1/******************************************************************************
2** This file is an amalgamation of many separate C source files from SQLite
3** version 3.8.6.  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.
9**
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.
19*/
20#define SQLITE_CORE 1
21#define SQLITE_AMALGAMATION 1
22#ifndef SQLITE_PRIVATE
23# define SQLITE_PRIVATE static
24#endif
25#ifndef SQLITE_API
26# define SQLITE_API
27#endif
28/************** Begin file sqliteInt.h ***************************************/
29/*
30** 2001 September 15
31**
32** The author disclaims copyright to this source code.  In place of
33** a legal notice, here is a blessing:
34**
35**    May you do good and not evil.
36**    May you find forgiveness for yourself and forgive others.
37**    May you share freely, never taking more than you give.
38**
39*************************************************************************
40** Internal interface definitions for SQLite.
41**
42*/
43#ifndef _SQLITEINT_H_
44#define _SQLITEINT_H_
45
46/*
47** These #defines should enable >2GB file support on POSIX if the
48** underlying operating system supports it.  If the OS lacks
49** large file support, or if the OS is windows, these should be no-ops.
50**
51** Ticket #2739:  The _LARGEFILE_SOURCE macro must appear before any
52** system #includes.  Hence, this block of code must be the very first
53** code in all source files.
54**
55** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch
56** on the compiler command line.  This is necessary if you are compiling
57** on a recent machine (ex: Red Hat 7.2) but you want your code to work
58** on an older machine (ex: Red Hat 6.0).  If you compile on Red Hat 7.2
59** without this option, LFS is enable.  But LFS does not exist in the kernel
60** in Red Hat 6.0, so the code won't work.  Hence, for maximum binary
61** portability you should omit LFS.
62**
63** The previous paragraph was written in 2005.  (This paragraph is written
64** on 2008-11-28.) These days, all Linux kernels support large files, so
65** you should probably leave LFS enabled.  But some embedded platforms might
66** lack LFS in which case the SQLITE_DISABLE_LFS macro might still be useful.
67**
68** Similar is true for Mac OS X.  LFS is only supported on Mac OS X 9 and later.
69*/
70#ifndef SQLITE_DISABLE_LFS
71# define _LARGE_FILE       1
72# ifndef _FILE_OFFSET_BITS
73#   define _FILE_OFFSET_BITS 64
74# endif
75# define _LARGEFILE_SOURCE 1
76#endif
77
78/*
79** For MinGW, check to see if we can include the header file containing its
80** version information, among other things.  Normally, this internal MinGW
81** header file would [only] be included automatically by other MinGW header
82** files; however, the contained version information is now required by this
83** header file to work around binary compatibility issues (see below) and
84** this is the only known way to reliably obtain it.  This entire #if block
85** would be completely unnecessary if there was any other way of detecting
86** MinGW via their preprocessor (e.g. if they customized their GCC to define
87** some MinGW-specific macros).  When compiling for MinGW, either the
88** _HAVE_MINGW_H or _HAVE__MINGW_H (note the extra underscore) macro must be
89** defined; otherwise, detection of conditions specific to MinGW will be
90** disabled.
91*/
92#if defined(_HAVE_MINGW_H)
93# include "mingw.h"
94#elif defined(_HAVE__MINGW_H)
95# include "_mingw.h"
96#endif
97
98/*
99** For MinGW version 4.x (and higher), check to see if the _USE_32BIT_TIME_T
100** define is required to maintain binary compatibility with the MSVC runtime
101** library in use (e.g. for Windows XP).
102*/
103#if !defined(_USE_32BIT_TIME_T) && !defined(_USE_64BIT_TIME_T) && \
104    defined(_WIN32) && !defined(_WIN64) && \
105    defined(__MINGW_MAJOR_VERSION) && __MINGW_MAJOR_VERSION >= 4 && \
106    defined(__MSVCRT__)
107# define _USE_32BIT_TIME_T
108#endif
109
110/* The public SQLite interface.  The _FILE_OFFSET_BITS macro must appear
111** first in QNX.  Also, the _USE_32BIT_TIME_T macro must appear first for
112** MinGW.
113*/
114/************** Include sqlite3.h in the middle of sqliteInt.h ***************/
115/************** Begin file sqlite3.h *****************************************/
116/*
117** 2001 September 15
118**
119** The author disclaims copyright to this source code.  In place of
120** a legal notice, here is a blessing:
121**
122**    May you do good and not evil.
123**    May you find forgiveness for yourself and forgive others.
124**    May you share freely, never taking more than you give.
125**
126*************************************************************************
127** This header file defines the interface that the SQLite library
128** presents to client programs.  If a C-function, structure, datatype,
129** or constant definition does not appear in this file, then it is
130** not a published API of SQLite, is subject to change without
131** notice, and should not be referenced by programs that use SQLite.
132**
133** Some of the definitions that are in this file are marked as
134** "experimental".  Experimental interfaces are normally new
135** features recently added to SQLite.  We do not anticipate changes
136** to experimental interfaces but reserve the right to make minor changes
137** if experience from use "in the wild" suggest such changes are prudent.
138**
139** The official C-language API documentation for SQLite is derived
140** from comments in this file.  This file is the authoritative source
141** on how SQLite interfaces are suppose to operate.
142**
143** The name of this file under configuration management is "sqlite.h.in".
144** The makefile makes some minor changes to this file (such as inserting
145** the version number) and changes its name to "sqlite3.h" as
146** part of the build process.
147*/
148#ifndef _SQLITE3_H_
149#define _SQLITE3_H_
150#include <stdarg.h>     /* Needed for the definition of va_list */
151
152/*
153** Make sure we can call this stuff from C++.
154*/
155#if 0
156extern "C" {
157#endif
158
159
160/*
161** Add the ability to override 'extern'
162*/
163#ifndef SQLITE_EXTERN
164# define SQLITE_EXTERN extern
165#endif
166
167#ifndef SQLITE_API
168# define SQLITE_API
169#endif
170
171
172/*
173** These no-op macros are used in front of interfaces to mark those
174** interfaces as either deprecated or experimental.  New applications
175** should not use deprecated interfaces - they are support for backwards
176** compatibility only.  Application writers should be aware that
177** experimental interfaces are subject to change in point releases.
178**
179** These macros used to resolve to various kinds of compiler magic that
180** would generate warning messages when they were used.  But that
181** compiler magic ended up generating such a flurry of bug reports
182** that we have taken it all out and gone back to using simple
183** noop macros.
184*/
185#define SQLITE_DEPRECATED
186#define SQLITE_EXPERIMENTAL
187
188/*
189** Ensure these symbols were not defined by some previous header file.
190*/
191#ifdef SQLITE_VERSION
192# undef SQLITE_VERSION
193#endif
194#ifdef SQLITE_VERSION_NUMBER
195# undef SQLITE_VERSION_NUMBER
196#endif
197
198/*
199** CAPI3REF: Compile-Time Library Version Numbers
200**
201** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
202** evaluates to a string literal that is the SQLite version in the
203** format "X.Y.Z" where X is the major version number (always 3 for
204** SQLite3) and Y is the minor version number and Z is the release number.)^
205** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
206** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
207** numbers used in [SQLITE_VERSION].)^
208** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
209** be larger than the release from which it is derived.  Either Y will
210** be held constant and Z will be incremented or else Y will be incremented
211** and Z will be reset to zero.
212**
213** Since version 3.6.18, SQLite source code has been stored in the
214** <a href="http://www.fossil-scm.org/">Fossil configuration management
215** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
216** a string which identifies a particular check-in of SQLite
217** within its configuration management system.  ^The SQLITE_SOURCE_ID
218** string contains the date and time of the check-in (UTC) and an SHA1
219** hash of the entire source tree.
220**
221** See also: [sqlite3_libversion()],
222** [sqlite3_libversion_number()], [sqlite3_sourceid()],
223** [sqlite_version()] and [sqlite_source_id()].
224*/
225#define SQLITE_VERSION        "3.8.6"
226#define SQLITE_VERSION_NUMBER 3008006
227#define SQLITE_SOURCE_ID      "2014-08-15 11:46:33 9491ba7d738528f168657adb43a198238abde19e"
228
229/*
230** CAPI3REF: Run-Time Library Version Numbers
231** KEYWORDS: sqlite3_version, sqlite3_sourceid
232**
233** These interfaces provide the same information as the [SQLITE_VERSION],
234** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
235** but are associated with the library instead of the header file.  ^(Cautious
236** programmers might include assert() statements in their application to
237** verify that values returned by these interfaces match the macros in
238** the header, and thus insure that the application is
239** compiled with matching library and header files.
240**
241** <blockquote><pre>
242** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
243** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
244** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
245** </pre></blockquote>)^
246**
247** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
248** macro.  ^The sqlite3_libversion() function returns a pointer to the
249** to the sqlite3_version[] string constant.  The sqlite3_libversion()
250** function is provided for use in DLLs since DLL users usually do not have
251** direct access to string constants within the DLL.  ^The
252** sqlite3_libversion_number() function returns an integer equal to
253** [SQLITE_VERSION_NUMBER].  ^The sqlite3_sourceid() function returns
254** a pointer to a string constant whose value is the same as the
255** [SQLITE_SOURCE_ID] C preprocessor macro.
256**
257** See also: [sqlite_version()] and [sqlite_source_id()].
258*/
259SQLITE_API const char sqlite3_version[] = SQLITE_VERSION;
260SQLITE_API const char *sqlite3_libversion(void);
261SQLITE_API const char *sqlite3_sourceid(void);
262SQLITE_API int sqlite3_libversion_number(void);
263
264/*
265** CAPI3REF: Run-Time Library Compilation Options Diagnostics
266**
267** ^The sqlite3_compileoption_used() function returns 0 or 1
268** indicating whether the specified option was defined at
269** compile time.  ^The SQLITE_ prefix may be omitted from the
270** option name passed to sqlite3_compileoption_used().
271**
272** ^The sqlite3_compileoption_get() function allows iterating
273** over the list of options that were defined at compile time by
274** returning the N-th compile time option string.  ^If N is out of range,
275** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_
276** prefix is omitted from any strings returned by
277** sqlite3_compileoption_get().
278**
279** ^Support for the diagnostic functions sqlite3_compileoption_used()
280** and sqlite3_compileoption_get() may be omitted by specifying the
281** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
282**
283** See also: SQL functions [sqlite_compileoption_used()] and
284** [sqlite_compileoption_get()] and the [compile_options pragma].
285*/
286#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
287SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
288SQLITE_API const char *sqlite3_compileoption_get(int N);
289#endif
290
291/*
292** CAPI3REF: Test To See If The Library Is Threadsafe
293**
294** ^The sqlite3_threadsafe() function returns zero if and only if
295** SQLite was compiled with mutexing code omitted due to the
296** [SQLITE_THREADSAFE] compile-time option being set to 0.
297**
298** SQLite can be compiled with or without mutexes.  When
299** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
300** are enabled and SQLite is threadsafe.  When the
301** [SQLITE_THREADSAFE] macro is 0,
302** the mutexes are omitted.  Without the mutexes, it is not safe
303** to use SQLite concurrently from more than one thread.
304**
305** Enabling mutexes incurs a measurable performance penalty.
306** So if speed is of utmost importance, it makes sense to disable
307** the mutexes.  But for maximum safety, mutexes should be enabled.
308** ^The default behavior is for mutexes to be enabled.
309**
310** This interface can be used by an application to make sure that the
311** version of SQLite that it is linking against was compiled with
312** the desired setting of the [SQLITE_THREADSAFE] macro.
313**
314** This interface only reports on the compile-time mutex setting
315** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
316** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
317** can be fully or partially disabled using a call to [sqlite3_config()]
318** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
319** or [SQLITE_CONFIG_MUTEX].  ^(The return value of the
320** sqlite3_threadsafe() function shows only the compile-time setting of
321** thread safety, not any run-time changes to that setting made by
322** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
323** is unchanged by calls to sqlite3_config().)^
324**
325** See the [threading mode] documentation for additional information.
326*/
327SQLITE_API int sqlite3_threadsafe(void);
328
329/*
330** CAPI3REF: Database Connection Handle
331** KEYWORDS: {database connection} {database connections}
332**
333** Each open SQLite database is represented by a pointer to an instance of
334** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
335** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
336** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
337** and [sqlite3_close_v2()] are its destructors.  There are many other
338** interfaces (such as
339** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
340** [sqlite3_busy_timeout()] to name but three) that are methods on an
341** sqlite3 object.
342*/
343typedef struct sqlite3 sqlite3;
344
345/*
346** CAPI3REF: 64-Bit Integer Types
347** KEYWORDS: sqlite_int64 sqlite_uint64
348**
349** Because there is no cross-platform way to specify 64-bit integer types
350** SQLite includes typedefs for 64-bit signed and unsigned integers.
351**
352** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
353** The sqlite_int64 and sqlite_uint64 types are supported for backwards
354** compatibility only.
355**
356** ^The sqlite3_int64 and sqlite_int64 types can store integer values
357** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
358** sqlite3_uint64 and sqlite_uint64 types can store integer values
359** between 0 and +18446744073709551615 inclusive.
360*/
361#ifdef SQLITE_INT64_TYPE
362  typedef SQLITE_INT64_TYPE sqlite_int64;
363  typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
364#elif defined(_MSC_VER) || defined(__BORLANDC__)
365  typedef __int64 sqlite_int64;
366  typedef unsigned __int64 sqlite_uint64;
367#else
368  typedef long long int sqlite_int64;
369  typedef unsigned long long int sqlite_uint64;
370#endif
371typedef sqlite_int64 sqlite3_int64;
372typedef sqlite_uint64 sqlite3_uint64;
373
374/*
375** If compiling for a processor that lacks floating point support,
376** substitute integer for floating-point.
377*/
378#ifdef SQLITE_OMIT_FLOATING_POINT
379# define double sqlite3_int64
380#endif
381
382/*
383** CAPI3REF: Closing A Database Connection
384**
385** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
386** for the [sqlite3] object.
387** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
388** the [sqlite3] object is successfully destroyed and all associated
389** resources are deallocated.
390**
391** ^If the database connection is associated with unfinalized prepared
392** statements or unfinished sqlite3_backup objects then sqlite3_close()
393** will leave the database connection open and return [SQLITE_BUSY].
394** ^If sqlite3_close_v2() is called with unfinalized prepared statements
395** and/or unfinished sqlite3_backups, then the database connection becomes
396** an unusable "zombie" which will automatically be deallocated when the
397** last prepared statement is finalized or the last sqlite3_backup is
398** finished.  The sqlite3_close_v2() interface is intended for use with
399** host languages that are garbage collected, and where the order in which
400** destructors are called is arbitrary.
401**
402** Applications should [sqlite3_finalize | finalize] all [prepared statements],
403** [sqlite3_blob_close | close] all [BLOB handles], and
404** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
405** with the [sqlite3] object prior to attempting to close the object.  ^If
406** sqlite3_close_v2() is called on a [database connection] that still has
407** outstanding [prepared statements], [BLOB handles], and/or
408** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
409** of resources is deferred until all [prepared statements], [BLOB handles],
410** and [sqlite3_backup] objects are also destroyed.
411**
412** ^If an [sqlite3] object is destroyed while a transaction is open,
413** the transaction is automatically rolled back.
414**
415** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
416** must be either a NULL
417** pointer or an [sqlite3] object pointer obtained
418** from [sqlite3_open()], [sqlite3_open16()], or
419** [sqlite3_open_v2()], and not previously closed.
420** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
421** argument is a harmless no-op.
422*/
423SQLITE_API int sqlite3_close(sqlite3*);
424SQLITE_API int sqlite3_close_v2(sqlite3*);
425
426/*
427** The type for a callback function.
428** This is legacy and deprecated.  It is included for historical
429** compatibility and is not documented.
430*/
431typedef int (*sqlite3_callback)(void*,int,char**, char**);
432
433/*
434** CAPI3REF: One-Step Query Execution Interface
435**
436** The sqlite3_exec() interface is a convenience wrapper around
437** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
438** that allows an application to run multiple statements of SQL
439** without having to use a lot of C code.
440**
441** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
442** semicolon-separate SQL statements passed into its 2nd argument,
443** in the context of the [database connection] passed in as its 1st
444** argument.  ^If the callback function of the 3rd argument to
445** sqlite3_exec() is not NULL, then it is invoked for each result row
446** coming out of the evaluated SQL statements.  ^The 4th argument to
447** sqlite3_exec() is relayed through to the 1st argument of each
448** callback invocation.  ^If the callback pointer to sqlite3_exec()
449** is NULL, then no callback is ever invoked and result rows are
450** ignored.
451**
452** ^If an error occurs while evaluating the SQL statements passed into
453** sqlite3_exec(), then execution of the current statement stops and
454** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
455** is not NULL then any error message is written into memory obtained
456** from [sqlite3_malloc()] and passed back through the 5th parameter.
457** To avoid memory leaks, the application should invoke [sqlite3_free()]
458** on error message strings returned through the 5th parameter of
459** of sqlite3_exec() after the error message string is no longer needed.
460** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
461** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
462** NULL before returning.
463**
464** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
465** routine returns SQLITE_ABORT without invoking the callback again and
466** without running any subsequent SQL statements.
467**
468** ^The 2nd argument to the sqlite3_exec() callback function is the
469** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
470** callback is an array of pointers to strings obtained as if from
471** [sqlite3_column_text()], one for each column.  ^If an element of a
472** result row is NULL then the corresponding string pointer for the
473** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
474** sqlite3_exec() callback is an array of pointers to strings where each
475** entry represents the name of corresponding result column as obtained
476** from [sqlite3_column_name()].
477**
478** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
479** to an empty string, or a pointer that contains only whitespace and/or
480** SQL comments, then no SQL statements are evaluated and the database
481** is not changed.
482**
483** Restrictions:
484**
485** <ul>
486** <li> The application must insure that the 1st parameter to sqlite3_exec()
487**      is a valid and open [database connection].
488** <li> The application must not close the [database connection] specified by
489**      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
490** <li> The application must not modify the SQL statement text passed into
491**      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
492** </ul>
493*/
494SQLITE_API int sqlite3_exec(
495  sqlite3*,                                  /* An open database */
496  const char *sql,                           /* SQL to be evaluated */
497  int (*callback)(void*,int,char**,char**),  /* Callback function */
498  void *,                                    /* 1st argument to callback */
499  char **errmsg                              /* Error msg written here */
500);
501
502/*
503** CAPI3REF: Result Codes
504** KEYWORDS: {result code definitions}
505**
506** Many SQLite functions return an integer result code from the set shown
507** here in order to indicate success or failure.
508**
509** New error codes may be added in future versions of SQLite.
510**
511** See also: [extended result code definitions]
512*/
513#define SQLITE_OK           0   /* Successful result */
514/* beginning-of-error-codes */
515#define SQLITE_ERROR        1   /* SQL error or missing database */
516#define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
517#define SQLITE_PERM         3   /* Access permission denied */
518#define SQLITE_ABORT        4   /* Callback routine requested an abort */
519#define SQLITE_BUSY         5   /* The database file is locked */
520#define SQLITE_LOCKED       6   /* A table in the database is locked */
521#define SQLITE_NOMEM        7   /* A malloc() failed */
522#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
523#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
524#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
525#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
526#define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
527#define SQLITE_FULL        13   /* Insertion failed because database is full */
528#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
529#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
530#define SQLITE_EMPTY       16   /* Database is empty */
531#define SQLITE_SCHEMA      17   /* The database schema changed */
532#define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
533#define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
534#define SQLITE_MISMATCH    20   /* Data type mismatch */
535#define SQLITE_MISUSE      21   /* Library used incorrectly */
536#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
537#define SQLITE_AUTH        23   /* Authorization denied */
538#define SQLITE_FORMAT      24   /* Auxiliary database format error */
539#define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
540#define SQLITE_NOTADB      26   /* File opened that is not a database file */
541#define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
542#define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
543#define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
544#define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
545/* end-of-error-codes */
546
547/*
548** CAPI3REF: Extended Result Codes
549** KEYWORDS: {extended result code definitions}
550**
551** In its default configuration, SQLite API routines return one of 30 integer
552** [result codes].  However, experience has shown that many of
553** these result codes are too coarse-grained.  They do not provide as
554** much information about problems as programmers might like.  In an effort to
555** address this, newer versions of SQLite (version 3.3.8 and later) include
556** support for additional result codes that provide more detailed information
557** about errors. These [extended result codes] are enabled or disabled
558** on a per database connection basis using the
559** [sqlite3_extended_result_codes()] API.  Or, the extended code for
560** the most recent error can be obtained using
561** [sqlite3_extended_errcode()].
562*/
563#define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
564#define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
565#define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
566#define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
567#define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
568#define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
569#define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
570#define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
571#define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
572#define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
573#define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
574#define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
575#define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
576#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
577#define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
578#define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
579#define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
580#define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
581#define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
582#define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
583#define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
584#define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
585#define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
586#define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
587#define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
588#define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
589#define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
590#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
591#define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
592#define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
593#define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
594#define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
595#define SQLITE_CANTOPEN_CONVPATH       (SQLITE_CANTOPEN | (4<<8))
596#define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
597#define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
598#define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
599#define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
600#define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
601#define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
602#define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
603#define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
604#define SQLITE_CONSTRAINT_FOREIGNKEY   (SQLITE_CONSTRAINT | (3<<8))
605#define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
606#define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
607#define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
608#define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
609#define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
610#define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
611#define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
612#define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
613#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
614#define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
615
616/*
617** CAPI3REF: Flags For File Open Operations
618**
619** These bit values are intended for use in the
620** 3rd parameter to the [sqlite3_open_v2()] interface and
621** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
622*/
623#define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
624#define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
625#define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
626#define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
627#define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
628#define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
629#define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
630#define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
631#define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
632#define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
633#define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
634#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
635#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
636#define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
637#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
638#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
639#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
640#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
641#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
642#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
643
644/* Reserved:                         0x00F00000 */
645
646/*
647** CAPI3REF: Device Characteristics
648**
649** The xDeviceCharacteristics method of the [sqlite3_io_methods]
650** object returns an integer which is a vector of these
651** bit values expressing I/O characteristics of the mass storage
652** device that holds the file that the [sqlite3_io_methods]
653** refers to.
654**
655** The SQLITE_IOCAP_ATOMIC property means that all writes of
656** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
657** mean that writes of blocks that are nnn bytes in size and
658** are aligned to an address which is an integer multiple of
659** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
660** that when data is appended to a file, the data is appended
661** first then the size of the file is extended, never the other
662** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
663** information is written to disk in the same order as calls
664** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
665** after reboot following a crash or power loss, the only bytes in a
666** file that were written at the application level might have changed
667** and that adjacent bytes, even bytes within the same sector are
668** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
669** flag indicate that a file cannot be deleted when open.  The
670** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
671** read-only media and cannot be changed even by processes with
672** elevated privileges.
673*/
674#define SQLITE_IOCAP_ATOMIC                 0x00000001
675#define SQLITE_IOCAP_ATOMIC512              0x00000002
676#define SQLITE_IOCAP_ATOMIC1K               0x00000004
677#define SQLITE_IOCAP_ATOMIC2K               0x00000008
678#define SQLITE_IOCAP_ATOMIC4K               0x00000010
679#define SQLITE_IOCAP_ATOMIC8K               0x00000020
680#define SQLITE_IOCAP_ATOMIC16K              0x00000040
681#define SQLITE_IOCAP_ATOMIC32K              0x00000080
682#define SQLITE_IOCAP_ATOMIC64K              0x00000100
683#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
684#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
685#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
686#define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
687#define SQLITE_IOCAP_IMMUTABLE              0x00002000
688
689/*
690** CAPI3REF: File Locking Levels
691**
692** SQLite uses one of these integer values as the second
693** argument to calls it makes to the xLock() and xUnlock() methods
694** of an [sqlite3_io_methods] object.
695*/
696#define SQLITE_LOCK_NONE          0
697#define SQLITE_LOCK_SHARED        1
698#define SQLITE_LOCK_RESERVED      2
699#define SQLITE_LOCK_PENDING       3
700#define SQLITE_LOCK_EXCLUSIVE     4
701
702/*
703** CAPI3REF: Synchronization Type Flags
704**
705** When SQLite invokes the xSync() method of an
706** [sqlite3_io_methods] object it uses a combination of
707** these integer values as the second argument.
708**
709** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
710** sync operation only needs to flush data to mass storage.  Inode
711** information need not be flushed. If the lower four bits of the flag
712** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
713** If the lower four bits equal SQLITE_SYNC_FULL, that means
714** to use Mac OS X style fullsync instead of fsync().
715**
716** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
717** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
718** settings.  The [synchronous pragma] determines when calls to the
719** xSync VFS method occur and applies uniformly across all platforms.
720** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
721** energetic or rigorous or forceful the sync operations are and
722** only make a difference on Mac OSX for the default SQLite code.
723** (Third-party VFS implementations might also make the distinction
724** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
725** operating systems natively supported by SQLite, only Mac OSX
726** cares about the difference.)
727*/
728#define SQLITE_SYNC_NORMAL        0x00002
729#define SQLITE_SYNC_FULL          0x00003
730#define SQLITE_SYNC_DATAONLY      0x00010
731
732/*
733** CAPI3REF: OS Interface Open File Handle
734**
735** An [sqlite3_file] object represents an open file in the
736** [sqlite3_vfs | OS interface layer].  Individual OS interface
737** implementations will
738** want to subclass this object by appending additional fields
739** for their own use.  The pMethods entry is a pointer to an
740** [sqlite3_io_methods] object that defines methods for performing
741** I/O operations on the open file.
742*/
743typedef struct sqlite3_file sqlite3_file;
744struct sqlite3_file {
745  const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
746};
747
748/*
749** CAPI3REF: OS Interface File Virtual Methods Object
750**
751** Every file opened by the [sqlite3_vfs.xOpen] method populates an
752** [sqlite3_file] object (or, more commonly, a subclass of the
753** [sqlite3_file] object) with a pointer to an instance of this object.
754** This object defines the methods used to perform various operations
755** against the open file represented by the [sqlite3_file] object.
756**
757** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
758** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
759** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
760** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
761** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
762** to NULL.
763**
764** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
765** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
766** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
767** flag may be ORed in to indicate that only the data of the file
768** and not its inode needs to be synced.
769**
770** The integer values to xLock() and xUnlock() are one of
771** <ul>
772** <li> [SQLITE_LOCK_NONE],
773** <li> [SQLITE_LOCK_SHARED],
774** <li> [SQLITE_LOCK_RESERVED],
775** <li> [SQLITE_LOCK_PENDING], or
776** <li> [SQLITE_LOCK_EXCLUSIVE].
777** </ul>
778** xLock() increases the lock. xUnlock() decreases the lock.
779** The xCheckReservedLock() method checks whether any database connection,
780** either in this process or in some other process, is holding a RESERVED,
781** PENDING, or EXCLUSIVE lock on the file.  It returns true
782** if such a lock exists and false otherwise.
783**
784** The xFileControl() method is a generic interface that allows custom
785** VFS implementations to directly control an open file using the
786** [sqlite3_file_control()] interface.  The second "op" argument is an
787** integer opcode.  The third argument is a generic pointer intended to
788** point to a structure that may contain arguments or space in which to
789** write return values.  Potential uses for xFileControl() might be
790** functions to enable blocking locks with timeouts, to change the
791** locking strategy (for example to use dot-file locks), to inquire
792** about the status of a lock, or to break stale locks.  The SQLite
793** core reserves all opcodes less than 100 for its own use.
794** A [file control opcodes | list of opcodes] less than 100 is available.
795** Applications that define a custom xFileControl method should use opcodes
796** greater than 100 to avoid conflicts.  VFS implementations should
797** return [SQLITE_NOTFOUND] for file control opcodes that they do not
798** recognize.
799**
800** The xSectorSize() method returns the sector size of the
801** device that underlies the file.  The sector size is the
802** minimum write that can be performed without disturbing
803** other bytes in the file.  The xDeviceCharacteristics()
804** method returns a bit vector describing behaviors of the
805** underlying device:
806**
807** <ul>
808** <li> [SQLITE_IOCAP_ATOMIC]
809** <li> [SQLITE_IOCAP_ATOMIC512]
810** <li> [SQLITE_IOCAP_ATOMIC1K]
811** <li> [SQLITE_IOCAP_ATOMIC2K]
812** <li> [SQLITE_IOCAP_ATOMIC4K]
813** <li> [SQLITE_IOCAP_ATOMIC8K]
814** <li> [SQLITE_IOCAP_ATOMIC16K]
815** <li> [SQLITE_IOCAP_ATOMIC32K]
816** <li> [SQLITE_IOCAP_ATOMIC64K]
817** <li> [SQLITE_IOCAP_SAFE_APPEND]
818** <li> [SQLITE_IOCAP_SEQUENTIAL]
819** </ul>
820**
821** The SQLITE_IOCAP_ATOMIC property means that all writes of
822** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
823** mean that writes of blocks that are nnn bytes in size and
824** are aligned to an address which is an integer multiple of
825** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
826** that when data is appended to a file, the data is appended
827** first then the size of the file is extended, never the other
828** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
829** information is written to disk in the same order as calls
830** to xWrite().
831**
832** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
833** in the unread portions of the buffer with zeros.  A VFS that
834** fails to zero-fill short reads might seem to work.  However,
835** failure to zero-fill short reads will eventually lead to
836** database corruption.
837*/
838typedef struct sqlite3_io_methods sqlite3_io_methods;
839struct sqlite3_io_methods {
840  int iVersion;
841  int (*xClose)(sqlite3_file*);
842  int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
843  int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
844  int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
845  int (*xSync)(sqlite3_file*, int flags);
846  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
847  int (*xLock)(sqlite3_file*, int);
848  int (*xUnlock)(sqlite3_file*, int);
849  int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
850  int (*xFileControl)(sqlite3_file*, int op, void *pArg);
851  int (*xSectorSize)(sqlite3_file*);
852  int (*xDeviceCharacteristics)(sqlite3_file*);
853  /* Methods above are valid for version 1 */
854  int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
855  int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
856  void (*xShmBarrier)(sqlite3_file*);
857  int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
858  /* Methods above are valid for version 2 */
859  int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
860  int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
861  /* Methods above are valid for version 3 */
862  /* Additional methods may be added in future releases */
863};
864
865/*
866** CAPI3REF: Standard File Control Opcodes
867** KEYWORDS: {file control opcodes} {file control opcode}
868**
869** These integer constants are opcodes for the xFileControl method
870** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
871** interface.
872**
873** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
874** opcode causes the xFileControl method to write the current state of
875** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
876** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
877** into an integer that the pArg argument points to. This capability
878** is used during testing and only needs to be supported when SQLITE_TEST
879** is defined.
880** <ul>
881** <li>[[SQLITE_FCNTL_SIZE_HINT]]
882** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
883** layer a hint of how large the database file will grow to be during the
884** current transaction.  This hint is not guaranteed to be accurate but it
885** is often close.  The underlying VFS might choose to preallocate database
886** file space based on this hint in order to help writes to the database
887** file run faster.
888**
889** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
890** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
891** extends and truncates the database file in chunks of a size specified
892** by the user. The fourth argument to [sqlite3_file_control()] should
893** point to an integer (type int) containing the new chunk-size to use
894** for the nominated database. Allocating database file space in large
895** chunks (say 1MB at a time), may reduce file-system fragmentation and
896** improve performance on some systems.
897**
898** <li>[[SQLITE_FCNTL_FILE_POINTER]]
899** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
900** to the [sqlite3_file] object associated with a particular database
901** connection.  See the [sqlite3_file_control()] documentation for
902** additional information.
903**
904** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
905** No longer in use.
906**
907** <li>[[SQLITE_FCNTL_SYNC]]
908** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
909** sent to the VFS immediately before the xSync method is invoked on a
910** database file descriptor. Or, if the xSync method is not invoked
911** because the user has configured SQLite with
912** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
913** of the xSync method. In most cases, the pointer argument passed with
914** this file-control is NULL. However, if the database file is being synced
915** as part of a multi-database commit, the argument points to a nul-terminated
916** string containing the transactions master-journal file name. VFSes that
917** do not need this signal should silently ignore this opcode. Applications
918** should not call [sqlite3_file_control()] with this opcode as doing so may
919** disrupt the operation of the specialized VFSes that do require it.
920**
921** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
922** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
923** and sent to the VFS after a transaction has been committed immediately
924** but before the database is unlocked. VFSes that do not need this signal
925** should silently ignore this opcode. Applications should not call
926** [sqlite3_file_control()] with this opcode as doing so may disrupt the
927** operation of the specialized VFSes that do require it.
928**
929** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
930** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
931** retry counts and intervals for certain disk I/O operations for the
932** windows [VFS] in order to provide robustness in the presence of
933** anti-virus programs.  By default, the windows VFS will retry file read,
934** file write, and file delete operations up to 10 times, with a delay
935** of 25 milliseconds before the first retry and with the delay increasing
936** by an additional 25 milliseconds with each subsequent retry.  This
937** opcode allows these two values (10 retries and 25 milliseconds of delay)
938** to be adjusted.  The values are changed for all database connections
939** within the same process.  The argument is a pointer to an array of two
940** integers where the first integer i the new retry count and the second
941** integer is the delay.  If either integer is negative, then the setting
942** is not changed but instead the prior value of that setting is written
943** into the array entry, allowing the current retry settings to be
944** interrogated.  The zDbName parameter is ignored.
945**
946** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
947** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
948** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
949** write ahead log and shared memory files used for transaction control
950** are automatically deleted when the latest connection to the database
951** closes.  Setting persistent WAL mode causes those files to persist after
952** close.  Persisting the files is useful when other processes that do not
953** have write permission on the directory containing the database file want
954** to read the database file, as the WAL and shared memory files must exist
955** in order for the database to be readable.  The fourth parameter to
956** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
957** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
958** WAL mode.  If the integer is -1, then it is overwritten with the current
959** WAL persistence setting.
960**
961** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
962** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
963** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
964** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
965** xDeviceCharacteristics methods. The fourth parameter to
966** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
967** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
968** mode.  If the integer is -1, then it is overwritten with the current
969** zero-damage mode setting.
970**
971** <li>[[SQLITE_FCNTL_OVERWRITE]]
972** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
973** a write transaction to indicate that, unless it is rolled back for some
974** reason, the entire database file will be overwritten by the current
975** transaction. This is used by VACUUM operations.
976**
977** <li>[[SQLITE_FCNTL_VFSNAME]]
978** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
979** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
980** final bottom-level VFS are written into memory obtained from
981** [sqlite3_malloc()] and the result is stored in the char* variable
982** that the fourth parameter of [sqlite3_file_control()] points to.
983** The caller is responsible for freeing the memory when done.  As with
984** all file-control actions, there is no guarantee that this will actually
985** do anything.  Callers should initialize the char* variable to a NULL
986** pointer in case this file-control is not implemented.  This file-control
987** is intended for diagnostic use only.
988**
989** <li>[[SQLITE_FCNTL_PRAGMA]]
990** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
991** file control is sent to the open [sqlite3_file] object corresponding
992** to the database file to which the pragma statement refers. ^The argument
993** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
994** pointers to strings (char**) in which the second element of the array
995** is the name of the pragma and the third element is the argument to the
996** pragma or NULL if the pragma has no argument.  ^The handler for an
997** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
998** of the char** argument point to a string obtained from [sqlite3_mprintf()]
999** or the equivalent and that string will become the result of the pragma or
1000** the error message if the pragma fails. ^If the
1001** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
1002** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
1003** file control returns [SQLITE_OK], then the parser assumes that the
1004** VFS has handled the PRAGMA itself and the parser generates a no-op
1005** prepared statement.  ^If the [SQLITE_FCNTL_PRAGMA] file control returns
1006** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
1007** that the VFS encountered an error while handling the [PRAGMA] and the
1008** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
1009** file control occurs at the beginning of pragma statement analysis and so
1010** it is able to override built-in [PRAGMA] statements.
1011**
1012** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
1013** ^The [SQLITE_FCNTL_BUSYHANDLER]
1014** file-control may be invoked by SQLite on the database file handle
1015** shortly after it is opened in order to provide a custom VFS with access
1016** to the connections busy-handler callback. The argument is of type (void **)
1017** - an array of two (void *) values. The first (void *) actually points
1018** to a function of type (int (*)(void *)). In order to invoke the connections
1019** busy-handler, this function should be invoked with the second (void *) in
1020** the array as the only argument. If it returns non-zero, then the operation
1021** should be retried. If it returns zero, the custom VFS should abandon the
1022** current operation.
