xref: /sqlite-3.40.0/src/sqlite.h.in (revision b565bee6)
1/*
2** 2001-09-15
3**
4** The author disclaims copyright to this source code.  In place of
5** a legal notice, here is a blessing:
6**
7**    May you do good and not evil.
8**    May you find forgiveness for yourself and forgive others.
9**    May you share freely, never taking more than you give.
10**
11*************************************************************************
12** This header file defines the interface that the SQLite library
13** presents to client programs.  If a C-function, structure, datatype,
14** or constant definition does not appear in this file, then it is
15** not a published API of SQLite, is subject to change without
16** notice, and should not be referenced by programs that use SQLite.
17**
18** Some of the definitions that are in this file are marked as
19** "experimental".  Experimental interfaces are normally new
20** features recently added to SQLite.  We do not anticipate changes
21** to experimental interfaces but reserve the right to make minor changes
22** if experience from use "in the wild" suggest such changes are prudent.
23**
24** The official C-language API documentation for SQLite is derived
25** from comments in this file.  This file is the authoritative source
26** on how SQLite interfaces are supposed to operate.
27**
28** The name of this file under configuration management is "sqlite.h.in".
29** The makefile makes some minor changes to this file (such as inserting
30** the version number) and changes its name to "sqlite3.h" as
31** part of the build process.
32*/
33#ifndef SQLITE3_H
34#define SQLITE3_H
35#include <stdarg.h>     /* Needed for the definition of va_list */
36
37/*
38** Make sure we can call this stuff from C++.
39*/
40#ifdef __cplusplus
41extern "C" {
42#endif
43
44
45/*
46** Facilitate override of interface linkage and calling conventions.
47** Be aware that these macros may not be used within this particular
48** translation of the amalgamation and its associated header file.
49**
50** The SQLITE_EXTERN and SQLITE_API macros are used to instruct the
51** compiler that the target identifier should have external linkage.
52**
53** The SQLITE_CDECL macro is used to set the calling convention for
54** public functions that accept a variable number of arguments.
55**
56** The SQLITE_APICALL macro is used to set the calling convention for
57** public functions that accept a fixed number of arguments.
58**
59** The SQLITE_STDCALL macro is no longer used and is now deprecated.
60**
61** The SQLITE_CALLBACK macro is used to set the calling convention for
62** function pointers.
63**
64** The SQLITE_SYSAPI macro is used to set the calling convention for
65** functions provided by the operating system.
66**
67** Currently, the SQLITE_CDECL, SQLITE_APICALL, SQLITE_CALLBACK, and
68** SQLITE_SYSAPI macros are used only when building for environments
69** that require non-default calling conventions.
70*/
71#ifndef SQLITE_EXTERN
72# define SQLITE_EXTERN extern
73#endif
74#ifndef SQLITE_API
75# define SQLITE_API
76#endif
77#ifndef SQLITE_CDECL
78# define SQLITE_CDECL
79#endif
80#ifndef SQLITE_APICALL
81# define SQLITE_APICALL
82#endif
83#ifndef SQLITE_STDCALL
84# define SQLITE_STDCALL SQLITE_APICALL
85#endif
86#ifndef SQLITE_CALLBACK
87# define SQLITE_CALLBACK
88#endif
89#ifndef SQLITE_SYSAPI
90# define SQLITE_SYSAPI
91#endif
92
93/*
94** These no-op macros are used in front of interfaces to mark those
95** interfaces as either deprecated or experimental.  New applications
96** should not use deprecated interfaces - they are supported for backwards
97** compatibility only.  Application writers should be aware that
98** experimental interfaces are subject to change in point releases.
99**
100** These macros used to resolve to various kinds of compiler magic that
101** would generate warning messages when they were used.  But that
102** compiler magic ended up generating such a flurry of bug reports
103** that we have taken it all out and gone back to using simple
104** noop macros.
105*/
106#define SQLITE_DEPRECATED
107#define SQLITE_EXPERIMENTAL
108
109/*
110** Ensure these symbols were not defined by some previous header file.
111*/
112#ifdef SQLITE_VERSION
113# undef SQLITE_VERSION
114#endif
115#ifdef SQLITE_VERSION_NUMBER
116# undef SQLITE_VERSION_NUMBER
117#endif
118
119/*
120** CAPI3REF: Compile-Time Library Version Numbers
121**
122** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
123** evaluates to a string literal that is the SQLite version in the
124** format "X.Y.Z" where X is the major version number (always 3 for
125** SQLite3) and Y is the minor version number and Z is the release number.)^
126** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
127** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
128** numbers used in [SQLITE_VERSION].)^
129** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
130** be larger than the release from which it is derived.  Either Y will
131** be held constant and Z will be incremented or else Y will be incremented
132** and Z will be reset to zero.
133**
134** Since [version 3.6.18] ([dateof:3.6.18]),
135** SQLite source code has been stored in the
136** <a href="http://www.fossil-scm.org/">Fossil configuration management
137** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
138** a string which identifies a particular check-in of SQLite
139** within its configuration management system.  ^The SQLITE_SOURCE_ID
140** string contains the date and time of the check-in (UTC) and a SHA1
141** or SHA3-256 hash of the entire source tree.  If the source code has
142** been edited in any way since it was last checked in, then the last
143** four hexadecimal digits of the hash may be modified.
144**
145** See also: [sqlite3_libversion()],
146** [sqlite3_libversion_number()], [sqlite3_sourceid()],
147** [sqlite_version()] and [sqlite_source_id()].
148*/
149#define SQLITE_VERSION        "--VERS--"
150#define SQLITE_VERSION_NUMBER --VERSION-NUMBER--
151#define SQLITE_SOURCE_ID      "--SOURCE-ID--"
152
153/*
154** CAPI3REF: Run-Time Library Version Numbers
155** KEYWORDS: sqlite3_version sqlite3_sourceid
156**
157** These interfaces provide the same information as the [SQLITE_VERSION],
158** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
159** but are associated with the library instead of the header file.  ^(Cautious
160** programmers might include assert() statements in their application to
161** verify that values returned by these interfaces match the macros in
162** the header, and thus ensure that the application is
163** compiled with matching library and header files.
164**
165** <blockquote><pre>
166** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
167** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
168** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
169** </pre></blockquote>)^
170**
171** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
172** macro.  ^The sqlite3_libversion() function returns a pointer to the
173** to the sqlite3_version[] string constant.  The sqlite3_libversion()
174** function is provided for use in DLLs since DLL users usually do not have
175** direct access to string constants within the DLL.  ^The
176** sqlite3_libversion_number() function returns an integer equal to
177** [SQLITE_VERSION_NUMBER].  ^(The sqlite3_sourceid() function returns
178** a pointer to a string constant whose value is the same as the
179** [SQLITE_SOURCE_ID] C preprocessor macro.  Except if SQLite is built
180** using an edited copy of [the amalgamation], then the last four characters
181** of the hash might be different from [SQLITE_SOURCE_ID].)^
182**
183** See also: [sqlite_version()] and [sqlite_source_id()].
184*/
185SQLITE_EXTERN const char sqlite3_version[];
186const char *sqlite3_libversion(void);
187const char *sqlite3_sourceid(void);
188int sqlite3_libversion_number(void);
189
190/*
191** CAPI3REF: Run-Time Library Compilation Options Diagnostics
192**
193** ^The sqlite3_compileoption_used() function returns 0 or 1
194** indicating whether the specified option was defined at
195** compile time.  ^The SQLITE_ prefix may be omitted from the
196** option name passed to sqlite3_compileoption_used().
197**
198** ^The sqlite3_compileoption_get() function allows iterating
199** over the list of options that were defined at compile time by
200** returning the N-th compile time option string.  ^If N is out of range,
201** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_
202** prefix is omitted from any strings returned by
203** sqlite3_compileoption_get().
204**
205** ^Support for the diagnostic functions sqlite3_compileoption_used()
206** and sqlite3_compileoption_get() may be omitted by specifying the
207** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
208**
209** See also: SQL functions [sqlite_compileoption_used()] and
210** [sqlite_compileoption_get()] and the [compile_options pragma].
211*/
212#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
213int sqlite3_compileoption_used(const char *zOptName);
214const char *sqlite3_compileoption_get(int N);
215#else
216# define sqlite3_compileoption_used(X) 0
217# define sqlite3_compileoption_get(X)  ((void*)0)
218#endif
219
220/*
221** CAPI3REF: Test To See If The Library Is Threadsafe
222**
223** ^The sqlite3_threadsafe() function returns zero if and only if
224** SQLite was compiled with mutexing code omitted due to the
225** [SQLITE_THREADSAFE] compile-time option being set to 0.
226**
227** SQLite can be compiled with or without mutexes.  When
228** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
229** are enabled and SQLite is threadsafe.  When the
230** [SQLITE_THREADSAFE] macro is 0,
231** the mutexes are omitted.  Without the mutexes, it is not safe
232** to use SQLite concurrently from more than one thread.
233**
234** Enabling mutexes incurs a measurable performance penalty.
235** So if speed is of utmost importance, it makes sense to disable
236** the mutexes.  But for maximum safety, mutexes should be enabled.
237** ^The default behavior is for mutexes to be enabled.
238**
239** This interface can be used by an application to make sure that the
240** version of SQLite that it is linking against was compiled with
241** the desired setting of the [SQLITE_THREADSAFE] macro.
242**
243** This interface only reports on the compile-time mutex setting
244** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
245** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
246** can be fully or partially disabled using a call to [sqlite3_config()]
247** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
248** or [SQLITE_CONFIG_SERIALIZED].  ^(The return value of the
249** sqlite3_threadsafe() function shows only the compile-time setting of
250** thread safety, not any run-time changes to that setting made by
251** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
252** is unchanged by calls to sqlite3_config().)^
253**
254** See the [threading mode] documentation for additional information.
255*/
256int sqlite3_threadsafe(void);
257
258/*
259** CAPI3REF: Database Connection Handle
260** KEYWORDS: {database connection} {database connections}
261**
262** Each open SQLite database is represented by a pointer to an instance of
263** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
264** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
265** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
266** and [sqlite3_close_v2()] are its destructors.  There are many other
267** interfaces (such as
268** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
269** [sqlite3_busy_timeout()] to name but three) that are methods on an
270** sqlite3 object.
271*/
272typedef struct sqlite3 sqlite3;
273
274/*
275** CAPI3REF: 64-Bit Integer Types
276** KEYWORDS: sqlite_int64 sqlite_uint64
277**
278** Because there is no cross-platform way to specify 64-bit integer types
279** SQLite includes typedefs for 64-bit signed and unsigned integers.
280**
281** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
282** The sqlite_int64 and sqlite_uint64 types are supported for backwards
283** compatibility only.
284**
285** ^The sqlite3_int64 and sqlite_int64 types can store integer values
286** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
287** sqlite3_uint64 and sqlite_uint64 types can store integer values
288** between 0 and +18446744073709551615 inclusive.
289*/
290#ifdef SQLITE_INT64_TYPE
291  typedef SQLITE_INT64_TYPE sqlite_int64;
292# ifdef SQLITE_UINT64_TYPE
293    typedef SQLITE_UINT64_TYPE sqlite_uint64;
294# else
295    typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
296# endif
297#elif defined(_MSC_VER) || defined(__BORLANDC__)
298  typedef __int64 sqlite_int64;
299  typedef unsigned __int64 sqlite_uint64;
300#else
301  typedef long long int sqlite_int64;
302  typedef unsigned long long int sqlite_uint64;
303#endif
304typedef sqlite_int64 sqlite3_int64;
305typedef sqlite_uint64 sqlite3_uint64;
306
307/*
308** If compiling for a processor that lacks floating point support,
309** substitute integer for floating-point.
310*/
311#ifdef SQLITE_OMIT_FLOATING_POINT
312# define double sqlite3_int64
313#endif
314
315/*
316** CAPI3REF: Closing A Database Connection
317** DESTRUCTOR: sqlite3
318**
319** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
320** for the [sqlite3] object.
321** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
322** the [sqlite3] object is successfully destroyed and all associated
323** resources are deallocated.
324**
325** Ideally, applications should [sqlite3_finalize | finalize] all
326** [prepared statements], [sqlite3_blob_close | close] all [BLOB handles], and
327** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
328** with the [sqlite3] object prior to attempting to close the object.
329** ^If the database connection is associated with unfinalized prepared
330** statements, BLOB handlers, and/or unfinished sqlite3_backup objects then
331** sqlite3_close() will leave the database connection open and return
332** [SQLITE_BUSY]. ^If sqlite3_close_v2() is called with unfinalized prepared
333** statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups,
334** it returns [SQLITE_OK] regardless, but instead of deallocating the database
335** connection immediately, it marks the database connection as an unusable
336** "zombie" and makes arrangements to automatically deallocate the database
337** connection after all prepared statements are finalized, all BLOB handles
338** are closed, and all backups have finished. The sqlite3_close_v2() interface
339** is intended for use with host languages that are garbage collected, and
340** where the order in which destructors are called is arbitrary.
341**
342** ^If an [sqlite3] object is destroyed while a transaction is open,
343** the transaction is automatically rolled back.
344**
345** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
346** must be either a NULL
347** pointer or an [sqlite3] object pointer obtained
348** from [sqlite3_open()], [sqlite3_open16()], or
349** [sqlite3_open_v2()], and not previously closed.
350** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
351** argument is a harmless no-op.
352*/
353int sqlite3_close(sqlite3*);
354int sqlite3_close_v2(sqlite3*);
355
356/*
357** The type for a callback function.
358** This is legacy and deprecated.  It is included for historical
359** compatibility and is not documented.
360*/
361typedef int (*sqlite3_callback)(void*,int,char**, char**);
362
363/*
364** CAPI3REF: One-Step Query Execution Interface
365** METHOD: sqlite3
366**
367** The sqlite3_exec() interface is a convenience wrapper around
368** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
369** that allows an application to run multiple statements of SQL
370** without having to use a lot of C code.
371**
372** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
373** semicolon-separate SQL statements passed into its 2nd argument,
374** in the context of the [database connection] passed in as its 1st
375** argument.  ^If the callback function of the 3rd argument to
376** sqlite3_exec() is not NULL, then it is invoked for each result row
377** coming out of the evaluated SQL statements.  ^The 4th argument to
378** sqlite3_exec() is relayed through to the 1st argument of each
379** callback invocation.  ^If the callback pointer to sqlite3_exec()
380** is NULL, then no callback is ever invoked and result rows are
381** ignored.
382**
383** ^If an error occurs while evaluating the SQL statements passed into
384** sqlite3_exec(), then execution of the current statement stops and
385** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
386** is not NULL then any error message is written into memory obtained
387** from [sqlite3_malloc()] and passed back through the 5th parameter.
388** To avoid memory leaks, the application should invoke [sqlite3_free()]
389** on error message strings returned through the 5th parameter of
390** sqlite3_exec() after the error message string is no longer needed.
391** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
392** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
393** NULL before returning.
394**
395** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
396** routine returns SQLITE_ABORT without invoking the callback again and
397** without running any subsequent SQL statements.
398**
399** ^The 2nd argument to the sqlite3_exec() callback function is the
400** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
401** callback is an array of pointers to strings obtained as if from
402** [sqlite3_column_text()], one for each column.  ^If an element of a
403** result row is NULL then the corresponding string pointer for the
404** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
405** sqlite3_exec() callback is an array of pointers to strings where each
406** entry represents the name of corresponding result column as obtained
407** from [sqlite3_column_name()].
408**
409** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
410** to an empty string, or a pointer that contains only whitespace and/or
411** SQL comments, then no SQL statements are evaluated and the database
412** is not changed.
413**
414** Restrictions:
415**
416** <ul>
417** <li> The application must ensure that the 1st parameter to sqlite3_exec()
418**      is a valid and open [database connection].
419** <li> The application must not close the [database connection] specified by
420**      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
421** <li> The application must not modify the SQL statement text passed into
422**      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
423** </ul>
424*/
425int sqlite3_exec(
426  sqlite3*,                                  /* An open database */
427  const char *sql,                           /* SQL to be evaluated */
428  int (*callback)(void*,int,char**,char**),  /* Callback function */
429  void *,                                    /* 1st argument to callback */
430  char **errmsg                              /* Error msg written here */
431);
432
433/*
434** CAPI3REF: Result Codes
435** KEYWORDS: {result code definitions}
436**
437** Many SQLite functions return an integer result code from the set shown
438** here in order to indicate success or failure.
439**
440** New error codes may be added in future versions of SQLite.
441**
442** See also: [extended result code definitions]
443*/
444#define SQLITE_OK           0   /* Successful result */
445/* beginning-of-error-codes */
446#define SQLITE_ERROR        1   /* Generic error */
447#define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
448#define SQLITE_PERM         3   /* Access permission denied */
449#define SQLITE_ABORT        4   /* Callback routine requested an abort */
450#define SQLITE_BUSY         5   /* The database file is locked */
451#define SQLITE_LOCKED       6   /* A table in the database is locked */
452#define SQLITE_NOMEM        7   /* A malloc() failed */
453#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
454#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
455#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
456#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
457#define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
458#define SQLITE_FULL        13   /* Insertion failed because database is full */
459#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
460#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
461#define SQLITE_EMPTY       16   /* Internal use only */
462#define SQLITE_SCHEMA      17   /* The database schema changed */
463#define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
464#define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
465#define SQLITE_MISMATCH    20   /* Data type mismatch */
466#define SQLITE_MISUSE      21   /* Library used incorrectly */
467#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
468#define SQLITE_AUTH        23   /* Authorization denied */
469#define SQLITE_FORMAT      24   /* Not used */
470#define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
471#define SQLITE_NOTADB      26   /* File opened that is not a database file */
472#define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
473#define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
474#define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
475#define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
476/* end-of-error-codes */
477
478/*
479** CAPI3REF: Extended Result Codes
480** KEYWORDS: {extended result code definitions}
481**
482** In its default configuration, SQLite API routines return one of 30 integer
483** [result codes].  However, experience has shown that many of
484** these result codes are too coarse-grained.  They do not provide as
485** much information about problems as programmers might like.  In an effort to
486** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
487** and later) include
488** support for additional result codes that provide more detailed information
489** about errors. These [extended result codes] are enabled or disabled
490** on a per database connection basis using the
491** [sqlite3_extended_result_codes()] API.  Or, the extended code for
492** the most recent error can be obtained using
493** [sqlite3_extended_errcode()].
494*/
495#define SQLITE_ERROR_MISSING_COLLSEQ   (SQLITE_ERROR | (1<<8))
496#define SQLITE_ERROR_RETRY             (SQLITE_ERROR | (2<<8))
497#define SQLITE_ERROR_SNAPSHOT          (SQLITE_ERROR | (3<<8))
498#define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
499#define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
500#define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
501#define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
502#define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
503#define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
504#define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
505#define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
506#define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
507#define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
508#define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
509#define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
510#define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
511#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
512#define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
513#define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
514#define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
515#define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
516#define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
517#define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
518#define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
519#define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
520#define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
521#define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
522#define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
523#define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
524#define SQLITE_IOERR_VNODE             (SQLITE_IOERR | (27<<8))
525#define SQLITE_IOERR_AUTH              (SQLITE_IOERR | (28<<8))
526#define SQLITE_IOERR_BEGIN_ATOMIC      (SQLITE_IOERR | (29<<8))
527#define SQLITE_IOERR_COMMIT_ATOMIC     (SQLITE_IOERR | (30<<8))
528#define SQLITE_IOERR_ROLLBACK_ATOMIC   (SQLITE_IOERR | (31<<8))
529#define SQLITE_IOERR_DATA              (SQLITE_IOERR | (32<<8))
530#define SQLITE_IOERR_CORRUPTFS         (SQLITE_IOERR | (33<<8))
531#define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
532#define SQLITE_LOCKED_VTAB             (SQLITE_LOCKED |  (2<<8))
533#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
534#define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
535#define SQLITE_BUSY_TIMEOUT            (SQLITE_BUSY   |  (3<<8))
536#define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
537#define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
538#define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
539#define SQLITE_CANTOPEN_CONVPATH       (SQLITE_CANTOPEN | (4<<8))
540#define SQLITE_CANTOPEN_DIRTYWAL       (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
541#define SQLITE_CANTOPEN_SYMLINK        (SQLITE_CANTOPEN | (6<<8))
542#define SQLITE_CANTOPEN_EXISTS         (SQLITE_CANTOPEN | (7<<8))
543#define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
544#define SQLITE_CORRUPT_SEQUENCE        (SQLITE_CORRUPT | (2<<8))
545#define SQLITE_CORRUPT_INDEX           (SQLITE_CORRUPT | (3<<8))
546#define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
547#define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
548#define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
549#define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
550#define SQLITE_READONLY_CANTINIT       (SQLITE_READONLY | (5<<8))
551#define SQLITE_READONLY_DIRECTORY      (SQLITE_READONLY | (6<<8))
552#define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
553#define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
554#define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
555#define SQLITE_CONSTRAINT_FOREIGNKEY   (SQLITE_CONSTRAINT | (3<<8))
556#define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
557#define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
558#define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
559#define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
560#define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
561#define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
562#define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
563#define SQLITE_CONSTRAINT_PINNED       (SQLITE_CONSTRAINT |(11<<8))
564#define SQLITE_CONSTRAINT_DATATYPE     (SQLITE_CONSTRAINT |(12<<8))
565#define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
566#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
567#define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
568#define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
569#define SQLITE_OK_LOAD_PERMANENTLY     (SQLITE_OK | (1<<8))
570#define SQLITE_OK_SYMLINK              (SQLITE_OK | (2<<8))
571
572/*
573** CAPI3REF: Flags For File Open Operations
574**
575** These bit values are intended for use in the
576** 3rd parameter to the [sqlite3_open_v2()] interface and
577** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
578*/
579#define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
580#define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
581#define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
582#define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
583#define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
584#define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
585#define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
586#define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
587#define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
588#define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
589#define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
590#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
591#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
592#define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
593#define SQLITE_OPEN_SUPER_JOURNAL    0x00004000  /* VFS only */
594#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
595#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
596#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
597#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
598#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
599#define SQLITE_OPEN_NOFOLLOW         0x01000000  /* Ok for sqlite3_open_v2() */
600
601/* Reserved:                         0x00F00000 */
602/* Legacy compatibility: */
603#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
604
605
606/*
607** CAPI3REF: Device Characteristics
608**
609** The xDeviceCharacteristics method of the [sqlite3_io_methods]
610** object returns an integer which is a vector of these
611** bit values expressing I/O characteristics of the mass storage
612** device that holds the file that the [sqlite3_io_methods]
613** refers to.
614**
615** The SQLITE_IOCAP_ATOMIC property means that all writes of
616** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
617** mean that writes of blocks that are nnn bytes in size and
618** are aligned to an address which is an integer multiple of
619** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
620** that when data is appended to a file, the data is appended
621** first then the size of the file is extended, never the other
622** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
623** information is written to disk in the same order as calls
624** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
625** after reboot following a crash or power loss, the only bytes in a
626** file that were written at the application level might have changed
627** and that adjacent bytes, even bytes within the same sector are
628** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
629** flag indicates that a file cannot be deleted when open.  The
630** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
631** read-only media and cannot be changed even by processes with
632** elevated privileges.
633**
634** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
635** filesystem supports doing multiple write operations atomically when those
636** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
637** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
638*/
639#define SQLITE_IOCAP_ATOMIC                 0x00000001
640#define SQLITE_IOCAP_ATOMIC512              0x00000002
641#define SQLITE_IOCAP_ATOMIC1K               0x00000004
642#define SQLITE_IOCAP_ATOMIC2K               0x00000008
643#define SQLITE_IOCAP_ATOMIC4K               0x00000010
644#define SQLITE_IOCAP_ATOMIC8K               0x00000020
645#define SQLITE_IOCAP_ATOMIC16K              0x00000040
646#define SQLITE_IOCAP_ATOMIC32K              0x00000080
647#define SQLITE_IOCAP_ATOMIC64K              0x00000100
648#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
649#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
650#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
651#define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
652#define SQLITE_IOCAP_IMMUTABLE              0x00002000
653#define SQLITE_IOCAP_BATCH_ATOMIC           0x00004000
654
655/*
656** CAPI3REF: File Locking Levels
657**
658** SQLite uses one of these integer values as the second
659** argument to calls it makes to the xLock() and xUnlock() methods
660** of an [sqlite3_io_methods] object.
661*/
662#define SQLITE_LOCK_NONE          0
663#define SQLITE_LOCK_SHARED        1
664#define SQLITE_LOCK_RESERVED      2
665#define SQLITE_LOCK_PENDING       3
666#define SQLITE_LOCK_EXCLUSIVE     4
667
668/*
669** CAPI3REF: Synchronization Type Flags
670**
671** When SQLite invokes the xSync() method of an
672** [sqlite3_io_methods] object it uses a combination of
673** these integer values as the second argument.
674**
675** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
676** sync operation only needs to flush data to mass storage.  Inode
677** information need not be flushed. If the lower four bits of the flag
678** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
679** If the lower four bits equal SQLITE_SYNC_FULL, that means
680** to use Mac OS X style fullsync instead of fsync().
681**
682** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
683** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
684** settings.  The [synchronous pragma] determines when calls to the
685** xSync VFS method occur and applies uniformly across all platforms.
686** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
687** energetic or rigorous or forceful the sync operations are and
688** only make a difference on Mac OSX for the default SQLite code.
689** (Third-party VFS implementations might also make the distinction
690** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
691** operating systems natively supported by SQLite, only Mac OSX
692** cares about the difference.)
693*/
694#define SQLITE_SYNC_NORMAL        0x00002
695#define SQLITE_SYNC_FULL          0x00003
696#define SQLITE_SYNC_DATAONLY      0x00010
697
698/*
699** CAPI3REF: OS Interface Open File Handle
700**
701** An [sqlite3_file] object represents an open file in the
702** [sqlite3_vfs | OS interface layer].  Individual OS interface
703** implementations will
704** want to subclass this object by appending additional fields
705** for their own use.  The pMethods entry is a pointer to an
706** [sqlite3_io_methods] object that defines methods for performing
707** I/O operations on the open file.
708*/
709typedef struct sqlite3_file sqlite3_file;
710struct sqlite3_file {
711  const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
712};
713
714/*
715** CAPI3REF: OS Interface File Virtual Methods Object
716**
717** Every file opened by the [sqlite3_vfs.xOpen] method populates an
718** [sqlite3_file] object (or, more commonly, a subclass of the
719** [sqlite3_file] object) with a pointer to an instance of this object.
720** This object defines the methods used to perform various operations
721** against the open file represented by the [sqlite3_file] object.
722**
723** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
724** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
725** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
726** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
727** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
728** to NULL.
729**
730** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
731** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
732** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
733** flag may be ORed in to indicate that only the data of the file
734** and not its inode needs to be synced.
735**
736** The integer values to xLock() and xUnlock() are one of
737** <ul>
738** <li> [SQLITE_LOCK_NONE],
739** <li> [SQLITE_LOCK_SHARED],
740** <li> [SQLITE_LOCK_RESERVED],
741** <li> [SQLITE_LOCK_PENDING], or
742** <li> [SQLITE_LOCK_EXCLUSIVE].
743** </ul>
744** xLock() increases the lock. xUnlock() decreases the lock.
745** The xCheckReservedLock() method checks whether any database connection,
746** either in this process or in some other process, is holding a RESERVED,
747** PENDING, or EXCLUSIVE lock on the file.  It returns true
748** if such a lock exists and false otherwise.
749**
750** The xFileControl() method is a generic interface that allows custom
751** VFS implementations to directly control an open file using the
752** [sqlite3_file_control()] interface.  The second "op" argument is an
753** integer opcode.  The third argument is a generic pointer intended to
754** point to a structure that may contain arguments or space in which to
755** write return values.  Potential uses for xFileControl() might be
756** functions to enable blocking locks with timeouts, to change the
757** locking strategy (for example to use dot-file locks), to inquire
758** about the status of a lock, or to break stale locks.  The SQLite
759** core reserves all opcodes less than 100 for its own use.
760** A [file control opcodes | list of opcodes] less than 100 is available.
761** Applications that define a custom xFileControl method should use opcodes
762** greater than 100 to avoid conflicts.  VFS implementations should
763** return [SQLITE_NOTFOUND] for file control opcodes that they do not
764** recognize.
765**
766** The xSectorSize() method returns the sector size of the
767** device that underlies the file.  The sector size is the
768** minimum write that can be performed without disturbing
769** other bytes in the file.  The xDeviceCharacteristics()
770** method returns a bit vector describing behaviors of the
771** underlying device:
772**
773** <ul>
774** <li> [SQLITE_IOCAP_ATOMIC]
775** <li> [SQLITE_IOCAP_ATOMIC512]
776** <li> [SQLITE_IOCAP_ATOMIC1K]
777** <li> [SQLITE_IOCAP_ATOMIC2K]
778** <li> [SQLITE_IOCAP_ATOMIC4K]
779** <li> [SQLITE_IOCAP_ATOMIC8K]
780** <li> [SQLITE_IOCAP_ATOMIC16K]
781** <li> [SQLITE_IOCAP_ATOMIC32K]
782** <li> [SQLITE_IOCAP_ATOMIC64K]
783** <li> [SQLITE_IOCAP_SAFE_APPEND]
784** <li> [SQLITE_IOCAP_SEQUENTIAL]
785** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
786** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
787** <li> [SQLITE_IOCAP_IMMUTABLE]
788** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
789** </ul>
790**
791** The SQLITE_IOCAP_ATOMIC property means that all writes of
792** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
793** mean that writes of blocks that are nnn bytes in size and
794** are aligned to an address which is an integer multiple of
795** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
796** that when data is appended to a file, the data is appended
797** first then the size of the file is extended, never the other
798** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
799** information is written to disk in the same order as calls
800** to xWrite().
801**
802** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
803** in the unread portions of the buffer with zeros.  A VFS that
804** fails to zero-fill short reads might seem to work.  However,
805** failure to zero-fill short reads will eventually lead to
806** database corruption.
807*/
808typedef struct sqlite3_io_methods sqlite3_io_methods;
809struct sqlite3_io_methods {
810  int iVersion;
811  int (*xClose)(sqlite3_file*);
812  int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
813  int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
814  int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
815  int (*xSync)(sqlite3_file*, int flags);
816  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
817  int (*xLock)(sqlite3_file*, int);
818  int (*xUnlock)(sqlite3_file*, int);
819  int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
820  int (*xFileControl)(sqlite3_file*, int op, void *pArg);
821  int (*xSectorSize)(sqlite3_file*);
822  int (*xDeviceCharacteristics)(sqlite3_file*);
823  /* Methods above are valid for version 1 */
824  int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
825  int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
826  void (*xShmBarrier)(sqlite3_file*);
827  int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
828  /* Methods above are valid for version 2 */
829  int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
830  int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
831  /* Methods above are valid for version 3 */
832  /* Additional methods may be added in future releases */
833};
834
835/*
836** CAPI3REF: Standard File Control Opcodes
837** KEYWORDS: {file control opcodes} {file control opcode}
838**
839** These integer constants are opcodes for the xFileControl method
840** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
841** interface.
842**
843** <ul>
844** <li>[[SQLITE_FCNTL_LOCKSTATE]]
845** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
846** opcode causes the xFileControl method to write the current state of
847** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
848** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
849** into an integer that the pArg argument points to. This capability
850** is used during testing and is only available when the SQLITE_TEST
851** compile-time option is used.
852**
853** <li>[[SQLITE_FCNTL_SIZE_HINT]]
854** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
855** layer a hint of how large the database file will grow to be during the
856** current transaction.  This hint is not guaranteed to be accurate but it
857** is often close.  The underlying VFS might choose to preallocate database
858** file space based on this hint in order to help writes to the database
859** file run faster.
860**
861** <li>[[SQLITE_FCNTL_SIZE_LIMIT]]
862** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that
863** implements [sqlite3_deserialize()] to set an upper bound on the size
864** of the in-memory database.  The argument is a pointer to a [sqlite3_int64].
865** If the integer pointed to is negative, then it is filled in with the
866** current limit.  Otherwise the limit is set to the larger of the value
867** of the integer pointed to and the current database size.  The integer
868** pointed to is set to the new limit.
869**
870** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
871** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
872** extends and truncates the database file in chunks of a size specified
873** by the user. The fourth argument to [sqlite3_file_control()] should
874** point to an integer (type int) containing the new chunk-size to use
875** for the nominated database. Allocating database file space in large
876** chunks (say 1MB at a time), may reduce file-system fragmentation and
877** improve performance on some systems.
878**
879** <li>[[SQLITE_FCNTL_FILE_POINTER]]
880** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
881** to the [sqlite3_file] object associated with a particular database
882** connection.  See also [SQLITE_FCNTL_JOURNAL_POINTER].
883**
884** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
885** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
886** to the [sqlite3_file] object associated with the journal file (either
887** the [rollback journal] or the [write-ahead log]) for a particular database
888** connection.  See also [SQLITE_FCNTL_FILE_POINTER].
889**
890** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
891** No longer in use.
892**
893** <li>[[SQLITE_FCNTL_SYNC]]
894** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
895** sent to the VFS immediately before the xSync method is invoked on a
896** database file descriptor. Or, if the xSync method is not invoked
897** because the user has configured SQLite with
898** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
899** of the xSync method. In most cases, the pointer argument passed with
900** this file-control is NULL. However, if the database file is being synced
901** as part of a multi-database commit, the argument points to a nul-terminated
902** string containing the transactions super-journal file name. VFSes that
903** do not need this signal should silently ignore this opcode. Applications
904** should not call [sqlite3_file_control()] with this opcode as doing so may
905** disrupt the operation of the specialized VFSes that do require it.
906**
907** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
908** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
909** and sent to the VFS after a transaction has been committed immediately
910** but before the database is unlocked. VFSes that do not need this signal
911** should silently ignore this opcode. Applications should not call
912** [sqlite3_file_control()] with this opcode as doing so may disrupt the
913** operation of the specialized VFSes that do require it.
914**
915** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
916** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
917** retry counts and intervals for certain disk I/O operations for the
918** windows [VFS] in order to provide robustness in the presence of
919** anti-virus programs.  By default, the windows VFS will retry file read,
920** file write, and file delete operations up to 10 times, with a delay
921** of 25 milliseconds before the first retry and with the delay increasing
922** by an additional 25 milliseconds with each subsequent retry.  This
923** opcode allows these two values (10 retries and 25 milliseconds of delay)
924** to be adjusted.  The values are changed for all database connections
925** within the same process.  The argument is a pointer to an array of two
926** integers where the first integer is the new retry count and the second
927** integer is the delay.  If either integer is negative, then the setting
928** is not changed but instead the prior value of that setting is written
929** into the array entry, allowing the current retry settings to be
930** interrogated.  The zDbName parameter is ignored.
931**
932** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
933** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
934** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
935** write ahead log ([WAL file]) and shared memory
936** files used for transaction control
937** are automatically deleted when the latest connection to the database
938** closes.  Setting persistent WAL mode causes those files to persist after
939** close.  Persisting the files is useful when other processes that do not
940** have write permission on the directory containing the database file want
941** to read the database file, as the WAL and shared memory files must exist
942** in order for the database to be readable.  The fourth parameter to
943** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
944** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
945** WAL mode.  If the integer is -1, then it is overwritten with the current
946** WAL persistence setting.
947**
948** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
949** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
950** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
951** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
952** xDeviceCharacteristics methods. The fourth parameter to
953** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
954** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
955** mode.  If the integer is -1, then it is overwritten with the current
956** zero-damage mode setting.
957**
958** <li>[[SQLITE_FCNTL_OVERWRITE]]
959** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
960** a write transaction to indicate that, unless it is rolled back for some
961** reason, the entire database file will be overwritten by the current
962** transaction. This is used by VACUUM operations.
963**
964** <li>[[SQLITE_FCNTL_VFSNAME]]
965** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
966** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
967** final bottom-level VFS are written into memory obtained from
968** [sqlite3_malloc()] and the result is stored in the char* variable
969** that the fourth parameter of [sqlite3_file_control()] points to.
970** The caller is responsible for freeing the memory when done.  As with
971** all file-control actions, there is no guarantee that this will actually
972** do anything.  Callers should initialize the char* variable to a NULL
973** pointer in case this file-control is not implemented.  This file-control
974** is intended for diagnostic use only.
975**
976** <li>[[SQLITE_FCNTL_VFS_POINTER]]
977** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
978** [VFSes] currently in use.  ^(The argument X in
979** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
980** of type "[sqlite3_vfs] **".  This opcodes will set *X
981** to a pointer to the top-level VFS.)^
982** ^When there are multiple VFS shims in the stack, this opcode finds the
983** upper-most shim only.
984**
985** <li>[[SQLITE_FCNTL_PRAGMA]]
986** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
987** file control is sent to the open [sqlite3_file] object corresponding
988** to the database file to which the pragma statement refers. ^The argument
989** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
990** pointers to strings (char**) in which the second element of the array
991** is the name of the pragma and the third element is the argument to the
992** pragma or NULL if the pragma has no argument.  ^The handler for an
993** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
994** of the char** argument point to a string obtained from [sqlite3_mprintf()]
995** or the equivalent and that string will become the result of the pragma or
996** the error message if the pragma fails. ^If the
997** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
998** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
999** file control returns [SQLITE_OK], then the parser assumes that the
1000** VFS has handled the PRAGMA itself and the parser generates a no-op
1001** prepared statement if result string is NULL, or that returns a copy
1002** of the result string if the string is non-NULL.
1003** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
1004** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
1005** that the VFS encountered an error while handling the [PRAGMA] and the
1006** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
1007** file control occurs at the beginning of pragma statement analysis and so
1008** it is able to override built-in [PRAGMA] statements.
1009**
1010** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
1011** ^The [SQLITE_FCNTL_BUSYHANDLER]
1012** file-control may be invoked by SQLite on the database file handle
1013** shortly after it is opened in order to provide a custom VFS with access
1014** to the connection's busy-handler callback. The argument is of type (void**)
1015** - an array of two (void *) values. The first (void *) actually points
1016** to a function of type (int (*)(void *)). In order to invoke the connection's
1017** busy-handler, this function should be invoked with the second (void *) in
1018** the array as the only argument. If it returns non-zero, then the operation
1019** should be retried. If it returns zero, the custom VFS should abandon the
1020** current operation.
1021**
1022** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
1023** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
1024** to have SQLite generate a
1025** temporary filename using the same algorithm that is followed to generate
1026** temporary filenames for TEMP tables and other internal uses.  The
1027** argument should be a char** which will be filled with the filename
1028** written into memory obtained from [sqlite3_malloc()].  The caller should
1029** invoke [sqlite3_free()] on the result to avoid a memory leak.
1030**
1031** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
1032** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
1033** maximum number of bytes that will be used for memory-mapped I/O.
1034** The argument is a pointer to a value of type sqlite3_int64 that
1035** is an advisory maximum number of bytes in the file to memory map.  The
1036** pointer is overwritten with the old value.  The limit is not changed if
1037** the value originally pointed to is negative, and so the current limit
1038** can be queried by passing in a pointer to a negative number.  This
1039** file-control is used internally to implement [PRAGMA mmap_size].
1040**
1041** <li>[[SQLITE_FCNTL_TRACE]]
1042** The [SQLITE_FCNTL_TRACE] file control provides advisory information
1043** to the VFS about what the higher layers of the SQLite stack are doing.
1044** This file control is used by some VFS activity tracing [shims].
1045** The argument is a zero-terminated string.  Higher layers in the
1046** SQLite stack may generate instances of this file control if
1047** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
1048**
1049** <li>[[SQLITE_FCNTL_HAS_MOVED]]
1050** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
1051** pointer to an integer and it writes a boolean into that integer depending
1052** on whether or not the file has been renamed, moved, or deleted since it
1053** was first opened.
1054**
1055** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
1056** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
1057** underlying native file handle associated with a file handle.  This file
1058** control interprets its argument as a pointer to a native file handle and
1059** writes the resulting value there.
1060**
1061** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
1062** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
1063** opcode causes the xFileControl method to swap the file handle with the one
1064** pointed to by the pArg argument.  This capability is used during testing
1065** and only needs to be supported when SQLITE_TEST is defined.
1066**
1067** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
1068** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
1069** be advantageous to block on the next WAL lock if the lock is not immediately
1070** available.  The WAL subsystem issues this signal during rare
1071** circumstances in order to fix a problem with priority inversion.
1072** Applications should <em>not</em> use this file-control.
1073**
1074** <li>[[SQLITE_FCNTL_ZIPVFS]]
1075** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
1076** VFS should return SQLITE_NOTFOUND for this opcode.
1077**
1078** <li>[[SQLITE_FCNTL_RBU]]
1079** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
1080** the RBU extension only.  All other VFS should return SQLITE_NOTFOUND for
1081** this opcode.
1082**
1083** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
1084** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
1085** the file descriptor is placed in "batch write mode", which
1086** means all subsequent write operations will be deferred and done
1087** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].  Systems
1088** that do not support batch atomic writes will return SQLITE_NOTFOUND.
1089** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
1090** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
1091** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
1092** no VFS interface calls on the same [sqlite3_file] file descriptor
1093** except for calls to the xWrite method and the xFileControl method
1094** with [SQLITE_FCNTL_SIZE_HINT].
1095**
1096** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
1097** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
1098** operations since the previous successful call to
1099** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
1100** This file control returns [SQLITE_OK] if and only if the writes were
1101** all performed successfully and have been committed to persistent storage.
1102** ^Regardless of whether or not it is successful, this file control takes
1103** the file descriptor out of batch write mode so that all subsequent
1104** write operations are independent.
1105** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
1106** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1107**
1108** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
1109** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
1110** operations since the previous successful call to
1111** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
1112** ^This file control takes the file descriptor out of batch write mode
1113** so that all subsequent write operations are independent.
1114** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
1115** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1116**
1117** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]]
1118** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS
1119** to block for up to M milliseconds before failing when attempting to
1120** obtain a file lock using the xLock or xShmLock methods of the VFS.
1121** The parameter is a pointer to a 32-bit signed integer that contains
1122** the value that M is to be set to. Before returning, the 32-bit signed
1123** integer is overwritten with the previous value of M.
1124**
1125** <li>[[SQLITE_FCNTL_DATA_VERSION]]
1126** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
1127** a database file.  The argument is a pointer to a 32-bit unsigned integer.
1128** The "data version" for the pager is written into the pointer.  The
1129** "data version" changes whenever any change occurs to the corresponding
1130** database file, either through SQL statements on the same database
1131** connection or through transactions committed by separate database
1132** connections possibly in other processes. The [sqlite3_total_changes()]
1133** interface can be used to find if any database on the connection has changed,
1134** but that interface responds to changes on TEMP as well as MAIN and does
1135** not provide a mechanism to detect changes to MAIN only.  Also, the
1136** [sqlite3_total_changes()] interface responds to internal changes only and
1137** omits changes made by other database connections.  The
1138** [PRAGMA data_version] command provides a mechanism to detect changes to
1139** a single attached database that occur due to other database connections,
1140** but omits changes implemented by the database connection on which it is
1141** called.  This file control is the only mechanism to detect changes that
1142** happen either internally or externally and that are associated with
1143** a particular attached database.
1144**
1145** <li>[[SQLITE_FCNTL_CKPT_START]]
1146** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint
1147** in wal mode before the client starts to copy pages from the wal
1148** file to the database file.
1149**
1150** <li>[[SQLITE_FCNTL_CKPT_DONE]]
1151** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint
1152** in wal mode after the client has finished copying pages from the wal
1153** file to the database file, but before the *-shm file is updated to
1154** record the fact that the pages have been checkpointed.
1155** </ul>
1156**
1157** <li>[[SQLITE_FCNTL_EXTERNAL_READER]]
1158** The EXPERIMENTAL [SQLITE_FCNTL_EXTERNAL_READER] opcode is used to detect
1159** whether or not there is a database client in another process with a wal-mode
1160** transaction open on the database or not. It is only available on unix.The
1161** (void*) argument passed with this file-control should be a pointer to a
1162** value of type (int). The integer value is set to 1 if the database is a wal
1163** mode database and there exists at least one client in another process that
1164** currently has an SQL transaction open on the database. It is set to 0 if
1165** the database is not a wal-mode db, or if there is no such connection in any
1166** other process. This opcode cannot be used to detect transactions opened
1167** by clients within the current process, only within other processes.
1168** </ul>
1169**
1170** <li>[[SQLITE_FCNTL_CKSM_FILE]]
1171** Used by the cksmvfs VFS module only.
1172** </ul>
1173*/
1174#define SQLITE_FCNTL_LOCKSTATE               1
1175#define SQLITE_FCNTL_GET_LOCKPROXYFILE       2
1176#define SQLITE_FCNTL_SET_LOCKPROXYFILE       3
1177#define SQLITE_FCNTL_LAST_ERRNO              4
1178#define SQLITE_FCNTL_SIZE_HINT               5
1179#define SQLITE_FCNTL_CHUNK_SIZE              6
1180#define SQLITE_FCNTL_FILE_POINTER            7
1181#define SQLITE_FCNTL_SYNC_OMITTED            8
1182#define SQLITE_FCNTL_WIN32_AV_RETRY          9
1183#define SQLITE_FCNTL_PERSIST_WAL            10
1184#define SQLITE_FCNTL_OVERWRITE              11
1185#define SQLITE_FCNTL_VFSNAME                12
1186#define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
1187#define SQLITE_FCNTL_PRAGMA                 14
1188#define SQLITE_FCNTL_BUSYHANDLER            15
1189#define SQLITE_FCNTL_TEMPFILENAME           16
1190#define SQLITE_FCNTL_MMAP_SIZE              18
1191#define SQLITE_FCNTL_TRACE                  19
1192#define SQLITE_FCNTL_HAS_MOVED              20
1193#define SQLITE_FCNTL_SYNC                   21
1194#define SQLITE_FCNTL_COMMIT_PHASETWO        22
1195#define SQLITE_FCNTL_WIN32_SET_HANDLE       23
1196#define SQLITE_FCNTL_WAL_BLOCK              24
1197#define SQLITE_FCNTL_ZIPVFS                 25
1198#define SQLITE_FCNTL_RBU                    26
1199#define SQLITE_FCNTL_VFS_POINTER            27
1200#define SQLITE_FCNTL_JOURNAL_POINTER        28
1201#define SQLITE_FCNTL_WIN32_GET_HANDLE       29
1202#define SQLITE_FCNTL_PDB                    30
1203#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE     31
1204#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE    32
1205#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE  33
1206#define SQLITE_FCNTL_LOCK_TIMEOUT           34
1207#define SQLITE_FCNTL_DATA_VERSION           35
1208#define SQLITE_FCNTL_SIZE_LIMIT             36
1209#define SQLITE_FCNTL_CKPT_DONE              37
1210#define SQLITE_FCNTL_RESERVE_BYTES          38
1211#define SQLITE_FCNTL_CKPT_START             39
1212#define SQLITE_FCNTL_EXTERNAL_READER        40
1213#define SQLITE_FCNTL_CKSM_FILE              41
1214
1215/* deprecated names */
1216#define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
1217#define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
1218#define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO
1219
1220
1221/*
1222** CAPI3REF: Mutex Handle
1223**
1224** The mutex module within SQLite defines [sqlite3_mutex] to be an
1225** abstract type for a mutex object.  The SQLite core never looks
1226** at the internal representation of an [sqlite3_mutex].  It only
1227** deals with pointers to the [sqlite3_mutex] object.
1228**
1229** Mutexes are created using [sqlite3_mutex_alloc()].
1230*/
1231typedef struct sqlite3_mutex sqlite3_mutex;
1232
1233/*
1234** CAPI3REF: Loadable Extension Thunk
1235**
1236** A pointer to the opaque sqlite3_api_routines structure is passed as
1237** the third parameter to entry points of [loadable extensions].  This
1238** structure must be typedefed in order to work around compiler warnings
1239** on some platforms.
1240*/
1241typedef struct sqlite3_api_routines sqlite3_api_routines;
1242
1243/*
1244** CAPI3REF: OS Interface Object
1245**
1246** An instance of the sqlite3_vfs object defines the interface between
1247** the SQLite core and the underlying operating system.  The "vfs"
1248** in the name of the object stands for "virtual file system".  See
1249** the [VFS | VFS documentation] for further information.
1250**
1251** The VFS interface is sometimes extended by adding new methods onto
1252** the end.  Each time such an extension occurs, the iVersion field
1253** is incremented.  The iVersion value started out as 1 in
1254** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
1255** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
1256** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6].  Additional fields
1257** may be appended to the sqlite3_vfs object and the iVersion value
1258** may increase again in future versions of SQLite.
1259** Note that due to an oversight, the structure
1260** of the sqlite3_vfs object changed in the transition from
1261** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
1262** and yet the iVersion field was not increased.
