
2508** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2509** memory to hold the resulting string.
2510**
2511** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2512** the standard C library. The result is written into the
2513** buffer supplied as the second parameter whose size is given by
2514** the first parameter. Note that the order of the
2515** first two parameters is reversed from snprintf().)^ This is an
2516** historical accident that cannot be fixed without breaking
2517** backwards compatibility. ^(Note also that sqlite3_snprintf()
2518** returns a pointer to its buffer instead of the number of
2519** characters actually written into the buffer.)^ We admit that
2520** the number of characters written would be a more useful return
2521** value but we cannot change the implementation of sqlite3_snprintf()
2522** now without breaking compatibility.
2523**
2524** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2525** guarantees that the buffer is always zero-terminated. ^The first
2526** parameter "n" is the total size of the buffer, including space for
2527** the zero terminator. So the longest string that can be completely
2528** written will be n-1 characters.
2529**
2530** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2531**
2532** These routines all implement some additional formatting
2533** options that are useful for constructing SQL statements.
2534** All of the usual printf() formatting options apply. In addition, there
2535** is are "%q", "%Q", "%w" and "%z" options.
2536**
2537** ^(The %q option works like %s in that it substitutes a nul-terminated
2538** string from the argument list. But %q also doubles every '\'' character.
2539** %q is designed for use inside a string literal.)^ By doubling each '\''
2540** character it escapes that character and allows it to be inserted into
2541** the string.
2542**
2543** For example, assume the string variable zText contains text as follows:
2544**
2545** <blockquote><pre>
2546** char *zText = "It's a happy day!";
2547** </pre></blockquote>
2548**
2549** One can use this text in an SQL statement as follows:
2550**
2551** <blockquote><pre>
2552** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2553** sqlite3_exec(db, zSQL, 0, 0, 0);
2554** sqlite3_free(zSQL);
2555** </pre></blockquote>
2556**
2557** Because the %q format string is used, the '\'' character in zText
2558** is escaped and the SQL generated is as follows:
2559**
2560** <blockquote><pre>
2561** INSERT INTO table1 VALUES('It''s a happy day!')
2562** </pre></blockquote>
2563**
2564** This is correct. Had we used %s instead of %q, the generated SQL
2565** would have looked like this:
2566**
2567** <blockquote><pre>
2568** INSERT INTO table1 VALUES('It's a happy day!');
2569** </pre></blockquote>
2570**
2571** This second example is an SQL syntax error. As a general rule you should
2572** always use %q instead of %s when inserting text into a string literal.
2573**
2574** ^(The %Q option works like %q except it also adds single quotes around
2575** the outside of the total string. Additionally, if the parameter in the
2576** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2577** single quotes).)^ So, for example, one could say:
2578**
2579** <blockquote><pre>
2580** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2581** sqlite3_exec(db, zSQL, 0, 0, 0);
2582** sqlite3_free(zSQL);
2583** </pre></blockquote>
2584**
2585** The code above will render a correct SQL statement in the zSQL
2586** variable even if the zText variable is a NULL pointer.
2587**
2588** ^(The "%w" formatting option is like "%q" except that it expects to
2589** be contained within double-quotes instead of single quotes, and it
2590** escapes the double-quote character instead of the single-quote
2591** character.)^ The "%w" formatting option is intended for safely inserting
2592** table and column names into a constructed SQL statement.
2593**
2594** ^(The "%z" formatting option works like "%s" but with the
2595** addition that after the string has been read and copied into
2596** the result, [sqlite3_free()] is called on the input string.)^
2597*/
2598SQLITE_API char *sqlite3_mprintf(const char*,...);
2599SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2600SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2601SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2602
2603/*
2604** CAPI3REF: Memory Allocation Subsystem
2605**
2606** The SQLite core uses these three routines for all of its own
2607** internal memory allocation needs. "Core" in the previous sentence
2608** does not include operating-system specific VFS implementation. The
2609** Windows VFS uses native malloc() and free() for some operations.
2610**
2611** ^The sqlite3_malloc() routine returns a pointer to a block
2612** of memory at least N bytes in length, where N is the parameter.
2613** ^If sqlite3_malloc() is unable to obtain sufficient free
2614** memory, it returns a NULL pointer. ^If the parameter N to
2615** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2616** a NULL pointer.
2617**
2618** ^The sqlite3_malloc64(N) routine works just like
2619** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2620** of a signed 32-bit integer.
2621**
2622** ^Calling sqlite3_free() with a pointer previously returned
2623** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2624** that it might be reused. ^The sqlite3_free() routine is
2625** a no-op if is called with a NULL pointer. Passing a NULL pointer
2626** to sqlite3_free() is harmless. After being freed, memory
2627** should neither be read nor written. Even reading previously freed
2628** memory might result in a segmentation fault or other severe error.
2629** Memory corruption, a segmentation fault, or other severe error
2630** might result if sqlite3_free() is called with a non-NULL pointer that
2631** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2632**
2633** ^The sqlite3_realloc(X,N) interface attempts to resize a
2634** prior memory allocation X to be at least N bytes.
2635** ^If the X parameter to sqlite3_realloc(X,N)
2636** is a NULL pointer then its behavior is identical to calling
2637** sqlite3_malloc(N).
2638** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2639** negative then the behavior is exactly the same as calling
2640** sqlite3_free(X).
2641** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2642** of at least N bytes in size or NULL if insufficient memory is available.
2643** ^If M is the size of the prior allocation, then min(N,M) bytes
2644** of the prior allocation are copied into the beginning of buffer returned
2645** by sqlite3_realloc(X,N) and the prior allocation is freed.
2646** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2647** prior allocation is not freed.
2648**
2649** ^The sqlite3_realloc64(X,N) interfaces works the same as
2650** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2651** of a 32-bit signed integer.
2652**
2653** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2654** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2655** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2656** ^The value returned by sqlite3_msize(X) might be larger than the number
2657** of bytes requested when X was allocated. ^If X is a NULL pointer then
2658** sqlite3_msize(X) returns zero. If X points to something that is not
2659** the beginning of memory allocation, or if it points to a formerly
2660** valid memory allocation that has now been freed, then the behavior
2661** of sqlite3_msize(X) is undefined and possibly harmful.
2662**
2663** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2664** sqlite3_malloc64(), and sqlite3_realloc64()
2665** is always aligned to at least an 8 byte boundary, or to a
2666** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2667** option is used.
2668**
2669** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2670** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2671** implementation of these routines to be omitted. That capability
2672** is no longer provided. Only built-in memory allocators can be used.
2673**
2674** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2675** the system malloc() and free() directly when converting
2676** filenames between the UTF-8 encoding used by SQLite
2677** and whatever filename encoding is used by the particular Windows
2678** installation. Memory allocation errors were detected, but
2679** they were reported back as [SQLITE_CANTOPEN] or
2680** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2681**
2682** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2683** must be either NULL or else pointers obtained from a prior
2684** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2685** not yet been released.
2686**
2687** The application must not read or write any part of
2688** a block of memory after it has been released using
2689** [sqlite3_free()] or [sqlite3_realloc()].
2690*/
2691SQLITE_API void *sqlite3_malloc(int);
2692SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
2693SQLITE_API void *sqlite3_realloc(void*, int);
2694SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
2695SQLITE_API void sqlite3_free(void*);
2696SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
2697
2698/*
2699** CAPI3REF: Memory Allocator Statistics
2700**
2701** SQLite provides these two interfaces for reporting on the status
2702** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2703** routines, which form the built-in memory allocation subsystem.
2704**
2705** ^The [sqlite3_memory_used()] routine returns the number of bytes
2706** of memory currently outstanding (malloced but not freed).
2707** ^The [sqlite3_memory_highwater()] routine returns the maximum
2708** value of [sqlite3_memory_used()] since the high-water mark
2709** was last reset. ^The values returned by [sqlite3_memory_used()] and
2710** [sqlite3_memory_highwater()] include any overhead
2711** added by SQLite in its implementation of [sqlite3_malloc()],
2712** but not overhead added by the any underlying system library
2713** routines that [sqlite3_malloc()] may call.
2714**
2715** ^The memory high-water mark is reset to the current value of
2716** [sqlite3_memory_used()] if and only if the parameter to
2717** [sqlite3_memory_highwater()] is true. ^The value returned
2718** by [sqlite3_memory_highwater(1)] is the high-water mark
2719** prior to the reset.
2720*/
2721SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2722SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2723
2724/*
2725** CAPI3REF: Pseudo-Random Number Generator
2726**
2727** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2728** select random [ROWID | ROWIDs] when inserting new records into a table that
2729** already uses the largest possible [ROWID]. The PRNG is also used for
2730** the build-in random() and randomblob() SQL functions. This interface allows
2731** applications to access the same PRNG for other purposes.
2732**
2733** ^A call to this routine stores N bytes of randomness into buffer P.
2734** ^The P parameter can be a NULL pointer.
2735**
2736** ^If this routine has not been previously called or if the previous
2737** call had N less than one or a NULL pointer for P, then the PRNG is
2738** seeded using randomness obtained from the xRandomness method of
2739** the default [sqlite3_vfs] object.
2740** ^If the previous call to this routine had an N of 1 or more and a
2741** non-NULL P then the pseudo-randomness is generated
2742** internally and without recourse to the [sqlite3_vfs] xRandomness
2743** method.
2744*/
2745SQLITE_API void sqlite3_randomness(int N, void *P);
2746
2747/*
2748** CAPI3REF: Compile-Time Authorization Callbacks
2749** METHOD: sqlite3
2750** KEYWORDS: {authorizer callback}
2751**
2752** ^This routine registers an authorizer callback with a particular
2753** [database connection], supplied in the first argument.
2754** ^The authorizer callback is invoked as SQL statements are being compiled
2755** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2756** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
2757** and [sqlite3_prepare16_v3()]. ^At various
2758** points during the compilation process, as logic is being created
2759** to perform various actions, the authorizer callback is invoked to
2760** see if those actions are allowed. ^The authorizer callback should
2761** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2762** specific action but allow the SQL statement to continue to be
2763** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2764** rejected with an error. ^If the authorizer callback returns
2765** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2766** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2767** the authorizer will fail with an error message.
2768**
2769** When the callback returns [SQLITE_OK], that means the operation
2770** requested is ok. ^When the callback returns [SQLITE_DENY], the
2771** [sqlite3_prepare_v2()] or equivalent call that triggered the
2772** authorizer will fail with an error message explaining that
2773** access is denied.
2774**
2775** ^The first parameter to the authorizer callback is a copy of the third
2776** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2777** to the callback is an integer [SQLITE_COPY | action code] that specifies
2778** the particular action to be authorized. ^The third through sixth parameters
2779** to the callback are either NULL pointers or zero-terminated strings
2780** that contain additional details about the action to be authorized.
2781** Applications must always be prepared to encounter a NULL pointer in any
2782** of the third through the sixth parameters of the authorization callback.
2783**
2784** ^If the action code is [SQLITE_READ]
2785** and the callback returns [SQLITE_IGNORE] then the
2786** [prepared statement] statement is constructed to substitute
2787** a NULL value in place of the table column that would have
2788** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2789** return can be used to deny an untrusted user access to individual
2790** columns of a table.
2791** ^When a table is referenced by a [SELECT] but no column values are
2792** extracted from that table (for example in a query like
2793** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
2794** is invoked once for that table with a column name that is an empty string.
2795** ^If the action code is [SQLITE_DELETE] and the callback returns
2796** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2797** [truncate optimization] is disabled and all rows are deleted individually.
2798**
2799** An authorizer is used when [sqlite3_prepare | preparing]
2800** SQL statements from an untrusted source, to ensure that the SQL statements
2801** do not try to access data they are not allowed to see, or that they do not
2802** try to execute malicious statements that damage the database. For
2803** example, an application may allow a user to enter arbitrary
2804** SQL queries for evaluation by a database. But the application does
2805** not want the user to be able to make arbitrary changes to the
2806** database. An authorizer could then be put in place while the
2807** user-entered SQL is being [sqlite3_prepare | prepared] that
2808** disallows everything except [SELECT] statements.
2809**
2810** Applications that need to process SQL from untrusted sources
2811** might also consider lowering resource limits using [sqlite3_limit()]
2812** and limiting database size using the [max_page_count] [PRAGMA]
2813** in addition to using an authorizer.
2814**
2815** ^(Only a single authorizer can be in place on a database connection
2816** at a time. Each call to sqlite3_set_authorizer overrides the
2817** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2818** The authorizer is disabled by default.
2819**
2820** The authorizer callback must not do anything that will modify
2821** the database connection that invoked the authorizer callback.
2822** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2823** database connections for the meaning of "modify" in this paragraph.
2824**
2825** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2826** statement might be re-prepared during [sqlite3_step()] due to a
2827** schema change. Hence, the application should ensure that the
2828** correct authorizer callback remains in place during the [sqlite3_step()].
2829**
2830** ^Note that the authorizer callback is invoked only during
2831** [sqlite3_prepare()] or its variants. Authorization is not
2832** performed during statement evaluation in [sqlite3_step()], unless
2833** as stated in the previous paragraph, sqlite3_step() invokes
2834** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2835*/
2836SQLITE_API int sqlite3_set_authorizer(
2837 sqlite3*,
2838 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2839 void *pUserData
2840);
2841
2842/*
2843** CAPI3REF: Authorizer Return Codes
2844**
2845** The [sqlite3_set_authorizer | authorizer callback function] must
2846** return either [SQLITE_OK] or one of these two constants in order
2847** to signal SQLite whether or not the action is permitted. See the
2848** [sqlite3_set_authorizer | authorizer documentation] for additional
2849** information.
2850**
2851** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2852** returned from the [sqlite3_vtab_on_conflict()] interface.
2853*/
2854#define SQLITE_DENY 1 /* Abort the SQL statement with an error */
2855#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
2856
2857/*
2858** CAPI3REF: Authorizer Action Codes
2859**
2860** The [sqlite3_set_authorizer()] interface registers a callback function
2861** that is invoked to authorize certain SQL statement actions. The
2862** second parameter to the callback is an integer code that specifies
2863** what action is being authorized. These are the integer action codes that
2864** the authorizer callback may be passed.
2865**
2866** These action code values signify what kind of operation is to be
2867** authorized. The 3rd and 4th parameters to the authorization
2868** callback function will be parameters or NULL depending on which of these
2869** codes is used as the second parameter. ^(The 5th parameter to the
2870** authorizer callback is the name of the database ("main", "temp",
2871** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2872** is the name of the inner-most trigger or view that is responsible for
2873** the access attempt or NULL if this access attempt is directly from
2874** top-level SQL code.
2875*/
2876/******************************************* 3rd ************ 4th ***********/
2877#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
2878#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
2879#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
2880#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
2881#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
2882#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
2883#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2884#define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2885#define SQLITE_DELETE 9 /* Table Name NULL */
2886#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2887#define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2888#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2889#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2890#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2891#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2892#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2893#define SQLITE_DROP_VIEW 17 /* View Name NULL */
2894#define SQLITE_INSERT 18 /* Table Name NULL */
2895#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2896#define SQLITE_READ 20 /* Table Name Column Name */
2897#define SQLITE_SELECT 21 /* NULL NULL */
2898#define SQLITE_TRANSACTION 22 /* Operation NULL */
2899#define SQLITE_UPDATE 23 /* Table Name Column Name */
2900#define SQLITE_ATTACH 24 /* Filename NULL */
2901#define SQLITE_DETACH 25 /* Database Name NULL */
2902#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2903#define SQLITE_REINDEX 27 /* Index Name NULL */
2904#define SQLITE_ANALYZE 28 /* Table Name NULL */
2905#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2906#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2907#define SQLITE_FUNCTION 31 /* NULL Function Name */
2908#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2909#define SQLITE_COPY 0 /* No longer used */
2910#define SQLITE_RECURSIVE 33 /* NULL NULL */
2911
2912/*
2913** CAPI3REF: Tracing And Profiling Functions
2914** METHOD: sqlite3
2915**
2916** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
2917** instead of the routines described here.
2918**
2919** These routines register callback functions that can be used for
2920** tracing and profiling the execution of SQL statements.
2921**
2922** ^The callback function registered by sqlite3_trace() is invoked at
2923** various times when an SQL statement is being run by [sqlite3_step()].
2924** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2925** SQL statement text as the statement first begins executing.
2926** ^(Additional sqlite3_trace() callbacks might occur
2927** as each triggered subprogram is entered. The callbacks for triggers
2928** contain a UTF-8 SQL comment that identifies the trigger.)^
2929**
2930** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2931** the length of [bound parameter] expansion in the output of sqlite3_trace().
2932**
2933** ^The callback function registered by sqlite3_profile() is invoked
2934** as each SQL statement finishes. ^The profile callback contains
2935** the original statement text and an estimate of wall-clock time
2936** of how long that statement took to run. ^The profile callback
2937** time is in units of nanoseconds, however the current implementation
2938** is only capable of millisecond resolution so the six least significant
2939** digits in the time are meaningless. Future versions of SQLite
2940** might provide greater resolution on the profiler callback. The
2941** sqlite3_profile() function is considered experimental and is
2942** subject to change in future versions of SQLite.
2943*/
2944SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
2945 void(*xTrace)(void*,const char*), void*);
2946SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
2947 void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2948
2949/*
2950** CAPI3REF: SQL Trace Event Codes
2951** KEYWORDS: SQLITE_TRACE
2952**
2953** These constants identify classes of events that can be monitored
2954** using the [sqlite3_trace_v2()] tracing logic. The M argument
2955** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
2956** the following constants. ^The first argument to the trace callback
2957** is one of the following constants.
2958**
2959** New tracing constants may be added in future releases.
2960**
2961** ^A trace callback has four arguments: xCallback(T,C,P,X).
2962** ^The T argument is one of the integer type codes above.
2963** ^The C argument is a copy of the context pointer passed in as the
2964** fourth argument to [sqlite3_trace_v2()].
2965** The P and X arguments are pointers whose meanings depend on T.
2966**
2967** <dl>
2968** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
2969** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
2970** first begins running and possibly at other times during the
2971** execution of the prepared statement, such as at the start of each
2972** trigger subprogram. ^The P argument is a pointer to the
2973** [prepared statement]. ^The X argument is a pointer to a string which
2974** is the unexpanded SQL text of the prepared statement or an SQL comment
2975** that indicates the invocation of a trigger. ^The callback can compute
2976** the same text that would have been returned by the legacy [sqlite3_trace()]
2977** interface by using the X argument when X begins with "--" and invoking
2978** [sqlite3_expanded_sql(P)] otherwise.
2979**
2980** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
2981** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
2982** information as is provided by the [sqlite3_profile()] callback.
2983** ^The P argument is a pointer to the [prepared statement] and the
2984** X argument points to a 64-bit integer which is the estimated of
2985** the number of nanosecond that the prepared statement took to run.
2986** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
2987**
2988** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
2989** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
2990** statement generates a single row of result.
2991** ^The P argument is a pointer to the [prepared statement] and the
2992** X argument is unused.
2993**
2994** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
2995** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
2996** connection closes.
2997** ^The P argument is a pointer to the [database connection] object
2998** and the X argument is unused.
2999** </dl>
3000*/
3001#define SQLITE_TRACE_STMT 0x01
3002#define SQLITE_TRACE_PROFILE 0x02
3003#define SQLITE_TRACE_ROW 0x04
3004#define SQLITE_TRACE_CLOSE 0x08
3005
3006/*
3007** CAPI3REF: SQL Trace Hook
3008** METHOD: sqlite3
3009**
3010** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
3011** function X against [database connection] D, using property mask M
3012** and context pointer P. ^If the X callback is
3013** NULL or if the M mask is zero, then tracing is disabled. The
3014** M argument should be the bitwise OR-ed combination of
3015** zero or more [SQLITE_TRACE] constants.
3016**
3017** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides
3018** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2().
3019**
3020** ^The X callback is invoked whenever any of the events identified by
3021** mask M occur. ^The integer return value from the callback is currently
3022** ignored, though this may change in future releases. Callback
3023** implementations should return zero to ensure future compatibility.
3024**
3025** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
3026** ^The T argument is one of the [SQLITE_TRACE]
3027** constants to indicate why the callback was invoked.
3028** ^The C argument is a copy of the context pointer.
3029** The P and X arguments are pointers whose meanings depend on T.
3030**
3031** The sqlite3_trace_v2() interface is intended to replace the legacy
3032** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
3033** are deprecated.
3034*/
3035SQLITE_API int sqlite3_trace_v2(
3036 sqlite3*,
3037 unsigned uMask,
3038 int(*xCallback)(unsigned,void*,void*,void*),
3039 void *pCtx
3040);
3041
3042/*
3043** CAPI3REF: Query Progress Callbacks
3044** METHOD: sqlite3
3045**
3046** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
3047** function X to be invoked periodically during long running calls to
3048** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
3049** database connection D. An example use for this
3050** interface is to keep a GUI updated during a large query.
3051**
3052** ^The parameter P is passed through as the only parameter to the
3053** callback function X. ^The parameter N is the approximate number of
3054** [virtual machine instructions] that are evaluated between successive
3055** invocations of the callback X. ^If N is less than one then the progress
3056** handler is disabled.
3057**
3058** ^Only a single progress handler may be defined at one time per
3059** [database connection]; setting a new progress handler cancels the
3060** old one. ^Setting parameter X to NULL disables the progress handler.
3061** ^The progress handler is also disabled by setting N to a value less
3062** than 1.
3063**
3064** ^If the progress callback returns non-zero, the operation is
3065** interrupted. This feature can be used to implement a
3066** "Cancel" button on a GUI progress dialog box.
3067**
3068** The progress handler callback must not do anything that will modify
3069** the database connection that invoked the progress handler.
3070** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3071** database connections for the meaning of "modify" in this paragraph.
3072**
3073*/
3074SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
3075
3076/*
3077** CAPI3REF: Opening A New Database Connection
3078** CONSTRUCTOR: sqlite3
3079**
3080** ^These routines open an SQLite database file as specified by the
3081** filename argument. ^The filename argument is interpreted as UTF-8 for
3082** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
3083** order for sqlite3_open16(). ^(A [database connection] handle is usually
3084** returned in *ppDb, even if an error occurs. The only exception is that
3085** if SQLite is unable to allocate memory to hold the [sqlite3] object,
3086** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
3087** object.)^ ^(If the database is opened (and/or created) successfully, then
3088** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
3089** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
3090** an English language description of the error following a failure of any
3091** of the sqlite3_open() routines.
3092**
3093** ^The default encoding will be UTF-8 for databases created using
3094** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases
3095** created using sqlite3_open16() will be UTF-16 in the native byte order.
3096**
3097** Whether or not an error occurs when it is opened, resources
3098** associated with the [database connection] handle should be released by
3099** passing it to [sqlite3_close()] when it is no longer required.
3100**
3101** The sqlite3_open_v2() interface works like sqlite3_open()
3102** except that it accepts two additional parameters for additional control
3103** over the new database connection. ^(The flags parameter to
3104** sqlite3_open_v2() can take one of
3105** the following three values, optionally combined with the
3106** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
3107** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
3108**
3109** <dl>
3110** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
3111** <dd>The database is opened in read-only mode. If the database does not
3112** already exist, an error is returned.</dd>)^
3113**
3114** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
3115** <dd>The database is opened for reading and writing if possible, or reading
3116** only if the file is write protected by the operating system. In either
3117** case the database must already exist, otherwise an error is returned.</dd>)^
3118**
3119** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
3120** <dd>The database is opened for reading and writing, and is created if
3121** it does not already exist. This is the behavior that is always used for
3122** sqlite3_open() and sqlite3_open16().</dd>)^
3123** </dl>
3124**
3125** If the 3rd parameter to sqlite3_open_v2() is not one of the
3126** combinations shown above optionally combined with other
3127** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
3128** then the behavior is undefined.
3129**
3130** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
3131** opens in the multi-thread [threading mode] as long as the single-thread
3132** mode has not been set at compile-time or start-time. ^If the
3133** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
3134** in the serialized [threading mode] unless single-thread was
3135** previously selected at compile-time or start-time.
3136** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
3137** eligible to use [shared cache mode], regardless of whether or not shared
3138** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
3139** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
3140** participate in [shared cache mode] even if it is enabled.
3141**
3142** ^The fourth parameter to sqlite3_open_v2() is the name of the
3143** [sqlite3_vfs] object that defines the operating system interface that
3144** the new database connection should use. ^If the fourth parameter is
3145** a NULL pointer then the default [sqlite3_vfs] object is used.
3146**
3147** ^If the filename is ":memory:", then a private, temporary in-memory database
3148** is created for the connection. ^This in-memory database will vanish when
3149** the database connection is closed. Future versions of SQLite might
3150** make use of additional special filenames that begin with the ":" character.
3151** It is recommended that when a database filename actually does begin with
3152** a ":" character you should prefix the filename with a pathname such as
3153** "./" to avoid ambiguity.
3154**
3155** ^If the filename is an empty string, then a private, temporary
3156** on-disk database will be created. ^This private database will be
3157** automatically deleted as soon as the database connection is closed.
3158**
3159** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
3160**
3161** ^If [URI filename] interpretation is enabled, and the filename argument
3162** begins with "file:", then the filename is interpreted as a URI. ^URI
3163** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
3164** set in the third argument to sqlite3_open_v2(), or if it has
3165** been enabled globally using the [SQLITE_CONFIG_URI] option with the
3166** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
3167** URI filename interpretation is turned off
3168** by default, but future releases of SQLite might enable URI filename
3169** interpretation by default. See "[URI filenames]" for additional
3170** information.
3171**
3172** URI filenames are parsed according to RFC 3986. ^If the URI contains an
3173** authority, then it must be either an empty string or the string
3174** "localhost". ^If the authority is not an empty string or "localhost", an
3175** error is returned to the caller. ^The fragment component of a URI, if
3176** present, is ignored.
3177**
3178** ^SQLite uses the path component of the URI as the name of the disk file
3179** which contains the database. ^If the path begins with a '/' character,
3180** then it is interpreted as an absolute path. ^If the path does not begin
3181** with a '/' (meaning that the authority section is omitted from the URI)
3182** then the path is interpreted as a relative path.
3183** ^(On windows, the first component of an absolute path
3184** is a drive specification (e.g. "C:").)^
3185**
3186** [[core URI query parameters]]
3187** The query component of a URI may contain parameters that are interpreted
3188** either by SQLite itself, or by a [VFS | custom VFS implementation].
3189** SQLite and its built-in [VFSes] interpret the
3190** following query parameters:
3191**
3192** <ul>
3193** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
3194** a VFS object that provides the operating system interface that should
3195** be used to access the database file on disk. ^If this option is set to
3196** an empty string the default VFS object is used. ^Specifying an unknown
3197** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
3198** present, then the VFS specified by the option takes precedence over
3199** the value passed as the fourth parameter to sqlite3_open_v2().
3200**
3201** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
3202** "rwc", or "memory". Attempting to set it to any other value is
3203** an error)^.
3204** ^If "ro" is specified, then the database is opened for read-only
3205** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
3206** third argument to sqlite3_open_v2(). ^If the mode option is set to
3207** "rw", then the database is opened for read-write (but not create)
3208** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
3209** been set. ^Value "rwc" is equivalent to setting both
3210** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
3211** set to "memory" then a pure [in-memory database] that never reads
3212** or writes from disk is used. ^It is an error to specify a value for
3213** the mode parameter that is less restrictive than that specified by
3214** the flags passed in the third parameter to sqlite3_open_v2().
3215**
3216** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
3217** "private". ^Setting it to "shared" is equivalent to setting the
3218** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
3219** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
3220** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
3221** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
3222** a URI filename, its value overrides any behavior requested by setting
3223** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
3224**
3225** <li> <b>psow</b>: ^The psow parameter indicates whether or not the
3226** [powersafe overwrite] property does or does not apply to the
3227** storage media on which the database file resides.
3228**
3229** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
3230** which if set disables file locking in rollback journal modes. This
3231** is useful for accessing a database on a filesystem that does not
3232** support locking. Caution: Database corruption might result if two
3233** or more processes write to the same database and any one of those
3234** processes uses nolock=1.
3235**
3236** <li> <b>immutable</b>: ^The immutable parameter is a boolean query
3237** parameter that indicates that the database file is stored on
3238** read-only media. ^When immutable is set, SQLite assumes that the
3239** database file cannot be changed, even by a process with higher
3240** privilege, and so the database is opened read-only and all locking
3241** and change detection is disabled. Caution: Setting the immutable
3242** property on a database file that does in fact change can result
3243** in incorrect query results and/or [SQLITE_CORRUPT] errors.
3244** See also: [SQLITE_IOCAP_IMMUTABLE].
3245**
3246** </ul>
3247**
3248** ^Specifying an unknown parameter in the query component of a URI is not an
3249** error. Future versions of SQLite might understand additional query
3250** parameters. See "[query parameters with special meaning to SQLite]" for
3251** additional information.
3252**
3253** [[URI filename examples]] <h3>URI filename examples</h3>
3254**
3255** <table border="1" align=center cellpadding=5>
3256** <tr><th> URI filenames <th> Results
3257** <tr><td> file:data.db <td>
3258** Open the file "data.db" in the current directory.
3259** <tr><td> file:/home/fred/data.db<br>
3260** file:///home/fred/data.db <br>
3261** file://localhost/home/fred/data.db <br> <td>
3262** Open the database file "/home/fred/data.db".
3263** <tr><td> file://darkstar/home/fred/data.db <td>
3264** An error. "darkstar" is not a recognized authority.
3265** <tr><td style="white-space:nowrap">
3266** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
3267** <td> Windows only: Open the file "data.db" on fred's desktop on drive
3268** C:. Note that the %20 escaping in this example is not strictly
3269** necessary - space characters can be used literally
3270** in URI filenames.
3271** <tr><td> file:data.db?mode=ro&cache=private <td>
3272** Open file "data.db" in the current directory for read-only access.
3273** Regardless of whether or not shared-cache mode is enabled by
3274** default, use a private cache.
3275** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
3276** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
3277** that uses dot-files in place of posix advisory locking.
3278** <tr><td> file:data.db?mode=readonly <td>
3279** An error. "readonly" is not a valid option for the "mode" parameter.
3280** </table>
3281**
3282** ^URI hexadecimal escape sequences (%HH) are supported within the path and
3283** query components of a URI. A hexadecimal escape sequence consists of a
3284** percent sign - "%" - followed by exactly two hexadecimal digits
3285** specifying an octet value. ^Before the path or query components of a
3286** URI filename are interpreted, they are encoded using UTF-8 and all
3287** hexadecimal escape sequences replaced by a single byte containing the
3288** corresponding octet. If this process generates an invalid UTF-8 encoding,
3289** the results are undefined.
3290**
3291** <b>Note to Windows users:</b> The encoding used for the filename argument
3292** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
3293** codepage is currently defined. Filenames containing international
3294** characters must be converted to UTF-8 prior to passing them into
3295** sqlite3_open() or sqlite3_open_v2().
3296**
3297** <b>Note to Windows Runtime users:</b> The temporary directory must be set
3298** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
3299** features that require the use of temporary files may fail.
3300**
3301** See also: [sqlite3_temp_directory]
3302*/
3303SQLITE_API int sqlite3_open(
3304 const char *filename, /* Database filename (UTF-8) */
3305 sqlite3 **ppDb /* OUT: SQLite db handle */
3306);
3307SQLITE_API int sqlite3_open16(
3308 const void *filename, /* Database filename (UTF-16) */
3309 sqlite3 **ppDb /* OUT: SQLite db handle */
3310);
3311SQLITE_API int sqlite3_open_v2(
3312 const char *filename, /* Database filename (UTF-8) */
3313 sqlite3 **ppDb, /* OUT: SQLite db handle */
3314 int flags, /* Flags */
3315 const char *zVfs /* Name of VFS module to use */
3316);
3317
3318/*
3319** CAPI3REF: Obtain Values For URI Parameters
3320**
3321** These are utility routines, useful to VFS implementations, that check
3322** to see if a database file was a URI that contained a specific query
3323** parameter, and if so obtains the value of that query parameter.
3324**
3325** If F is the database filename pointer passed into the xOpen() method of
3326** a VFS implementation when the flags parameter to xOpen() has one or
3327** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
3328** P is the name of the query parameter, then
3329** sqlite3_uri_parameter(F,P) returns the value of the P
3330** parameter if it exists or a NULL pointer if P does not appear as a
3331** query parameter on F. If P is a query parameter of F
3332** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3333** a pointer to an empty string.
3334**
3335** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3336** parameter and returns true (1) or false (0) according to the value
3337** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3338** value of query parameter P is one of "yes", "true", or "on" in any
3339** case or if the value begins with a non-zero number. The
3340** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3341** query parameter P is one of "no", "false", or "off" in any case or
3342** if the value begins with a numeric zero. If P is not a query
3343** parameter on F or if the value of P is does not match any of the
3344** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3345**
3346** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3347** 64-bit signed integer and returns that integer, or D if P does not
3348** exist. If the value of P is something other than an integer, then
3349** zero is returned.
3350**
3351** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3352** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
3353** is not a database file pathname pointer that SQLite passed into the xOpen
3354** VFS method, then the behavior of this routine is undefined and probably
3355** undesirable.
3356*/
3357SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3358SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3359SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3360
3361
3362/*
3363** CAPI3REF: Error Codes And Messages
3364** METHOD: sqlite3
3365**
3366** ^If the most recent sqlite3_* API call associated with
3367** [database connection] D failed, then the sqlite3_errcode(D) interface
3368** returns the numeric [result code] or [extended result code] for that
3369** API call.
3370** If the most recent API call was successful,
3371** then the return value from sqlite3_errcode() is undefined.
3372** ^The sqlite3_extended_errcode()
3373** interface is the same except that it always returns the
3374** [extended result code] even when extended result codes are
3375** disabled.
3376**
3377** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3378** text that describes the error, as either UTF-8 or UTF-16 respectively.
3379** ^(Memory to hold the error message string is managed internally.
3380** The application does not need to worry about freeing the result.
3381** However, the error string might be overwritten or deallocated by
3382** subsequent calls to other SQLite interface functions.)^
3383**
3384** ^The sqlite3_errstr() interface returns the English-language text
3385** that describes the [result code], as UTF-8.
3386** ^(Memory to hold the error message string is managed internally
3387** and must not be freed by the application)^.
3388**
3389** When the serialized [threading mode] is in use, it might be the
3390** case that a second error occurs on a separate thread in between
3391** the time of the first error and the call to these interfaces.
3392** When that happens, the second error will be reported since these
3393** interfaces always report the most recent result. To avoid
3394** this, each thread can obtain exclusive use of the [database connection] D
3395** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3396** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3397** all calls to the interfaces listed here are completed.
3398**
3399** If an interface fails with SQLITE_MISUSE, that means the interface
3400** was invoked incorrectly by the application. In that case, the
3401** error code and message may or may not be set.
3402*/
3403SQLITE_API int sqlite3_errcode(sqlite3 *db);
3404SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
3405SQLITE_API const char *sqlite3_errmsg(sqlite3*);
3406SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
3407SQLITE_API const char *sqlite3_errstr(int);
3408
3409/*
3410** CAPI3REF: Prepared Statement Object
3411** KEYWORDS: {prepared statement} {prepared statements}
3412**
3413** An instance of this object represents a single SQL statement that
3414** has been compiled into binary form and is ready to be evaluated.
3415**
3416** Think of each SQL statement as a separate computer program. The
3417** original SQL text is source code. A prepared statement object
3418** is the compiled object code. All SQL must be converted into a
3419** prepared statement before it can be run.
3420**
3421** The life-cycle of a prepared statement object usually goes like this:
3422**
3423** <ol>
3424** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
3425** <li> Bind values to [parameters] using the sqlite3_bind_*()
3426** interfaces.
3427** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3428** <li> Reset the prepared statement using [sqlite3_reset()] then go back
3429** to step 2. Do this zero or more times.
3430** <li> Destroy the object using [sqlite3_finalize()].
3431** </ol>
3432*/
3433typedef struct sqlite3_stmt sqlite3_stmt;
3434
3435/*
3436** CAPI3REF: Run-time Limits
3437** METHOD: sqlite3
3438**
3439** ^(This interface allows the size of various constructs to be limited
3440** on a connection by connection basis. The first parameter is the
3441** [database connection] whose limit is to be set or queried. The
3442** second parameter is one of the [limit categories] that define a
3443** class of constructs to be size limited. The third parameter is the
3444** new limit for that construct.)^
3445**
3446** ^If the new limit is a negative number, the limit is unchanged.
3447** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3448** [limits | hard upper bound]
3449** set at compile-time by a C preprocessor macro called
3450** [limits | SQLITE_MAX_<i>NAME</i>].
3451** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3452** ^Attempts to increase a limit above its hard upper bound are
3453** silently truncated to the hard upper bound.
3454**
3455** ^Regardless of whether or not the limit was changed, the
3456** [sqlite3_limit()] interface returns the prior value of the limit.
3457** ^Hence, to find the current value of a limit without changing it,
3458** simply invoke this interface with the third parameter set to -1.
3459**
3460** Run-time limits are intended for use in applications that manage
3461** both their own internal database and also databases that are controlled
3462** by untrusted external sources. An example application might be a
3463** web browser that has its own databases for storing history and
3464** separate databases controlled by JavaScript applications downloaded
3465** off the Internet. The internal databases can be given the
3466** large, default limits. Databases managed by external sources can
3467** be given much smaller limits designed to prevent a denial of service
3468** attack. Developers might also want to use the [sqlite3_set_authorizer()]
3469** interface to further control untrusted SQL. The size of the database
3470** created by an untrusted script can be contained using the
3471** [max_page_count] [PRAGMA].
3472**
3473** New run-time limit categories may be added in future releases.
3474*/
3475SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
3476
3477/*
3478** CAPI3REF: Run-Time Limit Categories
3479** KEYWORDS: {limit category} {*limit categories}
3480**
3481** These constants define various performance limits
3482** that can be lowered at run-time using [sqlite3_limit()].
3483** The synopsis of the meanings of the various limits is shown below.
3484** Additional information is available at [limits | Limits in SQLite].
3485**
3486** <dl>
3487** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3488** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3489**
3490** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3491** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3492**
3493** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3494** <dd>The maximum number of columns in a table definition or in the
3495** result set of a [SELECT] or the maximum number of columns in an index
3496** or in an ORDER BY or GROUP BY clause.</dd>)^
3497**
3498** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3499** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3500**
3501** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3502** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3503**
3504** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3505** <dd>The maximum number of instructions in a virtual machine program
3506** used to implement an SQL statement. If [sqlite3_prepare_v2()] or
3507** the equivalent tries to allocate space for more than this many opcodes
3508** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
3509**
3510** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3511** <dd>The maximum number of arguments on a function.</dd>)^
3512**
3513** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3514** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3515**
3516** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3517** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3518** <dd>The maximum length of the pattern argument to the [LIKE] or
3519** [GLOB] operators.</dd>)^
3520**
3521** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3522** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3523** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3524**
3525** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3526** <dd>The maximum depth of recursion for triggers.</dd>)^
3527**
3528** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
3529** <dd>The maximum number of auxiliary worker threads that a single
3530** [prepared statement] may start.</dd>)^
3531** </dl>
3532*/
3533#define SQLITE_LIMIT_LENGTH 0
3534#define SQLITE_LIMIT_SQL_LENGTH 1
3535#define SQLITE_LIMIT_COLUMN 2
3536#define SQLITE_LIMIT_EXPR_DEPTH 3
3537#define SQLITE_LIMIT_COMPOUND_SELECT 4
3538#define SQLITE_LIMIT_VDBE_OP 5
3539#define SQLITE_LIMIT_FUNCTION_ARG 6
3540#define SQLITE_LIMIT_ATTACHED 7
3541#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
3542#define SQLITE_LIMIT_VARIABLE_NUMBER 9
3543#define SQLITE_LIMIT_TRIGGER_DEPTH 10
3544#define SQLITE_LIMIT_WORKER_THREADS 11
3545
3546/*
3547** CAPI3REF: Prepare Flags
3548**
3549** These constants define various flags that can be passed into
3550** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
3551** [sqlite3_prepare16_v3()] interfaces.
3552**
3553** New flags may be added in future releases of SQLite.
3554**
3555** <dl>
3556** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
3557** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
3558** that the prepared statement will be retained for a long time and
3559** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
3560** and [sqlite3_prepare16_v3()] assume that the prepared statement will
3561** be used just once or at most a few times and then destroyed using
3562** [sqlite3_finalize()] relatively soon. The current implementation acts
3563** on this hint by avoiding the use of [lookaside memory] so as not to
3564** deplete the limited store of lookaside memory. Future versions of
3565** SQLite may act on this hint differently.