1023**
1024** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
1025** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
1026** to have SQLite generate a
1027** temporary filename using the same algorithm that is followed to generate
1028** temporary filenames for TEMP tables and other internal uses.  The
1029** argument should be a char** which will be filled with the filename
1030** written into memory obtained from [sqlite3_malloc()].  The caller should
1031** invoke [sqlite3_free()] on the result to avoid a memory leak.
1032**
1033** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
1034** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
1035** maximum number of bytes that will be used for memory-mapped I/O.
1036** The argument is a pointer to a value of type sqlite3_int64 that
1037** is an advisory maximum number of bytes in the file to memory map.  The
1038** pointer is overwritten with the old value.  The limit is not changed if
1039** the value originally pointed to is negative, and so the current limit
1040** can be queried by passing in a pointer to a negative number.  This
1041** file-control is used internally to implement [PRAGMA mmap_size].
1042**
1043** <li>[[SQLITE_FCNTL_TRACE]]
1044** The [SQLITE_FCNTL_TRACE] file control provides advisory information
1045** to the VFS about what the higher layers of the SQLite stack are doing.
1046** This file control is used by some VFS activity tracing [shims].
1047** The argument is a zero-terminated string.  Higher layers in the
1048** SQLite stack may generate instances of this file control if
1049** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
1050**
1051** <li>[[SQLITE_FCNTL_HAS_MOVED]]
1052** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
1053** pointer to an integer and it writes a boolean into that integer depending
1054** on whether or not the file has been renamed, moved, or deleted since it
1055** was first opened.
1056**
1057** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
1058** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
1059** opcode causes the xFileControl method to swap the file handle with the one
1060** pointed to by the pArg argument.  This capability is used during testing
1061** and only needs to be supported when SQLITE_TEST is defined.
1062**
1063** </ul>
1064*/
1065#define SQLITE_FCNTL_LOCKSTATE               1
1066#define SQLITE_GET_LOCKPROXYFILE             2
1067#define SQLITE_SET_LOCKPROXYFILE             3
1068#define SQLITE_LAST_ERRNO                    4
1069#define SQLITE_FCNTL_SIZE_HINT               5
1070#define SQLITE_FCNTL_CHUNK_SIZE              6
1071#define SQLITE_FCNTL_FILE_POINTER            7
1072#define SQLITE_FCNTL_SYNC_OMITTED            8
1073#define SQLITE_FCNTL_WIN32_AV_RETRY          9
1074#define SQLITE_FCNTL_PERSIST_WAL            10
1075#define SQLITE_FCNTL_OVERWRITE              11
1076#define SQLITE_FCNTL_VFSNAME                12
1077#define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
1078#define SQLITE_FCNTL_PRAGMA                 14
1079#define SQLITE_FCNTL_BUSYHANDLER            15
1080#define SQLITE_FCNTL_TEMPFILENAME           16
1081#define SQLITE_FCNTL_MMAP_SIZE              18
1082#define SQLITE_FCNTL_TRACE                  19
1083#define SQLITE_FCNTL_HAS_MOVED              20
1084#define SQLITE_FCNTL_SYNC                   21
1085#define SQLITE_FCNTL_COMMIT_PHASETWO        22
1086#define SQLITE_FCNTL_WIN32_SET_HANDLE       23
1087
1088/*
1089** CAPI3REF: Mutex Handle
1090**
1091** The mutex module within SQLite defines [sqlite3_mutex] to be an
1092** abstract type for a mutex object.  The SQLite core never looks
1093** at the internal representation of an [sqlite3_mutex].  It only
1094** deals with pointers to the [sqlite3_mutex] object.
1095**
1096** Mutexes are created using [sqlite3_mutex_alloc()].
1097*/
1098typedef struct sqlite3_mutex sqlite3_mutex;
1099
1100/*
1101** CAPI3REF: OS Interface Object
1102**
1103** An instance of the sqlite3_vfs object defines the interface between
1104** the SQLite core and the underlying operating system.  The "vfs"
1105** in the name of the object stands for "virtual file system".  See
1106** the [VFS | VFS documentation] for further information.
1107**
1108** The value of the iVersion field is initially 1 but may be larger in
1109** future versions of SQLite.  Additional fields may be appended to this
1110** object when the iVersion value is increased.  Note that the structure
1111** of the sqlite3_vfs object changes in the transaction between
1112** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
1113** modified.
1114**
1115** The szOsFile field is the size of the subclassed [sqlite3_file]
1116** structure used by this VFS.  mxPathname is the maximum length of
1117** a pathname in this VFS.
1118**
1119** Registered sqlite3_vfs objects are kept on a linked list formed by
1120** the pNext pointer.  The [sqlite3_vfs_register()]
1121** and [sqlite3_vfs_unregister()] interfaces manage this list
1122** in a thread-safe way.  The [sqlite3_vfs_find()] interface
1123** searches the list.  Neither the application code nor the VFS
1124** implementation should use the pNext pointer.
1125**
1126** The pNext field is the only field in the sqlite3_vfs
1127** structure that SQLite will ever modify.  SQLite will only access
1128** or modify this field while holding a particular static mutex.
1129** The application should never modify anything within the sqlite3_vfs
1130** object once the object has been registered.
1131**
1132** The zName field holds the name of the VFS module.  The name must
1133** be unique across all VFS modules.
1134**
1135** [[sqlite3_vfs.xOpen]]
1136** ^SQLite guarantees that the zFilename parameter to xOpen
1137** is either a NULL pointer or string obtained
1138** from xFullPathname() with an optional suffix added.
1139** ^If a suffix is added to the zFilename parameter, it will
1140** consist of a single "-" character followed by no more than
1141** 11 alphanumeric and/or "-" characters.
1142** ^SQLite further guarantees that
1143** the string will be valid and unchanged until xClose() is
1144** called. Because of the previous sentence,
1145** the [sqlite3_file] can safely store a pointer to the
1146** filename if it needs to remember the filename for some reason.
1147** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1148** must invent its own temporary name for the file.  ^Whenever the
1149** xFilename parameter is NULL it will also be the case that the
1150** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1151**
1152** The flags argument to xOpen() includes all bits set in
1153** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
1154** or [sqlite3_open16()] is used, then flags includes at least
1155** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1156** If xOpen() opens a file read-only then it sets *pOutFlags to
1157** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
1158**
1159** ^(SQLite will also add one of the following flags to the xOpen()
1160** call, depending on the object being opened:
1161**
1162** <ul>
1163** <li>  [SQLITE_OPEN_MAIN_DB]
1164** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
1165** <li>  [SQLITE_OPEN_TEMP_DB]
1166** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
1167** <li>  [SQLITE_OPEN_TRANSIENT_DB]
1168** <li>  [SQLITE_OPEN_SUBJOURNAL]
1169** <li>  [SQLITE_OPEN_MASTER_JOURNAL]
1170** <li>  [SQLITE_OPEN_WAL]
1171** </ul>)^
1172**
1173** The file I/O implementation can use the object type flags to
1174** change the way it deals with files.  For example, an application
1175** that does not care about crash recovery or rollback might make
1176** the open of a journal file a no-op.  Writes to this journal would
1177** also be no-ops, and any attempt to read the journal would return
1178** SQLITE_IOERR.  Or the implementation might recognize that a database
1179** file will be doing page-aligned sector reads and writes in a random
1180** order and set up its I/O subsystem accordingly.
1181**
1182** SQLite might also add one of the following flags to the xOpen method:
1183**
1184** <ul>
1185** <li> [SQLITE_OPEN_DELETEONCLOSE]
1186** <li> [SQLITE_OPEN_EXCLUSIVE]
1187** </ul>
1188**
1189** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1190** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
1191** will be set for TEMP databases and their journals, transient
1192** databases, and subjournals.
1193**
1194** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1195** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1196** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1197** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1198** SQLITE_OPEN_CREATE, is used to indicate that file should always
1199** be created, and that it is an error if it already exists.
1200** It is <i>not</i> used to indicate the file should be opened
1201** for exclusive access.
1202**
1203** ^At least szOsFile bytes of memory are allocated by SQLite
1204** to hold the  [sqlite3_file] structure passed as the third
1205** argument to xOpen.  The xOpen method does not have to
1206** allocate the structure; it should just fill it in.  Note that
1207** the xOpen method must set the sqlite3_file.pMethods to either
1208** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
1209** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
1210** element will be valid after xOpen returns regardless of the success
1211** or failure of the xOpen call.
1212**
1213** [[sqlite3_vfs.xAccess]]
1214** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1215** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1216** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1217** to test whether a file is at least readable.   The file can be a
1218** directory.
1219**
1220** ^SQLite will always allocate at least mxPathname+1 bytes for the
1221** output buffer xFullPathname.  The exact size of the output buffer
1222** is also passed as a parameter to both  methods. If the output buffer
1223** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1224** handled as a fatal error by SQLite, vfs implementations should endeavor
1225** to prevent this by setting mxPathname to a sufficiently large value.
1226**
1227** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1228** interfaces are not strictly a part of the filesystem, but they are
1229** included in the VFS structure for completeness.
1230** The xRandomness() function attempts to return nBytes bytes
1231** of good-quality randomness into zOut.  The return value is
1232** the actual number of bytes of randomness obtained.
1233** The xSleep() method causes the calling thread to sleep for at
1234** least the number of microseconds given.  ^The xCurrentTime()
1235** method returns a Julian Day Number for the current date and time as
1236** a floating point value.
1237** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1238** Day Number multiplied by 86400000 (the number of milliseconds in
1239** a 24-hour day).
1240** ^SQLite will use the xCurrentTimeInt64() method to get the current
1241** date and time if that method is available (if iVersion is 2 or
1242** greater and the function pointer is not NULL) and will fall back
1243** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1244**
1245** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1246** are not used by the SQLite core.  These optional interfaces are provided
1247** by some VFSes to facilitate testing of the VFS code. By overriding
1248** system calls with functions under its control, a test program can
1249** simulate faults and error conditions that would otherwise be difficult
1250** or impossible to induce.  The set of system calls that can be overridden
1251** varies from one VFS to another, and from one version of the same VFS to the
1252** next.  Applications that use these interfaces must be prepared for any
1253** or all of these interfaces to be NULL or for their behavior to change
1254** from one release to the next.  Applications must not attempt to access
1255** any of these methods if the iVersion of the VFS is less than 3.
1256*/
1257typedef struct sqlite3_vfs sqlite3_vfs;
1258typedef void (*sqlite3_syscall_ptr)(void);
1259struct sqlite3_vfs {
1260  int iVersion;            /* Structure version number (currently 3) */
1261  int szOsFile;            /* Size of subclassed sqlite3_file */
1262  int mxPathname;          /* Maximum file pathname length */
1263  sqlite3_vfs *pNext;      /* Next registered VFS */
1264  const char *zName;       /* Name of this virtual file system */
1265  void *pAppData;          /* Pointer to application-specific data */
1266  int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1267               int flags, int *pOutFlags);
1268  int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1269  int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1270  int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1271  void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1272  void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1273  void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1274  void (*xDlClose)(sqlite3_vfs*, void*);
1275  int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1276  int (*xSleep)(sqlite3_vfs*, int microseconds);
1277  int (*xCurrentTime)(sqlite3_vfs*, double*);
1278  int (*xGetLastError)(sqlite3_vfs*, int, char *);
1279  /*
1280  ** The methods above are in version 1 of the sqlite_vfs object
1281  ** definition.  Those that follow are added in version 2 or later
1282  */
1283  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1284  /*
1285  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1286  ** Those below are for version 3 and greater.
1287  */
1288  int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1289  sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1290  const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1291  /*
1292  ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1293  ** New fields may be appended in figure versions.  The iVersion
1294  ** value will increment whenever this happens.
1295  */
1296};
1297
1298/*
1299** CAPI3REF: Flags for the xAccess VFS method
1300**
1301** These integer constants can be used as the third parameter to
1302** the xAccess method of an [sqlite3_vfs] object.  They determine
1303** what kind of permissions the xAccess method is looking for.
1304** With SQLITE_ACCESS_EXISTS, the xAccess method
1305** simply checks whether the file exists.
1306** With SQLITE_ACCESS_READWRITE, the xAccess method
1307** checks whether the named directory is both readable and writable
1308** (in other words, if files can be added, removed, and renamed within
1309** the directory).
1310** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1311** [temp_store_directory pragma], though this could change in a future
1312** release of SQLite.
1313** With SQLITE_ACCESS_READ, the xAccess method
1314** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
1315** currently unused, though it might be used in a future release of
1316** SQLite.
1317*/
1318#define SQLITE_ACCESS_EXISTS    0
1319#define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
1320#define SQLITE_ACCESS_READ      2   /* Unused */
1321
1322/*
1323** CAPI3REF: Flags for the xShmLock VFS method
1324**
1325** These integer constants define the various locking operations
1326** allowed by the xShmLock method of [sqlite3_io_methods].  The
1327** following are the only legal combinations of flags to the
1328** xShmLock method:
1329**
1330** <ul>
1331** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1332** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1333** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1334** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1335** </ul>
1336**
1337** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1338** was given no the corresponding lock.
1339**
1340** The xShmLock method can transition between unlocked and SHARED or
1341** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
1342** and EXCLUSIVE.
1343*/
1344#define SQLITE_SHM_UNLOCK       1
1345#define SQLITE_SHM_LOCK         2
1346#define SQLITE_SHM_SHARED       4
1347#define SQLITE_SHM_EXCLUSIVE    8
1348
1349/*
1350** CAPI3REF: Maximum xShmLock index
1351**
1352** The xShmLock method on [sqlite3_io_methods] may use values
1353** between 0 and this upper bound as its "offset" argument.
1354** The SQLite core will never attempt to acquire or release a
1355** lock outside of this range
1356*/
1357#define SQLITE_SHM_NLOCK        8
1358
1359
1360/*
1361** CAPI3REF: Initialize The SQLite Library
1362**
1363** ^The sqlite3_initialize() routine initializes the
1364** SQLite library.  ^The sqlite3_shutdown() routine
1365** deallocates any resources that were allocated by sqlite3_initialize().
1366** These routines are designed to aid in process initialization and
1367** shutdown on embedded systems.  Workstation applications using
1368** SQLite normally do not need to invoke either of these routines.
1369**
1370** A call to sqlite3_initialize() is an "effective" call if it is
1371** the first time sqlite3_initialize() is invoked during the lifetime of
1372** the process, or if it is the first time sqlite3_initialize() is invoked
1373** following a call to sqlite3_shutdown().  ^(Only an effective call
1374** of sqlite3_initialize() does any initialization.  All other calls
1375** are harmless no-ops.)^
1376**
1377** A call to sqlite3_shutdown() is an "effective" call if it is the first
1378** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
1379** an effective call to sqlite3_shutdown() does any deinitialization.
1380** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1381**
1382** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1383** is not.  The sqlite3_shutdown() interface must only be called from a
1384** single thread.  All open [database connections] must be closed and all
1385** other SQLite resources must be deallocated prior to invoking
1386** sqlite3_shutdown().
1387**
1388** Among other things, ^sqlite3_initialize() will invoke
1389** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
1390** will invoke sqlite3_os_end().
1391**
1392** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1393** ^If for some reason, sqlite3_initialize() is unable to initialize
1394** the library (perhaps it is unable to allocate a needed resource such
1395** as a mutex) it returns an [error code] other than [SQLITE_OK].
1396**
1397** ^The sqlite3_initialize() routine is called internally by many other
1398** SQLite interfaces so that an application usually does not need to
1399** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
1400** calls sqlite3_initialize() so the SQLite library will be automatically
1401** initialized when [sqlite3_open()] is called if it has not be initialized
1402** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1403** compile-time option, then the automatic calls to sqlite3_initialize()
1404** are omitted and the application must call sqlite3_initialize() directly
1405** prior to using any other SQLite interface.  For maximum portability,
1406** it is recommended that applications always invoke sqlite3_initialize()
1407** directly prior to using any other SQLite interface.  Future releases
1408** of SQLite may require this.  In other words, the behavior exhibited
1409** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1410** default behavior in some future release of SQLite.
1411**
1412** The sqlite3_os_init() routine does operating-system specific
1413** initialization of the SQLite library.  The sqlite3_os_end()
1414** routine undoes the effect of sqlite3_os_init().  Typical tasks
1415** performed by these routines include allocation or deallocation
1416** of static resources, initialization of global variables,
1417** setting up a default [sqlite3_vfs] module, or setting up
1418** a default configuration using [sqlite3_config()].
1419**
1420** The application should never invoke either sqlite3_os_init()
1421** or sqlite3_os_end() directly.  The application should only invoke
1422** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
1423** interface is called automatically by sqlite3_initialize() and
1424** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
1425** implementations for sqlite3_os_init() and sqlite3_os_end()
1426** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1427** When [custom builds | built for other platforms]
1428** (using the [SQLITE_OS_OTHER=1] compile-time
1429** option) the application must supply a suitable implementation for
1430** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
1431** implementation of sqlite3_os_init() or sqlite3_os_end()
1432** must return [SQLITE_OK] on success and some other [error code] upon
1433** failure.
1434*/
1435SQLITE_API int sqlite3_initialize(void);
1436SQLITE_API int sqlite3_shutdown(void);
1437SQLITE_API int sqlite3_os_init(void);
1438SQLITE_API int sqlite3_os_end(void);
1439
1440/*
1441** CAPI3REF: Configuring The SQLite Library
1442**
1443** The sqlite3_config() interface is used to make global configuration
1444** changes to SQLite in order to tune SQLite to the specific needs of
1445** the application.  The default configuration is recommended for most
1446** applications and so this routine is usually not necessary.  It is
1447** provided to support rare applications with unusual needs.
1448**
1449** The sqlite3_config() interface is not threadsafe.  The application
1450** must insure that no other SQLite interfaces are invoked by other
1451** threads while sqlite3_config() is running.  Furthermore, sqlite3_config()
1452** may only be invoked prior to library initialization using
1453** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1454** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1455** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1456** Note, however, that ^sqlite3_config() can be called as part of the
1457** implementation of an application-defined [sqlite3_os_init()].
1458**
1459** The first argument to sqlite3_config() is an integer
1460** [configuration option] that determines
1461** what property of SQLite is to be configured.  Subsequent arguments
1462** vary depending on the [configuration option]
1463** in the first argument.
1464**
1465** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1466** ^If the option is unknown or SQLite is unable to set the option
1467** then this routine returns a non-zero [error code].
1468*/
1469SQLITE_API int sqlite3_config(int, ...);
1470
1471/*
1472** CAPI3REF: Configure database connections
1473**
1474** The sqlite3_db_config() interface is used to make configuration
1475** changes to a [database connection].  The interface is similar to
1476** [sqlite3_config()] except that the changes apply to a single
1477** [database connection] (specified in the first argument).
1478**
1479** The second argument to sqlite3_db_config(D,V,...)  is the
1480** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1481** that indicates what aspect of the [database connection] is being configured.
1482** Subsequent arguments vary depending on the configuration verb.
1483**
1484** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1485** the call is considered successful.
1486*/
1487SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1488
1489/*
1490** CAPI3REF: Memory Allocation Routines
1491**
1492** An instance of this object defines the interface between SQLite
1493** and low-level memory allocation routines.
1494**
1495** This object is used in only one place in the SQLite interface.
1496** A pointer to an instance of this object is the argument to
1497** [sqlite3_config()] when the configuration option is
1498** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1499** By creating an instance of this object
1500** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1501** during configuration, an application can specify an alternative
1502** memory allocation subsystem for SQLite to use for all of its
1503** dynamic memory needs.
1504**
1505** Note that SQLite comes with several [built-in memory allocators]
1506** that are perfectly adequate for the overwhelming majority of applications
1507** and that this object is only useful to a tiny minority of applications
1508** with specialized memory allocation requirements.  This object is
1509** also used during testing of SQLite in order to specify an alternative
1510** memory allocator that simulates memory out-of-memory conditions in
1511** order to verify that SQLite recovers gracefully from such
1512** conditions.
1513**
1514** The xMalloc, xRealloc, and xFree methods must work like the
1515** malloc(), realloc() and free() functions from the standard C library.
1516** ^SQLite guarantees that the second argument to
1517** xRealloc is always a value returned by a prior call to xRoundup.
1518**
1519** xSize should return the allocated size of a memory allocation
1520** previously obtained from xMalloc or xRealloc.  The allocated size
1521** is always at least as big as the requested size but may be larger.
1522**
1523** The xRoundup method returns what would be the allocated size of
1524** a memory allocation given a particular requested size.  Most memory
1525** allocators round up memory allocations at least to the next multiple
1526** of 8.  Some allocators round up to a larger multiple or to a power of 2.
1527** Every memory allocation request coming in through [sqlite3_malloc()]
1528** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
1529** that causes the corresponding memory allocation to fail.
1530**
1531** The xInit method initializes the memory allocator.  For example,
1532** it might allocate any require mutexes or initialize internal data
1533** structures.  The xShutdown method is invoked (indirectly) by
1534** [sqlite3_shutdown()] and should deallocate any resources acquired
1535** by xInit.  The pAppData pointer is used as the only parameter to
1536** xInit and xShutdown.
1537**
1538** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1539** the xInit method, so the xInit method need not be threadsafe.  The
1540** xShutdown method is only called from [sqlite3_shutdown()] so it does
1541** not need to be threadsafe either.  For all other methods, SQLite
1542** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1543** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1544** it is by default) and so the methods are automatically serialized.
1545** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1546** methods must be threadsafe or else make their own arrangements for
1547** serialization.
1548**
1549** SQLite will never invoke xInit() more than once without an intervening
1550** call to xShutdown().
1551*/
1552typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1553struct sqlite3_mem_methods {
1554  void *(*xMalloc)(int);         /* Memory allocation function */
1555  void (*xFree)(void*);          /* Free a prior allocation */
1556  void *(*xRealloc)(void*,int);  /* Resize an allocation */
1557  int (*xSize)(void*);           /* Return the size of an allocation */
1558  int (*xRoundup)(int);          /* Round up request size to allocation size */
1559  int (*xInit)(void*);           /* Initialize the memory allocator */
1560  void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
1561  void *pAppData;                /* Argument to xInit() and xShutdown() */
1562};
1563
1564/*
1565** CAPI3REF: Configuration Options
1566** KEYWORDS: {configuration option}
1567**
1568** These constants are the available integer configuration options that
1569** can be passed as the first argument to the [sqlite3_config()] interface.
1570**
1571** New configuration options may be added in future releases of SQLite.
1572** Existing configuration options might be discontinued.  Applications
1573** should check the return code from [sqlite3_config()] to make sure that
1574** the call worked.  The [sqlite3_config()] interface will return a
1575** non-zero [error code] if a discontinued or unsupported configuration option
1576** is invoked.
1577**
1578** <dl>
1579** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1580** <dd>There are no arguments to this option.  ^This option sets the
1581** [threading mode] to Single-thread.  In other words, it disables
1582** all mutexing and puts SQLite into a mode where it can only be used
1583** by a single thread.   ^If SQLite is compiled with
1584** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1585** it is not possible to change the [threading mode] from its default
1586** value of Single-thread and so [sqlite3_config()] will return
1587** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1588** configuration option.</dd>
1589**
1590** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1591** <dd>There are no arguments to this option.  ^This option sets the
1592** [threading mode] to Multi-thread.  In other words, it disables
1593** mutexing on [database connection] and [prepared statement] objects.
1594** The application is responsible for serializing access to
1595** [database connections] and [prepared statements].  But other mutexes
1596** are enabled so that SQLite will be safe to use in a multi-threaded
1597** environment as long as no two threads attempt to use the same
1598** [database connection] at the same time.  ^If SQLite is compiled with
1599** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1600** it is not possible to set the Multi-thread [threading mode] and
1601** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1602** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1603**
1604** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1605** <dd>There are no arguments to this option.  ^This option sets the
1606** [threading mode] to Serialized. In other words, this option enables
1607** all mutexes including the recursive
1608** mutexes on [database connection] and [prepared statement] objects.
1609** In this mode (which is the default when SQLite is compiled with
1610** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1611** to [database connections] and [prepared statements] so that the
1612** application is free to use the same [database connection] or the
1613** same [prepared statement] in different threads at the same time.
1614** ^If SQLite is compiled with
1615** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1616** it is not possible to set the Serialized [threading mode] and
1617** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1618** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1619**
1620** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1621** <dd> ^(This option takes a single argument which is a pointer to an
1622** instance of the [sqlite3_mem_methods] structure.  The argument specifies
1623** alternative low-level memory allocation routines to be used in place of
1624** the memory allocation routines built into SQLite.)^ ^SQLite makes
1625** its own private copy of the content of the [sqlite3_mem_methods] structure
1626** before the [sqlite3_config()] call returns.</dd>
1627**
1628** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1629** <dd> ^(This option takes a single argument which is a pointer to an
1630** instance of the [sqlite3_mem_methods] structure.  The [sqlite3_mem_methods]
1631** structure is filled with the currently defined memory allocation routines.)^
1632** This option can be used to overload the default memory allocation
1633** routines with a wrapper that simulations memory allocation failure or
1634** tracks memory usage, for example. </dd>
1635**
1636** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1637** <dd> ^This option takes single argument of type int, interpreted as a
1638** boolean, which enables or disables the collection of memory allocation
1639** statistics. ^(When memory allocation statistics are disabled, the
1640** following SQLite interfaces become non-operational:
1641**   <ul>
1642**   <li> [sqlite3_memory_used()]
1643**   <li> [sqlite3_memory_highwater()]
1644**   <li> [sqlite3_soft_heap_limit64()]
1645**   <li> [sqlite3_status()]
1646**   </ul>)^
1647** ^Memory allocation statistics are enabled by default unless SQLite is
1648** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1649** allocation statistics are disabled by default.
1650** </dd>
1651**
1652** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1653** <dd> ^This option specifies a static memory buffer that SQLite can use for
1654** scratch memory.  There are three arguments:  A pointer an 8-byte
1655** aligned memory buffer from which the scratch allocations will be
1656** drawn, the size of each scratch allocation (sz),
1657** and the maximum number of scratch allocations (N).  The sz
1658** argument must be a multiple of 16.
1659** The first argument must be a pointer to an 8-byte aligned buffer
1660** of at least sz*N bytes of memory.
1661** ^SQLite will use no more than two scratch buffers per thread.  So
1662** N should be set to twice the expected maximum number of threads.
1663** ^SQLite will never require a scratch buffer that is more than 6
1664** times the database page size. ^If SQLite needs needs additional
1665** scratch memory beyond what is provided by this configuration option, then
1666** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
1667**
1668** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1669** <dd> ^This option specifies a static memory buffer that SQLite can use for
1670** the database page cache with the default page cache implementation.
1671** This configuration should not be used if an application-define page
1672** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option.
1673** There are three arguments to this option: A pointer to 8-byte aligned
1674** memory, the size of each page buffer (sz), and the number of pages (N).
1675** The sz argument should be the size of the largest database page
1676** (a power of two between 512 and 32768) plus a little extra for each
1677** page header.  ^The page header size is 20 to 40 bytes depending on
1678** the host architecture.  ^It is harmless, apart from the wasted memory,
1679** to make sz a little too large.  The first
1680** argument should point to an allocation of at least sz*N bytes of memory.
1681** ^SQLite will use the memory provided by the first argument to satisfy its
1682** memory needs for the first N pages that it adds to cache.  ^If additional
1683** page cache memory is needed beyond what is provided by this option, then
1684** SQLite goes to [sqlite3_malloc()] for the additional storage space.
1685** The pointer in the first argument must
1686** be aligned to an 8-byte boundary or subsequent behavior of SQLite
1687** will be undefined.</dd>
1688**
1689** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1690** <dd> ^This option specifies a static memory buffer that SQLite will use
1691** for all of its dynamic memory allocation needs beyond those provided
1692** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
1693** There are three arguments: An 8-byte aligned pointer to the memory,
1694** the number of bytes in the memory buffer, and the minimum allocation size.
1695** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1696** to using its default memory allocator (the system malloc() implementation),
1697** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
1698** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
1699** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
1700** allocator is engaged to handle all of SQLites memory allocation needs.
1701** The first pointer (the memory pointer) must be aligned to an 8-byte
1702** boundary or subsequent behavior of SQLite will be undefined.
1703** The minimum allocation size is capped at 2**12. Reasonable values
1704** for the minimum allocation size are 2**5 through 2**8.</dd>
1705**
1706** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1707** <dd> ^(This option takes a single argument which is a pointer to an
1708** instance of the [sqlite3_mutex_methods] structure.  The argument specifies
1709** alternative low-level mutex routines to be used in place
1710** the mutex routines built into SQLite.)^  ^SQLite makes a copy of the
1711** content of the [sqlite3_mutex_methods] structure before the call to
1712** [sqlite3_config()] returns. ^If SQLite is compiled with
1713** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1714** the entire mutexing subsystem is omitted from the build and hence calls to
1715** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1716** return [SQLITE_ERROR].</dd>
1717**
1718** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1719** <dd> ^(This option takes a single argument which is a pointer to an
1720** instance of the [sqlite3_mutex_methods] structure.  The
1721** [sqlite3_mutex_methods]
1722** structure is filled with the currently defined mutex routines.)^
1723** This option can be used to overload the default mutex allocation
1724** routines with a wrapper used to track mutex usage for performance
1725** profiling or testing, for example.   ^If SQLite is compiled with
1726** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1727** the entire mutexing subsystem is omitted from the build and hence calls to
1728** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1729** return [SQLITE_ERROR].</dd>
1730**
1731** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1732** <dd> ^(This option takes two arguments that determine the default
1733** memory allocation for the lookaside memory allocator on each
1734** [database connection].  The first argument is the
1735** size of each lookaside buffer slot and the second is the number of
1736** slots allocated to each database connection.)^  ^(This option sets the
1737** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1738** verb to [sqlite3_db_config()] can be used to change the lookaside
1739** configuration on individual connections.)^ </dd>
1740**
1741** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1742** <dd> ^(This option takes a single argument which is a pointer to
1743** an [sqlite3_pcache_methods2] object.  This object specifies the interface
1744** to a custom page cache implementation.)^  ^SQLite makes a copy of the
1745** object and uses it for page cache memory allocations.</dd>
1746**
1747** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1748** <dd> ^(This option takes a single argument which is a pointer to an
1749** [sqlite3_pcache_methods2] object.  SQLite copies of the current
1750** page cache implementation into that object.)^ </dd>
1751**
1752** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1753** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1754** global [error log].
1755** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1756** function with a call signature of void(*)(void*,int,const char*),
1757** and a pointer to void. ^If the function pointer is not NULL, it is
1758** invoked by [sqlite3_log()] to process each logging event.  ^If the
1759** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1760** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1761** passed through as the first parameter to the application-defined logger
1762** function whenever that function is invoked.  ^The second parameter to
1763** the logger function is a copy of the first parameter to the corresponding
1764** [sqlite3_log()] call and is intended to be a [result code] or an
1765** [extended result code].  ^The third parameter passed to the logger is
1766** log message after formatting via [sqlite3_snprintf()].
1767** The SQLite logging interface is not reentrant; the logger function
1768** supplied by the application must not invoke any SQLite interface.
1769** In a multi-threaded application, the application-defined logger
1770** function must be threadsafe. </dd>
1771**
1772** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1773** <dd>^(This option takes a single argument of type int. If non-zero, then
1774** URI handling is globally enabled. If the parameter is zero, then URI handling
1775** is globally disabled.)^ ^If URI handling is globally enabled, all filenames
1776** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or
1777** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1778** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1779** connection is opened. ^If it is globally disabled, filenames are
1780** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1781** database connection is opened. ^(By default, URI handling is globally
1782** disabled. The default value may be changed by compiling with the
1783** [SQLITE_USE_URI] symbol defined.)^
1784**
1785** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1786** <dd>^This option takes a single integer argument which is interpreted as
1787** a boolean in order to enable or disable the use of covering indices for
1788** full table scans in the query optimizer.  ^The default setting is determined
1789** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1790** if that compile-time option is omitted.
1791** The ability to disable the use of covering indices for full table scans
1792** is because some incorrectly coded legacy applications might malfunction
1793** when the optimization is enabled.  Providing the ability to
1794** disable the optimization allows the older, buggy application code to work
1795** without change even with newer versions of SQLite.
1796**
1797** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1798** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1799** <dd> These options are obsolete and should not be used by new code.
1800** They are retained for backwards compatibility but are now no-ops.
1801** </dd>
1802**
1803** [[SQLITE_CONFIG_SQLLOG]]
1804** <dt>SQLITE_CONFIG_SQLLOG
1805** <dd>This option is only available if sqlite is compiled with the
1806** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1807** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1808** The second should be of type (void*). The callback is invoked by the library
1809** in three separate circumstances, identified by the value passed as the
1810** fourth parameter. If the fourth parameter is 0, then the database connection
1811** passed as the second argument has just been opened. The third argument
1812** points to a buffer containing the name of the main database file. If the
1813** fourth parameter is 1, then the SQL statement that the third parameter
1814** points to has just been executed. Or, if the fourth parameter is 2, then
1815** the connection being passed as the second parameter is being closed. The
1816** third parameter is passed NULL In this case.  An example of using this
1817** configuration option can be seen in the "test_sqllog.c" source file in
1818** the canonical SQLite source tree.</dd>
1819**
1820** [[SQLITE_CONFIG_MMAP_SIZE]]
1821** <dt>SQLITE_CONFIG_MMAP_SIZE
1822** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1823** that are the default mmap size limit (the default setting for
1824** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1825** ^The default setting can be overridden by each database connection using
1826** either the [PRAGMA mmap_size] command, or by using the
1827** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
1828** cannot be changed at run-time.  Nor may the maximum allowed mmap size
1829** exceed the compile-time maximum mmap size set by the
1830** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1831** ^If either argument to this option is negative, then that argument is
1832** changed to its compile-time default.
1833**
1834** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
1835** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
1836** <dd>^This option is only available if SQLite is compiled for Windows
1837** with the [SQLITE_WIN32_MALLOC] pre-processor macro defined.
1838** SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1839** that specifies the maximum size of the created heap.
1840** </dl>
1841*/
1842#define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
1843#define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
1844#define SQLITE_CONFIG_SERIALIZED    3  /* nil */
1845#define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
1846#define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
1847#define SQLITE_CONFIG_SCRATCH       6  /* void*, int sz, int N */
1848#define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
1849#define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
1850#define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
1851#define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
1852#define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
1853/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1854#define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
1855#define SQLITE_CONFIG_PCACHE       14  /* no-op */
1856#define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
1857#define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
1858#define SQLITE_CONFIG_URI          17  /* int */
1859#define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
1860#define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
1861#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
1862#define SQLITE_CONFIG_SQLLOG       21  /* xSqllog, void* */
1863#define SQLITE_CONFIG_MMAP_SIZE    22  /* sqlite3_int64, sqlite3_int64 */
1864#define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
1865
1866/*
1867** CAPI3REF: Database Connection Configuration Options
1868**
1869** These constants are the available integer configuration options that
1870** can be passed as the second argument to the [sqlite3_db_config()] interface.
1871**
1872** New configuration options may be added in future releases of SQLite.
1873** Existing configuration options might be discontinued.  Applications
1874** should check the return code from [sqlite3_db_config()] to make sure that
1875** the call worked.  ^The [sqlite3_db_config()] interface will return a
1876** non-zero [error code] if a discontinued or unsupported configuration option
1877** is invoked.
1878**
1879** <dl>
1880** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1881** <dd> ^This option takes three additional arguments that determine the
1882** [lookaside memory allocator] configuration for the [database connection].
1883** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1884** pointer to a memory buffer to use for lookaside memory.
1885** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1886** may be NULL in which case SQLite will allocate the
1887** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1888** size of each lookaside buffer slot.  ^The third argument is the number of
1889** slots.  The size of the buffer in the first argument must be greater than
1890** or equal to the product of the second and third arguments.  The buffer
1891** must be aligned to an 8-byte boundary.  ^If the second argument to
1892** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1893** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
1894** configuration for a database connection can only be changed when that
1895** connection is not currently using lookaside memory, or in other words
1896** when the "current value" returned by
1897** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1898** Any attempt to change the lookaside memory configuration when lookaside
1899** memory is in use leaves the configuration unchanged and returns
1900** [SQLITE_BUSY].)^</dd>
1901**
1902** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1903** <dd> ^This option is used to enable or disable the enforcement of
1904** [foreign key constraints].  There should be two additional arguments.