1263**
1264** The szOsFile field is the size of the subclassed [sqlite3_file]
1265** structure used by this VFS.  mxPathname is the maximum length of
1266** a pathname in this VFS.
1267**
1268** Registered sqlite3_vfs objects are kept on a linked list formed by
1269** the pNext pointer.  The [sqlite3_vfs_register()]
1270** and [sqlite3_vfs_unregister()] interfaces manage this list
1271** in a thread-safe way.  The [sqlite3_vfs_find()] interface
1272** searches the list.  Neither the application code nor the VFS
1273** implementation should use the pNext pointer.
1274**
1275** The pNext field is the only field in the sqlite3_vfs
1276** structure that SQLite will ever modify.  SQLite will only access
1277** or modify this field while holding a particular static mutex.
1278** The application should never modify anything within the sqlite3_vfs
1279** object once the object has been registered.
1280**
1281** The zName field holds the name of the VFS module.  The name must
1282** be unique across all VFS modules.
1283**
1284** [[sqlite3_vfs.xOpen]]
1285** ^SQLite guarantees that the zFilename parameter to xOpen
1286** is either a NULL pointer or string obtained
1287** from xFullPathname() with an optional suffix added.
1288** ^If a suffix is added to the zFilename parameter, it will
1289** consist of a single "-" character followed by no more than
1290** 11 alphanumeric and/or "-" characters.
1291** ^SQLite further guarantees that
1292** the string will be valid and unchanged until xClose() is
1293** called. Because of the previous sentence,
1294** the [sqlite3_file] can safely store a pointer to the
1295** filename if it needs to remember the filename for some reason.
1296** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1297** must invent its own temporary name for the file.  ^Whenever the
1298** xFilename parameter is NULL it will also be the case that the
1299** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1300**
1301** The flags argument to xOpen() includes all bits set in
1302** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
1303** or [sqlite3_open16()] is used, then flags includes at least
1304** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1305** If xOpen() opens a file read-only then it sets *pOutFlags to
1306** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
1307**
1308** ^(SQLite will also add one of the following flags to the xOpen()
1309** call, depending on the object being opened:
1310**
1311** <ul>
1312** <li>  [SQLITE_OPEN_MAIN_DB]
1313** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
1314** <li>  [SQLITE_OPEN_TEMP_DB]
1315** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
1316** <li>  [SQLITE_OPEN_TRANSIENT_DB]
1317** <li>  [SQLITE_OPEN_SUBJOURNAL]
1318** <li>  [SQLITE_OPEN_SUPER_JOURNAL]
1319** <li>  [SQLITE_OPEN_WAL]
1320** </ul>)^
1321**
1322** The file I/O implementation can use the object type flags to
1323** change the way it deals with files.  For example, an application
1324** that does not care about crash recovery or rollback might make
1325** the open of a journal file a no-op.  Writes to this journal would
1326** also be no-ops, and any attempt to read the journal would return
1327** SQLITE_IOERR.  Or the implementation might recognize that a database
1328** file will be doing page-aligned sector reads and writes in a random
1329** order and set up its I/O subsystem accordingly.
1330**
1331** SQLite might also add one of the following flags to the xOpen method:
1332**
1333** <ul>
1334** <li> [SQLITE_OPEN_DELETEONCLOSE]
1335** <li> [SQLITE_OPEN_EXCLUSIVE]
1336** </ul>
1337**
1338** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1339** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
1340** will be set for TEMP databases and their journals, transient
1341** databases, and subjournals.
1342**
1343** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1344** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1345** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1346** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1347** SQLITE_OPEN_CREATE, is used to indicate that file should always
1348** be created, and that it is an error if it already exists.
1349** It is <i>not</i> used to indicate the file should be opened
1350** for exclusive access.
1351**
1352** ^At least szOsFile bytes of memory are allocated by SQLite
1353** to hold the [sqlite3_file] structure passed as the third
1354** argument to xOpen.  The xOpen method does not have to
1355** allocate the structure; it should just fill it in.  Note that
1356** the xOpen method must set the sqlite3_file.pMethods to either
1357** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
1358** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
1359** element will be valid after xOpen returns regardless of the success
1360** or failure of the xOpen call.
1361**
1362** [[sqlite3_vfs.xAccess]]
1363** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1364** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1365** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1366** to test whether a file is at least readable.  The SQLITE_ACCESS_READ
1367** flag is never actually used and is not implemented in the built-in
1368** VFSes of SQLite.  The file is named by the second argument and can be a
1369** directory. The xAccess method returns [SQLITE_OK] on success or some
1370** non-zero error code if there is an I/O error or if the name of
1371** the file given in the second argument is illegal.  If SQLITE_OK
1372** is returned, then non-zero or zero is written into *pResOut to indicate
1373** whether or not the file is accessible.
1374**
1375** ^SQLite will always allocate at least mxPathname+1 bytes for the
1376** output buffer xFullPathname.  The exact size of the output buffer
1377** is also passed as a parameter to both  methods. If the output buffer
1378** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1379** handled as a fatal error by SQLite, vfs implementations should endeavor
1380** to prevent this by setting mxPathname to a sufficiently large value.
1381**
1382** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1383** interfaces are not strictly a part of the filesystem, but they are
1384** included in the VFS structure for completeness.
1385** The xRandomness() function attempts to return nBytes bytes
1386** of good-quality randomness into zOut.  The return value is
1387** the actual number of bytes of randomness obtained.
1388** The xSleep() method causes the calling thread to sleep for at
1389** least the number of microseconds given.  ^The xCurrentTime()
1390** method returns a Julian Day Number for the current date and time as
1391** a floating point value.
1392** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1393** Day Number multiplied by 86400000 (the number of milliseconds in
1394** a 24-hour day).
1395** ^SQLite will use the xCurrentTimeInt64() method to get the current
1396** date and time if that method is available (if iVersion is 2 or
1397** greater and the function pointer is not NULL) and will fall back
1398** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1399**
1400** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1401** are not used by the SQLite core.  These optional interfaces are provided
1402** by some VFSes to facilitate testing of the VFS code. By overriding
1403** system calls with functions under its control, a test program can
1404** simulate faults and error conditions that would otherwise be difficult
1405** or impossible to induce.  The set of system calls that can be overridden
1406** varies from one VFS to another, and from one version of the same VFS to the
1407** next.  Applications that use these interfaces must be prepared for any
1408** or all of these interfaces to be NULL or for their behavior to change
1409** from one release to the next.  Applications must not attempt to access
1410** any of these methods if the iVersion of the VFS is less than 3.
1411*/
1412typedef struct sqlite3_vfs sqlite3_vfs;
1413typedef void (*sqlite3_syscall_ptr)(void);
1414struct sqlite3_vfs {
1415  int iVersion;            /* Structure version number (currently 3) */
1416  int szOsFile;            /* Size of subclassed sqlite3_file */
1417  int mxPathname;          /* Maximum file pathname length */
1418  sqlite3_vfs *pNext;      /* Next registered VFS */
1419  const char *zName;       /* Name of this virtual file system */
1420  void *pAppData;          /* Pointer to application-specific data */
1421  int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1422               int flags, int *pOutFlags);
1423  int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1424  int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1425  int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1426  void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1427  void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1428  void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1429  void (*xDlClose)(sqlite3_vfs*, void*);
1430  int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1431  int (*xSleep)(sqlite3_vfs*, int microseconds);
1432  int (*xCurrentTime)(sqlite3_vfs*, double*);
1433  int (*xGetLastError)(sqlite3_vfs*, int, char *);
1434  /*
1435  ** The methods above are in version 1 of the sqlite_vfs object
1436  ** definition.  Those that follow are added in version 2 or later
1437  */
1438  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1439  /*
1440  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1441  ** Those below are for version 3 and greater.
1442  */
1443  int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1444  sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1445  const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1446  /*
1447  ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1448  ** New fields may be appended in future versions.  The iVersion
1449  ** value will increment whenever this happens.
1450  */
1451};
1452
1453/*
1454** CAPI3REF: Flags for the xAccess VFS method
1455**
1456** These integer constants can be used as the third parameter to
1457** the xAccess method of an [sqlite3_vfs] object.  They determine
1458** what kind of permissions the xAccess method is looking for.
1459** With SQLITE_ACCESS_EXISTS, the xAccess method
1460** simply checks whether the file exists.
1461** With SQLITE_ACCESS_READWRITE, the xAccess method
1462** checks whether the named directory is both readable and writable
1463** (in other words, if files can be added, removed, and renamed within
1464** the directory).
1465** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1466** [temp_store_directory pragma], though this could change in a future
1467** release of SQLite.
1468** With SQLITE_ACCESS_READ, the xAccess method
1469** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
1470** currently unused, though it might be used in a future release of
1471** SQLite.
1472*/
1473#define SQLITE_ACCESS_EXISTS    0
1474#define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
1475#define SQLITE_ACCESS_READ      2   /* Unused */
1476
1477/*
1478** CAPI3REF: Flags for the xShmLock VFS method
1479**
1480** These integer constants define the various locking operations
1481** allowed by the xShmLock method of [sqlite3_io_methods].  The
1482** following are the only legal combinations of flags to the
1483** xShmLock method:
1484**
1485** <ul>
1486** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1487** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1488** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1489** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1490** </ul>
1491**
1492** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1493** was given on the corresponding lock.
1494**
1495** The xShmLock method can transition between unlocked and SHARED or
1496** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
1497** and EXCLUSIVE.
1498*/
1499#define SQLITE_SHM_UNLOCK       1
1500#define SQLITE_SHM_LOCK         2
1501#define SQLITE_SHM_SHARED       4
1502#define SQLITE_SHM_EXCLUSIVE    8
1503
1504/*
1505** CAPI3REF: Maximum xShmLock index
1506**
1507** The xShmLock method on [sqlite3_io_methods] may use values
1508** between 0 and this upper bound as its "offset" argument.
1509** The SQLite core will never attempt to acquire or release a
1510** lock outside of this range
1511*/
1512#define SQLITE_SHM_NLOCK        8
1513
1514
1515/*
1516** CAPI3REF: Initialize The SQLite Library
1517**
1518** ^The sqlite3_initialize() routine initializes the
1519** SQLite library.  ^The sqlite3_shutdown() routine
1520** deallocates any resources that were allocated by sqlite3_initialize().
1521** These routines are designed to aid in process initialization and
1522** shutdown on embedded systems.  Workstation applications using
1523** SQLite normally do not need to invoke either of these routines.
1524**
1525** A call to sqlite3_initialize() is an "effective" call if it is
1526** the first time sqlite3_initialize() is invoked during the lifetime of
1527** the process, or if it is the first time sqlite3_initialize() is invoked
1528** following a call to sqlite3_shutdown().  ^(Only an effective call
1529** of sqlite3_initialize() does any initialization.  All other calls
1530** are harmless no-ops.)^
1531**
1532** A call to sqlite3_shutdown() is an "effective" call if it is the first
1533** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
1534** an effective call to sqlite3_shutdown() does any deinitialization.
1535** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1536**
1537** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1538** is not.  The sqlite3_shutdown() interface must only be called from a
1539** single thread.  All open [database connections] must be closed and all
1540** other SQLite resources must be deallocated prior to invoking
1541** sqlite3_shutdown().
1542**
1543** Among other things, ^sqlite3_initialize() will invoke
1544** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
1545** will invoke sqlite3_os_end().
1546**
1547** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1548** ^If for some reason, sqlite3_initialize() is unable to initialize
1549** the library (perhaps it is unable to allocate a needed resource such
1550** as a mutex) it returns an [error code] other than [SQLITE_OK].
1551**
1552** ^The sqlite3_initialize() routine is called internally by many other
1553** SQLite interfaces so that an application usually does not need to
1554** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
1555** calls sqlite3_initialize() so the SQLite library will be automatically
1556** initialized when [sqlite3_open()] is called if it has not be initialized
1557** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1558** compile-time option, then the automatic calls to sqlite3_initialize()
1559** are omitted and the application must call sqlite3_initialize() directly
1560** prior to using any other SQLite interface.  For maximum portability,
1561** it is recommended that applications always invoke sqlite3_initialize()
1562** directly prior to using any other SQLite interface.  Future releases
1563** of SQLite may require this.  In other words, the behavior exhibited
1564** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1565** default behavior in some future release of SQLite.
1566**
1567** The sqlite3_os_init() routine does operating-system specific
1568** initialization of the SQLite library.  The sqlite3_os_end()
1569** routine undoes the effect of sqlite3_os_init().  Typical tasks
1570** performed by these routines include allocation or deallocation
1571** of static resources, initialization of global variables,
1572** setting up a default [sqlite3_vfs] module, or setting up
1573** a default configuration using [sqlite3_config()].
1574**
1575** The application should never invoke either sqlite3_os_init()
1576** or sqlite3_os_end() directly.  The application should only invoke
1577** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
1578** interface is called automatically by sqlite3_initialize() and
1579** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
1580** implementations for sqlite3_os_init() and sqlite3_os_end()
1581** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1582** When [custom builds | built for other platforms]
1583** (using the [SQLITE_OS_OTHER=1] compile-time
1584** option) the application must supply a suitable implementation for
1585** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
1586** implementation of sqlite3_os_init() or sqlite3_os_end()
1587** must return [SQLITE_OK] on success and some other [error code] upon
1588** failure.
1589*/
1590int sqlite3_initialize(void);
1591int sqlite3_shutdown(void);
1592int sqlite3_os_init(void);
1593int sqlite3_os_end(void);
1594
1595/*
1596** CAPI3REF: Configuring The SQLite Library
1597**
1598** The sqlite3_config() interface is used to make global configuration
1599** changes to SQLite in order to tune SQLite to the specific needs of
1600** the application.  The default configuration is recommended for most
1601** applications and so this routine is usually not necessary.  It is
1602** provided to support rare applications with unusual needs.
1603**
1604** <b>The sqlite3_config() interface is not threadsafe. The application
1605** must ensure that no other SQLite interfaces are invoked by other
1606** threads while sqlite3_config() is running.</b>
1607**
1608** The sqlite3_config() interface
1609** may only be invoked prior to library initialization using
1610** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1611** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1612** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1613** Note, however, that ^sqlite3_config() can be called as part of the
1614** implementation of an application-defined [sqlite3_os_init()].
1615**
1616** The first argument to sqlite3_config() is an integer
1617** [configuration option] that determines
1618** what property of SQLite is to be configured.  Subsequent arguments
1619** vary depending on the [configuration option]
1620** in the first argument.
1621**
1622** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1623** ^If the option is unknown or SQLite is unable to set the option
1624** then this routine returns a non-zero [error code].
1625*/
1626int sqlite3_config(int, ...);
1627
1628/*
1629** CAPI3REF: Configure database connections
1630** METHOD: sqlite3
1631**
1632** The sqlite3_db_config() interface is used to make configuration
1633** changes to a [database connection].  The interface is similar to
1634** [sqlite3_config()] except that the changes apply to a single
1635** [database connection] (specified in the first argument).
1636**
1637** The second argument to sqlite3_db_config(D,V,...)  is the
1638** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1639** that indicates what aspect of the [database connection] is being configured.
1640** Subsequent arguments vary depending on the configuration verb.
1641**
1642** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1643** the call is considered successful.
1644*/
1645int sqlite3_db_config(sqlite3*, int op, ...);
1646
1647/*
1648** CAPI3REF: Memory Allocation Routines
1649**
1650** An instance of this object defines the interface between SQLite
1651** and low-level memory allocation routines.
1652**
1653** This object is used in only one place in the SQLite interface.
1654** A pointer to an instance of this object is the argument to
1655** [sqlite3_config()] when the configuration option is
1656** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1657** By creating an instance of this object
1658** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1659** during configuration, an application can specify an alternative
1660** memory allocation subsystem for SQLite to use for all of its
1661** dynamic memory needs.
1662**
1663** Note that SQLite comes with several [built-in memory allocators]
1664** that are perfectly adequate for the overwhelming majority of applications
1665** and that this object is only useful to a tiny minority of applications
1666** with specialized memory allocation requirements.  This object is
1667** also used during testing of SQLite in order to specify an alternative
1668** memory allocator that simulates memory out-of-memory conditions in
1669** order to verify that SQLite recovers gracefully from such
1670** conditions.
1671**
1672** The xMalloc, xRealloc, and xFree methods must work like the
1673** malloc(), realloc() and free() functions from the standard C library.
1674** ^SQLite guarantees that the second argument to
1675** xRealloc is always a value returned by a prior call to xRoundup.
1676**
1677** xSize should return the allocated size of a memory allocation
1678** previously obtained from xMalloc or xRealloc.  The allocated size
1679** is always at least as big as the requested size but may be larger.
1680**
1681** The xRoundup method returns what would be the allocated size of
1682** a memory allocation given a particular requested size.  Most memory
1683** allocators round up memory allocations at least to the next multiple
1684** of 8.  Some allocators round up to a larger multiple or to a power of 2.
1685** Every memory allocation request coming in through [sqlite3_malloc()]
1686** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
1687** that causes the corresponding memory allocation to fail.
1688**
1689** The xInit method initializes the memory allocator.  For example,
1690** it might allocate any required mutexes or initialize internal data
1691** structures.  The xShutdown method is invoked (indirectly) by
1692** [sqlite3_shutdown()] and should deallocate any resources acquired
1693** by xInit.  The pAppData pointer is used as the only parameter to
1694** xInit and xShutdown.
1695**
1696** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes
1697** the xInit method, so the xInit method need not be threadsafe.  The
1698** xShutdown method is only called from [sqlite3_shutdown()] so it does
1699** not need to be threadsafe either.  For all other methods, SQLite
1700** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1701** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1702** it is by default) and so the methods are automatically serialized.
1703** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1704** methods must be threadsafe or else make their own arrangements for
1705** serialization.
1706**
1707** SQLite will never invoke xInit() more than once without an intervening
1708** call to xShutdown().
1709*/
1710typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1711struct sqlite3_mem_methods {
1712  void *(*xMalloc)(int);         /* Memory allocation function */
1713  void (*xFree)(void*);          /* Free a prior allocation */
1714  void *(*xRealloc)(void*,int);  /* Resize an allocation */
1715  int (*xSize)(void*);           /* Return the size of an allocation */
1716  int (*xRoundup)(int);          /* Round up request size to allocation size */
1717  int (*xInit)(void*);           /* Initialize the memory allocator */
1718  void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
1719  void *pAppData;                /* Argument to xInit() and xShutdown() */
1720};
1721
1722/*
1723** CAPI3REF: Configuration Options
1724** KEYWORDS: {configuration option}
1725**
1726** These constants are the available integer configuration options that
1727** can be passed as the first argument to the [sqlite3_config()] interface.
1728**
1729** New configuration options may be added in future releases of SQLite.
1730** Existing configuration options might be discontinued.  Applications
1731** should check the return code from [sqlite3_config()] to make sure that
1732** the call worked.  The [sqlite3_config()] interface will return a
1733** non-zero [error code] if a discontinued or unsupported configuration option
1734** is invoked.
1735**
1736** <dl>
1737** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1738** <dd>There are no arguments to this option.  ^This option sets the
1739** [threading mode] to Single-thread.  In other words, it disables
1740** all mutexing and puts SQLite into a mode where it can only be used
1741** by a single thread.   ^If SQLite is compiled with
1742** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1743** it is not possible to change the [threading mode] from its default
1744** value of Single-thread and so [sqlite3_config()] will return
1745** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1746** configuration option.</dd>
1747**
1748** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1749** <dd>There are no arguments to this option.  ^This option sets the
1750** [threading mode] to Multi-thread.  In other words, it disables
1751** mutexing on [database connection] and [prepared statement] objects.
1752** The application is responsible for serializing access to
1753** [database connections] and [prepared statements].  But other mutexes
1754** are enabled so that SQLite will be safe to use in a multi-threaded
1755** environment as long as no two threads attempt to use the same
1756** [database connection] at the same time.  ^If SQLite is compiled with
1757** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1758** it is not possible to set the Multi-thread [threading mode] and
1759** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1760** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1761**
1762** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1763** <dd>There are no arguments to this option.  ^This option sets the
1764** [threading mode] to Serialized. In other words, this option enables
1765** all mutexes including the recursive
1766** mutexes on [database connection] and [prepared statement] objects.
1767** In this mode (which is the default when SQLite is compiled with
1768** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1769** to [database connections] and [prepared statements] so that the
1770** application is free to use the same [database connection] or the
1771** same [prepared statement] in different threads at the same time.
1772** ^If SQLite is compiled with
1773** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1774** it is not possible to set the Serialized [threading mode] and
1775** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1776** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1777**
1778** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1779** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1780** a pointer to an instance of the [sqlite3_mem_methods] structure.
1781** The argument specifies
1782** alternative low-level memory allocation routines to be used in place of
1783** the memory allocation routines built into SQLite.)^ ^SQLite makes
1784** its own private copy of the content of the [sqlite3_mem_methods] structure
1785** before the [sqlite3_config()] call returns.</dd>
1786**
1787** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1788** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1789** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1790** The [sqlite3_mem_methods]
1791** structure is filled with the currently defined memory allocation routines.)^
1792** This option can be used to overload the default memory allocation
1793** routines with a wrapper that simulations memory allocation failure or
1794** tracks memory usage, for example. </dd>
1795**
1796** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
1797** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
1798** type int, interpreted as a boolean, which if true provides a hint to
1799** SQLite that it should avoid large memory allocations if possible.
1800** SQLite will run faster if it is free to make large memory allocations,
1801** but some application might prefer to run slower in exchange for
1802** guarantees about memory fragmentation that are possible if large
1803** allocations are avoided.  This hint is normally off.
1804** </dd>
1805**
1806** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1807** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1808** interpreted as a boolean, which enables or disables the collection of
1809** memory allocation statistics. ^(When memory allocation statistics are
1810** disabled, the following SQLite interfaces become non-operational:
1811**   <ul>
1812**   <li> [sqlite3_hard_heap_limit64()]
1813**   <li> [sqlite3_memory_used()]
1814**   <li> [sqlite3_memory_highwater()]
1815**   <li> [sqlite3_soft_heap_limit64()]
1816**   <li> [sqlite3_status64()]
1817**   </ul>)^
1818** ^Memory allocation statistics are enabled by default unless SQLite is
1819** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1820** allocation statistics are disabled by default.
1821** </dd>
1822**
1823** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1824** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
1825** </dd>
1826**
1827** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1828** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
1829** that SQLite can use for the database page cache with the default page
1830** cache implementation.
1831** This configuration option is a no-op if an application-defined page
1832** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
1833** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1834** 8-byte aligned memory (pMem), the size of each page cache line (sz),
1835** and the number of cache lines (N).
1836** The sz argument should be the size of the largest database page
1837** (a power of two between 512 and 65536) plus some extra bytes for each
1838** page header.  ^The number of extra bytes needed by the page header
1839** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
1840** ^It is harmless, apart from the wasted memory,
1841** for the sz parameter to be larger than necessary.  The pMem
1842** argument must be either a NULL pointer or a pointer to an 8-byte
1843** aligned block of memory of at least sz*N bytes, otherwise
1844** subsequent behavior is undefined.
1845** ^When pMem is not NULL, SQLite will strive to use the memory provided
1846** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
1847** a page cache line is larger than sz bytes or if all of the pMem buffer
1848** is exhausted.
1849** ^If pMem is NULL and N is non-zero, then each database connection
1850** does an initial bulk allocation for page cache memory
1851** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
1852** of -1024*N bytes if N is negative, . ^If additional
1853** page cache memory is needed beyond what is provided by the initial
1854** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
1855** additional cache line. </dd>
1856**
1857** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1858** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1859** that SQLite will use for all of its dynamic memory allocation needs
1860** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
1861** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1862** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1863** [SQLITE_ERROR] if invoked otherwise.
1864** ^There are three arguments to SQLITE_CONFIG_HEAP:
1865** An 8-byte aligned pointer to the memory,
1866** the number of bytes in the memory buffer, and the minimum allocation size.
1867** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1868** to using its default memory allocator (the system malloc() implementation),
1869** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
1870** memory pointer is not NULL then the alternative memory
1871** allocator is engaged to handle all of SQLites memory allocation needs.
1872** The first pointer (the memory pointer) must be aligned to an 8-byte
1873** boundary or subsequent behavior of SQLite will be undefined.
1874** The minimum allocation size is capped at 2**12. Reasonable values
1875** for the minimum allocation size are 2**5 through 2**8.</dd>
1876**
1877** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1878** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1879** pointer to an instance of the [sqlite3_mutex_methods] structure.
1880** The argument specifies alternative low-level mutex routines to be used
1881** in place the mutex routines built into SQLite.)^  ^SQLite makes a copy of
1882** the content of the [sqlite3_mutex_methods] structure before the call to
1883** [sqlite3_config()] returns. ^If SQLite is compiled with
1884** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1885** the entire mutexing subsystem is omitted from the build and hence calls to
1886** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1887** return [SQLITE_ERROR].</dd>
1888**
1889** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1890** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1891** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
1892** [sqlite3_mutex_methods]
1893** structure is filled with the currently defined mutex routines.)^
1894** This option can be used to overload the default mutex allocation
1895** routines with a wrapper used to track mutex usage for performance
1896** profiling or testing, for example.   ^If SQLite is compiled with
1897** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1898** the entire mutexing subsystem is omitted from the build and hence calls to
1899** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1900** return [SQLITE_ERROR].</dd>
1901**
1902** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1903** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1904** the default size of lookaside memory on each [database connection].
1905** The first argument is the
1906** size of each lookaside buffer slot and the second is the number of
1907** slots allocated to each database connection.)^  ^(SQLITE_CONFIG_LOOKASIDE
1908** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1909** option to [sqlite3_db_config()] can be used to change the lookaside
1910** configuration on individual connections.)^ </dd>
1911**
1912** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1913** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1914** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
1915** the interface to a custom page cache implementation.)^
1916** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1917**
1918** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1919** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1920** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies of
1921** the current page cache implementation into that object.)^ </dd>
1922**
1923** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1924** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1925** global [error log].
1926** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1927** function with a call signature of void(*)(void*,int,const char*),
1928** and a pointer to void. ^If the function pointer is not NULL, it is
1929** invoked by [sqlite3_log()] to process each logging event.  ^If the
1930** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1931** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1932** passed through as the first parameter to the application-defined logger
1933** function whenever that function is invoked.  ^The second parameter to
1934** the logger function is a copy of the first parameter to the corresponding
1935** [sqlite3_log()] call and is intended to be a [result code] or an
1936** [extended result code].  ^The third parameter passed to the logger is
1937** log message after formatting via [sqlite3_snprintf()].
1938** The SQLite logging interface is not reentrant; the logger function
1939** supplied by the application must not invoke any SQLite interface.
1940** In a multi-threaded application, the application-defined logger
1941** function must be threadsafe. </dd>
1942**
1943** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1944** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1945** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1946** then URI handling is globally disabled.)^ ^If URI handling is globally
1947** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1948** [sqlite3_open16()] or
1949** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1950** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1951** connection is opened. ^If it is globally disabled, filenames are
1952** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1953** database connection is opened. ^(By default, URI handling is globally
1954** disabled. The default value may be changed by compiling with the
1955** [SQLITE_USE_URI] symbol defined.)^
1956**
1957** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1958** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1959** argument which is interpreted as a boolean in order to enable or disable
1960** the use of covering indices for full table scans in the query optimizer.
1961** ^The default setting is determined
1962** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1963** if that compile-time option is omitted.
1964** The ability to disable the use of covering indices for full table scans
1965** is because some incorrectly coded legacy applications might malfunction
1966** when the optimization is enabled.  Providing the ability to
1967** disable the optimization allows the older, buggy application code to work
1968** without change even with newer versions of SQLite.
1969**
1970** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1971** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1972** <dd> These options are obsolete and should not be used by new code.
1973** They are retained for backwards compatibility but are now no-ops.
1974** </dd>
1975**
1976** [[SQLITE_CONFIG_SQLLOG]]
1977** <dt>SQLITE_CONFIG_SQLLOG
1978** <dd>This option is only available if sqlite is compiled with the
1979** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1980** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1981** The second should be of type (void*). The callback is invoked by the library
1982** in three separate circumstances, identified by the value passed as the
1983** fourth parameter. If the fourth parameter is 0, then the database connection
1984** passed as the second argument has just been opened. The third argument
1985** points to a buffer containing the name of the main database file. If the
1986** fourth parameter is 1, then the SQL statement that the third parameter
1987** points to has just been executed. Or, if the fourth parameter is 2, then
1988** the connection being passed as the second parameter is being closed. The
1989** third parameter is passed NULL In this case.  An example of using this
1990** configuration option can be seen in the "test_sqllog.c" source file in
1991** the canonical SQLite source tree.</dd>
1992**
1993** [[SQLITE_CONFIG_MMAP_SIZE]]
1994** <dt>SQLITE_CONFIG_MMAP_SIZE
1995** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1996** that are the default mmap size limit (the default setting for
1997** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1998** ^The default setting can be overridden by each database connection using
1999** either the [PRAGMA mmap_size] command, or by using the
2000** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
2001** will be silently truncated if necessary so that it does not exceed the
2002** compile-time maximum mmap size set by the
2003** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
2004** ^If either argument to this option is negative, then that argument is
2005** changed to its compile-time default.
2006**
2007** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
2008** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
2009** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
2010** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
2011** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
2012** that specifies the maximum size of the created heap.
2013**
2014** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
2015** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
2016** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
2017** is a pointer to an integer and writes into that integer the number of extra
2018** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
2019** The amount of extra space required can change depending on the compiler,
2020** target platform, and SQLite version.
2021**
2022** [[SQLITE_CONFIG_PMASZ]]
2023** <dt>SQLITE_CONFIG_PMASZ
2024** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
2025** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
2026** sorter to that integer.  The default minimum PMA Size is set by the
2027** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
2028** to help with sort operations when multithreaded sorting
2029** is enabled (using the [PRAGMA threads] command) and the amount of content
2030** to be sorted exceeds the page size times the minimum of the
2031** [PRAGMA cache_size] setting and this value.
2032**
2033** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
2034** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
2035** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
2036** becomes the [statement journal] spill-to-disk threshold.
2037** [Statement journals] are held in memory until their size (in bytes)
2038** exceeds this threshold, at which point they are written to disk.
2039** Or if the threshold is -1, statement journals are always held
2040** exclusively in memory.
2041** Since many statement journals never become large, setting the spill
2042** threshold to a value such as 64KiB can greatly reduce the amount of
2043** I/O required to support statement rollback.
2044** The default value for this setting is controlled by the
2045** [SQLITE_STMTJRNL_SPILL] compile-time option.
2046**
2047** [[SQLITE_CONFIG_SORTERREF_SIZE]]
2048** <dt>SQLITE_CONFIG_SORTERREF_SIZE
2049** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
2050** of type (int) - the new value of the sorter-reference size threshold.
2051** Usually, when SQLite uses an external sort to order records according
2052** to an ORDER BY clause, all fields required by the caller are present in the
2053** sorted records. However, if SQLite determines based on the declared type
2054** of a table column that its values are likely to be very large - larger
2055** than the configured sorter-reference size threshold - then a reference
2056** is stored in each sorted record and the required column values loaded
2057** from the database as records are returned in sorted order. The default
2058** value for this option is to never use this optimization. Specifying a
2059** negative value for this option restores the default behaviour.
2060** This option is only available if SQLite is compiled with the
2061** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
2062**
2063** [[SQLITE_CONFIG_MEMDB_MAXSIZE]]
2064** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE
2065** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
2066** [sqlite3_int64] parameter which is the default maximum size for an in-memory
2067** database created using [sqlite3_deserialize()].  This default maximum
2068** size can be adjusted up or down for individual databases using the
2069** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control].  If this
2070** configuration setting is never used, then the default maximum is determined
2071** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option.  If that
2072** compile-time option is not set, then the default maximum is 1073741824.
2073** </dl>
2074*/
2075#define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
2076#define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
2077#define SQLITE_CONFIG_SERIALIZED    3  /* nil */
2078#define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
2079#define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
2080#define SQLITE_CONFIG_SCRATCH       6  /* No longer used */
2081#define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
2082#define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
2083#define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
2084#define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
2085#define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
2086/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
2087#define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
2088#define SQLITE_CONFIG_PCACHE       14  /* no-op */
2089#define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
2090#define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
2091#define SQLITE_CONFIG_URI          17  /* int */
2092#define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
2093#define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
2094#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
2095#define SQLITE_CONFIG_SQLLOG       21  /* xSqllog, void* */
2096#define SQLITE_CONFIG_MMAP_SIZE    22  /* sqlite3_int64, sqlite3_int64 */
2097#define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
2098#define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
2099#define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
2100#define SQLITE_CONFIG_STMTJRNL_SPILL      26  /* int nByte */
2101#define SQLITE_CONFIG_SMALL_MALLOC        27  /* boolean */
2102#define SQLITE_CONFIG_SORTERREF_SIZE      28  /* int nByte */
2103#define SQLITE_CONFIG_MEMDB_MAXSIZE       29  /* sqlite3_int64 */
2104
2105/*
2106** CAPI3REF: Database Connection Configuration Options
2107**
2108** These constants are the available integer configuration options that
2109** can be passed as the second argument to the [sqlite3_db_config()] interface.
2110**
2111** New configuration options may be added in future releases of SQLite.
2112** Existing configuration options might be discontinued.  Applications
2113** should check the return code from [sqlite3_db_config()] to make sure that
2114** the call worked.  ^The [sqlite3_db_config()] interface will return a
2115** non-zero [error code] if a discontinued or unsupported configuration option
2116** is invoked.
2117**
2118** <dl>
2119** [[SQLITE_DBCONFIG_LOOKASIDE]]
2120** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
2121** <dd> ^This option takes three additional arguments that determine the
2122** [lookaside memory allocator] configuration for the [database connection].
2123** ^The first argument (the third parameter to [sqlite3_db_config()] is a
2124** pointer to a memory buffer to use for lookaside memory.
2125** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
2126** may be NULL in which case SQLite will allocate the
2127** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
2128** size of each lookaside buffer slot.  ^The third argument is the number of
2129** slots.  The size of the buffer in the first argument must be greater than
2130** or equal to the product of the second and third arguments.  The buffer
2131** must be aligned to an 8-byte boundary.  ^If the second argument to
2132** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
2133** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
2134** configuration for a database connection can only be changed when that
2135** connection is not currently using lookaside memory, or in other words
2136** when the "current value" returned by
2137** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
2138** Any attempt to change the lookaside memory configuration when lookaside
2139** memory is in use leaves the configuration unchanged and returns
2140** [SQLITE_BUSY].)^</dd>
2141**
2142** [[SQLITE_DBCONFIG_ENABLE_FKEY]]
2143** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
2144** <dd> ^This option is used to enable or disable the enforcement of
2145** [foreign key constraints].  There should be two additional arguments.
2146** The first argument is an integer which is 0 to disable FK enforcement,
2147** positive to enable FK enforcement or negative to leave FK enforcement
2148** unchanged.  The second parameter is a pointer to an integer into which
2149** is written 0 or 1 to indicate whether FK enforcement is off or on
2150** following this call.  The second parameter may be a NULL pointer, in
2151** which case the FK enforcement setting is not reported back. </dd>
2152**
2153** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]]
2154** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
2155** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
2156** There should be two additional arguments.
2157** The first argument is an integer which is 0 to disable triggers,
2158** positive to enable triggers or negative to leave the setting unchanged.
2159** The second parameter is a pointer to an integer into which
2160** is written 0 or 1 to indicate whether triggers are disabled or enabled
2161** following this call.  The second parameter may be a NULL pointer, in
2162** which case the trigger setting is not reported back.
2163**
2164** <p>Originally this option disabled all triggers.  ^(However, since
2165** SQLite version 3.35.0, TEMP triggers are still allowed even if
2166** this option is off.  So, in other words, this option now only disables
2167** triggers in the main database schema or in the schemas of ATTACH-ed
2168** databases.)^ </dd>
2169**
2170** [[SQLITE_DBCONFIG_ENABLE_VIEW]]
2171** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt>
2172** <dd> ^This option is used to enable or disable [CREATE VIEW | views].
2173** There should be two additional arguments.
2174** The first argument is an integer which is 0 to disable views,
2175** positive to enable views or negative to leave the setting unchanged.
2176** The second parameter is a pointer to an integer into which
2177** is written 0 or 1 to indicate whether views are disabled or enabled
2178** following this call.  The second parameter may be a NULL pointer, in
2179** which case the view setting is not reported back.
2180**
2181** <p>Originally this option disabled all views.  ^(However, since
2182** SQLite version 3.35.0, TEMP views are still allowed even if
2183** this option is off.  So, in other words, this option now only disables
2184** views in the main database schema or in the schemas of ATTACH-ed
2185** databases.)^ </dd>
2186**
2187** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]]
2188** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
2189** <dd> ^This option is used to enable or disable the
2190** [fts3_tokenizer()] function which is part of the
2191** [FTS3] full-text search engine extension.
2192** There should be two additional arguments.
2193** The first argument is an integer which is 0 to disable fts3_tokenizer() or
2194** positive to enable fts3_tokenizer() or negative to leave the setting
2195** unchanged.
2196** The second parameter is a pointer to an integer into which
2197** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
2198** following this call.  The second parameter may be a NULL pointer, in
2199** which case the new setting is not reported back. </dd>
2200**
2201** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]]
2202** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
2203** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
2204** interface independently of the [load_extension()] SQL function.
2205** The [sqlite3_enable_load_extension()] API enables or disables both the
2206** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
2207** There should be two additional arguments.
2208** When the first argument to this interface is 1, then only the C-API is
2209** enabled and the SQL function remains disabled.  If the first argument to
2210** this interface is 0, then both the C-API and the SQL function are disabled.
2211** If the first argument is -1, then no changes are made to state of either the
2212** C-API or the SQL function.
2213** The second parameter is a pointer to an integer into which
2214** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
2215** is disabled or enabled following this call.  The second parameter may
2216** be a NULL pointer, in which case the new setting is not reported back.
2217** </dd>
2218**
2219** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
2220** <dd> ^This option is used to change the name of the "main" database
2221** schema.  ^The sole argument is a pointer to a constant UTF8 string
2222** which will become the new schema name in place of "main".  ^SQLite
2223** does not make a copy of the new main schema name string, so the application
2224** must ensure that the argument passed into this DBCONFIG option is unchanged
2225** until after the database connection closes.
2226** </dd>
2227**
2228** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]]
2229** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
2230** <dd> Usually, when a database in wal mode is closed or detached from a
2231** database handle, SQLite checks if this will mean that there are now no
2232** connections at all to the database. If so, it performs a checkpoint
2233** operation before closing the connection. This option may be used to
2234** override this behaviour. The first parameter passed to this operation
2235** is an integer - positive to disable checkpoints-on-close, or zero (the
2236** default) to enable them, and negative to leave the setting unchanged.
2237** The second parameter is a pointer to an integer
2238** into which is written 0 or 1 to indicate whether checkpoints-on-close
2239** have been disabled - 0 if they are not disabled, 1 if they are.
2240** </dd>
2241**
2242** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
2243** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
2244** the [query planner stability guarantee] (QPSG).  When the QPSG is active,
2245** a single SQL query statement will always use the same algorithm regardless
2246** of values of [bound parameters].)^ The QPSG disables some query optimizations
2247** that look at the values of bound parameters, which can make some queries
2248** slower.  But the QPSG has the advantage of more predictable behavior.  With
2249** the QPSG active, SQLite will always use the same query plan in the field as
2250** was used during testing in the lab.
2251** The first argument to this setting is an integer which is 0 to disable
2252** the QPSG, positive to enable QPSG, or negative to leave the setting
2253** unchanged. The second parameter is a pointer to an integer into which
2254** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
2255** following this call.
2256** </dd>
2257**
2258** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
2259** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
2260** include output for any operations performed by trigger programs. This
2261** option is used to set or clear (the default) a flag that governs this
2262** behavior. The first parameter passed to this operation is an integer -
2263** positive to enable output for trigger programs, or zero to disable it,
2264** or negative to leave the setting unchanged.
2265** The second parameter is a pointer to an integer into which is written
2266** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
2267** it is not disabled, 1 if it is.
2268** </dd>
2269**
2270** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
2271** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
2272** [VACUUM] in order to reset a database back to an empty database
2273** with no schema and no content. The following process works even for
2274** a badly corrupted database file:
2275** <ol>
2276** <li> If the database connection is newly opened, make sure it has read the
2277**      database schema by preparing then discarding some query against the
2278**      database, or calling sqlite3_table_column_metadata(), ignoring any
2279**      errors.  This step is only necessary if the application desires to keep
2280**      the database in WAL mode after the reset if it was in WAL mode before
2281**      the reset.
2282** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
2283** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
2284** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
2285** </ol>
2286** Because resetting a database is destructive and irreversible, the
2287** process requires the use of this obscure API and multiple steps to help
2288** ensure that it does not happen by accident.
2289**
2290** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
2291** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
2292** "defensive" flag for a database connection.  When the defensive
2293** flag is enabled, language features that allow ordinary SQL to
2294** deliberately corrupt the database file are disabled.  The disabled
2295** features include but are not limited to the following:
2296** <ul>
2297** <li> The [PRAGMA writable_schema=ON] statement.
2298** <li> The [PRAGMA journal_mode=OFF] statement.
2299** <li> Writes to the [sqlite_dbpage] virtual table.
2300** <li> Direct writes to [shadow tables].
2301** </ul>
2302** </dd>
2303**
2304** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt>
2305** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
2306** "writable_schema" flag. This has the same effect and is logically equivalent
2307** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF].
2308** The first argument to this setting is an integer which is 0 to disable
2309** the writable_schema, positive to enable writable_schema, or negative to
2310** leave the setting unchanged. The second parameter is a pointer to an
2311** integer into which is written 0 or 1 to indicate whether the writable_schema
2312** is enabled or disabled following this call.
2313** </dd>
2314**
2315** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]]
2316** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt>
2317** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates
2318** the legacy behavior of the [ALTER TABLE RENAME] command such it
2319** behaves as it did prior to [version 3.24.0] (2018-06-04).  See the
2320** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for
2321** additional information. This feature can also be turned on and off
2322** using the [PRAGMA legacy_alter_table] statement.
2323** </dd>
2324**
2325** [[SQLITE_DBCONFIG_DQS_DML]]
2326** <dt>SQLITE_DBCONFIG_DQS_DML</td>
2327** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates
2328** the legacy [double-quoted string literal] misfeature for DML statements
2329** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The
2330** default value of this setting is determined by the [-DSQLITE_DQS]
2331** compile-time option.
2332** </dd>
2333**
2334** [[SQLITE_DBCONFIG_DQS_DDL]]
2335** <dt>SQLITE_DBCONFIG_DQS_DDL</td>
2336** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates
2337** the legacy [double-quoted string literal] misfeature for DDL statements,
2338** such as CREATE TABLE and CREATE INDEX. The
2339** default value of this setting is determined by the [-DSQLITE_DQS]
2340** compile-time option.
2341** </dd>
2342**
2343** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]]
2344** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</td>
2345** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to
2346** assume that database schemas are untainted by malicious content.
2347** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite
2348** takes additional defensive steps to protect the application from harm
2349** including:
2350** <ul>
2351** <li> Prohibit the use of SQL functions inside triggers, views,
2352** CHECK constraints, DEFAULT clauses, expression indexes,
2353** partial indexes, or generated columns
2354** unless those functions are tagged with [SQLITE_INNOCUOUS].
2355** <li> Prohibit the use of virtual tables inside of triggers or views
2356** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS].
2357** </ul>
2358** This setting defaults to "on" for legacy compatibility, however
2359** all applications are advised to turn it off if possible. This setting
2360** can also be controlled using the [PRAGMA trusted_schema] statement.
2361** </dd>
2362**
2363** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]]
2364** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</td>
2365** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates
2366** the legacy file format flag.  When activated, this flag causes all newly
2367** created database file to have a schema format version number (the 4-byte
2368** integer found at offset 44 into the database header) of 1.  This in turn
2369** means that the resulting database file will be readable and writable by
2370** any SQLite version back to 3.0.0 ([dateof:3.0.0]).  Without this setting,
2371** newly created databases are generally not understandable by SQLite versions
2372** prior to 3.3.0 ([dateof:3.3.0]).  As these words are written, there
2373** is now scarcely any need to generated database files that are compatible
2374** all the way back to version 3.0.0, and so this setting is of little
2375** practical use, but is provided so that SQLite can continue to claim the
2376** ability to generate new database files that are compatible with  version
2377** 3.0.0.
2378** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on,
2379** the [VACUUM] command will fail with an obscure error when attempting to
2380** process a table with generated columns and a descending index.  This is
2381** not considered a bug since SQLite versions 3.3.0 and earlier do not support
2382** either generated columns or decending indexes.
2383** </dd>
2384** </dl>
2385*/
2386#define SQLITE_DBCONFIG_MAINDBNAME            1000 /* const char* */
2387#define SQLITE_DBCONFIG_LOOKASIDE             1001 /* void* int int */
2388#define SQLITE_DBCONFIG_ENABLE_FKEY           1002 /* int int* */
2389#define SQLITE_DBCONFIG_ENABLE_TRIGGER        1003 /* int int* */
2390#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
2391#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
2392#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE      1006 /* int int* */
2393#define SQLITE_DBCONFIG_ENABLE_QPSG           1007 /* int int* */
2394#define SQLITE_DBCONFIG_TRIGGER_EQP           1008 /* int int* */
2395#define SQLITE_DBCONFIG_RESET_DATABASE        1009 /* int int* */
2396#define SQLITE_DBCONFIG_DEFENSIVE             1010 /* int int* */
2397#define SQLITE_DBCONFIG_WRITABLE_SCHEMA       1011 /* int int* */
2398#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE    1012 /* int int* */
2399#define SQLITE_DBCONFIG_DQS_DML               1013 /* int int* */
2400#define SQLITE_DBCONFIG_DQS_DDL               1014 /* int int* */
2401#define SQLITE_DBCONFIG_ENABLE_VIEW           1015 /* int int* */
2402#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT    1016 /* int int* */
2403#define SQLITE_DBCONFIG_TRUSTED_SCHEMA        1017 /* int int* */
2404#define SQLITE_DBCONFIG_MAX                   1017 /* Largest DBCONFIG */
2405
2406/*
2407** CAPI3REF: Enable Or Disable Extended Result Codes
2408** METHOD: sqlite3
2409**
2410** ^The sqlite3_extended_result_codes() routine enables or disables the
2411** [extended result codes] feature of SQLite. ^The extended result
2412** codes are disabled by default for historical compatibility.
2413*/
2414int sqlite3_extended_result_codes(sqlite3*, int onoff);
2415
2416/*
2417** CAPI3REF: Last Insert Rowid
2418** METHOD: sqlite3
2419**
2420** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
2421** has a unique 64-bit signed
2422** integer key called the [ROWID | "rowid"]. ^The rowid is always available
2423** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
2424** names are not also used by explicitly declared columns. ^If
2425** the table has a column of type [INTEGER PRIMARY KEY] then that column
2426** is another alias for the rowid.
2427**
2428** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
2429** the most recent successful [INSERT] into a rowid table or [virtual table]
2430** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
2431** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
2432** on the database connection D, then sqlite3_last_insert_rowid(D) returns
2433** zero.
2434**
2435** As well as being set automatically as rows are inserted into database
2436** tables, the value returned by this function may be set explicitly by
2437** [sqlite3_set_last_insert_rowid()]
2438**
2439** Some virtual table implementations may INSERT rows into rowid tables as
2440** part of committing a transaction (e.g. to flush data accumulated in memory
2441** to disk). In this case subsequent calls to this function return the rowid
2442** associated with these internal INSERT operations, which leads to
2443** unintuitive results. Virtual table implementations that do write to rowid
2444** tables in this way can avoid this problem by restoring the original
2445** rowid value using [sqlite3_set_last_insert_rowid()] before returning
2446** control to the user.
2447**
2448** ^(If an [INSERT] occurs within a trigger then this routine will
2449** return the [rowid] of the inserted row as long as the trigger is
2450** running. Once the trigger program ends, the value returned
2451** by this routine reverts to what it was before the trigger was fired.)^
2452**
2453** ^An [INSERT] that fails due to a constraint violation is not a
2454** successful [INSERT] and does not change the value returned by this
2455** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
2456** and INSERT OR ABORT make no changes to the return value of this
2457** routine when their insertion fails.  ^(When INSERT OR REPLACE
2458** encounters a constraint violation, it does not fail.  The
2459** INSERT continues to completion after deleting rows that caused
2460** the constraint problem so INSERT OR REPLACE will always change
2461** the return value of this interface.)^
2462**
2463** ^For the purposes of this routine, an [INSERT] is considered to
2464** be successful even if it is subsequently rolled back.
2465**
2466** This function is accessible to SQL statements via the
2467** [last_insert_rowid() SQL function].
