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/************** Begin file sqliteInt.h ***************************************/
27** 2001 September 15
29** The author disclaims copyright to this source code.  In place of
30** a legal notice, here is a blessing:
32**    May you do good and not evil.
33**    May you find forgiveness for yourself and forgive others.
34**    May you share freely, never taking more than you give.
37** Internal interface definitions for SQLite.
40#ifndef _SQLITEINT_H_
41#define _SQLITEINT_H_
44** Include the header file used to customize the compiler options for MSVC.
45** This should be done first so that it can successfully prevent spurious
46** compiler warnings due to subsequent content in this file and other files
47** that are included by this file.
49/************** Include msvc.h in the middle of sqliteInt.h ******************/
50/************** Begin file msvc.h ********************************************/
52** 2015 January 12
54** The author disclaims copyright to this source code.  In place of
55** a legal notice, here is a blessing:
57**    May you do good and not evil.
58**    May you find forgiveness for yourself and forgive others.
59**    May you share freely, never taking more than you give.
63** This file contains code that is specific to MSVC.
65#ifndef _MSVC_H_
66#define _MSVC_H_
68#if defined(_MSC_VER)
69#pragma warning(disable : 4054)
70#pragma warning(disable : 4055)
71#pragma warning(disable : 4100)
72#pragma warning(disable : 4127)
73#pragma warning(disable : 4130)
74#pragma warning(disable : 4152)
75#pragma warning(disable : 4189)
76#pragma warning(disable : 4206)
77#pragma warning(disable : 4210)
78#pragma warning(disable : 4232)
79#pragma warning(disable : 4244)
80#pragma warning(disable : 4305)
81#pragma warning(disable : 4306)
82#pragma warning(disable : 4702)
83#pragma warning(disable : 4706)
84#endif /* defined(_MSC_VER) */
86#endif /* _MSVC_H_ */
88/************** End of msvc.h ************************************************/
89/************** Continuing where we left off in sqliteInt.h ******************/
92** Special setup for VxWorks
94/************** Include vxworks.h in the middle of sqliteInt.h ***************/
95/************** Begin file vxworks.h *****************************************/
97** 2015-03-02
99** The author disclaims copyright to this source code.  In place of
100** a legal notice, here is a blessing:
102**    May you do good and not evil.
103**    May you find forgiveness for yourself and forgive others.
104**    May you share freely, never taking more than you give.
108** This file contains code that is specific to Wind River's VxWorks
110#if defined(__RTP__) || defined(_WRS_KERNEL)
111/* This is VxWorks.  Set up things specially for that OS
113#include <vxWorks.h>
114#include <pthread.h>  /* amalgamator: dontcache */
115#define OS_VXWORKS 1
116#define SQLITE_OS_OTHER 0
120#define HAVE_UTIME 1
122/* This is not VxWorks. */
123#define OS_VXWORKS 0
124#endif /* defined(_WRS_KERNEL) */
126/************** End of vxworks.h *********************************************/
127/************** Continuing where we left off in sqliteInt.h ******************/
130** These #defines should enable >2GB file support on POSIX if the
131** underlying operating system supports it.  If the OS lacks
132** large file support, or if the OS is windows, these should be no-ops.
134** Ticket #2739:  The _LARGEFILE_SOURCE macro must appear before any
135** system #includes.  Hence, this block of code must be the very first
136** code in all source files.
138** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch
139** on the compiler command line.  This is necessary if you are compiling
140** on a recent machine (ex: Red Hat 7.2) but you want your code to work
141** on an older machine (ex: Red Hat 6.0).  If you compile on Red Hat 7.2
142** without this option, LFS is enable.  But LFS does not exist in the kernel
143** in Red Hat 6.0, so the code won't work.  Hence, for maximum binary
144** portability you should omit LFS.
146** The previous paragraph was written in 2005.  (This paragraph is written
147** on 2008-11-28.) These days, all Linux kernels support large files, so
148** you should probably leave LFS enabled.  But some embedded platforms might
149** lack LFS in which case the SQLITE_DISABLE_LFS macro might still be useful.
151** Similar is true for Mac OS X.  LFS is only supported on Mac OS X 9 and later.
154# define _LARGE_FILE       1
155# ifndef _FILE_OFFSET_BITS
156#   define _FILE_OFFSET_BITS 64
157# endif
158# define _LARGEFILE_SOURCE 1
161/* Needed for various definitions... */
162#if defined(__GNUC__) && !defined(_GNU_SOURCE)
163# define _GNU_SOURCE
166#if defined(__OpenBSD__) && !defined(_BSD_SOURCE)
167# define _BSD_SOURCE
171** For MinGW, check to see if we can include the header file containing its
172** version information, among other things.  Normally, this internal MinGW
173** header file would [only] be included automatically by other MinGW header
174** files; however, the contained version information is now required by this
175** header file to work around binary compatibility issues (see below) and
176** this is the only known way to reliably obtain it.  This entire #if block
177** would be completely unnecessary if there was any other way of detecting
178** MinGW via their preprocessor (e.g. if they customized their GCC to define
179** some MinGW-specific macros).  When compiling for MinGW, either the
180** _HAVE_MINGW_H or _HAVE__MINGW_H (note the extra underscore) macro must be
181** defined; otherwise, detection of conditions specific to MinGW will be
182** disabled.
184#if defined(_HAVE_MINGW_H)
185# include "mingw.h"
186#elif defined(_HAVE__MINGW_H)
187# include "_mingw.h"
191** For MinGW version 4.x (and higher), check to see if the _USE_32BIT_TIME_T
192** define is required to maintain binary compatibility with the MSVC runtime
193** library in use (e.g. for Windows XP).
195#if !defined(_USE_32BIT_TIME_T) && !defined(_USE_64BIT_TIME_T) && \
196    defined(_WIN32) && !defined(_WIN64) && \
197    defined(__MINGW_MAJOR_VERSION) && __MINGW_MAJOR_VERSION >= 4 && \
198    defined(__MSVCRT__)
199# define _USE_32BIT_TIME_T
202/* The public SQLite interface.  The _FILE_OFFSET_BITS macro must appear
203** first in QNX.  Also, the _USE_32BIT_TIME_T macro must appear first for
204** MinGW.
206/************** Include sqlite3.h in the middle of sqliteInt.h ***************/
207/************** Begin file sqlite3.h *****************************************/
209** 2001 September 15
211** The author disclaims copyright to this source code.  In place of
212** a legal notice, here is a blessing:
214**    May you do good and not evil.
215**    May you find forgiveness for yourself and forgive others.
216**    May you share freely, never taking more than you give.
219** This header file defines the interface that the SQLite library
220** presents to client programs.  If a C-function, structure, datatype,
221** or constant definition does not appear in this file, then it is
222** not a published API of SQLite, is subject to change without
223** notice, and should not be referenced by programs that use SQLite.
225** Some of the definitions that are in this file are marked as
226** "experimental".  Experimental interfaces are normally new
227** features recently added to SQLite.  We do not anticipate changes
228** to experimental interfaces but reserve the right to make minor changes
229** if experience from use "in the wild" suggest such changes are prudent.
231** The official C-language API documentation for SQLite is derived
232** from comments in this file.  This file is the authoritative source
233** on how SQLite interfaces are suppose to operate.
235** The name of this file under configuration management is "sqlite.h.in".
236** The makefile makes some minor changes to this file (such as inserting
237** the version number) and changes its name to "sqlite3.h" as
238** part of the build process.
240#ifndef _SQLITE3_H_
241#define _SQLITE3_H_
242#include <stdarg.h>     /* Needed for the definition of va_list */
245** Make sure we can call this stuff from C++.
247#if 0
248extern "C" {
253** Provide the ability to override linkage features of the interface.
255#ifndef SQLITE_EXTERN
256# define SQLITE_EXTERN extern
258#ifndef SQLITE_API
259# define SQLITE_API
261#ifndef SQLITE_CDECL
262# define SQLITE_CDECL
265# define SQLITE_STDCALL
269** These no-op macros are used in front of interfaces to mark those
270** interfaces as either deprecated or experimental.  New applications
271** should not use deprecated interfaces - they are supported for backwards
272** compatibility only.  Application writers should be aware that
273** experimental interfaces are subject to change in point releases.
275** These macros used to resolve to various kinds of compiler magic that
276** would generate warning messages when they were used.  But that
277** compiler magic ended up generating such a flurry of bug reports
278** that we have taken it all out and gone back to using simple
279** noop macros.
285** Ensure these symbols were not defined by some previous header file.
295** CAPI3REF: Compile-Time Library Version Numbers
297** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
298** evaluates to a string literal that is the SQLite version in the
299** format "X.Y.Z" where X is the major version number (always 3 for
300** SQLite3) and Y is the minor version number and Z is the release number.)^
301** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
302** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
303** numbers used in [SQLITE_VERSION].)^
304** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
305** be larger than the release from which it is derived.  Either Y will
306** be held constant and Z will be incremented or else Y will be incremented
307** and Z will be reset to zero.
309** Since version 3.6.18, SQLite source code has been stored in the
310** <a href="http://www.fossil-scm.org/">Fossil configuration management
311** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
312** a string which identifies a particular check-in of SQLite
313** within its configuration management system.  ^The SQLITE_SOURCE_ID
314** string contains the date and time of the check-in (UTC) and an SHA1
315** hash of the entire source tree.
317** See also: [sqlite3_libversion()],
318** [sqlite3_libversion_number()], [sqlite3_sourceid()],
319** [sqlite_version()] and [sqlite_source_id()].
321#define SQLITE_VERSION        ""
322#define SQLITE_VERSION_NUMBER 3008010
323#define SQLITE_SOURCE_ID      "2015-05-20 18:17:19 2ef4f3a5b1d1d0c4338f8243d40a2452cc1f7fe4"
326** CAPI3REF: Run-Time Library Version Numbers
327** KEYWORDS: sqlite3_version, sqlite3_sourceid
329** These interfaces provide the same information as the [SQLITE_VERSION],
330** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
331** but are associated with the library instead of the header file.  ^(Cautious
332** programmers might include assert() statements in their application to
333** verify that values returned by these interfaces match the macros in
334** the header, and thus insure that the application is
335** compiled with matching library and header files.
337** <blockquote><pre>
338** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
339** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
340** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
341** </pre></blockquote>)^
343** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
344** macro.  ^The sqlite3_libversion() function returns a pointer to the
345** to the sqlite3_version[] string constant.  The sqlite3_libversion()
346** function is provided for use in DLLs since DLL users usually do not have
347** direct access to string constants within the DLL.  ^The
348** sqlite3_libversion_number() function returns an integer equal to
349** [SQLITE_VERSION_NUMBER].  ^The sqlite3_sourceid() function returns
350** a pointer to a string constant whose value is the same as the
351** [SQLITE_SOURCE_ID] C preprocessor macro.
353** See also: [sqlite_version()] and [sqlite_source_id()].
355SQLITE_API const char sqlite3_version[] = SQLITE_VERSION;
356SQLITE_API const char *SQLITE_STDCALL sqlite3_libversion(void);
357SQLITE_API const char *SQLITE_STDCALL sqlite3_sourceid(void);
358SQLITE_API int SQLITE_STDCALL sqlite3_libversion_number(void);
361** CAPI3REF: Run-Time Library Compilation Options Diagnostics
363** ^The sqlite3_compileoption_used() function returns 0 or 1
364** indicating whether the specified option was defined at
365** compile time.  ^The SQLITE_ prefix may be omitted from the
366** option name passed to sqlite3_compileoption_used().
368** ^The sqlite3_compileoption_get() function allows iterating
369** over the list of options that were defined at compile time by
370** returning the N-th compile time option string.  ^If N is out of range,
371** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_
372** prefix is omitted from any strings returned by
373** sqlite3_compileoption_get().
375** ^Support for the diagnostic functions sqlite3_compileoption_used()
376** and sqlite3_compileoption_get() may be omitted by specifying the
377** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
379** See also: SQL functions [sqlite_compileoption_used()] and
380** [sqlite_compileoption_get()] and the [compile_options pragma].
383SQLITE_API int SQLITE_STDCALL sqlite3_compileoption_used(const char *zOptName);
384SQLITE_API const char *SQLITE_STDCALL sqlite3_compileoption_get(int N);
388** CAPI3REF: Test To See If The Library Is Threadsafe
390** ^The sqlite3_threadsafe() function returns zero if and only if
391** SQLite was compiled with mutexing code omitted due to the
392** [SQLITE_THREADSAFE] compile-time option being set to 0.
394** SQLite can be compiled with or without mutexes.  When
395** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
396** are enabled and SQLite is threadsafe.  When the
397** [SQLITE_THREADSAFE] macro is 0,
398** the mutexes are omitted.  Without the mutexes, it is not safe
399** to use SQLite concurrently from more than one thread.
401** Enabling mutexes incurs a measurable performance penalty.
402** So if speed is of utmost importance, it makes sense to disable
403** the mutexes.  But for maximum safety, mutexes should be enabled.
404** ^The default behavior is for mutexes to be enabled.
406** This interface can be used by an application to make sure that the
407** version of SQLite that it is linking against was compiled with
408** the desired setting of the [SQLITE_THREADSAFE] macro.
410** This interface only reports on the compile-time mutex setting
411** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
412** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
413** can be fully or partially disabled using a call to [sqlite3_config()]
415** or [SQLITE_CONFIG_SERIALIZED].  ^(The return value of the
416** sqlite3_threadsafe() function shows only the compile-time setting of
417** thread safety, not any run-time changes to that setting made by
418** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
419** is unchanged by calls to sqlite3_config().)^
421** See the [threading mode] documentation for additional information.
423SQLITE_API int SQLITE_STDCALL sqlite3_threadsafe(void);
426** CAPI3REF: Database Connection Handle
427** KEYWORDS: {database connection} {database connections}
429** Each open SQLite database is represented by a pointer to an instance of
430** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
431** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
432** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
433** and [sqlite3_close_v2()] are its destructors.  There are many other
434** interfaces (such as
435** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
436** [sqlite3_busy_timeout()] to name but three) that are methods on an
437** sqlite3 object.
439typedef struct sqlite3 sqlite3;
442** CAPI3REF: 64-Bit Integer Types
443** KEYWORDS: sqlite_int64 sqlite_uint64
445** Because there is no cross-platform way to specify 64-bit integer types
446** SQLite includes typedefs for 64-bit signed and unsigned integers.
448** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
449** The sqlite_int64 and sqlite_uint64 types are supported for backwards
450** compatibility only.
452** ^The sqlite3_int64 and sqlite_int64 types can store integer values
453** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
454** sqlite3_uint64 and sqlite_uint64 types can store integer values
455** between 0 and +18446744073709551615 inclusive.
457#ifdef SQLITE_INT64_TYPE
458  typedef SQLITE_INT64_TYPE sqlite_int64;
459  typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
460#elif defined(_MSC_VER) || defined(__BORLANDC__)
461  typedef __int64 sqlite_int64;
462  typedef unsigned __int64 sqlite_uint64;
464  typedef long long int sqlite_int64;
465  typedef unsigned long long int sqlite_uint64;
467typedef sqlite_int64 sqlite3_int64;
468typedef sqlite_uint64 sqlite3_uint64;
471** If compiling for a processor that lacks floating point support,
472** substitute integer for floating-point.
475# define double sqlite3_int64
479** CAPI3REF: Closing A Database Connection
480** DESTRUCTOR: sqlite3
482** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
483** for the [sqlite3] object.
484** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
485** the [sqlite3] object is successfully destroyed and all associated
486** resources are deallocated.
488** ^If the database connection is associated with unfinalized prepared
489** statements or unfinished sqlite3_backup objects then sqlite3_close()
490** will leave the database connection open and return [SQLITE_BUSY].
491** ^If sqlite3_close_v2() is called with unfinalized prepared statements
492** and/or unfinished sqlite3_backups, then the database connection becomes
493** an unusable "zombie" which will automatically be deallocated when the
494** last prepared statement is finalized or the last sqlite3_backup is
495** finished.  The sqlite3_close_v2() interface is intended for use with
496** host languages that are garbage collected, and where the order in which
497** destructors are called is arbitrary.
499** Applications should [sqlite3_finalize | finalize] all [prepared statements],
500** [sqlite3_blob_close | close] all [BLOB handles], and
501** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
502** with the [sqlite3] object prior to attempting to close the object.  ^If
503** sqlite3_close_v2() is called on a [database connection] that still has
504** outstanding [prepared statements], [BLOB handles], and/or
505** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
506** of resources is deferred until all [prepared statements], [BLOB handles],
507** and [sqlite3_backup] objects are also destroyed.
509** ^If an [sqlite3] object is destroyed while a transaction is open,
510** the transaction is automatically rolled back.
512** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
513** must be either a NULL
514** pointer or an [sqlite3] object pointer obtained
515** from [sqlite3_open()], [sqlite3_open16()], or
516** [sqlite3_open_v2()], and not previously closed.
517** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
518** argument is a harmless no-op.
520SQLITE_API int SQLITE_STDCALL sqlite3_close(sqlite3*);
521SQLITE_API int SQLITE_STDCALL sqlite3_close_v2(sqlite3*);
524** The type for a callback function.
525** This is legacy and deprecated.  It is included for historical
526** compatibility and is not documented.
528typedef int (*sqlite3_callback)(void*,int,char**, char**);
531** CAPI3REF: One-Step Query Execution Interface
532** METHOD: sqlite3
534** The sqlite3_exec() interface is a convenience wrapper around
535** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
536** that allows an application to run multiple statements of SQL
537** without having to use a lot of C code.
539** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
540** semicolon-separate SQL statements passed into its 2nd argument,
541** in the context of the [database connection] passed in as its 1st
542** argument.  ^If the callback function of the 3rd argument to
543** sqlite3_exec() is not NULL, then it is invoked for each result row
544** coming out of the evaluated SQL statements.  ^The 4th argument to
545** sqlite3_exec() is relayed through to the 1st argument of each
546** callback invocation.  ^If the callback pointer to sqlite3_exec()
547** is NULL, then no callback is ever invoked and result rows are
548** ignored.
550** ^If an error occurs while evaluating the SQL statements passed into
551** sqlite3_exec(), then execution of the current statement stops and
552** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
553** is not NULL then any error message is written into memory obtained
554** from [sqlite3_malloc()] and passed back through the 5th parameter.
555** To avoid memory leaks, the application should invoke [sqlite3_free()]
556** on error message strings returned through the 5th parameter of
557** of sqlite3_exec() after the error message string is no longer needed.
558** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
559** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
560** NULL before returning.
562** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
563** routine returns SQLITE_ABORT without invoking the callback again and
564** without running any subsequent SQL statements.
566** ^The 2nd argument to the sqlite3_exec() callback function is the
567** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
568** callback is an array of pointers to strings obtained as if from
569** [sqlite3_column_text()], one for each column.  ^If an element of a
570** result row is NULL then the corresponding string pointer for the
571** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
572** sqlite3_exec() callback is an array of pointers to strings where each
573** entry represents the name of corresponding result column as obtained
574** from [sqlite3_column_name()].
576** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
577** to an empty string, or a pointer that contains only whitespace and/or
578** SQL comments, then no SQL statements are evaluated and the database
579** is not changed.
581** Restrictions:
583** <ul>
584** <li> The application must insure that the 1st parameter to sqlite3_exec()
585**      is a valid and open [database connection].
586** <li> The application must not close the [database connection] specified by
587**      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
588** <li> The application must not modify the SQL statement text passed into
589**      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
590** </ul>
592SQLITE_API int SQLITE_STDCALL sqlite3_exec(
593  sqlite3*,                                  /* An open database */
594  const char *sql,                           /* SQL to be evaluated */
595  int (*callback)(void*,int,char**,char**),  /* Callback function */
596  void *,                                    /* 1st argument to callback */
597  char **errmsg                              /* Error msg written here */
601** CAPI3REF: Result Codes
602** KEYWORDS: {result code definitions}
604** Many SQLite functions return an integer result code from the set shown
605** here in order to indicate success or failure.
607** New error codes may be added in future versions of SQLite.
609** See also: [extended result code definitions]
611#define SQLITE_OK           0   /* Successful result */
612/* beginning-of-error-codes */
613#define SQLITE_ERROR        1   /* SQL error or missing database */
614#define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
615#define SQLITE_PERM         3   /* Access permission denied */
616#define SQLITE_ABORT        4   /* Callback routine requested an abort */
617#define SQLITE_BUSY         5   /* The database file is locked */
618#define SQLITE_LOCKED       6   /* A table in the database is locked */
619#define SQLITE_NOMEM        7   /* A malloc() failed */
620#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
621#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
622#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
623#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
624#define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
625#define SQLITE_FULL        13   /* Insertion failed because database is full */
626#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
627#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
628#define SQLITE_EMPTY       16   /* Database is empty */
629#define SQLITE_SCHEMA      17   /* The database schema changed */
630#define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
631#define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
632#define SQLITE_MISMATCH    20   /* Data type mismatch */
633#define SQLITE_MISUSE      21   /* Library used incorrectly */
634#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
635#define SQLITE_AUTH        23   /* Authorization denied */
636#define SQLITE_FORMAT      24   /* Auxiliary database format error */
637#define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
638#define SQLITE_NOTADB      26   /* File opened that is not a database file */
639#define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
640#define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
641#define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
642#define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
643/* end-of-error-codes */
646** CAPI3REF: Extended Result Codes
647** KEYWORDS: {extended result code definitions}
649** In its default configuration, SQLite API routines return one of 30 integer
650** [result codes].  However, experience has shown that many of
651** these result codes are too coarse-grained.  They do not provide as
652** much information about problems as programmers might like.  In an effort to
653** address this, newer versions of SQLite (version 3.3.8 and later) include
654** support for additional result codes that provide more detailed information
655** about errors. These [extended result codes] are enabled or disabled
656** on a per database connection basis using the
657** [sqlite3_extended_result_codes()] API.  Or, the extended code for
658** the most recent error can be obtained using
659** [sqlite3_extended_errcode()].
661#define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
662#define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
663#define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
664#define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
665#define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
666#define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
667#define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
668#define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
669#define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
670#define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
671#define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
672#define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
673#define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
675#define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
676#define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
677#define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
678#define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
679#define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
680#define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
681#define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
682#define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
683#define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
684#define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
685#define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
686#define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
688#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
689#define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
691#define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
694#define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
699#define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
713#define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
716** CAPI3REF: Flags For File Open Operations
718** These bit values are intended for use in the
719** 3rd parameter to the [sqlite3_open_v2()] interface and
720** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
722#define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
723#define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
724#define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
725#define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
726#define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
727#define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
728#define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
729#define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
730#define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
731#define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
732#define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
733#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
734#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
735#define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
736#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
737#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
738#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
739#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
740#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
741#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
743/* Reserved:                         0x00F00000 */
746** CAPI3REF: Device Characteristics
748** The xDeviceCharacteristics method of the [sqlite3_io_methods]
749** object returns an integer which is a vector of these
750** bit values expressing I/O characteristics of the mass storage
751** device that holds the file that the [sqlite3_io_methods]
752** refers to.
754** The SQLITE_IOCAP_ATOMIC property means that all writes of
755** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
756** mean that writes of blocks that are nnn bytes in size and
757** are aligned to an address which is an integer multiple of
758** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
759** that when data is appended to a file, the data is appended
760** first then the size of the file is extended, never the other
761** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
762** information is written to disk in the same order as calls
763** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
764** after reboot following a crash or power loss, the only bytes in a
765** file that were written at the application level might have changed
766** and that adjacent bytes, even bytes within the same sector are
767** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
768** flag indicate that a file cannot be deleted when open.  The
769** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
770** read-only media and cannot be changed even by processes with
771** elevated privileges.
773#define SQLITE_IOCAP_ATOMIC                 0x00000001
774#define SQLITE_IOCAP_ATOMIC512              0x00000002
775#define SQLITE_IOCAP_ATOMIC1K               0x00000004
776#define SQLITE_IOCAP_ATOMIC2K               0x00000008
777#define SQLITE_IOCAP_ATOMIC4K               0x00000010
778#define SQLITE_IOCAP_ATOMIC8K               0x00000020
779#define SQLITE_IOCAP_ATOMIC16K              0x00000040
780#define SQLITE_IOCAP_ATOMIC32K              0x00000080
781#define SQLITE_IOCAP_ATOMIC64K              0x00000100
782#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
783#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
786#define SQLITE_IOCAP_IMMUTABLE              0x00002000
789** CAPI3REF: File Locking Levels
791** SQLite uses one of these integer values as the second
792** argument to calls it makes to the xLock() and xUnlock() methods
793** of an [sqlite3_io_methods] object.
795#define SQLITE_LOCK_NONE          0
796#define SQLITE_LOCK_SHARED        1
797#define SQLITE_LOCK_RESERVED      2
798#define SQLITE_LOCK_PENDING       3
799#define SQLITE_LOCK_EXCLUSIVE     4
802** CAPI3REF: Synchronization Type Flags
804** When SQLite invokes the xSync() method of an
805** [sqlite3_io_methods] object it uses a combination of
806** these integer values as the second argument.
808** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
809** sync operation only needs to flush data to mass storage.  Inode
810** information need not be flushed. If the lower four bits of the flag
811** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
812** If the lower four bits equal SQLITE_SYNC_FULL, that means
813** to use Mac OS X style fullsync instead of fsync().
815** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
816** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
817** settings.  The [synchronous pragma] determines when calls to the
818** xSync VFS method occur and applies uniformly across all platforms.
819** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
820** energetic or rigorous or forceful the sync operations are and
821** only make a difference on Mac OSX for the default SQLite code.
822** (Third-party VFS implementations might also make the distinction
823** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
824** operating systems natively supported by SQLite, only Mac OSX
825** cares about the difference.)
827#define SQLITE_SYNC_NORMAL        0x00002
828#define SQLITE_SYNC_FULL          0x00003
829#define SQLITE_SYNC_DATAONLY      0x00010
832** CAPI3REF: OS Interface Open File Handle
834** An [sqlite3_file] object represents an open file in the
835** [sqlite3_vfs | OS interface layer].  Individual OS interface
836** implementations will
837** want to subclass this object by appending additional fields
838** for their own use.  The pMethods entry is a pointer to an
839** [sqlite3_io_methods] object that defines methods for performing
840** I/O operations on the open file.
842typedef struct sqlite3_file sqlite3_file;
843struct sqlite3_file {
844  const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
848** CAPI3REF: OS Interface File Virtual Methods Object
850** Every file opened by the [sqlite3_vfs.xOpen] method populates an
851** [sqlite3_file] object (or, more commonly, a subclass of the
852** [sqlite3_file] object) with a pointer to an instance of this object.
853** This object defines the methods used to perform various operations
854** against the open file represented by the [sqlite3_file] object.
856** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
857** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
858** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
859** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
860** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
861** to NULL.
863** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
864** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
865** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
866** flag may be ORed in to indicate that only the data of the file
867** and not its inode needs to be synced.
869** The integer values to xLock() and xUnlock() are one of
870** <ul>
871** <li> [SQLITE_LOCK_NONE],
872** <li> [SQLITE_LOCK_SHARED],
874** <li> [SQLITE_LOCK_PENDING], or
876** </ul>
877** xLock() increases the lock. xUnlock() decreases the lock.
878** The xCheckReservedLock() method checks whether any database connection,
879** either in this process or in some other process, is holding a RESERVED,
880** PENDING, or EXCLUSIVE lock on the file.  It returns true
881** if such a lock exists and false otherwise.
883** The xFileControl() method is a generic interface that allows custom
884** VFS implementations to directly control an open file using the
885** [sqlite3_file_control()] interface.  The second "op" argument is an
886** integer opcode.  The third argument is a generic pointer intended to
887** point to a structure that may contain arguments or space in which to
888** write return values.  Potential uses for xFileControl() might be
889** functions to enable blocking locks with timeouts, to change the
890** locking strategy (for example to use dot-file locks), to inquire
891** about the status of a lock, or to break stale locks.  The SQLite
892** core reserves all opcodes less than 100 for its own use.
893** A [file control opcodes | list of opcodes] less than 100 is available.
894** Applications that define a custom xFileControl method should use opcodes
895** greater than 100 to avoid conflicts.  VFS implementations should
896** return [SQLITE_NOTFOUND] for file control opcodes that they do not
897** recognize.
899** The xSectorSize() method returns the sector size of the
900** device that underlies the file.  The sector size is the
901** minimum write that can be performed without disturbing
902** other bytes in the file.  The xDeviceCharacteristics()
903** method returns a bit vector describing behaviors of the
904** underlying device:
906** <ul>
908** <li> [SQLITE_IOCAP_ATOMIC512]
918** </ul>
920** The SQLITE_IOCAP_ATOMIC property means that all writes of
921** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
922** mean that writes of blocks that are nnn bytes in size and
923** are aligned to an address which is an integer multiple of
924** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
925** that when data is appended to a file, the data is appended
926** first then the size of the file is extended, never the other
927** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
928** information is written to disk in the same order as calls
929** to xWrite().
931** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
932** in the unread portions of the buffer with zeros.  A VFS that
933** fails to zero-fill short reads might seem to work.  However,
934** failure to zero-fill short reads will eventually lead to
935** database corruption.
937typedef struct sqlite3_io_methods sqlite3_io_methods;
938struct sqlite3_io_methods {
939  int iVersion;
940  int (*xClose)(sqlite3_file*);
941  int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
942  int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
943  int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
944  int (*xSync)(sqlite3_file*, int flags);
945  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
946  int (*xLock)(sqlite3_file*, int);
947  int (*xUnlock)(sqlite3_file*, int);
948  int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
949  int (*xFileControl)(sqlite3_file*, int op, void *pArg);
950  int (*xSectorSize)(sqlite3_file*);
951  int (*xDeviceCharacteristics)(sqlite3_file*);
952  /* Methods above are valid for version 1 */
953  int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
954  int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
955  void (*xShmBarrier)(sqlite3_file*);
956  int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
957  /* Methods above are valid for version 2 */
958  int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
959  int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
960  /* Methods above are valid for version 3 */
961  /* Additional methods may be added in future releases */
965** CAPI3REF: Standard File Control Opcodes
966** KEYWORDS: {file control opcodes} {file control opcode}
968** These integer constants are opcodes for the xFileControl method
969** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
970** interface.
972** <ul>
974** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
975** opcode causes the xFileControl method to write the current state of
976** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
978** into an integer that the pArg argument points to. This capability
979** is used during testing and is only available when the SQLITE_TEST
980** compile-time option is used.
983** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
984** layer a hint of how large the database file will grow to be during the
985** current transaction.  This hint is not guaranteed to be accurate but it
986** is often close.  The underlying VFS might choose to preallocate database
987** file space based on this hint in order to help writes to the database
988** file run faster.
991** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
992** extends and truncates the database file in chunks of a size specified
993** by the user. The fourth argument to [sqlite3_file_control()] should
994** point to an integer (type int) containing the new chunk-size to use
995** for the nominated database. Allocating database file space in large
996** chunks (say 1MB at a time), may reduce file-system fragmentation and
997** improve performance on some systems.
1000** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
1001** to the [sqlite3_file] object associated with a particular database
1002** connection.  See the [sqlite3_file_control()] documentation for
1003** additional information.
1006** No longer in use.
1008** <li>[[SQLITE_FCNTL_SYNC]]
1009** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
1010** sent to the VFS immediately before the xSync method is invoked on a
1011** database file descriptor. Or, if the xSync method is not invoked
1012** because the user has configured SQLite with
1013** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
1014** of the xSync method. In most cases, the pointer argument passed with
1015** this file-control is NULL. However, if the database file is being synced
1016** as part of a multi-database commit, the argument points to a nul-terminated
1017** string containing the transactions master-journal file name. VFSes that
1018** do not need this signal should silently ignore this opcode. Applications
1019** should not call [sqlite3_file_control()] with this opcode as doing so may
1020** disrupt the operation of the specialized VFSes that do require it.
1023** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
1024** and sent to the VFS after a transaction has been committed immediately
1025** but before the database is unlocked. VFSes that do not need this signal
1026** should silently ignore this opcode. Applications should not call
1027** [sqlite3_file_control()] with this opcode as doing so may disrupt the
1028** operation of the specialized VFSes that do require it.
1030** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
1031** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
1032** retry counts and intervals for certain disk I/O operations for the
1033** windows [VFS] in order to provide robustness in the presence of
1034** anti-virus programs.  By default, the windows VFS will retry file read,
1035** file write, and file delete operations up to 10 times, with a delay
1036** of 25 milliseconds before the first retry and with the delay increasing
1037** by an additional 25 milliseconds with each subsequent retry.  This
1038** opcode allows these two values (10 retries and 25 milliseconds of delay)
1039** to be adjusted.  The values are changed for all database connections
1040** within the same process.  The argument is a pointer to an array of two
1041** integers where the first integer i the new retry count and the second
1042** integer is the delay.  If either integer is negative, then the setting
1043** is not changed but instead the prior value of that setting is written
1044** into the array entry, allowing the current retry settings to be
1045** interrogated.  The zDbName parameter is ignored.
1048** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
1049** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
1050** write ahead log and shared memory files used for transaction control
1051** are automatically deleted when the latest connection to the database
1052** closes.  Setting persistent WAL mode causes those files to persist after
1053** close.  Persisting the files is useful when other processes that do not
1054** have write permission on the directory containing the database file want
1055** to read the database file, as the WAL and shared memory files must exist
1056** in order for the database to be readable.  The fourth parameter to
1057** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
1058** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
1059** WAL mode.  If the integer is -1, then it is overwritten with the current
1060** WAL persistence setting.
1063** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
1064** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
1065** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
1066** xDeviceCharacteristics methods. The fourth parameter to
1067** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
1068** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
1069** mode.  If the integer is -1, then it is overwritten with the current
1070** zero-damage mode setting.
1073** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
1074** a write transaction to indicate that, unless it is rolled back for some
1075** reason, the entire database file will be overwritten by the current
1076** transaction. This is used by VACUUM operations.
1079** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
1080** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
1081** final bottom-level VFS are written into memory obtained from
1082** [sqlite3_malloc()] and the result is stored in the char* variable
1083** that the fourth parameter of [sqlite3_file_control()] points to.
1084** The caller is responsible for freeing the memory when done.  As with
1085** all file-control actions, there is no guarantee that this will actually
1086** do anything.  Callers should initialize the char* variable to a NULL
1087** pointer in case this file-control is not implemented.  This file-control
1088** is intended for diagnostic use only.
1090** <li>[[SQLITE_FCNTL_PRAGMA]]
1091** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
1092** file control is sent to the open [sqlite3_file] object corresponding
1093** to the database file to which the pragma statement refers. ^The argument
1094** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
1095** pointers to strings (char**) in which the second element of the array
1096** is the name of the pragma and the third element is the argument to the
1097** pragma or NULL if the pragma has no argument.  ^The handler for an
1098** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
1099** of the char** argument point to a string obtained from [sqlite3_mprintf()]
1100** or the equivalent and that string will become the result of the pragma or
1101** the error message if the pragma fails. ^If the
1102** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
1103** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
1104** file control returns [SQLITE_OK], then the parser assumes that the
1105** VFS has handled the PRAGMA itself and the parser generates a no-op
1106** prepared statement if result string is NULL, or that returns a copy
1107** of the result string if the string is non-NULL.