1905** The first argument is an integer which is 0 to disable FK enforcement,
1906** positive to enable FK enforcement or negative to leave FK enforcement
1907** unchanged.  The second parameter is a pointer to an integer into which
1908** is written 0 or 1 to indicate whether FK enforcement is off or on
1909** following this call.  The second parameter may be a NULL pointer, in
1910** which case the FK enforcement setting is not reported back. </dd>
1911**
1912** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1913** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1914** There should be two additional arguments.
1915** The first argument is an integer which is 0 to disable triggers,
1916** positive to enable triggers or negative to leave the setting unchanged.
1917** The second parameter is a pointer to an integer into which
1918** is written 0 or 1 to indicate whether triggers are disabled or enabled
1919** following this call.  The second parameter may be a NULL pointer, in
1920** which case the trigger setting is not reported back. </dd>
1921**
1922** </dl>
1923*/
1924#define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */
1925#define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */
1926#define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */
1927
1928
1929/*
1930** CAPI3REF: Enable Or Disable Extended Result Codes
1931**
1932** ^The sqlite3_extended_result_codes() routine enables or disables the
1933** [extended result codes] feature of SQLite. ^The extended result
1934** codes are disabled by default for historical compatibility.
1935*/
1936SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
1937
1938/*
1939** CAPI3REF: Last Insert Rowid
1940**
1941** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
1942** has a unique 64-bit signed
1943** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1944** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1945** names are not also used by explicitly declared columns. ^If
1946** the table has a column of type [INTEGER PRIMARY KEY] then that column
1947** is another alias for the rowid.
1948**
1949** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the
1950** most recent successful [INSERT] into a rowid table or [virtual table]
1951** on database connection D.
1952** ^Inserts into [WITHOUT ROWID] tables are not recorded.
1953** ^If no successful [INSERT]s into rowid tables
1954** have ever occurred on the database connection D,
1955** then sqlite3_last_insert_rowid(D) returns zero.
1956**
1957** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
1958** method, then this routine will return the [rowid] of the inserted
1959** row as long as the trigger or virtual table method is running.
1960** But once the trigger or virtual table method ends, the value returned
1961** by this routine reverts to what it was before the trigger or virtual
1962** table method began.)^
1963**
1964** ^An [INSERT] that fails due to a constraint violation is not a
1965** successful [INSERT] and does not change the value returned by this
1966** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1967** and INSERT OR ABORT make no changes to the return value of this
1968** routine when their insertion fails.  ^(When INSERT OR REPLACE
1969** encounters a constraint violation, it does not fail.  The
1970** INSERT continues to completion after deleting rows that caused
1971** the constraint problem so INSERT OR REPLACE will always change
1972** the return value of this interface.)^
1973**
1974** ^For the purposes of this routine, an [INSERT] is considered to
1975** be successful even if it is subsequently rolled back.
1976**
1977** This function is accessible to SQL statements via the
1978** [last_insert_rowid() SQL function].
1979**
1980** If a separate thread performs a new [INSERT] on the same
1981** database connection while the [sqlite3_last_insert_rowid()]
1982** function is running and thus changes the last insert [rowid],
1983** then the value returned by [sqlite3_last_insert_rowid()] is
1984** unpredictable and might not equal either the old or the new
1985** last insert [rowid].
1986*/
1987SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
1988
1989/*
1990** CAPI3REF: Count The Number Of Rows Modified
1991**
1992** ^This function returns the number of database rows that were changed
1993** or inserted or deleted by the most recently completed SQL statement
1994** on the [database connection] specified by the first parameter.
1995** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
1996** or [DELETE] statement are counted.  Auxiliary changes caused by
1997** triggers or [foreign key actions] are not counted.)^ Use the
1998** [sqlite3_total_changes()] function to find the total number of changes
1999** including changes caused by triggers and foreign key actions.
2000**
2001** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
2002** are not counted.  Only real table changes are counted.
2003**
2004** ^(A "row change" is a change to a single row of a single table
2005** caused by an INSERT, DELETE, or UPDATE statement.  Rows that
2006** are changed as side effects of [REPLACE] constraint resolution,
2007** rollback, ABORT processing, [DROP TABLE], or by any other
2008** mechanisms do not count as direct row changes.)^
2009**
2010** A "trigger context" is a scope of execution that begins and
2011** ends with the script of a [CREATE TRIGGER | trigger].
2012** Most SQL statements are
2013** evaluated outside of any trigger.  This is the "top level"
2014** trigger context.  If a trigger fires from the top level, a
2015** new trigger context is entered for the duration of that one
2016** trigger.  Subtriggers create subcontexts for their duration.
2017**
2018** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
2019** not create a new trigger context.
2020**
2021** ^This function returns the number of direct row changes in the
2022** most recent INSERT, UPDATE, or DELETE statement within the same
2023** trigger context.
2024**
2025** ^Thus, when called from the top level, this function returns the
2026** number of changes in the most recent INSERT, UPDATE, or DELETE
2027** that also occurred at the top level.  ^(Within the body of a trigger,
2028** the sqlite3_changes() interface can be called to find the number of
2029** changes in the most recently completed INSERT, UPDATE, or DELETE
2030** statement within the body of the same trigger.
2031** However, the number returned does not include changes
2032** caused by subtriggers since those have their own context.)^
2033**
2034** See also the [sqlite3_total_changes()] interface, the
2035** [count_changes pragma], and the [changes() SQL function].
2036**
2037** If a separate thread makes changes on the same database connection
2038** while [sqlite3_changes()] is running then the value returned
2039** is unpredictable and not meaningful.
2040*/
2041SQLITE_API int sqlite3_changes(sqlite3*);
2042
2043/*
2044** CAPI3REF: Total Number Of Rows Modified
2045**
2046** ^This function returns the number of row changes caused by [INSERT],
2047** [UPDATE] or [DELETE] statements since the [database connection] was opened.
2048** ^(The count returned by sqlite3_total_changes() includes all changes
2049** from all [CREATE TRIGGER | trigger] contexts and changes made by
2050** [foreign key actions]. However,
2051** the count does not include changes used to implement [REPLACE] constraints,
2052** do rollbacks or ABORT processing, or [DROP TABLE] processing.  The
2053** count does not include rows of views that fire an [INSTEAD OF trigger],
2054** though if the INSTEAD OF trigger makes changes of its own, those changes
2055** are counted.)^
2056** ^The sqlite3_total_changes() function counts the changes as soon as
2057** the statement that makes them is completed (when the statement handle
2058** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
2059**
2060** See also the [sqlite3_changes()] interface, the
2061** [count_changes pragma], and the [total_changes() SQL function].
2062**
2063** If a separate thread makes changes on the same database connection
2064** while [sqlite3_total_changes()] is running then the value
2065** returned is unpredictable and not meaningful.
2066*/
2067SQLITE_API int sqlite3_total_changes(sqlite3*);
2068
2069/*
2070** CAPI3REF: Interrupt A Long-Running Query
2071**
2072** ^This function causes any pending database operation to abort and
2073** return at its earliest opportunity. This routine is typically
2074** called in response to a user action such as pressing "Cancel"
2075** or Ctrl-C where the user wants a long query operation to halt
2076** immediately.
2077**
2078** ^It is safe to call this routine from a thread different from the
2079** thread that is currently running the database operation.  But it
2080** is not safe to call this routine with a [database connection] that
2081** is closed or might close before sqlite3_interrupt() returns.
2082**
2083** ^If an SQL operation is very nearly finished at the time when
2084** sqlite3_interrupt() is called, then it might not have an opportunity
2085** to be interrupted and might continue to completion.
2086**
2087** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2088** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2089** that is inside an explicit transaction, then the entire transaction
2090** will be rolled back automatically.
2091**
2092** ^The sqlite3_interrupt(D) call is in effect until all currently running
2093** SQL statements on [database connection] D complete.  ^Any new SQL statements
2094** that are started after the sqlite3_interrupt() call and before the
2095** running statements reaches zero are interrupted as if they had been
2096** running prior to the sqlite3_interrupt() call.  ^New SQL statements
2097** that are started after the running statement count reaches zero are
2098** not effected by the sqlite3_interrupt().
2099** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2100** SQL statements is a no-op and has no effect on SQL statements
2101** that are started after the sqlite3_interrupt() call returns.
2102**
2103** If the database connection closes while [sqlite3_interrupt()]
2104** is running then bad things will likely happen.
2105*/
2106SQLITE_API void sqlite3_interrupt(sqlite3*);
2107
2108/*
2109** CAPI3REF: Determine If An SQL Statement Is Complete
2110**
2111** These routines are useful during command-line input to determine if the
2112** currently entered text seems to form a complete SQL statement or
2113** if additional input is needed before sending the text into
2114** SQLite for parsing.  ^These routines return 1 if the input string
2115** appears to be a complete SQL statement.  ^A statement is judged to be
2116** complete if it ends with a semicolon token and is not a prefix of a
2117** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
2118** string literals or quoted identifier names or comments are not
2119** independent tokens (they are part of the token in which they are
2120** embedded) and thus do not count as a statement terminator.  ^Whitespace
2121** and comments that follow the final semicolon are ignored.
2122**
2123** ^These routines return 0 if the statement is incomplete.  ^If a
2124** memory allocation fails, then SQLITE_NOMEM is returned.
2125**
2126** ^These routines do not parse the SQL statements thus
2127** will not detect syntactically incorrect SQL.
2128**
2129** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2130** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2131** automatically by sqlite3_complete16().  If that initialization fails,
2132** then the return value from sqlite3_complete16() will be non-zero
2133** regardless of whether or not the input SQL is complete.)^
2134**
2135** The input to [sqlite3_complete()] must be a zero-terminated
2136** UTF-8 string.
2137**
2138** The input to [sqlite3_complete16()] must be a zero-terminated
2139** UTF-16 string in native byte order.
2140*/
2141SQLITE_API int sqlite3_complete(const char *sql);
2142SQLITE_API int sqlite3_complete16(const void *sql);
2143
2144/*
2145** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2146**
2147** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2148** that might be invoked with argument P whenever
2149** an attempt is made to access a database table associated with
2150** [database connection] D when another thread
2151** or process has the table locked.
2152** The sqlite3_busy_handler() interface is used to implement
2153** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2154**
2155** ^If the busy callback is NULL, then [SQLITE_BUSY]
2156** is returned immediately upon encountering the lock.  ^If the busy callback
2157** is not NULL, then the callback might be invoked with two arguments.
2158**
2159** ^The first argument to the busy handler is a copy of the void* pointer which
2160** is the third argument to sqlite3_busy_handler().  ^The second argument to
2161** the busy handler callback is the number of times that the busy handler has
2162** been invoked for the same locking event.  ^If the
2163** busy callback returns 0, then no additional attempts are made to
2164** access the database and [SQLITE_BUSY] is returned
2165** to the application.
2166** ^If the callback returns non-zero, then another attempt
2167** is made to access the database and the cycle repeats.
2168**
2169** The presence of a busy handler does not guarantee that it will be invoked
2170** when there is lock contention. ^If SQLite determines that invoking the busy
2171** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2172** to the application instead of invoking the
2173** busy handler.
2174** Consider a scenario where one process is holding a read lock that
2175** it is trying to promote to a reserved lock and
2176** a second process is holding a reserved lock that it is trying
2177** to promote to an exclusive lock.  The first process cannot proceed
2178** because it is blocked by the second and the second process cannot
2179** proceed because it is blocked by the first.  If both processes
2180** invoke the busy handlers, neither will make any progress.  Therefore,
2181** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2182** will induce the first process to release its read lock and allow
2183** the second process to proceed.
2184**
2185** ^The default busy callback is NULL.
2186**
2187** ^(There can only be a single busy handler defined for each
2188** [database connection].  Setting a new busy handler clears any
2189** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
2190** or evaluating [PRAGMA busy_timeout=N] will change the
2191** busy handler and thus clear any previously set busy handler.
2192**
2193** The busy callback should not take any actions which modify the
2194** database connection that invoked the busy handler.  In other words,
2195** the busy handler is not reentrant.  Any such actions
2196** result in undefined behavior.
2197**
2198** A busy handler must not close the database connection
2199** or [prepared statement] that invoked the busy handler.
2200*/
2201SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
2202
2203/*
2204** CAPI3REF: Set A Busy Timeout
2205**
2206** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2207** for a specified amount of time when a table is locked.  ^The handler
2208** will sleep multiple times until at least "ms" milliseconds of sleeping
2209** have accumulated.  ^After at least "ms" milliseconds of sleeping,
2210** the handler returns 0 which causes [sqlite3_step()] to return
2211** [SQLITE_BUSY].
2212**
2213** ^Calling this routine with an argument less than or equal to zero
2214** turns off all busy handlers.
2215**
2216** ^(There can only be a single busy handler for a particular
2217** [database connection] any any given moment.  If another busy handler
2218** was defined  (using [sqlite3_busy_handler()]) prior to calling
2219** this routine, that other busy handler is cleared.)^
2220**
2221** See also:  [PRAGMA busy_timeout]
2222*/
2223SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2224
2225/*
2226** CAPI3REF: Convenience Routines For Running Queries
2227**
2228** This is a legacy interface that is preserved for backwards compatibility.
2229** Use of this interface is not recommended.
2230**
2231** Definition: A <b>result table</b> is memory data structure created by the
2232** [sqlite3_get_table()] interface.  A result table records the
2233** complete query results from one or more queries.
2234**
2235** The table conceptually has a number of rows and columns.  But
2236** these numbers are not part of the result table itself.  These
2237** numbers are obtained separately.  Let N be the number of rows
2238** and M be the number of columns.
2239**
2240** A result table is an array of pointers to zero-terminated UTF-8 strings.
2241** There are (N+1)*M elements in the array.  The first M pointers point
2242** to zero-terminated strings that  contain the names of the columns.
2243** The remaining entries all point to query results.  NULL values result
2244** in NULL pointers.  All other values are in their UTF-8 zero-terminated
2245** string representation as returned by [sqlite3_column_text()].
2246**
2247** A result table might consist of one or more memory allocations.
2248** It is not safe to pass a result table directly to [sqlite3_free()].
2249** A result table should be deallocated using [sqlite3_free_table()].
2250**
2251** ^(As an example of the result table format, suppose a query result
2252** is as follows:
2253**
2254** <blockquote><pre>
2255**        Name        | Age
2256**        -----------------------
2257**        Alice       | 43
2258**        Bob         | 28
2259**        Cindy       | 21
2260** </pre></blockquote>
2261**
2262** There are two column (M==2) and three rows (N==3).  Thus the
2263** result table has 8 entries.  Suppose the result table is stored
2264** in an array names azResult.  Then azResult holds this content:
2265**
2266** <blockquote><pre>
2267**        azResult&#91;0] = "Name";
2268**        azResult&#91;1] = "Age";
2269**        azResult&#91;2] = "Alice";
2270**        azResult&#91;3] = "43";
2271**        azResult&#91;4] = "Bob";
2272**        azResult&#91;5] = "28";
2273**        azResult&#91;6] = "Cindy";
2274**        azResult&#91;7] = "21";
2275** </pre></blockquote>)^
2276**
2277** ^The sqlite3_get_table() function evaluates one or more
2278** semicolon-separated SQL statements in the zero-terminated UTF-8
2279** string of its 2nd parameter and returns a result table to the
2280** pointer given in its 3rd parameter.
2281**
2282** After the application has finished with the result from sqlite3_get_table(),
2283** it must pass the result table pointer to sqlite3_free_table() in order to
2284** release the memory that was malloced.  Because of the way the
2285** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2286** function must not try to call [sqlite3_free()] directly.  Only
2287** [sqlite3_free_table()] is able to release the memory properly and safely.
2288**
2289** The sqlite3_get_table() interface is implemented as a wrapper around
2290** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
2291** to any internal data structures of SQLite.  It uses only the public
2292** interface defined here.  As a consequence, errors that occur in the
2293** wrapper layer outside of the internal [sqlite3_exec()] call are not
2294** reflected in subsequent calls to [sqlite3_errcode()] or
2295** [sqlite3_errmsg()].
2296*/
2297SQLITE_API int sqlite3_get_table(
2298  sqlite3 *db,          /* An open database */
2299  const char *zSql,     /* SQL to be evaluated */
2300  char ***pazResult,    /* Results of the query */
2301  int *pnRow,           /* Number of result rows written here */
2302  int *pnColumn,        /* Number of result columns written here */
2303  char **pzErrmsg       /* Error msg written here */
2304);
2305SQLITE_API void sqlite3_free_table(char **result);
2306
2307/*
2308** CAPI3REF: Formatted String Printing Functions
2309**
2310** These routines are work-alikes of the "printf()" family of functions
2311** from the standard C library.
2312**
2313** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2314** results into memory obtained from [sqlite3_malloc()].
2315** The strings returned by these two routines should be
2316** released by [sqlite3_free()].  ^Both routines return a
2317** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2318** memory to hold the resulting string.
2319**
2320** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2321** the standard C library.  The result is written into the
2322** buffer supplied as the second parameter whose size is given by
2323** the first parameter. Note that the order of the
2324** first two parameters is reversed from snprintf().)^  This is an
2325** historical accident that cannot be fixed without breaking
2326** backwards compatibility.  ^(Note also that sqlite3_snprintf()
2327** returns a pointer to its buffer instead of the number of
2328** characters actually written into the buffer.)^  We admit that
2329** the number of characters written would be a more useful return
2330** value but we cannot change the implementation of sqlite3_snprintf()
2331** now without breaking compatibility.
2332**
2333** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2334** guarantees that the buffer is always zero-terminated.  ^The first
2335** parameter "n" is the total size of the buffer, including space for
2336** the zero terminator.  So the longest string that can be completely
2337** written will be n-1 characters.
2338**
2339** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2340**
2341** These routines all implement some additional formatting
2342** options that are useful for constructing SQL statements.
2343** All of the usual printf() formatting options apply.  In addition, there
2344** is are "%q", "%Q", and "%z" options.
2345**
2346** ^(The %q option works like %s in that it substitutes a nul-terminated
2347** string from the argument list.  But %q also doubles every '\'' character.
2348** %q is designed for use inside a string literal.)^  By doubling each '\''
2349** character it escapes that character and allows it to be inserted into
2350** the string.
2351**
2352** For example, assume the string variable zText contains text as follows:
2353**
2354** <blockquote><pre>
2355**  char *zText = "It's a happy day!";
2356** </pre></blockquote>
2357**
2358** One can use this text in an SQL statement as follows:
2359**
2360** <blockquote><pre>
2361**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2362**  sqlite3_exec(db, zSQL, 0, 0, 0);
2363**  sqlite3_free(zSQL);
2364** </pre></blockquote>
2365**
2366** Because the %q format string is used, the '\'' character in zText
2367** is escaped and the SQL generated is as follows:
2368**
2369** <blockquote><pre>
2370**  INSERT INTO table1 VALUES('It''s a happy day!')
2371** </pre></blockquote>
2372**
2373** This is correct.  Had we used %s instead of %q, the generated SQL
2374** would have looked like this:
2375**
2376** <blockquote><pre>
2377**  INSERT INTO table1 VALUES('It's a happy day!');
2378** </pre></blockquote>
2379**
2380** This second example is an SQL syntax error.  As a general rule you should
2381** always use %q instead of %s when inserting text into a string literal.
2382**
2383** ^(The %Q option works like %q except it also adds single quotes around
2384** the outside of the total string.  Additionally, if the parameter in the
2385** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2386** single quotes).)^  So, for example, one could say:
2387**
2388** <blockquote><pre>
2389**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2390**  sqlite3_exec(db, zSQL, 0, 0, 0);
2391**  sqlite3_free(zSQL);
2392** </pre></blockquote>
2393**
2394** The code above will render a correct SQL statement in the zSQL
2395** variable even if the zText variable is a NULL pointer.
2396**
2397** ^(The "%z" formatting option works like "%s" but with the
2398** addition that after the string has been read and copied into
2399** the result, [sqlite3_free()] is called on the input string.)^
2400*/
2401SQLITE_API char *sqlite3_mprintf(const char*,...);
2402SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2403SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2404SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2405
2406/*
2407** CAPI3REF: Memory Allocation Subsystem
2408**
2409** The SQLite core uses these three routines for all of its own
2410** internal memory allocation needs. "Core" in the previous sentence
2411** does not include operating-system specific VFS implementation.  The
2412** Windows VFS uses native malloc() and free() for some operations.
2413**
2414** ^The sqlite3_malloc() routine returns a pointer to a block
2415** of memory at least N bytes in length, where N is the parameter.
2416** ^If sqlite3_malloc() is unable to obtain sufficient free
2417** memory, it returns a NULL pointer.  ^If the parameter N to
2418** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2419** a NULL pointer.
2420**
2421** ^Calling sqlite3_free() with a pointer previously returned
2422** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2423** that it might be reused.  ^The sqlite3_free() routine is
2424** a no-op if is called with a NULL pointer.  Passing a NULL pointer
2425** to sqlite3_free() is harmless.  After being freed, memory
2426** should neither be read nor written.  Even reading previously freed
2427** memory might result in a segmentation fault or other severe error.
2428** Memory corruption, a segmentation fault, or other severe error
2429** might result if sqlite3_free() is called with a non-NULL pointer that
2430** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2431**
2432** ^(The sqlite3_realloc() interface attempts to resize a
2433** prior memory allocation to be at least N bytes, where N is the
2434** second parameter.  The memory allocation to be resized is the first
2435** parameter.)^ ^ If the first parameter to sqlite3_realloc()
2436** is a NULL pointer then its behavior is identical to calling
2437** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
2438** ^If the second parameter to sqlite3_realloc() is zero or
2439** negative then the behavior is exactly the same as calling
2440** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
2441** ^sqlite3_realloc() returns a pointer to a memory allocation
2442** of at least N bytes in size or NULL if sufficient memory is unavailable.
2443** ^If M is the size of the prior allocation, then min(N,M) bytes
2444** of the prior allocation are copied into the beginning of buffer returned
2445** by sqlite3_realloc() and the prior allocation is freed.
2446** ^If sqlite3_realloc() returns NULL, then the prior allocation
2447** is not freed.
2448**
2449** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
2450** is always aligned to at least an 8 byte boundary, or to a
2451** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2452** option is used.
2453**
2454** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2455** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2456** implementation of these routines to be omitted.  That capability
2457** is no longer provided.  Only built-in memory allocators can be used.
2458**
2459** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2460** the system malloc() and free() directly when converting
2461** filenames between the UTF-8 encoding used by SQLite
2462** and whatever filename encoding is used by the particular Windows
2463** installation.  Memory allocation errors were detected, but
2464** they were reported back as [SQLITE_CANTOPEN] or
2465** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2466**
2467** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2468** must be either NULL or else pointers obtained from a prior
2469** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2470** not yet been released.
2471**
2472** The application must not read or write any part of
2473** a block of memory after it has been released using
2474** [sqlite3_free()] or [sqlite3_realloc()].
2475*/
2476SQLITE_API void *sqlite3_malloc(int);
2477SQLITE_API void *sqlite3_realloc(void*, int);
2478SQLITE_API void sqlite3_free(void*);
2479
2480/*
2481** CAPI3REF: Memory Allocator Statistics
2482**
2483** SQLite provides these two interfaces for reporting on the status
2484** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2485** routines, which form the built-in memory allocation subsystem.
2486**
2487** ^The [sqlite3_memory_used()] routine returns the number of bytes
2488** of memory currently outstanding (malloced but not freed).
2489** ^The [sqlite3_memory_highwater()] routine returns the maximum
2490** value of [sqlite3_memory_used()] since the high-water mark
2491** was last reset.  ^The values returned by [sqlite3_memory_used()] and
2492** [sqlite3_memory_highwater()] include any overhead
2493** added by SQLite in its implementation of [sqlite3_malloc()],
2494** but not overhead added by the any underlying system library
2495** routines that [sqlite3_malloc()] may call.
2496**
2497** ^The memory high-water mark is reset to the current value of
2498** [sqlite3_memory_used()] if and only if the parameter to
2499** [sqlite3_memory_highwater()] is true.  ^The value returned
2500** by [sqlite3_memory_highwater(1)] is the high-water mark
2501** prior to the reset.
2502*/
2503SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2504SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2505
2506/*
2507** CAPI3REF: Pseudo-Random Number Generator
2508**
2509** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2510** select random [ROWID | ROWIDs] when inserting new records into a table that
2511** already uses the largest possible [ROWID].  The PRNG is also used for
2512** the build-in random() and randomblob() SQL functions.  This interface allows
2513** applications to access the same PRNG for other purposes.
2514**
2515** ^A call to this routine stores N bytes of randomness into buffer P.
2516** ^If N is less than one, then P can be a NULL pointer.
2517**
2518** ^If this routine has not been previously called or if the previous
2519** call had N less than one, then the PRNG is seeded using randomness
2520** obtained from the xRandomness method of the default [sqlite3_vfs] object.
2521** ^If the previous call to this routine had an N of 1 or more then
2522** the pseudo-randomness is generated
2523** internally and without recourse to the [sqlite3_vfs] xRandomness
2524** method.
2525*/
2526SQLITE_API void sqlite3_randomness(int N, void *P);
2527
2528/*
2529** CAPI3REF: Compile-Time Authorization Callbacks
2530**
2531** ^This routine registers an authorizer callback with a particular
2532** [database connection], supplied in the first argument.
2533** ^The authorizer callback is invoked as SQL statements are being compiled
2534** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2535** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  ^At various
2536** points during the compilation process, as logic is being created
2537** to perform various actions, the authorizer callback is invoked to
2538** see if those actions are allowed.  ^The authorizer callback should
2539** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2540** specific action but allow the SQL statement to continue to be
2541** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2542** rejected with an error.  ^If the authorizer callback returns
2543** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2544** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2545** the authorizer will fail with an error message.
2546**
2547** When the callback returns [SQLITE_OK], that means the operation
2548** requested is ok.  ^When the callback returns [SQLITE_DENY], the
2549** [sqlite3_prepare_v2()] or equivalent call that triggered the
2550** authorizer will fail with an error message explaining that
2551** access is denied.
2552**
2553** ^The first parameter to the authorizer callback is a copy of the third
2554** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2555** to the callback is an integer [SQLITE_COPY | action code] that specifies
2556** the particular action to be authorized. ^The third through sixth parameters
2557** to the callback are zero-terminated strings that contain additional
2558** details about the action to be authorized.
2559**
2560** ^If the action code is [SQLITE_READ]
2561** and the callback returns [SQLITE_IGNORE] then the
2562** [prepared statement] statement is constructed to substitute
2563** a NULL value in place of the table column that would have
2564** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
2565** return can be used to deny an untrusted user access to individual
2566** columns of a table.
2567** ^If the action code is [SQLITE_DELETE] and the callback returns
2568** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2569** [truncate optimization] is disabled and all rows are deleted individually.
2570**
2571** An authorizer is used when [sqlite3_prepare | preparing]
2572** SQL statements from an untrusted source, to ensure that the SQL statements
2573** do not try to access data they are not allowed to see, or that they do not
2574** try to execute malicious statements that damage the database.  For
2575** example, an application may allow a user to enter arbitrary
2576** SQL queries for evaluation by a database.  But the application does
2577** not want the user to be able to make arbitrary changes to the
2578** database.  An authorizer could then be put in place while the
2579** user-entered SQL is being [sqlite3_prepare | prepared] that
2580** disallows everything except [SELECT] statements.
2581**
2582** Applications that need to process SQL from untrusted sources
2583** might also consider lowering resource limits using [sqlite3_limit()]
2584** and limiting database size using the [max_page_count] [PRAGMA]
2585** in addition to using an authorizer.
2586**
2587** ^(Only a single authorizer can be in place on a database connection
2588** at a time.  Each call to sqlite3_set_authorizer overrides the
2589** previous call.)^  ^Disable the authorizer by installing a NULL callback.
2590** The authorizer is disabled by default.
2591**
2592** The authorizer callback must not do anything that will modify
2593** the database connection that invoked the authorizer callback.
2594** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2595** database connections for the meaning of "modify" in this paragraph.
2596**
2597** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2598** statement might be re-prepared during [sqlite3_step()] due to a
2599** schema change.  Hence, the application should ensure that the
2600** correct authorizer callback remains in place during the [sqlite3_step()].
2601**
2602** ^Note that the authorizer callback is invoked only during
2603** [sqlite3_prepare()] or its variants.  Authorization is not
2604** performed during statement evaluation in [sqlite3_step()], unless
2605** as stated in the previous paragraph, sqlite3_step() invokes
2606** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2607*/
2608SQLITE_API int sqlite3_set_authorizer(
2609  sqlite3*,
2610  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2611  void *pUserData
2612);
2613
2614/*
2615** CAPI3REF: Authorizer Return Codes
2616**
2617** The [sqlite3_set_authorizer | authorizer callback function] must
2618** return either [SQLITE_OK] or one of these two constants in order
2619** to signal SQLite whether or not the action is permitted.  See the
2620** [sqlite3_set_authorizer | authorizer documentation] for additional
2621** information.
2622**
2623** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2624** returned from the [sqlite3_vtab_on_conflict()] interface.
2625*/
2626#define SQLITE_DENY   1   /* Abort the SQL statement with an error */
2627#define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
2628
2629/*
2630** CAPI3REF: Authorizer Action Codes
2631**
2632** The [sqlite3_set_authorizer()] interface registers a callback function
2633** that is invoked to authorize certain SQL statement actions.  The
2634** second parameter to the callback is an integer code that specifies
2635** what action is being authorized.  These are the integer action codes that
2636** the authorizer callback may be passed.
2637**
2638** These action code values signify what kind of operation is to be
2639** authorized.  The 3rd and 4th parameters to the authorization
2640** callback function will be parameters or NULL depending on which of these
2641** codes is used as the second parameter.  ^(The 5th parameter to the
2642** authorizer callback is the name of the database ("main", "temp",
2643** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
2644** is the name of the inner-most trigger or view that is responsible for
2645** the access attempt or NULL if this access attempt is directly from
2646** top-level SQL code.
2647*/
2648/******************************************* 3rd ************ 4th ***********/
2649#define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
2650#define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
2651#define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
2652#define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
2653#define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
2654#define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
2655#define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
2656#define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
2657#define SQLITE_DELETE                9   /* Table Name      NULL            */
2658#define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
2659#define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
2660#define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
2661#define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
2662#define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
2663#define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
2664#define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
2665#define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
2666#define SQLITE_INSERT               18   /* Table Name      NULL            */
2667#define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
2668#define SQLITE_READ                 20   /* Table Name      Column Name     */
2669#define SQLITE_SELECT               21   /* NULL            NULL            */
2670#define SQLITE_TRANSACTION          22   /* Operation       NULL            */
2671#define SQLITE_UPDATE               23   /* Table Name      Column Name     */
2672#define SQLITE_ATTACH               24   /* Filename        NULL            */
2673#define SQLITE_DETACH               25   /* Database Name   NULL            */
2674#define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
2675#define SQLITE_REINDEX              27   /* Index Name      NULL            */
2676#define SQLITE_ANALYZE              28   /* Table Name      NULL            */
2677#define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
2678#define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
2679#define SQLITE_FUNCTION             31   /* NULL            Function Name   */
2680#define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
2681#define SQLITE_COPY                  0   /* No longer used */
2682#define SQLITE_RECURSIVE            33   /* NULL            NULL            */
2683
2684/*
2685** CAPI3REF: Tracing And Profiling Functions
2686**
2687** These routines register callback functions that can be used for
2688** tracing and profiling the execution of SQL statements.
2689**
2690** ^The callback function registered by sqlite3_trace() is invoked at
2691** various times when an SQL statement is being run by [sqlite3_step()].
2692** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2693** SQL statement text as the statement first begins executing.
2694** ^(Additional sqlite3_trace() callbacks might occur
2695** as each triggered subprogram is entered.  The callbacks for triggers
2696** contain a UTF-8 SQL comment that identifies the trigger.)^
2697**
2698** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2699** the length of [bound parameter] expansion in the output of sqlite3_trace().
2700**
2701** ^The callback function registered by sqlite3_profile() is invoked
2702** as each SQL statement finishes.  ^The profile callback contains
2703** the original statement text and an estimate of wall-clock time
2704** of how long that statement took to run.  ^The profile callback
2705** time is in units of nanoseconds, however the current implementation
2706** is only capable of millisecond resolution so the six least significant
2707** digits in the time are meaningless.  Future versions of SQLite
2708** might provide greater resolution on the profiler callback.  The
2709** sqlite3_profile() function is considered experimental and is
2710** subject to change in future versions of SQLite.
2711*/
2712SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2713SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
2714   void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2715
2716/*
2717** CAPI3REF: Query Progress Callbacks
2718**
2719** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2720** function X to be invoked periodically during long running calls to
2721** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2722** database connection D.  An example use for this
2723** interface is to keep a GUI updated during a large query.
2724**
2725** ^The parameter P is passed through as the only parameter to the
2726** callback function X.  ^The parameter N is the approximate number of
2727** [virtual machine instructions] that are evaluated between successive
2728** invocations of the callback X.  ^If N is less than one then the progress
2729** handler is disabled.
2730**
2731** ^Only a single progress handler may be defined at one time per
2732** [database connection]; setting a new progress handler cancels the
2733** old one.  ^Setting parameter X to NULL disables the progress handler.
2734** ^The progress handler is also disabled by setting N to a value less
2735** than 1.
2736**
2737** ^If the progress callback returns non-zero, the operation is
2738** interrupted.  This feature can be used to implement a
2739** "Cancel" button on a GUI progress dialog box.
2740**
2741** The progress handler callback must not do anything that will modify
2742** the database connection that invoked the progress handler.
2743** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2744** database connections for the meaning of "modify" in this paragraph.
2745**
2746*/
2747SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2748
2749/*
2750** CAPI3REF: Opening A New Database Connection
2751**
2752** ^These routines open an SQLite database file as specified by the
2753** filename argument. ^The filename argument is interpreted as UTF-8 for
2754** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2755** order for sqlite3_open16(). ^(A [database connection] handle is usually
2756** returned in *ppDb, even if an error occurs.  The only exception is that
2757** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2758** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2759** object.)^ ^(If the database is opened (and/or created) successfully, then
2760** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
2761** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2762** an English language description of the error following a failure of any
2763** of the sqlite3_open() routines.
2764**
2765** ^The default encoding for the database will be UTF-8 if
2766** sqlite3_open() or sqlite3_open_v2() is called and
2767** UTF-16 in the native byte order if sqlite3_open16() is used.
2768**
2769** Whether or not an error occurs when it is opened, resources
2770** associated with the [database connection] handle should be released by
2771** passing it to [sqlite3_close()] when it is no longer required.
2772**
2773** The sqlite3_open_v2() interface works like sqlite3_open()
2774** except that it accepts two additional parameters for additional control
2775** over the new database connection.  ^(The flags parameter to
2776** sqlite3_open_v2() can take one of
2777** the following three values, optionally combined with the
2778** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2779** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
2780**
2781** <dl>
2782** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2783** <dd>The database is opened in read-only mode.  If the database does not
2784** already exist, an error is returned.</dd>)^
2785**
2786** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2787** <dd>The database is opened for reading and writing if possible, or reading
2788** only if the file is write protected by the operating system.  In either
2789** case the database must already exist, otherwise an error is returned.</dd>)^
2790**
2791** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2792** <dd>The database is opened for reading and writing, and is created if
2793** it does not already exist. This is the behavior that is always used for
2794** sqlite3_open() and sqlite3_open16().</dd>)^
2795** </dl>
2796**
2797** If the 3rd parameter to sqlite3_open_v2() is not one of the
2798** combinations shown above optionally combined with other
2799** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
2800** then the behavior is undefined.
2801**
2802** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2803** opens in the multi-thread [threading mode] as long as the single-thread
2804** mode has not been set at compile-time or start-time.  ^If the
2805** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2806** in the serialized [threading mode] unless single-thread was
2807** previously selected at compile-time or start-time.
2808** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2809** eligible to use [shared cache mode], regardless of whether or not shared
2810** cache is enabled using [sqlite3_enable_shared_cache()].  ^The
2811** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2812** participate in [shared cache mode] even if it is enabled.
2813**
2814** ^The fourth parameter to sqlite3_open_v2() is the name of the
2815** [sqlite3_vfs] object that defines the operating system interface that
2816** the new database connection should use.  ^If the fourth parameter is
2817** a NULL pointer then the default [sqlite3_vfs] object is used.
2818**
2819** ^If the filename is ":memory:", then a private, temporary in-memory database
2820** is created for the connection.  ^This in-memory database will vanish when
2821** the database connection is closed.  Future versions of SQLite might
2822** make use of additional special filenames that begin with the ":" character.