2468**
2469** If a separate thread performs a new [INSERT] on the same
2470** database connection while the [sqlite3_last_insert_rowid()]
2471** function is running and thus changes the last insert [rowid],
2472** then the value returned by [sqlite3_last_insert_rowid()] is
2473** unpredictable and might not equal either the old or the new
2474** last insert [rowid].
2475*/
2476sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
2477
2478/*
2479** CAPI3REF: Set the Last Insert Rowid value.
2480** METHOD: sqlite3
2481**
2482** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
2483** set the value returned by calling sqlite3_last_insert_rowid(D) to R
2484** without inserting a row into the database.
2485*/
2486void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
2487
2488/*
2489** CAPI3REF: Count The Number Of Rows Modified
2490** METHOD: sqlite3
2491**
2492** ^These functions return the number of rows modified, inserted or
2493** deleted by the most recently completed INSERT, UPDATE or DELETE
2494** statement on the database connection specified by the only parameter.
2495** The two functions are identical except for the type of the return value
2496** and that if the number of rows modified by the most recent INSERT, UPDATE
2497** or DELETE is greater than the maximum value supported by type "int", then
2498** the return value of sqlite3_changes() is undefined. ^Executing any other
2499** type of SQL statement does not modify the value returned by these functions.
2500**
2501** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
2502** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
2503** [foreign key actions] or [REPLACE] constraint resolution are not counted.
2504**
2505** Changes to a view that are intercepted by
2506** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
2507** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
2508** DELETE statement run on a view is always zero. Only changes made to real
2509** tables are counted.
2510**
2511** Things are more complicated if the sqlite3_changes() function is
2512** executed while a trigger program is running. This may happen if the
2513** program uses the [changes() SQL function], or if some other callback
2514** function invokes sqlite3_changes() directly. Essentially:
2515**
2516** <ul>
2517**   <li> ^(Before entering a trigger program the value returned by
2518**        sqlite3_changes() function is saved. After the trigger program
2519**        has finished, the original value is restored.)^
2520**
2521**   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
2522**        statement sets the value returned by sqlite3_changes()
2523**        upon completion as normal. Of course, this value will not include
2524**        any changes performed by sub-triggers, as the sqlite3_changes()
2525**        value will be saved and restored after each sub-trigger has run.)^
2526** </ul>
2527**
2528** ^This means that if the changes() SQL function (or similar) is used
2529** by the first INSERT, UPDATE or DELETE statement within a trigger, it
2530** returns the value as set when the calling statement began executing.
2531** ^If it is used by the second or subsequent such statement within a trigger
2532** program, the value returned reflects the number of rows modified by the
2533** previous INSERT, UPDATE or DELETE statement within the same trigger.
2534**
2535** If a separate thread makes changes on the same database connection
2536** while [sqlite3_changes()] is running then the value returned
2537** is unpredictable and not meaningful.
2538**
2539** See also:
2540** <ul>
2541** <li> the [sqlite3_total_changes()] interface
2542** <li> the [count_changes pragma]
2543** <li> the [changes() SQL function]
2544** <li> the [data_version pragma]
2545** </ul>
2546*/
2547int sqlite3_changes(sqlite3*);
2548sqlite3_int64 sqlite3_changes64(sqlite3*);
2549
2550/*
2551** CAPI3REF: Total Number Of Rows Modified
2552** METHOD: sqlite3
2553**
2554** ^These functions return the total number of rows inserted, modified or
2555** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2556** since the database connection was opened, including those executed as
2557** part of trigger programs. The two functions are identical except for the
2558** type of the return value and that if the number of rows modified by the
2559** connection exceeds the maximum value supported by type "int", then
2560** the return value of sqlite3_total_changes() is undefined. ^Executing
2561** any other type of SQL statement does not affect the value returned by
2562** sqlite3_total_changes().
2563**
2564** ^Changes made as part of [foreign key actions] are included in the
2565** count, but those made as part of REPLACE constraint resolution are
2566** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2567** are not counted.
2568**
2569** The [sqlite3_total_changes(D)] interface only reports the number
2570** of rows that changed due to SQL statement run against database
2571** connection D.  Any changes by other database connections are ignored.
2572** To detect changes against a database file from other database
2573** connections use the [PRAGMA data_version] command or the
2574** [SQLITE_FCNTL_DATA_VERSION] [file control].
2575**
2576** If a separate thread makes changes on the same database connection
2577** while [sqlite3_total_changes()] is running then the value
2578** returned is unpredictable and not meaningful.
2579**
2580** See also:
2581** <ul>
2582** <li> the [sqlite3_changes()] interface
2583** <li> the [count_changes pragma]
2584** <li> the [changes() SQL function]
2585** <li> the [data_version pragma]
2586** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control]
2587** </ul>
2588*/
2589int sqlite3_total_changes(sqlite3*);
2590sqlite3_int64 sqlite3_total_changes64(sqlite3*);
2591
2592/*
2593** CAPI3REF: Interrupt A Long-Running Query
2594** METHOD: sqlite3
2595**
2596** ^This function causes any pending database operation to abort and
2597** return at its earliest opportunity. This routine is typically
2598** called in response to a user action such as pressing "Cancel"
2599** or Ctrl-C where the user wants a long query operation to halt
2600** immediately.
2601**
2602** ^It is safe to call this routine from a thread different from the
2603** thread that is currently running the database operation.  But it
2604** is not safe to call this routine with a [database connection] that
2605** is closed or might close before sqlite3_interrupt() returns.
2606**
2607** ^If an SQL operation is very nearly finished at the time when
2608** sqlite3_interrupt() is called, then it might not have an opportunity
2609** to be interrupted and might continue to completion.
2610**
2611** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2612** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2613** that is inside an explicit transaction, then the entire transaction
2614** will be rolled back automatically.
2615**
2616** ^The sqlite3_interrupt(D) call is in effect until all currently running
2617** SQL statements on [database connection] D complete.  ^Any new SQL statements
2618** that are started after the sqlite3_interrupt() call and before the
2619** running statement count reaches zero are interrupted as if they had been
2620** running prior to the sqlite3_interrupt() call.  ^New SQL statements
2621** that are started after the running statement count reaches zero are
2622** not effected by the sqlite3_interrupt().
2623** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2624** SQL statements is a no-op and has no effect on SQL statements
2625** that are started after the sqlite3_interrupt() call returns.
2626*/
2627void sqlite3_interrupt(sqlite3*);
2628
2629/*
2630** CAPI3REF: Determine If An SQL Statement Is Complete
2631**
2632** These routines are useful during command-line input to determine if the
2633** currently entered text seems to form a complete SQL statement or
2634** if additional input is needed before sending the text into
2635** SQLite for parsing.  ^These routines return 1 if the input string
2636** appears to be a complete SQL statement.  ^A statement is judged to be
2637** complete if it ends with a semicolon token and is not a prefix of a
2638** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
2639** string literals or quoted identifier names or comments are not
2640** independent tokens (they are part of the token in which they are
2641** embedded) and thus do not count as a statement terminator.  ^Whitespace
2642** and comments that follow the final semicolon are ignored.
2643**
2644** ^These routines return 0 if the statement is incomplete.  ^If a
2645** memory allocation fails, then SQLITE_NOMEM is returned.
2646**
2647** ^These routines do not parse the SQL statements thus
2648** will not detect syntactically incorrect SQL.
2649**
2650** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2651** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2652** automatically by sqlite3_complete16().  If that initialization fails,
2653** then the return value from sqlite3_complete16() will be non-zero
2654** regardless of whether or not the input SQL is complete.)^
2655**
2656** The input to [sqlite3_complete()] must be a zero-terminated
2657** UTF-8 string.
2658**
2659** The input to [sqlite3_complete16()] must be a zero-terminated
2660** UTF-16 string in native byte order.
2661*/
2662int sqlite3_complete(const char *sql);
2663int sqlite3_complete16(const void *sql);
2664
2665/*
2666** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2667** KEYWORDS: {busy-handler callback} {busy handler}
2668** METHOD: sqlite3
2669**
2670** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2671** that might be invoked with argument P whenever
2672** an attempt is made to access a database table associated with
2673** [database connection] D when another thread
2674** or process has the table locked.
2675** The sqlite3_busy_handler() interface is used to implement
2676** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2677**
2678** ^If the busy callback is NULL, then [SQLITE_BUSY]
2679** is returned immediately upon encountering the lock.  ^If the busy callback
2680** is not NULL, then the callback might be invoked with two arguments.
2681**
2682** ^The first argument to the busy handler is a copy of the void* pointer which
2683** is the third argument to sqlite3_busy_handler().  ^The second argument to
2684** the busy handler callback is the number of times that the busy handler has
2685** been invoked previously for the same locking event.  ^If the
2686** busy callback returns 0, then no additional attempts are made to
2687** access the database and [SQLITE_BUSY] is returned
2688** to the application.
2689** ^If the callback returns non-zero, then another attempt
2690** is made to access the database and the cycle repeats.
2691**
2692** The presence of a busy handler does not guarantee that it will be invoked
2693** when there is lock contention. ^If SQLite determines that invoking the busy
2694** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2695** to the application instead of invoking the
2696** busy handler.
2697** Consider a scenario where one process is holding a read lock that
2698** it is trying to promote to a reserved lock and
2699** a second process is holding a reserved lock that it is trying
2700** to promote to an exclusive lock.  The first process cannot proceed
2701** because it is blocked by the second and the second process cannot
2702** proceed because it is blocked by the first.  If both processes
2703** invoke the busy handlers, neither will make any progress.  Therefore,
2704** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2705** will induce the first process to release its read lock and allow
2706** the second process to proceed.
2707**
2708** ^The default busy callback is NULL.
2709**
2710** ^(There can only be a single busy handler defined for each
2711** [database connection].  Setting a new busy handler clears any
2712** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
2713** or evaluating [PRAGMA busy_timeout=N] will change the
2714** busy handler and thus clear any previously set busy handler.
2715**
2716** The busy callback should not take any actions which modify the
2717** database connection that invoked the busy handler.  In other words,
2718** the busy handler is not reentrant.  Any such actions
2719** result in undefined behavior.
2720**
2721** A busy handler must not close the database connection
2722** or [prepared statement] that invoked the busy handler.
2723*/
2724int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
2725
2726/*
2727** CAPI3REF: Set A Busy Timeout
2728** METHOD: sqlite3
2729**
2730** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2731** for a specified amount of time when a table is locked.  ^The handler
2732** will sleep multiple times until at least "ms" milliseconds of sleeping
2733** have accumulated.  ^After at least "ms" milliseconds of sleeping,
2734** the handler returns 0 which causes [sqlite3_step()] to return
2735** [SQLITE_BUSY].
2736**
2737** ^Calling this routine with an argument less than or equal to zero
2738** turns off all busy handlers.
2739**
2740** ^(There can only be a single busy handler for a particular
2741** [database connection] at any given moment.  If another busy handler
2742** was defined  (using [sqlite3_busy_handler()]) prior to calling
2743** this routine, that other busy handler is cleared.)^
2744**
2745** See also:  [PRAGMA busy_timeout]
2746*/
2747int sqlite3_busy_timeout(sqlite3*, int ms);
2748
2749/*
2750** CAPI3REF: Convenience Routines For Running Queries
2751** METHOD: sqlite3
2752**
2753** This is a legacy interface that is preserved for backwards compatibility.
2754** Use of this interface is not recommended.
2755**
2756** Definition: A <b>result table</b> is memory data structure created by the
2757** [sqlite3_get_table()] interface.  A result table records the
2758** complete query results from one or more queries.
2759**
2760** The table conceptually has a number of rows and columns.  But
2761** these numbers are not part of the result table itself.  These
2762** numbers are obtained separately.  Let N be the number of rows
2763** and M be the number of columns.
2764**
2765** A result table is an array of pointers to zero-terminated UTF-8 strings.
2766** There are (N+1)*M elements in the array.  The first M pointers point
2767** to zero-terminated strings that  contain the names of the columns.
2768** The remaining entries all point to query results.  NULL values result
2769** in NULL pointers.  All other values are in their UTF-8 zero-terminated
2770** string representation as returned by [sqlite3_column_text()].
2771**
2772** A result table might consist of one or more memory allocations.
2773** It is not safe to pass a result table directly to [sqlite3_free()].
2774** A result table should be deallocated using [sqlite3_free_table()].
2775**
2776** ^(As an example of the result table format, suppose a query result
2777** is as follows:
2778**
2779** <blockquote><pre>
2780**        Name        | Age
2781**        -----------------------
2782**        Alice       | 43
2783**        Bob         | 28
2784**        Cindy       | 21
2785** </pre></blockquote>
2786**
2787** There are two columns (M==2) and three rows (N==3).  Thus the
2788** result table has 8 entries.  Suppose the result table is stored
2789** in an array named azResult.  Then azResult holds this content:
2790**
2791** <blockquote><pre>
2792**        azResult&#91;0] = "Name";
2793**        azResult&#91;1] = "Age";
2794**        azResult&#91;2] = "Alice";
2795**        azResult&#91;3] = "43";
2796**        azResult&#91;4] = "Bob";
2797**        azResult&#91;5] = "28";
2798**        azResult&#91;6] = "Cindy";
2799**        azResult&#91;7] = "21";
2800** </pre></blockquote>)^
2801**
2802** ^The sqlite3_get_table() function evaluates one or more
2803** semicolon-separated SQL statements in the zero-terminated UTF-8
2804** string of its 2nd parameter and returns a result table to the
2805** pointer given in its 3rd parameter.
2806**
2807** After the application has finished with the result from sqlite3_get_table(),
2808** it must pass the result table pointer to sqlite3_free_table() in order to
2809** release the memory that was malloced.  Because of the way the
2810** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2811** function must not try to call [sqlite3_free()] directly.  Only
2812** [sqlite3_free_table()] is able to release the memory properly and safely.
2813**
2814** The sqlite3_get_table() interface is implemented as a wrapper around
2815** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
2816** to any internal data structures of SQLite.  It uses only the public
2817** interface defined here.  As a consequence, errors that occur in the
2818** wrapper layer outside of the internal [sqlite3_exec()] call are not
2819** reflected in subsequent calls to [sqlite3_errcode()] or
2820** [sqlite3_errmsg()].
2821*/
2822int sqlite3_get_table(
2823  sqlite3 *db,          /* An open database */
2824  const char *zSql,     /* SQL to be evaluated */
2825  char ***pazResult,    /* Results of the query */
2826  int *pnRow,           /* Number of result rows written here */
2827  int *pnColumn,        /* Number of result columns written here */
2828  char **pzErrmsg       /* Error msg written here */
2829);
2830void sqlite3_free_table(char **result);
2831
2832/*
2833** CAPI3REF: Formatted String Printing Functions
2834**
2835** These routines are work-alikes of the "printf()" family of functions
2836** from the standard C library.
2837** These routines understand most of the common formatting options from
2838** the standard library printf()
2839** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
2840** See the [built-in printf()] documentation for details.
2841**
2842** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2843** results into memory obtained from [sqlite3_malloc64()].
2844** The strings returned by these two routines should be
2845** released by [sqlite3_free()].  ^Both routines return a
2846** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
2847** memory to hold the resulting string.
2848**
2849** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2850** the standard C library.  The result is written into the
2851** buffer supplied as the second parameter whose size is given by
2852** the first parameter. Note that the order of the
2853** first two parameters is reversed from snprintf().)^  This is an
2854** historical accident that cannot be fixed without breaking
2855** backwards compatibility.  ^(Note also that sqlite3_snprintf()
2856** returns a pointer to its buffer instead of the number of
2857** characters actually written into the buffer.)^  We admit that
2858** the number of characters written would be a more useful return
2859** value but we cannot change the implementation of sqlite3_snprintf()
2860** now without breaking compatibility.
2861**
2862** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2863** guarantees that the buffer is always zero-terminated.  ^The first
2864** parameter "n" is the total size of the buffer, including space for
2865** the zero terminator.  So the longest string that can be completely
2866** written will be n-1 characters.
2867**
2868** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2869**
2870** See also:  [built-in printf()], [printf() SQL function]
2871*/
2872char *sqlite3_mprintf(const char*,...);
2873char *sqlite3_vmprintf(const char*, va_list);
2874char *sqlite3_snprintf(int,char*,const char*, ...);
2875char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2876
2877/*
2878** CAPI3REF: Memory Allocation Subsystem
2879**
2880** The SQLite core uses these three routines for all of its own
2881** internal memory allocation needs. "Core" in the previous sentence
2882** does not include operating-system specific [VFS] implementation.  The
2883** Windows VFS uses native malloc() and free() for some operations.
2884**
2885** ^The sqlite3_malloc() routine returns a pointer to a block
2886** of memory at least N bytes in length, where N is the parameter.
2887** ^If sqlite3_malloc() is unable to obtain sufficient free
2888** memory, it returns a NULL pointer.  ^If the parameter N to
2889** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2890** a NULL pointer.
2891**
2892** ^The sqlite3_malloc64(N) routine works just like
2893** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2894** of a signed 32-bit integer.
2895**
2896** ^Calling sqlite3_free() with a pointer previously returned
2897** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2898** that it might be reused.  ^The sqlite3_free() routine is
2899** a no-op if is called with a NULL pointer.  Passing a NULL pointer
2900** to sqlite3_free() is harmless.  After being freed, memory
2901** should neither be read nor written.  Even reading previously freed
2902** memory might result in a segmentation fault or other severe error.
2903** Memory corruption, a segmentation fault, or other severe error
2904** might result if sqlite3_free() is called with a non-NULL pointer that
2905** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2906**
2907** ^The sqlite3_realloc(X,N) interface attempts to resize a
2908** prior memory allocation X to be at least N bytes.
2909** ^If the X parameter to sqlite3_realloc(X,N)
2910** is a NULL pointer then its behavior is identical to calling
2911** sqlite3_malloc(N).
2912** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2913** negative then the behavior is exactly the same as calling
2914** sqlite3_free(X).
2915** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2916** of at least N bytes in size or NULL if insufficient memory is available.
2917** ^If M is the size of the prior allocation, then min(N,M) bytes
2918** of the prior allocation are copied into the beginning of buffer returned
2919** by sqlite3_realloc(X,N) and the prior allocation is freed.
2920** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2921** prior allocation is not freed.
2922**
2923** ^The sqlite3_realloc64(X,N) interfaces works the same as
2924** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2925** of a 32-bit signed integer.
2926**
2927** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2928** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2929** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2930** ^The value returned by sqlite3_msize(X) might be larger than the number
2931** of bytes requested when X was allocated.  ^If X is a NULL pointer then
2932** sqlite3_msize(X) returns zero.  If X points to something that is not
2933** the beginning of memory allocation, or if it points to a formerly
2934** valid memory allocation that has now been freed, then the behavior
2935** of sqlite3_msize(X) is undefined and possibly harmful.
2936**
2937** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2938** sqlite3_malloc64(), and sqlite3_realloc64()
2939** is always aligned to at least an 8 byte boundary, or to a
2940** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2941** option is used.
2942**
2943** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2944** must be either NULL or else pointers obtained from a prior
2945** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2946** not yet been released.
2947**
2948** The application must not read or write any part of
2949** a block of memory after it has been released using
2950** [sqlite3_free()] or [sqlite3_realloc()].
2951*/
2952void *sqlite3_malloc(int);
2953void *sqlite3_malloc64(sqlite3_uint64);
2954void *sqlite3_realloc(void*, int);
2955void *sqlite3_realloc64(void*, sqlite3_uint64);
2956void sqlite3_free(void*);
2957sqlite3_uint64 sqlite3_msize(void*);
2958
2959/*
2960** CAPI3REF: Memory Allocator Statistics
2961**
2962** SQLite provides these two interfaces for reporting on the status
2963** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2964** routines, which form the built-in memory allocation subsystem.
2965**
2966** ^The [sqlite3_memory_used()] routine returns the number of bytes
2967** of memory currently outstanding (malloced but not freed).
2968** ^The [sqlite3_memory_highwater()] routine returns the maximum
2969** value of [sqlite3_memory_used()] since the high-water mark
2970** was last reset.  ^The values returned by [sqlite3_memory_used()] and
2971** [sqlite3_memory_highwater()] include any overhead
2972** added by SQLite in its implementation of [sqlite3_malloc()],
2973** but not overhead added by the any underlying system library
2974** routines that [sqlite3_malloc()] may call.
2975**
2976** ^The memory high-water mark is reset to the current value of
2977** [sqlite3_memory_used()] if and only if the parameter to
2978** [sqlite3_memory_highwater()] is true.  ^The value returned
2979** by [sqlite3_memory_highwater(1)] is the high-water mark
2980** prior to the reset.
2981*/
2982sqlite3_int64 sqlite3_memory_used(void);
2983sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2984
2985/*
2986** CAPI3REF: Pseudo-Random Number Generator
2987**
2988** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2989** select random [ROWID | ROWIDs] when inserting new records into a table that
2990** already uses the largest possible [ROWID].  The PRNG is also used for
2991** the built-in random() and randomblob() SQL functions.  This interface allows
2992** applications to access the same PRNG for other purposes.
2993**
2994** ^A call to this routine stores N bytes of randomness into buffer P.
2995** ^The P parameter can be a NULL pointer.
2996**
2997** ^If this routine has not been previously called or if the previous
2998** call had N less than one or a NULL pointer for P, then the PRNG is
2999** seeded using randomness obtained from the xRandomness method of
3000** the default [sqlite3_vfs] object.
3001** ^If the previous call to this routine had an N of 1 or more and a
3002** non-NULL P then the pseudo-randomness is generated
3003** internally and without recourse to the [sqlite3_vfs] xRandomness
3004** method.
3005*/
3006void sqlite3_randomness(int N, void *P);
3007
3008/*
3009** CAPI3REF: Compile-Time Authorization Callbacks
3010** METHOD: sqlite3
3011** KEYWORDS: {authorizer callback}
3012**
3013** ^This routine registers an authorizer callback with a particular
3014** [database connection], supplied in the first argument.
3015** ^The authorizer callback is invoked as SQL statements are being compiled
3016** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
3017** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
3018** and [sqlite3_prepare16_v3()].  ^At various
3019** points during the compilation process, as logic is being created
3020** to perform various actions, the authorizer callback is invoked to
3021** see if those actions are allowed.  ^The authorizer callback should
3022** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
3023** specific action but allow the SQL statement to continue to be
3024** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
3025** rejected with an error.  ^If the authorizer callback returns
3026** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
3027** then the [sqlite3_prepare_v2()] or equivalent call that triggered
3028** the authorizer will fail with an error message.
3029**
3030** When the callback returns [SQLITE_OK], that means the operation
3031** requested is ok.  ^When the callback returns [SQLITE_DENY], the
3032** [sqlite3_prepare_v2()] or equivalent call that triggered the
3033** authorizer will fail with an error message explaining that
3034** access is denied.
3035**
3036** ^The first parameter to the authorizer callback is a copy of the third
3037** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
3038** to the callback is an integer [SQLITE_COPY | action code] that specifies
3039** the particular action to be authorized. ^The third through sixth parameters
3040** to the callback are either NULL pointers or zero-terminated strings
3041** that contain additional details about the action to be authorized.
3042** Applications must always be prepared to encounter a NULL pointer in any
3043** of the third through the sixth parameters of the authorization callback.
3044**
3045** ^If the action code is [SQLITE_READ]
3046** and the callback returns [SQLITE_IGNORE] then the
3047** [prepared statement] statement is constructed to substitute
3048** a NULL value in place of the table column that would have
3049** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
3050** return can be used to deny an untrusted user access to individual
3051** columns of a table.
3052** ^When a table is referenced by a [SELECT] but no column values are
3053** extracted from that table (for example in a query like
3054** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
3055** is invoked once for that table with a column name that is an empty string.
3056** ^If the action code is [SQLITE_DELETE] and the callback returns
3057** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
3058** [truncate optimization] is disabled and all rows are deleted individually.
3059**
3060** An authorizer is used when [sqlite3_prepare | preparing]
3061** SQL statements from an untrusted source, to ensure that the SQL statements
3062** do not try to access data they are not allowed to see, or that they do not
3063** try to execute malicious statements that damage the database.  For
3064** example, an application may allow a user to enter arbitrary
3065** SQL queries for evaluation by a database.  But the application does
3066** not want the user to be able to make arbitrary changes to the
3067** database.  An authorizer could then be put in place while the
3068** user-entered SQL is being [sqlite3_prepare | prepared] that
3069** disallows everything except [SELECT] statements.
3070**
3071** Applications that need to process SQL from untrusted sources
3072** might also consider lowering resource limits using [sqlite3_limit()]
3073** and limiting database size using the [max_page_count] [PRAGMA]
3074** in addition to using an authorizer.
3075**
3076** ^(Only a single authorizer can be in place on a database connection
3077** at a time.  Each call to sqlite3_set_authorizer overrides the
3078** previous call.)^  ^Disable the authorizer by installing a NULL callback.
3079** The authorizer is disabled by default.
3080**
3081** The authorizer callback must not do anything that will modify
3082** the database connection that invoked the authorizer callback.
3083** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3084** database connections for the meaning of "modify" in this paragraph.
3085**
3086** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
3087** statement might be re-prepared during [sqlite3_step()] due to a
3088** schema change.  Hence, the application should ensure that the
3089** correct authorizer callback remains in place during the [sqlite3_step()].
3090**
3091** ^Note that the authorizer callback is invoked only during
3092** [sqlite3_prepare()] or its variants.  Authorization is not
3093** performed during statement evaluation in [sqlite3_step()], unless
3094** as stated in the previous paragraph, sqlite3_step() invokes
3095** sqlite3_prepare_v2() to reprepare a statement after a schema change.
3096*/
3097int sqlite3_set_authorizer(
3098  sqlite3*,
3099  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
3100  void *pUserData
3101);
3102
3103/*
3104** CAPI3REF: Authorizer Return Codes
3105**
3106** The [sqlite3_set_authorizer | authorizer callback function] must
3107** return either [SQLITE_OK] or one of these two constants in order
3108** to signal SQLite whether or not the action is permitted.  See the
3109** [sqlite3_set_authorizer | authorizer documentation] for additional
3110** information.
3111**
3112** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
3113** returned from the [sqlite3_vtab_on_conflict()] interface.
3114*/
3115#define SQLITE_DENY   1   /* Abort the SQL statement with an error */
3116#define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
3117
3118/*
3119** CAPI3REF: Authorizer Action Codes
3120**
3121** The [sqlite3_set_authorizer()] interface registers a callback function
3122** that is invoked to authorize certain SQL statement actions.  The
3123** second parameter to the callback is an integer code that specifies
3124** what action is being authorized.  These are the integer action codes that
3125** the authorizer callback may be passed.
3126**
3127** These action code values signify what kind of operation is to be
3128** authorized.  The 3rd and 4th parameters to the authorization
3129** callback function will be parameters or NULL depending on which of these
3130** codes is used as the second parameter.  ^(The 5th parameter to the
3131** authorizer callback is the name of the database ("main", "temp",
3132** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
3133** is the name of the inner-most trigger or view that is responsible for
3134** the access attempt or NULL if this access attempt is directly from
3135** top-level SQL code.
3136*/
3137/******************************************* 3rd ************ 4th ***********/
3138#define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
3139#define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
3140#define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
3141#define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
3142#define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
3143#define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
3144#define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
3145#define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
3146#define SQLITE_DELETE                9   /* Table Name      NULL            */
3147#define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
3148#define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
3149#define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
3150#define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
3151#define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
3152#define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
3153#define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
3154#define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
3155#define SQLITE_INSERT               18   /* Table Name      NULL            */
3156#define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
3157#define SQLITE_READ                 20   /* Table Name      Column Name     */
3158#define SQLITE_SELECT               21   /* NULL            NULL            */
3159#define SQLITE_TRANSACTION          22   /* Operation       NULL            */
3160#define SQLITE_UPDATE               23   /* Table Name      Column Name     */
3161#define SQLITE_ATTACH               24   /* Filename        NULL            */
3162#define SQLITE_DETACH               25   /* Database Name   NULL            */
3163#define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
3164#define SQLITE_REINDEX              27   /* Index Name      NULL            */
3165#define SQLITE_ANALYZE              28   /* Table Name      NULL            */
3166#define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
3167#define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
3168#define SQLITE_FUNCTION             31   /* NULL            Function Name   */
3169#define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
3170#define SQLITE_COPY                  0   /* No longer used */
3171#define SQLITE_RECURSIVE            33   /* NULL            NULL            */
3172
3173/*
3174** CAPI3REF: Tracing And Profiling Functions
3175** METHOD: sqlite3
3176**
3177** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
3178** instead of the routines described here.
3179**
3180** These routines register callback functions that can be used for
3181** tracing and profiling the execution of SQL statements.
3182**
3183** ^The callback function registered by sqlite3_trace() is invoked at
3184** various times when an SQL statement is being run by [sqlite3_step()].
3185** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
3186** SQL statement text as the statement first begins executing.
3187** ^(Additional sqlite3_trace() callbacks might occur
3188** as each triggered subprogram is entered.  The callbacks for triggers
3189** contain a UTF-8 SQL comment that identifies the trigger.)^
3190**
3191** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
3192** the length of [bound parameter] expansion in the output of sqlite3_trace().
3193**
3194** ^The callback function registered by sqlite3_profile() is invoked
3195** as each SQL statement finishes.  ^The profile callback contains
3196** the original statement text and an estimate of wall-clock time
3197** of how long that statement took to run.  ^The profile callback
3198** time is in units of nanoseconds, however the current implementation
3199** is only capable of millisecond resolution so the six least significant
3200** digits in the time are meaningless.  Future versions of SQLite
3201** might provide greater resolution on the profiler callback.  Invoking
3202** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the
3203** profile callback.
3204*/
3205SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
3206   void(*xTrace)(void*,const char*), void*);
3207SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
3208   void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
3209
3210/*
3211** CAPI3REF: SQL Trace Event Codes
3212** KEYWORDS: SQLITE_TRACE
3213**
3214** These constants identify classes of events that can be monitored
3215** using the [sqlite3_trace_v2()] tracing logic.  The M argument
3216** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
3217** the following constants.  ^The first argument to the trace callback
3218** is one of the following constants.
3219**
3220** New tracing constants may be added in future releases.
3221**
3222** ^A trace callback has four arguments: xCallback(T,C,P,X).
3223** ^The T argument is one of the integer type codes above.
3224** ^The C argument is a copy of the context pointer passed in as the
3225** fourth argument to [sqlite3_trace_v2()].
3226** The P and X arguments are pointers whose meanings depend on T.
3227**
3228** <dl>
3229** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
3230** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
3231** first begins running and possibly at other times during the
3232** execution of the prepared statement, such as at the start of each
3233** trigger subprogram. ^The P argument is a pointer to the
3234** [prepared statement]. ^The X argument is a pointer to a string which
3235** is the unexpanded SQL text of the prepared statement or an SQL comment
3236** that indicates the invocation of a trigger.  ^The callback can compute
3237** the same text that would have been returned by the legacy [sqlite3_trace()]
3238** interface by using the X argument when X begins with "--" and invoking
3239** [sqlite3_expanded_sql(P)] otherwise.
3240**
3241** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
3242** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
3243** information as is provided by the [sqlite3_profile()] callback.
3244** ^The P argument is a pointer to the [prepared statement] and the
3245** X argument points to a 64-bit integer which is the estimated of
3246** the number of nanosecond that the prepared statement took to run.
3247** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
3248**
3249** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
3250** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
3251** statement generates a single row of result.
3252** ^The P argument is a pointer to the [prepared statement] and the
3253** X argument is unused.
3254**
3255** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
3256** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
3257** connection closes.
3258** ^The P argument is a pointer to the [database connection] object
3259** and the X argument is unused.
3260** </dl>
3261*/
3262#define SQLITE_TRACE_STMT       0x01
3263#define SQLITE_TRACE_PROFILE    0x02
3264#define SQLITE_TRACE_ROW        0x04
3265#define SQLITE_TRACE_CLOSE      0x08
3266
3267/*
3268** CAPI3REF: SQL Trace Hook
3269** METHOD: sqlite3
3270**
3271** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
3272** function X against [database connection] D, using property mask M
3273** and context pointer P.  ^If the X callback is
3274** NULL or if the M mask is zero, then tracing is disabled.  The
3275** M argument should be the bitwise OR-ed combination of
3276** zero or more [SQLITE_TRACE] constants.
3277**
3278** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides
3279** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2().
3280**
3281** ^The X callback is invoked whenever any of the events identified by
3282** mask M occur.  ^The integer return value from the callback is currently
3283** ignored, though this may change in future releases.  Callback
3284** implementations should return zero to ensure future compatibility.
3285**
3286** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
3287** ^The T argument is one of the [SQLITE_TRACE]
3288** constants to indicate why the callback was invoked.
3289** ^The C argument is a copy of the context pointer.
3290** The P and X arguments are pointers whose meanings depend on T.
3291**
3292** The sqlite3_trace_v2() interface is intended to replace the legacy
3293** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
3294** are deprecated.
3295*/
3296int sqlite3_trace_v2(
3297  sqlite3*,
3298  unsigned uMask,
3299  int(*xCallback)(unsigned,void*,void*,void*),
3300  void *pCtx
3301);
3302
3303/*
3304** CAPI3REF: Query Progress Callbacks
3305** METHOD: sqlite3
3306**
3307** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
3308** function X to be invoked periodically during long running calls to
3309** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
3310** database connection D.  An example use for this
3311** interface is to keep a GUI updated during a large query.
3312**
3313** ^The parameter P is passed through as the only parameter to the
3314** callback function X.  ^The parameter N is the approximate number of
3315** [virtual machine instructions] that are evaluated between successive
3316** invocations of the callback X.  ^If N is less than one then the progress
3317** handler is disabled.
3318**
3319** ^Only a single progress handler may be defined at one time per
3320** [database connection]; setting a new progress handler cancels the
3321** old one.  ^Setting parameter X to NULL disables the progress handler.
3322** ^The progress handler is also disabled by setting N to a value less
3323** than 1.
3324**
3325** ^If the progress callback returns non-zero, the operation is
3326** interrupted.  This feature can be used to implement a
3327** "Cancel" button on a GUI progress dialog box.
3328**
3329** The progress handler callback must not do anything that will modify
3330** the database connection that invoked the progress handler.
3331** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3332** database connections for the meaning of "modify" in this paragraph.
3333**
3334*/
3335void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
3336
3337/*
3338** CAPI3REF: Opening A New Database Connection
3339** CONSTRUCTOR: sqlite3
3340**
3341** ^These routines open an SQLite database file as specified by the
3342** filename argument. ^The filename argument is interpreted as UTF-8 for
3343** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
3344** order for sqlite3_open16(). ^(A [database connection] handle is usually
3345** returned in *ppDb, even if an error occurs.  The only exception is that
3346** if SQLite is unable to allocate memory to hold the [sqlite3] object,
3347** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
3348** object.)^ ^(If the database is opened (and/or created) successfully, then
3349** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
3350** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
3351** an English language description of the error following a failure of any
3352** of the sqlite3_open() routines.
3353**
3354** ^The default encoding will be UTF-8 for databases created using
3355** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
3356** created using sqlite3_open16() will be UTF-16 in the native byte order.
3357**
3358** Whether or not an error occurs when it is opened, resources
3359** associated with the [database connection] handle should be released by
3360** passing it to [sqlite3_close()] when it is no longer required.
3361**
3362** The sqlite3_open_v2() interface works like sqlite3_open()
3363** except that it accepts two additional parameters for additional control
3364** over the new database connection.  ^(The flags parameter to
3365** sqlite3_open_v2() must include, at a minimum, one of the following
3366** three flag combinations:)^
3367**
3368** <dl>
3369** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
3370** <dd>The database is opened in read-only mode.  If the database does not
3371** already exist, an error is returned.</dd>)^
3372**
3373** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
3374** <dd>The database is opened for reading and writing if possible, or reading
3375** only if the file is write protected by the operating system.  In either
3376** case the database must already exist, otherwise an error is returned.</dd>)^
3377**
3378** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
3379** <dd>The database is opened for reading and writing, and is created if
3380** it does not already exist. This is the behavior that is always used for
3381** sqlite3_open() and sqlite3_open16().</dd>)^
3382** </dl>
3383**
3384** In addition to the required flags, the following optional flags are
3385** also supported:
3386**
3387** <dl>
3388** ^(<dt>[SQLITE_OPEN_URI]</dt>
3389** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^
3390**
3391** ^(<dt>[SQLITE_OPEN_MEMORY]</dt>
3392** <dd>The database will be opened as an in-memory database.  The database
3393** is named by the "filename" argument for the purposes of cache-sharing,
3394** if shared cache mode is enabled, but the "filename" is otherwise ignored.
3395** </dd>)^
3396**
3397** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt>
3398** <dd>The new database connection will use the "multi-thread"
3399** [threading mode].)^  This means that separate threads are allowed
3400** to use SQLite at the same time, as long as each thread is using
3401** a different [database connection].
3402**
3403** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt>
3404** <dd>The new database connection will use the "serialized"
3405** [threading mode].)^  This means the multiple threads can safely
3406** attempt to use the same database connection at the same time.
3407** (Mutexes will block any actual concurrency, but in this mode
3408** there is no harm in trying.)
3409**
3410** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt>
3411** <dd>The database is opened [shared cache] enabled, overriding
3412** the default shared cache setting provided by
3413** [sqlite3_enable_shared_cache()].)^
3414**
3415** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt>
3416** <dd>The database is opened [shared cache] disabled, overriding
3417** the default shared cache setting provided by
3418** [sqlite3_enable_shared_cache()].)^
3419**
3420** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt>
3421** <dd>The database filename is not allowed to be a symbolic link</dd>
3422**
3423** [[OPEN_EXCLUSIVE]] ^(<dt>[SQLITE_OPEN_EXCLUSIVE]</dt>
3424** <dd>This flag causes the open to fail if the database file already
3425** exists.  The open will only be success if this flag is used in combination
3426** with the SQLITE_OPEN_CREATE and SQLITE_OPEN_READWRITE flags and if
3427** the file does not previously exist.</dd>
3428** </dl>)^
3429**
3430** If the 3rd parameter to sqlite3_open_v2() is not one of the
3431** required combinations shown above optionally combined with other
3432** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
3433** then the behavior is undefined.
3434**
3435** ^The fourth parameter to sqlite3_open_v2() is the name of the
3436** [sqlite3_vfs] object that defines the operating system interface that
3437** the new database connection should use.  ^If the fourth parameter is
3438** a NULL pointer then the default [sqlite3_vfs] object is used.
3439**
3440** ^If the filename is ":memory:", then a private, temporary in-memory database
3441** is created for the connection.  ^This in-memory database will vanish when
3442** the database connection is closed.  Future versions of SQLite might
3443** make use of additional special filenames that begin with the ":" character.
3444** It is recommended that when a database filename actually does begin with
3445** a ":" character you should prefix the filename with a pathname such as
3446** "./" to avoid ambiguity.
3447**
3448** ^If the filename is an empty string, then a private, temporary
3449** on-disk database will be created.  ^This private database will be
3450** automatically deleted as soon as the database connection is closed.
3451**
3452** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
3453**
3454** ^If [URI filename] interpretation is enabled, and the filename argument
3455** begins with "file:", then the filename is interpreted as a URI. ^URI
3456** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
3457** set in the third argument to sqlite3_open_v2(), or if it has
3458** been enabled globally using the [SQLITE_CONFIG_URI] option with the
3459** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
3460** URI filename interpretation is turned off
3461** by default, but future releases of SQLite might enable URI filename
3462** interpretation by default.  See "[URI filenames]" for additional
3463** information.
3464**
3465** URI filenames are parsed according to RFC 3986. ^If the URI contains an
3466** authority, then it must be either an empty string or the string
3467** "localhost". ^If the authority is not an empty string or "localhost", an
3468** error is returned to the caller. ^The fragment component of a URI, if
3469** present, is ignored.
3470**
3471** ^SQLite uses the path component of the URI as the name of the disk file
3472** which contains the database. ^If the path begins with a '/' character,
3473** then it is interpreted as an absolute path. ^If the path does not begin
3474** with a '/' (meaning that the authority section is omitted from the URI)
3475** then the path is interpreted as a relative path.
3476** ^(On windows, the first component of an absolute path
3477** is a drive specification (e.g. "C:").)^
3478**
3479** [[core URI query parameters]]
3480** The query component of a URI may contain parameters that are interpreted
3481** either by SQLite itself, or by a [VFS | custom VFS implementation].
3482** SQLite and its built-in [VFSes] interpret the
3483** following query parameters:
3484**
3485** <ul>
3486**   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
3487**     a VFS object that provides the operating system interface that should
3488**     be used to access the database file on disk. ^If this option is set to
3489**     an empty string the default VFS object is used. ^Specifying an unknown
3490**     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
3491**     present, then the VFS specified by the option takes precedence over
3492**     the value passed as the fourth parameter to sqlite3_open_v2().
3493**
3494**   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
3495**     "rwc", or "memory". Attempting to set it to any other value is
3496**     an error)^.
3497**     ^If "ro" is specified, then the database is opened for read-only
3498**     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
3499**     third argument to sqlite3_open_v2(). ^If the mode option is set to
3500**     "rw", then the database is opened for read-write (but not create)
3501**     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
3502**     been set. ^Value "rwc" is equivalent to setting both
3503**     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
3504**     set to "memory" then a pure [in-memory database] that never reads
3505**     or writes from disk is used. ^It is an error to specify a value for
3506**     the mode parameter that is less restrictive than that specified by
3507**     the flags passed in the third parameter to sqlite3_open_v2().
3508**
3509**   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
3510**     "private". ^Setting it to "shared" is equivalent to setting the
3511**     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
3512**     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
3513**     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
3514**     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
3515**     a URI filename, its value overrides any behavior requested by setting
3516**     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
3517**
3518**  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
3519**     [powersafe overwrite] property does or does not apply to the
3520**     storage media on which the database file resides.
3521**
3522**  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
3523**     which if set disables file locking in rollback journal modes.  This
3524**     is useful for accessing a database on a filesystem that does not
3525**     support locking.  Caution:  Database corruption might result if two
3526**     or more processes write to the same database and any one of those
3527**     processes uses nolock=1.
3528**
3529**  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
3530**     parameter that indicates that the database file is stored on
3531**     read-only media.  ^When immutable is set, SQLite assumes that the
3532**     database file cannot be changed, even by a process with higher
3533**     privilege, and so the database is opened read-only and all locking
3534**     and change detection is disabled.  Caution: Setting the immutable
3535**     property on a database file that does in fact change can result
3536**     in incorrect query results and/or [SQLITE_CORRUPT] errors.
3537**     See also: [SQLITE_IOCAP_IMMUTABLE].
3538**
3539** </ul>
3540**
3541** ^Specifying an unknown parameter in the query component of a URI is not an
3542** error.  Future versions of SQLite might understand additional query
3543** parameters.  See "[query parameters with special meaning to SQLite]" for
3544** additional information.
3545**
3546** [[URI filename examples]] <h3>URI filename examples</h3>
3547**
3548** <table border="1" align=center cellpadding=5>
3549** <tr><th> URI filenames <th> Results
3550** <tr><td> file:data.db <td>
3551**          Open the file "data.db" in the current directory.
3552** <tr><td> file:/home/fred/data.db<br>
3553**          file:///home/fred/data.db <br>
3554**          file://localhost/home/fred/data.db <br> <td>
3555**          Open the database file "/home/fred/data.db".
3556** <tr><td> file://darkstar/home/fred/data.db <td>
3557**          An error. "darkstar" is not a recognized authority.
3558** <tr><td style="white-space:nowrap">
3559**          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
3560**     <td> Windows only: Open the file "data.db" on fred's desktop on drive
3561**          C:. Note that the %20 escaping in this example is not strictly
3562**          necessary - space characters can be used literally
3563**          in URI filenames.
3564** <tr><td> file:data.db?mode=ro&cache=private <td>
3565**          Open file "data.db" in the current directory for read-only access.
3566**          Regardless of whether or not shared-cache mode is enabled by
3567**          default, use a private cache.
3568** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
3569**          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
3570**          that uses dot-files in place of posix advisory locking.
3571** <tr><td> file:data.db?mode=readonly <td>
3572**          An error. "readonly" is not a valid option for the "mode" parameter.
3573**          Use "ro" instead:  "file:data.db?mode=ro".
3574** </table>
3575**
3576** ^URI hexadecimal escape sequences (%HH) are supported within the path and
3577** query components of a URI. A hexadecimal escape sequence consists of a
3578** percent sign - "%" - followed by exactly two hexadecimal digits
3579** specifying an octet value. ^Before the path or query components of a
3580** URI filename are interpreted, they are encoded using UTF-8 and all
3581** hexadecimal escape sequences replaced by a single byte containing the
3582** corresponding octet. If this process generates an invalid UTF-8 encoding,
3583** the results are undefined.
3584**
3585** <b>Note to Windows users:</b>  The encoding used for the filename argument
3586** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
3587** codepage is currently defined.  Filenames containing international
3588** characters must be converted to UTF-8 prior to passing them into
3589** sqlite3_open() or sqlite3_open_v2().
3590**
3591** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
3592** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
3593** features that require the use of temporary files may fail.
3594**
3595** See also: [sqlite3_temp_directory]
3596*/
3597int sqlite3_open(
3598  const char *filename,   /* Database filename (UTF-8) */
3599  sqlite3 **ppDb          /* OUT: SQLite db handle */
3600);
3601int sqlite3_open16(
3602  const void *filename,   /* Database filename (UTF-16) */
3603  sqlite3 **ppDb          /* OUT: SQLite db handle */
3604);
3605int sqlite3_open_v2(
3606  const char *filename,   /* Database filename (UTF-8) */
3607  sqlite3 **ppDb,         /* OUT: SQLite db handle */
3608  int flags,              /* Flags */
3609  const char *zVfs        /* Name of VFS module to use */
3610);
3611
3612/*
3613** CAPI3REF: Obtain Values For URI Parameters
3614**
3615** These are utility routines, useful to [VFS|custom VFS implementations],
3616** that check if a database file was a URI that contained a specific query
3617** parameter, and if so obtains the value of that query parameter.
3618**
3619** The first parameter to these interfaces (hereafter referred to
3620** as F) must be one of:
3621** <ul>
3622** <li> A database filename pointer created by the SQLite core and
3623** passed into the xOpen() method of a VFS implemention, or
3624** <li> A filename obtained from [sqlite3_db_filename()], or
3625** <li> A new filename constructed using [sqlite3_create_filename()].
3626** </ul>
3627** If the F parameter is not one of the above, then the behavior is
3628** undefined and probably undesirable.  Older versions of SQLite were
3629** more tolerant of invalid F parameters than newer versions.
3630**
3631** If F is a suitable filename (as described in the previous paragraph)
3632** and if P is the name of the query parameter, then
3633** sqlite3_uri_parameter(F,P) returns the value of the P
3634** parameter if it exists or a NULL pointer if P does not appear as a
3635** query parameter on F.  If P is a query parameter of F and it
3636** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3637** a pointer to an empty string.
3638**
3639** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3640** parameter and returns true (1) or false (0) according to the value
3641** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3642** value of query parameter P is one of "yes", "true", or "on" in any
3643** case or if the value begins with a non-zero number.  The
3644** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3645** query parameter P is one of "no", "false", or "off" in any case or
3646** if the value begins with a numeric zero.  If P is not a query
3647** parameter on F or if the value of P does not match any of the
3648** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3649**
3650** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3651** 64-bit signed integer and returns that integer, or D if P does not
3652** exist.  If the value of P is something other than an integer, then
3653** zero is returned.
3654**
3655** The sqlite3_uri_key(F,N) returns a pointer to the name (not
3656** the value) of the N-th query parameter for filename F, or a NULL
3657** pointer if N is less than zero or greater than the number of query
3658** parameters minus 1.  The N value is zero-based so N should be 0 to obtain
3659** the name of the first query parameter, 1 for the second parameter, and
3660** so forth.
3661**
3662** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3663** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
3664** is not a database file pathname pointer that the SQLite core passed
3665** into the xOpen VFS method, then the behavior of this routine is undefined
3666** and probably undesirable.
3667**
3668** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F
3669** parameter can also be the name of a rollback journal file or WAL file
3670** in addition to the main database file.  Prior to version 3.31.0, these
3671** routines would only work if F was the name of the main database file.
3672** When the F parameter is the name of the rollback journal or WAL file,
3673** it has access to all the same query parameters as were found on the
3674** main database file.
3675**
3676** See the [URI filename] documentation for additional information.
3677*/
3678const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3679int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3680sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3681const char *sqlite3_uri_key(const char *zFilename, int N);
3682
3683/*
3684** CAPI3REF:  Translate filenames
3685**
3686** These routines are available to [VFS|custom VFS implementations] for
3687** translating filenames between the main database file, the journal file,
3688** and the WAL file.