1108** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
1109** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
1110** that the VFS encountered an error while handling the [PRAGMA] and the
1111** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
1112** file control occurs at the beginning of pragma statement analysis and so
1113** it is able to override built-in [PRAGMA] statements.
1117** file-control may be invoked by SQLite on the database file handle
1118** shortly after it is opened in order to provide a custom VFS with access
1119** to the connections busy-handler callback. The argument is of type (void **)
1120** - an array of two (void *) values. The first (void *) actually points
1121** to a function of type (int (*)(void *)). In order to invoke the connections
1122** busy-handler, this function should be invoked with the second (void *) in
1123** the array as the only argument. If it returns non-zero, then the operation
1124** should be retried. If it returns zero, the custom VFS should abandon the
1125** current operation.
1128** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
1129** to have SQLite generate a
1130** temporary filename using the same algorithm that is followed to generate
1131** temporary filenames for TEMP tables and other internal uses.  The
1132** argument should be a char** which will be filled with the filename
1133** written into memory obtained from [sqlite3_malloc()].  The caller should
1134** invoke [sqlite3_free()] on the result to avoid a memory leak.
1137** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
1138** maximum number of bytes that will be used for memory-mapped I/O.
1139** The argument is a pointer to a value of type sqlite3_int64 that
1140** is an advisory maximum number of bytes in the file to memory map.  The
1141** pointer is overwritten with the old value.  The limit is not changed if
1142** the value originally pointed to is negative, and so the current limit
1143** can be queried by passing in a pointer to a negative number.  This
1144** file-control is used internally to implement [PRAGMA mmap_size].
1146** <li>[[SQLITE_FCNTL_TRACE]]
1147** The [SQLITE_FCNTL_TRACE] file control provides advisory information
1148** to the VFS about what the higher layers of the SQLite stack are doing.
1149** This file control is used by some VFS activity tracing [shims].
1150** The argument is a zero-terminated string.  Higher layers in the
1151** SQLite stack may generate instances of this file control if
1152** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
1155** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
1156** pointer to an integer and it writes a boolean into that integer depending
1157** on whether or not the file has been renamed, moved, or deleted since it
1158** was first opened.
1161** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
1162** opcode causes the xFileControl method to swap the file handle with the one
1163** pointed to by the pArg argument.  This capability is used during testing
1164** and only needs to be supported when SQLITE_TEST is defined.
1167** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
1168** be advantageous to block on the next WAL lock if the lock is not immediately
1169** available.  The WAL subsystem issues this signal during rare
1170** circumstances in order to fix a problem with priority inversion.
1171** Applications should <em>not</em> use this file-control.
1173** </ul>
1175#define SQLITE_FCNTL_LOCKSTATE               1
1178#define SQLITE_FCNTL_LAST_ERRNO              4
1179#define SQLITE_FCNTL_SIZE_HINT               5
1180#define SQLITE_FCNTL_CHUNK_SIZE              6
1181#define SQLITE_FCNTL_FILE_POINTER            7
1182#define SQLITE_FCNTL_SYNC_OMITTED            8
1183#define SQLITE_FCNTL_WIN32_AV_RETRY          9
1184#define SQLITE_FCNTL_PERSIST_WAL            10
1185#define SQLITE_FCNTL_OVERWRITE              11
1186#define SQLITE_FCNTL_VFSNAME                12
1188#define SQLITE_FCNTL_PRAGMA                 14
1189#define SQLITE_FCNTL_BUSYHANDLER            15
1190#define SQLITE_FCNTL_TEMPFILENAME           16
1191#define SQLITE_FCNTL_MMAP_SIZE              18
1192#define SQLITE_FCNTL_TRACE                  19
1193#define SQLITE_FCNTL_HAS_MOVED              20
1194#define SQLITE_FCNTL_SYNC                   21
1195#define SQLITE_FCNTL_COMMIT_PHASETWO        22
1196#define SQLITE_FCNTL_WIN32_SET_HANDLE       23
1197#define SQLITE_FCNTL_WAL_BLOCK              24
1199/* deprecated names */
1206** CAPI3REF: Mutex Handle
1208** The mutex module within SQLite defines [sqlite3_mutex] to be an
1209** abstract type for a mutex object.  The SQLite core never looks
1210** at the internal representation of an [sqlite3_mutex].  It only
1211** deals with pointers to the [sqlite3_mutex] object.
1213** Mutexes are created using [sqlite3_mutex_alloc()].
1215typedef struct sqlite3_mutex sqlite3_mutex;
1218** CAPI3REF: OS Interface Object
1220** An instance of the sqlite3_vfs object defines the interface between
1221** the SQLite core and the underlying operating system.  The "vfs"
1222** in the name of the object stands for "virtual file system".  See
1223** the [VFS | VFS documentation] for further information.
1225** The value of the iVersion field is initially 1 but may be larger in
1226** future versions of SQLite.  Additional fields may be appended to this
1227** object when the iVersion value is increased.  Note that the structure
1228** of the sqlite3_vfs object changes in the transaction between
1229** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
1230** modified.
1232** The szOsFile field is the size of the subclassed [sqlite3_file]
1233** structure used by this VFS.  mxPathname is the maximum length of
1234** a pathname in this VFS.
1236** Registered sqlite3_vfs objects are kept on a linked list formed by
1237** the pNext pointer.  The [sqlite3_vfs_register()]
1238** and [sqlite3_vfs_unregister()] interfaces manage this list
1239** in a thread-safe way.  The [sqlite3_vfs_find()] interface
1240** searches the list.  Neither the application code nor the VFS
1241** implementation should use the pNext pointer.
1243** The pNext field is the only field in the sqlite3_vfs
1244** structure that SQLite will ever modify.  SQLite will only access
1245** or modify this field while holding a particular static mutex.
1246** The application should never modify anything within the sqlite3_vfs
1247** object once the object has been registered.
1249** The zName field holds the name of the VFS module.  The name must
1250** be unique across all VFS modules.
1252** [[sqlite3_vfs.xOpen]]
1253** ^SQLite guarantees that the zFilename parameter to xOpen
1254** is either a NULL pointer or string obtained
1255** from xFullPathname() with an optional suffix added.
1256** ^If a suffix is added to the zFilename parameter, it will
1257** consist of a single "-" character followed by no more than
1258** 11 alphanumeric and/or "-" characters.
1259** ^SQLite further guarantees that
1260** the string will be valid and unchanged until xClose() is
1261** called. Because of the previous sentence,
1262** the [sqlite3_file] can safely store a pointer to the
1263** filename if it needs to remember the filename for some reason.
1264** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1265** must invent its own temporary name for the file.  ^Whenever the
1266** xFilename parameter is NULL it will also be the case that the
1267** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1269** The flags argument to xOpen() includes all bits set in
1270** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
1271** or [sqlite3_open16()] is used, then flags includes at least
1273** If xOpen() opens a file read-only then it sets *pOutFlags to
1274** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
1276** ^(SQLite will also add one of the following flags to the xOpen()
1277** call, depending on the object being opened:
1279** <ul>
1280** <li>  [SQLITE_OPEN_MAIN_DB]
1282** <li>  [SQLITE_OPEN_TEMP_DB]
1287** <li>  [SQLITE_OPEN_WAL]
1288** </ul>)^
1290** The file I/O implementation can use the object type flags to
1291** change the way it deals with files.  For example, an application
1292** that does not care about crash recovery or rollback might make
1293** the open of a journal file a no-op.  Writes to this journal would
1294** also be no-ops, and any attempt to read the journal would return
1295** SQLITE_IOERR.  Or the implementation might recognize that a database
1296** file will be doing page-aligned sector reads and writes in a random
1297** order and set up its I/O subsystem accordingly.
1299** SQLite might also add one of the following flags to the xOpen method:
1301** <ul>
1304** </ul>
1306** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1307** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
1308** will be set for TEMP databases and their journals, transient
1309** databases, and subjournals.
1311** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1312** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1313** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1314** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1315** SQLITE_OPEN_CREATE, is used to indicate that file should always
1316** be created, and that it is an error if it already exists.
1317** It is <i>not</i> used to indicate the file should be opened
1318** for exclusive access.
1320** ^At least szOsFile bytes of memory are allocated by SQLite
1321** to hold the  [sqlite3_file] structure passed as the third
1322** argument to xOpen.  The xOpen method does not have to
1323** allocate the structure; it should just fill it in.  Note that
1324** the xOpen method must set the sqlite3_file.pMethods to either
1325** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
1326** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
1327** element will be valid after xOpen returns regardless of the success
1328** or failure of the xOpen call.
1330** [[sqlite3_vfs.xAccess]]
1331** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1332** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1333** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1334** to test whether a file is at least readable.   The file can be a
1335** directory.
1337** ^SQLite will always allocate at least mxPathname+1 bytes for the
1338** output buffer xFullPathname.  The exact size of the output buffer
1339** is also passed as a parameter to both  methods. If the output buffer
1340** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1341** handled as a fatal error by SQLite, vfs implementations should endeavor
1342** to prevent this by setting mxPathname to a sufficiently large value.
1344** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1345** interfaces are not strictly a part of the filesystem, but they are
1346** included in the VFS structure for completeness.
1347** The xRandomness() function attempts to return nBytes bytes
1348** of good-quality randomness into zOut.  The return value is
1349** the actual number of bytes of randomness obtained.
1350** The xSleep() method causes the calling thread to sleep for at
1351** least the number of microseconds given.  ^The xCurrentTime()
1352** method returns a Julian Day Number for the current date and time as
1353** a floating point value.
1354** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1355** Day Number multiplied by 86400000 (the number of milliseconds in
1356** a 24-hour day).
1357** ^SQLite will use the xCurrentTimeInt64() method to get the current
1358** date and time if that method is available (if iVersion is 2 or
1359** greater and the function pointer is not NULL) and will fall back
1360** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1362** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1363** are not used by the SQLite core.  These optional interfaces are provided
1364** by some VFSes to facilitate testing of the VFS code. By overriding
1365** system calls with functions under its control, a test program can
1366** simulate faults and error conditions that would otherwise be difficult
1367** or impossible to induce.  The set of system calls that can be overridden
1368** varies from one VFS to another, and from one version of the same VFS to the
1369** next.  Applications that use these interfaces must be prepared for any
1370** or all of these interfaces to be NULL or for their behavior to change
1371** from one release to the next.  Applications must not attempt to access
1372** any of these methods if the iVersion of the VFS is less than 3.
1374typedef struct sqlite3_vfs sqlite3_vfs;
1375typedef void (*sqlite3_syscall_ptr)(void);
1376struct sqlite3_vfs {
1377  int iVersion;            /* Structure version number (currently 3) */
1378  int szOsFile;            /* Size of subclassed sqlite3_file */
1379  int mxPathname;          /* Maximum file pathname length */
1380  sqlite3_vfs *pNext;      /* Next registered VFS */
1381  const char *zName;       /* Name of this virtual file system */
1382  void *pAppData;          /* Pointer to application-specific data */
1383  int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1384               int flags, int *pOutFlags);
1385  int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1386  int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1387  int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1388  void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1389  void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1390  void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1391  void (*xDlClose)(sqlite3_vfs*, void*);
1392  int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1393  int (*xSleep)(sqlite3_vfs*, int microseconds);
1394  int (*xCurrentTime)(sqlite3_vfs*, double*);
1395  int (*xGetLastError)(sqlite3_vfs*, int, char *);
1396  /*
1397  ** The methods above are in version 1 of the sqlite_vfs object
1398  ** definition.  Those that follow are added in version 2 or later
1399  */
1400  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1401  /*
1402  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1403  ** Those below are for version 3 and greater.
1404  */
1405  int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1406  sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1407  const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1408  /*
1409  ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1410  ** New fields may be appended in figure versions.  The iVersion
1411  ** value will increment whenever this happens.
1412  */
1416** CAPI3REF: Flags for the xAccess VFS method
1418** These integer constants can be used as the third parameter to
1419** the xAccess method of an [sqlite3_vfs] object.  They determine
1420** what kind of permissions the xAccess method is looking for.
1421** With SQLITE_ACCESS_EXISTS, the xAccess method
1422** simply checks whether the file exists.
1423** With SQLITE_ACCESS_READWRITE, the xAccess method
1424** checks whether the named directory is both readable and writable
1425** (in other words, if files can be added, removed, and renamed within
1426** the directory).
1427** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1428** [temp_store_directory pragma], though this could change in a future
1429** release of SQLite.
1430** With SQLITE_ACCESS_READ, the xAccess method
1431** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
1432** currently unused, though it might be used in a future release of
1433** SQLite.
1435#define SQLITE_ACCESS_EXISTS    0
1436#define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
1437#define SQLITE_ACCESS_READ      2   /* Unused */
1440** CAPI3REF: Flags for the xShmLock VFS method
1442** These integer constants define the various locking operations
1443** allowed by the xShmLock method of [sqlite3_io_methods].  The
1444** following are the only legal combinations of flags to the
1445** xShmLock method:
1447** <ul>
1452** </ul>
1454** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1455** was given on the corresponding lock.
1457** The xShmLock method can transition between unlocked and SHARED or
1458** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
1459** and EXCLUSIVE.
1461#define SQLITE_SHM_UNLOCK       1
1462#define SQLITE_SHM_LOCK         2
1463#define SQLITE_SHM_SHARED       4
1464#define SQLITE_SHM_EXCLUSIVE    8
1467** CAPI3REF: Maximum xShmLock index
1469** The xShmLock method on [sqlite3_io_methods] may use values
1470** between 0 and this upper bound as its "offset" argument.
1471** The SQLite core will never attempt to acquire or release a
1472** lock outside of this range
1474#define SQLITE_SHM_NLOCK        8
1478** CAPI3REF: Initialize The SQLite Library
1480** ^The sqlite3_initialize() routine initializes the
1481** SQLite library.  ^The sqlite3_shutdown() routine
1482** deallocates any resources that were allocated by sqlite3_initialize().
1483** These routines are designed to aid in process initialization and
1484** shutdown on embedded systems.  Workstation applications using
1485** SQLite normally do not need to invoke either of these routines.
1487** A call to sqlite3_initialize() is an "effective" call if it is
1488** the first time sqlite3_initialize() is invoked during the lifetime of
1489** the process, or if it is the first time sqlite3_initialize() is invoked
1490** following a call to sqlite3_shutdown().  ^(Only an effective call
1491** of sqlite3_initialize() does any initialization.  All other calls
1492** are harmless no-ops.)^
1494** A call to sqlite3_shutdown() is an "effective" call if it is the first
1495** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
1496** an effective call to sqlite3_shutdown() does any deinitialization.
1497** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1499** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1500** is not.  The sqlite3_shutdown() interface must only be called from a
1501** single thread.  All open [database connections] must be closed and all
1502** other SQLite resources must be deallocated prior to invoking
1503** sqlite3_shutdown().
1505** Among other things, ^sqlite3_initialize() will invoke
1506** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
1507** will invoke sqlite3_os_end().
1509** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1510** ^If for some reason, sqlite3_initialize() is unable to initialize
1511** the library (perhaps it is unable to allocate a needed resource such
1512** as a mutex) it returns an [error code] other than [SQLITE_OK].
1514** ^The sqlite3_initialize() routine is called internally by many other
1515** SQLite interfaces so that an application usually does not need to
1516** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
1517** calls sqlite3_initialize() so the SQLite library will be automatically
1518** initialized when [sqlite3_open()] is called if it has not be initialized
1519** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1520** compile-time option, then the automatic calls to sqlite3_initialize()
1521** are omitted and the application must call sqlite3_initialize() directly
1522** prior to using any other SQLite interface.  For maximum portability,
1523** it is recommended that applications always invoke sqlite3_initialize()
1524** directly prior to using any other SQLite interface.  Future releases
1525** of SQLite may require this.  In other words, the behavior exhibited
1526** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1527** default behavior in some future release of SQLite.
1529** The sqlite3_os_init() routine does operating-system specific
1530** initialization of the SQLite library.  The sqlite3_os_end()
1531** routine undoes the effect of sqlite3_os_init().  Typical tasks
1532** performed by these routines include allocation or deallocation
1533** of static resources, initialization of global variables,
1534** setting up a default [sqlite3_vfs] module, or setting up
1535** a default configuration using [sqlite3_config()].
1537** The application should never invoke either sqlite3_os_init()
1538** or sqlite3_os_end() directly.  The application should only invoke
1539** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
1540** interface is called automatically by sqlite3_initialize() and
1541** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
1542** implementations for sqlite3_os_init() and sqlite3_os_end()
1543** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1544** When [custom builds | built for other platforms]
1545** (using the [SQLITE_OS_OTHER=1] compile-time
1546** option) the application must supply a suitable implementation for
1547** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
1548** implementation of sqlite3_os_init() or sqlite3_os_end()
1549** must return [SQLITE_OK] on success and some other [error code] upon
1550** failure.
1552SQLITE_API int SQLITE_STDCALL sqlite3_initialize(void);
1553SQLITE_API int SQLITE_STDCALL sqlite3_shutdown(void);
1554SQLITE_API int SQLITE_STDCALL sqlite3_os_init(void);
1555SQLITE_API int SQLITE_STDCALL sqlite3_os_end(void);
1558** CAPI3REF: Configuring The SQLite Library
1560** The sqlite3_config() interface is used to make global configuration
1561** changes to SQLite in order to tune SQLite to the specific needs of
1562** the application.  The default configuration is recommended for most
1563** applications and so this routine is usually not necessary.  It is
1564** provided to support rare applications with unusual needs.
1566** The sqlite3_config() interface is not threadsafe.  The application
1567** must insure that no other SQLite interfaces are invoked by other
1568** threads while sqlite3_config() is running.  Furthermore, sqlite3_config()
1569** may only be invoked prior to library initialization using
1570** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1571** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1572** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1573** Note, however, that ^sqlite3_config() can be called as part of the
1574** implementation of an application-defined [sqlite3_os_init()].
1576** The first argument to sqlite3_config() is an integer
1577** [configuration option] that determines
1578** what property of SQLite is to be configured.  Subsequent arguments
1579** vary depending on the [configuration option]
1580** in the first argument.
1582** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1583** ^If the option is unknown or SQLite is unable to set the option
1584** then this routine returns a non-zero [error code].
1586SQLITE_API int SQLITE_CDECL sqlite3_config(int, ...);
1589** CAPI3REF: Configure database connections
1590** METHOD: sqlite3
1592** The sqlite3_db_config() interface is used to make configuration
1593** changes to a [database connection].  The interface is similar to
1594** [sqlite3_config()] except that the changes apply to a single
1595** [database connection] (specified in the first argument).
1597** The second argument to sqlite3_db_config(D,V,...)  is the
1598** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1599** that indicates what aspect of the [database connection] is being configured.
1600** Subsequent arguments vary depending on the configuration verb.
1602** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1603** the call is considered successful.
1605SQLITE_API int SQLITE_CDECL sqlite3_db_config(sqlite3*, int op, ...);
1608** CAPI3REF: Memory Allocation Routines
1610** An instance of this object defines the interface between SQLite
1611** and low-level memory allocation routines.
1613** This object is used in only one place in the SQLite interface.
1614** A pointer to an instance of this object is the argument to
1615** [sqlite3_config()] when the configuration option is
1617** By creating an instance of this object
1618** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1619** during configuration, an application can specify an alternative
1620** memory allocation subsystem for SQLite to use for all of its
1621** dynamic memory needs.
1623** Note that SQLite comes with several [built-in memory allocators]
1624** that are perfectly adequate for the overwhelming majority of applications
1625** and that this object is only useful to a tiny minority of applications
1626** with specialized memory allocation requirements.  This object is
1627** also used during testing of SQLite in order to specify an alternative
1628** memory allocator that simulates memory out-of-memory conditions in
1629** order to verify that SQLite recovers gracefully from such
1630** conditions.
1632** The xMalloc, xRealloc, and xFree methods must work like the
1633** malloc(), realloc() and free() functions from the standard C library.
1634** ^SQLite guarantees that the second argument to
1635** xRealloc is always a value returned by a prior call to xRoundup.
1637** xSize should return the allocated size of a memory allocation
1638** previously obtained from xMalloc or xRealloc.  The allocated size
1639** is always at least as big as the requested size but may be larger.
1641** The xRoundup method returns what would be the allocated size of
1642** a memory allocation given a particular requested size.  Most memory
1643** allocators round up memory allocations at least to the next multiple
1644** of 8.  Some allocators round up to a larger multiple or to a power of 2.
1645** Every memory allocation request coming in through [sqlite3_malloc()]
1646** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
1647** that causes the corresponding memory allocation to fail.
1649** The xInit method initializes the memory allocator.  For example,
1650** it might allocate any require mutexes or initialize internal data
1651** structures.  The xShutdown method is invoked (indirectly) by
1652** [sqlite3_shutdown()] and should deallocate any resources acquired
1653** by xInit.  The pAppData pointer is used as the only parameter to
1654** xInit and xShutdown.
1656** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1657** the xInit method, so the xInit method need not be threadsafe.  The
1658** xShutdown method is only called from [sqlite3_shutdown()] so it does
1659** not need to be threadsafe either.  For all other methods, SQLite
1660** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1661** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1662** it is by default) and so the methods are automatically serialized.
1663** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1664** methods must be threadsafe or else make their own arrangements for
1665** serialization.
1667** SQLite will never invoke xInit() more than once without an intervening
1668** call to xShutdown().
1670typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1671struct sqlite3_mem_methods {
1672  void *(*xMalloc)(int);         /* Memory allocation function */
1673  void (*xFree)(void*);          /* Free a prior allocation */
1674  void *(*xRealloc)(void*,int);  /* Resize an allocation */
1675  int (*xSize)(void*);           /* Return the size of an allocation */
1676  int (*xRoundup)(int);          /* Round up request size to allocation size */
1677  int (*xInit)(void*);           /* Initialize the memory allocator */
1678  void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
1679  void *pAppData;                /* Argument to xInit() and xShutdown() */
1683** CAPI3REF: Configuration Options
1684** KEYWORDS: {configuration option}
1686** These constants are the available integer configuration options that
1687** can be passed as the first argument to the [sqlite3_config()] interface.
1689** New configuration options may be added in future releases of SQLite.
1690** Existing configuration options might be discontinued.  Applications
1691** should check the return code from [sqlite3_config()] to make sure that
1692** the call worked.  The [sqlite3_config()] interface will return a
1693** non-zero [error code] if a discontinued or unsupported configuration option
1694** is invoked.
1696** <dl>
1698** <dd>There are no arguments to this option.  ^This option sets the
1699** [threading mode] to Single-thread.  In other words, it disables
1700** all mutexing and puts SQLite into a mode where it can only be used
1701** by a single thread.   ^If SQLite is compiled with
1702** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1703** it is not possible to change the [threading mode] from its default
1704** value of Single-thread and so [sqlite3_config()] will return
1706** configuration option.</dd>
1709** <dd>There are no arguments to this option.  ^This option sets the
1710** [threading mode] to Multi-thread.  In other words, it disables
1711** mutexing on [database connection] and [prepared statement] objects.
1712** The application is responsible for serializing access to
1713** [database connections] and [prepared statements].  But other mutexes
1714** are enabled so that SQLite will be safe to use in a multi-threaded
1715** environment as long as no two threads attempt to use the same
1716** [database connection] at the same time.  ^If SQLite is compiled with
1717** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1718** it is not possible to set the Multi-thread [threading mode] and
1719** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1720** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1723** <dd>There are no arguments to this option.  ^This option sets the
1724** [threading mode] to Serialized. In other words, this option enables
1725** all mutexes including the recursive
1726** mutexes on [database connection] and [prepared statement] objects.
1727** In this mode (which is the default when SQLite is compiled with
1728** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1729** to [database connections] and [prepared statements] so that the
1730** application is free to use the same [database connection] or the
1731** same [prepared statement] in different threads at the same time.
1732** ^If SQLite is compiled with
1733** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1734** it is not possible to set the Serialized [threading mode] and
1735** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1736** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1739** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1740** a pointer to an instance of the [sqlite3_mem_methods] structure.
1741** The argument specifies
1742** alternative low-level memory allocation routines to be used in place of
1743** the memory allocation routines built into SQLite.)^ ^SQLite makes
1744** its own private copy of the content of the [sqlite3_mem_methods] structure
1745** before the [sqlite3_config()] call returns.</dd>
1748** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1749** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1750** The [sqlite3_mem_methods]
1751** structure is filled with the currently defined memory allocation routines.)^
1752** This option can be used to overload the default memory allocation
1753** routines with a wrapper that simulations memory allocation failure or
1754** tracks memory usage, for example. </dd>
1757** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1758** interpreted as a boolean, which enables or disables the collection of
1759** memory allocation statistics. ^(When memory allocation statistics are
1760** disabled, the following SQLite interfaces become non-operational:
1761**   <ul>
1762**   <li> [sqlite3_memory_used()]
1763**   <li> [sqlite3_memory_highwater()]
1764**   <li> [sqlite3_soft_heap_limit64()]
1765**   <li> [sqlite3_status64()]
1766**   </ul>)^
1767** ^Memory allocation statistics are enabled by default unless SQLite is
1768** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1769** allocation statistics are disabled by default.
1770** </dd>
1773** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer
1774** that SQLite can use for scratch memory.  ^(There are three arguments
1775** to SQLITE_CONFIG_SCRATCH:  A pointer an 8-byte
1776** aligned memory buffer from which the scratch allocations will be
1777** drawn, the size of each scratch allocation (sz),
1778** and the maximum number of scratch allocations (N).)^
1779** The first argument must be a pointer to an 8-byte aligned buffer
1780** of at least sz*N bytes of memory.
1781** ^SQLite will not use more than one scratch buffers per thread.
1782** ^SQLite will never request a scratch buffer that is more than 6
1783** times the database page size.
1784** ^If SQLite needs needs additional
1785** scratch memory beyond what is provided by this configuration option, then
1786** [sqlite3_malloc()] will be used to obtain the memory needed.<p>
1787** ^When the application provides any amount of scratch memory using
1788** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large
1789** [sqlite3_malloc|heap allocations].
1790** This can help [Robson proof|prevent memory allocation failures] due to heap
1791** fragmentation in low-memory embedded systems.
1792** </dd>
1795** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a static memory buffer
1796** that SQLite can use for the database page cache with the default page
1797** cache implementation.
1798** This configuration should not be used if an application-define page
1799** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]
1800** configuration option.
1801** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1802** 8-byte aligned
1803** memory, the size of each page buffer (sz), and the number of pages (N).
1804** The sz argument should be the size of the largest database page
1805** (a power of two between 512 and 65536) plus some extra bytes for each
1806** page header.  ^The number of extra bytes needed by the page header
1807** can be determined using the [SQLITE_CONFIG_PCACHE_HDRSZ] option
1808** to [sqlite3_config()].
1809** ^It is harmless, apart from the wasted memory,
1810** for the sz parameter to be larger than necessary.  The first
1811** argument should pointer to an 8-byte aligned block of memory that
1812** is at least sz*N bytes of memory, otherwise subsequent behavior is
1813** undefined.
1814** ^SQLite will use the memory provided by the first argument to satisfy its
1815** memory needs for the first N pages that it adds to cache.  ^If additional
1816** page cache memory is needed beyond what is provided by this option, then
1817** SQLite goes to [sqlite3_malloc()] for the additional storage space.</dd>
1820** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1821** that SQLite will use for all of its dynamic memory allocation needs
1822** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and
1824** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1825** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1826** [SQLITE_ERROR] if invoked otherwise.
1827** ^There are three arguments to SQLITE_CONFIG_HEAP:
1828** An 8-byte aligned pointer to the memory,
1829** the number of bytes in the memory buffer, and the minimum allocation size.
1830** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1831** to using its default memory allocator (the system malloc() implementation),
1832** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
1833** memory pointer is not NULL then the alternative memory
1834** allocator is engaged to handle all of SQLites memory allocation needs.
1835** The first pointer (the memory pointer) must be aligned to an 8-byte
1836** boundary or subsequent behavior of SQLite will be undefined.
1837** The minimum allocation size is capped at 2**12. Reasonable values
1838** for the minimum allocation size are 2**5 through 2**8.</dd>
1841** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1842** pointer to an instance of the [sqlite3_mutex_methods] structure.
1843** The argument specifies alternative low-level mutex routines to be used
1844** in place the mutex routines built into SQLite.)^  ^SQLite makes a copy of
1845** the content of the [sqlite3_mutex_methods] structure before the call to
1846** [sqlite3_config()] returns. ^If SQLite is compiled with
1847** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1848** the entire mutexing subsystem is omitted from the build and hence calls to
1849** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1850** return [SQLITE_ERROR].</dd>
1853** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1854** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
1855** [sqlite3_mutex_methods]
1856** structure is filled with the currently defined mutex routines.)^
1857** This option can be used to overload the default mutex allocation
1858** routines with a wrapper used to track mutex usage for performance
1859** profiling or testing, for example.   ^If SQLite is compiled with
1860** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1861** the entire mutexing subsystem is omitted from the build and hence calls to
1862** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1863** return [SQLITE_ERROR].</dd>
1866** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1867** the default size of lookaside memory on each [database connection].
1868** The first argument is the
1869** size of each lookaside buffer slot and the second is the number of
1870** slots allocated to each database connection.)^  ^(SQLITE_CONFIG_LOOKASIDE
1871** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1872** option to [sqlite3_db_config()] can be used to change the lookaside
1873** configuration on individual connections.)^ </dd>
1876** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1877** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
1878** the interface to a custom page cache implementation.)^
1879** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1882** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1883** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies of
1884** the current page cache implementation into that object.)^ </dd>
1887** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1888** global [error log].
1889** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1890** function with a call signature of void(*)(void*,int,const char*),
1891** and a pointer to void. ^If the function pointer is not NULL, it is
1892** invoked by [sqlite3_log()] to process each logging event.  ^If the
1893** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1894** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1895** passed through as the first parameter to the application-defined logger
1896** function whenever that function is invoked.  ^The second parameter to
1897** the logger function is a copy of the first parameter to the corresponding
1898** [sqlite3_log()] call and is intended to be a [result code] or an
1899** [extended result code].  ^The third parameter passed to the logger is
1900** log message after formatting via [sqlite3_snprintf()].
1901** The SQLite logging interface is not reentrant; the logger function
1902** supplied by the application must not invoke any SQLite interface.
1903** In a multi-threaded application, the application-defined logger
1904** function must be threadsafe. </dd>
1907** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1908** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1909** then URI handling is globally disabled.)^ ^If URI handling is globally
1910** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1911** [sqlite3_open16()] or
1912** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1913** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1914** connection is opened. ^If it is globally disabled, filenames are
1915** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1916** database connection is opened. ^(By default, URI handling is globally
1917** disabled. The default value may be changed by compiling with the
1918** [SQLITE_USE_URI] symbol defined.)^
1921** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1922** argument which is interpreted as a boolean in order to enable or disable
1923** the use of covering indices for full table scans in the query optimizer.
1924** ^The default setting is determined
1925** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1926** if that compile-time option is omitted.
1927** The ability to disable the use of covering indices for full table scans
1928** is because some incorrectly coded legacy applications might malfunction
1929** when the optimization is enabled.  Providing the ability to
1930** disable the optimization allows the older, buggy application code to work
1931** without change even with newer versions of SQLite.
1935** <dd> These options are obsolete and should not be used by new code.
1936** They are retained for backwards compatibility but are now no-ops.
1937** </dd>
1941** <dd>This option is only available if sqlite is compiled with the
1942** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1943** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1944** The second should be of type (void*). The callback is invoked by the library
1945** in three separate circumstances, identified by the value passed as the
1946** fourth parameter. If the fourth parameter is 0, then the database connection
1947** passed as the second argument has just been opened. The third argument
1948** points to a buffer containing the name of the main database file. If the
1949** fourth parameter is 1, then the SQL statement that the third parameter
1950** points to has just been executed. Or, if the fourth parameter is 2, then
1951** the connection being passed as the second parameter is being closed. The
1952** third parameter is passed NULL In this case.  An example of using this
1953** configuration option can be seen in the "test_sqllog.c" source file in
1954** the canonical SQLite source tree.</dd>
1958** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1959** that are the default mmap size limit (the default setting for
1960** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1961** ^The default setting can be overridden by each database connection using
1962** either the [PRAGMA mmap_size] command, or by using the
1963** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
1964** will be silently truncated if necessary so that it does not exceed the
1965** compile-time maximum mmap size set by the
1966** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1967** ^If either argument to this option is negative, then that argument is
1968** changed to its compile-time default.
1972** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
1973** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
1974** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1975** that specifies the maximum size of the created heap.
1979** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
1980** is a pointer to an integer and writes into that integer the number of extra
1981** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
1982** The amount of extra space required can change depending on the compiler,
1983** target platform, and SQLite version.
1987** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
1988** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
1989** sorter to that integer.  The default minimum PMA Size is set by the
1990** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
1991** to help with sort operations when multithreaded sorting
1992** is enabled (using the [PRAGMA threads] command) and the amount of content
1993** to be sorted exceeds the page size times the minimum of the
1994** [PRAGMA cache_size] setting and this value.
1995** </dl>
1997#define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
1998#define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
1999#define SQLITE_CONFIG_SERIALIZED    3  /* nil */
2000#define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
2001#define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
2002#define SQLITE_CONFIG_SCRATCH       6  /* void*, int sz, int N */
2003#define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
2004#define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
2005#define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
2006#define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
2007#define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
2008/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
2009#define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
2010#define SQLITE_CONFIG_PCACHE       14  /* no-op */
2011#define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
2012#define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
2013#define SQLITE_CONFIG_URI          17  /* int */
2014#define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
2015#define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
2016#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
2017#define SQLITE_CONFIG_SQLLOG       21  /* xSqllog, void* */
2018#define SQLITE_CONFIG_MMAP_SIZE    22  /* sqlite3_int64, sqlite3_int64 */
2019#define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
2020#define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
2021#define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
2024** CAPI3REF: Database Connection Configuration Options
2026** These constants are the available integer configuration options that
2027** can be passed as the second argument to the [sqlite3_db_config()] interface.
2029** New configuration options may be added in future releases of SQLite.
2030** Existing configuration options might be discontinued.  Applications
2031** should check the return code from [sqlite3_db_config()] to make sure that
2032** the call worked.  ^The [sqlite3_db_config()] interface will return a
2033** non-zero [error code] if a discontinued or unsupported configuration option
2034** is invoked.
2036** <dl>
2038** <dd> ^This option takes three additional arguments that determine the
2039** [lookaside memory allocator] configuration for the [database connection].
2040** ^The first argument (the third parameter to [sqlite3_db_config()] is a
2041** pointer to a memory buffer to use for lookaside memory.
