2** This file is an amalgamation of many separate C source files from SQLite
3** version  By combining all the individual C code files into this
4** single large file, the entire code can be compiled as a single translation
5** unit.  This allows many compilers to do optimizations that would not be
6** possible if the files were compiled separately.  Performance improvements
7** of 5% or more are commonly seen when SQLite is compiled as a single
8** translation unit.
10** This file is all you need to compile SQLite.  To use SQLite in other
11** programs, you need this file and the "sqlite3.h" header file that defines
12** the programming interface to the SQLite library.  (If you do not have
13** the "sqlite3.h" header file at hand, you will find a copy embedded within
14** the text of this file.  Search for "Begin file sqlite3.h" to find the start
15** of the embedded sqlite3.h header file.) Additional code files may be needed
16** if you want a wrapper to interface SQLite with your choice of programming
17** language. The code for the "sqlite3" command-line shell is also in a
18** separate file. This file contains only code for the core SQLite library.
20#define SQLITE_CORE 1
23# define SQLITE_PRIVATE static
25#ifndef SQLITE_API
26# define SQLITE_API
28/************** Begin file sqliteInt.h ***************************************/
30** 2001 September 15
32** The author disclaims copyright to this source code.  In place of
33** a legal notice, here is a blessing:
35**    May you do good and not evil.
36**    May you find forgiveness for yourself and forgive others.
37**    May you share freely, never taking more than you give.
40** Internal interface definitions for SQLite.
43#ifndef _SQLITEINT_H_
44#define _SQLITEINT_H_
47** Include the header file used to customize the compiler options for MSVC.
48** This should be done first so that it can successfully prevent spurious
49** compiler warnings due to subsequent content in this file and other files
50** that are included by this file.
52/************** Include msvc.h in the middle of sqliteInt.h ******************/
53/************** Begin file msvc.h ********************************************/
55** 2015 January 12
57** The author disclaims copyright to this source code.  In place of
58** a legal notice, here is a blessing:
60**    May you do good and not evil.
61**    May you find forgiveness for yourself and forgive others.
62**    May you share freely, never taking more than you give.
66** This file contains code that is specific to MSVC.
68#ifndef _MSVC_H_
69#define _MSVC_H_
71#if defined(_MSC_VER)
72#pragma warning(disable : 4054)
73#pragma warning(disable : 4055)
74#pragma warning(disable : 4100)
75#pragma warning(disable : 4127)
76#pragma warning(disable : 4152)
77#pragma warning(disable : 4189)
78#pragma warning(disable : 4206)
79#pragma warning(disable : 4210)
80#pragma warning(disable : 4232)
81#pragma warning(disable : 4244)
82#pragma warning(disable : 4305)
83#pragma warning(disable : 4306)
84#pragma warning(disable : 4702)
85#pragma warning(disable : 4706)
86#endif /* defined(_MSC_VER) */
88#endif /* _MSVC_H_ */
90/************** End of msvc.h ************************************************/
91/************** Continuing where we left off in sqliteInt.h ******************/
94** These #defines should enable >2GB file support on POSIX if the
95** underlying operating system supports it.  If the OS lacks
96** large file support, or if the OS is windows, these should be no-ops.
98** Ticket #2739:  The _LARGEFILE_SOURCE macro must appear before any
99** system #includes.  Hence, this block of code must be the very first
100** code in all source files.
102** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch
103** on the compiler command line.  This is necessary if you are compiling
104** on a recent machine (ex: Red Hat 7.2) but you want your code to work
105** on an older machine (ex: Red Hat 6.0).  If you compile on Red Hat 7.2
106** without this option, LFS is enable.  But LFS does not exist in the kernel
107** in Red Hat 6.0, so the code won't work.  Hence, for maximum binary
108** portability you should omit LFS.
110** The previous paragraph was written in 2005.  (This paragraph is written
111** on 2008-11-28.) These days, all Linux kernels support large files, so
112** you should probably leave LFS enabled.  But some embedded platforms might
113** lack LFS in which case the SQLITE_DISABLE_LFS macro might still be useful.
115** Similar is true for Mac OS X.  LFS is only supported on Mac OS X 9 and later.
118# define _LARGE_FILE       1
119# ifndef _FILE_OFFSET_BITS
120#   define _FILE_OFFSET_BITS 64
121# endif
122# define _LARGEFILE_SOURCE 1
125/* Needed for various definitions... */
126#if defined(__GNUC__) && !defined(_GNU_SOURCE)
127# define _GNU_SOURCE
130#if defined(__OpenBSD__) && !defined(_BSD_SOURCE)
131# define _BSD_SOURCE
135** For MinGW, check to see if we can include the header file containing its
136** version information, among other things.  Normally, this internal MinGW
137** header file would [only] be included automatically by other MinGW header
138** files; however, the contained version information is now required by this
139** header file to work around binary compatibility issues (see below) and
140** this is the only known way to reliably obtain it.  This entire #if block
141** would be completely unnecessary if there was any other way of detecting
142** MinGW via their preprocessor (e.g. if they customized their GCC to define
143** some MinGW-specific macros).  When compiling for MinGW, either the
144** _HAVE_MINGW_H or _HAVE__MINGW_H (note the extra underscore) macro must be
145** defined; otherwise, detection of conditions specific to MinGW will be
146** disabled.
148#if defined(_HAVE_MINGW_H)
149# include "mingw.h"
150#elif defined(_HAVE__MINGW_H)
151# include "_mingw.h"
155** For MinGW version 4.x (and higher), check to see if the _USE_32BIT_TIME_T
156** define is required to maintain binary compatibility with the MSVC runtime
157** library in use (e.g. for Windows XP).
159#if !defined(_USE_32BIT_TIME_T) && !defined(_USE_64BIT_TIME_T) && \
160    defined(_WIN32) && !defined(_WIN64) && \
161    defined(__MINGW_MAJOR_VERSION) && __MINGW_MAJOR_VERSION >= 4 && \
162    defined(__MSVCRT__)
163# define _USE_32BIT_TIME_T
166/* The public SQLite interface.  The _FILE_OFFSET_BITS macro must appear
167** first in QNX.  Also, the _USE_32BIT_TIME_T macro must appear first for
168** MinGW.
170/************** Include sqlite3.h in the middle of sqliteInt.h ***************/
171/************** Begin file sqlite3.h *****************************************/
173** 2001 September 15
175** The author disclaims copyright to this source code.  In place of
176** a legal notice, here is a blessing:
178**    May you do good and not evil.
179**    May you find forgiveness for yourself and forgive others.
180**    May you share freely, never taking more than you give.
183** This header file defines the interface that the SQLite library
184** presents to client programs.  If a C-function, structure, datatype,
185** or constant definition does not appear in this file, then it is
186** not a published API of SQLite, is subject to change without
187** notice, and should not be referenced by programs that use SQLite.
189** Some of the definitions that are in this file are marked as
190** "experimental".  Experimental interfaces are normally new
191** features recently added to SQLite.  We do not anticipate changes
192** to experimental interfaces but reserve the right to make minor changes
193** if experience from use "in the wild" suggest such changes are prudent.
195** The official C-language API documentation for SQLite is derived
196** from comments in this file.  This file is the authoritative source
197** on how SQLite interfaces are suppose to operate.
199** The name of this file under configuration management is "sqlite.h.in".
200** The makefile makes some minor changes to this file (such as inserting
201** the version number) and changes its name to "sqlite3.h" as
202** part of the build process.
204#ifndef _SQLITE3_H_
205#define _SQLITE3_H_
206#include <stdarg.h>     /* Needed for the definition of va_list */
209** Make sure we can call this stuff from C++.
211#if 0
212extern "C" {
217** Add the ability to override 'extern'
219#ifndef SQLITE_EXTERN
220# define SQLITE_EXTERN extern
223#ifndef SQLITE_API
224# define SQLITE_API
229** These no-op macros are used in front of interfaces to mark those
230** interfaces as either deprecated or experimental.  New applications
231** should not use deprecated interfaces - they are supported for backwards
232** compatibility only.  Application writers should be aware that
233** experimental interfaces are subject to change in point releases.
235** These macros used to resolve to various kinds of compiler magic that
236** would generate warning messages when they were used.  But that
237** compiler magic ended up generating such a flurry of bug reports
238** that we have taken it all out and gone back to using simple
239** noop macros.
245** Ensure these symbols were not defined by some previous header file.
255** CAPI3REF: Compile-Time Library Version Numbers
257** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
258** evaluates to a string literal that is the SQLite version in the
259** format "X.Y.Z" where X is the major version number (always 3 for
260** SQLite3) and Y is the minor version number and Z is the release number.)^
261** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
262** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
263** numbers used in [SQLITE_VERSION].)^
264** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
265** be larger than the release from which it is derived.  Either Y will
266** be held constant and Z will be incremented or else Y will be incremented
267** and Z will be reset to zero.
269** Since version 3.6.18, SQLite source code has been stored in the
270** <a href="http://www.fossil-scm.org/">Fossil configuration management
271** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
272** a string which identifies a particular check-in of SQLite
273** within its configuration management system.  ^The SQLITE_SOURCE_ID
274** string contains the date and time of the check-in (UTC) and an SHA1
275** hash of the entire source tree.
277** See also: [sqlite3_libversion()],
278** [sqlite3_libversion_number()], [sqlite3_sourceid()],
279** [sqlite_version()] and [sqlite_source_id()].
281#define SQLITE_VERSION        ""
282#define SQLITE_VERSION_NUMBER 3008008
283#define SQLITE_SOURCE_ID      "2015-02-25 13:29:11 9d6c1880fb75660bbabd693175579529785f8a6b"
286** CAPI3REF: Run-Time Library Version Numbers
287** KEYWORDS: sqlite3_version, sqlite3_sourceid
289** These interfaces provide the same information as the [SQLITE_VERSION],
290** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
291** but are associated with the library instead of the header file.  ^(Cautious
292** programmers might include assert() statements in their application to
293** verify that values returned by these interfaces match the macros in
294** the header, and thus insure that the application is
295** compiled with matching library and header files.
297** <blockquote><pre>
298** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
299** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
300** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
301** </pre></blockquote>)^
303** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
304** macro.  ^The sqlite3_libversion() function returns a pointer to the
305** to the sqlite3_version[] string constant.  The sqlite3_libversion()
306** function is provided for use in DLLs since DLL users usually do not have
307** direct access to string constants within the DLL.  ^The
308** sqlite3_libversion_number() function returns an integer equal to
309** [SQLITE_VERSION_NUMBER].  ^The sqlite3_sourceid() function returns
310** a pointer to a string constant whose value is the same as the
311** [SQLITE_SOURCE_ID] C preprocessor macro.
313** See also: [sqlite_version()] and [sqlite_source_id()].
315SQLITE_API const char sqlite3_version[] = SQLITE_VERSION;
316SQLITE_API const char *sqlite3_libversion(void);
317SQLITE_API const char *sqlite3_sourceid(void);
318SQLITE_API int sqlite3_libversion_number(void);
321** CAPI3REF: Run-Time Library Compilation Options Diagnostics
323** ^The sqlite3_compileoption_used() function returns 0 or 1
324** indicating whether the specified option was defined at
325** compile time.  ^The SQLITE_ prefix may be omitted from the
326** option name passed to sqlite3_compileoption_used().
328** ^The sqlite3_compileoption_get() function allows iterating
329** over the list of options that were defined at compile time by
330** returning the N-th compile time option string.  ^If N is out of range,
331** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_
332** prefix is omitted from any strings returned by
333** sqlite3_compileoption_get().
335** ^Support for the diagnostic functions sqlite3_compileoption_used()
336** and sqlite3_compileoption_get() may be omitted by specifying the
337** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
339** See also: SQL functions [sqlite_compileoption_used()] and
340** [sqlite_compileoption_get()] and the [compile_options pragma].
343SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
344SQLITE_API const char *sqlite3_compileoption_get(int N);
348** CAPI3REF: Test To See If The Library Is Threadsafe
350** ^The sqlite3_threadsafe() function returns zero if and only if
351** SQLite was compiled with mutexing code omitted due to the
352** [SQLITE_THREADSAFE] compile-time option being set to 0.
354** SQLite can be compiled with or without mutexes.  When
355** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
356** are enabled and SQLite is threadsafe.  When the
357** [SQLITE_THREADSAFE] macro is 0,
358** the mutexes are omitted.  Without the mutexes, it is not safe
359** to use SQLite concurrently from more than one thread.
361** Enabling mutexes incurs a measurable performance penalty.
362** So if speed is of utmost importance, it makes sense to disable
363** the mutexes.  But for maximum safety, mutexes should be enabled.
364** ^The default behavior is for mutexes to be enabled.
366** This interface can be used by an application to make sure that the
367** version of SQLite that it is linking against was compiled with
368** the desired setting of the [SQLITE_THREADSAFE] macro.
370** This interface only reports on the compile-time mutex setting
371** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
372** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
373** can be fully or partially disabled using a call to [sqlite3_config()]
375** or [SQLITE_CONFIG_SERIALIZED].  ^(The return value of the
376** sqlite3_threadsafe() function shows only the compile-time setting of
377** thread safety, not any run-time changes to that setting made by
378** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
379** is unchanged by calls to sqlite3_config().)^
381** See the [threading mode] documentation for additional information.
383SQLITE_API int sqlite3_threadsafe(void);
386** CAPI3REF: Database Connection Handle
387** KEYWORDS: {database connection} {database connections}
389** Each open SQLite database is represented by a pointer to an instance of
390** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
391** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
392** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
393** and [sqlite3_close_v2()] are its destructors.  There are many other
394** interfaces (such as
395** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
396** [sqlite3_busy_timeout()] to name but three) that are methods on an
397** sqlite3 object.
399typedef struct sqlite3 sqlite3;
402** CAPI3REF: 64-Bit Integer Types
403** KEYWORDS: sqlite_int64 sqlite_uint64
405** Because there is no cross-platform way to specify 64-bit integer types
406** SQLite includes typedefs for 64-bit signed and unsigned integers.
408** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
409** The sqlite_int64 and sqlite_uint64 types are supported for backwards
410** compatibility only.
412** ^The sqlite3_int64 and sqlite_int64 types can store integer values
413** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
414** sqlite3_uint64 and sqlite_uint64 types can store integer values
415** between 0 and +18446744073709551615 inclusive.
417#ifdef SQLITE_INT64_TYPE
418  typedef SQLITE_INT64_TYPE sqlite_int64;
419  typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
420#elif defined(_MSC_VER) || defined(__BORLANDC__)
421  typedef __int64 sqlite_int64;
422  typedef unsigned __int64 sqlite_uint64;
424  typedef long long int sqlite_int64;
425  typedef unsigned long long int sqlite_uint64;
427typedef sqlite_int64 sqlite3_int64;
428typedef sqlite_uint64 sqlite3_uint64;
431** If compiling for a processor that lacks floating point support,
432** substitute integer for floating-point.
435# define double sqlite3_int64
439** CAPI3REF: Closing A Database Connection
441** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
442** for the [sqlite3] object.
443** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
444** the [sqlite3] object is successfully destroyed and all associated
445** resources are deallocated.
447** ^If the database connection is associated with unfinalized prepared
448** statements or unfinished sqlite3_backup objects then sqlite3_close()
449** will leave the database connection open and return [SQLITE_BUSY].
450** ^If sqlite3_close_v2() is called with unfinalized prepared statements
451** and/or unfinished sqlite3_backups, then the database connection becomes
452** an unusable "zombie" which will automatically be deallocated when the
453** last prepared statement is finalized or the last sqlite3_backup is
454** finished.  The sqlite3_close_v2() interface is intended for use with
455** host languages that are garbage collected, and where the order in which
456** destructors are called is arbitrary.
458** Applications should [sqlite3_finalize | finalize] all [prepared statements],
459** [sqlite3_blob_close | close] all [BLOB handles], and
460** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
461** with the [sqlite3] object prior to attempting to close the object.  ^If
462** sqlite3_close_v2() is called on a [database connection] that still has
463** outstanding [prepared statements], [BLOB handles], and/or
464** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
465** of resources is deferred until all [prepared statements], [BLOB handles],
466** and [sqlite3_backup] objects are also destroyed.
468** ^If an [sqlite3] object is destroyed while a transaction is open,
469** the transaction is automatically rolled back.
471** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
472** must be either a NULL
473** pointer or an [sqlite3] object pointer obtained
474** from [sqlite3_open()], [sqlite3_open16()], or
475** [sqlite3_open_v2()], and not previously closed.
476** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
477** argument is a harmless no-op.
479SQLITE_API int sqlite3_close(sqlite3*);
480SQLITE_API int sqlite3_close_v2(sqlite3*);
483** The type for a callback function.
484** This is legacy and deprecated.  It is included for historical
485** compatibility and is not documented.
487typedef int (*sqlite3_callback)(void*,int,char**, char**);
490** CAPI3REF: One-Step Query Execution Interface
492** The sqlite3_exec() interface is a convenience wrapper around
493** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
494** that allows an application to run multiple statements of SQL
495** without having to use a lot of C code.
497** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
498** semicolon-separate SQL statements passed into its 2nd argument,
499** in the context of the [database connection] passed in as its 1st
500** argument.  ^If the callback function of the 3rd argument to
501** sqlite3_exec() is not NULL, then it is invoked for each result row
502** coming out of the evaluated SQL statements.  ^The 4th argument to
503** sqlite3_exec() is relayed through to the 1st argument of each
504** callback invocation.  ^If the callback pointer to sqlite3_exec()
505** is NULL, then no callback is ever invoked and result rows are
506** ignored.
508** ^If an error occurs while evaluating the SQL statements passed into
509** sqlite3_exec(), then execution of the current statement stops and
510** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
511** is not NULL then any error message is written into memory obtained
512** from [sqlite3_malloc()] and passed back through the 5th parameter.
513** To avoid memory leaks, the application should invoke [sqlite3_free()]
514** on error message strings returned through the 5th parameter of
515** of sqlite3_exec() after the error message string is no longer needed.
516** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
517** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
518** NULL before returning.
520** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
521** routine returns SQLITE_ABORT without invoking the callback again and
522** without running any subsequent SQL statements.
524** ^The 2nd argument to the sqlite3_exec() callback function is the
525** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
526** callback is an array of pointers to strings obtained as if from
527** [sqlite3_column_text()], one for each column.  ^If an element of a
528** result row is NULL then the corresponding string pointer for the
529** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
530** sqlite3_exec() callback is an array of pointers to strings where each
531** entry represents the name of corresponding result column as obtained
532** from [sqlite3_column_name()].
534** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
535** to an empty string, or a pointer that contains only whitespace and/or
536** SQL comments, then no SQL statements are evaluated and the database
537** is not changed.
539** Restrictions:
541** <ul>
542** <li> The application must insure that the 1st parameter to sqlite3_exec()
543**      is a valid and open [database connection].
544** <li> The application must not close the [database connection] specified by
545**      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
546** <li> The application must not modify the SQL statement text passed into
547**      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
548** </ul>
550SQLITE_API int sqlite3_exec(
551  sqlite3*,                                  /* An open database */
552  const char *sql,                           /* SQL to be evaluated */
553  int (*callback)(void*,int,char**,char**),  /* Callback function */
554  void *,                                    /* 1st argument to callback */
555  char **errmsg                              /* Error msg written here */
559** CAPI3REF: Result Codes
560** KEYWORDS: {result code definitions}
562** Many SQLite functions return an integer result code from the set shown
563** here in order to indicate success or failure.
565** New error codes may be added in future versions of SQLite.
567** See also: [extended result code definitions]
569#define SQLITE_OK           0   /* Successful result */
570/* beginning-of-error-codes */
571#define SQLITE_ERROR        1   /* SQL error or missing database */
572#define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
573#define SQLITE_PERM         3   /* Access permission denied */
574#define SQLITE_ABORT        4   /* Callback routine requested an abort */
575#define SQLITE_BUSY         5   /* The database file is locked */
576#define SQLITE_LOCKED       6   /* A table in the database is locked */
577#define SQLITE_NOMEM        7   /* A malloc() failed */
578#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
579#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
580#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
581#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
582#define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
583#define SQLITE_FULL        13   /* Insertion failed because database is full */
584#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
585#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
586#define SQLITE_EMPTY       16   /* Database is empty */
587#define SQLITE_SCHEMA      17   /* The database schema changed */
588#define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
589#define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
590#define SQLITE_MISMATCH    20   /* Data type mismatch */
591#define SQLITE_MISUSE      21   /* Library used incorrectly */
592#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
593#define SQLITE_AUTH        23   /* Authorization denied */
594#define SQLITE_FORMAT      24   /* Auxiliary database format error */
595#define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
596#define SQLITE_NOTADB      26   /* File opened that is not a database file */
597#define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
598#define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
599#define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
600#define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
601/* end-of-error-codes */
604** CAPI3REF: Extended Result Codes
605** KEYWORDS: {extended result code definitions}
607** In its default configuration, SQLite API routines return one of 30 integer
608** [result codes].  However, experience has shown that many of
609** these result codes are too coarse-grained.  They do not provide as
610** much information about problems as programmers might like.  In an effort to
611** address this, newer versions of SQLite (version 3.3.8 and later) include
612** support for additional result codes that provide more detailed information
613** about errors. These [extended result codes] are enabled or disabled
614** on a per database connection basis using the
615** [sqlite3_extended_result_codes()] API.  Or, the extended code for
616** the most recent error can be obtained using
617** [sqlite3_extended_errcode()].
619#define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
620#define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
621#define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
622#define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
623#define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
624#define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
625#define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
626#define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
627#define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
628#define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
629#define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
630#define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
631#define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
633#define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
634#define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
635#define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
636#define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
637#define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
638#define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
639#define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
640#define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
641#define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
642#define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
643#define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
644#define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
646#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
647#define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
649#define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
652#define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
657#define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
671#define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
674** CAPI3REF: Flags For File Open Operations
676** These bit values are intended for use in the
677** 3rd parameter to the [sqlite3_open_v2()] interface and
678** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
680#define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
681#define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
682#define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
683#define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
684#define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
685#define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
686#define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
687#define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
688#define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
689#define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
690#define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
691#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
692#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
693#define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
694#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
695#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
696#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
697#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
698#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
699#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
701/* Reserved:                         0x00F00000 */
704** CAPI3REF: Device Characteristics
706** The xDeviceCharacteristics method of the [sqlite3_io_methods]
707** object returns an integer which is a vector of these
708** bit values expressing I/O characteristics of the mass storage
709** device that holds the file that the [sqlite3_io_methods]
710** refers to.
712** The SQLITE_IOCAP_ATOMIC property means that all writes of
713** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
714** mean that writes of blocks that are nnn bytes in size and
715** are aligned to an address which is an integer multiple of
716** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
717** that when data is appended to a file, the data is appended
718** first then the size of the file is extended, never the other
719** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
720** information is written to disk in the same order as calls
721** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
722** after reboot following a crash or power loss, the only bytes in a
723** file that were written at the application level might have changed
724** and that adjacent bytes, even bytes within the same sector are
725** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
726** flag indicate that a file cannot be deleted when open.  The
727** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
728** read-only media and cannot be changed even by processes with
729** elevated privileges.
731#define SQLITE_IOCAP_ATOMIC                 0x00000001
732#define SQLITE_IOCAP_ATOMIC512              0x00000002
733#define SQLITE_IOCAP_ATOMIC1K               0x00000004
734#define SQLITE_IOCAP_ATOMIC2K               0x00000008
735#define SQLITE_IOCAP_ATOMIC4K               0x00000010
736#define SQLITE_IOCAP_ATOMIC8K               0x00000020
737#define SQLITE_IOCAP_ATOMIC16K              0x00000040
738#define SQLITE_IOCAP_ATOMIC32K              0x00000080
739#define SQLITE_IOCAP_ATOMIC64K              0x00000100
740#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
741#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
744#define SQLITE_IOCAP_IMMUTABLE              0x00002000
747** CAPI3REF: File Locking Levels
749** SQLite uses one of these integer values as the second
750** argument to calls it makes to the xLock() and xUnlock() methods
751** of an [sqlite3_io_methods] object.
753#define SQLITE_LOCK_NONE          0
754#define SQLITE_LOCK_SHARED        1
755#define SQLITE_LOCK_RESERVED      2
756#define SQLITE_LOCK_PENDING       3
757#define SQLITE_LOCK_EXCLUSIVE     4
760** CAPI3REF: Synchronization Type Flags
762** When SQLite invokes the xSync() method of an
763** [sqlite3_io_methods] object it uses a combination of
764** these integer values as the second argument.
766** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
767** sync operation only needs to flush data to mass storage.  Inode
768** information need not be flushed. If the lower four bits of the flag
769** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
770** If the lower four bits equal SQLITE_SYNC_FULL, that means
771** to use Mac OS X style fullsync instead of fsync().
773** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
774** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
775** settings.  The [synchronous pragma] determines when calls to the
776** xSync VFS method occur and applies uniformly across all platforms.
777** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
778** energetic or rigorous or forceful the sync operations are and
779** only make a difference on Mac OSX for the default SQLite code.
780** (Third-party VFS implementations might also make the distinction
781** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
782** operating systems natively supported by SQLite, only Mac OSX
783** cares about the difference.)
785#define SQLITE_SYNC_NORMAL        0x00002
786#define SQLITE_SYNC_FULL          0x00003
787#define SQLITE_SYNC_DATAONLY      0x00010
790** CAPI3REF: OS Interface Open File Handle
792** An [sqlite3_file] object represents an open file in the
793** [sqlite3_vfs | OS interface layer].  Individual OS interface
794** implementations will
795** want to subclass this object by appending additional fields
796** for their own use.  The pMethods entry is a pointer to an
797** [sqlite3_io_methods] object that defines methods for performing
798** I/O operations on the open file.
800typedef struct sqlite3_file sqlite3_file;
801struct sqlite3_file {
802  const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
806** CAPI3REF: OS Interface File Virtual Methods Object
808** Every file opened by the [sqlite3_vfs.xOpen] method populates an
809** [sqlite3_file] object (or, more commonly, a subclass of the
810** [sqlite3_file] object) with a pointer to an instance of this object.
811** This object defines the methods used to perform various operations
812** against the open file represented by the [sqlite3_file] object.
814** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
815** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
816** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
817** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
818** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
819** to NULL.
821** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
822** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
823** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
824** flag may be ORed in to indicate that only the data of the file
825** and not its inode needs to be synced.
827** The integer values to xLock() and xUnlock() are one of
828** <ul>
829** <li> [SQLITE_LOCK_NONE],
830** <li> [SQLITE_LOCK_SHARED],
832** <li> [SQLITE_LOCK_PENDING], or
834** </ul>
835** xLock() increases the lock. xUnlock() decreases the lock.
836** The xCheckReservedLock() method checks whether any database connection,
837** either in this process or in some other process, is holding a RESERVED,
838** PENDING, or EXCLUSIVE lock on the file.  It returns true
839** if such a lock exists and false otherwise.
841** The xFileControl() method is a generic interface that allows custom
842** VFS implementations to directly control an open file using the
843** [sqlite3_file_control()] interface.  The second "op" argument is an
844** integer opcode.  The third argument is a generic pointer intended to
845** point to a structure that may contain arguments or space in which to
846** write return values.  Potential uses for xFileControl() might be
847** functions to enable blocking locks with timeouts, to change the
848** locking strategy (for example to use dot-file locks), to inquire
849** about the status of a lock, or to break stale locks.  The SQLite
850** core reserves all opcodes less than 100 for its own use.
851** A [file control opcodes | list of opcodes] less than 100 is available.
852** Applications that define a custom xFileControl method should use opcodes
853** greater than 100 to avoid conflicts.  VFS implementations should
854** return [SQLITE_NOTFOUND] for file control opcodes that they do not
855** recognize.
857** The xSectorSize() method returns the sector size of the
858** device that underlies the file.  The sector size is the
859** minimum write that can be performed without disturbing
860** other bytes in the file.  The xDeviceCharacteristics()
861** method returns a bit vector describing behaviors of the
862** underlying device:
864** <ul>
866** <li> [SQLITE_IOCAP_ATOMIC512]
876** </ul>
878** The SQLITE_IOCAP_ATOMIC property means that all writes of
879** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
880** mean that writes of blocks that are nnn bytes in size and
881** are aligned to an address which is an integer multiple of
882** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
883** that when data is appended to a file, the data is appended
884** first then the size of the file is extended, never the other
885** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
886** information is written to disk in the same order as calls
887** to xWrite().
889** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
890** in the unread portions of the buffer with zeros.  A VFS that
891** fails to zero-fill short reads might seem to work.  However,
892** failure to zero-fill short reads will eventually lead to
893** database corruption.
895typedef struct sqlite3_io_methods sqlite3_io_methods;
896struct sqlite3_io_methods {
897  int iVersion;
898  int (*xClose)(sqlite3_file*);
899  int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
900  int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
901  int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
902  int (*xSync)(sqlite3_file*, int flags);
903  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
904  int (*xLock)(sqlite3_file*, int);
905  int (*xUnlock)(sqlite3_file*, int);
906  int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
907  int (*xFileControl)(sqlite3_file*, int op, void *pArg);
908  int (*xSectorSize)(sqlite3_file*);
909  int (*xDeviceCharacteristics)(sqlite3_file*);
910  /* Methods above are valid for version 1 */
911  int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
912  int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
913  void (*xShmBarrier)(sqlite3_file*);
914  int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
915  /* Methods above are valid for version 2 */
916  int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
917  int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
918  /* Methods above are valid for version 3 */
919  /* Additional methods may be added in future releases */
923** CAPI3REF: Standard File Control Opcodes
924** KEYWORDS: {file control opcodes} {file control opcode}
926** These integer constants are opcodes for the xFileControl method
927** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
928** interface.
930** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
931** opcode causes the xFileControl method to write the current state of
932** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
934** into an integer that the pArg argument points to. This capability
935** is used during testing and only needs to be supported when SQLITE_TEST
936** is defined.
937** <ul>
939** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
940** layer a hint of how large the database file will grow to be during the
941** current transaction.  This hint is not guaranteed to be accurate but it
942** is often close.  The underlying VFS might choose to preallocate database
943** file space based on this hint in order to help writes to the database
944** file run faster.
947** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
948** extends and truncates the database file in chunks of a size specified
949** by the user. The fourth argument to [sqlite3_file_control()] should
950** point to an integer (type int) containing the new chunk-size to use
951** for the nominated database. Allocating database file space in large
952** chunks (say 1MB at a time), may reduce file-system fragmentation and
953** improve performance on some systems.
956** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
957** to the [sqlite3_file] object associated with a particular database
958** connection.  See the [sqlite3_file_control()] documentation for
959** additional information.
962** No longer in use.
964** <li>[[SQLITE_FCNTL_SYNC]]
965** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
966** sent to the VFS immediately before the xSync method is invoked on a
967** database file descriptor. Or, if the xSync method is not invoked
968** because the user has configured SQLite with
969** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
970** of the xSync method. In most cases, the pointer argument passed with
971** this file-control is NULL. However, if the database file is being synced
972** as part of a multi-database commit, the argument points to a nul-terminated
973** string containing the transactions master-journal file name. VFSes that
974** do not need this signal should silently ignore this opcode. Applications
975** should not call [sqlite3_file_control()] with this opcode as doing so may
976** disrupt the operation of the specialized VFSes that do require it.
979** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
980** and sent to the VFS after a transaction has been committed immediately
981** but before the database is unlocked. VFSes that do not need this signal
982** should silently ignore this opcode. Applications should not call
983** [sqlite3_file_control()] with this opcode as doing so may disrupt the
984** operation of the specialized VFSes that do require it.
987** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
988** retry counts and intervals for certain disk I/O operations for the
989** windows [VFS] in order to provide robustness in the presence of
990** anti-virus programs.  By default, the windows VFS will retry file read,
991** file write, and file delete operations up to 10 times, with a delay
992** of 25 milliseconds before the first retry and with the delay increasing
993** by an additional 25 milliseconds with each subsequent retry.  This
994** opcode allows these two values (10 retries and 25 milliseconds of delay)
995** to be adjusted.  The values are changed for all database connections
996** within the same process.  The argument is a pointer to an array of two
997** integers where the first integer i the new retry count and the second
998** integer is the delay.  If either integer is negative, then the setting
999** is not changed but instead the prior value of that setting is written
1000** into the array entry, allowing the current retry settings to be
1001** interrogated.  The zDbName parameter is ignored.
1004** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
1005** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
1006** write ahead log and shared memory files used for transaction control
1007** are automatically deleted when the latest connection to the database
1008** closes.  Setting persistent WAL mode causes those files to persist after
1009** close.  Persisting the files is useful when other processes that do not
1010** have write permission on the directory containing the database file want
1011** to read the database file, as the WAL and shared memory files must exist
1012** in order for the database to be readable.  The fourth parameter to
1013** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
1014** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
1015** WAL mode.  If the integer is -1, then it is overwritten with the current
1016** WAL persistence setting.
1019** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
1020** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
1021** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
1022** xDeviceCharacteristics methods. The fourth parameter to
1023** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
1024** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
1025** mode.  If the integer is -1, then it is overwritten with the current
1026** zero-damage mode setting.
1029** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
1030** a write transaction to indicate that, unless it is rolled back for some
1031** reason, the entire database file will be overwritten by the current
1032** transaction. This is used by VACUUM operations.
1035** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
1036** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
1037** final bottom-level VFS are written into memory obtained from
1038** [sqlite3_malloc()] and the result is stored in the char* variable
1039** that the fourth parameter of [sqlite3_file_control()] points to.
1040** The caller is responsible for freeing the memory when done.  As with
1041** all file-control actions, there is no guarantee that this will actually
1042** do anything.  Callers should initialize the char* variable to a NULL
1043** pointer in case this file-control is not implemented.  This file-control
1044** is intended for diagnostic use only.