3566** </dl>
3567*/
3568#define SQLITE_PREPARE_PERSISTENT 0x01
3569
3570/*
3571** CAPI3REF: Compiling An SQL Statement
3572** KEYWORDS: {SQL statement compiler}
3573** METHOD: sqlite3
3574** CONSTRUCTOR: sqlite3_stmt
3575**
3576** To execute an SQL statement, it must first be compiled into a byte-code
3577** program using one of these routines. Or, in other words, these routines
3578** are constructors for the [prepared statement] object.
3579**
3580** The preferred routine to use is [sqlite3_prepare_v2()]. The
3581** [sqlite3_prepare()] interface is legacy and should be avoided.
3582** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
3583** for special purposes.
3584**
3585** The use of the UTF-8 interfaces is preferred, as SQLite currently
3586** does all parsing using UTF-8. The UTF-16 interfaces are provided
3587** as a convenience. The UTF-16 interfaces work by converting the
3588** input text into UTF-8, then invoking the corresponding UTF-8 interface.
3589**
3590** The first argument, "db", is a [database connection] obtained from a
3591** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3592** [sqlite3_open16()]. The database connection must not have been closed.
3593**
3594** The second argument, "zSql", is the statement to be compiled, encoded
3595** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(),
3596** and sqlite3_prepare_v3()
3597** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
3598** and sqlite3_prepare16_v3() use UTF-16.
3599**
3600** ^If the nByte argument is negative, then zSql is read up to the
3601** first zero terminator. ^If nByte is positive, then it is the
3602** number of bytes read from zSql. ^If nByte is zero, then no prepared
3603** statement is generated.
3604** If the caller knows that the supplied string is nul-terminated, then
3605** there is a small performance advantage to passing an nByte parameter that
3606** is the number of bytes in the input string <i>including</i>
3607** the nul-terminator.
3608**
3609** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3610** past the end of the first SQL statement in zSql. These routines only
3611** compile the first statement in zSql, so *pzTail is left pointing to
3612** what remains uncompiled.
3613**
3614** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3615** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
3616** to NULL. ^If the input text contains no SQL (if the input is an empty
3617** string or a comment) then *ppStmt is set to NULL.
3618** The calling procedure is responsible for deleting the compiled
3619** SQL statement using [sqlite3_finalize()] after it has finished with it.
3620** ppStmt may not be NULL.
3621**
3622** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3623** otherwise an [error code] is returned.
3624**
3625** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
3626** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
3627** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
3628** are retained for backwards compatibility, but their use is discouraged.
3629** ^In the "vX" interfaces, the prepared statement
3630** that is returned (the [sqlite3_stmt] object) contains a copy of the
3631** original SQL text. This causes the [sqlite3_step()] interface to
3632** behave differently in three ways:
3633**
3634** <ol>
3635** <li>
3636** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3637** always used to do, [sqlite3_step()] will automatically recompile the SQL
3638** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3639** retries will occur before sqlite3_step() gives up and returns an error.
3640** </li>
3641**
3642** <li>
3643** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3644** [error codes] or [extended error codes]. ^The legacy behavior was that
3645** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3646** and the application would have to make a second call to [sqlite3_reset()]
3647** in order to find the underlying cause of the problem. With the "v2" prepare
3648** interfaces, the underlying reason for the error is returned immediately.
3649** </li>
3650**
3651** <li>
3652** ^If the specific value bound to [parameter | host parameter] in the
3653** WHERE clause might influence the choice of query plan for a statement,
3654** then the statement will be automatically recompiled, as if there had been
3655** a schema change, on the first [sqlite3_step()] call following any change
3656** to the [sqlite3_bind_text | bindings] of that [parameter].
3657** ^The specific value of WHERE-clause [parameter] might influence the
3658** choice of query plan if the parameter is the left-hand side of a [LIKE]
3659** or [GLOB] operator or if the parameter is compared to an indexed column
3660** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3661** </li>
3662**
3663** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
3664** the extra prepFlags parameter, which is a bit array consisting of zero or
3665** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The
3666** sqlite3_prepare_v2() interface works exactly the same as
3667** sqlite3_prepare_v3() with a zero prepFlags parameter.
3668** </ol>
3669*/
3670SQLITE_API int sqlite3_prepare(
3671 sqlite3 *db, /* Database handle */
3672 const char *zSql, /* SQL statement, UTF-8 encoded */
3673 int nByte, /* Maximum length of zSql in bytes. */
3674 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3675 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3676);
3677SQLITE_API int sqlite3_prepare_v2(
3678 sqlite3 *db, /* Database handle */
3679 const char *zSql, /* SQL statement, UTF-8 encoded */
3680 int nByte, /* Maximum length of zSql in bytes. */
3681 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3682 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3683);
3684SQLITE_API int sqlite3_prepare_v3(
3685 sqlite3 *db, /* Database handle */
3686 const char *zSql, /* SQL statement, UTF-8 encoded */
3687 int nByte, /* Maximum length of zSql in bytes. */
3688 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
3689 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3690 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3691);
3692SQLITE_API int sqlite3_prepare16(
3693 sqlite3 *db, /* Database handle */
3694 const void *zSql, /* SQL statement, UTF-16 encoded */
3695 int nByte, /* Maximum length of zSql in bytes. */
3696 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3697 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3698);
3699SQLITE_API int sqlite3_prepare16_v2(
3700 sqlite3 *db, /* Database handle */
3701 const void *zSql, /* SQL statement, UTF-16 encoded */
3702 int nByte, /* Maximum length of zSql in bytes. */
3703 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3704 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3705);
3706SQLITE_API int sqlite3_prepare16_v3(
3707 sqlite3 *db, /* Database handle */
3708 const void *zSql, /* SQL statement, UTF-16 encoded */
3709 int nByte, /* Maximum length of zSql in bytes. */
3710 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
3711 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3712 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3713);
3714
3715/*
3716** CAPI3REF: Retrieving Statement SQL
3717** METHOD: sqlite3_stmt
3718**
3719** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
3720** SQL text used to create [prepared statement] P if P was
3721** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
3722** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
3723** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
3724** string containing the SQL text of prepared statement P with
3725** [bound parameters] expanded.
3726**
3727** ^(For example, if a prepared statement is created using the SQL
3728** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
3729** and parameter :xyz is unbound, then sqlite3_sql() will return
3730** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
3731** will return "SELECT 2345,NULL".)^
3732**
3733** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
3734** is available to hold the result, or if the result would exceed the
3735** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
3736**
3737** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
3738** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time
3739** option causes sqlite3_expanded_sql() to always return NULL.
3740**
3741** ^The string returned by sqlite3_sql(P) is managed by SQLite and is
3742** automatically freed when the prepared statement is finalized.
3743** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
3744** is obtained from [sqlite3_malloc()] and must be free by the application
3745** by passing it to [sqlite3_free()].
3746*/
3747SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
3748SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
3749
3750/*
3751** CAPI3REF: Determine If An SQL Statement Writes The Database
3752** METHOD: sqlite3_stmt
3753**
3754** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3755** and only if the [prepared statement] X makes no direct changes to
3756** the content of the database file.
3757**
3758** Note that [application-defined SQL functions] or
3759** [virtual tables] might change the database indirectly as a side effect.
3760** ^(For example, if an application defines a function "eval()" that
3761** calls [sqlite3_exec()], then the following SQL statement would
3762** change the database file through side-effects:
3763**
3764** <blockquote><pre>
3765** SELECT eval('DELETE FROM t1') FROM t2;
3766** </pre></blockquote>
3767**
3768** But because the [SELECT] statement does not change the database file
3769** directly, sqlite3_stmt_readonly() would still return true.)^
3770**
3771** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3772** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3773** since the statements themselves do not actually modify the database but
3774** rather they control the timing of when other statements modify the
3775** database. ^The [ATTACH] and [DETACH] statements also cause
3776** sqlite3_stmt_readonly() to return true since, while those statements
3777** change the configuration of a database connection, they do not make
3778** changes to the content of the database files on disk.
3779** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
3780** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
3781** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
3782** sqlite3_stmt_readonly() returns false for those commands.
3783*/
3784SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3785
3786/*
3787** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3788** METHOD: sqlite3_stmt
3789**
3790** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3791** [prepared statement] S has been stepped at least once using
3792** [sqlite3_step(S)] but has neither run to completion (returned
3793** [SQLITE_DONE] from [sqlite3_step(S)]) nor
3794** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
3795** interface returns false if S is a NULL pointer. If S is not a
3796** NULL pointer and is not a pointer to a valid [prepared statement]
3797** object, then the behavior is undefined and probably undesirable.
3798**
3799** This interface can be used in combination [sqlite3_next_stmt()]
3800** to locate all prepared statements associated with a database
3801** connection that are in need of being reset. This can be used,
3802** for example, in diagnostic routines to search for prepared
3803** statements that are holding a transaction open.
3804*/
3805SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
3806
3807/*
3808** CAPI3REF: Dynamically Typed Value Object
3809** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3810**
3811** SQLite uses the sqlite3_value object to represent all values
3812** that can be stored in a database table. SQLite uses dynamic typing
3813** for the values it stores. ^Values stored in sqlite3_value objects
3814** can be integers, floating point values, strings, BLOBs, or NULL.
3815**
3816** An sqlite3_value object may be either "protected" or "unprotected".
3817** Some interfaces require a protected sqlite3_value. Other interfaces
3818** will accept either a protected or an unprotected sqlite3_value.
3819** Every interface that accepts sqlite3_value arguments specifies
3820** whether or not it requires a protected sqlite3_value. The
3821** [sqlite3_value_dup()] interface can be used to construct a new
3822** protected sqlite3_value from an unprotected sqlite3_value.
3823**
3824** The terms "protected" and "unprotected" refer to whether or not
3825** a mutex is held. An internal mutex is held for a protected
3826** sqlite3_value object but no mutex is held for an unprotected
3827** sqlite3_value object. If SQLite is compiled to be single-threaded
3828** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3829** or if SQLite is run in one of reduced mutex modes
3830** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3831** then there is no distinction between protected and unprotected
3832** sqlite3_value objects and they can be used interchangeably. However,
3833** for maximum code portability it is recommended that applications
3834** still make the distinction between protected and unprotected
3835** sqlite3_value objects even when not strictly required.
3836**
3837** ^The sqlite3_value objects that are passed as parameters into the
3838** implementation of [application-defined SQL functions] are protected.
3839** ^The sqlite3_value object returned by
3840** [sqlite3_column_value()] is unprotected.
3841** Unprotected sqlite3_value objects may only be used as arguments
3842** to [sqlite3_result_value()], [sqlite3_bind_value()], and
3843** [sqlite3_value_dup()].
3844** The [sqlite3_value_blob | sqlite3_value_type()] family of
3845** interfaces require protected sqlite3_value objects.
3846*/
3847typedef struct sqlite3_value sqlite3_value;
3848
3849/*
3850** CAPI3REF: SQL Function Context Object
3851**
3852** The context in which an SQL function executes is stored in an
3853** sqlite3_context object. ^A pointer to an sqlite3_context object
3854** is always first parameter to [application-defined SQL functions].
3855** The application-defined SQL function implementation will pass this
3856** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3857** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3858** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3859** and/or [sqlite3_set_auxdata()].
3860*/
3861typedef struct sqlite3_context sqlite3_context;
3862
3863/*
3864** CAPI3REF: Binding Values To Prepared Statements
3865** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3866** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3867** METHOD: sqlite3_stmt
3868**
3869** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3870** literals may be replaced by a [parameter] that matches one of following
3871** templates:
3872**
3873** <ul>
3874** <li> ?
3875** <li> ?NNN
3876** <li> :VVV
3877** <li> @VVV
3878** <li> $VVV
3879** </ul>
3880**
3881** In the templates above, NNN represents an integer literal,
3882** and VVV represents an alphanumeric identifier.)^ ^The values of these
3883** parameters (also called "host parameter names" or "SQL parameters")
3884** can be set using the sqlite3_bind_*() routines defined here.
3885**
3886** ^The first argument to the sqlite3_bind_*() routines is always
3887** a pointer to the [sqlite3_stmt] object returned from
3888** [sqlite3_prepare_v2()] or its variants.
3889**
3890** ^The second argument is the index of the SQL parameter to be set.
3891** ^The leftmost SQL parameter has an index of 1. ^When the same named
3892** SQL parameter is used more than once, second and subsequent
3893** occurrences have the same index as the first occurrence.
3894** ^The index for named parameters can be looked up using the
3895** [sqlite3_bind_parameter_index()] API if desired. ^The index
3896** for "?NNN" parameters is the value of NNN.
3897** ^The NNN value must be between 1 and the [sqlite3_limit()]
3898** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3899**
3900** ^The third argument is the value to bind to the parameter.
3901** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3902** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3903** is ignored and the end result is the same as sqlite3_bind_null().
3904**
3905** ^(In those routines that have a fourth argument, its value is the
3906** number of bytes in the parameter. To be clear: the value is the
3907** number of <u>bytes</u> in the value, not the number of characters.)^
3908** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3909** is negative, then the length of the string is
3910** the number of bytes up to the first zero terminator.
3911** If the fourth parameter to sqlite3_bind_blob() is negative, then
3912** the behavior is undefined.
3913** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3914** or sqlite3_bind_text16() or sqlite3_bind_text64() then
3915** that parameter must be the byte offset
3916** where the NUL terminator would occur assuming the string were NUL
3917** terminated. If any NUL characters occur at byte offsets less than
3918** the value of the fourth parameter then the resulting string value will
3919** contain embedded NULs. The result of expressions involving strings
3920** with embedded NULs is undefined.
3921**
3922** ^The fifth argument to the BLOB and string binding interfaces
3923** is a destructor used to dispose of the BLOB or
3924** string after SQLite has finished with it. ^The destructor is called
3925** to dispose of the BLOB or string even if the call to bind API fails.
3926** ^If the fifth argument is
3927** the special value [SQLITE_STATIC], then SQLite assumes that the
3928** information is in static, unmanaged space and does not need to be freed.
3929** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3930** SQLite makes its own private copy of the data immediately, before
3931** the sqlite3_bind_*() routine returns.
3932**
3933** ^The sixth argument to sqlite3_bind_text64() must be one of
3934** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
3935** to specify the encoding of the text in the third parameter. If
3936** the sixth argument to sqlite3_bind_text64() is not one of the
3937** allowed values shown above, or if the text encoding is different
3938** from the encoding specified by the sixth parameter, then the behavior
3939** is undefined.
3940**
3941** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3942** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
3943** (just an integer to hold its size) while it is being processed.
3944** Zeroblobs are intended to serve as placeholders for BLOBs whose
3945** content is later written using
3946** [sqlite3_blob_open | incremental BLOB I/O] routines.
3947** ^A negative value for the zeroblob results in a zero-length BLOB.
3948**
3949** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
3950** [prepared statement] S to have an SQL value of NULL, but to also be
3951** associated with the pointer P of type T. ^D is either a NULL pointer or
3952** a pointer to a destructor function for P. ^SQLite will invoke the
3953** destructor D with a single argument of P when it is finished using
3954** P. The T parameter should be a static string, preferably a string
3955** literal. The sqlite3_bind_pointer() routine is part of the
3956** [pointer passing interface] added for SQLite 3.20.0.
3957**
3958** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3959** for the [prepared statement] or with a prepared statement for which
3960** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3961** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
3962** routine is passed a [prepared statement] that has been finalized, the
3963** result is undefined and probably harmful.
3964**
3965** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3966** ^Unbound parameters are interpreted as NULL.
3967**
3968** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3969** [error code] if anything goes wrong.
3970** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
3971** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
3972** [SQLITE_MAX_LENGTH].
3973** ^[SQLITE_RANGE] is returned if the parameter
3974** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
3975**
3976** See also: [sqlite3_bind_parameter_count()],
3977** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3978*/
3979SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3980SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
3981 void(*)(void*));
3982SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
3983SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
3984SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3985SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
3986SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
3987SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3988SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
3989 void(*)(void*), unsigned char encoding);
3990SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3991SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
3992SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3993SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
3994
3995/*
3996** CAPI3REF: Number Of SQL Parameters
3997** METHOD: sqlite3_stmt
3998**
3999** ^This routine can be used to find the number of [SQL parameters]
4000** in a [prepared statement]. SQL parameters are tokens of the
4001** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
4002** placeholders for values that are [sqlite3_bind_blob | bound]
4003** to the parameters at a later time.
4004**
4005** ^(This routine actually returns the index of the largest (rightmost)
4006** parameter. For all forms except ?NNN, this will correspond to the
4007** number of unique parameters. If parameters of the ?NNN form are used,
4008** there may be gaps in the list.)^
4009**
4010** See also: [sqlite3_bind_blob|sqlite3_bind()],
4011** [sqlite3_bind_parameter_name()], and
4012** [sqlite3_bind_parameter_index()].
4013*/
4014SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
4015
4016/*
4017** CAPI3REF: Name Of A Host Parameter
4018** METHOD: sqlite3_stmt
4019**
4020** ^The sqlite3_bind_parameter_name(P,N) interface returns
4021** the name of the N-th [SQL parameter] in the [prepared statement] P.
4022** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
4023** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
4024** respectively.
4025** In other words, the initial ":" or "$" or "@" or "?"
4026** is included as part of the name.)^
4027** ^Parameters of the form "?" without a following integer have no name
4028** and are referred to as "nameless" or "anonymous parameters".
4029**
4030** ^The first host parameter has an index of 1, not 0.
4031**
4032** ^If the value N is out of range or if the N-th parameter is
4033** nameless, then NULL is returned. ^The returned string is
4034** always in UTF-8 encoding even if the named parameter was
4035** originally specified as UTF-16 in [sqlite3_prepare16()],
4036** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4037**
4038** See also: [sqlite3_bind_blob|sqlite3_bind()],
4039** [sqlite3_bind_parameter_count()], and
4040** [sqlite3_bind_parameter_index()].
4041*/
4042SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
4043
4044/*
4045** CAPI3REF: Index Of A Parameter With A Given Name
4046** METHOD: sqlite3_stmt
4047**
4048** ^Return the index of an SQL parameter given its name. ^The
4049** index value returned is suitable for use as the second
4050** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
4051** is returned if no matching parameter is found. ^The parameter
4052** name must be given in UTF-8 even if the original statement
4053** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
4054** [sqlite3_prepare16_v3()].
4055**
4056** See also: [sqlite3_bind_blob|sqlite3_bind()],
4057** [sqlite3_bind_parameter_count()], and
4058** [sqlite3_bind_parameter_name()].
4059*/
4060SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
4061
4062/*
4063** CAPI3REF: Reset All Bindings On A Prepared Statement
4064** METHOD: sqlite3_stmt
4065**
4066** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
4067** the [sqlite3_bind_blob | bindings] on a [prepared statement].
4068** ^Use this routine to reset all host parameters to NULL.
4069*/
4070SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
4071
4072/*
4073** CAPI3REF: Number Of Columns In A Result Set
4074** METHOD: sqlite3_stmt
4075**
4076** ^Return the number of columns in the result set returned by the
4077** [prepared statement]. ^If this routine returns 0, that means the
4078** [prepared statement] returns no data (for example an [UPDATE]).
4079** ^However, just because this routine returns a positive number does not
4080** mean that one or more rows of data will be returned. ^A SELECT statement
4081** will always have a positive sqlite3_column_count() but depending on the
4082** WHERE clause constraints and the table content, it might return no rows.
4083**
4084** See also: [sqlite3_data_count()]
4085*/
4086SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
4087
4088/*
4089** CAPI3REF: Column Names In A Result Set
4090** METHOD: sqlite3_stmt
4091**
4092** ^These routines return the name assigned to a particular column
4093** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
4094** interface returns a pointer to a zero-terminated UTF-8 string
4095** and sqlite3_column_name16() returns a pointer to a zero-terminated
4096** UTF-16 string. ^The first parameter is the [prepared statement]
4097** that implements the [SELECT] statement. ^The second parameter is the
4098** column number. ^The leftmost column is number 0.
4099**
4100** ^The returned string pointer is valid until either the [prepared statement]
4101** is destroyed by [sqlite3_finalize()] or until the statement is automatically
4102** reprepared by the first call to [sqlite3_step()] for a particular run
4103** or until the next call to
4104** sqlite3_column_name() or sqlite3_column_name16() on the same column.
4105**
4106** ^If sqlite3_malloc() fails during the processing of either routine
4107** (for example during a conversion from UTF-8 to UTF-16) then a
4108** NULL pointer is returned.
4109**
4110** ^The name of a result column is the value of the "AS" clause for
4111** that column, if there is an AS clause. If there is no AS clause
4112** then the name of the column is unspecified and may change from
4113** one release of SQLite to the next.
4114*/
4115SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
4116SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
4117
4118/*
4119** CAPI3REF: Source Of Data In A Query Result
4120** METHOD: sqlite3_stmt
4121**
4122** ^These routines provide a means to determine the database, table, and
4123** table column that is the origin of a particular result column in
4124** [SELECT] statement.
4125** ^The name of the database or table or column can be returned as
4126** either a UTF-8 or UTF-16 string. ^The _database_ routines return
4127** the database name, the _table_ routines return the table name, and
4128** the origin_ routines return the column name.
4129** ^The returned string is valid until the [prepared statement] is destroyed
4130** using [sqlite3_finalize()] or until the statement is automatically
4131** reprepared by the first call to [sqlite3_step()] for a particular run
4132** or until the same information is requested
4133** again in a different encoding.
4134**
4135** ^The names returned are the original un-aliased names of the
4136** database, table, and column.
4137**
4138** ^The first argument to these interfaces is a [prepared statement].
4139** ^These functions return information about the Nth result column returned by
4140** the statement, where N is the second function argument.
4141** ^The left-most column is column 0 for these routines.
4142**
4143** ^If the Nth column returned by the statement is an expression or
4144** subquery and is not a column value, then all of these functions return
4145** NULL. ^These routine might also return NULL if a memory allocation error
4146** occurs. ^Otherwise, they return the name of the attached database, table,
4147** or column that query result column was extracted from.
4148**
4149** ^As with all other SQLite APIs, those whose names end with "16" return
4150** UTF-16 encoded strings and the other functions return UTF-8.
4151**
4152** ^These APIs are only available if the library was compiled with the
4153** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
4154**
4155** If two or more threads call one or more of these routines against the same
4156** prepared statement and column at the same time then the results are
4157** undefined.
4158**
4159** If two or more threads call one or more
4160** [sqlite3_column_database_name | column metadata interfaces]
4161** for the same [prepared statement] and result column
4162** at the same time then the results are undefined.
4163*/
4164SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
4165SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
4166SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
4167SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
4168SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
4169SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
4170
4171/*
4172** CAPI3REF: Declared Datatype Of A Query Result
4173** METHOD: sqlite3_stmt
4174**
4175** ^(The first parameter is a [prepared statement].
4176** If this statement is a [SELECT] statement and the Nth column of the
4177** returned result set of that [SELECT] is a table column (not an
4178** expression or subquery) then the declared type of the table
4179** column is returned.)^ ^If the Nth column of the result set is an
4180** expression or subquery, then a NULL pointer is returned.
4181** ^The returned string is always UTF-8 encoded.
4182**
4183** ^(For example, given the database schema:
4184**
4185** CREATE TABLE t1(c1 VARIANT);
4186**
4187** and the following statement to be compiled:
4188**
4189** SELECT c1 + 1, c1 FROM t1;
4190**
4191** this routine would return the string "VARIANT" for the second result
4192** column (i==1), and a NULL pointer for the first result column (i==0).)^
4193**
4194** ^SQLite uses dynamic run-time typing. ^So just because a column
4195** is declared to contain a particular type does not mean that the
4196** data stored in that column is of the declared type. SQLite is
4197** strongly typed, but the typing is dynamic not static. ^Type
4198** is associated with individual values, not with the containers
4199** used to hold those values.
4200*/
4201SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
4202SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
4203
4204/*
4205** CAPI3REF: Evaluate An SQL Statement
4206** METHOD: sqlite3_stmt
4207**
4208** After a [prepared statement] has been prepared using any of
4209** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
4210** or [sqlite3_prepare16_v3()] or one of the legacy
4211** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
4212** must be called one or more times to evaluate the statement.
4213**
4214** The details of the behavior of the sqlite3_step() interface depend
4215** on whether the statement was prepared using the newer "vX" interfaces
4216** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
4217** [sqlite3_prepare16_v2()] or the older legacy
4218** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
4219** new "vX" interface is recommended for new applications but the legacy
4220** interface will continue to be supported.
4221**
4222** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
4223** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
4224** ^With the "v2" interface, any of the other [result codes] or
4225** [extended result codes] might be returned as well.
4226**
4227** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
4228** database locks it needs to do its job. ^If the statement is a [COMMIT]
4229** or occurs outside of an explicit transaction, then you can retry the
4230** statement. If the statement is not a [COMMIT] and occurs within an
4231** explicit transaction then you should rollback the transaction before
4232** continuing.
4233**
4234** ^[SQLITE_DONE] means that the statement has finished executing
4235** successfully. sqlite3_step() should not be called again on this virtual
4236** machine without first calling [sqlite3_reset()] to reset the virtual
4237** machine back to its initial state.
4238**
4239** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
4240** is returned each time a new row of data is ready for processing by the
4241** caller. The values may be accessed using the [column access functions].
4242** sqlite3_step() is called again to retrieve the next row of data.
4243**
4244** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
4245** violation) has occurred. sqlite3_step() should not be called again on
4246** the VM. More information may be found by calling [sqlite3_errmsg()].
4247** ^With the legacy interface, a more specific error code (for example,
4248** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
4249** can be obtained by calling [sqlite3_reset()] on the
4250** [prepared statement]. ^In the "v2" interface,
4251** the more specific error code is returned directly by sqlite3_step().
4252**
4253** [SQLITE_MISUSE] means that the this routine was called inappropriately.
4254** Perhaps it was called on a [prepared statement] that has
4255** already been [sqlite3_finalize | finalized] or on one that had
4256** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
4257** be the case that the same database connection is being used by two or
4258** more threads at the same moment in time.
4259**
4260** For all versions of SQLite up to and including 3.6.23.1, a call to
4261** [sqlite3_reset()] was required after sqlite3_step() returned anything
4262** other than [SQLITE_ROW] before any subsequent invocation of
4263** sqlite3_step(). Failure to reset the prepared statement using
4264** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
4265** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1],
4266** sqlite3_step() began
4267** calling [sqlite3_reset()] automatically in this circumstance rather
4268** than returning [SQLITE_MISUSE]. This is not considered a compatibility
4269** break because any application that ever receives an SQLITE_MISUSE error
4270** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
4271** can be used to restore the legacy behavior.
4272**
4273** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
4274** API always returns a generic error code, [SQLITE_ERROR], following any
4275** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
4276** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
4277** specific [error codes] that better describes the error.
4278** We admit that this is a goofy design. The problem has been fixed
4279** with the "v2" interface. If you prepare all of your SQL statements
4280** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
4281** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
4282** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
4283** then the more specific [error codes] are returned directly
4284** by sqlite3_step(). The use of the "vX" interfaces is recommended.
4285*/
4286SQLITE_API int sqlite3_step(sqlite3_stmt*);
4287
4288/*
4289** CAPI3REF: Number of columns in a result set
4290** METHOD: sqlite3_stmt
4291**
4292** ^The sqlite3_data_count(P) interface returns the number of columns in the
4293** current row of the result set of [prepared statement] P.
4294** ^If prepared statement P does not have results ready to return
4295** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
4296** interfaces) then sqlite3_data_count(P) returns 0.
4297** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
4298** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
4299** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
4300** will return non-zero if previous call to [sqlite3_step](P) returned
4301** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
4302** where it always returns zero since each step of that multi-step
4303** pragma returns 0 columns of data.
4304**
4305** See also: [sqlite3_column_count()]
4306*/
4307SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
4308
4309/*
4310** CAPI3REF: Fundamental Datatypes
4311** KEYWORDS: SQLITE_TEXT
4312**
4313** ^(Every value in SQLite has one of five fundamental datatypes:
4314**
4315** <ul>
4316** <li> 64-bit signed integer
4317** <li> 64-bit IEEE floating point number
4318** <li> string
4319** <li> BLOB
4320** <li> NULL
4321** </ul>)^
4322**
4323** These constants are codes for each of those types.
4324**
4325** Note that the SQLITE_TEXT constant was also used in SQLite version 2
4326** for a completely different meaning. Software that links against both
4327** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
4328** SQLITE_TEXT.
4329*/
4330#define SQLITE_INTEGER 1
4331#define SQLITE_FLOAT 2
4332#define SQLITE_BLOB 4
4333#define SQLITE_NULL 5
4334#ifdef SQLITE_TEXT
4335# undef SQLITE_TEXT
4336#else
4337# define SQLITE_TEXT 3
4338#endif
4339#define SQLITE3_TEXT 3
4340
4341/*
4342** CAPI3REF: Result Values From A Query
4343** KEYWORDS: {column access functions}
4344** METHOD: sqlite3_stmt
4345**
4346** <b>Summary:</b>
4347** <blockquote><table border=0 cellpadding=0 cellspacing=0>
4348** <tr><td><b>sqlite3_column_blob</b><td>&rarr;<td>BLOB result
4349** <tr><td><b>sqlite3_column_double</b><td>&rarr;<td>REAL result
4350** <tr><td><b>sqlite3_column_int</b><td>&rarr;<td>32-bit INTEGER result
4351** <tr><td><b>sqlite3_column_int64</b><td>&rarr;<td>64-bit INTEGER result
4352** <tr><td><b>sqlite3_column_text</b><td>&rarr;<td>UTF-8 TEXT result
4353** <tr><td><b>sqlite3_column_text16</b><td>&rarr;<td>UTF-16 TEXT result
4354** <tr><td><b>sqlite3_column_value</b><td>&rarr;<td>The result as an
4355** [sqlite3_value|unprotected sqlite3_value] object.
4356** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
4357** <tr><td><b>sqlite3_column_bytes</b><td>&rarr;<td>Size of a BLOB
4358** or a UTF-8 TEXT result in bytes
4359** <tr><td><b>sqlite3_column_bytes16&nbsp;&nbsp;</b>
4360** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
4361** TEXT in bytes
4362** <tr><td><b>sqlite3_column_type</b><td>&rarr;<td>Default
4363** datatype of the result
4364** </table></blockquote>
4365**
4366** <b>Details:</b>
4367**
4368** ^These routines return information about a single column of the current
4369** result row of a query. ^In every case the first argument is a pointer
4370** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
4371** that was returned from [sqlite3_prepare_v2()] or one of its variants)
4372** and the second argument is the index of the column for which information
4373** should be returned. ^The leftmost column of the result set has the index 0.
4374** ^The number of columns in the result can be determined using
4375** [sqlite3_column_count()].
4376**
4377** If the SQL statement does not currently point to a valid row, or if the
4378** column index is out of range, the result is undefined.
4379** These routines may only be called when the most recent call to
4380** [sqlite3_step()] has returned [SQLITE_ROW] and neither
4381** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
4382** If any of these routines are called after [sqlite3_reset()] or
4383** [sqlite3_finalize()] or after [sqlite3_step()] has returned
4384** something other than [SQLITE_ROW], the results are undefined.
4385** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
4386** are called from a different thread while any of these routines
4387** are pending, then the results are undefined.
4388**
4389** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
4390** each return the value of a result column in a specific data format. If
4391** the result column is not initially in the requested format (for example,
4392** if the query returns an integer but the sqlite3_column_text() interface
4393** is used to extract the value) then an automatic type conversion is performed.
4394**
4395** ^The sqlite3_column_type() routine returns the
4396** [SQLITE_INTEGER | datatype code] for the initial data type
4397** of the result column. ^The returned value is one of [SQLITE_INTEGER],
4398** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
4399** The return value of sqlite3_column_type() can be used to decide which
4400** of the first six interface should be used to extract the column value.
4401** The value returned by sqlite3_column_type() is only meaningful if no
4402** automatic type conversions have occurred for the value in question.
4403** After a type conversion, the result of calling sqlite3_column_type()
4404** is undefined, though harmless. Future
4405** versions of SQLite may change the behavior of sqlite3_column_type()
4406** following a type conversion.
4407**
4408** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
4409** or sqlite3_column_bytes16() interfaces can be used to determine the size
4410** of that BLOB or string.
4411**
4412** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
4413** routine returns the number of bytes in that BLOB or string.
4414** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
4415** the string to UTF-8 and then returns the number of bytes.
4416** ^If the result is a numeric value then sqlite3_column_bytes() uses
4417** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
4418** the number of bytes in that string.
4419** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
4420**
4421** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
4422** routine returns the number of bytes in that BLOB or string.
4423** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
4424** the string to UTF-16 and then returns the number of bytes.
4425** ^If the result is a numeric value then sqlite3_column_bytes16() uses
4426** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
4427** the number of bytes in that string.
4428** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
4429**
4430** ^The values returned by [sqlite3_column_bytes()] and
4431** [sqlite3_column_bytes16()] do not include the zero terminators at the end
4432** of the string. ^For clarity: the values returned by
4433** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
4434** bytes in the string, not the number of characters.
4435**
4436** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
4437** even empty strings, are always zero-terminated. ^The return
4438** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
4439**
4440** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
4441** [unprotected sqlite3_value] object. In a multithreaded environment,
4442** an unprotected sqlite3_value object may only be used safely with
4443** [sqlite3_bind_value()] and [sqlite3_result_value()].
4444** If the [unprotected sqlite3_value] object returned by
4445** [sqlite3_column_value()] is used in any other way, including calls
4446** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
4447** or [sqlite3_value_bytes()], the behavior is not threadsafe.
4448** Hence, the sqlite3_column_value() interface
4449** is normally only useful within the implementation of
4450** [application-defined SQL functions] or [virtual tables], not within
4451** top-level application code.
4452**
4453** The these routines may attempt to convert the datatype of the result.
4454** ^For example, if the internal representation is FLOAT and a text result
4455** is requested, [sqlite3_snprintf()] is used internally to perform the
4456** conversion automatically. ^(The following table details the conversions
4457** that are applied:
4458**
4459** <blockquote>
4460** <table border="1">
4461** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
4462**
4463** <tr><td> NULL <td> INTEGER <td> Result is 0
4464** <tr><td> NULL <td> FLOAT <td> Result is 0.0
4465** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer
4466** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer
4467** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
4468** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
4469** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
4470** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER
4471** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
4472** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB
4473** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER
4474** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL
4475** <tr><td> TEXT <td> BLOB <td> No change
4476** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER
4477** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL
4478** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
4479** </table>
4480** </blockquote>)^
4481**
4482** Note that when type conversions occur, pointers returned by prior
4483** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
4484** sqlite3_column_text16() may be invalidated.
4485** Type conversions and pointer invalidations might occur
4486** in the following cases:
4487**
4488** <ul>
4489** <li> The initial content is a BLOB and sqlite3_column_text() or
4490** sqlite3_column_text16() is called. A zero-terminator might
4491** need to be added to the string.</li>
4492** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
4493** sqlite3_column_text16() is called. The content must be converted
4494** to UTF-16.</li>
4495** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
4496** sqlite3_column_text() is called. The content must be converted
4497** to UTF-8.</li>
4498** </ul>
4499**
4500** ^Conversions between UTF-16be and UTF-16le are always done in place and do
4501** not invalidate a prior pointer, though of course the content of the buffer
4502** that the prior pointer references will have been modified. Other kinds
4503** of conversion are done in place when it is possible, but sometimes they
4504** are not possible and in those cases prior pointers are invalidated.
4505**
4506** The safest policy is to invoke these routines
4507** in one of the following ways:
4508**
4509** <ul>
4510** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
4511** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
4512** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
4513** </ul>
4514**
4515** In other words, you should call sqlite3_column_text(),
4516** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
4517** into the desired format, then invoke sqlite3_column_bytes() or
4518** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
4519** to sqlite3_column_text() or sqlite3_column_blob() with calls to
4520** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
4521** with calls to sqlite3_column_bytes().
4522**
4523** ^The pointers returned are valid until a type conversion occurs as
4524** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
4525** [sqlite3_finalize()] is called. ^The memory space used to hold strings
4526** and BLOBs is freed automatically. Do not pass the pointers returned
4527** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
4528** [sqlite3_free()].
4529**
4530** ^(If a memory allocation error occurs during the evaluation of any
4531** of these routines, a default value is returned. The default value
4532** is either the integer 0, the floating point number 0.0, or a NULL
4533** pointer. Subsequent calls to [sqlite3_errcode()] will return
4534** [SQLITE_NOMEM].)^
4535*/
4536SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
4537SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
4538SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
4539SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
4540SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
4541SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
4542SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
4543SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
4544SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
4545SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
4546
4547/*
4548** CAPI3REF: Destroy A Prepared Statement Object
4549** DESTRUCTOR: sqlite3_stmt
4550**
4551** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4552** ^If the most recent evaluation of the statement encountered no errors
4553** or if the statement is never been evaluated, then sqlite3_finalize() returns
4554** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
4555** sqlite3_finalize(S) returns the appropriate [error code] or
4556** [extended error code].
4557**
4558** ^The sqlite3_finalize(S) routine can be called at any point during
4559** the life cycle of [prepared statement] S:
4560** before statement S is ever evaluated, after
4561** one or more calls to [sqlite3_reset()], or after any call
4562** to [sqlite3_step()] regardless of whether or not the statement has
4563** completed execution.
4564**
4565** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4566**
4567** The application must finalize every [prepared statement] in order to avoid
4568** resource leaks. It is a grievous error for the application to try to use
4569** a prepared statement after it has been finalized. Any use of a prepared
4570** statement after it has been finalized can result in undefined and
4571** undesirable behavior such as segfaults and heap corruption.
4572*/
4573SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
4574
4575/*
4576** CAPI3REF: Reset A Prepared Statement Object
4577** METHOD: sqlite3_stmt
4578**
4579** The sqlite3_reset() function is called to reset a [prepared statement]
4580** object back to its initial state, ready to be re-executed.
4581** ^Any SQL statement variables that had values bound to them using
4582** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4583** Use [sqlite3_clear_bindings()] to reset the bindings.
4584**
4585** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4586** back to the beginning of its program.
4587**
4588** ^If the most recent call to [sqlite3_step(S)] for the
4589** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4590** or if [sqlite3_step(S)] has never before been called on S,
4591** then [sqlite3_reset(S)] returns [SQLITE_OK].
4592**
4593** ^If the most recent call to [sqlite3_step(S)] for the
4594** [prepared statement] S indicated an error, then
4595** [sqlite3_reset(S)] returns an appropriate [error code].
4596**
4597** ^The [sqlite3_reset(S)] interface does not change the values
4598** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4599*/
4600SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
4601
4602/*
4603** CAPI3REF: Create Or Redefine SQL Functions
4604** KEYWORDS: {function creation routines}
4605** KEYWORDS: {application-defined SQL function}
4606** KEYWORDS: {application-defined SQL functions}
4607** METHOD: sqlite3
4608**
4609** ^These functions (collectively known as "function creation routines")
4610** are used to add SQL functions or aggregates or to redefine the behavior
4611** of existing SQL functions or aggregates. The only differences between
4612** these routines are the text encoding expected for
4613** the second parameter (the name of the function being created)
4614** and the presence or absence of a destructor callback for
4615** the application data pointer.
4616**
4617** ^The first parameter is the [database connection] to which the SQL
4618** function is to be added. ^If an application uses more than one database
4619** connection then application-defined SQL functions must be added
4620** to each database connection separately.
4621**
4622** ^The second parameter is the name of the SQL function to be created or
4623** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
4624** representation, exclusive of the zero-terminator. ^Note that the name
4625** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4626** ^Any attempt to create a function with a longer name
4627** will result in [SQLITE_MISUSE] being returned.
4628**
4629** ^The third parameter (nArg)
4630** is the number of arguments that the SQL function or
4631** aggregate takes. ^If this parameter is -1, then the SQL function or
4632** aggregate may take any number of arguments between 0 and the limit
4633** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
4634** parameter is less than -1 or greater than 127 then the behavior is
4635** undefined.
4636**
4637** ^The fourth parameter, eTextRep, specifies what
4638** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4639** its parameters. The application should set this parameter to
4640** [SQLITE_UTF16LE] if the function implementation invokes
4641** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4642** implementation invokes [sqlite3_value_text16be()] on an input, or
4643** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4644** otherwise. ^The same SQL function may be registered multiple times using
4645** different preferred text encodings, with different implementations for
4646** each encoding.