2823** It is recommended that when a database filename actually does begin with
2824** a ":" character you should prefix the filename with a pathname such as
2825** "./" to avoid ambiguity.
2826**
2827** ^If the filename is an empty string, then a private, temporary
2828** on-disk database will be created.  ^This private database will be
2829** automatically deleted as soon as the database connection is closed.
2830**
2831** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
2832**
2833** ^If [URI filename] interpretation is enabled, and the filename argument
2834** begins with "file:", then the filename is interpreted as a URI. ^URI
2835** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
2836** set in the fourth argument to sqlite3_open_v2(), or if it has
2837** been enabled globally using the [SQLITE_CONFIG_URI] option with the
2838** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
2839** As of SQLite version 3.7.7, URI filename interpretation is turned off
2840** by default, but future releases of SQLite might enable URI filename
2841** interpretation by default.  See "[URI filenames]" for additional
2842** information.
2843**
2844** URI filenames are parsed according to RFC 3986. ^If the URI contains an
2845** authority, then it must be either an empty string or the string
2846** "localhost". ^If the authority is not an empty string or "localhost", an
2847** error is returned to the caller. ^The fragment component of a URI, if
2848** present, is ignored.
2849**
2850** ^SQLite uses the path component of the URI as the name of the disk file
2851** which contains the database. ^If the path begins with a '/' character,
2852** then it is interpreted as an absolute path. ^If the path does not begin
2853** with a '/' (meaning that the authority section is omitted from the URI)
2854** then the path is interpreted as a relative path.
2855** ^On windows, the first component of an absolute path
2856** is a drive specification (e.g. "C:").
2857**
2858** [[core URI query parameters]]
2859** The query component of a URI may contain parameters that are interpreted
2860** either by SQLite itself, or by a [VFS | custom VFS implementation].
2861** SQLite interprets the following three query parameters:
2862**
2863** <ul>
2864**   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
2865**     a VFS object that provides the operating system interface that should
2866**     be used to access the database file on disk. ^If this option is set to
2867**     an empty string the default VFS object is used. ^Specifying an unknown
2868**     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
2869**     present, then the VFS specified by the option takes precedence over
2870**     the value passed as the fourth parameter to sqlite3_open_v2().
2871**
2872**   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
2873**     "rwc", or "memory". Attempting to set it to any other value is
2874**     an error)^.
2875**     ^If "ro" is specified, then the database is opened for read-only
2876**     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
2877**     third argument to sqlite3_open_v2(). ^If the mode option is set to
2878**     "rw", then the database is opened for read-write (but not create)
2879**     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
2880**     been set. ^Value "rwc" is equivalent to setting both
2881**     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
2882**     set to "memory" then a pure [in-memory database] that never reads
2883**     or writes from disk is used. ^It is an error to specify a value for
2884**     the mode parameter that is less restrictive than that specified by
2885**     the flags passed in the third parameter to sqlite3_open_v2().
2886**
2887**   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
2888**     "private". ^Setting it to "shared" is equivalent to setting the
2889**     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
2890**     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
2891**     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
2892**     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
2893**     a URI filename, its value overrides any behavior requested by setting
2894**     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
2895**
2896**  <li> <b>psow</b>: ^The psow parameter may be "true" (or "on" or "yes" or
2897**     "1") or "false" (or "off" or "no" or "0") to indicate that the
2898**     [powersafe overwrite] property does or does not apply to the
2899**     storage media on which the database file resides.  ^The psow query
2900**     parameter only works for the built-in unix and Windows VFSes.
2901**
2902**  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
2903**     which if set disables file locking in rollback journal modes.  This
2904**     is useful for accessing a database on a filesystem that does not
2905**     support locking.  Caution:  Database corruption might result if two
2906**     or more processes write to the same database and any one of those
2907**     processes uses nolock=1.
2908**
2909**  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
2910**     parameter that indicates that the database file is stored on
2911**     read-only media.  ^When immutable is set, SQLite assumes that the
2912**     database file cannot be changed, even by a process with higher
2913**     privilege, and so the database is opened read-only and all locking
2914**     and change detection is disabled.  Caution: Setting the immutable
2915**     property on a database file that does in fact change can result
2916**     in incorrect query results and/or [SQLITE_CORRUPT] errors.
2917**     See also: [SQLITE_IOCAP_IMMUTABLE].
2918**
2919** </ul>
2920**
2921** ^Specifying an unknown parameter in the query component of a URI is not an
2922** error.  Future versions of SQLite might understand additional query
2923** parameters.  See "[query parameters with special meaning to SQLite]" for
2924** additional information.
2925**
2926** [[URI filename examples]] <h3>URI filename examples</h3>
2927**
2928** <table border="1" align=center cellpadding=5>
2929** <tr><th> URI filenames <th> Results
2930** <tr><td> file:data.db <td>
2931**          Open the file "data.db" in the current directory.
2932** <tr><td> file:/home/fred/data.db<br>
2933**          file:///home/fred/data.db <br>
2934**          file://localhost/home/fred/data.db <br> <td>
2935**          Open the database file "/home/fred/data.db".
2936** <tr><td> file://darkstar/home/fred/data.db <td>
2937**          An error. "darkstar" is not a recognized authority.
2938** <tr><td style="white-space:nowrap">
2939**          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
2940**     <td> Windows only: Open the file "data.db" on fred's desktop on drive
2941**          C:. Note that the %20 escaping in this example is not strictly
2942**          necessary - space characters can be used literally
2943**          in URI filenames.
2944** <tr><td> file:data.db?mode=ro&cache=private <td>
2945**          Open file "data.db" in the current directory for read-only access.
2946**          Regardless of whether or not shared-cache mode is enabled by
2947**          default, use a private cache.
2948** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
2949**          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
2950**          that uses dot-files in place of posix advisory locking.
2951** <tr><td> file:data.db?mode=readonly <td>
2952**          An error. "readonly" is not a valid option for the "mode" parameter.
2953** </table>
2954**
2955** ^URI hexadecimal escape sequences (%HH) are supported within the path and
2956** query components of a URI. A hexadecimal escape sequence consists of a
2957** percent sign - "%" - followed by exactly two hexadecimal digits
2958** specifying an octet value. ^Before the path or query components of a
2959** URI filename are interpreted, they are encoded using UTF-8 and all
2960** hexadecimal escape sequences replaced by a single byte containing the
2961** corresponding octet. If this process generates an invalid UTF-8 encoding,
2962** the results are undefined.
2963**
2964** <b>Note to Windows users:</b>  The encoding used for the filename argument
2965** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2966** codepage is currently defined.  Filenames containing international
2967** characters must be converted to UTF-8 prior to passing them into
2968** sqlite3_open() or sqlite3_open_v2().
2969**
2970** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
2971** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
2972** features that require the use of temporary files may fail.
2973**
2974** See also: [sqlite3_temp_directory]
2975*/
2976SQLITE_API int sqlite3_open(
2977  const char *filename,   /* Database filename (UTF-8) */
2978  sqlite3 **ppDb          /* OUT: SQLite db handle */
2979);
2980SQLITE_API int sqlite3_open16(
2981  const void *filename,   /* Database filename (UTF-16) */
2982  sqlite3 **ppDb          /* OUT: SQLite db handle */
2983);
2984SQLITE_API int sqlite3_open_v2(
2985  const char *filename,   /* Database filename (UTF-8) */
2986  sqlite3 **ppDb,         /* OUT: SQLite db handle */
2987  int flags,              /* Flags */
2988  const char *zVfs        /* Name of VFS module to use */
2989);
2990
2991/*
2992** CAPI3REF: Obtain Values For URI Parameters
2993**
2994** These are utility routines, useful to VFS implementations, that check
2995** to see if a database file was a URI that contained a specific query
2996** parameter, and if so obtains the value of that query parameter.
2997**
2998** If F is the database filename pointer passed into the xOpen() method of
2999** a VFS implementation when the flags parameter to xOpen() has one or
3000** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
3001** P is the name of the query parameter, then
3002** sqlite3_uri_parameter(F,P) returns the value of the P
3003** parameter if it exists or a NULL pointer if P does not appear as a
3004** query parameter on F.  If P is a query parameter of F
3005** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3006** a pointer to an empty string.
3007**
3008** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3009** parameter and returns true (1) or false (0) according to the value
3010** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3011** value of query parameter P is one of "yes", "true", or "on" in any
3012** case or if the value begins with a non-zero number.  The
3013** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3014** query parameter P is one of "no", "false", or "off" in any case or
3015** if the value begins with a numeric zero.  If P is not a query
3016** parameter on F or if the value of P is does not match any of the
3017** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3018**
3019** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3020** 64-bit signed integer and returns that integer, or D if P does not
3021** exist.  If the value of P is something other than an integer, then
3022** zero is returned.
3023**
3024** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3025** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
3026** is not a database file pathname pointer that SQLite passed into the xOpen
3027** VFS method, then the behavior of this routine is undefined and probably
3028** undesirable.
3029*/
3030SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3031SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3032SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3033
3034
3035/*
3036** CAPI3REF: Error Codes And Messages
3037**
3038** ^The sqlite3_errcode() interface returns the numeric [result code] or
3039** [extended result code] for the most recent failed sqlite3_* API call
3040** associated with a [database connection]. If a prior API call failed
3041** but the most recent API call succeeded, the return value from
3042** sqlite3_errcode() is undefined.  ^The sqlite3_extended_errcode()
3043** interface is the same except that it always returns the
3044** [extended result code] even when extended result codes are
3045** disabled.
3046**
3047** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3048** text that describes the error, as either UTF-8 or UTF-16 respectively.
3049** ^(Memory to hold the error message string is managed internally.
3050** The application does not need to worry about freeing the result.
3051** However, the error string might be overwritten or deallocated by
3052** subsequent calls to other SQLite interface functions.)^
3053**
3054** ^The sqlite3_errstr() interface returns the English-language text
3055** that describes the [result code], as UTF-8.
3056** ^(Memory to hold the error message string is managed internally
3057** and must not be freed by the application)^.
3058**
3059** When the serialized [threading mode] is in use, it might be the
3060** case that a second error occurs on a separate thread in between
3061** the time of the first error and the call to these interfaces.
3062** When that happens, the second error will be reported since these
3063** interfaces always report the most recent result.  To avoid
3064** this, each thread can obtain exclusive use of the [database connection] D
3065** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3066** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3067** all calls to the interfaces listed here are completed.
3068**
3069** If an interface fails with SQLITE_MISUSE, that means the interface
3070** was invoked incorrectly by the application.  In that case, the
3071** error code and message may or may not be set.
3072*/
3073SQLITE_API int sqlite3_errcode(sqlite3 *db);
3074SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
3075SQLITE_API const char *sqlite3_errmsg(sqlite3*);
3076SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
3077SQLITE_API const char *sqlite3_errstr(int);
3078
3079/*
3080** CAPI3REF: SQL Statement Object
3081** KEYWORDS: {prepared statement} {prepared statements}
3082**
3083** An instance of this object represents a single SQL statement.
3084** This object is variously known as a "prepared statement" or a
3085** "compiled SQL statement" or simply as a "statement".
3086**
3087** The life of a statement object goes something like this:
3088**
3089** <ol>
3090** <li> Create the object using [sqlite3_prepare_v2()] or a related
3091**      function.
3092** <li> Bind values to [host parameters] using the sqlite3_bind_*()
3093**      interfaces.
3094** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3095** <li> Reset the statement using [sqlite3_reset()] then go back
3096**      to step 2.  Do this zero or more times.
3097** <li> Destroy the object using [sqlite3_finalize()].
3098** </ol>
3099**
3100** Refer to documentation on individual methods above for additional
3101** information.
3102*/
3103typedef struct sqlite3_stmt sqlite3_stmt;
3104
3105/*
3106** CAPI3REF: Run-time Limits
3107**
3108** ^(This interface allows the size of various constructs to be limited
3109** on a connection by connection basis.  The first parameter is the
3110** [database connection] whose limit is to be set or queried.  The
3111** second parameter is one of the [limit categories] that define a
3112** class of constructs to be size limited.  The third parameter is the
3113** new limit for that construct.)^
3114**
3115** ^If the new limit is a negative number, the limit is unchanged.
3116** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3117** [limits | hard upper bound]
3118** set at compile-time by a C preprocessor macro called
3119** [limits | SQLITE_MAX_<i>NAME</i>].
3120** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3121** ^Attempts to increase a limit above its hard upper bound are
3122** silently truncated to the hard upper bound.
3123**
3124** ^Regardless of whether or not the limit was changed, the
3125** [sqlite3_limit()] interface returns the prior value of the limit.
3126** ^Hence, to find the current value of a limit without changing it,
3127** simply invoke this interface with the third parameter set to -1.
3128**
3129** Run-time limits are intended for use in applications that manage
3130** both their own internal database and also databases that are controlled
3131** by untrusted external sources.  An example application might be a
3132** web browser that has its own databases for storing history and
3133** separate databases controlled by JavaScript applications downloaded
3134** off the Internet.  The internal databases can be given the
3135** large, default limits.  Databases managed by external sources can
3136** be given much smaller limits designed to prevent a denial of service
3137** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
3138** interface to further control untrusted SQL.  The size of the database
3139** created by an untrusted script can be contained using the
3140** [max_page_count] [PRAGMA].
3141**
3142** New run-time limit categories may be added in future releases.
3143*/
3144SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
3145
3146/*
3147** CAPI3REF: Run-Time Limit Categories
3148** KEYWORDS: {limit category} {*limit categories}
3149**
3150** These constants define various performance limits
3151** that can be lowered at run-time using [sqlite3_limit()].
3152** The synopsis of the meanings of the various limits is shown below.
3153** Additional information is available at [limits | Limits in SQLite].
3154**
3155** <dl>
3156** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3157** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3158**
3159** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3160** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3161**
3162** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3163** <dd>The maximum number of columns in a table definition or in the
3164** result set of a [SELECT] or the maximum number of columns in an index
3165** or in an ORDER BY or GROUP BY clause.</dd>)^
3166**
3167** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3168** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3169**
3170** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3171** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3172**
3173** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3174** <dd>The maximum number of instructions in a virtual machine program
3175** used to implement an SQL statement.  This limit is not currently
3176** enforced, though that might be added in some future release of
3177** SQLite.</dd>)^
3178**
3179** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3180** <dd>The maximum number of arguments on a function.</dd>)^
3181**
3182** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3183** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3184**
3185** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3186** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3187** <dd>The maximum length of the pattern argument to the [LIKE] or
3188** [GLOB] operators.</dd>)^
3189**
3190** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3191** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3192** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3193**
3194** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3195** <dd>The maximum depth of recursion for triggers.</dd>)^
3196** </dl>
3197*/
3198#define SQLITE_LIMIT_LENGTH                    0
3199#define SQLITE_LIMIT_SQL_LENGTH                1
3200#define SQLITE_LIMIT_COLUMN                    2
3201#define SQLITE_LIMIT_EXPR_DEPTH                3
3202#define SQLITE_LIMIT_COMPOUND_SELECT           4
3203#define SQLITE_LIMIT_VDBE_OP                   5
3204#define SQLITE_LIMIT_FUNCTION_ARG              6
3205#define SQLITE_LIMIT_ATTACHED                  7
3206#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
3207#define SQLITE_LIMIT_VARIABLE_NUMBER           9
3208#define SQLITE_LIMIT_TRIGGER_DEPTH            10
3209
3210/*
3211** CAPI3REF: Compiling An SQL Statement
3212** KEYWORDS: {SQL statement compiler}
3213**
3214** To execute an SQL query, it must first be compiled into a byte-code
3215** program using one of these routines.
3216**
3217** The first argument, "db", is a [database connection] obtained from a
3218** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3219** [sqlite3_open16()].  The database connection must not have been closed.
3220**
3221** The second argument, "zSql", is the statement to be compiled, encoded
3222** as either UTF-8 or UTF-16.  The sqlite3_prepare() and sqlite3_prepare_v2()
3223** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
3224** use UTF-16.
3225**
3226** ^If the nByte argument is less than zero, then zSql is read up to the
3227** first zero terminator. ^If nByte is non-negative, then it is the maximum
3228** number of  bytes read from zSql.  ^When nByte is non-negative, the
3229** zSql string ends at either the first '\000' or '\u0000' character or
3230** the nByte-th byte, whichever comes first. If the caller knows
3231** that the supplied string is nul-terminated, then there is a small
3232** performance advantage to be gained by passing an nByte parameter that
3233** is equal to the number of bytes in the input string <i>including</i>
3234** the nul-terminator bytes as this saves SQLite from having to
3235** make a copy of the input string.
3236**
3237** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3238** past the end of the first SQL statement in zSql.  These routines only
3239** compile the first statement in zSql, so *pzTail is left pointing to
3240** what remains uncompiled.
3241**
3242** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3243** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
3244** to NULL.  ^If the input text contains no SQL (if the input is an empty
3245** string or a comment) then *ppStmt is set to NULL.
3246** The calling procedure is responsible for deleting the compiled
3247** SQL statement using [sqlite3_finalize()] after it has finished with it.
3248** ppStmt may not be NULL.
3249**
3250** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3251** otherwise an [error code] is returned.
3252**
3253** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
3254** recommended for all new programs. The two older interfaces are retained
3255** for backwards compatibility, but their use is discouraged.
3256** ^In the "v2" interfaces, the prepared statement
3257** that is returned (the [sqlite3_stmt] object) contains a copy of the
3258** original SQL text. This causes the [sqlite3_step()] interface to
3259** behave differently in three ways:
3260**
3261** <ol>
3262** <li>
3263** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3264** always used to do, [sqlite3_step()] will automatically recompile the SQL
3265** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3266** retries will occur before sqlite3_step() gives up and returns an error.
3267** </li>
3268**
3269** <li>
3270** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3271** [error codes] or [extended error codes].  ^The legacy behavior was that
3272** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3273** and the application would have to make a second call to [sqlite3_reset()]
3274** in order to find the underlying cause of the problem. With the "v2" prepare
3275** interfaces, the underlying reason for the error is returned immediately.
3276** </li>
3277**
3278** <li>
3279** ^If the specific value bound to [parameter | host parameter] in the
3280** WHERE clause might influence the choice of query plan for a statement,
3281** then the statement will be automatically recompiled, as if there had been
3282** a schema change, on the first  [sqlite3_step()] call following any change
3283** to the [sqlite3_bind_text | bindings] of that [parameter].
3284** ^The specific value of WHERE-clause [parameter] might influence the
3285** choice of query plan if the parameter is the left-hand side of a [LIKE]
3286** or [GLOB] operator or if the parameter is compared to an indexed column
3287** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3288** </li>
3289** </ol>
3290*/
3291SQLITE_API int sqlite3_prepare(
3292  sqlite3 *db,            /* Database handle */
3293  const char *zSql,       /* SQL statement, UTF-8 encoded */
3294  int nByte,              /* Maximum length of zSql in bytes. */
3295  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3296  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
3297);
3298SQLITE_API int sqlite3_prepare_v2(
3299  sqlite3 *db,            /* Database handle */
3300  const char *zSql,       /* SQL statement, UTF-8 encoded */
3301  int nByte,              /* Maximum length of zSql in bytes. */
3302  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3303  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
3304);
3305SQLITE_API int sqlite3_prepare16(
3306  sqlite3 *db,            /* Database handle */
3307  const void *zSql,       /* SQL statement, UTF-16 encoded */
3308  int nByte,              /* Maximum length of zSql in bytes. */
3309  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3310  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
3311);
3312SQLITE_API int sqlite3_prepare16_v2(
3313  sqlite3 *db,            /* Database handle */
3314  const void *zSql,       /* SQL statement, UTF-16 encoded */
3315  int nByte,              /* Maximum length of zSql in bytes. */
3316  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3317  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
3318);
3319
3320/*
3321** CAPI3REF: Retrieving Statement SQL
3322**
3323** ^This interface can be used to retrieve a saved copy of the original
3324** SQL text used to create a [prepared statement] if that statement was
3325** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
3326*/
3327SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
3328
3329/*
3330** CAPI3REF: Determine If An SQL Statement Writes The Database
3331**
3332** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3333** and only if the [prepared statement] X makes no direct changes to
3334** the content of the database file.
3335**
3336** Note that [application-defined SQL functions] or
3337** [virtual tables] might change the database indirectly as a side effect.
3338** ^(For example, if an application defines a function "eval()" that
3339** calls [sqlite3_exec()], then the following SQL statement would
3340** change the database file through side-effects:
3341**
3342** <blockquote><pre>
3343**    SELECT eval('DELETE FROM t1') FROM t2;
3344** </pre></blockquote>
3345**
3346** But because the [SELECT] statement does not change the database file
3347** directly, sqlite3_stmt_readonly() would still return true.)^
3348**
3349** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3350** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3351** since the statements themselves do not actually modify the database but
3352** rather they control the timing of when other statements modify the
3353** database.  ^The [ATTACH] and [DETACH] statements also cause
3354** sqlite3_stmt_readonly() to return true since, while those statements
3355** change the configuration of a database connection, they do not make
3356** changes to the content of the database files on disk.
3357*/
3358SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3359
3360/*
3361** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3362**
3363** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3364** [prepared statement] S has been stepped at least once using
3365** [sqlite3_step(S)] but has not run to completion and/or has not
3366** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
3367** interface returns false if S is a NULL pointer.  If S is not a
3368** NULL pointer and is not a pointer to a valid [prepared statement]
3369** object, then the behavior is undefined and probably undesirable.
3370**
3371** This interface can be used in combination [sqlite3_next_stmt()]
3372** to locate all prepared statements associated with a database
3373** connection that are in need of being reset.  This can be used,
3374** for example, in diagnostic routines to search for prepared
3375** statements that are holding a transaction open.
3376*/
3377SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
3378
3379/*
3380** CAPI3REF: Dynamically Typed Value Object
3381** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3382**
3383** SQLite uses the sqlite3_value object to represent all values
3384** that can be stored in a database table. SQLite uses dynamic typing
3385** for the values it stores.  ^Values stored in sqlite3_value objects
3386** can be integers, floating point values, strings, BLOBs, or NULL.
3387**
3388** An sqlite3_value object may be either "protected" or "unprotected".
3389** Some interfaces require a protected sqlite3_value.  Other interfaces
3390** will accept either a protected or an unprotected sqlite3_value.
3391** Every interface that accepts sqlite3_value arguments specifies
3392** whether or not it requires a protected sqlite3_value.
3393**
3394** The terms "protected" and "unprotected" refer to whether or not
3395** a mutex is held.  An internal mutex is held for a protected
3396** sqlite3_value object but no mutex is held for an unprotected
3397** sqlite3_value object.  If SQLite is compiled to be single-threaded
3398** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3399** or if SQLite is run in one of reduced mutex modes
3400** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3401** then there is no distinction between protected and unprotected
3402** sqlite3_value objects and they can be used interchangeably.  However,
3403** for maximum code portability it is recommended that applications
3404** still make the distinction between protected and unprotected
3405** sqlite3_value objects even when not strictly required.
3406**
3407** ^The sqlite3_value objects that are passed as parameters into the
3408** implementation of [application-defined SQL functions] are protected.
3409** ^The sqlite3_value object returned by
3410** [sqlite3_column_value()] is unprotected.
3411** Unprotected sqlite3_value objects may only be used with
3412** [sqlite3_result_value()] and [sqlite3_bind_value()].
3413** The [sqlite3_value_blob | sqlite3_value_type()] family of
3414** interfaces require protected sqlite3_value objects.
3415*/
3416typedef struct Mem sqlite3_value;
3417
3418/*
3419** CAPI3REF: SQL Function Context Object
3420**
3421** The context in which an SQL function executes is stored in an
3422** sqlite3_context object.  ^A pointer to an sqlite3_context object
3423** is always first parameter to [application-defined SQL functions].
3424** The application-defined SQL function implementation will pass this
3425** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3426** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3427** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3428** and/or [sqlite3_set_auxdata()].
3429*/
3430typedef struct sqlite3_context sqlite3_context;
3431
3432/*
3433** CAPI3REF: Binding Values To Prepared Statements
3434** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3435** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3436**
3437** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3438** literals may be replaced by a [parameter] that matches one of following
3439** templates:
3440**
3441** <ul>
3442** <li>  ?
3443** <li>  ?NNN
3444** <li>  :VVV
3445** <li>  @VVV
3446** <li>  $VVV
3447** </ul>
3448**
3449** In the templates above, NNN represents an integer literal,
3450** and VVV represents an alphanumeric identifier.)^  ^The values of these
3451** parameters (also called "host parameter names" or "SQL parameters")
3452** can be set using the sqlite3_bind_*() routines defined here.
3453**
3454** ^The first argument to the sqlite3_bind_*() routines is always
3455** a pointer to the [sqlite3_stmt] object returned from
3456** [sqlite3_prepare_v2()] or its variants.
3457**
3458** ^The second argument is the index of the SQL parameter to be set.
3459** ^The leftmost SQL parameter has an index of 1.  ^When the same named
3460** SQL parameter is used more than once, second and subsequent
3461** occurrences have the same index as the first occurrence.
3462** ^The index for named parameters can be looked up using the
3463** [sqlite3_bind_parameter_index()] API if desired.  ^The index
3464** for "?NNN" parameters is the value of NNN.
3465** ^The NNN value must be between 1 and the [sqlite3_limit()]
3466** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3467**
3468** ^The third argument is the value to bind to the parameter.
3469** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3470** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3471** is ignored and the end result is the same as sqlite3_bind_null().
3472**
3473** ^(In those routines that have a fourth argument, its value is the
3474** number of bytes in the parameter.  To be clear: the value is the
3475** number of <u>bytes</u> in the value, not the number of characters.)^
3476** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3477** is negative, then the length of the string is
3478** the number of bytes up to the first zero terminator.
3479** If the fourth parameter to sqlite3_bind_blob() is negative, then
3480** the behavior is undefined.
3481** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3482** or sqlite3_bind_text16() then that parameter must be the byte offset
3483** where the NUL terminator would occur assuming the string were NUL
3484** terminated.  If any NUL characters occur at byte offsets less than
3485** the value of the fourth parameter then the resulting string value will
3486** contain embedded NULs.  The result of expressions involving strings
3487** with embedded NULs is undefined.
3488**
3489** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
3490** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
3491** string after SQLite has finished with it.  ^The destructor is called
3492** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(),
3493** sqlite3_bind_text(), or sqlite3_bind_text16() fails.
3494** ^If the fifth argument is
3495** the special value [SQLITE_STATIC], then SQLite assumes that the
3496** information is in static, unmanaged space and does not need to be freed.
3497** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3498** SQLite makes its own private copy of the data immediately, before
3499** the sqlite3_bind_*() routine returns.
3500**
3501** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3502** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
3503** (just an integer to hold its size) while it is being processed.
3504** Zeroblobs are intended to serve as placeholders for BLOBs whose
3505** content is later written using
3506** [sqlite3_blob_open | incremental BLOB I/O] routines.
3507** ^A negative value for the zeroblob results in a zero-length BLOB.
3508**
3509** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3510** for the [prepared statement] or with a prepared statement for which
3511** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3512** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
3513** routine is passed a [prepared statement] that has been finalized, the
3514** result is undefined and probably harmful.
3515**
3516** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3517** ^Unbound parameters are interpreted as NULL.
3518**
3519** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3520** [error code] if anything goes wrong.
3521** ^[SQLITE_RANGE] is returned if the parameter
3522** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
3523**
3524** See also: [sqlite3_bind_parameter_count()],
3525** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3526*/
3527SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3528SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
3529SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
3530SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3531SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
3532SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
3533SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3534SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3535SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3536
3537/*
3538** CAPI3REF: Number Of SQL Parameters
3539**
3540** ^This routine can be used to find the number of [SQL parameters]
3541** in a [prepared statement].  SQL parameters are tokens of the
3542** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3543** placeholders for values that are [sqlite3_bind_blob | bound]
3544** to the parameters at a later time.
3545**
3546** ^(This routine actually returns the index of the largest (rightmost)
3547** parameter. For all forms except ?NNN, this will correspond to the
3548** number of unique parameters.  If parameters of the ?NNN form are used,
3549** there may be gaps in the list.)^
3550**
3551** See also: [sqlite3_bind_blob|sqlite3_bind()],
3552** [sqlite3_bind_parameter_name()], and
3553** [sqlite3_bind_parameter_index()].
3554*/
3555SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
3556
3557/*
3558** CAPI3REF: Name Of A Host Parameter
3559**
3560** ^The sqlite3_bind_parameter_name(P,N) interface returns
3561** the name of the N-th [SQL parameter] in the [prepared statement] P.
3562** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3563** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3564** respectively.
3565** In other words, the initial ":" or "$" or "@" or "?"
3566** is included as part of the name.)^
3567** ^Parameters of the form "?" without a following integer have no name
3568** and are referred to as "nameless" or "anonymous parameters".
3569**
3570** ^The first host parameter has an index of 1, not 0.
3571**
3572** ^If the value N is out of range or if the N-th parameter is
3573** nameless, then NULL is returned.  ^The returned string is
3574** always in UTF-8 encoding even if the named parameter was
3575** originally specified as UTF-16 in [sqlite3_prepare16()] or
3576** [sqlite3_prepare16_v2()].
3577**
3578** See also: [sqlite3_bind_blob|sqlite3_bind()],
3579** [sqlite3_bind_parameter_count()], and
3580** [sqlite3_bind_parameter_index()].
3581*/
3582SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
3583
3584/*
3585** CAPI3REF: Index Of A Parameter With A Given Name
3586**
3587** ^Return the index of an SQL parameter given its name.  ^The
3588** index value returned is suitable for use as the second
3589** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
3590** is returned if no matching parameter is found.  ^The parameter
3591** name must be given in UTF-8 even if the original statement
3592** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3593**
3594** See also: [sqlite3_bind_blob|sqlite3_bind()],
3595** [sqlite3_bind_parameter_count()], and
3596** [sqlite3_bind_parameter_index()].
3597*/
3598SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
3599
3600/*
3601** CAPI3REF: Reset All Bindings On A Prepared Statement
3602**
3603** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3604** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3605** ^Use this routine to reset all host parameters to NULL.
3606*/
3607SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
3608
3609/*
3610** CAPI3REF: Number Of Columns In A Result Set
3611**
3612** ^Return the number of columns in the result set returned by the
3613** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3614** statement that does not return data (for example an [UPDATE]).
3615**
3616** See also: [sqlite3_data_count()]
3617*/
3618SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
3619
3620/*
3621** CAPI3REF: Column Names In A Result Set
3622**
3623** ^These routines return the name assigned to a particular column
3624** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
3625** interface returns a pointer to a zero-terminated UTF-8 string
3626** and sqlite3_column_name16() returns a pointer to a zero-terminated
3627** UTF-16 string.  ^The first parameter is the [prepared statement]
3628** that implements the [SELECT] statement. ^The second parameter is the
3629** column number.  ^The leftmost column is number 0.
3630**
3631** ^The returned string pointer is valid until either the [prepared statement]
3632** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3633** reprepared by the first call to [sqlite3_step()] for a particular run
3634** or until the next call to
3635** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3636**
3637** ^If sqlite3_malloc() fails during the processing of either routine
3638** (for example during a conversion from UTF-8 to UTF-16) then a
3639** NULL pointer is returned.
3640**
3641** ^The name of a result column is the value of the "AS" clause for
3642** that column, if there is an AS clause.  If there is no AS clause
3643** then the name of the column is unspecified and may change from
3644** one release of SQLite to the next.
3645*/
3646SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
3647SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
3648
3649/*
3650** CAPI3REF: Source Of Data In A Query Result
3651**
3652** ^These routines provide a means to determine the database, table, and
3653** table column that is the origin of a particular result column in
3654** [SELECT] statement.
3655** ^The name of the database or table or column can be returned as
3656** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
3657** the database name, the _table_ routines return the table name, and
3658** the origin_ routines return the column name.
3659** ^The returned string is valid until the [prepared statement] is destroyed
3660** using [sqlite3_finalize()] or until the statement is automatically
3661** reprepared by the first call to [sqlite3_step()] for a particular run
3662** or until the same information is requested
3663** again in a different encoding.
3664**
3665** ^The names returned are the original un-aliased names of the
3666** database, table, and column.
3667**
3668** ^The first argument to these interfaces is a [prepared statement].
3669** ^These functions return information about the Nth result column returned by
3670** the statement, where N is the second function argument.
3671** ^The left-most column is column 0 for these routines.
3672**
3673** ^If the Nth column returned by the statement is an expression or
3674** subquery and is not a column value, then all of these functions return
3675** NULL.  ^These routine might also return NULL if a memory allocation error
3676** occurs.  ^Otherwise, they return the name of the attached database, table,
3677** or column that query result column was extracted from.
3678**
3679** ^As with all other SQLite APIs, those whose names end with "16" return
3680** UTF-16 encoded strings and the other functions return UTF-8.
3681**
3682** ^These APIs are only available if the library was compiled with the
3683** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3684**
3685** If two or more threads call one or more of these routines against the same
3686** prepared statement and column at the same time then the results are
3687** undefined.
3688**
3689** If two or more threads call one or more
3690** [sqlite3_column_database_name | column metadata interfaces]
3691** for the same [prepared statement] and result column
3692** at the same time then the results are undefined.
3693*/
3694SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
3695SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
3696SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
3697SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
3698SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
3699SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
3700
3701/*
3702** CAPI3REF: Declared Datatype Of A Query Result
3703**
3704** ^(The first parameter is a [prepared statement].
3705** If this statement is a [SELECT] statement and the Nth column of the
3706** returned result set of that [SELECT] is a table column (not an
3707** expression or subquery) then the declared type of the table
3708** column is returned.)^  ^If the Nth column of the result set is an
3709** expression or subquery, then a NULL pointer is returned.
3710** ^The returned string is always UTF-8 encoded.
3711**
3712** ^(For example, given the database schema:
3713**
3714** CREATE TABLE t1(c1 VARIANT);
3715**
3716** and the following statement to be compiled:
3717**
3718** SELECT c1 + 1, c1 FROM t1;
3719**
3720** this routine would return the string "VARIANT" for the second result
3721** column (i==1), and a NULL pointer for the first result column (i==0).)^
3722**
3723** ^SQLite uses dynamic run-time typing.  ^So just because a column
3724** is declared to contain a particular type does not mean that the
3725** data stored in that column is of the declared type.  SQLite is
3726** strongly typed, but the typing is dynamic not static.  ^Type
3727** is associated with individual values, not with the containers
3728** used to hold those values.
3729*/
3730SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
3731SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
3732
3733/*
3734** CAPI3REF: Evaluate An SQL Statement
3735**
3736** After a [prepared statement] has been prepared using either
3737** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3738** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3739** must be called one or more times to evaluate the statement.
3740**
3741** The details of the behavior of the sqlite3_step() interface depend
3742** on whether the statement was prepared using the newer "v2" interface
3743** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3744** interface [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
3745** new "v2" interface is recommended for new applications but the legacy
3746** interface will continue to be supported.
3747**
3748** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3749** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3750** ^With the "v2" interface, any of the other [result codes] or
3751** [extended result codes] might be returned as well.
3752**
3753** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3754** database locks it needs to do its job.  ^If the statement is a [COMMIT]
3755** or occurs outside of an explicit transaction, then you can retry the
3756** statement.  If the statement is not a [COMMIT] and occurs within an
3757** explicit transaction then you should rollback the transaction before
3758** continuing.
3759**
3760** ^[SQLITE_DONE] means that the statement has finished executing
3761** successfully.  sqlite3_step() should not be called again on this virtual
3762** machine without first calling [sqlite3_reset()] to reset the virtual
3763** machine back to its initial state.
3764**
3765** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3766** is returned each time a new row of data is ready for processing by the
3767** caller. The values may be accessed using the [column access functions].
3768** sqlite3_step() is called again to retrieve the next row of data.
3769**
3770** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3771** violation) has occurred.  sqlite3_step() should not be called again on
3772** the VM. More information may be found by calling [sqlite3_errmsg()].
3773** ^With the legacy interface, a more specific error code (for example,
3774** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3775** can be obtained by calling [sqlite3_reset()] on the
3776** [prepared statement].  ^In the "v2" interface,
3777** the more specific error code is returned directly by sqlite3_step().
3778**
3779** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3780** Perhaps it was called on a [prepared statement] that has
3781** already been [sqlite3_finalize | finalized] or on one that had
3782** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
3783** be the case that the same database connection is being used by two or
3784** more threads at the same moment in time.