3689**
3690** If F is the name of an sqlite database file, journal file, or WAL file
3691** passed by the SQLite core into the VFS, then sqlite3_filename_database(F)
3692** returns the name of the corresponding database file.
3693**
3694** If F is the name of an sqlite database file, journal file, or WAL file
3695** passed by the SQLite core into the VFS, or if F is a database filename
3696** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F)
3697** returns the name of the corresponding rollback journal file.
3698**
3699** If F is the name of an sqlite database file, journal file, or WAL file
3700** that was passed by the SQLite core into the VFS, or if F is a database
3701** filename obtained from [sqlite3_db_filename()], then
3702** sqlite3_filename_wal(F) returns the name of the corresponding
3703** WAL file.
3704**
3705** In all of the above, if F is not the name of a database, journal or WAL
3706** filename passed into the VFS from the SQLite core and F is not the
3707** return value from [sqlite3_db_filename()], then the result is
3708** undefined and is likely a memory access violation.
3709*/
3710const char *sqlite3_filename_database(const char*);
3711const char *sqlite3_filename_journal(const char*);
3712const char *sqlite3_filename_wal(const char*);
3713
3714/*
3715** CAPI3REF:  Database File Corresponding To A Journal
3716**
3717** ^If X is the name of a rollback or WAL-mode journal file that is
3718** passed into the xOpen method of [sqlite3_vfs], then
3719** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file]
3720** object that represents the main database file.
3721**
3722** This routine is intended for use in custom [VFS] implementations
3723** only.  It is not a general-purpose interface.
3724** The argument sqlite3_file_object(X) must be a filename pointer that
3725** has been passed into [sqlite3_vfs].xOpen method where the
3726** flags parameter to xOpen contains one of the bits
3727** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL].  Any other use
3728** of this routine results in undefined and probably undesirable
3729** behavior.
3730*/
3731sqlite3_file *sqlite3_database_file_object(const char*);
3732
3733/*
3734** CAPI3REF: Create and Destroy VFS Filenames
3735**
3736** These interfces are provided for use by [VFS shim] implementations and
3737** are not useful outside of that context.
3738**
3739** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of
3740** database filename D with corresponding journal file J and WAL file W and
3741** with N URI parameters key/values pairs in the array P.  The result from
3742** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that
3743** is safe to pass to routines like:
3744** <ul>
3745** <li> [sqlite3_uri_parameter()],
3746** <li> [sqlite3_uri_boolean()],
3747** <li> [sqlite3_uri_int64()],
3748** <li> [sqlite3_uri_key()],
3749** <li> [sqlite3_filename_database()],
3750** <li> [sqlite3_filename_journal()], or
3751** <li> [sqlite3_filename_wal()].
3752** </ul>
3753** If a memory allocation error occurs, sqlite3_create_filename() might
3754** return a NULL pointer.  The memory obtained from sqlite3_create_filename(X)
3755** must be released by a corresponding call to sqlite3_free_filename(Y).
3756**
3757** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array
3758** of 2*N pointers to strings.  Each pair of pointers in this array corresponds
3759** to a key and value for a query parameter.  The P parameter may be a NULL
3760** pointer if N is zero.  None of the 2*N pointers in the P array may be
3761** NULL pointers and key pointers should not be empty strings.
3762** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may
3763** be NULL pointers, though they can be empty strings.
3764**
3765** The sqlite3_free_filename(Y) routine releases a memory allocation
3766** previously obtained from sqlite3_create_filename().  Invoking
3767** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op.
3768**
3769** If the Y parameter to sqlite3_free_filename(Y) is anything other
3770** than a NULL pointer or a pointer previously acquired from
3771** sqlite3_create_filename(), then bad things such as heap
3772** corruption or segfaults may occur. The value Y should not be
3773** used again after sqlite3_free_filename(Y) has been called.  This means
3774** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y,
3775** then the corresponding [sqlite3_module.xClose() method should also be
3776** invoked prior to calling sqlite3_free_filename(Y).
3777*/
3778char *sqlite3_create_filename(
3779  const char *zDatabase,
3780  const char *zJournal,
3781  const char *zWal,
3782  int nParam,
3783  const char **azParam
3784);
3785void sqlite3_free_filename(char*);
3786
3787/*
3788** CAPI3REF: Error Codes And Messages
3789** METHOD: sqlite3
3790**
3791** ^If the most recent sqlite3_* API call associated with
3792** [database connection] D failed, then the sqlite3_errcode(D) interface
3793** returns the numeric [result code] or [extended result code] for that
3794** API call.
3795** ^The sqlite3_extended_errcode()
3796** interface is the same except that it always returns the
3797** [extended result code] even when extended result codes are
3798** disabled.
3799**
3800** The values returned by sqlite3_errcode() and/or
3801** sqlite3_extended_errcode() might change with each API call.
3802** Except, there are some interfaces that are guaranteed to never
3803** change the value of the error code.  The error-code preserving
3804** interfaces are:
3805**
3806** <ul>
3807** <li> sqlite3_errcode()
3808** <li> sqlite3_extended_errcode()
3809** <li> sqlite3_errmsg()
3810** <li> sqlite3_errmsg16()
3811** </ul>
3812**
3813** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3814** text that describes the error, as either UTF-8 or UTF-16 respectively.
3815** ^(Memory to hold the error message string is managed internally.
3816** The application does not need to worry about freeing the result.
3817** However, the error string might be overwritten or deallocated by
3818** subsequent calls to other SQLite interface functions.)^
3819**
3820** ^The sqlite3_errstr() interface returns the English-language text
3821** that describes the [result code], as UTF-8.
3822** ^(Memory to hold the error message string is managed internally
3823** and must not be freed by the application)^.
3824**
3825** When the serialized [threading mode] is in use, it might be the
3826** case that a second error occurs on a separate thread in between
3827** the time of the first error and the call to these interfaces.
3828** When that happens, the second error will be reported since these
3829** interfaces always report the most recent result.  To avoid
3830** this, each thread can obtain exclusive use of the [database connection] D
3831** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3832** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3833** all calls to the interfaces listed here are completed.
3834**
3835** If an interface fails with SQLITE_MISUSE, that means the interface
3836** was invoked incorrectly by the application.  In that case, the
3837** error code and message may or may not be set.
3838*/
3839int sqlite3_errcode(sqlite3 *db);
3840int sqlite3_extended_errcode(sqlite3 *db);
3841const char *sqlite3_errmsg(sqlite3*);
3842const void *sqlite3_errmsg16(sqlite3*);
3843const char *sqlite3_errstr(int);
3844
3845/*
3846** CAPI3REF: Prepared Statement Object
3847** KEYWORDS: {prepared statement} {prepared statements}
3848**
3849** An instance of this object represents a single SQL statement that
3850** has been compiled into binary form and is ready to be evaluated.
3851**
3852** Think of each SQL statement as a separate computer program.  The
3853** original SQL text is source code.  A prepared statement object
3854** is the compiled object code.  All SQL must be converted into a
3855** prepared statement before it can be run.
3856**
3857** The life-cycle of a prepared statement object usually goes like this:
3858**
3859** <ol>
3860** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
3861** <li> Bind values to [parameters] using the sqlite3_bind_*()
3862**      interfaces.
3863** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3864** <li> Reset the prepared statement using [sqlite3_reset()] then go back
3865**      to step 2.  Do this zero or more times.
3866** <li> Destroy the object using [sqlite3_finalize()].
3867** </ol>
3868*/
3869typedef struct sqlite3_stmt sqlite3_stmt;
3870
3871/*
3872** CAPI3REF: Run-time Limits
3873** METHOD: sqlite3
3874**
3875** ^(This interface allows the size of various constructs to be limited
3876** on a connection by connection basis.  The first parameter is the
3877** [database connection] whose limit is to be set or queried.  The
3878** second parameter is one of the [limit categories] that define a
3879** class of constructs to be size limited.  The third parameter is the
3880** new limit for that construct.)^
3881**
3882** ^If the new limit is a negative number, the limit is unchanged.
3883** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3884** [limits | hard upper bound]
3885** set at compile-time by a C preprocessor macro called
3886** [limits | SQLITE_MAX_<i>NAME</i>].
3887** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3888** ^Attempts to increase a limit above its hard upper bound are
3889** silently truncated to the hard upper bound.
3890**
3891** ^Regardless of whether or not the limit was changed, the
3892** [sqlite3_limit()] interface returns the prior value of the limit.
3893** ^Hence, to find the current value of a limit without changing it,
3894** simply invoke this interface with the third parameter set to -1.
3895**
3896** Run-time limits are intended for use in applications that manage
3897** both their own internal database and also databases that are controlled
3898** by untrusted external sources.  An example application might be a
3899** web browser that has its own databases for storing history and
3900** separate databases controlled by JavaScript applications downloaded
3901** off the Internet.  The internal databases can be given the
3902** large, default limits.  Databases managed by external sources can
3903** be given much smaller limits designed to prevent a denial of service
3904** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
3905** interface to further control untrusted SQL.  The size of the database
3906** created by an untrusted script can be contained using the
3907** [max_page_count] [PRAGMA].
3908**
3909** New run-time limit categories may be added in future releases.
3910*/
3911int sqlite3_limit(sqlite3*, int id, int newVal);
3912
3913/*
3914** CAPI3REF: Run-Time Limit Categories
3915** KEYWORDS: {limit category} {*limit categories}
3916**
3917** These constants define various performance limits
3918** that can be lowered at run-time using [sqlite3_limit()].
3919** The synopsis of the meanings of the various limits is shown below.
3920** Additional information is available at [limits | Limits in SQLite].
3921**
3922** <dl>
3923** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3924** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3925**
3926** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3927** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3928**
3929** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3930** <dd>The maximum number of columns in a table definition or in the
3931** result set of a [SELECT] or the maximum number of columns in an index
3932** or in an ORDER BY or GROUP BY clause.</dd>)^
3933**
3934** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3935** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3936**
3937** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3938** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3939**
3940** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3941** <dd>The maximum number of instructions in a virtual machine program
3942** used to implement an SQL statement.  If [sqlite3_prepare_v2()] or
3943** the equivalent tries to allocate space for more than this many opcodes
3944** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
3945**
3946** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3947** <dd>The maximum number of arguments on a function.</dd>)^
3948**
3949** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3950** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3951**
3952** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3953** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3954** <dd>The maximum length of the pattern argument to the [LIKE] or
3955** [GLOB] operators.</dd>)^
3956**
3957** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3958** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3959** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3960**
3961** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3962** <dd>The maximum depth of recursion for triggers.</dd>)^
3963**
3964** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
3965** <dd>The maximum number of auxiliary worker threads that a single
3966** [prepared statement] may start.</dd>)^
3967** </dl>
3968*/
3969#define SQLITE_LIMIT_LENGTH                    0
3970#define SQLITE_LIMIT_SQL_LENGTH                1
3971#define SQLITE_LIMIT_COLUMN                    2
3972#define SQLITE_LIMIT_EXPR_DEPTH                3
3973#define SQLITE_LIMIT_COMPOUND_SELECT           4
3974#define SQLITE_LIMIT_VDBE_OP                   5
3975#define SQLITE_LIMIT_FUNCTION_ARG              6
3976#define SQLITE_LIMIT_ATTACHED                  7
3977#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
3978#define SQLITE_LIMIT_VARIABLE_NUMBER           9
3979#define SQLITE_LIMIT_TRIGGER_DEPTH            10
3980#define SQLITE_LIMIT_WORKER_THREADS           11
3981
3982/*
3983** CAPI3REF: Prepare Flags
3984**
3985** These constants define various flags that can be passed into
3986** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
3987** [sqlite3_prepare16_v3()] interfaces.
3988**
3989** New flags may be added in future releases of SQLite.
3990**
3991** <dl>
3992** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
3993** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
3994** that the prepared statement will be retained for a long time and
3995** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
3996** and [sqlite3_prepare16_v3()] assume that the prepared statement will
3997** be used just once or at most a few times and then destroyed using
3998** [sqlite3_finalize()] relatively soon. The current implementation acts
3999** on this hint by avoiding the use of [lookaside memory] so as not to
4000** deplete the limited store of lookaside memory. Future versions of
4001** SQLite may act on this hint differently.
4002**
4003** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt>
4004** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
4005** to be required for any prepared statement that wanted to use the
4006** [sqlite3_normalized_sql()] interface.  However, the
4007** [sqlite3_normalized_sql()] interface is now available to all
4008** prepared statements, regardless of whether or not they use this
4009** flag.
4010**
4011** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt>
4012** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
4013** to return an error (error code SQLITE_ERROR) if the statement uses
4014** any virtual tables.
4015** </dl>
4016*/
4017#define SQLITE_PREPARE_PERSISTENT              0x01
4018#define SQLITE_PREPARE_NORMALIZE               0x02
4019#define SQLITE_PREPARE_NO_VTAB                 0x04
4020
4021/*
4022** CAPI3REF: Compiling An SQL Statement
4023** KEYWORDS: {SQL statement compiler}
4024** METHOD: sqlite3
4025** CONSTRUCTOR: sqlite3_stmt
4026**
4027** To execute an SQL statement, it must first be compiled into a byte-code
4028** program using one of these routines.  Or, in other words, these routines
4029** are constructors for the [prepared statement] object.
4030**
4031** The preferred routine to use is [sqlite3_prepare_v2()].  The
4032** [sqlite3_prepare()] interface is legacy and should be avoided.
4033** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
4034** for special purposes.
4035**
4036** The use of the UTF-8 interfaces is preferred, as SQLite currently
4037** does all parsing using UTF-8.  The UTF-16 interfaces are provided
4038** as a convenience.  The UTF-16 interfaces work by converting the
4039** input text into UTF-8, then invoking the corresponding UTF-8 interface.
4040**
4041** The first argument, "db", is a [database connection] obtained from a
4042** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
4043** [sqlite3_open16()].  The database connection must not have been closed.
4044**
4045** The second argument, "zSql", is the statement to be compiled, encoded
4046** as either UTF-8 or UTF-16.  The sqlite3_prepare(), sqlite3_prepare_v2(),
4047** and sqlite3_prepare_v3()
4048** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
4049** and sqlite3_prepare16_v3() use UTF-16.
4050**
4051** ^If the nByte argument is negative, then zSql is read up to the
4052** first zero terminator. ^If nByte is positive, then it is the
4053** number of bytes read from zSql.  ^If nByte is zero, then no prepared
4054** statement is generated.
4055** If the caller knows that the supplied string is nul-terminated, then
4056** there is a small performance advantage to passing an nByte parameter that
4057** is the number of bytes in the input string <i>including</i>
4058** the nul-terminator.
4059**
4060** ^If pzTail is not NULL then *pzTail is made to point to the first byte
4061** past the end of the first SQL statement in zSql.  These routines only
4062** compile the first statement in zSql, so *pzTail is left pointing to
4063** what remains uncompiled.
4064**
4065** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
4066** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
4067** to NULL.  ^If the input text contains no SQL (if the input is an empty
4068** string or a comment) then *ppStmt is set to NULL.
4069** The calling procedure is responsible for deleting the compiled
4070** SQL statement using [sqlite3_finalize()] after it has finished with it.
4071** ppStmt may not be NULL.
4072**
4073** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
4074** otherwise an [error code] is returned.
4075**
4076** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
4077** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
4078** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
4079** are retained for backwards compatibility, but their use is discouraged.
4080** ^In the "vX" interfaces, the prepared statement
4081** that is returned (the [sqlite3_stmt] object) contains a copy of the
4082** original SQL text. This causes the [sqlite3_step()] interface to
4083** behave differently in three ways:
4084**
4085** <ol>
4086** <li>
4087** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
4088** always used to do, [sqlite3_step()] will automatically recompile the SQL
4089** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
4090** retries will occur before sqlite3_step() gives up and returns an error.
4091** </li>
4092**
4093** <li>
4094** ^When an error occurs, [sqlite3_step()] will return one of the detailed
4095** [error codes] or [extended error codes].  ^The legacy behavior was that
4096** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
4097** and the application would have to make a second call to [sqlite3_reset()]
4098** in order to find the underlying cause of the problem. With the "v2" prepare
4099** interfaces, the underlying reason for the error is returned immediately.
4100** </li>
4101**
4102** <li>
4103** ^If the specific value bound to a [parameter | host parameter] in the
4104** WHERE clause might influence the choice of query plan for a statement,
4105** then the statement will be automatically recompiled, as if there had been
4106** a schema change, on the first [sqlite3_step()] call following any change
4107** to the [sqlite3_bind_text | bindings] of that [parameter].
4108** ^The specific value of a WHERE-clause [parameter] might influence the
4109** choice of query plan if the parameter is the left-hand side of a [LIKE]
4110** or [GLOB] operator or if the parameter is compared to an indexed column
4111** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled.
4112** </li>
4113** </ol>
4114**
4115** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
4116** the extra prepFlags parameter, which is a bit array consisting of zero or
4117** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags.  ^The
4118** sqlite3_prepare_v2() interface works exactly the same as
4119** sqlite3_prepare_v3() with a zero prepFlags parameter.
4120*/
4121int sqlite3_prepare(
4122  sqlite3 *db,            /* Database handle */
4123  const char *zSql,       /* SQL statement, UTF-8 encoded */
4124  int nByte,              /* Maximum length of zSql in bytes. */
4125  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4126  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
4127);
4128int sqlite3_prepare_v2(
4129  sqlite3 *db,            /* Database handle */
4130  const char *zSql,       /* SQL statement, UTF-8 encoded */
4131  int nByte,              /* Maximum length of zSql in bytes. */
4132  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4133  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
4134);
4135int sqlite3_prepare_v3(
4136  sqlite3 *db,            /* Database handle */
4137  const char *zSql,       /* SQL statement, UTF-8 encoded */
4138  int nByte,              /* Maximum length of zSql in bytes. */
4139  unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
4140  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4141  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
4142);
4143int sqlite3_prepare16(
4144  sqlite3 *db,            /* Database handle */
4145  const void *zSql,       /* SQL statement, UTF-16 encoded */
4146  int nByte,              /* Maximum length of zSql in bytes. */
4147  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4148  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
4149);
4150int sqlite3_prepare16_v2(
4151  sqlite3 *db,            /* Database handle */
4152  const void *zSql,       /* SQL statement, UTF-16 encoded */
4153  int nByte,              /* Maximum length of zSql in bytes. */
4154  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4155  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
4156);
4157int sqlite3_prepare16_v3(
4158  sqlite3 *db,            /* Database handle */
4159  const void *zSql,       /* SQL statement, UTF-16 encoded */
4160  int nByte,              /* Maximum length of zSql in bytes. */
4161  unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
4162  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4163  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
4164);
4165
4166/*
4167** CAPI3REF: Retrieving Statement SQL
4168** METHOD: sqlite3_stmt
4169**
4170** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
4171** SQL text used to create [prepared statement] P if P was
4172** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
4173** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4174** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
4175** string containing the SQL text of prepared statement P with
4176** [bound parameters] expanded.
4177** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
4178** string containing the normalized SQL text of prepared statement P.  The
4179** semantics used to normalize a SQL statement are unspecified and subject
4180** to change.  At a minimum, literal values will be replaced with suitable
4181** placeholders.
4182**
4183** ^(For example, if a prepared statement is created using the SQL
4184** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
4185** and parameter :xyz is unbound, then sqlite3_sql() will return
4186** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
4187** will return "SELECT 2345,NULL".)^
4188**
4189** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
4190** is available to hold the result, or if the result would exceed the
4191** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
4192**
4193** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
4194** bound parameter expansions.  ^The [SQLITE_OMIT_TRACE] compile-time
4195** option causes sqlite3_expanded_sql() to always return NULL.
4196**
4197** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
4198** are managed by SQLite and are automatically freed when the prepared
4199** statement is finalized.
4200** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
4201** is obtained from [sqlite3_malloc()] and must be freed by the application
4202** by passing it to [sqlite3_free()].
4203**
4204** ^The sqlite3_normalized_sql() interface is only available if
4205** the [SQLITE_ENABLE_NORMALIZE] compile-time option is defined.
4206*/
4207const char *sqlite3_sql(sqlite3_stmt *pStmt);
4208char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
4209#ifdef SQLITE_ENABLE_NORMALIZE
4210const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
4211#endif
4212
4213/*
4214** CAPI3REF: Determine If An SQL Statement Writes The Database
4215** METHOD: sqlite3_stmt
4216**
4217** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
4218** and only if the [prepared statement] X makes no direct changes to
4219** the content of the database file.
4220**
4221** Note that [application-defined SQL functions] or
4222** [virtual tables] might change the database indirectly as a side effect.
4223** ^(For example, if an application defines a function "eval()" that
4224** calls [sqlite3_exec()], then the following SQL statement would
4225** change the database file through side-effects:
4226**
4227** <blockquote><pre>
4228**    SELECT eval('DELETE FROM t1') FROM t2;
4229** </pre></blockquote>
4230**
4231** But because the [SELECT] statement does not change the database file
4232** directly, sqlite3_stmt_readonly() would still return true.)^
4233**
4234** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
4235** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
4236** since the statements themselves do not actually modify the database but
4237** rather they control the timing of when other statements modify the
4238** database.  ^The [ATTACH] and [DETACH] statements also cause
4239** sqlite3_stmt_readonly() to return true since, while those statements
4240** change the configuration of a database connection, they do not make
4241** changes to the content of the database files on disk.
4242** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
4243** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
4244** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
4245** sqlite3_stmt_readonly() returns false for those commands.
4246**
4247** ^This routine returns false if there is any possibility that the
4248** statement might change the database file.  ^A false return does
4249** not guarantee that the statement will change the database file.
4250** ^For example, an UPDATE statement might have a WHERE clause that
4251** makes it a no-op, but the sqlite3_stmt_readonly() result would still
4252** be false.  ^Similarly, a CREATE TABLE IF NOT EXISTS statement is a
4253** read-only no-op if the table already exists, but
4254** sqlite3_stmt_readonly() still returns false for such a statement.
4255*/
4256int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
4257
4258/*
4259** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement
4260** METHOD: sqlite3_stmt
4261**
4262** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the
4263** prepared statement S is an EXPLAIN statement, or 2 if the
4264** statement S is an EXPLAIN QUERY PLAN.
4265** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is
4266** an ordinary statement or a NULL pointer.
4267*/
4268int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);
4269
4270/*
4271** CAPI3REF: Determine If A Prepared Statement Has Been Reset
4272** METHOD: sqlite3_stmt
4273**
4274** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
4275** [prepared statement] S has been stepped at least once using
4276** [sqlite3_step(S)] but has neither run to completion (returned
4277** [SQLITE_DONE] from [sqlite3_step(S)]) nor
4278** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
4279** interface returns false if S is a NULL pointer.  If S is not a
4280** NULL pointer and is not a pointer to a valid [prepared statement]
4281** object, then the behavior is undefined and probably undesirable.
4282**
4283** This interface can be used in combination [sqlite3_next_stmt()]
4284** to locate all prepared statements associated with a database
4285** connection that are in need of being reset.  This can be used,
4286** for example, in diagnostic routines to search for prepared
4287** statements that are holding a transaction open.
4288*/
4289int sqlite3_stmt_busy(sqlite3_stmt*);
4290
4291/*
4292** CAPI3REF: Dynamically Typed Value Object
4293** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
4294**
4295** SQLite uses the sqlite3_value object to represent all values
4296** that can be stored in a database table. SQLite uses dynamic typing
4297** for the values it stores.  ^Values stored in sqlite3_value objects
4298** can be integers, floating point values, strings, BLOBs, or NULL.
4299**
4300** An sqlite3_value object may be either "protected" or "unprotected".
4301** Some interfaces require a protected sqlite3_value.  Other interfaces
4302** will accept either a protected or an unprotected sqlite3_value.
4303** Every interface that accepts sqlite3_value arguments specifies
4304** whether or not it requires a protected sqlite3_value.  The
4305** [sqlite3_value_dup()] interface can be used to construct a new
4306** protected sqlite3_value from an unprotected sqlite3_value.
4307**
4308** The terms "protected" and "unprotected" refer to whether or not
4309** a mutex is held.  An internal mutex is held for a protected
4310** sqlite3_value object but no mutex is held for an unprotected
4311** sqlite3_value object.  If SQLite is compiled to be single-threaded
4312** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
4313** or if SQLite is run in one of reduced mutex modes
4314** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
4315** then there is no distinction between protected and unprotected
4316** sqlite3_value objects and they can be used interchangeably.  However,
4317** for maximum code portability it is recommended that applications
4318** still make the distinction between protected and unprotected
4319** sqlite3_value objects even when not strictly required.
4320**
4321** ^The sqlite3_value objects that are passed as parameters into the
4322** implementation of [application-defined SQL functions] are protected.
4323** ^The sqlite3_value object returned by
4324** [sqlite3_column_value()] is unprotected.
4325** Unprotected sqlite3_value objects may only be used as arguments
4326** to [sqlite3_result_value()], [sqlite3_bind_value()], and
4327** [sqlite3_value_dup()].
4328** The [sqlite3_value_blob | sqlite3_value_type()] family of
4329** interfaces require protected sqlite3_value objects.
4330*/
4331typedef struct sqlite3_value sqlite3_value;
4332
4333/*
4334** CAPI3REF: SQL Function Context Object
4335**
4336** The context in which an SQL function executes is stored in an
4337** sqlite3_context object.  ^A pointer to an sqlite3_context object
4338** is always first parameter to [application-defined SQL functions].
4339** The application-defined SQL function implementation will pass this
4340** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
4341** [sqlite3_aggregate_context()], [sqlite3_user_data()],
4342** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
4343** and/or [sqlite3_set_auxdata()].
4344*/
4345typedef struct sqlite3_context sqlite3_context;
4346
4347/*
4348** CAPI3REF: Binding Values To Prepared Statements
4349** KEYWORDS: {host parameter} {host parameters} {host parameter name}
4350** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
4351** METHOD: sqlite3_stmt
4352**
4353** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
4354** literals may be replaced by a [parameter] that matches one of following
4355** templates:
4356**
4357** <ul>
4358** <li>  ?
4359** <li>  ?NNN
4360** <li>  :VVV
4361** <li>  @VVV
4362** <li>  $VVV
4363** </ul>
4364**
4365** In the templates above, NNN represents an integer literal,
4366** and VVV represents an alphanumeric identifier.)^  ^The values of these
4367** parameters (also called "host parameter names" or "SQL parameters")
4368** can be set using the sqlite3_bind_*() routines defined here.
4369**
4370** ^The first argument to the sqlite3_bind_*() routines is always
4371** a pointer to the [sqlite3_stmt] object returned from
4372** [sqlite3_prepare_v2()] or its variants.
4373**
4374** ^The second argument is the index of the SQL parameter to be set.
4375** ^The leftmost SQL parameter has an index of 1.  ^When the same named
4376** SQL parameter is used more than once, second and subsequent
4377** occurrences have the same index as the first occurrence.
4378** ^The index for named parameters can be looked up using the
4379** [sqlite3_bind_parameter_index()] API if desired.  ^The index
4380** for "?NNN" parameters is the value of NNN.
4381** ^The NNN value must be between 1 and the [sqlite3_limit()]
4382** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766).
4383**
4384** ^The third argument is the value to bind to the parameter.
4385** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4386** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
4387** is ignored and the end result is the same as sqlite3_bind_null().
4388** ^If the third parameter to sqlite3_bind_text() is not NULL, then
4389** it should be a pointer to well-formed UTF8 text.
4390** ^If the third parameter to sqlite3_bind_text16() is not NULL, then
4391** it should be a pointer to well-formed UTF16 text.
4392** ^If the third parameter to sqlite3_bind_text64() is not NULL, then
4393** it should be a pointer to a well-formed unicode string that is
4394** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16
4395** otherwise.
4396**
4397** [[byte-order determination rules]] ^The byte-order of
4398** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF)
4399** found in first character, which is removed, or in the absence of a BOM
4400** the byte order is the native byte order of the host
4401** machine for sqlite3_bind_text16() or the byte order specified in
4402** the 6th parameter for sqlite3_bind_text64().)^
4403** ^If UTF16 input text contains invalid unicode
4404** characters, then SQLite might change those invalid characters
4405** into the unicode replacement character: U+FFFD.
4406**
4407** ^(In those routines that have a fourth argument, its value is the
4408** number of bytes in the parameter.  To be clear: the value is the
4409** number of <u>bytes</u> in the value, not the number of characters.)^
4410** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4411** is negative, then the length of the string is
4412** the number of bytes up to the first zero terminator.
4413** If the fourth parameter to sqlite3_bind_blob() is negative, then
4414** the behavior is undefined.
4415** If a non-negative fourth parameter is provided to sqlite3_bind_text()
4416** or sqlite3_bind_text16() or sqlite3_bind_text64() then
4417** that parameter must be the byte offset
4418** where the NUL terminator would occur assuming the string were NUL
4419** terminated.  If any NUL characters occurs at byte offsets less than
4420** the value of the fourth parameter then the resulting string value will
4421** contain embedded NULs.  The result of expressions involving strings
4422** with embedded NULs is undefined.
4423**
4424** ^The fifth argument to the BLOB and string binding interfaces controls
4425** or indicates the lifetime of the object referenced by the third parameter.
4426** These three options exist:
4427** ^ (1) A destructor to dispose of the BLOB or string after SQLite has finished
4428** with it may be passed. ^It is called to dispose of the BLOB or string even
4429** if the call to the bind API fails, except the destructor is not called if
4430** the third parameter is a NULL pointer or the fourth parameter is negative.
4431** ^ (2) The special constant, [SQLITE_STATIC], may be passsed to indicate that
4432** the application remains responsible for disposing of the object. ^In this
4433** case, the object and the provided pointer to it must remain valid until
4434** either the prepared statement is finalized or the same SQL parameter is
4435** bound to something else, whichever occurs sooner.
4436** ^ (3) The constant, [SQLITE_TRANSIENT], may be passed to indicate that the
4437** object is to be copied prior to the return from sqlite3_bind_*(). ^The
4438** object and pointer to it must remain valid until then. ^SQLite will then
4439** manage the lifetime of its private copy.
4440**
4441** ^The sixth argument to sqlite3_bind_text64() must be one of
4442** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
4443** to specify the encoding of the text in the third parameter.  If
4444** the sixth argument to sqlite3_bind_text64() is not one of the
4445** allowed values shown above, or if the text encoding is different
4446** from the encoding specified by the sixth parameter, then the behavior
4447** is undefined.
4448**
4449** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
4450** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
4451** (just an integer to hold its size) while it is being processed.
4452** Zeroblobs are intended to serve as placeholders for BLOBs whose
4453** content is later written using
4454** [sqlite3_blob_open | incremental BLOB I/O] routines.
4455** ^A negative value for the zeroblob results in a zero-length BLOB.
4456**
4457** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
4458** [prepared statement] S to have an SQL value of NULL, but to also be
4459** associated with the pointer P of type T.  ^D is either a NULL pointer or
4460** a pointer to a destructor function for P. ^SQLite will invoke the
4461** destructor D with a single argument of P when it is finished using
4462** P.  The T parameter should be a static string, preferably a string
4463** literal. The sqlite3_bind_pointer() routine is part of the
4464** [pointer passing interface] added for SQLite 3.20.0.
4465**
4466** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
4467** for the [prepared statement] or with a prepared statement for which
4468** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
4469** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
4470** routine is passed a [prepared statement] that has been finalized, the
4471** result is undefined and probably harmful.
4472**
4473** ^Bindings are not cleared by the [sqlite3_reset()] routine.
4474** ^Unbound parameters are interpreted as NULL.
4475**
4476** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
4477** [error code] if anything goes wrong.
4478** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
4479** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
4480** [SQLITE_MAX_LENGTH].
4481** ^[SQLITE_RANGE] is returned if the parameter
4482** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
4483**
4484** See also: [sqlite3_bind_parameter_count()],
4485** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
4486*/
4487int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
4488int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
4489                        void(*)(void*));
4490int sqlite3_bind_double(sqlite3_stmt*, int, double);
4491int sqlite3_bind_int(sqlite3_stmt*, int, int);
4492int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
4493int sqlite3_bind_null(sqlite3_stmt*, int);
4494int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
4495int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
4496int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
4497                         void(*)(void*), unsigned char encoding);
4498int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
4499int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
4500int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
4501int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
4502
4503/*
4504** CAPI3REF: Number Of SQL Parameters
4505** METHOD: sqlite3_stmt
4506**
4507** ^This routine can be used to find the number of [SQL parameters]
4508** in a [prepared statement].  SQL parameters are tokens of the
4509** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
4510** placeholders for values that are [sqlite3_bind_blob | bound]
4511** to the parameters at a later time.
4512**
4513** ^(This routine actually returns the index of the largest (rightmost)
4514** parameter. For all forms except ?NNN, this will correspond to the
4515** number of unique parameters.  If parameters of the ?NNN form are used,
4516** there may be gaps in the list.)^
4517**
4518** See also: [sqlite3_bind_blob|sqlite3_bind()],
4519** [sqlite3_bind_parameter_name()], and
4520** [sqlite3_bind_parameter_index()].
4521*/
4522int sqlite3_bind_parameter_count(sqlite3_stmt*);
4523
4524/*
4525** CAPI3REF: Name Of A Host Parameter
4526** METHOD: sqlite3_stmt
4527**
4528** ^The sqlite3_bind_parameter_name(P,N) interface returns
4529** the name of the N-th [SQL parameter] in the [prepared statement] P.
4530** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
4531** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
4532** respectively.
4533** In other words, the initial ":" or "$" or "@" or "?"
4534** is included as part of the name.)^
4535** ^Parameters of the form "?" without a following integer have no name
4536** and are referred to as "nameless" or "anonymous parameters".
4537**
4538** ^The first host parameter has an index of 1, not 0.
4539**
4540** ^If the value N is out of range or if the N-th parameter is
4541** nameless, then NULL is returned.  ^The returned string is
4542** always in UTF-8 encoding even if the named parameter was
4543** originally specified as UTF-16 in [sqlite3_prepare16()],
4544** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4545**
4546** See also: [sqlite3_bind_blob|sqlite3_bind()],
4547** [sqlite3_bind_parameter_count()], and
4548** [sqlite3_bind_parameter_index()].
4549*/
4550const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
4551
4552/*
4553** CAPI3REF: Index Of A Parameter With A Given Name
4554** METHOD: sqlite3_stmt
4555**
4556** ^Return the index of an SQL parameter given its name.  ^The
4557** index value returned is suitable for use as the second
4558** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
4559** is returned if no matching parameter is found.  ^The parameter
4560** name must be given in UTF-8 even if the original statement
4561** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
4562** [sqlite3_prepare16_v3()].
4563**
4564** See also: [sqlite3_bind_blob|sqlite3_bind()],
4565** [sqlite3_bind_parameter_count()], and
4566** [sqlite3_bind_parameter_name()].
4567*/
4568int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
4569
4570/*
4571** CAPI3REF: Reset All Bindings On A Prepared Statement
4572** METHOD: sqlite3_stmt
4573**
4574** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
4575** the [sqlite3_bind_blob | bindings] on a [prepared statement].
4576** ^Use this routine to reset all host parameters to NULL.
4577*/
4578int sqlite3_clear_bindings(sqlite3_stmt*);
4579
4580/*
4581** CAPI3REF: Number Of Columns In A Result Set
4582** METHOD: sqlite3_stmt
4583**
4584** ^Return the number of columns in the result set returned by the
4585** [prepared statement]. ^If this routine returns 0, that means the
4586** [prepared statement] returns no data (for example an [UPDATE]).
4587** ^However, just because this routine returns a positive number does not
4588** mean that one or more rows of data will be returned.  ^A SELECT statement
4589** will always have a positive sqlite3_column_count() but depending on the
4590** WHERE clause constraints and the table content, it might return no rows.
4591**
4592** See also: [sqlite3_data_count()]
4593*/
4594int sqlite3_column_count(sqlite3_stmt *pStmt);
4595
4596/*
4597** CAPI3REF: Column Names In A Result Set
4598** METHOD: sqlite3_stmt
4599**
4600** ^These routines return the name assigned to a particular column
4601** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
4602** interface returns a pointer to a zero-terminated UTF-8 string
4603** and sqlite3_column_name16() returns a pointer to a zero-terminated
4604** UTF-16 string.  ^The first parameter is the [prepared statement]
4605** that implements the [SELECT] statement. ^The second parameter is the
4606** column number.  ^The leftmost column is number 0.
4607**
4608** ^The returned string pointer is valid until either the [prepared statement]
4609** is destroyed by [sqlite3_finalize()] or until the statement is automatically
4610** reprepared by the first call to [sqlite3_step()] for a particular run
4611** or until the next call to
4612** sqlite3_column_name() or sqlite3_column_name16() on the same column.
4613**
4614** ^If sqlite3_malloc() fails during the processing of either routine
4615** (for example during a conversion from UTF-8 to UTF-16) then a
4616** NULL pointer is returned.
4617**
4618** ^The name of a result column is the value of the "AS" clause for
4619** that column, if there is an AS clause.  If there is no AS clause
4620** then the name of the column is unspecified and may change from
4621** one release of SQLite to the next.
4622*/
4623const char *sqlite3_column_name(sqlite3_stmt*, int N);
4624const void *sqlite3_column_name16(sqlite3_stmt*, int N);
4625
4626/*
4627** CAPI3REF: Source Of Data In A Query Result
4628** METHOD: sqlite3_stmt
4629**
4630** ^These routines provide a means to determine the database, table, and
4631** table column that is the origin of a particular result column in
4632** [SELECT] statement.
4633** ^The name of the database or table or column can be returned as
4634** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
4635** the database name, the _table_ routines return the table name, and
4636** the origin_ routines return the column name.
4637** ^The returned string is valid until the [prepared statement] is destroyed
4638** using [sqlite3_finalize()] or until the statement is automatically
4639** reprepared by the first call to [sqlite3_step()] for a particular run
4640** or until the same information is requested
4641** again in a different encoding.
4642**
4643** ^The names returned are the original un-aliased names of the
4644** database, table, and column.
4645**
4646** ^The first argument to these interfaces is a [prepared statement].
4647** ^These functions return information about the Nth result column returned by
4648** the statement, where N is the second function argument.
4649** ^The left-most column is column 0 for these routines.
4650**
4651** ^If the Nth column returned by the statement is an expression or
4652** subquery and is not a column value, then all of these functions return
4653** NULL.  ^These routines might also return NULL if a memory allocation error
4654** occurs.  ^Otherwise, they return the name of the attached database, table,
4655** or column that query result column was extracted from.
4656**
4657** ^As with all other SQLite APIs, those whose names end with "16" return
4658** UTF-16 encoded strings and the other functions return UTF-8.
4659**
4660** ^These APIs are only available if the library was compiled with the
4661** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
4662**
4663** If two or more threads call one or more
4664** [sqlite3_column_database_name | column metadata interfaces]
4665** for the same [prepared statement] and result column
4666** at the same time then the results are undefined.
4667*/
4668const char *sqlite3_column_database_name(sqlite3_stmt*,int);
4669const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
4670const char *sqlite3_column_table_name(sqlite3_stmt*,int);
4671const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
4672const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
4673const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
4674
4675/*
4676** CAPI3REF: Declared Datatype Of A Query Result
4677** METHOD: sqlite3_stmt
4678**
4679** ^(The first parameter is a [prepared statement].
4680** If this statement is a [SELECT] statement and the Nth column of the
4681** returned result set of that [SELECT] is a table column (not an
4682** expression or subquery) then the declared type of the table
4683** column is returned.)^  ^If the Nth column of the result set is an
4684** expression or subquery, then a NULL pointer is returned.
4685** ^The returned string is always UTF-8 encoded.
4686**
4687** ^(For example, given the database schema:
4688**
4689** CREATE TABLE t1(c1 VARIANT);
4690**
4691** and the following statement to be compiled:
4692**
4693** SELECT c1 + 1, c1 FROM t1;
4694**
4695** this routine would return the string "VARIANT" for the second result
4696** column (i==1), and a NULL pointer for the first result column (i==0).)^
4697**
4698** ^SQLite uses dynamic run-time typing.  ^So just because a column
4699** is declared to contain a particular type does not mean that the
4700** data stored in that column is of the declared type.  SQLite is
4701** strongly typed, but the typing is dynamic not static.  ^Type
4702** is associated with individual values, not with the containers
4703** used to hold those values.
4704*/
4705const char *sqlite3_column_decltype(sqlite3_stmt*,int);
4706const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
4707
4708/*
4709** CAPI3REF: Evaluate An SQL Statement
4710** METHOD: sqlite3_stmt
4711**
4712** After a [prepared statement] has been prepared using any of
4713** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
4714** or [sqlite3_prepare16_v3()] or one of the legacy
4715** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
4716** must be called one or more times to evaluate the statement.
4717**
4718** The details of the behavior of the sqlite3_step() interface depend
4719** on whether the statement was prepared using the newer "vX" interfaces
4720** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
4721** [sqlite3_prepare16_v2()] or the older legacy
4722** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
4723** new "vX" interface is recommended for new applications but the legacy
4724** interface will continue to be supported.
4725**
4726** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
4727** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
4728** ^With the "v2" interface, any of the other [result codes] or
4729** [extended result codes] might be returned as well.
4730**
4731** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
4732** database locks it needs to do its job.  ^If the statement is a [COMMIT]
4733** or occurs outside of an explicit transaction, then you can retry the
4734** statement.  If the statement is not a [COMMIT] and occurs within an
4735** explicit transaction then you should rollback the transaction before
4736** continuing.
4737**
4738** ^[SQLITE_DONE] means that the statement has finished executing
4739** successfully.  sqlite3_step() should not be called again on this virtual
4740** machine without first calling [sqlite3_reset()] to reset the virtual
4741** machine back to its initial state.
4742**
4743** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
4744** is returned each time a new row of data is ready for processing by the
4745** caller. The values may be accessed using the [column access functions].
4746** sqlite3_step() is called again to retrieve the next row of data.
4747**
4748** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
4749** violation) has occurred.  sqlite3_step() should not be called again on
4750** the VM. More information may be found by calling [sqlite3_errmsg()].
4751** ^With the legacy interface, a more specific error code (for example,
4752** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
4753** can be obtained by calling [sqlite3_reset()] on the
4754** [prepared statement].  ^In the "v2" interface,
4755** the more specific error code is returned directly by sqlite3_step().
4756**
4757** [SQLITE_MISUSE] means that the this routine was called inappropriately.
4758** Perhaps it was called on a [prepared statement] that has
4759** already been [sqlite3_finalize | finalized] or on one that had
4760** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
4761** be the case that the same database connection is being used by two or
4762** more threads at the same moment in time.
4763**
4764** For all versions of SQLite up to and including 3.6.23.1, a call to
4765** [sqlite3_reset()] was required after sqlite3_step() returned anything
4766** other than [SQLITE_ROW] before any subsequent invocation of
4767** sqlite3_step().  Failure to reset the prepared statement using
4768** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
4769** sqlite3_step().  But after [version 3.6.23.1] ([dateof:3.6.23.1],
4770** sqlite3_step() began
4771** calling [sqlite3_reset()] automatically in this circumstance rather
4772** than returning [SQLITE_MISUSE].  This is not considered a compatibility
4773** break because any application that ever receives an SQLITE_MISUSE error
4774** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
4775** can be used to restore the legacy behavior.
4776**
4777** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
4778** API always returns a generic error code, [SQLITE_ERROR], following any
4779** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
4780** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
4781** specific [error codes] that better describes the error.
4782** We admit that this is a goofy design.  The problem has been fixed
4783** with the "v2" interface.  If you prepare all of your SQL statements
4784** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
4785** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
4786** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
4787** then the more specific [error codes] are returned directly
4788** by sqlite3_step().  The use of the "vX" interfaces is recommended.
4789*/
4790int sqlite3_step(sqlite3_stmt*);
4791
4792/*
4793** CAPI3REF: Number of columns in a result set
4794** METHOD: sqlite3_stmt
4795**
4796** ^The sqlite3_data_count(P) interface returns the number of columns in the
4797** current row of the result set of [prepared statement] P.
4798** ^If prepared statement P does not have results ready to return
4799** (via calls to the [sqlite3_column_int | sqlite3_column()] family of
4800** interfaces) then sqlite3_data_count(P) returns 0.
4801** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
4802** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
4803** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
4804** will return non-zero if previous call to [sqlite3_step](P) returned
4805** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
4806** where it always returns zero since each step of that multi-step
4807** pragma returns 0 columns of data.
4808**
4809** See also: [sqlite3_column_count()]
4810*/
4811int sqlite3_data_count(sqlite3_stmt *pStmt);
4812
4813/*
4814** CAPI3REF: Fundamental Datatypes
4815** KEYWORDS: SQLITE_TEXT
4816**
4817** ^(Every value in SQLite has one of five fundamental datatypes:
4818**
4819** <ul>
4820** <li> 64-bit signed integer
4821** <li> 64-bit IEEE floating point number
4822** <li> string
4823** <li> BLOB
4824** <li> NULL
4825** </ul>)^
4826**
4827** These constants are codes for each of those types.
4828**
4829** Note that the SQLITE_TEXT constant was also used in SQLite version 2
4830** for a completely different meaning.  Software that links against both
4831** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
4832** SQLITE_TEXT.
4833*/
4834#define SQLITE_INTEGER  1
4835#define SQLITE_FLOAT    2
4836#define SQLITE_BLOB     4
4837#define SQLITE_NULL     5
4838#ifdef SQLITE_TEXT
4839# undef SQLITE_TEXT
4840#else
4841# define SQLITE_TEXT     3
4842#endif
4843#define SQLITE3_TEXT     3
4844
4845/*
4846** CAPI3REF: Result Values From A Query
4847** KEYWORDS: {column access functions}
4848** METHOD: sqlite3_stmt
4849**
4850** <b>Summary:</b>
4851** <blockquote><table border=0 cellpadding=0 cellspacing=0>
4852** <tr><td><b>sqlite3_column_blob</b><td>&rarr;<td>BLOB result
4853** <tr><td><b>sqlite3_column_double</b><td>&rarr;<td>REAL result
4854** <tr><td><b>sqlite3_column_int</b><td>&rarr;<td>32-bit INTEGER result
4855** <tr><td><b>sqlite3_column_int64</b><td>&rarr;<td>64-bit INTEGER result
4856** <tr><td><b>sqlite3_column_text</b><td>&rarr;<td>UTF-8 TEXT result
4857** <tr><td><b>sqlite3_column_text16</b><td>&rarr;<td>UTF-16 TEXT result
4858** <tr><td><b>sqlite3_column_value</b><td>&rarr;<td>The result as an
4859** [sqlite3_value|unprotected sqlite3_value] object.
4860** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
4861** <tr><td><b>sqlite3_column_bytes</b><td>&rarr;<td>Size of a BLOB
4862** or a UTF-8 TEXT result in bytes
4863** <tr><td><b>sqlite3_column_bytes16&nbsp;&nbsp;</b>
4864** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
4865** TEXT in bytes
4866** <tr><td><b>sqlite3_column_type</b><td>&rarr;<td>Default
4867** datatype of the result
4868** </table></blockquote>
4869**
4870** <b>Details:</b>
4871**
4872** ^These routines return information about a single column of the current
4873** result row of a query.  ^In every case the first argument is a pointer
4874** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
4875** that was returned from [sqlite3_prepare_v2()] or one of its variants)
4876** and the second argument is the index of the column for which information
4877** should be returned. ^The leftmost column of the result set has the index 0.
4878** ^The number of columns in the result can be determined using
4879** [sqlite3_column_count()].
4880**
4881** If the SQL statement does not currently point to a valid row, or if the
4882** column index is out of range, the result is undefined.
4883** These routines may only be called when the most recent call to
4884** [sqlite3_step()] has returned [SQLITE_ROW] and neither
4885** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
4886** If any of these routines are called after [sqlite3_reset()] or
4887** [sqlite3_finalize()] or after [sqlite3_step()] has returned
4888** something other than [SQLITE_ROW], the results are undefined.
4889** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
4890** are called from a different thread while any of these routines
4891** are pending, then the results are undefined.
4892**
4893** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
4894** each return the value of a result column in a specific data format.  If
4895** the result column is not initially in the requested format (for example,
4896** if the query returns an integer but the sqlite3_column_text() interface
4897** is used to extract the value) then an automatic type conversion is performed.
4898**
4899** ^The sqlite3_column_type() routine returns the
4900** [SQLITE_INTEGER | datatype code] for the initial data type
4901** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
4902** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
4903** The return value of sqlite3_column_type() can be used to decide which
4904** of the first six interface should be used to extract the column value.
4905** The value returned by sqlite3_column_type() is only meaningful if no
4906** automatic type conversions have occurred for the value in question.
4907** After a type conversion, the result of calling sqlite3_column_type()
4908** is undefined, though harmless.  Future
4909** versions of SQLite may change the behavior of sqlite3_column_type()
4910** following a type conversion.