2042** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
2043** may be NULL in which case SQLite will allocate the
2044** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
2045** size of each lookaside buffer slot.  ^The third argument is the number of
2046** slots.  The size of the buffer in the first argument must be greater than
2047** or equal to the product of the second and third arguments.  The buffer
2048** must be aligned to an 8-byte boundary.  ^If the second argument to
2049** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
2050** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
2051** configuration for a database connection can only be changed when that
2052** connection is not currently using lookaside memory, or in other words
2053** when the "current value" returned by
2054** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
2055** Any attempt to change the lookaside memory configuration when lookaside
2056** memory is in use leaves the configuration unchanged and returns
2057** [SQLITE_BUSY].)^</dd>
2060** <dd> ^This option is used to enable or disable the enforcement of
2061** [foreign key constraints].  There should be two additional arguments.
2062** The first argument is an integer which is 0 to disable FK enforcement,
2063** positive to enable FK enforcement or negative to leave FK enforcement
2064** unchanged.  The second parameter is a pointer to an integer into which
2065** is written 0 or 1 to indicate whether FK enforcement is off or on
2066** following this call.  The second parameter may be a NULL pointer, in
2067** which case the FK enforcement setting is not reported back. </dd>
2070** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
2071** There should be two additional arguments.
2072** The first argument is an integer which is 0 to disable triggers,
2073** positive to enable triggers or negative to leave the setting unchanged.
2074** The second parameter is a pointer to an integer into which
2075** is written 0 or 1 to indicate whether triggers are disabled or enabled
2076** following this call.  The second parameter may be a NULL pointer, in
2077** which case the trigger setting is not reported back. </dd>
2079** </dl>
2081#define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */
2082#define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */
2083#define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */
2087** CAPI3REF: Enable Or Disable Extended Result Codes
2088** METHOD: sqlite3
2090** ^The sqlite3_extended_result_codes() routine enables or disables the
2091** [extended result codes] feature of SQLite. ^The extended result
2092** codes are disabled by default for historical compatibility.
2094SQLITE_API int SQLITE_STDCALL sqlite3_extended_result_codes(sqlite3*, int onoff);
2097** CAPI3REF: Last Insert Rowid
2098** METHOD: sqlite3
2100** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
2101** has a unique 64-bit signed
2102** integer key called the [ROWID | "rowid"]. ^The rowid is always available
2103** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
2104** names are not also used by explicitly declared columns. ^If
2105** the table has a column of type [INTEGER PRIMARY KEY] then that column
2106** is another alias for the rowid.
2108** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the
2109** most recent successful [INSERT] into a rowid table or [virtual table]
2110** on database connection D.
2111** ^Inserts into [WITHOUT ROWID] tables are not recorded.
2112** ^If no successful [INSERT]s into rowid tables
2113** have ever occurred on the database connection D,
2114** then sqlite3_last_insert_rowid(D) returns zero.
2116** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
2117** method, then this routine will return the [rowid] of the inserted
2118** row as long as the trigger or virtual table method is running.
2119** But once the trigger or virtual table method ends, the value returned
2120** by this routine reverts to what it was before the trigger or virtual
2121** table method began.)^
2123** ^An [INSERT] that fails due to a constraint violation is not a
2124** successful [INSERT] and does not change the value returned by this
2126** and INSERT OR ABORT make no changes to the return value of this
2127** routine when their insertion fails.  ^(When INSERT OR REPLACE
2128** encounters a constraint violation, it does not fail.  The
2129** INSERT continues to completion after deleting rows that caused
2130** the constraint problem so INSERT OR REPLACE will always change
2131** the return value of this interface.)^
2133** ^For the purposes of this routine, an [INSERT] is considered to
2134** be successful even if it is subsequently rolled back.
2136** This function is accessible to SQL statements via the
2137** [last_insert_rowid() SQL function].
2139** If a separate thread performs a new [INSERT] on the same
2140** database connection while the [sqlite3_last_insert_rowid()]
2141** function is running and thus changes the last insert [rowid],
2142** then the value returned by [sqlite3_last_insert_rowid()] is
2143** unpredictable and might not equal either the old or the new
2144** last insert [rowid].
2146SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_last_insert_rowid(sqlite3*);
2149** CAPI3REF: Count The Number Of Rows Modified
2150** METHOD: sqlite3
2152** ^This function returns the number of rows modified, inserted or
2153** deleted by the most recently completed INSERT, UPDATE or DELETE
2154** statement on the database connection specified by the only parameter.
2155** ^Executing any other type of SQL statement does not modify the value
2156** returned by this function.
2158** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
2159** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
2160** [foreign key actions] or [REPLACE] constraint resolution are not counted.
2162** Changes to a view that are intercepted by
2163** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
2164** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
2165** DELETE statement run on a view is always zero. Only changes made to real
2166** tables are counted.
2168** Things are more complicated if the sqlite3_changes() function is
2169** executed while a trigger program is running. This may happen if the
2170** program uses the [changes() SQL function], or if some other callback
2171** function invokes sqlite3_changes() directly. Essentially:
2173** <ul>
2174**   <li> ^(Before entering a trigger program the value returned by
2175**        sqlite3_changes() function is saved. After the trigger program
2176**        has finished, the original value is restored.)^
2178**   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
2179**        statement sets the value returned by sqlite3_changes()
2180**        upon completion as normal. Of course, this value will not include
2181**        any changes performed by sub-triggers, as the sqlite3_changes()
2182**        value will be saved and restored after each sub-trigger has run.)^
2183** </ul>
2185** ^This means that if the changes() SQL function (or similar) is used
2186** by the first INSERT, UPDATE or DELETE statement within a trigger, it
2187** returns the value as set when the calling statement began executing.
2188** ^If it is used by the second or subsequent such statement within a trigger
2189** program, the value returned reflects the number of rows modified by the
2190** previous INSERT, UPDATE or DELETE statement within the same trigger.
2192** See also the [sqlite3_total_changes()] interface, the
2193** [count_changes pragma], and the [changes() SQL function].
2195** If a separate thread makes changes on the same database connection
2196** while [sqlite3_changes()] is running then the value returned
2197** is unpredictable and not meaningful.
2199SQLITE_API int SQLITE_STDCALL sqlite3_changes(sqlite3*);
2202** CAPI3REF: Total Number Of Rows Modified
2203** METHOD: sqlite3
2205** ^This function returns the total number of rows inserted, modified or
2206** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2207** since the database connection was opened, including those executed as
2208** part of trigger programs. ^Executing any other type of SQL statement
2209** does not affect the value returned by sqlite3_total_changes().
2211** ^Changes made as part of [foreign key actions] are included in the
2212** count, but those made as part of REPLACE constraint resolution are
2213** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2214** are not counted.
2216** See also the [sqlite3_changes()] interface, the
2217** [count_changes pragma], and the [total_changes() SQL function].
2219** If a separate thread makes changes on the same database connection
2220** while [sqlite3_total_changes()] is running then the value
2221** returned is unpredictable and not meaningful.
2223SQLITE_API int SQLITE_STDCALL sqlite3_total_changes(sqlite3*);
2226** CAPI3REF: Interrupt A Long-Running Query
2227** METHOD: sqlite3
2229** ^This function causes any pending database operation to abort and
2230** return at its earliest opportunity. This routine is typically
2231** called in response to a user action such as pressing "Cancel"
2232** or Ctrl-C where the user wants a long query operation to halt
2233** immediately.
2235** ^It is safe to call this routine from a thread different from the
2236** thread that is currently running the database operation.  But it
2237** is not safe to call this routine with a [database connection] that
2238** is closed or might close before sqlite3_interrupt() returns.
2240** ^If an SQL operation is very nearly finished at the time when
2241** sqlite3_interrupt() is called, then it might not have an opportunity
2242** to be interrupted and might continue to completion.
2244** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2245** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2246** that is inside an explicit transaction, then the entire transaction
2247** will be rolled back automatically.
2249** ^The sqlite3_interrupt(D) call is in effect until all currently running
2250** SQL statements on [database connection] D complete.  ^Any new SQL statements
2251** that are started after the sqlite3_interrupt() call and before the
2252** running statements reaches zero are interrupted as if they had been
2253** running prior to the sqlite3_interrupt() call.  ^New SQL statements
2254** that are started after the running statement count reaches zero are
2255** not effected by the sqlite3_interrupt().
2256** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2257** SQL statements is a no-op and has no effect on SQL statements
2258** that are started after the sqlite3_interrupt() call returns.
2260** If the database connection closes while [sqlite3_interrupt()]
2261** is running then bad things will likely happen.
2263SQLITE_API void SQLITE_STDCALL sqlite3_interrupt(sqlite3*);
2266** CAPI3REF: Determine If An SQL Statement Is Complete
2268** These routines are useful during command-line input to determine if the
2269** currently entered text seems to form a complete SQL statement or
2270** if additional input is needed before sending the text into
2271** SQLite for parsing.  ^These routines return 1 if the input string
2272** appears to be a complete SQL statement.  ^A statement is judged to be
2273** complete if it ends with a semicolon token and is not a prefix of a
2274** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
2275** string literals or quoted identifier names or comments are not
2276** independent tokens (they are part of the token in which they are
2277** embedded) and thus do not count as a statement terminator.  ^Whitespace
2278** and comments that follow the final semicolon are ignored.
2280** ^These routines return 0 if the statement is incomplete.  ^If a
2281** memory allocation fails, then SQLITE_NOMEM is returned.
2283** ^These routines do not parse the SQL statements thus
2284** will not detect syntactically incorrect SQL.
2286** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2287** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2288** automatically by sqlite3_complete16().  If that initialization fails,
2289** then the return value from sqlite3_complete16() will be non-zero
2290** regardless of whether or not the input SQL is complete.)^
2292** The input to [sqlite3_complete()] must be a zero-terminated
2293** UTF-8 string.
2295** The input to [sqlite3_complete16()] must be a zero-terminated
2296** UTF-16 string in native byte order.
2298SQLITE_API int SQLITE_STDCALL sqlite3_complete(const char *sql);
2299SQLITE_API int SQLITE_STDCALL sqlite3_complete16(const void *sql);
2302** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2303** KEYWORDS: {busy-handler callback} {busy handler}
2304** METHOD: sqlite3
2306** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2307** that might be invoked with argument P whenever
2308** an attempt is made to access a database table associated with
2309** [database connection] D when another thread
2310** or process has the table locked.
2311** The sqlite3_busy_handler() interface is used to implement
2312** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2314** ^If the busy callback is NULL, then [SQLITE_BUSY]
2315** is returned immediately upon encountering the lock.  ^If the busy callback
2316** is not NULL, then the callback might be invoked with two arguments.
2318** ^The first argument to the busy handler is a copy of the void* pointer which
2319** is the third argument to sqlite3_busy_handler().  ^The second argument to
2320** the busy handler callback is the number of times that the busy handler has
2321** been invoked previously for the same locking event.  ^If the
2322** busy callback returns 0, then no additional attempts are made to
2323** access the database and [SQLITE_BUSY] is returned
2324** to the application.
2325** ^If the callback returns non-zero, then another attempt
2326** is made to access the database and the cycle repeats.
2328** The presence of a busy handler does not guarantee that it will be invoked
2329** when there is lock contention. ^If SQLite determines that invoking the busy
2330** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2331** to the application instead of invoking the
2332** busy handler.
2333** Consider a scenario where one process is holding a read lock that
2334** it is trying to promote to a reserved lock and
2335** a second process is holding a reserved lock that it is trying
2336** to promote to an exclusive lock.  The first process cannot proceed
2337** because it is blocked by the second and the second process cannot
2338** proceed because it is blocked by the first.  If both processes
2339** invoke the busy handlers, neither will make any progress.  Therefore,
2340** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2341** will induce the first process to release its read lock and allow
2342** the second process to proceed.
2344** ^The default busy callback is NULL.
2346** ^(There can only be a single busy handler defined for each
2347** [database connection].  Setting a new busy handler clears any
2348** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
2349** or evaluating [PRAGMA busy_timeout=N] will change the
2350** busy handler and thus clear any previously set busy handler.
2352** The busy callback should not take any actions which modify the
2353** database connection that invoked the busy handler.  In other words,
2354** the busy handler is not reentrant.  Any such actions
2355** result in undefined behavior.
2357** A busy handler must not close the database connection
2358** or [prepared statement] that invoked the busy handler.
2360SQLITE_API int SQLITE_STDCALL sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
2363** CAPI3REF: Set A Busy Timeout
2364** METHOD: sqlite3
2366** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2367** for a specified amount of time when a table is locked.  ^The handler
2368** will sleep multiple times until at least "ms" milliseconds of sleeping
2369** have accumulated.  ^After at least "ms" milliseconds of sleeping,
2370** the handler returns 0 which causes [sqlite3_step()] to return
2371** [SQLITE_BUSY].
2373** ^Calling this routine with an argument less than or equal to zero
2374** turns off all busy handlers.
2376** ^(There can only be a single busy handler for a particular
2377** [database connection] at any given moment.  If another busy handler
2378** was defined  (using [sqlite3_busy_handler()]) prior to calling
2379** this routine, that other busy handler is cleared.)^
2381** See also:  [PRAGMA busy_timeout]
2383SQLITE_API int SQLITE_STDCALL sqlite3_busy_timeout(sqlite3*, int ms);
2386** CAPI3REF: Convenience Routines For Running Queries
2387** METHOD: sqlite3
2389** This is a legacy interface that is preserved for backwards compatibility.
2390** Use of this interface is not recommended.
2392** Definition: A <b>result table</b> is memory data structure created by the
2393** [sqlite3_get_table()] interface.  A result table records the
2394** complete query results from one or more queries.
2396** The table conceptually has a number of rows and columns.  But
2397** these numbers are not part of the result table itself.  These
2398** numbers are obtained separately.  Let N be the number of rows
2399** and M be the number of columns.
2401** A result table is an array of pointers to zero-terminated UTF-8 strings.
2402** There are (N+1)*M elements in the array.  The first M pointers point
2403** to zero-terminated strings that  contain the names of the columns.
2404** The remaining entries all point to query results.  NULL values result
2405** in NULL pointers.  All other values are in their UTF-8 zero-terminated
2406** string representation as returned by [sqlite3_column_text()].
2408** A result table might consist of one or more memory allocations.
2409** It is not safe to pass a result table directly to [sqlite3_free()].
2410** A result table should be deallocated using [sqlite3_free_table()].
2412** ^(As an example of the result table format, suppose a query result
2413** is as follows:
2415** <blockquote><pre>
2416**        Name        | Age
2417**        -----------------------
2418**        Alice       | 43
2419**        Bob         | 28
2420**        Cindy       | 21
2421** </pre></blockquote>
2423** There are two column (M==2) and three rows (N==3).  Thus the
2424** result table has 8 entries.  Suppose the result table is stored
2425** in an array names azResult.  Then azResult holds this content:
2427** <blockquote><pre>
2428**        azResult&#91;0] = "Name";
2429**        azResult&#91;1] = "Age";
2430**        azResult&#91;2] = "Alice";
2431**        azResult&#91;3] = "43";
2432**        azResult&#91;4] = "Bob";
2433**        azResult&#91;5] = "28";
2434**        azResult&#91;6] = "Cindy";
2435**        azResult&#91;7] = "21";
2436** </pre></blockquote>)^
2438** ^The sqlite3_get_table() function evaluates one or more
2439** semicolon-separated SQL statements in the zero-terminated UTF-8
2440** string of its 2nd parameter and returns a result table to the
2441** pointer given in its 3rd parameter.
2443** After the application has finished with the result from sqlite3_get_table(),
2444** it must pass the result table pointer to sqlite3_free_table() in order to
2445** release the memory that was malloced.  Because of the way the
2446** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2447** function must not try to call [sqlite3_free()] directly.  Only
2448** [sqlite3_free_table()] is able to release the memory properly and safely.
2450** The sqlite3_get_table() interface is implemented as a wrapper around
2451** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
2452** to any internal data structures of SQLite.  It uses only the public
2453** interface defined here.  As a consequence, errors that occur in the
2454** wrapper layer outside of the internal [sqlite3_exec()] call are not
2455** reflected in subsequent calls to [sqlite3_errcode()] or
2456** [sqlite3_errmsg()].
2458SQLITE_API int SQLITE_STDCALL sqlite3_get_table(
2459  sqlite3 *db,          /* An open database */
2460  const char *zSql,     /* SQL to be evaluated */
2461  char ***pazResult,    /* Results of the query */
2462  int *pnRow,           /* Number of result rows written here */
2463  int *pnColumn,        /* Number of result columns written here */
2464  char **pzErrmsg       /* Error msg written here */
2466SQLITE_API void SQLITE_STDCALL sqlite3_free_table(char **result);
2469** CAPI3REF: Formatted String Printing Functions
2471** These routines are work-alikes of the "printf()" family of functions
2472** from the standard C library.
2473** These routines understand most of the common K&R formatting options,
2474** plus some additional non-standard formats, detailed below.
2475** Note that some of the more obscure formatting options from recent
2476** C-library standards are omitted from this implementation.
2478** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2479** results into memory obtained from [sqlite3_malloc()].
2480** The strings returned by these two routines should be
2481** released by [sqlite3_free()].  ^Both routines return a
2482** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2483** memory to hold the resulting string.
2485** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2486** the standard C library.  The result is written into the
2487** buffer supplied as the second parameter whose size is given by
2488** the first parameter. Note that the order of the
2489** first two parameters is reversed from snprintf().)^  This is an
2490** historical accident that cannot be fixed without breaking
2491** backwards compatibility.  ^(Note also that sqlite3_snprintf()
2492** returns a pointer to its buffer instead of the number of
2493** characters actually written into the buffer.)^  We admit that
2494** the number of characters written would be a more useful return
2495** value but we cannot change the implementation of sqlite3_snprintf()
2496** now without breaking compatibility.
2498** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2499** guarantees that the buffer is always zero-terminated.  ^The first
2500** parameter "n" is the total size of the buffer, including space for
2501** the zero terminator.  So the longest string that can be completely
2502** written will be n-1 characters.
2504** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2506** These routines all implement some additional formatting
2507** options that are useful for constructing SQL statements.
2508** All of the usual printf() formatting options apply.  In addition, there
2509** is are "%q", "%Q", "%w" and "%z" options.
2511** ^(The %q option works like %s in that it substitutes a nul-terminated
2512** string from the argument list.  But %q also doubles every '\'' character.
2513** %q is designed for use inside a string literal.)^  By doubling each '\''
2514** character it escapes that character and allows it to be inserted into
2515** the string.
2517** For example, assume the string variable zText contains text as follows:
2519** <blockquote><pre>
2520**  char *zText = "It's a happy day!";
2521** </pre></blockquote>
2523** One can use this text in an SQL statement as follows:
2525** <blockquote><pre>
2526**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2527**  sqlite3_exec(db, zSQL, 0, 0, 0);
2528**  sqlite3_free(zSQL);
2529** </pre></blockquote>
2531** Because the %q format string is used, the '\'' character in zText
2532** is escaped and the SQL generated is as follows:
2534** <blockquote><pre>
2535**  INSERT INTO table1 VALUES('It''s a happy day!')
2536** </pre></blockquote>
2538** This is correct.  Had we used %s instead of %q, the generated SQL
2539** would have looked like this:
2541** <blockquote><pre>
2542**  INSERT INTO table1 VALUES('It's a happy day!');
2543** </pre></blockquote>
2545** This second example is an SQL syntax error.  As a general rule you should
2546** always use %q instead of %s when inserting text into a string literal.
2548** ^(The %Q option works like %q except it also adds single quotes around
2549** the outside of the total string.  Additionally, if the parameter in the
2550** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2551** single quotes).)^  So, for example, one could say:
2553** <blockquote><pre>
2554**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2555**  sqlite3_exec(db, zSQL, 0, 0, 0);
2556**  sqlite3_free(zSQL);
2557** </pre></blockquote>
2559** The code above will render a correct SQL statement in the zSQL
2560** variable even if the zText variable is a NULL pointer.
2562** ^(The "%w" formatting option is like "%q" except that it expects to
2563** be contained within double-quotes instead of single quotes, and it
2564** escapes the double-quote character instead of the single-quote
2565** character.)^  The "%w" formatting option is intended for safely inserting
2566** table and column names into a constructed SQL statement.
2568** ^(The "%z" formatting option works like "%s" but with the
2569** addition that after the string has been read and copied into
2570** the result, [sqlite3_free()] is called on the input string.)^
2572SQLITE_API char *SQLITE_CDECL sqlite3_mprintf(const char*,...);
2573SQLITE_API char *SQLITE_STDCALL sqlite3_vmprintf(const char*, va_list);
2574SQLITE_API char *SQLITE_CDECL sqlite3_snprintf(int,char*,const char*, ...);
2575SQLITE_API char *SQLITE_STDCALL sqlite3_vsnprintf(int,char*,const char*, va_list);
2578** CAPI3REF: Memory Allocation Subsystem
2580** The SQLite core uses these three routines for all of its own
2581** internal memory allocation needs. "Core" in the previous sentence
2582** does not include operating-system specific VFS implementation.  The
2583** Windows VFS uses native malloc() and free() for some operations.
2585** ^The sqlite3_malloc() routine returns a pointer to a block
2586** of memory at least N bytes in length, where N is the parameter.
2587** ^If sqlite3_malloc() is unable to obtain sufficient free
2588** memory, it returns a NULL pointer.  ^If the parameter N to
2589** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2590** a NULL pointer.
2592** ^The sqlite3_malloc64(N) routine works just like
2593** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2594** of a signed 32-bit integer.
2596** ^Calling sqlite3_free() with a pointer previously returned
2597** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2598** that it might be reused.  ^The sqlite3_free() routine is
2599** a no-op if is called with a NULL pointer.  Passing a NULL pointer
2600** to sqlite3_free() is harmless.  After being freed, memory
2601** should neither be read nor written.  Even reading previously freed
2602** memory might result in a segmentation fault or other severe error.
2603** Memory corruption, a segmentation fault, or other severe error
2604** might result if sqlite3_free() is called with a non-NULL pointer that
2605** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2607** ^The sqlite3_realloc(X,N) interface attempts to resize a
2608** prior memory allocation X to be at least N bytes.
2609** ^If the X parameter to sqlite3_realloc(X,N)
2610** is a NULL pointer then its behavior is identical to calling
2611** sqlite3_malloc(N).
2612** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2613** negative then the behavior is exactly the same as calling
2614** sqlite3_free(X).
2615** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2616** of at least N bytes in size or NULL if insufficient memory is available.
2617** ^If M is the size of the prior allocation, then min(N,M) bytes
2618** of the prior allocation are copied into the beginning of buffer returned
2619** by sqlite3_realloc(X,N) and the prior allocation is freed.
2620** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2621** prior allocation is not freed.
2623** ^The sqlite3_realloc64(X,N) interfaces works the same as
2624** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2625** of a 32-bit signed integer.
2627** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2628** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2629** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2630** ^The value returned by sqlite3_msize(X) might be larger than the number
2631** of bytes requested when X was allocated.  ^If X is a NULL pointer then
2632** sqlite3_msize(X) returns zero.  If X points to something that is not
2633** the beginning of memory allocation, or if it points to a formerly
2634** valid memory allocation that has now been freed, then the behavior
2635** of sqlite3_msize(X) is undefined and possibly harmful.
2637** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2638** sqlite3_malloc64(), and sqlite3_realloc64()
2639** is always aligned to at least an 8 byte boundary, or to a
2640** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2641** option is used.
2643** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2644** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2645** implementation of these routines to be omitted.  That capability
2646** is no longer provided.  Only built-in memory allocators can be used.
2648** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2649** the system malloc() and free() directly when converting
2650** filenames between the UTF-8 encoding used by SQLite
2651** and whatever filename encoding is used by the particular Windows
2652** installation.  Memory allocation errors were detected, but
2653** they were reported back as [SQLITE_CANTOPEN] or
2654** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2656** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2657** must be either NULL or else pointers obtained from a prior
2658** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2659** not yet been released.
2661** The application must not read or write any part of
2662** a block of memory after it has been released using
2663** [sqlite3_free()] or [sqlite3_realloc()].
2665SQLITE_API void *SQLITE_STDCALL sqlite3_malloc(int);
2666SQLITE_API void *SQLITE_STDCALL sqlite3_malloc64(sqlite3_uint64);
2667SQLITE_API void *SQLITE_STDCALL sqlite3_realloc(void*, int);
2668SQLITE_API void *SQLITE_STDCALL sqlite3_realloc64(void*, sqlite3_uint64);
2669SQLITE_API void SQLITE_STDCALL sqlite3_free(void*);
2670SQLITE_API sqlite3_uint64 SQLITE_STDCALL sqlite3_msize(void*);
2673** CAPI3REF: Memory Allocator Statistics
2675** SQLite provides these two interfaces for reporting on the status
2676** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2677** routines, which form the built-in memory allocation subsystem.
2679** ^The [sqlite3_memory_used()] routine returns the number of bytes
2680** of memory currently outstanding (malloced but not freed).
2681** ^The [sqlite3_memory_highwater()] routine returns the maximum
2682** value of [sqlite3_memory_used()] since the high-water mark
2683** was last reset.  ^The values returned by [sqlite3_memory_used()] and
2684** [sqlite3_memory_highwater()] include any overhead
2685** added by SQLite in its implementation of [sqlite3_malloc()],
2686** but not overhead added by the any underlying system library
2687** routines that [sqlite3_malloc()] may call.
2689** ^The memory high-water mark is reset to the current value of
2690** [sqlite3_memory_used()] if and only if the parameter to
2691** [sqlite3_memory_highwater()] is true.  ^The value returned
2692** by [sqlite3_memory_highwater(1)] is the high-water mark
2693** prior to the reset.
2695SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_used(void);
2696SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_highwater(int resetFlag);
2699** CAPI3REF: Pseudo-Random Number Generator
2701** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2702** select random [ROWID | ROWIDs] when inserting new records into a table that
2703** already uses the largest possible [ROWID].  The PRNG is also used for
2704** the build-in random() and randomblob() SQL functions.  This interface allows
2705** applications to access the same PRNG for other purposes.
2707** ^A call to this routine stores N bytes of randomness into buffer P.
2708** ^The P parameter can be a NULL pointer.
2710** ^If this routine has not been previously called or if the previous
2711** call had N less than one or a NULL pointer for P, then the PRNG is
2712** seeded using randomness obtained from the xRandomness method of
2713** the default [sqlite3_vfs] object.
2714** ^If the previous call to this routine had an N of 1 or more and a
2715** non-NULL P then the pseudo-randomness is generated
2716** internally and without recourse to the [sqlite3_vfs] xRandomness
2717** method.
2719SQLITE_API void SQLITE_STDCALL sqlite3_randomness(int N, void *P);
2722** CAPI3REF: Compile-Time Authorization Callbacks
2723** METHOD: sqlite3
2725** ^This routine registers an authorizer callback with a particular
2726** [database connection], supplied in the first argument.
2727** ^The authorizer callback is invoked as SQL statements are being compiled
2728** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2729** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  ^At various
2730** points during the compilation process, as logic is being created
2731** to perform various actions, the authorizer callback is invoked to
2732** see if those actions are allowed.  ^The authorizer callback should
2733** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2734** specific action but allow the SQL statement to continue to be
2735** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2736** rejected with an error.  ^If the authorizer callback returns
2737** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2738** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2739** the authorizer will fail with an error message.
2741** When the callback returns [SQLITE_OK], that means the operation
2742** requested is ok.  ^When the callback returns [SQLITE_DENY], the
2743** [sqlite3_prepare_v2()] or equivalent call that triggered the
2744** authorizer will fail with an error message explaining that
2745** access is denied.
2747** ^The first parameter to the authorizer callback is a copy of the third
2748** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2749** to the callback is an integer [SQLITE_COPY | action code] that specifies
2750** the particular action to be authorized. ^The third through sixth parameters
2751** to the callback are zero-terminated strings that contain additional
2752** details about the action to be authorized.
2754** ^If the action code is [SQLITE_READ]
2755** and the callback returns [SQLITE_IGNORE] then the
2756** [prepared statement] statement is constructed to substitute
2757** a NULL value in place of the table column that would have
2758** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
2759** return can be used to deny an untrusted user access to individual
2760** columns of a table.
2761** ^If the action code is [SQLITE_DELETE] and the callback returns
2762** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2763** [truncate optimization] is disabled and all rows are deleted individually.
2765** An authorizer is used when [sqlite3_prepare | preparing]
2766** SQL statements from an untrusted source, to ensure that the SQL statements
2767** do not try to access data they are not allowed to see, or that they do not
2768** try to execute malicious statements that damage the database.  For
2769** example, an application may allow a user to enter arbitrary
2770** SQL queries for evaluation by a database.  But the application does
2771** not want the user to be able to make arbitrary changes to the
2772** database.  An authorizer could then be put in place while the
2773** user-entered SQL is being [sqlite3_prepare | prepared] that
2774** disallows everything except [SELECT] statements.
2776** Applications that need to process SQL from untrusted sources
2777** might also consider lowering resource limits using [sqlite3_limit()]
2778** and limiting database size using the [max_page_count] [PRAGMA]
2779** in addition to using an authorizer.
2781** ^(Only a single authorizer can be in place on a database connection
2782** at a time.  Each call to sqlite3_set_authorizer overrides the
2783** previous call.)^  ^Disable the authorizer by installing a NULL callback.
2784** The authorizer is disabled by default.
2786** The authorizer callback must not do anything that will modify
2787** the database connection that invoked the authorizer callback.
2788** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2789** database connections for the meaning of "modify" in this paragraph.
2791** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2792** statement might be re-prepared during [sqlite3_step()] due to a
2793** schema change.  Hence, the application should ensure that the
2794** correct authorizer callback remains in place during the [sqlite3_step()].
2796** ^Note that the authorizer callback is invoked only during
2797** [sqlite3_prepare()] or its variants.  Authorization is not
2798** performed during statement evaluation in [sqlite3_step()], unless
2799** as stated in the previous paragraph, sqlite3_step() invokes
2800** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2802SQLITE_API int SQLITE_STDCALL sqlite3_set_authorizer(
2803  sqlite3*,
2804  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2805  void *pUserData
2809** CAPI3REF: Authorizer Return Codes
2811** The [sqlite3_set_authorizer | authorizer callback function] must
2812** return either [SQLITE_OK] or one of these two constants in order
2813** to signal SQLite whether or not the action is permitted.  See the
2814** [sqlite3_set_authorizer | authorizer documentation] for additional
2815** information.
2817** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2818** returned from the [sqlite3_vtab_on_conflict()] interface.
2820#define SQLITE_DENY   1   /* Abort the SQL statement with an error */
2821#define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
2824** CAPI3REF: Authorizer Action Codes
2826** The [sqlite3_set_authorizer()] interface registers a callback function
2827** that is invoked to authorize certain SQL statement actions.  The
2828** second parameter to the callback is an integer code that specifies
2829** what action is being authorized.  These are the integer action codes that
2830** the authorizer callback may be passed.
2832** These action code values signify what kind of operation is to be
2833** authorized.  The 3rd and 4th parameters to the authorization
2834** callback function will be parameters or NULL depending on which of these
2835** codes is used as the second parameter.  ^(The 5th parameter to the
2836** authorizer callback is the name of the database ("main", "temp",
2837** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
2838** is the name of the inner-most trigger or view that is responsible for
2839** the access attempt or NULL if this access attempt is directly from
2840** top-level SQL code.
2842/******************************************* 3rd ************ 4th ***********/
2843#define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
2844#define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
2845#define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
2846#define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
2847#define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
2848#define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
2849#define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
2850#define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
2851#define SQLITE_DELETE                9   /* Table Name      NULL            */
2852#define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
2853#define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
2854#define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
2855#define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
2856#define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
2857#define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
2858#define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
2859#define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
2860#define SQLITE_INSERT               18   /* Table Name      NULL            */
2861#define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
2862#define SQLITE_READ                 20   /* Table Name      Column Name     */
2863#define SQLITE_SELECT               21   /* NULL            NULL            */
2864#define SQLITE_TRANSACTION          22   /* Operation       NULL            */
2865#define SQLITE_UPDATE               23   /* Table Name      Column Name     */
2866#define SQLITE_ATTACH               24   /* Filename        NULL            */
2867#define SQLITE_DETACH               25   /* Database Name   NULL            */
2868#define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
2869#define SQLITE_REINDEX              27   /* Index Name      NULL            */
2870#define SQLITE_ANALYZE              28   /* Table Name      NULL            */
2871#define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
2872#define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
2873#define SQLITE_FUNCTION             31   /* NULL            Function Name   */
2874#define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
2875#define SQLITE_COPY                  0   /* No longer used */
2876#define SQLITE_RECURSIVE            33   /* NULL            NULL            */
2879** CAPI3REF: Tracing And Profiling Functions
2880** METHOD: sqlite3
2882** These routines register callback functions that can be used for
2883** tracing and profiling the execution of SQL statements.
2885** ^The callback function registered by sqlite3_trace() is invoked at
2886** various times when an SQL statement is being run by [sqlite3_step()].
2887** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2888** SQL statement text as the statement first begins executing.
2889** ^(Additional sqlite3_trace() callbacks might occur
2890** as each triggered subprogram is entered.  The callbacks for triggers
2891** contain a UTF-8 SQL comment that identifies the trigger.)^
2893** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2894** the length of [bound parameter] expansion in the output of sqlite3_trace().
2896** ^The callback function registered by sqlite3_profile() is invoked
2897** as each SQL statement finishes.  ^The profile callback contains
2898** the original statement text and an estimate of wall-clock time
2899** of how long that statement took to run.  ^The profile callback
2900** time is in units of nanoseconds, however the current implementation
2901** is only capable of millisecond resolution so the six least significant
2902** digits in the time are meaningless.  Future versions of SQLite
2903** might provide greater resolution on the profiler callback.  The
2904** sqlite3_profile() function is considered experimental and is
2905** subject to change in future versions of SQLite.
2907SQLITE_API void *SQLITE_STDCALL sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2908SQLITE_API SQLITE_EXPERIMENTAL void *SQLITE_STDCALL sqlite3_profile(sqlite3*,
2909   void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2912** CAPI3REF: Query Progress Callbacks
2913** METHOD: sqlite3
2915** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2916** function X to be invoked periodically during long running calls to
2917** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2918** database connection D.  An example use for this
2919** interface is to keep a GUI updated during a large query.
2921** ^The parameter P is passed through as the only parameter to the
2922** callback function X.  ^The parameter N is the approximate number of
2923** [virtual machine instructions] that are evaluated between successive
2924** invocations of the callback X.  ^If N is less than one then the progress
2925** handler is disabled.
2927** ^Only a single progress handler may be defined at one time per
2928** [database connection]; setting a new progress handler cancels the
2929** old one.  ^Setting parameter X to NULL disables the progress handler.
2930** ^The progress handler is also disabled by setting N to a value less
2931** than 1.
2933** ^If the progress callback returns non-zero, the operation is
2934** interrupted.  This feature can be used to implement a
2935** "Cancel" button on a GUI progress dialog box.