1046** <li>[[SQLITE_FCNTL_PRAGMA]]
1047** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
1048** file control is sent to the open [sqlite3_file] object corresponding
1049** to the database file to which the pragma statement refers. ^The argument
1050** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
1051** pointers to strings (char**) in which the second element of the array
1052** is the name of the pragma and the third element is the argument to the
1053** pragma or NULL if the pragma has no argument.  ^The handler for an
1054** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
1055** of the char** argument point to a string obtained from [sqlite3_mprintf()]
1056** or the equivalent and that string will become the result of the pragma or
1057** the error message if the pragma fails. ^If the
1058** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
1059** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
1060** file control returns [SQLITE_OK], then the parser assumes that the
1061** VFS has handled the PRAGMA itself and the parser generates a no-op
1062** prepared statement.  ^If the [SQLITE_FCNTL_PRAGMA] file control returns
1063** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
1064** that the VFS encountered an error while handling the [PRAGMA] and the
1065** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
1066** file control occurs at the beginning of pragma statement analysis and so
1067** it is able to override built-in [PRAGMA] statements.
1071** file-control may be invoked by SQLite on the database file handle
1072** shortly after it is opened in order to provide a custom VFS with access
1073** to the connections busy-handler callback. The argument is of type (void **)
1074** - an array of two (void *) values. The first (void *) actually points
1075** to a function of type (int (*)(void *)). In order to invoke the connections
1076** busy-handler, this function should be invoked with the second (void *) in
1077** the array as the only argument. If it returns non-zero, then the operation
1078** should be retried. If it returns zero, the custom VFS should abandon the
1079** current operation.
1082** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
1083** to have SQLite generate a
1084** temporary filename using the same algorithm that is followed to generate
1085** temporary filenames for TEMP tables and other internal uses.  The
1086** argument should be a char** which will be filled with the filename
1087** written into memory obtained from [sqlite3_malloc()].  The caller should
1088** invoke [sqlite3_free()] on the result to avoid a memory leak.
1091** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
1092** maximum number of bytes that will be used for memory-mapped I/O.
1093** The argument is a pointer to a value of type sqlite3_int64 that
1094** is an advisory maximum number of bytes in the file to memory map.  The
1095** pointer is overwritten with the old value.  The limit is not changed if
1096** the value originally pointed to is negative, and so the current limit
1097** can be queried by passing in a pointer to a negative number.  This
1098** file-control is used internally to implement [PRAGMA mmap_size].
1100** <li>[[SQLITE_FCNTL_TRACE]]
1101** The [SQLITE_FCNTL_TRACE] file control provides advisory information
1102** to the VFS about what the higher layers of the SQLite stack are doing.
1103** This file control is used by some VFS activity tracing [shims].
1104** The argument is a zero-terminated string.  Higher layers in the
1105** SQLite stack may generate instances of this file control if
1106** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
1109** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
1110** pointer to an integer and it writes a boolean into that integer depending
1111** on whether or not the file has been renamed, moved, or deleted since it
1112** was first opened.
1115** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
1116** opcode causes the xFileControl method to swap the file handle with the one
1117** pointed to by the pArg argument.  This capability is used during testing
1118** and only needs to be supported when SQLITE_TEST is defined.
1120** </ul>
1122#define SQLITE_FCNTL_LOCKSTATE               1
1123#define SQLITE_GET_LOCKPROXYFILE             2
1124#define SQLITE_SET_LOCKPROXYFILE             3
1125#define SQLITE_LAST_ERRNO                    4
1126#define SQLITE_FCNTL_SIZE_HINT               5
1127#define SQLITE_FCNTL_CHUNK_SIZE              6
1128#define SQLITE_FCNTL_FILE_POINTER            7
1129#define SQLITE_FCNTL_SYNC_OMITTED            8
1130#define SQLITE_FCNTL_WIN32_AV_RETRY          9
1131#define SQLITE_FCNTL_PERSIST_WAL            10
1132#define SQLITE_FCNTL_OVERWRITE              11
1133#define SQLITE_FCNTL_VFSNAME                12
1135#define SQLITE_FCNTL_PRAGMA                 14
1136#define SQLITE_FCNTL_BUSYHANDLER            15
1137#define SQLITE_FCNTL_TEMPFILENAME           16
1138#define SQLITE_FCNTL_MMAP_SIZE              18
1139#define SQLITE_FCNTL_TRACE                  19
1140#define SQLITE_FCNTL_HAS_MOVED              20
1141#define SQLITE_FCNTL_SYNC                   21
1142#define SQLITE_FCNTL_COMMIT_PHASETWO        22
1143#define SQLITE_FCNTL_WIN32_SET_HANDLE       23
1146** CAPI3REF: Mutex Handle
1148** The mutex module within SQLite defines [sqlite3_mutex] to be an
1149** abstract type for a mutex object.  The SQLite core never looks
1150** at the internal representation of an [sqlite3_mutex].  It only
1151** deals with pointers to the [sqlite3_mutex] object.
1153** Mutexes are created using [sqlite3_mutex_alloc()].
1155typedef struct sqlite3_mutex sqlite3_mutex;
1158** CAPI3REF: OS Interface Object
1160** An instance of the sqlite3_vfs object defines the interface between
1161** the SQLite core and the underlying operating system.  The "vfs"
1162** in the name of the object stands for "virtual file system".  See
1163** the [VFS | VFS documentation] for further information.
1165** The value of the iVersion field is initially 1 but may be larger in
1166** future versions of SQLite.  Additional fields may be appended to this
1167** object when the iVersion value is increased.  Note that the structure
1168** of the sqlite3_vfs object changes in the transaction between
1169** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
1170** modified.
1172** The szOsFile field is the size of the subclassed [sqlite3_file]
1173** structure used by this VFS.  mxPathname is the maximum length of
1174** a pathname in this VFS.
1176** Registered sqlite3_vfs objects are kept on a linked list formed by
1177** the pNext pointer.  The [sqlite3_vfs_register()]
1178** and [sqlite3_vfs_unregister()] interfaces manage this list
1179** in a thread-safe way.  The [sqlite3_vfs_find()] interface
1180** searches the list.  Neither the application code nor the VFS
1181** implementation should use the pNext pointer.
1183** The pNext field is the only field in the sqlite3_vfs
1184** structure that SQLite will ever modify.  SQLite will only access
1185** or modify this field while holding a particular static mutex.
1186** The application should never modify anything within the sqlite3_vfs
1187** object once the object has been registered.
1189** The zName field holds the name of the VFS module.  The name must
1190** be unique across all VFS modules.
1192** [[sqlite3_vfs.xOpen]]
1193** ^SQLite guarantees that the zFilename parameter to xOpen
1194** is either a NULL pointer or string obtained
1195** from xFullPathname() with an optional suffix added.
1196** ^If a suffix is added to the zFilename parameter, it will
1197** consist of a single "-" character followed by no more than
1198** 11 alphanumeric and/or "-" characters.
1199** ^SQLite further guarantees that
1200** the string will be valid and unchanged until xClose() is
1201** called. Because of the previous sentence,
1202** the [sqlite3_file] can safely store a pointer to the
1203** filename if it needs to remember the filename for some reason.
1204** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1205** must invent its own temporary name for the file.  ^Whenever the
1206** xFilename parameter is NULL it will also be the case that the
1207** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1209** The flags argument to xOpen() includes all bits set in
1210** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
1211** or [sqlite3_open16()] is used, then flags includes at least
1213** If xOpen() opens a file read-only then it sets *pOutFlags to
1214** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
1216** ^(SQLite will also add one of the following flags to the xOpen()
1217** call, depending on the object being opened:
1219** <ul>
1220** <li>  [SQLITE_OPEN_MAIN_DB]
1222** <li>  [SQLITE_OPEN_TEMP_DB]
1227** <li>  [SQLITE_OPEN_WAL]
1228** </ul>)^
1230** The file I/O implementation can use the object type flags to
1231** change the way it deals with files.  For example, an application
1232** that does not care about crash recovery or rollback might make
1233** the open of a journal file a no-op.  Writes to this journal would
1234** also be no-ops, and any attempt to read the journal would return
1235** SQLITE_IOERR.  Or the implementation might recognize that a database
1236** file will be doing page-aligned sector reads and writes in a random
1237** order and set up its I/O subsystem accordingly.
1239** SQLite might also add one of the following flags to the xOpen method:
1241** <ul>
1244** </ul>
1246** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1247** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
1248** will be set for TEMP databases and their journals, transient
1249** databases, and subjournals.
1251** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1252** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1253** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1254** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1255** SQLITE_OPEN_CREATE, is used to indicate that file should always
1256** be created, and that it is an error if it already exists.
1257** It is <i>not</i> used to indicate the file should be opened
1258** for exclusive access.
1260** ^At least szOsFile bytes of memory are allocated by SQLite
1261** to hold the  [sqlite3_file] structure passed as the third
1262** argument to xOpen.  The xOpen method does not have to
1263** allocate the structure; it should just fill it in.  Note that
1264** the xOpen method must set the sqlite3_file.pMethods to either
1265** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
1266** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
1267** element will be valid after xOpen returns regardless of the success
1268** or failure of the xOpen call.
1270** [[sqlite3_vfs.xAccess]]
1271** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1272** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1273** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1274** to test whether a file is at least readable.   The file can be a
1275** directory.
1277** ^SQLite will always allocate at least mxPathname+1 bytes for the
1278** output buffer xFullPathname.  The exact size of the output buffer
1279** is also passed as a parameter to both  methods. If the output buffer
1280** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1281** handled as a fatal error by SQLite, vfs implementations should endeavor
1282** to prevent this by setting mxPathname to a sufficiently large value.
1284** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1285** interfaces are not strictly a part of the filesystem, but they are
1286** included in the VFS structure for completeness.
1287** The xRandomness() function attempts to return nBytes bytes
1288** of good-quality randomness into zOut.  The return value is
1289** the actual number of bytes of randomness obtained.
1290** The xSleep() method causes the calling thread to sleep for at
1291** least the number of microseconds given.  ^The xCurrentTime()
1292** method returns a Julian Day Number for the current date and time as
1293** a floating point value.
1294** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1295** Day Number multiplied by 86400000 (the number of milliseconds in
1296** a 24-hour day).
1297** ^SQLite will use the xCurrentTimeInt64() method to get the current
1298** date and time if that method is available (if iVersion is 2 or
1299** greater and the function pointer is not NULL) and will fall back
1300** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1302** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1303** are not used by the SQLite core.  These optional interfaces are provided
1304** by some VFSes to facilitate testing of the VFS code. By overriding
1305** system calls with functions under its control, a test program can
1306** simulate faults and error conditions that would otherwise be difficult
1307** or impossible to induce.  The set of system calls that can be overridden
1308** varies from one VFS to another, and from one version of the same VFS to the
1309** next.  Applications that use these interfaces must be prepared for any
1310** or all of these interfaces to be NULL or for their behavior to change
1311** from one release to the next.  Applications must not attempt to access
1312** any of these methods if the iVersion of the VFS is less than 3.
1314typedef struct sqlite3_vfs sqlite3_vfs;
1315typedef void (*sqlite3_syscall_ptr)(void);
1316struct sqlite3_vfs {
1317  int iVersion;            /* Structure version number (currently 3) */
1318  int szOsFile;            /* Size of subclassed sqlite3_file */
1319  int mxPathname;          /* Maximum file pathname length */
1320  sqlite3_vfs *pNext;      /* Next registered VFS */
1321  const char *zName;       /* Name of this virtual file system */
1322  void *pAppData;          /* Pointer to application-specific data */
1323  int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1324               int flags, int *pOutFlags);
1325  int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1326  int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1327  int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1328  void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1329  void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1330  void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1331  void (*xDlClose)(sqlite3_vfs*, void*);
1332  int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1333  int (*xSleep)(sqlite3_vfs*, int microseconds);
1334  int (*xCurrentTime)(sqlite3_vfs*, double*);
1335  int (*xGetLastError)(sqlite3_vfs*, int, char *);
1336  /*
1337  ** The methods above are in version 1 of the sqlite_vfs object
1338  ** definition.  Those that follow are added in version 2 or later
1339  */
1340  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1341  /*
1342  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1343  ** Those below are for version 3 and greater.
1344  */
1345  int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1346  sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1347  const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1348  /*
1349  ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1350  ** New fields may be appended in figure versions.  The iVersion
1351  ** value will increment whenever this happens.
1352  */
1356** CAPI3REF: Flags for the xAccess VFS method
1358** These integer constants can be used as the third parameter to
1359** the xAccess method of an [sqlite3_vfs] object.  They determine
1360** what kind of permissions the xAccess method is looking for.
1361** With SQLITE_ACCESS_EXISTS, the xAccess method
1362** simply checks whether the file exists.
1363** With SQLITE_ACCESS_READWRITE, the xAccess method
1364** checks whether the named directory is both readable and writable
1365** (in other words, if files can be added, removed, and renamed within
1366** the directory).
1367** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1368** [temp_store_directory pragma], though this could change in a future
1369** release of SQLite.
1370** With SQLITE_ACCESS_READ, the xAccess method
1371** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
1372** currently unused, though it might be used in a future release of
1373** SQLite.
1375#define SQLITE_ACCESS_EXISTS    0
1376#define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
1377#define SQLITE_ACCESS_READ      2   /* Unused */
1380** CAPI3REF: Flags for the xShmLock VFS method
1382** These integer constants define the various locking operations
1383** allowed by the xShmLock method of [sqlite3_io_methods].  The
1384** following are the only legal combinations of flags to the
1385** xShmLock method:
1387** <ul>
1392** </ul>
1394** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1395** was given on the corresponding lock.
1397** The xShmLock method can transition between unlocked and SHARED or
1398** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
1399** and EXCLUSIVE.
1401#define SQLITE_SHM_UNLOCK       1
1402#define SQLITE_SHM_LOCK         2
1403#define SQLITE_SHM_SHARED       4
1404#define SQLITE_SHM_EXCLUSIVE    8
1407** CAPI3REF: Maximum xShmLock index
1409** The xShmLock method on [sqlite3_io_methods] may use values
1410** between 0 and this upper bound as its "offset" argument.
1411** The SQLite core will never attempt to acquire or release a
1412** lock outside of this range
1414#define SQLITE_SHM_NLOCK        8
1418** CAPI3REF: Initialize The SQLite Library
1420** ^The sqlite3_initialize() routine initializes the
1421** SQLite library.  ^The sqlite3_shutdown() routine
1422** deallocates any resources that were allocated by sqlite3_initialize().
1423** These routines are designed to aid in process initialization and
1424** shutdown on embedded systems.  Workstation applications using
1425** SQLite normally do not need to invoke either of these routines.
1427** A call to sqlite3_initialize() is an "effective" call if it is
1428** the first time sqlite3_initialize() is invoked during the lifetime of
1429** the process, or if it is the first time sqlite3_initialize() is invoked
1430** following a call to sqlite3_shutdown().  ^(Only an effective call
1431** of sqlite3_initialize() does any initialization.  All other calls
1432** are harmless no-ops.)^
1434** A call to sqlite3_shutdown() is an "effective" call if it is the first
1435** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
1436** an effective call to sqlite3_shutdown() does any deinitialization.
1437** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1439** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1440** is not.  The sqlite3_shutdown() interface must only be called from a
1441** single thread.  All open [database connections] must be closed and all
1442** other SQLite resources must be deallocated prior to invoking
1443** sqlite3_shutdown().
1445** Among other things, ^sqlite3_initialize() will invoke
1446** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
1447** will invoke sqlite3_os_end().
1449** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1450** ^If for some reason, sqlite3_initialize() is unable to initialize
1451** the library (perhaps it is unable to allocate a needed resource such
1452** as a mutex) it returns an [error code] other than [SQLITE_OK].
1454** ^The sqlite3_initialize() routine is called internally by many other
1455** SQLite interfaces so that an application usually does not need to
1456** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
1457** calls sqlite3_initialize() so the SQLite library will be automatically
1458** initialized when [sqlite3_open()] is called if it has not be initialized
1459** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1460** compile-time option, then the automatic calls to sqlite3_initialize()
1461** are omitted and the application must call sqlite3_initialize() directly
1462** prior to using any other SQLite interface.  For maximum portability,
1463** it is recommended that applications always invoke sqlite3_initialize()
1464** directly prior to using any other SQLite interface.  Future releases
1465** of SQLite may require this.  In other words, the behavior exhibited
1466** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1467** default behavior in some future release of SQLite.
1469** The sqlite3_os_init() routine does operating-system specific
1470** initialization of the SQLite library.  The sqlite3_os_end()
1471** routine undoes the effect of sqlite3_os_init().  Typical tasks
1472** performed by these routines include allocation or deallocation
1473** of static resources, initialization of global variables,
1474** setting up a default [sqlite3_vfs] module, or setting up
1475** a default configuration using [sqlite3_config()].
1477** The application should never invoke either sqlite3_os_init()
1478** or sqlite3_os_end() directly.  The application should only invoke
1479** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
1480** interface is called automatically by sqlite3_initialize() and
1481** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
1482** implementations for sqlite3_os_init() and sqlite3_os_end()
1483** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1484** When [custom builds | built for other platforms]
1485** (using the [SQLITE_OS_OTHER=1] compile-time
1486** option) the application must supply a suitable implementation for
1487** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
1488** implementation of sqlite3_os_init() or sqlite3_os_end()
1489** must return [SQLITE_OK] on success and some other [error code] upon
1490** failure.
1492SQLITE_API int sqlite3_initialize(void);
1493SQLITE_API int sqlite3_shutdown(void);
1494SQLITE_API int sqlite3_os_init(void);
1495SQLITE_API int sqlite3_os_end(void);
1498** CAPI3REF: Configuring The SQLite Library
1500** The sqlite3_config() interface is used to make global configuration
1501** changes to SQLite in order to tune SQLite to the specific needs of
1502** the application.  The default configuration is recommended for most
1503** applications and so this routine is usually not necessary.  It is
1504** provided to support rare applications with unusual needs.
1506** The sqlite3_config() interface is not threadsafe.  The application
1507** must insure that no other SQLite interfaces are invoked by other
1508** threads while sqlite3_config() is running.  Furthermore, sqlite3_config()
1509** may only be invoked prior to library initialization using
1510** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1511** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1512** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1513** Note, however, that ^sqlite3_config() can be called as part of the
1514** implementation of an application-defined [sqlite3_os_init()].
1516** The first argument to sqlite3_config() is an integer
1517** [configuration option] that determines
1518** what property of SQLite is to be configured.  Subsequent arguments
1519** vary depending on the [configuration option]
1520** in the first argument.
1522** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1523** ^If the option is unknown or SQLite is unable to set the option
1524** then this routine returns a non-zero [error code].
1526SQLITE_API int sqlite3_config(int, ...);
1529** CAPI3REF: Configure database connections
1531** The sqlite3_db_config() interface is used to make configuration
1532** changes to a [database connection].  The interface is similar to
1533** [sqlite3_config()] except that the changes apply to a single
1534** [database connection] (specified in the first argument).
1536** The second argument to sqlite3_db_config(D,V,...)  is the
1537** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1538** that indicates what aspect of the [database connection] is being configured.
1539** Subsequent arguments vary depending on the configuration verb.
1541** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1542** the call is considered successful.
1544SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1547** CAPI3REF: Memory Allocation Routines
1549** An instance of this object defines the interface between SQLite
1550** and low-level memory allocation routines.
1552** This object is used in only one place in the SQLite interface.
1553** A pointer to an instance of this object is the argument to
1554** [sqlite3_config()] when the configuration option is
1556** By creating an instance of this object
1557** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1558** during configuration, an application can specify an alternative
1559** memory allocation subsystem for SQLite to use for all of its
1560** dynamic memory needs.
1562** Note that SQLite comes with several [built-in memory allocators]
1563** that are perfectly adequate for the overwhelming majority of applications
1564** and that this object is only useful to a tiny minority of applications
1565** with specialized memory allocation requirements.  This object is
1566** also used during testing of SQLite in order to specify an alternative
1567** memory allocator that simulates memory out-of-memory conditions in
1568** order to verify that SQLite recovers gracefully from such
1569** conditions.
1571** The xMalloc, xRealloc, and xFree methods must work like the
1572** malloc(), realloc() and free() functions from the standard C library.
1573** ^SQLite guarantees that the second argument to
1574** xRealloc is always a value returned by a prior call to xRoundup.
1576** xSize should return the allocated size of a memory allocation
1577** previously obtained from xMalloc or xRealloc.  The allocated size
1578** is always at least as big as the requested size but may be larger.
1580** The xRoundup method returns what would be the allocated size of
1581** a memory allocation given a particular requested size.  Most memory
1582** allocators round up memory allocations at least to the next multiple
1583** of 8.  Some allocators round up to a larger multiple or to a power of 2.
1584** Every memory allocation request coming in through [sqlite3_malloc()]
1585** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
1586** that causes the corresponding memory allocation to fail.
1588** The xInit method initializes the memory allocator.  For example,
1589** it might allocate any require mutexes or initialize internal data
1590** structures.  The xShutdown method is invoked (indirectly) by
1591** [sqlite3_shutdown()] and should deallocate any resources acquired
1592** by xInit.  The pAppData pointer is used as the only parameter to
1593** xInit and xShutdown.
1595** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1596** the xInit method, so the xInit method need not be threadsafe.  The
1597** xShutdown method is only called from [sqlite3_shutdown()] so it does
1598** not need to be threadsafe either.  For all other methods, SQLite
1599** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1600** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1601** it is by default) and so the methods are automatically serialized.
1602** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1603** methods must be threadsafe or else make their own arrangements for
1604** serialization.
1606** SQLite will never invoke xInit() more than once without an intervening
1607** call to xShutdown().
1609typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1610struct sqlite3_mem_methods {
1611  void *(*xMalloc)(int);         /* Memory allocation function */
1612  void (*xFree)(void*);          /* Free a prior allocation */
1613  void *(*xRealloc)(void*,int);  /* Resize an allocation */
1614  int (*xSize)(void*);           /* Return the size of an allocation */
1615  int (*xRoundup)(int);          /* Round up request size to allocation size */
1616  int (*xInit)(void*);           /* Initialize the memory allocator */
1617  void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
1618  void *pAppData;                /* Argument to xInit() and xShutdown() */
1622** CAPI3REF: Configuration Options
1623** KEYWORDS: {configuration option}
1625** These constants are the available integer configuration options that
1626** can be passed as the first argument to the [sqlite3_config()] interface.
1628** New configuration options may be added in future releases of SQLite.
1629** Existing configuration options might be discontinued.  Applications
1630** should check the return code from [sqlite3_config()] to make sure that
1631** the call worked.  The [sqlite3_config()] interface will return a
1632** non-zero [error code] if a discontinued or unsupported configuration option
1633** is invoked.
1635** <dl>
1637** <dd>There are no arguments to this option.  ^This option sets the
1638** [threading mode] to Single-thread.  In other words, it disables
1639** all mutexing and puts SQLite into a mode where it can only be used
1640** by a single thread.   ^If SQLite is compiled with
1641** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1642** it is not possible to change the [threading mode] from its default
1643** value of Single-thread and so [sqlite3_config()] will return
1645** configuration option.</dd>
1648** <dd>There are no arguments to this option.  ^This option sets the
1649** [threading mode] to Multi-thread.  In other words, it disables
1650** mutexing on [database connection] and [prepared statement] objects.
1651** The application is responsible for serializing access to
1652** [database connections] and [prepared statements].  But other mutexes
1653** are enabled so that SQLite will be safe to use in a multi-threaded
1654** environment as long as no two threads attempt to use the same
1655** [database connection] at the same time.  ^If SQLite is compiled with
1656** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1657** it is not possible to set the Multi-thread [threading mode] and
1658** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1659** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1662** <dd>There are no arguments to this option.  ^This option sets the
1663** [threading mode] to Serialized. In other words, this option enables
1664** all mutexes including the recursive
1665** mutexes on [database connection] and [prepared statement] objects.
1666** In this mode (which is the default when SQLite is compiled with
1667** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1668** to [database connections] and [prepared statements] so that the
1669** application is free to use the same [database connection] or the
1670** same [prepared statement] in different threads at the same time.
1671** ^If SQLite is compiled with
1672** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1673** it is not possible to set the Serialized [threading mode] and
1674** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1675** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1678** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1679** a pointer to an instance of the [sqlite3_mem_methods] structure.
1680** The argument specifies
1681** alternative low-level memory allocation routines to be used in place of
1682** the memory allocation routines built into SQLite.)^ ^SQLite makes
1683** its own private copy of the content of the [sqlite3_mem_methods] structure
1684** before the [sqlite3_config()] call returns.</dd>
1687** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1688** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1689** The [sqlite3_mem_methods]
1690** structure is filled with the currently defined memory allocation routines.)^
1691** This option can be used to overload the default memory allocation
1692** routines with a wrapper that simulations memory allocation failure or
1693** tracks memory usage, for example. </dd>
1696** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1697** interpreted as a boolean, which enables or disables the collection of
1698** memory allocation statistics. ^(When memory allocation statistics are
1699** disabled, the following SQLite interfaces become non-operational:
1700**   <ul>
1701**   <li> [sqlite3_memory_used()]
1702**   <li> [sqlite3_memory_highwater()]
1703**   <li> [sqlite3_soft_heap_limit64()]
1704**   <li> [sqlite3_status()]
1705**   </ul>)^
1706** ^Memory allocation statistics are enabled by default unless SQLite is
1707** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1708** allocation statistics are disabled by default.
1709** </dd>
1712** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer
1713** that SQLite can use for scratch memory.  ^(There are three arguments
1714** to SQLITE_CONFIG_SCRATCH:  A pointer an 8-byte
1715** aligned memory buffer from which the scratch allocations will be
1716** drawn, the size of each scratch allocation (sz),
1717** and the maximum number of scratch allocations (N).)^
1718** The first argument must be a pointer to an 8-byte aligned buffer
1719** of at least sz*N bytes of memory.
1720** ^SQLite will not use more than one scratch buffers per thread.
1721** ^SQLite will never request a scratch buffer that is more than 6
1722** times the database page size.
1723** ^If SQLite needs needs additional
1724** scratch memory beyond what is provided by this configuration option, then
1725** [sqlite3_malloc()] will be used to obtain the memory needed.<p>
1726** ^When the application provides any amount of scratch memory using
1727** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large
1728** [sqlite3_malloc|heap allocations].
1729** This can help [Robson proof|prevent memory allocation failures] due to heap
1730** fragmentation in low-memory embedded systems.
1731** </dd>
1734** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a static memory buffer
1735** that SQLite can use for the database page cache with the default page
1736** cache implementation.
1737** This configuration should not be used if an application-define page
1738** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]
1739** configuration option.
1740** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1741** 8-byte aligned
1742** memory, the size of each page buffer (sz), and the number of pages (N).
1743** The sz argument should be the size of the largest database page
1744** (a power of two between 512 and 65536) plus some extra bytes for each
1745** page header.  ^The number of extra bytes needed by the page header
1746** can be determined using the [SQLITE_CONFIG_PCACHE_HDRSZ] option
1747** to [sqlite3_config()].
1748** ^It is harmless, apart from the wasted memory,
1749** for the sz parameter to be larger than necessary.  The first
1750** argument should pointer to an 8-byte aligned block of memory that
1751** is at least sz*N bytes of memory, otherwise subsequent behavior is
1752** undefined.
1753** ^SQLite will use the memory provided by the first argument to satisfy its
1754** memory needs for the first N pages that it adds to cache.  ^If additional
1755** page cache memory is needed beyond what is provided by this option, then
1756** SQLite goes to [sqlite3_malloc()] for the additional storage space.</dd>
1759** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1760** that SQLite will use for all of its dynamic memory allocation needs
1761** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and
1763** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1764** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1765** [SQLITE_ERROR] if invoked otherwise.
1766** ^There are three arguments to SQLITE_CONFIG_HEAP:
1767** An 8-byte aligned pointer to the memory,
1768** the number of bytes in the memory buffer, and the minimum allocation size.
1769** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1770** to using its default memory allocator (the system malloc() implementation),
1771** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
1772** memory pointer is not NULL then the alternative memory
1773** allocator is engaged to handle all of SQLites memory allocation needs.
1774** The first pointer (the memory pointer) must be aligned to an 8-byte
1775** boundary or subsequent behavior of SQLite will be undefined.
1776** The minimum allocation size is capped at 2**12. Reasonable values
1777** for the minimum allocation size are 2**5 through 2**8.</dd>
1780** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1781** pointer to an instance of the [sqlite3_mutex_methods] structure.
1782** The argument specifies alternative low-level mutex routines to be used
1783** in place the mutex routines built into SQLite.)^  ^SQLite makes a copy of
1784** the content of the [sqlite3_mutex_methods] structure before the call to
1785** [sqlite3_config()] returns. ^If SQLite is compiled with
1786** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1787** the entire mutexing subsystem is omitted from the build and hence calls to
1788** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1789** return [SQLITE_ERROR].</dd>
1792** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1793** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
1794** [sqlite3_mutex_methods]
1795** structure is filled with the currently defined mutex routines.)^
1796** This option can be used to overload the default mutex allocation
1797** routines with a wrapper used to track mutex usage for performance
1798** profiling or testing, for example.   ^If SQLite is compiled with
1799** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1800** the entire mutexing subsystem is omitted from the build and hence calls to
1801** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1802** return [SQLITE_ERROR].</dd>
1805** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1806** the default size of lookaside memory on each [database connection].
1807** The first argument is the
1808** size of each lookaside buffer slot and the second is the number of
1809** slots allocated to each database connection.)^  ^(SQLITE_CONFIG_LOOKASIDE
1810** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1811** option to [sqlite3_db_config()] can be used to change the lookaside
1812** configuration on individual connections.)^ </dd>
1815** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1816** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
1817** the interface to a custom page cache implementation.)^
1818** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1821** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1822** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies of
1823** the current page cache implementation into that object.)^ </dd>
1826** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1827** global [error log].
1828** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1829** function with a call signature of void(*)(void*,int,const char*),
1830** and a pointer to void. ^If the function pointer is not NULL, it is
1831** invoked by [sqlite3_log()] to process each logging event.  ^If the
1832** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1833** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1834** passed through as the first parameter to the application-defined logger
1835** function whenever that function is invoked.  ^The second parameter to
1836** the logger function is a copy of the first parameter to the corresponding
1837** [sqlite3_log()] call and is intended to be a [result code] or an
1838** [extended result code].  ^The third parameter passed to the logger is
1839** log message after formatting via [sqlite3_snprintf()].
1840** The SQLite logging interface is not reentrant; the logger function
1841** supplied by the application must not invoke any SQLite interface.
1842** In a multi-threaded application, the application-defined logger
1843** function must be threadsafe. </dd>
1846** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1847** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1848** then URI handling is globally disabled.)^ ^If URI handling is globally
1849** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1850** [sqlite3_open16()] or
1851** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1852** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1853** connection is opened. ^If it is globally disabled, filenames are
1854** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1855** database connection is opened. ^(By default, URI handling is globally
1856** disabled. The default value may be changed by compiling with the
1857** [SQLITE_USE_URI] symbol defined.)^
1860** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1861** argument which is interpreted as a boolean in order to enable or disable
1862** the use of covering indices for full table scans in the query optimizer.
1863** ^The default setting is determined
1864** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1865** if that compile-time option is omitted.
1866** The ability to disable the use of covering indices for full table scans
1867** is because some incorrectly coded legacy applications might malfunction
1868** when the optimization is enabled.  Providing the ability to
1869** disable the optimization allows the older, buggy application code to work
1870** without change even with newer versions of SQLite.
1874** <dd> These options are obsolete and should not be used by new code.
1875** They are retained for backwards compatibility but are now no-ops.
1876** </dd>
1880** <dd>This option is only available if sqlite is compiled with the
1881** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1882** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1883** The second should be of type (void*). The callback is invoked by the library
1884** in three separate circumstances, identified by the value passed as the
1885** fourth parameter. If the fourth parameter is 0, then the database connection
1886** passed as the second argument has just been opened. The third argument
1887** points to a buffer containing the name of the main database file. If the
1888** fourth parameter is 1, then the SQL statement that the third parameter
1889** points to has just been executed. Or, if the fourth parameter is 2, then
1890** the connection being passed as the second parameter is being closed. The
1891** third parameter is passed NULL In this case.  An example of using this
1892** configuration option can be seen in the "test_sqllog.c" source file in
1893** the canonical SQLite source tree.</dd>
1897** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1898** that are the default mmap size limit (the default setting for
1899** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1900** ^The default setting can be overridden by each database connection using
1901** either the [PRAGMA mmap_size] command, or by using the
1902** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
1903** will be silently truncated if necessary so that it does not exceed the
1904** compile-time maximum mmap size set by the
1905** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1906** ^If either argument to this option is negative, then that argument is
1907** changed to its compile-time default.
1911** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
1912** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
1913** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1914** that specifies the maximum size of the created heap.
1915** </dl>
1919** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
1920** is a pointer to an integer and writes into that integer the number of extra
1921** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
1922** The amount of extra space required can change depending on the compiler,
1923** target platform, and SQLite version.
1927** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
1928** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
1929** sorter to that integer.  The default minimum PMA Size is set by the
1930** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
1931** to help with sort operations when multithreaded sorting
1932** is enabled (using the [PRAGMA threads] command) and the amount of content
1933** to be sorted exceeds the page size times the minimum of the
1934** [PRAGMA cache_size] setting and this value.
1935** </dl>
1937#define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
1938#define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
1939#define SQLITE_CONFIG_SERIALIZED    3  /* nil */
1940#define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
1941#define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
1942#define SQLITE_CONFIG_SCRATCH       6  /* void*, int sz, int N */
1943#define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
1944#define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
1945#define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
1946#define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
1947#define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
1948/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1949#define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
1950#define SQLITE_CONFIG_PCACHE       14  /* no-op */
1951#define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
1952#define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
1953#define SQLITE_CONFIG_URI          17  /* int */
1954#define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
1955#define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
1956#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
1957#define SQLITE_CONFIG_SQLLOG       21  /* xSqllog, void* */
1958#define SQLITE_CONFIG_MMAP_SIZE    22  /* sqlite3_int64, sqlite3_int64 */
1959#define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
1960#define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
1961#define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
1964** CAPI3REF: Database Connection Configuration Options
1966** These constants are the available integer configuration options that
1967** can be passed as the second argument to the [sqlite3_db_config()] interface.