3785**
3786** For all versions of SQLite up to and including 3.6.23.1, a call to
3787** [sqlite3_reset()] was required after sqlite3_step() returned anything
3788** other than [SQLITE_ROW] before any subsequent invocation of
3789** sqlite3_step().  Failure to reset the prepared statement using
3790** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3791** sqlite3_step().  But after version 3.6.23.1, sqlite3_step() began
3792** calling [sqlite3_reset()] automatically in this circumstance rather
3793** than returning [SQLITE_MISUSE].  This is not considered a compatibility
3794** break because any application that ever receives an SQLITE_MISUSE error
3795** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
3796** can be used to restore the legacy behavior.
3797**
3798** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3799** API always returns a generic error code, [SQLITE_ERROR], following any
3800** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
3801** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3802** specific [error codes] that better describes the error.
3803** We admit that this is a goofy design.  The problem has been fixed
3804** with the "v2" interface.  If you prepare all of your SQL statements
3805** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3806** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3807** then the more specific [error codes] are returned directly
3808** by sqlite3_step().  The use of the "v2" interface is recommended.
3809*/
3810SQLITE_API int sqlite3_step(sqlite3_stmt*);
3811
3812/*
3813** CAPI3REF: Number of columns in a result set
3814**
3815** ^The sqlite3_data_count(P) interface returns the number of columns in the
3816** current row of the result set of [prepared statement] P.
3817** ^If prepared statement P does not have results ready to return
3818** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3819** interfaces) then sqlite3_data_count(P) returns 0.
3820** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3821** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
3822** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
3823** will return non-zero if previous call to [sqlite3_step](P) returned
3824** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
3825** where it always returns zero since each step of that multi-step
3826** pragma returns 0 columns of data.
3827**
3828** See also: [sqlite3_column_count()]
3829*/
3830SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
3831
3832/*
3833** CAPI3REF: Fundamental Datatypes
3834** KEYWORDS: SQLITE_TEXT
3835**
3836** ^(Every value in SQLite has one of five fundamental datatypes:
3837**
3838** <ul>
3839** <li> 64-bit signed integer
3840** <li> 64-bit IEEE floating point number
3841** <li> string
3842** <li> BLOB
3843** <li> NULL
3844** </ul>)^
3845**
3846** These constants are codes for each of those types.
3847**
3848** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3849** for a completely different meaning.  Software that links against both
3850** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3851** SQLITE_TEXT.
3852*/
3853#define SQLITE_INTEGER  1
3854#define SQLITE_FLOAT    2
3855#define SQLITE_BLOB     4
3856#define SQLITE_NULL     5
3857#ifdef SQLITE_TEXT
3858# undef SQLITE_TEXT
3859#else
3860# define SQLITE_TEXT     3
3861#endif
3862#define SQLITE3_TEXT     3
3863
3864/*
3865** CAPI3REF: Result Values From A Query
3866** KEYWORDS: {column access functions}
3867**
3868** These routines form the "result set" interface.
3869**
3870** ^These routines return information about a single column of the current
3871** result row of a query.  ^In every case the first argument is a pointer
3872** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3873** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3874** and the second argument is the index of the column for which information
3875** should be returned. ^The leftmost column of the result set has the index 0.
3876** ^The number of columns in the result can be determined using
3877** [sqlite3_column_count()].
3878**
3879** If the SQL statement does not currently point to a valid row, or if the
3880** column index is out of range, the result is undefined.
3881** These routines may only be called when the most recent call to
3882** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3883** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3884** If any of these routines are called after [sqlite3_reset()] or
3885** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3886** something other than [SQLITE_ROW], the results are undefined.
3887** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3888** are called from a different thread while any of these routines
3889** are pending, then the results are undefined.
3890**
3891** ^The sqlite3_column_type() routine returns the
3892** [SQLITE_INTEGER | datatype code] for the initial data type
3893** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
3894** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].  The value
3895** returned by sqlite3_column_type() is only meaningful if no type
3896** conversions have occurred as described below.  After a type conversion,
3897** the value returned by sqlite3_column_type() is undefined.  Future
3898** versions of SQLite may change the behavior of sqlite3_column_type()
3899** following a type conversion.
3900**
3901** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3902** routine returns the number of bytes in that BLOB or string.
3903** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3904** the string to UTF-8 and then returns the number of bytes.
3905** ^If the result is a numeric value then sqlite3_column_bytes() uses
3906** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3907** the number of bytes in that string.
3908** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3909**
3910** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3911** routine returns the number of bytes in that BLOB or string.
3912** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3913** the string to UTF-16 and then returns the number of bytes.
3914** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3915** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3916** the number of bytes in that string.
3917** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3918**
3919** ^The values returned by [sqlite3_column_bytes()] and
3920** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3921** of the string.  ^For clarity: the values returned by
3922** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3923** bytes in the string, not the number of characters.
3924**
3925** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3926** even empty strings, are always zero-terminated.  ^The return
3927** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3928**
3929** ^The object returned by [sqlite3_column_value()] is an
3930** [unprotected sqlite3_value] object.  An unprotected sqlite3_value object
3931** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
3932** If the [unprotected sqlite3_value] object returned by
3933** [sqlite3_column_value()] is used in any other way, including calls
3934** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3935** or [sqlite3_value_bytes()], then the behavior is undefined.
3936**
3937** These routines attempt to convert the value where appropriate.  ^For
3938** example, if the internal representation is FLOAT and a text result
3939** is requested, [sqlite3_snprintf()] is used internally to perform the
3940** conversion automatically.  ^(The following table details the conversions
3941** that are applied:
3942**
3943** <blockquote>
3944** <table border="1">
3945** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
3946**
3947** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
3948** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
3949** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
3950** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
3951** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
3952** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
3953** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
3954** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
3955** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
3956** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
3957** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
3958** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
3959** <tr><td>  TEXT    <td>   BLOB    <td> No change
3960** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
3961** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
3962** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
3963** </table>
3964** </blockquote>)^
3965**
3966** The table above makes reference to standard C library functions atoi()
3967** and atof().  SQLite does not really use these functions.  It has its
3968** own equivalent internal routines.  The atoi() and atof() names are
3969** used in the table for brevity and because they are familiar to most
3970** C programmers.
3971**
3972** Note that when type conversions occur, pointers returned by prior
3973** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
3974** sqlite3_column_text16() may be invalidated.
3975** Type conversions and pointer invalidations might occur
3976** in the following cases:
3977**
3978** <ul>
3979** <li> The initial content is a BLOB and sqlite3_column_text() or
3980**      sqlite3_column_text16() is called.  A zero-terminator might
3981**      need to be added to the string.</li>
3982** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
3983**      sqlite3_column_text16() is called.  The content must be converted
3984**      to UTF-16.</li>
3985** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
3986**      sqlite3_column_text() is called.  The content must be converted
3987**      to UTF-8.</li>
3988** </ul>
3989**
3990** ^Conversions between UTF-16be and UTF-16le are always done in place and do
3991** not invalidate a prior pointer, though of course the content of the buffer
3992** that the prior pointer references will have been modified.  Other kinds
3993** of conversion are done in place when it is possible, but sometimes they
3994** are not possible and in those cases prior pointers are invalidated.
3995**
3996** The safest and easiest to remember policy is to invoke these routines
3997** in one of the following ways:
3998**
3999** <ul>
4000**  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
4001**  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
4002**  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
4003** </ul>
4004**
4005** In other words, you should call sqlite3_column_text(),
4006** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
4007** into the desired format, then invoke sqlite3_column_bytes() or
4008** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
4009** to sqlite3_column_text() or sqlite3_column_blob() with calls to
4010** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
4011** with calls to sqlite3_column_bytes().
4012**
4013** ^The pointers returned are valid until a type conversion occurs as
4014** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
4015** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
4016** and BLOBs is freed automatically.  Do <b>not</b> pass the pointers returned
4017** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
4018** [sqlite3_free()].
4019**
4020** ^(If a memory allocation error occurs during the evaluation of any
4021** of these routines, a default value is returned.  The default value
4022** is either the integer 0, the floating point number 0.0, or a NULL
4023** pointer.  Subsequent calls to [sqlite3_errcode()] will return
4024** [SQLITE_NOMEM].)^
4025*/
4026SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
4027SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
4028SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
4029SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
4030SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
4031SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
4032SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
4033SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
4034SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
4035SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
4036
4037/*
4038** CAPI3REF: Destroy A Prepared Statement Object
4039**
4040** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4041** ^If the most recent evaluation of the statement encountered no errors
4042** or if the statement is never been evaluated, then sqlite3_finalize() returns
4043** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
4044** sqlite3_finalize(S) returns the appropriate [error code] or
4045** [extended error code].
4046**
4047** ^The sqlite3_finalize(S) routine can be called at any point during
4048** the life cycle of [prepared statement] S:
4049** before statement S is ever evaluated, after
4050** one or more calls to [sqlite3_reset()], or after any call
4051** to [sqlite3_step()] regardless of whether or not the statement has
4052** completed execution.
4053**
4054** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4055**
4056** The application must finalize every [prepared statement] in order to avoid
4057** resource leaks.  It is a grievous error for the application to try to use
4058** a prepared statement after it has been finalized.  Any use of a prepared
4059** statement after it has been finalized can result in undefined and
4060** undesirable behavior such as segfaults and heap corruption.
4061*/
4062SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
4063
4064/*
4065** CAPI3REF: Reset A Prepared Statement Object
4066**
4067** The sqlite3_reset() function is called to reset a [prepared statement]
4068** object back to its initial state, ready to be re-executed.
4069** ^Any SQL statement variables that had values bound to them using
4070** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4071** Use [sqlite3_clear_bindings()] to reset the bindings.
4072**
4073** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4074** back to the beginning of its program.
4075**
4076** ^If the most recent call to [sqlite3_step(S)] for the
4077** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4078** or if [sqlite3_step(S)] has never before been called on S,
4079** then [sqlite3_reset(S)] returns [SQLITE_OK].
4080**
4081** ^If the most recent call to [sqlite3_step(S)] for the
4082** [prepared statement] S indicated an error, then
4083** [sqlite3_reset(S)] returns an appropriate [error code].
4084**
4085** ^The [sqlite3_reset(S)] interface does not change the values
4086** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4087*/
4088SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
4089
4090/*
4091** CAPI3REF: Create Or Redefine SQL Functions
4092** KEYWORDS: {function creation routines}
4093** KEYWORDS: {application-defined SQL function}
4094** KEYWORDS: {application-defined SQL functions}
4095**
4096** ^These functions (collectively known as "function creation routines")
4097** are used to add SQL functions or aggregates or to redefine the behavior
4098** of existing SQL functions or aggregates.  The only differences between
4099** these routines are the text encoding expected for
4100** the second parameter (the name of the function being created)
4101** and the presence or absence of a destructor callback for
4102** the application data pointer.
4103**
4104** ^The first parameter is the [database connection] to which the SQL
4105** function is to be added.  ^If an application uses more than one database
4106** connection then application-defined SQL functions must be added
4107** to each database connection separately.
4108**
4109** ^The second parameter is the name of the SQL function to be created or
4110** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
4111** representation, exclusive of the zero-terminator.  ^Note that the name
4112** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4113** ^Any attempt to create a function with a longer name
4114** will result in [SQLITE_MISUSE] being returned.
4115**
4116** ^The third parameter (nArg)
4117** is the number of arguments that the SQL function or
4118** aggregate takes. ^If this parameter is -1, then the SQL function or
4119** aggregate may take any number of arguments between 0 and the limit
4120** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
4121** parameter is less than -1 or greater than 127 then the behavior is
4122** undefined.
4123**
4124** ^The fourth parameter, eTextRep, specifies what
4125** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4126** its parameters.  The application should set this parameter to
4127** [SQLITE_UTF16LE] if the function implementation invokes
4128** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4129** implementation invokes [sqlite3_value_text16be()] on an input, or
4130** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4131** otherwise.  ^The same SQL function may be registered multiple times using
4132** different preferred text encodings, with different implementations for
4133** each encoding.
4134** ^When multiple implementations of the same function are available, SQLite
4135** will pick the one that involves the least amount of data conversion.
4136**
4137** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4138** to signal that the function will always return the same result given
4139** the same inputs within a single SQL statement.  Most SQL functions are
4140** deterministic.  The built-in [random()] SQL function is an example of a
4141** function that is not deterministic.  The SQLite query planner is able to
4142** perform additional optimizations on deterministic functions, so use
4143** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4144**
4145** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
4146** function can gain access to this pointer using [sqlite3_user_data()].)^
4147**
4148** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
4149** pointers to C-language functions that implement the SQL function or
4150** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4151** callback only; NULL pointers must be passed as the xStep and xFinal
4152** parameters. ^An aggregate SQL function requires an implementation of xStep
4153** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4154** SQL function or aggregate, pass NULL pointers for all three function
4155** callbacks.
4156**
4157** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
4158** then it is destructor for the application data pointer.
4159** The destructor is invoked when the function is deleted, either by being
4160** overloaded or when the database connection closes.)^
4161** ^The destructor is also invoked if the call to
4162** sqlite3_create_function_v2() fails.
4163** ^When the destructor callback of the tenth parameter is invoked, it
4164** is passed a single argument which is a copy of the application data
4165** pointer which was the fifth parameter to sqlite3_create_function_v2().
4166**
4167** ^It is permitted to register multiple implementations of the same
4168** functions with the same name but with either differing numbers of
4169** arguments or differing preferred text encodings.  ^SQLite will use
4170** the implementation that most closely matches the way in which the
4171** SQL function is used.  ^A function implementation with a non-negative
4172** nArg parameter is a better match than a function implementation with
4173** a negative nArg.  ^A function where the preferred text encoding
4174** matches the database encoding is a better
4175** match than a function where the encoding is different.
4176** ^A function where the encoding difference is between UTF16le and UTF16be
4177** is a closer match than a function where the encoding difference is
4178** between UTF8 and UTF16.
4179**
4180** ^Built-in functions may be overloaded by new application-defined functions.
4181**
4182** ^An application-defined function is permitted to call other
4183** SQLite interfaces.  However, such calls must not
4184** close the database connection nor finalize or reset the prepared
4185** statement in which the function is running.
4186*/
4187SQLITE_API int sqlite3_create_function(
4188  sqlite3 *db,
4189  const char *zFunctionName,
4190  int nArg,
4191  int eTextRep,
4192  void *pApp,
4193  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4194  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4195  void (*xFinal)(sqlite3_context*)
4196);
4197SQLITE_API int sqlite3_create_function16(
4198  sqlite3 *db,
4199  const void *zFunctionName,
4200  int nArg,
4201  int eTextRep,
4202  void *pApp,
4203  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4204  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4205  void (*xFinal)(sqlite3_context*)
4206);
4207SQLITE_API int sqlite3_create_function_v2(
4208  sqlite3 *db,
4209  const char *zFunctionName,
4210  int nArg,
4211  int eTextRep,
4212  void *pApp,
4213  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4214  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4215  void (*xFinal)(sqlite3_context*),
4216  void(*xDestroy)(void*)
4217);
4218
4219/*
4220** CAPI3REF: Text Encodings
4221**
4222** These constant define integer codes that represent the various
4223** text encodings supported by SQLite.
4224*/
4225#define SQLITE_UTF8           1
4226#define SQLITE_UTF16LE        2
4227#define SQLITE_UTF16BE        3
4228#define SQLITE_UTF16          4    /* Use native byte order */
4229#define SQLITE_ANY            5    /* Deprecated */
4230#define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
4231
4232/*
4233** CAPI3REF: Function Flags
4234**
4235** These constants may be ORed together with the
4236** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4237** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4238** [sqlite3_create_function_v2()].
4239*/
4240#define SQLITE_DETERMINISTIC    0x800
4241
4242/*
4243** CAPI3REF: Deprecated Functions
4244** DEPRECATED
4245**
4246** These functions are [deprecated].  In order to maintain
4247** backwards compatibility with older code, these functions continue
4248** to be supported.  However, new applications should avoid
4249** the use of these functions.  To help encourage people to avoid
4250** using these functions, we are not going to tell you what they do.
4251*/
4252#ifndef SQLITE_OMIT_DEPRECATED
4253SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
4254SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
4255SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4256SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
4257SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
4258SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4259                      void*,sqlite3_int64);
4260#endif
4261
4262/*
4263** CAPI3REF: Obtaining SQL Function Parameter Values
4264**
4265** The C-language implementation of SQL functions and aggregates uses
4266** this set of interface routines to access the parameter values on
4267** the function or aggregate.
4268**
4269** The xFunc (for scalar functions) or xStep (for aggregates) parameters
4270** to [sqlite3_create_function()] and [sqlite3_create_function16()]
4271** define callbacks that implement the SQL functions and aggregates.
4272** The 3rd parameter to these callbacks is an array of pointers to
4273** [protected sqlite3_value] objects.  There is one [sqlite3_value] object for
4274** each parameter to the SQL function.  These routines are used to
4275** extract values from the [sqlite3_value] objects.
4276**
4277** These routines work only with [protected sqlite3_value] objects.
4278** Any attempt to use these routines on an [unprotected sqlite3_value]
4279** object results in undefined behavior.
4280**
4281** ^These routines work just like the corresponding [column access functions]
4282** except that  these routines take a single [protected sqlite3_value] object
4283** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4284**
4285** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4286** in the native byte-order of the host machine.  ^The
4287** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4288** extract UTF-16 strings as big-endian and little-endian respectively.
4289**
4290** ^(The sqlite3_value_numeric_type() interface attempts to apply
4291** numeric affinity to the value.  This means that an attempt is
4292** made to convert the value to an integer or floating point.  If
4293** such a conversion is possible without loss of information (in other
4294** words, if the value is a string that looks like a number)
4295** then the conversion is performed.  Otherwise no conversion occurs.
4296** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4297**
4298** Please pay particular attention to the fact that the pointer returned
4299** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4300** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4301** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4302** or [sqlite3_value_text16()].
4303**
4304** These routines must be called from the same thread as
4305** the SQL function that supplied the [sqlite3_value*] parameters.
4306*/
4307SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
4308SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
4309SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
4310SQLITE_API double sqlite3_value_double(sqlite3_value*);
4311SQLITE_API int sqlite3_value_int(sqlite3_value*);
4312SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
4313SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
4314SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
4315SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
4316SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
4317SQLITE_API int sqlite3_value_type(sqlite3_value*);
4318SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
4319
4320/*
4321** CAPI3REF: Obtain Aggregate Function Context
4322**
4323** Implementations of aggregate SQL functions use this
4324** routine to allocate memory for storing their state.
4325**
4326** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4327** for a particular aggregate function, SQLite
4328** allocates N of memory, zeroes out that memory, and returns a pointer
4329** to the new memory. ^On second and subsequent calls to
4330** sqlite3_aggregate_context() for the same aggregate function instance,
4331** the same buffer is returned.  Sqlite3_aggregate_context() is normally
4332** called once for each invocation of the xStep callback and then one
4333** last time when the xFinal callback is invoked.  ^(When no rows match
4334** an aggregate query, the xStep() callback of the aggregate function
4335** implementation is never called and xFinal() is called exactly once.
4336** In those cases, sqlite3_aggregate_context() might be called for the
4337** first time from within xFinal().)^
4338**
4339** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
4340** when first called if N is less than or equal to zero or if a memory
4341** allocate error occurs.
4342**
4343** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4344** determined by the N parameter on first successful call.  Changing the
4345** value of N in subsequent call to sqlite3_aggregate_context() within
4346** the same aggregate function instance will not resize the memory
4347** allocation.)^  Within the xFinal callback, it is customary to set
4348** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
4349** pointless memory allocations occur.
4350**
4351** ^SQLite automatically frees the memory allocated by
4352** sqlite3_aggregate_context() when the aggregate query concludes.
4353**
4354** The first parameter must be a copy of the
4355** [sqlite3_context | SQL function context] that is the first parameter
4356** to the xStep or xFinal callback routine that implements the aggregate
4357** function.
4358**
4359** This routine must be called from the same thread in which
4360** the aggregate SQL function is running.
4361*/
4362SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4363
4364/*
4365** CAPI3REF: User Data For Functions
4366**
4367** ^The sqlite3_user_data() interface returns a copy of
4368** the pointer that was the pUserData parameter (the 5th parameter)
4369** of the [sqlite3_create_function()]
4370** and [sqlite3_create_function16()] routines that originally
4371** registered the application defined function.
4372**
4373** This routine must be called from the same thread in which
4374** the application-defined function is running.
4375*/
4376SQLITE_API void *sqlite3_user_data(sqlite3_context*);
4377
4378/*
4379** CAPI3REF: Database Connection For Functions
4380**
4381** ^The sqlite3_context_db_handle() interface returns a copy of
4382** the pointer to the [database connection] (the 1st parameter)
4383** of the [sqlite3_create_function()]
4384** and [sqlite3_create_function16()] routines that originally
4385** registered the application defined function.
4386*/
4387SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
4388
4389/*
4390** CAPI3REF: Function Auxiliary Data
4391**
4392** These functions may be used by (non-aggregate) SQL functions to
4393** associate metadata with argument values. If the same value is passed to
4394** multiple invocations of the same SQL function during query execution, under
4395** some circumstances the associated metadata may be preserved.  An example
4396** of where this might be useful is in a regular-expression matching
4397** function. The compiled version of the regular expression can be stored as
4398** metadata associated with the pattern string.
4399** Then as long as the pattern string remains the same,
4400** the compiled regular expression can be reused on multiple
4401** invocations of the same function.
4402**
4403** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
4404** associated by the sqlite3_set_auxdata() function with the Nth argument
4405** value to the application-defined function. ^If there is no metadata
4406** associated with the function argument, this sqlite3_get_auxdata() interface
4407** returns a NULL pointer.
4408**
4409** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
4410** argument of the application-defined function.  ^Subsequent
4411** calls to sqlite3_get_auxdata(C,N) return P from the most recent
4412** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
4413** NULL if the metadata has been discarded.
4414** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
4415** SQLite will invoke the destructor function X with parameter P exactly
4416** once, when the metadata is discarded.
4417** SQLite is free to discard the metadata at any time, including: <ul>
4418** <li> when the corresponding function parameter changes, or
4419** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
4420**      SQL statement, or
4421** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or
4422** <li> during the original sqlite3_set_auxdata() call when a memory
4423**      allocation error occurs. </ul>)^
4424**
4425** Note the last bullet in particular.  The destructor X in
4426** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
4427** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
4428** should be called near the end of the function implementation and the
4429** function implementation should not make any use of P after
4430** sqlite3_set_auxdata() has been called.
4431**
4432** ^(In practice, metadata is preserved between function calls for
4433** function parameters that are compile-time constants, including literal
4434** values and [parameters] and expressions composed from the same.)^
4435**
4436** These routines must be called from the same thread in which
4437** the SQL function is running.
4438*/
4439SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
4440SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
4441
4442
4443/*
4444** CAPI3REF: Constants Defining Special Destructor Behavior
4445**
4446** These are special values for the destructor that is passed in as the
4447** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
4448** argument is SQLITE_STATIC, it means that the content pointer is constant
4449** and will never change.  It does not need to be destroyed.  ^The
4450** SQLITE_TRANSIENT value means that the content will likely change in
4451** the near future and that SQLite should make its own private copy of
4452** the content before returning.
4453**
4454** The typedef is necessary to work around problems in certain
4455** C++ compilers.
4456*/
4457typedef void (*sqlite3_destructor_type)(void*);
4458#define SQLITE_STATIC      ((sqlite3_destructor_type)0)
4459#define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
4460
4461/*
4462** CAPI3REF: Setting The Result Of An SQL Function
4463**
4464** These routines are used by the xFunc or xFinal callbacks that
4465** implement SQL functions and aggregates.  See
4466** [sqlite3_create_function()] and [sqlite3_create_function16()]
4467** for additional information.
4468**
4469** These functions work very much like the [parameter binding] family of
4470** functions used to bind values to host parameters in prepared statements.
4471** Refer to the [SQL parameter] documentation for additional information.
4472**
4473** ^The sqlite3_result_blob() interface sets the result from
4474** an application-defined function to be the BLOB whose content is pointed
4475** to by the second parameter and which is N bytes long where N is the
4476** third parameter.
4477**
4478** ^The sqlite3_result_zeroblob() interfaces set the result of
4479** the application-defined function to be a BLOB containing all zero
4480** bytes and N bytes in size, where N is the value of the 2nd parameter.
4481**
4482** ^The sqlite3_result_double() interface sets the result from
4483** an application-defined function to be a floating point value specified
4484** by its 2nd argument.
4485**
4486** ^The sqlite3_result_error() and sqlite3_result_error16() functions
4487** cause the implemented SQL function to throw an exception.
4488** ^SQLite uses the string pointed to by the
4489** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
4490** as the text of an error message.  ^SQLite interprets the error
4491** message string from sqlite3_result_error() as UTF-8. ^SQLite
4492** interprets the string from sqlite3_result_error16() as UTF-16 in native
4493** byte order.  ^If the third parameter to sqlite3_result_error()
4494** or sqlite3_result_error16() is negative then SQLite takes as the error
4495** message all text up through the first zero character.
4496** ^If the third parameter to sqlite3_result_error() or
4497** sqlite3_result_error16() is non-negative then SQLite takes that many
4498** bytes (not characters) from the 2nd parameter as the error message.
4499** ^The sqlite3_result_error() and sqlite3_result_error16()
4500** routines make a private copy of the error message text before
4501** they return.  Hence, the calling function can deallocate or
4502** modify the text after they return without harm.
4503** ^The sqlite3_result_error_code() function changes the error code
4504** returned by SQLite as a result of an error in a function.  ^By default,
4505** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
4506** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
4507**
4508** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
4509** error indicating that a string or BLOB is too long to represent.
4510**
4511** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
4512** error indicating that a memory allocation failed.
4513**
4514** ^The sqlite3_result_int() interface sets the return value
4515** of the application-defined function to be the 32-bit signed integer
4516** value given in the 2nd argument.
4517** ^The sqlite3_result_int64() interface sets the return value
4518** of the application-defined function to be the 64-bit signed integer
4519** value given in the 2nd argument.
4520**
4521** ^The sqlite3_result_null() interface sets the return value
4522** of the application-defined function to be NULL.
4523**
4524** ^The sqlite3_result_text(), sqlite3_result_text16(),
4525** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
4526** set the return value of the application-defined function to be
4527** a text string which is represented as UTF-8, UTF-16 native byte order,
4528** UTF-16 little endian, or UTF-16 big endian, respectively.
4529** ^SQLite takes the text result from the application from
4530** the 2nd parameter of the sqlite3_result_text* interfaces.
4531** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4532** is negative, then SQLite takes result text from the 2nd parameter
4533** through the first zero character.
4534** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4535** is non-negative, then as many bytes (not characters) of the text
4536** pointed to by the 2nd parameter are taken as the application-defined
4537** function result.  If the 3rd parameter is non-negative, then it
4538** must be the byte offset into the string where the NUL terminator would
4539** appear if the string where NUL terminated.  If any NUL characters occur
4540** in the string at a byte offset that is less than the value of the 3rd
4541** parameter, then the resulting string will contain embedded NULs and the
4542** result of expressions operating on strings with embedded NULs is undefined.
4543** ^If the 4th parameter to the sqlite3_result_text* interfaces
4544** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4545** function as the destructor on the text or BLOB result when it has
4546** finished using that result.
4547** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4548** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4549** assumes that the text or BLOB result is in constant space and does not
4550** copy the content of the parameter nor call a destructor on the content
4551** when it has finished using that result.
4552** ^If the 4th parameter to the sqlite3_result_text* interfaces
4553** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4554** then SQLite makes a copy of the result into space obtained from
4555** from [sqlite3_malloc()] before it returns.
4556**
4557** ^The sqlite3_result_value() interface sets the result of
4558** the application-defined function to be a copy the
4559** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
4560** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4561** so that the [sqlite3_value] specified in the parameter may change or
4562** be deallocated after sqlite3_result_value() returns without harm.
4563** ^A [protected sqlite3_value] object may always be used where an
4564** [unprotected sqlite3_value] object is required, so either
4565** kind of [sqlite3_value] object can be used with this interface.
4566**
4567** If these routines are called from within the different thread
4568** than the one containing the application-defined function that received
4569** the [sqlite3_context] pointer, the results are undefined.
4570*/
4571SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4572SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
4573SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
4574SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
4575SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
4576SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
4577SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
4578SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
4579SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4580SQLITE_API void sqlite3_result_null(sqlite3_context*);
4581SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4582SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4583SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4584SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4585SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4586SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
4587
4588/*
4589** CAPI3REF: Define New Collating Sequences
4590**
4591** ^These functions add, remove, or modify a [collation] associated
4592** with the [database connection] specified as the first argument.
4593**
4594** ^The name of the collation is a UTF-8 string
4595** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4596** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4597** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4598** considered to be the same name.
4599**
4600** ^(The third argument (eTextRep) must be one of the constants:
4601** <ul>
4602** <li> [SQLITE_UTF8],
4603** <li> [SQLITE_UTF16LE],
4604** <li> [SQLITE_UTF16BE],
4605** <li> [SQLITE_UTF16], or
4606** <li> [SQLITE_UTF16_ALIGNED].
4607** </ul>)^
4608** ^The eTextRep argument determines the encoding of strings passed
4609** to the collating function callback, xCallback.
4610** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4611** force strings to be UTF16 with native byte order.
4612** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4613** on an even byte address.
4614**
4615** ^The fourth argument, pArg, is an application data pointer that is passed
4616** through as the first argument to the collating function callback.
4617**
4618** ^The fifth argument, xCallback, is a pointer to the collating function.
4619** ^Multiple collating functions can be registered using the same name but
4620** with different eTextRep parameters and SQLite will use whichever
4621** function requires the least amount of data transformation.
4622** ^If the xCallback argument is NULL then the collating function is
4623** deleted.  ^When all collating functions having the same name are deleted,
4624** that collation is no longer usable.
4625**
4626** ^The collating function callback is invoked with a copy of the pArg
4627** application data pointer and with two strings in the encoding specified
4628** by the eTextRep argument.  The collating function must return an
4629** integer that is negative, zero, or positive
4630** if the first string is less than, equal to, or greater than the second,
4631** respectively.  A collating function must always return the same answer
4632** given the same inputs.  If two or more collating functions are registered
4633** to the same collation name (using different eTextRep values) then all
4634** must give an equivalent answer when invoked with equivalent strings.
4635** The collating function must obey the following properties for all
4636** strings A, B, and C:
4637**
4638** <ol>
4639** <li> If A==B then B==A.
4640** <li> If A==B and B==C then A==C.
4641** <li> If A&lt;B THEN B&gt;A.
4642** <li> If A&lt;B and B&lt;C then A&lt;C.
4643** </ol>
4644**
4645** If a collating function fails any of the above constraints and that
4646** collating function is  registered and used, then the behavior of SQLite
4647** is undefined.
4648**
4649** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4650** with the addition that the xDestroy callback is invoked on pArg when
4651** the collating function is deleted.
4652** ^Collating functions are deleted when they are overridden by later
4653** calls to the collation creation functions or when the
4654** [database connection] is closed using [sqlite3_close()].
4655**
4656** ^The xDestroy callback is <u>not</u> called if the
4657** sqlite3_create_collation_v2() function fails.  Applications that invoke
4658** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4659** check the return code and dispose of the application data pointer
4660** themselves rather than expecting SQLite to deal with it for them.
4661** This is different from every other SQLite interface.  The inconsistency
4662** is unfortunate but cannot be changed without breaking backwards
4663** compatibility.
4664**
4665** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4666*/
4667SQLITE_API int sqlite3_create_collation(
4668  sqlite3*,
4669  const char *zName,
4670  int eTextRep,
4671  void *pArg,
4672  int(*xCompare)(void*,int,const void*,int,const void*)
4673);
4674SQLITE_API int sqlite3_create_collation_v2(
4675  sqlite3*,
4676  const char *zName,
4677  int eTextRep,
4678  void *pArg,
4679  int(*xCompare)(void*,int,const void*,int,const void*),
4680  void(*xDestroy)(void*)
4681);
4682SQLITE_API int sqlite3_create_collation16(
4683  sqlite3*,
4684  const void *zName,
4685  int eTextRep,
4686  void *pArg,
4687  int(*xCompare)(void*,int,const void*,int,const void*)
4688);
4689
4690/*
4691** CAPI3REF: Collation Needed Callbacks
4692**
4693** ^To avoid having to register all collation sequences before a database
4694** can be used, a single callback function may be registered with the
4695** [database connection] to be invoked whenever an undefined collation
4696** sequence is required.
4697**
4698** ^If the function is registered using the sqlite3_collation_needed() API,
4699** then it is passed the names of undefined collation sequences as strings
4700** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4701** the names are passed as UTF-16 in machine native byte order.
4702** ^A call to either function replaces the existing collation-needed callback.
4703**
4704** ^(When the callback is invoked, the first argument passed is a copy
4705** of the second argument to sqlite3_collation_needed() or
4706** sqlite3_collation_needed16().  The second argument is the database
4707** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4708** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4709** sequence function required.  The fourth parameter is the name of the
4710** required collation sequence.)^
4711**
4712** The callback function should register the desired collation using
4713** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4714** [sqlite3_create_collation_v2()].
4715*/
4716SQLITE_API int sqlite3_collation_needed(
4717  sqlite3*,
4718  void*,
4719  void(*)(void*,sqlite3*,int eTextRep,const char*)
4720);
4721SQLITE_API int sqlite3_collation_needed16(
4722  sqlite3*,
4723  void*,
4724  void(*)(void*,sqlite3*,int eTextRep,const void*)
4725);
4726
4727#ifdef SQLITE_HAS_CODEC
4728/*
4729** Specify the key for an encrypted database.  This routine should be
4730** called right after sqlite3_open().
4731**
4732** The code to implement this API is not available in the public release
4733** of SQLite.
4734*/
4735SQLITE_API int sqlite3_key(
4736  sqlite3 *db,                   /* Database to be rekeyed */
4737  const void *pKey, int nKey     /* The key */
4738);
4739SQLITE_API int sqlite3_key_v2(
4740  sqlite3 *db,                   /* Database to be rekeyed */
4741  const char *zDbName,           /* Name of the database */
4742  const void *pKey, int nKey     /* The key */
4743);
4744
4745/*
4746** Change the key on an open database.  If the current database is not
4747** encrypted, this routine will encrypt it.  If pNew==0 or nNew==0, the
4748** database is decrypted.
4749**
4750** The code to implement this API is not available in the public release
4751** of SQLite.
4752*/
4753SQLITE_API int sqlite3_rekey(
4754  sqlite3 *db,                   /* Database to be rekeyed */
4755  const void *pKey, int nKey     /* The new key */
4756);
4757SQLITE_API int sqlite3_rekey_v2(
4758  sqlite3 *db,                   /* Database to be rekeyed */
4759  const char *zDbName,           /* Name of the database */
4760  const void *pKey, int nKey     /* The new key */
4761);
4762
4763/*
4764** Specify the activation key for a SEE database.  Unless
4765** activated, none of the SEE routines will work.
4766*/
4767SQLITE_API void sqlite3_activate_see(
4768  const char *zPassPhrase        /* Activation phrase */
4769);
4770#endif
4771
4772#ifdef SQLITE_ENABLE_CEROD
4773/*
4774** Specify the activation key for a CEROD database.  Unless
4775** activated, none of the CEROD routines will work.
4776*/
4777SQLITE_API void sqlite3_activate_cerod(
4778  const char *zPassPhrase        /* Activation phrase */
4779);
4780#endif
4781
4782/*
4783** CAPI3REF: Suspend Execution For A Short Time
4784**
4785** The sqlite3_sleep() function causes the current thread to suspend execution
4786** for at least a number of milliseconds specified in its parameter.
4787**
4788** If the operating system does not support sleep requests with
4789** millisecond time resolution, then the time will be rounded up to
4790** the nearest second. The number of milliseconds of sleep actually
4791** requested from the operating system is returned.
4792**
4793** ^SQLite implements this interface by calling the xSleep()
4794** method of the default [sqlite3_vfs] object.  If the xSleep() method
4795** of the default VFS is not implemented correctly, or not implemented at
4796** all, then the behavior of sqlite3_sleep() may deviate from the description
4797** in the previous paragraphs.