2937** The progress handler callback must not do anything that will modify
2938** the database connection that invoked the progress handler.
2939** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2940** database connections for the meaning of "modify" in this paragraph.
2943SQLITE_API void SQLITE_STDCALL sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2946** CAPI3REF: Opening A New Database Connection
2947** CONSTRUCTOR: sqlite3
2949** ^These routines open an SQLite database file as specified by the
2950** filename argument. ^The filename argument is interpreted as UTF-8 for
2951** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2952** order for sqlite3_open16(). ^(A [database connection] handle is usually
2953** returned in *ppDb, even if an error occurs.  The only exception is that
2954** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2955** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2956** object.)^ ^(If the database is opened (and/or created) successfully, then
2957** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
2958** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2959** an English language description of the error following a failure of any
2960** of the sqlite3_open() routines.
2962** ^The default encoding will be UTF-8 for databases created using
2963** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
2964** created using sqlite3_open16() will be UTF-16 in the native byte order.
2966** Whether or not an error occurs when it is opened, resources
2967** associated with the [database connection] handle should be released by
2968** passing it to [sqlite3_close()] when it is no longer required.
2970** The sqlite3_open_v2() interface works like sqlite3_open()
2971** except that it accepts two additional parameters for additional control
2972** over the new database connection.  ^(The flags parameter to
2973** sqlite3_open_v2() can take one of
2974** the following three values, optionally combined with the
2978** <dl>
2979** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2980** <dd>The database is opened in read-only mode.  If the database does not
2981** already exist, an error is returned.</dd>)^
2983** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2984** <dd>The database is opened for reading and writing if possible, or reading
2985** only if the file is write protected by the operating system.  In either
2986** case the database must already exist, otherwise an error is returned.</dd>)^
2989** <dd>The database is opened for reading and writing, and is created if
2990** it does not already exist. This is the behavior that is always used for
2991** sqlite3_open() and sqlite3_open16().</dd>)^
2992** </dl>
2994** If the 3rd parameter to sqlite3_open_v2() is not one of the
2995** combinations shown above optionally combined with other
2997** then the behavior is undefined.
2999** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
3000** opens in the multi-thread [threading mode] as long as the single-thread
3001** mode has not been set at compile-time or start-time.  ^If the
3002** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
3003** in the serialized [threading mode] unless single-thread was
3004** previously selected at compile-time or start-time.
3005** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
3006** eligible to use [shared cache mode], regardless of whether or not shared
3007** cache is enabled using [sqlite3_enable_shared_cache()].  ^The
3008** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
3009** participate in [shared cache mode] even if it is enabled.
3011** ^The fourth parameter to sqlite3_open_v2() is the name of the
3012** [sqlite3_vfs] object that defines the operating system interface that
3013** the new database connection should use.  ^If the fourth parameter is
3014** a NULL pointer then the default [sqlite3_vfs] object is used.
3016** ^If the filename is ":memory:", then a private, temporary in-memory database
3017** is created for the connection.  ^This in-memory database will vanish when
3018** the database connection is closed.  Future versions of SQLite might
3019** make use of additional special filenames that begin with the ":" character.
3020** It is recommended that when a database filename actually does begin with
3021** a ":" character you should prefix the filename with a pathname such as
3022** "./" to avoid ambiguity.
3024** ^If the filename is an empty string, then a private, temporary
3025** on-disk database will be created.  ^This private database will be
3026** automatically deleted as soon as the database connection is closed.
3028** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
3030** ^If [URI filename] interpretation is enabled, and the filename argument
3031** begins with "file:", then the filename is interpreted as a URI. ^URI
3032** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
3033** set in the fourth argument to sqlite3_open_v2(), or if it has
3034** been enabled globally using the [SQLITE_CONFIG_URI] option with the
3035** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
3036** As of SQLite version 3.7.7, URI filename interpretation is turned off
3037** by default, but future releases of SQLite might enable URI filename
3038** interpretation by default.  See "[URI filenames]" for additional
3039** information.
3041** URI filenames are parsed according to RFC 3986. ^If the URI contains an
3042** authority, then it must be either an empty string or the string
3043** "localhost". ^If the authority is not an empty string or "localhost", an
3044** error is returned to the caller. ^The fragment component of a URI, if
3045** present, is ignored.
3047** ^SQLite uses the path component of the URI as the name of the disk file
3048** which contains the database. ^If the path begins with a '/' character,
3049** then it is interpreted as an absolute path. ^If the path does not begin
3050** with a '/' (meaning that the authority section is omitted from the URI)
3051** then the path is interpreted as a relative path.
3052** ^(On windows, the first component of an absolute path
3053** is a drive specification (e.g. "C:").)^
3055** [[core URI query parameters]]
3056** The query component of a URI may contain parameters that are interpreted
3057** either by SQLite itself, or by a [VFS | custom VFS implementation].
3058** SQLite and its built-in [VFSes] interpret the
3059** following query parameters:
3061** <ul>
3062**   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
3063**     a VFS object that provides the operating system interface that should
3064**     be used to access the database file on disk. ^If this option is set to
3065**     an empty string the default VFS object is used. ^Specifying an unknown
3066**     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
3067**     present, then the VFS specified by the option takes precedence over
3068**     the value passed as the fourth parameter to sqlite3_open_v2().
3070**   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
3071**     "rwc", or "memory". Attempting to set it to any other value is
3072**     an error)^.
3073**     ^If "ro" is specified, then the database is opened for read-only
3074**     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
3075**     third argument to sqlite3_open_v2(). ^If the mode option is set to
3076**     "rw", then the database is opened for read-write (but not create)
3077**     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
3078**     been set. ^Value "rwc" is equivalent to setting both
3079**     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
3080**     set to "memory" then a pure [in-memory database] that never reads
3081**     or writes from disk is used. ^It is an error to specify a value for
3082**     the mode parameter that is less restrictive than that specified by
3083**     the flags passed in the third parameter to sqlite3_open_v2().
3085**   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
3086**     "private". ^Setting it to "shared" is equivalent to setting the
3087**     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
3088**     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
3089**     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
3090**     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
3091**     a URI filename, its value overrides any behavior requested by setting
3094**  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
3095**     [powersafe overwrite] property does or does not apply to the
3096**     storage media on which the database file resides.
3098**  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
3099**     which if set disables file locking in rollback journal modes.  This
3100**     is useful for accessing a database on a filesystem that does not
3101**     support locking.  Caution:  Database corruption might result if two
3102**     or more processes write to the same database and any one of those
3103**     processes uses nolock=1.
3105**  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
3106**     parameter that indicates that the database file is stored on
3107**     read-only media.  ^When immutable is set, SQLite assumes that the
3108**     database file cannot be changed, even by a process with higher
3109**     privilege, and so the database is opened read-only and all locking
3110**     and change detection is disabled.  Caution: Setting the immutable
3111**     property on a database file that does in fact change can result
3112**     in incorrect query results and/or [SQLITE_CORRUPT] errors.
3113**     See also: [SQLITE_IOCAP_IMMUTABLE].
3115** </ul>
3117** ^Specifying an unknown parameter in the query component of a URI is not an
3118** error.  Future versions of SQLite might understand additional query
3119** parameters.  See "[query parameters with special meaning to SQLite]" for
3120** additional information.
3122** [[URI filename examples]] <h3>URI filename examples</h3>
3124** <table border="1" align=center cellpadding=5>
3125** <tr><th> URI filenames <th> Results
3126** <tr><td> file:data.db <td>
3127**          Open the file "data.db" in the current directory.
3128** <tr><td> file:/home/fred/data.db<br>
3129**          file:///home/fred/data.db <br>
3130**          file://localhost/home/fred/data.db <br> <td>
3131**          Open the database file "/home/fred/data.db".
3132** <tr><td> file://darkstar/home/fred/data.db <td>
3133**          An error. "darkstar" is not a recognized authority.
3134** <tr><td style="white-space:nowrap">
3135**          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
3136**     <td> Windows only: Open the file "data.db" on fred's desktop on drive
3137**          C:. Note that the %20 escaping in this example is not strictly
3138**          necessary - space characters can be used literally
3139**          in URI filenames.
3140** <tr><td> file:data.db?mode=ro&cache=private <td>
3141**          Open file "data.db" in the current directory for read-only access.
3142**          Regardless of whether or not shared-cache mode is enabled by
3143**          default, use a private cache.
3144** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
3145**          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
3146**          that uses dot-files in place of posix advisory locking.
3147** <tr><td> file:data.db?mode=readonly <td>
3148**          An error. "readonly" is not a valid option for the "mode" parameter.
3149** </table>
3151** ^URI hexadecimal escape sequences (%HH) are supported within the path and
3152** query components of a URI. A hexadecimal escape sequence consists of a
3153** percent sign - "%" - followed by exactly two hexadecimal digits
3154** specifying an octet value. ^Before the path or query components of a
3155** URI filename are interpreted, they are encoded using UTF-8 and all
3156** hexadecimal escape sequences replaced by a single byte containing the
3157** corresponding octet. If this process generates an invalid UTF-8 encoding,
3158** the results are undefined.
3160** <b>Note to Windows users:</b>  The encoding used for the filename argument
3161** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
3162** codepage is currently defined.  Filenames containing international
3163** characters must be converted to UTF-8 prior to passing them into
3164** sqlite3_open() or sqlite3_open_v2().
3166** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
3167** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
3168** features that require the use of temporary files may fail.
3170** See also: [sqlite3_temp_directory]
3172SQLITE_API int SQLITE_STDCALL sqlite3_open(
3173  const char *filename,   /* Database filename (UTF-8) */
3174  sqlite3 **ppDb          /* OUT: SQLite db handle */
3176SQLITE_API int SQLITE_STDCALL sqlite3_open16(
3177  const void *filename,   /* Database filename (UTF-16) */
3178  sqlite3 **ppDb          /* OUT: SQLite db handle */
3180SQLITE_API int SQLITE_STDCALL sqlite3_open_v2(
3181  const char *filename,   /* Database filename (UTF-8) */
3182  sqlite3 **ppDb,         /* OUT: SQLite db handle */
3183  int flags,              /* Flags */
3184  const char *zVfs        /* Name of VFS module to use */
3188** CAPI3REF: Obtain Values For URI Parameters
3190** These are utility routines, useful to VFS implementations, that check
3191** to see if a database file was a URI that contained a specific query
3192** parameter, and if so obtains the value of that query parameter.
3194** If F is the database filename pointer passed into the xOpen() method of
3195** a VFS implementation when the flags parameter to xOpen() has one or
3196** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
3197** P is the name of the query parameter, then
3198** sqlite3_uri_parameter(F,P) returns the value of the P
3199** parameter if it exists or a NULL pointer if P does not appear as a
3200** query parameter on F.  If P is a query parameter of F
3201** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3202** a pointer to an empty string.
3204** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3205** parameter and returns true (1) or false (0) according to the value
3206** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3207** value of query parameter P is one of "yes", "true", or "on" in any
3208** case or if the value begins with a non-zero number.  The
3209** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3210** query parameter P is one of "no", "false", or "off" in any case or
3211** if the value begins with a numeric zero.  If P is not a query
3212** parameter on F or if the value of P is does not match any of the
3213** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3215** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3216** 64-bit signed integer and returns that integer, or D if P does not
3217** exist.  If the value of P is something other than an integer, then
3218** zero is returned.
3220** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3221** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
3222** is not a database file pathname pointer that SQLite passed into the xOpen
3223** VFS method, then the behavior of this routine is undefined and probably
3224** undesirable.
3226SQLITE_API const char *SQLITE_STDCALL sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3227SQLITE_API int SQLITE_STDCALL sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3228SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3232** CAPI3REF: Error Codes And Messages
3233** METHOD: sqlite3
3235** ^If the most recent sqlite3_* API call associated with
3236** [database connection] D failed, then the sqlite3_errcode(D) interface
3237** returns the numeric [result code] or [extended result code] for that
3238** API call.
3239** If the most recent API call was successful,
3240** then the return value from sqlite3_errcode() is undefined.
3241** ^The sqlite3_extended_errcode()
3242** interface is the same except that it always returns the
3243** [extended result code] even when extended result codes are
3244** disabled.
3246** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3247** text that describes the error, as either UTF-8 or UTF-16 respectively.
3248** ^(Memory to hold the error message string is managed internally.
3249** The application does not need to worry about freeing the result.
3250** However, the error string might be overwritten or deallocated by
3251** subsequent calls to other SQLite interface functions.)^
3253** ^The sqlite3_errstr() interface returns the English-language text
3254** that describes the [result code], as UTF-8.
3255** ^(Memory to hold the error message string is managed internally
3256** and must not be freed by the application)^.
3258** When the serialized [threading mode] is in use, it might be the
3259** case that a second error occurs on a separate thread in between
3260** the time of the first error and the call to these interfaces.
3261** When that happens, the second error will be reported since these
3262** interfaces always report the most recent result.  To avoid
3263** this, each thread can obtain exclusive use of the [database connection] D
3264** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3265** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3266** all calls to the interfaces listed here are completed.
3268** If an interface fails with SQLITE_MISUSE, that means the interface
3269** was invoked incorrectly by the application.  In that case, the
3270** error code and message may or may not be set.
3272SQLITE_API int SQLITE_STDCALL sqlite3_errcode(sqlite3 *db);
3273SQLITE_API int SQLITE_STDCALL sqlite3_extended_errcode(sqlite3 *db);
3274SQLITE_API const char *SQLITE_STDCALL sqlite3_errmsg(sqlite3*);
3275SQLITE_API const void *SQLITE_STDCALL sqlite3_errmsg16(sqlite3*);
3276SQLITE_API const char *SQLITE_STDCALL sqlite3_errstr(int);
3279** CAPI3REF: Prepared Statement Object
3280** KEYWORDS: {prepared statement} {prepared statements}
3282** An instance of this object represents a single SQL statement that
3283** has been compiled into binary form and is ready to be evaluated.
3285** Think of each SQL statement as a separate computer program.  The
3286** original SQL text is source code.  A prepared statement object
3287** is the compiled object code.  All SQL must be converted into a
3288** prepared statement before it can be run.
3290** The life-cycle of a prepared statement object usually goes like this:
3292** <ol>
3293** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
3294** <li> Bind values to [parameters] using the sqlite3_bind_*()
3295**      interfaces.
3296** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3297** <li> Reset the prepared statement using [sqlite3_reset()] then go back
3298**      to step 2.  Do this zero or more times.
3299** <li> Destroy the object using [sqlite3_finalize()].
3300** </ol>
3302typedef struct sqlite3_stmt sqlite3_stmt;
3305** CAPI3REF: Run-time Limits
3306** METHOD: sqlite3
3308** ^(This interface allows the size of various constructs to be limited
3309** on a connection by connection basis.  The first parameter is the
3310** [database connection] whose limit is to be set or queried.  The
3311** second parameter is one of the [limit categories] that define a
3312** class of constructs to be size limited.  The third parameter is the
3313** new limit for that construct.)^
3315** ^If the new limit is a negative number, the limit is unchanged.
3316** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3317** [limits | hard upper bound]
3318** set at compile-time by a C preprocessor macro called
3319** [limits | SQLITE_MAX_<i>NAME</i>].
3320** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3321** ^Attempts to increase a limit above its hard upper bound are
3322** silently truncated to the hard upper bound.
3324** ^Regardless of whether or not the limit was changed, the
3325** [sqlite3_limit()] interface returns the prior value of the limit.
3326** ^Hence, to find the current value of a limit without changing it,
3327** simply invoke this interface with the third parameter set to -1.
3329** Run-time limits are intended for use in applications that manage
3330** both their own internal database and also databases that are controlled
3331** by untrusted external sources.  An example application might be a
3332** web browser that has its own databases for storing history and
3333** separate databases controlled by JavaScript applications downloaded
3334** off the Internet.  The internal databases can be given the
3335** large, default limits.  Databases managed by external sources can
3336** be given much smaller limits designed to prevent a denial of service
3337** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
3338** interface to further control untrusted SQL.  The size of the database
3339** created by an untrusted script can be contained using the
3340** [max_page_count] [PRAGMA].
3342** New run-time limit categories may be added in future releases.
3344SQLITE_API int SQLITE_STDCALL sqlite3_limit(sqlite3*, int id, int newVal);
3347** CAPI3REF: Run-Time Limit Categories
3348** KEYWORDS: {limit category} {*limit categories}
3350** These constants define various performance limits
3351** that can be lowered at run-time using [sqlite3_limit()].
3352** The synopsis of the meanings of the various limits is shown below.
3353** Additional information is available at [limits | Limits in SQLite].
3355** <dl>
3357** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3360** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3363** <dd>The maximum number of columns in a table definition or in the
3364** result set of a [SELECT] or the maximum number of columns in an index
3365** or in an ORDER BY or GROUP BY clause.</dd>)^
3368** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3371** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3374** <dd>The maximum number of instructions in a virtual machine program
3375** used to implement an SQL statement.  This limit is not currently
3376** enforced, though that might be added in some future release of
3377** SQLite.</dd>)^
3380** <dd>The maximum number of arguments on a function.</dd>)^
3383** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3387** <dd>The maximum length of the pattern argument to the [LIKE] or
3388** [GLOB] operators.</dd>)^
3392** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3395** <dd>The maximum depth of recursion for triggers.</dd>)^
3398** <dd>The maximum number of auxiliary worker threads that a single
3399** [prepared statement] may start.</dd>)^
3400** </dl>
3402#define SQLITE_LIMIT_LENGTH                    0
3403#define SQLITE_LIMIT_SQL_LENGTH                1
3404#define SQLITE_LIMIT_COLUMN                    2
3405#define SQLITE_LIMIT_EXPR_DEPTH                3
3406#define SQLITE_LIMIT_COMPOUND_SELECT           4
3407#define SQLITE_LIMIT_VDBE_OP                   5
3408#define SQLITE_LIMIT_FUNCTION_ARG              6
3409#define SQLITE_LIMIT_ATTACHED                  7
3411#define SQLITE_LIMIT_VARIABLE_NUMBER           9
3412#define SQLITE_LIMIT_TRIGGER_DEPTH            10
3413#define SQLITE_LIMIT_WORKER_THREADS           11
3416** CAPI3REF: Compiling An SQL Statement
3417** KEYWORDS: {SQL statement compiler}
3418** METHOD: sqlite3
3419** CONSTRUCTOR: sqlite3_stmt
3421** To execute an SQL query, it must first be compiled into a byte-code
3422** program using one of these routines.
3424** The first argument, "db", is a [database connection] obtained from a
3425** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3426** [sqlite3_open16()].  The database connection must not have been closed.
3428** The second argument, "zSql", is the statement to be compiled, encoded
3429** as either UTF-8 or UTF-16.  The sqlite3_prepare() and sqlite3_prepare_v2()
3430** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
3431** use UTF-16.
3433** ^If the nByte argument is negative, then zSql is read up to the
3434** first zero terminator. ^If nByte is positive, then it is the
3435** number of bytes read from zSql.  ^If nByte is zero, then no prepared
3436** statement is generated.
3437** If the caller knows that the supplied string is nul-terminated, then
3438** there is a small performance advantage to passing an nByte parameter that
3439** is the number of bytes in the input string <i>including</i>
3440** the nul-terminator.
3442** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3443** past the end of the first SQL statement in zSql.  These routines only
3444** compile the first statement in zSql, so *pzTail is left pointing to
3445** what remains uncompiled.
3447** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3448** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
3449** to NULL.  ^If the input text contains no SQL (if the input is an empty
3450** string or a comment) then *ppStmt is set to NULL.
3451** The calling procedure is responsible for deleting the compiled
3452** SQL statement using [sqlite3_finalize()] after it has finished with it.
3453** ppStmt may not be NULL.
3455** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3456** otherwise an [error code] is returned.
3458** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
3459** recommended for all new programs. The two older interfaces are retained
3460** for backwards compatibility, but their use is discouraged.
3461** ^In the "v2" interfaces, the prepared statement
3462** that is returned (the [sqlite3_stmt] object) contains a copy of the
3463** original SQL text. This causes the [sqlite3_step()] interface to
3464** behave differently in three ways:
3466** <ol>
3467** <li>
3468** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3469** always used to do, [sqlite3_step()] will automatically recompile the SQL
3470** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3471** retries will occur before sqlite3_step() gives up and returns an error.
3472** </li>
3474** <li>
3475** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3476** [error codes] or [extended error codes].  ^The legacy behavior was that
3477** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3478** and the application would have to make a second call to [sqlite3_reset()]
3479** in order to find the underlying cause of the problem. With the "v2" prepare
3480** interfaces, the underlying reason for the error is returned immediately.
3481** </li>
3483** <li>
3484** ^If the specific value bound to [parameter | host parameter] in the
3485** WHERE clause might influence the choice of query plan for a statement,
3486** then the statement will be automatically recompiled, as if there had been
3487** a schema change, on the first  [sqlite3_step()] call following any change
3488** to the [sqlite3_bind_text | bindings] of that [parameter].
3489** ^The specific value of WHERE-clause [parameter] might influence the
3490** choice of query plan if the parameter is the left-hand side of a [LIKE]
3491** or [GLOB] operator or if the parameter is compared to an indexed column
3492** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3493** </li>
3494** </ol>
3496SQLITE_API int SQLITE_STDCALL sqlite3_prepare(
3497  sqlite3 *db,            /* Database handle */
3498  const char *zSql,       /* SQL statement, UTF-8 encoded */
3499  int nByte,              /* Maximum length of zSql in bytes. */
3500  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3501  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
3503SQLITE_API int SQLITE_STDCALL sqlite3_prepare_v2(
3504  sqlite3 *db,            /* Database handle */
3505  const char *zSql,       /* SQL statement, UTF-8 encoded */
3506  int nByte,              /* Maximum length of zSql in bytes. */
3507  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3508  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
3510SQLITE_API int SQLITE_STDCALL sqlite3_prepare16(
3511  sqlite3 *db,            /* Database handle */
3512  const void *zSql,       /* SQL statement, UTF-16 encoded */
3513  int nByte,              /* Maximum length of zSql in bytes. */
3514  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3515  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
3517SQLITE_API int SQLITE_STDCALL sqlite3_prepare16_v2(
3518  sqlite3 *db,            /* Database handle */
3519  const void *zSql,       /* SQL statement, UTF-16 encoded */
3520  int nByte,              /* Maximum length of zSql in bytes. */
3521  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3522  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
3526** CAPI3REF: Retrieving Statement SQL
3527** METHOD: sqlite3_stmt
3529** ^This interface can be used to retrieve a saved copy of the original
3530** SQL text used to create a [prepared statement] if that statement was
3531** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
3533SQLITE_API const char *SQLITE_STDCALL sqlite3_sql(sqlite3_stmt *pStmt);
3536** CAPI3REF: Determine If An SQL Statement Writes The Database
3537** METHOD: sqlite3_stmt
3539** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3540** and only if the [prepared statement] X makes no direct changes to
3541** the content of the database file.
3543** Note that [application-defined SQL functions] or
3544** [virtual tables] might change the database indirectly as a side effect.
3545** ^(For example, if an application defines a function "eval()" that
3546** calls [sqlite3_exec()], then the following SQL statement would
3547** change the database file through side-effects:
3549** <blockquote><pre>
3550**    SELECT eval('DELETE FROM t1') FROM t2;
3551** </pre></blockquote>
3553** But because the [SELECT] statement does not change the database file
3554** directly, sqlite3_stmt_readonly() would still return true.)^
3556** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3557** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3558** since the statements themselves do not actually modify the database but
3559** rather they control the timing of when other statements modify the
3560** database.  ^The [ATTACH] and [DETACH] statements also cause
3561** sqlite3_stmt_readonly() to return true since, while those statements
3562** change the configuration of a database connection, they do not make
3563** changes to the content of the database files on disk.
3565SQLITE_API int SQLITE_STDCALL sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3568** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3569** METHOD: sqlite3_stmt
3571** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3572** [prepared statement] S has been stepped at least once using
3573** [sqlite3_step(S)] but has not run to completion and/or has not
3574** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
3575** interface returns false if S is a NULL pointer.  If S is not a
3576** NULL pointer and is not a pointer to a valid [prepared statement]
3577** object, then the behavior is undefined and probably undesirable.
3579** This interface can be used in combination [sqlite3_next_stmt()]
3580** to locate all prepared statements associated with a database
3581** connection that are in need of being reset.  This can be used,
3582** for example, in diagnostic routines to search for prepared
3583** statements that are holding a transaction open.
3585SQLITE_API int SQLITE_STDCALL sqlite3_stmt_busy(sqlite3_stmt*);
3588** CAPI3REF: Dynamically Typed Value Object
3589** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3591** SQLite uses the sqlite3_value object to represent all values
3592** that can be stored in a database table. SQLite uses dynamic typing
3593** for the values it stores.  ^Values stored in sqlite3_value objects
3594** can be integers, floating point values, strings, BLOBs, or NULL.
3596** An sqlite3_value object may be either "protected" or "unprotected".
3597** Some interfaces require a protected sqlite3_value.  Other interfaces
3598** will accept either a protected or an unprotected sqlite3_value.
3599** Every interface that accepts sqlite3_value arguments specifies
3600** whether or not it requires a protected sqlite3_value.
3602** The terms "protected" and "unprotected" refer to whether or not
3603** a mutex is held.  An internal mutex is held for a protected
3604** sqlite3_value object but no mutex is held for an unprotected
3605** sqlite3_value object.  If SQLite is compiled to be single-threaded
3606** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3607** or if SQLite is run in one of reduced mutex modes
3609** then there is no distinction between protected and unprotected
3610** sqlite3_value objects and they can be used interchangeably.  However,
3611** for maximum code portability it is recommended that applications
3612** still make the distinction between protected and unprotected
3613** sqlite3_value objects even when not strictly required.
3615** ^The sqlite3_value objects that are passed as parameters into the
3616** implementation of [application-defined SQL functions] are protected.
3617** ^The sqlite3_value object returned by
3618** [sqlite3_column_value()] is unprotected.
3619** Unprotected sqlite3_value objects may only be used with
3620** [sqlite3_result_value()] and [sqlite3_bind_value()].
3621** The [sqlite3_value_blob | sqlite3_value_type()] family of
3622** interfaces require protected sqlite3_value objects.
3624typedef struct Mem sqlite3_value;
3627** CAPI3REF: SQL Function Context Object
3629** The context in which an SQL function executes is stored in an
3630** sqlite3_context object.  ^A pointer to an sqlite3_context object
3631** is always first parameter to [application-defined SQL functions].
3632** The application-defined SQL function implementation will pass this
3633** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3634** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3635** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3636** and/or [sqlite3_set_auxdata()].
3638typedef struct sqlite3_context sqlite3_context;
3641** CAPI3REF: Binding Values To Prepared Statements
3642** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3643** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3644** METHOD: sqlite3_stmt
3646** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3647** literals may be replaced by a [parameter] that matches one of following
3648** templates:
3650** <ul>
3651** <li>  ?
3652** <li>  ?NNN
3653** <li>  :VVV
3654** <li>  @VVV
3655** <li>  $VVV
3656** </ul>
3658** In the templates above, NNN represents an integer literal,
3659** and VVV represents an alphanumeric identifier.)^  ^The values of these
3660** parameters (also called "host parameter names" or "SQL parameters")
3661** can be set using the sqlite3_bind_*() routines defined here.
3663** ^The first argument to the sqlite3_bind_*() routines is always
3664** a pointer to the [sqlite3_stmt] object returned from
3665** [sqlite3_prepare_v2()] or its variants.
3667** ^The second argument is the index of the SQL parameter to be set.
3668** ^The leftmost SQL parameter has an index of 1.  ^When the same named
3669** SQL parameter is used more than once, second and subsequent
3670** occurrences have the same index as the first occurrence.
3671** ^The index for named parameters can be looked up using the
3672** [sqlite3_bind_parameter_index()] API if desired.  ^The index
3673** for "?NNN" parameters is the value of NNN.
3674** ^The NNN value must be between 1 and the [sqlite3_limit()]
3675** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3677** ^The third argument is the value to bind to the parameter.
3678** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3679** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3680** is ignored and the end result is the same as sqlite3_bind_null().
3682** ^(In those routines that have a fourth argument, its value is the
3683** number of bytes in the parameter.  To be clear: the value is the
3684** number of <u>bytes</u> in the value, not the number of characters.)^
3685** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3686** is negative, then the length of the string is
3687** the number of bytes up to the first zero terminator.
3688** If the fourth parameter to sqlite3_bind_blob() is negative, then
3689** the behavior is undefined.
3690** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3691** or sqlite3_bind_text16() or sqlite3_bind_text64() then
3692** that parameter must be the byte offset
3693** where the NUL terminator would occur assuming the string were NUL
3694** terminated.  If any NUL characters occur at byte offsets less than
3695** the value of the fourth parameter then the resulting string value will
3696** contain embedded NULs.  The result of expressions involving strings
3697** with embedded NULs is undefined.
3699** ^The fifth argument to the BLOB and string binding interfaces
3700** is a destructor used to dispose of the BLOB or
3701** string after SQLite has finished with it.  ^The destructor is called
3702** to dispose of the BLOB or string even if the call to bind API fails.
3703** ^If the fifth argument is
3704** the special value [SQLITE_STATIC], then SQLite assumes that the
3705** information is in static, unmanaged space and does not need to be freed.
3706** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3707** SQLite makes its own private copy of the data immediately, before
3708** the sqlite3_bind_*() routine returns.
3710** ^The sixth argument to sqlite3_bind_text64() must be one of
3712** to specify the encoding of the text in the third parameter.  If
3713** the sixth argument to sqlite3_bind_text64() is not one of the
3714** allowed values shown above, or if the text encoding is different
3715** from the encoding specified by the sixth parameter, then the behavior
3716** is undefined.
3718** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3719** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
3720** (just an integer to hold its size) while it is being processed.
3721** Zeroblobs are intended to serve as placeholders for BLOBs whose
3722** content is later written using
3723** [sqlite3_blob_open | incremental BLOB I/O] routines.
3724** ^A negative value for the zeroblob results in a zero-length BLOB.
3726** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3727** for the [prepared statement] or with a prepared statement for which
3728** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3729** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
3730** routine is passed a [prepared statement] that has been finalized, the
3731** result is undefined and probably harmful.
3733** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3734** ^Unbound parameters are interpreted as NULL.
3736** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3737** [error code] if anything goes wrong.
3738** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
3739** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
3741** ^[SQLITE_RANGE] is returned if the parameter
3742** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
3744** See also: [sqlite3_bind_parameter_count()],
3745** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3747SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3748SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
3749                        void(*)(void*));
3750SQLITE_API int SQLITE_STDCALL sqlite3_bind_double(sqlite3_stmt*, int, double);
3751SQLITE_API int SQLITE_STDCALL sqlite3_bind_int(sqlite3_stmt*, int, int);
3752SQLITE_API int SQLITE_STDCALL sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3753SQLITE_API int SQLITE_STDCALL sqlite3_bind_null(sqlite3_stmt*, int);
3754SQLITE_API int SQLITE_STDCALL sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
3755SQLITE_API int SQLITE_STDCALL sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3756SQLITE_API int SQLITE_STDCALL sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
3757                         void(*)(void*), unsigned char encoding);
3758SQLITE_API int SQLITE_STDCALL sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3759SQLITE_API int SQLITE_STDCALL sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3762** CAPI3REF: Number Of SQL Parameters
3763** METHOD: sqlite3_stmt
3765** ^This routine can be used to find the number of [SQL parameters]
3766** in a [prepared statement].  SQL parameters are tokens of the
3767** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3768** placeholders for values that are [sqlite3_bind_blob | bound]
3769** to the parameters at a later time.
3771** ^(This routine actually returns the index of the largest (rightmost)
3772** parameter. For all forms except ?NNN, this will correspond to the
3773** number of unique parameters.  If parameters of the ?NNN form are used,
3774** there may be gaps in the list.)^
3776** See also: [sqlite3_bind_blob|sqlite3_bind()],
3777** [sqlite3_bind_parameter_name()], and
3778** [sqlite3_bind_parameter_index()].
3780SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_count(sqlite3_stmt*);
3783** CAPI3REF: Name Of A Host Parameter
3784** METHOD: sqlite3_stmt
3786** ^The sqlite3_bind_parameter_name(P,N) interface returns
3787** the name of the N-th [SQL parameter] in the [prepared statement] P.
3788** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3789** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3790** respectively.
3791** In other words, the initial ":" or "$" or "@" or "?"
3792** is included as part of the name.)^
3793** ^Parameters of the form "?" without a following integer have no name
3794** and are referred to as "nameless" or "anonymous parameters".
3796** ^The first host parameter has an index of 1, not 0.
3798** ^If the value N is out of range or if the N-th parameter is
3799** nameless, then NULL is returned.  ^The returned string is
3800** always in UTF-8 encoding even if the named parameter was
3801** originally specified as UTF-16 in [sqlite3_prepare16()] or
3802** [sqlite3_prepare16_v2()].
3804** See also: [sqlite3_bind_blob|sqlite3_bind()],
3805** [sqlite3_bind_parameter_count()], and
3806** [sqlite3_bind_parameter_index()].
3808SQLITE_API const char *SQLITE_STDCALL sqlite3_bind_parameter_name(sqlite3_stmt*, int);
3811** CAPI3REF: Index Of A Parameter With A Given Name
3812** METHOD: sqlite3_stmt
3814** ^Return the index of an SQL parameter given its name.  ^The
3815** index value returned is suitable for use as the second
3816** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
3817** is returned if no matching parameter is found.  ^The parameter
3818** name must be given in UTF-8 even if the original statement
3819** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3821** See also: [sqlite3_bind_blob|sqlite3_bind()],
3822** [sqlite3_bind_parameter_count()], and
3823** [sqlite3_bind_parameter_index()].
3825SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
3828** CAPI3REF: Reset All Bindings On A Prepared Statement
3829** METHOD: sqlite3_stmt
3831** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3832** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3833** ^Use this routine to reset all host parameters to NULL.
3835SQLITE_API int SQLITE_STDCALL sqlite3_clear_bindings(sqlite3_stmt*);
3838** CAPI3REF: Number Of Columns In A Result Set
3839** METHOD: sqlite3_stmt
3841** ^Return the number of columns in the result set returned by the
3842** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3843** statement that does not return data (for example an [UPDATE]).
3845** See also: [sqlite3_data_count()]
3847SQLITE_API int SQLITE_STDCALL sqlite3_column_count(sqlite3_stmt *pStmt);
3850** CAPI3REF: Column Names In A Result Set
3851** METHOD: sqlite3_stmt
3853** ^These routines return the name assigned to a particular column
3854** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
3855** interface returns a pointer to a zero-terminated UTF-8 string
3856** and sqlite3_column_name16() returns a pointer to a zero-terminated
3857** UTF-16 string.  ^The first parameter is the [prepared statement]
3858** that implements the [SELECT] statement. ^The second parameter is the
3859** column number.  ^The leftmost column is number 0.