4911**
4912** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
4913** or sqlite3_column_bytes16() interfaces can be used to determine the size
4914** of that BLOB or string.
4915**
4916** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
4917** routine returns the number of bytes in that BLOB or string.
4918** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
4919** the string to UTF-8 and then returns the number of bytes.
4920** ^If the result is a numeric value then sqlite3_column_bytes() uses
4921** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
4922** the number of bytes in that string.
4923** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
4924**
4925** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
4926** routine returns the number of bytes in that BLOB or string.
4927** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
4928** the string to UTF-16 and then returns the number of bytes.
4929** ^If the result is a numeric value then sqlite3_column_bytes16() uses
4930** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
4931** the number of bytes in that string.
4932** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
4933**
4934** ^The values returned by [sqlite3_column_bytes()] and
4935** [sqlite3_column_bytes16()] do not include the zero terminators at the end
4936** of the string.  ^For clarity: the values returned by
4937** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
4938** bytes in the string, not the number of characters.
4939**
4940** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
4941** even empty strings, are always zero-terminated.  ^The return
4942** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
4943**
4944** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
4945** [unprotected sqlite3_value] object.  In a multithreaded environment,
4946** an unprotected sqlite3_value object may only be used safely with
4947** [sqlite3_bind_value()] and [sqlite3_result_value()].
4948** If the [unprotected sqlite3_value] object returned by
4949** [sqlite3_column_value()] is used in any other way, including calls
4950** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
4951** or [sqlite3_value_bytes()], the behavior is not threadsafe.
4952** Hence, the sqlite3_column_value() interface
4953** is normally only useful within the implementation of
4954** [application-defined SQL functions] or [virtual tables], not within
4955** top-level application code.
4956**
4957** The these routines may attempt to convert the datatype of the result.
4958** ^For example, if the internal representation is FLOAT and a text result
4959** is requested, [sqlite3_snprintf()] is used internally to perform the
4960** conversion automatically.  ^(The following table details the conversions
4961** that are applied:
4962**
4963** <blockquote>
4964** <table border="1">
4965** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
4966**
4967** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
4968** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
4969** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
4970** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
4971** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
4972** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
4973** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
4974** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
4975** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
4976** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
4977** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
4978** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
4979** <tr><td>  TEXT    <td>   BLOB    <td> No change
4980** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
4981** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
4982** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
4983** </table>
4984** </blockquote>)^
4985**
4986** Note that when type conversions occur, pointers returned by prior
4987** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
4988** sqlite3_column_text16() may be invalidated.
4989** Type conversions and pointer invalidations might occur
4990** in the following cases:
4991**
4992** <ul>
4993** <li> The initial content is a BLOB and sqlite3_column_text() or
4994**      sqlite3_column_text16() is called.  A zero-terminator might
4995**      need to be added to the string.</li>
4996** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
4997**      sqlite3_column_text16() is called.  The content must be converted
4998**      to UTF-16.</li>
4999** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
5000**      sqlite3_column_text() is called.  The content must be converted
5001**      to UTF-8.</li>
5002** </ul>
5003**
5004** ^Conversions between UTF-16be and UTF-16le are always done in place and do
5005** not invalidate a prior pointer, though of course the content of the buffer
5006** that the prior pointer references will have been modified.  Other kinds
5007** of conversion are done in place when it is possible, but sometimes they
5008** are not possible and in those cases prior pointers are invalidated.
5009**
5010** The safest policy is to invoke these routines
5011** in one of the following ways:
5012**
5013** <ul>
5014**  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
5015**  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
5016**  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
5017** </ul>
5018**
5019** In other words, you should call sqlite3_column_text(),
5020** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
5021** into the desired format, then invoke sqlite3_column_bytes() or
5022** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
5023** to sqlite3_column_text() or sqlite3_column_blob() with calls to
5024** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
5025** with calls to sqlite3_column_bytes().
5026**
5027** ^The pointers returned are valid until a type conversion occurs as
5028** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
5029** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
5030** and BLOBs is freed automatically.  Do not pass the pointers returned
5031** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
5032** [sqlite3_free()].
5033**
5034** As long as the input parameters are correct, these routines will only
5035** fail if an out-of-memory error occurs during a format conversion.
5036** Only the following subset of interfaces are subject to out-of-memory
5037** errors:
5038**
5039** <ul>
5040** <li> sqlite3_column_blob()
5041** <li> sqlite3_column_text()
5042** <li> sqlite3_column_text16()
5043** <li> sqlite3_column_bytes()
5044** <li> sqlite3_column_bytes16()
5045** </ul>
5046**
5047** If an out-of-memory error occurs, then the return value from these
5048** routines is the same as if the column had contained an SQL NULL value.
5049** Valid SQL NULL returns can be distinguished from out-of-memory errors
5050** by invoking the [sqlite3_errcode()] immediately after the suspect
5051** return value is obtained and before any
5052** other SQLite interface is called on the same [database connection].
5053*/
5054const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
5055double sqlite3_column_double(sqlite3_stmt*, int iCol);
5056int sqlite3_column_int(sqlite3_stmt*, int iCol);
5057sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
5058const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
5059const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
5060sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
5061int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
5062int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
5063int sqlite3_column_type(sqlite3_stmt*, int iCol);
5064
5065/*
5066** CAPI3REF: Destroy A Prepared Statement Object
5067** DESTRUCTOR: sqlite3_stmt
5068**
5069** ^The sqlite3_finalize() function is called to delete a [prepared statement].
5070** ^If the most recent evaluation of the statement encountered no errors
5071** or if the statement is never been evaluated, then sqlite3_finalize() returns
5072** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
5073** sqlite3_finalize(S) returns the appropriate [error code] or
5074** [extended error code].
5075**
5076** ^The sqlite3_finalize(S) routine can be called at any point during
5077** the life cycle of [prepared statement] S:
5078** before statement S is ever evaluated, after
5079** one or more calls to [sqlite3_reset()], or after any call
5080** to [sqlite3_step()] regardless of whether or not the statement has
5081** completed execution.
5082**
5083** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
5084**
5085** The application must finalize every [prepared statement] in order to avoid
5086** resource leaks.  It is a grievous error for the application to try to use
5087** a prepared statement after it has been finalized.  Any use of a prepared
5088** statement after it has been finalized can result in undefined and
5089** undesirable behavior such as segfaults and heap corruption.
5090*/
5091int sqlite3_finalize(sqlite3_stmt *pStmt);
5092
5093/*
5094** CAPI3REF: Reset A Prepared Statement Object
5095** METHOD: sqlite3_stmt
5096**
5097** The sqlite3_reset() function is called to reset a [prepared statement]
5098** object back to its initial state, ready to be re-executed.
5099** ^Any SQL statement variables that had values bound to them using
5100** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
5101** Use [sqlite3_clear_bindings()] to reset the bindings.
5102**
5103** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
5104** back to the beginning of its program.
5105**
5106** ^If the most recent call to [sqlite3_step(S)] for the
5107** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
5108** or if [sqlite3_step(S)] has never before been called on S,
5109** then [sqlite3_reset(S)] returns [SQLITE_OK].
5110**
5111** ^If the most recent call to [sqlite3_step(S)] for the
5112** [prepared statement] S indicated an error, then
5113** [sqlite3_reset(S)] returns an appropriate [error code].
5114**
5115** ^The [sqlite3_reset(S)] interface does not change the values
5116** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
5117*/
5118int sqlite3_reset(sqlite3_stmt *pStmt);
5119
5120/*
5121** CAPI3REF: Create Or Redefine SQL Functions
5122** KEYWORDS: {function creation routines}
5123** METHOD: sqlite3
5124**
5125** ^These functions (collectively known as "function creation routines")
5126** are used to add SQL functions or aggregates or to redefine the behavior
5127** of existing SQL functions or aggregates. The only differences between
5128** the three "sqlite3_create_function*" routines are the text encoding
5129** expected for the second parameter (the name of the function being
5130** created) and the presence or absence of a destructor callback for
5131** the application data pointer. Function sqlite3_create_window_function()
5132** is similar, but allows the user to supply the extra callback functions
5133** needed by [aggregate window functions].
5134**
5135** ^The first parameter is the [database connection] to which the SQL
5136** function is to be added.  ^If an application uses more than one database
5137** connection then application-defined SQL functions must be added
5138** to each database connection separately.
5139**
5140** ^The second parameter is the name of the SQL function to be created or
5141** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
5142** representation, exclusive of the zero-terminator.  ^Note that the name
5143** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
5144** ^Any attempt to create a function with a longer name
5145** will result in [SQLITE_MISUSE] being returned.
5146**
5147** ^The third parameter (nArg)
5148** is the number of arguments that the SQL function or
5149** aggregate takes. ^If this parameter is -1, then the SQL function or
5150** aggregate may take any number of arguments between 0 and the limit
5151** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
5152** parameter is less than -1 or greater than 127 then the behavior is
5153** undefined.
5154**
5155** ^The fourth parameter, eTextRep, specifies what
5156** [SQLITE_UTF8 | text encoding] this SQL function prefers for
5157** its parameters.  The application should set this parameter to
5158** [SQLITE_UTF16LE] if the function implementation invokes
5159** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
5160** implementation invokes [sqlite3_value_text16be()] on an input, or
5161** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
5162** otherwise.  ^The same SQL function may be registered multiple times using
5163** different preferred text encodings, with different implementations for
5164** each encoding.
5165** ^When multiple implementations of the same function are available, SQLite
5166** will pick the one that involves the least amount of data conversion.
5167**
5168** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
5169** to signal that the function will always return the same result given
5170** the same inputs within a single SQL statement.  Most SQL functions are
5171** deterministic.  The built-in [random()] SQL function is an example of a
5172** function that is not deterministic.  The SQLite query planner is able to
5173** perform additional optimizations on deterministic functions, so use
5174** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
5175**
5176** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY]
5177** flag, which if present prevents the function from being invoked from
5178** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions,
5179** index expressions, or the WHERE clause of partial indexes.
5180**
5181** For best security, the [SQLITE_DIRECTONLY] flag is recommended for
5182** all application-defined SQL functions that do not need to be
5183** used inside of triggers, view, CHECK constraints, or other elements of
5184** the database schema.  This flags is especially recommended for SQL
5185** functions that have side effects or reveal internal application state.
5186** Without this flag, an attacker might be able to modify the schema of
5187** a database file to include invocations of the function with parameters
5188** chosen by the attacker, which the application will then execute when
5189** the database file is opened and read.
5190**
5191** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
5192** function can gain access to this pointer using [sqlite3_user_data()].)^
5193**
5194** ^The sixth, seventh and eighth parameters passed to the three
5195** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
5196** pointers to C-language functions that implement the SQL function or
5197** aggregate. ^A scalar SQL function requires an implementation of the xFunc
5198** callback only; NULL pointers must be passed as the xStep and xFinal
5199** parameters. ^An aggregate SQL function requires an implementation of xStep
5200** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
5201** SQL function or aggregate, pass NULL pointers for all three function
5202** callbacks.
5203**
5204** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
5205** and xInverse) passed to sqlite3_create_window_function are pointers to
5206** C-language callbacks that implement the new function. xStep and xFinal
5207** must both be non-NULL. xValue and xInverse may either both be NULL, in
5208** which case a regular aggregate function is created, or must both be
5209** non-NULL, in which case the new function may be used as either an aggregate
5210** or aggregate window function. More details regarding the implementation
5211** of aggregate window functions are
5212** [user-defined window functions|available here].
5213**
5214** ^(If the final parameter to sqlite3_create_function_v2() or
5215** sqlite3_create_window_function() is not NULL, then it is destructor for
5216** the application data pointer. The destructor is invoked when the function
5217** is deleted, either by being overloaded or when the database connection
5218** closes.)^ ^The destructor is also invoked if the call to
5219** sqlite3_create_function_v2() fails.  ^When the destructor callback is
5220** invoked, it is passed a single argument which is a copy of the application
5221** data pointer which was the fifth parameter to sqlite3_create_function_v2().
5222**
5223** ^It is permitted to register multiple implementations of the same
5224** functions with the same name but with either differing numbers of
5225** arguments or differing preferred text encodings.  ^SQLite will use
5226** the implementation that most closely matches the way in which the
5227** SQL function is used.  ^A function implementation with a non-negative
5228** nArg parameter is a better match than a function implementation with
5229** a negative nArg.  ^A function where the preferred text encoding
5230** matches the database encoding is a better
5231** match than a function where the encoding is different.
5232** ^A function where the encoding difference is between UTF16le and UTF16be
5233** is a closer match than a function where the encoding difference is
5234** between UTF8 and UTF16.
5235**
5236** ^Built-in functions may be overloaded by new application-defined functions.
5237**
5238** ^An application-defined function is permitted to call other
5239** SQLite interfaces.  However, such calls must not
5240** close the database connection nor finalize or reset the prepared
5241** statement in which the function is running.
5242*/
5243int sqlite3_create_function(
5244  sqlite3 *db,
5245  const char *zFunctionName,
5246  int nArg,
5247  int eTextRep,
5248  void *pApp,
5249  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
5250  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5251  void (*xFinal)(sqlite3_context*)
5252);
5253int sqlite3_create_function16(
5254  sqlite3 *db,
5255  const void *zFunctionName,
5256  int nArg,
5257  int eTextRep,
5258  void *pApp,
5259  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
5260  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5261  void (*xFinal)(sqlite3_context*)
5262);
5263int sqlite3_create_function_v2(
5264  sqlite3 *db,
5265  const char *zFunctionName,
5266  int nArg,
5267  int eTextRep,
5268  void *pApp,
5269  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
5270  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5271  void (*xFinal)(sqlite3_context*),
5272  void(*xDestroy)(void*)
5273);
5274int sqlite3_create_window_function(
5275  sqlite3 *db,
5276  const char *zFunctionName,
5277  int nArg,
5278  int eTextRep,
5279  void *pApp,
5280  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5281  void (*xFinal)(sqlite3_context*),
5282  void (*xValue)(sqlite3_context*),
5283  void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
5284  void(*xDestroy)(void*)
5285);
5286
5287/*
5288** CAPI3REF: Text Encodings
5289**
5290** These constant define integer codes that represent the various
5291** text encodings supported by SQLite.
5292*/
5293#define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
5294#define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
5295#define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
5296#define SQLITE_UTF16          4    /* Use native byte order */
5297#define SQLITE_ANY            5    /* Deprecated */
5298#define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
5299
5300/*
5301** CAPI3REF: Function Flags
5302**
5303** These constants may be ORed together with the
5304** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
5305** to [sqlite3_create_function()], [sqlite3_create_function16()], or
5306** [sqlite3_create_function_v2()].
5307**
5308** <dl>
5309** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd>
5310** The SQLITE_DETERMINISTIC flag means that the new function always gives
5311** the same output when the input parameters are the same.
5312** The [abs|abs() function] is deterministic, for example, but
5313** [randomblob|randomblob()] is not.  Functions must
5314** be deterministic in order to be used in certain contexts such as
5315** with the WHERE clause of [partial indexes] or in [generated columns].
5316** SQLite might also optimize deterministic functions by factoring them
5317** out of inner loops.
5318** </dd>
5319**
5320** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd>
5321** The SQLITE_DIRECTONLY flag means that the function may only be invoked
5322** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in
5323** schema structures such as [CHECK constraints], [DEFAULT clauses],
5324** [expression indexes], [partial indexes], or [generated columns].
5325** The SQLITE_DIRECTONLY flags is a security feature which is recommended
5326** for all [application-defined SQL functions], and especially for functions
5327** that have side-effects or that could potentially leak sensitive
5328** information.
5329** </dd>
5330**
5331** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd>
5332** The SQLITE_INNOCUOUS flag means that the function is unlikely
5333** to cause problems even if misused.  An innocuous function should have
5334** no side effects and should not depend on any values other than its
5335** input parameters. The [abs|abs() function] is an example of an
5336** innocuous function.
5337** The [load_extension() SQL function] is not innocuous because of its
5338** side effects.
5339** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not
5340** exactly the same.  The [random|random() function] is an example of a
5341** function that is innocuous but not deterministic.
5342** <p>Some heightened security settings
5343** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF])
5344** disable the use of SQL functions inside views and triggers and in
5345** schema structures such as [CHECK constraints], [DEFAULT clauses],
5346** [expression indexes], [partial indexes], and [generated columns] unless
5347** the function is tagged with SQLITE_INNOCUOUS.  Most built-in functions
5348** are innocuous.  Developers are advised to avoid using the
5349** SQLITE_INNOCUOUS flag for application-defined functions unless the
5350** function has been carefully audited and found to be free of potentially
5351** security-adverse side-effects and information-leaks.
5352** </dd>
5353**
5354** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd>
5355** The SQLITE_SUBTYPE flag indicates to SQLite that a function may call
5356** [sqlite3_value_subtype()] to inspect the sub-types of its arguments.
5357** Specifying this flag makes no difference for scalar or aggregate user
5358** functions. However, if it is not specified for a user-defined window
5359** function, then any sub-types belonging to arguments passed to the window
5360** function may be discarded before the window function is called (i.e.
5361** sqlite3_value_subtype() will always return 0).
5362** </dd>
5363** </dl>
5364*/
5365#define SQLITE_DETERMINISTIC    0x000000800
5366#define SQLITE_DIRECTONLY       0x000080000
5367#define SQLITE_SUBTYPE          0x000100000
5368#define SQLITE_INNOCUOUS        0x000200000
5369
5370/*
5371** CAPI3REF: Deprecated Functions
5372** DEPRECATED
5373**
5374** These functions are [deprecated].  In order to maintain
5375** backwards compatibility with older code, these functions continue
5376** to be supported.  However, new applications should avoid
5377** the use of these functions.  To encourage programmers to avoid
5378** these functions, we will not explain what they do.
5379*/
5380#ifndef SQLITE_OMIT_DEPRECATED
5381SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
5382SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
5383SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
5384SQLITE_DEPRECATED int sqlite3_global_recover(void);
5385SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
5386SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
5387                      void*,sqlite3_int64);
5388#endif
5389
5390/*
5391** CAPI3REF: Obtaining SQL Values
5392** METHOD: sqlite3_value
5393**
5394** <b>Summary:</b>
5395** <blockquote><table border=0 cellpadding=0 cellspacing=0>
5396** <tr><td><b>sqlite3_value_blob</b><td>&rarr;<td>BLOB value
5397** <tr><td><b>sqlite3_value_double</b><td>&rarr;<td>REAL value
5398** <tr><td><b>sqlite3_value_int</b><td>&rarr;<td>32-bit INTEGER value
5399** <tr><td><b>sqlite3_value_int64</b><td>&rarr;<td>64-bit INTEGER value
5400** <tr><td><b>sqlite3_value_pointer</b><td>&rarr;<td>Pointer value
5401** <tr><td><b>sqlite3_value_text</b><td>&rarr;<td>UTF-8 TEXT value
5402** <tr><td><b>sqlite3_value_text16</b><td>&rarr;<td>UTF-16 TEXT value in
5403** the native byteorder
5404** <tr><td><b>sqlite3_value_text16be</b><td>&rarr;<td>UTF-16be TEXT value
5405** <tr><td><b>sqlite3_value_text16le</b><td>&rarr;<td>UTF-16le TEXT value
5406** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
5407** <tr><td><b>sqlite3_value_bytes</b><td>&rarr;<td>Size of a BLOB
5408** or a UTF-8 TEXT in bytes
5409** <tr><td><b>sqlite3_value_bytes16&nbsp;&nbsp;</b>
5410** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
5411** TEXT in bytes
5412** <tr><td><b>sqlite3_value_type</b><td>&rarr;<td>Default
5413** datatype of the value
5414** <tr><td><b>sqlite3_value_numeric_type&nbsp;&nbsp;</b>
5415** <td>&rarr;&nbsp;&nbsp;<td>Best numeric datatype of the value
5416** <tr><td><b>sqlite3_value_nochange&nbsp;&nbsp;</b>
5417** <td>&rarr;&nbsp;&nbsp;<td>True if the column is unchanged in an UPDATE
5418** against a virtual table.
5419** <tr><td><b>sqlite3_value_frombind&nbsp;&nbsp;</b>
5420** <td>&rarr;&nbsp;&nbsp;<td>True if value originated from a [bound parameter]
5421** </table></blockquote>
5422**
5423** <b>Details:</b>
5424**
5425** These routines extract type, size, and content information from
5426** [protected sqlite3_value] objects.  Protected sqlite3_value objects
5427** are used to pass parameter information into the functions that
5428** implement [application-defined SQL functions] and [virtual tables].
5429**
5430** These routines work only with [protected sqlite3_value] objects.
5431** Any attempt to use these routines on an [unprotected sqlite3_value]
5432** is not threadsafe.
5433**
5434** ^These routines work just like the corresponding [column access functions]
5435** except that these routines take a single [protected sqlite3_value] object
5436** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
5437**
5438** ^The sqlite3_value_text16() interface extracts a UTF-16 string
5439** in the native byte-order of the host machine.  ^The
5440** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
5441** extract UTF-16 strings as big-endian and little-endian respectively.
5442**
5443** ^If [sqlite3_value] object V was initialized
5444** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
5445** and if X and Y are strings that compare equal according to strcmp(X,Y),
5446** then sqlite3_value_pointer(V,Y) will return the pointer P.  ^Otherwise,
5447** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
5448** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5449**
5450** ^(The sqlite3_value_type(V) interface returns the
5451** [SQLITE_INTEGER | datatype code] for the initial datatype of the
5452** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
5453** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
5454** Other interfaces might change the datatype for an sqlite3_value object.
5455** For example, if the datatype is initially SQLITE_INTEGER and
5456** sqlite3_value_text(V) is called to extract a text value for that
5457** integer, then subsequent calls to sqlite3_value_type(V) might return
5458** SQLITE_TEXT.  Whether or not a persistent internal datatype conversion
5459** occurs is undefined and may change from one release of SQLite to the next.
5460**
5461** ^(The sqlite3_value_numeric_type() interface attempts to apply
5462** numeric affinity to the value.  This means that an attempt is
5463** made to convert the value to an integer or floating point.  If
5464** such a conversion is possible without loss of information (in other
5465** words, if the value is a string that looks like a number)
5466** then the conversion is performed.  Otherwise no conversion occurs.
5467** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
5468**
5469** ^Within the [xUpdate] method of a [virtual table], the
5470** sqlite3_value_nochange(X) interface returns true if and only if
5471** the column corresponding to X is unchanged by the UPDATE operation
5472** that the xUpdate method call was invoked to implement and if
5473** and the prior [xColumn] method call that was invoked to extracted
5474** the value for that column returned without setting a result (probably
5475** because it queried [sqlite3_vtab_nochange()] and found that the column
5476** was unchanging).  ^Within an [xUpdate] method, any value for which
5477** sqlite3_value_nochange(X) is true will in all other respects appear
5478** to be a NULL value.  If sqlite3_value_nochange(X) is invoked anywhere other
5479** than within an [xUpdate] method call for an UPDATE statement, then
5480** the return value is arbitrary and meaningless.
5481**
5482** ^The sqlite3_value_frombind(X) interface returns non-zero if the
5483** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()]
5484** interfaces.  ^If X comes from an SQL literal value, or a table column,
5485** or an expression, then sqlite3_value_frombind(X) returns zero.
5486**
5487** Please pay particular attention to the fact that the pointer returned
5488** from [sqlite3_value_blob()], [sqlite3_value_text()], or
5489** [sqlite3_value_text16()] can be invalidated by a subsequent call to
5490** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
5491** or [sqlite3_value_text16()].
5492**
5493** These routines must be called from the same thread as
5494** the SQL function that supplied the [sqlite3_value*] parameters.
5495**
5496** As long as the input parameter is correct, these routines can only
5497** fail if an out-of-memory error occurs during a format conversion.
5498** Only the following subset of interfaces are subject to out-of-memory
5499** errors:
5500**
5501** <ul>
5502** <li> sqlite3_value_blob()
5503** <li> sqlite3_value_text()
5504** <li> sqlite3_value_text16()
5505** <li> sqlite3_value_text16le()
5506** <li> sqlite3_value_text16be()
5507** <li> sqlite3_value_bytes()
5508** <li> sqlite3_value_bytes16()
5509** </ul>
5510**
5511** If an out-of-memory error occurs, then the return value from these
5512** routines is the same as if the column had contained an SQL NULL value.
5513** Valid SQL NULL returns can be distinguished from out-of-memory errors
5514** by invoking the [sqlite3_errcode()] immediately after the suspect
5515** return value is obtained and before any
5516** other SQLite interface is called on the same [database connection].
5517*/
5518const void *sqlite3_value_blob(sqlite3_value*);
5519double sqlite3_value_double(sqlite3_value*);
5520int sqlite3_value_int(sqlite3_value*);
5521sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
5522void *sqlite3_value_pointer(sqlite3_value*, const char*);
5523const unsigned char *sqlite3_value_text(sqlite3_value*);
5524const void *sqlite3_value_text16(sqlite3_value*);
5525const void *sqlite3_value_text16le(sqlite3_value*);
5526const void *sqlite3_value_text16be(sqlite3_value*);
5527int sqlite3_value_bytes(sqlite3_value*);
5528int sqlite3_value_bytes16(sqlite3_value*);
5529int sqlite3_value_type(sqlite3_value*);
5530int sqlite3_value_numeric_type(sqlite3_value*);
5531int sqlite3_value_nochange(sqlite3_value*);
5532int sqlite3_value_frombind(sqlite3_value*);
5533
5534/*
5535** CAPI3REF: Finding The Subtype Of SQL Values
5536** METHOD: sqlite3_value
5537**
5538** The sqlite3_value_subtype(V) function returns the subtype for
5539** an [application-defined SQL function] argument V.  The subtype
5540** information can be used to pass a limited amount of context from
5541** one SQL function to another.  Use the [sqlite3_result_subtype()]
5542** routine to set the subtype for the return value of an SQL function.
5543*/
5544unsigned int sqlite3_value_subtype(sqlite3_value*);
5545
5546/*
5547** CAPI3REF: Copy And Free SQL Values
5548** METHOD: sqlite3_value
5549**
5550** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
5551** object D and returns a pointer to that copy.  ^The [sqlite3_value] returned
5552** is a [protected sqlite3_value] object even if the input is not.
5553** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
5554** memory allocation fails.
5555**
5556** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
5557** previously obtained from [sqlite3_value_dup()].  ^If V is a NULL pointer
5558** then sqlite3_value_free(V) is a harmless no-op.
5559*/
5560sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
5561void sqlite3_value_free(sqlite3_value*);
5562
5563/*
5564** CAPI3REF: Obtain Aggregate Function Context
5565** METHOD: sqlite3_context
5566**
5567** Implementations of aggregate SQL functions use this
5568** routine to allocate memory for storing their state.
5569**
5570** ^The first time the sqlite3_aggregate_context(C,N) routine is called
5571** for a particular aggregate function, SQLite allocates
5572** N bytes of memory, zeroes out that memory, and returns a pointer
5573** to the new memory. ^On second and subsequent calls to
5574** sqlite3_aggregate_context() for the same aggregate function instance,
5575** the same buffer is returned.  Sqlite3_aggregate_context() is normally
5576** called once for each invocation of the xStep callback and then one
5577** last time when the xFinal callback is invoked.  ^(When no rows match
5578** an aggregate query, the xStep() callback of the aggregate function
5579** implementation is never called and xFinal() is called exactly once.
5580** In those cases, sqlite3_aggregate_context() might be called for the
5581** first time from within xFinal().)^
5582**
5583** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
5584** when first called if N is less than or equal to zero or if a memory
5585** allocate error occurs.
5586**
5587** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
5588** determined by the N parameter on first successful call.  Changing the
5589** value of N in any subsequent call to sqlite3_aggregate_context() within
5590** the same aggregate function instance will not resize the memory
5591** allocation.)^  Within the xFinal callback, it is customary to set
5592** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
5593** pointless memory allocations occur.
5594**
5595** ^SQLite automatically frees the memory allocated by
5596** sqlite3_aggregate_context() when the aggregate query concludes.
5597**
5598** The first parameter must be a copy of the
5599** [sqlite3_context | SQL function context] that is the first parameter
5600** to the xStep or xFinal callback routine that implements the aggregate
5601** function.
5602**
5603** This routine must be called from the same thread in which
5604** the aggregate SQL function is running.
5605*/
5606void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
5607
5608/*
5609** CAPI3REF: User Data For Functions
5610** METHOD: sqlite3_context
5611**
5612** ^The sqlite3_user_data() interface returns a copy of
5613** the pointer that was the pUserData parameter (the 5th parameter)
5614** of the [sqlite3_create_function()]
5615** and [sqlite3_create_function16()] routines that originally
5616** registered the application defined function.
5617**
5618** This routine must be called from the same thread in which
5619** the application-defined function is running.
5620*/
5621void *sqlite3_user_data(sqlite3_context*);
5622
5623/*
5624** CAPI3REF: Database Connection For Functions
5625** METHOD: sqlite3_context
5626**
5627** ^The sqlite3_context_db_handle() interface returns a copy of
5628** the pointer to the [database connection] (the 1st parameter)
5629** of the [sqlite3_create_function()]
5630** and [sqlite3_create_function16()] routines that originally
5631** registered the application defined function.
5632*/
5633sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
5634
5635/*
5636** CAPI3REF: Function Auxiliary Data
5637** METHOD: sqlite3_context
5638**
5639** These functions may be used by (non-aggregate) SQL functions to
5640** associate metadata with argument values. If the same value is passed to
5641** multiple invocations of the same SQL function during query execution, under
5642** some circumstances the associated metadata may be preserved.  An example
5643** of where this might be useful is in a regular-expression matching
5644** function. The compiled version of the regular expression can be stored as
5645** metadata associated with the pattern string.
5646** Then as long as the pattern string remains the same,
5647** the compiled regular expression can be reused on multiple
5648** invocations of the same function.
5649**
5650** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata
5651** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
5652** value to the application-defined function.  ^N is zero for the left-most
5653** function argument.  ^If there is no metadata
5654** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
5655** returns a NULL pointer.
5656**
5657** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
5658** argument of the application-defined function.  ^Subsequent
5659** calls to sqlite3_get_auxdata(C,N) return P from the most recent
5660** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
5661** NULL if the metadata has been discarded.
5662** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
5663** SQLite will invoke the destructor function X with parameter P exactly
5664** once, when the metadata is discarded.
5665** SQLite is free to discard the metadata at any time, including: <ul>
5666** <li> ^(when the corresponding function parameter changes)^, or
5667** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
5668**      SQL statement)^, or
5669** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
5670**       parameter)^, or
5671** <li> ^(during the original sqlite3_set_auxdata() call when a memory
5672**      allocation error occurs.)^ </ul>
5673**
5674** Note the last bullet in particular.  The destructor X in
5675** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
5676** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
5677** should be called near the end of the function implementation and the
5678** function implementation should not make any use of P after
5679** sqlite3_set_auxdata() has been called.
5680**
5681** ^(In practice, metadata is preserved between function calls for
5682** function parameters that are compile-time constants, including literal
5683** values and [parameters] and expressions composed from the same.)^
5684**
5685** The value of the N parameter to these interfaces should be non-negative.
5686** Future enhancements may make use of negative N values to define new
5687** kinds of function caching behavior.
5688**
5689** These routines must be called from the same thread in which
5690** the SQL function is running.
5691*/
5692void *sqlite3_get_auxdata(sqlite3_context*, int N);
5693void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
5694
5695
5696/*
5697** CAPI3REF: Constants Defining Special Destructor Behavior
5698**
5699** These are special values for the destructor that is passed in as the
5700** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
5701** argument is SQLITE_STATIC, it means that the content pointer is constant
5702** and will never change.  It does not need to be destroyed.  ^The
5703** SQLITE_TRANSIENT value means that the content will likely change in
5704** the near future and that SQLite should make its own private copy of
5705** the content before returning.
5706**
5707** The typedef is necessary to work around problems in certain
5708** C++ compilers.
5709*/
5710typedef void (*sqlite3_destructor_type)(void*);
5711#define SQLITE_STATIC      ((sqlite3_destructor_type)0)
5712#define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
5713
5714/*
5715** CAPI3REF: Setting The Result Of An SQL Function
5716** METHOD: sqlite3_context
5717**
5718** These routines are used by the xFunc or xFinal callbacks that
5719** implement SQL functions and aggregates.  See
5720** [sqlite3_create_function()] and [sqlite3_create_function16()]
5721** for additional information.
5722**
5723** These functions work very much like the [parameter binding] family of
5724** functions used to bind values to host parameters in prepared statements.
5725** Refer to the [SQL parameter] documentation for additional information.
5726**
5727** ^The sqlite3_result_blob() interface sets the result from
5728** an application-defined function to be the BLOB whose content is pointed
5729** to by the second parameter and which is N bytes long where N is the
5730** third parameter.
5731**
5732** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
5733** interfaces set the result of the application-defined function to be
5734** a BLOB containing all zero bytes and N bytes in size.
5735**
5736** ^The sqlite3_result_double() interface sets the result from
5737** an application-defined function to be a floating point value specified
5738** by its 2nd argument.
5739**
5740** ^The sqlite3_result_error() and sqlite3_result_error16() functions
5741** cause the implemented SQL function to throw an exception.
5742** ^SQLite uses the string pointed to by the
5743** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
5744** as the text of an error message.  ^SQLite interprets the error
5745** message string from sqlite3_result_error() as UTF-8. ^SQLite
5746** interprets the string from sqlite3_result_error16() as UTF-16 using
5747** the same [byte-order determination rules] as [sqlite3_bind_text16()].
5748** ^If the third parameter to sqlite3_result_error()
5749** or sqlite3_result_error16() is negative then SQLite takes as the error
5750** message all text up through the first zero character.
5751** ^If the third parameter to sqlite3_result_error() or
5752** sqlite3_result_error16() is non-negative then SQLite takes that many
5753** bytes (not characters) from the 2nd parameter as the error message.
5754** ^The sqlite3_result_error() and sqlite3_result_error16()
5755** routines make a private copy of the error message text before
5756** they return.  Hence, the calling function can deallocate or
5757** modify the text after they return without harm.
5758** ^The sqlite3_result_error_code() function changes the error code
5759** returned by SQLite as a result of an error in a function.  ^By default,
5760** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
5761** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
5762**
5763** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
5764** error indicating that a string or BLOB is too long to represent.
5765**
5766** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
5767** error indicating that a memory allocation failed.
5768**
5769** ^The sqlite3_result_int() interface sets the return value
5770** of the application-defined function to be the 32-bit signed integer
5771** value given in the 2nd argument.
5772** ^The sqlite3_result_int64() interface sets the return value
5773** of the application-defined function to be the 64-bit signed integer
5774** value given in the 2nd argument.
5775**
5776** ^The sqlite3_result_null() interface sets the return value
5777** of the application-defined function to be NULL.
5778**
5779** ^The sqlite3_result_text(), sqlite3_result_text16(),
5780** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
5781** set the return value of the application-defined function to be
5782** a text string which is represented as UTF-8, UTF-16 native byte order,
5783** UTF-16 little endian, or UTF-16 big endian, respectively.
5784** ^The sqlite3_result_text64() interface sets the return value of an
5785** application-defined function to be a text string in an encoding
5786** specified by the fifth (and last) parameter, which must be one
5787** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
5788** ^SQLite takes the text result from the application from
5789** the 2nd parameter of the sqlite3_result_text* interfaces.
5790** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5791** is negative, then SQLite takes result text from the 2nd parameter
5792** through the first zero character.
5793** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5794** is non-negative, then as many bytes (not characters) of the text
5795** pointed to by the 2nd parameter are taken as the application-defined
5796** function result.  If the 3rd parameter is non-negative, then it
5797** must be the byte offset into the string where the NUL terminator would
5798** appear if the string where NUL terminated.  If any NUL characters occur
5799** in the string at a byte offset that is less than the value of the 3rd
5800** parameter, then the resulting string will contain embedded NULs and the
5801** result of expressions operating on strings with embedded NULs is undefined.
5802** ^If the 4th parameter to the sqlite3_result_text* interfaces
5803** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
5804** function as the destructor on the text or BLOB result when it has
5805** finished using that result.
5806** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
5807** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
5808** assumes that the text or BLOB result is in constant space and does not
5809** copy the content of the parameter nor call a destructor on the content
5810** when it has finished using that result.
5811** ^If the 4th parameter to the sqlite3_result_text* interfaces
5812** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
5813** then SQLite makes a copy of the result into space obtained
5814** from [sqlite3_malloc()] before it returns.
5815**
5816** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and
5817** sqlite3_result_text16be() routines, and for sqlite3_result_text64()
5818** when the encoding is not UTF8, if the input UTF16 begins with a
5819** byte-order mark (BOM, U+FEFF) then the BOM is removed from the
5820** string and the rest of the string is interpreted according to the
5821** byte-order specified by the BOM.  ^The byte-order specified by
5822** the BOM at the beginning of the text overrides the byte-order
5823** specified by the interface procedure.  ^So, for example, if
5824** sqlite3_result_text16le() is invoked with text that begins
5825** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the
5826** first two bytes of input are skipped and the remaining input
5827** is interpreted as UTF16BE text.
5828**
5829** ^For UTF16 input text to the sqlite3_result_text16(),
5830** sqlite3_result_text16be(), sqlite3_result_text16le(), and
5831** sqlite3_result_text64() routines, if the text contains invalid
5832** UTF16 characters, the invalid characters might be converted
5833** into the unicode replacement character, U+FFFD.
5834**
5835** ^The sqlite3_result_value() interface sets the result of
5836** the application-defined function to be a copy of the
5837** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
5838** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
5839** so that the [sqlite3_value] specified in the parameter may change or
5840** be deallocated after sqlite3_result_value() returns without harm.
5841** ^A [protected sqlite3_value] object may always be used where an
5842** [unprotected sqlite3_value] object is required, so either
5843** kind of [sqlite3_value] object can be used with this interface.
5844**
5845** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
5846** SQL NULL value, just like [sqlite3_result_null(C)], except that it
5847** also associates the host-language pointer P or type T with that
5848** NULL value such that the pointer can be retrieved within an
5849** [application-defined SQL function] using [sqlite3_value_pointer()].
5850** ^If the D parameter is not NULL, then it is a pointer to a destructor
5851** for the P parameter.  ^SQLite invokes D with P as its only argument
5852** when SQLite is finished with P.  The T parameter should be a static
5853** string and preferably a string literal. The sqlite3_result_pointer()
5854** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5855**
5856** If these routines are called from within the different thread
5857** than the one containing the application-defined function that received
5858** the [sqlite3_context] pointer, the results are undefined.
5859*/
5860void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
5861void sqlite3_result_blob64(sqlite3_context*,const void*,
5862                           sqlite3_uint64,void(*)(void*));
5863void sqlite3_result_double(sqlite3_context*, double);
5864void sqlite3_result_error(sqlite3_context*, const char*, int);
5865void sqlite3_result_error16(sqlite3_context*, const void*, int);
5866void sqlite3_result_error_toobig(sqlite3_context*);
5867void sqlite3_result_error_nomem(sqlite3_context*);
5868void sqlite3_result_error_code(sqlite3_context*, int);
5869void sqlite3_result_int(sqlite3_context*, int);
5870void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
5871void sqlite3_result_null(sqlite3_context*);
5872void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
5873void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
5874                           void(*)(void*), unsigned char encoding);
5875void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
5876void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
5877void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
5878void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
5879void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
5880void sqlite3_result_zeroblob(sqlite3_context*, int n);
5881int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
5882
5883
5884/*
5885** CAPI3REF: Setting The Subtype Of An SQL Function
5886** METHOD: sqlite3_context
5887**
5888** The sqlite3_result_subtype(C,T) function causes the subtype of
5889** the result from the [application-defined SQL function] with
5890** [sqlite3_context] C to be the value T.  Only the lower 8 bits
5891** of the subtype T are preserved in current versions of SQLite;
5892** higher order bits are discarded.
5893** The number of subtype bytes preserved by SQLite might increase
5894** in future releases of SQLite.
5895*/
5896void sqlite3_result_subtype(sqlite3_context*,unsigned int);
5897
5898/*
5899** CAPI3REF: Define New Collating Sequences
5900** METHOD: sqlite3
5901**
5902** ^These functions add, remove, or modify a [collation] associated
5903** with the [database connection] specified as the first argument.
5904**
5905** ^The name of the collation is a UTF-8 string
5906** for sqlite3_create_collation() and sqlite3_create_collation_v2()
5907** and a UTF-16 string in native byte order for sqlite3_create_collation16().
5908** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
5909** considered to be the same name.
5910**
5911** ^(The third argument (eTextRep) must be one of the constants:
5912** <ul>
5913** <li> [SQLITE_UTF8],
5914** <li> [SQLITE_UTF16LE],
5915** <li> [SQLITE_UTF16BE],
5916** <li> [SQLITE_UTF16], or
5917** <li> [SQLITE_UTF16_ALIGNED].
5918** </ul>)^
5919** ^The eTextRep argument determines the encoding of strings passed
5920** to the collating function callback, xCompare.
5921** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
5922** force strings to be UTF16 with native byte order.
5923** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
5924** on an even byte address.
5925**
5926** ^The fourth argument, pArg, is an application data pointer that is passed
5927** through as the first argument to the collating function callback.
5928**
5929** ^The fifth argument, xCompare, is a pointer to the collating function.
5930** ^Multiple collating functions can be registered using the same name but
5931** with different eTextRep parameters and SQLite will use whichever
5932** function requires the least amount of data transformation.
5933** ^If the xCompare argument is NULL then the collating function is
5934** deleted.  ^When all collating functions having the same name are deleted,
5935** that collation is no longer usable.
5936**
5937** ^The collating function callback is invoked with a copy of the pArg
5938** application data pointer and with two strings in the encoding specified
5939** by the eTextRep argument.  The two integer parameters to the collating
5940** function callback are the length of the two strings, in bytes. The collating
5941** function must return an integer that is negative, zero, or positive
5942** if the first string is less than, equal to, or greater than the second,
5943** respectively.  A collating function must always return the same answer
5944** given the same inputs.  If two or more collating functions are registered
5945** to the same collation name (using different eTextRep values) then all
5946** must give an equivalent answer when invoked with equivalent strings.
5947** The collating function must obey the following properties for all
5948** strings A, B, and C:
5949**
5950** <ol>
5951** <li> If A==B then B==A.
5952** <li> If A==B and B==C then A==C.
5953** <li> If A&lt;B THEN B&gt;A.
5954** <li> If A&lt;B and B&lt;C then A&lt;C.
5955** </ol>
5956**
5957** If a collating function fails any of the above constraints and that
5958** collating function is registered and used, then the behavior of SQLite
5959** is undefined.
5960**
5961** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
5962** with the addition that the xDestroy callback is invoked on pArg when
5963** the collating function is deleted.
5964** ^Collating functions are deleted when they are overridden by later
5965** calls to the collation creation functions or when the
5966** [database connection] is closed using [sqlite3_close()].
5967**
5968** ^The xDestroy callback is <u>not</u> called if the
5969** sqlite3_create_collation_v2() function fails.  Applications that invoke
5970** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
5971** check the return code and dispose of the application data pointer
5972** themselves rather than expecting SQLite to deal with it for them.
5973** This is different from every other SQLite interface.  The inconsistency
5974** is unfortunate but cannot be changed without breaking backwards
5975** compatibility.
5976**
5977** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
5978*/
5979int sqlite3_create_collation(
5980  sqlite3*,
5981  const char *zName,
5982  int eTextRep,
5983  void *pArg,
5984  int(*xCompare)(void*,int,const void*,int,const void*)
5985);
5986int sqlite3_create_collation_v2(
5987  sqlite3*,
5988  const char *zName,
5989  int eTextRep,
5990  void *pArg,
5991  int(*xCompare)(void*,int,const void*,int,const void*),
5992  void(*xDestroy)(void*)
5993);
5994int sqlite3_create_collation16(
5995  sqlite3*,
5996  const void *zName,
5997  int eTextRep,
5998  void *pArg,
5999  int(*xCompare)(void*,int,const void*,int,const void*)
6000);
6001
6002/*
6003** CAPI3REF: Collation Needed Callbacks
6004** METHOD: sqlite3
6005**
6006** ^To avoid having to register all collation sequences before a database
6007** can be used, a single callback function may be registered with the
6008** [database connection] to be invoked whenever an undefined collation
6009** sequence is required.
6010**
6011** ^If the function is registered using the sqlite3_collation_needed() API,
6012** then it is passed the names of undefined collation sequences as strings
6013** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
6014** the names are passed as UTF-16 in machine native byte order.
6015** ^A call to either function replaces the existing collation-needed callback.
6016**
6017** ^(When the callback is invoked, the first argument passed is a copy
6018** of the second argument to sqlite3_collation_needed() or
6019** sqlite3_collation_needed16().  The second argument is the database
6020** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
6021** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
6022** sequence function required.  The fourth parameter is the name of the
6023** required collation sequence.)^
6024**
6025** The callback function should register the desired collation using
6026** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
6027** [sqlite3_create_collation_v2()].
6028*/
6029int sqlite3_collation_needed(
6030  sqlite3*,
6031  void*,
6032  void(*)(void*,sqlite3*,int eTextRep,const char*)
6033);
6034int sqlite3_collation_needed16(
6035  sqlite3*,
6036  void*,
6037  void(*)(void*,sqlite3*,int eTextRep,const void*)
6038);
6039
6040#ifdef SQLITE_ENABLE_CEROD
6041/*
6042** Specify the activation key for a CEROD database.  Unless
6043** activated, none of the CEROD routines will work.
6044*/
6045void sqlite3_activate_cerod(
6046  const char *zPassPhrase        /* Activation phrase */
6047);
6048#endif
6049
6050/*
6051** CAPI3REF: Suspend Execution For A Short Time
6052**
6053** The sqlite3_sleep() function causes the current thread to suspend execution
6054** for at least a number of milliseconds specified in its parameter.
6055**
6056** If the operating system does not support sleep requests with
6057** millisecond time resolution, then the time will be rounded up to
6058** the nearest second. The number of milliseconds of sleep actually
6059** requested from the operating system is returned.
6060**
6061** ^SQLite implements this interface by calling the xSleep()
6062** method of the default [sqlite3_vfs] object.  If the xSleep() method
6063** of the default VFS is not implemented correctly, or not implemented at
6064** all, then the behavior of sqlite3_sleep() may deviate from the description
6065** in the previous paragraphs.
6066*/
6067int sqlite3_sleep(int);
6068
6069/*
6070** CAPI3REF: Name Of The Folder Holding Temporary Files
6071**
6072** ^(If this global variable is made to point to a string which is
6073** the name of a folder (a.k.a. directory), then all temporary files
6074** created by SQLite when using a built-in [sqlite3_vfs | VFS]
6075** will be placed in that directory.)^  ^If this variable
6076** is a NULL pointer, then SQLite performs a search for an appropriate
6077** temporary file directory.
6078**
6079** Applications are strongly discouraged from using this global variable.
6080** It is required to set a temporary folder on Windows Runtime (WinRT).
6081** But for all other platforms, it is highly recommended that applications
6082** neither read nor write this variable.  This global variable is a relic
6083** that exists for backwards compatibility of legacy applications and should
6084** be avoided in new projects.
6085**
6086** It is not safe to read or modify this variable in more than one
6087** thread at a time.  It is not safe to read or modify this variable
6088** if a [database connection] is being used at the same time in a separate
6089** thread.
6090** It is intended that this variable be set once
6091** as part of process initialization and before any SQLite interface
6092** routines have been called and that this variable remain unchanged
6093** thereafter.
6094**
6095** ^The [temp_store_directory pragma] may modify this variable and cause
6096** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
6097** the [temp_store_directory pragma] always assumes that any string
6098** that this variable points to is held in memory obtained from
6099** [sqlite3_malloc] and the pragma may attempt to free that memory
6100** using [sqlite3_free].
6101** Hence, if this variable is modified directly, either it should be
6102** made NULL or made to point to memory obtained from [sqlite3_malloc]
6103** or else the use of the [temp_store_directory pragma] should be avoided.
6104** Except when requested by the [temp_store_directory pragma], SQLite
6105** does not free the memory that sqlite3_temp_directory points to.  If
6106** the application wants that memory to be freed, it must do
6107** so itself, taking care to only do so after all [database connection]
6108** objects have been destroyed.