1969** New configuration options may be added in future releases of SQLite.
1970** Existing configuration options might be discontinued.  Applications
1971** should check the return code from [sqlite3_db_config()] to make sure that
1972** the call worked.  ^The [sqlite3_db_config()] interface will return a
1973** non-zero [error code] if a discontinued or unsupported configuration option
1974** is invoked.
1976** <dl>
1978** <dd> ^This option takes three additional arguments that determine the
1979** [lookaside memory allocator] configuration for the [database connection].
1980** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1981** pointer to a memory buffer to use for lookaside memory.
1982** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1983** may be NULL in which case SQLite will allocate the
1984** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1985** size of each lookaside buffer slot.  ^The third argument is the number of
1986** slots.  The size of the buffer in the first argument must be greater than
1987** or equal to the product of the second and third arguments.  The buffer
1988** must be aligned to an 8-byte boundary.  ^If the second argument to
1989** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1990** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
1991** configuration for a database connection can only be changed when that
1992** connection is not currently using lookaside memory, or in other words
1993** when the "current value" returned by
1994** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1995** Any attempt to change the lookaside memory configuration when lookaside
1996** memory is in use leaves the configuration unchanged and returns
1997** [SQLITE_BUSY].)^</dd>
2000** <dd> ^This option is used to enable or disable the enforcement of
2001** [foreign key constraints].  There should be two additional arguments.
2002** The first argument is an integer which is 0 to disable FK enforcement,
2003** positive to enable FK enforcement or negative to leave FK enforcement
2004** unchanged.  The second parameter is a pointer to an integer into which
2005** is written 0 or 1 to indicate whether FK enforcement is off or on
2006** following this call.  The second parameter may be a NULL pointer, in
2007** which case the FK enforcement setting is not reported back. </dd>
2010** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
2011** There should be two additional arguments.
2012** The first argument is an integer which is 0 to disable triggers,
2013** positive to enable triggers or negative to leave the setting unchanged.
2014** The second parameter is a pointer to an integer into which
2015** is written 0 or 1 to indicate whether triggers are disabled or enabled
2016** following this call.  The second parameter may be a NULL pointer, in
2017** which case the trigger setting is not reported back. </dd>
2019** </dl>
2021#define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */
2022#define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */
2023#define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */
2027** CAPI3REF: Enable Or Disable Extended Result Codes
2029** ^The sqlite3_extended_result_codes() routine enables or disables the
2030** [extended result codes] feature of SQLite. ^The extended result
2031** codes are disabled by default for historical compatibility.
2033SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
2036** CAPI3REF: Last Insert Rowid
2038** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
2039** has a unique 64-bit signed
2040** integer key called the [ROWID | "rowid"]. ^The rowid is always available
2041** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
2042** names are not also used by explicitly declared columns. ^If
2043** the table has a column of type [INTEGER PRIMARY KEY] then that column
2044** is another alias for the rowid.
2046** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the
2047** most recent successful [INSERT] into a rowid table or [virtual table]
2048** on database connection D.
2049** ^Inserts into [WITHOUT ROWID] tables are not recorded.
2050** ^If no successful [INSERT]s into rowid tables
2051** have ever occurred on the database connection D,
2052** then sqlite3_last_insert_rowid(D) returns zero.
2054** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
2055** method, then this routine will return the [rowid] of the inserted
2056** row as long as the trigger or virtual table method is running.
2057** But once the trigger or virtual table method ends, the value returned
2058** by this routine reverts to what it was before the trigger or virtual
2059** table method began.)^
2061** ^An [INSERT] that fails due to a constraint violation is not a
2062** successful [INSERT] and does not change the value returned by this
2064** and INSERT OR ABORT make no changes to the return value of this
2065** routine when their insertion fails.  ^(When INSERT OR REPLACE
2066** encounters a constraint violation, it does not fail.  The
2067** INSERT continues to completion after deleting rows that caused
2068** the constraint problem so INSERT OR REPLACE will always change
2069** the return value of this interface.)^
2071** ^For the purposes of this routine, an [INSERT] is considered to
2072** be successful even if it is subsequently rolled back.
2074** This function is accessible to SQL statements via the
2075** [last_insert_rowid() SQL function].
2077** If a separate thread performs a new [INSERT] on the same
2078** database connection while the [sqlite3_last_insert_rowid()]
2079** function is running and thus changes the last insert [rowid],
2080** then the value returned by [sqlite3_last_insert_rowid()] is
2081** unpredictable and might not equal either the old or the new
2082** last insert [rowid].
2084SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
2087** CAPI3REF: Count The Number Of Rows Modified
2089** ^This function returns the number of rows modified, inserted or
2090** deleted by the most recently completed INSERT, UPDATE or DELETE
2091** statement on the database connection specified by the only parameter.
2092** ^Executing any other type of SQL statement does not modify the value
2093** returned by this function.
2095** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
2096** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
2097** [foreign key actions] or [REPLACE] constraint resolution are not counted.
2099** Changes to a view that are intercepted by
2100** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
2101** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
2102** DELETE statement run on a view is always zero. Only changes made to real
2103** tables are counted.
2105** Things are more complicated if the sqlite3_changes() function is
2106** executed while a trigger program is running. This may happen if the
2107** program uses the [changes() SQL function], or if some other callback
2108** function invokes sqlite3_changes() directly. Essentially:
2110** <ul>
2111**   <li> ^(Before entering a trigger program the value returned by
2112**        sqlite3_changes() function is saved. After the trigger program
2113**        has finished, the original value is restored.)^
2115**   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
2116**        statement sets the value returned by sqlite3_changes()
2117**        upon completion as normal. Of course, this value will not include
2118**        any changes performed by sub-triggers, as the sqlite3_changes()
2119**        value will be saved and restored after each sub-trigger has run.)^
2120** </ul>
2122** ^This means that if the changes() SQL function (or similar) is used
2123** by the first INSERT, UPDATE or DELETE statement within a trigger, it
2124** returns the value as set when the calling statement began executing.
2125** ^If it is used by the second or subsequent such statement within a trigger
2126** program, the value returned reflects the number of rows modified by the
2127** previous INSERT, UPDATE or DELETE statement within the same trigger.
2129** See also the [sqlite3_total_changes()] interface, the
2130** [count_changes pragma], and the [changes() SQL function].
2132** If a separate thread makes changes on the same database connection
2133** while [sqlite3_changes()] is running then the value returned
2134** is unpredictable and not meaningful.
2136SQLITE_API int sqlite3_changes(sqlite3*);
2139** CAPI3REF: Total Number Of Rows Modified
2141** ^This function returns the total number of rows inserted, modified or
2142** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2143** since the database connection was opened, including those executed as
2144** part of trigger programs. ^Executing any other type of SQL statement
2145** does not affect the value returned by sqlite3_total_changes().
2147** ^Changes made as part of [foreign key actions] are included in the
2148** count, but those made as part of REPLACE constraint resolution are
2149** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2150** are not counted.
2152** See also the [sqlite3_changes()] interface, the
2153** [count_changes pragma], and the [total_changes() SQL function].
2155** If a separate thread makes changes on the same database connection
2156** while [sqlite3_total_changes()] is running then the value
2157** returned is unpredictable and not meaningful.
2159SQLITE_API int sqlite3_total_changes(sqlite3*);
2162** CAPI3REF: Interrupt A Long-Running Query
2164** ^This function causes any pending database operation to abort and
2165** return at its earliest opportunity. This routine is typically
2166** called in response to a user action such as pressing "Cancel"
2167** or Ctrl-C where the user wants a long query operation to halt
2168** immediately.
2170** ^It is safe to call this routine from a thread different from the
2171** thread that is currently running the database operation.  But it
2172** is not safe to call this routine with a [database connection] that
2173** is closed or might close before sqlite3_interrupt() returns.
2175** ^If an SQL operation is very nearly finished at the time when
2176** sqlite3_interrupt() is called, then it might not have an opportunity
2177** to be interrupted and might continue to completion.
2179** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2180** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2181** that is inside an explicit transaction, then the entire transaction
2182** will be rolled back automatically.
2184** ^The sqlite3_interrupt(D) call is in effect until all currently running
2185** SQL statements on [database connection] D complete.  ^Any new SQL statements
2186** that are started after the sqlite3_interrupt() call and before the
2187** running statements reaches zero are interrupted as if they had been
2188** running prior to the sqlite3_interrupt() call.  ^New SQL statements
2189** that are started after the running statement count reaches zero are
2190** not effected by the sqlite3_interrupt().
2191** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2192** SQL statements is a no-op and has no effect on SQL statements
2193** that are started after the sqlite3_interrupt() call returns.
2195** If the database connection closes while [sqlite3_interrupt()]
2196** is running then bad things will likely happen.
2198SQLITE_API void sqlite3_interrupt(sqlite3*);
2201** CAPI3REF: Determine If An SQL Statement Is Complete
2203** These routines are useful during command-line input to determine if the
2204** currently entered text seems to form a complete SQL statement or
2205** if additional input is needed before sending the text into
2206** SQLite for parsing.  ^These routines return 1 if the input string
2207** appears to be a complete SQL statement.  ^A statement is judged to be
2208** complete if it ends with a semicolon token and is not a prefix of a
2209** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
2210** string literals or quoted identifier names or comments are not
2211** independent tokens (they are part of the token in which they are
2212** embedded) and thus do not count as a statement terminator.  ^Whitespace
2213** and comments that follow the final semicolon are ignored.
2215** ^These routines return 0 if the statement is incomplete.  ^If a
2216** memory allocation fails, then SQLITE_NOMEM is returned.
2218** ^These routines do not parse the SQL statements thus
2219** will not detect syntactically incorrect SQL.
2221** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2222** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2223** automatically by sqlite3_complete16().  If that initialization fails,
2224** then the return value from sqlite3_complete16() will be non-zero
2225** regardless of whether or not the input SQL is complete.)^
2227** The input to [sqlite3_complete()] must be a zero-terminated
2228** UTF-8 string.
2230** The input to [sqlite3_complete16()] must be a zero-terminated
2231** UTF-16 string in native byte order.
2233SQLITE_API int sqlite3_complete(const char *sql);
2234SQLITE_API int sqlite3_complete16(const void *sql);
2237** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2238** KEYWORDS: {busy-handler callback} {busy handler}
2240** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2241** that might be invoked with argument P whenever
2242** an attempt is made to access a database table associated with
2243** [database connection] D when another thread
2244** or process has the table locked.
2245** The sqlite3_busy_handler() interface is used to implement
2246** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2248** ^If the busy callback is NULL, then [SQLITE_BUSY]
2249** is returned immediately upon encountering the lock.  ^If the busy callback
2250** is not NULL, then the callback might be invoked with two arguments.
2252** ^The first argument to the busy handler is a copy of the void* pointer which
2253** is the third argument to sqlite3_busy_handler().  ^The second argument to
2254** the busy handler callback is the number of times that the busy handler has
2255** been invoked previously for the same locking event.  ^If the
2256** busy callback returns 0, then no additional attempts are made to
2257** access the database and [SQLITE_BUSY] is returned
2258** to the application.
2259** ^If the callback returns non-zero, then another attempt
2260** is made to access the database and the cycle repeats.
2262** The presence of a busy handler does not guarantee that it will be invoked
2263** when there is lock contention. ^If SQLite determines that invoking the busy
2264** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2265** to the application instead of invoking the
2266** busy handler.
2267** Consider a scenario where one process is holding a read lock that
2268** it is trying to promote to a reserved lock and
2269** a second process is holding a reserved lock that it is trying
2270** to promote to an exclusive lock.  The first process cannot proceed
2271** because it is blocked by the second and the second process cannot
2272** proceed because it is blocked by the first.  If both processes
2273** invoke the busy handlers, neither will make any progress.  Therefore,
2274** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2275** will induce the first process to release its read lock and allow
2276** the second process to proceed.
2278** ^The default busy callback is NULL.
2280** ^(There can only be a single busy handler defined for each
2281** [database connection].  Setting a new busy handler clears any
2282** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
2283** or evaluating [PRAGMA busy_timeout=N] will change the
2284** busy handler and thus clear any previously set busy handler.
2286** The busy callback should not take any actions which modify the
2287** database connection that invoked the busy handler.  In other words,
2288** the busy handler is not reentrant.  Any such actions
2289** result in undefined behavior.
2291** A busy handler must not close the database connection
2292** or [prepared statement] that invoked the busy handler.
2294SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
2297** CAPI3REF: Set A Busy Timeout
2299** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2300** for a specified amount of time when a table is locked.  ^The handler
2301** will sleep multiple times until at least "ms" milliseconds of sleeping
2302** have accumulated.  ^After at least "ms" milliseconds of sleeping,
2303** the handler returns 0 which causes [sqlite3_step()] to return
2304** [SQLITE_BUSY].
2306** ^Calling this routine with an argument less than or equal to zero
2307** turns off all busy handlers.
2309** ^(There can only be a single busy handler for a particular
2310** [database connection] at any given moment.  If another busy handler
2311** was defined  (using [sqlite3_busy_handler()]) prior to calling
2312** this routine, that other busy handler is cleared.)^
2314** See also:  [PRAGMA busy_timeout]
2316SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2319** CAPI3REF: Convenience Routines For Running Queries
2321** This is a legacy interface that is preserved for backwards compatibility.
2322** Use of this interface is not recommended.
2324** Definition: A <b>result table</b> is memory data structure created by the
2325** [sqlite3_get_table()] interface.  A result table records the
2326** complete query results from one or more queries.
2328** The table conceptually has a number of rows and columns.  But
2329** these numbers are not part of the result table itself.  These
2330** numbers are obtained separately.  Let N be the number of rows
2331** and M be the number of columns.
2333** A result table is an array of pointers to zero-terminated UTF-8 strings.
2334** There are (N+1)*M elements in the array.  The first M pointers point
2335** to zero-terminated strings that  contain the names of the columns.
2336** The remaining entries all point to query results.  NULL values result
2337** in NULL pointers.  All other values are in their UTF-8 zero-terminated
2338** string representation as returned by [sqlite3_column_text()].
2340** A result table might consist of one or more memory allocations.
2341** It is not safe to pass a result table directly to [sqlite3_free()].
2342** A result table should be deallocated using [sqlite3_free_table()].
2344** ^(As an example of the result table format, suppose a query result
2345** is as follows:
2347** <blockquote><pre>
2348**        Name        | Age
2349**        -----------------------
2350**        Alice       | 43
2351**        Bob         | 28
2352**        Cindy       | 21
2353** </pre></blockquote>
2355** There are two column (M==2) and three rows (N==3).  Thus the
2356** result table has 8 entries.  Suppose the result table is stored
2357** in an array names azResult.  Then azResult holds this content:
2359** <blockquote><pre>
2360**        azResult&#91;0] = "Name";
2361**        azResult&#91;1] = "Age";
2362**        azResult&#91;2] = "Alice";
2363**        azResult&#91;3] = "43";
2364**        azResult&#91;4] = "Bob";
2365**        azResult&#91;5] = "28";
2366**        azResult&#91;6] = "Cindy";
2367**        azResult&#91;7] = "21";
2368** </pre></blockquote>)^
2370** ^The sqlite3_get_table() function evaluates one or more
2371** semicolon-separated SQL statements in the zero-terminated UTF-8
2372** string of its 2nd parameter and returns a result table to the
2373** pointer given in its 3rd parameter.
2375** After the application has finished with the result from sqlite3_get_table(),
2376** it must pass the result table pointer to sqlite3_free_table() in order to
2377** release the memory that was malloced.  Because of the way the
2378** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2379** function must not try to call [sqlite3_free()] directly.  Only
2380** [sqlite3_free_table()] is able to release the memory properly and safely.
2382** The sqlite3_get_table() interface is implemented as a wrapper around
2383** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
2384** to any internal data structures of SQLite.  It uses only the public
2385** interface defined here.  As a consequence, errors that occur in the
2386** wrapper layer outside of the internal [sqlite3_exec()] call are not
2387** reflected in subsequent calls to [sqlite3_errcode()] or
2388** [sqlite3_errmsg()].
2390SQLITE_API int sqlite3_get_table(
2391  sqlite3 *db,          /* An open database */
2392  const char *zSql,     /* SQL to be evaluated */
2393  char ***pazResult,    /* Results of the query */
2394  int *pnRow,           /* Number of result rows written here */
2395  int *pnColumn,        /* Number of result columns written here */
2396  char **pzErrmsg       /* Error msg written here */
2398SQLITE_API void sqlite3_free_table(char **result);
2401** CAPI3REF: Formatted String Printing Functions
2403** These routines are work-alikes of the "printf()" family of functions
2404** from the standard C library.
2406** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2407** results into memory obtained from [sqlite3_malloc()].
2408** The strings returned by these two routines should be
2409** released by [sqlite3_free()].  ^Both routines return a
2410** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2411** memory to hold the resulting string.
2413** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2414** the standard C library.  The result is written into the
2415** buffer supplied as the second parameter whose size is given by
2416** the first parameter. Note that the order of the
2417** first two parameters is reversed from snprintf().)^  This is an
2418** historical accident that cannot be fixed without breaking
2419** backwards compatibility.  ^(Note also that sqlite3_snprintf()
2420** returns a pointer to its buffer instead of the number of
2421** characters actually written into the buffer.)^  We admit that
2422** the number of characters written would be a more useful return
2423** value but we cannot change the implementation of sqlite3_snprintf()
2424** now without breaking compatibility.
2426** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2427** guarantees that the buffer is always zero-terminated.  ^The first
2428** parameter "n" is the total size of the buffer, including space for
2429** the zero terminator.  So the longest string that can be completely
2430** written will be n-1 characters.
2432** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2434** These routines all implement some additional formatting
2435** options that are useful for constructing SQL statements.
2436** All of the usual printf() formatting options apply.  In addition, there
2437** is are "%q", "%Q", and "%z" options.
2439** ^(The %q option works like %s in that it substitutes a nul-terminated
2440** string from the argument list.  But %q also doubles every '\'' character.
2441** %q is designed for use inside a string literal.)^  By doubling each '\''
2442** character it escapes that character and allows it to be inserted into
2443** the string.
2445** For example, assume the string variable zText contains text as follows:
2447** <blockquote><pre>
2448**  char *zText = "It's a happy day!";
2449** </pre></blockquote>
2451** One can use this text in an SQL statement as follows:
2453** <blockquote><pre>
2454**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2455**  sqlite3_exec(db, zSQL, 0, 0, 0);
2456**  sqlite3_free(zSQL);
2457** </pre></blockquote>
2459** Because the %q format string is used, the '\'' character in zText
2460** is escaped and the SQL generated is as follows:
2462** <blockquote><pre>
2463**  INSERT INTO table1 VALUES('It''s a happy day!')
2464** </pre></blockquote>
2466** This is correct.  Had we used %s instead of %q, the generated SQL
2467** would have looked like this:
2469** <blockquote><pre>
2470**  INSERT INTO table1 VALUES('It's a happy day!');
2471** </pre></blockquote>
2473** This second example is an SQL syntax error.  As a general rule you should
2474** always use %q instead of %s when inserting text into a string literal.
2476** ^(The %Q option works like %q except it also adds single quotes around
2477** the outside of the total string.  Additionally, if the parameter in the
2478** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2479** single quotes).)^  So, for example, one could say:
2481** <blockquote><pre>
2482**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2483**  sqlite3_exec(db, zSQL, 0, 0, 0);
2484**  sqlite3_free(zSQL);
2485** </pre></blockquote>
2487** The code above will render a correct SQL statement in the zSQL
2488** variable even if the zText variable is a NULL pointer.
2490** ^(The "%z" formatting option works like "%s" but with the
2491** addition that after the string has been read and copied into
2492** the result, [sqlite3_free()] is called on the input string.)^
2494SQLITE_API char *sqlite3_mprintf(const char*,...);
2495SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2496SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2497SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2500** CAPI3REF: Memory Allocation Subsystem
2502** The SQLite core uses these three routines for all of its own
2503** internal memory allocation needs. "Core" in the previous sentence
2504** does not include operating-system specific VFS implementation.  The
2505** Windows VFS uses native malloc() and free() for some operations.
2507** ^The sqlite3_malloc() routine returns a pointer to a block
2508** of memory at least N bytes in length, where N is the parameter.
2509** ^If sqlite3_malloc() is unable to obtain sufficient free
2510** memory, it returns a NULL pointer.  ^If the parameter N to
2511** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2512** a NULL pointer.
2514** ^The sqlite3_malloc64(N) routine works just like
2515** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2516** of a signed 32-bit integer.
2518** ^Calling sqlite3_free() with a pointer previously returned
2519** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2520** that it might be reused.  ^The sqlite3_free() routine is
2521** a no-op if is called with a NULL pointer.  Passing a NULL pointer
2522** to sqlite3_free() is harmless.  After being freed, memory
2523** should neither be read nor written.  Even reading previously freed
2524** memory might result in a segmentation fault or other severe error.
2525** Memory corruption, a segmentation fault, or other severe error
2526** might result if sqlite3_free() is called with a non-NULL pointer that
2527** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2529** ^The sqlite3_realloc(X,N) interface attempts to resize a
2530** prior memory allocation X to be at least N bytes.
2531** ^If the X parameter to sqlite3_realloc(X,N)
2532** is a NULL pointer then its behavior is identical to calling
2533** sqlite3_malloc(N).
2534** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2535** negative then the behavior is exactly the same as calling
2536** sqlite3_free(X).
2537** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2538** of at least N bytes in size or NULL if insufficient memory is available.
2539** ^If M is the size of the prior allocation, then min(N,M) bytes
2540** of the prior allocation are copied into the beginning of buffer returned
2541** by sqlite3_realloc(X,N) and the prior allocation is freed.
2542** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2543** prior allocation is not freed.
2545** ^The sqlite3_realloc64(X,N) interfaces works the same as
2546** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2547** of a 32-bit signed integer.
2549** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2550** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2551** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2552** ^The value returned by sqlite3_msize(X) might be larger than the number
2553** of bytes requested when X was allocated.  ^If X is a NULL pointer then
2554** sqlite3_msize(X) returns zero.  If X points to something that is not
2555** the beginning of memory allocation, or if it points to a formerly
2556** valid memory allocation that has now been freed, then the behavior
2557** of sqlite3_msize(X) is undefined and possibly harmful.
2559** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2560** sqlite3_malloc64(), and sqlite3_realloc64()
2561** is always aligned to at least an 8 byte boundary, or to a
2562** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2563** option is used.
2565** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2566** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2567** implementation of these routines to be omitted.  That capability
2568** is no longer provided.  Only built-in memory allocators can be used.
2570** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2571** the system malloc() and free() directly when converting
2572** filenames between the UTF-8 encoding used by SQLite
2573** and whatever filename encoding is used by the particular Windows
2574** installation.  Memory allocation errors were detected, but
2575** they were reported back as [SQLITE_CANTOPEN] or
2576** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2578** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2579** must be either NULL or else pointers obtained from a prior
2580** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2581** not yet been released.
2583** The application must not read or write any part of
2584** a block of memory after it has been released using
2585** [sqlite3_free()] or [sqlite3_realloc()].
2587SQLITE_API void *sqlite3_malloc(int);
2588SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
2589SQLITE_API void *sqlite3_realloc(void*, int);
2590SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
2591SQLITE_API void sqlite3_free(void*);
2592SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
2595** CAPI3REF: Memory Allocator Statistics
2597** SQLite provides these two interfaces for reporting on the status
2598** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2599** routines, which form the built-in memory allocation subsystem.
2601** ^The [sqlite3_memory_used()] routine returns the number of bytes
2602** of memory currently outstanding (malloced but not freed).
2603** ^The [sqlite3_memory_highwater()] routine returns the maximum
2604** value of [sqlite3_memory_used()] since the high-water mark
2605** was last reset.  ^The values returned by [sqlite3_memory_used()] and
2606** [sqlite3_memory_highwater()] include any overhead
2607** added by SQLite in its implementation of [sqlite3_malloc()],
2608** but not overhead added by the any underlying system library
2609** routines that [sqlite3_malloc()] may call.
2611** ^The memory high-water mark is reset to the current value of
2612** [sqlite3_memory_used()] if and only if the parameter to
2613** [sqlite3_memory_highwater()] is true.  ^The value returned
2614** by [sqlite3_memory_highwater(1)] is the high-water mark
2615** prior to the reset.
2617SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2618SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2621** CAPI3REF: Pseudo-Random Number Generator
2623** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2624** select random [ROWID | ROWIDs] when inserting new records into a table that
2625** already uses the largest possible [ROWID].  The PRNG is also used for
2626** the build-in random() and randomblob() SQL functions.  This interface allows
2627** applications to access the same PRNG for other purposes.
2629** ^A call to this routine stores N bytes of randomness into buffer P.
2630** ^The P parameter can be a NULL pointer.
2632** ^If this routine has not been previously called or if the previous
2633** call had N less than one or a NULL pointer for P, then the PRNG is
2634** seeded using randomness obtained from the xRandomness method of
2635** the default [sqlite3_vfs] object.
2636** ^If the previous call to this routine had an N of 1 or more and a
2637** non-NULL P then the pseudo-randomness is generated
2638** internally and without recourse to the [sqlite3_vfs] xRandomness
2639** method.
2641SQLITE_API void sqlite3_randomness(int N, void *P);
2644** CAPI3REF: Compile-Time Authorization Callbacks
2646** ^This routine registers an authorizer callback with a particular
2647** [database connection], supplied in the first argument.
2648** ^The authorizer callback is invoked as SQL statements are being compiled
2649** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2650** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  ^At various
2651** points during the compilation process, as logic is being created
2652** to perform various actions, the authorizer callback is invoked to
2653** see if those actions are allowed.  ^The authorizer callback should
2654** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2655** specific action but allow the SQL statement to continue to be
2656** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2657** rejected with an error.  ^If the authorizer callback returns
2658** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2659** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2660** the authorizer will fail with an error message.
2662** When the callback returns [SQLITE_OK], that means the operation
2663** requested is ok.  ^When the callback returns [SQLITE_DENY], the
2664** [sqlite3_prepare_v2()] or equivalent call that triggered the
2665** authorizer will fail with an error message explaining that
2666** access is denied.
2668** ^The first parameter to the authorizer callback is a copy of the third
2669** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2670** to the callback is an integer [SQLITE_COPY | action code] that specifies
2671** the particular action to be authorized. ^The third through sixth parameters
2672** to the callback are zero-terminated strings that contain additional
2673** details about the action to be authorized.
2675** ^If the action code is [SQLITE_READ]
2676** and the callback returns [SQLITE_IGNORE] then the
2677** [prepared statement] statement is constructed to substitute
2678** a NULL value in place of the table column that would have
2679** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
2680** return can be used to deny an untrusted user access to individual
2681** columns of a table.
2682** ^If the action code is [SQLITE_DELETE] and the callback returns
2683** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2684** [truncate optimization] is disabled and all rows are deleted individually.
2686** An authorizer is used when [sqlite3_prepare | preparing]
2687** SQL statements from an untrusted source, to ensure that the SQL statements
2688** do not try to access data they are not allowed to see, or that they do not
2689** try to execute malicious statements that damage the database.  For
2690** example, an application may allow a user to enter arbitrary
2691** SQL queries for evaluation by a database.  But the application does
2692** not want the user to be able to make arbitrary changes to the
2693** database.  An authorizer could then be put in place while the
2694** user-entered SQL is being [sqlite3_prepare | prepared] that
2695** disallows everything except [SELECT] statements.
2697** Applications that need to process SQL from untrusted sources
2698** might also consider lowering resource limits using [sqlite3_limit()]
2699** and limiting database size using the [max_page_count] [PRAGMA]
2700** in addition to using an authorizer.
2702** ^(Only a single authorizer can be in place on a database connection
2703** at a time.  Each call to sqlite3_set_authorizer overrides the
2704** previous call.)^  ^Disable the authorizer by installing a NULL callback.
2705** The authorizer is disabled by default.
2707** The authorizer callback must not do anything that will modify
2708** the database connection that invoked the authorizer callback.
2709** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2710** database connections for the meaning of "modify" in this paragraph.
2712** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2713** statement might be re-prepared during [sqlite3_step()] due to a
2714** schema change.  Hence, the application should ensure that the
2715** correct authorizer callback remains in place during the [sqlite3_step()].
2717** ^Note that the authorizer callback is invoked only during
2718** [sqlite3_prepare()] or its variants.  Authorization is not
2719** performed during statement evaluation in [sqlite3_step()], unless
2720** as stated in the previous paragraph, sqlite3_step() invokes
2721** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2723SQLITE_API int sqlite3_set_authorizer(
2724  sqlite3*,
2725  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2726  void *pUserData
2730** CAPI3REF: Authorizer Return Codes
2732** The [sqlite3_set_authorizer | authorizer callback function] must
2733** return either [SQLITE_OK] or one of these two constants in order
2734** to signal SQLite whether or not the action is permitted.  See the
2735** [sqlite3_set_authorizer | authorizer documentation] for additional
2736** information.
2738** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2739** returned from the [sqlite3_vtab_on_conflict()] interface.
2741#define SQLITE_DENY   1   /* Abort the SQL statement with an error */
2742#define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
2745** CAPI3REF: Authorizer Action Codes
2747** The [sqlite3_set_authorizer()] interface registers a callback function
2748** that is invoked to authorize certain SQL statement actions.  The
2749** second parameter to the callback is an integer code that specifies
2750** what action is being authorized.  These are the integer action codes that
2751** the authorizer callback may be passed.
2753** These action code values signify what kind of operation is to be
2754** authorized.  The 3rd and 4th parameters to the authorization
2755** callback function will be parameters or NULL depending on which of these
2756** codes is used as the second parameter.  ^(The 5th parameter to the
2757** authorizer callback is the name of the database ("main", "temp",
2758** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
2759** is the name of the inner-most trigger or view that is responsible for
2760** the access attempt or NULL if this access attempt is directly from
2761** top-level SQL code.
2763/******************************************* 3rd ************ 4th ***********/
2764#define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
2765#define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
2766#define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
2767#define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
2768#define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
2769#define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
2770#define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
2771#define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
2772#define SQLITE_DELETE                9   /* Table Name      NULL            */
2773#define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
2774#define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
2775#define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
2776#define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
2777#define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
2778#define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
2779#define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
2780#define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
2781#define SQLITE_INSERT               18   /* Table Name      NULL            */
2782#define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
2783#define SQLITE_READ                 20   /* Table Name      Column Name     */
2784#define SQLITE_SELECT               21   /* NULL            NULL            */
2785#define SQLITE_TRANSACTION          22   /* Operation       NULL            */
2786#define SQLITE_UPDATE               23   /* Table Name      Column Name     */
2787#define SQLITE_ATTACH               24   /* Filename        NULL            */
2788#define SQLITE_DETACH               25   /* Database Name   NULL            */
2789#define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
2790#define SQLITE_REINDEX              27   /* Index Name      NULL            */
2791#define SQLITE_ANALYZE              28   /* Table Name      NULL            */
2792#define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
2793#define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
2794#define SQLITE_FUNCTION             31   /* NULL            Function Name   */
2795#define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
2796#define SQLITE_COPY                  0   /* No longer used */
2797#define SQLITE_RECURSIVE            33   /* NULL            NULL            */
2800** CAPI3REF: Tracing And Profiling Functions
2802** These routines register callback functions that can be used for
2803** tracing and profiling the execution of SQL statements.
2805** ^The callback function registered by sqlite3_trace() is invoked at
2806** various times when an SQL statement is being run by [sqlite3_step()].
2807** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2808** SQL statement text as the statement first begins executing.
2809** ^(Additional sqlite3_trace() callbacks might occur
2810** as each triggered subprogram is entered.  The callbacks for triggers
2811** contain a UTF-8 SQL comment that identifies the trigger.)^
2813** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2814** the length of [bound parameter] expansion in the output of sqlite3_trace().
2816** ^The callback function registered by sqlite3_profile() is invoked
2817** as each SQL statement finishes.  ^The profile callback contains
2818** the original statement text and an estimate of wall-clock time
2819** of how long that statement took to run.  ^The profile callback
2820** time is in units of nanoseconds, however the current implementation
2821** is only capable of millisecond resolution so the six least significant
2822** digits in the time are meaningless.  Future versions of SQLite
2823** might provide greater resolution on the profiler callback.  The
2824** sqlite3_profile() function is considered experimental and is
2825** subject to change in future versions of SQLite.
2827SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2828SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
2829   void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2832** CAPI3REF: Query Progress Callbacks
2834** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2835** function X to be invoked periodically during long running calls to
2836** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2837** database connection D.  An example use for this
2838** interface is to keep a GUI updated during a large query.
2840** ^The parameter P is passed through as the only parameter to the
2841** callback function X.  ^The parameter N is the approximate number of
2842** [virtual machine instructions] that are evaluated between successive
2843** invocations of the callback X.  ^If N is less than one then the progress
2844** handler is disabled.
2846** ^Only a single progress handler may be defined at one time per
2847** [database connection]; setting a new progress handler cancels the
2848** old one.  ^Setting parameter X to NULL disables the progress handler.
2849** ^The progress handler is also disabled by setting N to a value less
2850** than 1.
2852** ^If the progress callback returns non-zero, the operation is
2853** interrupted.  This feature can be used to implement a
2854** "Cancel" button on a GUI progress dialog box.
2856** The progress handler callback must not do anything that will modify
2857** the database connection that invoked the progress handler.
2858** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2859** database connections for the meaning of "modify" in this paragraph.