4647** ^When multiple implementations of the same function are available, SQLite
4648** will pick the one that involves the least amount of data conversion.
4649**
4650** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4651** to signal that the function will always return the same result given
4652** the same inputs within a single SQL statement. Most SQL functions are
4653** deterministic. The built-in [random()] SQL function is an example of a
4654** function that is not deterministic. The SQLite query planner is able to
4655** perform additional optimizations on deterministic functions, so use
4656** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4657**
4658** ^(The fifth parameter is an arbitrary pointer. The implementation of the
4659** function can gain access to this pointer using [sqlite3_user_data()].)^
4660**
4661** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
4662** pointers to C-language functions that implement the SQL function or
4663** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4664** callback only; NULL pointers must be passed as the xStep and xFinal
4665** parameters. ^An aggregate SQL function requires an implementation of xStep
4666** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4667** SQL function or aggregate, pass NULL pointers for all three function
4668** callbacks.
4669**
4670** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
4671** then it is destructor for the application data pointer.
4672** The destructor is invoked when the function is deleted, either by being
4673** overloaded or when the database connection closes.)^
4674** ^The destructor is also invoked if the call to
4675** sqlite3_create_function_v2() fails.
4676** ^When the destructor callback of the tenth parameter is invoked, it
4677** is passed a single argument which is a copy of the application data
4678** pointer which was the fifth parameter to sqlite3_create_function_v2().
4679**
4680** ^It is permitted to register multiple implementations of the same
4681** functions with the same name but with either differing numbers of
4682** arguments or differing preferred text encodings. ^SQLite will use
4683** the implementation that most closely matches the way in which the
4684** SQL function is used. ^A function implementation with a non-negative
4685** nArg parameter is a better match than a function implementation with
4686** a negative nArg. ^A function where the preferred text encoding
4687** matches the database encoding is a better
4688** match than a function where the encoding is different.
4689** ^A function where the encoding difference is between UTF16le and UTF16be
4690** is a closer match than a function where the encoding difference is
4691** between UTF8 and UTF16.
4692**
4693** ^Built-in functions may be overloaded by new application-defined functions.
4694**
4695** ^An application-defined function is permitted to call other
4696** SQLite interfaces. However, such calls must not
4697** close the database connection nor finalize or reset the prepared
4698** statement in which the function is running.
4699*/
4700SQLITE_API int sqlite3_create_function(
4701 sqlite3 *db,
4702 const char *zFunctionName,
4703 int nArg,
4704 int eTextRep,
4705 void *pApp,
4706 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4707 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4708 void (*xFinal)(sqlite3_context*)
4709);
4710SQLITE_API int sqlite3_create_function16(
4711 sqlite3 *db,
4712 const void *zFunctionName,
4713 int nArg,
4714 int eTextRep,
4715 void *pApp,
4716 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4717 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4718 void (*xFinal)(sqlite3_context*)
4719);
4720SQLITE_API int sqlite3_create_function_v2(
4721 sqlite3 *db,
4722 const char *zFunctionName,
4723 int nArg,
4724 int eTextRep,
4725 void *pApp,
4726 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4727 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4728 void (*xFinal)(sqlite3_context*),
4729 void(*xDestroy)(void*)
4730);
4731
4732/*
4733** CAPI3REF: Text Encodings
4734**
4735** These constant define integer codes that represent the various
4736** text encodings supported by SQLite.
4737*/
4738#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */
4739#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */
4740#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */
4741#define SQLITE_UTF16 4 /* Use native byte order */
4742#define SQLITE_ANY 5 /* Deprecated */
4743#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
4744
4745/*
4746** CAPI3REF: Function Flags
4747**
4748** These constants may be ORed together with the
4749** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4750** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4751** [sqlite3_create_function_v2()].
4752*/
4753#define SQLITE_DETERMINISTIC 0x800
4754
4755/*
4756** CAPI3REF: Deprecated Functions
4757** DEPRECATED
4758**
4759** These functions are [deprecated]. In order to maintain
4760** backwards compatibility with older code, these functions continue
4761** to be supported. However, new applications should avoid
4762** the use of these functions. To encourage programmers to avoid
4763** these functions, we will not explain what they do.
4764*/
4765#ifndef SQLITE_OMIT_DEPRECATED
4766SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
4767SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
4768SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4769SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
4770SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
4771SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4772 void*,sqlite3_int64);
4773#endif
4774
4775/*
4776** CAPI3REF: Obtaining SQL Values
4777** METHOD: sqlite3_value
4778**
4779** <b>Summary:</b>
4780** <blockquote><table border=0 cellpadding=0 cellspacing=0>
4781** <tr><td><b>sqlite3_value_blob</b><td>&rarr;<td>BLOB value
4782** <tr><td><b>sqlite3_value_double</b><td>&rarr;<td>REAL value
4783** <tr><td><b>sqlite3_value_int</b><td>&rarr;<td>32-bit INTEGER value
4784** <tr><td><b>sqlite3_value_int64</b><td>&rarr;<td>64-bit INTEGER value
4785** <tr><td><b>sqlite3_value_pointer</b><td>&rarr;<td>Pointer value
4786** <tr><td><b>sqlite3_value_text</b><td>&rarr;<td>UTF-8 TEXT value
4787** <tr><td><b>sqlite3_value_text16</b><td>&rarr;<td>UTF-16 TEXT value in
4788** the native byteorder
4789** <tr><td><b>sqlite3_value_text16be</b><td>&rarr;<td>UTF-16be TEXT value
4790** <tr><td><b>sqlite3_value_text16le</b><td>&rarr;<td>UTF-16le TEXT value
4791** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
4792** <tr><td><b>sqlite3_value_bytes</b><td>&rarr;<td>Size of a BLOB
4793** or a UTF-8 TEXT in bytes
4794** <tr><td><b>sqlite3_value_bytes16&nbsp;&nbsp;</b>
4795** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
4796** TEXT in bytes
4797** <tr><td><b>sqlite3_value_type</b><td>&rarr;<td>Default
4798** datatype of the value
4799** <tr><td><b>sqlite3_value_numeric_type&nbsp;&nbsp;</b>
4800** <td>&rarr;&nbsp;&nbsp;<td>Best numeric datatype of the value
4801** <tr><td><b>sqlite3_value_nochange&nbsp;&nbsp;</b>
4802** <td>&rarr;&nbsp;&nbsp;<td>True if the column is unchanged in an UPDATE
4803** against a virtual table.
4804** </table></blockquote>
4805**
4806** <b>Details:</b>
4807**
4808** These routines extract type, size, and content information from
4809** [protected sqlite3_value] objects. Protected sqlite3_value objects
4810** are used to pass parameter information into implementation of
4811** [application-defined SQL functions] and [virtual tables].
4812**
4813** These routines work only with [protected sqlite3_value] objects.
4814** Any attempt to use these routines on an [unprotected sqlite3_value]
4815** is not threadsafe.
4816**
4817** ^These routines work just like the corresponding [column access functions]
4818** except that these routines take a single [protected sqlite3_value] object
4819** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4820**
4821** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4822** in the native byte-order of the host machine. ^The
4823** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4824** extract UTF-16 strings as big-endian and little-endian respectively.
4825**
4826** ^If [sqlite3_value] object V was initialized
4827** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
4828** and if X and Y are strings that compare equal according to strcmp(X,Y),
4829** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise,
4830** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
4831** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
4832**
4833** ^(The sqlite3_value_type(V) interface returns the
4834** [SQLITE_INTEGER | datatype code] for the initial datatype of the
4835** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
4836** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
4837** Other interfaces might change the datatype for an sqlite3_value object.
4838** For example, if the datatype is initially SQLITE_INTEGER and
4839** sqlite3_value_text(V) is called to extract a text value for that
4840** integer, then subsequent calls to sqlite3_value_type(V) might return
4841** SQLITE_TEXT. Whether or not a persistent internal datatype conversion
4842** occurs is undefined and may change from one release of SQLite to the next.
4843**
4844** ^(The sqlite3_value_numeric_type() interface attempts to apply
4845** numeric affinity to the value. This means that an attempt is
4846** made to convert the value to an integer or floating point. If
4847** such a conversion is possible without loss of information (in other
4848** words, if the value is a string that looks like a number)
4849** then the conversion is performed. Otherwise no conversion occurs.
4850** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4851**
4852** ^Within the [xUpdate] method of a [virtual table], the
4853** sqlite3_value_nochange(X) interface returns true if and only if
4854** the column corresponding to X is unchanged by the UPDATE operation
4855** that the xUpdate method call was invoked to implement and if
4856** and the prior [xColumn] method call that was invoked to extracted
4857** the value for that column returned without setting a result (probably
4858** because it queried [sqlite3_vtab_nochange()] and found that the column
4859** was unchanging). ^Within an [xUpdate] method, any value for which
4860** sqlite3_value_nochange(X) is true will in all other respects appear
4861** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other
4862** than within an [xUpdate] method call for an UPDATE statement, then
4863** the return value is arbitrary and meaningless.
4864**
4865** Please pay particular attention to the fact that the pointer returned
4866** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4867** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4868** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4869** or [sqlite3_value_text16()].
4870**
4871** These routines must be called from the same thread as
4872** the SQL function that supplied the [sqlite3_value*] parameters.
4873*/
4874SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
4875SQLITE_API double sqlite3_value_double(sqlite3_value*);
4876SQLITE_API int sqlite3_value_int(sqlite3_value*);
4877SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
4878SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
4879SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
4880SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
4881SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
4882SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
4883SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
4884SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
4885SQLITE_API int sqlite3_value_type(sqlite3_value*);
4886SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
4887SQLITE_API int sqlite3_value_nochange(sqlite3_value*);
4888
4889/*
4890** CAPI3REF: Finding The Subtype Of SQL Values
4891** METHOD: sqlite3_value
4892**
4893** The sqlite3_value_subtype(V) function returns the subtype for
4894** an [application-defined SQL function] argument V. The subtype
4895** information can be used to pass a limited amount of context from
4896** one SQL function to another. Use the [sqlite3_result_subtype()]
4897** routine to set the subtype for the return value of an SQL function.
4898*/
4899SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
4900
4901/*
4902** CAPI3REF: Copy And Free SQL Values
4903** METHOD: sqlite3_value
4904**
4905** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
4906** object D and returns a pointer to that copy. ^The [sqlite3_value] returned
4907** is a [protected sqlite3_value] object even if the input is not.
4908** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
4909** memory allocation fails.
4910**
4911** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
4912** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer
4913** then sqlite3_value_free(V) is a harmless no-op.
4914*/
4915SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
4916SQLITE_API void sqlite3_value_free(sqlite3_value*);
4917
4918/*
4919** CAPI3REF: Obtain Aggregate Function Context
4920** METHOD: sqlite3_context
4921**
4922** Implementations of aggregate SQL functions use this
4923** routine to allocate memory for storing their state.
4924**
4925** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4926** for a particular aggregate function, SQLite
4927** allocates N of memory, zeroes out that memory, and returns a pointer
4928** to the new memory. ^On second and subsequent calls to
4929** sqlite3_aggregate_context() for the same aggregate function instance,
4930** the same buffer is returned. Sqlite3_aggregate_context() is normally
4931** called once for each invocation of the xStep callback and then one
4932** last time when the xFinal callback is invoked. ^(When no rows match
4933** an aggregate query, the xStep() callback of the aggregate function
4934** implementation is never called and xFinal() is called exactly once.
4935** In those cases, sqlite3_aggregate_context() might be called for the
4936** first time from within xFinal().)^
4937**
4938** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
4939** when first called if N is less than or equal to zero or if a memory
4940** allocate error occurs.
4941**
4942** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4943** determined by the N parameter on first successful call. Changing the
4944** value of N in subsequent call to sqlite3_aggregate_context() within
4945** the same aggregate function instance will not resize the memory
4946** allocation.)^ Within the xFinal callback, it is customary to set
4947** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
4948** pointless memory allocations occur.
4949**
4950** ^SQLite automatically frees the memory allocated by
4951** sqlite3_aggregate_context() when the aggregate query concludes.
4952**
4953** The first parameter must be a copy of the
4954** [sqlite3_context | SQL function context] that is the first parameter
4955** to the xStep or xFinal callback routine that implements the aggregate
4956** function.
4957**
4958** This routine must be called from the same thread in which
4959** the aggregate SQL function is running.
4960*/
4961SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4962
4963/*
4964** CAPI3REF: User Data For Functions
4965** METHOD: sqlite3_context
4966**
4967** ^The sqlite3_user_data() interface returns a copy of
4968** the pointer that was the pUserData parameter (the 5th parameter)
4969** of the [sqlite3_create_function()]
4970** and [sqlite3_create_function16()] routines that originally
4971** registered the application defined function.
4972**
4973** This routine must be called from the same thread in which
4974** the application-defined function is running.
4975*/
4976SQLITE_API void *sqlite3_user_data(sqlite3_context*);
4977
4978/*
4979** CAPI3REF: Database Connection For Functions
4980** METHOD: sqlite3_context
4981**
4982** ^The sqlite3_context_db_handle() interface returns a copy of
4983** the pointer to the [database connection] (the 1st parameter)
4984** of the [sqlite3_create_function()]
4985** and [sqlite3_create_function16()] routines that originally
4986** registered the application defined function.
4987*/
4988SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
4989
4990/*
4991** CAPI3REF: Function Auxiliary Data
4992** METHOD: sqlite3_context
4993**
4994** These functions may be used by (non-aggregate) SQL functions to
4995** associate metadata with argument values. If the same value is passed to
4996** multiple invocations of the same SQL function during query execution, under
4997** some circumstances the associated metadata may be preserved. An example
4998** of where this might be useful is in a regular-expression matching
4999** function. The compiled version of the regular expression can be stored as
5000** metadata associated with the pattern string.
5001** Then as long as the pattern string remains the same,
5002** the compiled regular expression can be reused on multiple
5003** invocations of the same function.
5004**
5005** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata
5006** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
5007** value to the application-defined function. ^N is zero for the left-most
5008** function argument. ^If there is no metadata
5009** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
5010** returns a NULL pointer.
5011**
5012** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
5013** argument of the application-defined function. ^Subsequent
5014** calls to sqlite3_get_auxdata(C,N) return P from the most recent
5015** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
5016** NULL if the metadata has been discarded.
5017** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
5018** SQLite will invoke the destructor function X with parameter P exactly
5019** once, when the metadata is discarded.
5020** SQLite is free to discard the metadata at any time, including: <ul>
5021** <li> ^(when the corresponding function parameter changes)^, or
5022** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
5023** SQL statement)^, or
5024** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
5025** parameter)^, or
5026** <li> ^(during the original sqlite3_set_auxdata() call when a memory
5027** allocation error occurs.)^ </ul>
5028**
5029** Note the last bullet in particular. The destructor X in
5030** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
5031** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
5032** should be called near the end of the function implementation and the
5033** function implementation should not make any use of P after
5034** sqlite3_set_auxdata() has been called.
5035**
5036** ^(In practice, metadata is preserved between function calls for
5037** function parameters that are compile-time constants, including literal
5038** values and [parameters] and expressions composed from the same.)^
5039**
5040** The value of the N parameter to these interfaces should be non-negative.
5041** Future enhancements may make use of negative N values to define new
5042** kinds of function caching behavior.
5043**
5044** These routines must be called from the same thread in which
5045** the SQL function is running.
5046*/
5047SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
5048SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
5049
5050
5051/*
5052** CAPI3REF: Constants Defining Special Destructor Behavior
5053**
5054** These are special values for the destructor that is passed in as the
5055** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
5056** argument is SQLITE_STATIC, it means that the content pointer is constant
5057** and will never change. It does not need to be destroyed. ^The
5058** SQLITE_TRANSIENT value means that the content will likely change in
5059** the near future and that SQLite should make its own private copy of
5060** the content before returning.
5061**
5062** The typedef is necessary to work around problems in certain
5063** C++ compilers.
5064*/
5065typedef void (*sqlite3_destructor_type)(void*);
5066#define SQLITE_STATIC ((sqlite3_destructor_type)0)
5067#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
5068
5069/*
5070** CAPI3REF: Setting The Result Of An SQL Function
5071** METHOD: sqlite3_context
5072**
5073** These routines are used by the xFunc or xFinal callbacks that
5074** implement SQL functions and aggregates. See
5075** [sqlite3_create_function()] and [sqlite3_create_function16()]
5076** for additional information.
5077**
5078** These functions work very much like the [parameter binding] family of
5079** functions used to bind values to host parameters in prepared statements.
5080** Refer to the [SQL parameter] documentation for additional information.
5081**
5082** ^The sqlite3_result_blob() interface sets the result from
5083** an application-defined function to be the BLOB whose content is pointed
5084** to by the second parameter and which is N bytes long where N is the
5085** third parameter.
5086**
5087** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
5088** interfaces set the result of the application-defined function to be
5089** a BLOB containing all zero bytes and N bytes in size.
5090**
5091** ^The sqlite3_result_double() interface sets the result from
5092** an application-defined function to be a floating point value specified
5093** by its 2nd argument.
5094**
5095** ^The sqlite3_result_error() and sqlite3_result_error16() functions
5096** cause the implemented SQL function to throw an exception.
5097** ^SQLite uses the string pointed to by the
5098** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
5099** as the text of an error message. ^SQLite interprets the error
5100** message string from sqlite3_result_error() as UTF-8. ^SQLite
5101** interprets the string from sqlite3_result_error16() as UTF-16 in native
5102** byte order. ^If the third parameter to sqlite3_result_error()
5103** or sqlite3_result_error16() is negative then SQLite takes as the error
5104** message all text up through the first zero character.
5105** ^If the third parameter to sqlite3_result_error() or
5106** sqlite3_result_error16() is non-negative then SQLite takes that many
5107** bytes (not characters) from the 2nd parameter as the error message.
5108** ^The sqlite3_result_error() and sqlite3_result_error16()
5109** routines make a private copy of the error message text before
5110** they return. Hence, the calling function can deallocate or
5111** modify the text after they return without harm.
5112** ^The sqlite3_result_error_code() function changes the error code
5113** returned by SQLite as a result of an error in a function. ^By default,
5114** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
5115** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
5116**
5117** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
5118** error indicating that a string or BLOB is too long to represent.
5119**
5120** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
5121** error indicating that a memory allocation failed.
5122**
5123** ^The sqlite3_result_int() interface sets the return value
5124** of the application-defined function to be the 32-bit signed integer
5125** value given in the 2nd argument.
5126** ^The sqlite3_result_int64() interface sets the return value
5127** of the application-defined function to be the 64-bit signed integer
5128** value given in the 2nd argument.
5129**
5130** ^The sqlite3_result_null() interface sets the return value
5131** of the application-defined function to be NULL.
5132**
5133** ^The sqlite3_result_text(), sqlite3_result_text16(),
5134** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
5135** set the return value of the application-defined function to be
5136** a text string which is represented as UTF-8, UTF-16 native byte order,
5137** UTF-16 little endian, or UTF-16 big endian, respectively.
5138** ^The sqlite3_result_text64() interface sets the return value of an
5139** application-defined function to be a text string in an encoding
5140** specified by the fifth (and last) parameter, which must be one
5141** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
5142** ^SQLite takes the text result from the application from
5143** the 2nd parameter of the sqlite3_result_text* interfaces.
5144** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5145** is negative, then SQLite takes result text from the 2nd parameter
5146** through the first zero character.
5147** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5148** is non-negative, then as many bytes (not characters) of the text
5149** pointed to by the 2nd parameter are taken as the application-defined
5150** function result. If the 3rd parameter is non-negative, then it
5151** must be the byte offset into the string where the NUL terminator would
5152** appear if the string where NUL terminated. If any NUL characters occur
5153** in the string at a byte offset that is less than the value of the 3rd
5154** parameter, then the resulting string will contain embedded NULs and the
5155** result of expressions operating on strings with embedded NULs is undefined.
5156** ^If the 4th parameter to the sqlite3_result_text* interfaces
5157** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
5158** function as the destructor on the text or BLOB result when it has
5159** finished using that result.
5160** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
5161** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
5162** assumes that the text or BLOB result is in constant space and does not
5163** copy the content of the parameter nor call a destructor on the content
5164** when it has finished using that result.
5165** ^If the 4th parameter to the sqlite3_result_text* interfaces
5166** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
5167** then SQLite makes a copy of the result into space obtained
5168** from [sqlite3_malloc()] before it returns.
5169**
5170** ^The sqlite3_result_value() interface sets the result of
5171** the application-defined function to be a copy of the
5172** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
5173** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
5174** so that the [sqlite3_value] specified in the parameter may change or
5175** be deallocated after sqlite3_result_value() returns without harm.
5176** ^A [protected sqlite3_value] object may always be used where an
5177** [unprotected sqlite3_value] object is required, so either
5178** kind of [sqlite3_value] object can be used with this interface.
5179**
5180** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
5181** SQL NULL value, just like [sqlite3_result_null(C)], except that it
5182** also associates the host-language pointer P or type T with that
5183** NULL value such that the pointer can be retrieved within an
5184** [application-defined SQL function] using [sqlite3_value_pointer()].
5185** ^If the D parameter is not NULL, then it is a pointer to a destructor
5186** for the P parameter. ^SQLite invokes D with P as its only argument
5187** when SQLite is finished with P. The T parameter should be a static
5188** string and preferably a string literal. The sqlite3_result_pointer()
5189** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5190**
5191** If these routines are called from within the different thread
5192** than the one containing the application-defined function that received
5193** the [sqlite3_context] pointer, the results are undefined.
5194*/
5195SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
5196SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
5197 sqlite3_uint64,void(*)(void*));
5198SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
5199SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
5200SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
5201SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
5202SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
5203SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
5204SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
5205SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
5206SQLITE_API void sqlite3_result_null(sqlite3_context*);
5207SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
5208SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
5209 void(*)(void*), unsigned char encoding);
5210SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
5211SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
5212SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
5213SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
5214SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
5215SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
5216SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
5217
5218
5219/*
5220** CAPI3REF: Setting The Subtype Of An SQL Function
5221** METHOD: sqlite3_context
5222**
5223** The sqlite3_result_subtype(C,T) function causes the subtype of
5224** the result from the [application-defined SQL function] with
5225** [sqlite3_context] C to be the value T. Only the lower 8 bits
5226** of the subtype T are preserved in current versions of SQLite;
5227** higher order bits are discarded.
5228** The number of subtype bytes preserved by SQLite might increase
5229** in future releases of SQLite.
5230*/
5231SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
5232
5233/*
5234** CAPI3REF: Define New Collating Sequences
5235** METHOD: sqlite3
5236**
5237** ^These functions add, remove, or modify a [collation] associated
5238** with the [database connection] specified as the first argument.
5239**
5240** ^The name of the collation is a UTF-8 string
5241** for sqlite3_create_collation() and sqlite3_create_collation_v2()
5242** and a UTF-16 string in native byte order for sqlite3_create_collation16().
5243** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
5244** considered to be the same name.
5245**
5246** ^(The third argument (eTextRep) must be one of the constants:
5247** <ul>
5248** <li> [SQLITE_UTF8],
5249** <li> [SQLITE_UTF16LE],
5250** <li> [SQLITE_UTF16BE],
5251** <li> [SQLITE_UTF16], or
5252** <li> [SQLITE_UTF16_ALIGNED].
5253** </ul>)^
5254** ^The eTextRep argument determines the encoding of strings passed
5255** to the collating function callback, xCallback.
5256** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
5257** force strings to be UTF16 with native byte order.
5258** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
5259** on an even byte address.
5260**
5261** ^The fourth argument, pArg, is an application data pointer that is passed
5262** through as the first argument to the collating function callback.
5263**
5264** ^The fifth argument, xCallback, is a pointer to the collating function.
5265** ^Multiple collating functions can be registered using the same name but
5266** with different eTextRep parameters and SQLite will use whichever
5267** function requires the least amount of data transformation.
5268** ^If the xCallback argument is NULL then the collating function is
5269** deleted. ^When all collating functions having the same name are deleted,
5270** that collation is no longer usable.
5271**
5272** ^The collating function callback is invoked with a copy of the pArg
5273** application data pointer and with two strings in the encoding specified
5274** by the eTextRep argument. The collating function must return an
5275** integer that is negative, zero, or positive
5276** if the first string is less than, equal to, or greater than the second,
5277** respectively. A collating function must always return the same answer
5278** given the same inputs. If two or more collating functions are registered
5279** to the same collation name (using different eTextRep values) then all
5280** must give an equivalent answer when invoked with equivalent strings.
5281** The collating function must obey the following properties for all
5282** strings A, B, and C:
5283**
5284** <ol>
5285** <li> If A==B then B==A.
5286** <li> If A==B and B==C then A==C.
5287** <li> If A&lt;B THEN B&gt;A.
5288** <li> If A&lt;B and B&lt;C then A&lt;C.
5289** </ol>
5290**
5291** If a collating function fails any of the above constraints and that
5292** collating function is registered and used, then the behavior of SQLite
5293** is undefined.
5294**
5295** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
5296** with the addition that the xDestroy callback is invoked on pArg when
5297** the collating function is deleted.
5298** ^Collating functions are deleted when they are overridden by later
5299** calls to the collation creation functions or when the
5300** [database connection] is closed using [sqlite3_close()].
5301**
5302** ^The xDestroy callback is <u>not</u> called if the
5303** sqlite3_create_collation_v2() function fails. Applications that invoke
5304** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
5305** check the return code and dispose of the application data pointer
5306** themselves rather than expecting SQLite to deal with it for them.
5307** This is different from every other SQLite interface. The inconsistency
5308** is unfortunate but cannot be changed without breaking backwards
5309** compatibility.
5310**
5311** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
5312*/
5313SQLITE_API int sqlite3_create_collation(
5314 sqlite3*,
5315 const char *zName,
5316 int eTextRep,
5317 void *pArg,
5318 int(*xCompare)(void*,int,const void*,int,const void*)
5319);
5320SQLITE_API int sqlite3_create_collation_v2(
5321 sqlite3*,
5322 const char *zName,
5323 int eTextRep,
5324 void *pArg,
5325 int(*xCompare)(void*,int,const void*,int,const void*),
5326 void(*xDestroy)(void*)
5327);
5328SQLITE_API int sqlite3_create_collation16(
5329 sqlite3*,
5330 const void *zName,
5331 int eTextRep,
5332 void *pArg,
5333 int(*xCompare)(void*,int,const void*,int,const void*)
5334);
5335
5336/*
5337** CAPI3REF: Collation Needed Callbacks
5338** METHOD: sqlite3
5339**
5340** ^To avoid having to register all collation sequences before a database
5341** can be used, a single callback function may be registered with the
5342** [database connection] to be invoked whenever an undefined collation
5343** sequence is required.
5344**
5345** ^If the function is registered using the sqlite3_collation_needed() API,
5346** then it is passed the names of undefined collation sequences as strings
5347** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
5348** the names are passed as UTF-16 in machine native byte order.
5349** ^A call to either function replaces the existing collation-needed callback.
5350**
5351** ^(When the callback is invoked, the first argument passed is a copy
5352** of the second argument to sqlite3_collation_needed() or
5353** sqlite3_collation_needed16(). The second argument is the database
5354** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
5355** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
5356** sequence function required. The fourth parameter is the name of the
5357** required collation sequence.)^
5358**
5359** The callback function should register the desired collation using
5360** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
5361** [sqlite3_create_collation_v2()].
5362*/
5363SQLITE_API int sqlite3_collation_needed(
5364 sqlite3*,
5365 void*,
5366 void(*)(void*,sqlite3*,int eTextRep,const char*)
5367);
5368SQLITE_API int sqlite3_collation_needed16(
5369 sqlite3*,
5370 void*,
5371 void(*)(void*,sqlite3*,int eTextRep,const void*)
5372);
5373
5374#ifdef SQLITE_HAS_CODEC
5375/*
5376** Specify the key for an encrypted database. This routine should be
5377** called right after sqlite3_open().
5378**
5379** The code to implement this API is not available in the public release
5380** of SQLite.
5381*/
5382SQLITE_API int sqlite3_key(
5383 sqlite3 *db, /* Database to be rekeyed */
5384 const void *pKey, int nKey /* The key */
5385);
5386SQLITE_API int sqlite3_key_v2(
5387 sqlite3 *db, /* Database to be rekeyed */
5388 const char *zDbName, /* Name of the database */
5389 const void *pKey, int nKey /* The key */
5390);
5391
5392/*
5393** Change the key on an open database. If the current database is not
5394** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
5395** database is decrypted.
5396**
5397** The code to implement this API is not available in the public release
5398** of SQLite.
5399*/
5400SQLITE_API int sqlite3_rekey(
5401 sqlite3 *db, /* Database to be rekeyed */
5402 const void *pKey, int nKey /* The new key */
5403);
5404SQLITE_API int sqlite3_rekey_v2(
5405 sqlite3 *db, /* Database to be rekeyed */
5406 const char *zDbName, /* Name of the database */
5407 const void *pKey, int nKey /* The new key */
5408);
5409
5410/*
5411** Specify the activation key for a SEE database. Unless
5412** activated, none of the SEE routines will work.
5413*/
5414SQLITE_API void sqlite3_activate_see(
5415 const char *zPassPhrase /* Activation phrase */
5416);
5417#endif
5418
5419#ifdef SQLITE_ENABLE_CEROD
5420/*
5421** Specify the activation key for a CEROD database. Unless
5422** activated, none of the CEROD routines will work.
5423*/
5424SQLITE_API void sqlite3_activate_cerod(
5425 const char *zPassPhrase /* Activation phrase */
5426);
5427#endif
5428
5429/*
5430** CAPI3REF: Suspend Execution For A Short Time
5431**
5432** The sqlite3_sleep() function causes the current thread to suspend execution
5433** for at least a number of milliseconds specified in its parameter.
5434**
5435** If the operating system does not support sleep requests with
5436** millisecond time resolution, then the time will be rounded up to
5437** the nearest second. The number of milliseconds of sleep actually
5438** requested from the operating system is returned.
5439**
5440** ^SQLite implements this interface by calling the xSleep()
5441** method of the default [sqlite3_vfs] object. If the xSleep() method
5442** of the default VFS is not implemented correctly, or not implemented at
5443** all, then the behavior of sqlite3_sleep() may deviate from the description
5444** in the previous paragraphs.
5445*/
5446SQLITE_API int sqlite3_sleep(int);
5447
5448/*
5449** CAPI3REF: Name Of The Folder Holding Temporary Files
5450**
5451** ^(If this global variable is made to point to a string which is
5452** the name of a folder (a.k.a. directory), then all temporary files
5453** created by SQLite when using a built-in [sqlite3_vfs | VFS]
5454** will be placed in that directory.)^ ^If this variable
5455** is a NULL pointer, then SQLite performs a search for an appropriate
5456** temporary file directory.
5457**
5458** Applications are strongly discouraged from using this global variable.
5459** It is required to set a temporary folder on Windows Runtime (WinRT).
5460** But for all other platforms, it is highly recommended that applications
5461** neither read nor write this variable. This global variable is a relic
5462** that exists for backwards compatibility of legacy applications and should
5463** be avoided in new projects.
5464**
5465** It is not safe to read or modify this variable in more than one
5466** thread at a time. It is not safe to read or modify this variable
5467** if a [database connection] is being used at the same time in a separate
5468** thread.
5469** It is intended that this variable be set once
5470** as part of process initialization and before any SQLite interface
5471** routines have been called and that this variable remain unchanged
5472** thereafter.
5473**
5474** ^The [temp_store_directory pragma] may modify this variable and cause
5475** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
5476** the [temp_store_directory pragma] always assumes that any string
5477** that this variable points to is held in memory obtained from
5478** [sqlite3_malloc] and the pragma may attempt to free that memory
5479** using [sqlite3_free].
5480** Hence, if this variable is modified directly, either it should be
5481** made NULL or made to point to memory obtained from [sqlite3_malloc]
5482** or else the use of the [temp_store_directory pragma] should be avoided.
5483** Except when requested by the [temp_store_directory pragma], SQLite
5484** does not free the memory that sqlite3_temp_directory points to. If
5485** the application wants that memory to be freed, it must do
5486** so itself, taking care to only do so after all [database connection]
5487** objects have been destroyed.
5488**
5489** <b>Note to Windows Runtime users:</b> The temporary directory must be set
5490** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
5491** features that require the use of temporary files may fail. Here is an
5492** example of how to do this using C++ with the Windows Runtime:
5493**
5494** <blockquote><pre>
5495** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
5496** &nbsp; TemporaryFolder->Path->Data();
5497** char zPathBuf&#91;MAX_PATH + 1&#93;;
5498** memset(zPathBuf, 0, sizeof(zPathBuf));
5499** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
5500** &nbsp; NULL, NULL);
5501** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
5502** </pre></blockquote>
5503*/
5504SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
5505
5506/*
5507** CAPI3REF: Name Of The Folder Holding Database Files
5508**
5509** ^(If this global variable is made to point to a string which is
5510** the name of a folder (a.k.a. directory), then all database files
5511** specified with a relative pathname and created or accessed by
5512** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
5513** to be relative to that directory.)^ ^If this variable is a NULL
5514** pointer, then SQLite assumes that all database files specified
5515** with a relative pathname are relative to the current directory
5516** for the process. Only the windows VFS makes use of this global
5517** variable; it is ignored by the unix VFS.
5518**
5519** Changing the value of this variable while a database connection is
5520** open can result in a corrupt database.
5521**
5522** It is not safe to read or modify this variable in more than one
5523** thread at a time. It is not safe to read or modify this variable
5524** if a [database connection] is being used at the same time in a separate
5525** thread.
5526** It is intended that this variable be set once
5527** as part of process initialization and before any SQLite interface
5528** routines have been called and that this variable remain unchanged
5529** thereafter.
5530**
5531** ^The [data_store_directory pragma] may modify this variable and cause
5532** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
5533** the [data_store_directory pragma] always assumes that any string
5534** that this variable points to is held in memory obtained from
5535** [sqlite3_malloc] and the pragma may attempt to free that memory
5536** using [sqlite3_free].
5537** Hence, if this variable is modified directly, either it should be
5538** made NULL or made to point to memory obtained from [sqlite3_malloc]
5539** or else the use of the [data_store_directory pragma] should be avoided.
5540*/
5541SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
5542
5543/*
5544** CAPI3REF: Test For Auto-Commit Mode
5545** KEYWORDS: {autocommit mode}
5546** METHOD: sqlite3
5547**
5548** ^The sqlite3_get_autocommit() interface returns non-zero or
5549** zero if the given database connection is or is not in autocommit mode,
5550** respectively. ^Autocommit mode is on by default.
5551** ^Autocommit mode is disabled by a [BEGIN] statement.
5552** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
5553**
5554** If certain kinds of errors occur on a statement within a multi-statement
5555** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
5556** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
5557** transaction might be rolled back automatically. The only way to
5558** find out whether SQLite automatically rolled back the transaction after
5559** an error is to use this function.
5560**
5561** If another thread changes the autocommit status of the database
5562** connection while this routine is running, then the return value
5563** is undefined.
5564*/
5565SQLITE_API int sqlite3_get_autocommit(sqlite3*);
5566
5567/*
5568** CAPI3REF: Find The Database Handle Of A Prepared Statement
5569** METHOD: sqlite3_stmt
5570**
5571** ^The sqlite3_db_handle interface returns the [database connection] handle
5572** to which a [prepared statement] belongs. ^The [database connection]
5573** returned by sqlite3_db_handle is the same [database connection]
5574** that was the first argument
5575** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
5576** create the statement in the first place.
5577*/
5578SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
5579
5580/*
5581** CAPI3REF: Return The Filename For A Database Connection
5582** METHOD: sqlite3
5583**
5584** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
5585** associated with database N of connection D. ^The main database file
5586** has the name "main". If there is no attached database N on the database
5587** connection D, or if database N is a temporary or in-memory database, then
5588** a NULL pointer is returned.
5589**
5590** ^The filename returned by this function is the output of the
5591** xFullPathname method of the [VFS]. ^In other words, the filename
5592** will be an absolute pathname, even if the filename used
5593** to open the database originally was a URI or relative pathname.
5594*/
5595SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
5596
5597/*
5598** CAPI3REF: Determine if a database is read-only
5599** METHOD: sqlite3
5600**
5601** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
5602** of connection D is read-only, 0 if it is read/write, or -1 if N is not
5603** the name of a database on connection D.
5604*/
5605SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
5606
5607/*
5608** CAPI3REF: Find the next prepared statement
5609** METHOD: sqlite3
5610**
5611** ^This interface returns a pointer to the next [prepared statement] after
5612** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
5613** then this interface returns a pointer to the first prepared statement
5614** associated with the database connection pDb. ^If no prepared statement
5615** satisfies the conditions of this routine, it returns NULL.
5616**
5617** The [database connection] pointer D in a call to
5618** [sqlite3_next_stmt(D,S)] must refer to an open database
5619** connection and in particular must not be a NULL pointer.
5620*/
5621SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
5622
5623/*
5624** CAPI3REF: Commit And Rollback Notification Callbacks
5625** METHOD: sqlite3
5626**
5627** ^The sqlite3_commit_hook() interface registers a callback
5628** function to be invoked whenever a transaction is [COMMIT | committed].
5629** ^Any callback set by a previous call to sqlite3_commit_hook()
5630** for the same database connection is overridden.
5631** ^The sqlite3_rollback_hook() interface registers a callback
5632** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
5633** ^Any callback set by a previous call to sqlite3_rollback_hook()
5634** for the same database connection is overridden.
5635** ^The pArg argument is passed through to the callback.
5636** ^If the callback on a commit hook function returns non-zero,
5637** then the commit is converted into a rollback.
5638**
5639** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
5640** return the P argument from the previous call of the same function
5641** on the same [database connection] D, or NULL for
5642** the first call for each function on D.
5643**
5644** The commit and rollback hook callbacks are not reentrant.
5645** The callback implementation must not do anything that will modify
5646** the database connection that invoked the callback. Any actions
5647** to modify the database connection must be deferred until after the
5648** completion of the [sqlite3_step()] call that triggered the commit
5649** or rollback hook in the first place.
5650** Note that running any other SQL statements, including SELECT statements,
5651** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
5652** the database connections for the meaning of "modify" in this paragraph.
5653**
5654** ^Registering a NULL function disables the callback.
5655**
5656** ^When the commit hook callback routine returns zero, the [COMMIT]
5657** operation is allowed to continue normally. ^If the commit hook
5658** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
5659** ^The rollback hook is invoked on a rollback that results from a commit
5660** hook returning non-zero, just as it would be with any other rollback.
5661**
5662** ^For the purposes of this API, a transaction is said to have been
5663** rolled back if an explicit "ROLLBACK" statement is executed, or
5664** an error or constraint causes an implicit rollback to occur.
5665** ^The rollback callback is not invoked if a transaction is
5666** automatically rolled back because the database connection is closed.
5667**
5668** See also the [sqlite3_update_hook()] interface.
5669*/
5670SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
5671SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
5672
5673/*
5674** CAPI3REF: Data Change Notification Callbacks
5675** METHOD: sqlite3
5676**
5677** ^The sqlite3_update_hook() interface registers a callback function
5678** with the [database connection] identified by the first argument
5679** to be invoked whenever a row is updated, inserted or deleted in
5680** a [rowid table].
5681** ^Any callback set by a previous call to this function
5682** for the same database connection is overridden.
5683**
5684** ^The second argument is a pointer to the function to invoke when a
5685** row is updated, inserted or deleted in a rowid table.
5686** ^The first argument to the callback is a copy of the third argument
5687** to sqlite3_update_hook().
5688** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
5689** or [SQLITE_UPDATE], depending on the operation that caused the callback
5690** to be invoked.
5691** ^The third and fourth arguments to the callback contain pointers to the
5692** database and table name containing the affected row.
5693** ^The final callback parameter is the [rowid] of the row.
5694** ^In the case of an update, this is the [rowid] after the update takes place.
5695**
5696** ^(The update hook is not invoked when internal system tables are
5697** modified (i.e. sqlite_master and sqlite_sequence).)^
5698** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
5699**
5700** ^In the current implementation, the update hook
5701** is not invoked when conflicting rows are deleted because of an
5702** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
5703** invoked when rows are deleted using the [truncate optimization].
5704** The exceptions defined in this paragraph might change in a future
5705** release of SQLite.
5706**
5707** The update hook implementation must not do anything that will modify
5708** the database connection that invoked the update hook. Any actions
5709** to modify the database connection must be deferred until after the
5710** completion of the [sqlite3_step()] call that triggered the update hook.
5711** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
5712** database connections for the meaning of "modify" in this paragraph.