6109**
6110** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
6111** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
6112** features that require the use of temporary files may fail.  Here is an
6113** example of how to do this using C++ with the Windows Runtime:
6114**
6115** <blockquote><pre>
6116** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
6117** &nbsp;     TemporaryFolder->Path->Data();
6118** char zPathBuf&#91;MAX_PATH + 1&#93;;
6119** memset(zPathBuf, 0, sizeof(zPathBuf));
6120** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
6121** &nbsp;     NULL, NULL);
6122** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
6123** </pre></blockquote>
6124*/
6125SQLITE_EXTERN char *sqlite3_temp_directory;
6126
6127/*
6128** CAPI3REF: Name Of The Folder Holding Database Files
6129**
6130** ^(If this global variable is made to point to a string which is
6131** the name of a folder (a.k.a. directory), then all database files
6132** specified with a relative pathname and created or accessed by
6133** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
6134** to be relative to that directory.)^ ^If this variable is a NULL
6135** pointer, then SQLite assumes that all database files specified
6136** with a relative pathname are relative to the current directory
6137** for the process.  Only the windows VFS makes use of this global
6138** variable; it is ignored by the unix VFS.
6139**
6140** Changing the value of this variable while a database connection is
6141** open can result in a corrupt database.
6142**
6143** It is not safe to read or modify this variable in more than one
6144** thread at a time.  It is not safe to read or modify this variable
6145** if a [database connection] is being used at the same time in a separate
6146** thread.
6147** It is intended that this variable be set once
6148** as part of process initialization and before any SQLite interface
6149** routines have been called and that this variable remain unchanged
6150** thereafter.
6151**
6152** ^The [data_store_directory pragma] may modify this variable and cause
6153** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
6154** the [data_store_directory pragma] always assumes that any string
6155** that this variable points to is held in memory obtained from
6156** [sqlite3_malloc] and the pragma may attempt to free that memory
6157** using [sqlite3_free].
6158** Hence, if this variable is modified directly, either it should be
6159** made NULL or made to point to memory obtained from [sqlite3_malloc]
6160** or else the use of the [data_store_directory pragma] should be avoided.
6161*/
6162SQLITE_EXTERN char *sqlite3_data_directory;
6163
6164/*
6165** CAPI3REF: Win32 Specific Interface
6166**
6167** These interfaces are available only on Windows.  The
6168** [sqlite3_win32_set_directory] interface is used to set the value associated
6169** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
6170** zValue, depending on the value of the type parameter.  The zValue parameter
6171** should be NULL to cause the previous value to be freed via [sqlite3_free];
6172** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
6173** prior to being used.  The [sqlite3_win32_set_directory] interface returns
6174** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
6175** or [SQLITE_NOMEM] if memory could not be allocated.  The value of the
6176** [sqlite3_data_directory] variable is intended to act as a replacement for
6177** the current directory on the sub-platforms of Win32 where that concept is
6178** not present, e.g. WinRT and UWP.  The [sqlite3_win32_set_directory8] and
6179** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
6180** sqlite3_win32_set_directory interface except the string parameter must be
6181** UTF-8 or UTF-16, respectively.
6182*/
6183int sqlite3_win32_set_directory(
6184  unsigned long type, /* Identifier for directory being set or reset */
6185  void *zValue        /* New value for directory being set or reset */
6186);
6187int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
6188int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
6189
6190/*
6191** CAPI3REF: Win32 Directory Types
6192**
6193** These macros are only available on Windows.  They define the allowed values
6194** for the type argument to the [sqlite3_win32_set_directory] interface.
6195*/
6196#define SQLITE_WIN32_DATA_DIRECTORY_TYPE  1
6197#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE  2
6198
6199/*
6200** CAPI3REF: Test For Auto-Commit Mode
6201** KEYWORDS: {autocommit mode}
6202** METHOD: sqlite3
6203**
6204** ^The sqlite3_get_autocommit() interface returns non-zero or
6205** zero if the given database connection is or is not in autocommit mode,
6206** respectively.  ^Autocommit mode is on by default.
6207** ^Autocommit mode is disabled by a [BEGIN] statement.
6208** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
6209**
6210** If certain kinds of errors occur on a statement within a multi-statement
6211** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
6212** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
6213** transaction might be rolled back automatically.  The only way to
6214** find out whether SQLite automatically rolled back the transaction after
6215** an error is to use this function.
6216**
6217** If another thread changes the autocommit status of the database
6218** connection while this routine is running, then the return value
6219** is undefined.
6220*/
6221int sqlite3_get_autocommit(sqlite3*);
6222
6223/*
6224** CAPI3REF: Find The Database Handle Of A Prepared Statement
6225** METHOD: sqlite3_stmt
6226**
6227** ^The sqlite3_db_handle interface returns the [database connection] handle
6228** to which a [prepared statement] belongs.  ^The [database connection]
6229** returned by sqlite3_db_handle is the same [database connection]
6230** that was the first argument
6231** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
6232** create the statement in the first place.
6233*/
6234sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
6235
6236/*
6237** CAPI3REF: Return The Filename For A Database Connection
6238** METHOD: sqlite3
6239**
6240** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename
6241** associated with database N of connection D.
6242** ^If there is no attached database N on the database
6243** connection D, or if database N is a temporary or in-memory database, then
6244** this function will return either a NULL pointer or an empty string.
6245**
6246** ^The string value returned by this routine is owned and managed by
6247** the database connection.  ^The value will be valid until the database N
6248** is [DETACH]-ed or until the database connection closes.
6249**
6250** ^The filename returned by this function is the output of the
6251** xFullPathname method of the [VFS].  ^In other words, the filename
6252** will be an absolute pathname, even if the filename used
6253** to open the database originally was a URI or relative pathname.
6254**
6255** If the filename pointer returned by this routine is not NULL, then it
6256** can be used as the filename input parameter to these routines:
6257** <ul>
6258** <li> [sqlite3_uri_parameter()]
6259** <li> [sqlite3_uri_boolean()]
6260** <li> [sqlite3_uri_int64()]
6261** <li> [sqlite3_filename_database()]
6262** <li> [sqlite3_filename_journal()]
6263** <li> [sqlite3_filename_wal()]
6264** </ul>
6265*/
6266const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
6267
6268/*
6269** CAPI3REF: Determine if a database is read-only
6270** METHOD: sqlite3
6271**
6272** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
6273** of connection D is read-only, 0 if it is read/write, or -1 if N is not
6274** the name of a database on connection D.
6275*/
6276int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
6277
6278/*
6279** CAPI3REF: Determine the transaction state of a database
6280** METHOD: sqlite3
6281**
6282** ^The sqlite3_txn_state(D,S) interface returns the current
6283** [transaction state] of schema S in database connection D.  ^If S is NULL,
6284** then the highest transaction state of any schema on database connection D
6285** is returned.  Transaction states are (in order of lowest to highest):
6286** <ol>
6287** <li value="0"> SQLITE_TXN_NONE
6288** <li value="1"> SQLITE_TXN_READ
6289** <li value="2"> SQLITE_TXN_WRITE
6290** </ol>
6291** ^If the S argument to sqlite3_txn_state(D,S) is not the name of
6292** a valid schema, then -1 is returned.
6293*/
6294int sqlite3_txn_state(sqlite3*,const char *zSchema);
6295
6296/*
6297** CAPI3REF: Allowed return values from [sqlite3_txn_state()]
6298** KEYWORDS: {transaction state}
6299**
6300** These constants define the current transaction state of a database file.
6301** ^The [sqlite3_txn_state(D,S)] interface returns one of these
6302** constants in order to describe the transaction state of schema S
6303** in [database connection] D.
6304**
6305** <dl>
6306** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt>
6307** <dd>The SQLITE_TXN_NONE state means that no transaction is currently
6308** pending.</dd>
6309**
6310** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt>
6311** <dd>The SQLITE_TXN_READ state means that the database is currently
6312** in a read transaction.  Content has been read from the database file
6313** but nothing in the database file has changed.  The transaction state
6314** will advanced to SQLITE_TXN_WRITE if any changes occur and there are
6315** no other conflicting concurrent write transactions.  The transaction
6316** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or
6317** [COMMIT].</dd>
6318**
6319** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt>
6320** <dd>The SQLITE_TXN_WRITE state means that the database is currently
6321** in a write transaction.  Content has been written to the database file
6322** but has not yet committed.  The transaction state will change to
6323** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd>
6324*/
6325#define SQLITE_TXN_NONE  0
6326#define SQLITE_TXN_READ  1
6327#define SQLITE_TXN_WRITE 2
6328
6329/*
6330** CAPI3REF: Find the next prepared statement
6331** METHOD: sqlite3
6332**
6333** ^This interface returns a pointer to the next [prepared statement] after
6334** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
6335** then this interface returns a pointer to the first prepared statement
6336** associated with the database connection pDb.  ^If no prepared statement
6337** satisfies the conditions of this routine, it returns NULL.
6338**
6339** The [database connection] pointer D in a call to
6340** [sqlite3_next_stmt(D,S)] must refer to an open database
6341** connection and in particular must not be a NULL pointer.
6342*/
6343sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
6344
6345/*
6346** CAPI3REF: Commit And Rollback Notification Callbacks
6347** METHOD: sqlite3
6348**
6349** ^The sqlite3_commit_hook() interface registers a callback
6350** function to be invoked whenever a transaction is [COMMIT | committed].
6351** ^Any callback set by a previous call to sqlite3_commit_hook()
6352** for the same database connection is overridden.
6353** ^The sqlite3_rollback_hook() interface registers a callback
6354** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
6355** ^Any callback set by a previous call to sqlite3_rollback_hook()
6356** for the same database connection is overridden.
6357** ^The pArg argument is passed through to the callback.
6358** ^If the callback on a commit hook function returns non-zero,
6359** then the commit is converted into a rollback.
6360**
6361** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
6362** return the P argument from the previous call of the same function
6363** on the same [database connection] D, or NULL for
6364** the first call for each function on D.
6365**
6366** The commit and rollback hook callbacks are not reentrant.
6367** The callback implementation must not do anything that will modify
6368** the database connection that invoked the callback.  Any actions
6369** to modify the database connection must be deferred until after the
6370** completion of the [sqlite3_step()] call that triggered the commit
6371** or rollback hook in the first place.
6372** Note that running any other SQL statements, including SELECT statements,
6373** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
6374** the database connections for the meaning of "modify" in this paragraph.
6375**
6376** ^Registering a NULL function disables the callback.
6377**
6378** ^When the commit hook callback routine returns zero, the [COMMIT]
6379** operation is allowed to continue normally.  ^If the commit hook
6380** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
6381** ^The rollback hook is invoked on a rollback that results from a commit
6382** hook returning non-zero, just as it would be with any other rollback.
6383**
6384** ^For the purposes of this API, a transaction is said to have been
6385** rolled back if an explicit "ROLLBACK" statement is executed, or
6386** an error or constraint causes an implicit rollback to occur.
6387** ^The rollback callback is not invoked if a transaction is
6388** automatically rolled back because the database connection is closed.
6389**
6390** See also the [sqlite3_update_hook()] interface.
6391*/
6392void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
6393void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
6394
6395/*
6396** CAPI3REF: Data Change Notification Callbacks
6397** METHOD: sqlite3
6398**
6399** ^The sqlite3_update_hook() interface registers a callback function
6400** with the [database connection] identified by the first argument
6401** to be invoked whenever a row is updated, inserted or deleted in
6402** a [rowid table].
6403** ^Any callback set by a previous call to this function
6404** for the same database connection is overridden.
6405**
6406** ^The second argument is a pointer to the function to invoke when a
6407** row is updated, inserted or deleted in a rowid table.
6408** ^The first argument to the callback is a copy of the third argument
6409** to sqlite3_update_hook().
6410** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
6411** or [SQLITE_UPDATE], depending on the operation that caused the callback
6412** to be invoked.
6413** ^The third and fourth arguments to the callback contain pointers to the
6414** database and table name containing the affected row.
6415** ^The final callback parameter is the [rowid] of the row.
6416** ^In the case of an update, this is the [rowid] after the update takes place.
6417**
6418** ^(The update hook is not invoked when internal system tables are
6419** modified (i.e. sqlite_sequence).)^
6420** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
6421**
6422** ^In the current implementation, the update hook
6423** is not invoked when conflicting rows are deleted because of an
6424** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
6425** invoked when rows are deleted using the [truncate optimization].
6426** The exceptions defined in this paragraph might change in a future
6427** release of SQLite.
6428**
6429** The update hook implementation must not do anything that will modify
6430** the database connection that invoked the update hook.  Any actions
6431** to modify the database connection must be deferred until after the
6432** completion of the [sqlite3_step()] call that triggered the update hook.
6433** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
6434** database connections for the meaning of "modify" in this paragraph.
6435**
6436** ^The sqlite3_update_hook(D,C,P) function
6437** returns the P argument from the previous call
6438** on the same [database connection] D, or NULL for
6439** the first call on D.
6440**
6441** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
6442** and [sqlite3_preupdate_hook()] interfaces.
6443*/
6444void *sqlite3_update_hook(
6445  sqlite3*,
6446  void(*)(void *,int ,char const *,char const *,sqlite3_int64),
6447  void*
6448);
6449
6450/*
6451** CAPI3REF: Enable Or Disable Shared Pager Cache
6452**
6453** ^(This routine enables or disables the sharing of the database cache
6454** and schema data structures between [database connection | connections]
6455** to the same database. Sharing is enabled if the argument is true
6456** and disabled if the argument is false.)^
6457**
6458** ^Cache sharing is enabled and disabled for an entire process.
6459** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
6460** In prior versions of SQLite,
6461** sharing was enabled or disabled for each thread separately.
6462**
6463** ^(The cache sharing mode set by this interface effects all subsequent
6464** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
6465** Existing database connections continue to use the sharing mode
6466** that was in effect at the time they were opened.)^
6467**
6468** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
6469** successfully.  An [error code] is returned otherwise.)^
6470**
6471** ^Shared cache is disabled by default. It is recommended that it stay
6472** that way.  In other words, do not use this routine.  This interface
6473** continues to be provided for historical compatibility, but its use is
6474** discouraged.  Any use of shared cache is discouraged.  If shared cache
6475** must be used, it is recommended that shared cache only be enabled for
6476** individual database connections using the [sqlite3_open_v2()] interface
6477** with the [SQLITE_OPEN_SHAREDCACHE] flag.
6478**
6479** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
6480** and will always return SQLITE_MISUSE. On those systems,
6481** shared cache mode should be enabled per-database connection via
6482** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
6483**
6484** This interface is threadsafe on processors where writing a
6485** 32-bit integer is atomic.
6486**
6487** See Also:  [SQLite Shared-Cache Mode]
6488*/
6489int sqlite3_enable_shared_cache(int);
6490
6491/*
6492** CAPI3REF: Attempt To Free Heap Memory
6493**
6494** ^The sqlite3_release_memory() interface attempts to free N bytes
6495** of heap memory by deallocating non-essential memory allocations
6496** held by the database library.   Memory used to cache database
6497** pages to improve performance is an example of non-essential memory.
6498** ^sqlite3_release_memory() returns the number of bytes actually freed,
6499** which might be more or less than the amount requested.
6500** ^The sqlite3_release_memory() routine is a no-op returning zero
6501** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
6502**
6503** See also: [sqlite3_db_release_memory()]
6504*/
6505int sqlite3_release_memory(int);
6506
6507/*
6508** CAPI3REF: Free Memory Used By A Database Connection
6509** METHOD: sqlite3
6510**
6511** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
6512** memory as possible from database connection D. Unlike the
6513** [sqlite3_release_memory()] interface, this interface is in effect even
6514** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
6515** omitted.
6516**
6517** See also: [sqlite3_release_memory()]
6518*/
6519int sqlite3_db_release_memory(sqlite3*);
6520
6521/*
6522** CAPI3REF: Impose A Limit On Heap Size
6523**
6524** These interfaces impose limits on the amount of heap memory that will be
6525** by all database connections within a single process.
6526**
6527** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
6528** soft limit on the amount of heap memory that may be allocated by SQLite.
6529** ^SQLite strives to keep heap memory utilization below the soft heap
6530** limit by reducing the number of pages held in the page cache
6531** as heap memory usages approaches the limit.
6532** ^The soft heap limit is "soft" because even though SQLite strives to stay
6533** below the limit, it will exceed the limit rather than generate
6534** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
6535** is advisory only.
6536**
6537** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of
6538** N bytes on the amount of memory that will be allocated.  ^The
6539** sqlite3_hard_heap_limit64(N) interface is similar to
6540** sqlite3_soft_heap_limit64(N) except that memory allocations will fail
6541** when the hard heap limit is reached.
6542**
6543** ^The return value from both sqlite3_soft_heap_limit64() and
6544** sqlite3_hard_heap_limit64() is the size of
6545** the heap limit prior to the call, or negative in the case of an
6546** error.  ^If the argument N is negative
6547** then no change is made to the heap limit.  Hence, the current
6548** size of heap limits can be determined by invoking
6549** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1).
6550**
6551** ^Setting the heap limits to zero disables the heap limiter mechanism.
6552**
6553** ^The soft heap limit may not be greater than the hard heap limit.
6554** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N)
6555** is invoked with a value of N that is greater than the hard heap limit,
6556** the the soft heap limit is set to the value of the hard heap limit.
6557** ^The soft heap limit is automatically enabled whenever the hard heap
6558** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and
6559** the soft heap limit is outside the range of 1..N, then the soft heap
6560** limit is set to N.  ^Invoking sqlite3_soft_heap_limit64(0) when the
6561** hard heap limit is enabled makes the soft heap limit equal to the
6562** hard heap limit.
6563**
6564** The memory allocation limits can also be adjusted using
6565** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit].
6566**
6567** ^(The heap limits are not enforced in the current implementation
6568** if one or more of following conditions are true:
6569**
6570** <ul>
6571** <li> The limit value is set to zero.
6572** <li> Memory accounting is disabled using a combination of the
6573**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
6574**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
6575** <li> An alternative page cache implementation is specified using
6576**      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
6577** <li> The page cache allocates from its own memory pool supplied
6578**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
6579**      from the heap.
6580** </ul>)^
6581**
6582** The circumstances under which SQLite will enforce the heap limits may
6583** changes in future releases of SQLite.
6584*/
6585sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
6586sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N);
6587
6588/*
6589** CAPI3REF: Deprecated Soft Heap Limit Interface
6590** DEPRECATED
6591**
6592** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
6593** interface.  This routine is provided for historical compatibility
6594** only.  All new applications should use the
6595** [sqlite3_soft_heap_limit64()] interface rather than this one.
6596*/
6597SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
6598
6599
6600/*
6601** CAPI3REF: Extract Metadata About A Column Of A Table
6602** METHOD: sqlite3
6603**
6604** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
6605** information about column C of table T in database D
6606** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
6607** interface returns SQLITE_OK and fills in the non-NULL pointers in
6608** the final five arguments with appropriate values if the specified
6609** column exists.  ^The sqlite3_table_column_metadata() interface returns
6610** SQLITE_ERROR if the specified column does not exist.
6611** ^If the column-name parameter to sqlite3_table_column_metadata() is a
6612** NULL pointer, then this routine simply checks for the existence of the
6613** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
6614** does not.  If the table name parameter T in a call to
6615** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
6616** undefined behavior.
6617**
6618** ^The column is identified by the second, third and fourth parameters to
6619** this function. ^(The second parameter is either the name of the database
6620** (i.e. "main", "temp", or an attached database) containing the specified
6621** table or NULL.)^ ^If it is NULL, then all attached databases are searched
6622** for the table using the same algorithm used by the database engine to
6623** resolve unqualified table references.
6624**
6625** ^The third and fourth parameters to this function are the table and column
6626** name of the desired column, respectively.
6627**
6628** ^Metadata is returned by writing to the memory locations passed as the 5th
6629** and subsequent parameters to this function. ^Any of these arguments may be
6630** NULL, in which case the corresponding element of metadata is omitted.
6631**
6632** ^(<blockquote>
6633** <table border="1">
6634** <tr><th> Parameter <th> Output<br>Type <th>  Description
6635**
6636** <tr><td> 5th <td> const char* <td> Data type
6637** <tr><td> 6th <td> const char* <td> Name of default collation sequence
6638** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
6639** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
6640** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
6641** </table>
6642** </blockquote>)^
6643**
6644** ^The memory pointed to by the character pointers returned for the
6645** declaration type and collation sequence is valid until the next
6646** call to any SQLite API function.
6647**
6648** ^If the specified table is actually a view, an [error code] is returned.
6649**
6650** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
6651** is not a [WITHOUT ROWID] table and an
6652** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
6653** parameters are set for the explicitly declared column. ^(If there is no
6654** [INTEGER PRIMARY KEY] column, then the outputs
6655** for the [rowid] are set as follows:
6656**
6657** <pre>
6658**     data type: "INTEGER"
6659**     collation sequence: "BINARY"
6660**     not null: 0
6661**     primary key: 1
6662**     auto increment: 0
6663** </pre>)^
6664**
6665** ^This function causes all database schemas to be read from disk and
6666** parsed, if that has not already been done, and returns an error if
6667** any errors are encountered while loading the schema.
6668*/
6669int sqlite3_table_column_metadata(
6670  sqlite3 *db,                /* Connection handle */
6671  const char *zDbName,        /* Database name or NULL */
6672  const char *zTableName,     /* Table name */
6673  const char *zColumnName,    /* Column name */
6674  char const **pzDataType,    /* OUTPUT: Declared data type */
6675  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
6676  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
6677  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
6678  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
6679);
6680
6681/*
6682** CAPI3REF: Load An Extension
6683** METHOD: sqlite3
6684**
6685** ^This interface loads an SQLite extension library from the named file.
6686**
6687** ^The sqlite3_load_extension() interface attempts to load an
6688** [SQLite extension] library contained in the file zFile.  If
6689** the file cannot be loaded directly, attempts are made to load
6690** with various operating-system specific extensions added.
6691** So for example, if "samplelib" cannot be loaded, then names like
6692** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
6693** be tried also.
6694**
6695** ^The entry point is zProc.
6696** ^(zProc may be 0, in which case SQLite will try to come up with an
6697** entry point name on its own.  It first tries "sqlite3_extension_init".
6698** If that does not work, it constructs a name "sqlite3_X_init" where the
6699** X is consists of the lower-case equivalent of all ASCII alphabetic
6700** characters in the filename from the last "/" to the first following
6701** "." and omitting any initial "lib".)^
6702** ^The sqlite3_load_extension() interface returns
6703** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
6704** ^If an error occurs and pzErrMsg is not 0, then the
6705** [sqlite3_load_extension()] interface shall attempt to
6706** fill *pzErrMsg with error message text stored in memory
6707** obtained from [sqlite3_malloc()]. The calling function
6708** should free this memory by calling [sqlite3_free()].
6709**
6710** ^Extension loading must be enabled using
6711** [sqlite3_enable_load_extension()] or
6712** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
6713** prior to calling this API,
6714** otherwise an error will be returned.
6715**
6716** <b>Security warning:</b> It is recommended that the
6717** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
6718** interface.  The use of the [sqlite3_enable_load_extension()] interface
6719** should be avoided.  This will keep the SQL function [load_extension()]
6720** disabled and prevent SQL injections from giving attackers
6721** access to extension loading capabilities.
6722**
6723** See also the [load_extension() SQL function].
6724*/
6725int sqlite3_load_extension(
6726  sqlite3 *db,          /* Load the extension into this database connection */
6727  const char *zFile,    /* Name of the shared library containing extension */
6728  const char *zProc,    /* Entry point.  Derived from zFile if 0 */
6729  char **pzErrMsg       /* Put error message here if not 0 */
6730);
6731
6732/*
6733** CAPI3REF: Enable Or Disable Extension Loading
6734** METHOD: sqlite3
6735**
6736** ^So as not to open security holes in older applications that are
6737** unprepared to deal with [extension loading], and as a means of disabling
6738** [extension loading] while evaluating user-entered SQL, the following API
6739** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
6740**
6741** ^Extension loading is off by default.
6742** ^Call the sqlite3_enable_load_extension() routine with onoff==1
6743** to turn extension loading on and call it with onoff==0 to turn
6744** it back off again.
6745**
6746** ^This interface enables or disables both the C-API
6747** [sqlite3_load_extension()] and the SQL function [load_extension()].
6748** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
6749** to enable or disable only the C-API.)^
6750**
6751** <b>Security warning:</b> It is recommended that extension loading
6752** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
6753** rather than this interface, so the [load_extension()] SQL function
6754** remains disabled. This will prevent SQL injections from giving attackers
6755** access to extension loading capabilities.
6756*/
6757int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
6758
6759/*
6760** CAPI3REF: Automatically Load Statically Linked Extensions
6761**
6762** ^This interface causes the xEntryPoint() function to be invoked for
6763** each new [database connection] that is created.  The idea here is that
6764** xEntryPoint() is the entry point for a statically linked [SQLite extension]
6765** that is to be automatically loaded into all new database connections.
6766**
6767** ^(Even though the function prototype shows that xEntryPoint() takes
6768** no arguments and returns void, SQLite invokes xEntryPoint() with three
6769** arguments and expects an integer result as if the signature of the
6770** entry point where as follows:
6771**
6772** <blockquote><pre>
6773** &nbsp;  int xEntryPoint(
6774** &nbsp;    sqlite3 *db,
6775** &nbsp;    const char **pzErrMsg,
6776** &nbsp;    const struct sqlite3_api_routines *pThunk
6777** &nbsp;  );
6778** </pre></blockquote>)^
6779**
6780** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
6781** point to an appropriate error message (obtained from [sqlite3_mprintf()])
6782** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
6783** is NULL before calling the xEntryPoint().  ^SQLite will invoke
6784** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
6785** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
6786** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
6787**
6788** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
6789** on the list of automatic extensions is a harmless no-op. ^No entry point
6790** will be called more than once for each database connection that is opened.
6791**
6792** See also: [sqlite3_reset_auto_extension()]
6793** and [sqlite3_cancel_auto_extension()]
6794*/
6795int sqlite3_auto_extension(void(*xEntryPoint)(void));
6796
6797/*
6798** CAPI3REF: Cancel Automatic Extension Loading
6799**
6800** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
6801** initialization routine X that was registered using a prior call to
6802** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
6803** routine returns 1 if initialization routine X was successfully
6804** unregistered and it returns 0 if X was not on the list of initialization
6805** routines.
6806*/
6807int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
6808
6809/*
6810** CAPI3REF: Reset Automatic Extension Loading
6811**
6812** ^This interface disables all automatic extensions previously
6813** registered using [sqlite3_auto_extension()].
6814*/
6815void sqlite3_reset_auto_extension(void);
6816
6817/*
6818** The interface to the virtual-table mechanism is currently considered
6819** to be experimental.  The interface might change in incompatible ways.
6820** If this is a problem for you, do not use the interface at this time.
6821**
6822** When the virtual-table mechanism stabilizes, we will declare the
6823** interface fixed, support it indefinitely, and remove this comment.
6824*/
6825
6826/*
6827** Structures used by the virtual table interface
6828*/
6829typedef struct sqlite3_vtab sqlite3_vtab;
6830typedef struct sqlite3_index_info sqlite3_index_info;
6831typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
6832typedef struct sqlite3_module sqlite3_module;
6833
6834/*
6835** CAPI3REF: Virtual Table Object
6836** KEYWORDS: sqlite3_module {virtual table module}
6837**
6838** This structure, sometimes called a "virtual table module",
6839** defines the implementation of a [virtual table].
6840** This structure consists mostly of methods for the module.
6841**
6842** ^A virtual table module is created by filling in a persistent
6843** instance of this structure and passing a pointer to that instance
6844** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
6845** ^The registration remains valid until it is replaced by a different
6846** module or until the [database connection] closes.  The content
6847** of this structure must not change while it is registered with
6848** any database connection.
6849*/
6850struct sqlite3_module {
6851  int iVersion;
6852  int (*xCreate)(sqlite3*, void *pAux,
6853               int argc, const char *const*argv,
6854               sqlite3_vtab **ppVTab, char**);
6855  int (*xConnect)(sqlite3*, void *pAux,
6856               int argc, const char *const*argv,
6857               sqlite3_vtab **ppVTab, char**);
6858  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
6859  int (*xDisconnect)(sqlite3_vtab *pVTab);
6860  int (*xDestroy)(sqlite3_vtab *pVTab);
6861  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
6862  int (*xClose)(sqlite3_vtab_cursor*);
6863  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
6864                int argc, sqlite3_value **argv);
6865  int (*xNext)(sqlite3_vtab_cursor*);
6866  int (*xEof)(sqlite3_vtab_cursor*);
6867  int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
6868  int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
6869  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
6870  int (*xBegin)(sqlite3_vtab *pVTab);
6871  int (*xSync)(sqlite3_vtab *pVTab);
6872  int (*xCommit)(sqlite3_vtab *pVTab);
6873  int (*xRollback)(sqlite3_vtab *pVTab);
6874  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
6875                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
6876                       void **ppArg);
6877  int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
6878  /* The methods above are in version 1 of the sqlite_module object. Those
6879  ** below are for version 2 and greater. */
6880  int (*xSavepoint)(sqlite3_vtab *pVTab, int);
6881  int (*xRelease)(sqlite3_vtab *pVTab, int);
6882  int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
6883  /* The methods above are in versions 1 and 2 of the sqlite_module object.
6884  ** Those below are for version 3 and greater. */
6885  int (*xShadowName)(const char*);
6886};
6887
6888/*
6889** CAPI3REF: Virtual Table Indexing Information
6890** KEYWORDS: sqlite3_index_info
6891**
6892** The sqlite3_index_info structure and its substructures is used as part
6893** of the [virtual table] interface to
6894** pass information into and receive the reply from the [xBestIndex]
6895** method of a [virtual table module].  The fields under **Inputs** are the
6896** inputs to xBestIndex and are read-only.  xBestIndex inserts its
6897** results into the **Outputs** fields.
6898**
6899** ^(The aConstraint[] array records WHERE clause constraints of the form:
6900**
6901** <blockquote>column OP expr</blockquote>
6902**
6903** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
6904** stored in aConstraint[].op using one of the
6905** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
6906** ^(The index of the column is stored in
6907** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
6908** expr on the right-hand side can be evaluated (and thus the constraint
6909** is usable) and false if it cannot.)^
6910**
6911** ^The optimizer automatically inverts terms of the form "expr OP column"
6912** and makes other simplifications to the WHERE clause in an attempt to
6913** get as many WHERE clause terms into the form shown above as possible.
6914** ^The aConstraint[] array only reports WHERE clause terms that are
6915** relevant to the particular virtual table being queried.
6916**
6917** ^Information about the ORDER BY clause is stored in aOrderBy[].
6918** ^Each term of aOrderBy records a column of the ORDER BY clause.
6919**
6920** The colUsed field indicates which columns of the virtual table may be
6921** required by the current scan. Virtual table columns are numbered from
6922** zero in the order in which they appear within the CREATE TABLE statement
6923** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
6924** the corresponding bit is set within the colUsed mask if the column may be
6925** required by SQLite. If the table has at least 64 columns and any column
6926** to the right of the first 63 is required, then bit 63 of colUsed is also
6927** set. In other words, column iCol may be required if the expression
6928** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
6929** non-zero.
6930**
6931** The [xBestIndex] method must fill aConstraintUsage[] with information
6932** about what parameters to pass to xFilter.  ^If argvIndex>0 then
6933** the right-hand side of the corresponding aConstraint[] is evaluated
6934** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
6935** is true, then the constraint is assumed to be fully handled by the
6936** virtual table and might not be checked again by the byte code.)^ ^(The
6937** aConstraintUsage[].omit flag is an optimization hint. When the omit flag
6938** is left in its default setting of false, the constraint will always be
6939** checked separately in byte code.  If the omit flag is change to true, then
6940** the constraint may or may not be checked in byte code.  In other words,
6941** when the omit flag is true there is no guarantee that the constraint will
6942** not be checked again using byte code.)^
6943**
6944** ^The idxNum and idxPtr values are recorded and passed into the
6945** [xFilter] method.
6946** ^[sqlite3_free()] is used to free idxPtr if and only if
6947** needToFreeIdxPtr is true.
6948**
6949** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
6950** the correct order to satisfy the ORDER BY clause so that no separate
6951** sorting step is required.
6952**
6953** ^The estimatedCost value is an estimate of the cost of a particular
6954** strategy. A cost of N indicates that the cost of the strategy is similar
6955** to a linear scan of an SQLite table with N rows. A cost of log(N)
6956** indicates that the expense of the operation is similar to that of a
6957** binary search on a unique indexed field of an SQLite table with N rows.
6958**
6959** ^The estimatedRows value is an estimate of the number of rows that
6960** will be returned by the strategy.
6961**
6962** The xBestIndex method may optionally populate the idxFlags field with a
6963** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
6964** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
6965** assumes that the strategy may visit at most one row.
6966**
6967** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
6968** SQLite also assumes that if a call to the xUpdate() method is made as
6969** part of the same statement to delete or update a virtual table row and the
6970** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
6971** any database changes. In other words, if the xUpdate() returns
6972** SQLITE_CONSTRAINT, the database contents must be exactly as they were
6973** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
6974** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
6975** the xUpdate method are automatically rolled back by SQLite.
6976**
6977** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
6978** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
6979** If a virtual table extension is
6980** used with an SQLite version earlier than 3.8.2, the results of attempting
6981** to read or write the estimatedRows field are undefined (but are likely
6982** to include crashing the application). The estimatedRows field should
6983** therefore only be used if [sqlite3_libversion_number()] returns a
6984** value greater than or equal to 3008002. Similarly, the idxFlags field
6985** was added for [version 3.9.0] ([dateof:3.9.0]).
6986** It may therefore only be used if
6987** sqlite3_libversion_number() returns a value greater than or equal to
6988** 3009000.
6989*/
6990struct sqlite3_index_info {
6991  /* Inputs */
6992  int nConstraint;           /* Number of entries in aConstraint */
6993  struct sqlite3_index_constraint {
6994     int iColumn;              /* Column constrained.  -1 for ROWID */
6995     unsigned char op;         /* Constraint operator */
6996     unsigned char usable;     /* True if this constraint is usable */
6997     int iTermOffset;          /* Used internally - xBestIndex should ignore */
6998  } *aConstraint;            /* Table of WHERE clause constraints */
6999  int nOrderBy;              /* Number of terms in the ORDER BY clause */
7000  struct sqlite3_index_orderby {
7001     int iColumn;              /* Column number */
7002     unsigned char desc;       /* True for DESC.  False for ASC. */
7003  } *aOrderBy;               /* The ORDER BY clause */
7004  /* Outputs */
7005  struct sqlite3_index_constraint_usage {
7006    int argvIndex;           /* if >0, constraint is part of argv to xFilter */
7007    unsigned char omit;      /* Do not code a test for this constraint */
7008  } *aConstraintUsage;
7009  int idxNum;                /* Number used to identify the index */
7010  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
7011  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
7012  int orderByConsumed;       /* True if output is already ordered */
7013  double estimatedCost;           /* Estimated cost of using this index */
7014  /* Fields below are only available in SQLite 3.8.2 and later */
7015  sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
7016  /* Fields below are only available in SQLite 3.9.0 and later */
7017  int idxFlags;              /* Mask of SQLITE_INDEX_SCAN_* flags */
7018  /* Fields below are only available in SQLite 3.10.0 and later */
7019  sqlite3_uint64 colUsed;    /* Input: Mask of columns used by statement */
7020};
7021
7022/*
7023** CAPI3REF: Virtual Table Scan Flags
7024**
7025** Virtual table implementations are allowed to set the
7026** [sqlite3_index_info].idxFlags field to some combination of
7027** these bits.
7028*/
7029#define SQLITE_INDEX_SCAN_UNIQUE      1     /* Scan visits at most 1 row */
7030
7031/*
7032** CAPI3REF: Virtual Table Constraint Operator Codes
7033**
7034** These macros define the allowed values for the
7035** [sqlite3_index_info].aConstraint[].op field.  Each value represents
7036** an operator that is part of a constraint term in the wHERE clause of
7037** a query that uses a [virtual table].
7038*/
7039#define SQLITE_INDEX_CONSTRAINT_EQ         2
7040#define SQLITE_INDEX_CONSTRAINT_GT         4
7041#define SQLITE_INDEX_CONSTRAINT_LE         8
7042#define SQLITE_INDEX_CONSTRAINT_LT        16
7043#define SQLITE_INDEX_CONSTRAINT_GE        32
7044#define SQLITE_INDEX_CONSTRAINT_MATCH     64
7045#define SQLITE_INDEX_CONSTRAINT_LIKE      65
7046#define SQLITE_INDEX_CONSTRAINT_GLOB      66
7047#define SQLITE_INDEX_CONSTRAINT_REGEXP    67
7048#define SQLITE_INDEX_CONSTRAINT_NE        68
7049#define SQLITE_INDEX_CONSTRAINT_ISNOT     69
7050#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70
7051#define SQLITE_INDEX_CONSTRAINT_ISNULL    71
7052#define SQLITE_INDEX_CONSTRAINT_IS        72
7053#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150
7054
7055/*
7056** CAPI3REF: Register A Virtual Table Implementation
7057** METHOD: sqlite3
7058**
7059** ^These routines are used to register a new [virtual table module] name.
7060** ^Module names must be registered before
7061** creating a new [virtual table] using the module and before using a
7062** preexisting [virtual table] for the module.
7063**
7064** ^The module name is registered on the [database connection] specified
7065** by the first parameter.  ^The name of the module is given by the
7066** second parameter.  ^The third parameter is a pointer to
7067** the implementation of the [virtual table module].   ^The fourth
7068** parameter is an arbitrary client data pointer that is passed through
7069** into the [xCreate] and [xConnect] methods of the virtual table module
7070** when a new virtual table is be being created or reinitialized.
7071**
7072** ^The sqlite3_create_module_v2() interface has a fifth parameter which
7073** is a pointer to a destructor for the pClientData.  ^SQLite will
7074** invoke the destructor function (if it is not NULL) when SQLite
7075** no longer needs the pClientData pointer.  ^The destructor will also
7076** be invoked if the call to sqlite3_create_module_v2() fails.
7077** ^The sqlite3_create_module()
7078** interface is equivalent to sqlite3_create_module_v2() with a NULL
7079** destructor.
7080**
7081** ^If the third parameter (the pointer to the sqlite3_module object) is
7082** NULL then no new module is create and any existing modules with the
7083** same name are dropped.
7084**
7085** See also: [sqlite3_drop_modules()]
7086*/
7087int sqlite3_create_module(
7088  sqlite3 *db,               /* SQLite connection to register module with */
7089  const char *zName,         /* Name of the module */
7090  const sqlite3_module *p,   /* Methods for the module */
7091  void *pClientData          /* Client data for xCreate/xConnect */
7092);
7093int sqlite3_create_module_v2(
7094  sqlite3 *db,               /* SQLite connection to register module with */
7095  const char *zName,         /* Name of the module */
7096  const sqlite3_module *p,   /* Methods for the module */
7097  void *pClientData,         /* Client data for xCreate/xConnect */
7098  void(*xDestroy)(void*)     /* Module destructor function */
7099);
7100
7101/*
7102** CAPI3REF: Remove Unnecessary Virtual Table Implementations
7103** METHOD: sqlite3
7104**
7105** ^The sqlite3_drop_modules(D,L) interface removes all virtual
7106** table modules from database connection D except those named on list L.
7107** The L parameter must be either NULL or a pointer to an array of pointers
7108** to strings where the array is terminated by a single NULL pointer.
7109** ^If the L parameter is NULL, then all virtual table modules are removed.
7110**
7111** See also: [sqlite3_create_module()]
7112*/
7113int sqlite3_drop_modules(
7114  sqlite3 *db,                /* Remove modules from this connection */
7115  const char **azKeep         /* Except, do not remove the ones named here */
7116);
7117
7118/*
7119** CAPI3REF: Virtual Table Instance Object
7120** KEYWORDS: sqlite3_vtab
7121**
7122** Every [virtual table module] implementation uses a subclass
7123** of this object to describe a particular instance
7124** of the [virtual table].  Each subclass will
7125** be tailored to the specific needs of the module implementation.
7126** The purpose of this superclass is to define certain fields that are
7127** common to all module implementations.
7128**
7129** ^Virtual tables methods can set an error message by assigning a
7130** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
7131** take care that any prior string is freed by a call to [sqlite3_free()]
7132** prior to assigning a new string to zErrMsg.  ^After the error message
7133** is delivered up to the client application, the string will be automatically
7134** freed by sqlite3_free() and the zErrMsg field will be zeroed.
7135*/
7136struct sqlite3_vtab {
7137  const sqlite3_module *pModule;  /* The module for this virtual table */
7138  int nRef;                       /* Number of open cursors */
7139  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
7140  /* Virtual table implementations will typically add additional fields */
7141};
7142
7143/*
7144** CAPI3REF: Virtual Table Cursor Object
7145** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
7146**
7147** Every [virtual table module] implementation uses a subclass of the
7148** following structure to describe cursors that point into the
7149** [virtual table] and are used
7150** to loop through the virtual table.  Cursors are created using the
7151** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
7152** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
7153** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
7154** of the module.  Each module implementation will define
7155** the content of a cursor structure to suit its own needs.
7156**
7157** This superclass exists in order to define fields of the cursor that
7158** are common to all implementations.
7159*/
7160struct sqlite3_vtab_cursor {
7161  sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
7162  /* Virtual table implementations will typically add additional fields */
7163};
7164
7165/*
7166** CAPI3REF: Declare The Schema Of A Virtual Table
7167**
7168** ^The [xCreate] and [xConnect] methods of a
7169** [virtual table module] call this interface
7170** to declare the format (the names and datatypes of the columns) of
7171** the virtual tables they implement.
7172*/
7173int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
7174
7175/*
7176** CAPI3REF: Overload A Function For A Virtual Table
7177** METHOD: sqlite3
7178**
7179** ^(Virtual tables can provide alternative implementations of functions
7180** using the [xFindFunction] method of the [virtual table module].
7181** But global versions of those functions
7182** must exist in order to be overloaded.)^
7183**
7184** ^(This API makes sure a global version of a function with a particular
7185** name and number of parameters exists.  If no such function exists
7186** before this API is called, a new function is created.)^  ^The implementation
7187** of the new function always causes an exception to be thrown.  So
7188** the new function is not good for anything by itself.  Its only
7189** purpose is to be a placeholder function that can be overloaded
7190** by a [virtual table].
7191*/
7192int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
7193
7194/*
7195** The interface to the virtual-table mechanism defined above (back up
7196** to a comment remarkably similar to this one) is currently considered
7197** to be experimental.  The interface might change in incompatible ways.
7198** If this is a problem for you, do not use the interface at this time.
7199**
7200** When the virtual-table mechanism stabilizes, we will declare the
7201** interface fixed, support it indefinitely, and remove this comment.
7202*/
7203
7204/*
7205** CAPI3REF: A Handle To An Open BLOB
7206** KEYWORDS: {BLOB handle} {BLOB handles}
7207**
7208** An instance of this object represents an open BLOB on which
7209** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
7210** ^Objects of this type are created by [sqlite3_blob_open()]
7211** and destroyed by [sqlite3_blob_close()].
7212** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
7213** can be used to read or write small subsections of the BLOB.
7214** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
7215*/
7216typedef struct sqlite3_blob sqlite3_blob;
7217
7218/*
7219** CAPI3REF: Open A BLOB For Incremental I/O
7220** METHOD: sqlite3
7221** CONSTRUCTOR: sqlite3_blob
7222**
7223** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
7224** in row iRow, column zColumn, table zTable in database zDb;
7225** in other words, the same BLOB that would be selected by:
7226**
7227** <pre>
7228**     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
7229** </pre>)^
7230**
7231** ^(Parameter zDb is not the filename that contains the database, but
7232** rather the symbolic name of the database. For attached databases, this is
7233** the name that appears after the AS keyword in the [ATTACH] statement.
7234** For the main database file, the database name is "main". For TEMP
7235** tables, the database name is "temp".)^
7236**
7237** ^If the flags parameter is non-zero, then the BLOB is opened for read
7238** and write access. ^If the flags parameter is zero, the BLOB is opened for
7239** read-only access.
7240**
7241** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
7242** in *ppBlob. Otherwise an [error code] is returned and, unless the error
7243** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
7244** the API is not misused, it is always safe to call [sqlite3_blob_close()]
7245** on *ppBlob after this function it returns.
7246**
7247** This function fails with SQLITE_ERROR if any of the following are true:
7248** <ul>
7249**   <li> ^(Database zDb does not exist)^,
7250**   <li> ^(Table zTable does not exist within database zDb)^,
7251**   <li> ^(Table zTable is a WITHOUT ROWID table)^,
7252**   <li> ^(Column zColumn does not exist)^,
7253**   <li> ^(Row iRow is not present in the table)^,
7254**   <li> ^(The specified column of row iRow contains a value that is not
7255**         a TEXT or BLOB value)^,
7256**   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
7257**         constraint and the blob is being opened for read/write access)^,
7258**   <li> ^([foreign key constraints | Foreign key constraints] are enabled,
7259**         column zColumn is part of a [child key] definition and the blob is
7260**         being opened for read/write access)^.
7261** </ul>
7262**
7263** ^Unless it returns SQLITE_MISUSE, this function sets the
7264** [database connection] error code and message accessible via
7265** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
7266**
7267** A BLOB referenced by sqlite3_blob_open() may be read using the
7268** [sqlite3_blob_read()] interface and modified by using
7269** [sqlite3_blob_write()].  The [BLOB handle] can be moved to a
7270** different row of the same table using the [sqlite3_blob_reopen()]
7271** interface.  However, the column, table, or database of a [BLOB handle]
7272** cannot be changed after the [BLOB handle] is opened.
7273**
7274** ^(If the row that a BLOB handle points to is modified by an
7275** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
7276** then the BLOB handle is marked as "expired".
7277** This is true if any column of the row is changed, even a column
7278** other than the one the BLOB handle is open on.)^
7279** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
7280** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
7281** ^(Changes written into a BLOB prior to the BLOB expiring are not
7282** rolled back by the expiration of the BLOB.  Such changes will eventually
7283** commit if the transaction continues to completion.)^
7284**
7285** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
7286** the opened blob.  ^The size of a blob may not be changed by this
7287** interface.  Use the [UPDATE] SQL command to change the size of a
7288** blob.
7289**
7290** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
7291** and the built-in [zeroblob] SQL function may be used to create a
7292** zero-filled blob to read or write using the incremental-blob interface.
7293**
7294** To avoid a resource leak, every open [BLOB handle] should eventually
7295** be released by a call to [sqlite3_blob_close()].
7296**
7297** See also: [sqlite3_blob_close()],
7298** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
7299** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
7300*/
7301int sqlite3_blob_open(
7302  sqlite3*,
7303  const char *zDb,
7304  const char *zTable,
7305  const char *zColumn,
7306  sqlite3_int64 iRow,
7307  int flags,
7308  sqlite3_blob **ppBlob
7309);
7310
7311/*
7312** CAPI3REF: Move a BLOB Handle to a New Row
7313** METHOD: sqlite3_blob
7314**
7315** ^This function is used to move an existing [BLOB handle] so that it points
7316** to a different row of the same database table. ^The new row is identified
7317** by the rowid value passed as the second argument. Only the row can be
7318** changed. ^The database, table and column on which the blob handle is open
7319** remain the same. Moving an existing [BLOB handle] to a new row is
7320** faster than closing the existing handle and opening a new one.
7321**
7322** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
7323** it must exist and there must be either a blob or text value stored in
7324** the nominated column.)^ ^If the new row is not present in the table, or if
7325** it does not contain a blob or text value, or if another error occurs, an
7326** SQLite error code is returned and the blob handle is considered aborted.
7327** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
7328** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
7329** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
7330** always returns zero.
7331**
7332** ^This function sets the database handle error code and message.
7333*/
7334int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
7335
7336/*
7337** CAPI3REF: Close A BLOB Handle
7338** DESTRUCTOR: sqlite3_blob
7339**
7340** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
7341** unconditionally.  Even if this routine returns an error code, the
7342** handle is still closed.)^
7343**
7344** ^If the blob handle being closed was opened for read-write access, and if
7345** the database is in auto-commit mode and there are no other open read-write
7346** blob handles or active write statements, the current transaction is
7347** committed. ^If an error occurs while committing the transaction, an error
7348** code is returned and the transaction rolled back.
7349**
7350** Calling this function with an argument that is not a NULL pointer or an
7351** open blob handle results in undefined behaviour. ^Calling this routine
7352** with a null pointer (such as would be returned by a failed call to
7353** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
7354** is passed a valid open blob handle, the values returned by the
7355** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
7356*/
7357int sqlite3_blob_close(sqlite3_blob *);
7358
7359/*
7360** CAPI3REF: Return The Size Of An Open BLOB
7361** METHOD: sqlite3_blob
7362**
7363** ^Returns the size in bytes of the BLOB accessible via the
7364** successfully opened [BLOB handle] in its only argument.  ^The
7365** incremental blob I/O routines can only read or overwriting existing
7366** blob content; they cannot change the size of a blob.
7367**
7368** This routine only works on a [BLOB handle] which has been created
7369** by a prior successful call to [sqlite3_blob_open()] and which has not
7370** been closed by [sqlite3_blob_close()].  Passing any other pointer in
7371** to this routine results in undefined and probably undesirable behavior.