4798*/
4799SQLITE_API int sqlite3_sleep(int);
4800
4801/*
4802** CAPI3REF: Name Of The Folder Holding Temporary Files
4803**
4804** ^(If this global variable is made to point to a string which is
4805** the name of a folder (a.k.a. directory), then all temporary files
4806** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4807** will be placed in that directory.)^  ^If this variable
4808** is a NULL pointer, then SQLite performs a search for an appropriate
4809** temporary file directory.
4810**
4811** Applications are strongly discouraged from using this global variable.
4812** It is required to set a temporary folder on Windows Runtime (WinRT).
4813** But for all other platforms, it is highly recommended that applications
4814** neither read nor write this variable.  This global variable is a relic
4815** that exists for backwards compatibility of legacy applications and should
4816** be avoided in new projects.
4817**
4818** It is not safe to read or modify this variable in more than one
4819** thread at a time.  It is not safe to read or modify this variable
4820** if a [database connection] is being used at the same time in a separate
4821** thread.
4822** It is intended that this variable be set once
4823** as part of process initialization and before any SQLite interface
4824** routines have been called and that this variable remain unchanged
4825** thereafter.
4826**
4827** ^The [temp_store_directory pragma] may modify this variable and cause
4828** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
4829** the [temp_store_directory pragma] always assumes that any string
4830** that this variable points to is held in memory obtained from
4831** [sqlite3_malloc] and the pragma may attempt to free that memory
4832** using [sqlite3_free].
4833** Hence, if this variable is modified directly, either it should be
4834** made NULL or made to point to memory obtained from [sqlite3_malloc]
4835** or else the use of the [temp_store_directory pragma] should be avoided.
4836** Except when requested by the [temp_store_directory pragma], SQLite
4837** does not free the memory that sqlite3_temp_directory points to.  If
4838** the application wants that memory to be freed, it must do
4839** so itself, taking care to only do so after all [database connection]
4840** objects have been destroyed.
4841**
4842** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
4843** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
4844** features that require the use of temporary files may fail.  Here is an
4845** example of how to do this using C++ with the Windows Runtime:
4846**
4847** <blockquote><pre>
4848** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
4849** &nbsp;     TemporaryFolder->Path->Data();
4850** char zPathBuf&#91;MAX_PATH + 1&#93;;
4851** memset(zPathBuf, 0, sizeof(zPathBuf));
4852** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
4853** &nbsp;     NULL, NULL);
4854** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
4855** </pre></blockquote>
4856*/
4857SQLITE_API char *sqlite3_temp_directory;
4858
4859/*
4860** CAPI3REF: Name Of The Folder Holding Database Files
4861**
4862** ^(If this global variable is made to point to a string which is
4863** the name of a folder (a.k.a. directory), then all database files
4864** specified with a relative pathname and created or accessed by
4865** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
4866** to be relative to that directory.)^ ^If this variable is a NULL
4867** pointer, then SQLite assumes that all database files specified
4868** with a relative pathname are relative to the current directory
4869** for the process.  Only the windows VFS makes use of this global
4870** variable; it is ignored by the unix VFS.
4871**
4872** Changing the value of this variable while a database connection is
4873** open can result in a corrupt database.
4874**
4875** It is not safe to read or modify this variable in more than one
4876** thread at a time.  It is not safe to read or modify this variable
4877** if a [database connection] is being used at the same time in a separate
4878** thread.
4879** It is intended that this variable be set once
4880** as part of process initialization and before any SQLite interface
4881** routines have been called and that this variable remain unchanged
4882** thereafter.
4883**
4884** ^The [data_store_directory pragma] may modify this variable and cause
4885** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
4886** the [data_store_directory pragma] always assumes that any string
4887** that this variable points to is held in memory obtained from
4888** [sqlite3_malloc] and the pragma may attempt to free that memory
4889** using [sqlite3_free].
4890** Hence, if this variable is modified directly, either it should be
4891** made NULL or made to point to memory obtained from [sqlite3_malloc]
4892** or else the use of the [data_store_directory pragma] should be avoided.
4893*/
4894SQLITE_API char *sqlite3_data_directory;
4895
4896/*
4897** CAPI3REF: Test For Auto-Commit Mode
4898** KEYWORDS: {autocommit mode}
4899**
4900** ^The sqlite3_get_autocommit() interface returns non-zero or
4901** zero if the given database connection is or is not in autocommit mode,
4902** respectively.  ^Autocommit mode is on by default.
4903** ^Autocommit mode is disabled by a [BEGIN] statement.
4904** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
4905**
4906** If certain kinds of errors occur on a statement within a multi-statement
4907** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
4908** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
4909** transaction might be rolled back automatically.  The only way to
4910** find out whether SQLite automatically rolled back the transaction after
4911** an error is to use this function.
4912**
4913** If another thread changes the autocommit status of the database
4914** connection while this routine is running, then the return value
4915** is undefined.
4916*/
4917SQLITE_API int sqlite3_get_autocommit(sqlite3*);
4918
4919/*
4920** CAPI3REF: Find The Database Handle Of A Prepared Statement
4921**
4922** ^The sqlite3_db_handle interface returns the [database connection] handle
4923** to which a [prepared statement] belongs.  ^The [database connection]
4924** returned by sqlite3_db_handle is the same [database connection]
4925** that was the first argument
4926** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
4927** create the statement in the first place.
4928*/
4929SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
4930
4931/*
4932** CAPI3REF: Return The Filename For A Database Connection
4933**
4934** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
4935** associated with database N of connection D.  ^The main database file
4936** has the name "main".  If there is no attached database N on the database
4937** connection D, or if database N is a temporary or in-memory database, then
4938** a NULL pointer is returned.
4939**
4940** ^The filename returned by this function is the output of the
4941** xFullPathname method of the [VFS].  ^In other words, the filename
4942** will be an absolute pathname, even if the filename used
4943** to open the database originally was a URI or relative pathname.
4944*/
4945SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
4946
4947/*
4948** CAPI3REF: Determine if a database is read-only
4949**
4950** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
4951** of connection D is read-only, 0 if it is read/write, or -1 if N is not
4952** the name of a database on connection D.
4953*/
4954SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
4955
4956/*
4957** CAPI3REF: Find the next prepared statement
4958**
4959** ^This interface returns a pointer to the next [prepared statement] after
4960** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
4961** then this interface returns a pointer to the first prepared statement
4962** associated with the database connection pDb.  ^If no prepared statement
4963** satisfies the conditions of this routine, it returns NULL.
4964**
4965** The [database connection] pointer D in a call to
4966** [sqlite3_next_stmt(D,S)] must refer to an open database
4967** connection and in particular must not be a NULL pointer.
4968*/
4969SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
4970
4971/*
4972** CAPI3REF: Commit And Rollback Notification Callbacks
4973**
4974** ^The sqlite3_commit_hook() interface registers a callback
4975** function to be invoked whenever a transaction is [COMMIT | committed].
4976** ^Any callback set by a previous call to sqlite3_commit_hook()
4977** for the same database connection is overridden.
4978** ^The sqlite3_rollback_hook() interface registers a callback
4979** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
4980** ^Any callback set by a previous call to sqlite3_rollback_hook()
4981** for the same database connection is overridden.
4982** ^The pArg argument is passed through to the callback.
4983** ^If the callback on a commit hook function returns non-zero,
4984** then the commit is converted into a rollback.
4985**
4986** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
4987** return the P argument from the previous call of the same function
4988** on the same [database connection] D, or NULL for
4989** the first call for each function on D.
4990**
4991** The commit and rollback hook callbacks are not reentrant.
4992** The callback implementation must not do anything that will modify
4993** the database connection that invoked the callback.  Any actions
4994** to modify the database connection must be deferred until after the
4995** completion of the [sqlite3_step()] call that triggered the commit
4996** or rollback hook in the first place.
4997** Note that running any other SQL statements, including SELECT statements,
4998** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
4999** the database connections for the meaning of "modify" in this paragraph.
5000**
5001** ^Registering a NULL function disables the callback.
5002**
5003** ^When the commit hook callback routine returns zero, the [COMMIT]
5004** operation is allowed to continue normally.  ^If the commit hook
5005** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
5006** ^The rollback hook is invoked on a rollback that results from a commit
5007** hook returning non-zero, just as it would be with any other rollback.
5008**
5009** ^For the purposes of this API, a transaction is said to have been
5010** rolled back if an explicit "ROLLBACK" statement is executed, or
5011** an error or constraint causes an implicit rollback to occur.
5012** ^The rollback callback is not invoked if a transaction is
5013** automatically rolled back because the database connection is closed.
5014**
5015** See also the [sqlite3_update_hook()] interface.
5016*/
5017SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
5018SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
5019
5020/*
5021** CAPI3REF: Data Change Notification Callbacks
5022**
5023** ^The sqlite3_update_hook() interface registers a callback function
5024** with the [database connection] identified by the first argument
5025** to be invoked whenever a row is updated, inserted or deleted in
5026** a rowid table.
5027** ^Any callback set by a previous call to this function
5028** for the same database connection is overridden.
5029**
5030** ^The second argument is a pointer to the function to invoke when a
5031** row is updated, inserted or deleted in a rowid table.
5032** ^The first argument to the callback is a copy of the third argument
5033** to sqlite3_update_hook().
5034** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
5035** or [SQLITE_UPDATE], depending on the operation that caused the callback
5036** to be invoked.
5037** ^The third and fourth arguments to the callback contain pointers to the
5038** database and table name containing the affected row.
5039** ^The final callback parameter is the [rowid] of the row.
5040** ^In the case of an update, this is the [rowid] after the update takes place.
5041**
5042** ^(The update hook is not invoked when internal system tables are
5043** modified (i.e. sqlite_master and sqlite_sequence).)^
5044** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
5045**
5046** ^In the current implementation, the update hook
5047** is not invoked when duplication rows are deleted because of an
5048** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
5049** invoked when rows are deleted using the [truncate optimization].
5050** The exceptions defined in this paragraph might change in a future
5051** release of SQLite.
5052**
5053** The update hook implementation must not do anything that will modify
5054** the database connection that invoked the update hook.  Any actions
5055** to modify the database connection must be deferred until after the
5056** completion of the [sqlite3_step()] call that triggered the update hook.
5057** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
5058** database connections for the meaning of "modify" in this paragraph.
5059**
5060** ^The sqlite3_update_hook(D,C,P) function
5061** returns the P argument from the previous call
5062** on the same [database connection] D, or NULL for
5063** the first call on D.
5064**
5065** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
5066** interfaces.
5067*/
5068SQLITE_API void *sqlite3_update_hook(
5069  sqlite3*,
5070  void(*)(void *,int ,char const *,char const *,sqlite3_int64),
5071  void*
5072);
5073
5074/*
5075** CAPI3REF: Enable Or Disable Shared Pager Cache
5076**
5077** ^(This routine enables or disables the sharing of the database cache
5078** and schema data structures between [database connection | connections]
5079** to the same database. Sharing is enabled if the argument is true
5080** and disabled if the argument is false.)^
5081**
5082** ^Cache sharing is enabled and disabled for an entire process.
5083** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
5084** sharing was enabled or disabled for each thread separately.
5085**
5086** ^(The cache sharing mode set by this interface effects all subsequent
5087** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
5088** Existing database connections continue use the sharing mode
5089** that was in effect at the time they were opened.)^
5090**
5091** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
5092** successfully.  An [error code] is returned otherwise.)^
5093**
5094** ^Shared cache is disabled by default. But this might change in
5095** future releases of SQLite.  Applications that care about shared
5096** cache setting should set it explicitly.
5097**
5098** This interface is threadsafe on processors where writing a
5099** 32-bit integer is atomic.
5100**
5101** See Also:  [SQLite Shared-Cache Mode]
5102*/
5103SQLITE_API int sqlite3_enable_shared_cache(int);
5104
5105/*
5106** CAPI3REF: Attempt To Free Heap Memory
5107**
5108** ^The sqlite3_release_memory() interface attempts to free N bytes
5109** of heap memory by deallocating non-essential memory allocations
5110** held by the database library.   Memory used to cache database
5111** pages to improve performance is an example of non-essential memory.
5112** ^sqlite3_release_memory() returns the number of bytes actually freed,
5113** which might be more or less than the amount requested.
5114** ^The sqlite3_release_memory() routine is a no-op returning zero
5115** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5116**
5117** See also: [sqlite3_db_release_memory()]
5118*/
5119SQLITE_API int sqlite3_release_memory(int);
5120
5121/*
5122** CAPI3REF: Free Memory Used By A Database Connection
5123**
5124** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
5125** memory as possible from database connection D. Unlike the
5126** [sqlite3_release_memory()] interface, this interface is in effect even
5127** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
5128** omitted.
5129**
5130** See also: [sqlite3_release_memory()]
5131*/
5132SQLITE_API int sqlite3_db_release_memory(sqlite3*);
5133
5134/*
5135** CAPI3REF: Impose A Limit On Heap Size
5136**
5137** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
5138** soft limit on the amount of heap memory that may be allocated by SQLite.
5139** ^SQLite strives to keep heap memory utilization below the soft heap
5140** limit by reducing the number of pages held in the page cache
5141** as heap memory usages approaches the limit.
5142** ^The soft heap limit is "soft" because even though SQLite strives to stay
5143** below the limit, it will exceed the limit rather than generate
5144** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
5145** is advisory only.
5146**
5147** ^The return value from sqlite3_soft_heap_limit64() is the size of
5148** the soft heap limit prior to the call, or negative in the case of an
5149** error.  ^If the argument N is negative
5150** then no change is made to the soft heap limit.  Hence, the current
5151** size of the soft heap limit can be determined by invoking
5152** sqlite3_soft_heap_limit64() with a negative argument.
5153**
5154** ^If the argument N is zero then the soft heap limit is disabled.
5155**
5156** ^(The soft heap limit is not enforced in the current implementation
5157** if one or more of following conditions are true:
5158**
5159** <ul>
5160** <li> The soft heap limit is set to zero.
5161** <li> Memory accounting is disabled using a combination of the
5162**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
5163**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
5164** <li> An alternative page cache implementation is specified using
5165**      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
5166** <li> The page cache allocates from its own memory pool supplied
5167**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
5168**      from the heap.
5169** </ul>)^
5170**
5171** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
5172** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
5173** compile-time option is invoked.  With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
5174** the soft heap limit is enforced on every memory allocation.  Without
5175** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
5176** when memory is allocated by the page cache.  Testing suggests that because
5177** the page cache is the predominate memory user in SQLite, most
5178** applications will achieve adequate soft heap limit enforcement without
5179** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5180**
5181** The circumstances under which SQLite will enforce the soft heap limit may
5182** changes in future releases of SQLite.
5183*/
5184SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
5185
5186/*
5187** CAPI3REF: Deprecated Soft Heap Limit Interface
5188** DEPRECATED
5189**
5190** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
5191** interface.  This routine is provided for historical compatibility
5192** only.  All new applications should use the
5193** [sqlite3_soft_heap_limit64()] interface rather than this one.
5194*/
5195SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
5196
5197
5198/*
5199** CAPI3REF: Extract Metadata About A Column Of A Table
5200**
5201** ^This routine returns metadata about a specific column of a specific
5202** database table accessible using the [database connection] handle
5203** passed as the first function argument.
5204**
5205** ^The column is identified by the second, third and fourth parameters to
5206** this function. ^The second parameter is either the name of the database
5207** (i.e. "main", "temp", or an attached database) containing the specified
5208** table or NULL. ^If it is NULL, then all attached databases are searched
5209** for the table using the same algorithm used by the database engine to
5210** resolve unqualified table references.
5211**
5212** ^The third and fourth parameters to this function are the table and column
5213** name of the desired column, respectively. Neither of these parameters
5214** may be NULL.
5215**
5216** ^Metadata is returned by writing to the memory locations passed as the 5th
5217** and subsequent parameters to this function. ^Any of these arguments may be
5218** NULL, in which case the corresponding element of metadata is omitted.
5219**
5220** ^(<blockquote>
5221** <table border="1">
5222** <tr><th> Parameter <th> Output<br>Type <th>  Description
5223**
5224** <tr><td> 5th <td> const char* <td> Data type
5225** <tr><td> 6th <td> const char* <td> Name of default collation sequence
5226** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
5227** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
5228** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
5229** </table>
5230** </blockquote>)^
5231**
5232** ^The memory pointed to by the character pointers returned for the
5233** declaration type and collation sequence is valid only until the next
5234** call to any SQLite API function.
5235**
5236** ^If the specified table is actually a view, an [error code] is returned.
5237**
5238** ^If the specified column is "rowid", "oid" or "_rowid_" and an
5239** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
5240** parameters are set for the explicitly declared column. ^(If there is no
5241** explicitly declared [INTEGER PRIMARY KEY] column, then the output
5242** parameters are set as follows:
5243**
5244** <pre>
5245**     data type: "INTEGER"
5246**     collation sequence: "BINARY"
5247**     not null: 0
5248**     primary key: 1
5249**     auto increment: 0
5250** </pre>)^
5251**
5252** ^(This function may load one or more schemas from database files. If an
5253** error occurs during this process, or if the requested table or column
5254** cannot be found, an [error code] is returned and an error message left
5255** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
5256**
5257** ^This API is only available if the library was compiled with the
5258** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
5259*/
5260SQLITE_API int sqlite3_table_column_metadata(
5261  sqlite3 *db,                /* Connection handle */
5262  const char *zDbName,        /* Database name or NULL */
5263  const char *zTableName,     /* Table name */
5264  const char *zColumnName,    /* Column name */
5265  char const **pzDataType,    /* OUTPUT: Declared data type */
5266  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
5267  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
5268  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
5269  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
5270);
5271
5272/*
5273** CAPI3REF: Load An Extension
5274**
5275** ^This interface loads an SQLite extension library from the named file.
5276**
5277** ^The sqlite3_load_extension() interface attempts to load an
5278** [SQLite extension] library contained in the file zFile.  If
5279** the file cannot be loaded directly, attempts are made to load
5280** with various operating-system specific extensions added.
5281** So for example, if "samplelib" cannot be loaded, then names like
5282** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
5283** be tried also.
5284**
5285** ^The entry point is zProc.
5286** ^(zProc may be 0, in which case SQLite will try to come up with an
5287** entry point name on its own.  It first tries "sqlite3_extension_init".
5288** If that does not work, it constructs a name "sqlite3_X_init" where the
5289** X is consists of the lower-case equivalent of all ASCII alphabetic
5290** characters in the filename from the last "/" to the first following
5291** "." and omitting any initial "lib".)^
5292** ^The sqlite3_load_extension() interface returns
5293** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
5294** ^If an error occurs and pzErrMsg is not 0, then the
5295** [sqlite3_load_extension()] interface shall attempt to
5296** fill *pzErrMsg with error message text stored in memory
5297** obtained from [sqlite3_malloc()]. The calling function
5298** should free this memory by calling [sqlite3_free()].
5299**
5300** ^Extension loading must be enabled using
5301** [sqlite3_enable_load_extension()] prior to calling this API,
5302** otherwise an error will be returned.
5303**
5304** See also the [load_extension() SQL function].
5305*/
5306SQLITE_API int sqlite3_load_extension(
5307  sqlite3 *db,          /* Load the extension into this database connection */
5308  const char *zFile,    /* Name of the shared library containing extension */
5309  const char *zProc,    /* Entry point.  Derived from zFile if 0 */
5310  char **pzErrMsg       /* Put error message here if not 0 */
5311);
5312
5313/*
5314** CAPI3REF: Enable Or Disable Extension Loading
5315**
5316** ^So as not to open security holes in older applications that are
5317** unprepared to deal with [extension loading], and as a means of disabling
5318** [extension loading] while evaluating user-entered SQL, the following API
5319** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5320**
5321** ^Extension loading is off by default.
5322** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5323** to turn extension loading on and call it with onoff==0 to turn
5324** it back off again.
5325*/
5326SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
5327
5328/*
5329** CAPI3REF: Automatically Load Statically Linked Extensions
5330**
5331** ^This interface causes the xEntryPoint() function to be invoked for
5332** each new [database connection] that is created.  The idea here is that
5333** xEntryPoint() is the entry point for a statically linked [SQLite extension]
5334** that is to be automatically loaded into all new database connections.
5335**
5336** ^(Even though the function prototype shows that xEntryPoint() takes
5337** no arguments and returns void, SQLite invokes xEntryPoint() with three
5338** arguments and expects and integer result as if the signature of the
5339** entry point where as follows:
5340**
5341** <blockquote><pre>
5342** &nbsp;  int xEntryPoint(
5343** &nbsp;    sqlite3 *db,
5344** &nbsp;    const char **pzErrMsg,
5345** &nbsp;    const struct sqlite3_api_routines *pThunk
5346** &nbsp;  );
5347** </pre></blockquote>)^
5348**
5349** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
5350** point to an appropriate error message (obtained from [sqlite3_mprintf()])
5351** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
5352** is NULL before calling the xEntryPoint().  ^SQLite will invoke
5353** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
5354** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
5355** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
5356**
5357** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
5358** on the list of automatic extensions is a harmless no-op. ^No entry point
5359** will be called more than once for each database connection that is opened.
5360**
5361** See also: [sqlite3_reset_auto_extension()]
5362** and [sqlite3_cancel_auto_extension()]
5363*/
5364SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void));
5365
5366/*
5367** CAPI3REF: Cancel Automatic Extension Loading
5368**
5369** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
5370** initialization routine X that was registered using a prior call to
5371** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
5372** routine returns 1 if initialization routine X was successfully
5373** unregistered and it returns 0 if X was not on the list of initialization
5374** routines.
5375*/
5376SQLITE_API int sqlite3_cancel_auto_extension(void (*xEntryPoint)(void));
5377
5378/*
5379** CAPI3REF: Reset Automatic Extension Loading
5380**
5381** ^This interface disables all automatic extensions previously
5382** registered using [sqlite3_auto_extension()].
5383*/
5384SQLITE_API void sqlite3_reset_auto_extension(void);
5385
5386/*
5387** The interface to the virtual-table mechanism is currently considered
5388** to be experimental.  The interface might change in incompatible ways.
5389** If this is a problem for you, do not use the interface at this time.
5390**
5391** When the virtual-table mechanism stabilizes, we will declare the
5392** interface fixed, support it indefinitely, and remove this comment.
5393*/
5394
5395/*
5396** Structures used by the virtual table interface
5397*/
5398typedef struct sqlite3_vtab sqlite3_vtab;
5399typedef struct sqlite3_index_info sqlite3_index_info;
5400typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
5401typedef struct sqlite3_module sqlite3_module;
5402
5403/*
5404** CAPI3REF: Virtual Table Object
5405** KEYWORDS: sqlite3_module {virtual table module}
5406**
5407** This structure, sometimes called a "virtual table module",
5408** defines the implementation of a [virtual tables].
5409** This structure consists mostly of methods for the module.
5410**
5411** ^A virtual table module is created by filling in a persistent
5412** instance of this structure and passing a pointer to that instance
5413** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
5414** ^The registration remains valid until it is replaced by a different
5415** module or until the [database connection] closes.  The content
5416** of this structure must not change while it is registered with
5417** any database connection.
5418*/
5419struct sqlite3_module {
5420  int iVersion;
5421  int (*xCreate)(sqlite3*, void *pAux,
5422               int argc, const char *const*argv,
5423               sqlite3_vtab **ppVTab, char**);
5424  int (*xConnect)(sqlite3*, void *pAux,
5425               int argc, const char *const*argv,
5426               sqlite3_vtab **ppVTab, char**);
5427  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
5428  int (*xDisconnect)(sqlite3_vtab *pVTab);
5429  int (*xDestroy)(sqlite3_vtab *pVTab);
5430  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
5431  int (*xClose)(sqlite3_vtab_cursor*);
5432  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
5433                int argc, sqlite3_value **argv);
5434  int (*xNext)(sqlite3_vtab_cursor*);
5435  int (*xEof)(sqlite3_vtab_cursor*);
5436  int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
5437  int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
5438  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
5439  int (*xBegin)(sqlite3_vtab *pVTab);
5440  int (*xSync)(sqlite3_vtab *pVTab);
5441  int (*xCommit)(sqlite3_vtab *pVTab);
5442  int (*xRollback)(sqlite3_vtab *pVTab);
5443  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
5444                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
5445                       void **ppArg);
5446  int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
5447  /* The methods above are in version 1 of the sqlite_module object. Those
5448  ** below are for version 2 and greater. */
5449  int (*xSavepoint)(sqlite3_vtab *pVTab, int);
5450  int (*xRelease)(sqlite3_vtab *pVTab, int);
5451  int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
5452};
5453
5454/*
5455** CAPI3REF: Virtual Table Indexing Information
5456** KEYWORDS: sqlite3_index_info
5457**
5458** The sqlite3_index_info structure and its substructures is used as part
5459** of the [virtual table] interface to
5460** pass information into and receive the reply from the [xBestIndex]
5461** method of a [virtual table module].  The fields under **Inputs** are the
5462** inputs to xBestIndex and are read-only.  xBestIndex inserts its
5463** results into the **Outputs** fields.
5464**
5465** ^(The aConstraint[] array records WHERE clause constraints of the form:
5466**
5467** <blockquote>column OP expr</blockquote>
5468**
5469** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
5470** stored in aConstraint[].op using one of the
5471** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
5472** ^(The index of the column is stored in
5473** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
5474** expr on the right-hand side can be evaluated (and thus the constraint
5475** is usable) and false if it cannot.)^
5476**
5477** ^The optimizer automatically inverts terms of the form "expr OP column"
5478** and makes other simplifications to the WHERE clause in an attempt to
5479** get as many WHERE clause terms into the form shown above as possible.
5480** ^The aConstraint[] array only reports WHERE clause terms that are
5481** relevant to the particular virtual table being queried.
5482**
5483** ^Information about the ORDER BY clause is stored in aOrderBy[].
5484** ^Each term of aOrderBy records a column of the ORDER BY clause.
5485**
5486** The [xBestIndex] method must fill aConstraintUsage[] with information
5487** about what parameters to pass to xFilter.  ^If argvIndex>0 then
5488** the right-hand side of the corresponding aConstraint[] is evaluated
5489** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
5490** is true, then the constraint is assumed to be fully handled by the
5491** virtual table and is not checked again by SQLite.)^
5492**
5493** ^The idxNum and idxPtr values are recorded and passed into the
5494** [xFilter] method.
5495** ^[sqlite3_free()] is used to free idxPtr if and only if
5496** needToFreeIdxPtr is true.
5497**
5498** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
5499** the correct order to satisfy the ORDER BY clause so that no separate
5500** sorting step is required.
5501**
5502** ^The estimatedCost value is an estimate of the cost of a particular
5503** strategy. A cost of N indicates that the cost of the strategy is similar
5504** to a linear scan of an SQLite table with N rows. A cost of log(N)
5505** indicates that the expense of the operation is similar to that of a
5506** binary search on a unique indexed field of an SQLite table with N rows.
5507**
5508** ^The estimatedRows value is an estimate of the number of rows that
5509** will be returned by the strategy.
5510**
5511** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
5512** structure for SQLite version 3.8.2. If a virtual table extension is
5513** used with an SQLite version earlier than 3.8.2, the results of attempting
5514** to read or write the estimatedRows field are undefined (but are likely
5515** to included crashing the application). The estimatedRows field should
5516** therefore only be used if [sqlite3_libversion_number()] returns a
5517** value greater than or equal to 3008002.
5518*/
5519struct sqlite3_index_info {
5520  /* Inputs */
5521  int nConstraint;           /* Number of entries in aConstraint */
5522  struct sqlite3_index_constraint {
5523     int iColumn;              /* Column on left-hand side of constraint */
5524     unsigned char op;         /* Constraint operator */
5525     unsigned char usable;     /* True if this constraint is usable */
5526     int iTermOffset;          /* Used internally - xBestIndex should ignore */
5527  } *aConstraint;            /* Table of WHERE clause constraints */
5528  int nOrderBy;              /* Number of terms in the ORDER BY clause */
5529  struct sqlite3_index_orderby {
5530     int iColumn;              /* Column number */
5531     unsigned char desc;       /* True for DESC.  False for ASC. */
5532  } *aOrderBy;               /* The ORDER BY clause */
5533  /* Outputs */
5534  struct sqlite3_index_constraint_usage {
5535    int argvIndex;           /* if >0, constraint is part of argv to xFilter */
5536    unsigned char omit;      /* Do not code a test for this constraint */
5537  } *aConstraintUsage;
5538  int idxNum;                /* Number used to identify the index */
5539  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
5540  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
5541  int orderByConsumed;       /* True if output is already ordered */
5542  double estimatedCost;           /* Estimated cost of using this index */
5543  /* Fields below are only available in SQLite 3.8.2 and later */
5544  sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
5545};
5546
5547/*
5548** CAPI3REF: Virtual Table Constraint Operator Codes
5549**
5550** These macros defined the allowed values for the
5551** [sqlite3_index_info].aConstraint[].op field.  Each value represents
5552** an operator that is part of a constraint term in the wHERE clause of
5553** a query that uses a [virtual table].
5554*/
5555#define SQLITE_INDEX_CONSTRAINT_EQ    2
5556#define SQLITE_INDEX_CONSTRAINT_GT    4
5557#define SQLITE_INDEX_CONSTRAINT_LE    8
5558#define SQLITE_INDEX_CONSTRAINT_LT    16
5559#define SQLITE_INDEX_CONSTRAINT_GE    32
5560#define SQLITE_INDEX_CONSTRAINT_MATCH 64
5561
5562/*
5563** CAPI3REF: Register A Virtual Table Implementation
5564**
5565** ^These routines are used to register a new [virtual table module] name.
5566** ^Module names must be registered before
5567** creating a new [virtual table] using the module and before using a
5568** preexisting [virtual table] for the module.
5569**
5570** ^The module name is registered on the [database connection] specified
5571** by the first parameter.  ^The name of the module is given by the
5572** second parameter.  ^The third parameter is a pointer to
5573** the implementation of the [virtual table module].   ^The fourth
5574** parameter is an arbitrary client data pointer that is passed through
5575** into the [xCreate] and [xConnect] methods of the virtual table module
5576** when a new virtual table is be being created or reinitialized.
5577**
5578** ^The sqlite3_create_module_v2() interface has a fifth parameter which
5579** is a pointer to a destructor for the pClientData.  ^SQLite will
5580** invoke the destructor function (if it is not NULL) when SQLite
5581** no longer needs the pClientData pointer.  ^The destructor will also
5582** be invoked if the call to sqlite3_create_module_v2() fails.
5583** ^The sqlite3_create_module()
5584** interface is equivalent to sqlite3_create_module_v2() with a NULL
5585** destructor.
5586*/
5587SQLITE_API int sqlite3_create_module(
5588  sqlite3 *db,               /* SQLite connection to register module with */
5589  const char *zName,         /* Name of the module */
5590  const sqlite3_module *p,   /* Methods for the module */
5591  void *pClientData          /* Client data for xCreate/xConnect */
5592);
5593SQLITE_API int sqlite3_create_module_v2(
5594  sqlite3 *db,               /* SQLite connection to register module with */
5595  const char *zName,         /* Name of the module */
5596  const sqlite3_module *p,   /* Methods for the module */
5597  void *pClientData,         /* Client data for xCreate/xConnect */
5598  void(*xDestroy)(void*)     /* Module destructor function */
5599);
5600
5601/*
5602** CAPI3REF: Virtual Table Instance Object
5603** KEYWORDS: sqlite3_vtab
5604**
5605** Every [virtual table module] implementation uses a subclass
5606** of this object to describe a particular instance
5607** of the [virtual table].  Each subclass will
5608** be tailored to the specific needs of the module implementation.
5609** The purpose of this superclass is to define certain fields that are
5610** common to all module implementations.
5611**
5612** ^Virtual tables methods can set an error message by assigning a
5613** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
5614** take care that any prior string is freed by a call to [sqlite3_free()]
5615** prior to assigning a new string to zErrMsg.  ^After the error message
5616** is delivered up to the client application, the string will be automatically
5617** freed by sqlite3_free() and the zErrMsg field will be zeroed.
5618*/
5619struct sqlite3_vtab {
5620  const sqlite3_module *pModule;  /* The module for this virtual table */
5621  int nRef;                       /* NO LONGER USED */
5622  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
5623  /* Virtual table implementations will typically add additional fields */
5624};
5625
5626/*
5627** CAPI3REF: Virtual Table Cursor Object
5628** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
5629**
5630** Every [virtual table module] implementation uses a subclass of the
5631** following structure to describe cursors that point into the
5632** [virtual table] and are used
5633** to loop through the virtual table.  Cursors are created using the
5634** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
5635** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
5636** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
5637** of the module.  Each module implementation will define
5638** the content of a cursor structure to suit its own needs.
5639**
5640** This superclass exists in order to define fields of the cursor that
5641** are common to all implementations.
5642*/
5643struct sqlite3_vtab_cursor {
5644  sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
5645  /* Virtual table implementations will typically add additional fields */
5646};
5647
5648/*
5649** CAPI3REF: Declare The Schema Of A Virtual Table
5650**
5651** ^The [xCreate] and [xConnect] methods of a
5652** [virtual table module] call this interface
5653** to declare the format (the names and datatypes of the columns) of
5654** the virtual tables they implement.
5655*/
5656SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
5657
5658/*
5659** CAPI3REF: Overload A Function For A Virtual Table
5660**
5661** ^(Virtual tables can provide alternative implementations of functions
5662** using the [xFindFunction] method of the [virtual table module].
5663** But global versions of those functions
5664** must exist in order to be overloaded.)^
5665**
5666** ^(This API makes sure a global version of a function with a particular
5667** name and number of parameters exists.  If no such function exists
5668** before this API is called, a new function is created.)^  ^The implementation
5669** of the new function always causes an exception to be thrown.  So
5670** the new function is not good for anything by itself.  Its only
5671** purpose is to be a placeholder function that can be overloaded
5672** by a [virtual table].
5673*/
5674SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
5675
5676/*
5677** The interface to the virtual-table mechanism defined above (back up
5678** to a comment remarkably similar to this one) is currently considered
5679** to be experimental.  The interface might change in incompatible ways.
5680** If this is a problem for you, do not use the interface at this time.
5681**
5682** When the virtual-table mechanism stabilizes, we will declare the
5683** interface fixed, support it indefinitely, and remove this comment.
5684*/
5685
5686/*
5687** CAPI3REF: A Handle To An Open BLOB
5688** KEYWORDS: {BLOB handle} {BLOB handles}
5689**
5690** An instance of this object represents an open BLOB on which
5691** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
5692** ^Objects of this type are created by [sqlite3_blob_open()]
5693** and destroyed by [sqlite3_blob_close()].
5694** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
5695** can be used to read or write small subsections of the BLOB.
5696** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
5697*/
5698typedef struct sqlite3_blob sqlite3_blob;
5699
5700/*
5701** CAPI3REF: Open A BLOB For Incremental I/O
5702**
5703** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
5704** in row iRow, column zColumn, table zTable in database zDb;
5705** in other words, the same BLOB that would be selected by:
5706**
5707** <pre>
5708**     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
5709** </pre>)^
5710**
5711** ^If the flags parameter is non-zero, then the BLOB is opened for read
5712** and write access. ^If it is zero, the BLOB is opened for read access.
5713** ^It is not possible to open a column that is part of an index or primary
5714** key for writing. ^If [foreign key constraints] are enabled, it is
5715** not possible to open a column that is part of a [child key] for writing.
5716**
5717** ^Note that the database name is not the filename that contains
5718** the database but rather the symbolic name of the database that
5719** appears after the AS keyword when the database is connected using [ATTACH].
5720** ^For the main database file, the database name is "main".
5721** ^For TEMP tables, the database name is "temp".
5722**
5723** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
5724** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
5725** to be a null pointer.)^
5726** ^This function sets the [database connection] error code and message
5727** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
5728** functions. ^Note that the *ppBlob variable is always initialized in a
5729** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
5730** regardless of the success or failure of this routine.
5731**
5732** ^(If the row that a BLOB handle points to is modified by an
5733** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
5734** then the BLOB handle is marked as "expired".
5735** This is true if any column of the row is changed, even a column
5736** other than the one the BLOB handle is open on.)^
5737** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
5738** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
5739** ^(Changes written into a BLOB prior to the BLOB expiring are not
5740** rolled back by the expiration of the BLOB.  Such changes will eventually
5741** commit if the transaction continues to completion.)^
5742**
5743** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
5744** the opened blob.  ^The size of a blob may not be changed by this
5745** interface.  Use the [UPDATE] SQL command to change the size of a
5746** blob.