5713**
5714** ^The sqlite3_update_hook(D,C,P) function
5715** returns the P argument from the previous call
5716** on the same [database connection] D, or NULL for
5717** the first call on D.
5718**
5719** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
5720** and [sqlite3_preupdate_hook()] interfaces.
5721*/
5722SQLITE_API void *sqlite3_update_hook(
5723 sqlite3*,
5724 void(*)(void *,int ,char const *,char const *,sqlite3_int64),
5725 void*
5726);
5727
5728/*
5729** CAPI3REF: Enable Or Disable Shared Pager Cache
5730**
5731** ^(This routine enables or disables the sharing of the database cache
5732** and schema data structures between [database connection | connections]
5733** to the same database. Sharing is enabled if the argument is true
5734** and disabled if the argument is false.)^
5735**
5736** ^Cache sharing is enabled and disabled for an entire process.
5737** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
5738** In prior versions of SQLite,
5739** sharing was enabled or disabled for each thread separately.
5740**
5741** ^(The cache sharing mode set by this interface effects all subsequent
5742** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
5743** Existing database connections continue use the sharing mode
5744** that was in effect at the time they were opened.)^
5745**
5746** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
5747** successfully. An [error code] is returned otherwise.)^
5748**
5749** ^Shared cache is disabled by default. But this might change in
5750** future releases of SQLite. Applications that care about shared
5751** cache setting should set it explicitly.
5752**
5753** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
5754** and will always return SQLITE_MISUSE. On those systems,
5755** shared cache mode should be enabled per-database connection via
5756** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
5757**
5758** This interface is threadsafe on processors where writing a
5759** 32-bit integer is atomic.
5760**
5761** See Also: [SQLite Shared-Cache Mode]
5762*/
5763SQLITE_API int sqlite3_enable_shared_cache(int);
5764
5765/*
5766** CAPI3REF: Attempt To Free Heap Memory
5767**
5768** ^The sqlite3_release_memory() interface attempts to free N bytes
5769** of heap memory by deallocating non-essential memory allocations
5770** held by the database library. Memory used to cache database
5771** pages to improve performance is an example of non-essential memory.
5772** ^sqlite3_release_memory() returns the number of bytes actually freed,
5773** which might be more or less than the amount requested.
5774** ^The sqlite3_release_memory() routine is a no-op returning zero
5775** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5776**
5777** See also: [sqlite3_db_release_memory()]
5778*/
5779SQLITE_API int sqlite3_release_memory(int);
5780
5781/*
5782** CAPI3REF: Free Memory Used By A Database Connection
5783** METHOD: sqlite3
5784**
5785** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
5786** memory as possible from database connection D. Unlike the
5787** [sqlite3_release_memory()] interface, this interface is in effect even
5788** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
5789** omitted.
5790**
5791** See also: [sqlite3_release_memory()]
5792*/
5793SQLITE_API int sqlite3_db_release_memory(sqlite3*);
5794
5795/*
5796** CAPI3REF: Impose A Limit On Heap Size
5797**
5798** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
5799** soft limit on the amount of heap memory that may be allocated by SQLite.
5800** ^SQLite strives to keep heap memory utilization below the soft heap
5801** limit by reducing the number of pages held in the page cache
5802** as heap memory usages approaches the limit.
5803** ^The soft heap limit is "soft" because even though SQLite strives to stay
5804** below the limit, it will exceed the limit rather than generate
5805** an [SQLITE_NOMEM] error. In other words, the soft heap limit
5806** is advisory only.
5807**
5808** ^The return value from sqlite3_soft_heap_limit64() is the size of
5809** the soft heap limit prior to the call, or negative in the case of an
5810** error. ^If the argument N is negative
5811** then no change is made to the soft heap limit. Hence, the current
5812** size of the soft heap limit can be determined by invoking
5813** sqlite3_soft_heap_limit64() with a negative argument.
5814**
5815** ^If the argument N is zero then the soft heap limit is disabled.
5816**
5817** ^(The soft heap limit is not enforced in the current implementation
5818** if one or more of following conditions are true:
5819**
5820** <ul>
5821** <li> The soft heap limit is set to zero.
5822** <li> Memory accounting is disabled using a combination of the
5823** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
5824** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
5825** <li> An alternative page cache implementation is specified using
5826** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
5827** <li> The page cache allocates from its own memory pool supplied
5828** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
5829** from the heap.
5830** </ul>)^
5831**
5832** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]),
5833** the soft heap limit is enforced
5834** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
5835** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
5836** the soft heap limit is enforced on every memory allocation. Without
5837** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
5838** when memory is allocated by the page cache. Testing suggests that because
5839** the page cache is the predominate memory user in SQLite, most
5840** applications will achieve adequate soft heap limit enforcement without
5841** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5842**
5843** The circumstances under which SQLite will enforce the soft heap limit may
5844** changes in future releases of SQLite.
5845*/
5846SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
5847
5848/*
5849** CAPI3REF: Deprecated Soft Heap Limit Interface
5850** DEPRECATED
5851**
5852** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
5853** interface. This routine is provided for historical compatibility
5854** only. All new applications should use the
5855** [sqlite3_soft_heap_limit64()] interface rather than this one.
5856*/
5857SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
5858
5859
5860/*
5861** CAPI3REF: Extract Metadata About A Column Of A Table
5862** METHOD: sqlite3
5863**
5864** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
5865** information about column C of table T in database D
5866** on [database connection] X.)^ ^The sqlite3_table_column_metadata()
5867** interface returns SQLITE_OK and fills in the non-NULL pointers in
5868** the final five arguments with appropriate values if the specified
5869** column exists. ^The sqlite3_table_column_metadata() interface returns
5870** SQLITE_ERROR and if the specified column does not exist.
5871** ^If the column-name parameter to sqlite3_table_column_metadata() is a
5872** NULL pointer, then this routine simply checks for the existence of the
5873** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
5874** does not. If the table name parameter T in a call to
5875** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
5876** undefined behavior.
5877**
5878** ^The column is identified by the second, third and fourth parameters to
5879** this function. ^(The second parameter is either the name of the database
5880** (i.e. "main", "temp", or an attached database) containing the specified
5881** table or NULL.)^ ^If it is NULL, then all attached databases are searched
5882** for the table using the same algorithm used by the database engine to
5883** resolve unqualified table references.
5884**
5885** ^The third and fourth parameters to this function are the table and column
5886** name of the desired column, respectively.
5887**
5888** ^Metadata is returned by writing to the memory locations passed as the 5th
5889** and subsequent parameters to this function. ^Any of these arguments may be
5890** NULL, in which case the corresponding element of metadata is omitted.
5891**
5892** ^(<blockquote>
5893** <table border="1">
5894** <tr><th> Parameter <th> Output<br>Type <th> Description
5895**
5896** <tr><td> 5th <td> const char* <td> Data type
5897** <tr><td> 6th <td> const char* <td> Name of default collation sequence
5898** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
5899** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
5900** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
5901** </table>
5902** </blockquote>)^
5903**
5904** ^The memory pointed to by the character pointers returned for the
5905** declaration type and collation sequence is valid until the next
5906** call to any SQLite API function.
5907**
5908** ^If the specified table is actually a view, an [error code] is returned.
5909**
5910** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
5911** is not a [WITHOUT ROWID] table and an
5912** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
5913** parameters are set for the explicitly declared column. ^(If there is no
5914** [INTEGER PRIMARY KEY] column, then the outputs
5915** for the [rowid] are set as follows:
5916**
5917** <pre>
5918** data type: "INTEGER"
5919** collation sequence: "BINARY"
5920** not null: 0
5921** primary key: 1
5922** auto increment: 0
5923** </pre>)^
5924**
5925** ^This function causes all database schemas to be read from disk and
5926** parsed, if that has not already been done, and returns an error if
5927** any errors are encountered while loading the schema.
5928*/
5929SQLITE_API int sqlite3_table_column_metadata(
5930 sqlite3 *db, /* Connection handle */
5931 const char *zDbName, /* Database name or NULL */
5932 const char *zTableName, /* Table name */
5933 const char *zColumnName, /* Column name */
5934 char const **pzDataType, /* OUTPUT: Declared data type */
5935 char const **pzCollSeq, /* OUTPUT: Collation sequence name */
5936 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
5937 int *pPrimaryKey, /* OUTPUT: True if column part of PK */
5938 int *pAutoinc /* OUTPUT: True if column is auto-increment */
5939);
5940
5941/*
5942** CAPI3REF: Load An Extension
5943** METHOD: sqlite3
5944**
5945** ^This interface loads an SQLite extension library from the named file.
5946**
5947** ^The sqlite3_load_extension() interface attempts to load an
5948** [SQLite extension] library contained in the file zFile. If
5949** the file cannot be loaded directly, attempts are made to load
5950** with various operating-system specific extensions added.
5951** So for example, if "samplelib" cannot be loaded, then names like
5952** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
5953** be tried also.
5954**
5955** ^The entry point is zProc.
5956** ^(zProc may be 0, in which case SQLite will try to come up with an
5957** entry point name on its own. It first tries "sqlite3_extension_init".
5958** If that does not work, it constructs a name "sqlite3_X_init" where the
5959** X is consists of the lower-case equivalent of all ASCII alphabetic
5960** characters in the filename from the last "/" to the first following
5961** "." and omitting any initial "lib".)^
5962** ^The sqlite3_load_extension() interface returns
5963** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
5964** ^If an error occurs and pzErrMsg is not 0, then the
5965** [sqlite3_load_extension()] interface shall attempt to
5966** fill *pzErrMsg with error message text stored in memory
5967** obtained from [sqlite3_malloc()]. The calling function
5968** should free this memory by calling [sqlite3_free()].
5969**
5970** ^Extension loading must be enabled using
5971** [sqlite3_enable_load_extension()] or
5972** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
5973** prior to calling this API,
5974** otherwise an error will be returned.
5975**
5976** <b>Security warning:</b> It is recommended that the
5977** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
5978** interface. The use of the [sqlite3_enable_load_extension()] interface
5979** should be avoided. This will keep the SQL function [load_extension()]
5980** disabled and prevent SQL injections from giving attackers
5981** access to extension loading capabilities.
5982**
5983** See also the [load_extension() SQL function].
5984*/
5985SQLITE_API int sqlite3_load_extension(
5986 sqlite3 *db, /* Load the extension into this database connection */
5987 const char *zFile, /* Name of the shared library containing extension */
5988 const char *zProc, /* Entry point. Derived from zFile if 0 */
5989 char **pzErrMsg /* Put error message here if not 0 */
5990);
5991
5992/*
5993** CAPI3REF: Enable Or Disable Extension Loading
5994** METHOD: sqlite3
5995**
5996** ^So as not to open security holes in older applications that are
5997** unprepared to deal with [extension loading], and as a means of disabling
5998** [extension loading] while evaluating user-entered SQL, the following API
5999** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
6000**
6001** ^Extension loading is off by default.
6002** ^Call the sqlite3_enable_load_extension() routine with onoff==1
6003** to turn extension loading on and call it with onoff==0 to turn
6004** it back off again.
6005**
6006** ^This interface enables or disables both the C-API
6007** [sqlite3_load_extension()] and the SQL function [load_extension()].
6008** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
6009** to enable or disable only the C-API.)^
6010**
6011** <b>Security warning:</b> It is recommended that extension loading
6012** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
6013** rather than this interface, so the [load_extension()] SQL function
6014** remains disabled. This will prevent SQL injections from giving attackers
6015** access to extension loading capabilities.
6016*/
6017SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
6018
6019/*
6020** CAPI3REF: Automatically Load Statically Linked Extensions
6021**
6022** ^This interface causes the xEntryPoint() function to be invoked for
6023** each new [database connection] that is created. The idea here is that
6024** xEntryPoint() is the entry point for a statically linked [SQLite extension]
6025** that is to be automatically loaded into all new database connections.
6026**
6027** ^(Even though the function prototype shows that xEntryPoint() takes
6028** no arguments and returns void, SQLite invokes xEntryPoint() with three
6029** arguments and expects an integer result as if the signature of the
6030** entry point where as follows:
6031**
6032** <blockquote><pre>
6033** &nbsp; int xEntryPoint(
6034** &nbsp; sqlite3 *db,
6035** &nbsp; const char **pzErrMsg,
6036** &nbsp; const struct sqlite3_api_routines *pThunk
6037** &nbsp; );
6038** </pre></blockquote>)^
6039**
6040** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
6041** point to an appropriate error message (obtained from [sqlite3_mprintf()])
6042** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
6043** is NULL before calling the xEntryPoint(). ^SQLite will invoke
6044** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
6045** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
6046** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
6047**
6048** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
6049** on the list of automatic extensions is a harmless no-op. ^No entry point
6050** will be called more than once for each database connection that is opened.
6051**
6052** See also: [sqlite3_reset_auto_extension()]
6053** and [sqlite3_cancel_auto_extension()]
6054*/
6055SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
6056
6057/*
6058** CAPI3REF: Cancel Automatic Extension Loading
6059**
6060** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
6061** initialization routine X that was registered using a prior call to
6062** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)]
6063** routine returns 1 if initialization routine X was successfully
6064** unregistered and it returns 0 if X was not on the list of initialization
6065** routines.
6066*/
6067SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
6068
6069/*
6070** CAPI3REF: Reset Automatic Extension Loading
6071**
6072** ^This interface disables all automatic extensions previously
6073** registered using [sqlite3_auto_extension()].
6074*/
6075SQLITE_API void sqlite3_reset_auto_extension(void);
6076
6077/*
6078** The interface to the virtual-table mechanism is currently considered
6079** to be experimental. The interface might change in incompatible ways.
6080** If this is a problem for you, do not use the interface at this time.
6081**
6082** When the virtual-table mechanism stabilizes, we will declare the
6083** interface fixed, support it indefinitely, and remove this comment.
6084*/
6085
6086/*
6087** Structures used by the virtual table interface
6088*/
6089typedef struct sqlite3_vtab sqlite3_vtab;
6090typedef struct sqlite3_index_info sqlite3_index_info;
6091typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
6092typedef struct sqlite3_module sqlite3_module;
6093
6094/*
6095** CAPI3REF: Virtual Table Object
6096** KEYWORDS: sqlite3_module {virtual table module}
6097**
6098** This structure, sometimes called a "virtual table module",
6099** defines the implementation of a [virtual tables].
6100** This structure consists mostly of methods for the module.
6101**
6102** ^A virtual table module is created by filling in a persistent
6103** instance of this structure and passing a pointer to that instance
6104** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
6105** ^The registration remains valid until it is replaced by a different
6106** module or until the [database connection] closes. The content
6107** of this structure must not change while it is registered with
6108** any database connection.
6109*/
6110struct sqlite3_module {
6111 int iVersion;
6112 int (*xCreate)(sqlite3*, void *pAux,
6113 int argc, const char *const*argv,
6114 sqlite3_vtab **ppVTab, char**);
6115 int (*xConnect)(sqlite3*, void *pAux,
6116 int argc, const char *const*argv,
6117 sqlite3_vtab **ppVTab, char**);
6118 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
6119 int (*xDisconnect)(sqlite3_vtab *pVTab);
6120 int (*xDestroy)(sqlite3_vtab *pVTab);
6121 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
6122 int (*xClose)(sqlite3_vtab_cursor*);
6123 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
6124 int argc, sqlite3_value **argv);
6125 int (*xNext)(sqlite3_vtab_cursor*);
6126 int (*xEof)(sqlite3_vtab_cursor*);
6127 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
6128 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
6129 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
6130 int (*xBegin)(sqlite3_vtab *pVTab);
6131 int (*xSync)(sqlite3_vtab *pVTab);
6132 int (*xCommit)(sqlite3_vtab *pVTab);
6133 int (*xRollback)(sqlite3_vtab *pVTab);
6134 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
6135 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
6136 void **ppArg);
6137 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
6138 /* The methods above are in version 1 of the sqlite_module object. Those
6139 ** below are for version 2 and greater. */
6140 int (*xSavepoint)(sqlite3_vtab *pVTab, int);
6141 int (*xRelease)(sqlite3_vtab *pVTab, int);
6142 int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
6143};
6144
6145/*
6146** CAPI3REF: Virtual Table Indexing Information
6147** KEYWORDS: sqlite3_index_info
6148**
6149** The sqlite3_index_info structure and its substructures is used as part
6150** of the [virtual table] interface to
6151** pass information into and receive the reply from the [xBestIndex]
6152** method of a [virtual table module]. The fields under **Inputs** are the
6153** inputs to xBestIndex and are read-only. xBestIndex inserts its
6154** results into the **Outputs** fields.
6155**
6156** ^(The aConstraint[] array records WHERE clause constraints of the form:
6157**
6158** <blockquote>column OP expr</blockquote>
6159**
6160** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^ ^(The particular operator is
6161** stored in aConstraint[].op using one of the
6162** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
6163** ^(The index of the column is stored in
6164** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
6165** expr on the right-hand side can be evaluated (and thus the constraint
6166** is usable) and false if it cannot.)^
6167**
6168** ^The optimizer automatically inverts terms of the form "expr OP column"
6169** and makes other simplifications to the WHERE clause in an attempt to
6170** get as many WHERE clause terms into the form shown above as possible.
6171** ^The aConstraint[] array only reports WHERE clause terms that are
6172** relevant to the particular virtual table being queried.
6173**
6174** ^Information about the ORDER BY clause is stored in aOrderBy[].
6175** ^Each term of aOrderBy records a column of the ORDER BY clause.
6176**
6177** The colUsed field indicates which columns of the virtual table may be
6178** required by the current scan. Virtual table columns are numbered from
6179** zero in the order in which they appear within the CREATE TABLE statement
6180** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
6181** the corresponding bit is set within the colUsed mask if the column may be
6182** required by SQLite. If the table has at least 64 columns and any column
6183** to the right of the first 63 is required, then bit 63 of colUsed is also
6184** set. In other words, column iCol may be required if the expression
6185** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
6186** non-zero.
6187**
6188** The [xBestIndex] method must fill aConstraintUsage[] with information
6189** about what parameters to pass to xFilter. ^If argvIndex>0 then
6190** the right-hand side of the corresponding aConstraint[] is evaluated
6191** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
6192** is true, then the constraint is assumed to be fully handled by the
6193** virtual table and is not checked again by SQLite.)^
6194**
6195** ^The idxNum and idxPtr values are recorded and passed into the
6196** [xFilter] method.
6197** ^[sqlite3_free()] is used to free idxPtr if and only if
6198** needToFreeIdxPtr is true.
6199**
6200** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
6201** the correct order to satisfy the ORDER BY clause so that no separate
6202** sorting step is required.
6203**
6204** ^The estimatedCost value is an estimate of the cost of a particular
6205** strategy. A cost of N indicates that the cost of the strategy is similar
6206** to a linear scan of an SQLite table with N rows. A cost of log(N)
6207** indicates that the expense of the operation is similar to that of a
6208** binary search on a unique indexed field of an SQLite table with N rows.
6209**
6210** ^The estimatedRows value is an estimate of the number of rows that
6211** will be returned by the strategy.
6212**
6213** The xBestIndex method may optionally populate the idxFlags field with a
6214** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
6215** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
6216** assumes that the strategy may visit at most one row.
6217**
6218** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
6219** SQLite also assumes that if a call to the xUpdate() method is made as
6220** part of the same statement to delete or update a virtual table row and the
6221** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
6222** any database changes. In other words, if the xUpdate() returns
6223** SQLITE_CONSTRAINT, the database contents must be exactly as they were
6224** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
6225** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
6226** the xUpdate method are automatically rolled back by SQLite.
6227**
6228** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
6229** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
6230** If a virtual table extension is
6231** used with an SQLite version earlier than 3.8.2, the results of attempting
6232** to read or write the estimatedRows field are undefined (but are likely
6233** to included crashing the application). The estimatedRows field should
6234** therefore only be used if [sqlite3_libversion_number()] returns a
6235** value greater than or equal to 3008002. Similarly, the idxFlags field
6236** was added for [version 3.9.0] ([dateof:3.9.0]).
6237** It may therefore only be used if
6238** sqlite3_libversion_number() returns a value greater than or equal to
6239** 3009000.
6240*/
6241struct sqlite3_index_info {
6242 /* Inputs */
6243 int nConstraint; /* Number of entries in aConstraint */
6244 struct sqlite3_index_constraint {
6245 int iColumn; /* Column constrained. -1 for ROWID */
6246 unsigned char op; /* Constraint operator */
6247 unsigned char usable; /* True if this constraint is usable */
6248 int iTermOffset; /* Used internally - xBestIndex should ignore */
6249 } *aConstraint; /* Table of WHERE clause constraints */
6250 int nOrderBy; /* Number of terms in the ORDER BY clause */
6251 struct sqlite3_index_orderby {
6252 int iColumn; /* Column number */
6253 unsigned char desc; /* True for DESC. False for ASC. */
6254 } *aOrderBy; /* The ORDER BY clause */
6255 /* Outputs */
6256 struct sqlite3_index_constraint_usage {
6257 int argvIndex; /* if >0, constraint is part of argv to xFilter */
6258 unsigned char omit; /* Do not code a test for this constraint */
6259 } *aConstraintUsage;
6260 int idxNum; /* Number used to identify the index */
6261 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
6262 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
6263 int orderByConsumed; /* True if output is already ordered */
6264 double estimatedCost; /* Estimated cost of using this index */
6265 /* Fields below are only available in SQLite 3.8.2 and later */
6266 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */
6267 /* Fields below are only available in SQLite 3.9.0 and later */
6268 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */
6269 /* Fields below are only available in SQLite 3.10.0 and later */
6270 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */
6271};
6272
6273/*
6274** CAPI3REF: Virtual Table Scan Flags
6275*/
6276#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */
6277
6278/*
6279** CAPI3REF: Virtual Table Constraint Operator Codes
6280**
6281** These macros defined the allowed values for the
6282** [sqlite3_index_info].aConstraint[].op field. Each value represents
6283** an operator that is part of a constraint term in the wHERE clause of
6284** a query that uses a [virtual table].
6285*/
6286#define SQLITE_INDEX_CONSTRAINT_EQ 2
6287#define SQLITE_INDEX_CONSTRAINT_GT 4
6288#define SQLITE_INDEX_CONSTRAINT_LE 8
6289#define SQLITE_INDEX_CONSTRAINT_LT 16
6290#define SQLITE_INDEX_CONSTRAINT_GE 32
6291#define SQLITE_INDEX_CONSTRAINT_MATCH 64
6292#define SQLITE_INDEX_CONSTRAINT_LIKE 65
6293#define SQLITE_INDEX_CONSTRAINT_GLOB 66
6294#define SQLITE_INDEX_CONSTRAINT_REGEXP 67
6295#define SQLITE_INDEX_CONSTRAINT_NE 68
6296#define SQLITE_INDEX_CONSTRAINT_ISNOT 69
6297#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70
6298#define SQLITE_INDEX_CONSTRAINT_ISNULL 71
6299#define SQLITE_INDEX_CONSTRAINT_IS 72
6300
6301/*
6302** CAPI3REF: Register A Virtual Table Implementation
6303** METHOD: sqlite3
6304**
6305** ^These routines are used to register a new [virtual table module] name.
6306** ^Module names must be registered before
6307** creating a new [virtual table] using the module and before using a
6308** preexisting [virtual table] for the module.
6309**
6310** ^The module name is registered on the [database connection] specified
6311** by the first parameter. ^The name of the module is given by the
6312** second parameter. ^The third parameter is a pointer to
6313** the implementation of the [virtual table module]. ^The fourth
6314** parameter is an arbitrary client data pointer that is passed through
6315** into the [xCreate] and [xConnect] methods of the virtual table module
6316** when a new virtual table is be being created or reinitialized.
6317**
6318** ^The sqlite3_create_module_v2() interface has a fifth parameter which
6319** is a pointer to a destructor for the pClientData. ^SQLite will
6320** invoke the destructor function (if it is not NULL) when SQLite
6321** no longer needs the pClientData pointer. ^The destructor will also
6322** be invoked if the call to sqlite3_create_module_v2() fails.
6323** ^The sqlite3_create_module()
6324** interface is equivalent to sqlite3_create_module_v2() with a NULL
6325** destructor.
6326*/
6327SQLITE_API int sqlite3_create_module(
6328 sqlite3 *db, /* SQLite connection to register module with */
6329 const char *zName, /* Name of the module */
6330 const sqlite3_module *p, /* Methods for the module */
6331 void *pClientData /* Client data for xCreate/xConnect */
6332);
6333SQLITE_API int sqlite3_create_module_v2(
6334 sqlite3 *db, /* SQLite connection to register module with */
6335 const char *zName, /* Name of the module */
6336 const sqlite3_module *p, /* Methods for the module */
6337 void *pClientData, /* Client data for xCreate/xConnect */
6338 void(*xDestroy)(void*) /* Module destructor function */
6339);
6340
6341/*
6342** CAPI3REF: Virtual Table Instance Object
6343** KEYWORDS: sqlite3_vtab
6344**
6345** Every [virtual table module] implementation uses a subclass
6346** of this object to describe a particular instance
6347** of the [virtual table]. Each subclass will
6348** be tailored to the specific needs of the module implementation.
6349** The purpose of this superclass is to define certain fields that are
6350** common to all module implementations.
6351**
6352** ^Virtual tables methods can set an error message by assigning a
6353** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
6354** take care that any prior string is freed by a call to [sqlite3_free()]
6355** prior to assigning a new string to zErrMsg. ^After the error message
6356** is delivered up to the client application, the string will be automatically
6357** freed by sqlite3_free() and the zErrMsg field will be zeroed.
6358*/
6359struct sqlite3_vtab {
6360 const sqlite3_module *pModule; /* The module for this virtual table */
6361 int nRef; /* Number of open cursors */
6362 char *zErrMsg; /* Error message from sqlite3_mprintf() */
6363 /* Virtual table implementations will typically add additional fields */
6364};
6365
6366/*
6367** CAPI3REF: Virtual Table Cursor Object
6368** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
6369**
6370** Every [virtual table module] implementation uses a subclass of the
6371** following structure to describe cursors that point into the
6372** [virtual table] and are used
6373** to loop through the virtual table. Cursors are created using the
6374** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
6375** by the [sqlite3_module.xClose | xClose] method. Cursors are used
6376** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
6377** of the module. Each module implementation will define
6378** the content of a cursor structure to suit its own needs.
6379**
6380** This superclass exists in order to define fields of the cursor that
6381** are common to all implementations.
6382*/
6383struct sqlite3_vtab_cursor {
6384 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
6385 /* Virtual table implementations will typically add additional fields */
6386};
6387
6388/*
6389** CAPI3REF: Declare The Schema Of A Virtual Table
6390**
6391** ^The [xCreate] and [xConnect] methods of a
6392** [virtual table module] call this interface
6393** to declare the format (the names and datatypes of the columns) of
6394** the virtual tables they implement.
6395*/
6396SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
6397
6398/*
6399** CAPI3REF: Overload A Function For A Virtual Table
6400** METHOD: sqlite3
6401**
6402** ^(Virtual tables can provide alternative implementations of functions
6403** using the [xFindFunction] method of the [virtual table module].
6404** But global versions of those functions
6405** must exist in order to be overloaded.)^
6406**
6407** ^(This API makes sure a global version of a function with a particular
6408** name and number of parameters exists. If no such function exists
6409** before this API is called, a new function is created.)^ ^The implementation
6410** of the new function always causes an exception to be thrown. So
6411** the new function is not good for anything by itself. Its only
6412** purpose is to be a placeholder function that can be overloaded
6413** by a [virtual table].
6414*/
6415SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
6416
6417/*
6418** The interface to the virtual-table mechanism defined above (back up
6419** to a comment remarkably similar to this one) is currently considered
6420** to be experimental. The interface might change in incompatible ways.
6421** If this is a problem for you, do not use the interface at this time.
6422**
6423** When the virtual-table mechanism stabilizes, we will declare the
6424** interface fixed, support it indefinitely, and remove this comment.
6425*/
6426
6427/*
6428** CAPI3REF: A Handle To An Open BLOB
6429** KEYWORDS: {BLOB handle} {BLOB handles}
6430**
6431** An instance of this object represents an open BLOB on which
6432** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
6433** ^Objects of this type are created by [sqlite3_blob_open()]
6434** and destroyed by [sqlite3_blob_close()].
6435** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
6436** can be used to read or write small subsections of the BLOB.
6437** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
6438*/
6439typedef struct sqlite3_blob sqlite3_blob;
6440
6441/*
6442** CAPI3REF: Open A BLOB For Incremental I/O
6443** METHOD: sqlite3
6444** CONSTRUCTOR: sqlite3_blob
6445**
6446** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
6447** in row iRow, column zColumn, table zTable in database zDb;
6448** in other words, the same BLOB that would be selected by:
6449**
6450** <pre>
6451** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
6452** </pre>)^
6453**
6454** ^(Parameter zDb is not the filename that contains the database, but
6455** rather the symbolic name of the database. For attached databases, this is
6456** the name that appears after the AS keyword in the [ATTACH] statement.
6457** For the main database file, the database name is "main". For TEMP
6458** tables, the database name is "temp".)^
6459**
6460** ^If the flags parameter is non-zero, then the BLOB is opened for read
6461** and write access. ^If the flags parameter is zero, the BLOB is opened for
6462** read-only access.
6463**
6464** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
6465** in *ppBlob. Otherwise an [error code] is returned and, unless the error
6466** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
6467** the API is not misused, it is always safe to call [sqlite3_blob_close()]
6468** on *ppBlob after this function it returns.
6469**
6470** This function fails with SQLITE_ERROR if any of the following are true:
6471** <ul>
6472** <li> ^(Database zDb does not exist)^,
6473** <li> ^(Table zTable does not exist within database zDb)^,
6474** <li> ^(Table zTable is a WITHOUT ROWID table)^,
6475** <li> ^(Column zColumn does not exist)^,
6476** <li> ^(Row iRow is not present in the table)^,
6477** <li> ^(The specified column of row iRow contains a value that is not
6478** a TEXT or BLOB value)^,
6479** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
6480** constraint and the blob is being opened for read/write access)^,
6481** <li> ^([foreign key constraints | Foreign key constraints] are enabled,
6482** column zColumn is part of a [child key] definition and the blob is
6483** being opened for read/write access)^.
6484** </ul>
6485**
6486** ^Unless it returns SQLITE_MISUSE, this function sets the
6487** [database connection] error code and message accessible via
6488** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6489**
6490** A BLOB referenced by sqlite3_blob_open() may be read using the
6491** [sqlite3_blob_read()] interface and modified by using
6492** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a
6493** different row of the same table using the [sqlite3_blob_reopen()]
6494** interface. However, the column, table, or database of a [BLOB handle]
6495** cannot be changed after the [BLOB handle] is opened.
6496**
6497** ^(If the row that a BLOB handle points to is modified by an
6498** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
6499** then the BLOB handle is marked as "expired".
6500** This is true if any column of the row is changed, even a column
6501** other than the one the BLOB handle is open on.)^
6502** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
6503** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
6504** ^(Changes written into a BLOB prior to the BLOB expiring are not
6505** rolled back by the expiration of the BLOB. Such changes will eventually
6506** commit if the transaction continues to completion.)^
6507**
6508** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
6509** the opened blob. ^The size of a blob may not be changed by this
6510** interface. Use the [UPDATE] SQL command to change the size of a
6511** blob.
6512**
6513** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
6514** and the built-in [zeroblob] SQL function may be used to create a
6515** zero-filled blob to read or write using the incremental-blob interface.
6516**
6517** To avoid a resource leak, every open [BLOB handle] should eventually
6518** be released by a call to [sqlite3_blob_close()].
6519**
6520** See also: [sqlite3_blob_close()],
6521** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
6522** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
6523*/
6524SQLITE_API int sqlite3_blob_open(
6525 sqlite3*,
6526 const char *zDb,
6527 const char *zTable,
6528 const char *zColumn,
6529 sqlite3_int64 iRow,
6530 int flags,
6531 sqlite3_blob **ppBlob
6532);
6533
6534/*
6535** CAPI3REF: Move a BLOB Handle to a New Row
6536** METHOD: sqlite3_blob
6537**
6538** ^This function is used to move an existing [BLOB handle] so that it points
6539** to a different row of the same database table. ^The new row is identified
6540** by the rowid value passed as the second argument. Only the row can be
6541** changed. ^The database, table and column on which the blob handle is open
6542** remain the same. Moving an existing [BLOB handle] to a new row is
6543** faster than closing the existing handle and opening a new one.
6544**
6545** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
6546** it must exist and there must be either a blob or text value stored in
6547** the nominated column.)^ ^If the new row is not present in the table, or if
6548** it does not contain a blob or text value, or if another error occurs, an
6549** SQLite error code is returned and the blob handle is considered aborted.
6550** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
6551** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
6552** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
6553** always returns zero.
6554**
6555** ^This function sets the database handle error code and message.
6556*/
6557SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
6558
6559/*
6560** CAPI3REF: Close A BLOB Handle
6561** DESTRUCTOR: sqlite3_blob
6562**
6563** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
6564** unconditionally. Even if this routine returns an error code, the
6565** handle is still closed.)^
6566**
6567** ^If the blob handle being closed was opened for read-write access, and if
6568** the database is in auto-commit mode and there are no other open read-write
6569** blob handles or active write statements, the current transaction is
6570** committed. ^If an error occurs while committing the transaction, an error
6571** code is returned and the transaction rolled back.
6572**
6573** Calling this function with an argument that is not a NULL pointer or an
6574** open blob handle results in undefined behaviour. ^Calling this routine
6575** with a null pointer (such as would be returned by a failed call to
6576** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
6577** is passed a valid open blob handle, the values returned by the
6578** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
6579*/
6580SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
6581
6582/*
6583** CAPI3REF: Return The Size Of An Open BLOB
6584** METHOD: sqlite3_blob
6585**
6586** ^Returns the size in bytes of the BLOB accessible via the
6587** successfully opened [BLOB handle] in its only argument. ^The
6588** incremental blob I/O routines can only read or overwriting existing
6589** blob content; they cannot change the size of a blob.
6590**
6591** This routine only works on a [BLOB handle] which has been created
6592** by a prior successful call to [sqlite3_blob_open()] and which has not
6593** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6594** to this routine results in undefined and probably undesirable behavior.
6595*/
6596SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
6597
6598/*
6599** CAPI3REF: Read Data From A BLOB Incrementally
6600** METHOD: sqlite3_blob
6601**
6602** ^(This function is used to read data from an open [BLOB handle] into a
6603** caller-supplied buffer. N bytes of data are copied into buffer Z
6604** from the open BLOB, starting at offset iOffset.)^
6605**
6606** ^If offset iOffset is less than N bytes from the end of the BLOB,
6607** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
6608** less than zero, [SQLITE_ERROR] is returned and no data is read.
6609** ^The size of the blob (and hence the maximum value of N+iOffset)
6610** can be determined using the [sqlite3_blob_bytes()] interface.
6611**
6612** ^An attempt to read from an expired [BLOB handle] fails with an
6613** error code of [SQLITE_ABORT].
6614**
6615** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
6616** Otherwise, an [error code] or an [extended error code] is returned.)^
6617**
6618** This routine only works on a [BLOB handle] which has been created
6619** by a prior successful call to [sqlite3_blob_open()] and which has not
6620** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6621** to this routine results in undefined and probably undesirable behavior.
6622**
6623** See also: [sqlite3_blob_write()].
6624*/
6625SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
6626
6627/*
6628** CAPI3REF: Write Data Into A BLOB Incrementally
6629** METHOD: sqlite3_blob
6630**
6631** ^(This function is used to write data into an open [BLOB handle] from a
6632** caller-supplied buffer. N bytes of data are copied from the buffer Z
6633** into the open BLOB, starting at offset iOffset.)^
6634**
6635** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
6636** Otherwise, an [error code] or an [extended error code] is returned.)^
6637** ^Unless SQLITE_MISUSE is returned, this function sets the
6638** [database connection] error code and message accessible via
6639** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6640**
6641** ^If the [BLOB handle] passed as the first argument was not opened for
6642** writing (the flags parameter to [sqlite3_blob_open()] was zero),
6643** this function returns [SQLITE_READONLY].
6644**
6645** This function may only modify the contents of the BLOB; it is
6646** not possible to increase the size of a BLOB using this API.
6647** ^If offset iOffset is less than N bytes from the end of the BLOB,
6648** [SQLITE_ERROR] is returned and no data is written. The size of the
6649** BLOB (and hence the maximum value of N+iOffset) can be determined
6650** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
6651** than zero [SQLITE_ERROR] is returned and no data is written.
6652**
6653** ^An attempt to write to an expired [BLOB handle] fails with an
6654** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
6655** before the [BLOB handle] expired are not rolled back by the
6656** expiration of the handle, though of course those changes might
6657** have been overwritten by the statement that expired the BLOB handle
6658** or by other independent statements.
6659**
6660** This routine only works on a [BLOB handle] which has been created
6661** by a prior successful call to [sqlite3_blob_open()] and which has not
6662** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6663** to this routine results in undefined and probably undesirable behavior.
6664**
6665** See also: [sqlite3_blob_read()].
6666*/
6667SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
6668
6669/*
6670** CAPI3REF: Virtual File System Objects
6671**
6672** A virtual filesystem (VFS) is an [sqlite3_vfs] object
6673** that SQLite uses to interact
6674** with the underlying operating system. Most SQLite builds come with a
6675** single default VFS that is appropriate for the host computer.
6676** New VFSes can be registered and existing VFSes can be unregistered.
6677** The following interfaces are provided.
6678**
6679** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
6680** ^Names are case sensitive.
6681** ^Names are zero-terminated UTF-8 strings.
6682** ^If there is no match, a NULL pointer is returned.
6683** ^If zVfsName is NULL then the default VFS is returned.
6684**
6685** ^New VFSes are registered with sqlite3_vfs_register().
6686** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
6687** ^The same VFS can be registered multiple times without injury.
6688** ^To make an existing VFS into the default VFS, register it again
6689** with the makeDflt flag set. If two different VFSes with the
6690** same name are registered, the behavior is undefined. If a
6691** VFS is registered with a name that is NULL or an empty string,
6692** then the behavior is undefined.
6693**
6694** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
6695** ^(If the default VFS is unregistered, another VFS is chosen as
6696** the default. The choice for the new VFS is arbitrary.)^
6697*/
6698SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
6699SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
6700SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
6701
6702/*
6703** CAPI3REF: Mutexes
6704**
6705** The SQLite core uses these routines for thread
6706** synchronization. Though they are intended for internal
6707** use by SQLite, code that links against SQLite is
6708** permitted to use any of these routines.
6709**
6710** The SQLite source code contains multiple implementations
6711** of these mutex routines. An appropriate implementation
6712** is selected automatically at compile-time. The following
6713** implementations are available in the SQLite core:
6714**
6715** <ul>
6716** <li> SQLITE_MUTEX_PTHREADS
6717** <li> SQLITE_MUTEX_W32
6718** <li> SQLITE_MUTEX_NOOP
6719** </ul>
6720**
6721** The SQLITE_MUTEX_NOOP implementation is a set of routines
6722** that does no real locking and is appropriate for use in
6723** a single-threaded application. The SQLITE_MUTEX_PTHREADS and
6724** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
6725** and Windows.
6726**
6727** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
6728** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
6729** implementation is included with the library. In this case the
6730** application must supply a custom mutex implementation using the
6731** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
6732** before calling sqlite3_initialize() or any other public sqlite3_
6733** function that calls sqlite3_initialize().
6734**
6735** ^The sqlite3_mutex_alloc() routine allocates a new
6736** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
6737** routine returns NULL if it is unable to allocate the requested
6738** mutex. The argument to sqlite3_mutex_alloc() must one of these
6739** integer constants:
6740**
6741** <ul>
6742** <li> SQLITE_MUTEX_FAST
6743** <li> SQLITE_MUTEX_RECURSIVE
6744** <li> SQLITE_MUTEX_STATIC_MASTER
6745** <li> SQLITE_MUTEX_STATIC_MEM
6746** <li> SQLITE_MUTEX_STATIC_OPEN
6747** <li> SQLITE_MUTEX_STATIC_PRNG
6748** <li> SQLITE_MUTEX_STATIC_LRU
6749** <li> SQLITE_MUTEX_STATIC_PMEM
6750** <li> SQLITE_MUTEX_STATIC_APP1
6751** <li> SQLITE_MUTEX_STATIC_APP2
6752** <li> SQLITE_MUTEX_STATIC_APP3
6753** <li> SQLITE_MUTEX_STATIC_VFS1
6754** <li> SQLITE_MUTEX_STATIC_VFS2
6755** <li> SQLITE_MUTEX_STATIC_VFS3
6756** </ul>
6757**
6758** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
6759** cause sqlite3_mutex_alloc() to create
6760** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
6761** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
6762** The mutex implementation does not need to make a distinction
6763** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
6764** not want to. SQLite will only request a recursive mutex in
6765** cases where it really needs one. If a faster non-recursive mutex
6766** implementation is available on the host platform, the mutex subsystem
6767** might return such a mutex in response to SQLITE_MUTEX_FAST.