2862SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2865** CAPI3REF: Opening A New Database Connection
2867** ^These routines open an SQLite database file as specified by the
2868** filename argument. ^The filename argument is interpreted as UTF-8 for
2869** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2870** order for sqlite3_open16(). ^(A [database connection] handle is usually
2871** returned in *ppDb, even if an error occurs.  The only exception is that
2872** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2873** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2874** object.)^ ^(If the database is opened (and/or created) successfully, then
2875** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
2876** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2877** an English language description of the error following a failure of any
2878** of the sqlite3_open() routines.
2880** ^The default encoding will be UTF-8 for databases created using
2881** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
2882** created using sqlite3_open16() will be UTF-16 in the native byte order.
2884** Whether or not an error occurs when it is opened, resources
2885** associated with the [database connection] handle should be released by
2886** passing it to [sqlite3_close()] when it is no longer required.
2888** The sqlite3_open_v2() interface works like sqlite3_open()
2889** except that it accepts two additional parameters for additional control
2890** over the new database connection.  ^(The flags parameter to
2891** sqlite3_open_v2() can take one of
2892** the following three values, optionally combined with the
2896** <dl>
2897** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2898** <dd>The database is opened in read-only mode.  If the database does not
2899** already exist, an error is returned.</dd>)^
2901** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2902** <dd>The database is opened for reading and writing if possible, or reading
2903** only if the file is write protected by the operating system.  In either
2904** case the database must already exist, otherwise an error is returned.</dd>)^
2907** <dd>The database is opened for reading and writing, and is created if
2908** it does not already exist. This is the behavior that is always used for
2909** sqlite3_open() and sqlite3_open16().</dd>)^
2910** </dl>
2912** If the 3rd parameter to sqlite3_open_v2() is not one of the
2913** combinations shown above optionally combined with other
2915** then the behavior is undefined.
2917** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2918** opens in the multi-thread [threading mode] as long as the single-thread
2919** mode has not been set at compile-time or start-time.  ^If the
2920** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2921** in the serialized [threading mode] unless single-thread was
2922** previously selected at compile-time or start-time.
2923** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2924** eligible to use [shared cache mode], regardless of whether or not shared
2925** cache is enabled using [sqlite3_enable_shared_cache()].  ^The
2926** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2927** participate in [shared cache mode] even if it is enabled.
2929** ^The fourth parameter to sqlite3_open_v2() is the name of the
2930** [sqlite3_vfs] object that defines the operating system interface that
2931** the new database connection should use.  ^If the fourth parameter is
2932** a NULL pointer then the default [sqlite3_vfs] object is used.
2934** ^If the filename is ":memory:", then a private, temporary in-memory database
2935** is created for the connection.  ^This in-memory database will vanish when
2936** the database connection is closed.  Future versions of SQLite might
2937** make use of additional special filenames that begin with the ":" character.
2938** It is recommended that when a database filename actually does begin with
2939** a ":" character you should prefix the filename with a pathname such as
2940** "./" to avoid ambiguity.
2942** ^If the filename is an empty string, then a private, temporary
2943** on-disk database will be created.  ^This private database will be
2944** automatically deleted as soon as the database connection is closed.
2946** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
2948** ^If [URI filename] interpretation is enabled, and the filename argument
2949** begins with "file:", then the filename is interpreted as a URI. ^URI
2950** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
2951** set in the fourth argument to sqlite3_open_v2(), or if it has
2952** been enabled globally using the [SQLITE_CONFIG_URI] option with the
2953** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
2954** As of SQLite version 3.7.7, URI filename interpretation is turned off
2955** by default, but future releases of SQLite might enable URI filename
2956** interpretation by default.  See "[URI filenames]" for additional
2957** information.
2959** URI filenames are parsed according to RFC 3986. ^If the URI contains an
2960** authority, then it must be either an empty string or the string
2961** "localhost". ^If the authority is not an empty string or "localhost", an
2962** error is returned to the caller. ^The fragment component of a URI, if
2963** present, is ignored.
2965** ^SQLite uses the path component of the URI as the name of the disk file
2966** which contains the database. ^If the path begins with a '/' character,
2967** then it is interpreted as an absolute path. ^If the path does not begin
2968** with a '/' (meaning that the authority section is omitted from the URI)
2969** then the path is interpreted as a relative path.
2970** ^(On windows, the first component of an absolute path
2971** is a drive specification (e.g. "C:").)^
2973** [[core URI query parameters]]
2974** The query component of a URI may contain parameters that are interpreted
2975** either by SQLite itself, or by a [VFS | custom VFS implementation].
2976** SQLite and its built-in [VFSes] interpret the
2977** following query parameters:
2979** <ul>
2980**   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
2981**     a VFS object that provides the operating system interface that should
2982**     be used to access the database file on disk. ^If this option is set to
2983**     an empty string the default VFS object is used. ^Specifying an unknown
2984**     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
2985**     present, then the VFS specified by the option takes precedence over
2986**     the value passed as the fourth parameter to sqlite3_open_v2().
2988**   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
2989**     "rwc", or "memory". Attempting to set it to any other value is
2990**     an error)^.
2991**     ^If "ro" is specified, then the database is opened for read-only
2992**     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
2993**     third argument to sqlite3_open_v2(). ^If the mode option is set to
2994**     "rw", then the database is opened for read-write (but not create)
2995**     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
2996**     been set. ^Value "rwc" is equivalent to setting both
2997**     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
2998**     set to "memory" then a pure [in-memory database] that never reads
2999**     or writes from disk is used. ^It is an error to specify a value for
3000**     the mode parameter that is less restrictive than that specified by
3001**     the flags passed in the third parameter to sqlite3_open_v2().
3003**   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
3004**     "private". ^Setting it to "shared" is equivalent to setting the
3005**     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
3006**     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
3007**     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
3008**     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
3009**     a URI filename, its value overrides any behavior requested by setting
3012**  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
3013**     [powersafe overwrite] property does or does not apply to the
3014**     storage media on which the database file resides.
3016**  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
3017**     which if set disables file locking in rollback journal modes.  This
3018**     is useful for accessing a database on a filesystem that does not
3019**     support locking.  Caution:  Database corruption might result if two
3020**     or more processes write to the same database and any one of those
3021**     processes uses nolock=1.
3023**  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
3024**     parameter that indicates that the database file is stored on
3025**     read-only media.  ^When immutable is set, SQLite assumes that the
3026**     database file cannot be changed, even by a process with higher
3027**     privilege, and so the database is opened read-only and all locking
3028**     and change detection is disabled.  Caution: Setting the immutable
3029**     property on a database file that does in fact change can result
3030**     in incorrect query results and/or [SQLITE_CORRUPT] errors.
3031**     See also: [SQLITE_IOCAP_IMMUTABLE].
3033** </ul>
3035** ^Specifying an unknown parameter in the query component of a URI is not an
3036** error.  Future versions of SQLite might understand additional query
3037** parameters.  See "[query parameters with special meaning to SQLite]" for
3038** additional information.
3040** [[URI filename examples]] <h3>URI filename examples</h3>
3042** <table border="1" align=center cellpadding=5>
3043** <tr><th> URI filenames <th> Results
3044** <tr><td> file:data.db <td>
3045**          Open the file "data.db" in the current directory.
3046** <tr><td> file:/home/fred/data.db<br>
3047**          file:///home/fred/data.db <br>
3048**          file://localhost/home/fred/data.db <br> <td>
3049**          Open the database file "/home/fred/data.db".
3050** <tr><td> file://darkstar/home/fred/data.db <td>
3051**          An error. "darkstar" is not a recognized authority.
3052** <tr><td style="white-space:nowrap">
3053**          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
3054**     <td> Windows only: Open the file "data.db" on fred's desktop on drive
3055**          C:. Note that the %20 escaping in this example is not strictly
3056**          necessary - space characters can be used literally
3057**          in URI filenames.
3058** <tr><td> file:data.db?mode=ro&cache=private <td>
3059**          Open file "data.db" in the current directory for read-only access.
3060**          Regardless of whether or not shared-cache mode is enabled by
3061**          default, use a private cache.
3062** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
3063**          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
3064**          that uses dot-files in place of posix advisory locking.
3065** <tr><td> file:data.db?mode=readonly <td>
3066**          An error. "readonly" is not a valid option for the "mode" parameter.
3067** </table>
3069** ^URI hexadecimal escape sequences (%HH) are supported within the path and
3070** query components of a URI. A hexadecimal escape sequence consists of a
3071** percent sign - "%" - followed by exactly two hexadecimal digits
3072** specifying an octet value. ^Before the path or query components of a
3073** URI filename are interpreted, they are encoded using UTF-8 and all
3074** hexadecimal escape sequences replaced by a single byte containing the
3075** corresponding octet. If this process generates an invalid UTF-8 encoding,
3076** the results are undefined.
3078** <b>Note to Windows users:</b>  The encoding used for the filename argument
3079** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
3080** codepage is currently defined.  Filenames containing international
3081** characters must be converted to UTF-8 prior to passing them into
3082** sqlite3_open() or sqlite3_open_v2().
3084** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
3085** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
3086** features that require the use of temporary files may fail.
3088** See also: [sqlite3_temp_directory]
3090SQLITE_API int sqlite3_open(
3091  const char *filename,   /* Database filename (UTF-8) */
3092  sqlite3 **ppDb          /* OUT: SQLite db handle */
3094SQLITE_API int sqlite3_open16(
3095  const void *filename,   /* Database filename (UTF-16) */
3096  sqlite3 **ppDb          /* OUT: SQLite db handle */
3098SQLITE_API int sqlite3_open_v2(
3099  const char *filename,   /* Database filename (UTF-8) */
3100  sqlite3 **ppDb,         /* OUT: SQLite db handle */
3101  int flags,              /* Flags */
3102  const char *zVfs        /* Name of VFS module to use */
3106** CAPI3REF: Obtain Values For URI Parameters
3108** These are utility routines, useful to VFS implementations, that check
3109** to see if a database file was a URI that contained a specific query
3110** parameter, and if so obtains the value of that query parameter.
3112** If F is the database filename pointer passed into the xOpen() method of
3113** a VFS implementation when the flags parameter to xOpen() has one or
3114** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
3115** P is the name of the query parameter, then
3116** sqlite3_uri_parameter(F,P) returns the value of the P
3117** parameter if it exists or a NULL pointer if P does not appear as a
3118** query parameter on F.  If P is a query parameter of F
3119** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3120** a pointer to an empty string.
3122** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3123** parameter and returns true (1) or false (0) according to the value
3124** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3125** value of query parameter P is one of "yes", "true", or "on" in any
3126** case or if the value begins with a non-zero number.  The
3127** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3128** query parameter P is one of "no", "false", or "off" in any case or
3129** if the value begins with a numeric zero.  If P is not a query
3130** parameter on F or if the value of P is does not match any of the
3131** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3133** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3134** 64-bit signed integer and returns that integer, or D if P does not
3135** exist.  If the value of P is something other than an integer, then
3136** zero is returned.
3138** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3139** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
3140** is not a database file pathname pointer that SQLite passed into the xOpen
3141** VFS method, then the behavior of this routine is undefined and probably
3142** undesirable.
3144SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3145SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3146SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3150** CAPI3REF: Error Codes And Messages
3152** ^The sqlite3_errcode() interface returns the numeric [result code] or
3153** [extended result code] for the most recent failed sqlite3_* API call
3154** associated with a [database connection]. If a prior API call failed
3155** but the most recent API call succeeded, the return value from
3156** sqlite3_errcode() is undefined.  ^The sqlite3_extended_errcode()
3157** interface is the same except that it always returns the
3158** [extended result code] even when extended result codes are
3159** disabled.
3161** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3162** text that describes the error, as either UTF-8 or UTF-16 respectively.
3163** ^(Memory to hold the error message string is managed internally.
3164** The application does not need to worry about freeing the result.
3165** However, the error string might be overwritten or deallocated by
3166** subsequent calls to other SQLite interface functions.)^
3168** ^The sqlite3_errstr() interface returns the English-language text
3169** that describes the [result code], as UTF-8.
3170** ^(Memory to hold the error message string is managed internally
3171** and must not be freed by the application)^.
3173** When the serialized [threading mode] is in use, it might be the
3174** case that a second error occurs on a separate thread in between
3175** the time of the first error and the call to these interfaces.
3176** When that happens, the second error will be reported since these
3177** interfaces always report the most recent result.  To avoid
3178** this, each thread can obtain exclusive use of the [database connection] D
3179** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3180** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3181** all calls to the interfaces listed here are completed.
3183** If an interface fails with SQLITE_MISUSE, that means the interface
3184** was invoked incorrectly by the application.  In that case, the
3185** error code and message may or may not be set.
3187SQLITE_API int sqlite3_errcode(sqlite3 *db);
3188SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
3189SQLITE_API const char *sqlite3_errmsg(sqlite3*);
3190SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
3191SQLITE_API const char *sqlite3_errstr(int);
3194** CAPI3REF: SQL Statement Object
3195** KEYWORDS: {prepared statement} {prepared statements}
3197** An instance of this object represents a single SQL statement.
3198** This object is variously known as a "prepared statement" or a
3199** "compiled SQL statement" or simply as a "statement".
3201** The life of a statement object goes something like this:
3203** <ol>
3204** <li> Create the object using [sqlite3_prepare_v2()] or a related
3205**      function.
3206** <li> Bind values to [host parameters] using the sqlite3_bind_*()
3207**      interfaces.
3208** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3209** <li> Reset the statement using [sqlite3_reset()] then go back
3210**      to step 2.  Do this zero or more times.
3211** <li> Destroy the object using [sqlite3_finalize()].
3212** </ol>
3214** Refer to documentation on individual methods above for additional
3215** information.
3217typedef struct sqlite3_stmt sqlite3_stmt;
3220** CAPI3REF: Run-time Limits
3222** ^(This interface allows the size of various constructs to be limited
3223** on a connection by connection basis.  The first parameter is the
3224** [database connection] whose limit is to be set or queried.  The
3225** second parameter is one of the [limit categories] that define a
3226** class of constructs to be size limited.  The third parameter is the
3227** new limit for that construct.)^
3229** ^If the new limit is a negative number, the limit is unchanged.
3230** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3231** [limits | hard upper bound]
3232** set at compile-time by a C preprocessor macro called
3233** [limits | SQLITE_MAX_<i>NAME</i>].
3234** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3235** ^Attempts to increase a limit above its hard upper bound are
3236** silently truncated to the hard upper bound.
3238** ^Regardless of whether or not the limit was changed, the
3239** [sqlite3_limit()] interface returns the prior value of the limit.
3240** ^Hence, to find the current value of a limit without changing it,
3241** simply invoke this interface with the third parameter set to -1.
3243** Run-time limits are intended for use in applications that manage
3244** both their own internal database and also databases that are controlled
3245** by untrusted external sources.  An example application might be a
3246** web browser that has its own databases for storing history and
3247** separate databases controlled by JavaScript applications downloaded
3248** off the Internet.  The internal databases can be given the
3249** large, default limits.  Databases managed by external sources can
3250** be given much smaller limits designed to prevent a denial of service
3251** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
3252** interface to further control untrusted SQL.  The size of the database
3253** created by an untrusted script can be contained using the
3254** [max_page_count] [PRAGMA].
3256** New run-time limit categories may be added in future releases.
3258SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
3261** CAPI3REF: Run-Time Limit Categories
3262** KEYWORDS: {limit category} {*limit categories}
3264** These constants define various performance limits
3265** that can be lowered at run-time using [sqlite3_limit()].
3266** The synopsis of the meanings of the various limits is shown below.
3267** Additional information is available at [limits | Limits in SQLite].
3269** <dl>
3271** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3274** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3277** <dd>The maximum number of columns in a table definition or in the
3278** result set of a [SELECT] or the maximum number of columns in an index
3279** or in an ORDER BY or GROUP BY clause.</dd>)^
3282** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3285** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3288** <dd>The maximum number of instructions in a virtual machine program
3289** used to implement an SQL statement.  This limit is not currently
3290** enforced, though that might be added in some future release of
3291** SQLite.</dd>)^
3294** <dd>The maximum number of arguments on a function.</dd>)^
3297** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3301** <dd>The maximum length of the pattern argument to the [LIKE] or
3302** [GLOB] operators.</dd>)^
3306** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3309** <dd>The maximum depth of recursion for triggers.</dd>)^
3312** <dd>The maximum number of auxiliary worker threads that a single
3313** [prepared statement] may start.</dd>)^
3314** </dl>
3316#define SQLITE_LIMIT_LENGTH                    0
3317#define SQLITE_LIMIT_SQL_LENGTH                1
3318#define SQLITE_LIMIT_COLUMN                    2
3319#define SQLITE_LIMIT_EXPR_DEPTH                3
3320#define SQLITE_LIMIT_COMPOUND_SELECT           4
3321#define SQLITE_LIMIT_VDBE_OP                   5
3322#define SQLITE_LIMIT_FUNCTION_ARG              6
3323#define SQLITE_LIMIT_ATTACHED                  7
3325#define SQLITE_LIMIT_VARIABLE_NUMBER           9
3326#define SQLITE_LIMIT_TRIGGER_DEPTH            10
3327#define SQLITE_LIMIT_WORKER_THREADS           11
3330** CAPI3REF: Compiling An SQL Statement
3331** KEYWORDS: {SQL statement compiler}
3333** To execute an SQL query, it must first be compiled into a byte-code
3334** program using one of these routines.
3336** The first argument, "db", is a [database connection] obtained from a
3337** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3338** [sqlite3_open16()].  The database connection must not have been closed.
3340** The second argument, "zSql", is the statement to be compiled, encoded
3341** as either UTF-8 or UTF-16.  The sqlite3_prepare() and sqlite3_prepare_v2()
3342** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
3343** use UTF-16.
3345** ^If the nByte argument is less than zero, then zSql is read up to the
3346** first zero terminator. ^If nByte is non-negative, then it is the maximum
3347** number of  bytes read from zSql.  ^When nByte is non-negative, the
3348** zSql string ends at either the first '\000' or '\u0000' character or
3349** the nByte-th byte, whichever comes first. If the caller knows
3350** that the supplied string is nul-terminated, then there is a small
3351** performance advantage to be gained by passing an nByte parameter that
3352** is equal to the number of bytes in the input string <i>including</i>
3353** the nul-terminator bytes as this saves SQLite from having to
3354** make a copy of the input string.
3356** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3357** past the end of the first SQL statement in zSql.  These routines only
3358** compile the first statement in zSql, so *pzTail is left pointing to
3359** what remains uncompiled.
3361** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3362** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
3363** to NULL.  ^If the input text contains no SQL (if the input is an empty
3364** string or a comment) then *ppStmt is set to NULL.
3365** The calling procedure is responsible for deleting the compiled
3366** SQL statement using [sqlite3_finalize()] after it has finished with it.
3367** ppStmt may not be NULL.
3369** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3370** otherwise an [error code] is returned.
3372** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
3373** recommended for all new programs. The two older interfaces are retained
3374** for backwards compatibility, but their use is discouraged.
3375** ^In the "v2" interfaces, the prepared statement
3376** that is returned (the [sqlite3_stmt] object) contains a copy of the
3377** original SQL text. This causes the [sqlite3_step()] interface to
3378** behave differently in three ways:
3380** <ol>
3381** <li>
3382** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3383** always used to do, [sqlite3_step()] will automatically recompile the SQL
3384** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3385** retries will occur before sqlite3_step() gives up and returns an error.
3386** </li>
3388** <li>
3389** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3390** [error codes] or [extended error codes].  ^The legacy behavior was that
3391** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3392** and the application would have to make a second call to [sqlite3_reset()]
3393** in order to find the underlying cause of the problem. With the "v2" prepare
3394** interfaces, the underlying reason for the error is returned immediately.
3395** </li>
3397** <li>
3398** ^If the specific value bound to [parameter | host parameter] in the
3399** WHERE clause might influence the choice of query plan for a statement,
3400** then the statement will be automatically recompiled, as if there had been
3401** a schema change, on the first  [sqlite3_step()] call following any change
3402** to the [sqlite3_bind_text | bindings] of that [parameter].
3403** ^The specific value of WHERE-clause [parameter] might influence the
3404** choice of query plan if the parameter is the left-hand side of a [LIKE]
3405** or [GLOB] operator or if the parameter is compared to an indexed column
3406** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3407** </li>
3408** </ol>
3410SQLITE_API int sqlite3_prepare(
3411  sqlite3 *db,            /* Database handle */
3412  const char *zSql,       /* SQL statement, UTF-8 encoded */
3413  int nByte,              /* Maximum length of zSql in bytes. */
3414  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3415  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
3417SQLITE_API int sqlite3_prepare_v2(
3418  sqlite3 *db,            /* Database handle */
3419  const char *zSql,       /* SQL statement, UTF-8 encoded */
3420  int nByte,              /* Maximum length of zSql in bytes. */
3421  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3422  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
3424SQLITE_API int sqlite3_prepare16(
3425  sqlite3 *db,            /* Database handle */
3426  const void *zSql,       /* SQL statement, UTF-16 encoded */
3427  int nByte,              /* Maximum length of zSql in bytes. */
3428  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3429  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
3431SQLITE_API int sqlite3_prepare16_v2(
3432  sqlite3 *db,            /* Database handle */
3433  const void *zSql,       /* SQL statement, UTF-16 encoded */
3434  int nByte,              /* Maximum length of zSql in bytes. */
3435  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3436  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
3440** CAPI3REF: Retrieving Statement SQL
3442** ^This interface can be used to retrieve a saved copy of the original
3443** SQL text used to create a [prepared statement] if that statement was
3444** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
3446SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
3449** CAPI3REF: Determine If An SQL Statement Writes The Database
3451** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3452** and only if the [prepared statement] X makes no direct changes to
3453** the content of the database file.
3455** Note that [application-defined SQL functions] or
3456** [virtual tables] might change the database indirectly as a side effect.
3457** ^(For example, if an application defines a function "eval()" that
3458** calls [sqlite3_exec()], then the following SQL statement would
3459** change the database file through side-effects:
3461** <blockquote><pre>
3462**    SELECT eval('DELETE FROM t1') FROM t2;
3463** </pre></blockquote>
3465** But because the [SELECT] statement does not change the database file
3466** directly, sqlite3_stmt_readonly() would still return true.)^
3468** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3469** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3470** since the statements themselves do not actually modify the database but
3471** rather they control the timing of when other statements modify the
3472** database.  ^The [ATTACH] and [DETACH] statements also cause
3473** sqlite3_stmt_readonly() to return true since, while those statements
3474** change the configuration of a database connection, they do not make
3475** changes to the content of the database files on disk.
3477SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3480** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3482** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3483** [prepared statement] S has been stepped at least once using
3484** [sqlite3_step(S)] but has not run to completion and/or has not
3485** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
3486** interface returns false if S is a NULL pointer.  If S is not a
3487** NULL pointer and is not a pointer to a valid [prepared statement]
3488** object, then the behavior is undefined and probably undesirable.
3490** This interface can be used in combination [sqlite3_next_stmt()]
3491** to locate all prepared statements associated with a database
3492** connection that are in need of being reset.  This can be used,
3493** for example, in diagnostic routines to search for prepared
3494** statements that are holding a transaction open.
3496SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
3499** CAPI3REF: Dynamically Typed Value Object
3500** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3502** SQLite uses the sqlite3_value object to represent all values
3503** that can be stored in a database table. SQLite uses dynamic typing
3504** for the values it stores.  ^Values stored in sqlite3_value objects
3505** can be integers, floating point values, strings, BLOBs, or NULL.
3507** An sqlite3_value object may be either "protected" or "unprotected".
3508** Some interfaces require a protected sqlite3_value.  Other interfaces
3509** will accept either a protected or an unprotected sqlite3_value.
3510** Every interface that accepts sqlite3_value arguments specifies
3511** whether or not it requires a protected sqlite3_value.
3513** The terms "protected" and "unprotected" refer to whether or not
3514** a mutex is held.  An internal mutex is held for a protected
3515** sqlite3_value object but no mutex is held for an unprotected
3516** sqlite3_value object.  If SQLite is compiled to be single-threaded
3517** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3518** or if SQLite is run in one of reduced mutex modes
3520** then there is no distinction between protected and unprotected
3521** sqlite3_value objects and they can be used interchangeably.  However,
3522** for maximum code portability it is recommended that applications
3523** still make the distinction between protected and unprotected
3524** sqlite3_value objects even when not strictly required.
3526** ^The sqlite3_value objects that are passed as parameters into the
3527** implementation of [application-defined SQL functions] are protected.
3528** ^The sqlite3_value object returned by
3529** [sqlite3_column_value()] is unprotected.
3530** Unprotected sqlite3_value objects may only be used with
3531** [sqlite3_result_value()] and [sqlite3_bind_value()].
3532** The [sqlite3_value_blob | sqlite3_value_type()] family of
3533** interfaces require protected sqlite3_value objects.
3535typedef struct Mem sqlite3_value;
3538** CAPI3REF: SQL Function Context Object
3540** The context in which an SQL function executes is stored in an
3541** sqlite3_context object.  ^A pointer to an sqlite3_context object
3542** is always first parameter to [application-defined SQL functions].
3543** The application-defined SQL function implementation will pass this
3544** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3545** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3546** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3547** and/or [sqlite3_set_auxdata()].
3549typedef struct sqlite3_context sqlite3_context;
3552** CAPI3REF: Binding Values To Prepared Statements
3553** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3554** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3556** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3557** literals may be replaced by a [parameter] that matches one of following
3558** templates:
3560** <ul>
3561** <li>  ?
3562** <li>  ?NNN
3563** <li>  :VVV
3564** <li>  @VVV
3565** <li>  $VVV
3566** </ul>
3568** In the templates above, NNN represents an integer literal,
3569** and VVV represents an alphanumeric identifier.)^  ^The values of these
3570** parameters (also called "host parameter names" or "SQL parameters")
3571** can be set using the sqlite3_bind_*() routines defined here.
3573** ^The first argument to the sqlite3_bind_*() routines is always
3574** a pointer to the [sqlite3_stmt] object returned from
3575** [sqlite3_prepare_v2()] or its variants.
3577** ^The second argument is the index of the SQL parameter to be set.
3578** ^The leftmost SQL parameter has an index of 1.  ^When the same named
3579** SQL parameter is used more than once, second and subsequent
3580** occurrences have the same index as the first occurrence.
3581** ^The index for named parameters can be looked up using the
3582** [sqlite3_bind_parameter_index()] API if desired.  ^The index
3583** for "?NNN" parameters is the value of NNN.
3584** ^The NNN value must be between 1 and the [sqlite3_limit()]
3585** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3587** ^The third argument is the value to bind to the parameter.
3588** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3589** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3590** is ignored and the end result is the same as sqlite3_bind_null().
3592** ^(In those routines that have a fourth argument, its value is the
3593** number of bytes in the parameter.  To be clear: the value is the
3594** number of <u>bytes</u> in the value, not the number of characters.)^
3595** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3596** is negative, then the length of the string is
3597** the number of bytes up to the first zero terminator.
3598** If the fourth parameter to sqlite3_bind_blob() is negative, then
3599** the behavior is undefined.
3600** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3601** or sqlite3_bind_text16() or sqlite3_bind_text64() then
3602** that parameter must be the byte offset
3603** where the NUL terminator would occur assuming the string were NUL
3604** terminated.  If any NUL characters occur at byte offsets less than
3605** the value of the fourth parameter then the resulting string value will
3606** contain embedded NULs.  The result of expressions involving strings
3607** with embedded NULs is undefined.
3609** ^The fifth argument to the BLOB and string binding interfaces
3610** is a destructor used to dispose of the BLOB or
3611** string after SQLite has finished with it.  ^The destructor is called
3612** to dispose of the BLOB or string even if the call to bind API fails.
3613** ^If the fifth argument is
3614** the special value [SQLITE_STATIC], then SQLite assumes that the
3615** information is in static, unmanaged space and does not need to be freed.
3616** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3617** SQLite makes its own private copy of the data immediately, before
3618** the sqlite3_bind_*() routine returns.
3620** ^The sixth argument to sqlite3_bind_text64() must be one of
3622** to specify the encoding of the text in the third parameter.  If
3623** the sixth argument to sqlite3_bind_text64() is not one of the
3624** allowed values shown above, or if the text encoding is different
3625** from the encoding specified by the sixth parameter, then the behavior
3626** is undefined.
3628** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3629** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
3630** (just an integer to hold its size) while it is being processed.
3631** Zeroblobs are intended to serve as placeholders for BLOBs whose
3632** content is later written using
3633** [sqlite3_blob_open | incremental BLOB I/O] routines.
3634** ^A negative value for the zeroblob results in a zero-length BLOB.
3636** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3637** for the [prepared statement] or with a prepared statement for which
3638** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3639** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
3640** routine is passed a [prepared statement] that has been finalized, the
3641** result is undefined and probably harmful.
3643** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3644** ^Unbound parameters are interpreted as NULL.
3646** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3647** [error code] if anything goes wrong.
3648** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
3649** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
3651** ^[SQLITE_RANGE] is returned if the parameter
3652** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
3654** See also: [sqlite3_bind_parameter_count()],
3655** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3657SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3658SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
3659                        void(*)(void*));
3660SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
3661SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
3662SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3663SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
3664SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
3665SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3666SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
3667                         void(*)(void*), unsigned char encoding);
3668SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3669SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3672** CAPI3REF: Number Of SQL Parameters
3674** ^This routine can be used to find the number of [SQL parameters]
3675** in a [prepared statement].  SQL parameters are tokens of the
3676** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3677** placeholders for values that are [sqlite3_bind_blob | bound]
3678** to the parameters at a later time.
3680** ^(This routine actually returns the index of the largest (rightmost)
3681** parameter. For all forms except ?NNN, this will correspond to the
3682** number of unique parameters.  If parameters of the ?NNN form are used,
3683** there may be gaps in the list.)^
3685** See also: [sqlite3_bind_blob|sqlite3_bind()],
3686** [sqlite3_bind_parameter_name()], and
3687** [sqlite3_bind_parameter_index()].
3689SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
3692** CAPI3REF: Name Of A Host Parameter
3694** ^The sqlite3_bind_parameter_name(P,N) interface returns
3695** the name of the N-th [SQL parameter] in the [prepared statement] P.
3696** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3697** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3698** respectively.
3699** In other words, the initial ":" or "$" or "@" or "?"
3700** is included as part of the name.)^
3701** ^Parameters of the form "?" without a following integer have no name
3702** and are referred to as "nameless" or "anonymous parameters".
3704** ^The first host parameter has an index of 1, not 0.
3706** ^If the value N is out of range or if the N-th parameter is
3707** nameless, then NULL is returned.  ^The returned string is
3708** always in UTF-8 encoding even if the named parameter was
3709** originally specified as UTF-16 in [sqlite3_prepare16()] or
3710** [sqlite3_prepare16_v2()].
3712** See also: [sqlite3_bind_blob|sqlite3_bind()],
3713** [sqlite3_bind_parameter_count()], and
3714** [sqlite3_bind_parameter_index()].
3716SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
3719** CAPI3REF: Index Of A Parameter With A Given Name
3721** ^Return the index of an SQL parameter given its name.  ^The
3722** index value returned is suitable for use as the second
3723** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
3724** is returned if no matching parameter is found.  ^The parameter
3725** name must be given in UTF-8 even if the original statement
3726** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3728** See also: [sqlite3_bind_blob|sqlite3_bind()],
3729** [sqlite3_bind_parameter_count()], and
3730** [sqlite3_bind_parameter_index()].
3732SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
3735** CAPI3REF: Reset All Bindings On A Prepared Statement
3737** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3738** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3739** ^Use this routine to reset all host parameters to NULL.
3741SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
3744** CAPI3REF: Number Of Columns In A Result Set
3746** ^Return the number of columns in the result set returned by the
3747** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3748** statement that does not return data (for example an [UPDATE]).
3750** See also: [sqlite3_data_count()]
3752SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
3755** CAPI3REF: Column Names In A Result Set
3757** ^These routines return the name assigned to a particular column
3758** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
3759** interface returns a pointer to a zero-terminated UTF-8 string
3760** and sqlite3_column_name16() returns a pointer to a zero-terminated
3761** UTF-16 string.  ^The first parameter is the [prepared statement]
3762** that implements the [SELECT] statement. ^The second parameter is the
3763** column number.  ^The leftmost column is number 0.
3765** ^The returned string pointer is valid until either the [prepared statement]
3766** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3767** reprepared by the first call to [sqlite3_step()] for a particular run
3768** or until the next call to
3769** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3771** ^If sqlite3_malloc() fails during the processing of either routine
3772** (for example during a conversion from UTF-8 to UTF-16) then a
3773** NULL pointer is returned.
3775** ^The name of a result column is the value of the "AS" clause for
3776** that column, if there is an AS clause.  If there is no AS clause
3777** then the name of the column is unspecified and may change from
3778** one release of SQLite to the next.
3780SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
3781SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
3784** CAPI3REF: Source Of Data In A Query Result
3786** ^These routines provide a means to determine the database, table, and
3787** table column that is the origin of a particular result column in
3788** [SELECT] statement.
3789** ^The name of the database or table or column can be returned as
3790** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
3791** the database name, the _table_ routines return the table name, and
3792** the origin_ routines return the column name.
3793** ^The returned string is valid until the [prepared statement] is destroyed
3794** using [sqlite3_finalize()] or until the statement is automatically
3795** reprepared by the first call to [sqlite3_step()] for a particular run
3796** or until the same information is requested
3797** again in a different encoding.
3799** ^The names returned are the original un-aliased names of the
3800** database, table, and column.
3802** ^The first argument to these interfaces is a [prepared statement].
3803** ^These functions return information about the Nth result column returned by
3804** the statement, where N is the second function argument.
3805** ^The left-most column is column 0 for these routines.
3807** ^If the Nth column returned by the statement is an expression or
3808** subquery and is not a column value, then all of these functions return
3809** NULL.  ^These routine might also return NULL if a memory allocation error
3810** occurs.  ^Otherwise, they return the name of the attached database, table,
3811** or column that query result column was extracted from.