3861** ^The returned string pointer is valid until either the [prepared statement]
3862** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3863** reprepared by the first call to [sqlite3_step()] for a particular run
3864** or until the next call to
3865** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3867** ^If sqlite3_malloc() fails during the processing of either routine
3868** (for example during a conversion from UTF-8 to UTF-16) then a
3869** NULL pointer is returned.
3871** ^The name of a result column is the value of the "AS" clause for
3872** that column, if there is an AS clause.  If there is no AS clause
3873** then the name of the column is unspecified and may change from
3874** one release of SQLite to the next.
3876SQLITE_API const char *SQLITE_STDCALL sqlite3_column_name(sqlite3_stmt*, int N);
3877SQLITE_API const void *SQLITE_STDCALL sqlite3_column_name16(sqlite3_stmt*, int N);
3880** CAPI3REF: Source Of Data In A Query Result
3881** METHOD: sqlite3_stmt
3883** ^These routines provide a means to determine the database, table, and
3884** table column that is the origin of a particular result column in
3885** [SELECT] statement.
3886** ^The name of the database or table or column can be returned as
3887** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
3888** the database name, the _table_ routines return the table name, and
3889** the origin_ routines return the column name.
3890** ^The returned string is valid until the [prepared statement] is destroyed
3891** using [sqlite3_finalize()] or until the statement is automatically
3892** reprepared by the first call to [sqlite3_step()] for a particular run
3893** or until the same information is requested
3894** again in a different encoding.
3896** ^The names returned are the original un-aliased names of the
3897** database, table, and column.
3899** ^The first argument to these interfaces is a [prepared statement].
3900** ^These functions return information about the Nth result column returned by
3901** the statement, where N is the second function argument.
3902** ^The left-most column is column 0 for these routines.
3904** ^If the Nth column returned by the statement is an expression or
3905** subquery and is not a column value, then all of these functions return
3906** NULL.  ^These routine might also return NULL if a memory allocation error
3907** occurs.  ^Otherwise, they return the name of the attached database, table,
3908** or column that query result column was extracted from.
3910** ^As with all other SQLite APIs, those whose names end with "16" return
3911** UTF-16 encoded strings and the other functions return UTF-8.
3913** ^These APIs are only available if the library was compiled with the
3914** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3916** If two or more threads call one or more of these routines against the same
3917** prepared statement and column at the same time then the results are
3918** undefined.
3920** If two or more threads call one or more
3921** [sqlite3_column_database_name | column metadata interfaces]
3922** for the same [prepared statement] and result column
3923** at the same time then the results are undefined.
3925SQLITE_API const char *SQLITE_STDCALL sqlite3_column_database_name(sqlite3_stmt*,int);
3926SQLITE_API const void *SQLITE_STDCALL sqlite3_column_database_name16(sqlite3_stmt*,int);
3927SQLITE_API const char *SQLITE_STDCALL sqlite3_column_table_name(sqlite3_stmt*,int);
3928SQLITE_API const void *SQLITE_STDCALL sqlite3_column_table_name16(sqlite3_stmt*,int);
3929SQLITE_API const char *SQLITE_STDCALL sqlite3_column_origin_name(sqlite3_stmt*,int);
3930SQLITE_API const void *SQLITE_STDCALL sqlite3_column_origin_name16(sqlite3_stmt*,int);
3933** CAPI3REF: Declared Datatype Of A Query Result
3934** METHOD: sqlite3_stmt
3936** ^(The first parameter is a [prepared statement].
3937** If this statement is a [SELECT] statement and the Nth column of the
3938** returned result set of that [SELECT] is a table column (not an
3939** expression or subquery) then the declared type of the table
3940** column is returned.)^  ^If the Nth column of the result set is an
3941** expression or subquery, then a NULL pointer is returned.
3942** ^The returned string is always UTF-8 encoded.
3944** ^(For example, given the database schema:
3948** and the following statement to be compiled:
3950** SELECT c1 + 1, c1 FROM t1;
3952** this routine would return the string "VARIANT" for the second result
3953** column (i==1), and a NULL pointer for the first result column (i==0).)^
3955** ^SQLite uses dynamic run-time typing.  ^So just because a column
3956** is declared to contain a particular type does not mean that the
3957** data stored in that column is of the declared type.  SQLite is
3958** strongly typed, but the typing is dynamic not static.  ^Type
3959** is associated with individual values, not with the containers
3960** used to hold those values.
3962SQLITE_API const char *SQLITE_STDCALL sqlite3_column_decltype(sqlite3_stmt*,int);
3963SQLITE_API const void *SQLITE_STDCALL sqlite3_column_decltype16(sqlite3_stmt*,int);
3966** CAPI3REF: Evaluate An SQL Statement
3967** METHOD: sqlite3_stmt
3969** After a [prepared statement] has been prepared using either
3970** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3971** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3972** must be called one or more times to evaluate the statement.
3974** The details of the behavior of the sqlite3_step() interface depend
3975** on whether the statement was prepared using the newer "v2" interface
3976** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3977** interface [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
3978** new "v2" interface is recommended for new applications but the legacy
3979** interface will continue to be supported.
3981** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3983** ^With the "v2" interface, any of the other [result codes] or
3984** [extended result codes] might be returned as well.
3986** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3987** database locks it needs to do its job.  ^If the statement is a [COMMIT]
3988** or occurs outside of an explicit transaction, then you can retry the
3989** statement.  If the statement is not a [COMMIT] and occurs within an
3990** explicit transaction then you should rollback the transaction before
3991** continuing.
3993** ^[SQLITE_DONE] means that the statement has finished executing
3994** successfully.  sqlite3_step() should not be called again on this virtual
3995** machine without first calling [sqlite3_reset()] to reset the virtual
3996** machine back to its initial state.
3998** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3999** is returned each time a new row of data is ready for processing by the
4000** caller. The values may be accessed using the [column access functions].
4001** sqlite3_step() is called again to retrieve the next row of data.
4003** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
4004** violation) has occurred.  sqlite3_step() should not be called again on
4005** the VM. More information may be found by calling [sqlite3_errmsg()].
4006** ^With the legacy interface, a more specific error code (for example,
4008** can be obtained by calling [sqlite3_reset()] on the
4009** [prepared statement].  ^In the "v2" interface,
4010** the more specific error code is returned directly by sqlite3_step().
4012** [SQLITE_MISUSE] means that the this routine was called inappropriately.
4013** Perhaps it was called on a [prepared statement] that has
4014** already been [sqlite3_finalize | finalized] or on one that had
4015** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
4016** be the case that the same database connection is being used by two or
4017** more threads at the same moment in time.
4019** For all versions of SQLite up to and including, a call to
4020** [sqlite3_reset()] was required after sqlite3_step() returned anything
4021** other than [SQLITE_ROW] before any subsequent invocation of
4022** sqlite3_step().  Failure to reset the prepared statement using
4023** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
4024** sqlite3_step().  But after version, sqlite3_step() began
4025** calling [sqlite3_reset()] automatically in this circumstance rather
4026** than returning [SQLITE_MISUSE].  This is not considered a compatibility
4027** break because any application that ever receives an SQLITE_MISUSE error
4028** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
4029** can be used to restore the legacy behavior.
4031** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
4032** API always returns a generic error code, [SQLITE_ERROR], following any
4033** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
4034** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
4035** specific [error codes] that better describes the error.
4036** We admit that this is a goofy design.  The problem has been fixed
4037** with the "v2" interface.  If you prepare all of your SQL statements
4038** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
4039** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
4040** then the more specific [error codes] are returned directly
4041** by sqlite3_step().  The use of the "v2" interface is recommended.
4043SQLITE_API int SQLITE_STDCALL sqlite3_step(sqlite3_stmt*);
4046** CAPI3REF: Number of columns in a result set
4047** METHOD: sqlite3_stmt
4049** ^The sqlite3_data_count(P) interface returns the number of columns in the
4050** current row of the result set of [prepared statement] P.
4051** ^If prepared statement P does not have results ready to return
4052** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
4053** interfaces) then sqlite3_data_count(P) returns 0.
4054** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
4055** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
4056** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
4057** will return non-zero if previous call to [sqlite3_step](P) returned
4058** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
4059** where it always returns zero since each step of that multi-step
4060** pragma returns 0 columns of data.
4062** See also: [sqlite3_column_count()]
4064SQLITE_API int SQLITE_STDCALL sqlite3_data_count(sqlite3_stmt *pStmt);
4067** CAPI3REF: Fundamental Datatypes
4070** ^(Every value in SQLite has one of five fundamental datatypes:
4072** <ul>
4073** <li> 64-bit signed integer
4074** <li> 64-bit IEEE floating point number
4075** <li> string
4076** <li> BLOB
4077** <li> NULL
4078** </ul>)^
4080** These constants are codes for each of those types.
4082** Note that the SQLITE_TEXT constant was also used in SQLite version 2
4083** for a completely different meaning.  Software that links against both
4084** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
4087#define SQLITE_INTEGER  1
4088#define SQLITE_FLOAT    2
4089#define SQLITE_BLOB     4
4090#define SQLITE_NULL     5
4091#ifdef SQLITE_TEXT
4092# undef SQLITE_TEXT
4094# define SQLITE_TEXT     3
4096#define SQLITE3_TEXT     3
4099** CAPI3REF: Result Values From A Query
4100** KEYWORDS: {column access functions}
4101** METHOD: sqlite3_stmt
4103** These routines form the "result set" interface.
4105** ^These routines return information about a single column of the current
4106** result row of a query.  ^In every case the first argument is a pointer
4107** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
4108** that was returned from [sqlite3_prepare_v2()] or one of its variants)
4109** and the second argument is the index of the column for which information
4110** should be returned. ^The leftmost column of the result set has the index 0.
4111** ^The number of columns in the result can be determined using
4112** [sqlite3_column_count()].
4114** If the SQL statement does not currently point to a valid row, or if the
4115** column index is out of range, the result is undefined.
4116** These routines may only be called when the most recent call to
4117** [sqlite3_step()] has returned [SQLITE_ROW] and neither
4118** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
4119** If any of these routines are called after [sqlite3_reset()] or
4120** [sqlite3_finalize()] or after [sqlite3_step()] has returned
4121** something other than [SQLITE_ROW], the results are undefined.
4122** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
4123** are called from a different thread while any of these routines
4124** are pending, then the results are undefined.
4126** ^The sqlite3_column_type() routine returns the
4127** [SQLITE_INTEGER | datatype code] for the initial data type
4128** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
4130** returned by sqlite3_column_type() is only meaningful if no type
4131** conversions have occurred as described below.  After a type conversion,
4132** the value returned by sqlite3_column_type() is undefined.  Future
4133** versions of SQLite may change the behavior of sqlite3_column_type()
4134** following a type conversion.
4136** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
4137** routine returns the number of bytes in that BLOB or string.
4138** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
4139** the string to UTF-8 and then returns the number of bytes.
4140** ^If the result is a numeric value then sqlite3_column_bytes() uses
4141** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
4142** the number of bytes in that string.
4143** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
4145** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
4146** routine returns the number of bytes in that BLOB or string.
4147** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
4148** the string to UTF-16 and then returns the number of bytes.
4149** ^If the result is a numeric value then sqlite3_column_bytes16() uses
4150** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
4151** the number of bytes in that string.
4152** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
4154** ^The values returned by [sqlite3_column_bytes()] and
4155** [sqlite3_column_bytes16()] do not include the zero terminators at the end
4156** of the string.  ^For clarity: the values returned by
4157** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
4158** bytes in the string, not the number of characters.
4160** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
4161** even empty strings, are always zero-terminated.  ^The return
4162** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
4164** ^The object returned by [sqlite3_column_value()] is an
4165** [unprotected sqlite3_value] object.  An unprotected sqlite3_value object
4166** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
4167** If the [unprotected sqlite3_value] object returned by
4168** [sqlite3_column_value()] is used in any other way, including calls
4169** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
4170** or [sqlite3_value_bytes()], then the behavior is undefined.
4172** These routines attempt to convert the value where appropriate.  ^For
4173** example, if the internal representation is FLOAT and a text result
4174** is requested, [sqlite3_snprintf()] is used internally to perform the
4175** conversion automatically.  ^(The following table details the conversions
4176** that are applied:
4178** <blockquote>
4179** <table border="1">
4180** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
4182** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
4183** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
4184** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
4185** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
4186** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
4187** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
4188** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
4189** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
4190** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
4191** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
4192** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
4193** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
4194** <tr><td>  TEXT    <td>   BLOB    <td> No change
4195** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
4196** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
4197** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
4198** </table>
4199** </blockquote>)^
4201** The table above makes reference to standard C library functions atoi()
4202** and atof().  SQLite does not really use these functions.  It has its
4203** own equivalent internal routines.  The atoi() and atof() names are
4204** used in the table for brevity and because they are familiar to most
4205** C programmers.
4207** Note that when type conversions occur, pointers returned by prior
4208** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
4209** sqlite3_column_text16() may be invalidated.
4210** Type conversions and pointer invalidations might occur
4211** in the following cases:
4213** <ul>
4214** <li> The initial content is a BLOB and sqlite3_column_text() or
4215**      sqlite3_column_text16() is called.  A zero-terminator might
4216**      need to be added to the string.</li>
4217** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
4218**      sqlite3_column_text16() is called.  The content must be converted
4219**      to UTF-16.</li>
4220** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
4221**      sqlite3_column_text() is called.  The content must be converted
4222**      to UTF-8.</li>
4223** </ul>
4225** ^Conversions between UTF-16be and UTF-16le are always done in place and do
4226** not invalidate a prior pointer, though of course the content of the buffer
4227** that the prior pointer references will have been modified.  Other kinds
4228** of conversion are done in place when it is possible, but sometimes they
4229** are not possible and in those cases prior pointers are invalidated.
4231** The safest and easiest to remember policy is to invoke these routines
4232** in one of the following ways:
4234** <ul>
4235**  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
4236**  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
4237**  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
4238** </ul>
4240** In other words, you should call sqlite3_column_text(),
4241** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
4242** into the desired format, then invoke sqlite3_column_bytes() or
4243** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
4244** to sqlite3_column_text() or sqlite3_column_blob() with calls to
4245** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
4246** with calls to sqlite3_column_bytes().
4248** ^The pointers returned are valid until a type conversion occurs as
4249** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
4250** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
4251** and BLOBs is freed automatically.  Do <b>not</b> pass the pointers returned
4252** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
4253** [sqlite3_free()].
4255** ^(If a memory allocation error occurs during the evaluation of any
4256** of these routines, a default value is returned.  The default value
4257** is either the integer 0, the floating point number 0.0, or a NULL
4258** pointer.  Subsequent calls to [sqlite3_errcode()] will return
4259** [SQLITE_NOMEM].)^
4261SQLITE_API const void *SQLITE_STDCALL sqlite3_column_blob(sqlite3_stmt*, int iCol);
4262SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes(sqlite3_stmt*, int iCol);
4263SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
4264SQLITE_API double SQLITE_STDCALL sqlite3_column_double(sqlite3_stmt*, int iCol);
4265SQLITE_API int SQLITE_STDCALL sqlite3_column_int(sqlite3_stmt*, int iCol);
4266SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_column_int64(sqlite3_stmt*, int iCol);
4267SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_column_text(sqlite3_stmt*, int iCol);
4268SQLITE_API const void *SQLITE_STDCALL sqlite3_column_text16(sqlite3_stmt*, int iCol);
4269SQLITE_API int SQLITE_STDCALL sqlite3_column_type(sqlite3_stmt*, int iCol);
4270SQLITE_API sqlite3_value *SQLITE_STDCALL sqlite3_column_value(sqlite3_stmt*, int iCol);
4273** CAPI3REF: Destroy A Prepared Statement Object
4274** DESTRUCTOR: sqlite3_stmt
4276** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4277** ^If the most recent evaluation of the statement encountered no errors
4278** or if the statement is never been evaluated, then sqlite3_finalize() returns
4279** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
4280** sqlite3_finalize(S) returns the appropriate [error code] or
4281** [extended error code].
4283** ^The sqlite3_finalize(S) routine can be called at any point during
4284** the life cycle of [prepared statement] S:
4285** before statement S is ever evaluated, after
4286** one or more calls to [sqlite3_reset()], or after any call
4287** to [sqlite3_step()] regardless of whether or not the statement has
4288** completed execution.
4290** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4292** The application must finalize every [prepared statement] in order to avoid
4293** resource leaks.  It is a grievous error for the application to try to use
4294** a prepared statement after it has been finalized.  Any use of a prepared
4295** statement after it has been finalized can result in undefined and
4296** undesirable behavior such as segfaults and heap corruption.
4298SQLITE_API int SQLITE_STDCALL sqlite3_finalize(sqlite3_stmt *pStmt);
4301** CAPI3REF: Reset A Prepared Statement Object
4302** METHOD: sqlite3_stmt
4304** The sqlite3_reset() function is called to reset a [prepared statement]
4305** object back to its initial state, ready to be re-executed.
4306** ^Any SQL statement variables that had values bound to them using
4307** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4308** Use [sqlite3_clear_bindings()] to reset the bindings.
4310** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4311** back to the beginning of its program.
4313** ^If the most recent call to [sqlite3_step(S)] for the
4314** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4315** or if [sqlite3_step(S)] has never before been called on S,
4316** then [sqlite3_reset(S)] returns [SQLITE_OK].
4318** ^If the most recent call to [sqlite3_step(S)] for the
4319** [prepared statement] S indicated an error, then
4320** [sqlite3_reset(S)] returns an appropriate [error code].
4322** ^The [sqlite3_reset(S)] interface does not change the values
4323** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4325SQLITE_API int SQLITE_STDCALL sqlite3_reset(sqlite3_stmt *pStmt);
4328** CAPI3REF: Create Or Redefine SQL Functions
4329** KEYWORDS: {function creation routines}
4330** KEYWORDS: {application-defined SQL function}
4331** KEYWORDS: {application-defined SQL functions}
4332** METHOD: sqlite3
4334** ^These functions (collectively known as "function creation routines")
4335** are used to add SQL functions or aggregates or to redefine the behavior
4336** of existing SQL functions or aggregates.  The only differences between
4337** these routines are the text encoding expected for
4338** the second parameter (the name of the function being created)
4339** and the presence or absence of a destructor callback for
4340** the application data pointer.
4342** ^The first parameter is the [database connection] to which the SQL
4343** function is to be added.  ^If an application uses more than one database
4344** connection then application-defined SQL functions must be added
4345** to each database connection separately.
4347** ^The second parameter is the name of the SQL function to be created or
4348** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
4349** representation, exclusive of the zero-terminator.  ^Note that the name
4350** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4351** ^Any attempt to create a function with a longer name
4352** will result in [SQLITE_MISUSE] being returned.
4354** ^The third parameter (nArg)
4355** is the number of arguments that the SQL function or
4356** aggregate takes. ^If this parameter is -1, then the SQL function or
4357** aggregate may take any number of arguments between 0 and the limit
4358** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
4359** parameter is less than -1 or greater than 127 then the behavior is
4360** undefined.
4362** ^The fourth parameter, eTextRep, specifies what
4363** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4364** its parameters.  The application should set this parameter to
4365** [SQLITE_UTF16LE] if the function implementation invokes
4366** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4367** implementation invokes [sqlite3_value_text16be()] on an input, or
4368** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4369** otherwise.  ^The same SQL function may be registered multiple times using
4370** different preferred text encodings, with different implementations for
4371** each encoding.
4372** ^When multiple implementations of the same function are available, SQLite
4373** will pick the one that involves the least amount of data conversion.
4375** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4376** to signal that the function will always return the same result given
4377** the same inputs within a single SQL statement.  Most SQL functions are
4378** deterministic.  The built-in [random()] SQL function is an example of a
4379** function that is not deterministic.  The SQLite query planner is able to
4380** perform additional optimizations on deterministic functions, so use
4381** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4383** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
4384** function can gain access to this pointer using [sqlite3_user_data()].)^
4386** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
4387** pointers to C-language functions that implement the SQL function or
4388** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4389** callback only; NULL pointers must be passed as the xStep and xFinal
4390** parameters. ^An aggregate SQL function requires an implementation of xStep
4391** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4392** SQL function or aggregate, pass NULL pointers for all three function
4393** callbacks.
4395** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
4396** then it is destructor for the application data pointer.
4397** The destructor is invoked when the function is deleted, either by being
4398** overloaded or when the database connection closes.)^
4399** ^The destructor is also invoked if the call to
4400** sqlite3_create_function_v2() fails.
4401** ^When the destructor callback of the tenth parameter is invoked, it
4402** is passed a single argument which is a copy of the application data
4403** pointer which was the fifth parameter to sqlite3_create_function_v2().
4405** ^It is permitted to register multiple implementations of the same
4406** functions with the same name but with either differing numbers of
4407** arguments or differing preferred text encodings.  ^SQLite will use
4408** the implementation that most closely matches the way in which the
4409** SQL function is used.  ^A function implementation with a non-negative
4410** nArg parameter is a better match than a function implementation with
4411** a negative nArg.  ^A function where the preferred text encoding
4412** matches the database encoding is a better
4413** match than a function where the encoding is different.
4414** ^A function where the encoding difference is between UTF16le and UTF16be
4415** is a closer match than a function where the encoding difference is
4416** between UTF8 and UTF16.
4418** ^Built-in functions may be overloaded by new application-defined functions.
4420** ^An application-defined function is permitted to call other
4421** SQLite interfaces.  However, such calls must not
4422** close the database connection nor finalize or reset the prepared
4423** statement in which the function is running.
4425SQLITE_API int SQLITE_STDCALL sqlite3_create_function(
4426  sqlite3 *db,
4427  const char *zFunctionName,
4428  int nArg,
4429  int eTextRep,
4430  void *pApp,
4431  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4432  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4433  void (*xFinal)(sqlite3_context*)
4435SQLITE_API int SQLITE_STDCALL sqlite3_create_function16(
4436  sqlite3 *db,
4437  const void *zFunctionName,
4438  int nArg,
4439  int eTextRep,
4440  void *pApp,
4441  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4442  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4443  void (*xFinal)(sqlite3_context*)
4445SQLITE_API int SQLITE_STDCALL sqlite3_create_function_v2(
4446  sqlite3 *db,
4447  const char *zFunctionName,
4448  int nArg,
4449  int eTextRep,
4450  void *pApp,
4451  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4452  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4453  void (*xFinal)(sqlite3_context*),
4454  void(*xDestroy)(void*)
4458** CAPI3REF: Text Encodings
4460** These constant define integer codes that represent the various
4461** text encodings supported by SQLite.
4463#define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
4464#define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
4465#define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
4466#define SQLITE_UTF16          4    /* Use native byte order */
4467#define SQLITE_ANY            5    /* Deprecated */
4468#define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
4471** CAPI3REF: Function Flags
4473** These constants may be ORed together with the
4474** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4475** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4476** [sqlite3_create_function_v2()].
4478#define SQLITE_DETERMINISTIC    0x800
4481** CAPI3REF: Deprecated Functions
4484** These functions are [deprecated].  In order to maintain
4485** backwards compatibility with older code, these functions continue
4486** to be supported.  However, new applications should avoid
4487** the use of these functions.  To encourage programmers to avoid
4488** these functions, we will not explain what they do.
4491SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_aggregate_count(sqlite3_context*);
4492SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_expired(sqlite3_stmt*);
4493SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4494SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_global_recover(void);
4495SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_thread_cleanup(void);
4496SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4497                      void*,sqlite3_int64);
4501** CAPI3REF: Obtaining SQL Function Parameter Values
4502** METHOD: sqlite3_value
4504** The C-language implementation of SQL functions and aggregates uses
4505** this set of interface routines to access the parameter values on
4506** the function or aggregate.
4508** The xFunc (for scalar functions) or xStep (for aggregates) parameters
4509** to [sqlite3_create_function()] and [sqlite3_create_function16()]
4510** define callbacks that implement the SQL functions and aggregates.
4511** The 3rd parameter to these callbacks is an array of pointers to
4512** [protected sqlite3_value] objects.  There is one [sqlite3_value] object for
4513** each parameter to the SQL function.  These routines are used to
4514** extract values from the [sqlite3_value] objects.
4516** These routines work only with [protected sqlite3_value] objects.
4517** Any attempt to use these routines on an [unprotected sqlite3_value]
4518** object results in undefined behavior.
4520** ^These routines work just like the corresponding [column access functions]
4521** except that these routines take a single [protected sqlite3_value] object
4522** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4524** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4525** in the native byte-order of the host machine.  ^The
4526** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4527** extract UTF-16 strings as big-endian and little-endian respectively.
4529** ^(The sqlite3_value_numeric_type() interface attempts to apply
4530** numeric affinity to the value.  This means that an attempt is
4531** made to convert the value to an integer or floating point.  If
4532** such a conversion is possible without loss of information (in other
4533** words, if the value is a string that looks like a number)
4534** then the conversion is performed.  Otherwise no conversion occurs.
4535** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4537** Please pay particular attention to the fact that the pointer returned
4538** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4539** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4540** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4541** or [sqlite3_value_text16()].
4543** These routines must be called from the same thread as
4544** the SQL function that supplied the [sqlite3_value*] parameters.
4546SQLITE_API const void *SQLITE_STDCALL sqlite3_value_blob(sqlite3_value*);
4547SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes(sqlite3_value*);
4548SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes16(sqlite3_value*);
4549SQLITE_API double SQLITE_STDCALL sqlite3_value_double(sqlite3_value*);
4550SQLITE_API int SQLITE_STDCALL sqlite3_value_int(sqlite3_value*);
4551SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_value_int64(sqlite3_value*);
4552SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_value_text(sqlite3_value*);
4553SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16(sqlite3_value*);
4554SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16le(sqlite3_value*);
4555SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16be(sqlite3_value*);
4556SQLITE_API int SQLITE_STDCALL sqlite3_value_type(sqlite3_value*);
4557SQLITE_API int SQLITE_STDCALL sqlite3_value_numeric_type(sqlite3_value*);
4560** CAPI3REF: Obtain Aggregate Function Context
4561** METHOD: sqlite3_context
4563** Implementations of aggregate SQL functions use this
4564** routine to allocate memory for storing their state.
4566** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4567** for a particular aggregate function, SQLite
4568** allocates N of memory, zeroes out that memory, and returns a pointer
4569** to the new memory. ^On second and subsequent calls to
4570** sqlite3_aggregate_context() for the same aggregate function instance,
4571** the same buffer is returned.  Sqlite3_aggregate_context() is normally
4572** called once for each invocation of the xStep callback and then one
4573** last time when the xFinal callback is invoked.  ^(When no rows match
4574** an aggregate query, the xStep() callback of the aggregate function
4575** implementation is never called and xFinal() is called exactly once.
4576** In those cases, sqlite3_aggregate_context() might be called for the
4577** first time from within xFinal().)^
4579** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
4580** when first called if N is less than or equal to zero or if a memory
4581** allocate error occurs.
4583** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4584** determined by the N parameter on first successful call.  Changing the
4585** value of N in subsequent call to sqlite3_aggregate_context() within
4586** the same aggregate function instance will not resize the memory
4587** allocation.)^  Within the xFinal callback, it is customary to set
4588** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
4589** pointless memory allocations occur.
4591** ^SQLite automatically frees the memory allocated by
4592** sqlite3_aggregate_context() when the aggregate query concludes.
4594** The first parameter must be a copy of the
4595** [sqlite3_context | SQL function context] that is the first parameter
4596** to the xStep or xFinal callback routine that implements the aggregate
4597** function.
4599** This routine must be called from the same thread in which
4600** the aggregate SQL function is running.
4602SQLITE_API void *SQLITE_STDCALL sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4605** CAPI3REF: User Data For Functions
4606** METHOD: sqlite3_context
4608** ^The sqlite3_user_data() interface returns a copy of
4609** the pointer that was the pUserData parameter (the 5th parameter)
4610** of the [sqlite3_create_function()]
4611** and [sqlite3_create_function16()] routines that originally
4612** registered the application defined function.
4614** This routine must be called from the same thread in which
4615** the application-defined function is running.
4617SQLITE_API void *SQLITE_STDCALL sqlite3_user_data(sqlite3_context*);
4620** CAPI3REF: Database Connection For Functions
4621** METHOD: sqlite3_context
4623** ^The sqlite3_context_db_handle() interface returns a copy of
4624** the pointer to the [database connection] (the 1st parameter)
4625** of the [sqlite3_create_function()]
4626** and [sqlite3_create_function16()] routines that originally
4627** registered the application defined function.
4629SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_context_db_handle(sqlite3_context*);
4632** CAPI3REF: Function Auxiliary Data
4633** METHOD: sqlite3_context
4635** These functions may be used by (non-aggregate) SQL functions to
4636** associate metadata with argument values. If the same value is passed to
4637** multiple invocations of the same SQL function during query execution, under
4638** some circumstances the associated metadata may be preserved.  An example
4639** of where this might be useful is in a regular-expression matching
4640** function. The compiled version of the regular expression can be stored as
4641** metadata associated with the pattern string.
4642** Then as long as the pattern string remains the same,
4643** the compiled regular expression can be reused on multiple
4644** invocations of the same function.
4646** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
4647** associated by the sqlite3_set_auxdata() function with the Nth argument
4648** value to the application-defined function. ^If there is no metadata
4649** associated with the function argument, this sqlite3_get_auxdata() interface
4650** returns a NULL pointer.
4652** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
4653** argument of the application-defined function.  ^Subsequent
4654** calls to sqlite3_get_auxdata(C,N) return P from the most recent
4655** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
4656** NULL if the metadata has been discarded.
4657** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
4658** SQLite will invoke the destructor function X with parameter P exactly
4659** once, when the metadata is discarded.
4660** SQLite is free to discard the metadata at any time, including: <ul>
4661** <li> when the corresponding function parameter changes, or
4662** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
4663**      SQL statement, or
4664** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or
4665** <li> during the original sqlite3_set_auxdata() call when a memory
4666**      allocation error occurs. </ul>)^
4668** Note the last bullet in particular.  The destructor X in
4669** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
4670** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
4671** should be called near the end of the function implementation and the
4672** function implementation should not make any use of P after
4673** sqlite3_set_auxdata() has been called.
4675** ^(In practice, metadata is preserved between function calls for
4676** function parameters that are compile-time constants, including literal
4677** values and [parameters] and expressions composed from the same.)^
4679** These routines must be called from the same thread in which
4680** the SQL function is running.
4682SQLITE_API void *SQLITE_STDCALL sqlite3_get_auxdata(sqlite3_context*, int N);
4683SQLITE_API void SQLITE_STDCALL sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
4687** CAPI3REF: Constants Defining Special Destructor Behavior
4689** These are special values for the destructor that is passed in as the
4690** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
4691** argument is SQLITE_STATIC, it means that the content pointer is constant
4692** and will never change.  It does not need to be destroyed.  ^The
4693** SQLITE_TRANSIENT value means that the content will likely change in
4694** the near future and that SQLite should make its own private copy of
4695** the content before returning.
4697** The typedef is necessary to work around problems in certain
4698** C++ compilers.
4700typedef void (*sqlite3_destructor_type)(void*);
4701#define SQLITE_STATIC      ((sqlite3_destructor_type)0)
4702#define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
4705** CAPI3REF: Setting The Result Of An SQL Function
4706** METHOD: sqlite3_context
4708** These routines are used by the xFunc or xFinal callbacks that
4709** implement SQL functions and aggregates.  See
4710** [sqlite3_create_function()] and [sqlite3_create_function16()]
4711** for additional information.
4713** These functions work very much like the [parameter binding] family of
4714** functions used to bind values to host parameters in prepared statements.
4715** Refer to the [SQL parameter] documentation for additional information.
4717** ^The sqlite3_result_blob() interface sets the result from
4718** an application-defined function to be the BLOB whose content is pointed
4719** to by the second parameter and which is N bytes long where N is the
4720** third parameter.
4722** ^The sqlite3_result_zeroblob() interfaces set the result of
4723** the application-defined function to be a BLOB containing all zero
4724** bytes and N bytes in size, where N is the value of the 2nd parameter.
4726** ^The sqlite3_result_double() interface sets the result from
4727** an application-defined function to be a floating point value specified
4728** by its 2nd argument.
4730** ^The sqlite3_result_error() and sqlite3_result_error16() functions
4731** cause the implemented SQL function to throw an exception.
4732** ^SQLite uses the string pointed to by the
4733** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
4734** as the text of an error message.  ^SQLite interprets the error
4735** message string from sqlite3_result_error() as UTF-8. ^SQLite
4736** interprets the string from sqlite3_result_error16() as UTF-16 in native
4737** byte order.  ^If the third parameter to sqlite3_result_error()
4738** or sqlite3_result_error16() is negative then SQLite takes as the error
4739** message all text up through the first zero character.
4740** ^If the third parameter to sqlite3_result_error() or
4741** sqlite3_result_error16() is non-negative then SQLite takes that many
4742** bytes (not characters) from the 2nd parameter as the error message.
4743** ^The sqlite3_result_error() and sqlite3_result_error16()
4744** routines make a private copy of the error message text before
4745** they return.  Hence, the calling function can deallocate or
4746** modify the text after they return without harm.
4747** ^The sqlite3_result_error_code() function changes the error code
4748** returned by SQLite as a result of an error in a function.  ^By default,
4749** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
4750** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
4752** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
4753** error indicating that a string or BLOB is too long to represent.
4755** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
4756** error indicating that a memory allocation failed.
4758** ^The sqlite3_result_int() interface sets the return value
4759** of the application-defined function to be the 32-bit signed integer
4760** value given in the 2nd argument.
4761** ^The sqlite3_result_int64() interface sets the return value
4762** of the application-defined function to be the 64-bit signed integer
4763** value given in the 2nd argument.
4765** ^The sqlite3_result_null() interface sets the return value
4766** of the application-defined function to be NULL.
4768** ^The sqlite3_result_text(), sqlite3_result_text16(),
4769** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
4770** set the return value of the application-defined function to be
4771** a text string which is represented as UTF-8, UTF-16 native byte order,
4772** UTF-16 little endian, or UTF-16 big endian, respectively.
4773** ^The sqlite3_result_text64() interface sets the return value of an
4774** application-defined function to be a text string in an encoding
4775** specified by the fifth (and last) parameter, which must be one
4777** ^SQLite takes the text result from the application from
4778** the 2nd parameter of the sqlite3_result_text* interfaces.
4779** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4780** is negative, then SQLite takes result text from the 2nd parameter
4781** through the first zero character.
4782** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4783** is non-negative, then as many bytes (not characters) of the text
4784** pointed to by the 2nd parameter are taken as the application-defined
4785** function result.  If the 3rd parameter is non-negative, then it
4786** must be the byte offset into the string where the NUL terminator would
4787** appear if the string where NUL terminated.  If any NUL characters occur
4788** in the string at a byte offset that is less than the value of the 3rd
4789** parameter, then the resulting string will contain embedded NULs and the
4790** result of expressions operating on strings with embedded NULs is undefined.
4791** ^If the 4th parameter to the sqlite3_result_text* interfaces
4792** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4793** function as the destructor on the text or BLOB result when it has
4794** finished using that result.