6768**
6769** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
6770** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
6771** a pointer to a static preexisting mutex. ^Nine static mutexes are
6772** used by the current version of SQLite. Future versions of SQLite
6773** may add additional static mutexes. Static mutexes are for internal
6774** use by SQLite only. Applications that use SQLite mutexes should
6775** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
6776** SQLITE_MUTEX_RECURSIVE.
6777**
6778** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
6779** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
6780** returns a different mutex on every call. ^For the static
6781** mutex types, the same mutex is returned on every call that has
6782** the same type number.
6783**
6784** ^The sqlite3_mutex_free() routine deallocates a previously
6785** allocated dynamic mutex. Attempting to deallocate a static
6786** mutex results in undefined behavior.
6787**
6788** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
6789** to enter a mutex. ^If another thread is already within the mutex,
6790** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
6791** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
6792** upon successful entry. ^(Mutexes created using
6793** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
6794** In such cases, the
6795** mutex must be exited an equal number of times before another thread
6796** can enter.)^ If the same thread tries to enter any mutex other
6797** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
6798**
6799** ^(Some systems (for example, Windows 95) do not support the operation
6800** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
6801** will always return SQLITE_BUSY. The SQLite core only ever uses
6802** sqlite3_mutex_try() as an optimization so this is acceptable
6803** behavior.)^
6804**
6805** ^The sqlite3_mutex_leave() routine exits a mutex that was
6806** previously entered by the same thread. The behavior
6807** is undefined if the mutex is not currently entered by the
6808** calling thread or is not currently allocated.
6809**
6810** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
6811** sqlite3_mutex_leave() is a NULL pointer, then all three routines
6812** behave as no-ops.
6813**
6814** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
6815*/
6816SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
6817SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
6818SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
6819SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
6820SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
6821
6822/*
6823** CAPI3REF: Mutex Methods Object
6824**
6825** An instance of this structure defines the low-level routines
6826** used to allocate and use mutexes.
6827**
6828** Usually, the default mutex implementations provided by SQLite are
6829** sufficient, however the application has the option of substituting a custom
6830** implementation for specialized deployments or systems for which SQLite
6831** does not provide a suitable implementation. In this case, the application
6832** creates and populates an instance of this structure to pass
6833** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
6834** Additionally, an instance of this structure can be used as an
6835** output variable when querying the system for the current mutex
6836** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
6837**
6838** ^The xMutexInit method defined by this structure is invoked as
6839** part of system initialization by the sqlite3_initialize() function.
6840** ^The xMutexInit routine is called by SQLite exactly once for each
6841** effective call to [sqlite3_initialize()].
6842**
6843** ^The xMutexEnd method defined by this structure is invoked as
6844** part of system shutdown by the sqlite3_shutdown() function. The
6845** implementation of this method is expected to release all outstanding
6846** resources obtained by the mutex methods implementation, especially
6847** those obtained by the xMutexInit method. ^The xMutexEnd()
6848** interface is invoked exactly once for each call to [sqlite3_shutdown()].
6849**
6850** ^(The remaining seven methods defined by this structure (xMutexAlloc,
6851** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
6852** xMutexNotheld) implement the following interfaces (respectively):
6853**
6854** <ul>
6855** <li> [sqlite3_mutex_alloc()] </li>
6856** <li> [sqlite3_mutex_free()] </li>
6857** <li> [sqlite3_mutex_enter()] </li>
6858** <li> [sqlite3_mutex_try()] </li>
6859** <li> [sqlite3_mutex_leave()] </li>
6860** <li> [sqlite3_mutex_held()] </li>
6861** <li> [sqlite3_mutex_notheld()] </li>
6862** </ul>)^
6863**
6864** The only difference is that the public sqlite3_XXX functions enumerated
6865** above silently ignore any invocations that pass a NULL pointer instead
6866** of a valid mutex handle. The implementations of the methods defined
6867** by this structure are not required to handle this case, the results
6868** of passing a NULL pointer instead of a valid mutex handle are undefined
6869** (i.e. it is acceptable to provide an implementation that segfaults if
6870** it is passed a NULL pointer).
6871**
6872** The xMutexInit() method must be threadsafe. It must be harmless to
6873** invoke xMutexInit() multiple times within the same process and without
6874** intervening calls to xMutexEnd(). Second and subsequent calls to
6875** xMutexInit() must be no-ops.
6876**
6877** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
6878** and its associates). Similarly, xMutexAlloc() must not use SQLite memory
6879** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
6880** memory allocation for a fast or recursive mutex.
6881**
6882** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
6883** called, but only if the prior call to xMutexInit returned SQLITE_OK.
6884** If xMutexInit fails in any way, it is expected to clean up after itself
6885** prior to returning.
6886*/
6887typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
6888struct sqlite3_mutex_methods {
6889 int (*xMutexInit)(void);
6890 int (*xMutexEnd)(void);
6891 sqlite3_mutex *(*xMutexAlloc)(int);
6892 void (*xMutexFree)(sqlite3_mutex *);
6893 void (*xMutexEnter)(sqlite3_mutex *);
6894 int (*xMutexTry)(sqlite3_mutex *);
6895 void (*xMutexLeave)(sqlite3_mutex *);
6896 int (*xMutexHeld)(sqlite3_mutex *);
6897 int (*xMutexNotheld)(sqlite3_mutex *);
6898};
6899
6900/*
6901** CAPI3REF: Mutex Verification Routines
6902**
6903** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
6904** are intended for use inside assert() statements. The SQLite core
6905** never uses these routines except inside an assert() and applications
6906** are advised to follow the lead of the core. The SQLite core only
6907** provides implementations for these routines when it is compiled
6908** with the SQLITE_DEBUG flag. External mutex implementations
6909** are only required to provide these routines if SQLITE_DEBUG is
6910** defined and if NDEBUG is not defined.
6911**
6912** These routines should return true if the mutex in their argument
6913** is held or not held, respectively, by the calling thread.
6914**
6915** The implementation is not required to provide versions of these
6916** routines that actually work. If the implementation does not provide working
6917** versions of these routines, it should at least provide stubs that always
6918** return true so that one does not get spurious assertion failures.
6919**
6920** If the argument to sqlite3_mutex_held() is a NULL pointer then
6921** the routine should return 1. This seems counter-intuitive since
6922** clearly the mutex cannot be held if it does not exist. But
6923** the reason the mutex does not exist is because the build is not
6924** using mutexes. And we do not want the assert() containing the
6925** call to sqlite3_mutex_held() to fail, so a non-zero return is
6926** the appropriate thing to do. The sqlite3_mutex_notheld()
6927** interface should also return 1 when given a NULL pointer.
6928*/
6929#ifndef NDEBUG
6930SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
6931SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
6932#endif
6933
6934/*
6935** CAPI3REF: Mutex Types
6936**
6937** The [sqlite3_mutex_alloc()] interface takes a single argument
6938** which is one of these integer constants.
6939**
6940** The set of static mutexes may change from one SQLite release to the
6941** next. Applications that override the built-in mutex logic must be
6942** prepared to accommodate additional static mutexes.
6943*/
6944#define SQLITE_MUTEX_FAST 0
6945#define SQLITE_MUTEX_RECURSIVE 1
6946#define SQLITE_MUTEX_STATIC_MASTER 2
6947#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
6948#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
6949#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
6950#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */
6951#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
6952#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
6953#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
6954#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */
6955#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */
6956#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */
6957#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */
6958#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */
6959#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */
6960
6961/*
6962** CAPI3REF: Retrieve the mutex for a database connection
6963** METHOD: sqlite3
6964**
6965** ^This interface returns a pointer the [sqlite3_mutex] object that
6966** serializes access to the [database connection] given in the argument
6967** when the [threading mode] is Serialized.
6968** ^If the [threading mode] is Single-thread or Multi-thread then this
6969** routine returns a NULL pointer.
6970*/
6971SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
6972
6973/*
6974** CAPI3REF: Low-Level Control Of Database Files
6975** METHOD: sqlite3
6976**
6977** ^The [sqlite3_file_control()] interface makes a direct call to the
6978** xFileControl method for the [sqlite3_io_methods] object associated
6979** with a particular database identified by the second argument. ^The
6980** name of the database is "main" for the main database or "temp" for the
6981** TEMP database, or the name that appears after the AS keyword for
6982** databases that are added using the [ATTACH] SQL command.
6983** ^A NULL pointer can be used in place of "main" to refer to the
6984** main database file.
6985** ^The third and fourth parameters to this routine
6986** are passed directly through to the second and third parameters of
6987** the xFileControl method. ^The return value of the xFileControl
6988** method becomes the return value of this routine.
6989**
6990** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
6991** a pointer to the underlying [sqlite3_file] object to be written into
6992** the space pointed to by the 4th parameter. ^The [SQLITE_FCNTL_FILE_POINTER]
6993** case is a short-circuit path which does not actually invoke the
6994** underlying sqlite3_io_methods.xFileControl method.
6995**
6996** ^If the second parameter (zDbName) does not match the name of any
6997** open database file, then SQLITE_ERROR is returned. ^This error
6998** code is not remembered and will not be recalled by [sqlite3_errcode()]
6999** or [sqlite3_errmsg()]. The underlying xFileControl method might
7000** also return SQLITE_ERROR. There is no way to distinguish between
7001** an incorrect zDbName and an SQLITE_ERROR return from the underlying
7002** xFileControl method.
7003**
7004** See also: [file control opcodes]
7005*/
7006SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
7007
7008/*
7009** CAPI3REF: Testing Interface
7010**
7011** ^The sqlite3_test_control() interface is used to read out internal
7012** state of SQLite and to inject faults into SQLite for testing
7013** purposes. ^The first parameter is an operation code that determines
7014** the number, meaning, and operation of all subsequent parameters.
7015**
7016** This interface is not for use by applications. It exists solely
7017** for verifying the correct operation of the SQLite library. Depending
7018** on how the SQLite library is compiled, this interface might not exist.
7019**
7020** The details of the operation codes, their meanings, the parameters
7021** they take, and what they do are all subject to change without notice.
7022** Unlike most of the SQLite API, this function is not guaranteed to
7023** operate consistently from one release to the next.
7024*/
7025SQLITE_API int sqlite3_test_control(int op, ...);
7026
7027/*
7028** CAPI3REF: Testing Interface Operation Codes
7029**
7030** These constants are the valid operation code parameters used
7031** as the first argument to [sqlite3_test_control()].
7032**
7033** These parameters and their meanings are subject to change
7034** without notice. These values are for testing purposes only.
7035** Applications should not use any of these parameters or the
7036** [sqlite3_test_control()] interface.
7037*/
7038#define SQLITE_TESTCTRL_FIRST 5
7039#define SQLITE_TESTCTRL_PRNG_SAVE 5
7040#define SQLITE_TESTCTRL_PRNG_RESTORE 6
7041#define SQLITE_TESTCTRL_PRNG_RESET 7
7042#define SQLITE_TESTCTRL_BITVEC_TEST 8
7043#define SQLITE_TESTCTRL_FAULT_INSTALL 9
7044#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
7045#define SQLITE_TESTCTRL_PENDING_BYTE 11
7046#define SQLITE_TESTCTRL_ASSERT 12
7047#define SQLITE_TESTCTRL_ALWAYS 13
7048#define SQLITE_TESTCTRL_RESERVE 14
7049#define SQLITE_TESTCTRL_OPTIMIZATIONS 15
7050#define SQLITE_TESTCTRL_ISKEYWORD 16
7051#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */
7052#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
7053#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */
7054#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19
7055#define SQLITE_TESTCTRL_NEVER_CORRUPT 20
7056#define SQLITE_TESTCTRL_VDBE_COVERAGE 21
7057#define SQLITE_TESTCTRL_BYTEORDER 22
7058#define SQLITE_TESTCTRL_ISINIT 23
7059#define SQLITE_TESTCTRL_SORTER_MMAP 24
7060#define SQLITE_TESTCTRL_IMPOSTER 25
7061#define SQLITE_TESTCTRL_PARSER_COVERAGE 26
7062#define SQLITE_TESTCTRL_LAST 26 /* Largest TESTCTRL */
7063
7064/*
7065** CAPI3REF: Dynamic String Object
7066** KEYWORDS: {dynamic string}
7067**
7068** An instance of the sqlite3_str object contains a dynamically-sized
7069** string under construction.
7070**
7071** The lifecycle of an sqlite3_str object is as follows:
7072** <ol>
7073** <li> The sqlite3_str object is created using [sqlite3_str_new()].
7074** <li> Text is appended to the sqlite3_str object using various
7075** methods, such as [sqlite3_str_appendf()].
7076** <li> The sqlite3_str object is destroyed and the string it created
7077** is returned using the [sqlite3_str_finish()] interface.
7078** </ol>
7079*/
7080typedef struct sqlite3_str sqlite3_str;
7081
7082/*
7083** CAPI3REF: Create A New Dynamic String Object
7084** CONSTRUCTOR: sqlite3_str
7085**
7086** The [sqlite3_str_new(D)] allocates and initializes a new [sqlite3_str]
7087** object. The [sqlite3_str_new(D)] interface returns NULL on an out-of-memory
7088** condition. To avoid memory leaks, the object returned by
7089** [sqlite3_str_new(D)] must be freed by a subsequent call to
7090** [sqlite3_str_finish(S)].
7091**
7092** If the D argument to [sqlite3_str_new(D)] is NULL then memory used to
7093** construct the string is always taken from the global memory pool used
7094** by [sqlite3_malloc64()]. If D is not NULL, then a private memory pool
7095** used by connection D might also be used. This private memory pool is
7096** faster, but is limited in space, and should only be used for transient
7097** allocations. The final string returned by [sqlite3_str_finish(X)] is
7098** always stored in space obtained from [sqlite3_malloc64()] regardless
7099** of whether or not the private per-connection memory pool is used during
7100** its construction.
7101*/
7102SQLITE_API sqlite3_str *sqlite3_str_new(sqlite3*);
7103
7104/*
7105** CAPI3REF: Finalize A Dynamic String
7106** DESTRUCTOR: sqlite3_str
7107**
7108** The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
7109** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
7110** that contains the constructed string. The calling application should
7111** pass the returned value to [sqlite3_free()] to avoid a memory leak.
7112** The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
7113** errors were encountered during construction of the string. The
7114** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the
7115** string in [sqlite3_str] object X is zero bytes long.
7116*/
7117SQLITE_API char *sqlite3_str_finish(sqlite3_str*);
7118
7119/*
7120** CAPI3REF: Add Content To A Dynamic String
7121** METHOD: sqlite3_str
7122**
7123** These interfaces add content to an sqlite3_str object previously obtained
7124** from [sqlite3_str_new()].
7125**
7126** The [sqlite3_str_appendf(X,F,...)] and
7127** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
7128** functionality of SQLite to append formatted text onto the end of
7129** [sqlite3_str] object X.
7130**
7131** The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
7132** onto the end of the [sqlite3_str] object X. N must be non-negative.
7133** S must contain at least N non-zero bytes of content. To append a
7134** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
7135** method instead.
7136**
7137** The [sqlite3_str_appendall(X,S)] method the complete content of
7138** zero-terminated string S onto the end of [sqlite3_str] object X.
7139**
7140** The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
7141** single-byte character C onto the end of [sqlite3_str] object X.
7142** This method can be used, for example, to add whitespace indentation.
7143**
7144** The [sqlite3_str_reset(X)] method resets the string under construction
7145** inside [sqlite3_str] object X back to zero bytes in length.
7146**
7147** These methods do not return a result code. If an error occurs, that fact
7148** is recorded in the [sqlite3_str] object and can be recovered by a
7149** subsequent call to [sqlite3_str_errcode(X)].
7150*/
7151SQLITE_API void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
7152SQLITE_API void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
7153SQLITE_API void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
7154SQLITE_API void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
7155SQLITE_API void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
7156SQLITE_API void sqlite3_str_reset(sqlite3_str*);
7157
7158/*
7159** CAPI3REF: Status Of A Dynamic String
7160** METHOD: sqlite3_str
7161**
7162** These interfaces return the current status of an [sqlite3_str] object.
7163**
7164** If any prior errors have occurred while constructing the dynamic string
7165** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
7166** an appropriate error code. The [sqlite3_str_errcode(X)] method returns
7167** [SQLITE_NOMEM] following any out-of-memory error, or
7168** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
7169** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
7170**
7171** The [sqlite3_str_length(X)] method returns the current length, in bytes,
7172** of the dynamic string under construction in [sqlite3_str] object X.
7173** The length returned by [sqlite3_str_length(X)] does not include the
7174** zero-termination byte.
7175**
7176** The [sqlite3_str_value(X)] method returns a pointer to the current
7177** content of the dynamic string under construction in X. The value
7178** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
7179** and might be freed or altered by any subsequent method on the same
7180** [sqlite3_str] object. Applications must not used the pointer returned
7181** [sqlite3_str_value(X)] after any subsequent method call on the same
7182** object. Applications may change the content of the string returned
7183** by [sqlite3_str_value(X)] as long as they do not write into any bytes
7184** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
7185** write any byte after any subsequent sqlite3_str method call.
7186*/
7187SQLITE_API int sqlite3_str_errcode(sqlite3_str*);
7188SQLITE_API int sqlite3_str_length(sqlite3_str*);
7189SQLITE_API char *sqlite3_str_value(sqlite3_str*);
7190
7191/*
7192** CAPI3REF: SQLite Runtime Status
7193**
7194** ^These interfaces are used to retrieve runtime status information
7195** about the performance of SQLite, and optionally to reset various
7196** highwater marks. ^The first argument is an integer code for
7197** the specific parameter to measure. ^(Recognized integer codes
7198** are of the form [status parameters | SQLITE_STATUS_...].)^
7199** ^The current value of the parameter is returned into *pCurrent.
7200** ^The highest recorded value is returned in *pHighwater. ^If the
7201** resetFlag is true, then the highest record value is reset after
7202** *pHighwater is written. ^(Some parameters do not record the highest
7203** value. For those parameters
7204** nothing is written into *pHighwater and the resetFlag is ignored.)^
7205** ^(Other parameters record only the highwater mark and not the current
7206** value. For these latter parameters nothing is written into *pCurrent.)^
7207**
7208** ^The sqlite3_status() and sqlite3_status64() routines return
7209** SQLITE_OK on success and a non-zero [error code] on failure.
7210**
7211** If either the current value or the highwater mark is too large to
7212** be represented by a 32-bit integer, then the values returned by
7213** sqlite3_status() are undefined.
7214**
7215** See also: [sqlite3_db_status()]
7216*/
7217SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
7218SQLITE_API int sqlite3_status64(
7219 int op,
7220 sqlite3_int64 *pCurrent,
7221 sqlite3_int64 *pHighwater,
7222 int resetFlag
7223);
7224
7225
7226/*
7227** CAPI3REF: Status Parameters
7228** KEYWORDS: {status parameters}
7229**
7230** These integer constants designate various run-time status parameters
7231** that can be returned by [sqlite3_status()].
7232**
7233** <dl>
7234** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
7235** <dd>This parameter is the current amount of memory checked out
7236** using [sqlite3_malloc()], either directly or indirectly. The
7237** figure includes calls made to [sqlite3_malloc()] by the application
7238** and internal memory usage by the SQLite library. Auxiliary page-cache
7239** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
7240** this parameter. The amount returned is the sum of the allocation
7241** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
7242**
7243** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
7244** <dd>This parameter records the largest memory allocation request
7245** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
7246** internal equivalents). Only the value returned in the
7247** *pHighwater parameter to [sqlite3_status()] is of interest.
7248** The value written into the *pCurrent parameter is undefined.</dd>)^
7249**
7250** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
7251** <dd>This parameter records the number of separate memory allocations
7252** currently checked out.</dd>)^
7253**
7254** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
7255** <dd>This parameter returns the number of pages used out of the
7256** [pagecache memory allocator] that was configured using
7257** [SQLITE_CONFIG_PAGECACHE]. The
7258** value returned is in pages, not in bytes.</dd>)^
7259**
7260** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
7261** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
7262** <dd>This parameter returns the number of bytes of page cache
7263** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
7264** buffer and where forced to overflow to [sqlite3_malloc()]. The
7265** returned value includes allocations that overflowed because they
7266** where too large (they were larger than the "sz" parameter to
7267** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
7268** no space was left in the page cache.</dd>)^
7269**
7270** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
7271** <dd>This parameter records the largest memory allocation request
7272** handed to [pagecache memory allocator]. Only the value returned in the
7273** *pHighwater parameter to [sqlite3_status()] is of interest.
7274** The value written into the *pCurrent parameter is undefined.</dd>)^
7275**
7276** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
7277** <dd>No longer used.</dd>
7278**
7279** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
7280** <dd>No longer used.</dd>
7281**
7282** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
7283** <dd>No longer used.</dd>
7284**
7285** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
7286** <dd>The *pHighwater parameter records the deepest parser stack.
7287** The *pCurrent value is undefined. The *pHighwater value is only
7288** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
7289** </dl>
7290**
7291** New status parameters may be added from time to time.
7292*/
7293#define SQLITE_STATUS_MEMORY_USED 0
7294#define SQLITE_STATUS_PAGECACHE_USED 1
7295#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
7296#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */
7297#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */
7298#define SQLITE_STATUS_MALLOC_SIZE 5
7299#define SQLITE_STATUS_PARSER_STACK 6
7300#define SQLITE_STATUS_PAGECACHE_SIZE 7
7301#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */
7302#define SQLITE_STATUS_MALLOC_COUNT 9
7303
7304/*
7305** CAPI3REF: Database Connection Status
7306** METHOD: sqlite3
7307**
7308** ^This interface is used to retrieve runtime status information
7309** about a single [database connection]. ^The first argument is the
7310** database connection object to be interrogated. ^The second argument
7311** is an integer constant, taken from the set of
7312** [SQLITE_DBSTATUS options], that
7313** determines the parameter to interrogate. The set of
7314** [SQLITE_DBSTATUS options] is likely
7315** to grow in future releases of SQLite.
7316**
7317** ^The current value of the requested parameter is written into *pCur
7318** and the highest instantaneous value is written into *pHiwtr. ^If
7319** the resetFlg is true, then the highest instantaneous value is
7320** reset back down to the current value.
7321**
7322** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
7323** non-zero [error code] on failure.
7324**
7325** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
7326*/
7327SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
7328
7329/*
7330** CAPI3REF: Status Parameters for database connections
7331** KEYWORDS: {SQLITE_DBSTATUS options}
7332**
7333** These constants are the available integer "verbs" that can be passed as
7334** the second argument to the [sqlite3_db_status()] interface.
7335**
7336** New verbs may be added in future releases of SQLite. Existing verbs
7337** might be discontinued. Applications should check the return code from
7338** [sqlite3_db_status()] to make sure that the call worked.
7339** The [sqlite3_db_status()] interface will return a non-zero error code
7340** if a discontinued or unsupported verb is invoked.
7341**
7342** <dl>
7343** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
7344** <dd>This parameter returns the number of lookaside memory slots currently
7345** checked out.</dd>)^
7346**
7347** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
7348** <dd>This parameter returns the number malloc attempts that were
7349** satisfied using lookaside memory. Only the high-water value is meaningful;
7350** the current value is always zero.)^
7351**
7352** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
7353** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
7354** <dd>This parameter returns the number malloc attempts that might have
7355** been satisfied using lookaside memory but failed due to the amount of
7356** memory requested being larger than the lookaside slot size.
7357** Only the high-water value is meaningful;
7358** the current value is always zero.)^
7359**
7360** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
7361** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
7362** <dd>This parameter returns the number malloc attempts that might have
7363** been satisfied using lookaside memory but failed due to all lookaside
7364** memory already being in use.
7365** Only the high-water value is meaningful;
7366** the current value is always zero.)^
7367**
7368** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
7369** <dd>This parameter returns the approximate number of bytes of heap
7370** memory used by all pager caches associated with the database connection.)^
7371** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
7372**
7373** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
7374** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
7375** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
7376** pager cache is shared between two or more connections the bytes of heap
7377** memory used by that pager cache is divided evenly between the attached
7378** connections.)^ In other words, if none of the pager caches associated
7379** with the database connection are shared, this request returns the same
7380** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
7381** shared, the value returned by this call will be smaller than that returned
7382** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
7383** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
7384**
7385** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
7386** <dd>This parameter returns the approximate number of bytes of heap
7387** memory used to store the schema for all databases associated
7388** with the connection - main, temp, and any [ATTACH]-ed databases.)^
7389** ^The full amount of memory used by the schemas is reported, even if the
7390** schema memory is shared with other database connections due to
7391** [shared cache mode] being enabled.
7392** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
7393**
7394** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
7395** <dd>This parameter returns the approximate number of bytes of heap
7396** and lookaside memory used by all prepared statements associated with
7397** the database connection.)^
7398** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
7399** </dd>
7400**
7401** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
7402** <dd>This parameter returns the number of pager cache hits that have
7403** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
7404** is always 0.
7405** </dd>
7406**
7407** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
7408** <dd>This parameter returns the number of pager cache misses that have
7409** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
7410** is always 0.
7411** </dd>
7412**
7413** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
7414** <dd>This parameter returns the number of dirty cache entries that have
7415** been written to disk. Specifically, the number of pages written to the
7416** wal file in wal mode databases, or the number of pages written to the
7417** database file in rollback mode databases. Any pages written as part of
7418** transaction rollback or database recovery operations are not included.
7419** If an IO or other error occurs while writing a page to disk, the effect
7420** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
7421** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
7422** </dd>
7423**
7424** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
7425** <dd>This parameter returns zero for the current value if and only if
7426** all foreign key constraints (deferred or immediate) have been
7427** resolved.)^ ^The highwater mark is always 0.
7428** </dd>
7429** </dl>
7430*/
7431#define SQLITE_DBSTATUS_LOOKASIDE_USED 0
7432#define SQLITE_DBSTATUS_CACHE_USED 1
7433#define SQLITE_DBSTATUS_SCHEMA_USED 2
7434#define SQLITE_DBSTATUS_STMT_USED 3
7435#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
7436#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
7437#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
7438#define SQLITE_DBSTATUS_CACHE_HIT 7
7439#define SQLITE_DBSTATUS_CACHE_MISS 8
7440#define SQLITE_DBSTATUS_CACHE_WRITE 9
7441#define SQLITE_DBSTATUS_DEFERRED_FKS 10
7442#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11
7443#define SQLITE_DBSTATUS_MAX 11 /* Largest defined DBSTATUS */
7444
7445
7446/*
7447** CAPI3REF: Prepared Statement Status
7448** METHOD: sqlite3_stmt
7449**
7450** ^(Each prepared statement maintains various
7451** [SQLITE_STMTSTATUS counters] that measure the number
7452** of times it has performed specific operations.)^ These counters can
7453** be used to monitor the performance characteristics of the prepared
7454** statements. For example, if the number of table steps greatly exceeds
7455** the number of table searches or result rows, that would tend to indicate
7456** that the prepared statement is using a full table scan rather than
7457** an index.
7458**
7459** ^(This interface is used to retrieve and reset counter values from
7460** a [prepared statement]. The first argument is the prepared statement
7461** object to be interrogated. The second argument
7462** is an integer code for a specific [SQLITE_STMTSTATUS counter]
7463** to be interrogated.)^
7464** ^The current value of the requested counter is returned.
7465** ^If the resetFlg is true, then the counter is reset to zero after this
7466** interface call returns.
7467**
7468** See also: [sqlite3_status()] and [sqlite3_db_status()].
7469*/
7470SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
7471
7472/*
7473** CAPI3REF: Status Parameters for prepared statements
7474** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
7475**
7476** These preprocessor macros define integer codes that name counter
7477** values associated with the [sqlite3_stmt_status()] interface.
7478** The meanings of the various counters are as follows:
7479**
7480** <dl>
7481** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
7482** <dd>^This is the number of times that SQLite has stepped forward in
7483** a table as part of a full table scan. Large numbers for this counter
7484** may indicate opportunities for performance improvement through
7485** careful use of indices.</dd>
7486**
7487** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
7488** <dd>^This is the number of sort operations that have occurred.
7489** A non-zero value in this counter may indicate an opportunity to
7490** improvement performance through careful use of indices.</dd>
7491**
7492** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
7493** <dd>^This is the number of rows inserted into transient indices that
7494** were created automatically in order to help joins run faster.
7495** A non-zero value in this counter may indicate an opportunity to
7496** improvement performance by adding permanent indices that do not
7497** need to be reinitialized each time the statement is run.</dd>
7498**
7499** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
7500** <dd>^This is the number of virtual machine operations executed
7501** by the prepared statement if that number is less than or equal
7502** to 2147483647. The number of virtual machine operations can be
7503** used as a proxy for the total work done by the prepared statement.
7504** If the number of virtual machine operations exceeds 2147483647
7505** then the value returned by this statement status code is undefined.
7506**
7507** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
7508** <dd>^This is the number of times that the prepare statement has been
7509** automatically regenerated due to schema changes or change to
7510** [bound parameters] that might affect the query plan.
7511**
7512** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
7513** <dd>^This is the number of times that the prepared statement has
7514** been run. A single "run" for the purposes of this counter is one
7515** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
7516** The counter is incremented on the first [sqlite3_step()] call of each
7517** cycle.
7518**
7519** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
7520** <dd>^This is the approximate number of bytes of heap memory
7521** used to store the prepared statement. ^This value is not actually
7522** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
7523** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
7524** </dd>
7525** </dl>
7526*/
7527#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
7528#define SQLITE_STMTSTATUS_SORT 2
7529#define SQLITE_STMTSTATUS_AUTOINDEX 3
7530#define SQLITE_STMTSTATUS_VM_STEP 4
7531#define SQLITE_STMTSTATUS_REPREPARE 5
7532#define SQLITE_STMTSTATUS_RUN 6
7533#define SQLITE_STMTSTATUS_MEMUSED 99
7534
7535/*
7536** CAPI3REF: Custom Page Cache Object
7537**
7538** The sqlite3_pcache type is opaque. It is implemented by
7539** the pluggable module. The SQLite core has no knowledge of
7540** its size or internal structure and never deals with the
7541** sqlite3_pcache object except by holding and passing pointers
7542** to the object.
7543**
7544** See [sqlite3_pcache_methods2] for additional information.
7545*/
7546typedef struct sqlite3_pcache sqlite3_pcache;
7547
7548/*
7549** CAPI3REF: Custom Page Cache Object
7550**
7551** The sqlite3_pcache_page object represents a single page in the
7552** page cache. The page cache will allocate instances of this
7553** object. Various methods of the page cache use pointers to instances
7554** of this object as parameters or as their return value.
7555**
7556** See [sqlite3_pcache_methods2] for additional information.
7557*/
7558typedef struct sqlite3_pcache_page sqlite3_pcache_page;
7559struct sqlite3_pcache_page {
7560 void *pBuf; /* The content of the page */
7561 void *pExtra; /* Extra information associated with the page */
7562};
7563
7564/*
7565** CAPI3REF: Application Defined Page Cache.
7566** KEYWORDS: {page cache}
7567**
7568** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
7569** register an alternative page cache implementation by passing in an
7570** instance of the sqlite3_pcache_methods2 structure.)^
7571** In many applications, most of the heap memory allocated by
7572** SQLite is used for the page cache.
7573** By implementing a
7574** custom page cache using this API, an application can better control
7575** the amount of memory consumed by SQLite, the way in which
7576** that memory is allocated and released, and the policies used to
7577** determine exactly which parts of a database file are cached and for
7578** how long.
7579**
7580** The alternative page cache mechanism is an
7581** extreme measure that is only needed by the most demanding applications.
7582** The built-in page cache is recommended for most uses.
7583**
7584** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
7585** internal buffer by SQLite within the call to [sqlite3_config]. Hence
7586** the application may discard the parameter after the call to
7587** [sqlite3_config()] returns.)^
7588**
7589** [[the xInit() page cache method]]
7590** ^(The xInit() method is called once for each effective
7591** call to [sqlite3_initialize()])^
7592** (usually only once during the lifetime of the process). ^(The xInit()
7593** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
7594** The intent of the xInit() method is to set up global data structures
7595** required by the custom page cache implementation.
7596** ^(If the xInit() method is NULL, then the
7597** built-in default page cache is used instead of the application defined
7598** page cache.)^
7599**
7600** [[the xShutdown() page cache method]]
7601** ^The xShutdown() method is called by [sqlite3_shutdown()].
7602** It can be used to clean up
7603** any outstanding resources before process shutdown, if required.
7604** ^The xShutdown() method may be NULL.
7605**
7606** ^SQLite automatically serializes calls to the xInit method,
7607** so the xInit method need not be threadsafe. ^The
7608** xShutdown method is only called from [sqlite3_shutdown()] so it does
7609** not need to be threadsafe either. All other methods must be threadsafe
7610** in multithreaded applications.
7611**
7612** ^SQLite will never invoke xInit() more than once without an intervening
7613** call to xShutdown().
7614**
7615** [[the xCreate() page cache methods]]
7616** ^SQLite invokes the xCreate() method to construct a new cache instance.
7617** SQLite will typically create one cache instance for each open database file,
7618** though this is not guaranteed. ^The
7619** first parameter, szPage, is the size in bytes of the pages that must
7620** be allocated by the cache. ^szPage will always a power of two. ^The
7621** second parameter szExtra is a number of bytes of extra storage
7622** associated with each page cache entry. ^The szExtra parameter will
7623** a number less than 250. SQLite will use the
7624** extra szExtra bytes on each page to store metadata about the underlying
7625** database page on disk. The value passed into szExtra depends
7626** on the SQLite version, the target platform, and how SQLite was compiled.
7627** ^The third argument to xCreate(), bPurgeable, is true if the cache being
7628** created will be used to cache database pages of a file stored on disk, or
7629** false if it is used for an in-memory database. The cache implementation
7630** does not have to do anything special based with the value of bPurgeable;
7631** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
7632** never invoke xUnpin() except to deliberately delete a page.
7633** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
7634** false will always have the "discard" flag set to true.
7635** ^Hence, a cache created with bPurgeable false will
7636** never contain any unpinned pages.
7637**
7638** [[the xCachesize() page cache method]]
7639** ^(The xCachesize() method may be called at any time by SQLite to set the
7640** suggested maximum cache-size (number of pages stored by) the cache
7641** instance passed as the first argument. This is the value configured using
7642** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
7643** parameter, the implementation is not required to do anything with this
7644** value; it is advisory only.
7645**
7646** [[the xPagecount() page cache methods]]
7647** The xPagecount() method must return the number of pages currently
7648** stored in the cache, both pinned and unpinned.
7649**
7650** [[the xFetch() page cache methods]]
7651** The xFetch() method locates a page in the cache and returns a pointer to
7652** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
7653** The pBuf element of the returned sqlite3_pcache_page object will be a
7654** pointer to a buffer of szPage bytes used to store the content of a
7655** single database page. The pExtra element of sqlite3_pcache_page will be
7656** a pointer to the szExtra bytes of extra storage that SQLite has requested
7657** for each entry in the page cache.
7658**
7659** The page to be fetched is determined by the key. ^The minimum key value
7660** is 1. After it has been retrieved using xFetch, the page is considered
7661** to be "pinned".
7662**
7663** If the requested page is already in the page cache, then the page cache
7664** implementation must return a pointer to the page buffer with its content
7665** intact. If the requested page is not already in the cache, then the
7666** cache implementation should use the value of the createFlag
7667** parameter to help it determined what action to take:
7668**
7669** <table border=1 width=85% align=center>
7670** <tr><th> createFlag <th> Behavior when page is not already in cache
7671** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
7672** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
7673** Otherwise return NULL.
7674** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
7675** NULL if allocating a new page is effectively impossible.
7676** </table>
7677**
7678** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
7679** will only use a createFlag of 2 after a prior call with a createFlag of 1
7680** failed.)^ In between the to xFetch() calls, SQLite may
7681** attempt to unpin one or more cache pages by spilling the content of
7682** pinned pages to disk and synching the operating system disk cache.
7683**
7684** [[the xUnpin() page cache method]]
7685** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
7686** as its second argument. If the third parameter, discard, is non-zero,
7687** then the page must be evicted from the cache.
7688** ^If the discard parameter is
7689** zero, then the page may be discarded or retained at the discretion of
7690** page cache implementation. ^The page cache implementation
7691** may choose to evict unpinned pages at any time.
7692**
7693** The cache must not perform any reference counting. A single
7694** call to xUnpin() unpins the page regardless of the number of prior calls
7695** to xFetch().
7696**
7697** [[the xRekey() page cache methods]]
7698** The xRekey() method is used to change the key value associated with the
7699** page passed as the second argument. If the cache
7700** previously contains an entry associated with newKey, it must be
7701** discarded. ^Any prior cache entry associated with newKey is guaranteed not
7702** to be pinned.
7703**
7704** When SQLite calls the xTruncate() method, the cache must discard all
7705** existing cache entries with page numbers (keys) greater than or equal
7706** to the value of the iLimit parameter passed to xTruncate(). If any
7707** of these pages are pinned, they are implicitly unpinned, meaning that
7708** they can be safely discarded.
7709**
7710** [[the xDestroy() page cache method]]
7711** ^The xDestroy() method is used to delete a cache allocated by xCreate().
7712** All resources associated with the specified cache should be freed. ^After
7713** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
7714** handle invalid, and will not use it with any other sqlite3_pcache_methods2
7715** functions.
7716**
7717** [[the xShrink() page cache method]]
7718** ^SQLite invokes the xShrink() method when it wants the page cache to
7719** free up as much of heap memory as possible. The page cache implementation
7720** is not obligated to free any memory, but well-behaved implementations should
7721** do their best.
7722*/
7723typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
7724struct sqlite3_pcache_methods2 {
7725 int iVersion;
7726 void *pArg;
7727 int (*xInit)(void*);
7728 void (*xShutdown)(void*);
7729 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
7730 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
7731 int (*xPagecount)(sqlite3_pcache*);
7732 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
7733 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
7734 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
7735 unsigned oldKey, unsigned newKey);
7736 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
7737 void (*xDestroy)(sqlite3_pcache*);
7738 void (*xShrink)(sqlite3_pcache*);
7739};
7740
7741/*
7742** This is the obsolete pcache_methods object that has now been replaced
7743** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
7744** retained in the header file for backwards compatibility only.
7745*/
7746typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
7747struct sqlite3_pcache_methods {
7748 void *pArg;
7749 int (*xInit)(void*);
7750 void (*xShutdown)(void*);
7751 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
7752 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
7753 int (*xPagecount)(sqlite3_pcache*);
7754 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
7755 void (*xUnpin)(sqlite3_pcache*, void*, int discard);
7756 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
7757 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
7758 void (*xDestroy)(sqlite3_pcache*);
7759};
7760
7761
7762/*
7763** CAPI3REF: Online Backup Object
7764**
7765** The sqlite3_backup object records state information about an ongoing
7766** online backup operation. ^The sqlite3_backup object is created by
7767** a call to [sqlite3_backup_init()] and is destroyed by a call to
7768** [sqlite3_backup_finish()].
7769**
7770** See Also: [Using the SQLite Online Backup API]
7771*/
7772typedef struct sqlite3_backup sqlite3_backup;
7773
7774/*
7775** CAPI3REF: Online Backup API.
7776**
7777** The backup API copies the content of one database into another.
7778** It is useful either for creating backups of databases or
7779** for copying in-memory databases to or from persistent files.
7780**
7781** See Also: [Using the SQLite Online Backup API]
7782**
7783** ^SQLite holds a write transaction open on the destination database file
7784** for the duration of the backup operation.
7785** ^The source database is read-locked only while it is being read;
7786** it is not locked continuously for the entire backup operation.
7787** ^Thus, the backup may be performed on a live source database without
7788** preventing other database connections from
7789** reading or writing to the source database while the backup is underway.
7790**
7791** ^(To perform a backup operation:
7792** <ol>
7793** <li><b>sqlite3_backup_init()</b> is called once to initialize the
7794** backup,
7795** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
7796** the data between the two databases, and finally
7797** <li><b>sqlite3_backup_finish()</b> is called to release all resources
7798** associated with the backup operation.