3813** ^As with all other SQLite APIs, those whose names end with "16" return
3814** UTF-16 encoded strings and the other functions return UTF-8.
3816** ^These APIs are only available if the library was compiled with the
3817** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3819** If two or more threads call one or more of these routines against the same
3820** prepared statement and column at the same time then the results are
3821** undefined.
3823** If two or more threads call one or more
3824** [sqlite3_column_database_name | column metadata interfaces]
3825** for the same [prepared statement] and result column
3826** at the same time then the results are undefined.
3828SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
3829SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
3830SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
3831SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
3832SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
3833SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
3836** CAPI3REF: Declared Datatype Of A Query Result
3838** ^(The first parameter is a [prepared statement].
3839** If this statement is a [SELECT] statement and the Nth column of the
3840** returned result set of that [SELECT] is a table column (not an
3841** expression or subquery) then the declared type of the table
3842** column is returned.)^  ^If the Nth column of the result set is an
3843** expression or subquery, then a NULL pointer is returned.
3844** ^The returned string is always UTF-8 encoded.
3846** ^(For example, given the database schema:
3850** and the following statement to be compiled:
3852** SELECT c1 + 1, c1 FROM t1;
3854** this routine would return the string "VARIANT" for the second result
3855** column (i==1), and a NULL pointer for the first result column (i==0).)^
3857** ^SQLite uses dynamic run-time typing.  ^So just because a column
3858** is declared to contain a particular type does not mean that the
3859** data stored in that column is of the declared type.  SQLite is
3860** strongly typed, but the typing is dynamic not static.  ^Type
3861** is associated with individual values, not with the containers
3862** used to hold those values.
3864SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
3865SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
3868** CAPI3REF: Evaluate An SQL Statement
3870** After a [prepared statement] has been prepared using either
3871** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3872** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3873** must be called one or more times to evaluate the statement.
3875** The details of the behavior of the sqlite3_step() interface depend
3876** on whether the statement was prepared using the newer "v2" interface
3877** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3878** interface [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
3879** new "v2" interface is recommended for new applications but the legacy
3880** interface will continue to be supported.
3882** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3884** ^With the "v2" interface, any of the other [result codes] or
3885** [extended result codes] might be returned as well.
3887** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3888** database locks it needs to do its job.  ^If the statement is a [COMMIT]
3889** or occurs outside of an explicit transaction, then you can retry the
3890** statement.  If the statement is not a [COMMIT] and occurs within an
3891** explicit transaction then you should rollback the transaction before
3892** continuing.
3894** ^[SQLITE_DONE] means that the statement has finished executing
3895** successfully.  sqlite3_step() should not be called again on this virtual
3896** machine without first calling [sqlite3_reset()] to reset the virtual
3897** machine back to its initial state.
3899** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3900** is returned each time a new row of data is ready for processing by the
3901** caller. The values may be accessed using the [column access functions].
3902** sqlite3_step() is called again to retrieve the next row of data.
3904** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3905** violation) has occurred.  sqlite3_step() should not be called again on
3906** the VM. More information may be found by calling [sqlite3_errmsg()].
3907** ^With the legacy interface, a more specific error code (for example,
3909** can be obtained by calling [sqlite3_reset()] on the
3910** [prepared statement].  ^In the "v2" interface,
3911** the more specific error code is returned directly by sqlite3_step().
3913** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3914** Perhaps it was called on a [prepared statement] that has
3915** already been [sqlite3_finalize | finalized] or on one that had
3916** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
3917** be the case that the same database connection is being used by two or
3918** more threads at the same moment in time.
3920** For all versions of SQLite up to and including, a call to
3921** [sqlite3_reset()] was required after sqlite3_step() returned anything
3922** other than [SQLITE_ROW] before any subsequent invocation of
3923** sqlite3_step().  Failure to reset the prepared statement using
3924** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3925** sqlite3_step().  But after version, sqlite3_step() began
3926** calling [sqlite3_reset()] automatically in this circumstance rather
3927** than returning [SQLITE_MISUSE].  This is not considered a compatibility
3928** break because any application that ever receives an SQLITE_MISUSE error
3929** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
3930** can be used to restore the legacy behavior.
3932** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3933** API always returns a generic error code, [SQLITE_ERROR], following any
3934** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
3935** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3936** specific [error codes] that better describes the error.
3937** We admit that this is a goofy design.  The problem has been fixed
3938** with the "v2" interface.  If you prepare all of your SQL statements
3939** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3940** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3941** then the more specific [error codes] are returned directly
3942** by sqlite3_step().  The use of the "v2" interface is recommended.
3944SQLITE_API int sqlite3_step(sqlite3_stmt*);
3947** CAPI3REF: Number of columns in a result set
3949** ^The sqlite3_data_count(P) interface returns the number of columns in the
3950** current row of the result set of [prepared statement] P.
3951** ^If prepared statement P does not have results ready to return
3952** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3953** interfaces) then sqlite3_data_count(P) returns 0.
3954** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3955** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
3956** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
3957** will return non-zero if previous call to [sqlite3_step](P) returned
3958** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
3959** where it always returns zero since each step of that multi-step
3960** pragma returns 0 columns of data.
3962** See also: [sqlite3_column_count()]
3964SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
3967** CAPI3REF: Fundamental Datatypes
3970** ^(Every value in SQLite has one of five fundamental datatypes:
3972** <ul>
3973** <li> 64-bit signed integer
3974** <li> 64-bit IEEE floating point number
3975** <li> string
3976** <li> BLOB
3977** <li> NULL
3978** </ul>)^
3980** These constants are codes for each of those types.
3982** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3983** for a completely different meaning.  Software that links against both
3984** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3987#define SQLITE_INTEGER  1
3988#define SQLITE_FLOAT    2
3989#define SQLITE_BLOB     4
3990#define SQLITE_NULL     5
3991#ifdef SQLITE_TEXT
3992# undef SQLITE_TEXT
3994# define SQLITE_TEXT     3
3996#define SQLITE3_TEXT     3
3999** CAPI3REF: Result Values From A Query
4000** KEYWORDS: {column access functions}
4002** These routines form the "result set" interface.
4004** ^These routines return information about a single column of the current
4005** result row of a query.  ^In every case the first argument is a pointer
4006** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
4007** that was returned from [sqlite3_prepare_v2()] or one of its variants)
4008** and the second argument is the index of the column for which information
4009** should be returned. ^The leftmost column of the result set has the index 0.
4010** ^The number of columns in the result can be determined using
4011** [sqlite3_column_count()].
4013** If the SQL statement does not currently point to a valid row, or if the
4014** column index is out of range, the result is undefined.
4015** These routines may only be called when the most recent call to
4016** [sqlite3_step()] has returned [SQLITE_ROW] and neither
4017** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
4018** If any of these routines are called after [sqlite3_reset()] or
4019** [sqlite3_finalize()] or after [sqlite3_step()] has returned
4020** something other than [SQLITE_ROW], the results are undefined.
4021** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
4022** are called from a different thread while any of these routines
4023** are pending, then the results are undefined.
4025** ^The sqlite3_column_type() routine returns the
4026** [SQLITE_INTEGER | datatype code] for the initial data type
4027** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
4029** returned by sqlite3_column_type() is only meaningful if no type
4030** conversions have occurred as described below.  After a type conversion,
4031** the value returned by sqlite3_column_type() is undefined.  Future
4032** versions of SQLite may change the behavior of sqlite3_column_type()
4033** following a type conversion.
4035** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
4036** routine returns the number of bytes in that BLOB or string.
4037** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
4038** the string to UTF-8 and then returns the number of bytes.
4039** ^If the result is a numeric value then sqlite3_column_bytes() uses
4040** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
4041** the number of bytes in that string.
4042** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
4044** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
4045** routine returns the number of bytes in that BLOB or string.
4046** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
4047** the string to UTF-16 and then returns the number of bytes.
4048** ^If the result is a numeric value then sqlite3_column_bytes16() uses
4049** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
4050** the number of bytes in that string.
4051** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
4053** ^The values returned by [sqlite3_column_bytes()] and
4054** [sqlite3_column_bytes16()] do not include the zero terminators at the end
4055** of the string.  ^For clarity: the values returned by
4056** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
4057** bytes in the string, not the number of characters.
4059** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
4060** even empty strings, are always zero-terminated.  ^The return
4061** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
4063** ^The object returned by [sqlite3_column_value()] is an
4064** [unprotected sqlite3_value] object.  An unprotected sqlite3_value object
4065** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
4066** If the [unprotected sqlite3_value] object returned by
4067** [sqlite3_column_value()] is used in any other way, including calls
4068** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
4069** or [sqlite3_value_bytes()], then the behavior is undefined.
4071** These routines attempt to convert the value where appropriate.  ^For
4072** example, if the internal representation is FLOAT and a text result
4073** is requested, [sqlite3_snprintf()] is used internally to perform the
4074** conversion automatically.  ^(The following table details the conversions
4075** that are applied:
4077** <blockquote>
4078** <table border="1">
4079** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
4081** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
4082** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
4083** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
4084** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
4085** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
4086** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
4087** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
4088** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
4089** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
4090** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
4091** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
4092** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
4093** <tr><td>  TEXT    <td>   BLOB    <td> No change
4094** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
4095** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
4096** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
4097** </table>
4098** </blockquote>)^
4100** The table above makes reference to standard C library functions atoi()
4101** and atof().  SQLite does not really use these functions.  It has its
4102** own equivalent internal routines.  The atoi() and atof() names are
4103** used in the table for brevity and because they are familiar to most
4104** C programmers.
4106** Note that when type conversions occur, pointers returned by prior
4107** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
4108** sqlite3_column_text16() may be invalidated.
4109** Type conversions and pointer invalidations might occur
4110** in the following cases:
4112** <ul>
4113** <li> The initial content is a BLOB and sqlite3_column_text() or
4114**      sqlite3_column_text16() is called.  A zero-terminator might
4115**      need to be added to the string.</li>
4116** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
4117**      sqlite3_column_text16() is called.  The content must be converted
4118**      to UTF-16.</li>
4119** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
4120**      sqlite3_column_text() is called.  The content must be converted
4121**      to UTF-8.</li>
4122** </ul>
4124** ^Conversions between UTF-16be and UTF-16le are always done in place and do
4125** not invalidate a prior pointer, though of course the content of the buffer
4126** that the prior pointer references will have been modified.  Other kinds
4127** of conversion are done in place when it is possible, but sometimes they
4128** are not possible and in those cases prior pointers are invalidated.
4130** The safest and easiest to remember policy is to invoke these routines
4131** in one of the following ways:
4133** <ul>
4134**  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
4135**  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
4136**  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
4137** </ul>
4139** In other words, you should call sqlite3_column_text(),
4140** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
4141** into the desired format, then invoke sqlite3_column_bytes() or
4142** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
4143** to sqlite3_column_text() or sqlite3_column_blob() with calls to
4144** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
4145** with calls to sqlite3_column_bytes().
4147** ^The pointers returned are valid until a type conversion occurs as
4148** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
4149** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
4150** and BLOBs is freed automatically.  Do <b>not</b> pass the pointers returned
4151** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
4152** [sqlite3_free()].
4154** ^(If a memory allocation error occurs during the evaluation of any
4155** of these routines, a default value is returned.  The default value
4156** is either the integer 0, the floating point number 0.0, or a NULL
4157** pointer.  Subsequent calls to [sqlite3_errcode()] will return
4158** [SQLITE_NOMEM].)^
4160SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
4161SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
4162SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
4163SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
4164SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
4165SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
4166SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
4167SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
4168SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
4169SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
4172** CAPI3REF: Destroy A Prepared Statement Object
4174** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4175** ^If the most recent evaluation of the statement encountered no errors
4176** or if the statement is never been evaluated, then sqlite3_finalize() returns
4177** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
4178** sqlite3_finalize(S) returns the appropriate [error code] or
4179** [extended error code].
4181** ^The sqlite3_finalize(S) routine can be called at any point during
4182** the life cycle of [prepared statement] S:
4183** before statement S is ever evaluated, after
4184** one or more calls to [sqlite3_reset()], or after any call
4185** to [sqlite3_step()] regardless of whether or not the statement has
4186** completed execution.
4188** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4190** The application must finalize every [prepared statement] in order to avoid
4191** resource leaks.  It is a grievous error for the application to try to use
4192** a prepared statement after it has been finalized.  Any use of a prepared
4193** statement after it has been finalized can result in undefined and
4194** undesirable behavior such as segfaults and heap corruption.
4196SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
4199** CAPI3REF: Reset A Prepared Statement Object
4201** The sqlite3_reset() function is called to reset a [prepared statement]
4202** object back to its initial state, ready to be re-executed.
4203** ^Any SQL statement variables that had values bound to them using
4204** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4205** Use [sqlite3_clear_bindings()] to reset the bindings.
4207** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4208** back to the beginning of its program.
4210** ^If the most recent call to [sqlite3_step(S)] for the
4211** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4212** or if [sqlite3_step(S)] has never before been called on S,
4213** then [sqlite3_reset(S)] returns [SQLITE_OK].
4215** ^If the most recent call to [sqlite3_step(S)] for the
4216** [prepared statement] S indicated an error, then
4217** [sqlite3_reset(S)] returns an appropriate [error code].
4219** ^The [sqlite3_reset(S)] interface does not change the values
4220** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4222SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
4225** CAPI3REF: Create Or Redefine SQL Functions
4226** KEYWORDS: {function creation routines}
4227** KEYWORDS: {application-defined SQL function}
4228** KEYWORDS: {application-defined SQL functions}
4230** ^These functions (collectively known as "function creation routines")
4231** are used to add SQL functions or aggregates or to redefine the behavior
4232** of existing SQL functions or aggregates.  The only differences between
4233** these routines are the text encoding expected for
4234** the second parameter (the name of the function being created)
4235** and the presence or absence of a destructor callback for
4236** the application data pointer.
4238** ^The first parameter is the [database connection] to which the SQL
4239** function is to be added.  ^If an application uses more than one database
4240** connection then application-defined SQL functions must be added
4241** to each database connection separately.
4243** ^The second parameter is the name of the SQL function to be created or
4244** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
4245** representation, exclusive of the zero-terminator.  ^Note that the name
4246** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4247** ^Any attempt to create a function with a longer name
4248** will result in [SQLITE_MISUSE] being returned.
4250** ^The third parameter (nArg)
4251** is the number of arguments that the SQL function or
4252** aggregate takes. ^If this parameter is -1, then the SQL function or
4253** aggregate may take any number of arguments between 0 and the limit
4254** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
4255** parameter is less than -1 or greater than 127 then the behavior is
4256** undefined.
4258** ^The fourth parameter, eTextRep, specifies what
4259** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4260** its parameters.  The application should set this parameter to
4261** [SQLITE_UTF16LE] if the function implementation invokes
4262** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4263** implementation invokes [sqlite3_value_text16be()] on an input, or
4264** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4265** otherwise.  ^The same SQL function may be registered multiple times using
4266** different preferred text encodings, with different implementations for
4267** each encoding.
4268** ^When multiple implementations of the same function are available, SQLite
4269** will pick the one that involves the least amount of data conversion.
4271** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4272** to signal that the function will always return the same result given
4273** the same inputs within a single SQL statement.  Most SQL functions are
4274** deterministic.  The built-in [random()] SQL function is an example of a
4275** function that is not deterministic.  The SQLite query planner is able to
4276** perform additional optimizations on deterministic functions, so use
4277** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4279** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
4280** function can gain access to this pointer using [sqlite3_user_data()].)^
4282** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
4283** pointers to C-language functions that implement the SQL function or
4284** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4285** callback only; NULL pointers must be passed as the xStep and xFinal
4286** parameters. ^An aggregate SQL function requires an implementation of xStep
4287** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4288** SQL function or aggregate, pass NULL pointers for all three function
4289** callbacks.
4291** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
4292** then it is destructor for the application data pointer.
4293** The destructor is invoked when the function is deleted, either by being
4294** overloaded or when the database connection closes.)^
4295** ^The destructor is also invoked if the call to
4296** sqlite3_create_function_v2() fails.
4297** ^When the destructor callback of the tenth parameter is invoked, it
4298** is passed a single argument which is a copy of the application data
4299** pointer which was the fifth parameter to sqlite3_create_function_v2().
4301** ^It is permitted to register multiple implementations of the same
4302** functions with the same name but with either differing numbers of
4303** arguments or differing preferred text encodings.  ^SQLite will use
4304** the implementation that most closely matches the way in which the
4305** SQL function is used.  ^A function implementation with a non-negative
4306** nArg parameter is a better match than a function implementation with
4307** a negative nArg.  ^A function where the preferred text encoding
4308** matches the database encoding is a better
4309** match than a function where the encoding is different.
4310** ^A function where the encoding difference is between UTF16le and UTF16be
4311** is a closer match than a function where the encoding difference is
4312** between UTF8 and UTF16.
4314** ^Built-in functions may be overloaded by new application-defined functions.
4316** ^An application-defined function is permitted to call other
4317** SQLite interfaces.  However, such calls must not
4318** close the database connection nor finalize or reset the prepared
4319** statement in which the function is running.
4321SQLITE_API int sqlite3_create_function(
4322  sqlite3 *db,
4323  const char *zFunctionName,
4324  int nArg,
4325  int eTextRep,
4326  void *pApp,
4327  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4328  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4329  void (*xFinal)(sqlite3_context*)
4331SQLITE_API int sqlite3_create_function16(
4332  sqlite3 *db,
4333  const void *zFunctionName,
4334  int nArg,
4335  int eTextRep,
4336  void *pApp,
4337  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4338  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4339  void (*xFinal)(sqlite3_context*)
4341SQLITE_API int sqlite3_create_function_v2(
4342  sqlite3 *db,
4343  const char *zFunctionName,
4344  int nArg,
4345  int eTextRep,
4346  void *pApp,
4347  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4348  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4349  void (*xFinal)(sqlite3_context*),
4350  void(*xDestroy)(void*)
4354** CAPI3REF: Text Encodings
4356** These constant define integer codes that represent the various
4357** text encodings supported by SQLite.
4359#define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
4360#define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
4361#define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
4362#define SQLITE_UTF16          4    /* Use native byte order */
4363#define SQLITE_ANY            5    /* Deprecated */
4364#define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
4367** CAPI3REF: Function Flags
4369** These constants may be ORed together with the
4370** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4371** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4372** [sqlite3_create_function_v2()].
4374#define SQLITE_DETERMINISTIC    0x800
4377** CAPI3REF: Deprecated Functions
4380** These functions are [deprecated].  In order to maintain
4381** backwards compatibility with older code, these functions continue
4382** to be supported.  However, new applications should avoid
4383** the use of these functions.  To help encourage people to avoid
4384** using these functions, we are not going to tell you what they do.
4387SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
4388SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
4389SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4390SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
4391SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
4392SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4393                      void*,sqlite3_int64);
4397** CAPI3REF: Obtaining SQL Function Parameter Values
4399** The C-language implementation of SQL functions and aggregates uses
4400** this set of interface routines to access the parameter values on
4401** the function or aggregate.
4403** The xFunc (for scalar functions) or xStep (for aggregates) parameters
4404** to [sqlite3_create_function()] and [sqlite3_create_function16()]
4405** define callbacks that implement the SQL functions and aggregates.
4406** The 3rd parameter to these callbacks is an array of pointers to
4407** [protected sqlite3_value] objects.  There is one [sqlite3_value] object for
4408** each parameter to the SQL function.  These routines are used to
4409** extract values from the [sqlite3_value] objects.
4411** These routines work only with [protected sqlite3_value] objects.
4412** Any attempt to use these routines on an [unprotected sqlite3_value]
4413** object results in undefined behavior.
4415** ^These routines work just like the corresponding [column access functions]
4416** except that these routines take a single [protected sqlite3_value] object
4417** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4419** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4420** in the native byte-order of the host machine.  ^The
4421** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4422** extract UTF-16 strings as big-endian and little-endian respectively.
4424** ^(The sqlite3_value_numeric_type() interface attempts to apply
4425** numeric affinity to the value.  This means that an attempt is
4426** made to convert the value to an integer or floating point.  If
4427** such a conversion is possible without loss of information (in other
4428** words, if the value is a string that looks like a number)
4429** then the conversion is performed.  Otherwise no conversion occurs.
4430** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4432** Please pay particular attention to the fact that the pointer returned
4433** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4434** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4435** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4436** or [sqlite3_value_text16()].
4438** These routines must be called from the same thread as
4439** the SQL function that supplied the [sqlite3_value*] parameters.
4441SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
4442SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
4443SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
4444SQLITE_API double sqlite3_value_double(sqlite3_value*);
4445SQLITE_API int sqlite3_value_int(sqlite3_value*);
4446SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
4447SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
4448SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
4449SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
4450SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
4451SQLITE_API int sqlite3_value_type(sqlite3_value*);
4452SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
4455** CAPI3REF: Obtain Aggregate Function Context
4457** Implementations of aggregate SQL functions use this
4458** routine to allocate memory for storing their state.
4460** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4461** for a particular aggregate function, SQLite
4462** allocates N of memory, zeroes out that memory, and returns a pointer
4463** to the new memory. ^On second and subsequent calls to
4464** sqlite3_aggregate_context() for the same aggregate function instance,
4465** the same buffer is returned.  Sqlite3_aggregate_context() is normally
4466** called once for each invocation of the xStep callback and then one
4467** last time when the xFinal callback is invoked.  ^(When no rows match
4468** an aggregate query, the xStep() callback of the aggregate function
4469** implementation is never called and xFinal() is called exactly once.
4470** In those cases, sqlite3_aggregate_context() might be called for the
4471** first time from within xFinal().)^
4473** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
4474** when first called if N is less than or equal to zero or if a memory
4475** allocate error occurs.
4477** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4478** determined by the N parameter on first successful call.  Changing the
4479** value of N in subsequent call to sqlite3_aggregate_context() within
4480** the same aggregate function instance will not resize the memory
4481** allocation.)^  Within the xFinal callback, it is customary to set
4482** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
4483** pointless memory allocations occur.
4485** ^SQLite automatically frees the memory allocated by
4486** sqlite3_aggregate_context() when the aggregate query concludes.
4488** The first parameter must be a copy of the
4489** [sqlite3_context | SQL function context] that is the first parameter
4490** to the xStep or xFinal callback routine that implements the aggregate
4491** function.
4493** This routine must be called from the same thread in which
4494** the aggregate SQL function is running.
4496SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4499** CAPI3REF: User Data For Functions
4501** ^The sqlite3_user_data() interface returns a copy of
4502** the pointer that was the pUserData parameter (the 5th parameter)
4503** of the [sqlite3_create_function()]
4504** and [sqlite3_create_function16()] routines that originally
4505** registered the application defined function.
4507** This routine must be called from the same thread in which
4508** the application-defined function is running.
4510SQLITE_API void *sqlite3_user_data(sqlite3_context*);
4513** CAPI3REF: Database Connection For Functions
4515** ^The sqlite3_context_db_handle() interface returns a copy of
4516** the pointer to the [database connection] (the 1st parameter)
4517** of the [sqlite3_create_function()]
4518** and [sqlite3_create_function16()] routines that originally
4519** registered the application defined function.
4521SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
4524** CAPI3REF: Function Auxiliary Data
4526** These functions may be used by (non-aggregate) SQL functions to
4527** associate metadata with argument values. If the same value is passed to
4528** multiple invocations of the same SQL function during query execution, under
4529** some circumstances the associated metadata may be preserved.  An example
4530** of where this might be useful is in a regular-expression matching
4531** function. The compiled version of the regular expression can be stored as
4532** metadata associated with the pattern string.
4533** Then as long as the pattern string remains the same,
4534** the compiled regular expression can be reused on multiple
4535** invocations of the same function.
4537** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
4538** associated by the sqlite3_set_auxdata() function with the Nth argument
4539** value to the application-defined function. ^If there is no metadata
4540** associated with the function argument, this sqlite3_get_auxdata() interface
4541** returns a NULL pointer.
4543** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
4544** argument of the application-defined function.  ^Subsequent
4545** calls to sqlite3_get_auxdata(C,N) return P from the most recent
4546** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
4547** NULL if the metadata has been discarded.
4548** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
4549** SQLite will invoke the destructor function X with parameter P exactly
4550** once, when the metadata is discarded.
4551** SQLite is free to discard the metadata at any time, including: <ul>
4552** <li> when the corresponding function parameter changes, or
4553** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
4554**      SQL statement, or
4555** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or
4556** <li> during the original sqlite3_set_auxdata() call when a memory
4557**      allocation error occurs. </ul>)^
4559** Note the last bullet in particular.  The destructor X in
4560** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
4561** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
4562** should be called near the end of the function implementation and the
4563** function implementation should not make any use of P after
4564** sqlite3_set_auxdata() has been called.
4566** ^(In practice, metadata is preserved between function calls for
4567** function parameters that are compile-time constants, including literal
4568** values and [parameters] and expressions composed from the same.)^
4570** These routines must be called from the same thread in which
4571** the SQL function is running.
4573SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
4574SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
4578** CAPI3REF: Constants Defining Special Destructor Behavior
4580** These are special values for the destructor that is passed in as the
4581** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
4582** argument is SQLITE_STATIC, it means that the content pointer is constant
4583** and will never change.  It does not need to be destroyed.  ^The
4584** SQLITE_TRANSIENT value means that the content will likely change in
4585** the near future and that SQLite should make its own private copy of
4586** the content before returning.
4588** The typedef is necessary to work around problems in certain
4589** C++ compilers.
4591typedef void (*sqlite3_destructor_type)(void*);
4592#define SQLITE_STATIC      ((sqlite3_destructor_type)0)
4593#define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
4596** CAPI3REF: Setting The Result Of An SQL Function
4598** These routines are used by the xFunc or xFinal callbacks that
4599** implement SQL functions and aggregates.  See
4600** [sqlite3_create_function()] and [sqlite3_create_function16()]
4601** for additional information.
4603** These functions work very much like the [parameter binding] family of
4604** functions used to bind values to host parameters in prepared statements.
4605** Refer to the [SQL parameter] documentation for additional information.
4607** ^The sqlite3_result_blob() interface sets the result from
4608** an application-defined function to be the BLOB whose content is pointed
4609** to by the second parameter and which is N bytes long where N is the
4610** third parameter.
4612** ^The sqlite3_result_zeroblob() interfaces set the result of
4613** the application-defined function to be a BLOB containing all zero
4614** bytes and N bytes in size, where N is the value of the 2nd parameter.
4616** ^The sqlite3_result_double() interface sets the result from
4617** an application-defined function to be a floating point value specified
4618** by its 2nd argument.
4620** ^The sqlite3_result_error() and sqlite3_result_error16() functions
4621** cause the implemented SQL function to throw an exception.
4622** ^SQLite uses the string pointed to by the
4623** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
4624** as the text of an error message.  ^SQLite interprets the error
4625** message string from sqlite3_result_error() as UTF-8. ^SQLite
4626** interprets the string from sqlite3_result_error16() as UTF-16 in native
4627** byte order.  ^If the third parameter to sqlite3_result_error()
4628** or sqlite3_result_error16() is negative then SQLite takes as the error
4629** message all text up through the first zero character.
4630** ^If the third parameter to sqlite3_result_error() or
4631** sqlite3_result_error16() is non-negative then SQLite takes that many
4632** bytes (not characters) from the 2nd parameter as the error message.
4633** ^The sqlite3_result_error() and sqlite3_result_error16()
4634** routines make a private copy of the error message text before
4635** they return.  Hence, the calling function can deallocate or
4636** modify the text after they return without harm.
4637** ^The sqlite3_result_error_code() function changes the error code
4638** returned by SQLite as a result of an error in a function.  ^By default,
4639** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
4640** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
4642** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
4643** error indicating that a string or BLOB is too long to represent.
4645** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
4646** error indicating that a memory allocation failed.
4648** ^The sqlite3_result_int() interface sets the return value
4649** of the application-defined function to be the 32-bit signed integer
4650** value given in the 2nd argument.
4651** ^The sqlite3_result_int64() interface sets the return value
4652** of the application-defined function to be the 64-bit signed integer
4653** value given in the 2nd argument.
4655** ^The sqlite3_result_null() interface sets the return value
4656** of the application-defined function to be NULL.
4658** ^The sqlite3_result_text(), sqlite3_result_text16(),
4659** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
4660** set the return value of the application-defined function to be
4661** a text string which is represented as UTF-8, UTF-16 native byte order,
4662** UTF-16 little endian, or UTF-16 big endian, respectively.
4663** ^The sqlite3_result_text64() interface sets the return value of an
4664** application-defined function to be a text string in an encoding
4665** specified by the fifth (and last) parameter, which must be one
4667** ^SQLite takes the text result from the application from
4668** the 2nd parameter of the sqlite3_result_text* interfaces.
4669** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4670** is negative, then SQLite takes result text from the 2nd parameter
4671** through the first zero character.
4672** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4673** is non-negative, then as many bytes (not characters) of the text
4674** pointed to by the 2nd parameter are taken as the application-defined
4675** function result.  If the 3rd parameter is non-negative, then it
4676** must be the byte offset into the string where the NUL terminator would
4677** appear if the string where NUL terminated.  If any NUL characters occur
4678** in the string at a byte offset that is less than the value of the 3rd
4679** parameter, then the resulting string will contain embedded NULs and the
4680** result of expressions operating on strings with embedded NULs is undefined.
4681** ^If the 4th parameter to the sqlite3_result_text* interfaces
4682** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4683** function as the destructor on the text or BLOB result when it has
4684** finished using that result.
4685** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4686** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4687** assumes that the text or BLOB result is in constant space and does not
4688** copy the content of the parameter nor call a destructor on the content
4689** when it has finished using that result.
4690** ^If the 4th parameter to the sqlite3_result_text* interfaces
4691** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4692** then SQLite makes a copy of the result into space obtained from
4693** from [sqlite3_malloc()] before it returns.
4695** ^The sqlite3_result_value() interface sets the result of
4696** the application-defined function to be a copy the
4697** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
4698** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4699** so that the [sqlite3_value] specified in the parameter may change or
4700** be deallocated after sqlite3_result_value() returns without harm.
4701** ^A [protected sqlite3_value] object may always be used where an
4702** [unprotected sqlite3_value] object is required, so either
4703** kind of [sqlite3_value] object can be used with this interface.
4705** If these routines are called from within the different thread
4706** than the one containing the application-defined function that received
4707** the [sqlite3_context] pointer, the results are undefined.
4709SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4710SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
4711                           sqlite3_uint64,void(*)(void*));
4712SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
4713SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
4714SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
4715SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
4716SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
4717SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
4718SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
4719SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4720SQLITE_API void sqlite3_result_null(sqlite3_context*);
4721SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4722SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
4723                           void(*)(void*), unsigned char encoding);
4724SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4725SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4726SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4727SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4728SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
4731** CAPI3REF: Define New Collating Sequences
4733** ^These functions add, remove, or modify a [collation] associated
4734** with the [database connection] specified as the first argument.
4736** ^The name of the collation is a UTF-8 string
4737** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4738** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4739** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4740** considered to be the same name.
4742** ^(The third argument (eTextRep) must be one of the constants:
4743** <ul>
4744** <li> [SQLITE_UTF8],
4745** <li> [SQLITE_UTF16LE],
4746** <li> [SQLITE_UTF16BE],
4747** <li> [SQLITE_UTF16], or
4748** <li> [SQLITE_UTF16_ALIGNED].
4749** </ul>)^
4750** ^The eTextRep argument determines the encoding of strings passed
4751** to the collating function callback, xCallback.
4752** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4753** force strings to be UTF16 with native byte order.
4754** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4755** on an even byte address.
4757** ^The fourth argument, pArg, is an application data pointer that is passed
4758** through as the first argument to the collating function callback.
4760** ^The fifth argument, xCallback, is a pointer to the collating function.
4761** ^Multiple collating functions can be registered using the same name but
4762** with different eTextRep parameters and SQLite will use whichever
4763** function requires the least amount of data transformation.
4764** ^If the xCallback argument is NULL then the collating function is
4765** deleted.  ^When all collating functions having the same name are deleted,
4766** that collation is no longer usable.
4768** ^The collating function callback is invoked with a copy of the pArg
4769** application data pointer and with two strings in the encoding specified
4770** by the eTextRep argument.  The collating function must return an
4771** integer that is negative, zero, or positive
4772** if the first string is less than, equal to, or greater than the second,
4773** respectively.  A collating function must always return the same answer
4774** given the same inputs.  If two or more collating functions are registered
4775** to the same collation name (using different eTextRep values) then all
4776** must give an equivalent answer when invoked with equivalent strings.
4777** The collating function must obey the following properties for all
4778** strings A, B, and C:
4780** <ol>
4781** <li> If A==B then B==A.
4782** <li> If A==B and B==C then A==C.
4783** <li> If A&lt;B THEN B&gt;A.
4784** <li> If A&lt;B and B&lt;C then A&lt;C.
4785** </ol>
4787** If a collating function fails any of the above constraints and that
4788** collating function is  registered and used, then the behavior of SQLite
4789** is undefined.
4791** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4792** with the addition that the xDestroy callback is invoked on pArg when
4793** the collating function is deleted.
4794** ^Collating functions are deleted when they are overridden by later
4795** calls to the collation creation functions or when the
4796** [database connection] is closed using [sqlite3_close()].
4798** ^The xDestroy callback is <u>not</u> called if the
4799** sqlite3_create_collation_v2() function fails.  Applications that invoke
4800** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4801** check the return code and dispose of the application data pointer
4802** themselves rather than expecting SQLite to deal with it for them.
4803** This is different from every other SQLite interface.  The inconsistency
4804** is unfortunate but cannot be changed without breaking backwards
4805** compatibility.