5747**
5748** ^The [sqlite3_blob_open()] interface will fail for a [WITHOUT ROWID]
5749** table.  Incremental BLOB I/O is not possible on [WITHOUT ROWID] tables.
5750**
5751** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
5752** and the built-in [zeroblob] SQL function can be used, if desired,
5753** to create an empty, zero-filled blob in which to read or write using
5754** this interface.
5755**
5756** To avoid a resource leak, every open [BLOB handle] should eventually
5757** be released by a call to [sqlite3_blob_close()].
5758*/
5759SQLITE_API int sqlite3_blob_open(
5760  sqlite3*,
5761  const char *zDb,
5762  const char *zTable,
5763  const char *zColumn,
5764  sqlite3_int64 iRow,
5765  int flags,
5766  sqlite3_blob **ppBlob
5767);
5768
5769/*
5770** CAPI3REF: Move a BLOB Handle to a New Row
5771**
5772** ^This function is used to move an existing blob handle so that it points
5773** to a different row of the same database table. ^The new row is identified
5774** by the rowid value passed as the second argument. Only the row can be
5775** changed. ^The database, table and column on which the blob handle is open
5776** remain the same. Moving an existing blob handle to a new row can be
5777** faster than closing the existing handle and opening a new one.
5778**
5779** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
5780** it must exist and there must be either a blob or text value stored in
5781** the nominated column.)^ ^If the new row is not present in the table, or if
5782** it does not contain a blob or text value, or if another error occurs, an
5783** SQLite error code is returned and the blob handle is considered aborted.
5784** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
5785** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
5786** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
5787** always returns zero.
5788**
5789** ^This function sets the database handle error code and message.
5790*/
5791SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
5792
5793/*
5794** CAPI3REF: Close A BLOB Handle
5795**
5796** ^Closes an open [BLOB handle].
5797**
5798** ^Closing a BLOB shall cause the current transaction to commit
5799** if there are no other BLOBs, no pending prepared statements, and the
5800** database connection is in [autocommit mode].
5801** ^If any writes were made to the BLOB, they might be held in cache
5802** until the close operation if they will fit.
5803**
5804** ^(Closing the BLOB often forces the changes
5805** out to disk and so if any I/O errors occur, they will likely occur
5806** at the time when the BLOB is closed.  Any errors that occur during
5807** closing are reported as a non-zero return value.)^
5808**
5809** ^(The BLOB is closed unconditionally.  Even if this routine returns
5810** an error code, the BLOB is still closed.)^
5811**
5812** ^Calling this routine with a null pointer (such as would be returned
5813** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
5814*/
5815SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
5816
5817/*
5818** CAPI3REF: Return The Size Of An Open BLOB
5819**
5820** ^Returns the size in bytes of the BLOB accessible via the
5821** successfully opened [BLOB handle] in its only argument.  ^The
5822** incremental blob I/O routines can only read or overwriting existing
5823** blob content; they cannot change the size of a blob.
5824**
5825** This routine only works on a [BLOB handle] which has been created
5826** by a prior successful call to [sqlite3_blob_open()] and which has not
5827** been closed by [sqlite3_blob_close()].  Passing any other pointer in
5828** to this routine results in undefined and probably undesirable behavior.
5829*/
5830SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
5831
5832/*
5833** CAPI3REF: Read Data From A BLOB Incrementally
5834**
5835** ^(This function is used to read data from an open [BLOB handle] into a
5836** caller-supplied buffer. N bytes of data are copied into buffer Z
5837** from the open BLOB, starting at offset iOffset.)^
5838**
5839** ^If offset iOffset is less than N bytes from the end of the BLOB,
5840** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
5841** less than zero, [SQLITE_ERROR] is returned and no data is read.
5842** ^The size of the blob (and hence the maximum value of N+iOffset)
5843** can be determined using the [sqlite3_blob_bytes()] interface.
5844**
5845** ^An attempt to read from an expired [BLOB handle] fails with an
5846** error code of [SQLITE_ABORT].
5847**
5848** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
5849** Otherwise, an [error code] or an [extended error code] is returned.)^
5850**
5851** This routine only works on a [BLOB handle] which has been created
5852** by a prior successful call to [sqlite3_blob_open()] and which has not
5853** been closed by [sqlite3_blob_close()].  Passing any other pointer in
5854** to this routine results in undefined and probably undesirable behavior.
5855**
5856** See also: [sqlite3_blob_write()].
5857*/
5858SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
5859
5860/*
5861** CAPI3REF: Write Data Into A BLOB Incrementally
5862**
5863** ^This function is used to write data into an open [BLOB handle] from a
5864** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
5865** into the open BLOB, starting at offset iOffset.
5866**
5867** ^If the [BLOB handle] passed as the first argument was not opened for
5868** writing (the flags parameter to [sqlite3_blob_open()] was zero),
5869** this function returns [SQLITE_READONLY].
5870**
5871** ^This function may only modify the contents of the BLOB; it is
5872** not possible to increase the size of a BLOB using this API.
5873** ^If offset iOffset is less than N bytes from the end of the BLOB,
5874** [SQLITE_ERROR] is returned and no data is written.  ^If N is
5875** less than zero [SQLITE_ERROR] is returned and no data is written.
5876** The size of the BLOB (and hence the maximum value of N+iOffset)
5877** can be determined using the [sqlite3_blob_bytes()] interface.
5878**
5879** ^An attempt to write to an expired [BLOB handle] fails with an
5880** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
5881** before the [BLOB handle] expired are not rolled back by the
5882** expiration of the handle, though of course those changes might
5883** have been overwritten by the statement that expired the BLOB handle
5884** or by other independent statements.
5885**
5886** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
5887** Otherwise, an  [error code] or an [extended error code] is returned.)^
5888**
5889** This routine only works on a [BLOB handle] which has been created
5890** by a prior successful call to [sqlite3_blob_open()] and which has not
5891** been closed by [sqlite3_blob_close()].  Passing any other pointer in
5892** to this routine results in undefined and probably undesirable behavior.
5893**
5894** See also: [sqlite3_blob_read()].
5895*/
5896SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
5897
5898/*
5899** CAPI3REF: Virtual File System Objects
5900**
5901** A virtual filesystem (VFS) is an [sqlite3_vfs] object
5902** that SQLite uses to interact
5903** with the underlying operating system.  Most SQLite builds come with a
5904** single default VFS that is appropriate for the host computer.
5905** New VFSes can be registered and existing VFSes can be unregistered.
5906** The following interfaces are provided.
5907**
5908** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
5909** ^Names are case sensitive.
5910** ^Names are zero-terminated UTF-8 strings.
5911** ^If there is no match, a NULL pointer is returned.
5912** ^If zVfsName is NULL then the default VFS is returned.
5913**
5914** ^New VFSes are registered with sqlite3_vfs_register().
5915** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
5916** ^The same VFS can be registered multiple times without injury.
5917** ^To make an existing VFS into the default VFS, register it again
5918** with the makeDflt flag set.  If two different VFSes with the
5919** same name are registered, the behavior is undefined.  If a
5920** VFS is registered with a name that is NULL or an empty string,
5921** then the behavior is undefined.
5922**
5923** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
5924** ^(If the default VFS is unregistered, another VFS is chosen as
5925** the default.  The choice for the new VFS is arbitrary.)^
5926*/
5927SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
5928SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
5929SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
5930
5931/*
5932** CAPI3REF: Mutexes
5933**
5934** The SQLite core uses these routines for thread
5935** synchronization. Though they are intended for internal
5936** use by SQLite, code that links against SQLite is
5937** permitted to use any of these routines.
5938**
5939** The SQLite source code contains multiple implementations
5940** of these mutex routines.  An appropriate implementation
5941** is selected automatically at compile-time.  ^(The following
5942** implementations are available in the SQLite core:
5943**
5944** <ul>
5945** <li>   SQLITE_MUTEX_PTHREADS
5946** <li>   SQLITE_MUTEX_W32
5947** <li>   SQLITE_MUTEX_NOOP
5948** </ul>)^
5949**
5950** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
5951** that does no real locking and is appropriate for use in
5952** a single-threaded application.  ^The SQLITE_MUTEX_PTHREADS and
5953** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
5954** and Windows.
5955**
5956** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
5957** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
5958** implementation is included with the library. In this case the
5959** application must supply a custom mutex implementation using the
5960** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
5961** before calling sqlite3_initialize() or any other public sqlite3_
5962** function that calls sqlite3_initialize().)^
5963**
5964** ^The sqlite3_mutex_alloc() routine allocates a new
5965** mutex and returns a pointer to it. ^If it returns NULL
5966** that means that a mutex could not be allocated.  ^SQLite
5967** will unwind its stack and return an error.  ^(The argument
5968** to sqlite3_mutex_alloc() is one of these integer constants:
5969**
5970** <ul>
5971** <li>  SQLITE_MUTEX_FAST
5972** <li>  SQLITE_MUTEX_RECURSIVE
5973** <li>  SQLITE_MUTEX_STATIC_MASTER
5974** <li>  SQLITE_MUTEX_STATIC_MEM
5975** <li>  SQLITE_MUTEX_STATIC_OPEN
5976** <li>  SQLITE_MUTEX_STATIC_PRNG
5977** <li>  SQLITE_MUTEX_STATIC_LRU
5978** <li>  SQLITE_MUTEX_STATIC_PMEM
5979** <li>  SQLITE_MUTEX_STATIC_APP1
5980** <li>  SQLITE_MUTEX_STATIC_APP2
5981** </ul>)^
5982**
5983** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
5984** cause sqlite3_mutex_alloc() to create
5985** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
5986** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
5987** The mutex implementation does not need to make a distinction
5988** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
5989** not want to.  ^SQLite will only request a recursive mutex in
5990** cases where it really needs one.  ^If a faster non-recursive mutex
5991** implementation is available on the host platform, the mutex subsystem
5992** might return such a mutex in response to SQLITE_MUTEX_FAST.
5993**
5994** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
5995** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
5996** a pointer to a static preexisting mutex.  ^Six static mutexes are
5997** used by the current version of SQLite.  Future versions of SQLite
5998** may add additional static mutexes.  Static mutexes are for internal
5999** use by SQLite only.  Applications that use SQLite mutexes should
6000** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
6001** SQLITE_MUTEX_RECURSIVE.
6002**
6003** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
6004** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
6005** returns a different mutex on every call.  ^But for the static
6006** mutex types, the same mutex is returned on every call that has
6007** the same type number.
6008**
6009** ^The sqlite3_mutex_free() routine deallocates a previously
6010** allocated dynamic mutex.  ^SQLite is careful to deallocate every
6011** dynamic mutex that it allocates.  The dynamic mutexes must not be in
6012** use when they are deallocated.  Attempting to deallocate a static
6013** mutex results in undefined behavior.  ^SQLite never deallocates
6014** a static mutex.
6015**
6016** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
6017** to enter a mutex.  ^If another thread is already within the mutex,
6018** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
6019** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
6020** upon successful entry.  ^(Mutexes created using
6021** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
6022** In such cases the,
6023** mutex must be exited an equal number of times before another thread
6024** can enter.)^  ^(If the same thread tries to enter any other
6025** kind of mutex more than once, the behavior is undefined.
6026** SQLite will never exhibit
6027** such behavior in its own use of mutexes.)^
6028**
6029** ^(Some systems (for example, Windows 95) do not support the operation
6030** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
6031** will always return SQLITE_BUSY.  The SQLite core only ever uses
6032** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
6033**
6034** ^The sqlite3_mutex_leave() routine exits a mutex that was
6035** previously entered by the same thread.   ^(The behavior
6036** is undefined if the mutex is not currently entered by the
6037** calling thread or is not currently allocated.  SQLite will
6038** never do either.)^
6039**
6040** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
6041** sqlite3_mutex_leave() is a NULL pointer, then all three routines
6042** behave as no-ops.
6043**
6044** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
6045*/
6046SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
6047SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
6048SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
6049SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
6050SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
6051
6052/*
6053** CAPI3REF: Mutex Methods Object
6054**
6055** An instance of this structure defines the low-level routines
6056** used to allocate and use mutexes.
6057**
6058** Usually, the default mutex implementations provided by SQLite are
6059** sufficient, however the user has the option of substituting a custom
6060** implementation for specialized deployments or systems for which SQLite
6061** does not provide a suitable implementation. In this case, the user
6062** creates and populates an instance of this structure to pass
6063** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
6064** Additionally, an instance of this structure can be used as an
6065** output variable when querying the system for the current mutex
6066** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
6067**
6068** ^The xMutexInit method defined by this structure is invoked as
6069** part of system initialization by the sqlite3_initialize() function.
6070** ^The xMutexInit routine is called by SQLite exactly once for each
6071** effective call to [sqlite3_initialize()].
6072**
6073** ^The xMutexEnd method defined by this structure is invoked as
6074** part of system shutdown by the sqlite3_shutdown() function. The
6075** implementation of this method is expected to release all outstanding
6076** resources obtained by the mutex methods implementation, especially
6077** those obtained by the xMutexInit method.  ^The xMutexEnd()
6078** interface is invoked exactly once for each call to [sqlite3_shutdown()].
6079**
6080** ^(The remaining seven methods defined by this structure (xMutexAlloc,
6081** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
6082** xMutexNotheld) implement the following interfaces (respectively):
6083**
6084** <ul>
6085**   <li>  [sqlite3_mutex_alloc()] </li>
6086**   <li>  [sqlite3_mutex_free()] </li>
6087**   <li>  [sqlite3_mutex_enter()] </li>
6088**   <li>  [sqlite3_mutex_try()] </li>
6089**   <li>  [sqlite3_mutex_leave()] </li>
6090**   <li>  [sqlite3_mutex_held()] </li>
6091**   <li>  [sqlite3_mutex_notheld()] </li>
6092** </ul>)^
6093**
6094** The only difference is that the public sqlite3_XXX functions enumerated
6095** above silently ignore any invocations that pass a NULL pointer instead
6096** of a valid mutex handle. The implementations of the methods defined
6097** by this structure are not required to handle this case, the results
6098** of passing a NULL pointer instead of a valid mutex handle are undefined
6099** (i.e. it is acceptable to provide an implementation that segfaults if
6100** it is passed a NULL pointer).
6101**
6102** The xMutexInit() method must be threadsafe.  ^It must be harmless to
6103** invoke xMutexInit() multiple times within the same process and without
6104** intervening calls to xMutexEnd().  Second and subsequent calls to
6105** xMutexInit() must be no-ops.
6106**
6107** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
6108** and its associates).  ^Similarly, xMutexAlloc() must not use SQLite memory
6109** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
6110** memory allocation for a fast or recursive mutex.
6111**
6112** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
6113** called, but only if the prior call to xMutexInit returned SQLITE_OK.
6114** If xMutexInit fails in any way, it is expected to clean up after itself
6115** prior to returning.
6116*/
6117typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
6118struct sqlite3_mutex_methods {
6119  int (*xMutexInit)(void);
6120  int (*xMutexEnd)(void);
6121  sqlite3_mutex *(*xMutexAlloc)(int);
6122  void (*xMutexFree)(sqlite3_mutex *);
6123  void (*xMutexEnter)(sqlite3_mutex *);
6124  int (*xMutexTry)(sqlite3_mutex *);
6125  void (*xMutexLeave)(sqlite3_mutex *);
6126  int (*xMutexHeld)(sqlite3_mutex *);
6127  int (*xMutexNotheld)(sqlite3_mutex *);
6128};
6129
6130/*
6131** CAPI3REF: Mutex Verification Routines
6132**
6133** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
6134** are intended for use inside assert() statements.  ^The SQLite core
6135** never uses these routines except inside an assert() and applications
6136** are advised to follow the lead of the core.  ^The SQLite core only
6137** provides implementations for these routines when it is compiled
6138** with the SQLITE_DEBUG flag.  ^External mutex implementations
6139** are only required to provide these routines if SQLITE_DEBUG is
6140** defined and if NDEBUG is not defined.
6141**
6142** ^These routines should return true if the mutex in their argument
6143** is held or not held, respectively, by the calling thread.
6144**
6145** ^The implementation is not required to provide versions of these
6146** routines that actually work. If the implementation does not provide working
6147** versions of these routines, it should at least provide stubs that always
6148** return true so that one does not get spurious assertion failures.
6149**
6150** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
6151** the routine should return 1.   This seems counter-intuitive since
6152** clearly the mutex cannot be held if it does not exist.  But
6153** the reason the mutex does not exist is because the build is not
6154** using mutexes.  And we do not want the assert() containing the
6155** call to sqlite3_mutex_held() to fail, so a non-zero return is
6156** the appropriate thing to do.  ^The sqlite3_mutex_notheld()
6157** interface should also return 1 when given a NULL pointer.
6158*/
6159#ifndef NDEBUG
6160SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
6161SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
6162#endif
6163
6164/*
6165** CAPI3REF: Mutex Types
6166**
6167** The [sqlite3_mutex_alloc()] interface takes a single argument
6168** which is one of these integer constants.
6169**
6170** The set of static mutexes may change from one SQLite release to the
6171** next.  Applications that override the built-in mutex logic must be
6172** prepared to accommodate additional static mutexes.
6173*/
6174#define SQLITE_MUTEX_FAST             0
6175#define SQLITE_MUTEX_RECURSIVE        1
6176#define SQLITE_MUTEX_STATIC_MASTER    2
6177#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
6178#define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
6179#define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
6180#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
6181#define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
6182#define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
6183#define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
6184#define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
6185#define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
6186#define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
6187
6188/*
6189** CAPI3REF: Retrieve the mutex for a database connection
6190**
6191** ^This interface returns a pointer the [sqlite3_mutex] object that
6192** serializes access to the [database connection] given in the argument
6193** when the [threading mode] is Serialized.
6194** ^If the [threading mode] is Single-thread or Multi-thread then this
6195** routine returns a NULL pointer.
6196*/
6197SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
6198
6199/*
6200** CAPI3REF: Low-Level Control Of Database Files
6201**
6202** ^The [sqlite3_file_control()] interface makes a direct call to the
6203** xFileControl method for the [sqlite3_io_methods] object associated
6204** with a particular database identified by the second argument. ^The
6205** name of the database is "main" for the main database or "temp" for the
6206** TEMP database, or the name that appears after the AS keyword for
6207** databases that are added using the [ATTACH] SQL command.
6208** ^A NULL pointer can be used in place of "main" to refer to the
6209** main database file.
6210** ^The third and fourth parameters to this routine
6211** are passed directly through to the second and third parameters of
6212** the xFileControl method.  ^The return value of the xFileControl
6213** method becomes the return value of this routine.
6214**
6215** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
6216** a pointer to the underlying [sqlite3_file] object to be written into
6217** the space pointed to by the 4th parameter.  ^The SQLITE_FCNTL_FILE_POINTER
6218** case is a short-circuit path which does not actually invoke the
6219** underlying sqlite3_io_methods.xFileControl method.
6220**
6221** ^If the second parameter (zDbName) does not match the name of any
6222** open database file, then SQLITE_ERROR is returned.  ^This error
6223** code is not remembered and will not be recalled by [sqlite3_errcode()]
6224** or [sqlite3_errmsg()].  The underlying xFileControl method might
6225** also return SQLITE_ERROR.  There is no way to distinguish between
6226** an incorrect zDbName and an SQLITE_ERROR return from the underlying
6227** xFileControl method.
6228**
6229** See also: [SQLITE_FCNTL_LOCKSTATE]
6230*/
6231SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
6232
6233/*
6234** CAPI3REF: Testing Interface
6235**
6236** ^The sqlite3_test_control() interface is used to read out internal
6237** state of SQLite and to inject faults into SQLite for testing
6238** purposes.  ^The first parameter is an operation code that determines
6239** the number, meaning, and operation of all subsequent parameters.
6240**
6241** This interface is not for use by applications.  It exists solely
6242** for verifying the correct operation of the SQLite library.  Depending
6243** on how the SQLite library is compiled, this interface might not exist.
6244**
6245** The details of the operation codes, their meanings, the parameters
6246** they take, and what they do are all subject to change without notice.
6247** Unlike most of the SQLite API, this function is not guaranteed to
6248** operate consistently from one release to the next.
6249*/
6250SQLITE_API int sqlite3_test_control(int op, ...);
6251
6252/*
6253** CAPI3REF: Testing Interface Operation Codes
6254**
6255** These constants are the valid operation code parameters used
6256** as the first argument to [sqlite3_test_control()].
6257**
6258** These parameters and their meanings are subject to change
6259** without notice.  These values are for testing purposes only.
6260** Applications should not use any of these parameters or the
6261** [sqlite3_test_control()] interface.
6262*/
6263#define SQLITE_TESTCTRL_FIRST                    5
6264#define SQLITE_TESTCTRL_PRNG_SAVE                5
6265#define SQLITE_TESTCTRL_PRNG_RESTORE             6
6266#define SQLITE_TESTCTRL_PRNG_RESET               7
6267#define SQLITE_TESTCTRL_BITVEC_TEST              8
6268#define SQLITE_TESTCTRL_FAULT_INSTALL            9
6269#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
6270#define SQLITE_TESTCTRL_PENDING_BYTE            11
6271#define SQLITE_TESTCTRL_ASSERT                  12
6272#define SQLITE_TESTCTRL_ALWAYS                  13
6273#define SQLITE_TESTCTRL_RESERVE                 14
6274#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
6275#define SQLITE_TESTCTRL_ISKEYWORD               16
6276#define SQLITE_TESTCTRL_SCRATCHMALLOC           17
6277#define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
6278#define SQLITE_TESTCTRL_EXPLAIN_STMT            19
6279#define SQLITE_TESTCTRL_NEVER_CORRUPT           20
6280#define SQLITE_TESTCTRL_VDBE_COVERAGE           21
6281#define SQLITE_TESTCTRL_BYTEORDER               22
6282#define SQLITE_TESTCTRL_ISINIT                  23
6283#define SQLITE_TESTCTRL_LAST                    23
6284
6285/*
6286** CAPI3REF: SQLite Runtime Status
6287**
6288** ^This interface is used to retrieve runtime status information
6289** about the performance of SQLite, and optionally to reset various
6290** highwater marks.  ^The first argument is an integer code for
6291** the specific parameter to measure.  ^(Recognized integer codes
6292** are of the form [status parameters | SQLITE_STATUS_...].)^
6293** ^The current value of the parameter is returned into *pCurrent.
6294** ^The highest recorded value is returned in *pHighwater.  ^If the
6295** resetFlag is true, then the highest record value is reset after
6296** *pHighwater is written.  ^(Some parameters do not record the highest
6297** value.  For those parameters
6298** nothing is written into *pHighwater and the resetFlag is ignored.)^
6299** ^(Other parameters record only the highwater mark and not the current
6300** value.  For these latter parameters nothing is written into *pCurrent.)^
6301**
6302** ^The sqlite3_status() routine returns SQLITE_OK on success and a
6303** non-zero [error code] on failure.
6304**
6305** This routine is threadsafe but is not atomic.  This routine can be
6306** called while other threads are running the same or different SQLite
6307** interfaces.  However the values returned in *pCurrent and
6308** *pHighwater reflect the status of SQLite at different points in time
6309** and it is possible that another thread might change the parameter
6310** in between the times when *pCurrent and *pHighwater are written.
6311**
6312** See also: [sqlite3_db_status()]
6313*/
6314SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
6315
6316
6317/*
6318** CAPI3REF: Status Parameters
6319** KEYWORDS: {status parameters}
6320**
6321** These integer constants designate various run-time status parameters
6322** that can be returned by [sqlite3_status()].
6323**
6324** <dl>
6325** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
6326** <dd>This parameter is the current amount of memory checked out
6327** using [sqlite3_malloc()], either directly or indirectly.  The
6328** figure includes calls made to [sqlite3_malloc()] by the application
6329** and internal memory usage by the SQLite library.  Scratch memory
6330** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
6331** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
6332** this parameter.  The amount returned is the sum of the allocation
6333** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
6334**
6335** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
6336** <dd>This parameter records the largest memory allocation request
6337** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
6338** internal equivalents).  Only the value returned in the
6339** *pHighwater parameter to [sqlite3_status()] is of interest.
6340** The value written into the *pCurrent parameter is undefined.</dd>)^
6341**
6342** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
6343** <dd>This parameter records the number of separate memory allocations
6344** currently checked out.</dd>)^
6345**
6346** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
6347** <dd>This parameter returns the number of pages used out of the
6348** [pagecache memory allocator] that was configured using
6349** [SQLITE_CONFIG_PAGECACHE].  The
6350** value returned is in pages, not in bytes.</dd>)^
6351**
6352** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
6353** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
6354** <dd>This parameter returns the number of bytes of page cache
6355** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
6356** buffer and where forced to overflow to [sqlite3_malloc()].  The
6357** returned value includes allocations that overflowed because they
6358** where too large (they were larger than the "sz" parameter to
6359** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
6360** no space was left in the page cache.</dd>)^
6361**
6362** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
6363** <dd>This parameter records the largest memory allocation request
6364** handed to [pagecache memory allocator].  Only the value returned in the
6365** *pHighwater parameter to [sqlite3_status()] is of interest.
6366** The value written into the *pCurrent parameter is undefined.</dd>)^
6367**
6368** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
6369** <dd>This parameter returns the number of allocations used out of the
6370** [scratch memory allocator] configured using
6371** [SQLITE_CONFIG_SCRATCH].  The value returned is in allocations, not
6372** in bytes.  Since a single thread may only have one scratch allocation
6373** outstanding at time, this parameter also reports the number of threads
6374** using scratch memory at the same time.</dd>)^
6375**
6376** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
6377** <dd>This parameter returns the number of bytes of scratch memory
6378** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
6379** buffer and where forced to overflow to [sqlite3_malloc()].  The values
6380** returned include overflows because the requested allocation was too
6381** larger (that is, because the requested allocation was larger than the
6382** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
6383** slots were available.
6384** </dd>)^
6385**
6386** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
6387** <dd>This parameter records the largest memory allocation request
6388** handed to [scratch memory allocator].  Only the value returned in the
6389** *pHighwater parameter to [sqlite3_status()] is of interest.
6390** The value written into the *pCurrent parameter is undefined.</dd>)^
6391**
6392** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
6393** <dd>This parameter records the deepest parser stack.  It is only
6394** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
6395** </dl>
6396**
6397** New status parameters may be added from time to time.
6398*/
6399#define SQLITE_STATUS_MEMORY_USED          0
6400#define SQLITE_STATUS_PAGECACHE_USED       1
6401#define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
6402#define SQLITE_STATUS_SCRATCH_USED         3
6403#define SQLITE_STATUS_SCRATCH_OVERFLOW     4
6404#define SQLITE_STATUS_MALLOC_SIZE          5
6405#define SQLITE_STATUS_PARSER_STACK         6
6406#define SQLITE_STATUS_PAGECACHE_SIZE       7
6407#define SQLITE_STATUS_SCRATCH_SIZE         8
6408#define SQLITE_STATUS_MALLOC_COUNT         9
6409
6410/*
6411** CAPI3REF: Database Connection Status
6412**
6413** ^This interface is used to retrieve runtime status information
6414** about a single [database connection].  ^The first argument is the
6415** database connection object to be interrogated.  ^The second argument
6416** is an integer constant, taken from the set of
6417** [SQLITE_DBSTATUS options], that
6418** determines the parameter to interrogate.  The set of
6419** [SQLITE_DBSTATUS options] is likely
6420** to grow in future releases of SQLite.
6421**
6422** ^The current value of the requested parameter is written into *pCur
6423** and the highest instantaneous value is written into *pHiwtr.  ^If
6424** the resetFlg is true, then the highest instantaneous value is
6425** reset back down to the current value.
6426**
6427** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
6428** non-zero [error code] on failure.
6429**
6430** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
6431*/
6432SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
6433
6434/*
6435** CAPI3REF: Status Parameters for database connections
6436** KEYWORDS: {SQLITE_DBSTATUS options}
6437**
6438** These constants are the available integer "verbs" that can be passed as
6439** the second argument to the [sqlite3_db_status()] interface.
6440**
6441** New verbs may be added in future releases of SQLite. Existing verbs
6442** might be discontinued. Applications should check the return code from
6443** [sqlite3_db_status()] to make sure that the call worked.
6444** The [sqlite3_db_status()] interface will return a non-zero error code
6445** if a discontinued or unsupported verb is invoked.
6446**
6447** <dl>
6448** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
6449** <dd>This parameter returns the number of lookaside memory slots currently
6450** checked out.</dd>)^
6451**
6452** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
6453** <dd>This parameter returns the number malloc attempts that were
6454** satisfied using lookaside memory. Only the high-water value is meaningful;
6455** the current value is always zero.)^
6456**
6457** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
6458** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
6459** <dd>This parameter returns the number malloc attempts that might have
6460** been satisfied using lookaside memory but failed due to the amount of
6461** memory requested being larger than the lookaside slot size.
6462** Only the high-water value is meaningful;
6463** the current value is always zero.)^
6464**
6465** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
6466** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
6467** <dd>This parameter returns the number malloc attempts that might have
6468** been satisfied using lookaside memory but failed due to all lookaside
6469** memory already being in use.
6470** Only the high-water value is meaningful;
6471** the current value is always zero.)^
6472**
6473** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
6474** <dd>This parameter returns the approximate number of of bytes of heap
6475** memory used by all pager caches associated with the database connection.)^
6476** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
6477**
6478** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
6479** <dd>This parameter returns the approximate number of of bytes of heap
6480** memory used to store the schema for all databases associated
6481** with the connection - main, temp, and any [ATTACH]-ed databases.)^
6482** ^The full amount of memory used by the schemas is reported, even if the
6483** schema memory is shared with other database connections due to
6484** [shared cache mode] being enabled.
6485** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
6486**
6487** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
6488** <dd>This parameter returns the approximate number of of bytes of heap
6489** and lookaside memory used by all prepared statements associated with
6490** the database connection.)^
6491** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
6492** </dd>
6493**
6494** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
6495** <dd>This parameter returns the number of pager cache hits that have
6496** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
6497** is always 0.
6498** </dd>
6499**
6500** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
6501** <dd>This parameter returns the number of pager cache misses that have
6502** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
6503** is always 0.
6504** </dd>
6505**
6506** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
6507** <dd>This parameter returns the number of dirty cache entries that have
6508** been written to disk. Specifically, the number of pages written to the
6509** wal file in wal mode databases, or the number of pages written to the
6510** database file in rollback mode databases. Any pages written as part of
6511** transaction rollback or database recovery operations are not included.
6512** If an IO or other error occurs while writing a page to disk, the effect
6513** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
6514** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
6515** </dd>
6516**
6517** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
6518** <dd>This parameter returns zero for the current value if and only if
6519** all foreign key constraints (deferred or immediate) have been
6520** resolved.)^  ^The highwater mark is always 0.
6521** </dd>
6522** </dl>
6523*/
6524#define SQLITE_DBSTATUS_LOOKASIDE_USED       0
6525#define SQLITE_DBSTATUS_CACHE_USED           1
6526#define SQLITE_DBSTATUS_SCHEMA_USED          2
6527#define SQLITE_DBSTATUS_STMT_USED            3
6528#define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
6529#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
6530#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
6531#define SQLITE_DBSTATUS_CACHE_HIT            7
6532#define SQLITE_DBSTATUS_CACHE_MISS           8
6533#define SQLITE_DBSTATUS_CACHE_WRITE          9
6534#define SQLITE_DBSTATUS_DEFERRED_FKS        10
6535#define SQLITE_DBSTATUS_MAX                 10   /* Largest defined DBSTATUS */
6536
6537
6538/*
6539** CAPI3REF: Prepared Statement Status
6540**
6541** ^(Each prepared statement maintains various
6542** [SQLITE_STMTSTATUS counters] that measure the number
6543** of times it has performed specific operations.)^  These counters can
6544** be used to monitor the performance characteristics of the prepared
6545** statements.  For example, if the number of table steps greatly exceeds
6546** the number of table searches or result rows, that would tend to indicate
6547** that the prepared statement is using a full table scan rather than
6548** an index.
6549**
6550** ^(This interface is used to retrieve and reset counter values from
6551** a [prepared statement].  The first argument is the prepared statement
6552** object to be interrogated.  The second argument
6553** is an integer code for a specific [SQLITE_STMTSTATUS counter]
6554** to be interrogated.)^
6555** ^The current value of the requested counter is returned.
6556** ^If the resetFlg is true, then the counter is reset to zero after this
6557** interface call returns.
6558**
6559** See also: [sqlite3_status()] and [sqlite3_db_status()].
6560*/
6561SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
6562
6563/*
6564** CAPI3REF: Status Parameters for prepared statements
6565** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
6566**
6567** These preprocessor macros define integer codes that name counter
6568** values associated with the [sqlite3_stmt_status()] interface.
6569** The meanings of the various counters are as follows:
6570**
6571** <dl>
6572** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
6573** <dd>^This is the number of times that SQLite has stepped forward in
6574** a table as part of a full table scan.  Large numbers for this counter
6575** may indicate opportunities for performance improvement through
6576** careful use of indices.</dd>
6577**
6578** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
6579** <dd>^This is the number of sort operations that have occurred.
6580** A non-zero value in this counter may indicate an opportunity to
6581** improvement performance through careful use of indices.</dd>
6582**
6583** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
6584** <dd>^This is the number of rows inserted into transient indices that
6585** were created automatically in order to help joins run faster.
6586** A non-zero value in this counter may indicate an opportunity to
6587** improvement performance by adding permanent indices that do not
6588** need to be reinitialized each time the statement is run.</dd>
6589**
6590** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
6591** <dd>^This is the number of virtual machine operations executed
6592** by the prepared statement if that number is less than or equal
6593** to 2147483647.  The number of virtual machine operations can be
6594** used as a proxy for the total work done by the prepared statement.
6595** If the number of virtual machine operations exceeds 2147483647
6596** then the value returned by this statement status code is undefined.
6597** </dd>
6598** </dl>
6599*/
6600#define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
6601#define SQLITE_STMTSTATUS_SORT              2
6602#define SQLITE_STMTSTATUS_AUTOINDEX         3
6603#define SQLITE_STMTSTATUS_VM_STEP           4
6604
6605/*
6606** CAPI3REF: Custom Page Cache Object
6607**
6608** The sqlite3_pcache type is opaque.  It is implemented by
6609** the pluggable module.  The SQLite core has no knowledge of
6610** its size or internal structure and never deals with the
6611** sqlite3_pcache object except by holding and passing pointers
6612** to the object.
6613**
6614** See [sqlite3_pcache_methods2] for additional information.
6615*/
6616typedef struct sqlite3_pcache sqlite3_pcache;
6617
6618/*
6619** CAPI3REF: Custom Page Cache Object
6620**
6621** The sqlite3_pcache_page object represents a single page in the
6622** page cache.  The page cache will allocate instances of this
6623** object.  Various methods of the page cache use pointers to instances
6624** of this object as parameters or as their return value.
6625**
6626** See [sqlite3_pcache_methods2] for additional information.
6627*/
6628typedef struct sqlite3_pcache_page sqlite3_pcache_page;
6629struct sqlite3_pcache_page {
6630  void *pBuf;        /* The content of the page */
6631  void *pExtra;      /* Extra information associated with the page */
6632};
6633
6634/*
6635** CAPI3REF: Application Defined Page Cache.
6636** KEYWORDS: {page cache}
6637**
6638** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
6639** register an alternative page cache implementation by passing in an
6640** instance of the sqlite3_pcache_methods2 structure.)^
6641** In many applications, most of the heap memory allocated by
6642** SQLite is used for the page cache.
6643** By implementing a
6644** custom page cache using this API, an application can better control
6645** the amount of memory consumed by SQLite, the way in which
6646** that memory is allocated and released, and the policies used to
6647** determine exactly which parts of a database file are cached and for
6648** how long.
6649**
6650** The alternative page cache mechanism is an
6651** extreme measure that is only needed by the most demanding applications.
6652** The built-in page cache is recommended for most uses.
6653**
6654** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
6655** internal buffer by SQLite within the call to [sqlite3_config].  Hence
6656** the application may discard the parameter after the call to
6657** [sqlite3_config()] returns.)^
6658**
6659** [[the xInit() page cache method]]
6660** ^(The xInit() method is called once for each effective
6661** call to [sqlite3_initialize()])^
6662** (usually only once during the lifetime of the process). ^(The xInit()
6663** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
6664** The intent of the xInit() method is to set up global data structures
6665** required by the custom page cache implementation.
6666** ^(If the xInit() method is NULL, then the
6667** built-in default page cache is used instead of the application defined
6668** page cache.)^
6669**
6670** [[the xShutdown() page cache method]]
6671** ^The xShutdown() method is called by [sqlite3_shutdown()].