7799** </ol>)^
7800** There should be exactly one call to sqlite3_backup_finish() for each
7801** successful call to sqlite3_backup_init().
7802**
7803** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
7804**
7805** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
7806** [database connection] associated with the destination database
7807** and the database name, respectively.
7808** ^The database name is "main" for the main database, "temp" for the
7809** temporary database, or the name specified after the AS keyword in
7810** an [ATTACH] statement for an attached database.
7811** ^The S and M arguments passed to
7812** sqlite3_backup_init(D,N,S,M) identify the [database connection]
7813** and database name of the source database, respectively.
7814** ^The source and destination [database connections] (parameters S and D)
7815** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
7816** an error.
7817**
7818** ^A call to sqlite3_backup_init() will fail, returning NULL, if
7819** there is already a read or read-write transaction open on the
7820** destination database.
7821**
7822** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
7823** returned and an error code and error message are stored in the
7824** destination [database connection] D.
7825** ^The error code and message for the failed call to sqlite3_backup_init()
7826** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
7827** [sqlite3_errmsg16()] functions.
7828** ^A successful call to sqlite3_backup_init() returns a pointer to an
7829** [sqlite3_backup] object.
7830** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
7831** sqlite3_backup_finish() functions to perform the specified backup
7832** operation.
7833**
7834** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
7835**
7836** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
7837** the source and destination databases specified by [sqlite3_backup] object B.
7838** ^If N is negative, all remaining source pages are copied.
7839** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
7840** are still more pages to be copied, then the function returns [SQLITE_OK].
7841** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
7842** from source to destination, then it returns [SQLITE_DONE].
7843** ^If an error occurs while running sqlite3_backup_step(B,N),
7844** then an [error code] is returned. ^As well as [SQLITE_OK] and
7845** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
7846** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
7847** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
7848**
7849** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
7850** <ol>
7851** <li> the destination database was opened read-only, or
7852** <li> the destination database is using write-ahead-log journaling
7853** and the destination and source page sizes differ, or
7854** <li> the destination database is an in-memory database and the
7855** destination and source page sizes differ.
7856** </ol>)^
7857**
7858** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
7859** the [sqlite3_busy_handler | busy-handler function]
7860** is invoked (if one is specified). ^If the
7861** busy-handler returns non-zero before the lock is available, then
7862** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
7863** sqlite3_backup_step() can be retried later. ^If the source
7864** [database connection]
7865** is being used to write to the source database when sqlite3_backup_step()
7866** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
7867** case the call to sqlite3_backup_step() can be retried later on. ^(If
7868** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
7869** [SQLITE_READONLY] is returned, then
7870** there is no point in retrying the call to sqlite3_backup_step(). These
7871** errors are considered fatal.)^ The application must accept
7872** that the backup operation has failed and pass the backup operation handle
7873** to the sqlite3_backup_finish() to release associated resources.
7874**
7875** ^The first call to sqlite3_backup_step() obtains an exclusive lock
7876** on the destination file. ^The exclusive lock is not released until either
7877** sqlite3_backup_finish() is called or the backup operation is complete
7878** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
7879** sqlite3_backup_step() obtains a [shared lock] on the source database that
7880** lasts for the duration of the sqlite3_backup_step() call.
7881** ^Because the source database is not locked between calls to
7882** sqlite3_backup_step(), the source database may be modified mid-way
7883** through the backup process. ^If the source database is modified by an
7884** external process or via a database connection other than the one being
7885** used by the backup operation, then the backup will be automatically
7886** restarted by the next call to sqlite3_backup_step(). ^If the source
7887** database is modified by the using the same database connection as is used
7888** by the backup operation, then the backup database is automatically
7889** updated at the same time.
7890**
7891** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
7892**
7893** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
7894** application wishes to abandon the backup operation, the application
7895** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
7896** ^The sqlite3_backup_finish() interfaces releases all
7897** resources associated with the [sqlite3_backup] object.
7898** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
7899** active write-transaction on the destination database is rolled back.
7900** The [sqlite3_backup] object is invalid
7901** and may not be used following a call to sqlite3_backup_finish().
7902**
7903** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
7904** sqlite3_backup_step() errors occurred, regardless or whether or not
7905** sqlite3_backup_step() completed.
7906** ^If an out-of-memory condition or IO error occurred during any prior
7907** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
7908** sqlite3_backup_finish() returns the corresponding [error code].
7909**
7910** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
7911** is not a permanent error and does not affect the return value of
7912** sqlite3_backup_finish().
7913**
7914** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
7915** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
7916**
7917** ^The sqlite3_backup_remaining() routine returns the number of pages still
7918** to be backed up at the conclusion of the most recent sqlite3_backup_step().
7919** ^The sqlite3_backup_pagecount() routine returns the total number of pages
7920** in the source database at the conclusion of the most recent
7921** sqlite3_backup_step().
7922** ^(The values returned by these functions are only updated by
7923** sqlite3_backup_step(). If the source database is modified in a way that
7924** changes the size of the source database or the number of pages remaining,
7925** those changes are not reflected in the output of sqlite3_backup_pagecount()
7926** and sqlite3_backup_remaining() until after the next
7927** sqlite3_backup_step().)^
7928**
7929** <b>Concurrent Usage of Database Handles</b>
7930**
7931** ^The source [database connection] may be used by the application for other
7932** purposes while a backup operation is underway or being initialized.
7933** ^If SQLite is compiled and configured to support threadsafe database
7934** connections, then the source database connection may be used concurrently
7935** from within other threads.
7936**
7937** However, the application must guarantee that the destination
7938** [database connection] is not passed to any other API (by any thread) after
7939** sqlite3_backup_init() is called and before the corresponding call to
7940** sqlite3_backup_finish(). SQLite does not currently check to see
7941** if the application incorrectly accesses the destination [database connection]
7942** and so no error code is reported, but the operations may malfunction
7943** nevertheless. Use of the destination database connection while a
7944** backup is in progress might also also cause a mutex deadlock.
7945**
7946** If running in [shared cache mode], the application must
7947** guarantee that the shared cache used by the destination database
7948** is not accessed while the backup is running. In practice this means
7949** that the application must guarantee that the disk file being
7950** backed up to is not accessed by any connection within the process,
7951** not just the specific connection that was passed to sqlite3_backup_init().
7952**
7953** The [sqlite3_backup] object itself is partially threadsafe. Multiple
7954** threads may safely make multiple concurrent calls to sqlite3_backup_step().
7955** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
7956** APIs are not strictly speaking threadsafe. If they are invoked at the
7957** same time as another thread is invoking sqlite3_backup_step() it is
7958** possible that they return invalid values.
7959*/
7960SQLITE_API sqlite3_backup *sqlite3_backup_init(
7961 sqlite3 *pDest, /* Destination database handle */
7962 const char *zDestName, /* Destination database name */
7963 sqlite3 *pSource, /* Source database handle */
7964 const char *zSourceName /* Source database name */
7965);
7966SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
7967SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
7968SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
7969SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
7970
7971/*
7972** CAPI3REF: Unlock Notification
7973** METHOD: sqlite3
7974**
7975** ^When running in shared-cache mode, a database operation may fail with
7976** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
7977** individual tables within the shared-cache cannot be obtained. See
7978** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
7979** ^This API may be used to register a callback that SQLite will invoke
7980** when the connection currently holding the required lock relinquishes it.
7981** ^This API is only available if the library was compiled with the
7982** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
7983**
7984** See Also: [Using the SQLite Unlock Notification Feature].
7985**
7986** ^Shared-cache locks are released when a database connection concludes
7987** its current transaction, either by committing it or rolling it back.
7988**
7989** ^When a connection (known as the blocked connection) fails to obtain a
7990** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
7991** identity of the database connection (the blocking connection) that
7992** has locked the required resource is stored internally. ^After an
7993** application receives an SQLITE_LOCKED error, it may call the
7994** sqlite3_unlock_notify() method with the blocked connection handle as
7995** the first argument to register for a callback that will be invoked
7996** when the blocking connections current transaction is concluded. ^The
7997** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
7998** call that concludes the blocking connections transaction.
7999**
8000** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
8001** there is a chance that the blocking connection will have already
8002** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
8003** If this happens, then the specified callback is invoked immediately,
8004** from within the call to sqlite3_unlock_notify().)^
8005**
8006** ^If the blocked connection is attempting to obtain a write-lock on a
8007** shared-cache table, and more than one other connection currently holds
8008** a read-lock on the same table, then SQLite arbitrarily selects one of
8009** the other connections to use as the blocking connection.
8010**
8011** ^(There may be at most one unlock-notify callback registered by a
8012** blocked connection. If sqlite3_unlock_notify() is called when the
8013** blocked connection already has a registered unlock-notify callback,
8014** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
8015** called with a NULL pointer as its second argument, then any existing
8016** unlock-notify callback is canceled. ^The blocked connections
8017** unlock-notify callback may also be canceled by closing the blocked
8018** connection using [sqlite3_close()].
8019**
8020** The unlock-notify callback is not reentrant. If an application invokes
8021** any sqlite3_xxx API functions from within an unlock-notify callback, a
8022** crash or deadlock may be the result.
8023**
8024** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
8025** returns SQLITE_OK.
8026**
8027** <b>Callback Invocation Details</b>
8028**
8029** When an unlock-notify callback is registered, the application provides a
8030** single void* pointer that is passed to the callback when it is invoked.
8031** However, the signature of the callback function allows SQLite to pass
8032** it an array of void* context pointers. The first argument passed to
8033** an unlock-notify callback is a pointer to an array of void* pointers,
8034** and the second is the number of entries in the array.
8035**
8036** When a blocking connections transaction is concluded, there may be
8037** more than one blocked connection that has registered for an unlock-notify
8038** callback. ^If two or more such blocked connections have specified the
8039** same callback function, then instead of invoking the callback function
8040** multiple times, it is invoked once with the set of void* context pointers
8041** specified by the blocked connections bundled together into an array.
8042** This gives the application an opportunity to prioritize any actions
8043** related to the set of unblocked database connections.
8044**
8045** <b>Deadlock Detection</b>
8046**
8047** Assuming that after registering for an unlock-notify callback a
8048** database waits for the callback to be issued before taking any further
8049** action (a reasonable assumption), then using this API may cause the
8050** application to deadlock. For example, if connection X is waiting for
8051** connection Y's transaction to be concluded, and similarly connection
8052** Y is waiting on connection X's transaction, then neither connection
8053** will proceed and the system may remain deadlocked indefinitely.
8054**
8055** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
8056** detection. ^If a given call to sqlite3_unlock_notify() would put the
8057** system in a deadlocked state, then SQLITE_LOCKED is returned and no
8058** unlock-notify callback is registered. The system is said to be in
8059** a deadlocked state if connection A has registered for an unlock-notify
8060** callback on the conclusion of connection B's transaction, and connection
8061** B has itself registered for an unlock-notify callback when connection
8062** A's transaction is concluded. ^Indirect deadlock is also detected, so
8063** the system is also considered to be deadlocked if connection B has
8064** registered for an unlock-notify callback on the conclusion of connection
8065** C's transaction, where connection C is waiting on connection A. ^Any
8066** number of levels of indirection are allowed.
8067**
8068** <b>The "DROP TABLE" Exception</b>
8069**
8070** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
8071** always appropriate to call sqlite3_unlock_notify(). There is however,
8072** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
8073** SQLite checks if there are any currently executing SELECT statements
8074** that belong to the same connection. If there are, SQLITE_LOCKED is
8075** returned. In this case there is no "blocking connection", so invoking
8076** sqlite3_unlock_notify() results in the unlock-notify callback being
8077** invoked immediately. If the application then re-attempts the "DROP TABLE"
8078** or "DROP INDEX" query, an infinite loop might be the result.
8079**
8080** One way around this problem is to check the extended error code returned
8081** by an sqlite3_step() call. ^(If there is a blocking connection, then the
8082** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
8083** the special "DROP TABLE/INDEX" case, the extended error code is just
8084** SQLITE_LOCKED.)^
8085*/
8086SQLITE_API int sqlite3_unlock_notify(
8087 sqlite3 *pBlocked, /* Waiting connection */
8088 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
8089 void *pNotifyArg /* Argument to pass to xNotify */
8090);
8091
8092
8093/*
8094** CAPI3REF: String Comparison
8095**
8096** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
8097** and extensions to compare the contents of two buffers containing UTF-8
8098** strings in a case-independent fashion, using the same definition of "case
8099** independence" that SQLite uses internally when comparing identifiers.
8100*/
8101SQLITE_API int sqlite3_stricmp(const char *, const char *);
8102SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
8103
8104/*
8105** CAPI3REF: String Globbing
8106*
8107** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
8108** string X matches the [GLOB] pattern P.
8109** ^The definition of [GLOB] pattern matching used in
8110** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
8111** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function
8112** is case sensitive.
8113**
8114** Note that this routine returns zero on a match and non-zero if the strings
8115** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
8116**
8117** See also: [sqlite3_strlike()].
8118*/
8119SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
8120
8121/*
8122** CAPI3REF: String LIKE Matching
8123*
8124** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
8125** string X matches the [LIKE] pattern P with escape character E.
8126** ^The definition of [LIKE] pattern matching used in
8127** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
8128** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without
8129** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
8130** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
8131** insensitive - equivalent upper and lower case ASCII characters match
8132** one another.
8133**
8134** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
8135** only ASCII characters are case folded.
8136**
8137** Note that this routine returns zero on a match and non-zero if the strings
8138** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
8139**
8140** See also: [sqlite3_strglob()].
8141*/
8142SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
8143
8144/*
8145** CAPI3REF: Error Logging Interface
8146**
8147** ^The [sqlite3_log()] interface writes a message into the [error log]
8148** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
8149** ^If logging is enabled, the zFormat string and subsequent arguments are
8150** used with [sqlite3_snprintf()] to generate the final output string.
8151**
8152** The sqlite3_log() interface is intended for use by extensions such as
8153** virtual tables, collating functions, and SQL functions. While there is
8154** nothing to prevent an application from calling sqlite3_log(), doing so
8155** is considered bad form.
8156**
8157** The zFormat string must not be NULL.
8158**
8159** To avoid deadlocks and other threading problems, the sqlite3_log() routine
8160** will not use dynamically allocated memory. The log message is stored in
8161** a fixed-length buffer on the stack. If the log message is longer than
8162** a few hundred characters, it will be truncated to the length of the
8163** buffer.
8164*/
8165SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
8166
8167/*
8168** CAPI3REF: Write-Ahead Log Commit Hook
8169** METHOD: sqlite3
8170**
8171** ^The [sqlite3_wal_hook()] function is used to register a callback that
8172** is invoked each time data is committed to a database in wal mode.
8173**
8174** ^(The callback is invoked by SQLite after the commit has taken place and
8175** the associated write-lock on the database released)^, so the implementation
8176** may read, write or [checkpoint] the database as required.
8177**
8178** ^The first parameter passed to the callback function when it is invoked
8179** is a copy of the third parameter passed to sqlite3_wal_hook() when
8180** registering the callback. ^The second is a copy of the database handle.
8181** ^The third parameter is the name of the database that was written to -
8182** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
8183** is the number of pages currently in the write-ahead log file,
8184** including those that were just committed.
8185**
8186** The callback function should normally return [SQLITE_OK]. ^If an error
8187** code is returned, that error will propagate back up through the
8188** SQLite code base to cause the statement that provoked the callback
8189** to report an error, though the commit will have still occurred. If the
8190** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
8191** that does not correspond to any valid SQLite error code, the results
8192** are undefined.
8193**
8194** A single database handle may have at most a single write-ahead log callback
8195** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
8196** previously registered write-ahead log callback. ^Note that the
8197** [sqlite3_wal_autocheckpoint()] interface and the
8198** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
8199** overwrite any prior [sqlite3_wal_hook()] settings.
8200*/
8201SQLITE_API void *sqlite3_wal_hook(
8202 sqlite3*,
8203 int(*)(void *,sqlite3*,const char*,int),
8204 void*
8205);
8206
8207/*
8208** CAPI3REF: Configure an auto-checkpoint
8209** METHOD: sqlite3
8210**
8211** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
8212** [sqlite3_wal_hook()] that causes any database on [database connection] D
8213** to automatically [checkpoint]
8214** after committing a transaction if there are N or
8215** more frames in the [write-ahead log] file. ^Passing zero or
8216** a negative value as the nFrame parameter disables automatic
8217** checkpoints entirely.
8218**
8219** ^The callback registered by this function replaces any existing callback
8220** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
8221** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
8222** configured by this function.
8223**
8224** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
8225** from SQL.
8226**
8227** ^Checkpoints initiated by this mechanism are
8228** [sqlite3_wal_checkpoint_v2|PASSIVE].
8229**
8230** ^Every new [database connection] defaults to having the auto-checkpoint
8231** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
8232** pages. The use of this interface
8233** is only necessary if the default setting is found to be suboptimal
8234** for a particular application.
8235*/
8236SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
8237
8238/*
8239** CAPI3REF: Checkpoint a database
8240** METHOD: sqlite3
8241**
8242** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
8243** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
8244**
8245** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
8246** [write-ahead log] for database X on [database connection] D to be
8247** transferred into the database file and for the write-ahead log to
8248** be reset. See the [checkpointing] documentation for addition
8249** information.
8250**
8251** This interface used to be the only way to cause a checkpoint to
8252** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
8253** interface was added. This interface is retained for backwards
8254** compatibility and as a convenience for applications that need to manually
8255** start a callback but which do not need the full power (and corresponding
8256** complication) of [sqlite3_wal_checkpoint_v2()].
8257*/
8258SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
8259
8260/*
8261** CAPI3REF: Checkpoint a database
8262** METHOD: sqlite3
8263**
8264** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
8265** operation on database X of [database connection] D in mode M. Status
8266** information is written back into integers pointed to by L and C.)^
8267** ^(The M parameter must be a valid [checkpoint mode]:)^
8268**
8269** <dl>
8270** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
8271** ^Checkpoint as many frames as possible without waiting for any database
8272** readers or writers to finish, then sync the database file if all frames
8273** in the log were checkpointed. ^The [busy-handler callback]
8274** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
8275** ^On the other hand, passive mode might leave the checkpoint unfinished
8276** if there are concurrent readers or writers.
8277**
8278** <dt>SQLITE_CHECKPOINT_FULL<dd>
8279** ^This mode blocks (it invokes the
8280** [sqlite3_busy_handler|busy-handler callback]) until there is no
8281** database writer and all readers are reading from the most recent database
8282** snapshot. ^It then checkpoints all frames in the log file and syncs the
8283** database file. ^This mode blocks new database writers while it is pending,
8284** but new database readers are allowed to continue unimpeded.
8285**
8286** <dt>SQLITE_CHECKPOINT_RESTART<dd>
8287** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
8288** that after checkpointing the log file it blocks (calls the
8289** [busy-handler callback])
8290** until all readers are reading from the database file only. ^This ensures
8291** that the next writer will restart the log file from the beginning.
8292** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
8293** database writer attempts while it is pending, but does not impede readers.
8294**
8295** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
8296** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
8297** addition that it also truncates the log file to zero bytes just prior
8298** to a successful return.
8299** </dl>
8300**
8301** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
8302** the log file or to -1 if the checkpoint could not run because
8303** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
8304** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
8305** log file (including any that were already checkpointed before the function
8306** was called) or to -1 if the checkpoint could not run due to an error or
8307** because the database is not in WAL mode. ^Note that upon successful
8308** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
8309** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
8310**
8311** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
8312** any other process is running a checkpoint operation at the same time, the
8313** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
8314** busy-handler configured, it will not be invoked in this case.
8315**
8316** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
8317** exclusive "writer" lock on the database file. ^If the writer lock cannot be
8318** obtained immediately, and a busy-handler is configured, it is invoked and
8319** the writer lock retried until either the busy-handler returns 0 or the lock
8320** is successfully obtained. ^The busy-handler is also invoked while waiting for
8321** database readers as described above. ^If the busy-handler returns 0 before
8322** the writer lock is obtained or while waiting for database readers, the
8323** checkpoint operation proceeds from that point in the same way as
8324** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
8325** without blocking any further. ^SQLITE_BUSY is returned in this case.
8326**
8327** ^If parameter zDb is NULL or points to a zero length string, then the
8328** specified operation is attempted on all WAL databases [attached] to
8329** [database connection] db. In this case the
8330** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
8331** an SQLITE_BUSY error is encountered when processing one or more of the
8332** attached WAL databases, the operation is still attempted on any remaining
8333** attached databases and SQLITE_BUSY is returned at the end. ^If any other
8334** error occurs while processing an attached database, processing is abandoned
8335** and the error code is returned to the caller immediately. ^If no error
8336** (SQLITE_BUSY or otherwise) is encountered while processing the attached
8337** databases, SQLITE_OK is returned.
8338**
8339** ^If database zDb is the name of an attached database that is not in WAL
8340** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
8341** zDb is not NULL (or a zero length string) and is not the name of any
8342** attached database, SQLITE_ERROR is returned to the caller.
8343**
8344** ^Unless it returns SQLITE_MISUSE,
8345** the sqlite3_wal_checkpoint_v2() interface
8346** sets the error information that is queried by
8347** [sqlite3_errcode()] and [sqlite3_errmsg()].
8348**
8349** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
8350** from SQL.
8351*/
8352SQLITE_API int sqlite3_wal_checkpoint_v2(
8353 sqlite3 *db, /* Database handle */
8354 const char *zDb, /* Name of attached database (or NULL) */
8355 int eMode, /* SQLITE_CHECKPOINT_* value */
8356 int *pnLog, /* OUT: Size of WAL log in frames */
8357 int *pnCkpt /* OUT: Total number of frames checkpointed */
8358);
8359
8360/*
8361** CAPI3REF: Checkpoint Mode Values
8362** KEYWORDS: {checkpoint mode}
8363**
8364** These constants define all valid values for the "checkpoint mode" passed
8365** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
8366** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
8367** meaning of each of these checkpoint modes.
8368*/
8369#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */
8370#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */
8371#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */
8372#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */
8373
8374/*
8375** CAPI3REF: Virtual Table Interface Configuration
8376**
8377** This function may be called by either the [xConnect] or [xCreate] method
8378** of a [virtual table] implementation to configure
8379** various facets of the virtual table interface.
8380**
8381** If this interface is invoked outside the context of an xConnect or
8382** xCreate virtual table method then the behavior is undefined.
8383**
8384** At present, there is only one option that may be configured using
8385** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options
8386** may be added in the future.
8387*/
8388SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
8389
8390/*
8391** CAPI3REF: Virtual Table Configuration Options
8392**
8393** These macros define the various options to the
8394** [sqlite3_vtab_config()] interface that [virtual table] implementations
8395** can use to customize and optimize their behavior.
8396**
8397** <dl>
8398** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
8399** <dd>Calls of the form
8400** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
8401** where X is an integer. If X is zero, then the [virtual table] whose
8402** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
8403** support constraints. In this configuration (which is the default) if
8404** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
8405** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
8406** specified as part of the users SQL statement, regardless of the actual
8407** ON CONFLICT mode specified.
8408**
8409** If X is non-zero, then the virtual table implementation guarantees
8410** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
8411** any modifications to internal or persistent data structures have been made.
8412** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
8413** is able to roll back a statement or database transaction, and abandon
8414** or continue processing the current SQL statement as appropriate.
8415** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
8416** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
8417** had been ABORT.
8418**
8419** Virtual table implementations that are required to handle OR REPLACE
8420** must do so within the [xUpdate] method. If a call to the
8421** [sqlite3_vtab_on_conflict()] function indicates that the current ON
8422** CONFLICT policy is REPLACE, the virtual table implementation should
8423** silently replace the appropriate rows within the xUpdate callback and
8424** return SQLITE_OK. Or, if this is not possible, it may return
8425** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
8426** constraint handling.
8427** </dl>
8428*/
8429#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
8430
8431/*
8432** CAPI3REF: Determine The Virtual Table Conflict Policy
8433**
8434** This function may only be called from within a call to the [xUpdate] method
8435** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
8436** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
8437** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
8438** of the SQL statement that triggered the call to the [xUpdate] method of the
8439** [virtual table].
8440*/
8441SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
8442
8443/*
8444** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
8445**
8446** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
8447** method of a [virtual table], then it returns true if and only if the
8448** column is being fetched as part of an UPDATE operation during which the
8449** column value will not change. Applications might use this to substitute
8450** a lighter-weight value to return that the corresponding [xUpdate] method
8451** understands as a "no-change" value.
8452**
8453** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
8454** the column is not changed by the UPDATE statement, they the xColumn
8455** method can optionally return without setting a result, without calling
8456** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
8457** In that case, [sqlite3_value_nochange(X)] will return true for the
8458** same column in the [xUpdate] method.
8459*/
8460SQLITE_API int sqlite3_vtab_nochange(sqlite3_context*);
8461
8462/*
8463** CAPI3REF: Determine The Collation For a Virtual Table Constraint
8464**
8465** This function may only be called from within a call to the [xBestIndex]
8466** method of a [virtual table].
8467**
8468** The first argument must be the sqlite3_index_info object that is the
8469** first parameter to the xBestIndex() method. The second argument must be
8470** an index into the aConstraint[] array belonging to the sqlite3_index_info
8471** structure passed to xBestIndex. This function returns a pointer to a buffer
8472** containing the name of the collation sequence for the corresponding
8473** constraint.
8474*/
8475SQLITE_API SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
8476
8477/*
8478** CAPI3REF: Conflict resolution modes
8479** KEYWORDS: {conflict resolution mode}
8480**
8481** These constants are returned by [sqlite3_vtab_on_conflict()] to
8482** inform a [virtual table] implementation what the [ON CONFLICT] mode
8483** is for the SQL statement being evaluated.
8484**
8485** Note that the [SQLITE_IGNORE] constant is also used as a potential
8486** return value from the [sqlite3_set_authorizer()] callback and that
8487** [SQLITE_ABORT] is also a [result code].
8488*/
8489#define SQLITE_ROLLBACK 1
8490/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
8491#define SQLITE_FAIL 3
8492/* #define SQLITE_ABORT 4 // Also an error code */
8493#define SQLITE_REPLACE 5
8494
8495/*
8496** CAPI3REF: Prepared Statement Scan Status Opcodes
8497** KEYWORDS: {scanstatus options}
8498**
8499** The following constants can be used for the T parameter to the
8500** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a
8501** different metric for sqlite3_stmt_scanstatus() to return.
8502**
8503** When the value returned to V is a string, space to hold that string is
8504** managed by the prepared statement S and will be automatically freed when
8505** S is finalized.
8506**
8507** <dl>
8508** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
8509** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be
8510** set to the total number of times that the X-th loop has run.</dd>
8511**
8512** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
8513** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set
8514** to the total number of rows examined by all iterations of the X-th loop.</dd>
8515**
8516** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
8517** <dd>^The "double" variable pointed to by the T parameter will be set to the
8518** query planner's estimate for the average number of rows output from each
8519** iteration of the X-th loop. If the query planner's estimates was accurate,
8520** then this value will approximate the quotient NVISIT/NLOOP and the
8521** product of this value for all prior loops with the same SELECTID will
8522** be the NLOOP value for the current loop.
8523**
8524** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
8525** <dd>^The "const char *" variable pointed to by the T parameter will be set
8526** to a zero-terminated UTF-8 string containing the name of the index or table
8527** used for the X-th loop.
8528**
8529** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
8530** <dd>^The "const char *" variable pointed to by the T parameter will be set
8531** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
8532** description for the X-th loop.
8533**
8534** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
8535** <dd>^The "int" variable pointed to by the T parameter will be set to the
8536** "select-id" for the X-th loop. The select-id identifies which query or
8537** subquery the loop is part of. The main query has a select-id of zero.
8538** The select-id is the same value as is output in the first column
8539** of an [EXPLAIN QUERY PLAN] query.
8540** </dl>
8541*/
8542#define SQLITE_SCANSTAT_NLOOP 0
8543#define SQLITE_SCANSTAT_NVISIT 1
8544#define SQLITE_SCANSTAT_EST 2
8545#define SQLITE_SCANSTAT_NAME 3
8546#define SQLITE_SCANSTAT_EXPLAIN 4
8547#define SQLITE_SCANSTAT_SELECTID 5
8548
8549/*
8550** CAPI3REF: Prepared Statement Scan Status
8551** METHOD: sqlite3_stmt
8552**
8553** This interface returns information about the predicted and measured
8554** performance for pStmt. Advanced applications can use this
8555** interface to compare the predicted and the measured performance and
8556** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
8557**
8558** Since this interface is expected to be rarely used, it is only
8559** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
8560** compile-time option.
8561**
8562** The "iScanStatusOp" parameter determines which status information to return.
8563** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
8564** of this interface is undefined.
8565** ^The requested measurement is written into a variable pointed to by
8566** the "pOut" parameter.
8567** Parameter "idx" identifies the specific loop to retrieve statistics for.
8568** Loops are numbered starting from zero. ^If idx is out of range - less than
8569** zero or greater than or equal to the total number of loops used to implement
8570** the statement - a non-zero value is returned and the variable that pOut
8571** points to is unchanged.
8572**
8573** ^Statistics might not be available for all loops in all statements. ^In cases
8574** where there exist loops with no available statistics, this function behaves
8575** as if the loop did not exist - it returns non-zero and leave the variable
8576** that pOut points to unchanged.
8577**
8578** See also: [sqlite3_stmt_scanstatus_reset()]
8579*/
8580SQLITE_API int sqlite3_stmt_scanstatus(
8581 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */
8582 int idx, /* Index of loop to report on */
8583 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */
8584 void *pOut /* Result written here */
8585);
8586
8587/*
8588** CAPI3REF: Zero Scan-Status Counters
8589** METHOD: sqlite3_stmt
8590**
8591** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
8592**
8593** This API is only available if the library is built with pre-processor
8594** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
8595*/
8596SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
8597
8598/*
8599** CAPI3REF: Flush caches to disk mid-transaction
8600**
8601** ^If a write-transaction is open on [database connection] D when the
8602** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
8603** pages in the pager-cache that are not currently in use are written out
8604** to disk. A dirty page may be in use if a database cursor created by an
8605** active SQL statement is reading from it, or if it is page 1 of a database
8606** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)]
8607** interface flushes caches for all schemas - "main", "temp", and
8608** any [attached] databases.
8609**
8610** ^If this function needs to obtain extra database locks before dirty pages
8611** can be flushed to disk, it does so. ^If those locks cannot be obtained
8612** immediately and there is a busy-handler callback configured, it is invoked
8613** in the usual manner. ^If the required lock still cannot be obtained, then
8614** the database is skipped and an attempt made to flush any dirty pages
8615** belonging to the next (if any) database. ^If any databases are skipped
8616** because locks cannot be obtained, but no other error occurs, this
8617** function returns SQLITE_BUSY.
8618**
8619** ^If any other error occurs while flushing dirty pages to disk (for
8620** example an IO error or out-of-memory condition), then processing is
8621** abandoned and an SQLite [error code] is returned to the caller immediately.
8622**
8623** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
8624**
8625** ^This function does not set the database handle error code or message
8626** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
8627*/
8628SQLITE_API int sqlite3_db_cacheflush(sqlite3*);
8629
8630/*
8631** CAPI3REF: The pre-update hook.
8632**
8633** ^These interfaces are only available if SQLite is compiled using the
8634** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
8635**
8636** ^The [sqlite3_preupdate_hook()] interface registers a callback function
8637** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
8638** on a database table.
8639** ^At most one preupdate hook may be registered at a time on a single
8640** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
8641** the previous setting.
8642** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
8643** with a NULL pointer as the second parameter.
8644** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
8645** the first parameter to callbacks.
8646**
8647** ^The preupdate hook only fires for changes to real database tables; the
8648** preupdate hook is not invoked for changes to [virtual tables] or to
8649** system tables like sqlite_master or sqlite_stat1.
8650**
8651** ^The second parameter to the preupdate callback is a pointer to
8652** the [database connection] that registered the preupdate hook.
8653** ^The third parameter to the preupdate callback is one of the constants
8654** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
8655** kind of update operation that is about to occur.
8656** ^(The fourth parameter to the preupdate callback is the name of the
8657** database within the database connection that is being modified. This
8658** will be "main" for the main database or "temp" for TEMP tables or
8659** the name given after the AS keyword in the [ATTACH] statement for attached
8660** databases.)^
8661** ^The fifth parameter to the preupdate callback is the name of the
8662** table that is being modified.
8663**
8664** For an UPDATE or DELETE operation on a [rowid table], the sixth
8665** parameter passed to the preupdate callback is the initial [rowid] of the
8666** row being modified or deleted. For an INSERT operation on a rowid table,
8667** or any operation on a WITHOUT ROWID table, the value of the sixth
8668** parameter is undefined. For an INSERT or UPDATE on a rowid table the
8669** seventh parameter is the final rowid value of the row being inserted
8670** or updated. The value of the seventh parameter passed to the callback
8671** function is not defined for operations on WITHOUT ROWID tables, or for
8672** INSERT operations on rowid tables.
8673**
8674** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
8675** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
8676** provide additional information about a preupdate event. These routines
8677** may only be called from within a preupdate callback. Invoking any of
8678** these routines from outside of a preupdate callback or with a
8679** [database connection] pointer that is different from the one supplied
8680** to the preupdate callback results in undefined and probably undesirable
8681** behavior.
8682**
8683** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
8684** in the row that is being inserted, updated, or deleted.
8685**
8686** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
8687** a [protected sqlite3_value] that contains the value of the Nth column of
8688** the table row before it is updated. The N parameter must be between 0
8689** and one less than the number of columns or the behavior will be
8690** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
8691** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
8692** behavior is undefined. The [sqlite3_value] that P points to
8693** will be destroyed when the preupdate callback returns.
8694**
8695** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
8696** a [protected sqlite3_value] that contains the value of the Nth column of
8697** the table row after it is updated. The N parameter must be between 0
8698** and one less than the number of columns or the behavior will be
8699** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
8700** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
8701** behavior is undefined. The [sqlite3_value] that P points to
8702** will be destroyed when the preupdate callback returns.
8703**
8704** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
8705** callback was invoked as a result of a direct insert, update, or delete
8706** operation; or 1 for inserts, updates, or deletes invoked by top-level
8707** triggers; or 2 for changes resulting from triggers called by top-level
8708** triggers; and so forth.
8709**
8710** See also: [sqlite3_update_hook()]
8711*/
8712#if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
8713SQLITE_API void *sqlite3_preupdate_hook(
8714 sqlite3 *db,
8715 void(*xPreUpdate)(
8716 void *pCtx, /* Copy of third arg to preupdate_hook() */
8717 sqlite3 *db, /* Database handle */
8718 int op, /* SQLITE_UPDATE, DELETE or INSERT */
8719 char const *zDb, /* Database name */
8720 char const *zName, /* Table name */
8721 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */
8722 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */
8723 ),
8724 void*
8725);
8726SQLITE_API int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
8727SQLITE_API int sqlite3_preupdate_count(sqlite3 *);
8728SQLITE_API int sqlite3_preupdate_depth(sqlite3 *);
8729SQLITE_API int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
8730#endif
8731
8732/*
8733** CAPI3REF: Low-level system error code
8734**
8735** ^Attempt to return the underlying operating system error code or error
8736** number that caused the most recent I/O error or failure to open a file.
8737** The return value is OS-dependent. For example, on unix systems, after
8738** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
8739** called to get back the underlying "errno" that caused the problem, such
8740** as ENOSPC, EAUTH, EISDIR, and so forth.
8741*/
8742SQLITE_API int sqlite3_system_errno(sqlite3*);
8743
8744/*
8745** CAPI3REF: Database Snapshot
8746** KEYWORDS: {snapshot} {sqlite3_snapshot}
8747** EXPERIMENTAL
8748**
8749** An instance of the snapshot object records the state of a [WAL mode]
8750** database for some specific point in history.
8751**
8752** In [WAL mode], multiple [database connections] that are open on the
8753** same database file can each be reading a different historical version
8754** of the database file. When a [database connection] begins a read
8755** transaction, that connection sees an unchanging copy of the database
8756** as it existed for the point in time when the transaction first started.
8757** Subsequent changes to the database from other connections are not seen
8758** by the reader until a new read transaction is started.
8759**
8760** The sqlite3_snapshot object records state information about an historical
8761** version of the database file so that it is possible to later open a new read
8762** transaction that sees that historical version of the database rather than
8763** the most recent version.
8764**
8765** The constructor for this object is [sqlite3_snapshot_get()]. The
8766** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer
8767** to an historical snapshot (if possible). The destructor for
8768** sqlite3_snapshot objects is [sqlite3_snapshot_free()].
8769*/
8770typedef struct sqlite3_snapshot {
8771 unsigned char hidden[48];
8772} sqlite3_snapshot;
8773
8774/*
8775** CAPI3REF: Record A Database Snapshot
8776** EXPERIMENTAL
8777**
8778** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
8779** new [sqlite3_snapshot] object that records the current state of
8780** schema S in database connection D. ^On success, the
8781** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
8782** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
8783** If there is not already a read-transaction open on schema S when
8784** this function is called, one is opened automatically.
8785**
8786** The following must be true for this function to succeed. If any of
8787** the following statements are false when sqlite3_snapshot_get() is
8788** called, SQLITE_ERROR is returned. The final value of *P is undefined
8789** in this case.
8790**
8791** <ul>
8792** <li> The database handle must be in [autocommit mode].
8793**
8794** <li> Schema S of [database connection] D must be a [WAL mode] database.
8795**
8796** <li> There must not be a write transaction open on schema S of database
8797** connection D.
8798**
8799** <li> One or more transactions must have been written to the current wal
8800** file since it was created on disk (by any connection). This means
8801** that a snapshot cannot be taken on a wal mode database with no wal
8802** file immediately after it is first opened. At least one transaction
8803** must be written to it first.
8804** </ul>
8805**
8806** This function may also return SQLITE_NOMEM. If it is called with the
8807** database handle in autocommit mode but fails for some other reason,
8808** whether or not a read transaction is opened on schema S is undefined.
8809**
8810** The [sqlite3_snapshot] object returned from a successful call to
8811** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
8812** to avoid a memory leak.
8813**
8814** The [sqlite3_snapshot_get()] interface is only available when the
8815** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
8816*/
8817SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
8818 sqlite3 *db,
8819 const char *zSchema,
8820 sqlite3_snapshot **ppSnapshot
8821);
8822
8823/*
8824** CAPI3REF: Start a read transaction on an historical snapshot
8825** EXPERIMENTAL
8826**
8827** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a
8828** read transaction for schema S of
8829** [database connection] D such that the read transaction
8830** refers to historical [snapshot] P, rather than the most
8831** recent change to the database.
8832** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success
8833** or an appropriate [error code] if it fails.
8834**
8835** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be
8836** the first operation following the [BEGIN] that takes the schema S
8837** out of [autocommit mode].
8838** ^In other words, schema S must not currently be in
8839** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the
8840** database connection D must be out of [autocommit mode].
8841** ^A [snapshot] will fail to open if it has been overwritten by a
8842** [checkpoint].
8843** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
8844** database connection D does not know that the database file for
8845** schema S is in [WAL mode]. A database connection might not know
8846** that the database file is in [WAL mode] if there has been no prior
8847** I/O on that database connection, or if the database entered [WAL mode]
8848** after the most recent I/O on the database connection.)^
8849** (Hint: Run "[PRAGMA application_id]" against a newly opened
8850** database connection in order to make it ready to use snapshots.)
8851**
8852** The [sqlite3_snapshot_open()] interface is only available when the
8853** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
8854*/
8855SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
8856 sqlite3 *db,
8857 const char *zSchema,
8858 sqlite3_snapshot *pSnapshot
8859);
8860
8861/*
8862** CAPI3REF: Destroy a snapshot
8863** EXPERIMENTAL
8864**
8865** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
8866** The application must eventually free every [sqlite3_snapshot] object
8867** using this routine to avoid a memory leak.
8868**
8869** The [sqlite3_snapshot_free()] interface is only available when the
8870** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
8871*/
8872SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
8873
8874/*
8875** CAPI3REF: Compare the ages of two snapshot handles.
8876** EXPERIMENTAL
8877**
8878** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
8879** of two valid snapshot handles.
8880**
8881** If the two snapshot handles are not associated with the same database
8882** file, the result of the comparison is undefined.
8883**
8884** Additionally, the result of the comparison is only valid if both of the
8885** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
8886** last time the wal file was deleted. The wal file is deleted when the
8887** database is changed back to rollback mode or when the number of database
8888** clients drops to zero. If either snapshot handle was obtained before the
8889** wal file was last deleted, the value returned by this function
8890** is undefined.