4807** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4809SQLITE_API int sqlite3_create_collation(
4810  sqlite3*,
4811  const char *zName,
4812  int eTextRep,
4813  void *pArg,
4814  int(*xCompare)(void*,int,const void*,int,const void*)
4816SQLITE_API int sqlite3_create_collation_v2(
4817  sqlite3*,
4818  const char *zName,
4819  int eTextRep,
4820  void *pArg,
4821  int(*xCompare)(void*,int,const void*,int,const void*),
4822  void(*xDestroy)(void*)
4824SQLITE_API int sqlite3_create_collation16(
4825  sqlite3*,
4826  const void *zName,
4827  int eTextRep,
4828  void *pArg,
4829  int(*xCompare)(void*,int,const void*,int,const void*)
4833** CAPI3REF: Collation Needed Callbacks
4835** ^To avoid having to register all collation sequences before a database
4836** can be used, a single callback function may be registered with the
4837** [database connection] to be invoked whenever an undefined collation
4838** sequence is required.
4840** ^If the function is registered using the sqlite3_collation_needed() API,
4841** then it is passed the names of undefined collation sequences as strings
4842** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4843** the names are passed as UTF-16 in machine native byte order.
4844** ^A call to either function replaces the existing collation-needed callback.
4846** ^(When the callback is invoked, the first argument passed is a copy
4847** of the second argument to sqlite3_collation_needed() or
4848** sqlite3_collation_needed16().  The second argument is the database
4849** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4850** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4851** sequence function required.  The fourth parameter is the name of the
4852** required collation sequence.)^
4854** The callback function should register the desired collation using
4855** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4856** [sqlite3_create_collation_v2()].
4858SQLITE_API int sqlite3_collation_needed(
4859  sqlite3*,
4860  void*,
4861  void(*)(void*,sqlite3*,int eTextRep,const char*)
4863SQLITE_API int sqlite3_collation_needed16(
4864  sqlite3*,
4865  void*,
4866  void(*)(void*,sqlite3*,int eTextRep,const void*)
4871** Specify the key for an encrypted database.  This routine should be
4872** called right after sqlite3_open().
4874** The code to implement this API is not available in the public release
4875** of SQLite.
4877SQLITE_API int sqlite3_key(
4878  sqlite3 *db,                   /* Database to be rekeyed */
4879  const void *pKey, int nKey     /* The key */
4881SQLITE_API int sqlite3_key_v2(
4882  sqlite3 *db,                   /* Database to be rekeyed */
4883  const char *zDbName,           /* Name of the database */
4884  const void *pKey, int nKey     /* The key */
4888** Change the key on an open database.  If the current database is not
4889** encrypted, this routine will encrypt it.  If pNew==0 or nNew==0, the
4890** database is decrypted.
4892** The code to implement this API is not available in the public release
4893** of SQLite.
4895SQLITE_API int sqlite3_rekey(
4896  sqlite3 *db,                   /* Database to be rekeyed */
4897  const void *pKey, int nKey     /* The new key */
4899SQLITE_API int sqlite3_rekey_v2(
4900  sqlite3 *db,                   /* Database to be rekeyed */
4901  const char *zDbName,           /* Name of the database */
4902  const void *pKey, int nKey     /* The new key */
4906** Specify the activation key for a SEE database.  Unless
4907** activated, none of the SEE routines will work.
4909SQLITE_API void sqlite3_activate_see(
4910  const char *zPassPhrase        /* Activation phrase */
4916** Specify the activation key for a CEROD database.  Unless
4917** activated, none of the CEROD routines will work.
4919SQLITE_API void sqlite3_activate_cerod(
4920  const char *zPassPhrase        /* Activation phrase */
4925** CAPI3REF: Suspend Execution For A Short Time
4927** The sqlite3_sleep() function causes the current thread to suspend execution
4928** for at least a number of milliseconds specified in its parameter.
4930** If the operating system does not support sleep requests with
4931** millisecond time resolution, then the time will be rounded up to
4932** the nearest second. The number of milliseconds of sleep actually
4933** requested from the operating system is returned.
4935** ^SQLite implements this interface by calling the xSleep()
4936** method of the default [sqlite3_vfs] object.  If the xSleep() method
4937** of the default VFS is not implemented correctly, or not implemented at
4938** all, then the behavior of sqlite3_sleep() may deviate from the description
4939** in the previous paragraphs.
4941SQLITE_API int sqlite3_sleep(int);
4944** CAPI3REF: Name Of The Folder Holding Temporary Files
4946** ^(If this global variable is made to point to a string which is
4947** the name of a folder (a.k.a. directory), then all temporary files
4948** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4949** will be placed in that directory.)^  ^If this variable
4950** is a NULL pointer, then SQLite performs a search for an appropriate
4951** temporary file directory.
4953** Applications are strongly discouraged from using this global variable.
4954** It is required to set a temporary folder on Windows Runtime (WinRT).
4955** But for all other platforms, it is highly recommended that applications
4956** neither read nor write this variable.  This global variable is a relic
4957** that exists for backwards compatibility of legacy applications and should
4958** be avoided in new projects.
4960** It is not safe to read or modify this variable in more than one
4961** thread at a time.  It is not safe to read or modify this variable
4962** if a [database connection] is being used at the same time in a separate
4963** thread.
4964** It is intended that this variable be set once
4965** as part of process initialization and before any SQLite interface
4966** routines have been called and that this variable remain unchanged
4967** thereafter.
4969** ^The [temp_store_directory pragma] may modify this variable and cause
4970** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
4971** the [temp_store_directory pragma] always assumes that any string
4972** that this variable points to is held in memory obtained from
4973** [sqlite3_malloc] and the pragma may attempt to free that memory
4974** using [sqlite3_free].
4975** Hence, if this variable is modified directly, either it should be
4976** made NULL or made to point to memory obtained from [sqlite3_malloc]
4977** or else the use of the [temp_store_directory pragma] should be avoided.
4978** Except when requested by the [temp_store_directory pragma], SQLite
4979** does not free the memory that sqlite3_temp_directory points to.  If
4980** the application wants that memory to be freed, it must do
4981** so itself, taking care to only do so after all [database connection]
4982** objects have been destroyed.
4984** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
4985** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
4986** features that require the use of temporary files may fail.  Here is an
4987** example of how to do this using C++ with the Windows Runtime:
4989** <blockquote><pre>
4990** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
4991** &nbsp;     TemporaryFolder->Path->Data();
4992** char zPathBuf&#91;MAX_PATH + 1&#93;;
4993** memset(zPathBuf, 0, sizeof(zPathBuf));
4994** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
4995** &nbsp;     NULL, NULL);
4996** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
4997** </pre></blockquote>
4999SQLITE_API char *sqlite3_temp_directory;
5002** CAPI3REF: Name Of The Folder Holding Database Files
5004** ^(If this global variable is made to point to a string which is
5005** the name of a folder (a.k.a. directory), then all database files
5006** specified with a relative pathname and created or accessed by
5007** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
5008** to be relative to that directory.)^ ^If this variable is a NULL
5009** pointer, then SQLite assumes that all database files specified
5010** with a relative pathname are relative to the current directory
5011** for the process.  Only the windows VFS makes use of this global
5012** variable; it is ignored by the unix VFS.
5014** Changing the value of this variable while a database connection is
5015** open can result in a corrupt database.
5017** It is not safe to read or modify this variable in more than one
5018** thread at a time.  It is not safe to read or modify this variable
5019** if a [database connection] is being used at the same time in a separate
5020** thread.
5021** It is intended that this variable be set once
5022** as part of process initialization and before any SQLite interface
5023** routines have been called and that this variable remain unchanged
5024** thereafter.
5026** ^The [data_store_directory pragma] may modify this variable and cause
5027** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
5028** the [data_store_directory pragma] always assumes that any string
5029** that this variable points to is held in memory obtained from
5030** [sqlite3_malloc] and the pragma may attempt to free that memory
5031** using [sqlite3_free].
5032** Hence, if this variable is modified directly, either it should be
5033** made NULL or made to point to memory obtained from [sqlite3_malloc]
5034** or else the use of the [data_store_directory pragma] should be avoided.
5036SQLITE_API char *sqlite3_data_directory;
5039** CAPI3REF: Test For Auto-Commit Mode
5040** KEYWORDS: {autocommit mode}
5042** ^The sqlite3_get_autocommit() interface returns non-zero or
5043** zero if the given database connection is or is not in autocommit mode,
5044** respectively.  ^Autocommit mode is on by default.
5045** ^Autocommit mode is disabled by a [BEGIN] statement.
5046** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
5048** If certain kinds of errors occur on a statement within a multi-statement
5049** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
5051** transaction might be rolled back automatically.  The only way to
5052** find out whether SQLite automatically rolled back the transaction after
5053** an error is to use this function.
5055** If another thread changes the autocommit status of the database
5056** connection while this routine is running, then the return value
5057** is undefined.
5059SQLITE_API int sqlite3_get_autocommit(sqlite3*);
5062** CAPI3REF: Find The Database Handle Of A Prepared Statement
5064** ^The sqlite3_db_handle interface returns the [database connection] handle
5065** to which a [prepared statement] belongs.  ^The [database connection]
5066** returned by sqlite3_db_handle is the same [database connection]
5067** that was the first argument
5068** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
5069** create the statement in the first place.
5071SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
5074** CAPI3REF: Return The Filename For A Database Connection
5076** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
5077** associated with database N of connection D.  ^The main database file
5078** has the name "main".  If there is no attached database N on the database
5079** connection D, or if database N is a temporary or in-memory database, then
5080** a NULL pointer is returned.
5082** ^The filename returned by this function is the output of the
5083** xFullPathname method of the [VFS].  ^In other words, the filename
5084** will be an absolute pathname, even if the filename used
5085** to open the database originally was a URI or relative pathname.
5087SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
5090** CAPI3REF: Determine if a database is read-only
5092** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
5093** of connection D is read-only, 0 if it is read/write, or -1 if N is not
5094** the name of a database on connection D.
5096SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
5099** CAPI3REF: Find the next prepared statement
5101** ^This interface returns a pointer to the next [prepared statement] after
5102** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
5103** then this interface returns a pointer to the first prepared statement
5104** associated with the database connection pDb.  ^If no prepared statement
5105** satisfies the conditions of this routine, it returns NULL.
5107** The [database connection] pointer D in a call to
5108** [sqlite3_next_stmt(D,S)] must refer to an open database
5109** connection and in particular must not be a NULL pointer.
5111SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
5114** CAPI3REF: Commit And Rollback Notification Callbacks
5116** ^The sqlite3_commit_hook() interface registers a callback
5117** function to be invoked whenever a transaction is [COMMIT | committed].
5118** ^Any callback set by a previous call to sqlite3_commit_hook()
5119** for the same database connection is overridden.
5120** ^The sqlite3_rollback_hook() interface registers a callback
5121** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
5122** ^Any callback set by a previous call to sqlite3_rollback_hook()
5123** for the same database connection is overridden.
5124** ^The pArg argument is passed through to the callback.
5125** ^If the callback on a commit hook function returns non-zero,
5126** then the commit is converted into a rollback.
5128** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
5129** return the P argument from the previous call of the same function
5130** on the same [database connection] D, or NULL for
5131** the first call for each function on D.
5133** The commit and rollback hook callbacks are not reentrant.
5134** The callback implementation must not do anything that will modify
5135** the database connection that invoked the callback.  Any actions
5136** to modify the database connection must be deferred until after the
5137** completion of the [sqlite3_step()] call that triggered the commit
5138** or rollback hook in the first place.
5139** Note that running any other SQL statements, including SELECT statements,
5140** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
5141** the database connections for the meaning of "modify" in this paragraph.
5143** ^Registering a NULL function disables the callback.
5145** ^When the commit hook callback routine returns zero, the [COMMIT]
5146** operation is allowed to continue normally.  ^If the commit hook
5147** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
5148** ^The rollback hook is invoked on a rollback that results from a commit
5149** hook returning non-zero, just as it would be with any other rollback.
5151** ^For the purposes of this API, a transaction is said to have been
5152** rolled back if an explicit "ROLLBACK" statement is executed, or
5153** an error or constraint causes an implicit rollback to occur.
5154** ^The rollback callback is not invoked if a transaction is
5155** automatically rolled back because the database connection is closed.
5157** See also the [sqlite3_update_hook()] interface.
5159SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
5160SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
5163** CAPI3REF: Data Change Notification Callbacks
5165** ^The sqlite3_update_hook() interface registers a callback function
5166** with the [database connection] identified by the first argument
5167** to be invoked whenever a row is updated, inserted or deleted in
5168** a rowid table.
5169** ^Any callback set by a previous call to this function
5170** for the same database connection is overridden.
5172** ^The second argument is a pointer to the function to invoke when a
5173** row is updated, inserted or deleted in a rowid table.
5174** ^The first argument to the callback is a copy of the third argument
5175** to sqlite3_update_hook().
5176** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
5177** or [SQLITE_UPDATE], depending on the operation that caused the callback
5178** to be invoked.
5179** ^The third and fourth arguments to the callback contain pointers to the
5180** database and table name containing the affected row.
5181** ^The final callback parameter is the [rowid] of the row.
5182** ^In the case of an update, this is the [rowid] after the update takes place.
5184** ^(The update hook is not invoked when internal system tables are
5185** modified (i.e. sqlite_master and sqlite_sequence).)^
5186** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
5188** ^In the current implementation, the update hook
5189** is not invoked when duplication rows are deleted because of an
5190** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
5191** invoked when rows are deleted using the [truncate optimization].
5192** The exceptions defined in this paragraph might change in a future
5193** release of SQLite.
5195** The update hook implementation must not do anything that will modify
5196** the database connection that invoked the update hook.  Any actions
5197** to modify the database connection must be deferred until after the
5198** completion of the [sqlite3_step()] call that triggered the update hook.
5199** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
5200** database connections for the meaning of "modify" in this paragraph.
5202** ^The sqlite3_update_hook(D,C,P) function
5203** returns the P argument from the previous call
5204** on the same [database connection] D, or NULL for
5205** the first call on D.
5207** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
5208** interfaces.
5210SQLITE_API void *sqlite3_update_hook(
5211  sqlite3*,
5212  void(*)(void *,int ,char const *,char const *,sqlite3_int64),
5213  void*
5217** CAPI3REF: Enable Or Disable Shared Pager Cache
5219** ^(This routine enables or disables the sharing of the database cache
5220** and schema data structures between [database connection | connections]
5221** to the same database. Sharing is enabled if the argument is true
5222** and disabled if the argument is false.)^
5224** ^Cache sharing is enabled and disabled for an entire process.
5225** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
5226** sharing was enabled or disabled for each thread separately.
5228** ^(The cache sharing mode set by this interface effects all subsequent
5229** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
5230** Existing database connections continue use the sharing mode
5231** that was in effect at the time they were opened.)^
5233** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
5234** successfully.  An [error code] is returned otherwise.)^
5236** ^Shared cache is disabled by default. But this might change in
5237** future releases of SQLite.  Applications that care about shared
5238** cache setting should set it explicitly.
5240** This interface is threadsafe on processors where writing a
5241** 32-bit integer is atomic.
5243** See Also:  [SQLite Shared-Cache Mode]
5245SQLITE_API int sqlite3_enable_shared_cache(int);
5248** CAPI3REF: Attempt To Free Heap Memory
5250** ^The sqlite3_release_memory() interface attempts to free N bytes
5251** of heap memory by deallocating non-essential memory allocations
5252** held by the database library.   Memory used to cache database
5253** pages to improve performance is an example of non-essential memory.
5254** ^sqlite3_release_memory() returns the number of bytes actually freed,
5255** which might be more or less than the amount requested.
5256** ^The sqlite3_release_memory() routine is a no-op returning zero
5257** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5259** See also: [sqlite3_db_release_memory()]
5261SQLITE_API int sqlite3_release_memory(int);
5264** CAPI3REF: Free Memory Used By A Database Connection
5266** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
5267** memory as possible from database connection D. Unlike the
5268** [sqlite3_release_memory()] interface, this interface is in effect even
5269** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
5270** omitted.
5272** See also: [sqlite3_release_memory()]
5274SQLITE_API int sqlite3_db_release_memory(sqlite3*);
5277** CAPI3REF: Impose A Limit On Heap Size
5279** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
5280** soft limit on the amount of heap memory that may be allocated by SQLite.
5281** ^SQLite strives to keep heap memory utilization below the soft heap
5282** limit by reducing the number of pages held in the page cache
5283** as heap memory usages approaches the limit.
5284** ^The soft heap limit is "soft" because even though SQLite strives to stay
5285** below the limit, it will exceed the limit rather than generate
5286** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
5287** is advisory only.
5289** ^The return value from sqlite3_soft_heap_limit64() is the size of
5290** the soft heap limit prior to the call, or negative in the case of an
5291** error.  ^If the argument N is negative
5292** then no change is made to the soft heap limit.  Hence, the current
5293** size of the soft heap limit can be determined by invoking
5294** sqlite3_soft_heap_limit64() with a negative argument.
5296** ^If the argument N is zero then the soft heap limit is disabled.
5298** ^(The soft heap limit is not enforced in the current implementation
5299** if one or more of following conditions are true:
5301** <ul>
5302** <li> The soft heap limit is set to zero.
5303** <li> Memory accounting is disabled using a combination of the
5304**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
5305**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
5306** <li> An alternative page cache implementation is specified using
5307**      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
5308** <li> The page cache allocates from its own memory pool supplied
5309**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
5310**      from the heap.
5311** </ul>)^
5313** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
5314** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
5315** compile-time option is invoked.  With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
5316** the soft heap limit is enforced on every memory allocation.  Without
5317** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
5318** when memory is allocated by the page cache.  Testing suggests that because
5319** the page cache is the predominate memory user in SQLite, most
5320** applications will achieve adequate soft heap limit enforcement without
5323** The circumstances under which SQLite will enforce the soft heap limit may
5324** changes in future releases of SQLite.
5326SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
5329** CAPI3REF: Deprecated Soft Heap Limit Interface
5332** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
5333** interface.  This routine is provided for historical compatibility
5334** only.  All new applications should use the
5335** [sqlite3_soft_heap_limit64()] interface rather than this one.
5337SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
5341** CAPI3REF: Extract Metadata About A Column Of A Table
5343** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
5344** information about column C of table T in database D
5345** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
5346** interface returns SQLITE_OK and fills in the non-NULL pointers in
5347** the final five arguments with appropriate values if the specified
5348** column exists.  ^The sqlite3_table_column_metadata() interface returns
5349** SQLITE_ERROR and if the specified column does not exist.
5350** ^If the column-name parameter to sqlite3_table_column_metadata() is a
5351** NULL pointer, then this routine simply checks for the existance of the
5352** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
5353** does not.
5355** ^The column is identified by the second, third and fourth parameters to
5356** this function. ^(The second parameter is either the name of the database
5357** (i.e. "main", "temp", or an attached database) containing the specified
5358** table or NULL.)^ ^If it is NULL, then all attached databases are searched
5359** for the table using the same algorithm used by the database engine to
5360** resolve unqualified table references.
5362** ^The third and fourth parameters to this function are the table and column
5363** name of the desired column, respectively.
5365** ^Metadata is returned by writing to the memory locations passed as the 5th
5366** and subsequent parameters to this function. ^Any of these arguments may be
5367** NULL, in which case the corresponding element of metadata is omitted.
5369** ^(<blockquote>
5370** <table border="1">
5371** <tr><th> Parameter <th> Output<br>Type <th>  Description
5373** <tr><td> 5th <td> const char* <td> Data type
5374** <tr><td> 6th <td> const char* <td> Name of default collation sequence
5375** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
5376** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
5377** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
5378** </table>
5379** </blockquote>)^
5381** ^The memory pointed to by the character pointers returned for the
5382** declaration type and collation sequence is valid until the next
5383** call to any SQLite API function.
5385** ^If the specified table is actually a view, an [error code] is returned.
5387** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
5388** is not a [WITHOUT ROWID] table and an
5389** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
5390** parameters are set for the explicitly declared column. ^(If there is no
5391** [INTEGER PRIMARY KEY] column, then the outputs
5392** for the [rowid] are set as follows:
5394** <pre>
5395**     data type: "INTEGER"
5396**     collation sequence: "BINARY"
5397**     not null: 0
5398**     primary key: 1
5399**     auto increment: 0
5400** </pre>)^
5402** ^This function causes all database schemas to be read from disk and
5403** parsed, if that has not already been done, and returns an error if
5404** any errors are encountered while loading the schema.
5406SQLITE_API int sqlite3_table_column_metadata(
5407  sqlite3 *db,                /* Connection handle */
5408  const char *zDbName,        /* Database name or NULL */
5409  const char *zTableName,     /* Table name */
5410  const char *zColumnName,    /* Column name */
5411  char const **pzDataType,    /* OUTPUT: Declared data type */
5412  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
5413  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
5414  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
5415  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
5419** CAPI3REF: Load An Extension
5421** ^This interface loads an SQLite extension library from the named file.
5423** ^The sqlite3_load_extension() interface attempts to load an
5424** [SQLite extension] library contained in the file zFile.  If
5425** the file cannot be loaded directly, attempts are made to load
5426** with various operating-system specific extensions added.
5427** So for example, if "samplelib" cannot be loaded, then names like
5428** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
5429** be tried also.
5431** ^The entry point is zProc.
5432** ^(zProc may be 0, in which case SQLite will try to come up with an
5433** entry point name on its own.  It first tries "sqlite3_extension_init".
5434** If that does not work, it constructs a name "sqlite3_X_init" where the
5435** X is consists of the lower-case equivalent of all ASCII alphabetic
5436** characters in the filename from the last "/" to the first following
5437** "." and omitting any initial "lib".)^
5438** ^The sqlite3_load_extension() interface returns
5439** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
5440** ^If an error occurs and pzErrMsg is not 0, then the
5441** [sqlite3_load_extension()] interface shall attempt to
5442** fill *pzErrMsg with error message text stored in memory
5443** obtained from [sqlite3_malloc()]. The calling function
5444** should free this memory by calling [sqlite3_free()].
5446** ^Extension loading must be enabled using
5447** [sqlite3_enable_load_extension()] prior to calling this API,
5448** otherwise an error will be returned.
5450** See also the [load_extension() SQL function].
5452SQLITE_API int sqlite3_load_extension(
5453  sqlite3 *db,          /* Load the extension into this database connection */
5454  const char *zFile,    /* Name of the shared library containing extension */
5455  const char *zProc,    /* Entry point.  Derived from zFile if 0 */
5456  char **pzErrMsg       /* Put error message here if not 0 */
5460** CAPI3REF: Enable Or Disable Extension Loading
5462** ^So as not to open security holes in older applications that are
5463** unprepared to deal with [extension loading], and as a means of disabling
5464** [extension loading] while evaluating user-entered SQL, the following API
5465** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5467** ^Extension loading is off by default.
5468** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5469** to turn extension loading on and call it with onoff==0 to turn
5470** it back off again.
5472SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
5475** CAPI3REF: Automatically Load Statically Linked Extensions
5477** ^This interface causes the xEntryPoint() function to be invoked for
5478** each new [database connection] that is created.  The idea here is that
5479** xEntryPoint() is the entry point for a statically linked [SQLite extension]
5480** that is to be automatically loaded into all new database connections.
5482** ^(Even though the function prototype shows that xEntryPoint() takes
5483** no arguments and returns void, SQLite invokes xEntryPoint() with three
5484** arguments and expects and integer result as if the signature of the
5485** entry point where as follows:
5487** <blockquote><pre>
5488** &nbsp;  int xEntryPoint(
5489** &nbsp;    sqlite3 *db,
5490** &nbsp;    const char **pzErrMsg,
5491** &nbsp;    const struct sqlite3_api_routines *pThunk
5492** &nbsp;  );
5493** </pre></blockquote>)^
5495** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
5496** point to an appropriate error message (obtained from [sqlite3_mprintf()])
5497** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
5498** is NULL before calling the xEntryPoint().  ^SQLite will invoke
5499** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
5500** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
5501** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
5503** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
5504** on the list of automatic extensions is a harmless no-op. ^No entry point
5505** will be called more than once for each database connection that is opened.
5507** See also: [sqlite3_reset_auto_extension()]
5508** and [sqlite3_cancel_auto_extension()]
5510SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void));
5513** CAPI3REF: Cancel Automatic Extension Loading
5515** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
5516** initialization routine X that was registered using a prior call to
5517** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
5518** routine returns 1 if initialization routine X was successfully
5519** unregistered and it returns 0 if X was not on the list of initialization
5520** routines.
5522SQLITE_API int sqlite3_cancel_auto_extension(void (*xEntryPoint)(void));
5525** CAPI3REF: Reset Automatic Extension Loading
5527** ^This interface disables all automatic extensions previously
5528** registered using [sqlite3_auto_extension()].
5530SQLITE_API void sqlite3_reset_auto_extension(void);
5533** The interface to the virtual-table mechanism is currently considered
5534** to be experimental.  The interface might change in incompatible ways.
5535** If this is a problem for you, do not use the interface at this time.
5537** When the virtual-table mechanism stabilizes, we will declare the
5538** interface fixed, support it indefinitely, and remove this comment.
5542** Structures used by the virtual table interface
5544typedef struct sqlite3_vtab sqlite3_vtab;
5545typedef struct sqlite3_index_info sqlite3_index_info;
5546typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
5547typedef struct sqlite3_module sqlite3_module;
5550** CAPI3REF: Virtual Table Object
5551** KEYWORDS: sqlite3_module {virtual table module}
5553** This structure, sometimes called a "virtual table module",
5554** defines the implementation of a [virtual tables].
5555** This structure consists mostly of methods for the module.
5557** ^A virtual table module is created by filling in a persistent
5558** instance of this structure and passing a pointer to that instance
5559** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
5560** ^The registration remains valid until it is replaced by a different
5561** module or until the [database connection] closes.  The content
5562** of this structure must not change while it is registered with
5563** any database connection.
5565struct sqlite3_module {
5566  int iVersion;
5567  int (*xCreate)(sqlite3*, void *pAux,
5568               int argc, const char *const*argv,
5569               sqlite3_vtab **ppVTab, char**);
5570  int (*xConnect)(sqlite3*, void *pAux,
5571               int argc, const char *const*argv,
5572               sqlite3_vtab **ppVTab, char**);
5573  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
5574  int (*xDisconnect)(sqlite3_vtab *pVTab);
5575  int (*xDestroy)(sqlite3_vtab *pVTab);
5576  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
5577  int (*xClose)(sqlite3_vtab_cursor*);
5578  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
5579                int argc, sqlite3_value **argv);
5580  int (*xNext)(sqlite3_vtab_cursor*);
5581  int (*xEof)(sqlite3_vtab_cursor*);
5582  int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
5583  int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
5584  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
5585  int (*xBegin)(sqlite3_vtab *pVTab);
5586  int (*xSync)(sqlite3_vtab *pVTab);
5587  int (*xCommit)(sqlite3_vtab *pVTab);
5588  int (*xRollback)(sqlite3_vtab *pVTab);
5589  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
5590                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
5591                       void **ppArg);
5592  int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
5593  /* The methods above are in version 1 of the sqlite_module object. Those
5594  ** below are for version 2 and greater. */
5595  int (*xSavepoint)(sqlite3_vtab *pVTab, int);
5596  int (*xRelease)(sqlite3_vtab *pVTab, int);
5597  int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
5601** CAPI3REF: Virtual Table Indexing Information
5602** KEYWORDS: sqlite3_index_info
5604** The sqlite3_index_info structure and its substructures is used as part
5605** of the [virtual table] interface to
5606** pass information into and receive the reply from the [xBestIndex]
5607** method of a [virtual table module].  The fields under **Inputs** are the
5608** inputs to xBestIndex and are read-only.  xBestIndex inserts its
5609** results into the **Outputs** fields.
5611** ^(The aConstraint[] array records WHERE clause constraints of the form:
5613** <blockquote>column OP expr</blockquote>
5615** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
5616** stored in aConstraint[].op using one of the
5618** ^(The index of the column is stored in
5619** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
5620** expr on the right-hand side can be evaluated (and thus the constraint
5621** is usable) and false if it cannot.)^
5623** ^The optimizer automatically inverts terms of the form "expr OP column"
5624** and makes other simplifications to the WHERE clause in an attempt to
5625** get as many WHERE clause terms into the form shown above as possible.
5626** ^The aConstraint[] array only reports WHERE clause terms that are
5627** relevant to the particular virtual table being queried.
5629** ^Information about the ORDER BY clause is stored in aOrderBy[].
5630** ^Each term of aOrderBy records a column of the ORDER BY clause.
5632** The [xBestIndex] method must fill aConstraintUsage[] with information
5633** about what parameters to pass to xFilter.  ^If argvIndex>0 then
5634** the right-hand side of the corresponding aConstraint[] is evaluated
5635** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
5636** is true, then the constraint is assumed to be fully handled by the
5637** virtual table and is not checked again by SQLite.)^
5639** ^The idxNum and idxPtr values are recorded and passed into the
5640** [xFilter] method.
5641** ^[sqlite3_free()] is used to free idxPtr if and only if
5642** needToFreeIdxPtr is true.
5644** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
5645** the correct order to satisfy the ORDER BY clause so that no separate
5646** sorting step is required.
5648** ^The estimatedCost value is an estimate of the cost of a particular
5649** strategy. A cost of N indicates that the cost of the strategy is similar
5650** to a linear scan of an SQLite table with N rows. A cost of log(N)
5651** indicates that the expense of the operation is similar to that of a
5652** binary search on a unique indexed field of an SQLite table with N rows.
5654** ^The estimatedRows value is an estimate of the number of rows that
5655** will be returned by the strategy.
5657** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
5658** structure for SQLite version 3.8.2. If a virtual table extension is
5659** used with an SQLite version earlier than 3.8.2, the results of attempting
5660** to read or write the estimatedRows field are undefined (but are likely
5661** to included crashing the application). The estimatedRows field should
5662** therefore only be used if [sqlite3_libversion_number()] returns a
5663** value greater than or equal to 3008002.
5665struct sqlite3_index_info {
5666  /* Inputs */
5667  int nConstraint;           /* Number of entries in aConstraint */
5668  struct sqlite3_index_constraint {
5669     int iColumn;              /* Column on left-hand side of constraint */
5670     unsigned char op;         /* Constraint operator */
5671     unsigned char usable;     /* True if this constraint is usable */
5672     int iTermOffset;          /* Used internally - xBestIndex should ignore */
5673  } *aConstraint;            /* Table of WHERE clause constraints */
5674  int nOrderBy;              /* Number of terms in the ORDER BY clause */
5675  struct sqlite3_index_orderby {
5676     int iColumn;              /* Column number */
5677     unsigned char desc;       /* True for DESC.  False for ASC. */
5678  } *aOrderBy;               /* The ORDER BY clause */
5679  /* Outputs */
5680  struct sqlite3_index_constraint_usage {
5681    int argvIndex;           /* if >0, constraint is part of argv to xFilter */
5682    unsigned char omit;      /* Do not code a test for this constraint */
5683  } *aConstraintUsage;
5684  int idxNum;                /* Number used to identify the index */
5685  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
5686  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
5687  int orderByConsumed;       /* True if output is already ordered */
5688  double estimatedCost;           /* Estimated cost of using this index */
5689  /* Fields below are only available in SQLite 3.8.2 and later */
5690  sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
5694** CAPI3REF: Virtual Table Constraint Operator Codes
5696** These macros defined the allowed values for the
5697** [sqlite3_index_info].aConstraint[].op field.  Each value represents
5698** an operator that is part of a constraint term in the wHERE clause of
5699** a query that uses a [virtual table].
5709** CAPI3REF: Register A Virtual Table Implementation
5711** ^These routines are used to register a new [virtual table module] name.
5712** ^Module names must be registered before
5713** creating a new [virtual table] using the module and before using a
5714** preexisting [virtual table] for the module.
5716** ^The module name is registered on the [database connection] specified
5717** by the first parameter.  ^The name of the module is given by the
5718** second parameter.  ^The third parameter is a pointer to
5719** the implementation of the [virtual table module].   ^The fourth
5720** parameter is an arbitrary client data pointer that is passed through
5721** into the [xCreate] and [xConnect] methods of the virtual table module
5722** when a new virtual table is be being created or reinitialized.
5724** ^The sqlite3_create_module_v2() interface has a fifth parameter which
5725** is a pointer to a destructor for the pClientData.  ^SQLite will
5726** invoke the destructor function (if it is not NULL) when SQLite
5727** no longer needs the pClientData pointer.  ^The destructor will also
5728** be invoked if the call to sqlite3_create_module_v2() fails.
5729** ^The sqlite3_create_module()
5730** interface is equivalent to sqlite3_create_module_v2() with a NULL
5731** destructor.
5733SQLITE_API int sqlite3_create_module(
5734  sqlite3 *db,               /* SQLite connection to register module with */
5735  const char *zName,         /* Name of the module */
5736  const sqlite3_module *p,   /* Methods for the module */
5737  void *pClientData          /* Client data for xCreate/xConnect */
5739SQLITE_API int sqlite3_create_module_v2(
5740  sqlite3 *db,               /* SQLite connection to register module with */
5741  const char *zName,         /* Name of the module */
5742  const sqlite3_module *p,   /* Methods for the module */
5743  void *pClientData,         /* Client data for xCreate/xConnect */
5744  void(*xDestroy)(void*)     /* Module destructor function */
5748** CAPI3REF: Virtual Table Instance Object
5749** KEYWORDS: sqlite3_vtab
5751** Every [virtual table module] implementation uses a subclass
5752** of this object to describe a particular instance
5753** of the [virtual table].  Each subclass will
5754** be tailored to the specific needs of the module implementation.
5755** The purpose of this superclass is to define certain fields that are
5756** common to all module implementations.
5758** ^Virtual tables methods can set an error message by assigning a
5759** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
5760** take care that any prior string is freed by a call to [sqlite3_free()]
5761** prior to assigning a new string to zErrMsg.  ^After the error message
5762** is delivered up to the client application, the string will be automatically
5763** freed by sqlite3_free() and the zErrMsg field will be zeroed.