7372*/
7373int sqlite3_blob_bytes(sqlite3_blob *);
7374
7375/*
7376** CAPI3REF: Read Data From A BLOB Incrementally
7377** METHOD: sqlite3_blob
7378**
7379** ^(This function is used to read data from an open [BLOB handle] into a
7380** caller-supplied buffer. N bytes of data are copied into buffer Z
7381** from the open BLOB, starting at offset iOffset.)^
7382**
7383** ^If offset iOffset is less than N bytes from the end of the BLOB,
7384** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
7385** less than zero, [SQLITE_ERROR] is returned and no data is read.
7386** ^The size of the blob (and hence the maximum value of N+iOffset)
7387** can be determined using the [sqlite3_blob_bytes()] interface.
7388**
7389** ^An attempt to read from an expired [BLOB handle] fails with an
7390** error code of [SQLITE_ABORT].
7391**
7392** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
7393** Otherwise, an [error code] or an [extended error code] is returned.)^
7394**
7395** This routine only works on a [BLOB handle] which has been created
7396** by a prior successful call to [sqlite3_blob_open()] and which has not
7397** been closed by [sqlite3_blob_close()].  Passing any other pointer in
7398** to this routine results in undefined and probably undesirable behavior.
7399**
7400** See also: [sqlite3_blob_write()].
7401*/
7402int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
7403
7404/*
7405** CAPI3REF: Write Data Into A BLOB Incrementally
7406** METHOD: sqlite3_blob
7407**
7408** ^(This function is used to write data into an open [BLOB handle] from a
7409** caller-supplied buffer. N bytes of data are copied from the buffer Z
7410** into the open BLOB, starting at offset iOffset.)^
7411**
7412** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
7413** Otherwise, an  [error code] or an [extended error code] is returned.)^
7414** ^Unless SQLITE_MISUSE is returned, this function sets the
7415** [database connection] error code and message accessible via
7416** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
7417**
7418** ^If the [BLOB handle] passed as the first argument was not opened for
7419** writing (the flags parameter to [sqlite3_blob_open()] was zero),
7420** this function returns [SQLITE_READONLY].
7421**
7422** This function may only modify the contents of the BLOB; it is
7423** not possible to increase the size of a BLOB using this API.
7424** ^If offset iOffset is less than N bytes from the end of the BLOB,
7425** [SQLITE_ERROR] is returned and no data is written. The size of the
7426** BLOB (and hence the maximum value of N+iOffset) can be determined
7427** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
7428** than zero [SQLITE_ERROR] is returned and no data is written.
7429**
7430** ^An attempt to write to an expired [BLOB handle] fails with an
7431** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
7432** before the [BLOB handle] expired are not rolled back by the
7433** expiration of the handle, though of course those changes might
7434** have been overwritten by the statement that expired the BLOB handle
7435** or by other independent statements.
7436**
7437** This routine only works on a [BLOB handle] which has been created
7438** by a prior successful call to [sqlite3_blob_open()] and which has not
7439** been closed by [sqlite3_blob_close()].  Passing any other pointer in
7440** to this routine results in undefined and probably undesirable behavior.
7441**
7442** See also: [sqlite3_blob_read()].
7443*/
7444int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
7445
7446/*
7447** CAPI3REF: Virtual File System Objects
7448**
7449** A virtual filesystem (VFS) is an [sqlite3_vfs] object
7450** that SQLite uses to interact
7451** with the underlying operating system.  Most SQLite builds come with a
7452** single default VFS that is appropriate for the host computer.
7453** New VFSes can be registered and existing VFSes can be unregistered.
7454** The following interfaces are provided.
7455**
7456** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
7457** ^Names are case sensitive.
7458** ^Names are zero-terminated UTF-8 strings.
7459** ^If there is no match, a NULL pointer is returned.
7460** ^If zVfsName is NULL then the default VFS is returned.
7461**
7462** ^New VFSes are registered with sqlite3_vfs_register().
7463** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
7464** ^The same VFS can be registered multiple times without injury.
7465** ^To make an existing VFS into the default VFS, register it again
7466** with the makeDflt flag set.  If two different VFSes with the
7467** same name are registered, the behavior is undefined.  If a
7468** VFS is registered with a name that is NULL or an empty string,
7469** then the behavior is undefined.
7470**
7471** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
7472** ^(If the default VFS is unregistered, another VFS is chosen as
7473** the default.  The choice for the new VFS is arbitrary.)^
7474*/
7475sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
7476int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
7477int sqlite3_vfs_unregister(sqlite3_vfs*);
7478
7479/*
7480** CAPI3REF: Mutexes
7481**
7482** The SQLite core uses these routines for thread
7483** synchronization. Though they are intended for internal
7484** use by SQLite, code that links against SQLite is
7485** permitted to use any of these routines.
7486**
7487** The SQLite source code contains multiple implementations
7488** of these mutex routines.  An appropriate implementation
7489** is selected automatically at compile-time.  The following
7490** implementations are available in the SQLite core:
7491**
7492** <ul>
7493** <li>   SQLITE_MUTEX_PTHREADS
7494** <li>   SQLITE_MUTEX_W32
7495** <li>   SQLITE_MUTEX_NOOP
7496** </ul>
7497**
7498** The SQLITE_MUTEX_NOOP implementation is a set of routines
7499** that does no real locking and is appropriate for use in
7500** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
7501** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
7502** and Windows.
7503**
7504** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
7505** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
7506** implementation is included with the library. In this case the
7507** application must supply a custom mutex implementation using the
7508** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
7509** before calling sqlite3_initialize() or any other public sqlite3_
7510** function that calls sqlite3_initialize().
7511**
7512** ^The sqlite3_mutex_alloc() routine allocates a new
7513** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
7514** routine returns NULL if it is unable to allocate the requested
7515** mutex.  The argument to sqlite3_mutex_alloc() must one of these
7516** integer constants:
7517**
7518** <ul>
7519** <li>  SQLITE_MUTEX_FAST
7520** <li>  SQLITE_MUTEX_RECURSIVE
7521** <li>  SQLITE_MUTEX_STATIC_MAIN
7522** <li>  SQLITE_MUTEX_STATIC_MEM
7523** <li>  SQLITE_MUTEX_STATIC_OPEN
7524** <li>  SQLITE_MUTEX_STATIC_PRNG
7525** <li>  SQLITE_MUTEX_STATIC_LRU
7526** <li>  SQLITE_MUTEX_STATIC_PMEM
7527** <li>  SQLITE_MUTEX_STATIC_APP1
7528** <li>  SQLITE_MUTEX_STATIC_APP2
7529** <li>  SQLITE_MUTEX_STATIC_APP3
7530** <li>  SQLITE_MUTEX_STATIC_VFS1
7531** <li>  SQLITE_MUTEX_STATIC_VFS2
7532** <li>  SQLITE_MUTEX_STATIC_VFS3
7533** </ul>
7534**
7535** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
7536** cause sqlite3_mutex_alloc() to create
7537** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
7538** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
7539** The mutex implementation does not need to make a distinction
7540** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
7541** not want to.  SQLite will only request a recursive mutex in
7542** cases where it really needs one.  If a faster non-recursive mutex
7543** implementation is available on the host platform, the mutex subsystem
7544** might return such a mutex in response to SQLITE_MUTEX_FAST.
7545**
7546** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
7547** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
7548** a pointer to a static preexisting mutex.  ^Nine static mutexes are
7549** used by the current version of SQLite.  Future versions of SQLite
7550** may add additional static mutexes.  Static mutexes are for internal
7551** use by SQLite only.  Applications that use SQLite mutexes should
7552** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
7553** SQLITE_MUTEX_RECURSIVE.
7554**
7555** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
7556** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
7557** returns a different mutex on every call.  ^For the static
7558** mutex types, the same mutex is returned on every call that has
7559** the same type number.
7560**
7561** ^The sqlite3_mutex_free() routine deallocates a previously
7562** allocated dynamic mutex.  Attempting to deallocate a static
7563** mutex results in undefined behavior.
7564**
7565** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
7566** to enter a mutex.  ^If another thread is already within the mutex,
7567** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
7568** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
7569** upon successful entry.  ^(Mutexes created using
7570** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
7571** In such cases, the
7572** mutex must be exited an equal number of times before another thread
7573** can enter.)^  If the same thread tries to enter any mutex other
7574** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
7575**
7576** ^(Some systems (for example, Windows 95) do not support the operation
7577** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
7578** will always return SQLITE_BUSY. The SQLite core only ever uses
7579** sqlite3_mutex_try() as an optimization so this is acceptable
7580** behavior.)^
7581**
7582** ^The sqlite3_mutex_leave() routine exits a mutex that was
7583** previously entered by the same thread.   The behavior
7584** is undefined if the mutex is not currently entered by the
7585** calling thread or is not currently allocated.
7586**
7587** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
7588** sqlite3_mutex_leave() is a NULL pointer, then all three routines
7589** behave as no-ops.
7590**
7591** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
7592*/
7593sqlite3_mutex *sqlite3_mutex_alloc(int);
7594void sqlite3_mutex_free(sqlite3_mutex*);
7595void sqlite3_mutex_enter(sqlite3_mutex*);
7596int sqlite3_mutex_try(sqlite3_mutex*);
7597void sqlite3_mutex_leave(sqlite3_mutex*);
7598
7599/*
7600** CAPI3REF: Mutex Methods Object
7601**
7602** An instance of this structure defines the low-level routines
7603** used to allocate and use mutexes.
7604**
7605** Usually, the default mutex implementations provided by SQLite are
7606** sufficient, however the application has the option of substituting a custom
7607** implementation for specialized deployments or systems for which SQLite
7608** does not provide a suitable implementation. In this case, the application
7609** creates and populates an instance of this structure to pass
7610** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
7611** Additionally, an instance of this structure can be used as an
7612** output variable when querying the system for the current mutex
7613** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
7614**
7615** ^The xMutexInit method defined by this structure is invoked as
7616** part of system initialization by the sqlite3_initialize() function.
7617** ^The xMutexInit routine is called by SQLite exactly once for each
7618** effective call to [sqlite3_initialize()].
7619**
7620** ^The xMutexEnd method defined by this structure is invoked as
7621** part of system shutdown by the sqlite3_shutdown() function. The
7622** implementation of this method is expected to release all outstanding
7623** resources obtained by the mutex methods implementation, especially
7624** those obtained by the xMutexInit method.  ^The xMutexEnd()
7625** interface is invoked exactly once for each call to [sqlite3_shutdown()].
7626**
7627** ^(The remaining seven methods defined by this structure (xMutexAlloc,
7628** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
7629** xMutexNotheld) implement the following interfaces (respectively):
7630**
7631** <ul>
7632**   <li>  [sqlite3_mutex_alloc()] </li>
7633**   <li>  [sqlite3_mutex_free()] </li>
7634**   <li>  [sqlite3_mutex_enter()] </li>
7635**   <li>  [sqlite3_mutex_try()] </li>
7636**   <li>  [sqlite3_mutex_leave()] </li>
7637**   <li>  [sqlite3_mutex_held()] </li>
7638**   <li>  [sqlite3_mutex_notheld()] </li>
7639** </ul>)^
7640**
7641** The only difference is that the public sqlite3_XXX functions enumerated
7642** above silently ignore any invocations that pass a NULL pointer instead
7643** of a valid mutex handle. The implementations of the methods defined
7644** by this structure are not required to handle this case. The results
7645** of passing a NULL pointer instead of a valid mutex handle are undefined
7646** (i.e. it is acceptable to provide an implementation that segfaults if
7647** it is passed a NULL pointer).
7648**
7649** The xMutexInit() method must be threadsafe.  It must be harmless to
7650** invoke xMutexInit() multiple times within the same process and without
7651** intervening calls to xMutexEnd().  Second and subsequent calls to
7652** xMutexInit() must be no-ops.
7653**
7654** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
7655** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
7656** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
7657** memory allocation for a fast or recursive mutex.
7658**
7659** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
7660** called, but only if the prior call to xMutexInit returned SQLITE_OK.
7661** If xMutexInit fails in any way, it is expected to clean up after itself
7662** prior to returning.
7663*/
7664typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
7665struct sqlite3_mutex_methods {
7666  int (*xMutexInit)(void);
7667  int (*xMutexEnd)(void);
7668  sqlite3_mutex *(*xMutexAlloc)(int);
7669  void (*xMutexFree)(sqlite3_mutex *);
7670  void (*xMutexEnter)(sqlite3_mutex *);
7671  int (*xMutexTry)(sqlite3_mutex *);
7672  void (*xMutexLeave)(sqlite3_mutex *);
7673  int (*xMutexHeld)(sqlite3_mutex *);
7674  int (*xMutexNotheld)(sqlite3_mutex *);
7675};
7676
7677/*
7678** CAPI3REF: Mutex Verification Routines
7679**
7680** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
7681** are intended for use inside assert() statements.  The SQLite core
7682** never uses these routines except inside an assert() and applications
7683** are advised to follow the lead of the core.  The SQLite core only
7684** provides implementations for these routines when it is compiled
7685** with the SQLITE_DEBUG flag.  External mutex implementations
7686** are only required to provide these routines if SQLITE_DEBUG is
7687** defined and if NDEBUG is not defined.
7688**
7689** These routines should return true if the mutex in their argument
7690** is held or not held, respectively, by the calling thread.
7691**
7692** The implementation is not required to provide versions of these
7693** routines that actually work. If the implementation does not provide working
7694** versions of these routines, it should at least provide stubs that always
7695** return true so that one does not get spurious assertion failures.
7696**
7697** If the argument to sqlite3_mutex_held() is a NULL pointer then
7698** the routine should return 1.   This seems counter-intuitive since
7699** clearly the mutex cannot be held if it does not exist.  But
7700** the reason the mutex does not exist is because the build is not
7701** using mutexes.  And we do not want the assert() containing the
7702** call to sqlite3_mutex_held() to fail, so a non-zero return is
7703** the appropriate thing to do.  The sqlite3_mutex_notheld()
7704** interface should also return 1 when given a NULL pointer.
7705*/
7706#ifndef NDEBUG
7707int sqlite3_mutex_held(sqlite3_mutex*);
7708int sqlite3_mutex_notheld(sqlite3_mutex*);
7709#endif
7710
7711/*
7712** CAPI3REF: Mutex Types
7713**
7714** The [sqlite3_mutex_alloc()] interface takes a single argument
7715** which is one of these integer constants.
7716**
7717** The set of static mutexes may change from one SQLite release to the
7718** next.  Applications that override the built-in mutex logic must be
7719** prepared to accommodate additional static mutexes.
7720*/
7721#define SQLITE_MUTEX_FAST             0
7722#define SQLITE_MUTEX_RECURSIVE        1
7723#define SQLITE_MUTEX_STATIC_MAIN      2
7724#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
7725#define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
7726#define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
7727#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_randomness() */
7728#define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
7729#define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
7730#define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
7731#define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
7732#define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
7733#define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
7734#define SQLITE_MUTEX_STATIC_VFS1     11  /* For use by built-in VFS */
7735#define SQLITE_MUTEX_STATIC_VFS2     12  /* For use by extension VFS */
7736#define SQLITE_MUTEX_STATIC_VFS3     13  /* For use by application VFS */
7737
7738/* Legacy compatibility: */
7739#define SQLITE_MUTEX_STATIC_MASTER    2
7740
7741
7742/*
7743** CAPI3REF: Retrieve the mutex for a database connection
7744** METHOD: sqlite3
7745**
7746** ^This interface returns a pointer the [sqlite3_mutex] object that
7747** serializes access to the [database connection] given in the argument
7748** when the [threading mode] is Serialized.
7749** ^If the [threading mode] is Single-thread or Multi-thread then this
7750** routine returns a NULL pointer.
7751*/
7752sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
7753
7754/*
7755** CAPI3REF: Low-Level Control Of Database Files
7756** METHOD: sqlite3
7757** KEYWORDS: {file control}
7758**
7759** ^The [sqlite3_file_control()] interface makes a direct call to the
7760** xFileControl method for the [sqlite3_io_methods] object associated
7761** with a particular database identified by the second argument. ^The
7762** name of the database is "main" for the main database or "temp" for the
7763** TEMP database, or the name that appears after the AS keyword for
7764** databases that are added using the [ATTACH] SQL command.
7765** ^A NULL pointer can be used in place of "main" to refer to the
7766** main database file.
7767** ^The third and fourth parameters to this routine
7768** are passed directly through to the second and third parameters of
7769** the xFileControl method.  ^The return value of the xFileControl
7770** method becomes the return value of this routine.
7771**
7772** A few opcodes for [sqlite3_file_control()] are handled directly
7773** by the SQLite core and never invoke the
7774** sqlite3_io_methods.xFileControl method.
7775** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
7776** a pointer to the underlying [sqlite3_file] object to be written into
7777** the space pointed to by the 4th parameter.  The
7778** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns
7779** the [sqlite3_file] object associated with the journal file instead of
7780** the main database.  The [SQLITE_FCNTL_VFS_POINTER] opcode returns
7781** a pointer to the underlying [sqlite3_vfs] object for the file.
7782** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter
7783** from the pager.
7784**
7785** ^If the second parameter (zDbName) does not match the name of any
7786** open database file, then SQLITE_ERROR is returned.  ^This error
7787** code is not remembered and will not be recalled by [sqlite3_errcode()]
7788** or [sqlite3_errmsg()].  The underlying xFileControl method might
7789** also return SQLITE_ERROR.  There is no way to distinguish between
7790** an incorrect zDbName and an SQLITE_ERROR return from the underlying
7791** xFileControl method.
7792**
7793** See also: [file control opcodes]
7794*/
7795int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
7796
7797/*
7798** CAPI3REF: Testing Interface
7799**
7800** ^The sqlite3_test_control() interface is used to read out internal
7801** state of SQLite and to inject faults into SQLite for testing
7802** purposes.  ^The first parameter is an operation code that determines
7803** the number, meaning, and operation of all subsequent parameters.
7804**
7805** This interface is not for use by applications.  It exists solely
7806** for verifying the correct operation of the SQLite library.  Depending
7807** on how the SQLite library is compiled, this interface might not exist.
7808**
7809** The details of the operation codes, their meanings, the parameters
7810** they take, and what they do are all subject to change without notice.
7811** Unlike most of the SQLite API, this function is not guaranteed to
7812** operate consistently from one release to the next.
7813*/
7814int sqlite3_test_control(int op, ...);
7815
7816/*
7817** CAPI3REF: Testing Interface Operation Codes
7818**
7819** These constants are the valid operation code parameters used
7820** as the first argument to [sqlite3_test_control()].
7821**
7822** These parameters and their meanings are subject to change
7823** without notice.  These values are for testing purposes only.
7824** Applications should not use any of these parameters or the
7825** [sqlite3_test_control()] interface.
7826*/
7827#define SQLITE_TESTCTRL_FIRST                    5
7828#define SQLITE_TESTCTRL_PRNG_SAVE                5
7829#define SQLITE_TESTCTRL_PRNG_RESTORE             6
7830#define SQLITE_TESTCTRL_PRNG_RESET               7  /* NOT USED */
7831#define SQLITE_TESTCTRL_BITVEC_TEST              8
7832#define SQLITE_TESTCTRL_FAULT_INSTALL            9
7833#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
7834#define SQLITE_TESTCTRL_PENDING_BYTE            11
7835#define SQLITE_TESTCTRL_ASSERT                  12
7836#define SQLITE_TESTCTRL_ALWAYS                  13
7837#define SQLITE_TESTCTRL_RESERVE                 14  /* NOT USED */
7838#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
7839#define SQLITE_TESTCTRL_ISKEYWORD               16  /* NOT USED */
7840#define SQLITE_TESTCTRL_SCRATCHMALLOC           17  /* NOT USED */
7841#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS      17
7842#define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
7843#define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
7844#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD    19
7845#define SQLITE_TESTCTRL_NEVER_CORRUPT           20
7846#define SQLITE_TESTCTRL_VDBE_COVERAGE           21
7847#define SQLITE_TESTCTRL_BYTEORDER               22
7848#define SQLITE_TESTCTRL_ISINIT                  23
7849#define SQLITE_TESTCTRL_SORTER_MMAP             24
7850#define SQLITE_TESTCTRL_IMPOSTER                25
7851#define SQLITE_TESTCTRL_PARSER_COVERAGE         26
7852#define SQLITE_TESTCTRL_RESULT_INTREAL          27
7853#define SQLITE_TESTCTRL_PRNG_SEED               28
7854#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS     29
7855#define SQLITE_TESTCTRL_SEEK_COUNT              30
7856#define SQLITE_TESTCTRL_TRACEFLAGS              31
7857#define SQLITE_TESTCTRL_TUNE                    32
7858#define SQLITE_TESTCTRL_LAST                    32  /* Largest TESTCTRL */
7859
7860/*
7861** CAPI3REF: SQL Keyword Checking
7862**
7863** These routines provide access to the set of SQL language keywords
7864** recognized by SQLite.  Applications can uses these routines to determine
7865** whether or not a specific identifier needs to be escaped (for example,
7866** by enclosing in double-quotes) so as not to confuse the parser.
7867**
7868** The sqlite3_keyword_count() interface returns the number of distinct
7869** keywords understood by SQLite.
7870**
7871** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and
7872** makes *Z point to that keyword expressed as UTF8 and writes the number
7873** of bytes in the keyword into *L.  The string that *Z points to is not
7874** zero-terminated.  The sqlite3_keyword_name(N,Z,L) routine returns
7875** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
7876** or L are NULL or invalid pointers then calls to
7877** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
7878**
7879** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
7880** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
7881** if it is and zero if not.
7882**
7883** The parser used by SQLite is forgiving.  It is often possible to use
7884** a keyword as an identifier as long as such use does not result in a
7885** parsing ambiguity.  For example, the statement
7886** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
7887** creates a new table named "BEGIN" with three columns named
7888** "REPLACE", "PRAGMA", and "END".  Nevertheless, best practice is to avoid
7889** using keywords as identifiers.  Common techniques used to avoid keyword
7890** name collisions include:
7891** <ul>
7892** <li> Put all identifier names inside double-quotes.  This is the official
7893**      SQL way to escape identifier names.
7894** <li> Put identifier names inside &#91;...&#93;.  This is not standard SQL,
7895**      but it is what SQL Server does and so lots of programmers use this
7896**      technique.
7897** <li> Begin every identifier with the letter "Z" as no SQL keywords start
7898**      with "Z".
7899** <li> Include a digit somewhere in every identifier name.
7900** </ul>
7901**
7902** Note that the number of keywords understood by SQLite can depend on
7903** compile-time options.  For example, "VACUUM" is not a keyword if
7904** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option.  Also,
7905** new keywords may be added to future releases of SQLite.
7906*/
7907int sqlite3_keyword_count(void);
7908int sqlite3_keyword_name(int,const char**,int*);
7909int sqlite3_keyword_check(const char*,int);
7910
7911/*
7912** CAPI3REF: Dynamic String Object
7913** KEYWORDS: {dynamic string}
7914**
7915** An instance of the sqlite3_str object contains a dynamically-sized
7916** string under construction.
7917**
7918** The lifecycle of an sqlite3_str object is as follows:
7919** <ol>
7920** <li> ^The sqlite3_str object is created using [sqlite3_str_new()].
7921** <li> ^Text is appended to the sqlite3_str object using various
7922** methods, such as [sqlite3_str_appendf()].
7923** <li> ^The sqlite3_str object is destroyed and the string it created
7924** is returned using the [sqlite3_str_finish()] interface.
7925** </ol>
7926*/
7927typedef struct sqlite3_str sqlite3_str;
7928
7929/*
7930** CAPI3REF: Create A New Dynamic String Object
7931** CONSTRUCTOR: sqlite3_str
7932**
7933** ^The [sqlite3_str_new(D)] interface allocates and initializes
7934** a new [sqlite3_str] object.  To avoid memory leaks, the object returned by
7935** [sqlite3_str_new()] must be freed by a subsequent call to
7936** [sqlite3_str_finish(X)].
7937**
7938** ^The [sqlite3_str_new(D)] interface always returns a pointer to a
7939** valid [sqlite3_str] object, though in the event of an out-of-memory
7940** error the returned object might be a special singleton that will
7941** silently reject new text, always return SQLITE_NOMEM from
7942** [sqlite3_str_errcode()], always return 0 for
7943** [sqlite3_str_length()], and always return NULL from
7944** [sqlite3_str_finish(X)].  It is always safe to use the value
7945** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter
7946** to any of the other [sqlite3_str] methods.
7947**
7948** The D parameter to [sqlite3_str_new(D)] may be NULL.  If the
7949** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum
7950** length of the string contained in the [sqlite3_str] object will be
7951** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead
7952** of [SQLITE_MAX_LENGTH].
7953*/
7954sqlite3_str *sqlite3_str_new(sqlite3*);
7955
7956/*
7957** CAPI3REF: Finalize A Dynamic String
7958** DESTRUCTOR: sqlite3_str
7959**
7960** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
7961** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
7962** that contains the constructed string.  The calling application should
7963** pass the returned value to [sqlite3_free()] to avoid a memory leak.
7964** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
7965** errors were encountered during construction of the string.  ^The
7966** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the
7967** string in [sqlite3_str] object X is zero bytes long.
7968*/
7969char *sqlite3_str_finish(sqlite3_str*);
7970
7971/*
7972** CAPI3REF: Add Content To A Dynamic String
7973** METHOD: sqlite3_str
7974**
7975** These interfaces add content to an sqlite3_str object previously obtained
7976** from [sqlite3_str_new()].
7977**
7978** ^The [sqlite3_str_appendf(X,F,...)] and
7979** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
7980** functionality of SQLite to append formatted text onto the end of
7981** [sqlite3_str] object X.
7982**
7983** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
7984** onto the end of the [sqlite3_str] object X.  N must be non-negative.
7985** S must contain at least N non-zero bytes of content.  To append a
7986** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
7987** method instead.
7988**
7989** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of
7990** zero-terminated string S onto the end of [sqlite3_str] object X.
7991**
7992** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
7993** single-byte character C onto the end of [sqlite3_str] object X.
7994** ^This method can be used, for example, to add whitespace indentation.
7995**
7996** ^The [sqlite3_str_reset(X)] method resets the string under construction
7997** inside [sqlite3_str] object X back to zero bytes in length.
7998**
7999** These methods do not return a result code.  ^If an error occurs, that fact
8000** is recorded in the [sqlite3_str] object and can be recovered by a
8001** subsequent call to [sqlite3_str_errcode(X)].
8002*/
8003void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
8004void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
8005void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
8006void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
8007void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
8008void sqlite3_str_reset(sqlite3_str*);
8009
8010/*
8011** CAPI3REF: Status Of A Dynamic String
8012** METHOD: sqlite3_str
8013**
8014** These interfaces return the current status of an [sqlite3_str] object.
8015**
8016** ^If any prior errors have occurred while constructing the dynamic string
8017** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
8018** an appropriate error code.  ^The [sqlite3_str_errcode(X)] method returns
8019** [SQLITE_NOMEM] following any out-of-memory error, or
8020** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
8021** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
8022**
8023** ^The [sqlite3_str_length(X)] method returns the current length, in bytes,
8024** of the dynamic string under construction in [sqlite3_str] object X.
8025** ^The length returned by [sqlite3_str_length(X)] does not include the
8026** zero-termination byte.
8027**
8028** ^The [sqlite3_str_value(X)] method returns a pointer to the current
8029** content of the dynamic string under construction in X.  The value
8030** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
8031** and might be freed or altered by any subsequent method on the same
8032** [sqlite3_str] object.  Applications must not used the pointer returned
8033** [sqlite3_str_value(X)] after any subsequent method call on the same
8034** object.  ^Applications may change the content of the string returned
8035** by [sqlite3_str_value(X)] as long as they do not write into any bytes
8036** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
8037** write any byte after any subsequent sqlite3_str method call.
8038*/
8039int sqlite3_str_errcode(sqlite3_str*);
8040int sqlite3_str_length(sqlite3_str*);
8041char *sqlite3_str_value(sqlite3_str*);
8042
8043/*
8044** CAPI3REF: SQLite Runtime Status
8045**
8046** ^These interfaces are used to retrieve runtime status information
8047** about the performance of SQLite, and optionally to reset various
8048** highwater marks.  ^The first argument is an integer code for
8049** the specific parameter to measure.  ^(Recognized integer codes
8050** are of the form [status parameters | SQLITE_STATUS_...].)^
8051** ^The current value of the parameter is returned into *pCurrent.
8052** ^The highest recorded value is returned in *pHighwater.  ^If the
8053** resetFlag is true, then the highest record value is reset after
8054** *pHighwater is written.  ^(Some parameters do not record the highest
8055** value.  For those parameters
8056** nothing is written into *pHighwater and the resetFlag is ignored.)^
8057** ^(Other parameters record only the highwater mark and not the current
8058** value.  For these latter parameters nothing is written into *pCurrent.)^
8059**
8060** ^The sqlite3_status() and sqlite3_status64() routines return
8061** SQLITE_OK on success and a non-zero [error code] on failure.
8062**
8063** If either the current value or the highwater mark is too large to
8064** be represented by a 32-bit integer, then the values returned by
8065** sqlite3_status() are undefined.
8066**
8067** See also: [sqlite3_db_status()]
8068*/
8069int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
8070int sqlite3_status64(
8071  int op,
8072  sqlite3_int64 *pCurrent,
8073  sqlite3_int64 *pHighwater,
8074  int resetFlag
8075);
8076
8077
8078/*
8079** CAPI3REF: Status Parameters
8080** KEYWORDS: {status parameters}
8081**
8082** These integer constants designate various run-time status parameters
8083** that can be returned by [sqlite3_status()].
8084**
8085** <dl>
8086** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
8087** <dd>This parameter is the current amount of memory checked out
8088** using [sqlite3_malloc()], either directly or indirectly.  The
8089** figure includes calls made to [sqlite3_malloc()] by the application
8090** and internal memory usage by the SQLite library.  Auxiliary page-cache
8091** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
8092** this parameter.  The amount returned is the sum of the allocation
8093** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
8094**
8095** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
8096** <dd>This parameter records the largest memory allocation request
8097** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
8098** internal equivalents).  Only the value returned in the
8099** *pHighwater parameter to [sqlite3_status()] is of interest.
8100** The value written into the *pCurrent parameter is undefined.</dd>)^
8101**
8102** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
8103** <dd>This parameter records the number of separate memory allocations
8104** currently checked out.</dd>)^
8105**
8106** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
8107** <dd>This parameter returns the number of pages used out of the
8108** [pagecache memory allocator] that was configured using
8109** [SQLITE_CONFIG_PAGECACHE].  The
8110** value returned is in pages, not in bytes.</dd>)^
8111**
8112** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
8113** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
8114** <dd>This parameter returns the number of bytes of page cache
8115** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
8116** buffer and where forced to overflow to [sqlite3_malloc()].  The
8117** returned value includes allocations that overflowed because they
8118** where too large (they were larger than the "sz" parameter to
8119** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
8120** no space was left in the page cache.</dd>)^
8121**
8122** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
8123** <dd>This parameter records the largest memory allocation request
8124** handed to the [pagecache memory allocator].  Only the value returned in the
8125** *pHighwater parameter to [sqlite3_status()] is of interest.
8126** The value written into the *pCurrent parameter is undefined.</dd>)^
8127**
8128** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
8129** <dd>No longer used.</dd>
8130**
8131** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
8132** <dd>No longer used.</dd>
8133**
8134** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
8135** <dd>No longer used.</dd>
8136**
8137** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
8138** <dd>The *pHighwater parameter records the deepest parser stack.
8139** The *pCurrent value is undefined.  The *pHighwater value is only
8140** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
8141** </dl>
8142**
8143** New status parameters may be added from time to time.
8144*/
8145#define SQLITE_STATUS_MEMORY_USED          0
8146#define SQLITE_STATUS_PAGECACHE_USED       1
8147#define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
8148#define SQLITE_STATUS_SCRATCH_USED         3  /* NOT USED */
8149#define SQLITE_STATUS_SCRATCH_OVERFLOW     4  /* NOT USED */
8150#define SQLITE_STATUS_MALLOC_SIZE          5
8151#define SQLITE_STATUS_PARSER_STACK         6
8152#define SQLITE_STATUS_PAGECACHE_SIZE       7
8153#define SQLITE_STATUS_SCRATCH_SIZE         8  /* NOT USED */
8154#define SQLITE_STATUS_MALLOC_COUNT         9
8155
8156/*
8157** CAPI3REF: Database Connection Status
8158** METHOD: sqlite3
8159**
8160** ^This interface is used to retrieve runtime status information
8161** about a single [database connection].  ^The first argument is the
8162** database connection object to be interrogated.  ^The second argument
8163** is an integer constant, taken from the set of
8164** [SQLITE_DBSTATUS options], that
8165** determines the parameter to interrogate.  The set of
8166** [SQLITE_DBSTATUS options] is likely
8167** to grow in future releases of SQLite.
8168**
8169** ^The current value of the requested parameter is written into *pCur
8170** and the highest instantaneous value is written into *pHiwtr.  ^If
8171** the resetFlg is true, then the highest instantaneous value is
8172** reset back down to the current value.
8173**
8174** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
8175** non-zero [error code] on failure.
8176**
8177** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
8178*/
8179int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
8180
8181/*
8182** CAPI3REF: Status Parameters for database connections
8183** KEYWORDS: {SQLITE_DBSTATUS options}
8184**
8185** These constants are the available integer "verbs" that can be passed as
8186** the second argument to the [sqlite3_db_status()] interface.
8187**
8188** New verbs may be added in future releases of SQLite. Existing verbs
8189** might be discontinued. Applications should check the return code from
8190** [sqlite3_db_status()] to make sure that the call worked.
8191** The [sqlite3_db_status()] interface will return a non-zero error code
8192** if a discontinued or unsupported verb is invoked.
8193**
8194** <dl>
8195** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
8196** <dd>This parameter returns the number of lookaside memory slots currently
8197** checked out.</dd>)^
8198**
8199** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
8200** <dd>This parameter returns the number of malloc attempts that were
8201** satisfied using lookaside memory. Only the high-water value is meaningful;
8202** the current value is always zero.)^
8203**
8204** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
8205** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
8206** <dd>This parameter returns the number malloc attempts that might have
8207** been satisfied using lookaside memory but failed due to the amount of
8208** memory requested being larger than the lookaside slot size.
8209** Only the high-water value is meaningful;
8210** the current value is always zero.)^
8211**
8212** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
8213** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
8214** <dd>This parameter returns the number malloc attempts that might have
8215** been satisfied using lookaside memory but failed due to all lookaside
8216** memory already being in use.
8217** Only the high-water value is meaningful;
8218** the current value is always zero.)^
8219**
8220** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
8221** <dd>This parameter returns the approximate number of bytes of heap
8222** memory used by all pager caches associated with the database connection.)^
8223** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
8224**
8225** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
8226** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
8227** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
8228** pager cache is shared between two or more connections the bytes of heap
8229** memory used by that pager cache is divided evenly between the attached
8230** connections.)^  In other words, if none of the pager caches associated
8231** with the database connection are shared, this request returns the same
8232** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
8233** shared, the value returned by this call will be smaller than that returned
8234** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
8235** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
8236**
8237** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
8238** <dd>This parameter returns the approximate number of bytes of heap
8239** memory used to store the schema for all databases associated
8240** with the connection - main, temp, and any [ATTACH]-ed databases.)^
8241** ^The full amount of memory used by the schemas is reported, even if the
8242** schema memory is shared with other database connections due to
8243** [shared cache mode] being enabled.
8244** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
8245**
8246** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
8247** <dd>This parameter returns the approximate number of bytes of heap
8248** and lookaside memory used by all prepared statements associated with
8249** the database connection.)^
8250** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
8251** </dd>
8252**
8253** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
8254** <dd>This parameter returns the number of pager cache hits that have
8255** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
8256** is always 0.
8257** </dd>
8258**
8259** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
8260** <dd>This parameter returns the number of pager cache misses that have
8261** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
8262** is always 0.
8263** </dd>
8264**
8265** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
8266** <dd>This parameter returns the number of dirty cache entries that have
8267** been written to disk. Specifically, the number of pages written to the
8268** wal file in wal mode databases, or the number of pages written to the
8269** database file in rollback mode databases. Any pages written as part of
8270** transaction rollback or database recovery operations are not included.
8271** If an IO or other error occurs while writing a page to disk, the effect
8272** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
8273** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
8274** </dd>
8275**
8276** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
8277** <dd>This parameter returns the number of dirty cache entries that have
8278** been written to disk in the middle of a transaction due to the page
8279** cache overflowing. Transactions are more efficient if they are written
8280** to disk all at once. When pages spill mid-transaction, that introduces
8281** additional overhead. This parameter can be used help identify
8282** inefficiencies that can be resolved by increasing the cache size.
8283** </dd>
8284**
8285** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
8286** <dd>This parameter returns zero for the current value if and only if
8287** all foreign key constraints (deferred or immediate) have been
8288** resolved.)^  ^The highwater mark is always 0.
8289** </dd>
8290** </dl>
8291*/
8292#define SQLITE_DBSTATUS_LOOKASIDE_USED       0
8293#define SQLITE_DBSTATUS_CACHE_USED           1
8294#define SQLITE_DBSTATUS_SCHEMA_USED          2
8295#define SQLITE_DBSTATUS_STMT_USED            3
8296#define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
8297#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
8298#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
8299#define SQLITE_DBSTATUS_CACHE_HIT            7
8300#define SQLITE_DBSTATUS_CACHE_MISS           8
8301#define SQLITE_DBSTATUS_CACHE_WRITE          9
8302#define SQLITE_DBSTATUS_DEFERRED_FKS        10
8303#define SQLITE_DBSTATUS_CACHE_USED_SHARED   11
8304#define SQLITE_DBSTATUS_CACHE_SPILL         12
8305#define SQLITE_DBSTATUS_MAX                 12   /* Largest defined DBSTATUS */
8306
8307
8308/*
8309** CAPI3REF: Prepared Statement Status
8310** METHOD: sqlite3_stmt
8311**
8312** ^(Each prepared statement maintains various
8313** [SQLITE_STMTSTATUS counters] that measure the number
8314** of times it has performed specific operations.)^  These counters can
8315** be used to monitor the performance characteristics of the prepared
8316** statements.  For example, if the number of table steps greatly exceeds
8317** the number of table searches or result rows, that would tend to indicate
8318** that the prepared statement is using a full table scan rather than
8319** an index.
8320**
8321** ^(This interface is used to retrieve and reset counter values from
8322** a [prepared statement].  The first argument is the prepared statement
8323** object to be interrogated.  The second argument
8324** is an integer code for a specific [SQLITE_STMTSTATUS counter]
8325** to be interrogated.)^
8326** ^The current value of the requested counter is returned.
8327** ^If the resetFlg is true, then the counter is reset to zero after this
8328** interface call returns.
8329**
8330** See also: [sqlite3_status()] and [sqlite3_db_status()].
8331*/
8332int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
8333
8334/*
8335** CAPI3REF: Status Parameters for prepared statements
8336** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
8337**
8338** These preprocessor macros define integer codes that name counter
8339** values associated with the [sqlite3_stmt_status()] interface.
8340** The meanings of the various counters are as follows:
8341**
8342** <dl>
8343** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
8344** <dd>^This is the number of times that SQLite has stepped forward in
8345** a table as part of a full table scan.  Large numbers for this counter
8346** may indicate opportunities for performance improvement through
8347** careful use of indices.</dd>
8348**
8349** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
8350** <dd>^This is the number of sort operations that have occurred.
8351** A non-zero value in this counter may indicate an opportunity to
8352** improvement performance through careful use of indices.</dd>
8353**
8354** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
8355** <dd>^This is the number of rows inserted into transient indices that
8356** were created automatically in order to help joins run faster.
8357** A non-zero value in this counter may indicate an opportunity to
8358** improvement performance by adding permanent indices that do not
8359** need to be reinitialized each time the statement is run.</dd>
8360**
8361** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
8362** <dd>^This is the number of virtual machine operations executed
8363** by the prepared statement if that number is less than or equal
8364** to 2147483647.  The number of virtual machine operations can be
8365** used as a proxy for the total work done by the prepared statement.
8366** If the number of virtual machine operations exceeds 2147483647
8367** then the value returned by this statement status code is undefined.
8368**
8369** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
8370** <dd>^This is the number of times that the prepare statement has been
8371** automatically regenerated due to schema changes or changes to
8372** [bound parameters] that might affect the query plan.
8373**
8374** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
8375** <dd>^This is the number of times that the prepared statement has
8376** been run.  A single "run" for the purposes of this counter is one
8377** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
8378** The counter is incremented on the first [sqlite3_step()] call of each
8379** cycle.
8380**
8381** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
8382** <dd>^This is the approximate number of bytes of heap memory
8383** used to store the prepared statement.  ^This value is not actually
8384** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
8385** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
8386** </dd>
8387** </dl>
8388*/
8389#define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
8390#define SQLITE_STMTSTATUS_SORT              2
8391#define SQLITE_STMTSTATUS_AUTOINDEX         3
8392#define SQLITE_STMTSTATUS_VM_STEP           4
8393#define SQLITE_STMTSTATUS_REPREPARE         5
8394#define SQLITE_STMTSTATUS_RUN               6
8395#define SQLITE_STMTSTATUS_MEMUSED           99
8396
8397/*
8398** CAPI3REF: Custom Page Cache Object
8399**
8400** The sqlite3_pcache type is opaque.  It is implemented by
8401** the pluggable module.  The SQLite core has no knowledge of
8402** its size or internal structure and never deals with the
8403** sqlite3_pcache object except by holding and passing pointers
8404** to the object.
8405**
8406** See [sqlite3_pcache_methods2] for additional information.
8407*/
8408typedef struct sqlite3_pcache sqlite3_pcache;
8409
8410/*
8411** CAPI3REF: Custom Page Cache Object
8412**
8413** The sqlite3_pcache_page object represents a single page in the
8414** page cache.  The page cache will allocate instances of this
8415** object.  Various methods of the page cache use pointers to instances
8416** of this object as parameters or as their return value.
8417**
8418** See [sqlite3_pcache_methods2] for additional information.
8419*/
8420typedef struct sqlite3_pcache_page sqlite3_pcache_page;
8421struct sqlite3_pcache_page {
8422  void *pBuf;        /* The content of the page */
8423  void *pExtra;      /* Extra information associated with the page */
8424};
8425
8426/*
8427** CAPI3REF: Application Defined Page Cache.
8428** KEYWORDS: {page cache}
8429**
8430** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
8431** register an alternative page cache implementation by passing in an
8432** instance of the sqlite3_pcache_methods2 structure.)^
8433** In many applications, most of the heap memory allocated by
8434** SQLite is used for the page cache.
8435** By implementing a
8436** custom page cache using this API, an application can better control
8437** the amount of memory consumed by SQLite, the way in which
8438** that memory is allocated and released, and the policies used to
8439** determine exactly which parts of a database file are cached and for
8440** how long.
8441**
8442** The alternative page cache mechanism is an
8443** extreme measure that is only needed by the most demanding applications.
8444** The built-in page cache is recommended for most uses.
8445**
8446** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
8447** internal buffer by SQLite within the call to [sqlite3_config].  Hence
8448** the application may discard the parameter after the call to
8449** [sqlite3_config()] returns.)^
8450**
8451** [[the xInit() page cache method]]
8452** ^(The xInit() method is called once for each effective
8453** call to [sqlite3_initialize()])^
8454** (usually only once during the lifetime of the process). ^(The xInit()
8455** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
8456** The intent of the xInit() method is to set up global data structures
8457** required by the custom page cache implementation.
8458** ^(If the xInit() method is NULL, then the
8459** built-in default page cache is used instead of the application defined
8460** page cache.)^
8461**
8462** [[the xShutdown() page cache method]]
8463** ^The xShutdown() method is called by [sqlite3_shutdown()].
8464** It can be used to clean up
8465** any outstanding resources before process shutdown, if required.
8466** ^The xShutdown() method may be NULL.
8467**
8468** ^SQLite automatically serializes calls to the xInit method,
8469** so the xInit method need not be threadsafe.  ^The
8470** xShutdown method is only called from [sqlite3_shutdown()] so it does
8471** not need to be threadsafe either.  All other methods must be threadsafe
8472** in multithreaded applications.
8473**
8474** ^SQLite will never invoke xInit() more than once without an intervening
8475** call to xShutdown().
8476**
8477** [[the xCreate() page cache methods]]
8478** ^SQLite invokes the xCreate() method to construct a new cache instance.
8479** SQLite will typically create one cache instance for each open database file,
8480** though this is not guaranteed. ^The
8481** first parameter, szPage, is the size in bytes of the pages that must
8482** be allocated by the cache.  ^szPage will always a power of two.  ^The
8483** second parameter szExtra is a number of bytes of extra storage
8484** associated with each page cache entry.  ^The szExtra parameter will
8485** a number less than 250.  SQLite will use the
8486** extra szExtra bytes on each page to store metadata about the underlying
8487** database page on disk.  The value passed into szExtra depends
8488** on the SQLite version, the target platform, and how SQLite was compiled.
8489** ^The third argument to xCreate(), bPurgeable, is true if the cache being
8490** created will be used to cache database pages of a file stored on disk, or
8491** false if it is used for an in-memory database. The cache implementation
8492** does not have to do anything special based with the value of bPurgeable;
8493** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
8494** never invoke xUnpin() except to deliberately delete a page.
8495** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
8496** false will always have the "discard" flag set to true.
8497** ^Hence, a cache created with bPurgeable false will
8498** never contain any unpinned pages.
8499**
8500** [[the xCachesize() page cache method]]
8501** ^(The xCachesize() method may be called at any time by SQLite to set the
8502** suggested maximum cache-size (number of pages stored by) the cache
8503** instance passed as the first argument. This is the value configured using
8504** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
8505** parameter, the implementation is not required to do anything with this
8506** value; it is advisory only.
8507**
8508** [[the xPagecount() page cache methods]]
8509** The xPagecount() method must return the number of pages currently
8510** stored in the cache, both pinned and unpinned.
8511**
8512** [[the xFetch() page cache methods]]
8513** The xFetch() method locates a page in the cache and returns a pointer to
8514** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
8515** The pBuf element of the returned sqlite3_pcache_page object will be a
8516** pointer to a buffer of szPage bytes used to store the content of a
8517** single database page.  The pExtra element of sqlite3_pcache_page will be
8518** a pointer to the szExtra bytes of extra storage that SQLite has requested
8519** for each entry in the page cache.
8520**
8521** The page to be fetched is determined by the key. ^The minimum key value
8522** is 1.  After it has been retrieved using xFetch, the page is considered
8523** to be "pinned".
8524**
8525** If the requested page is already in the page cache, then the page cache
8526** implementation must return a pointer to the page buffer with its content
8527** intact.  If the requested page is not already in the cache, then the
8528** cache implementation should use the value of the createFlag
8529** parameter to help it determined what action to take:
8530**
8531** <table border=1 width=85% align=center>
8532** <tr><th> createFlag <th> Behavior when page is not already in cache
8533** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
8534** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
8535**                 Otherwise return NULL.
8536** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
8537**                 NULL if allocating a new page is effectively impossible.
8538** </table>
8539**
8540** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
8541** will only use a createFlag of 2 after a prior call with a createFlag of 1
8542** failed.)^  In between the xFetch() calls, SQLite may
8543** attempt to unpin one or more cache pages by spilling the content of
8544** pinned pages to disk and synching the operating system disk cache.
8545**
8546** [[the xUnpin() page cache method]]
8547** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
8548** as its second argument.  If the third parameter, discard, is non-zero,
8549** then the page must be evicted from the cache.
8550** ^If the discard parameter is
8551** zero, then the page may be discarded or retained at the discretion of
8552** page cache implementation. ^The page cache implementation
8553** may choose to evict unpinned pages at any time.
8554**
8555** The cache must not perform any reference counting. A single
8556** call to xUnpin() unpins the page regardless of the number of prior calls
8557** to xFetch().
8558**
8559** [[the xRekey() page cache methods]]
8560** The xRekey() method is used to change the key value associated with the
8561** page passed as the second argument. If the cache
8562** previously contains an entry associated with newKey, it must be
8563** discarded. ^Any prior cache entry associated with newKey is guaranteed not
8564** to be pinned.
8565**
8566** When SQLite calls the xTruncate() method, the cache must discard all
8567** existing cache entries with page numbers (keys) greater than or equal
8568** to the value of the iLimit parameter passed to xTruncate(). If any
8569** of these pages are pinned, they are implicitly unpinned, meaning that
8570** they can be safely discarded.
8571**
8572** [[the xDestroy() page cache method]]
8573** ^The xDestroy() method is used to delete a cache allocated by xCreate().