6672** It can be used to clean up
6673** any outstanding resources before process shutdown, if required.
6674** ^The xShutdown() method may be NULL.
6675**
6676** ^SQLite automatically serializes calls to the xInit method,
6677** so the xInit method need not be threadsafe.  ^The
6678** xShutdown method is only called from [sqlite3_shutdown()] so it does
6679** not need to be threadsafe either.  All other methods must be threadsafe
6680** in multithreaded applications.
6681**
6682** ^SQLite will never invoke xInit() more than once without an intervening
6683** call to xShutdown().
6684**
6685** [[the xCreate() page cache methods]]
6686** ^SQLite invokes the xCreate() method to construct a new cache instance.
6687** SQLite will typically create one cache instance for each open database file,
6688** though this is not guaranteed. ^The
6689** first parameter, szPage, is the size in bytes of the pages that must
6690** be allocated by the cache.  ^szPage will always a power of two.  ^The
6691** second parameter szExtra is a number of bytes of extra storage
6692** associated with each page cache entry.  ^The szExtra parameter will
6693** a number less than 250.  SQLite will use the
6694** extra szExtra bytes on each page to store metadata about the underlying
6695** database page on disk.  The value passed into szExtra depends
6696** on the SQLite version, the target platform, and how SQLite was compiled.
6697** ^The third argument to xCreate(), bPurgeable, is true if the cache being
6698** created will be used to cache database pages of a file stored on disk, or
6699** false if it is used for an in-memory database. The cache implementation
6700** does not have to do anything special based with the value of bPurgeable;
6701** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
6702** never invoke xUnpin() except to deliberately delete a page.
6703** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
6704** false will always have the "discard" flag set to true.
6705** ^Hence, a cache created with bPurgeable false will
6706** never contain any unpinned pages.
6707**
6708** [[the xCachesize() page cache method]]
6709** ^(The xCachesize() method may be called at any time by SQLite to set the
6710** suggested maximum cache-size (number of pages stored by) the cache
6711** instance passed as the first argument. This is the value configured using
6712** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
6713** parameter, the implementation is not required to do anything with this
6714** value; it is advisory only.
6715**
6716** [[the xPagecount() page cache methods]]
6717** The xPagecount() method must return the number of pages currently
6718** stored in the cache, both pinned and unpinned.
6719**
6720** [[the xFetch() page cache methods]]
6721** The xFetch() method locates a page in the cache and returns a pointer to
6722** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
6723** The pBuf element of the returned sqlite3_pcache_page object will be a
6724** pointer to a buffer of szPage bytes used to store the content of a
6725** single database page.  The pExtra element of sqlite3_pcache_page will be
6726** a pointer to the szExtra bytes of extra storage that SQLite has requested
6727** for each entry in the page cache.
6728**
6729** The page to be fetched is determined by the key. ^The minimum key value
6730** is 1.  After it has been retrieved using xFetch, the page is considered
6731** to be "pinned".
6732**
6733** If the requested page is already in the page cache, then the page cache
6734** implementation must return a pointer to the page buffer with its content
6735** intact.  If the requested page is not already in the cache, then the
6736** cache implementation should use the value of the createFlag
6737** parameter to help it determined what action to take:
6738**
6739** <table border=1 width=85% align=center>
6740** <tr><th> createFlag <th> Behavior when page is not already in cache
6741** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
6742** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
6743**                 Otherwise return NULL.
6744** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
6745**                 NULL if allocating a new page is effectively impossible.
6746** </table>
6747**
6748** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
6749** will only use a createFlag of 2 after a prior call with a createFlag of 1
6750** failed.)^  In between the to xFetch() calls, SQLite may
6751** attempt to unpin one or more cache pages by spilling the content of
6752** pinned pages to disk and synching the operating system disk cache.
6753**
6754** [[the xUnpin() page cache method]]
6755** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
6756** as its second argument.  If the third parameter, discard, is non-zero,
6757** then the page must be evicted from the cache.
6758** ^If the discard parameter is
6759** zero, then the page may be discarded or retained at the discretion of
6760** page cache implementation. ^The page cache implementation
6761** may choose to evict unpinned pages at any time.
6762**
6763** The cache must not perform any reference counting. A single
6764** call to xUnpin() unpins the page regardless of the number of prior calls
6765** to xFetch().
6766**
6767** [[the xRekey() page cache methods]]
6768** The xRekey() method is used to change the key value associated with the
6769** page passed as the second argument. If the cache
6770** previously contains an entry associated with newKey, it must be
6771** discarded. ^Any prior cache entry associated with newKey is guaranteed not
6772** to be pinned.
6773**
6774** When SQLite calls the xTruncate() method, the cache must discard all
6775** existing cache entries with page numbers (keys) greater than or equal
6776** to the value of the iLimit parameter passed to xTruncate(). If any
6777** of these pages are pinned, they are implicitly unpinned, meaning that
6778** they can be safely discarded.
6779**
6780** [[the xDestroy() page cache method]]
6781** ^The xDestroy() method is used to delete a cache allocated by xCreate().
6782** All resources associated with the specified cache should be freed. ^After
6783** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
6784** handle invalid, and will not use it with any other sqlite3_pcache_methods2
6785** functions.
6786**
6787** [[the xShrink() page cache method]]
6788** ^SQLite invokes the xShrink() method when it wants the page cache to
6789** free up as much of heap memory as possible.  The page cache implementation
6790** is not obligated to free any memory, but well-behaved implementations should
6791** do their best.
6792*/
6793typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
6794struct sqlite3_pcache_methods2 {
6795  int iVersion;
6796  void *pArg;
6797  int (*xInit)(void*);
6798  void (*xShutdown)(void*);
6799  sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
6800  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6801  int (*xPagecount)(sqlite3_pcache*);
6802  sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6803  void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
6804  void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
6805      unsigned oldKey, unsigned newKey);
6806  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6807  void (*xDestroy)(sqlite3_pcache*);
6808  void (*xShrink)(sqlite3_pcache*);
6809};
6810
6811/*
6812** This is the obsolete pcache_methods object that has now been replaced
6813** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
6814** retained in the header file for backwards compatibility only.
6815*/
6816typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
6817struct sqlite3_pcache_methods {
6818  void *pArg;
6819  int (*xInit)(void*);
6820  void (*xShutdown)(void*);
6821  sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
6822  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6823  int (*xPagecount)(sqlite3_pcache*);
6824  void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6825  void (*xUnpin)(sqlite3_pcache*, void*, int discard);
6826  void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
6827  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6828  void (*xDestroy)(sqlite3_pcache*);
6829};
6830
6831
6832/*
6833** CAPI3REF: Online Backup Object
6834**
6835** The sqlite3_backup object records state information about an ongoing
6836** online backup operation.  ^The sqlite3_backup object is created by
6837** a call to [sqlite3_backup_init()] and is destroyed by a call to
6838** [sqlite3_backup_finish()].
6839**
6840** See Also: [Using the SQLite Online Backup API]
6841*/
6842typedef struct sqlite3_backup sqlite3_backup;
6843
6844/*
6845** CAPI3REF: Online Backup API.
6846**
6847** The backup API copies the content of one database into another.
6848** It is useful either for creating backups of databases or
6849** for copying in-memory databases to or from persistent files.
6850**
6851** See Also: [Using the SQLite Online Backup API]
6852**
6853** ^SQLite holds a write transaction open on the destination database file
6854** for the duration of the backup operation.
6855** ^The source database is read-locked only while it is being read;
6856** it is not locked continuously for the entire backup operation.
6857** ^Thus, the backup may be performed on a live source database without
6858** preventing other database connections from
6859** reading or writing to the source database while the backup is underway.
6860**
6861** ^(To perform a backup operation:
6862**   <ol>
6863**     <li><b>sqlite3_backup_init()</b> is called once to initialize the
6864**         backup,
6865**     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
6866**         the data between the two databases, and finally
6867**     <li><b>sqlite3_backup_finish()</b> is called to release all resources
6868**         associated with the backup operation.
6869**   </ol>)^
6870** There should be exactly one call to sqlite3_backup_finish() for each
6871** successful call to sqlite3_backup_init().
6872**
6873** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
6874**
6875** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
6876** [database connection] associated with the destination database
6877** and the database name, respectively.
6878** ^The database name is "main" for the main database, "temp" for the
6879** temporary database, or the name specified after the AS keyword in
6880** an [ATTACH] statement for an attached database.
6881** ^The S and M arguments passed to
6882** sqlite3_backup_init(D,N,S,M) identify the [database connection]
6883** and database name of the source database, respectively.
6884** ^The source and destination [database connections] (parameters S and D)
6885** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
6886** an error.
6887**
6888** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
6889** returned and an error code and error message are stored in the
6890** destination [database connection] D.
6891** ^The error code and message for the failed call to sqlite3_backup_init()
6892** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
6893** [sqlite3_errmsg16()] functions.
6894** ^A successful call to sqlite3_backup_init() returns a pointer to an
6895** [sqlite3_backup] object.
6896** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
6897** sqlite3_backup_finish() functions to perform the specified backup
6898** operation.
6899**
6900** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
6901**
6902** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
6903** the source and destination databases specified by [sqlite3_backup] object B.
6904** ^If N is negative, all remaining source pages are copied.
6905** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
6906** are still more pages to be copied, then the function returns [SQLITE_OK].
6907** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
6908** from source to destination, then it returns [SQLITE_DONE].
6909** ^If an error occurs while running sqlite3_backup_step(B,N),
6910** then an [error code] is returned. ^As well as [SQLITE_OK] and
6911** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
6912** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
6913** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
6914**
6915** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
6916** <ol>
6917** <li> the destination database was opened read-only, or
6918** <li> the destination database is using write-ahead-log journaling
6919** and the destination and source page sizes differ, or
6920** <li> the destination database is an in-memory database and the
6921** destination and source page sizes differ.
6922** </ol>)^
6923**
6924** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
6925** the [sqlite3_busy_handler | busy-handler function]
6926** is invoked (if one is specified). ^If the
6927** busy-handler returns non-zero before the lock is available, then
6928** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
6929** sqlite3_backup_step() can be retried later. ^If the source
6930** [database connection]
6931** is being used to write to the source database when sqlite3_backup_step()
6932** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
6933** case the call to sqlite3_backup_step() can be retried later on. ^(If
6934** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
6935** [SQLITE_READONLY] is returned, then
6936** there is no point in retrying the call to sqlite3_backup_step(). These
6937** errors are considered fatal.)^  The application must accept
6938** that the backup operation has failed and pass the backup operation handle
6939** to the sqlite3_backup_finish() to release associated resources.
6940**
6941** ^The first call to sqlite3_backup_step() obtains an exclusive lock
6942** on the destination file. ^The exclusive lock is not released until either
6943** sqlite3_backup_finish() is called or the backup operation is complete
6944** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
6945** sqlite3_backup_step() obtains a [shared lock] on the source database that
6946** lasts for the duration of the sqlite3_backup_step() call.
6947** ^Because the source database is not locked between calls to
6948** sqlite3_backup_step(), the source database may be modified mid-way
6949** through the backup process.  ^If the source database is modified by an
6950** external process or via a database connection other than the one being
6951** used by the backup operation, then the backup will be automatically
6952** restarted by the next call to sqlite3_backup_step(). ^If the source
6953** database is modified by the using the same database connection as is used
6954** by the backup operation, then the backup database is automatically
6955** updated at the same time.
6956**
6957** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
6958**
6959** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
6960** application wishes to abandon the backup operation, the application
6961** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
6962** ^The sqlite3_backup_finish() interfaces releases all
6963** resources associated with the [sqlite3_backup] object.
6964** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
6965** active write-transaction on the destination database is rolled back.
6966** The [sqlite3_backup] object is invalid
6967** and may not be used following a call to sqlite3_backup_finish().
6968**
6969** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
6970** sqlite3_backup_step() errors occurred, regardless or whether or not
6971** sqlite3_backup_step() completed.
6972** ^If an out-of-memory condition or IO error occurred during any prior
6973** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
6974** sqlite3_backup_finish() returns the corresponding [error code].
6975**
6976** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
6977** is not a permanent error and does not affect the return value of
6978** sqlite3_backup_finish().
6979**
6980** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]
6981** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
6982**
6983** ^Each call to sqlite3_backup_step() sets two values inside
6984** the [sqlite3_backup] object: the number of pages still to be backed
6985** up and the total number of pages in the source database file.
6986** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
6987** retrieve these two values, respectively.
6988**
6989** ^The values returned by these functions are only updated by
6990** sqlite3_backup_step(). ^If the source database is modified during a backup
6991** operation, then the values are not updated to account for any extra
6992** pages that need to be updated or the size of the source database file
6993** changing.
6994**
6995** <b>Concurrent Usage of Database Handles</b>
6996**
6997** ^The source [database connection] may be used by the application for other
6998** purposes while a backup operation is underway or being initialized.
6999** ^If SQLite is compiled and configured to support threadsafe database
7000** connections, then the source database connection may be used concurrently
7001** from within other threads.
7002**
7003** However, the application must guarantee that the destination
7004** [database connection] is not passed to any other API (by any thread) after
7005** sqlite3_backup_init() is called and before the corresponding call to
7006** sqlite3_backup_finish().  SQLite does not currently check to see
7007** if the application incorrectly accesses the destination [database connection]
7008** and so no error code is reported, but the operations may malfunction
7009** nevertheless.  Use of the destination database connection while a
7010** backup is in progress might also also cause a mutex deadlock.
7011**
7012** If running in [shared cache mode], the application must
7013** guarantee that the shared cache used by the destination database
7014** is not accessed while the backup is running. In practice this means
7015** that the application must guarantee that the disk file being
7016** backed up to is not accessed by any connection within the process,
7017** not just the specific connection that was passed to sqlite3_backup_init().
7018**
7019** The [sqlite3_backup] object itself is partially threadsafe. Multiple
7020** threads may safely make multiple concurrent calls to sqlite3_backup_step().
7021** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
7022** APIs are not strictly speaking threadsafe. If they are invoked at the
7023** same time as another thread is invoking sqlite3_backup_step() it is
7024** possible that they return invalid values.
7025*/
7026SQLITE_API sqlite3_backup *sqlite3_backup_init(
7027  sqlite3 *pDest,                        /* Destination database handle */
7028  const char *zDestName,                 /* Destination database name */
7029  sqlite3 *pSource,                      /* Source database handle */
7030  const char *zSourceName                /* Source database name */
7031);
7032SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
7033SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
7034SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
7035SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
7036
7037/*
7038** CAPI3REF: Unlock Notification
7039**
7040** ^When running in shared-cache mode, a database operation may fail with
7041** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
7042** individual tables within the shared-cache cannot be obtained. See
7043** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
7044** ^This API may be used to register a callback that SQLite will invoke
7045** when the connection currently holding the required lock relinquishes it.
7046** ^This API is only available if the library was compiled with the
7047** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
7048**
7049** See Also: [Using the SQLite Unlock Notification Feature].
7050**
7051** ^Shared-cache locks are released when a database connection concludes
7052** its current transaction, either by committing it or rolling it back.
7053**
7054** ^When a connection (known as the blocked connection) fails to obtain a
7055** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
7056** identity of the database connection (the blocking connection) that
7057** has locked the required resource is stored internally. ^After an
7058** application receives an SQLITE_LOCKED error, it may call the
7059** sqlite3_unlock_notify() method with the blocked connection handle as
7060** the first argument to register for a callback that will be invoked
7061** when the blocking connections current transaction is concluded. ^The
7062** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
7063** call that concludes the blocking connections transaction.
7064**
7065** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
7066** there is a chance that the blocking connection will have already
7067** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
7068** If this happens, then the specified callback is invoked immediately,
7069** from within the call to sqlite3_unlock_notify().)^
7070**
7071** ^If the blocked connection is attempting to obtain a write-lock on a
7072** shared-cache table, and more than one other connection currently holds
7073** a read-lock on the same table, then SQLite arbitrarily selects one of
7074** the other connections to use as the blocking connection.
7075**
7076** ^(There may be at most one unlock-notify callback registered by a
7077** blocked connection. If sqlite3_unlock_notify() is called when the
7078** blocked connection already has a registered unlock-notify callback,
7079** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
7080** called with a NULL pointer as its second argument, then any existing
7081** unlock-notify callback is canceled. ^The blocked connections
7082** unlock-notify callback may also be canceled by closing the blocked
7083** connection using [sqlite3_close()].
7084**
7085** The unlock-notify callback is not reentrant. If an application invokes
7086** any sqlite3_xxx API functions from within an unlock-notify callback, a
7087** crash or deadlock may be the result.
7088**
7089** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
7090** returns SQLITE_OK.
7091**
7092** <b>Callback Invocation Details</b>
7093**
7094** When an unlock-notify callback is registered, the application provides a
7095** single void* pointer that is passed to the callback when it is invoked.
7096** However, the signature of the callback function allows SQLite to pass
7097** it an array of void* context pointers. The first argument passed to
7098** an unlock-notify callback is a pointer to an array of void* pointers,
7099** and the second is the number of entries in the array.
7100**
7101** When a blocking connections transaction is concluded, there may be
7102** more than one blocked connection that has registered for an unlock-notify
7103** callback. ^If two or more such blocked connections have specified the
7104** same callback function, then instead of invoking the callback function
7105** multiple times, it is invoked once with the set of void* context pointers
7106** specified by the blocked connections bundled together into an array.
7107** This gives the application an opportunity to prioritize any actions
7108** related to the set of unblocked database connections.
7109**
7110** <b>Deadlock Detection</b>
7111**
7112** Assuming that after registering for an unlock-notify callback a
7113** database waits for the callback to be issued before taking any further
7114** action (a reasonable assumption), then using this API may cause the
7115** application to deadlock. For example, if connection X is waiting for
7116** connection Y's transaction to be concluded, and similarly connection
7117** Y is waiting on connection X's transaction, then neither connection
7118** will proceed and the system may remain deadlocked indefinitely.
7119**
7120** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
7121** detection. ^If a given call to sqlite3_unlock_notify() would put the
7122** system in a deadlocked state, then SQLITE_LOCKED is returned and no
7123** unlock-notify callback is registered. The system is said to be in
7124** a deadlocked state if connection A has registered for an unlock-notify
7125** callback on the conclusion of connection B's transaction, and connection
7126** B has itself registered for an unlock-notify callback when connection
7127** A's transaction is concluded. ^Indirect deadlock is also detected, so
7128** the system is also considered to be deadlocked if connection B has
7129** registered for an unlock-notify callback on the conclusion of connection
7130** C's transaction, where connection C is waiting on connection A. ^Any
7131** number of levels of indirection are allowed.
7132**
7133** <b>The "DROP TABLE" Exception</b>
7134**
7135** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
7136** always appropriate to call sqlite3_unlock_notify(). There is however,
7137** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
7138** SQLite checks if there are any currently executing SELECT statements
7139** that belong to the same connection. If there are, SQLITE_LOCKED is
7140** returned. In this case there is no "blocking connection", so invoking
7141** sqlite3_unlock_notify() results in the unlock-notify callback being
7142** invoked immediately. If the application then re-attempts the "DROP TABLE"
7143** or "DROP INDEX" query, an infinite loop might be the result.
7144**
7145** One way around this problem is to check the extended error code returned
7146** by an sqlite3_step() call. ^(If there is a blocking connection, then the
7147** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
7148** the special "DROP TABLE/INDEX" case, the extended error code is just
7149** SQLITE_LOCKED.)^
7150*/
7151SQLITE_API int sqlite3_unlock_notify(
7152  sqlite3 *pBlocked,                          /* Waiting connection */
7153  void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
7154  void *pNotifyArg                            /* Argument to pass to xNotify */
7155);
7156
7157
7158/*
7159** CAPI3REF: String Comparison
7160**
7161** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
7162** and extensions to compare the contents of two buffers containing UTF-8
7163** strings in a case-independent fashion, using the same definition of "case
7164** independence" that SQLite uses internally when comparing identifiers.
7165*/
7166SQLITE_API int sqlite3_stricmp(const char *, const char *);
7167SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
7168
7169/*
7170** CAPI3REF: String Globbing
7171*
7172** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches
7173** the glob pattern P, and it returns non-zero if string X does not match
7174** the glob pattern P.  ^The definition of glob pattern matching used in
7175** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
7176** SQL dialect used by SQLite.  ^The sqlite3_strglob(P,X) function is case
7177** sensitive.
7178**
7179** Note that this routine returns zero on a match and non-zero if the strings
7180** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
7181*/
7182SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
7183
7184/*
7185** CAPI3REF: Error Logging Interface
7186**
7187** ^The [sqlite3_log()] interface writes a message into the [error log]
7188** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
7189** ^If logging is enabled, the zFormat string and subsequent arguments are
7190** used with [sqlite3_snprintf()] to generate the final output string.
7191**
7192** The sqlite3_log() interface is intended for use by extensions such as
7193** virtual tables, collating functions, and SQL functions.  While there is
7194** nothing to prevent an application from calling sqlite3_log(), doing so
7195** is considered bad form.
7196**
7197** The zFormat string must not be NULL.
7198**
7199** To avoid deadlocks and other threading problems, the sqlite3_log() routine
7200** will not use dynamically allocated memory.  The log message is stored in
7201** a fixed-length buffer on the stack.  If the log message is longer than
7202** a few hundred characters, it will be truncated to the length of the
7203** buffer.
7204*/
7205SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
7206
7207/*
7208** CAPI3REF: Write-Ahead Log Commit Hook
7209**
7210** ^The [sqlite3_wal_hook()] function is used to register a callback that
7211** will be invoked each time a database connection commits data to a
7212** [write-ahead log] (i.e. whenever a transaction is committed in
7213** [journal_mode | journal_mode=WAL mode]).
7214**
7215** ^The callback is invoked by SQLite after the commit has taken place and
7216** the associated write-lock on the database released, so the implementation
7217** may read, write or [checkpoint] the database as required.
7218**
7219** ^The first parameter passed to the callback function when it is invoked
7220** is a copy of the third parameter passed to sqlite3_wal_hook() when
7221** registering the callback. ^The second is a copy of the database handle.
7222** ^The third parameter is the name of the database that was written to -
7223** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
7224** is the number of pages currently in the write-ahead log file,
7225** including those that were just committed.
7226**
7227** The callback function should normally return [SQLITE_OK].  ^If an error
7228** code is returned, that error will propagate back up through the
7229** SQLite code base to cause the statement that provoked the callback
7230** to report an error, though the commit will have still occurred. If the
7231** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
7232** that does not correspond to any valid SQLite error code, the results
7233** are undefined.
7234**
7235** A single database handle may have at most a single write-ahead log callback
7236** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
7237** previously registered write-ahead log callback. ^Note that the
7238** [sqlite3_wal_autocheckpoint()] interface and the
7239** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
7240** those overwrite any prior [sqlite3_wal_hook()] settings.
7241*/
7242SQLITE_API void *sqlite3_wal_hook(
7243  sqlite3*,
7244  int(*)(void *,sqlite3*,const char*,int),
7245  void*
7246);
7247
7248/*
7249** CAPI3REF: Configure an auto-checkpoint
7250**
7251** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
7252** [sqlite3_wal_hook()] that causes any database on [database connection] D
7253** to automatically [checkpoint]
7254** after committing a transaction if there are N or
7255** more frames in the [write-ahead log] file.  ^Passing zero or
7256** a negative value as the nFrame parameter disables automatic
7257** checkpoints entirely.
7258**
7259** ^The callback registered by this function replaces any existing callback
7260** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
7261** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
7262** configured by this function.
7263**
7264** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
7265** from SQL.
7266**
7267** ^Checkpoints initiated by this mechanism are
7268** [sqlite3_wal_checkpoint_v2|PASSIVE].
7269**
7270** ^Every new [database connection] defaults to having the auto-checkpoint
7271** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
7272** pages.  The use of this interface
7273** is only necessary if the default setting is found to be suboptimal
7274** for a particular application.
7275*/
7276SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
7277
7278/*
7279** CAPI3REF: Checkpoint a database
7280**
7281** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
7282** on [database connection] D to be [checkpointed].  ^If X is NULL or an
7283** empty string, then a checkpoint is run on all databases of
7284** connection D.  ^If the database connection D is not in
7285** [WAL | write-ahead log mode] then this interface is a harmless no-op.
7286** ^The [sqlite3_wal_checkpoint(D,X)] interface initiates a
7287** [sqlite3_wal_checkpoint_v2|PASSIVE] checkpoint.
7288** Use the [sqlite3_wal_checkpoint_v2()] interface to get a FULL
7289** or RESET checkpoint.
7290**
7291** ^The [wal_checkpoint pragma] can be used to invoke this interface
7292** from SQL.  ^The [sqlite3_wal_autocheckpoint()] interface and the
7293** [wal_autocheckpoint pragma] can be used to cause this interface to be
7294** run whenever the WAL reaches a certain size threshold.
7295**
7296** See also: [sqlite3_wal_checkpoint_v2()]
7297*/
7298SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
7299
7300/*
7301** CAPI3REF: Checkpoint a database
7302**
7303** Run a checkpoint operation on WAL database zDb attached to database
7304** handle db. The specific operation is determined by the value of the
7305** eMode parameter:
7306**
7307** <dl>
7308** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
7309**   Checkpoint as many frames as possible without waiting for any database
7310**   readers or writers to finish. Sync the db file if all frames in the log
7311**   are checkpointed. This mode is the same as calling
7312**   sqlite3_wal_checkpoint(). The [sqlite3_busy_handler|busy-handler callback]
7313**   is never invoked.
7314**
7315** <dt>SQLITE_CHECKPOINT_FULL<dd>
7316**   This mode blocks (it invokes the
7317**   [sqlite3_busy_handler|busy-handler callback]) until there is no
7318**   database writer and all readers are reading from the most recent database
7319**   snapshot. It then checkpoints all frames in the log file and syncs the
7320**   database file. This call blocks database writers while it is running,
7321**   but not database readers.
7322**
7323** <dt>SQLITE_CHECKPOINT_RESTART<dd>
7324**   This mode works the same way as SQLITE_CHECKPOINT_FULL, except after
7325**   checkpointing the log file it blocks (calls the
7326**   [sqlite3_busy_handler|busy-handler callback])
7327**   until all readers are reading from the database file only. This ensures
7328**   that the next client to write to the database file restarts the log file
7329**   from the beginning. This call blocks database writers while it is running,
7330**   but not database readers.
7331** </dl>
7332**
7333** If pnLog is not NULL, then *pnLog is set to the total number of frames in
7334** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
7335** the total number of checkpointed frames (including any that were already
7336** checkpointed when this function is called). *pnLog and *pnCkpt may be
7337** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
7338** If no values are available because of an error, they are both set to -1
7339** before returning to communicate this to the caller.
7340**
7341** All calls obtain an exclusive "checkpoint" lock on the database file. If
7342** any other process is running a checkpoint operation at the same time, the
7343** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a
7344** busy-handler configured, it will not be invoked in this case.
7345**
7346** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive
7347** "writer" lock on the database file. If the writer lock cannot be obtained
7348** immediately, and a busy-handler is configured, it is invoked and the writer
7349** lock retried until either the busy-handler returns 0 or the lock is
7350** successfully obtained. The busy-handler is also invoked while waiting for
7351** database readers as described above. If the busy-handler returns 0 before
7352** the writer lock is obtained or while waiting for database readers, the
7353** checkpoint operation proceeds from that point in the same way as
7354** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
7355** without blocking any further. SQLITE_BUSY is returned in this case.
7356**
7357** If parameter zDb is NULL or points to a zero length string, then the
7358** specified operation is attempted on all WAL databases. In this case the
7359** values written to output parameters *pnLog and *pnCkpt are undefined. If
7360** an SQLITE_BUSY error is encountered when processing one or more of the
7361** attached WAL databases, the operation is still attempted on any remaining
7362** attached databases and SQLITE_BUSY is returned to the caller. If any other
7363** error occurs while processing an attached database, processing is abandoned
7364** and the error code returned to the caller immediately. If no error
7365** (SQLITE_BUSY or otherwise) is encountered while processing the attached
7366** databases, SQLITE_OK is returned.
7367**
7368** If database zDb is the name of an attached database that is not in WAL
7369** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
7370** zDb is not NULL (or a zero length string) and is not the name of any
7371** attached database, SQLITE_ERROR is returned to the caller.
7372*/
7373SQLITE_API int sqlite3_wal_checkpoint_v2(
7374  sqlite3 *db,                    /* Database handle */
7375  const char *zDb,                /* Name of attached database (or NULL) */
7376  int eMode,                      /* SQLITE_CHECKPOINT_* value */
7377  int *pnLog,                     /* OUT: Size of WAL log in frames */
7378  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
7379);
7380
7381/*
7382** CAPI3REF: Checkpoint operation parameters
7383**
7384** These constants can be used as the 3rd parameter to
7385** [sqlite3_wal_checkpoint_v2()].  See the [sqlite3_wal_checkpoint_v2()]
7386** documentation for additional information about the meaning and use of
7387** each of these values.
7388*/
7389#define SQLITE_CHECKPOINT_PASSIVE 0
7390#define SQLITE_CHECKPOINT_FULL    1
7391#define SQLITE_CHECKPOINT_RESTART 2
7392
7393/*
7394** CAPI3REF: Virtual Table Interface Configuration
7395**
7396** This function may be called by either the [xConnect] or [xCreate] method
7397** of a [virtual table] implementation to configure
7398** various facets of the virtual table interface.
7399**
7400** If this interface is invoked outside the context of an xConnect or
7401** xCreate virtual table method then the behavior is undefined.
7402**
7403** At present, there is only one option that may be configured using
7404** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].)  Further options
7405** may be added in the future.
7406*/
7407SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
7408
7409/*
7410** CAPI3REF: Virtual Table Configuration Options
7411**
7412** These macros define the various options to the
7413** [sqlite3_vtab_config()] interface that [virtual table] implementations
7414** can use to customize and optimize their behavior.
7415**
7416** <dl>
7417** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
7418** <dd>Calls of the form
7419** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
7420** where X is an integer.  If X is zero, then the [virtual table] whose
7421** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
7422** support constraints.  In this configuration (which is the default) if
7423** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
7424** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
7425** specified as part of the users SQL statement, regardless of the actual
7426** ON CONFLICT mode specified.
7427**
7428** If X is non-zero, then the virtual table implementation guarantees
7429** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
7430** any modifications to internal or persistent data structures have been made.
7431** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
7432** is able to roll back a statement or database transaction, and abandon
7433** or continue processing the current SQL statement as appropriate.
7434** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
7435** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
7436** had been ABORT.
7437**
7438** Virtual table implementations that are required to handle OR REPLACE
7439** must do so within the [xUpdate] method. If a call to the
7440** [sqlite3_vtab_on_conflict()] function indicates that the current ON
7441** CONFLICT policy is REPLACE, the virtual table implementation should
7442** silently replace the appropriate rows within the xUpdate callback and
7443** return SQLITE_OK. Or, if this is not possible, it may return
7444** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
7445** constraint handling.
7446** </dl>
7447*/
7448#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
7449
7450/*
7451** CAPI3REF: Determine The Virtual Table Conflict Policy
7452**
7453** This function may only be called from within a call to the [xUpdate] method
7454** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
7455** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
7456** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
7457** of the SQL statement that triggered the call to the [xUpdate] method of the
7458** [virtual table].
7459*/
7460SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
7461
7462/*
7463** CAPI3REF: Conflict resolution modes
7464** KEYWORDS: {conflict resolution mode}
7465**
7466** These constants are returned by [sqlite3_vtab_on_conflict()] to
7467** inform a [virtual table] implementation what the [ON CONFLICT] mode
7468** is for the SQL statement being evaluated.
7469**
7470** Note that the [SQLITE_IGNORE] constant is also used as a potential
7471** return value from the [sqlite3_set_authorizer()] callback and that
7472** [SQLITE_ABORT] is also a [result code].
7473*/
7474#define SQLITE_ROLLBACK 1
7475/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
7476#define SQLITE_FAIL     3
7477/* #define SQLITE_ABORT 4  // Also an error code */
7478#define SQLITE_REPLACE  5
7479
7480
7481
7482/*
7483** Undo the hack that converts floating point types to integer for
7484** builds on processors without floating point support.
7485*/
7486#ifdef SQLITE_OMIT_FLOATING_POINT
7487# undef double
7488#endif
7489
7490#if 0
7491}  /* End of the 'extern "C"' block */
7492#endif
7493#endif /* _SQLITE3_H_ */
7494
7495/*
7496** 2010 August 30
7497**
7498** The author disclaims copyright to this source code.  In place of
7499** a legal notice, here is a blessing:
7500**
7501**    May you do good and not evil.
7502**    May you find forgiveness for yourself and forgive others.
7503**    May you share freely, never taking more than you give.
7504**
7505*************************************************************************
7506*/
7507
7508#ifndef _SQLITE3RTREE_H_
7509#define _SQLITE3RTREE_H_
7510
7511
7512#if 0
7513extern "C" {
7514#endif
7515
7516typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
7517typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
7518
7519/* The double-precision datatype used by RTree depends on the
7520** SQLITE_RTREE_INT_ONLY compile-time option.
7521*/
7522#ifdef SQLITE_RTREE_INT_ONLY
7523  typedef sqlite3_int64 sqlite3_rtree_dbl;
7524#else
7525  typedef double sqlite3_rtree_dbl;
7526#endif
7527
7528/*
7529** Register a geometry callback named zGeom that can be used as part of an
7530** R-Tree geometry query as follows:
7531**
7532**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
7533*/
7534SQLITE_API int sqlite3_rtree_geometry_callback(
7535  sqlite3 *db,
7536  const char *zGeom,
7537  int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
7538  void *pContext
7539);
7540
7541
7542/*
7543** A pointer to a structure of the following type is passed as the first
7544** argument to callbacks registered using rtree_geometry_callback().
7545*/
7546struct sqlite3_rtree_geometry {
7547  void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
7548  int nParam;                     /* Size of array aParam[] */
7549  sqlite3_rtree_dbl *aParam;      /* Parameters passed to SQL geom function */
7550  void *pUser;                    /* Callback implementation user data */
7551  void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
7552};
7553
7554/*
7555** Register a 2nd-generation geometry callback named zScore that can be
7556** used as part of an R-Tree geometry query as follows:
7557**
7558**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
7559*/
7560SQLITE_API int sqlite3_rtree_query_callback(
7561  sqlite3 *db,
7562  const char *zQueryFunc,
7563  int (*xQueryFunc)(sqlite3_rtree_query_info*),
7564  void *pContext,
7565  void (*xDestructor)(void*)
7566);
7567
7568
7569/*
7570** A pointer to a structure of the following type is passed as the
7571** argument to scored geometry callback registered using
7572** sqlite3_rtree_query_callback().
7573**
7574** Note that the first 5 fields of this structure are identical to
7575** sqlite3_rtree_geometry.  This structure is a subclass of
7576** sqlite3_rtree_geometry.
7577*/
7578struct sqlite3_rtree_query_info {
7579  void *pContext;                   /* pContext from when function registered */
7580  int nParam;                       /* Number of function parameters */
7581  sqlite3_rtree_dbl *aParam;        /* value of function parameters */
7582  void *pUser;                      /* callback can use this, if desired */
7583  void (*xDelUser)(void*);          /* function to free pUser */
7584  sqlite3_rtree_dbl *aCoord;        /* Coordinates of node or entry to check */
7585  unsigned int *anQueue;            /* Number of pending entries in the queue */
7586  int nCoord;                       /* Number of coordinates */
7587  int iLevel;                       /* Level of current node or entry */
7588  int mxLevel;                      /* The largest iLevel value in the tree */
7589  sqlite3_int64 iRowid;             /* Rowid for current entry */
7590  sqlite3_rtree_dbl rParentScore;   /* Score of parent node */
7591  int eParentWithin;                /* Visibility of parent node */
7592  int eWithin;                      /* OUT: Visiblity */
7593  sqlite3_rtree_dbl rScore;         /* OUT: Write the score here */
7594};
7595
7596/*
7597** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
7598*/
7599#define NOT_WITHIN       0   /* Object completely outside of query region */
7600#define PARTLY_WITHIN    1   /* Object partially overlaps query region */
7601#define FULLY_WITHIN     2   /* Object fully contained within query region */
7602
7603
7604#if 0
7605}  /* end of the 'extern "C"' block */
7606#endif
7607
7608#endif  /* ifndef _SQLITE3RTREE_H_ */
7609
7610