5765struct sqlite3_vtab {
5766  const sqlite3_module *pModule;  /* The module for this virtual table */
5767  int nRef;                       /* NO LONGER USED */
5768  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
5769  /* Virtual table implementations will typically add additional fields */
5773** CAPI3REF: Virtual Table Cursor Object
5774** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
5776** Every [virtual table module] implementation uses a subclass of the
5777** following structure to describe cursors that point into the
5778** [virtual table] and are used
5779** to loop through the virtual table.  Cursors are created using the
5780** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
5781** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
5782** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
5783** of the module.  Each module implementation will define
5784** the content of a cursor structure to suit its own needs.
5786** This superclass exists in order to define fields of the cursor that
5787** are common to all implementations.
5789struct sqlite3_vtab_cursor {
5790  sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
5791  /* Virtual table implementations will typically add additional fields */
5795** CAPI3REF: Declare The Schema Of A Virtual Table
5797** ^The [xCreate] and [xConnect] methods of a
5798** [virtual table module] call this interface
5799** to declare the format (the names and datatypes of the columns) of
5800** the virtual tables they implement.
5802SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
5805** CAPI3REF: Overload A Function For A Virtual Table
5807** ^(Virtual tables can provide alternative implementations of functions
5808** using the [xFindFunction] method of the [virtual table module].
5809** But global versions of those functions
5810** must exist in order to be overloaded.)^
5812** ^(This API makes sure a global version of a function with a particular
5813** name and number of parameters exists.  If no such function exists
5814** before this API is called, a new function is created.)^  ^The implementation
5815** of the new function always causes an exception to be thrown.  So
5816** the new function is not good for anything by itself.  Its only
5817** purpose is to be a placeholder function that can be overloaded
5818** by a [virtual table].
5820SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
5823** The interface to the virtual-table mechanism defined above (back up
5824** to a comment remarkably similar to this one) is currently considered
5825** to be experimental.  The interface might change in incompatible ways.
5826** If this is a problem for you, do not use the interface at this time.
5828** When the virtual-table mechanism stabilizes, we will declare the
5829** interface fixed, support it indefinitely, and remove this comment.
5833** CAPI3REF: A Handle To An Open BLOB
5834** KEYWORDS: {BLOB handle} {BLOB handles}
5836** An instance of this object represents an open BLOB on which
5837** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
5838** ^Objects of this type are created by [sqlite3_blob_open()]
5839** and destroyed by [sqlite3_blob_close()].
5840** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
5841** can be used to read or write small subsections of the BLOB.
5842** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
5844typedef struct sqlite3_blob sqlite3_blob;
5847** CAPI3REF: Open A BLOB For Incremental I/O
5849** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
5850** in row iRow, column zColumn, table zTable in database zDb;
5851** in other words, the same BLOB that would be selected by:
5853** <pre>
5854**     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
5855** </pre>)^
5857** ^(Parameter zDb is not the filename that contains the database, but
5858** rather the symbolic name of the database. For attached databases, this is
5859** the name that appears after the AS keyword in the [ATTACH] statement.
5860** For the main database file, the database name is "main". For TEMP
5861** tables, the database name is "temp".)^
5863** ^If the flags parameter is non-zero, then the BLOB is opened for read
5864** and write access. ^If the flags parameter is zero, the BLOB is opened for
5865** read-only access.
5867** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
5868** in *ppBlob. Otherwise an [error code] is returned and, unless the error
5869** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
5870** the API is not misused, it is always safe to call [sqlite3_blob_close()]
5871** on *ppBlob after this function it returns.
5873** This function fails with SQLITE_ERROR if any of the following are true:
5874** <ul>
5875**   <li> ^(Database zDb does not exist)^,
5876**   <li> ^(Table zTable does not exist within database zDb)^,
5877**   <li> ^(Table zTable is a WITHOUT ROWID table)^,
5878**   <li> ^(Column zColumn does not exist)^,
5879**   <li> ^(Row iRow is not present in the table)^,
5880**   <li> ^(The specified column of row iRow contains a value that is not
5881**         a TEXT or BLOB value)^,
5882**   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
5883**         constraint and the blob is being opened for read/write access)^,
5884**   <li> ^([foreign key constraints | Foreign key constraints] are enabled,
5885**         column zColumn is part of a [child key] definition and the blob is
5886**         being opened for read/write access)^.
5887** </ul>
5889** ^Unless it returns SQLITE_MISUSE, this function sets the
5890** [database connection] error code and message accessible via
5891** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
5894** ^(If the row that a BLOB handle points to is modified by an
5895** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
5896** then the BLOB handle is marked as "expired".
5897** This is true if any column of the row is changed, even a column
5898** other than the one the BLOB handle is open on.)^
5899** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
5900** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
5901** ^(Changes written into a BLOB prior to the BLOB expiring are not
5902** rolled back by the expiration of the BLOB.  Such changes will eventually
5903** commit if the transaction continues to completion.)^
5905** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
5906** the opened blob.  ^The size of a blob may not be changed by this
5907** interface.  Use the [UPDATE] SQL command to change the size of a
5908** blob.
5910** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
5911** and the built-in [zeroblob] SQL function may be used to create a
5912** zero-filled blob to read or write using the incremental-blob interface.
5914** To avoid a resource leak, every open [BLOB handle] should eventually
5915** be released by a call to [sqlite3_blob_close()].
5917SQLITE_API int sqlite3_blob_open(
5918  sqlite3*,
5919  const char *zDb,
5920  const char *zTable,
5921  const char *zColumn,
5922  sqlite3_int64 iRow,
5923  int flags,
5924  sqlite3_blob **ppBlob
5928** CAPI3REF: Move a BLOB Handle to a New Row
5930** ^This function is used to move an existing blob handle so that it points
5931** to a different row of the same database table. ^The new row is identified
5932** by the rowid value passed as the second argument. Only the row can be
5933** changed. ^The database, table and column on which the blob handle is open
5934** remain the same. Moving an existing blob handle to a new row can be
5935** faster than closing the existing handle and opening a new one.
5937** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
5938** it must exist and there must be either a blob or text value stored in
5939** the nominated column.)^ ^If the new row is not present in the table, or if
5940** it does not contain a blob or text value, or if another error occurs, an
5941** SQLite error code is returned and the blob handle is considered aborted.
5942** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
5943** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
5944** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
5945** always returns zero.
5947** ^This function sets the database handle error code and message.
5949SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
5952** CAPI3REF: Close A BLOB Handle
5954** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
5955** unconditionally.  Even if this routine returns an error code, the
5956** handle is still closed.)^
5958** ^If the blob handle being closed was opened for read-write access, and if
5959** the database is in auto-commit mode and there are no other open read-write
5960** blob handles or active write statements, the current transaction is
5961** committed. ^If an error occurs while committing the transaction, an error
5962** code is returned and the transaction rolled back.
5964** Calling this function with an argument that is not a NULL pointer or an
5965** open blob handle results in undefined behaviour. ^Calling this routine
5966** with a null pointer (such as would be returned by a failed call to
5967** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
5968** is passed a valid open blob handle, the values returned by the
5969** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
5971SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
5974** CAPI3REF: Return The Size Of An Open BLOB
5976** ^Returns the size in bytes of the BLOB accessible via the
5977** successfully opened [BLOB handle] in its only argument.  ^The
5978** incremental blob I/O routines can only read or overwriting existing
5979** blob content; they cannot change the size of a blob.
5981** This routine only works on a [BLOB handle] which has been created
5982** by a prior successful call to [sqlite3_blob_open()] and which has not
5983** been closed by [sqlite3_blob_close()].  Passing any other pointer in
5984** to this routine results in undefined and probably undesirable behavior.
5986SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
5989** CAPI3REF: Read Data From A BLOB Incrementally
5991** ^(This function is used to read data from an open [BLOB handle] into a
5992** caller-supplied buffer. N bytes of data are copied into buffer Z
5993** from the open BLOB, starting at offset iOffset.)^
5995** ^If offset iOffset is less than N bytes from the end of the BLOB,
5996** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
5997** less than zero, [SQLITE_ERROR] is returned and no data is read.
5998** ^The size of the blob (and hence the maximum value of N+iOffset)
5999** can be determined using the [sqlite3_blob_bytes()] interface.
6001** ^An attempt to read from an expired [BLOB handle] fails with an
6002** error code of [SQLITE_ABORT].
6004** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
6005** Otherwise, an [error code] or an [extended error code] is returned.)^
6007** This routine only works on a [BLOB handle] which has been created
6008** by a prior successful call to [sqlite3_blob_open()] and which has not
6009** been closed by [sqlite3_blob_close()].  Passing any other pointer in
6010** to this routine results in undefined and probably undesirable behavior.
6012** See also: [sqlite3_blob_write()].
6014SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
6017** CAPI3REF: Write Data Into A BLOB Incrementally
6019** ^(This function is used to write data into an open [BLOB handle] from a
6020** caller-supplied buffer. N bytes of data are copied from the buffer Z
6021** into the open BLOB, starting at offset iOffset.)^
6023** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
6024** Otherwise, an  [error code] or an [extended error code] is returned.)^
6025** ^Unless SQLITE_MISUSE is returned, this function sets the
6026** [database connection] error code and message accessible via
6027** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6029** ^If the [BLOB handle] passed as the first argument was not opened for
6030** writing (the flags parameter to [sqlite3_blob_open()] was zero),
6031** this function returns [SQLITE_READONLY].
6033** This function may only modify the contents of the BLOB; it is
6034** not possible to increase the size of a BLOB using this API.
6035** ^If offset iOffset is less than N bytes from the end of the BLOB,
6036** [SQLITE_ERROR] is returned and no data is written. The size of the
6037** BLOB (and hence the maximum value of N+iOffset) can be determined
6038** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
6039** than zero [SQLITE_ERROR] is returned and no data is written.
6041** ^An attempt to write to an expired [BLOB handle] fails with an
6042** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
6043** before the [BLOB handle] expired are not rolled back by the
6044** expiration of the handle, though of course those changes might
6045** have been overwritten by the statement that expired the BLOB handle
6046** or by other independent statements.
6048** This routine only works on a [BLOB handle] which has been created
6049** by a prior successful call to [sqlite3_blob_open()] and which has not
6050** been closed by [sqlite3_blob_close()].  Passing any other pointer in
6051** to this routine results in undefined and probably undesirable behavior.
6053** See also: [sqlite3_blob_read()].
6055SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
6058** CAPI3REF: Virtual File System Objects
6060** A virtual filesystem (VFS) is an [sqlite3_vfs] object
6061** that SQLite uses to interact
6062** with the underlying operating system.  Most SQLite builds come with a
6063** single default VFS that is appropriate for the host computer.
6064** New VFSes can be registered and existing VFSes can be unregistered.
6065** The following interfaces are provided.
6067** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
6068** ^Names are case sensitive.
6069** ^Names are zero-terminated UTF-8 strings.
6070** ^If there is no match, a NULL pointer is returned.
6071** ^If zVfsName is NULL then the default VFS is returned.
6073** ^New VFSes are registered with sqlite3_vfs_register().
6074** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
6075** ^The same VFS can be registered multiple times without injury.
6076** ^To make an existing VFS into the default VFS, register it again
6077** with the makeDflt flag set.  If two different VFSes with the
6078** same name are registered, the behavior is undefined.  If a
6079** VFS is registered with a name that is NULL or an empty string,
6080** then the behavior is undefined.
6082** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
6083** ^(If the default VFS is unregistered, another VFS is chosen as
6084** the default.  The choice for the new VFS is arbitrary.)^
6086SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
6087SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
6088SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
6091** CAPI3REF: Mutexes
6093** The SQLite core uses these routines for thread
6094** synchronization. Though they are intended for internal
6095** use by SQLite, code that links against SQLite is
6096** permitted to use any of these routines.
6098** The SQLite source code contains multiple implementations
6099** of these mutex routines.  An appropriate implementation
6100** is selected automatically at compile-time.  The following
6101** implementations are available in the SQLite core:
6103** <ul>
6105** <li>   SQLITE_MUTEX_W32
6106** <li>   SQLITE_MUTEX_NOOP
6107** </ul>
6109** The SQLITE_MUTEX_NOOP implementation is a set of routines
6110** that does no real locking and is appropriate for use in
6111** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
6112** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
6113** and Windows.
6115** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
6116** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
6117** implementation is included with the library. In this case the
6118** application must supply a custom mutex implementation using the
6119** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
6120** before calling sqlite3_initialize() or any other public sqlite3_
6121** function that calls sqlite3_initialize().
6123** ^The sqlite3_mutex_alloc() routine allocates a new
6124** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
6125** routine returns NULL if it is unable to allocate the requested
6126** mutex.  The argument to sqlite3_mutex_alloc() must one of these
6127** integer constants:
6129** <ul>
6130** <li>  SQLITE_MUTEX_FAST
6141** </ul>
6143** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
6144** cause sqlite3_mutex_alloc() to create
6145** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
6146** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
6147** The mutex implementation does not need to make a distinction
6148** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
6149** not want to.  SQLite will only request a recursive mutex in
6150** cases where it really needs one.  If a faster non-recursive mutex
6151** implementation is available on the host platform, the mutex subsystem
6152** might return such a mutex in response to SQLITE_MUTEX_FAST.
6154** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
6156** a pointer to a static preexisting mutex.  ^Nine static mutexes are
6157** used by the current version of SQLite.  Future versions of SQLite
6158** may add additional static mutexes.  Static mutexes are for internal
6159** use by SQLite only.  Applications that use SQLite mutexes should
6160** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
6163** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
6164** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
6165** returns a different mutex on every call.  ^For the static
6166** mutex types, the same mutex is returned on every call that has
6167** the same type number.
6169** ^The sqlite3_mutex_free() routine deallocates a previously
6170** allocated dynamic mutex.  Attempting to deallocate a static
6171** mutex results in undefined behavior.
6173** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
6174** to enter a mutex.  ^If another thread is already within the mutex,
6175** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
6176** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
6177** upon successful entry.  ^(Mutexes created using
6178** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
6179** In such cases, the
6180** mutex must be exited an equal number of times before another thread
6181** can enter.)^  If the same thread tries to enter any mutex other
6182** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
6184** ^(Some systems (for example, Windows 95) do not support the operation
6185** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
6186** will always return SQLITE_BUSY. The SQLite core only ever uses
6187** sqlite3_mutex_try() as an optimization so this is acceptable
6188** behavior.)^
6190** ^The sqlite3_mutex_leave() routine exits a mutex that was
6191** previously entered by the same thread.   The behavior
6192** is undefined if the mutex is not currently entered by the
6193** calling thread or is not currently allocated.
6195** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
6196** sqlite3_mutex_leave() is a NULL pointer, then all three routines
6197** behave as no-ops.
6199** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
6201SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
6202SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
6203SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
6204SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
6205SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
6208** CAPI3REF: Mutex Methods Object
6210** An instance of this structure defines the low-level routines
6211** used to allocate and use mutexes.
6213** Usually, the default mutex implementations provided by SQLite are
6214** sufficient, however the application has the option of substituting a custom
6215** implementation for specialized deployments or systems for which SQLite
6216** does not provide a suitable implementation. In this case, the application
6217** creates and populates an instance of this structure to pass
6218** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
6219** Additionally, an instance of this structure can be used as an
6220** output variable when querying the system for the current mutex
6221** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
6223** ^The xMutexInit method defined by this structure is invoked as
6224** part of system initialization by the sqlite3_initialize() function.
6225** ^The xMutexInit routine is called by SQLite exactly once for each
6226** effective call to [sqlite3_initialize()].
6228** ^The xMutexEnd method defined by this structure is invoked as
6229** part of system shutdown by the sqlite3_shutdown() function. The
6230** implementation of this method is expected to release all outstanding
6231** resources obtained by the mutex methods implementation, especially
6232** those obtained by the xMutexInit method.  ^The xMutexEnd()
6233** interface is invoked exactly once for each call to [sqlite3_shutdown()].
6235** ^(The remaining seven methods defined by this structure (xMutexAlloc,
6236** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
6237** xMutexNotheld) implement the following interfaces (respectively):
6239** <ul>
6240**   <li>  [sqlite3_mutex_alloc()] </li>
6241**   <li>  [sqlite3_mutex_free()] </li>
6242**   <li>  [sqlite3_mutex_enter()] </li>
6243**   <li>  [sqlite3_mutex_try()] </li>
6244**   <li>  [sqlite3_mutex_leave()] </li>
6245**   <li>  [sqlite3_mutex_held()] </li>
6246**   <li>  [sqlite3_mutex_notheld()] </li>
6247** </ul>)^
6249** The only difference is that the public sqlite3_XXX functions enumerated
6250** above silently ignore any invocations that pass a NULL pointer instead
6251** of a valid mutex handle. The implementations of the methods defined
6252** by this structure are not required to handle this case, the results
6253** of passing a NULL pointer instead of a valid mutex handle are undefined
6254** (i.e. it is acceptable to provide an implementation that segfaults if
6255** it is passed a NULL pointer).
6257** The xMutexInit() method must be threadsafe.  It must be harmless to
6258** invoke xMutexInit() multiple times within the same process and without
6259** intervening calls to xMutexEnd().  Second and subsequent calls to
6260** xMutexInit() must be no-ops.
6262** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
6263** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
6264** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
6265** memory allocation for a fast or recursive mutex.
6267** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
6268** called, but only if the prior call to xMutexInit returned SQLITE_OK.
6269** If xMutexInit fails in any way, it is expected to clean up after itself
6270** prior to returning.
6272typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
6273struct sqlite3_mutex_methods {
6274  int (*xMutexInit)(void);
6275  int (*xMutexEnd)(void);
6276  sqlite3_mutex *(*xMutexAlloc)(int);
6277  void (*xMutexFree)(sqlite3_mutex *);
6278  void (*xMutexEnter)(sqlite3_mutex *);
6279  int (*xMutexTry)(sqlite3_mutex *);
6280  void (*xMutexLeave)(sqlite3_mutex *);
6281  int (*xMutexHeld)(sqlite3_mutex *);
6282  int (*xMutexNotheld)(sqlite3_mutex *);
6286** CAPI3REF: Mutex Verification Routines
6288** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
6289** are intended for use inside assert() statements.  The SQLite core
6290** never uses these routines except inside an assert() and applications
6291** are advised to follow the lead of the core.  The SQLite core only
6292** provides implementations for these routines when it is compiled
6293** with the SQLITE_DEBUG flag.  External mutex implementations
6294** are only required to provide these routines if SQLITE_DEBUG is
6295** defined and if NDEBUG is not defined.
6297** These routines should return true if the mutex in their argument
6298** is held or not held, respectively, by the calling thread.
6300** The implementation is not required to provide versions of these
6301** routines that actually work. If the implementation does not provide working
6302** versions of these routines, it should at least provide stubs that always
6303** return true so that one does not get spurious assertion failures.
6305** If the argument to sqlite3_mutex_held() is a NULL pointer then
6306** the routine should return 1.   This seems counter-intuitive since
6307** clearly the mutex cannot be held if it does not exist.  But
6308** the reason the mutex does not exist is because the build is not
6309** using mutexes.  And we do not want the assert() containing the
6310** call to sqlite3_mutex_held() to fail, so a non-zero return is
6311** the appropriate thing to do.  The sqlite3_mutex_notheld()
6312** interface should also return 1 when given a NULL pointer.
6314#ifndef NDEBUG
6315SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
6316SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
6320** CAPI3REF: Mutex Types
6322** The [sqlite3_mutex_alloc()] interface takes a single argument
6323** which is one of these integer constants.
6325** The set of static mutexes may change from one SQLite release to the
6326** next.  Applications that override the built-in mutex logic must be
6327** prepared to accommodate additional static mutexes.
6329#define SQLITE_MUTEX_FAST             0
6330#define SQLITE_MUTEX_RECURSIVE        1
6332#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
6333#define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
6334#define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
6335#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
6336#define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
6337#define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
6338#define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
6339#define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
6340#define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
6341#define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
6344** CAPI3REF: Retrieve the mutex for a database connection
6346** ^This interface returns a pointer the [sqlite3_mutex] object that
6347** serializes access to the [database connection] given in the argument
6348** when the [threading mode] is Serialized.
6349** ^If the [threading mode] is Single-thread or Multi-thread then this
6350** routine returns a NULL pointer.
6352SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
6355** CAPI3REF: Low-Level Control Of Database Files
6357** ^The [sqlite3_file_control()] interface makes a direct call to the
6358** xFileControl method for the [sqlite3_io_methods] object associated
6359** with a particular database identified by the second argument. ^The
6360** name of the database is "main" for the main database or "temp" for the
6361** TEMP database, or the name that appears after the AS keyword for
6362** databases that are added using the [ATTACH] SQL command.
6363** ^A NULL pointer can be used in place of "main" to refer to the
6364** main database file.
6365** ^The third and fourth parameters to this routine
6366** are passed directly through to the second and third parameters of
6367** the xFileControl method.  ^The return value of the xFileControl
6368** method becomes the return value of this routine.
6370** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
6371** a pointer to the underlying [sqlite3_file] object to be written into
6372** the space pointed to by the 4th parameter.  ^The SQLITE_FCNTL_FILE_POINTER
6373** case is a short-circuit path which does not actually invoke the
6374** underlying sqlite3_io_methods.xFileControl method.
6376** ^If the second parameter (zDbName) does not match the name of any
6377** open database file, then SQLITE_ERROR is returned.  ^This error
6378** code is not remembered and will not be recalled by [sqlite3_errcode()]
6379** or [sqlite3_errmsg()].  The underlying xFileControl method might
6380** also return SQLITE_ERROR.  There is no way to distinguish between
6381** an incorrect zDbName and an SQLITE_ERROR return from the underlying
6382** xFileControl method.
6386SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
6389** CAPI3REF: Testing Interface
6391** ^The sqlite3_test_control() interface is used to read out internal
6392** state of SQLite and to inject faults into SQLite for testing
6393** purposes.  ^The first parameter is an operation code that determines
6394** the number, meaning, and operation of all subsequent parameters.
6396** This interface is not for use by applications.  It exists solely
6397** for verifying the correct operation of the SQLite library.  Depending
6398** on how the SQLite library is compiled, this interface might not exist.
6400** The details of the operation codes, their meanings, the parameters
6401** they take, and what they do are all subject to change without notice.
6402** Unlike most of the SQLite API, this function is not guaranteed to
6403** operate consistently from one release to the next.
6405SQLITE_API int sqlite3_test_control(int op, ...);
6408** CAPI3REF: Testing Interface Operation Codes
6410** These constants are the valid operation code parameters used
6411** as the first argument to [sqlite3_test_control()].
6413** These parameters and their meanings are subject to change
6414** without notice.  These values are for testing purposes only.
6415** Applications should not use any of these parameters or the
6416** [sqlite3_test_control()] interface.
6418#define SQLITE_TESTCTRL_FIRST                    5
6419#define SQLITE_TESTCTRL_PRNG_SAVE                5
6420#define SQLITE_TESTCTRL_PRNG_RESTORE             6
6421#define SQLITE_TESTCTRL_PRNG_RESET               7
6422#define SQLITE_TESTCTRL_BITVEC_TEST              8
6423#define SQLITE_TESTCTRL_FAULT_INSTALL            9
6425#define SQLITE_TESTCTRL_PENDING_BYTE            11
6426#define SQLITE_TESTCTRL_ASSERT                  12
6427#define SQLITE_TESTCTRL_ALWAYS                  13
6428#define SQLITE_TESTCTRL_RESERVE                 14
6429#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
6430#define SQLITE_TESTCTRL_ISKEYWORD               16
6431#define SQLITE_TESTCTRL_SCRATCHMALLOC           17
6433#define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
6434#define SQLITE_TESTCTRL_NEVER_CORRUPT           20
6435#define SQLITE_TESTCTRL_VDBE_COVERAGE           21
6436#define SQLITE_TESTCTRL_BYTEORDER               22
6437#define SQLITE_TESTCTRL_ISINIT                  23
6438#define SQLITE_TESTCTRL_SORTER_MMAP             24
6439#define SQLITE_TESTCTRL_LAST                    24
6442** CAPI3REF: SQLite Runtime Status
6444** ^This interface is used to retrieve runtime status information
6445** about the performance of SQLite, and optionally to reset various
6446** highwater marks.  ^The first argument is an integer code for
6447** the specific parameter to measure.  ^(Recognized integer codes
6448** are of the form [status parameters | SQLITE_STATUS_...].)^
6449** ^The current value of the parameter is returned into *pCurrent.
6450** ^The highest recorded value is returned in *pHighwater.  ^If the
6451** resetFlag is true, then the highest record value is reset after
6452** *pHighwater is written.  ^(Some parameters do not record the highest
6453** value.  For those parameters
6454** nothing is written into *pHighwater and the resetFlag is ignored.)^
6455** ^(Other parameters record only the highwater mark and not the current
6456** value.  For these latter parameters nothing is written into *pCurrent.)^
6458** ^The sqlite3_status() routine returns SQLITE_OK on success and a
6459** non-zero [error code] on failure.
6461** This routine is threadsafe but is not atomic.  This routine can be
6462** called while other threads are running the same or different SQLite
6463** interfaces.  However the values returned in *pCurrent and
6464** *pHighwater reflect the status of SQLite at different points in time
6465** and it is possible that another thread might change the parameter
6466** in between the times when *pCurrent and *pHighwater are written.
6468** See also: [sqlite3_db_status()]
6470SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
6474** CAPI3REF: Status Parameters
6475** KEYWORDS: {status parameters}
6477** These integer constants designate various run-time status parameters
6478** that can be returned by [sqlite3_status()].
6480** <dl>
6482** <dd>This parameter is the current amount of memory checked out
6483** using [sqlite3_malloc()], either directly or indirectly.  The
6484** figure includes calls made to [sqlite3_malloc()] by the application
6485** and internal memory usage by the SQLite library.  Scratch memory
6486** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
6487** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
6488** this parameter.  The amount returned is the sum of the allocation
6489** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
6492** <dd>This parameter records the largest memory allocation request
6493** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
6494** internal equivalents).  Only the value returned in the
6495** *pHighwater parameter to [sqlite3_status()] is of interest.
6496** The value written into the *pCurrent parameter is undefined.</dd>)^
6499** <dd>This parameter records the number of separate memory allocations
6500** currently checked out.</dd>)^
6503** <dd>This parameter returns the number of pages used out of the
6504** [pagecache memory allocator] that was configured using
6506** value returned is in pages, not in bytes.</dd>)^
6510** <dd>This parameter returns the number of bytes of page cache
6511** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
6512** buffer and where forced to overflow to [sqlite3_malloc()].  The
6513** returned value includes allocations that overflowed because they
6514** where too large (they were larger than the "sz" parameter to
6515** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
6516** no space was left in the page cache.</dd>)^
6519** <dd>This parameter records the largest memory allocation request
6520** handed to [pagecache memory allocator].  Only the value returned in the
6521** *pHighwater parameter to [sqlite3_status()] is of interest.
6522** The value written into the *pCurrent parameter is undefined.</dd>)^
6525** <dd>This parameter returns the number of allocations used out of the
6526** [scratch memory allocator] configured using
6527** [SQLITE_CONFIG_SCRATCH].  The value returned is in allocations, not
6528** in bytes.  Since a single thread may only have one scratch allocation
6529** outstanding at time, this parameter also reports the number of threads
6530** using scratch memory at the same time.</dd>)^
6533** <dd>This parameter returns the number of bytes of scratch memory
6534** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
6535** buffer and where forced to overflow to [sqlite3_malloc()].  The values
6536** returned include overflows because the requested allocation was too
6537** larger (that is, because the requested allocation was larger than the
6538** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
6539** slots were available.
6540** </dd>)^
6543** <dd>This parameter records the largest memory allocation request
6544** handed to [scratch memory allocator].  Only the value returned in the
6545** *pHighwater parameter to [sqlite3_status()] is of interest.
6546** The value written into the *pCurrent parameter is undefined.</dd>)^
6549** <dd>This parameter records the deepest parser stack.  It is only
6550** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
6551** </dl>
6553** New status parameters may be added from time to time.
6555#define SQLITE_STATUS_MEMORY_USED          0
6558#define SQLITE_STATUS_SCRATCH_USED         3
6560#define SQLITE_STATUS_MALLOC_SIZE          5
6561#define SQLITE_STATUS_PARSER_STACK         6
6563#define SQLITE_STATUS_SCRATCH_SIZE         8
6564#define SQLITE_STATUS_MALLOC_COUNT         9
6567** CAPI3REF: Database Connection Status
6569** ^This interface is used to retrieve runtime status information
6570** about a single [database connection].  ^The first argument is the
6571** database connection object to be interrogated.  ^The second argument
6572** is an integer constant, taken from the set of
6573** [SQLITE_DBSTATUS options], that
6574** determines the parameter to interrogate.  The set of
6575** [SQLITE_DBSTATUS options] is likely
6576** to grow in future releases of SQLite.
6578** ^The current value of the requested parameter is written into *pCur
6579** and the highest instantaneous value is written into *pHiwtr.  ^If
6580** the resetFlg is true, then the highest instantaneous value is
6581** reset back down to the current value.
6583** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
6584** non-zero [error code] on failure.
6586** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
6588SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
6591** CAPI3REF: Status Parameters for database connections
6594** These constants are the available integer "verbs" that can be passed as
6595** the second argument to the [sqlite3_db_status()] interface.
6597** New verbs may be added in future releases of SQLite. Existing verbs
6598** might be discontinued. Applications should check the return code from
6599** [sqlite3_db_status()] to make sure that the call worked.
6600** The [sqlite3_db_status()] interface will return a non-zero error code
6601** if a discontinued or unsupported verb is invoked.
6603** <dl>
6605** <dd>This parameter returns the number of lookaside memory slots currently
6606** checked out.</dd>)^
6609** <dd>This parameter returns the number malloc attempts that were
6610** satisfied using lookaside memory. Only the high-water value is meaningful;
6611** the current value is always zero.)^
6615** <dd>This parameter returns the number malloc attempts that might have
6616** been satisfied using lookaside memory but failed due to the amount of
6617** memory requested being larger than the lookaside slot size.
6618** Only the high-water value is meaningful;
6619** the current value is always zero.)^
6623** <dd>This parameter returns the number malloc attempts that might have
6624** been satisfied using lookaside memory but failed due to all lookaside
6625** memory already being in use.
6626** Only the high-water value is meaningful;
6627** the current value is always zero.)^
6630** <dd>This parameter returns the approximate number of bytes of heap
6631** memory used by all pager caches associated with the database connection.)^
6632** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
6635** <dd>This parameter returns the approximate number of bytes of heap
6636** memory used to store the schema for all databases associated
6637** with the connection - main, temp, and any [ATTACH]-ed databases.)^
6638** ^The full amount of memory used by the schemas is reported, even if the
6639** schema memory is shared with other database connections due to
6640** [shared cache mode] being enabled.
6641** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
6644** <dd>This parameter returns the approximate number of bytes of heap
6645** and lookaside memory used by all prepared statements associated with
6646** the database connection.)^
6647** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
6648** </dd>
6651** <dd>This parameter returns the number of pager cache hits that have
6652** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
6653** is always 0.
6654** </dd>
6657** <dd>This parameter returns the number of pager cache misses that have
6658** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
6659** is always 0.
6660** </dd>
6663** <dd>This parameter returns the number of dirty cache entries that have
6664** been written to disk. Specifically, the number of pages written to the
6665** wal file in wal mode databases, or the number of pages written to the
6666** database file in rollback mode databases. Any pages written as part of
6667** transaction rollback or database recovery operations are not included.
6668** If an IO or other error occurs while writing a page to disk, the effect
6669** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
6670** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
6671** </dd>
6674** <dd>This parameter returns zero for the current value if and only if
6675** all foreign key constraints (deferred or immediate) have been
6676** resolved.)^  ^The highwater mark is always 0.
6677** </dd>
6678** </dl>
6681#define SQLITE_DBSTATUS_CACHE_USED           1
6682#define SQLITE_DBSTATUS_SCHEMA_USED          2
6683#define SQLITE_DBSTATUS_STMT_USED            3
6687#define SQLITE_DBSTATUS_CACHE_HIT            7
6688#define SQLITE_DBSTATUS_CACHE_MISS           8
6689#define SQLITE_DBSTATUS_CACHE_WRITE          9
6690#define SQLITE_DBSTATUS_DEFERRED_FKS        10
6691#define SQLITE_DBSTATUS_MAX                 10   /* Largest defined DBSTATUS */
6695** CAPI3REF: Prepared Statement Status
6697** ^(Each prepared statement maintains various
6698** [SQLITE_STMTSTATUS counters] that measure the number
6699** of times it has performed specific operations.)^  These counters can
6700** be used to monitor the performance characteristics of the prepared
6701** statements.  For example, if the number of table steps greatly exceeds
6702** the number of table searches or result rows, that would tend to indicate
6703** that the prepared statement is using a full table scan rather than
6704** an index.
6706** ^(This interface is used to retrieve and reset counter values from
6707** a [prepared statement].  The first argument is the prepared statement
6708** object to be interrogated.  The second argument
6709** is an integer code for a specific [SQLITE_STMTSTATUS counter]
6710** to be interrogated.)^
6711** ^The current value of the requested counter is returned.
6712** ^If the resetFlg is true, then the counter is reset to zero after this
6713** interface call returns.
6715** See also: [sqlite3_status()] and [sqlite3_db_status()].
6717SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
6720** CAPI3REF: Status Parameters for prepared statements
6723** These preprocessor macros define integer codes that name counter
6724** values associated with the [sqlite3_stmt_status()] interface.
6725** The meanings of the various counters are as follows:
6727** <dl>
6729** <dd>^This is the number of times that SQLite has stepped forward in
6730** a table as part of a full table scan.  Large numbers for this counter
6731** may indicate opportunities for performance improvement through
6732** careful use of indices.</dd>
6735** <dd>^This is the number of sort operations that have occurred.