4795** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4796** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4797** assumes that the text or BLOB result is in constant space and does not
4798** copy the content of the parameter nor call a destructor on the content
4799** when it has finished using that result.
4800** ^If the 4th parameter to the sqlite3_result_text* interfaces
4801** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4802** then SQLite makes a copy of the result into space obtained from
4803** from [sqlite3_malloc()] before it returns.
4805** ^The sqlite3_result_value() interface sets the result of
4806** the application-defined function to be a copy the
4807** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
4808** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4809** so that the [sqlite3_value] specified in the parameter may change or
4810** be deallocated after sqlite3_result_value() returns without harm.
4811** ^A [protected sqlite3_value] object may always be used where an
4812** [unprotected sqlite3_value] object is required, so either
4813** kind of [sqlite3_value] object can be used with this interface.
4815** If these routines are called from within the different thread
4816** than the one containing the application-defined function that received
4817** the [sqlite3_context] pointer, the results are undefined.
4819SQLITE_API void SQLITE_STDCALL sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4820SQLITE_API void SQLITE_STDCALL sqlite3_result_blob64(sqlite3_context*,const void*,
4821                           sqlite3_uint64,void(*)(void*));
4822SQLITE_API void SQLITE_STDCALL sqlite3_result_double(sqlite3_context*, double);
4823SQLITE_API void SQLITE_STDCALL sqlite3_result_error(sqlite3_context*, const char*, int);
4824SQLITE_API void SQLITE_STDCALL sqlite3_result_error16(sqlite3_context*, const void*, int);
4825SQLITE_API void SQLITE_STDCALL sqlite3_result_error_toobig(sqlite3_context*);
4826SQLITE_API void SQLITE_STDCALL sqlite3_result_error_nomem(sqlite3_context*);
4827SQLITE_API void SQLITE_STDCALL sqlite3_result_error_code(sqlite3_context*, int);
4828SQLITE_API void SQLITE_STDCALL sqlite3_result_int(sqlite3_context*, int);
4829SQLITE_API void SQLITE_STDCALL sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4830SQLITE_API void SQLITE_STDCALL sqlite3_result_null(sqlite3_context*);
4831SQLITE_API void SQLITE_STDCALL sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4832SQLITE_API void SQLITE_STDCALL sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
4833                           void(*)(void*), unsigned char encoding);
4834SQLITE_API void SQLITE_STDCALL sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4835SQLITE_API void SQLITE_STDCALL sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4836SQLITE_API void SQLITE_STDCALL sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4837SQLITE_API void SQLITE_STDCALL sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4838SQLITE_API void SQLITE_STDCALL sqlite3_result_zeroblob(sqlite3_context*, int n);
4841** CAPI3REF: Define New Collating Sequences
4842** METHOD: sqlite3
4844** ^These functions add, remove, or modify a [collation] associated
4845** with the [database connection] specified as the first argument.
4847** ^The name of the collation is a UTF-8 string
4848** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4849** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4850** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4851** considered to be the same name.
4853** ^(The third argument (eTextRep) must be one of the constants:
4854** <ul>
4855** <li> [SQLITE_UTF8],
4856** <li> [SQLITE_UTF16LE],
4857** <li> [SQLITE_UTF16BE],
4858** <li> [SQLITE_UTF16], or
4859** <li> [SQLITE_UTF16_ALIGNED].
4860** </ul>)^
4861** ^The eTextRep argument determines the encoding of strings passed
4862** to the collating function callback, xCallback.
4863** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4864** force strings to be UTF16 with native byte order.
4865** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4866** on an even byte address.
4868** ^The fourth argument, pArg, is an application data pointer that is passed
4869** through as the first argument to the collating function callback.
4871** ^The fifth argument, xCallback, is a pointer to the collating function.
4872** ^Multiple collating functions can be registered using the same name but
4873** with different eTextRep parameters and SQLite will use whichever
4874** function requires the least amount of data transformation.
4875** ^If the xCallback argument is NULL then the collating function is
4876** deleted.  ^When all collating functions having the same name are deleted,
4877** that collation is no longer usable.
4879** ^The collating function callback is invoked with a copy of the pArg
4880** application data pointer and with two strings in the encoding specified
4881** by the eTextRep argument.  The collating function must return an
4882** integer that is negative, zero, or positive
4883** if the first string is less than, equal to, or greater than the second,
4884** respectively.  A collating function must always return the same answer
4885** given the same inputs.  If two or more collating functions are registered
4886** to the same collation name (using different eTextRep values) then all
4887** must give an equivalent answer when invoked with equivalent strings.
4888** The collating function must obey the following properties for all
4889** strings A, B, and C:
4891** <ol>
4892** <li> If A==B then B==A.
4893** <li> If A==B and B==C then A==C.
4894** <li> If A&lt;B THEN B&gt;A.
4895** <li> If A&lt;B and B&lt;C then A&lt;C.
4896** </ol>
4898** If a collating function fails any of the above constraints and that
4899** collating function is  registered and used, then the behavior of SQLite
4900** is undefined.
4902** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4903** with the addition that the xDestroy callback is invoked on pArg when
4904** the collating function is deleted.
4905** ^Collating functions are deleted when they are overridden by later
4906** calls to the collation creation functions or when the
4907** [database connection] is closed using [sqlite3_close()].
4909** ^The xDestroy callback is <u>not</u> called if the
4910** sqlite3_create_collation_v2() function fails.  Applications that invoke
4911** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4912** check the return code and dispose of the application data pointer
4913** themselves rather than expecting SQLite to deal with it for them.
4914** This is different from every other SQLite interface.  The inconsistency
4915** is unfortunate but cannot be changed without breaking backwards
4916** compatibility.
4918** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4920SQLITE_API int SQLITE_STDCALL sqlite3_create_collation(
4921  sqlite3*,
4922  const char *zName,
4923  int eTextRep,
4924  void *pArg,
4925  int(*xCompare)(void*,int,const void*,int,const void*)
4927SQLITE_API int SQLITE_STDCALL sqlite3_create_collation_v2(
4928  sqlite3*,
4929  const char *zName,
4930  int eTextRep,
4931  void *pArg,
4932  int(*xCompare)(void*,int,const void*,int,const void*),
4933  void(*xDestroy)(void*)
4935SQLITE_API int SQLITE_STDCALL sqlite3_create_collation16(
4936  sqlite3*,
4937  const void *zName,
4938  int eTextRep,
4939  void *pArg,
4940  int(*xCompare)(void*,int,const void*,int,const void*)
4944** CAPI3REF: Collation Needed Callbacks
4945** METHOD: sqlite3
4947** ^To avoid having to register all collation sequences before a database
4948** can be used, a single callback function may be registered with the
4949** [database connection] to be invoked whenever an undefined collation
4950** sequence is required.
4952** ^If the function is registered using the sqlite3_collation_needed() API,
4953** then it is passed the names of undefined collation sequences as strings
4954** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4955** the names are passed as UTF-16 in machine native byte order.
4956** ^A call to either function replaces the existing collation-needed callback.
4958** ^(When the callback is invoked, the first argument passed is a copy
4959** of the second argument to sqlite3_collation_needed() or
4960** sqlite3_collation_needed16().  The second argument is the database
4961** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4962** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4963** sequence function required.  The fourth parameter is the name of the
4964** required collation sequence.)^
4966** The callback function should register the desired collation using
4967** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4968** [sqlite3_create_collation_v2()].
4970SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed(
4971  sqlite3*,
4972  void*,
4973  void(*)(void*,sqlite3*,int eTextRep,const char*)
4975SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed16(
4976  sqlite3*,
4977  void*,
4978  void(*)(void*,sqlite3*,int eTextRep,const void*)
4983** Specify the key for an encrypted database.  This routine should be
4984** called right after sqlite3_open().
4986** The code to implement this API is not available in the public release
4987** of SQLite.
4989SQLITE_API int SQLITE_STDCALL sqlite3_key(
4990  sqlite3 *db,                   /* Database to be rekeyed */
4991  const void *pKey, int nKey     /* The key */
4993SQLITE_API int SQLITE_STDCALL sqlite3_key_v2(
4994  sqlite3 *db,                   /* Database to be rekeyed */
4995  const char *zDbName,           /* Name of the database */
4996  const void *pKey, int nKey     /* The key */
5000** Change the key on an open database.  If the current database is not
5001** encrypted, this routine will encrypt it.  If pNew==0 or nNew==0, the
5002** database is decrypted.
5004** The code to implement this API is not available in the public release
5005** of SQLite.
5007SQLITE_API int SQLITE_STDCALL sqlite3_rekey(
5008  sqlite3 *db,                   /* Database to be rekeyed */
5009  const void *pKey, int nKey     /* The new key */
5011SQLITE_API int SQLITE_STDCALL sqlite3_rekey_v2(
5012  sqlite3 *db,                   /* Database to be rekeyed */
5013  const char *zDbName,           /* Name of the database */
5014  const void *pKey, int nKey     /* The new key */
5018** Specify the activation key for a SEE database.  Unless
5019** activated, none of the SEE routines will work.
5021SQLITE_API void SQLITE_STDCALL sqlite3_activate_see(
5022  const char *zPassPhrase        /* Activation phrase */
5028** Specify the activation key for a CEROD database.  Unless
5029** activated, none of the CEROD routines will work.
5031SQLITE_API void SQLITE_STDCALL sqlite3_activate_cerod(
5032  const char *zPassPhrase        /* Activation phrase */
5037** CAPI3REF: Suspend Execution For A Short Time
5039** The sqlite3_sleep() function causes the current thread to suspend execution
5040** for at least a number of milliseconds specified in its parameter.
5042** If the operating system does not support sleep requests with
5043** millisecond time resolution, then the time will be rounded up to
5044** the nearest second. The number of milliseconds of sleep actually
5045** requested from the operating system is returned.
5047** ^SQLite implements this interface by calling the xSleep()
5048** method of the default [sqlite3_vfs] object.  If the xSleep() method
5049** of the default VFS is not implemented correctly, or not implemented at
5050** all, then the behavior of sqlite3_sleep() may deviate from the description
5051** in the previous paragraphs.
5053SQLITE_API int SQLITE_STDCALL sqlite3_sleep(int);
5056** CAPI3REF: Name Of The Folder Holding Temporary Files
5058** ^(If this global variable is made to point to a string which is
5059** the name of a folder (a.k.a. directory), then all temporary files
5060** created by SQLite when using a built-in [sqlite3_vfs | VFS]
5061** will be placed in that directory.)^  ^If this variable
5062** is a NULL pointer, then SQLite performs a search for an appropriate
5063** temporary file directory.
5065** Applications are strongly discouraged from using this global variable.
5066** It is required to set a temporary folder on Windows Runtime (WinRT).
5067** But for all other platforms, it is highly recommended that applications
5068** neither read nor write this variable.  This global variable is a relic
5069** that exists for backwards compatibility of legacy applications and should
5070** be avoided in new projects.
5072** It is not safe to read or modify this variable in more than one
5073** thread at a time.  It is not safe to read or modify this variable
5074** if a [database connection] is being used at the same time in a separate
5075** thread.
5076** It is intended that this variable be set once
5077** as part of process initialization and before any SQLite interface
5078** routines have been called and that this variable remain unchanged
5079** thereafter.
5081** ^The [temp_store_directory pragma] may modify this variable and cause
5082** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
5083** the [temp_store_directory pragma] always assumes that any string
5084** that this variable points to is held in memory obtained from
5085** [sqlite3_malloc] and the pragma may attempt to free that memory
5086** using [sqlite3_free].
5087** Hence, if this variable is modified directly, either it should be
5088** made NULL or made to point to memory obtained from [sqlite3_malloc]
5089** or else the use of the [temp_store_directory pragma] should be avoided.
5090** Except when requested by the [temp_store_directory pragma], SQLite
5091** does not free the memory that sqlite3_temp_directory points to.  If
5092** the application wants that memory to be freed, it must do
5093** so itself, taking care to only do so after all [database connection]
5094** objects have been destroyed.
5096** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
5097** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
5098** features that require the use of temporary files may fail.  Here is an
5099** example of how to do this using C++ with the Windows Runtime:
5101** <blockquote><pre>
5102** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
5103** &nbsp;     TemporaryFolder->Path->Data();
5104** char zPathBuf&#91;MAX_PATH + 1&#93;;
5105** memset(zPathBuf, 0, sizeof(zPathBuf));
5106** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
5107** &nbsp;     NULL, NULL);
5108** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
5109** </pre></blockquote>
5111SQLITE_API char *sqlite3_temp_directory;
5114** CAPI3REF: Name Of The Folder Holding Database Files
5116** ^(If this global variable is made to point to a string which is
5117** the name of a folder (a.k.a. directory), then all database files
5118** specified with a relative pathname and created or accessed by
5119** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
5120** to be relative to that directory.)^ ^If this variable is a NULL
5121** pointer, then SQLite assumes that all database files specified
5122** with a relative pathname are relative to the current directory
5123** for the process.  Only the windows VFS makes use of this global
5124** variable; it is ignored by the unix VFS.
5126** Changing the value of this variable while a database connection is
5127** open can result in a corrupt database.
5129** It is not safe to read or modify this variable in more than one
5130** thread at a time.  It is not safe to read or modify this variable
5131** if a [database connection] is being used at the same time in a separate
5132** thread.
5133** It is intended that this variable be set once
5134** as part of process initialization and before any SQLite interface
5135** routines have been called and that this variable remain unchanged
5136** thereafter.
5138** ^The [data_store_directory pragma] may modify this variable and cause
5139** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
5140** the [data_store_directory pragma] always assumes that any string
5141** that this variable points to is held in memory obtained from
5142** [sqlite3_malloc] and the pragma may attempt to free that memory
5143** using [sqlite3_free].
5144** Hence, if this variable is modified directly, either it should be
5145** made NULL or made to point to memory obtained from [sqlite3_malloc]
5146** or else the use of the [data_store_directory pragma] should be avoided.
5148SQLITE_API char *sqlite3_data_directory;
5151** CAPI3REF: Test For Auto-Commit Mode
5152** KEYWORDS: {autocommit mode}
5153** METHOD: sqlite3
5155** ^The sqlite3_get_autocommit() interface returns non-zero or
5156** zero if the given database connection is or is not in autocommit mode,
5157** respectively.  ^Autocommit mode is on by default.
5158** ^Autocommit mode is disabled by a [BEGIN] statement.
5159** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
5161** If certain kinds of errors occur on a statement within a multi-statement
5162** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
5164** transaction might be rolled back automatically.  The only way to
5165** find out whether SQLite automatically rolled back the transaction after
5166** an error is to use this function.
5168** If another thread changes the autocommit status of the database
5169** connection while this routine is running, then the return value
5170** is undefined.
5172SQLITE_API int SQLITE_STDCALL sqlite3_get_autocommit(sqlite3*);
5175** CAPI3REF: Find The Database Handle Of A Prepared Statement
5176** METHOD: sqlite3_stmt
5178** ^The sqlite3_db_handle interface returns the [database connection] handle
5179** to which a [prepared statement] belongs.  ^The [database connection]
5180** returned by sqlite3_db_handle is the same [database connection]
5181** that was the first argument
5182** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
5183** create the statement in the first place.
5185SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_db_handle(sqlite3_stmt*);
5188** CAPI3REF: Return The Filename For A Database Connection
5189** METHOD: sqlite3
5191** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
5192** associated with database N of connection D.  ^The main database file
5193** has the name "main".  If there is no attached database N on the database
5194** connection D, or if database N is a temporary or in-memory database, then
5195** a NULL pointer is returned.
5197** ^The filename returned by this function is the output of the
5198** xFullPathname method of the [VFS].  ^In other words, the filename
5199** will be an absolute pathname, even if the filename used
5200** to open the database originally was a URI or relative pathname.
5202SQLITE_API const char *SQLITE_STDCALL sqlite3_db_filename(sqlite3 *db, const char *zDbName);
5205** CAPI3REF: Determine if a database is read-only
5206** METHOD: sqlite3
5208** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
5209** of connection D is read-only, 0 if it is read/write, or -1 if N is not
5210** the name of a database on connection D.
5212SQLITE_API int SQLITE_STDCALL sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
5215** CAPI3REF: Find the next prepared statement
5216** METHOD: sqlite3
5218** ^This interface returns a pointer to the next [prepared statement] after
5219** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
5220** then this interface returns a pointer to the first prepared statement
5221** associated with the database connection pDb.  ^If no prepared statement
5222** satisfies the conditions of this routine, it returns NULL.
5224** The [database connection] pointer D in a call to
5225** [sqlite3_next_stmt(D,S)] must refer to an open database
5226** connection and in particular must not be a NULL pointer.
5228SQLITE_API sqlite3_stmt *SQLITE_STDCALL sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
5231** CAPI3REF: Commit And Rollback Notification Callbacks
5232** METHOD: sqlite3
5234** ^The sqlite3_commit_hook() interface registers a callback
5235** function to be invoked whenever a transaction is [COMMIT | committed].
5236** ^Any callback set by a previous call to sqlite3_commit_hook()
5237** for the same database connection is overridden.
5238** ^The sqlite3_rollback_hook() interface registers a callback
5239** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
5240** ^Any callback set by a previous call to sqlite3_rollback_hook()
5241** for the same database connection is overridden.
5242** ^The pArg argument is passed through to the callback.
5243** ^If the callback on a commit hook function returns non-zero,
5244** then the commit is converted into a rollback.
5246** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
5247** return the P argument from the previous call of the same function
5248** on the same [database connection] D, or NULL for
5249** the first call for each function on D.
5251** The commit and rollback hook callbacks are not reentrant.
5252** The callback implementation must not do anything that will modify
5253** the database connection that invoked the callback.  Any actions
5254** to modify the database connection must be deferred until after the
5255** completion of the [sqlite3_step()] call that triggered the commit
5256** or rollback hook in the first place.
5257** Note that running any other SQL statements, including SELECT statements,
5258** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
5259** the database connections for the meaning of "modify" in this paragraph.
5261** ^Registering a NULL function disables the callback.
5263** ^When the commit hook callback routine returns zero, the [COMMIT]
5264** operation is allowed to continue normally.  ^If the commit hook
5265** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
5266** ^The rollback hook is invoked on a rollback that results from a commit
5267** hook returning non-zero, just as it would be with any other rollback.
5269** ^For the purposes of this API, a transaction is said to have been
5270** rolled back if an explicit "ROLLBACK" statement is executed, or
5271** an error or constraint causes an implicit rollback to occur.
5272** ^The rollback callback is not invoked if a transaction is
5273** automatically rolled back because the database connection is closed.
5275** See also the [sqlite3_update_hook()] interface.
5277SQLITE_API void *SQLITE_STDCALL sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
5278SQLITE_API void *SQLITE_STDCALL sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
5281** CAPI3REF: Data Change Notification Callbacks
5282** METHOD: sqlite3
5284** ^The sqlite3_update_hook() interface registers a callback function
5285** with the [database connection] identified by the first argument
5286** to be invoked whenever a row is updated, inserted or deleted in
5287** a rowid table.
5288** ^Any callback set by a previous call to this function
5289** for the same database connection is overridden.
5291** ^The second argument is a pointer to the function to invoke when a
5292** row is updated, inserted or deleted in a rowid table.
5293** ^The first argument to the callback is a copy of the third argument
5294** to sqlite3_update_hook().
5295** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
5296** or [SQLITE_UPDATE], depending on the operation that caused the callback
5297** to be invoked.
5298** ^The third and fourth arguments to the callback contain pointers to the
5299** database and table name containing the affected row.
5300** ^The final callback parameter is the [rowid] of the row.
5301** ^In the case of an update, this is the [rowid] after the update takes place.
5303** ^(The update hook is not invoked when internal system tables are
5304** modified (i.e. sqlite_master and sqlite_sequence).)^
5305** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
5307** ^In the current implementation, the update hook
5308** is not invoked when duplication rows are deleted because of an
5309** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
5310** invoked when rows are deleted using the [truncate optimization].
5311** The exceptions defined in this paragraph might change in a future
5312** release of SQLite.
5314** The update hook implementation must not do anything that will modify
5315** the database connection that invoked the update hook.  Any actions
5316** to modify the database connection must be deferred until after the
5317** completion of the [sqlite3_step()] call that triggered the update hook.
5318** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
5319** database connections for the meaning of "modify" in this paragraph.
5321** ^The sqlite3_update_hook(D,C,P) function
5322** returns the P argument from the previous call
5323** on the same [database connection] D, or NULL for
5324** the first call on D.
5326** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
5327** interfaces.
5329SQLITE_API void *SQLITE_STDCALL sqlite3_update_hook(
5330  sqlite3*,
5331  void(*)(void *,int ,char const *,char const *,sqlite3_int64),
5332  void*
5336** CAPI3REF: Enable Or Disable Shared Pager Cache
5338** ^(This routine enables or disables the sharing of the database cache
5339** and schema data structures between [database connection | connections]
5340** to the same database. Sharing is enabled if the argument is true
5341** and disabled if the argument is false.)^
5343** ^Cache sharing is enabled and disabled for an entire process.
5344** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
5345** sharing was enabled or disabled for each thread separately.
5347** ^(The cache sharing mode set by this interface effects all subsequent
5348** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
5349** Existing database connections continue use the sharing mode
5350** that was in effect at the time they were opened.)^
5352** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
5353** successfully.  An [error code] is returned otherwise.)^
5355** ^Shared cache is disabled by default. But this might change in
5356** future releases of SQLite.  Applications that care about shared
5357** cache setting should set it explicitly.
5359** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
5360** and will always return SQLITE_MISUSE. On those systems,
5361** shared cache mode should be enabled per-database connection via
5362** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
5364** This interface is threadsafe on processors where writing a
5365** 32-bit integer is atomic.
5367** See Also:  [SQLite Shared-Cache Mode]
5369SQLITE_API int SQLITE_STDCALL sqlite3_enable_shared_cache(int);
5372** CAPI3REF: Attempt To Free Heap Memory
5374** ^The sqlite3_release_memory() interface attempts to free N bytes
5375** of heap memory by deallocating non-essential memory allocations
5376** held by the database library.   Memory used to cache database
5377** pages to improve performance is an example of non-essential memory.
5378** ^sqlite3_release_memory() returns the number of bytes actually freed,
5379** which might be more or less than the amount requested.
5380** ^The sqlite3_release_memory() routine is a no-op returning zero
5381** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5383** See also: [sqlite3_db_release_memory()]
5385SQLITE_API int SQLITE_STDCALL sqlite3_release_memory(int);
5388** CAPI3REF: Free Memory Used By A Database Connection
5389** METHOD: sqlite3
5391** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
5392** memory as possible from database connection D. Unlike the
5393** [sqlite3_release_memory()] interface, this interface is in effect even
5394** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
5395** omitted.
5397** See also: [sqlite3_release_memory()]
5399SQLITE_API int SQLITE_STDCALL sqlite3_db_release_memory(sqlite3*);
5402** CAPI3REF: Impose A Limit On Heap Size
5404** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
5405** soft limit on the amount of heap memory that may be allocated by SQLite.
5406** ^SQLite strives to keep heap memory utilization below the soft heap
5407** limit by reducing the number of pages held in the page cache
5408** as heap memory usages approaches the limit.
5409** ^The soft heap limit is "soft" because even though SQLite strives to stay
5410** below the limit, it will exceed the limit rather than generate
5411** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
5412** is advisory only.
5414** ^The return value from sqlite3_soft_heap_limit64() is the size of
5415** the soft heap limit prior to the call, or negative in the case of an
5416** error.  ^If the argument N is negative
5417** then no change is made to the soft heap limit.  Hence, the current
5418** size of the soft heap limit can be determined by invoking
5419** sqlite3_soft_heap_limit64() with a negative argument.
5421** ^If the argument N is zero then the soft heap limit is disabled.
5423** ^(The soft heap limit is not enforced in the current implementation
5424** if one or more of following conditions are true:
5426** <ul>
5427** <li> The soft heap limit is set to zero.
5428** <li> Memory accounting is disabled using a combination of the
5429**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
5430**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
5431** <li> An alternative page cache implementation is specified using
5432**      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
5433** <li> The page cache allocates from its own memory pool supplied
5434**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
5435**      from the heap.
5436** </ul>)^
5438** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
5439** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
5440** compile-time option is invoked.  With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
5441** the soft heap limit is enforced on every memory allocation.  Without
5442** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
5443** when memory is allocated by the page cache.  Testing suggests that because
5444** the page cache is the predominate memory user in SQLite, most
5445** applications will achieve adequate soft heap limit enforcement without
5448** The circumstances under which SQLite will enforce the soft heap limit may
5449** changes in future releases of SQLite.
5451SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_soft_heap_limit64(sqlite3_int64 N);
5454** CAPI3REF: Deprecated Soft Heap Limit Interface
5457** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
5458** interface.  This routine is provided for historical compatibility
5459** only.  All new applications should use the
5460** [sqlite3_soft_heap_limit64()] interface rather than this one.
5462SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_soft_heap_limit(int N);
5466** CAPI3REF: Extract Metadata About A Column Of A Table
5467** METHOD: sqlite3
5469** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
5470** information about column C of table T in database D
5471** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
5472** interface returns SQLITE_OK and fills in the non-NULL pointers in
5473** the final five arguments with appropriate values if the specified
5474** column exists.  ^The sqlite3_table_column_metadata() interface returns
5475** SQLITE_ERROR and if the specified column does not exist.
5476** ^If the column-name parameter to sqlite3_table_column_metadata() is a
5477** NULL pointer, then this routine simply checks for the existance of the
5478** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
5479** does not.
5481** ^The column is identified by the second, third and fourth parameters to
5482** this function. ^(The second parameter is either the name of the database
5483** (i.e. "main", "temp", or an attached database) containing the specified
5484** table or NULL.)^ ^If it is NULL, then all attached databases are searched
5485** for the table using the same algorithm used by the database engine to
5486** resolve unqualified table references.
5488** ^The third and fourth parameters to this function are the table and column
5489** name of the desired column, respectively.
5491** ^Metadata is returned by writing to the memory locations passed as the 5th
5492** and subsequent parameters to this function. ^Any of these arguments may be
5493** NULL, in which case the corresponding element of metadata is omitted.
5495** ^(<blockquote>
5496** <table border="1">
5497** <tr><th> Parameter <th> Output<br>Type <th>  Description
5499** <tr><td> 5th <td> const char* <td> Data type
5500** <tr><td> 6th <td> const char* <td> Name of default collation sequence
5501** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
5502** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
5503** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
5504** </table>
5505** </blockquote>)^
5507** ^The memory pointed to by the character pointers returned for the
5508** declaration type and collation sequence is valid until the next
5509** call to any SQLite API function.
5511** ^If the specified table is actually a view, an [error code] is returned.
5513** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
5514** is not a [WITHOUT ROWID] table and an
5515** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
5516** parameters are set for the explicitly declared column. ^(If there is no
5517** [INTEGER PRIMARY KEY] column, then the outputs
5518** for the [rowid] are set as follows:
5520** <pre>
5521**     data type: "INTEGER"
5522**     collation sequence: "BINARY"
5523**     not null: 0
5524**     primary key: 1
5525**     auto increment: 0
5526** </pre>)^
5528** ^This function causes all database schemas to be read from disk and
5529** parsed, if that has not already been done, and returns an error if
5530** any errors are encountered while loading the schema.
5532SQLITE_API int SQLITE_STDCALL sqlite3_table_column_metadata(
5533  sqlite3 *db,                /* Connection handle */
5534  const char *zDbName,        /* Database name or NULL */
5535  const char *zTableName,     /* Table name */
5536  const char *zColumnName,    /* Column name */
5537  char const **pzDataType,    /* OUTPUT: Declared data type */
5538  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
5539  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
5540  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
5541  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
5545** CAPI3REF: Load An Extension
5546** METHOD: sqlite3
5548** ^This interface loads an SQLite extension library from the named file.
5550** ^The sqlite3_load_extension() interface attempts to load an
5551** [SQLite extension] library contained in the file zFile.  If
5552** the file cannot be loaded directly, attempts are made to load
5553** with various operating-system specific extensions added.
5554** So for example, if "samplelib" cannot be loaded, then names like
5555** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
5556** be tried also.
5558** ^The entry point is zProc.
5559** ^(zProc may be 0, in which case SQLite will try to come up with an
5560** entry point name on its own.  It first tries "sqlite3_extension_init".
5561** If that does not work, it constructs a name "sqlite3_X_init" where the
5562** X is consists of the lower-case equivalent of all ASCII alphabetic
5563** characters in the filename from the last "/" to the first following
5564** "." and omitting any initial "lib".)^
5565** ^The sqlite3_load_extension() interface returns
5566** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
5567** ^If an error occurs and pzErrMsg is not 0, then the
5568** [sqlite3_load_extension()] interface shall attempt to
5569** fill *pzErrMsg with error message text stored in memory
5570** obtained from [sqlite3_malloc()]. The calling function
5571** should free this memory by calling [sqlite3_free()].
5573** ^Extension loading must be enabled using
5574** [sqlite3_enable_load_extension()] prior to calling this API,
5575** otherwise an error will be returned.
5577** See also the [load_extension() SQL function].
5579SQLITE_API int SQLITE_STDCALL sqlite3_load_extension(
5580  sqlite3 *db,          /* Load the extension into this database connection */
5581  const char *zFile,    /* Name of the shared library containing extension */
5582  const char *zProc,    /* Entry point.  Derived from zFile if 0 */
5583  char **pzErrMsg       /* Put error message here if not 0 */
5587** CAPI3REF: Enable Or Disable Extension Loading
5588** METHOD: sqlite3
5590** ^So as not to open security holes in older applications that are
5591** unprepared to deal with [extension loading], and as a means of disabling
5592** [extension loading] while evaluating user-entered SQL, the following API
5593** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5595** ^Extension loading is off by default.
5596** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5597** to turn extension loading on and call it with onoff==0 to turn
5598** it back off again.
5600SQLITE_API int SQLITE_STDCALL sqlite3_enable_load_extension(sqlite3 *db, int onoff);
5603** CAPI3REF: Automatically Load Statically Linked Extensions
5605** ^This interface causes the xEntryPoint() function to be invoked for
5606** each new [database connection] that is created.  The idea here is that
5607** xEntryPoint() is the entry point for a statically linked [SQLite extension]
5608** that is to be automatically loaded into all new database connections.
5610** ^(Even though the function prototype shows that xEntryPoint() takes
5611** no arguments and returns void, SQLite invokes xEntryPoint() with three
5612** arguments and expects and integer result as if the signature of the
5613** entry point where as follows:
5615** <blockquote><pre>
5616** &nbsp;  int xEntryPoint(
5617** &nbsp;    sqlite3 *db,
5618** &nbsp;    const char **pzErrMsg,
5619** &nbsp;    const struct sqlite3_api_routines *pThunk
5620** &nbsp;  );
5621** </pre></blockquote>)^
5623** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
5624** point to an appropriate error message (obtained from [sqlite3_mprintf()])
5625** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
5626** is NULL before calling the xEntryPoint().  ^SQLite will invoke
5627** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
5628** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
5629** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
5631** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
5632** on the list of automatic extensions is a harmless no-op. ^No entry point
5633** will be called more than once for each database connection that is opened.
5635** See also: [sqlite3_reset_auto_extension()]
5636** and [sqlite3_cancel_auto_extension()]
5638SQLITE_API int SQLITE_STDCALL sqlite3_auto_extension(void (*xEntryPoint)(void));
5641** CAPI3REF: Cancel Automatic Extension Loading
5643** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
5644** initialization routine X that was registered using a prior call to
5645** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
5646** routine returns 1 if initialization routine X was successfully
5647** unregistered and it returns 0 if X was not on the list of initialization
5648** routines.
5650SQLITE_API int SQLITE_STDCALL sqlite3_cancel_auto_extension(void (*xEntryPoint)(void));
5653** CAPI3REF: Reset Automatic Extension Loading
5655** ^This interface disables all automatic extensions previously
5656** registered using [sqlite3_auto_extension()].
5658SQLITE_API void SQLITE_STDCALL sqlite3_reset_auto_extension(void);
5661** The interface to the virtual-table mechanism is currently considered
5662** to be experimental.  The interface might change in incompatible ways.
5663** If this is a problem for you, do not use the interface at this time.
5665** When the virtual-table mechanism stabilizes, we will declare the
5666** interface fixed, support it indefinitely, and remove this comment.
5670** Structures used by the virtual table interface
5672typedef struct sqlite3_vtab sqlite3_vtab;
5673typedef struct sqlite3_index_info sqlite3_index_info;
5674typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
5675typedef struct sqlite3_module sqlite3_module;
5678** CAPI3REF: Virtual Table Object
5679** KEYWORDS: sqlite3_module {virtual table module}
5681** This structure, sometimes called a "virtual table module",
5682** defines the implementation of a [virtual tables].
5683** This structure consists mostly of methods for the module.
5685** ^A virtual table module is created by filling in a persistent
5686** instance of this structure and passing a pointer to that instance
5687** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
5688** ^The registration remains valid until it is replaced by a different
5689** module or until the [database connection] closes.  The content
5690** of this structure must not change while it is registered with
5691** any database connection.
5693struct sqlite3_module {
5694  int iVersion;
5695  int (*xCreate)(sqlite3*, void *pAux,
5696               int argc, const char *const*argv,
5697               sqlite3_vtab **ppVTab, char**);
5698  int (*xConnect)(sqlite3*, void *pAux,
5699               int argc, const char *const*argv,
5700               sqlite3_vtab **ppVTab, char**);
5701  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
5702  int (*xDisconnect)(sqlite3_vtab *pVTab);
5703  int (*xDestroy)(sqlite3_vtab *pVTab);
5704  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
5705  int (*xClose)(sqlite3_vtab_cursor*);
5706  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
5707                int argc, sqlite3_value **argv);
5708  int (*xNext)(sqlite3_vtab_cursor*);
5709  int (*xEof)(sqlite3_vtab_cursor*);
5710  int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
5711  int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
5712  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
5713  int (*xBegin)(sqlite3_vtab *pVTab);
5714  int (*xSync)(sqlite3_vtab *pVTab);
5715  int (*xCommit)(sqlite3_vtab *pVTab);
5716  int (*xRollback)(sqlite3_vtab *pVTab);
5717  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
5718                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
5719                       void **ppArg);
5720  int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
5721  /* The methods above are in version 1 of the sqlite_module object. Those
5722  ** below are for version 2 and greater. */
5723  int (*xSavepoint)(sqlite3_vtab *pVTab, int);
5724  int (*xRelease)(sqlite3_vtab *pVTab, int);
5725  int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
5729** CAPI3REF: Virtual Table Indexing Information
5730** KEYWORDS: sqlite3_index_info
5732** The sqlite3_index_info structure and its substructures is used as part
5733** of the [virtual table] interface to
5734** pass information into and receive the reply from the [xBestIndex]
5735** method of a [virtual table module].  The fields under **Inputs** are the
5736** inputs to xBestIndex and are read-only.  xBestIndex inserts its
5737** results into the **Outputs** fields.