8891**
8892** Otherwise, this API returns a negative value if P1 refers to an older
8893** snapshot than P2, zero if the two handles refer to the same database
8894** snapshot, and a positive value if P1 is a newer snapshot than P2.
8895*/
8896SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
8897 sqlite3_snapshot *p1,
8898 sqlite3_snapshot *p2
8899);
8900
8901/*
8902** CAPI3REF: Recover snapshots from a wal file
8903** EXPERIMENTAL
8904**
8905** If all connections disconnect from a database file but do not perform
8906** a checkpoint, the existing wal file is opened along with the database
8907** file the next time the database is opened. At this point it is only
8908** possible to successfully call sqlite3_snapshot_open() to open the most
8909** recent snapshot of the database (the one at the head of the wal file),
8910** even though the wal file may contain other valid snapshots for which
8911** clients have sqlite3_snapshot handles.
8912**
8913** This function attempts to scan the wal file associated with database zDb
8914** of database handle db and make all valid snapshots available to
8915** sqlite3_snapshot_open(). It is an error if there is already a read
8916** transaction open on the database, or if the database is not a wal mode
8917** database.
8918**
8919** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
8920*/
8921SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
8922
8923/*
8924** Undo the hack that converts floating point types to integer for
8925** builds on processors without floating point support.
8926*/
8927#ifdef SQLITE_OMIT_FLOATING_POINT
8928# undef double
8929#endif
8930
8931#ifdef __cplusplus
8932} /* End of the 'extern "C"' block */
8933#endif
8934#endif /* SQLITE3_H */
8935
8936/******** Begin file sqlite3rtree.h *********/
8937/*
8938** 2010 August 30
8939**
8940** The author disclaims copyright to this source code. In place of
8941** a legal notice, here is a blessing:
8942**
8943** May you do good and not evil.
8944** May you find forgiveness for yourself and forgive others.
8945** May you share freely, never taking more than you give.
8946**
8947*************************************************************************
8948*/
8949
8950#ifndef _SQLITE3RTREE_H_
8951#define _SQLITE3RTREE_H_
8952
8953
8954#ifdef __cplusplus
8955extern "C" {
8956#endif
8957
8958typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
8959typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
8960
8961/* The double-precision datatype used by RTree depends on the
8962** SQLITE_RTREE_INT_ONLY compile-time option.
8963*/
8964#ifdef SQLITE_RTREE_INT_ONLY
8965 typedef sqlite3_int64 sqlite3_rtree_dbl;
8966#else
8967 typedef double sqlite3_rtree_dbl;
8968#endif
8969
8970/*
8971** Register a geometry callback named zGeom that can be used as part of an
8972** R-Tree geometry query as follows:
8973**
8974** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
8975*/
8976SQLITE_API int sqlite3_rtree_geometry_callback(
8977 sqlite3 *db,
8978 const char *zGeom,
8979 int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
8980 void *pContext
8981);
8982
8983
8984/*
8985** A pointer to a structure of the following type is passed as the first
8986** argument to callbacks registered using rtree_geometry_callback().
8987*/
8988struct sqlite3_rtree_geometry {
8989 void *pContext; /* Copy of pContext passed to s_r_g_c() */
8990 int nParam; /* Size of array aParam[] */
8991 sqlite3_rtree_dbl *aParam; /* Parameters passed to SQL geom function */
8992 void *pUser; /* Callback implementation user data */
8993 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */
8994};
8995
8996/*
8997** Register a 2nd-generation geometry callback named zScore that can be
8998** used as part of an R-Tree geometry query as follows:
8999**
9000** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
9001*/
9002SQLITE_API int sqlite3_rtree_query_callback(
9003 sqlite3 *db,
9004 const char *zQueryFunc,
9005 int (*xQueryFunc)(sqlite3_rtree_query_info*),
9006 void *pContext,
9007 void (*xDestructor)(void*)
9008);
9009
9010
9011/*
9012** A pointer to a structure of the following type is passed as the
9013** argument to scored geometry callback registered using
9014** sqlite3_rtree_query_callback().
9015**
9016** Note that the first 5 fields of this structure are identical to
9017** sqlite3_rtree_geometry. This structure is a subclass of
9018** sqlite3_rtree_geometry.
9019*/
9020struct sqlite3_rtree_query_info {
9021 void *pContext; /* pContext from when function registered */
9022 int nParam; /* Number of function parameters */
9023 sqlite3_rtree_dbl *aParam; /* value of function parameters */
9024 void *pUser; /* callback can use this, if desired */
9025 void (*xDelUser)(void*); /* function to free pUser */
9026 sqlite3_rtree_dbl *aCoord; /* Coordinates of node or entry to check */
9027 unsigned int *anQueue; /* Number of pending entries in the queue */
9028 int nCoord; /* Number of coordinates */
9029 int iLevel; /* Level of current node or entry */
9030 int mxLevel; /* The largest iLevel value in the tree */
9031 sqlite3_int64 iRowid; /* Rowid for current entry */
9032 sqlite3_rtree_dbl rParentScore; /* Score of parent node */
9033 int eParentWithin; /* Visibility of parent node */
9034 int eWithin; /* OUT: Visiblity */
9035 sqlite3_rtree_dbl rScore; /* OUT: Write the score here */
9036 /* The following fields are only available in 3.8.11 and later */
9037 sqlite3_value **apSqlParam; /* Original SQL values of parameters */
9038};
9039
9040/*
9041** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
9042*/
9043#define NOT_WITHIN 0 /* Object completely outside of query region */
9044#define PARTLY_WITHIN 1 /* Object partially overlaps query region */
9045#define FULLY_WITHIN 2 /* Object fully contained within query region */
9046
9047
9048#ifdef __cplusplus
9049} /* end of the 'extern "C"' block */
9050#endif
9051
9052#endif /* ifndef _SQLITE3RTREE_H_ */
9053
9054/******** End of sqlite3rtree.h *********/
9055/******** Begin file sqlite3session.h *********/
9056
9057#if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
9058#define __SQLITESESSION_H_ 1
9059
9060/*
9061** Make sure we can call this stuff from C++.
9062*/
9063#ifdef __cplusplus
9064extern "C" {
9065#endif
9066
9067
9068/*
9069** CAPI3REF: Session Object Handle
9070*/
9071typedef struct sqlite3_session sqlite3_session;
9072
9073/*
9074** CAPI3REF: Changeset Iterator Handle
9075*/
9076typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
9077
9078/*
9079** CAPI3REF: Create A New Session Object
9080**
9081** Create a new session object attached to database handle db. If successful,
9082** a pointer to the new object is written to *ppSession and SQLITE_OK is
9083** returned. If an error occurs, *ppSession is set to NULL and an SQLite
9084** error code (e.g. SQLITE_NOMEM) is returned.
9085**
9086** It is possible to create multiple session objects attached to a single
9087** database handle.
9088**
9089** Session objects created using this function should be deleted using the
9090** [sqlite3session_delete()] function before the database handle that they
9091** are attached to is itself closed. If the database handle is closed before
9092** the session object is deleted, then the results of calling any session
9093** module function, including [sqlite3session_delete()] on the session object
9094** are undefined.
9095**
9096** Because the session module uses the [sqlite3_preupdate_hook()] API, it
9097** is not possible for an application to register a pre-update hook on a
9098** database handle that has one or more session objects attached. Nor is
9099** it possible to create a session object attached to a database handle for
9100** which a pre-update hook is already defined. The results of attempting
9101** either of these things are undefined.
9102**
9103** The session object will be used to create changesets for tables in
9104** database zDb, where zDb is either "main", or "temp", or the name of an
9105** attached database. It is not an error if database zDb is not attached
9106** to the database when the session object is created.
9107*/
9108SQLITE_API int sqlite3session_create(
9109 sqlite3 *db, /* Database handle */
9110 const char *zDb, /* Name of db (e.g. "main") */
9111 sqlite3_session **ppSession /* OUT: New session object */
9112);
9113
9114/*
9115** CAPI3REF: Delete A Session Object
9116**
9117** Delete a session object previously allocated using
9118** [sqlite3session_create()]. Once a session object has been deleted, the
9119** results of attempting to use pSession with any other session module
9120** function are undefined.
9121**
9122** Session objects must be deleted before the database handle to which they
9123** are attached is closed. Refer to the documentation for
9124** [sqlite3session_create()] for details.
9125*/
9126SQLITE_API void sqlite3session_delete(sqlite3_session *pSession);
9127
9128
9129/*
9130** CAPI3REF: Enable Or Disable A Session Object
9131**
9132** Enable or disable the recording of changes by a session object. When
9133** enabled, a session object records changes made to the database. When
9134** disabled - it does not. A newly created session object is enabled.
9135** Refer to the documentation for [sqlite3session_changeset()] for further
9136** details regarding how enabling and disabling a session object affects
9137** the eventual changesets.
9138**
9139** Passing zero to this function disables the session. Passing a value
9140** greater than zero enables it. Passing a value less than zero is a
9141** no-op, and may be used to query the current state of the session.
9142**
9143** The return value indicates the final state of the session object: 0 if
9144** the session is disabled, or 1 if it is enabled.
9145*/
9146SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable);
9147
9148/*
9149** CAPI3REF: Set Or Clear the Indirect Change Flag
9150**
9151** Each change recorded by a session object is marked as either direct or
9152** indirect. A change is marked as indirect if either:
9153**
9154** <ul>
9155** <li> The session object "indirect" flag is set when the change is
9156** made, or
9157** <li> The change is made by an SQL trigger or foreign key action
9158** instead of directly as a result of a users SQL statement.
9159** </ul>
9160**
9161** If a single row is affected by more than one operation within a session,
9162** then the change is considered indirect if all operations meet the criteria
9163** for an indirect change above, or direct otherwise.
9164**
9165** This function is used to set, clear or query the session object indirect
9166** flag. If the second argument passed to this function is zero, then the
9167** indirect flag is cleared. If it is greater than zero, the indirect flag
9168** is set. Passing a value less than zero does not modify the current value
9169** of the indirect flag, and may be used to query the current state of the
9170** indirect flag for the specified session object.
9171**
9172** The return value indicates the final state of the indirect flag: 0 if
9173** it is clear, or 1 if it is set.
9174*/
9175SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect);
9176
9177/*
9178** CAPI3REF: Attach A Table To A Session Object
9179**
9180** If argument zTab is not NULL, then it is the name of a table to attach
9181** to the session object passed as the first argument. All subsequent changes
9182** made to the table while the session object is enabled will be recorded. See
9183** documentation for [sqlite3session_changeset()] for further details.
9184**
9185** Or, if argument zTab is NULL, then changes are recorded for all tables
9186** in the database. If additional tables are added to the database (by
9187** executing "CREATE TABLE" statements) after this call is made, changes for
9188** the new tables are also recorded.
9189**
9190** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
9191** defined as part of their CREATE TABLE statement. It does not matter if the
9192** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
9193** KEY may consist of a single column, or may be a composite key.
9194**
9195** It is not an error if the named table does not exist in the database. Nor
9196** is it an error if the named table does not have a PRIMARY KEY. However,
9197** no changes will be recorded in either of these scenarios.
9198**
9199** Changes are not recorded for individual rows that have NULL values stored
9200** in one or more of their PRIMARY KEY columns.
9201**
9202** SQLITE_OK is returned if the call completes without error. Or, if an error
9203** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
9204**
9205** <h3>Special sqlite_stat1 Handling</h3>
9206**
9207** As of SQLite version 3.22.0, the "sqlite_stat1" table is an exception to
9208** some of the rules above. In SQLite, the schema of sqlite_stat1 is:
9209** <pre>
9210** &nbsp; CREATE TABLE sqlite_stat1(tbl,idx,stat)
9211** </pre>
9212**
9213** Even though sqlite_stat1 does not have a PRIMARY KEY, changes are
9214** recorded for it as if the PRIMARY KEY is (tbl,idx). Additionally, changes
9215** are recorded for rows for which (idx IS NULL) is true. However, for such
9216** rows a zero-length blob (SQL value X'') is stored in the changeset or
9217** patchset instead of a NULL value. This allows such changesets to be
9218** manipulated by legacy implementations of sqlite3changeset_invert(),
9219** concat() and similar.
9220**
9221** The sqlite3changeset_apply() function automatically converts the
9222** zero-length blob back to a NULL value when updating the sqlite_stat1
9223** table. However, if the application calls sqlite3changeset_new(),
9224** sqlite3changeset_old() or sqlite3changeset_conflict on a changeset
9225** iterator directly (including on a changeset iterator passed to a
9226** conflict-handler callback) then the X'' value is returned. The application
9227** must translate X'' to NULL itself if required.
9228**
9229** Legacy (older than 3.22.0) versions of the sessions module cannot capture
9230** changes made to the sqlite_stat1 table. Legacy versions of the
9231** sqlite3changeset_apply() function silently ignore any modifications to the
9232** sqlite_stat1 table that are part of a changeset or patchset.
9233*/
9234SQLITE_API int sqlite3session_attach(
9235 sqlite3_session *pSession, /* Session object */
9236 const char *zTab /* Table name */
9237);
9238
9239/*
9240** CAPI3REF: Set a table filter on a Session Object.
9241**
9242** The second argument (xFilter) is the "filter callback". For changes to rows
9243** in tables that are not attached to the Session object, the filter is called
9244** to determine whether changes to the table's rows should be tracked or not.
9245** If xFilter returns 0, changes is not tracked. Note that once a table is
9246** attached, xFilter will not be called again.
9247*/
9248SQLITE_API void sqlite3session_table_filter(
9249 sqlite3_session *pSession, /* Session object */
9250 int(*xFilter)(
9251 void *pCtx, /* Copy of third arg to _filter_table() */
9252 const char *zTab /* Table name */
9253 ),
9254 void *pCtx /* First argument passed to xFilter */
9255);
9256
9257/*
9258** CAPI3REF: Generate A Changeset From A Session Object
9259**
9260** Obtain a changeset containing changes to the tables attached to the
9261** session object passed as the first argument. If successful,
9262** set *ppChangeset to point to a buffer containing the changeset
9263** and *pnChangeset to the size of the changeset in bytes before returning
9264** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
9265** zero and return an SQLite error code.
9266**
9267** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
9268** each representing a change to a single row of an attached table. An INSERT
9269** change contains the values of each field of a new database row. A DELETE
9270** contains the original values of each field of a deleted database row. An
9271** UPDATE change contains the original values of each field of an updated
9272** database row along with the updated values for each updated non-primary-key
9273** column. It is not possible for an UPDATE change to represent a change that
9274** modifies the values of primary key columns. If such a change is made, it
9275** is represented in a changeset as a DELETE followed by an INSERT.
9276**
9277** Changes are not recorded for rows that have NULL values stored in one or
9278** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
9279** no corresponding change is present in the changesets returned by this
9280** function. If an existing row with one or more NULL values stored in
9281** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
9282** only an INSERT is appears in the changeset. Similarly, if an existing row
9283** with non-NULL PRIMARY KEY values is updated so that one or more of its
9284** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
9285** DELETE change only.
9286**
9287** The contents of a changeset may be traversed using an iterator created
9288** using the [sqlite3changeset_start()] API. A changeset may be applied to
9289** a database with a compatible schema using the [sqlite3changeset_apply()]
9290** API.
9291**
9292** Within a changeset generated by this function, all changes related to a
9293** single table are grouped together. In other words, when iterating through
9294** a changeset or when applying a changeset to a database, all changes related
9295** to a single table are processed before moving on to the next table. Tables
9296** are sorted in the same order in which they were attached (or auto-attached)
9297** to the sqlite3_session object. The order in which the changes related to
9298** a single table are stored is undefined.
9299**
9300** Following a successful call to this function, it is the responsibility of
9301** the caller to eventually free the buffer that *ppChangeset points to using
9302** [sqlite3_free()].
9303**
9304** <h3>Changeset Generation</h3>
9305**
9306** Once a table has been attached to a session object, the session object
9307** records the primary key values of all new rows inserted into the table.
9308** It also records the original primary key and other column values of any
9309** deleted or updated rows. For each unique primary key value, data is only
9310** recorded once - the first time a row with said primary key is inserted,
9311** updated or deleted in the lifetime of the session.
9312**
9313** There is one exception to the previous paragraph: when a row is inserted,
9314** updated or deleted, if one or more of its primary key columns contain a
9315** NULL value, no record of the change is made.
9316**
9317** The session object therefore accumulates two types of records - those
9318** that consist of primary key values only (created when the user inserts
9319** a new record) and those that consist of the primary key values and the
9320** original values of other table columns (created when the users deletes
9321** or updates a record).
9322**
9323** When this function is called, the requested changeset is created using
9324** both the accumulated records and the current contents of the database
9325** file. Specifically:
9326**
9327** <ul>
9328** <li> For each record generated by an insert, the database is queried
9329** for a row with a matching primary key. If one is found, an INSERT
9330** change is added to the changeset. If no such row is found, no change
9331** is added to the changeset.
9332**
9333** <li> For each record generated by an update or delete, the database is
9334** queried for a row with a matching primary key. If such a row is
9335** found and one or more of the non-primary key fields have been
9336** modified from their original values, an UPDATE change is added to
9337** the changeset. Or, if no such row is found in the table, a DELETE
9338** change is added to the changeset. If there is a row with a matching
9339** primary key in the database, but all fields contain their original
9340** values, no change is added to the changeset.
9341** </ul>
9342**
9343** This means, amongst other things, that if a row is inserted and then later
9344** deleted while a session object is active, neither the insert nor the delete
9345** will be present in the changeset. Or if a row is deleted and then later a
9346** row with the same primary key values inserted while a session object is
9347** active, the resulting changeset will contain an UPDATE change instead of
9348** a DELETE and an INSERT.
9349**
9350** When a session object is disabled (see the [sqlite3session_enable()] API),
9351** it does not accumulate records when rows are inserted, updated or deleted.
9352** This may appear to have some counter-intuitive effects if a single row
9353** is written to more than once during a session. For example, if a row
9354** is inserted while a session object is enabled, then later deleted while
9355** the same session object is disabled, no INSERT record will appear in the
9356** changeset, even though the delete took place while the session was disabled.
9357** Or, if one field of a row is updated while a session is disabled, and
9358** another field of the same row is updated while the session is enabled, the
9359** resulting changeset will contain an UPDATE change that updates both fields.
9360*/
9361SQLITE_API int sqlite3session_changeset(
9362 sqlite3_session *pSession, /* Session object */
9363 int *pnChangeset, /* OUT: Size of buffer at *ppChangeset */
9364 void **ppChangeset /* OUT: Buffer containing changeset */
9365);
9366
9367/*
9368** CAPI3REF: Load The Difference Between Tables Into A Session
9369**
9370** If it is not already attached to the session object passed as the first
9371** argument, this function attaches table zTbl in the same manner as the
9372** [sqlite3session_attach()] function. If zTbl does not exist, or if it
9373** does not have a primary key, this function is a no-op (but does not return
9374** an error).
9375**
9376** Argument zFromDb must be the name of a database ("main", "temp" etc.)
9377** attached to the same database handle as the session object that contains
9378** a table compatible with the table attached to the session by this function.
9379** A table is considered compatible if it:
9380**
9381** <ul>
9382** <li> Has the same name,
9383** <li> Has the same set of columns declared in the same order, and
9384** <li> Has the same PRIMARY KEY definition.
9385** </ul>
9386**
9387** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
9388** are compatible but do not have any PRIMARY KEY columns, it is not an error
9389** but no changes are added to the session object. As with other session
9390** APIs, tables without PRIMARY KEYs are simply ignored.
9391**
9392** This function adds a set of changes to the session object that could be
9393** used to update the table in database zFrom (call this the "from-table")
9394** so that its content is the same as the table attached to the session
9395** object (call this the "to-table"). Specifically:
9396**
9397** <ul>
9398** <li> For each row (primary key) that exists in the to-table but not in
9399** the from-table, an INSERT record is added to the session object.
9400**
9401** <li> For each row (primary key) that exists in the to-table but not in
9402** the from-table, a DELETE record is added to the session object.
9403**
9404** <li> For each row (primary key) that exists in both tables, but features
9405** different non-PK values in each, an UPDATE record is added to the
9406** session.
9407** </ul>
9408**
9409** To clarify, if this function is called and then a changeset constructed
9410** using [sqlite3session_changeset()], then after applying that changeset to
9411** database zFrom the contents of the two compatible tables would be
9412** identical.
9413**
9414** It an error if database zFrom does not exist or does not contain the
9415** required compatible table.
9416**
9417** If the operation successful, SQLITE_OK is returned. Otherwise, an SQLite
9418** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
9419** may be set to point to a buffer containing an English language error
9420** message. It is the responsibility of the caller to free this buffer using
9421** sqlite3_free().
9422*/
9423SQLITE_API int sqlite3session_diff(
9424 sqlite3_session *pSession,
9425 const char *zFromDb,
9426 const char *zTbl,
9427 char **pzErrMsg
9428);
9429
9430
9431/*
9432** CAPI3REF: Generate A Patchset From A Session Object
9433**
9434** The differences between a patchset and a changeset are that:
9435**
9436** <ul>
9437** <li> DELETE records consist of the primary key fields only. The
9438** original values of other fields are omitted.
9439** <li> The original values of any modified fields are omitted from
9440** UPDATE records.
9441** </ul>
9442**
9443** A patchset blob may be used with up to date versions of all
9444** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(),
9445** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
9446** attempting to use a patchset blob with old versions of the
9447** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error.
9448**
9449** Because the non-primary key "old.*" fields are omitted, no
9450** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
9451** is passed to the sqlite3changeset_apply() API. Other conflict types work
9452** in the same way as for changesets.
9453**
9454** Changes within a patchset are ordered in the same way as for changesets
9455** generated by the sqlite3session_changeset() function (i.e. all changes for
9456** a single table are grouped together, tables appear in the order in which
9457** they were attached to the session object).
9458*/
9459SQLITE_API int sqlite3session_patchset(
9460 sqlite3_session *pSession, /* Session object */
9461 int *pnPatchset, /* OUT: Size of buffer at *ppPatchset */
9462 void **ppPatchset /* OUT: Buffer containing patchset */
9463);
9464
9465/*
9466** CAPI3REF: Test if a changeset has recorded any changes.
9467**
9468** Return non-zero if no changes to attached tables have been recorded by
9469** the session object passed as the first argument. Otherwise, if one or
9470** more changes have been recorded, return zero.
9471**
9472** Even if this function returns zero, it is possible that calling
9473** [sqlite3session_changeset()] on the session handle may still return a
9474** changeset that contains no changes. This can happen when a row in
9475** an attached table is modified and then later on the original values
9476** are restored. However, if this function returns non-zero, then it is
9477** guaranteed that a call to sqlite3session_changeset() will return a
9478** changeset containing zero changes.
9479*/
9480SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);
9481
9482/*
9483** CAPI3REF: Create An Iterator To Traverse A Changeset
9484**
9485** Create an iterator used to iterate through the contents of a changeset.
9486** If successful, *pp is set to point to the iterator handle and SQLITE_OK
9487** is returned. Otherwise, if an error occurs, *pp is set to zero and an
9488** SQLite error code is returned.
9489**
9490** The following functions can be used to advance and query a changeset
9491** iterator created by this function:
9492**
9493** <ul>
9494** <li> [sqlite3changeset_next()]
9495** <li> [sqlite3changeset_op()]
9496** <li> [sqlite3changeset_new()]
9497** <li> [sqlite3changeset_old()]
9498** </ul>
9499**
9500** It is the responsibility of the caller to eventually destroy the iterator
9501** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
9502** changeset (pChangeset) must remain valid until after the iterator is
9503** destroyed.
9504**
9505** Assuming the changeset blob was created by one of the
9506** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
9507** [sqlite3changeset_invert()] functions, all changes within the changeset
9508** that apply to a single table are grouped together. This means that when
9509** an application iterates through a changeset using an iterator created by
9510** this function, all changes that relate to a single table are visited
9511** consecutively. There is no chance that the iterator will visit a change
9512** the applies to table X, then one for table Y, and then later on visit
9513** another change for table X.
9514*/
9515SQLITE_API int sqlite3changeset_start(
9516 sqlite3_changeset_iter **pp, /* OUT: New changeset iterator handle */
9517 int nChangeset, /* Size of changeset blob in bytes */
9518 void *pChangeset /* Pointer to blob containing changeset */
9519);
9520
9521
9522/*
9523** CAPI3REF: Advance A Changeset Iterator
9524**
9525** This function may only be used with iterators created by function
9526** [sqlite3changeset_start()]. If it is called on an iterator passed to
9527** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
9528** is returned and the call has no effect.
9529**
9530** Immediately after an iterator is created by sqlite3changeset_start(), it
9531** does not point to any change in the changeset. Assuming the changeset
9532** is not empty, the first call to this function advances the iterator to
9533** point to the first change in the changeset. Each subsequent call advances
9534** the iterator to point to the next change in the changeset (if any). If
9535** no error occurs and the iterator points to a valid change after a call
9536** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned.
9537** Otherwise, if all changes in the changeset have already been visited,
9538** SQLITE_DONE is returned.
9539**
9540** If an error occurs, an SQLite error code is returned. Possible error
9541** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or
9542** SQLITE_NOMEM.
9543*/
9544SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *pIter);
9545
9546/*
9547** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
9548**
9549** The pIter argument passed to this function may either be an iterator
9550** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
9551** created by [sqlite3changeset_start()]. In the latter case, the most recent
9552** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
9553** is not the case, this function returns [SQLITE_MISUSE].
9554**
9555** If argument pzTab is not NULL, then *pzTab is set to point to a
9556** nul-terminated utf-8 encoded string containing the name of the table
9557** affected by the current change. The buffer remains valid until either
9558** sqlite3changeset_next() is called on the iterator or until the
9559** conflict-handler function returns. If pnCol is not NULL, then *pnCol is
9560** set to the number of columns in the table affected by the change. If
9561** pbIncorrect is not NULL, then *pbIndirect is set to true (1) if the change
9562** is an indirect change, or false (0) otherwise. See the documentation for
9563** [sqlite3session_indirect()] for a description of direct and indirect
9564** changes. Finally, if pOp is not NULL, then *pOp is set to one of
9565** [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE], depending on the
9566** type of change that the iterator currently points to.
9567**
9568** If no error occurs, SQLITE_OK is returned. If an error does occur, an
9569** SQLite error code is returned. The values of the output variables may not
9570** be trusted in this case.
9571*/
9572SQLITE_API int sqlite3changeset_op(
9573 sqlite3_changeset_iter *pIter, /* Iterator object */
9574 const char **pzTab, /* OUT: Pointer to table name */
9575 int *pnCol, /* OUT: Number of columns in table */
9576 int *pOp, /* OUT: SQLITE_INSERT, DELETE or UPDATE */
9577 int *pbIndirect /* OUT: True for an 'indirect' change */
9578);
9579
9580/*
9581** CAPI3REF: Obtain The Primary Key Definition Of A Table
9582**
9583** For each modified table, a changeset includes the following:
9584**
9585** <ul>
9586** <li> The number of columns in the table, and
9587** <li> Which of those columns make up the tables PRIMARY KEY.
9588** </ul>
9589**
9590** This function is used to find which columns comprise the PRIMARY KEY of
9591** the table modified by the change that iterator pIter currently points to.
9592** If successful, *pabPK is set to point to an array of nCol entries, where
9593** nCol is the number of columns in the table. Elements of *pabPK are set to
9594** 0x01 if the corresponding column is part of the tables primary key, or
9595** 0x00 if it is not.
9596**
9597** If argument pnCol is not NULL, then *pnCol is set to the number of columns
9598** in the table.
9599**
9600** If this function is called when the iterator does not point to a valid
9601** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
9602** SQLITE_OK is returned and the output variables populated as described
9603** above.
9604*/
9605SQLITE_API int sqlite3changeset_pk(
9606 sqlite3_changeset_iter *pIter, /* Iterator object */
9607 unsigned char **pabPK, /* OUT: Array of boolean - true for PK cols */
9608 int *pnCol /* OUT: Number of entries in output array */
9609);
9610
9611/*
9612** CAPI3REF: Obtain old.* Values From A Changeset Iterator
9613**
9614** The pIter argument passed to this function may either be an iterator
9615** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
9616** created by [sqlite3changeset_start()]. In the latter case, the most recent
9617** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
9618** Furthermore, it may only be called if the type of change that the iterator
9619** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
9620** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
9621**
9622** Argument iVal must be greater than or equal to 0, and less than the number
9623** of columns in the table affected by the current change. Otherwise,
9624** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
9625**
9626** If successful, this function sets *ppValue to point to a protected
9627** sqlite3_value object containing the iVal'th value from the vector of
9628** original row values stored as part of the UPDATE or DELETE change and
9629** returns SQLITE_OK. The name of the function comes from the fact that this
9630** is similar to the "old.*" columns available to update or delete triggers.
9631**
9632** If some other error occurs (e.g. an OOM condition), an SQLite error code
9633** is returned and *ppValue is set to NULL.
9634*/
9635SQLITE_API int sqlite3changeset_old(
9636 sqlite3_changeset_iter *pIter, /* Changeset iterator */
9637 int iVal, /* Column number */
9638 sqlite3_value **ppValue /* OUT: Old value (or NULL pointer) */
9639);
9640
9641/*
9642** CAPI3REF: Obtain new.* Values From A Changeset Iterator
9643**
9644** The pIter argument passed to this function may either be an iterator
9645** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
9646** created by [sqlite3changeset_start()]. In the latter case, the most recent
9647** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
9648** Furthermore, it may only be called if the type of change that the iterator
9649** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
9650** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
9651**
9652** Argument iVal must be greater than or equal to 0, and less than the number
9653** of columns in the table affected by the current change. Otherwise,
9654** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
9655**
9656** If successful, this function sets *ppValue to point to a protected
9657** sqlite3_value object containing the iVal'th value from the vector of
9658** new row values stored as part of the UPDATE or INSERT change and
9659** returns SQLITE_OK. If the change is an UPDATE and does not include
9660** a new value for the requested column, *ppValue is set to NULL and
9661** SQLITE_OK returned. The name of the function comes from the fact that
9662** this is similar to the "new.*" columns available to update or delete
9663** triggers.
9664**
9665** If some other error occurs (e.g. an OOM condition), an SQLite error code
9666** is returned and *ppValue is set to NULL.
9667*/
9668SQLITE_API int sqlite3changeset_new(
9669 sqlite3_changeset_iter *pIter, /* Changeset iterator */
9670 int iVal, /* Column number */
9671 sqlite3_value **ppValue /* OUT: New value (or NULL pointer) */
9672);
9673
9674/*
9675** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
9676**
9677** This function should only be used with iterator objects passed to a
9678** conflict-handler callback by [sqlite3changeset_apply()] with either
9679** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
9680** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
9681** is set to NULL.
9682**
9683** Argument iVal must be greater than or equal to 0, and less than the number
9684** of columns in the table affected by the current change. Otherwise,
9685** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
9686**
9687** If successful, this function sets *ppValue to point to a protected
9688** sqlite3_value object containing the iVal'th value from the
9689** "conflicting row" associated with the current conflict-handler callback
9690** and returns SQLITE_OK.
9691**
9692** If some other error occurs (e.g. an OOM condition), an SQLite error code
9693** is returned and *ppValue is set to NULL.
9694*/
9695SQLITE_API int sqlite3changeset_conflict(
9696 sqlite3_changeset_iter *pIter, /* Changeset iterator */
9697 int iVal, /* Column number */
9698 sqlite3_value **ppValue /* OUT: Value from conflicting row */
9699);
9700
9701/*
9702** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
9703**
9704** This function may only be called with an iterator passed to an
9705** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
9706** it sets the output variable to the total number of known foreign key
9707** violations in the destination database and returns SQLITE_OK.
9708**
9709** In all other cases this function returns SQLITE_MISUSE.
9710*/
9711SQLITE_API int sqlite3changeset_fk_conflicts(
9712 sqlite3_changeset_iter *pIter, /* Changeset iterator */
9713 int *pnOut /* OUT: Number of FK violations */
9714);
9715
9716
9717/*
9718** CAPI3REF: Finalize A Changeset Iterator
9719**
9720** This function is used to finalize an iterator allocated with
9721** [sqlite3changeset_start()].
9722**
9723** This function should only be called on iterators created using the
9724** [sqlite3changeset_start()] function. If an application calls this
9725** function with an iterator passed to a conflict-handler by
9726** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
9727** call has no effect.
9728**
9729** If an error was encountered within a call to an sqlite3changeset_xxx()
9730** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an
9731** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
9732** to that error is returned by this function. Otherwise, SQLITE_OK is
9733** returned. This is to allow the following pattern (pseudo-code):
9734**
9735** sqlite3changeset_start();
9736** while( SQLITE_ROW==sqlite3changeset_next() ){
9737** // Do something with change.
9738** }
9739** rc = sqlite3changeset_finalize();
9740** if( rc!=SQLITE_OK ){
9741** // An error has occurred
9742** }
9743*/
9744SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);
9745
9746/*
9747** CAPI3REF: Invert A Changeset
9748**
9749** This function is used to "invert" a changeset object. Applying an inverted
9750** changeset to a database reverses the effects of applying the uninverted
9751** changeset. Specifically:
9752**
9753** <ul>
9754** <li> Each DELETE change is changed to an INSERT, and
9755** <li> Each INSERT change is changed to a DELETE, and
9756** <li> For each UPDATE change, the old.* and new.* values are exchanged.
9757** </ul>
9758**
9759** This function does not change the order in which changes appear within
9760** the changeset. It merely reverses the sense of each individual change.
9761**
9762** If successful, a pointer to a buffer containing the inverted changeset
9763** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
9764** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
9765** zeroed and an SQLite error code returned.
9766**
9767** It is the responsibility of the caller to eventually call sqlite3_free()
9768** on the *ppOut pointer to free the buffer allocation following a successful
9769** call to this function.
9770**
9771** WARNING/TODO: This function currently assumes that the input is a valid
9772** changeset. If it is not, the results are undefined.
9773*/
9774SQLITE_API int sqlite3changeset_invert(
9775 int nIn, const void *pIn, /* Input changeset */
9776 int *pnOut, void **ppOut /* OUT: Inverse of input */
9777);
9778
9779/*
9780** CAPI3REF: Concatenate Two Changeset Objects
9781**
9782** This function is used to concatenate two changesets, A and B, into a
9783** single changeset. The result is a changeset equivalent to applying
9784** changeset A followed by changeset B.
9785**
9786** This function combines the two input changesets using an
9787** sqlite3_changegroup object. Calling it produces similar results as the
9788** following code fragment:
9789**
9790** sqlite3_changegroup *pGrp;
9791** rc = sqlite3_changegroup_new(&pGrp);
9792** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
9793** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
9794** if( rc==SQLITE_OK ){
9795** rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
9796** }else{
9797** *ppOut = 0;
9798** *pnOut = 0;
9799** }
9800**
9801** Refer to the sqlite3_changegroup documentation below for details.
9802*/
9803SQLITE_API int sqlite3changeset_concat(
9804 int nA, /* Number of bytes in buffer pA */
9805 void *pA, /* Pointer to buffer containing changeset A */
9806 int nB, /* Number of bytes in buffer pB */
9807 void *pB, /* Pointer to buffer containing changeset B */
9808 int *pnOut, /* OUT: Number of bytes in output changeset */
9809 void **ppOut /* OUT: Buffer containing output changeset */
9810);
9811
9812
9813/*
9814** CAPI3REF: Changegroup Handle
9815*/
9816typedef struct sqlite3_changegroup sqlite3_changegroup;
9817
9818/*
9819** CAPI3REF: Create A New Changegroup Object
9820**
9821** An sqlite3_changegroup object is used to combine two or more changesets
9822** (or patchsets) into a single changeset (or patchset). A single changegroup
9823** object may combine changesets or patchsets, but not both. The output is
9824** always in the same format as the input.
9825**
9826** If successful, this function returns SQLITE_OK and populates (*pp) with
9827** a pointer to a new sqlite3_changegroup object before returning. The caller
9828** should eventually free the returned object using a call to
9829** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
9830** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
9831**
9832** The usual usage pattern for an sqlite3_changegroup object is as follows:
9833**
9834** <ul>
9835** <li> It is created using a call to sqlite3changegroup_new().
9836**
9837** <li> Zero or more changesets (or patchsets) are added to the object
9838** by calling sqlite3changegroup_add().
9839**
9840** <li> The result of combining all input changesets together is obtained
9841** by the application via a call to sqlite3changegroup_output().
9842**
9843** <li> The object is deleted using a call to sqlite3changegroup_delete().
9844** </ul>
9845**
9846** Any number of calls to add() and output() may be made between the calls to
9847** new() and delete(), and in any order.
9848**
9849** As well as the regular sqlite3changegroup_add() and
9850** sqlite3changegroup_output() functions, also available are the streaming
9851** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
9852*/
9853SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp);
9854
9855/*
9856** CAPI3REF: Add A Changeset To A Changegroup
9857**
9858** Add all changes within the changeset (or patchset) in buffer pData (size
9859** nData bytes) to the changegroup.
9860**
9861** If the buffer contains a patchset, then all prior calls to this function
9862** on the same changegroup object must also have specified patchsets. Or, if
9863** the buffer contains a changeset, so must have the earlier calls to this
9864** function. Otherwise, SQLITE_ERROR is returned and no changes are added
9865** to the changegroup.
9866**
9867** Rows within the changeset and changegroup are identified by the values in
9868** their PRIMARY KEY columns. A change in the changeset is considered to
9869** apply to the same row as a change already present in the changegroup if
9870** the two rows have the same primary key.
9871**
9872** Changes to rows that do not already appear in the changegroup are
9873** simply copied into it. Or, if both the new changeset and the changegroup
9874** contain changes that apply to a single row, the final contents of the
9875** changegroup depends on the type of each change, as follows:
9876**
9877** <table border=1 style="margin-left:8ex;margin-right:8ex">
9878** <tr><th style="white-space:pre">Existing Change </th>
9879** <th style="white-space:pre">New Change </th>
9880** <th>Output Change
9881** <tr><td>INSERT <td>INSERT <td>
9882** The new change is ignored. This case does not occur if the new
9883** changeset was recorded immediately after the changesets already
9884** added to the changegroup.
9885** <tr><td>INSERT <td>UPDATE <td>
9886** The INSERT change remains in the changegroup. The values in the
9887** INSERT change are modified as if the row was inserted by the
9888** existing change and then updated according to the new change.
9889** <tr><td>INSERT <td>DELETE <td>
9890** The existing INSERT is removed from the changegroup. The DELETE is
9891** not added.
9892** <tr><td>UPDATE <td>INSERT <td>
9893** The new change is ignored. This case does not occur if the new
9894** changeset was recorded immediately after the changesets already
9895** added to the changegroup.
9896** <tr><td>UPDATE <td>UPDATE <td>
9897** The existing UPDATE remains within the changegroup. It is amended
9898** so that the accompanying values are as if the row was updated once
9899** by the existing change and then again by the new change.
9900** <tr><td>UPDATE <td>DELETE <td>
9901** The existing UPDATE is replaced by the new DELETE within the
9902** changegroup.
9903** <tr><td>DELETE <td>INSERT <td>
9904** If one or more of the column values in the row inserted by the
9905** new change differ from those in the row deleted by the existing
9906** change, the existing DELETE is replaced by an UPDATE within the
9907** changegroup. Otherwise, if the inserted row is exactly the same
9908** as the deleted row, the existing DELETE is simply discarded.
9909** <tr><td>DELETE <td>UPDATE <td>
9910** The new change is ignored. This case does not occur if the new
9911** changeset was recorded immediately after the changesets already
9912** added to the changegroup.
9913** <tr><td>DELETE <td>DELETE <td>
9914** The new change is ignored. This case does not occur if the new
9915** changeset was recorded immediately after the changesets already
9916** added to the changegroup.
9917** </table>
9918**
9919** If the new changeset contains changes to a table that is already present
9920** in the changegroup, then the number of columns and the position of the
9921** primary key columns for the table must be consistent. If this is not the
9922** case, this function fails with SQLITE_SCHEMA. If the input changeset
9923** appears to be corrupt and the corruption is detected, SQLITE_CORRUPT is
9924** returned. Or, if an out-of-memory condition occurs during processing, this
9925** function returns SQLITE_NOMEM. In all cases, if an error occurs the
9926** final contents of the changegroup is undefined.
9927**
9928** If no error occurs, SQLITE_OK is returned.