6736** A non-zero value in this counter may indicate an opportunity to
6737** improvement performance through careful use of indices.</dd>
6740** <dd>^This is the number of rows inserted into transient indices that
6741** were created automatically in order to help joins run faster.
6742** A non-zero value in this counter may indicate an opportunity to
6743** improvement performance by adding permanent indices that do not
6744** need to be reinitialized each time the statement is run.</dd>
6747** <dd>^This is the number of virtual machine operations executed
6748** by the prepared statement if that number is less than or equal
6749** to 2147483647.  The number of virtual machine operations can be
6750** used as a proxy for the total work done by the prepared statement.
6751** If the number of virtual machine operations exceeds 2147483647
6752** then the value returned by this statement status code is undefined.
6753** </dd>
6754** </dl>
6757#define SQLITE_STMTSTATUS_SORT              2
6759#define SQLITE_STMTSTATUS_VM_STEP           4
6762** CAPI3REF: Custom Page Cache Object
6764** The sqlite3_pcache type is opaque.  It is implemented by
6765** the pluggable module.  The SQLite core has no knowledge of
6766** its size or internal structure and never deals with the
6767** sqlite3_pcache object except by holding and passing pointers
6768** to the object.
6770** See [sqlite3_pcache_methods2] for additional information.
6772typedef struct sqlite3_pcache sqlite3_pcache;
6775** CAPI3REF: Custom Page Cache Object
6777** The sqlite3_pcache_page object represents a single page in the
6778** page cache.  The page cache will allocate instances of this
6779** object.  Various methods of the page cache use pointers to instances
6780** of this object as parameters or as their return value.
6782** See [sqlite3_pcache_methods2] for additional information.
6784typedef struct sqlite3_pcache_page sqlite3_pcache_page;
6785struct sqlite3_pcache_page {
6786  void *pBuf;        /* The content of the page */
6787  void *pExtra;      /* Extra information associated with the page */
6791** CAPI3REF: Application Defined Page Cache.
6792** KEYWORDS: {page cache}
6794** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
6795** register an alternative page cache implementation by passing in an
6796** instance of the sqlite3_pcache_methods2 structure.)^
6797** In many applications, most of the heap memory allocated by
6798** SQLite is used for the page cache.
6799** By implementing a
6800** custom page cache using this API, an application can better control
6801** the amount of memory consumed by SQLite, the way in which
6802** that memory is allocated and released, and the policies used to
6803** determine exactly which parts of a database file are cached and for
6804** how long.
6806** The alternative page cache mechanism is an
6807** extreme measure that is only needed by the most demanding applications.
6808** The built-in page cache is recommended for most uses.
6810** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
6811** internal buffer by SQLite within the call to [sqlite3_config].  Hence
6812** the application may discard the parameter after the call to
6813** [sqlite3_config()] returns.)^
6815** [[the xInit() page cache method]]
6816** ^(The xInit() method is called once for each effective
6817** call to [sqlite3_initialize()])^
6818** (usually only once during the lifetime of the process). ^(The xInit()
6819** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
6820** The intent of the xInit() method is to set up global data structures
6821** required by the custom page cache implementation.
6822** ^(If the xInit() method is NULL, then the
6823** built-in default page cache is used instead of the application defined
6824** page cache.)^
6826** [[the xShutdown() page cache method]]
6827** ^The xShutdown() method is called by [sqlite3_shutdown()].
6828** It can be used to clean up
6829** any outstanding resources before process shutdown, if required.
6830** ^The xShutdown() method may be NULL.
6832** ^SQLite automatically serializes calls to the xInit method,
6833** so the xInit method need not be threadsafe.  ^The
6834** xShutdown method is only called from [sqlite3_shutdown()] so it does
6835** not need to be threadsafe either.  All other methods must be threadsafe
6836** in multithreaded applications.
6838** ^SQLite will never invoke xInit() more than once without an intervening
6839** call to xShutdown().
6841** [[the xCreate() page cache methods]]
6842** ^SQLite invokes the xCreate() method to construct a new cache instance.
6843** SQLite will typically create one cache instance for each open database file,
6844** though this is not guaranteed. ^The
6845** first parameter, szPage, is the size in bytes of the pages that must
6846** be allocated by the cache.  ^szPage will always a power of two.  ^The
6847** second parameter szExtra is a number of bytes of extra storage
6848** associated with each page cache entry.  ^The szExtra parameter will
6849** a number less than 250.  SQLite will use the
6850** extra szExtra bytes on each page to store metadata about the underlying
6851** database page on disk.  The value passed into szExtra depends
6852** on the SQLite version, the target platform, and how SQLite was compiled.
6853** ^The third argument to xCreate(), bPurgeable, is true if the cache being
6854** created will be used to cache database pages of a file stored on disk, or
6855** false if it is used for an in-memory database. The cache implementation
6856** does not have to do anything special based with the value of bPurgeable;
6857** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
6858** never invoke xUnpin() except to deliberately delete a page.
6859** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
6860** false will always have the "discard" flag set to true.
6861** ^Hence, a cache created with bPurgeable false will
6862** never contain any unpinned pages.
6864** [[the xCachesize() page cache method]]
6865** ^(The xCachesize() method may be called at any time by SQLite to set the
6866** suggested maximum cache-size (number of pages stored by) the cache
6867** instance passed as the first argument. This is the value configured using
6868** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
6869** parameter, the implementation is not required to do anything with this
6870** value; it is advisory only.
6872** [[the xPagecount() page cache methods]]
6873** The xPagecount() method must return the number of pages currently
6874** stored in the cache, both pinned and unpinned.
6876** [[the xFetch() page cache methods]]
6877** The xFetch() method locates a page in the cache and returns a pointer to
6878** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
6879** The pBuf element of the returned sqlite3_pcache_page object will be a
6880** pointer to a buffer of szPage bytes used to store the content of a
6881** single database page.  The pExtra element of sqlite3_pcache_page will be
6882** a pointer to the szExtra bytes of extra storage that SQLite has requested
6883** for each entry in the page cache.
6885** The page to be fetched is determined by the key. ^The minimum key value
6886** is 1.  After it has been retrieved using xFetch, the page is considered
6887** to be "pinned".
6889** If the requested page is already in the page cache, then the page cache
6890** implementation must return a pointer to the page buffer with its content
6891** intact.  If the requested page is not already in the cache, then the
6892** cache implementation should use the value of the createFlag
6893** parameter to help it determined what action to take:
6895** <table border=1 width=85% align=center>
6896** <tr><th> createFlag <th> Behavior when page is not already in cache
6897** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
6898** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
6899**                 Otherwise return NULL.
6900** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
6901**                 NULL if allocating a new page is effectively impossible.
6902** </table>
6904** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
6905** will only use a createFlag of 2 after a prior call with a createFlag of 1
6906** failed.)^  In between the to xFetch() calls, SQLite may
6907** attempt to unpin one or more cache pages by spilling the content of
6908** pinned pages to disk and synching the operating system disk cache.
6910** [[the xUnpin() page cache method]]
6911** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
6912** as its second argument.  If the third parameter, discard, is non-zero,
6913** then the page must be evicted from the cache.
6914** ^If the discard parameter is
6915** zero, then the page may be discarded or retained at the discretion of
6916** page cache implementation. ^The page cache implementation
6917** may choose to evict unpinned pages at any time.
6919** The cache must not perform any reference counting. A single
6920** call to xUnpin() unpins the page regardless of the number of prior calls
6921** to xFetch().
6923** [[the xRekey() page cache methods]]
6924** The xRekey() method is used to change the key value associated with the
6925** page passed as the second argument. If the cache
6926** previously contains an entry associated with newKey, it must be
6927** discarded. ^Any prior cache entry associated with newKey is guaranteed not
6928** to be pinned.
6930** When SQLite calls the xTruncate() method, the cache must discard all
6931** existing cache entries with page numbers (keys) greater than or equal
6932** to the value of the iLimit parameter passed to xTruncate(). If any
6933** of these pages are pinned, they are implicitly unpinned, meaning that
6934** they can be safely discarded.
6936** [[the xDestroy() page cache method]]
6937** ^The xDestroy() method is used to delete a cache allocated by xCreate().
6938** All resources associated with the specified cache should be freed. ^After
6939** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
6940** handle invalid, and will not use it with any other sqlite3_pcache_methods2
6941** functions.
6943** [[the xShrink() page cache method]]
6944** ^SQLite invokes the xShrink() method when it wants the page cache to
6945** free up as much of heap memory as possible.  The page cache implementation
6946** is not obligated to free any memory, but well-behaved implementations should
6947** do their best.
6949typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
6950struct sqlite3_pcache_methods2 {
6951  int iVersion;
6952  void *pArg;
6953  int (*xInit)(void*);
6954  void (*xShutdown)(void*);
6955  sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
6956  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6957  int (*xPagecount)(sqlite3_pcache*);
6958  sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6959  void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
6960  void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
6961      unsigned oldKey, unsigned newKey);
6962  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6963  void (*xDestroy)(sqlite3_pcache*);
6964  void (*xShrink)(sqlite3_pcache*);
6968** This is the obsolete pcache_methods object that has now been replaced
6969** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
6970** retained in the header file for backwards compatibility only.
6972typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
6973struct sqlite3_pcache_methods {
6974  void *pArg;
6975  int (*xInit)(void*);
6976  void (*xShutdown)(void*);
6977  sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
6978  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6979  int (*xPagecount)(sqlite3_pcache*);
6980  void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6981  void (*xUnpin)(sqlite3_pcache*, void*, int discard);
6982  void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
6983  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6984  void (*xDestroy)(sqlite3_pcache*);
6989** CAPI3REF: Online Backup Object
6991** The sqlite3_backup object records state information about an ongoing
6992** online backup operation.  ^The sqlite3_backup object is created by
6993** a call to [sqlite3_backup_init()] and is destroyed by a call to
6994** [sqlite3_backup_finish()].
6996** See Also: [Using the SQLite Online Backup API]
6998typedef struct sqlite3_backup sqlite3_backup;
7001** CAPI3REF: Online Backup API.
7003** The backup API copies the content of one database into another.
7004** It is useful either for creating backups of databases or
7005** for copying in-memory databases to or from persistent files.
7007** See Also: [Using the SQLite Online Backup API]
7009** ^SQLite holds a write transaction open on the destination database file
7010** for the duration of the backup operation.
7011** ^The source database is read-locked only while it is being read;
7012** it is not locked continuously for the entire backup operation.
7013** ^Thus, the backup may be performed on a live source database without
7014** preventing other database connections from
7015** reading or writing to the source database while the backup is underway.
7017** ^(To perform a backup operation:
7018**   <ol>
7019**     <li><b>sqlite3_backup_init()</b> is called once to initialize the
7020**         backup,
7021**     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
7022**         the data between the two databases, and finally
7023**     <li><b>sqlite3_backup_finish()</b> is called to release all resources
7024**         associated with the backup operation.
7025**   </ol>)^
7026** There should be exactly one call to sqlite3_backup_finish() for each
7027** successful call to sqlite3_backup_init().
7029** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
7031** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
7032** [database connection] associated with the destination database
7033** and the database name, respectively.
7034** ^The database name is "main" for the main database, "temp" for the
7035** temporary database, or the name specified after the AS keyword in
7036** an [ATTACH] statement for an attached database.
7037** ^The S and M arguments passed to
7038** sqlite3_backup_init(D,N,S,M) identify the [database connection]
7039** and database name of the source database, respectively.
7040** ^The source and destination [database connections] (parameters S and D)
7041** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
7042** an error.
7044** ^A call to sqlite3_backup_init() will fail, returning SQLITE_ERROR, if
7045** there is already a read or read-write transaction open on the
7046** destination database.
7048** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
7049** returned and an error code and error message are stored in the
7050** destination [database connection] D.
7051** ^The error code and message for the failed call to sqlite3_backup_init()
7052** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
7053** [sqlite3_errmsg16()] functions.
7054** ^A successful call to sqlite3_backup_init() returns a pointer to an
7055** [sqlite3_backup] object.
7056** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
7057** sqlite3_backup_finish() functions to perform the specified backup
7058** operation.
7060** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
7062** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
7063** the source and destination databases specified by [sqlite3_backup] object B.
7064** ^If N is negative, all remaining source pages are copied.
7065** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
7066** are still more pages to be copied, then the function returns [SQLITE_OK].
7067** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
7068** from source to destination, then it returns [SQLITE_DONE].
7069** ^If an error occurs while running sqlite3_backup_step(B,N),
7070** then an [error code] is returned. ^As well as [SQLITE_OK] and
7071** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
7073** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
7075** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
7076** <ol>
7077** <li> the destination database was opened read-only, or
7078** <li> the destination database is using write-ahead-log journaling
7079** and the destination and source page sizes differ, or
7080** <li> the destination database is an in-memory database and the
7081** destination and source page sizes differ.
7082** </ol>)^
7084** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
7085** the [sqlite3_busy_handler | busy-handler function]
7086** is invoked (if one is specified). ^If the
7087** busy-handler returns non-zero before the lock is available, then
7088** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
7089** sqlite3_backup_step() can be retried later. ^If the source
7090** [database connection]
7091** is being used to write to the source database when sqlite3_backup_step()
7092** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
7093** case the call to sqlite3_backup_step() can be retried later on. ^(If
7095** [SQLITE_READONLY] is returned, then
7096** there is no point in retrying the call to sqlite3_backup_step(). These
7097** errors are considered fatal.)^  The application must accept
7098** that the backup operation has failed and pass the backup operation handle
7099** to the sqlite3_backup_finish() to release associated resources.
7101** ^The first call to sqlite3_backup_step() obtains an exclusive lock
7102** on the destination file. ^The exclusive lock is not released until either
7103** sqlite3_backup_finish() is called or the backup operation is complete
7104** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
7105** sqlite3_backup_step() obtains a [shared lock] on the source database that
7106** lasts for the duration of the sqlite3_backup_step() call.
7107** ^Because the source database is not locked between calls to
7108** sqlite3_backup_step(), the source database may be modified mid-way
7109** through the backup process.  ^If the source database is modified by an
7110** external process or via a database connection other than the one being
7111** used by the backup operation, then the backup will be automatically
7112** restarted by the next call to sqlite3_backup_step(). ^If the source
7113** database is modified by the using the same database connection as is used
7114** by the backup operation, then the backup database is automatically
7115** updated at the same time.
7117** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
7119** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
7120** application wishes to abandon the backup operation, the application
7121** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
7122** ^The sqlite3_backup_finish() interfaces releases all
7123** resources associated with the [sqlite3_backup] object.
7124** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
7125** active write-transaction on the destination database is rolled back.
7126** The [sqlite3_backup] object is invalid
7127** and may not be used following a call to sqlite3_backup_finish().
7129** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
7130** sqlite3_backup_step() errors occurred, regardless or whether or not
7131** sqlite3_backup_step() completed.
7132** ^If an out-of-memory condition or IO error occurred during any prior
7133** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
7134** sqlite3_backup_finish() returns the corresponding [error code].
7136** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
7137** is not a permanent error and does not affect the return value of
7138** sqlite3_backup_finish().
7140** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]
7141** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
7143** ^Each call to sqlite3_backup_step() sets two values inside
7144** the [sqlite3_backup] object: the number of pages still to be backed
7145** up and the total number of pages in the source database file.
7146** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
7147** retrieve these two values, respectively.
7149** ^The values returned by these functions are only updated by
7150** sqlite3_backup_step(). ^If the source database is modified during a backup
7151** operation, then the values are not updated to account for any extra
7152** pages that need to be updated or the size of the source database file
7153** changing.
7155** <b>Concurrent Usage of Database Handles</b>
7157** ^The source [database connection] may be used by the application for other
7158** purposes while a backup operation is underway or being initialized.
7159** ^If SQLite is compiled and configured to support threadsafe database
7160** connections, then the source database connection may be used concurrently
7161** from within other threads.
7163** However, the application must guarantee that the destination
7164** [database connection] is not passed to any other API (by any thread) after
7165** sqlite3_backup_init() is called and before the corresponding call to
7166** sqlite3_backup_finish().  SQLite does not currently check to see
7167** if the application incorrectly accesses the destination [database connection]
7168** and so no error code is reported, but the operations may malfunction
7169** nevertheless.  Use of the destination database connection while a
7170** backup is in progress might also also cause a mutex deadlock.
7172** If running in [shared cache mode], the application must
7173** guarantee that the shared cache used by the destination database
7174** is not accessed while the backup is running. In practice this means
7175** that the application must guarantee that the disk file being
7176** backed up to is not accessed by any connection within the process,
7177** not just the specific connection that was passed to sqlite3_backup_init().
7179** The [sqlite3_backup] object itself is partially threadsafe. Multiple
7180** threads may safely make multiple concurrent calls to sqlite3_backup_step().
7181** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
7182** APIs are not strictly speaking threadsafe. If they are invoked at the
7183** same time as another thread is invoking sqlite3_backup_step() it is
7184** possible that they return invalid values.
7186SQLITE_API sqlite3_backup *sqlite3_backup_init(
7187  sqlite3 *pDest,                        /* Destination database handle */
7188  const char *zDestName,                 /* Destination database name */
7189  sqlite3 *pSource,                      /* Source database handle */
7190  const char *zSourceName                /* Source database name */
7192SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
7193SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
7194SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
7195SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
7198** CAPI3REF: Unlock Notification
7200** ^When running in shared-cache mode, a database operation may fail with
7201** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
7202** individual tables within the shared-cache cannot be obtained. See
7203** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
7204** ^This API may be used to register a callback that SQLite will invoke
7205** when the connection currently holding the required lock relinquishes it.
7206** ^This API is only available if the library was compiled with the
7207** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
7209** See Also: [Using the SQLite Unlock Notification Feature].
7211** ^Shared-cache locks are released when a database connection concludes
7212** its current transaction, either by committing it or rolling it back.
7214** ^When a connection (known as the blocked connection) fails to obtain a
7215** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
7216** identity of the database connection (the blocking connection) that
7217** has locked the required resource is stored internally. ^After an
7218** application receives an SQLITE_LOCKED error, it may call the
7219** sqlite3_unlock_notify() method with the blocked connection handle as
7220** the first argument to register for a callback that will be invoked
7221** when the blocking connections current transaction is concluded. ^The
7222** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
7223** call that concludes the blocking connections transaction.
7225** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
7226** there is a chance that the blocking connection will have already
7227** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
7228** If this happens, then the specified callback is invoked immediately,
7229** from within the call to sqlite3_unlock_notify().)^
7231** ^If the blocked connection is attempting to obtain a write-lock on a
7232** shared-cache table, and more than one other connection currently holds
7233** a read-lock on the same table, then SQLite arbitrarily selects one of
7234** the other connections to use as the blocking connection.
7236** ^(There may be at most one unlock-notify callback registered by a
7237** blocked connection. If sqlite3_unlock_notify() is called when the
7238** blocked connection already has a registered unlock-notify callback,
7239** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
7240** called with a NULL pointer as its second argument, then any existing
7241** unlock-notify callback is canceled. ^The blocked connections
7242** unlock-notify callback may also be canceled by closing the blocked
7243** connection using [sqlite3_close()].
7245** The unlock-notify callback is not reentrant. If an application invokes
7246** any sqlite3_xxx API functions from within an unlock-notify callback, a
7247** crash or deadlock may be the result.
7249** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
7250** returns SQLITE_OK.
7252** <b>Callback Invocation Details</b>
7254** When an unlock-notify callback is registered, the application provides a
7255** single void* pointer that is passed to the callback when it is invoked.
7256** However, the signature of the callback function allows SQLite to pass
7257** it an array of void* context pointers. The first argument passed to
7258** an unlock-notify callback is a pointer to an array of void* pointers,
7259** and the second is the number of entries in the array.
7261** When a blocking connections transaction is concluded, there may be
7262** more than one blocked connection that has registered for an unlock-notify
7263** callback. ^If two or more such blocked connections have specified the
7264** same callback function, then instead of invoking the callback function
7265** multiple times, it is invoked once with the set of void* context pointers
7266** specified by the blocked connections bundled together into an array.
7267** This gives the application an opportunity to prioritize any actions
7268** related to the set of unblocked database connections.
7270** <b>Deadlock Detection</b>
7272** Assuming that after registering for an unlock-notify callback a
7273** database waits for the callback to be issued before taking any further
7274** action (a reasonable assumption), then using this API may cause the
7275** application to deadlock. For example, if connection X is waiting for
7276** connection Y's transaction to be concluded, and similarly connection
7277** Y is waiting on connection X's transaction, then neither connection
7278** will proceed and the system may remain deadlocked indefinitely.
7280** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
7281** detection. ^If a given call to sqlite3_unlock_notify() would put the
7282** system in a deadlocked state, then SQLITE_LOCKED is returned and no
7283** unlock-notify callback is registered. The system is said to be in
7284** a deadlocked state if connection A has registered for an unlock-notify
7285** callback on the conclusion of connection B's transaction, and connection
7286** B has itself registered for an unlock-notify callback when connection
7287** A's transaction is concluded. ^Indirect deadlock is also detected, so
7288** the system is also considered to be deadlocked if connection B has
7289** registered for an unlock-notify callback on the conclusion of connection
7290** C's transaction, where connection C is waiting on connection A. ^Any
7291** number of levels of indirection are allowed.
7293** <b>The "DROP TABLE" Exception</b>
7295** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
7296** always appropriate to call sqlite3_unlock_notify(). There is however,
7297** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
7298** SQLite checks if there are any currently executing SELECT statements
7299** that belong to the same connection. If there are, SQLITE_LOCKED is
7300** returned. In this case there is no "blocking connection", so invoking
7301** sqlite3_unlock_notify() results in the unlock-notify callback being
7302** invoked immediately. If the application then re-attempts the "DROP TABLE"
7303** or "DROP INDEX" query, an infinite loop might be the result.
7305** One way around this problem is to check the extended error code returned
7306** by an sqlite3_step() call. ^(If there is a blocking connection, then the
7307** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
7308** the special "DROP TABLE/INDEX" case, the extended error code is just
7311SQLITE_API int sqlite3_unlock_notify(
7312  sqlite3 *pBlocked,                          /* Waiting connection */
7313  void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
7314  void *pNotifyArg                            /* Argument to pass to xNotify */
7319** CAPI3REF: String Comparison
7321** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
7322** and extensions to compare the contents of two buffers containing UTF-8
7323** strings in a case-independent fashion, using the same definition of "case
7324** independence" that SQLite uses internally when comparing identifiers.
7326SQLITE_API int sqlite3_stricmp(const char *, const char *);
7327SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
7330** CAPI3REF: String Globbing
7332** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches
7333** the glob pattern P, and it returns non-zero if string X does not match
7334** the glob pattern P.  ^The definition of glob pattern matching used in
7335** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
7336** SQL dialect used by SQLite.  ^The sqlite3_strglob(P,X) function is case
7337** sensitive.
7339** Note that this routine returns zero on a match and non-zero if the strings
7340** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
7342SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
7345** CAPI3REF: Error Logging Interface
7347** ^The [sqlite3_log()] interface writes a message into the [error log]
7348** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
7349** ^If logging is enabled, the zFormat string and subsequent arguments are
7350** used with [sqlite3_snprintf()] to generate the final output string.
7352** The sqlite3_log() interface is intended for use by extensions such as
7353** virtual tables, collating functions, and SQL functions.  While there is
7354** nothing to prevent an application from calling sqlite3_log(), doing so
7355** is considered bad form.
7357** The zFormat string must not be NULL.
7359** To avoid deadlocks and other threading problems, the sqlite3_log() routine
7360** will not use dynamically allocated memory.  The log message is stored in
7361** a fixed-length buffer on the stack.  If the log message is longer than
7362** a few hundred characters, it will be truncated to the length of the
7363** buffer.
7365SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
7368** CAPI3REF: Write-Ahead Log Commit Hook
7370** ^The [sqlite3_wal_hook()] function is used to register a callback that
7371** is invoked each time data is committed to a database in wal mode.
7373** ^(The callback is invoked by SQLite after the commit has taken place and
7374** the associated write-lock on the database released)^, so the implementation
7375** may read, write or [checkpoint] the database as required.
7377** ^The first parameter passed to the callback function when it is invoked
7378** is a copy of the third parameter passed to sqlite3_wal_hook() when
7379** registering the callback. ^The second is a copy of the database handle.
7380** ^The third parameter is the name of the database that was written to -
7381** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
7382** is the number of pages currently in the write-ahead log file,
7383** including those that were just committed.
7385** The callback function should normally return [SQLITE_OK].  ^If an error
7386** code is returned, that error will propagate back up through the
7387** SQLite code base to cause the statement that provoked the callback
7388** to report an error, though the commit will have still occurred. If the
7389** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
7390** that does not correspond to any valid SQLite error code, the results
7391** are undefined.
7393** A single database handle may have at most a single write-ahead log callback
7394** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
7395** previously registered write-ahead log callback. ^Note that the
7396** [sqlite3_wal_autocheckpoint()] interface and the
7397** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
7398** those overwrite any prior [sqlite3_wal_hook()] settings.
7400SQLITE_API void *sqlite3_wal_hook(
7401  sqlite3*,
7402  int(*)(void *,sqlite3*,const char*,int),
7403  void*
7407** CAPI3REF: Configure an auto-checkpoint
7409** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
7410** [sqlite3_wal_hook()] that causes any database on [database connection] D
7411** to automatically [checkpoint]
7412** after committing a transaction if there are N or
7413** more frames in the [write-ahead log] file.  ^Passing zero or
7414** a negative value as the nFrame parameter disables automatic
7415** checkpoints entirely.
7417** ^The callback registered by this function replaces any existing callback
7418** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
7419** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
7420** configured by this function.
7422** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
7423** from SQL.
7425** ^Checkpoints initiated by this mechanism are
7426** [sqlite3_wal_checkpoint_v2|PASSIVE].
7428** ^Every new [database connection] defaults to having the auto-checkpoint
7429** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
7430** pages.  The use of this interface
7431** is only necessary if the default setting is found to be suboptimal
7432** for a particular application.
7434SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
7437** CAPI3REF: Checkpoint a database
7439** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
7440** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
7442** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
7443** [write-ahead log] for database X on [database connection] D to be
7444** transferred into the database file and for the write-ahead log to
7445** be reset.  See the [checkpointing] documentation for addition
7446** information.
7448** This interface used to be the only way to cause a checkpoint to
7449** occur.  But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
7450** interface was added.  This interface is retained for backwards
7451** compatibility and as a convenience for applications that need to manually
7452** start a callback but which do not need the full power (and corresponding
7453** complication) of [sqlite3_wal_checkpoint_v2()].
7455SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
7458** CAPI3REF: Checkpoint a database
7460** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
7461** operation on database X of [database connection] D in mode M.  Status
7462** information is written back into integers pointed to by L and C.)^
7463** ^(The M parameter must be a valid [checkpoint mode]:)^
7465** <dl>
7467**   ^Checkpoint as many frames as possible without waiting for any database
7468**   readers or writers to finish, then sync the database file if all frames
7469**   in the log were checkpointed. ^The [busy-handler callback]
7470**   is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
7471**   ^On the other hand, passive mode might leave the checkpoint unfinished
7472**   if there are concurrent readers or writers.
7475**   ^This mode blocks (it invokes the
7476**   [sqlite3_busy_handler|busy-handler callback]) until there is no
7477**   database writer and all readers are reading from the most recent database
7478**   snapshot. ^It then checkpoints all frames in the log file and syncs the
7479**   database file. ^This mode blocks new database writers while it is pending,
7480**   but new database readers are allowed to continue unimpeded.
7483**   ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
7484**   that after checkpointing the log file it blocks (calls the
7485**   [busy-handler callback])
7486**   until all readers are reading from the database file only. ^This ensures
7487**   that the next writer will restart the log file from the beginning.
7488**   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
7489**   database writer attempts while it is pending, but does not impede readers.
7492**   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
7493**   addition that it also truncates the log file to zero bytes just prior
7494**   to a successful return.
7495** </dl>
7497** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
7498** the log file or to -1 if the checkpoint could not run because
7499** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
7500** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
7501** log file (including any that were already checkpointed before the function
7502** was called) or to -1 if the checkpoint could not run due to an error or
7503** because the database is not in WAL mode. ^Note that upon successful
7504** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
7505** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
7507** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
7508** any other process is running a checkpoint operation at the same time, the
7509** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
7510** busy-handler configured, it will not be invoked in this case.
7512** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
7513** exclusive "writer" lock on the database file. ^If the writer lock cannot be
7514** obtained immediately, and a busy-handler is configured, it is invoked and
7515** the writer lock retried until either the busy-handler returns 0 or the lock
7516** is successfully obtained. ^The busy-handler is also invoked while waiting for
7517** database readers as described above. ^If the busy-handler returns 0 before
7518** the writer lock is obtained or while waiting for database readers, the
7519** checkpoint operation proceeds from that point in the same way as
7520** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
7521** without blocking any further. ^SQLITE_BUSY is returned in this case.
7523** ^If parameter zDb is NULL or points to a zero length string, then the
7524** specified operation is attempted on all WAL databases [attached] to
7525** [database connection] db.  In this case the
7526** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
7527** an SQLITE_BUSY error is encountered when processing one or more of the
7528** attached WAL databases, the operation is still attempted on any remaining
7529** attached databases and SQLITE_BUSY is returned at the end. ^If any other
7530** error occurs while processing an attached database, processing is abandoned
7531** and the error code is returned to the caller immediately. ^If no error
7532** (SQLITE_BUSY or otherwise) is encountered while processing the attached
7533** databases, SQLITE_OK is returned.
7535** ^If database zDb is the name of an attached database that is not in WAL
7536** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
7537** zDb is not NULL (or a zero length string) and is not the name of any
7538** attached database, SQLITE_ERROR is returned to the caller.
7540** ^Unless it returns SQLITE_MISUSE,
7541** the sqlite3_wal_checkpoint_v2() interface
7542** sets the error information that is queried by
7543** [sqlite3_errcode()] and [sqlite3_errmsg()].
7545** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
7546** from SQL.
7548SQLITE_API int sqlite3_wal_checkpoint_v2(
7549  sqlite3 *db,                    /* Database handle */
7550  const char *zDb,                /* Name of attached database (or NULL) */
7551  int eMode,                      /* SQLITE_CHECKPOINT_* value */
7552  int *pnLog,                     /* OUT: Size of WAL log in frames */
7553  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
7557** CAPI3REF: Checkpoint Mode Values
7558** KEYWORDS: {checkpoint mode}
7560** These constants define all valid values for the "checkpoint mode" passed
7561** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
7562** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
7563** meaning of each of these checkpoint modes.
7565#define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
7566#define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
7567#define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for for readers */
7568#define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */
7571** CAPI3REF: Virtual Table Interface Configuration
7573** This function may be called by either the [xConnect] or [xCreate] method
7574** of a [virtual table] implementation to configure
7575** various facets of the virtual table interface.
7577** If this interface is invoked outside the context of an xConnect or
7578** xCreate virtual table method then the behavior is undefined.
7580** At present, there is only one option that may be configured using
7581** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].)  Further options
7582** may be added in the future.
7584SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
7587** CAPI3REF: Virtual Table Configuration Options
7589** These macros define the various options to the
7590** [sqlite3_vtab_config()] interface that [virtual table] implementations
7591** can use to customize and optimize their behavior.
7593** <dl>
7595** <dd>Calls of the form
7596** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
7597** where X is an integer.  If X is zero, then the [virtual table] whose
7598** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
7599** support constraints.  In this configuration (which is the default) if
7600** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
7601** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
7602** specified as part of the users SQL statement, regardless of the actual
7603** ON CONFLICT mode specified.
7605** If X is non-zero, then the virtual table implementation guarantees
7606** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
7607** any modifications to internal or persistent data structures have been made.
7608** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
7609** is able to roll back a statement or database transaction, and abandon
7610** or continue processing the current SQL statement as appropriate.
7611** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
7612** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
7613** had been ABORT.
7615** Virtual table implementations that are required to handle OR REPLACE
7616** must do so within the [xUpdate] method. If a call to the
7617** [sqlite3_vtab_on_conflict()] function indicates that the current ON
7618** CONFLICT policy is REPLACE, the virtual table implementation should
7619** silently replace the appropriate rows within the xUpdate callback and
7620** return SQLITE_OK. Or, if this is not possible, it may return
7621** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
7622** constraint handling.
7623** </dl>
7628** CAPI3REF: Determine The Virtual Table Conflict Policy
7630** This function may only be called from within a call to the [xUpdate] method
7631** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
7632** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
7633** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
7634** of the SQL statement that triggered the call to the [xUpdate] method of the
7635** [virtual table].
7637SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
7640** CAPI3REF: Conflict resolution modes
7641** KEYWORDS: {conflict resolution mode}
7643** These constants are returned by [sqlite3_vtab_on_conflict()] to
7644** inform a [virtual table] implementation what the [ON CONFLICT] mode
7645** is for the SQL statement being evaluated.
7647** Note that the [SQLITE_IGNORE] constant is also used as a potential
7648** return value from the [sqlite3_set_authorizer()] callback and that
7649** [SQLITE_ABORT] is also a [result code].
7651#define SQLITE_ROLLBACK 1
7652/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
7653#define SQLITE_FAIL     3
7654/* #define SQLITE_ABORT 4  // Also an error code */
7655#define SQLITE_REPLACE  5
7658** CAPI3REF: Prepared Statement Scan Status Opcodes
7659** KEYWORDS: {scanstatus options}
7661** The following constants can be used for the T parameter to the
7662** [sqlite3_stmt_scanstatus(S,X,T,V)] interface.  Each constant designates a
7663** different metric for sqlite3_stmt_scanstatus() to return.
7665** When the value returned to V is a string, space to hold that string is
7666** managed by the prepared statement S and will be automatically freed when
7667** S is finalized.
7669** <dl>
7671** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be
7672** set to the total number of times that the X-th loop has run.</dd>
7675** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set
7676** to the total number of rows examined by all iterations of the X-th loop.</dd>