5739** ^(The aConstraint[] array records WHERE clause constraints of the form:
5741** <blockquote>column OP expr</blockquote>
5743** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
5744** stored in aConstraint[].op using one of the
5746** ^(The index of the column is stored in
5747** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
5748** expr on the right-hand side can be evaluated (and thus the constraint
5749** is usable) and false if it cannot.)^
5751** ^The optimizer automatically inverts terms of the form "expr OP column"
5752** and makes other simplifications to the WHERE clause in an attempt to
5753** get as many WHERE clause terms into the form shown above as possible.
5754** ^The aConstraint[] array only reports WHERE clause terms that are
5755** relevant to the particular virtual table being queried.
5757** ^Information about the ORDER BY clause is stored in aOrderBy[].
5758** ^Each term of aOrderBy records a column of the ORDER BY clause.
5760** The [xBestIndex] method must fill aConstraintUsage[] with information
5761** about what parameters to pass to xFilter.  ^If argvIndex>0 then
5762** the right-hand side of the corresponding aConstraint[] is evaluated
5763** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
5764** is true, then the constraint is assumed to be fully handled by the
5765** virtual table and is not checked again by SQLite.)^
5767** ^The idxNum and idxPtr values are recorded and passed into the
5768** [xFilter] method.
5769** ^[sqlite3_free()] is used to free idxPtr if and only if
5770** needToFreeIdxPtr is true.
5772** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
5773** the correct order to satisfy the ORDER BY clause so that no separate
5774** sorting step is required.
5776** ^The estimatedCost value is an estimate of the cost of a particular
5777** strategy. A cost of N indicates that the cost of the strategy is similar
5778** to a linear scan of an SQLite table with N rows. A cost of log(N)
5779** indicates that the expense of the operation is similar to that of a
5780** binary search on a unique indexed field of an SQLite table with N rows.
5782** ^The estimatedRows value is an estimate of the number of rows that
5783** will be returned by the strategy.
5785** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
5786** structure for SQLite version 3.8.2. If a virtual table extension is
5787** used with an SQLite version earlier than 3.8.2, the results of attempting
5788** to read or write the estimatedRows field are undefined (but are likely
5789** to included crashing the application). The estimatedRows field should
5790** therefore only be used if [sqlite3_libversion_number()] returns a
5791** value greater than or equal to 3008002.
5793struct sqlite3_index_info {
5794  /* Inputs */
5795  int nConstraint;           /* Number of entries in aConstraint */
5796  struct sqlite3_index_constraint {
5797     int iColumn;              /* Column on left-hand side of constraint */
5798     unsigned char op;         /* Constraint operator */
5799     unsigned char usable;     /* True if this constraint is usable */
5800     int iTermOffset;          /* Used internally - xBestIndex should ignore */
5801  } *aConstraint;            /* Table of WHERE clause constraints */
5802  int nOrderBy;              /* Number of terms in the ORDER BY clause */
5803  struct sqlite3_index_orderby {
5804     int iColumn;              /* Column number */
5805     unsigned char desc;       /* True for DESC.  False for ASC. */
5806  } *aOrderBy;               /* The ORDER BY clause */
5807  /* Outputs */
5808  struct sqlite3_index_constraint_usage {
5809    int argvIndex;           /* if >0, constraint is part of argv to xFilter */
5810    unsigned char omit;      /* Do not code a test for this constraint */
5811  } *aConstraintUsage;
5812  int idxNum;                /* Number used to identify the index */
5813  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
5814  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
5815  int orderByConsumed;       /* True if output is already ordered */
5816  double estimatedCost;           /* Estimated cost of using this index */
5817  /* Fields below are only available in SQLite 3.8.2 and later */
5818  sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
5822** CAPI3REF: Virtual Table Constraint Operator Codes
5824** These macros defined the allowed values for the
5825** [sqlite3_index_info].aConstraint[].op field.  Each value represents
5826** an operator that is part of a constraint term in the wHERE clause of
5827** a query that uses a [virtual table].
5837** CAPI3REF: Register A Virtual Table Implementation
5838** METHOD: sqlite3
5840** ^These routines are used to register a new [virtual table module] name.
5841** ^Module names must be registered before
5842** creating a new [virtual table] using the module and before using a
5843** preexisting [virtual table] for the module.
5845** ^The module name is registered on the [database connection] specified
5846** by the first parameter.  ^The name of the module is given by the
5847** second parameter.  ^The third parameter is a pointer to
5848** the implementation of the [virtual table module].   ^The fourth
5849** parameter is an arbitrary client data pointer that is passed through
5850** into the [xCreate] and [xConnect] methods of the virtual table module
5851** when a new virtual table is be being created or reinitialized.
5853** ^The sqlite3_create_module_v2() interface has a fifth parameter which
5854** is a pointer to a destructor for the pClientData.  ^SQLite will
5855** invoke the destructor function (if it is not NULL) when SQLite
5856** no longer needs the pClientData pointer.  ^The destructor will also
5857** be invoked if the call to sqlite3_create_module_v2() fails.
5858** ^The sqlite3_create_module()
5859** interface is equivalent to sqlite3_create_module_v2() with a NULL
5860** destructor.
5862SQLITE_API int SQLITE_STDCALL sqlite3_create_module(
5863  sqlite3 *db,               /* SQLite connection to register module with */
5864  const char *zName,         /* Name of the module */
5865  const sqlite3_module *p,   /* Methods for the module */
5866  void *pClientData          /* Client data for xCreate/xConnect */
5868SQLITE_API int SQLITE_STDCALL sqlite3_create_module_v2(
5869  sqlite3 *db,               /* SQLite connection to register module with */
5870  const char *zName,         /* Name of the module */
5871  const sqlite3_module *p,   /* Methods for the module */
5872  void *pClientData,         /* Client data for xCreate/xConnect */
5873  void(*xDestroy)(void*)     /* Module destructor function */
5877** CAPI3REF: Virtual Table Instance Object
5878** KEYWORDS: sqlite3_vtab
5880** Every [virtual table module] implementation uses a subclass
5881** of this object to describe a particular instance
5882** of the [virtual table].  Each subclass will
5883** be tailored to the specific needs of the module implementation.
5884** The purpose of this superclass is to define certain fields that are
5885** common to all module implementations.
5887** ^Virtual tables methods can set an error message by assigning a
5888** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
5889** take care that any prior string is freed by a call to [sqlite3_free()]
5890** prior to assigning a new string to zErrMsg.  ^After the error message
5891** is delivered up to the client application, the string will be automatically
5892** freed by sqlite3_free() and the zErrMsg field will be zeroed.
5894struct sqlite3_vtab {
5895  const sqlite3_module *pModule;  /* The module for this virtual table */
5896  int nRef;                       /* Number of open cursors */
5897  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
5898  /* Virtual table implementations will typically add additional fields */
5902** CAPI3REF: Virtual Table Cursor Object
5903** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
5905** Every [virtual table module] implementation uses a subclass of the
5906** following structure to describe cursors that point into the
5907** [virtual table] and are used
5908** to loop through the virtual table.  Cursors are created using the
5909** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
5910** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
5911** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
5912** of the module.  Each module implementation will define
5913** the content of a cursor structure to suit its own needs.
5915** This superclass exists in order to define fields of the cursor that
5916** are common to all implementations.
5918struct sqlite3_vtab_cursor {
5919  sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
5920  /* Virtual table implementations will typically add additional fields */
5924** CAPI3REF: Declare The Schema Of A Virtual Table
5926** ^The [xCreate] and [xConnect] methods of a
5927** [virtual table module] call this interface
5928** to declare the format (the names and datatypes of the columns) of
5929** the virtual tables they implement.
5931SQLITE_API int SQLITE_STDCALL sqlite3_declare_vtab(sqlite3*, const char *zSQL);
5934** CAPI3REF: Overload A Function For A Virtual Table
5935** METHOD: sqlite3
5937** ^(Virtual tables can provide alternative implementations of functions
5938** using the [xFindFunction] method of the [virtual table module].
5939** But global versions of those functions
5940** must exist in order to be overloaded.)^
5942** ^(This API makes sure a global version of a function with a particular
5943** name and number of parameters exists.  If no such function exists
5944** before this API is called, a new function is created.)^  ^The implementation
5945** of the new function always causes an exception to be thrown.  So
5946** the new function is not good for anything by itself.  Its only
5947** purpose is to be a placeholder function that can be overloaded
5948** by a [virtual table].
5950SQLITE_API int SQLITE_STDCALL sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
5953** The interface to the virtual-table mechanism defined above (back up
5954** to a comment remarkably similar to this one) is currently considered
5955** to be experimental.  The interface might change in incompatible ways.
5956** If this is a problem for you, do not use the interface at this time.
5958** When the virtual-table mechanism stabilizes, we will declare the
5959** interface fixed, support it indefinitely, and remove this comment.
5963** CAPI3REF: A Handle To An Open BLOB
5964** KEYWORDS: {BLOB handle} {BLOB handles}
5966** An instance of this object represents an open BLOB on which
5967** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
5968** ^Objects of this type are created by [sqlite3_blob_open()]
5969** and destroyed by [sqlite3_blob_close()].
5970** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
5971** can be used to read or write small subsections of the BLOB.
5972** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
5974typedef struct sqlite3_blob sqlite3_blob;
5977** CAPI3REF: Open A BLOB For Incremental I/O
5978** METHOD: sqlite3
5979** CONSTRUCTOR: sqlite3_blob
5981** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
5982** in row iRow, column zColumn, table zTable in database zDb;
5983** in other words, the same BLOB that would be selected by:
5985** <pre>
5986**     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
5987** </pre>)^
5989** ^(Parameter zDb is not the filename that contains the database, but
5990** rather the symbolic name of the database. For attached databases, this is
5991** the name that appears after the AS keyword in the [ATTACH] statement.
5992** For the main database file, the database name is "main". For TEMP
5993** tables, the database name is "temp".)^
5995** ^If the flags parameter is non-zero, then the BLOB is opened for read
5996** and write access. ^If the flags parameter is zero, the BLOB is opened for
5997** read-only access.
5999** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
6000** in *ppBlob. Otherwise an [error code] is returned and, unless the error
6001** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
6002** the API is not misused, it is always safe to call [sqlite3_blob_close()]
6003** on *ppBlob after this function it returns.
6005** This function fails with SQLITE_ERROR if any of the following are true:
6006** <ul>
6007**   <li> ^(Database zDb does not exist)^,
6008**   <li> ^(Table zTable does not exist within database zDb)^,
6009**   <li> ^(Table zTable is a WITHOUT ROWID table)^,
6010**   <li> ^(Column zColumn does not exist)^,
6011**   <li> ^(Row iRow is not present in the table)^,
6012**   <li> ^(The specified column of row iRow contains a value that is not
6013**         a TEXT or BLOB value)^,
6014**   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
6015**         constraint and the blob is being opened for read/write access)^,
6016**   <li> ^([foreign key constraints | Foreign key constraints] are enabled,
6017**         column zColumn is part of a [child key] definition and the blob is
6018**         being opened for read/write access)^.
6019** </ul>
6021** ^Unless it returns SQLITE_MISUSE, this function sets the
6022** [database connection] error code and message accessible via
6023** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6026** ^(If the row that a BLOB handle points to is modified by an
6027** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
6028** then the BLOB handle is marked as "expired".
6029** This is true if any column of the row is changed, even a column
6030** other than the one the BLOB handle is open on.)^
6031** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
6032** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
6033** ^(Changes written into a BLOB prior to the BLOB expiring are not
6034** rolled back by the expiration of the BLOB.  Such changes will eventually
6035** commit if the transaction continues to completion.)^
6037** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
6038** the opened blob.  ^The size of a blob may not be changed by this
6039** interface.  Use the [UPDATE] SQL command to change the size of a
6040** blob.
6042** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
6043** and the built-in [zeroblob] SQL function may be used to create a
6044** zero-filled blob to read or write using the incremental-blob interface.
6046** To avoid a resource leak, every open [BLOB handle] should eventually
6047** be released by a call to [sqlite3_blob_close()].
6049SQLITE_API int SQLITE_STDCALL sqlite3_blob_open(
6050  sqlite3*,
6051  const char *zDb,
6052  const char *zTable,
6053  const char *zColumn,
6054  sqlite3_int64 iRow,
6055  int flags,
6056  sqlite3_blob **ppBlob
6060** CAPI3REF: Move a BLOB Handle to a New Row
6061** METHOD: sqlite3_blob
6063** ^This function is used to move an existing blob handle so that it points
6064** to a different row of the same database table. ^The new row is identified
6065** by the rowid value passed as the second argument. Only the row can be
6066** changed. ^The database, table and column on which the blob handle is open
6067** remain the same. Moving an existing blob handle to a new row can be
6068** faster than closing the existing handle and opening a new one.
6070** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
6071** it must exist and there must be either a blob or text value stored in
6072** the nominated column.)^ ^If the new row is not present in the table, or if
6073** it does not contain a blob or text value, or if another error occurs, an
6074** SQLite error code is returned and the blob handle is considered aborted.
6075** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
6076** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
6077** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
6078** always returns zero.
6080** ^This function sets the database handle error code and message.
6082SQLITE_API SQLITE_EXPERIMENTAL int SQLITE_STDCALL sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
6085** CAPI3REF: Close A BLOB Handle
6086** DESTRUCTOR: sqlite3_blob
6088** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
6089** unconditionally.  Even if this routine returns an error code, the
6090** handle is still closed.)^
6092** ^If the blob handle being closed was opened for read-write access, and if
6093** the database is in auto-commit mode and there are no other open read-write
6094** blob handles or active write statements, the current transaction is
6095** committed. ^If an error occurs while committing the transaction, an error
6096** code is returned and the transaction rolled back.
6098** Calling this function with an argument that is not a NULL pointer or an
6099** open blob handle results in undefined behaviour. ^Calling this routine
6100** with a null pointer (such as would be returned by a failed call to
6101** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
6102** is passed a valid open blob handle, the values returned by the
6103** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
6105SQLITE_API int SQLITE_STDCALL sqlite3_blob_close(sqlite3_blob *);
6108** CAPI3REF: Return The Size Of An Open BLOB
6109** METHOD: sqlite3_blob
6111** ^Returns the size in bytes of the BLOB accessible via the
6112** successfully opened [BLOB handle] in its only argument.  ^The
6113** incremental blob I/O routines can only read or overwriting existing
6114** blob content; they cannot change the size of a blob.
6116** This routine only works on a [BLOB handle] which has been created
6117** by a prior successful call to [sqlite3_blob_open()] and which has not
6118** been closed by [sqlite3_blob_close()].  Passing any other pointer in
6119** to this routine results in undefined and probably undesirable behavior.
6121SQLITE_API int SQLITE_STDCALL sqlite3_blob_bytes(sqlite3_blob *);
6124** CAPI3REF: Read Data From A BLOB Incrementally
6125** METHOD: sqlite3_blob
6127** ^(This function is used to read data from an open [BLOB handle] into a
6128** caller-supplied buffer. N bytes of data are copied into buffer Z
6129** from the open BLOB, starting at offset iOffset.)^
6131** ^If offset iOffset is less than N bytes from the end of the BLOB,
6132** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
6133** less than zero, [SQLITE_ERROR] is returned and no data is read.
6134** ^The size of the blob (and hence the maximum value of N+iOffset)
6135** can be determined using the [sqlite3_blob_bytes()] interface.
6137** ^An attempt to read from an expired [BLOB handle] fails with an
6138** error code of [SQLITE_ABORT].
6140** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
6141** Otherwise, an [error code] or an [extended error code] is returned.)^
6143** This routine only works on a [BLOB handle] which has been created
6144** by a prior successful call to [sqlite3_blob_open()] and which has not
6145** been closed by [sqlite3_blob_close()].  Passing any other pointer in
6146** to this routine results in undefined and probably undesirable behavior.
6148** See also: [sqlite3_blob_write()].
6150SQLITE_API int SQLITE_STDCALL sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
6153** CAPI3REF: Write Data Into A BLOB Incrementally
6154** METHOD: sqlite3_blob
6156** ^(This function is used to write data into an open [BLOB handle] from a
6157** caller-supplied buffer. N bytes of data are copied from the buffer Z
6158** into the open BLOB, starting at offset iOffset.)^
6160** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
6161** Otherwise, an  [error code] or an [extended error code] is returned.)^
6162** ^Unless SQLITE_MISUSE is returned, this function sets the
6163** [database connection] error code and message accessible via
6164** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6166** ^If the [BLOB handle] passed as the first argument was not opened for
6167** writing (the flags parameter to [sqlite3_blob_open()] was zero),
6168** this function returns [SQLITE_READONLY].
6170** This function may only modify the contents of the BLOB; it is
6171** not possible to increase the size of a BLOB using this API.
6172** ^If offset iOffset is less than N bytes from the end of the BLOB,
6173** [SQLITE_ERROR] is returned and no data is written. The size of the
6174** BLOB (and hence the maximum value of N+iOffset) can be determined
6175** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
6176** than zero [SQLITE_ERROR] is returned and no data is written.
6178** ^An attempt to write to an expired [BLOB handle] fails with an
6179** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
6180** before the [BLOB handle] expired are not rolled back by the
6181** expiration of the handle, though of course those changes might
6182** have been overwritten by the statement that expired the BLOB handle
6183** or by other independent statements.
6185** This routine only works on a [BLOB handle] which has been created
6186** by a prior successful call to [sqlite3_blob_open()] and which has not
6187** been closed by [sqlite3_blob_close()].  Passing any other pointer in
6188** to this routine results in undefined and probably undesirable behavior.
6190** See also: [sqlite3_blob_read()].
6192SQLITE_API int SQLITE_STDCALL sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
6195** CAPI3REF: Virtual File System Objects
6197** A virtual filesystem (VFS) is an [sqlite3_vfs] object
6198** that SQLite uses to interact
6199** with the underlying operating system.  Most SQLite builds come with a
6200** single default VFS that is appropriate for the host computer.
6201** New VFSes can be registered and existing VFSes can be unregistered.
6202** The following interfaces are provided.
6204** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
6205** ^Names are case sensitive.
6206** ^Names are zero-terminated UTF-8 strings.
6207** ^If there is no match, a NULL pointer is returned.
6208** ^If zVfsName is NULL then the default VFS is returned.
6210** ^New VFSes are registered with sqlite3_vfs_register().
6211** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
6212** ^The same VFS can be registered multiple times without injury.
6213** ^To make an existing VFS into the default VFS, register it again
6214** with the makeDflt flag set.  If two different VFSes with the
6215** same name are registered, the behavior is undefined.  If a
6216** VFS is registered with a name that is NULL or an empty string,
6217** then the behavior is undefined.
6219** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
6220** ^(If the default VFS is unregistered, another VFS is chosen as
6221** the default.  The choice for the new VFS is arbitrary.)^
6223SQLITE_API sqlite3_vfs *SQLITE_STDCALL sqlite3_vfs_find(const char *zVfsName);
6224SQLITE_API int SQLITE_STDCALL sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
6225SQLITE_API int SQLITE_STDCALL sqlite3_vfs_unregister(sqlite3_vfs*);
6228** CAPI3REF: Mutexes
6230** The SQLite core uses these routines for thread
6231** synchronization. Though they are intended for internal
6232** use by SQLite, code that links against SQLite is
6233** permitted to use any of these routines.
6235** The SQLite source code contains multiple implementations
6236** of these mutex routines.  An appropriate implementation
6237** is selected automatically at compile-time.  The following
6238** implementations are available in the SQLite core:
6240** <ul>
6242** <li>   SQLITE_MUTEX_W32
6243** <li>   SQLITE_MUTEX_NOOP
6244** </ul>
6246** The SQLITE_MUTEX_NOOP implementation is a set of routines
6247** that does no real locking and is appropriate for use in
6248** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
6249** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
6250** and Windows.
6252** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
6253** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
6254** implementation is included with the library. In this case the
6255** application must supply a custom mutex implementation using the
6256** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
6257** before calling sqlite3_initialize() or any other public sqlite3_
6258** function that calls sqlite3_initialize().
6260** ^The sqlite3_mutex_alloc() routine allocates a new
6261** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
6262** routine returns NULL if it is unable to allocate the requested
6263** mutex.  The argument to sqlite3_mutex_alloc() must one of these
6264** integer constants:
6266** <ul>
6267** <li>  SQLITE_MUTEX_FAST
6278** </ul>
6280** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
6281** cause sqlite3_mutex_alloc() to create
6282** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
6283** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
6284** The mutex implementation does not need to make a distinction
6285** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
6286** not want to.  SQLite will only request a recursive mutex in
6287** cases where it really needs one.  If a faster non-recursive mutex
6288** implementation is available on the host platform, the mutex subsystem
6289** might return such a mutex in response to SQLITE_MUTEX_FAST.
6291** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
6293** a pointer to a static preexisting mutex.  ^Nine static mutexes are
6294** used by the current version of SQLite.  Future versions of SQLite
6295** may add additional static mutexes.  Static mutexes are for internal
6296** use by SQLite only.  Applications that use SQLite mutexes should
6297** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
6300** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
6301** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
6302** returns a different mutex on every call.  ^For the static
6303** mutex types, the same mutex is returned on every call that has
6304** the same type number.
6306** ^The sqlite3_mutex_free() routine deallocates a previously
6307** allocated dynamic mutex.  Attempting to deallocate a static
6308** mutex results in undefined behavior.
6310** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
6311** to enter a mutex.  ^If another thread is already within the mutex,
6312** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
6313** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
6314** upon successful entry.  ^(Mutexes created using
6315** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
6316** In such cases, the
6317** mutex must be exited an equal number of times before another thread
6318** can enter.)^  If the same thread tries to enter any mutex other
6319** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
6321** ^(Some systems (for example, Windows 95) do not support the operation
6322** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
6323** will always return SQLITE_BUSY. The SQLite core only ever uses
6324** sqlite3_mutex_try() as an optimization so this is acceptable
6325** behavior.)^
6327** ^The sqlite3_mutex_leave() routine exits a mutex that was
6328** previously entered by the same thread.   The behavior
6329** is undefined if the mutex is not currently entered by the
6330** calling thread or is not currently allocated.
6332** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
6333** sqlite3_mutex_leave() is a NULL pointer, then all three routines
6334** behave as no-ops.
6336** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
6338SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_mutex_alloc(int);
6339SQLITE_API void SQLITE_STDCALL sqlite3_mutex_free(sqlite3_mutex*);
6340SQLITE_API void SQLITE_STDCALL sqlite3_mutex_enter(sqlite3_mutex*);
6341SQLITE_API int SQLITE_STDCALL sqlite3_mutex_try(sqlite3_mutex*);
6342SQLITE_API void SQLITE_STDCALL sqlite3_mutex_leave(sqlite3_mutex*);
6345** CAPI3REF: Mutex Methods Object
6347** An instance of this structure defines the low-level routines
6348** used to allocate and use mutexes.
6350** Usually, the default mutex implementations provided by SQLite are
6351** sufficient, however the application has the option of substituting a custom
6352** implementation for specialized deployments or systems for which SQLite
6353** does not provide a suitable implementation. In this case, the application
6354** creates and populates an instance of this structure to pass
6355** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
6356** Additionally, an instance of this structure can be used as an
6357** output variable when querying the system for the current mutex
6358** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
6360** ^The xMutexInit method defined by this structure is invoked as
6361** part of system initialization by the sqlite3_initialize() function.
6362** ^The xMutexInit routine is called by SQLite exactly once for each
6363** effective call to [sqlite3_initialize()].
6365** ^The xMutexEnd method defined by this structure is invoked as
6366** part of system shutdown by the sqlite3_shutdown() function. The
6367** implementation of this method is expected to release all outstanding
6368** resources obtained by the mutex methods implementation, especially
6369** those obtained by the xMutexInit method.  ^The xMutexEnd()
6370** interface is invoked exactly once for each call to [sqlite3_shutdown()].
6372** ^(The remaining seven methods defined by this structure (xMutexAlloc,
6373** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
6374** xMutexNotheld) implement the following interfaces (respectively):
6376** <ul>
6377**   <li>  [sqlite3_mutex_alloc()] </li>
6378**   <li>  [sqlite3_mutex_free()] </li>
6379**   <li>  [sqlite3_mutex_enter()] </li>
6380**   <li>  [sqlite3_mutex_try()] </li>
6381**   <li>  [sqlite3_mutex_leave()] </li>
6382**   <li>  [sqlite3_mutex_held()] </li>
6383**   <li>  [sqlite3_mutex_notheld()] </li>
6384** </ul>)^
6386** The only difference is that the public sqlite3_XXX functions enumerated
6387** above silently ignore any invocations that pass a NULL pointer instead
6388** of a valid mutex handle. The implementations of the methods defined
6389** by this structure are not required to handle this case, the results
6390** of passing a NULL pointer instead of a valid mutex handle are undefined
6391** (i.e. it is acceptable to provide an implementation that segfaults if
6392** it is passed a NULL pointer).
6394** The xMutexInit() method must be threadsafe.  It must be harmless to
6395** invoke xMutexInit() multiple times within the same process and without
6396** intervening calls to xMutexEnd().  Second and subsequent calls to
6397** xMutexInit() must be no-ops.
6399** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
6400** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
6401** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
6402** memory allocation for a fast or recursive mutex.
6404** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
6405** called, but only if the prior call to xMutexInit returned SQLITE_OK.
6406** If xMutexInit fails in any way, it is expected to clean up after itself
6407** prior to returning.
6409typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
6410struct sqlite3_mutex_methods {
6411  int (*xMutexInit)(void);
6412  int (*xMutexEnd)(void);
6413  sqlite3_mutex *(*xMutexAlloc)(int);
6414  void (*xMutexFree)(sqlite3_mutex *);
6415  void (*xMutexEnter)(sqlite3_mutex *);
6416  int (*xMutexTry)(sqlite3_mutex *);
6417  void (*xMutexLeave)(sqlite3_mutex *);
6418  int (*xMutexHeld)(sqlite3_mutex *);
6419  int (*xMutexNotheld)(sqlite3_mutex *);
6423** CAPI3REF: Mutex Verification Routines
6425** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
6426** are intended for use inside assert() statements.  The SQLite core
6427** never uses these routines except inside an assert() and applications
6428** are advised to follow the lead of the core.  The SQLite core only
6429** provides implementations for these routines when it is compiled
6430** with the SQLITE_DEBUG flag.  External mutex implementations
6431** are only required to provide these routines if SQLITE_DEBUG is
6432** defined and if NDEBUG is not defined.
6434** These routines should return true if the mutex in their argument
6435** is held or not held, respectively, by the calling thread.
6437** The implementation is not required to provide versions of these
6438** routines that actually work. If the implementation does not provide working
6439** versions of these routines, it should at least provide stubs that always
6440** return true so that one does not get spurious assertion failures.
6442** If the argument to sqlite3_mutex_held() is a NULL pointer then
6443** the routine should return 1.   This seems counter-intuitive since
6444** clearly the mutex cannot be held if it does not exist.  But
6445** the reason the mutex does not exist is because the build is not
6446** using mutexes.  And we do not want the assert() containing the
6447** call to sqlite3_mutex_held() to fail, so a non-zero return is
6448** the appropriate thing to do.  The sqlite3_mutex_notheld()
6449** interface should also return 1 when given a NULL pointer.
6451#ifndef NDEBUG
6452SQLITE_API int SQLITE_STDCALL sqlite3_mutex_held(sqlite3_mutex*);
6453SQLITE_API int SQLITE_STDCALL sqlite3_mutex_notheld(sqlite3_mutex*);
6457** CAPI3REF: Mutex Types
6459** The [sqlite3_mutex_alloc()] interface takes a single argument
6460** which is one of these integer constants.
6462** The set of static mutexes may change from one SQLite release to the
6463** next.  Applications that override the built-in mutex logic must be
6464** prepared to accommodate additional static mutexes.
6466#define SQLITE_MUTEX_FAST             0
6467#define SQLITE_MUTEX_RECURSIVE        1
6469#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
6470#define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
6471#define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
6472#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
6473#define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
6474#define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
6475#define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
6476#define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
6477#define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
6478#define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
6481** CAPI3REF: Retrieve the mutex for a database connection
6482** METHOD: sqlite3
6484** ^This interface returns a pointer the [sqlite3_mutex] object that
6485** serializes access to the [database connection] given in the argument
6486** when the [threading mode] is Serialized.
6487** ^If the [threading mode] is Single-thread or Multi-thread then this
6488** routine returns a NULL pointer.
6490SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_db_mutex(sqlite3*);
6493** CAPI3REF: Low-Level Control Of Database Files
6494** METHOD: sqlite3
6496** ^The [sqlite3_file_control()] interface makes a direct call to the
6497** xFileControl method for the [sqlite3_io_methods] object associated
6498** with a particular database identified by the second argument. ^The
6499** name of the database is "main" for the main database or "temp" for the
6500** TEMP database, or the name that appears after the AS keyword for
6501** databases that are added using the [ATTACH] SQL command.
6502** ^A NULL pointer can be used in place of "main" to refer to the
6503** main database file.
6504** ^The third and fourth parameters to this routine
6505** are passed directly through to the second and third parameters of
6506** the xFileControl method.  ^The return value of the xFileControl
6507** method becomes the return value of this routine.
6509** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
6510** a pointer to the underlying [sqlite3_file] object to be written into
6511** the space pointed to by the 4th parameter.  ^The SQLITE_FCNTL_FILE_POINTER
6512** case is a short-circuit path which does not actually invoke the
6513** underlying sqlite3_io_methods.xFileControl method.
6515** ^If the second parameter (zDbName) does not match the name of any
6516** open database file, then SQLITE_ERROR is returned.  ^This error
6517** code is not remembered and will not be recalled by [sqlite3_errcode()]
6518** or [sqlite3_errmsg()].  The underlying xFileControl method might
6519** also return SQLITE_ERROR.  There is no way to distinguish between
6520** an incorrect zDbName and an SQLITE_ERROR return from the underlying
6521** xFileControl method.
6525SQLITE_API int SQLITE_STDCALL sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
6528** CAPI3REF: Testing Interface
6530** ^The sqlite3_test_control() interface is used to read out internal
6531** state of SQLite and to inject faults into SQLite for testing
6532** purposes.  ^The first parameter is an operation code that determines
6533** the number, meaning, and operation of all subsequent parameters.
6535** This interface is not for use by applications.  It exists solely
6536** for verifying the correct operation of the SQLite library.  Depending
6537** on how the SQLite library is compiled, this interface might not exist.
6539** The details of the operation codes, their meanings, the parameters
6540** they take, and what they do are all subject to change without notice.
6541** Unlike most of the SQLite API, this function is not guaranteed to
6542** operate consistently from one release to the next.
6544SQLITE_API int SQLITE_CDECL sqlite3_test_control(int op, ...);
6547** CAPI3REF: Testing Interface Operation Codes
6549** These constants are the valid operation code parameters used
6550** as the first argument to [sqlite3_test_control()].
6552** These parameters and their meanings are subject to change
6553** without notice.  These values are for testing purposes only.
6554** Applications should not use any of these parameters or the
6555** [sqlite3_test_control()] interface.
6557#define SQLITE_TESTCTRL_FIRST                    5
6558#define SQLITE_TESTCTRL_PRNG_SAVE                5
6559#define SQLITE_TESTCTRL_PRNG_RESTORE             6
6560#define SQLITE_TESTCTRL_PRNG_RESET               7
6561#define SQLITE_TESTCTRL_BITVEC_TEST              8
6562#define SQLITE_TESTCTRL_FAULT_INSTALL            9
6564#define SQLITE_TESTCTRL_PENDING_BYTE            11
6565#define SQLITE_TESTCTRL_ASSERT                  12
6566#define SQLITE_TESTCTRL_ALWAYS                  13
6567#define SQLITE_TESTCTRL_RESERVE                 14
6568#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
6569#define SQLITE_TESTCTRL_ISKEYWORD               16
6570#define SQLITE_TESTCTRL_SCRATCHMALLOC           17
6572#define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
6573#define SQLITE_TESTCTRL_NEVER_CORRUPT           20
6574#define SQLITE_TESTCTRL_VDBE_COVERAGE           21
6575#define SQLITE_TESTCTRL_BYTEORDER               22
6576#define SQLITE_TESTCTRL_ISINIT                  23
6577#define SQLITE_TESTCTRL_SORTER_MMAP             24
6578#define SQLITE_TESTCTRL_IMPOSTER                25
6579#define SQLITE_TESTCTRL_LAST                    25
6582** CAPI3REF: SQLite Runtime Status
6584** ^These interfaces are used to retrieve runtime status information
6585** about the performance of SQLite, and optionally to reset various
6586** highwater marks.  ^The first argument is an integer code for
6587** the specific parameter to measure.  ^(Recognized integer codes
6588** are of the form [status parameters | SQLITE_STATUS_...].)^
6589** ^The current value of the parameter is returned into *pCurrent.
6590** ^The highest recorded value is returned in *pHighwater.  ^If the
6591** resetFlag is true, then the highest record value is reset after
6592** *pHighwater is written.  ^(Some parameters do not record the highest
6593** value.  For those parameters
6594** nothing is written into *pHighwater and the resetFlag is ignored.)^
6595** ^(Other parameters record only the highwater mark and not the current
6596** value.  For these latter parameters nothing is written into *pCurrent.)^
6598** ^The sqlite3_status() and sqlite3_status64() routines return
6599** SQLITE_OK on success and a non-zero [error code] on failure.
6601** If either the current value or the highwater mark is too large to
6602** be represented by a 32-bit integer, then the values returned by
6603** sqlite3_status() are undefined.
6605** See also: [sqlite3_db_status()]
6607SQLITE_API int SQLITE_STDCALL sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
6608SQLITE_API int SQLITE_STDCALL sqlite3_status64(
6609  int op,
6610  sqlite3_int64 *pCurrent,
6611  sqlite3_int64 *pHighwater,
6612  int resetFlag
6617** CAPI3REF: Status Parameters
6618** KEYWORDS: {status parameters}
6620** These integer constants designate various run-time status parameters
6621** that can be returned by [sqlite3_status()].
6623** <dl>
6625** <dd>This parameter is the current amount of memory checked out
6626** using [sqlite3_malloc()], either directly or indirectly.  The
6627** figure includes calls made to [sqlite3_malloc()] by the application
6628** and internal memory usage by the SQLite library.  Scratch memory
6629** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
6630** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
6631** this parameter.  The amount returned is the sum of the allocation
6632** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
6635** <dd>This parameter records the largest memory allocation request
6636** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
6637** internal equivalents).  Only the value returned in the
6638** *pHighwater parameter to [sqlite3_status()] is of interest.