9929*/
9930SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData);
9931
9932/*
9933** CAPI3REF: Obtain A Composite Changeset From A Changegroup
9934**
9935** Obtain a buffer containing a changeset (or patchset) representing the
9936** current contents of the changegroup. If the inputs to the changegroup
9937** were themselves changesets, the output is a changeset. Or, if the
9938** inputs were patchsets, the output is also a patchset.
9939**
9940** As with the output of the sqlite3session_changeset() and
9941** sqlite3session_patchset() functions, all changes related to a single
9942** table are grouped together in the output of this function. Tables appear
9943** in the same order as for the very first changeset added to the changegroup.
9944** If the second or subsequent changesets added to the changegroup contain
9945** changes for tables that do not appear in the first changeset, they are
9946** appended onto the end of the output changeset, again in the order in
9947** which they are first encountered.
9948**
9949** If an error occurs, an SQLite error code is returned and the output
9950** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
9951** is returned and the output variables are set to the size of and a
9952** pointer to the output buffer, respectively. In this case it is the
9953** responsibility of the caller to eventually free the buffer using a
9954** call to sqlite3_free().
9955*/
9956SQLITE_API int sqlite3changegroup_output(
9957 sqlite3_changegroup*,
9958 int *pnData, /* OUT: Size of output buffer in bytes */
9959 void **ppData /* OUT: Pointer to output buffer */
9960);
9961
9962/*
9963** CAPI3REF: Delete A Changegroup Object
9964*/
9965SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup*);
9966
9967/*
9968** CAPI3REF: Apply A Changeset To A Database
9969**
9970** Apply a changeset to a database. This function attempts to update the
9971** "main" database attached to handle db with the changes found in the
9972** changeset passed via the second and third arguments.
9973**
9974** The fourth argument (xFilter) passed to this function is the "filter
9975** callback". If it is not NULL, then for each table affected by at least one
9976** change in the changeset, the filter callback is invoked with
9977** the table name as the second argument, and a copy of the context pointer
9978** passed as the sixth argument to this function as the first. If the "filter
9979** callback" returns zero, then no attempt is made to apply any changes to
9980** the table. Otherwise, if the return value is non-zero or the xFilter
9981** argument to this function is NULL, all changes related to the table are
9982** attempted.
9983**
9984** For each table that is not excluded by the filter callback, this function
9985** tests that the target database contains a compatible table. A table is
9986** considered compatible if all of the following are true:
9987**
9988** <ul>
9989** <li> The table has the same name as the name recorded in the
9990** changeset, and
9991** <li> The table has at least as many columns as recorded in the
9992** changeset, and
9993** <li> The table has primary key columns in the same position as
9994** recorded in the changeset.
9995** </ul>
9996**
9997** If there is no compatible table, it is not an error, but none of the
9998** changes associated with the table are applied. A warning message is issued
9999** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
10000** one such warning is issued for each table in the changeset.
10001**
10002** For each change for which there is a compatible table, an attempt is made
10003** to modify the table contents according to the UPDATE, INSERT or DELETE
10004** change. If a change cannot be applied cleanly, the conflict handler
10005** function passed as the fifth argument to sqlite3changeset_apply() may be
10006** invoked. A description of exactly when the conflict handler is invoked for
10007** each type of change is below.
10008**
10009** Unlike the xFilter argument, xConflict may not be passed NULL. The results
10010** of passing anything other than a valid function pointer as the xConflict
10011** argument are undefined.
10012**
10013** Each time the conflict handler function is invoked, it must return one
10014** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or
10015** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
10016** if the second argument passed to the conflict handler is either
10017** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
10018** returns an illegal value, any changes already made are rolled back and
10019** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different
10020** actions are taken by sqlite3changeset_apply() depending on the value
10021** returned by each invocation of the conflict-handler function. Refer to
10022** the documentation for the three
10023** [SQLITE_CHANGESET_OMIT|available return values] for details.
10024**
10025** <dl>
10026** <dt>DELETE Changes<dd>
10027** For each DELETE change, this function checks if the target database
10028** contains a row with the same primary key value (or values) as the
10029** original row values stored in the changeset. If it does, and the values
10030** stored in all non-primary key columns also match the values stored in
10031** the changeset the row is deleted from the target database.
10032**
10033** If a row with matching primary key values is found, but one or more of
10034** the non-primary key fields contains a value different from the original
10035** row value stored in the changeset, the conflict-handler function is
10036** invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the
10037** database table has more columns than are recorded in the changeset,
10038** only the values of those non-primary key fields are compared against
10039** the current database contents - any trailing database table columns
10040** are ignored.
10041**
10042** If no row with matching primary key values is found in the database,
10043** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
10044** passed as the second argument.
10045**
10046** If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
10047** (which can only happen if a foreign key constraint is violated), the
10048** conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
10049** passed as the second argument. This includes the case where the DELETE
10050** operation is attempted because an earlier call to the conflict handler
10051** function returned [SQLITE_CHANGESET_REPLACE].
10052**
10053** <dt>INSERT Changes<dd>
10054** For each INSERT change, an attempt is made to insert the new row into
10055** the database. If the changeset row contains fewer fields than the
10056** database table, the trailing fields are populated with their default
10057** values.
10058**
10059** If the attempt to insert the row fails because the database already
10060** contains a row with the same primary key values, the conflict handler
10061** function is invoked with the second argument set to
10062** [SQLITE_CHANGESET_CONFLICT].
10063**
10064** If the attempt to insert the row fails because of some other constraint
10065** violation (e.g. NOT NULL or UNIQUE), the conflict handler function is
10066** invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
10067** This includes the case where the INSERT operation is re-attempted because
10068** an earlier call to the conflict handler function returned
10069** [SQLITE_CHANGESET_REPLACE].
10070**
10071** <dt>UPDATE Changes<dd>
10072** For each UPDATE change, this function checks if the target database
10073** contains a row with the same primary key value (or values) as the
10074** original row values stored in the changeset. If it does, and the values
10075** stored in all modified non-primary key columns also match the values
10076** stored in the changeset the row is updated within the target database.
10077**
10078** If a row with matching primary key values is found, but one or more of
10079** the modified non-primary key fields contains a value different from an
10080** original row value stored in the changeset, the conflict-handler function
10081** is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
10082** UPDATE changes only contain values for non-primary key fields that are
10083** to be modified, only those fields need to match the original values to
10084** avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
10085**
10086** If no row with matching primary key values is found in the database,
10087** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
10088** passed as the second argument.
10089**
10090** If the UPDATE operation is attempted, but SQLite returns
10091** SQLITE_CONSTRAINT, the conflict-handler function is invoked with
10092** [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
10093** This includes the case where the UPDATE operation is attempted after
10094** an earlier call to the conflict handler function returned
10095** [SQLITE_CHANGESET_REPLACE].
10096** </dl>
10097**
10098** It is safe to execute SQL statements, including those that write to the
10099** table that the callback related to, from within the xConflict callback.
10100** This can be used to further customize the applications conflict
10101** resolution strategy.
10102**
10103** All changes made by this function are enclosed in a savepoint transaction.
10104** If any other error (aside from a constraint failure when attempting to
10105** write to the target database) occurs, then the savepoint transaction is
10106** rolled back, restoring the target database to its original state, and an
10107** SQLite error code returned.
10108*/
10109SQLITE_API int sqlite3changeset_apply(
10110 sqlite3 *db, /* Apply change to "main" db of this handle */
10111 int nChangeset, /* Size of changeset in bytes */
10112 void *pChangeset, /* Changeset blob */
10113 int(*xFilter)(
10114 void *pCtx, /* Copy of sixth arg to _apply() */
10115 const char *zTab /* Table name */
10116 ),
10117 int(*xConflict)(
10118 void *pCtx, /* Copy of sixth arg to _apply() */
10119 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */
10120 sqlite3_changeset_iter *p /* Handle describing change and conflict */
10121 ),
10122 void *pCtx /* First argument passed to xConflict */
10123);
10124
10125/*
10126** CAPI3REF: Constants Passed To The Conflict Handler
10127**
10128** Values that may be passed as the second argument to a conflict-handler.
10129**
10130** <dl>
10131** <dt>SQLITE_CHANGESET_DATA<dd>
10132** The conflict handler is invoked with CHANGESET_DATA as the second argument
10133** when processing a DELETE or UPDATE change if a row with the required
10134** PRIMARY KEY fields is present in the database, but one or more other
10135** (non primary-key) fields modified by the update do not contain the
10136** expected "before" values.
10137**
10138** The conflicting row, in this case, is the database row with the matching
10139** primary key.
10140**
10141** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
10142** The conflict handler is invoked with CHANGESET_NOTFOUND as the second
10143** argument when processing a DELETE or UPDATE change if a row with the
10144** required PRIMARY KEY fields is not present in the database.
10145**
10146** There is no conflicting row in this case. The results of invoking the
10147** sqlite3changeset_conflict() API are undefined.
10148**
10149** <dt>SQLITE_CHANGESET_CONFLICT<dd>
10150** CHANGESET_CONFLICT is passed as the second argument to the conflict
10151** handler while processing an INSERT change if the operation would result
10152** in duplicate primary key values.
10153**
10154** The conflicting row in this case is the database row with the matching
10155** primary key.
10156**
10157** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
10158** If foreign key handling is enabled, and applying a changeset leaves the
10159** database in a state containing foreign key violations, the conflict
10160** handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
10161** exactly once before the changeset is committed. If the conflict handler
10162** returns CHANGESET_OMIT, the changes, including those that caused the
10163** foreign key constraint violation, are committed. Or, if it returns
10164** CHANGESET_ABORT, the changeset is rolled back.
10165**
10166** No current or conflicting row information is provided. The only function
10167** it is possible to call on the supplied sqlite3_changeset_iter handle
10168** is sqlite3changeset_fk_conflicts().
10169**
10170** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
10171** If any other constraint violation occurs while applying a change (i.e.
10172** a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is
10173** invoked with CHANGESET_CONSTRAINT as the second argument.
10174**
10175** There is no conflicting row in this case. The results of invoking the
10176** sqlite3changeset_conflict() API are undefined.
10177**
10178** </dl>
10179*/
10180#define SQLITE_CHANGESET_DATA 1
10181#define SQLITE_CHANGESET_NOTFOUND 2
10182#define SQLITE_CHANGESET_CONFLICT 3
10183#define SQLITE_CHANGESET_CONSTRAINT 4
10184#define SQLITE_CHANGESET_FOREIGN_KEY 5
10185
10186/*
10187** CAPI3REF: Constants Returned By The Conflict Handler
10188**
10189** A conflict handler callback must return one of the following three values.
10190**
10191** <dl>
10192** <dt>SQLITE_CHANGESET_OMIT<dd>
10193** If a conflict handler returns this value no special action is taken. The
10194** change that caused the conflict is not applied. The session module
10195** continues to the next change in the changeset.
10196**
10197** <dt>SQLITE_CHANGESET_REPLACE<dd>
10198** This value may only be returned if the second argument to the conflict
10199** handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
10200** is not the case, any changes applied so far are rolled back and the
10201** call to sqlite3changeset_apply() returns SQLITE_MISUSE.
10202**
10203** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
10204** handler, then the conflicting row is either updated or deleted, depending
10205** on the type of change.
10206**
10207** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
10208** handler, then the conflicting row is removed from the database and a
10209** second attempt to apply the change is made. If this second attempt fails,
10210** the original row is restored to the database before continuing.
10211**
10212** <dt>SQLITE_CHANGESET_ABORT<dd>
10213** If this value is returned, any changes applied so far are rolled back
10214** and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
10215** </dl>
10216*/
10217#define SQLITE_CHANGESET_OMIT 0
10218#define SQLITE_CHANGESET_REPLACE 1
10219#define SQLITE_CHANGESET_ABORT 2
10220
10221/*
10222** CAPI3REF: Streaming Versions of API functions.
10223**
10224** The six streaming API xxx_strm() functions serve similar purposes to the
10225** corresponding non-streaming API functions:
10226**
10227** <table border=1 style="margin-left:8ex;margin-right:8ex">
10228** <tr><th>Streaming function<th>Non-streaming equivalent</th>
10229** <tr><td>sqlite3changeset_apply_strm<td>[sqlite3changeset_apply]
10230** <tr><td>sqlite3changeset_concat_strm<td>[sqlite3changeset_concat]
10231** <tr><td>sqlite3changeset_invert_strm<td>[sqlite3changeset_invert]
10232** <tr><td>sqlite3changeset_start_strm<td>[sqlite3changeset_start]
10233** <tr><td>sqlite3session_changeset_strm<td>[sqlite3session_changeset]
10234** <tr><td>sqlite3session_patchset_strm<td>[sqlite3session_patchset]
10235** </table>
10236**
10237** Non-streaming functions that accept changesets (or patchsets) as input
10238** require that the entire changeset be stored in a single buffer in memory.
10239** Similarly, those that return a changeset or patchset do so by returning
10240** a pointer to a single large buffer allocated using sqlite3_malloc().
10241** Normally this is convenient. However, if an application running in a
10242** low-memory environment is required to handle very large changesets, the
10243** large contiguous memory allocations required can become onerous.
10244**
10245** In order to avoid this problem, instead of a single large buffer, input
10246** is passed to a streaming API functions by way of a callback function that
10247** the sessions module invokes to incrementally request input data as it is
10248** required. In all cases, a pair of API function parameters such as
10249**
10250** <pre>
10251** &nbsp; int nChangeset,
10252** &nbsp; void *pChangeset,
10253** </pre>
10254**
10255** Is replaced by:
10256**
10257** <pre>
10258** &nbsp; int (*xInput)(void *pIn, void *pData, int *pnData),
10259** &nbsp; void *pIn,
10260** </pre>
10261**
10262** Each time the xInput callback is invoked by the sessions module, the first
10263** argument passed is a copy of the supplied pIn context pointer. The second
10264** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no
10265** error occurs the xInput method should copy up to (*pnData) bytes of data
10266** into the buffer and set (*pnData) to the actual number of bytes copied
10267** before returning SQLITE_OK. If the input is completely exhausted, (*pnData)
10268** should be set to zero to indicate this. Or, if an error occurs, an SQLite
10269** error code should be returned. In all cases, if an xInput callback returns
10270** an error, all processing is abandoned and the streaming API function
10271** returns a copy of the error code to the caller.
10272**
10273** In the case of sqlite3changeset_start_strm(), the xInput callback may be
10274** invoked by the sessions module at any point during the lifetime of the
10275** iterator. If such an xInput callback returns an error, the iterator enters
10276** an error state, whereby all subsequent calls to iterator functions
10277** immediately fail with the same error code as returned by xInput.
10278**
10279** Similarly, streaming API functions that return changesets (or patchsets)
10280** return them in chunks by way of a callback function instead of via a
10281** pointer to a single large buffer. In this case, a pair of parameters such
10282** as:
10283**
10284** <pre>
10285** &nbsp; int *pnChangeset,
10286** &nbsp; void **ppChangeset,
10287** </pre>
10288**
10289** Is replaced by:
10290**
10291** <pre>
10292** &nbsp; int (*xOutput)(void *pOut, const void *pData, int nData),
10293** &nbsp; void *pOut
10294** </pre>
10295**
10296** The xOutput callback is invoked zero or more times to return data to
10297** the application. The first parameter passed to each call is a copy of the
10298** pOut pointer supplied by the application. The second parameter, pData,
10299** points to a buffer nData bytes in size containing the chunk of output
10300** data being returned. If the xOutput callback successfully processes the
10301** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
10302** it should return some other SQLite error code. In this case processing
10303** is immediately abandoned and the streaming API function returns a copy
10304** of the xOutput error code to the application.
10305**
10306** The sessions module never invokes an xOutput callback with the third
10307** parameter set to a value less than or equal to zero. Other than this,
10308** no guarantees are made as to the size of the chunks of data returned.
10309*/
10310SQLITE_API int sqlite3changeset_apply_strm(
10311 sqlite3 *db, /* Apply change to "main" db of this handle */
10312 int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
10313 void *pIn, /* First arg for xInput */
10314 int(*xFilter)(
10315 void *pCtx, /* Copy of sixth arg to _apply() */
10316 const char *zTab /* Table name */
10317 ),
10318 int(*xConflict)(
10319 void *pCtx, /* Copy of sixth arg to _apply() */
10320 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */
10321 sqlite3_changeset_iter *p /* Handle describing change and conflict */
10322 ),
10323 void *pCtx /* First argument passed to xConflict */
10324);
10325SQLITE_API int sqlite3changeset_concat_strm(
10326 int (*xInputA)(void *pIn, void *pData, int *pnData),
10327 void *pInA,
10328 int (*xInputB)(void *pIn, void *pData, int *pnData),
10329 void *pInB,
10330 int (*xOutput)(void *pOut, const void *pData, int nData),
10331 void *pOut
10332);
10333SQLITE_API int sqlite3changeset_invert_strm(
10334 int (*xInput)(void *pIn, void *pData, int *pnData),
10335 void *pIn,
10336 int (*xOutput)(void *pOut, const void *pData, int nData),
10337 void *pOut
10338);
10339SQLITE_API int sqlite3changeset_start_strm(
10340 sqlite3_changeset_iter **pp,
10341 int (*xInput)(void *pIn, void *pData, int *pnData),
10342 void *pIn
10343);
10344SQLITE_API int sqlite3session_changeset_strm(
10345 sqlite3_session *pSession,
10346 int (*xOutput)(void *pOut, const void *pData, int nData),
10347 void *pOut
10348);
10349SQLITE_API int sqlite3session_patchset_strm(
10350 sqlite3_session *pSession,
10351 int (*xOutput)(void *pOut, const void *pData, int nData),
10352 void *pOut
10353);
10354SQLITE_API int sqlite3changegroup_add_strm(sqlite3_changegroup*,
10355 int (*xInput)(void *pIn, void *pData, int *pnData),
10356 void *pIn
10357);
10358SQLITE_API int sqlite3changegroup_output_strm(sqlite3_changegroup*,
10359 int (*xOutput)(void *pOut, const void *pData, int nData),
10360 void *pOut
10361);
10362
10363
10364/*
10365** Make sure we can call this stuff from C++.
10366*/
10367#ifdef __cplusplus
10368}
10369#endif
10370
10371#endif /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
10372
10373/******** End of sqlite3session.h *********/
10374/******** Begin file fts5.h *********/
10375/*
10376** 2014 May 31
10377**
10378** The author disclaims copyright to this source code. In place of
10379** a legal notice, here is a blessing:
10380**
10381** May you do good and not evil.
10382** May you find forgiveness for yourself and forgive others.
10383** May you share freely, never taking more than you give.
10384**
10385******************************************************************************
10386**
10387** Interfaces to extend FTS5. Using the interfaces defined in this file,
10388** FTS5 may be extended with:
10389**
10390** * custom tokenizers, and
10391** * custom auxiliary functions.
10392*/
10393
10394
10395#ifndef _FTS5_H
10396#define _FTS5_H
10397
10398
10399#ifdef __cplusplus
10400extern "C" {
10401#endif
10402
10403/*************************************************************************
10404** CUSTOM AUXILIARY FUNCTIONS
10405**
10406** Virtual table implementations may overload SQL functions by implementing
10407** the sqlite3_module.xFindFunction() method.
10408*/
10409
10410typedef struct Fts5ExtensionApi Fts5ExtensionApi;
10411typedef struct Fts5Context Fts5Context;
10412typedef struct Fts5PhraseIter Fts5PhraseIter;
10413
10414typedef void (*fts5_extension_function)(
10415 const Fts5ExtensionApi *pApi, /* API offered by current FTS version */
10416 Fts5Context *pFts, /* First arg to pass to pApi functions */
10417 sqlite3_context *pCtx, /* Context for returning result/error */
10418 int nVal, /* Number of values in apVal[] array */
10419 sqlite3_value **apVal /* Array of trailing arguments */
10420);
10421
10422struct Fts5PhraseIter {
10423 const unsigned char *a;
10424 const unsigned char *b;
10425};
10426
10427/*
10428** EXTENSION API FUNCTIONS
10429**
10430** xUserData(pFts):
10431** Return a copy of the context pointer the extension function was
10432** registered with.
10433**
10434** xColumnTotalSize(pFts, iCol, pnToken):
10435** If parameter iCol is less than zero, set output variable *pnToken
10436** to the total number of tokens in the FTS5 table. Or, if iCol is
10437** non-negative but less than the number of columns in the table, return
10438** the total number of tokens in column iCol, considering all rows in
10439** the FTS5 table.
10440**
10441** If parameter iCol is greater than or equal to the number of columns
10442** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
10443** an OOM condition or IO error), an appropriate SQLite error code is
10444** returned.
10445**
10446** xColumnCount(pFts):
10447** Return the number of columns in the table.
10448**
10449** xColumnSize(pFts, iCol, pnToken):
10450** If parameter iCol is less than zero, set output variable *pnToken
10451** to the total number of tokens in the current row. Or, if iCol is
10452** non-negative but less than the number of columns in the table, set
10453** *pnToken to the number of tokens in column iCol of the current row.
10454**
10455** If parameter iCol is greater than or equal to the number of columns
10456** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
10457** an OOM condition or IO error), an appropriate SQLite error code is
10458** returned.
10459**
10460** This function may be quite inefficient if used with an FTS5 table
10461** created with the "columnsize=0" option.
10462**
10463** xColumnText:
10464** This function attempts to retrieve the text of column iCol of the
10465** current document. If successful, (*pz) is set to point to a buffer
10466** containing the text in utf-8 encoding, (*pn) is set to the size in bytes
10467** (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
10468** if an error occurs, an SQLite error code is returned and the final values
10469** of (*pz) and (*pn) are undefined.
10470**
10471** xPhraseCount:
10472** Returns the number of phrases in the current query expression.
10473**
10474** xPhraseSize:
10475** Returns the number of tokens in phrase iPhrase of the query. Phrases
10476** are numbered starting from zero.
10477**
10478** xInstCount:
10479** Set *pnInst to the total number of occurrences of all phrases within
10480** the query within the current row. Return SQLITE_OK if successful, or
10481** an error code (i.e. SQLITE_NOMEM) if an error occurs.
10482**
10483** This API can be quite slow if used with an FTS5 table created with the
10484** "detail=none" or "detail=column" option. If the FTS5 table is created
10485** with either "detail=none" or "detail=column" and "content=" option
10486** (i.e. if it is a contentless table), then this API always returns 0.
10487**
10488** xInst:
10489** Query for the details of phrase match iIdx within the current row.
10490** Phrase matches are numbered starting from zero, so the iIdx argument
10491** should be greater than or equal to zero and smaller than the value
10492** output by xInstCount().
10493**
10494** Usually, output parameter *piPhrase is set to the phrase number, *piCol
10495** to the column in which it occurs and *piOff the token offset of the
10496** first token of the phrase. The exception is if the table was created
10497** with the offsets=0 option specified. In this case *piOff is always
10498** set to -1.
10499**
10500** Returns SQLITE_OK if successful, or an error code (i.e. SQLITE_NOMEM)
10501** if an error occurs.
10502**
10503** This API can be quite slow if used with an FTS5 table created with the
10504** "detail=none" or "detail=column" option.
10505**
10506** xRowid:
10507** Returns the rowid of the current row.
10508**
10509** xTokenize:
10510** Tokenize text using the tokenizer belonging to the FTS5 table.
10511**
10512** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
10513** This API function is used to query the FTS table for phrase iPhrase
10514** of the current query. Specifically, a query equivalent to:
10515**
10516** ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
10517**
10518** with $p set to a phrase equivalent to the phrase iPhrase of the
10519** current query is executed. Any column filter that applies to
10520** phrase iPhrase of the current query is included in $p. For each
10521** row visited, the callback function passed as the fourth argument
10522** is invoked. The context and API objects passed to the callback
10523** function may be used to access the properties of each matched row.
10524** Invoking Api.xUserData() returns a copy of the pointer passed as
10525** the third argument to pUserData.
10526**
10527** If the callback function returns any value other than SQLITE_OK, the
10528** query is abandoned and the xQueryPhrase function returns immediately.
10529** If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
10530** Otherwise, the error code is propagated upwards.
10531**
10532** If the query runs to completion without incident, SQLITE_OK is returned.
10533** Or, if some error occurs before the query completes or is aborted by
10534** the callback, an SQLite error code is returned.
10535**
10536**
10537** xSetAuxdata(pFts5, pAux, xDelete)
10538**
10539** Save the pointer passed as the second argument as the extension functions
10540** "auxiliary data". The pointer may then be retrieved by the current or any
10541** future invocation of the same fts5 extension function made as part of
10542** of the same MATCH query using the xGetAuxdata() API.
10543**
10544** Each extension function is allocated a single auxiliary data slot for
10545** each FTS query (MATCH expression). If the extension function is invoked
10546** more than once for a single FTS query, then all invocations share a
10547** single auxiliary data context.
10548**
10549** If there is already an auxiliary data pointer when this function is
10550** invoked, then it is replaced by the new pointer. If an xDelete callback
10551** was specified along with the original pointer, it is invoked at this
10552** point.
10553**
10554** The xDelete callback, if one is specified, is also invoked on the
10555** auxiliary data pointer after the FTS5 query has finished.
10556**
10557** If an error (e.g. an OOM condition) occurs within this function, an
10558** the auxiliary data is set to NULL and an error code returned. If the
10559** xDelete parameter was not NULL, it is invoked on the auxiliary data
10560** pointer before returning.
10561**
10562**
10563** xGetAuxdata(pFts5, bClear)
10564**
10565** Returns the current auxiliary data pointer for the fts5 extension
10566** function. See the xSetAuxdata() method for details.
10567**
10568** If the bClear argument is non-zero, then the auxiliary data is cleared
10569** (set to NULL) before this function returns. In this case the xDelete,
10570** if any, is not invoked.
10571**
10572**
10573** xRowCount(pFts5, pnRow)
10574**
10575** This function is used to retrieve the total number of rows in the table.
10576** In other words, the same value that would be returned by:
10577**
10578** SELECT count(*) FROM ftstable;
10579**
10580** xPhraseFirst()
10581** This function is used, along with type Fts5PhraseIter and the xPhraseNext
10582** method, to iterate through all instances of a single query phrase within
10583** the current row. This is the same information as is accessible via the
10584** xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
10585** to use, this API may be faster under some circumstances. To iterate
10586** through instances of phrase iPhrase, use the following code:
10587**
10588** Fts5PhraseIter iter;
10589** int iCol, iOff;
10590** for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
10591** iCol>=0;
10592** pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
10593** ){
10594** // An instance of phrase iPhrase at offset iOff of column iCol
10595** }
10596**
10597** The Fts5PhraseIter structure is defined above. Applications should not
10598** modify this structure directly - it should only be used as shown above
10599** with the xPhraseFirst() and xPhraseNext() API methods (and by
10600** xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
10601**
10602** This API can be quite slow if used with an FTS5 table created with the
10603** "detail=none" or "detail=column" option. If the FTS5 table is created
10604** with either "detail=none" or "detail=column" and "content=" option
10605** (i.e. if it is a contentless table), then this API always iterates
10606** through an empty set (all calls to xPhraseFirst() set iCol to -1).
10607**
10608** xPhraseNext()
10609** See xPhraseFirst above.
10610**
10611** xPhraseFirstColumn()
10612** This function and xPhraseNextColumn() are similar to the xPhraseFirst()
10613** and xPhraseNext() APIs described above. The difference is that instead
10614** of iterating through all instances of a phrase in the current row, these
10615** APIs are used to iterate through the set of columns in the current row
10616** that contain one or more instances of a specified phrase. For example:
10617**
10618** Fts5PhraseIter iter;
10619** int iCol;
10620** for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
10621** iCol>=0;
10622** pApi->xPhraseNextColumn(pFts, &iter, &iCol)
10623** ){
10624** // Column iCol contains at least one instance of phrase iPhrase
10625** }
10626**
10627** This API can be quite slow if used with an FTS5 table created with the
10628** "detail=none" option. If the FTS5 table is created with either
10629** "detail=none" "content=" option (i.e. if it is a contentless table),
10630** then this API always iterates through an empty set (all calls to
10631** xPhraseFirstColumn() set iCol to -1).
10632**
10633** The information accessed using this API and its companion
10634** xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
10635** (or xInst/xInstCount). The chief advantage of this API is that it is
10636** significantly more efficient than those alternatives when used with
10637** "detail=column" tables.
10638**
10639** xPhraseNextColumn()
10640** See xPhraseFirstColumn above.
10641*/
10642struct Fts5ExtensionApi {
10643 int iVersion; /* Currently always set to 3 */
10644
10645 void *(*xUserData)(Fts5Context*);
10646
10647 int (*xColumnCount)(Fts5Context*);
10648 int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
10649 int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
10650
10651 int (*xTokenize)(Fts5Context*,
10652 const char *pText, int nText, /* Text to tokenize */
10653 void *pCtx, /* Context passed to xToken() */
10654 int (*xToken)(void*, int, const char*, int, int, int) /* Callback */
10655 );
10656
10657 int (*xPhraseCount)(Fts5Context*);
10658 int (*xPhraseSize)(Fts5Context*, int iPhrase);
10659
10660 int (*xInstCount)(Fts5Context*, int *pnInst);
10661 int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
10662
10663 sqlite3_int64 (*xRowid)(Fts5Context*);
10664 int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
10665 int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
10666
10667 int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
10668 int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
10669 );
10670 int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
10671 void *(*xGetAuxdata)(Fts5Context*, int bClear);
10672
10673 int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
10674 void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
10675
10676 int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
10677 void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
10678};
10679
10680/*
10681** CUSTOM AUXILIARY FUNCTIONS
10682*************************************************************************/
10683
10684/*************************************************************************
10685** CUSTOM TOKENIZERS
10686**
10687** Applications may also register custom tokenizer types. A tokenizer
10688** is registered by providing fts5 with a populated instance of the
10689** following structure. All structure methods must be defined, setting
10690** any member of the fts5_tokenizer struct to NULL leads to undefined
10691** behaviour. The structure methods are expected to function as follows:
10692**
10693** xCreate:
10694** This function is used to allocate and initialize a tokenizer instance.
10695** A tokenizer instance is required to actually tokenize text.
10696**
10697** The first argument passed to this function is a copy of the (void*)
10698** pointer provided by the application when the fts5_tokenizer object
10699** was registered with FTS5 (the third argument to xCreateTokenizer()).
10700** The second and third arguments are an array of nul-terminated strings
10701** containing the tokenizer arguments, if any, specified following the
10702** tokenizer name as part of the CREATE VIRTUAL TABLE statement used
10703** to create the FTS5 table.
10704**
10705** The final argument is an output variable. If successful, (*ppOut)
10706** should be set to point to the new tokenizer handle and SQLITE_OK
10707** returned. If an error occurs, some value other than SQLITE_OK should
10708** be returned. In this case, fts5 assumes that the final value of *ppOut
10709** is undefined.
10710**
10711** xDelete:
10712** This function is invoked to delete a tokenizer handle previously
10713** allocated using xCreate(). Fts5 guarantees that this function will
10714** be invoked exactly once for each successful call to xCreate().
10715**
10716** xTokenize:
10717** This function is expected to tokenize the nText byte string indicated
10718** by argument pText. pText may or may not be nul-terminated. The first
10719** argument passed to this function is a pointer to an Fts5Tokenizer object
10720** returned by an earlier call to xCreate().
10721**
10722** The second argument indicates the reason that FTS5 is requesting
10723** tokenization of the supplied text. This is always one of the following
10724** four values:
10725**
10726** <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
10727** or removed from the FTS table. The tokenizer is being invoked to
10728** determine the set of tokens to add to (or delete from) the
10729** FTS index.
10730**
10731** <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
10732** against the FTS index. The tokenizer is being called to tokenize
10733** a bareword or quoted string specified as part of the query.
10734**
10735** <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
10736** FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
10737** followed by a "*" character, indicating that the last token
10738** returned by the tokenizer will be treated as a token prefix.
10739**
10740** <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
10741** satisfy an fts5_api.xTokenize() request made by an auxiliary
10742** function. Or an fts5_api.xColumnSize() request made by the same
10743** on a columnsize=0 database.
10744** </ul>
10745**
10746** For each token in the input string, the supplied callback xToken() must
10747** be invoked. The first argument to it should be a copy of the pointer
10748** passed as the second argument to xTokenize(). The third and fourth
10749** arguments are a pointer to a buffer containing the token text, and the
10750** size of the token in bytes. The 4th and 5th arguments are the byte offsets
10751** of the first byte of and first byte immediately following the text from
10752** which the token is derived within the input.
10753**
10754** The second argument passed to the xToken() callback ("tflags") should
10755** normally be set to 0. The exception is if the tokenizer supports
10756** synonyms. In this case see the discussion below for details.
10757**
10758** FTS5 assumes the xToken() callback is invoked for each token in the
10759** order that they occur within the input text.
10760**
10761** If an xToken() callback returns any value other than SQLITE_OK, then
10762** the tokenization should be abandoned and the xTokenize() method should
10763** immediately return a copy of the xToken() return value. Or, if the
10764** input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
10765** if an error occurs with the xTokenize() implementation itself, it
10766** may abandon the tokenization and return any error code other than
10767** SQLITE_OK or SQLITE_DONE.
10768**
10769** SYNONYM SUPPORT
10770**
10771** Custom tokenizers may also support synonyms. Consider a case in which a
10772** user wishes to query for a phrase such as "first place". Using the
10773** built-in tokenizers, the FTS5 query 'first + place' will match instances
10774** of "first place" within the document set, but not alternative forms
10775** such as "1st place". In some applications, it would be better to match
10776** all instances of "first place" or "1st place" regardless of which form
10777** the user specified in the MATCH query text.
10778**
10779** There are several ways to approach this in FTS5:
10780**
10781** <ol><li> By mapping all synonyms to a single token. In this case, the
10782** In the above example, this means that the tokenizer returns the
10783** same token for inputs "first" and "1st". Say that token is in
10784** fact "first", so that when the user inserts the document "I won
10785** 1st place" entries are added to the index for tokens "i", "won",
10786** "first" and "place". If the user then queries for '1st + place',
10787** the tokenizer substitutes "first" for "1st" and the query works
10788** as expected.
10789**
10790** <li> By adding multiple synonyms for a single term to the FTS index.
10791** In this case, when tokenizing query text, the tokenizer may
10792** provide multiple synonyms for a single term within the document.
10793** FTS5 then queries the index for each synonym individually. For
10794** example, faced with the query:
10795**
10796** <codeblock>
10797** ... MATCH 'first place'</codeblock>
10798**
10799** the tokenizer offers both "1st" and "first" as synonyms for the
10800** first token in the MATCH query and FTS5 effectively runs a query
10801** similar to:
10802**
10803** <codeblock>
10804** ... MATCH '(first OR 1st) place'</codeblock>
10805**
10806** except that, for the purposes of auxiliary functions, the query
10807** still appears to contain just two phrases - "(first OR 1st)"
10808** being treated as a single phrase.
10809**
10810** <li> By adding multiple synonyms for a single term to the FTS index.
10811** Using this method, when tokenizing document text, the tokenizer
10812** provides multiple synonyms for each token. So that when a
10813** document such as "I won first place" is tokenized, entries are
10814** added to the FTS index for "i", "won", "first", "1st" and
10815** "place".
10816**
10817** This way, even if the tokenizer does not provide synonyms
10818** when tokenizing query text (it should not - to do would be
10819** inefficient), it doesn't matter if the user queries for
10820** 'first + place' or '1st + place', as there are entires in the
10821** FTS index corresponding to both forms of the first token.
10822** </ol>
10823**
10824** Whether it is parsing document or query text, any call to xToken that
10825** specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
10826** is considered to supply a synonym for the previous token. For example,
10827** when parsing the document "I won first place", a tokenizer that supports
10828** synonyms would call xToken() 5 times, as follows:
10829**
10830** <codeblock>
10831** xToken(pCtx, 0, "i", 1, 0, 1);
10832** xToken(pCtx, 0, "won", 3, 2, 5);
10833** xToken(pCtx, 0, "first", 5, 6, 11);
10834** xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3, 6, 11);
10835** xToken(pCtx, 0, "place", 5, 12, 17);
10836**</codeblock>
10837**
10838** It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
10839** xToken() is called. Multiple synonyms may be specified for a single token
10840** by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
10841** There is no limit to the number of synonyms that may be provided for a
10842** single token.
10843**
10844** In many cases, method (1) above is the best approach. It does not add
10845** extra data to the FTS index or require FTS5 to query for multiple terms,
10846** so it is efficient in terms of disk space and query speed. However, it
10847** does not support prefix queries very well. If, as suggested above, the
10848** token "first" is subsituted for "1st" by the tokenizer, then the query:
10849**
10850** <codeblock>
10851** ... MATCH '1s*'</codeblock>
10852**
10853** will not match documents that contain the token "1st" (as the tokenizer
10854** will probably not map "1s" to any prefix of "first").
10855**
10856** For full prefix support, method (3) may be preferred. In this case,
10857** because the index contains entries for both "first" and "1st", prefix
10858** queries such as 'fi*' or '1s*' will match correctly. However, because
10859** extra entries are added to the FTS index, this method uses more space
10860** within the database.
10861**
10862** Method (2) offers a midpoint between (1) and (3). Using this method,
10863** a query such as '1s*' will match documents that contain the literal
10864** token "1st", but not "first" (assuming the tokenizer is not able to
10865** provide synonyms for prefixes). However, a non-prefix query like '1st'
10866** will match against "1st" and "first". This method does not require
10867** extra disk space, as no extra entries are added to the FTS index.
10868** On the other hand, it may require more CPU cycles to run MATCH queries,
10869** as separate queries of the FTS index are required for each synonym.
10870**
10871** When using methods (2) or (3), it is important that the tokenizer only
10872** provide synonyms when tokenizing document text (method (2)) or query
10873** text (method (3)), not both. Doing so will not cause any errors, but is
10874** inefficient.
10875*/
10876typedef struct Fts5Tokenizer Fts5Tokenizer;
10877typedef struct fts5_tokenizer fts5_tokenizer;
10878struct fts5_tokenizer {
10879 int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
10880 void (*xDelete)(Fts5Tokenizer*);
10881 int (*xTokenize)(Fts5Tokenizer*,
10882 void *pCtx,
10883 int flags, /* Mask of FTS5_TOKENIZE_* flags */
10884 const char *pText, int nText,
10885 int (*xToken)(
10886 void *pCtx, /* Copy of 2nd argument to xTokenize() */
10887 int tflags, /* Mask of FTS5_TOKEN_* flags */
10888 const char *pToken, /* Pointer to buffer containing token */
10889 int nToken, /* Size of token in bytes */
10890 int iStart, /* Byte offset of token within input text */
10891 int iEnd /* Byte offset of end of token within input text */
10892 )
10893 );
10894};
10895
10896/* Flags that may be passed as the third argument to xTokenize() */
10897#define FTS5_TOKENIZE_QUERY 0x0001
10898#define FTS5_TOKENIZE_PREFIX 0x0002
10899#define FTS5_TOKENIZE_DOCUMENT 0x0004
10900#define FTS5_TOKENIZE_AUX 0x0008
10901
10902/* Flags that may be passed by the tokenizer implementation back to FTS5
10903** as the third argument to the supplied xToken callback. */
10904#define FTS5_TOKEN_COLOCATED 0x0001 /* Same position as prev. token */
10905
10906/*
10907** END OF CUSTOM TOKENIZERS
10908*************************************************************************/
10909
10910/*************************************************************************
10911** FTS5 EXTENSION REGISTRATION API
10912*/
10913typedef struct fts5_api fts5_api;
10914struct fts5_api {
10915 int iVersion; /* Currently always set to 2 */
10916
10917 /* Create a new tokenizer */
10918 int (*xCreateTokenizer)(
10919 fts5_api *pApi,
10920 const char *zName,
10921 void *pContext,
10922 fts5_tokenizer *pTokenizer,
10923 void (*xDestroy)(void*)
10924 );
10925
10926 /* Find an existing tokenizer */
10927 int (*xFindTokenizer)(
10928 fts5_api *pApi,
10929 const char *zName,
10930 void **ppContext,
10931 fts5_tokenizer *pTokenizer
10932 );
10933
10934 /* Create a new auxiliary function */
10935 int (*xCreateFunction)(
10936 fts5_api *pApi,
10937 const char *zName,
10938 void *pContext,
10939 fts5_extension_function xFunction,
10940 void (*xDestroy)(void*)
10941 );
10942};
10943
10944/*
10945** END OF REGISTRATION API
10946*************************************************************************/
10947
10948#ifdef __cplusplus
10949} /* end of the 'extern "C"' block */
10950#endif
10951
10952#endif /* _FTS5_H */
10953
10954/******** End of fts5.h *********/
10955