6639** The value written into the *pCurrent parameter is undefined.</dd>)^
6642** <dd>This parameter records the number of separate memory allocations
6643** currently checked out.</dd>)^
6646** <dd>This parameter returns the number of pages used out of the
6647** [pagecache memory allocator] that was configured using
6649** value returned is in pages, not in bytes.</dd>)^
6653** <dd>This parameter returns the number of bytes of page cache
6654** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
6655** buffer and where forced to overflow to [sqlite3_malloc()].  The
6656** returned value includes allocations that overflowed because they
6657** where too large (they were larger than the "sz" parameter to
6658** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
6659** no space was left in the page cache.</dd>)^
6662** <dd>This parameter records the largest memory allocation request
6663** handed to [pagecache memory allocator].  Only the value returned in the
6664** *pHighwater parameter to [sqlite3_status()] is of interest.
6665** The value written into the *pCurrent parameter is undefined.</dd>)^
6668** <dd>This parameter returns the number of allocations used out of the
6669** [scratch memory allocator] configured using
6670** [SQLITE_CONFIG_SCRATCH].  The value returned is in allocations, not
6671** in bytes.  Since a single thread may only have one scratch allocation
6672** outstanding at time, this parameter also reports the number of threads
6673** using scratch memory at the same time.</dd>)^
6676** <dd>This parameter returns the number of bytes of scratch memory
6677** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
6678** buffer and where forced to overflow to [sqlite3_malloc()].  The values
6679** returned include overflows because the requested allocation was too
6680** larger (that is, because the requested allocation was larger than the
6681** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
6682** slots were available.
6683** </dd>)^
6686** <dd>This parameter records the largest memory allocation request
6687** handed to [scratch memory allocator].  Only the value returned in the
6688** *pHighwater parameter to [sqlite3_status()] is of interest.
6689** The value written into the *pCurrent parameter is undefined.</dd>)^
6692** <dd>This parameter records the deepest parser stack.  It is only
6693** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
6694** </dl>
6696** New status parameters may be added from time to time.
6698#define SQLITE_STATUS_MEMORY_USED          0
6701#define SQLITE_STATUS_SCRATCH_USED         3
6703#define SQLITE_STATUS_MALLOC_SIZE          5
6704#define SQLITE_STATUS_PARSER_STACK         6
6706#define SQLITE_STATUS_SCRATCH_SIZE         8
6707#define SQLITE_STATUS_MALLOC_COUNT         9
6710** CAPI3REF: Database Connection Status
6711** METHOD: sqlite3
6713** ^This interface is used to retrieve runtime status information
6714** about a single [database connection].  ^The first argument is the
6715** database connection object to be interrogated.  ^The second argument
6716** is an integer constant, taken from the set of
6717** [SQLITE_DBSTATUS options], that
6718** determines the parameter to interrogate.  The set of
6719** [SQLITE_DBSTATUS options] is likely
6720** to grow in future releases of SQLite.
6722** ^The current value of the requested parameter is written into *pCur
6723** and the highest instantaneous value is written into *pHiwtr.  ^If
6724** the resetFlg is true, then the highest instantaneous value is
6725** reset back down to the current value.
6727** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
6728** non-zero [error code] on failure.
6730** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
6732SQLITE_API int SQLITE_STDCALL sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
6735** CAPI3REF: Status Parameters for database connections
6738** These constants are the available integer "verbs" that can be passed as
6739** the second argument to the [sqlite3_db_status()] interface.
6741** New verbs may be added in future releases of SQLite. Existing verbs
6742** might be discontinued. Applications should check the return code from
6743** [sqlite3_db_status()] to make sure that the call worked.
6744** The [sqlite3_db_status()] interface will return a non-zero error code
6745** if a discontinued or unsupported verb is invoked.
6747** <dl>
6749** <dd>This parameter returns the number of lookaside memory slots currently
6750** checked out.</dd>)^
6753** <dd>This parameter returns the number malloc attempts that were
6754** satisfied using lookaside memory. Only the high-water value is meaningful;
6755** the current value is always zero.)^
6759** <dd>This parameter returns the number malloc attempts that might have
6760** been satisfied using lookaside memory but failed due to the amount of
6761** memory requested being larger than the lookaside slot size.
6762** Only the high-water value is meaningful;
6763** the current value is always zero.)^
6767** <dd>This parameter returns the number malloc attempts that might have
6768** been satisfied using lookaside memory but failed due to all lookaside
6769** memory already being in use.
6770** Only the high-water value is meaningful;
6771** the current value is always zero.)^
6774** <dd>This parameter returns the approximate number of bytes of heap
6775** memory used by all pager caches associated with the database connection.)^
6776** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
6779** <dd>This parameter returns the approximate number of bytes of heap
6780** memory used to store the schema for all databases associated
6781** with the connection - main, temp, and any [ATTACH]-ed databases.)^
6782** ^The full amount of memory used by the schemas is reported, even if the
6783** schema memory is shared with other database connections due to
6784** [shared cache mode] being enabled.
6785** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
6788** <dd>This parameter returns the approximate number of bytes of heap
6789** and lookaside memory used by all prepared statements associated with
6790** the database connection.)^
6791** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
6792** </dd>
6795** <dd>This parameter returns the number of pager cache hits that have
6796** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
6797** is always 0.
6798** </dd>
6801** <dd>This parameter returns the number of pager cache misses that have
6802** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
6803** is always 0.
6804** </dd>
6807** <dd>This parameter returns the number of dirty cache entries that have
6808** been written to disk. Specifically, the number of pages written to the
6809** wal file in wal mode databases, or the number of pages written to the
6810** database file in rollback mode databases. Any pages written as part of
6811** transaction rollback or database recovery operations are not included.
6812** If an IO or other error occurs while writing a page to disk, the effect
6813** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
6814** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
6815** </dd>
6818** <dd>This parameter returns zero for the current value if and only if
6819** all foreign key constraints (deferred or immediate) have been
6820** resolved.)^  ^The highwater mark is always 0.
6821** </dd>
6822** </dl>
6825#define SQLITE_DBSTATUS_CACHE_USED           1
6826#define SQLITE_DBSTATUS_SCHEMA_USED          2
6827#define SQLITE_DBSTATUS_STMT_USED            3
6831#define SQLITE_DBSTATUS_CACHE_HIT            7
6832#define SQLITE_DBSTATUS_CACHE_MISS           8
6833#define SQLITE_DBSTATUS_CACHE_WRITE          9
6834#define SQLITE_DBSTATUS_DEFERRED_FKS        10
6835#define SQLITE_DBSTATUS_MAX                 10   /* Largest defined DBSTATUS */
6839** CAPI3REF: Prepared Statement Status
6840** METHOD: sqlite3_stmt
6842** ^(Each prepared statement maintains various
6843** [SQLITE_STMTSTATUS counters] that measure the number
6844** of times it has performed specific operations.)^  These counters can
6845** be used to monitor the performance characteristics of the prepared
6846** statements.  For example, if the number of table steps greatly exceeds
6847** the number of table searches or result rows, that would tend to indicate
6848** that the prepared statement is using a full table scan rather than
6849** an index.
6851** ^(This interface is used to retrieve and reset counter values from
6852** a [prepared statement].  The first argument is the prepared statement
6853** object to be interrogated.  The second argument
6854** is an integer code for a specific [SQLITE_STMTSTATUS counter]
6855** to be interrogated.)^
6856** ^The current value of the requested counter is returned.
6857** ^If the resetFlg is true, then the counter is reset to zero after this
6858** interface call returns.
6860** See also: [sqlite3_status()] and [sqlite3_db_status()].
6862SQLITE_API int SQLITE_STDCALL sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
6865** CAPI3REF: Status Parameters for prepared statements
6868** These preprocessor macros define integer codes that name counter
6869** values associated with the [sqlite3_stmt_status()] interface.
6870** The meanings of the various counters are as follows:
6872** <dl>
6874** <dd>^This is the number of times that SQLite has stepped forward in
6875** a table as part of a full table scan.  Large numbers for this counter
6876** may indicate opportunities for performance improvement through
6877** careful use of indices.</dd>
6880** <dd>^This is the number of sort operations that have occurred.
6881** A non-zero value in this counter may indicate an opportunity to
6882** improvement performance through careful use of indices.</dd>
6885** <dd>^This is the number of rows inserted into transient indices that
6886** were created automatically in order to help joins run faster.
6887** A non-zero value in this counter may indicate an opportunity to
6888** improvement performance by adding permanent indices that do not
6889** need to be reinitialized each time the statement is run.</dd>
6892** <dd>^This is the number of virtual machine operations executed
6893** by the prepared statement if that number is less than or equal
6894** to 2147483647.  The number of virtual machine operations can be
6895** used as a proxy for the total work done by the prepared statement.
6896** If the number of virtual machine operations exceeds 2147483647
6897** then the value returned by this statement status code is undefined.
6898** </dd>
6899** </dl>
6902#define SQLITE_STMTSTATUS_SORT              2
6904#define SQLITE_STMTSTATUS_VM_STEP           4
6907** CAPI3REF: Custom Page Cache Object
6909** The sqlite3_pcache type is opaque.  It is implemented by
6910** the pluggable module.  The SQLite core has no knowledge of
6911** its size or internal structure and never deals with the
6912** sqlite3_pcache object except by holding and passing pointers
6913** to the object.
6915** See [sqlite3_pcache_methods2] for additional information.
6917typedef struct sqlite3_pcache sqlite3_pcache;
6920** CAPI3REF: Custom Page Cache Object
6922** The sqlite3_pcache_page object represents a single page in the
6923** page cache.  The page cache will allocate instances of this
6924** object.  Various methods of the page cache use pointers to instances
6925** of this object as parameters or as their return value.
6927** See [sqlite3_pcache_methods2] for additional information.
6929typedef struct sqlite3_pcache_page sqlite3_pcache_page;
6930struct sqlite3_pcache_page {
6931  void *pBuf;        /* The content of the page */
6932  void *pExtra;      /* Extra information associated with the page */
6936** CAPI3REF: Application Defined Page Cache.
6937** KEYWORDS: {page cache}
6939** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
6940** register an alternative page cache implementation by passing in an
6941** instance of the sqlite3_pcache_methods2 structure.)^
6942** In many applications, most of the heap memory allocated by
6943** SQLite is used for the page cache.
6944** By implementing a
6945** custom page cache using this API, an application can better control
6946** the amount of memory consumed by SQLite, the way in which
6947** that memory is allocated and released, and the policies used to
6948** determine exactly which parts of a database file are cached and for
6949** how long.
6951** The alternative page cache mechanism is an
6952** extreme measure that is only needed by the most demanding applications.
6953** The built-in page cache is recommended for most uses.
6955** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
6956** internal buffer by SQLite within the call to [sqlite3_config].  Hence
6957** the application may discard the parameter after the call to
6958** [sqlite3_config()] returns.)^
6960** [[the xInit() page cache method]]
6961** ^(The xInit() method is called once for each effective
6962** call to [sqlite3_initialize()])^
6963** (usually only once during the lifetime of the process). ^(The xInit()
6964** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
6965** The intent of the xInit() method is to set up global data structures
6966** required by the custom page cache implementation.
6967** ^(If the xInit() method is NULL, then the
6968** built-in default page cache is used instead of the application defined
6969** page cache.)^
6971** [[the xShutdown() page cache method]]
6972** ^The xShutdown() method is called by [sqlite3_shutdown()].
6973** It can be used to clean up
6974** any outstanding resources before process shutdown, if required.
6975** ^The xShutdown() method may be NULL.
6977** ^SQLite automatically serializes calls to the xInit method,
6978** so the xInit method need not be threadsafe.  ^The
6979** xShutdown method is only called from [sqlite3_shutdown()] so it does
6980** not need to be threadsafe either.  All other methods must be threadsafe
6981** in multithreaded applications.
6983** ^SQLite will never invoke xInit() more than once without an intervening
6984** call to xShutdown().
6986** [[the xCreate() page cache methods]]
6987** ^SQLite invokes the xCreate() method to construct a new cache instance.
6988** SQLite will typically create one cache instance for each open database file,
6989** though this is not guaranteed. ^The
6990** first parameter, szPage, is the size in bytes of the pages that must
6991** be allocated by the cache.  ^szPage will always a power of two.  ^The
6992** second parameter szExtra is a number of bytes of extra storage
6993** associated with each page cache entry.  ^The szExtra parameter will
6994** a number less than 250.  SQLite will use the
6995** extra szExtra bytes on each page to store metadata about the underlying
6996** database page on disk.  The value passed into szExtra depends
6997** on the SQLite version, the target platform, and how SQLite was compiled.
6998** ^The third argument to xCreate(), bPurgeable, is true if the cache being
6999** created will be used to cache database pages of a file stored on disk, or
7000** false if it is used for an in-memory database. The cache implementation
7001** does not have to do anything special based with the value of bPurgeable;
7002** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
7003** never invoke xUnpin() except to deliberately delete a page.
7004** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
7005** false will always have the "discard" flag set to true.
7006** ^Hence, a cache created with bPurgeable false will
7007** never contain any unpinned pages.
7009** [[the xCachesize() page cache method]]
7010** ^(The xCachesize() method may be called at any time by SQLite to set the
7011** suggested maximum cache-size (number of pages stored by) the cache
7012** instance passed as the first argument. This is the value configured using
7013** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
7014** parameter, the implementation is not required to do anything with this
7015** value; it is advisory only.
7017** [[the xPagecount() page cache methods]]
7018** The xPagecount() method must return the number of pages currently
7019** stored in the cache, both pinned and unpinned.
7021** [[the xFetch() page cache methods]]
7022** The xFetch() method locates a page in the cache and returns a pointer to
7023** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
7024** The pBuf element of the returned sqlite3_pcache_page object will be a
7025** pointer to a buffer of szPage bytes used to store the content of a
7026** single database page.  The pExtra element of sqlite3_pcache_page will be
7027** a pointer to the szExtra bytes of extra storage that SQLite has requested
7028** for each entry in the page cache.
7030** The page to be fetched is determined by the key. ^The minimum key value
7031** is 1.  After it has been retrieved using xFetch, the page is considered
7032** to be "pinned".
7034** If the requested page is already in the page cache, then the page cache
7035** implementation must return a pointer to the page buffer with its content
7036** intact.  If the requested page is not already in the cache, then the
7037** cache implementation should use the value of the createFlag
7038** parameter to help it determined what action to take:
7040** <table border=1 width=85% align=center>
7041** <tr><th> createFlag <th> Behavior when page is not already in cache
7042** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
7043** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
7044**                 Otherwise return NULL.
7045** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
7046**                 NULL if allocating a new page is effectively impossible.
7047** </table>
7049** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
7050** will only use a createFlag of 2 after a prior call with a createFlag of 1
7051** failed.)^  In between the to xFetch() calls, SQLite may
7052** attempt to unpin one or more cache pages by spilling the content of
7053** pinned pages to disk and synching the operating system disk cache.
7055** [[the xUnpin() page cache method]]
7056** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
7057** as its second argument.  If the third parameter, discard, is non-zero,
7058** then the page must be evicted from the cache.
7059** ^If the discard parameter is
7060** zero, then the page may be discarded or retained at the discretion of
7061** page cache implementation. ^The page cache implementation
7062** may choose to evict unpinned pages at any time.
7064** The cache must not perform any reference counting. A single
7065** call to xUnpin() unpins the page regardless of the number of prior calls
7066** to xFetch().
7068** [[the xRekey() page cache methods]]
7069** The xRekey() method is used to change the key value associated with the
7070** page passed as the second argument. If the cache
7071** previously contains an entry associated with newKey, it must be
7072** discarded. ^Any prior cache entry associated with newKey is guaranteed not
7073** to be pinned.
7075** When SQLite calls the xTruncate() method, the cache must discard all
7076** existing cache entries with page numbers (keys) greater than or equal
7077** to the value of the iLimit parameter passed to xTruncate(). If any
7078** of these pages are pinned, they are implicitly unpinned, meaning that
7079** they can be safely discarded.
7081** [[the xDestroy() page cache method]]
7082** ^The xDestroy() method is used to delete a cache allocated by xCreate().
7083** All resources associated with the specified cache should be freed. ^After
7084** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
7085** handle invalid, and will not use it with any other sqlite3_pcache_methods2
7086** functions.
7088** [[the xShrink() page cache method]]
7089** ^SQLite invokes the xShrink() method when it wants the page cache to
7090** free up as much of heap memory as possible.  The page cache implementation
7091** is not obligated to free any memory, but well-behaved implementations should
7092** do their best.
7094typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
7095struct sqlite3_pcache_methods2 {
7096  int iVersion;
7097  void *pArg;
7098  int (*xInit)(void*);
7099  void (*xShutdown)(void*);
7100  sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
7101  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
7102  int (*xPagecount)(sqlite3_pcache*);
7103  sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
7104  void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
7105  void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
7106      unsigned oldKey, unsigned newKey);
7107  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
7108  void (*xDestroy)(sqlite3_pcache*);
7109  void (*xShrink)(sqlite3_pcache*);
7113** This is the obsolete pcache_methods object that has now been replaced
7114** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
7115** retained in the header file for backwards compatibility only.
7117typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
7118struct sqlite3_pcache_methods {
7119  void *pArg;
7120  int (*xInit)(void*);
7121  void (*xShutdown)(void*);
7122  sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
7123  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
7124  int (*xPagecount)(sqlite3_pcache*);
7125  void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
7126  void (*xUnpin)(sqlite3_pcache*, void*, int discard);
7127  void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
7128  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
7129  void (*xDestroy)(sqlite3_pcache*);
7134** CAPI3REF: Online Backup Object
7136** The sqlite3_backup object records state information about an ongoing
7137** online backup operation.  ^The sqlite3_backup object is created by
7138** a call to [sqlite3_backup_init()] and is destroyed by a call to
7139** [sqlite3_backup_finish()].
7141** See Also: [Using the SQLite Online Backup API]
7143typedef struct sqlite3_backup sqlite3_backup;
7146** CAPI3REF: Online Backup API.
7148** The backup API copies the content of one database into another.
7149** It is useful either for creating backups of databases or
7150** for copying in-memory databases to or from persistent files.
7152** See Also: [Using the SQLite Online Backup API]
7154** ^SQLite holds a write transaction open on the destination database file
7155** for the duration of the backup operation.
7156** ^The source database is read-locked only while it is being read;
7157** it is not locked continuously for the entire backup operation.
7158** ^Thus, the backup may be performed on a live source database without
7159** preventing other database connections from
7160** reading or writing to the source database while the backup is underway.
7162** ^(To perform a backup operation:
7163**   <ol>
7164**     <li><b>sqlite3_backup_init()</b> is called once to initialize the
7165**         backup,
7166**     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
7167**         the data between the two databases, and finally
7168**     <li><b>sqlite3_backup_finish()</b> is called to release all resources
7169**         associated with the backup operation.
7170**   </ol>)^
7171** There should be exactly one call to sqlite3_backup_finish() for each
7172** successful call to sqlite3_backup_init().
7174** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
7176** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
7177** [database connection] associated with the destination database
7178** and the database name, respectively.
7179** ^The database name is "main" for the main database, "temp" for the
7180** temporary database, or the name specified after the AS keyword in
7181** an [ATTACH] statement for an attached database.
7182** ^The S and M arguments passed to
7183** sqlite3_backup_init(D,N,S,M) identify the [database connection]
7184** and database name of the source database, respectively.
7185** ^The source and destination [database connections] (parameters S and D)
7186** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
7187** an error.
7189** ^A call to sqlite3_backup_init() will fail, returning SQLITE_ERROR, if
7190** there is already a read or read-write transaction open on the
7191** destination database.
7193** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
7194** returned and an error code and error message are stored in the
7195** destination [database connection] D.
7196** ^The error code and message for the failed call to sqlite3_backup_init()
7197** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
7198** [sqlite3_errmsg16()] functions.
7199** ^A successful call to sqlite3_backup_init() returns a pointer to an
7200** [sqlite3_backup] object.
7201** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
7202** sqlite3_backup_finish() functions to perform the specified backup
7203** operation.
7205** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
7207** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
7208** the source and destination databases specified by [sqlite3_backup] object B.
7209** ^If N is negative, all remaining source pages are copied.
7210** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
7211** are still more pages to be copied, then the function returns [SQLITE_OK].
7212** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
7213** from source to destination, then it returns [SQLITE_DONE].
7214** ^If an error occurs while running sqlite3_backup_step(B,N),
7215** then an [error code] is returned. ^As well as [SQLITE_OK] and
7216** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
7218** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
7220** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
7221** <ol>
7222** <li> the destination database was opened read-only, or
7223** <li> the destination database is using write-ahead-log journaling
7224** and the destination and source page sizes differ, or
7225** <li> the destination database is an in-memory database and the
7226** destination and source page sizes differ.
7227** </ol>)^
7229** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
7230** the [sqlite3_busy_handler | busy-handler function]
7231** is invoked (if one is specified). ^If the
7232** busy-handler returns non-zero before the lock is available, then
7233** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
7234** sqlite3_backup_step() can be retried later. ^If the source
7235** [database connection]
7236** is being used to write to the source database when sqlite3_backup_step()
7237** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
7238** case the call to sqlite3_backup_step() can be retried later on. ^(If
7240** [SQLITE_READONLY] is returned, then
7241** there is no point in retrying the call to sqlite3_backup_step(). These
7242** errors are considered fatal.)^  The application must accept
7243** that the backup operation has failed and pass the backup operation handle
7244** to the sqlite3_backup_finish() to release associated resources.
7246** ^The first call to sqlite3_backup_step() obtains an exclusive lock
7247** on the destination file. ^The exclusive lock is not released until either
7248** sqlite3_backup_finish() is called or the backup operation is complete
7249** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
7250** sqlite3_backup_step() obtains a [shared lock] on the source database that
7251** lasts for the duration of the sqlite3_backup_step() call.
7252** ^Because the source database is not locked between calls to
7253** sqlite3_backup_step(), the source database may be modified mid-way
7254** through the backup process.  ^If the source database is modified by an
7255** external process or via a database connection other than the one being
7256** used by the backup operation, then the backup will be automatically
7257** restarted by the next call to sqlite3_backup_step(). ^If the source
7258** database is modified by the using the same database connection as is used
7259** by the backup operation, then the backup database is automatically
7260** updated at the same time.
7262** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
7264** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
7265** application wishes to abandon the backup operation, the application
7266** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
7267** ^The sqlite3_backup_finish() interfaces releases all
7268** resources associated with the [sqlite3_backup] object.
7269** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
7270** active write-transaction on the destination database is rolled back.
7271** The [sqlite3_backup] object is invalid
7272** and may not be used following a call to sqlite3_backup_finish().
7274** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
7275** sqlite3_backup_step() errors occurred, regardless or whether or not
7276** sqlite3_backup_step() completed.
7277** ^If an out-of-memory condition or IO error occurred during any prior
7278** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
7279** sqlite3_backup_finish() returns the corresponding [error code].
7281** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
7282** is not a permanent error and does not affect the return value of
7283** sqlite3_backup_finish().
7285** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
7286** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
7288** ^The sqlite3_backup_remaining() routine returns the number of pages still
7289** to be backed up at the conclusion of the most recent sqlite3_backup_step().
7290** ^The sqlite3_backup_pagecount() routine returns the total number of pages
7291** in the source database at the conclusion of the most recent
7292** sqlite3_backup_step().
7293** ^(The values returned by these functions are only updated by
7294** sqlite3_backup_step(). If the source database is modified in a way that
7295** changes the size of the source database or the number of pages remaining,
7296** those changes are not reflected in the output of sqlite3_backup_pagecount()
7297** and sqlite3_backup_remaining() until after the next
7298** sqlite3_backup_step().)^
7300** <b>Concurrent Usage of Database Handles</b>
7302** ^The source [database connection] may be used by the application for other
7303** purposes while a backup operation is underway or being initialized.
7304** ^If SQLite is compiled and configured to support threadsafe database
7305** connections, then the source database connection may be used concurrently
7306** from within other threads.
7308** However, the application must guarantee that the destination
7309** [database connection] is not passed to any other API (by any thread) after
7310** sqlite3_backup_init() is called and before the corresponding call to
7311** sqlite3_backup_finish().  SQLite does not currently check to see
7312** if the application incorrectly accesses the destination [database connection]
7313** and so no error code is reported, but the operations may malfunction
7314** nevertheless.  Use of the destination database connection while a
7315** backup is in progress might also also cause a mutex deadlock.
7317** If running in [shared cache mode], the application must
7318** guarantee that the shared cache used by the destination database
7319** is not accessed while the backup is running. In practice this means
7320** that the application must guarantee that the disk file being
7321** backed up to is not accessed by any connection within the process,
7322** not just the specific connection that was passed to sqlite3_backup_init().
7324** The [sqlite3_backup] object itself is partially threadsafe. Multiple
7325** threads may safely make multiple concurrent calls to sqlite3_backup_step().
7326** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
7327** APIs are not strictly speaking threadsafe. If they are invoked at the
7328** same time as another thread is invoking sqlite3_backup_step() it is
7329** possible that they return invalid values.
7331SQLITE_API sqlite3_backup *SQLITE_STDCALL sqlite3_backup_init(
7332  sqlite3 *pDest,                        /* Destination database handle */
7333  const char *zDestName,                 /* Destination database name */
7334  sqlite3 *pSource,                      /* Source database handle */
7335  const char *zSourceName                /* Source database name */
7337SQLITE_API int SQLITE_STDCALL sqlite3_backup_step(sqlite3_backup *p, int nPage);
7338SQLITE_API int SQLITE_STDCALL sqlite3_backup_finish(sqlite3_backup *p);
7339SQLITE_API int SQLITE_STDCALL sqlite3_backup_remaining(sqlite3_backup *p);
7340SQLITE_API int SQLITE_STDCALL sqlite3_backup_pagecount(sqlite3_backup *p);
7343** CAPI3REF: Unlock Notification
7344** METHOD: sqlite3
7346** ^When running in shared-cache mode, a database operation may fail with
7347** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
7348** individual tables within the shared-cache cannot be obtained. See
7349** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
7350** ^This API may be used to register a callback that SQLite will invoke
7351** when the connection currently holding the required lock relinquishes it.
7352** ^This API is only available if the library was compiled with the
7353** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
7355** See Also: [Using the SQLite Unlock Notification Feature].
7357** ^Shared-cache locks are released when a database connection concludes
7358** its current transaction, either by committing it or rolling it back.
7360** ^When a connection (known as the blocked connection) fails to obtain a
7361** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
7362** identity of the database connection (the blocking connection) that
7363** has locked the required resource is stored internally. ^After an
7364** application receives an SQLITE_LOCKED error, it may call the
7365** sqlite3_unlock_notify() method with the blocked connection handle as
7366** the first argument to register for a callback that will be invoked
7367** when the blocking connections current transaction is concluded. ^The
7368** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
7369** call that concludes the blocking connections transaction.
7371** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
7372** there is a chance that the blocking connection will have already
7373** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
7374** If this happens, then the specified callback is invoked immediately,
7375** from within the call to sqlite3_unlock_notify().)^
7377** ^If the blocked connection is attempting to obtain a write-lock on a
7378** shared-cache table, and more than one other connection currently holds
7379** a read-lock on the same table, then SQLite arbitrarily selects one of
7380** the other connections to use as the blocking connection.
7382** ^(There may be at most one unlock-notify callback registered by a
7383** blocked connection. If sqlite3_unlock_notify() is called when the
7384** blocked connection already has a registered unlock-notify callback,
7385** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
7386** called with a NULL pointer as its second argument, then any existing
7387** unlock-notify callback is canceled. ^The blocked connections
7388** unlock-notify callback may also be canceled by closing the blocked
7389** connection using [sqlite3_close()].
7391** The unlock-notify callback is not reentrant. If an application invokes
7392** any sqlite3_xxx API functions from within an unlock-notify callback, a
7393** crash or deadlock may be the result.
7395** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
7396** returns SQLITE_OK.
7398** <b>Callback Invocation Details</b>
7400** When an unlock-notify callback is registered, the application provides a
7401** single void* pointer that is passed to the callback when it is invoked.
7402** However, the signature of the callback function allows SQLite to pass
7403** it an array of void* context pointers. The first argument passed to
7404** an unlock-notify callback is a pointer to an array of void* pointers,
7405** and the second is the number of entries in the array.
7407** When a blocking connections transaction is concluded, there may be
7408** more than one blocked connection that has registered for an unlock-notify
7409** callback. ^If two or more such blocked connections have specified the
7410** same callback function, then instead of invoking the callback function
7411** multiple times, it is invoked once with the set of void* context pointers
7412** specified by the blocked connections bundled together into an array.
7413** This gives the application an opportunity to prioritize any actions
7414** related to the set of unblocked database connections.
7416** <b>Deadlock Detection</b>
7418** Assuming that after registering for an unlock-notify callback a
7419** database waits for the callback to be issued before taking any further
7420** action (a reasonable assumption), then using this API may cause the
7421** application to deadlock. For example, if connection X is waiting for
7422** connection Y's transaction to be concluded, and similarly connection
7423** Y is waiting on connection X's transaction, then neither connection
7424** will proceed and the system may remain deadlocked indefinitely.
7426** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
7427** detection. ^If a given call to sqlite3_unlock_notify() would put the
7428** system in a deadlocked state, then SQLITE_LOCKED is returned and no
7429** unlock-notify callback is registered. The system is said to be in
7430** a deadlocked state if connection A has registered for an unlock-notify
7431** callback on the conclusion of connection B's transaction, and connection
7432** B has itself registered for an unlock-notify callback when connection
7433** A's transaction is concluded. ^Indirect deadlock is also detected, so
7434** the system is also considered to be deadlocked if connection B has
7435** registered for an unlock-notify callback on the conclusion of connection
7436** C's transaction, where connection C is waiting on connection A. ^Any
7437** number of levels of indirection are allowed.
7439** <b>The "DROP TABLE" Exception</b>
7441** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
7442** always appropriate to call sqlite3_unlock_notify(). There is however,
7443** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
7444** SQLite checks if there are any currently executing SELECT statements
7445** that belong to the same connection. If there are, SQLITE_LOCKED is
7446** returned. In this case there is no "blocking connection", so invoking
7447** sqlite3_unlock_notify() results in the unlock-notify callback being
7448** invoked immediately. If the application then re-attempts the "DROP TABLE"
7449** or "DROP INDEX" query, an infinite loop might be the result.
7451** One way around this problem is to check the extended error code returned
7452** by an sqlite3_step() call. ^(If there is a blocking connection, then the
7453** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
7454** the special "DROP TABLE/INDEX" case, the extended error code is just
7457SQLITE_API int SQLITE_STDCALL sqlite3_unlock_notify(
7458  sqlite3 *pBlocked,                          /* Waiting connection */
7459  void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
7460  void *pNotifyArg                            /* Argument to pass to xNotify */
7465** CAPI3REF: String Comparison
7467** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
7468** and extensions to compare the contents of two buffers containing UTF-8
7469** strings in a case-independent fashion, using the same definition of "case
7470** independence" that SQLite uses internally when comparing identifiers.
7472SQLITE_API int SQLITE_STDCALL sqlite3_stricmp(const char *, const char *);
7473SQLITE_API int SQLITE_STDCALL sqlite3_strnicmp(const char *, const char *, int);
7476** CAPI3REF: String Globbing
7478** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches
7479** the glob pattern P, and it returns non-zero if string X does not match
7480** the glob pattern P.  ^The definition of glob pattern matching used in
7481** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
7482** SQL dialect used by SQLite.  ^The sqlite3_strglob(P,X) function is case
7483** sensitive.
7485** Note that this routine returns zero on a match and non-zero if the strings
7486** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
7488SQLITE_API int SQLITE_STDCALL sqlite3_strglob(const char *zGlob, const char *zStr);
7491** CAPI3REF: Error Logging Interface
7493** ^The [sqlite3_log()] interface writes a message into the [error log]
7494** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
7495** ^If logging is enabled, the zFormat string and subsequent arguments are
7496** used with [sqlite3_snprintf()] to generate the final output string.
7498** The sqlite3_log() interface is intended for use by extensions such as
7499** virtual tables, collating functions, and SQL functions.  While there is
7500** nothing to prevent an application from calling sqlite3_log(), doing so
7501** is considered bad form.
7503** The zFormat string must not be NULL.
7505** To avoid deadlocks and other threading problems, the sqlite3_log() routine
7506** will not use dynamically allocated memory.  The log message is stored in
7507** a fixed-length buffer on the stack.  If the log message is longer than
7508** a few hundred characters, it will be truncated to the length of the
7509** buffer.
7511SQLITE_API void SQLITE_CDECL sqlite3_log(int iErrCode, const char *zFormat, ...);
7514** CAPI3REF: Write-Ahead Log Commit Hook
7515** METHOD: sqlite3
7517** ^The [sqlite3_wal_hook()] function is used to register a callback that
7518** is invoked each time data is committed to a database in wal mode.
7520** ^(The callback is invoked by SQLite after the commit has taken place and
7521** the associated write-lock on the database released)^, so the implementation
7522** may read, write or [checkpoint] the database as required.
7524** ^The first parameter passed to the callback function when it is invoked
7525** is a copy of the third parameter passed to sqlite3_wal_hook() when
7526** registering the callback. ^The second is a copy of the database handle.
7527** ^The third parameter is the name of the database that was written to -
7528** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
7529** is the number of pages currently in the write-ahead log file,
7530** including those that were just committed.
7532** The callback function should normally return [SQLITE_OK].  ^If an error
7533** code is returned, that error will propagate back up through the
7534** SQLite code base to cause the statement that provoked the callback
7535** to report an error, though the commit will have still occurred. If the
7536** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
7537** that does not correspond to any valid SQLite error code, the results
7538** are undefined.
7540** A single database handle may have at most a single write-ahead log callback
7541** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
7542** previously registered write-ahead log callback. ^Note that the
7543** [sqlite3_wal_autocheckpoint()] interface and the
7544** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
7545** those overwrite any prior [sqlite3_wal_hook()] settings.
7547SQLITE_API void *SQLITE_STDCALL sqlite3_wal_hook(
7548  sqlite3*,
7549  int(*)(void *,sqlite3*,const char*,int),
7550  void*
7554** CAPI3REF: Configure an auto-checkpoint
7555** METHOD: sqlite3
7557** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
7558** [sqlite3_wal_hook()] that causes any database on [database connection] D
7559** to automatically [checkpoint]
7560** after committing a transaction if there are N or
7561** more frames in the [write-ahead log] file.  ^Passing zero or
7562** a negative value as the nFrame parameter disables automatic
7563** checkpoints entirely.
7565** ^The callback registered by this function replaces any existing callback
7566** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
7567** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
7568** configured by this function.
7570** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
7571** from SQL.
7573** ^Checkpoints initiated by this mechanism are
7574** [sqlite3_wal_checkpoint_v2|PASSIVE].
7576** ^Every new [database connection] defaults to having the auto-checkpoint
7577** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
7578** pages.  The use of this interface
7579** is only necessary if the default setting is found to be suboptimal
7580** for a particular application.
7582SQLITE_API int SQLITE_STDCALL sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
7585** CAPI3REF: Checkpoint a database
7586** METHOD: sqlite3
7588** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
7589** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
7591** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
7592** [write-ahead log] for database X on [database connection] D to be
7593** transferred into the database file and for the write-ahead log to
7594** be reset.  See the [checkpointing] do