8574** All resources associated with the specified cache should be freed. ^After
8575** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
8576** handle invalid, and will not use it with any other sqlite3_pcache_methods2
8577** functions.
8578**
8579** [[the xShrink() page cache method]]
8580** ^SQLite invokes the xShrink() method when it wants the page cache to
8581** free up as much of heap memory as possible.  The page cache implementation
8582** is not obligated to free any memory, but well-behaved implementations should
8583** do their best.
8584*/
8585typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
8586struct sqlite3_pcache_methods2 {
8587  int iVersion;
8588  void *pArg;
8589  int (*xInit)(void*);
8590  void (*xShutdown)(void*);
8591  sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
8592  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
8593  int (*xPagecount)(sqlite3_pcache*);
8594  sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
8595  void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
8596  void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
8597      unsigned oldKey, unsigned newKey);
8598  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
8599  void (*xDestroy)(sqlite3_pcache*);
8600  void (*xShrink)(sqlite3_pcache*);
8601};
8602
8603/*
8604** This is the obsolete pcache_methods object that has now been replaced
8605** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
8606** retained in the header file for backwards compatibility only.
8607*/
8608typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
8609struct sqlite3_pcache_methods {
8610  void *pArg;
8611  int (*xInit)(void*);
8612  void (*xShutdown)(void*);
8613  sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
8614  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
8615  int (*xPagecount)(sqlite3_pcache*);
8616  void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
8617  void (*xUnpin)(sqlite3_pcache*, void*, int discard);
8618  void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
8619  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
8620  void (*xDestroy)(sqlite3_pcache*);
8621};
8622
8623
8624/*
8625** CAPI3REF: Online Backup Object
8626**
8627** The sqlite3_backup object records state information about an ongoing
8628** online backup operation.  ^The sqlite3_backup object is created by
8629** a call to [sqlite3_backup_init()] and is destroyed by a call to
8630** [sqlite3_backup_finish()].
8631**
8632** See Also: [Using the SQLite Online Backup API]
8633*/
8634typedef struct sqlite3_backup sqlite3_backup;
8635
8636/*
8637** CAPI3REF: Online Backup API.
8638**
8639** The backup API copies the content of one database into another.
8640** It is useful either for creating backups of databases or
8641** for copying in-memory databases to or from persistent files.
8642**
8643** See Also: [Using the SQLite Online Backup API]
8644**
8645** ^SQLite holds a write transaction open on the destination database file
8646** for the duration of the backup operation.
8647** ^The source database is read-locked only while it is being read;
8648** it is not locked continuously for the entire backup operation.
8649** ^Thus, the backup may be performed on a live source database without
8650** preventing other database connections from
8651** reading or writing to the source database while the backup is underway.
8652**
8653** ^(To perform a backup operation:
8654**   <ol>
8655**     <li><b>sqlite3_backup_init()</b> is called once to initialize the
8656**         backup,
8657**     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
8658**         the data between the two databases, and finally
8659**     <li><b>sqlite3_backup_finish()</b> is called to release all resources
8660**         associated with the backup operation.
8661**   </ol>)^
8662** There should be exactly one call to sqlite3_backup_finish() for each
8663** successful call to sqlite3_backup_init().
8664**
8665** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
8666**
8667** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
8668** [database connection] associated with the destination database
8669** and the database name, respectively.
8670** ^The database name is "main" for the main database, "temp" for the
8671** temporary database, or the name specified after the AS keyword in
8672** an [ATTACH] statement for an attached database.
8673** ^The S and M arguments passed to
8674** sqlite3_backup_init(D,N,S,M) identify the [database connection]
8675** and database name of the source database, respectively.
8676** ^The source and destination [database connections] (parameters S and D)
8677** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
8678** an error.
8679**
8680** ^A call to sqlite3_backup_init() will fail, returning NULL, if
8681** there is already a read or read-write transaction open on the
8682** destination database.
8683**
8684** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
8685** returned and an error code and error message are stored in the
8686** destination [database connection] D.
8687** ^The error code and message for the failed call to sqlite3_backup_init()
8688** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
8689** [sqlite3_errmsg16()] functions.
8690** ^A successful call to sqlite3_backup_init() returns a pointer to an
8691** [sqlite3_backup] object.
8692** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
8693** sqlite3_backup_finish() functions to perform the specified backup
8694** operation.
8695**
8696** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
8697**
8698** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
8699** the source and destination databases specified by [sqlite3_backup] object B.
8700** ^If N is negative, all remaining source pages are copied.
8701** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
8702** are still more pages to be copied, then the function returns [SQLITE_OK].
8703** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
8704** from source to destination, then it returns [SQLITE_DONE].
8705** ^If an error occurs while running sqlite3_backup_step(B,N),
8706** then an [error code] is returned. ^As well as [SQLITE_OK] and
8707** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
8708** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
8709** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
8710**
8711** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
8712** <ol>
8713** <li> the destination database was opened read-only, or
8714** <li> the destination database is using write-ahead-log journaling
8715** and the destination and source page sizes differ, or
8716** <li> the destination database is an in-memory database and the
8717** destination and source page sizes differ.
8718** </ol>)^
8719**
8720** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
8721** the [sqlite3_busy_handler | busy-handler function]
8722** is invoked (if one is specified). ^If the
8723** busy-handler returns non-zero before the lock is available, then
8724** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
8725** sqlite3_backup_step() can be retried later. ^If the source
8726** [database connection]
8727** is being used to write to the source database when sqlite3_backup_step()
8728** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
8729** case the call to sqlite3_backup_step() can be retried later on. ^(If
8730** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
8731** [SQLITE_READONLY] is returned, then
8732** there is no point in retrying the call to sqlite3_backup_step(). These
8733** errors are considered fatal.)^  The application must accept
8734** that the backup operation has failed and pass the backup operation handle
8735** to the sqlite3_backup_finish() to release associated resources.
8736**
8737** ^The first call to sqlite3_backup_step() obtains an exclusive lock
8738** on the destination file. ^The exclusive lock is not released until either
8739** sqlite3_backup_finish() is called or the backup operation is complete
8740** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
8741** sqlite3_backup_step() obtains a [shared lock] on the source database that
8742** lasts for the duration of the sqlite3_backup_step() call.
8743** ^Because the source database is not locked between calls to
8744** sqlite3_backup_step(), the source database may be modified mid-way
8745** through the backup process.  ^If the source database is modified by an
8746** external process or via a database connection other than the one being
8747** used by the backup operation, then the backup will be automatically
8748** restarted by the next call to sqlite3_backup_step(). ^If the source
8749** database is modified by the using the same database connection as is used
8750** by the backup operation, then the backup database is automatically
8751** updated at the same time.
8752**
8753** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
8754**
8755** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
8756** application wishes to abandon the backup operation, the application
8757** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
8758** ^The sqlite3_backup_finish() interfaces releases all
8759** resources associated with the [sqlite3_backup] object.
8760** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
8761** active write-transaction on the destination database is rolled back.
8762** The [sqlite3_backup] object is invalid
8763** and may not be used following a call to sqlite3_backup_finish().
8764**
8765** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
8766** sqlite3_backup_step() errors occurred, regardless or whether or not
8767** sqlite3_backup_step() completed.
8768** ^If an out-of-memory condition or IO error occurred during any prior
8769** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
8770** sqlite3_backup_finish() returns the corresponding [error code].
8771**
8772** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
8773** is not a permanent error and does not affect the return value of
8774** sqlite3_backup_finish().
8775**
8776** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
8777** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
8778**
8779** ^The sqlite3_backup_remaining() routine returns the number of pages still
8780** to be backed up at the conclusion of the most recent sqlite3_backup_step().
8781** ^The sqlite3_backup_pagecount() routine returns the total number of pages
8782** in the source database at the conclusion of the most recent
8783** sqlite3_backup_step().
8784** ^(The values returned by these functions are only updated by
8785** sqlite3_backup_step(). If the source database is modified in a way that
8786** changes the size of the source database or the number of pages remaining,
8787** those changes are not reflected in the output of sqlite3_backup_pagecount()
8788** and sqlite3_backup_remaining() until after the next
8789** sqlite3_backup_step().)^
8790**
8791** <b>Concurrent Usage of Database Handles</b>
8792**
8793** ^The source [database connection] may be used by the application for other
8794** purposes while a backup operation is underway or being initialized.
8795** ^If SQLite is compiled and configured to support threadsafe database
8796** connections, then the source database connection may be used concurrently
8797** from within other threads.
8798**
8799** However, the application must guarantee that the destination
8800** [database connection] is not passed to any other API (by any thread) after
8801** sqlite3_backup_init() is called and before the corresponding call to
8802** sqlite3_backup_finish().  SQLite does not currently check to see
8803** if the application incorrectly accesses the destination [database connection]
8804** and so no error code is reported, but the operations may malfunction
8805** nevertheless.  Use of the destination database connection while a
8806** backup is in progress might also also cause a mutex deadlock.
8807**
8808** If running in [shared cache mode], the application must
8809** guarantee that the shared cache used by the destination database
8810** is not accessed while the backup is running. In practice this means
8811** that the application must guarantee that the disk file being
8812** backed up to is not accessed by any connection within the process,
8813** not just the specific connection that was passed to sqlite3_backup_init().
8814**
8815** The [sqlite3_backup] object itself is partially threadsafe. Multiple
8816** threads may safely make multiple concurrent calls to sqlite3_backup_step().
8817** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
8818** APIs are not strictly speaking threadsafe. If they are invoked at the
8819** same time as another thread is invoking sqlite3_backup_step() it is
8820** possible that they return invalid values.
8821*/
8822sqlite3_backup *sqlite3_backup_init(
8823  sqlite3 *pDest,                        /* Destination database handle */
8824  const char *zDestName,                 /* Destination database name */
8825  sqlite3 *pSource,                      /* Source database handle */
8826  const char *zSourceName                /* Source database name */
8827);
8828int sqlite3_backup_step(sqlite3_backup *p, int nPage);
8829int sqlite3_backup_finish(sqlite3_backup *p);
8830int sqlite3_backup_remaining(sqlite3_backup *p);
8831int sqlite3_backup_pagecount(sqlite3_backup *p);
8832
8833/*
8834** CAPI3REF: Unlock Notification
8835** METHOD: sqlite3
8836**
8837** ^When running in shared-cache mode, a database operation may fail with
8838** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
8839** individual tables within the shared-cache cannot be obtained. See
8840** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
8841** ^This API may be used to register a callback that SQLite will invoke
8842** when the connection currently holding the required lock relinquishes it.
8843** ^This API is only available if the library was compiled with the
8844** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
8845**
8846** See Also: [Using the SQLite Unlock Notification Feature].
8847**
8848** ^Shared-cache locks are released when a database connection concludes
8849** its current transaction, either by committing it or rolling it back.
8850**
8851** ^When a connection (known as the blocked connection) fails to obtain a
8852** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
8853** identity of the database connection (the blocking connection) that
8854** has locked the required resource is stored internally. ^After an
8855** application receives an SQLITE_LOCKED error, it may call the
8856** sqlite3_unlock_notify() method with the blocked connection handle as
8857** the first argument to register for a callback that will be invoked
8858** when the blocking connections current transaction is concluded. ^The
8859** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
8860** call that concludes the blocking connection's transaction.
8861**
8862** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
8863** there is a chance that the blocking connection will have already
8864** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
8865** If this happens, then the specified callback is invoked immediately,
8866** from within the call to sqlite3_unlock_notify().)^
8867**
8868** ^If the blocked connection is attempting to obtain a write-lock on a
8869** shared-cache table, and more than one other connection currently holds
8870** a read-lock on the same table, then SQLite arbitrarily selects one of
8871** the other connections to use as the blocking connection.
8872**
8873** ^(There may be at most one unlock-notify callback registered by a
8874** blocked connection. If sqlite3_unlock_notify() is called when the
8875** blocked connection already has a registered unlock-notify callback,
8876** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
8877** called with a NULL pointer as its second argument, then any existing
8878** unlock-notify callback is canceled. ^The blocked connections
8879** unlock-notify callback may also be canceled by closing the blocked
8880** connection using [sqlite3_close()].
8881**
8882** The unlock-notify callback is not reentrant. If an application invokes
8883** any sqlite3_xxx API functions from within an unlock-notify callback, a
8884** crash or deadlock may be the result.
8885**
8886** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
8887** returns SQLITE_OK.
8888**
8889** <b>Callback Invocation Details</b>
8890**
8891** When an unlock-notify callback is registered, the application provides a
8892** single void* pointer that is passed to the callback when it is invoked.
8893** However, the signature of the callback function allows SQLite to pass
8894** it an array of void* context pointers. The first argument passed to
8895** an unlock-notify callback is a pointer to an array of void* pointers,
8896** and the second is the number of entries in the array.
8897**
8898** When a blocking connection's transaction is concluded, there may be
8899** more than one blocked connection that has registered for an unlock-notify
8900** callback. ^If two or more such blocked connections have specified the
8901** same callback function, then instead of invoking the callback function
8902** multiple times, it is invoked once with the set of void* context pointers
8903** specified by the blocked connections bundled together into an array.
8904** This gives the application an opportunity to prioritize any actions
8905** related to the set of unblocked database connections.
8906**
8907** <b>Deadlock Detection</b>
8908**
8909** Assuming that after registering for an unlock-notify callback a
8910** database waits for the callback to be issued before taking any further
8911** action (a reasonable assumption), then using this API may cause the
8912** application to deadlock. For example, if connection X is waiting for
8913** connection Y's transaction to be concluded, and similarly connection
8914** Y is waiting on connection X's transaction, then neither connection
8915** will proceed and the system may remain deadlocked indefinitely.
8916**
8917** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
8918** detection. ^If a given call to sqlite3_unlock_notify() would put the
8919** system in a deadlocked state, then SQLITE_LOCKED is returned and no
8920** unlock-notify callback is registered. The system is said to be in
8921** a deadlocked state if connection A has registered for an unlock-notify
8922** callback on the conclusion of connection B's transaction, and connection
8923** B has itself registered for an unlock-notify callback when connection
8924** A's transaction is concluded. ^Indirect deadlock is also detected, so
8925** the system is also considered to be deadlocked if connection B has
8926** registered for an unlock-notify callback on the conclusion of connection
8927** C's transaction, where connection C is waiting on connection A. ^Any
8928** number of levels of indirection are allowed.
8929**
8930** <b>The "DROP TABLE" Exception</b>
8931**
8932** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
8933** always appropriate to call sqlite3_unlock_notify(). There is however,
8934** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
8935** SQLite checks if there are any currently executing SELECT statements
8936** that belong to the same connection. If there are, SQLITE_LOCKED is
8937** returned. In this case there is no "blocking connection", so invoking
8938** sqlite3_unlock_notify() results in the unlock-notify callback being
8939** invoked immediately. If the application then re-attempts the "DROP TABLE"
8940** or "DROP INDEX" query, an infinite loop might be the result.
8941**
8942** One way around this problem is to check the extended error code returned
8943** by an sqlite3_step() call. ^(If there is a blocking connection, then the
8944** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
8945** the special "DROP TABLE/INDEX" case, the extended error code is just
8946** SQLITE_LOCKED.)^
8947*/
8948int sqlite3_unlock_notify(
8949  sqlite3 *pBlocked,                          /* Waiting connection */
8950  void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
8951  void *pNotifyArg                            /* Argument to pass to xNotify */
8952);
8953
8954
8955/*
8956** CAPI3REF: String Comparison
8957**
8958** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
8959** and extensions to compare the contents of two buffers containing UTF-8
8960** strings in a case-independent fashion, using the same definition of "case
8961** independence" that SQLite uses internally when comparing identifiers.
8962*/
8963int sqlite3_stricmp(const char *, const char *);
8964int sqlite3_strnicmp(const char *, const char *, int);
8965
8966/*
8967** CAPI3REF: String Globbing
8968*
8969** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
8970** string X matches the [GLOB] pattern P.
8971** ^The definition of [GLOB] pattern matching used in
8972** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
8973** SQL dialect understood by SQLite.  ^The [sqlite3_strglob(P,X)] function
8974** is case sensitive.
8975**
8976** Note that this routine returns zero on a match and non-zero if the strings
8977** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
8978**
8979** See also: [sqlite3_strlike()].
8980*/
8981int sqlite3_strglob(const char *zGlob, const char *zStr);
8982
8983/*
8984** CAPI3REF: String LIKE Matching
8985*
8986** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
8987** string X matches the [LIKE] pattern P with escape character E.
8988** ^The definition of [LIKE] pattern matching used in
8989** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
8990** operator in the SQL dialect understood by SQLite.  ^For "X LIKE P" without
8991** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
8992** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
8993** insensitive - equivalent upper and lower case ASCII characters match
8994** one another.
8995**
8996** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
8997** only ASCII characters are case folded.
8998**
8999** Note that this routine returns zero on a match and non-zero if the strings
9000** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
9001**
9002** See also: [sqlite3_strglob()].
9003*/
9004int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
9005
9006/*
9007** CAPI3REF: Error Logging Interface
9008**
9009** ^The [sqlite3_log()] interface writes a message into the [error log]
9010** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
9011** ^If logging is enabled, the zFormat string and subsequent arguments are
9012** used with [sqlite3_snprintf()] to generate the final output string.
9013**
9014** The sqlite3_log() interface is intended for use by extensions such as
9015** virtual tables, collating functions, and SQL functions.  While there is
9016** nothing to prevent an application from calling sqlite3_log(), doing so
9017** is considered bad form.
9018**
9019** The zFormat string must not be NULL.
9020**
9021** To avoid deadlocks and other threading problems, the sqlite3_log() routine
9022** will not use dynamically allocated memory.  The log message is stored in
9023** a fixed-length buffer on the stack.  If the log message is longer than
9024** a few hundred characters, it will be truncated to the length of the
9025** buffer.
9026*/
9027void sqlite3_log(int iErrCode, const char *zFormat, ...);
9028
9029/*
9030** CAPI3REF: Write-Ahead Log Commit Hook
9031** METHOD: sqlite3
9032**
9033** ^The [sqlite3_wal_hook()] function is used to register a callback that
9034** is invoked each time data is committed to a database in wal mode.
9035**
9036** ^(The callback is invoked by SQLite after the commit has taken place and
9037** the associated write-lock on the database released)^, so the implementation
9038** may read, write or [checkpoint] the database as required.
9039**
9040** ^The first parameter passed to the callback function when it is invoked
9041** is a copy of the third parameter passed to sqlite3_wal_hook() when
9042** registering the callback. ^The second is a copy of the database handle.
9043** ^The third parameter is the name of the database that was written to -
9044** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
9045** is the number of pages currently in the write-ahead log file,
9046** including those that were just committed.
9047**
9048** The callback function should normally return [SQLITE_OK].  ^If an error
9049** code is returned, that error will propagate back up through the
9050** SQLite code base to cause the statement that provoked the callback
9051** to report an error, though the commit will have still occurred. If the
9052** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
9053** that does not correspond to any valid SQLite error code, the results
9054** are undefined.
9055**
9056** A single database handle may have at most a single write-ahead log callback
9057** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
9058** previously registered write-ahead log callback. ^The return value is
9059** a copy of the third parameter from the previous call, if any, or 0.
9060** ^Note that the [sqlite3_wal_autocheckpoint()] interface and the
9061** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
9062** overwrite any prior [sqlite3_wal_hook()] settings.
9063*/
9064void *sqlite3_wal_hook(
9065  sqlite3*,
9066  int(*)(void *,sqlite3*,const char*,int),
9067  void*
9068);
9069
9070/*
9071** CAPI3REF: Configure an auto-checkpoint
9072** METHOD: sqlite3
9073**
9074** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
9075** [sqlite3_wal_hook()] that causes any database on [database connection] D
9076** to automatically [checkpoint]
9077** after committing a transaction if there are N or
9078** more frames in the [write-ahead log] file.  ^Passing zero or
9079** a negative value as the nFrame parameter disables automatic
9080** checkpoints entirely.
9081**
9082** ^The callback registered by this function replaces any existing callback
9083** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
9084** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
9085** configured by this function.
9086**
9087** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
9088** from SQL.
9089**
9090** ^Checkpoints initiated by this mechanism are
9091** [sqlite3_wal_checkpoint_v2|PASSIVE].
9092**
9093** ^Every new [database connection] defaults to having the auto-checkpoint
9094** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
9095** pages.  The use of this interface
9096** is only necessary if the default setting is found to be suboptimal
9097** for a particular application.
9098*/
9099int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
9100
9101/*
9102** CAPI3REF: Checkpoint a database
9103** METHOD: sqlite3
9104**
9105** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
9106** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
9107**
9108** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
9109** [write-ahead log] for database X on [database connection] D to be
9110** transferred into the database file and for the write-ahead log to
9111** be reset.  See the [checkpointing] documentation for addition
9112** information.
9113**
9114** This interface used to be the only way to cause a checkpoint to
9115** occur.  But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
9116** interface was added.  This interface is retained for backwards
9117** compatibility and as a convenience for applications that need to manually
9118** start a callback but which do not need the full power (and corresponding
9119** complication) of [sqlite3_wal_checkpoint_v2()].
9120*/
9121int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
9122
9123/*
9124** CAPI3REF: Checkpoint a database
9125** METHOD: sqlite3
9126**
9127** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
9128** operation on database X of [database connection] D in mode M.  Status
9129** information is written back into integers pointed to by L and C.)^
9130** ^(The M parameter must be a valid [checkpoint mode]:)^
9131**
9132** <dl>
9133** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
9134**   ^Checkpoint as many frames as possible without waiting for any database
9135**   readers or writers to finish, then sync the database file if all frames
9136**   in the log were checkpointed. ^The [busy-handler callback]
9137**   is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
9138**   ^On the other hand, passive mode might leave the checkpoint unfinished
9139**   if there are concurrent readers or writers.
9140**
9141** <dt>SQLITE_CHECKPOINT_FULL<dd>
9142**   ^This mode blocks (it invokes the
9143**   [sqlite3_busy_handler|busy-handler callback]) until there is no
9144**   database writer and all readers are reading from the most recent database
9145**   snapshot. ^It then checkpoints all frames in the log file and syncs the
9146**   database file. ^This mode blocks new database writers while it is pending,
9147**   but new database readers are allowed to continue unimpeded.
9148**
9149** <dt>SQLITE_CHECKPOINT_RESTART<dd>
9150**   ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
9151**   that after checkpointing the log file it blocks (calls the
9152**   [busy-handler callback])
9153**   until all readers are reading from the database file only. ^This ensures
9154**   that the next writer will restart the log file from the beginning.
9155**   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
9156**   database writer attempts while it is pending, but does not impede readers.
9157**
9158** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
9159**   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
9160**   addition that it also truncates the log file to zero bytes just prior
9161**   to a successful return.
9162** </dl>
9163**
9164** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
9165** the log file or to -1 if the checkpoint could not run because
9166** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
9167** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
9168** log file (including any that were already checkpointed before the function
9169** was called) or to -1 if the checkpoint could not run due to an error or
9170** because the database is not in WAL mode. ^Note that upon successful
9171** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
9172** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
9173**
9174** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
9175** any other process is running a checkpoint operation at the same time, the
9176** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
9177** busy-handler configured, it will not be invoked in this case.
9178**
9179** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
9180** exclusive "writer" lock on the database file. ^If the writer lock cannot be
9181** obtained immediately, and a busy-handler is configured, it is invoked and
9182** the writer lock retried until either the busy-handler returns 0 or the lock
9183** is successfully obtained. ^The busy-handler is also invoked while waiting for
9184** database readers as described above. ^If the busy-handler returns 0 before
9185** the writer lock is obtained or while waiting for database readers, the
9186** checkpoint operation proceeds from that point in the same way as
9187** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
9188** without blocking any further. ^SQLITE_BUSY is returned in this case.
9189**
9190** ^If parameter zDb is NULL or points to a zero length string, then the
9191** specified operation is attempted on all WAL databases [attached] to
9192** [database connection] db.  In this case the
9193** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
9194** an SQLITE_BUSY error is encountered when processing one or more of the
9195** attached WAL databases, the operation is still attempted on any remaining
9196** attached databases and SQLITE_BUSY is returned at the end. ^If any other
9197** error occurs while processing an attached database, processing is abandoned
9198** and the error code is returned to the caller immediately. ^If no error
9199** (SQLITE_BUSY or otherwise) is encountered while processing the attached
9200** databases, SQLITE_OK is returned.
9201**
9202** ^If database zDb is the name of an attached database that is not in WAL
9203** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
9204** zDb is not NULL (or a zero length string) and is not the name of any
9205** attached database, SQLITE_ERROR is returned to the caller.
9206**
9207** ^Unless it returns SQLITE_MISUSE,
9208** the sqlite3_wal_checkpoint_v2() interface
9209** sets the error information that is queried by
9210** [sqlite3_errcode()] and [sqlite3_errmsg()].
9211**
9212** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
9213** from SQL.
9214*/
9215int sqlite3_wal_checkpoint_v2(
9216  sqlite3 *db,                    /* Database handle */
9217  const char *zDb,                /* Name of attached database (or NULL) */
9218  int eMode,                      /* SQLITE_CHECKPOINT_* value */
9219  int *pnLog,                     /* OUT: Size of WAL log in frames */
9220  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
9221);
9222
9223/*
9224** CAPI3REF: Checkpoint Mode Values
9225** KEYWORDS: {checkpoint mode}
9226**
9227** These constants define all valid values for the "checkpoint mode" passed
9228** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
9229** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
9230** meaning of each of these checkpoint modes.
9231*/
9232#define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
9233#define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
9234#define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for for readers */
9235#define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */
9236
9237/*
9238** CAPI3REF: Virtual Table Interface Configuration
9239**
9240** This function may be called by either the [xConnect] or [xCreate] method
9241** of a [virtual table] implementation to configure
9242** various facets of the virtual table interface.
9243**
9244** If this interface is invoked outside the context of an xConnect or
9245** xCreate virtual table method then the behavior is undefined.
9246**
9247** In the call sqlite3_vtab_config(D,C,...) the D parameter is the
9248** [database connection] in which the virtual table is being created and
9249** which is passed in as the first argument to the [xConnect] or [xCreate]
9250** method that is invoking sqlite3_vtab_config().  The C parameter is one
9251** of the [virtual table configuration options].  The presence and meaning
9252** of parameters after C depend on which [virtual table configuration option]
9253** is used.
9254*/
9255int sqlite3_vtab_config(sqlite3*, int op, ...);
9256
9257/*
9258** CAPI3REF: Virtual Table Configuration Options
9259** KEYWORDS: {virtual table configuration options}
9260** KEYWORDS: {virtual table configuration option}
9261**
9262** These macros define the various options to the
9263** [sqlite3_vtab_config()] interface that [virtual table] implementations
9264** can use to customize and optimize their behavior.
9265**
9266** <dl>
9267** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]]
9268** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt>
9269** <dd>Calls of the form
9270** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
9271** where X is an integer.  If X is zero, then the [virtual table] whose
9272** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
9273** support constraints.  In this configuration (which is the default) if
9274** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
9275** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
9276** specified as part of the users SQL statement, regardless of the actual
9277** ON CONFLICT mode specified.
9278**
9279** If X is non-zero, then the virtual table implementation guarantees
9280** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
9281** any modifications to internal or persistent data structures have been made.
9282** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
9283** is able to roll back a statement or database transaction, and abandon
9284** or continue processing the current SQL statement as appropriate.
9285** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
9286** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
9287** had been ABORT.
9288**
9289** Virtual table implementations that are required to handle OR REPLACE
9290** must do so within the [xUpdate] method. If a call to the
9291** [sqlite3_vtab_on_conflict()] function indicates that the current ON
9292** CONFLICT policy is REPLACE, the virtual table implementation should
9293** silently replace the appropriate rows within the xUpdate callback and
9294** return SQLITE_OK. Or, if this is not possible, it may return
9295** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
9296** constraint handling.
9297** </dd>
9298**
9299** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt>
9300** <dd>Calls of the form
9301** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the
9302** the [xConnect] or [xCreate] methods of a [virtual table] implmentation
9303** prohibits that virtual table from being used from within triggers and
9304** views.
9305** </dd>
9306**
9307** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt>
9308** <dd>Calls of the form
9309** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the
9310** the [xConnect] or [xCreate] methods of a [virtual table] implmentation
9311** identify that virtual table as being safe to use from within triggers
9312** and views.  Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the
9313** virtual table can do no serious harm even if it is controlled by a
9314** malicious hacker.  Developers should avoid setting the SQLITE_VTAB_INNOCUOUS
9315** flag unless absolutely necessary.
9316** </dd>
9317** </dl>
9318*/
9319#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
9320#define SQLITE_VTAB_INNOCUOUS          2
9321#define SQLITE_VTAB_DIRECTONLY         3
9322
9323/*
9324** CAPI3REF: Determine The Virtual Table Conflict Policy
9325**
9326** This function may only be called from within a call to the [xUpdate] method
9327** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
9328** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
9329** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
9330** of the SQL statement that triggered the call to the [xUpdate] method of the
9331** [virtual table].
9332*/
9333int sqlite3_vtab_on_conflict(sqlite3 *);
9334
9335/*
9336** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
9337**
9338** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
9339** method of a [virtual table], then it might return true if the
9340** column is being fetched as part of an UPDATE operation during which the
9341** column value will not change.  The virtual table implementation can use
9342** this hint as permission to substitute a return value that is less
9343** expensive to compute and that the corresponding
9344** [xUpdate] method understands as a "no-change" value.
9345**
9346** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
9347** the column is not changed by the UPDATE statement, then the xColumn
9348** method can optionally return without setting a result, without calling
9349** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
9350** In that case, [sqlite3_value_nochange(X)] will return true for the
9351** same column in the [xUpdate] method.
9352**
9353** The sqlite3_vtab_nochange() routine is an optimization.  Virtual table
9354** implementations should continue to give a correct answer even if the
9355** sqlite3_vtab_nochange() interface were to always return false.  In the
9356** current implementation, the sqlite3_vtab_nochange() interface does always
9357** returns false for the enhanced [UPDATE FROM] statement.
9358*/
9359int sqlite3_vtab_nochange(sqlite3_context*);
9360
9361/*
9362** CAPI3REF: Determine The Collation For a Virtual Table Constraint
9363**
9364** This function may only be called from within a call to the [xBestIndex]
9365** method of a [virtual table].
9366**
9367** The first argument must be the sqlite3_index_info object that is the
9368** first parameter to the xBestIndex() method. The second argument must be
9369** an index into the aConstraint[] array belonging to the sqlite3_index_info
9370** structure passed to xBestIndex. This function returns a pointer to a buffer
9371** containing the name of the collation sequence for the corresponding
9372** constraint.
9373*/
9374SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
9375
9376/*
9377** CAPI3REF: Conflict resolution modes
9378** KEYWORDS: {conflict resolution mode}
9379**
9380** These constants are returned by [sqlite3_vtab_on_conflict()] to
9381** inform a [virtual table] implementation what the [ON CONFLICT] mode
9382** is for the SQL statement being evaluated.
9383**
9384** Note that the [SQLITE_IGNORE] constant is also used as a potential
9385** return value from the [sqlite3_set_authorizer()] callback and that
9386** [SQLITE_ABORT] is also a [result code].
9387*/
9388#define SQLITE_ROLLBACK 1
9389/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
9390#define SQLITE_FAIL     3
9391/* #define SQLITE_ABORT 4  // Also an error code */
9392#define SQLITE_REPLACE  5
9393
9394/*
9395** CAPI3REF: Prepared Statement Scan Status Opcodes
9396** KEYWORDS: {scanstatus options}
9397**
9398** The following constants can be used for the T parameter to the
9399** [sqlite3_stmt_scanstatus(S,X,T,V)] interface.  Each constant designates a
9400** different metric for sqlite3_stmt_scanstatus() to return.
9401**
9402** When the value returned to V is a string, space to hold that string is
9403** managed by the prepared statement S and will be automatically freed when
9404** S is finalized.
9405**
9406** <dl>
9407** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
9408** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be
9409** set to the total number of times that the X-th loop has run.</dd>
9410**
9411** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
9412** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set
9413** to the total number of rows examined by all iterations of the X-th loop.</dd>
9414**
9415** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
9416** <dd>^The "double" variable pointed to by the V parameter will be set to the
9417** query planner's estimate for the average number of rows output from each
9418** iteration of the X-th loop.  If the query planner's estimates was accurate,
9419** then this value will approximate the quotient NVISIT/NLOOP and the
9420** product of this value for all prior loops with the same SELECTID will
9421** be the NLOOP value for the current loop.
9422**
9423** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
9424** <dd>^The "const char *" variable pointed to by the V parameter will be set
9425** to a zero-terminated UTF-8 string containing the name of the index or table
9426** used for the X-th loop.
9427**
9428** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
9429** <dd>^The "const char *" variable pointed to by the V parameter will be set
9430** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
9431** description for the X-th loop.
9432**
9433** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
9434** <dd>^The "int" variable pointed to by the V parameter will be set to the
9435** "select-id" for the X-th loop.  The select-id identifies which query or
9436** subquery the loop is part of.  The main query has a select-id of zero.
9437** The select-id is the same value as is output in the first column
9438** of an [EXPLAIN QUERY PLAN] query.
9439** </dl>
9440*/
9441#define SQLITE_SCANSTAT_NLOOP    0
9442#define SQLITE_SCANSTAT_NVISIT   1
9443#define SQLITE_SCANSTAT_EST      2
9444#define SQLITE_SCANSTAT_NAME     3
9445#define SQLITE_SCANSTAT_EXPLAIN  4
9446#define SQLITE_SCANSTAT_SELECTID 5
9447
9448/*
9449** CAPI3REF: Prepared Statement Scan Status
9450** METHOD: sqlite3_stmt
9451**
9452** This interface returns information about the predicted and measured
9453** performance for pStmt.  Advanced applications can use this
9454** interface to compare the predicted and the measured performance and
9455** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
9456**
9457** Since this interface is expected to be rarely used, it is only
9458** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
9459** compile-time option.
9460**
9461** The "iScanStatusOp" parameter determines which status information to return.
9462** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
9463** of this interface is undefined.
9464** ^The requested measurement is written into a variable pointed to by
9465** the "pOut" parameter.
9466** Parameter "idx" identifies the specific loop to retrieve statistics for.
9467** Loops are numbered starting from zero. ^If idx is out of range - less than
9468** zero or greater than or equal to the total number of loops used to implement
9469** the statement - a non-zero value is returned and the variable that pOut
9470** points to is unchanged.
9471**
9472** ^Statistics might not be available for all loops in all statements. ^In cases
9473** where there exist loops with no available statistics, this function behaves
9474** as if the loop did not exist - it returns non-zero and leave the variable
9475** that pOut points to unchanged.
9476**
9477** See also: [sqlite3_stmt_scanstatus_reset()]
9478*/
9479int sqlite3_stmt_scanstatus(
9480  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
9481  int idx,                  /* Index of loop to report on */
9482  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
9483  void *pOut                /* Result written here */
9484);
9485
9486/*
9487** CAPI3REF: Zero Scan-Status Counters
9488** METHOD: sqlite3_stmt
9489**
9490** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
9491**
9492** This API is only available if the library is built with pre-processor
9493** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
9494*/
9495void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
9496
9497/*
9498** CAPI3REF: Flush caches to disk mid-transaction
9499** METHOD: sqlite3
9500**
9501** ^If a write-transaction is open on [database connection] D when the
9502** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
9503** pages in the pager-cache that are not currently in use are written out
9504** to disk. A dirty page may be in use if a database cursor created by an
9505** active SQL statement is reading from it, or if it is page 1 of a database
9506** file (page 1 is always "in use").  ^The [sqlite3_db_cacheflush(D)]
9507** interface flushes caches for all schemas - "main", "temp", and
9508** any [attached] databases.
9509**
9510** ^If this function needs to obtain extra database locks before dirty pages
9511** can be flushed to disk, it does so. ^If those locks cannot be obtained
9512** immediately and there is a busy-handler callback configured, it is invoked
9513** in the usual manner. ^If the required lock still cannot be obtained, then
9514** the database is skipped and an attempt made to flush any dirty pages
9515** belonging to the next (if any) database. ^If any databases are skipped
9516** because locks cannot be obtained, but no other error occurs, this
9517** function returns SQLITE_BUSY.
9518**
9519** ^If any other error occurs while flushing dirty pages to disk (for
9520** example an IO error or out-of-memory condition), then processing is
9521** abandoned and an SQLite [error code] is returned to the caller immediately.
9522**
9523** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
9524**
9525** ^This function does not set the database handle error code or message
9526** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
9527*/
9528int sqlite3_db_cacheflush(sqlite3*);
9529
9530/*
9531** CAPI3REF: The pre-update hook.
9532** METHOD: sqlite3
9533**
9534** ^These interfaces are only available if SQLite is compiled using the
9535** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
9536**
9537** ^The [sqlite3_preupdate_hook()] interface registers a callback function
9538** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
9539** on a database table.
9540** ^At most one preupdate hook may be registered at a time on a single
9541** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
9542** the previous setting.
9543** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
9544** with a NULL pointer as the second parameter.
9545** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
9546** the first parameter to callbacks.
9547**
9548** ^The preupdate hook only fires for changes to real database tables; the
9549** preupdate hook is not invoked for changes to [virtual tables] or to
9550** system tables like sqlite_sequence or sqlite_stat1.
9551**
9552** ^The second parameter to the preupdate callback is a pointer to
9553** the [database connection] that registered the preupdate hook.
9554** ^The third parameter to the preupdate callback is one of the constants
9555** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
9556** kind of update operation that is about to occur.
9557** ^(The fourth parameter to the preupdate callback is the name of the
9558** database within the database connection that is being modified.  This
9559** will be "main" for the main database or "temp" for TEMP tables or
9560** the name given after the AS keyword in the [ATTACH] statement for attached
9561** databases.)^
9562** ^The fifth parameter to the preupdate callback is the name of the
9563** table that is being modified.
9564**
9565** For an UPDATE or DELETE operation on a [rowid table], the sixth
9566** parameter passed to the preupdate callback is the initial [rowid] of the
9567** row being modified or deleted. For an INSERT operation on a rowid table,
9568** or any operation on a WITHOUT ROWID table, the value of the sixth
9569** parameter is undefined. For an INSERT or UPDATE on a rowid table the
9570** seventh parameter is the final rowid value of the row being inserted
9571** or updated. The value of the seventh parameter passed to the callback
9572** function is not defined for operations on WITHOUT ROWID tables, or for
9573** DELETE operations on rowid tables.
9574**
9575** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
9576** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
9577** provide additional information about a preupdate event. These routines
9578** may only be called from within a preupdate callback.  Invoking any of
9579** these routines from outside of a preupdate callback or with a
9580** [database connection] pointer that is different from the one supplied
9581** to the preupdate callback results in undefined and probably undesirable
9582** behavior.
9583**
9584** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
9585** in the row that is being inserted, updated, or deleted.
9586**
9587** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
9588** a [protected sqlite3_value] that contains the value of the Nth column of
9589** the table row before it is updated.  The N parameter must be between 0
9590** and one less than the number of columns or the behavior will be
9591** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
9592** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
9593** behavior is undefined.  The [sqlite3_value] that P points to
9594** will be destroyed when the preupdate callback returns.
9595**
9596** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
9597** a [protected sqlite3_value] that contains the value of the Nth column of
9598** the table row after it is updated.  The N parameter must be between 0
9599** and one less than the number of columns or the behavior will be
9600** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
9601** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
9602** behavior is undefined.  The [sqlite3_value] that P points to
9603** will be destroyed when the preupdate callback returns.
9604**
9605** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
9606** callback was invoked as a result of a direct insert, update, or delete
9607** operation; or 1 for inserts, updates, or deletes invoked by top-level
9608** triggers; or 2 for changes resulting from triggers called by top-level
9609** triggers; and so forth.
9610**
9611** When the [sqlite3_blob_write()] API is used to update a blob column,
9612** the pre-update hook is invoked with SQLITE_DELETE. This is because the
9613** in this case the new values are not available. In this case, when a
9614** callback made with op==SQLITE_DELETE is actuall a write using the
9615** sqlite3_blob_write() API, the [sqlite3_preupdate_blobwrite()] returns
9616** the index of the column being written. In other cases, where the
9617** pre-update hook is being invoked for some other reason, including a
9618** regular DELETE, sqlite3_preupdate_blobwrite() returns -1.
9619**
9620** See also:  [sqlite3_update_hook()]
9621*/
9622#if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
9623void *sqlite3_preupdate_hook(
9624  sqlite3 *db,
9625  void(*xPreUpdate)(
9626    void *pCtx,                   /* Copy of third arg to preupdate_hook() */
9627    sqlite3 *db,                  /* Database handle */
9628    int op,                       /* SQLITE_UPDATE, DELETE or INSERT */
9629    char const *zDb,              /* Database name */
9630    char const *zName,            /* Table name */
9631    sqlite3_int64 iKey1,          /* Rowid of row about to be deleted/updated */
9632    sqlite3_int64 iKey2           /* New rowid value (for a rowid UPDATE) */
9633  ),
9634  void*
9635);
9636int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
9637int sqlite3_preupdate_count(sqlite3 *);
9638int sqlite3_preupdate_depth(sqlite3 *);
9639int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
9640int sqlite3_preupdate_blobwrite(sqlite3 *);
9641#endif
9642
9643/*
9644** CAPI3REF: Low-level system error code
9645** METHOD: sqlite3
9646**
9647** ^Attempt to return the underlying operating system error code or error
9648** number that caused the most recent I/O error or failure to open a file.
9649** The return value is OS-dependent.  For example, on unix systems, after
9650** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
9651** called to get back the underlying "errno" that caused the problem, such
9652** as ENOSPC, EAUTH, EISDIR, and so forth.
9653*/
9654int sqlite3_system_errno(sqlite3*);
9655
9656/*
9657** CAPI3REF: Database Snapshot
9658** KEYWORDS: {snapshot} {sqlite3_snapshot}
9659**
9660** An instance of the snapshot object records the state of a [WAL mode]
9661** database for some specific point in history.
9662**
9663** In [WAL mode], multiple [database connections] that are open on the
9664** same database file can each be reading a different historical version
9665** of the database file.  When a [database connection] begins a read
9666** transaction, that connection sees an unchanging copy of the database
9667** as it existed for the point in time when the transaction first started.
9668** Subsequent changes to the database from other connections are not seen
9669** by the reader until a new read transaction is started.
9670**
9671** The sqlite3_snapshot object records state information about an historical
9672** version of the database file so that it is possible to later open a new read
9673** transaction that sees that historical version of the database rather than
9674** the most recent version.
9675*/
9676typedef struct sqlite3_snapshot {
9677  unsigned char hidden[48];
9678} sqlite3_snapshot;
9679
9680/*
9681** CAPI3REF: Record A Database Snapshot
9682** CONSTRUCTOR: sqlite3_snapshot
9683**
9684** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
9685** new [sqlite3_snapshot] object that records the current state of
9686** schema S in database connection D.  ^On success, the
9687** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
9688** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
9689** If there is not already a read-transaction open on schema S when
9690** this function is called, one is opened automatically.
9691**
9692** The following must be true for this function to succeed. If any of
9693** the following statements are false when sqlite3_snapshot_get() is
9694** called, SQLITE_ERROR is returned. The final value of *P is undefined
9695** in this case.
9696**
9697** <ul>
9698**   <li> The database handle must not be in [autocommit mode].
9699**
9700**   <li> Schema S of [database connection] D must be a [WAL mode] database.
9701**
9702**   <li> There must not be a write transaction open on schema S of database
9703**        connection D.
9704**
9705**   <li> One or more transactions must have been written to the current wal
9706**        file since it was created on disk (by any connection). This means
9707**        that a snapshot cannot be taken on a wal mode database with no wal
9708**        file immediately after it is first opened. At least one transaction
9709**        must be written to it first.
9710** </ul>
9711**
9712** This function may also return SQLITE_NOMEM.  If it is called with the
9713** database handle in autocommit mode but fails for some other reason,
9714** whether or not a read transaction is opened on schema S is undefined.
9715**
9716** The [sqlite3_snapshot] object returned from a successful call to
9717** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
9718** to avoid a memory leak.
9719**
9720** The [sqlite3_snapshot_get()] interface is only available when the
9721** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
9722*/
9723SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
9724  sqlite3 *db,
9725  const char *zSchema,
9726  sqlite3_snapshot **ppSnapshot
9727);
9728
9729/*
9730** CAPI3REF: Start a read transaction on an historical snapshot
9731** METHOD: sqlite3_snapshot
9732**
9733** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read
9734** transaction or upgrades an existing one for schema S of
9735** [database connection] D such that the read transaction refers to
9736** historical [snapshot] P, rather than the most recent change to the
9737** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK
9738** on success or an appropriate [error code] if it fails.
9739**
9740** ^In order to succeed, the database connection must not be in
9741** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there
9742** is already a read transaction open on schema S, then the database handle
9743** must have no active statements (SELECT statements that have been passed
9744** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()).
9745** SQLITE_ERROR is returned if either of these conditions is violated, or
9746** if schema S does not exist, or if the snapshot object is invalid.
9747**
9748** ^A call to sqlite3_snapshot_open() will fail to open if the specified
9749** snapshot has been overwritten by a [checkpoint]. In this case
9750** SQLITE_ERROR_SNAPSHOT is returned.
9751**
9752** If there is already a read transaction open when this function is
9753** invoked, then the same read transaction remains open (on the same
9754** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT
9755** is returned. If another error code - for example SQLITE_PROTOCOL or an
9756** SQLITE_IOERR error code - is returned, then the final state of the
9757** read transaction is undefined. If SQLITE_OK is returned, then the
9758** read transaction is now open on database snapshot P.
9759**
9760** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
9761** database connection D does not know that the database file for
9762** schema S is in [WAL mode].  A database connection might not know
9763** that the database file is in [WAL mode] if there has been no prior
9764** I/O on that database connection, or if the database entered [WAL mode]
9765** after the most recent I/O on the database connection.)^
9766** (Hint: Run "[PRAGMA application_id]" against a newly opened
9767** database connection in order to make it ready to use snapshots.)
9768**
9769** The [sqlite3_snapshot_open()] interface is only available when the
9770** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
9771*/
9772SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
9773  sqlite3 *db,
9774  const char *zSchema,
9775  sqlite3_snapshot *pSnapshot
9776);
9777
9778/*
9779** CAPI3REF: Destroy a snapshot
9780** DESTRUCTOR: sqlite3_snapshot
9781**
9782** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
9783** The application must eventually free every [sqlite3_snapshot] object
9784** using this routine to avoid a memory leak.
9785**
9786** The [sqlite3_snapshot_free()] interface is only available when the
9787** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
9788*/
9789SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
9790
9791/*
9792** CAPI3REF: Compare the ages of two snapshot handles.
9793** METHOD: sqlite3_snapshot
9794**
9795** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
9796** of two valid snapshot handles.
9797**
9798** If the two snapshot handles are not associated with the same database
9799** file, the result of the comparison is undefined.
9800**
9801** Additionally, the result of the comparison is only valid if both of the
9802** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
9803** last time the wal file was deleted. The wal file is deleted when the
9804** database is changed back to rollback mode or when the number of database
9805** clients drops to zero. If either snapshot handle was obtained before the
9806** wal file was last deleted, the value returned by this function
9807** is undefined.
9808**
9809** Otherwise, this API returns a negative value if P1 refers to an older
9810** snapshot than P2, zero if the two handles refer to the same database
9811** snapshot, and a positive value if P1 is a newer snapshot than P2.
9812**
9813** This interface is only available if SQLite is compiled with the
9814** [SQLITE_ENABLE_SNAPSHOT] option.
9815*/
9816SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
9817  sqlite3_snapshot *p1,
9818  sqlite3_snapshot *p2
9819);
9820
9821/*
9822** CAPI3REF: Recover snapshots from a wal file
9823** METHOD: sqlite3_snapshot
9824**
9825** If a [WAL file] remains on disk after all database connections close
9826** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control]
9827** or because the last process to have the database opened exited without
9828** calling [sqlite3_close()]) and a new connection is subsequently opened
9829** on that database and [WAL file], the [sqlite3_snapshot_open()] interface
9830** will only be able to open the last transaction added to the WAL file
9831** even though the WAL file contains other valid transactions.
9832**
9833** This function attempts to scan the WAL file associated with database zDb
9834** of database handle db and make all valid snapshots available to
9835** sqlite3_snapshot_open(). It is an error if there is already a read
9836** transaction open on the database, or if the database is not a WAL mode
9837** database.
9838**
9839** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
9840**
9841** This interface is only available if SQLite is compiled with the
9842** [SQLITE_ENABLE_SNAPSHOT] option.
9843*/
9844SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
9845
9846/*
9847** CAPI3REF: Serialize a database
9848**
9849** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory
9850** that is a serialization of the S database on [database connection] D.
9851** If P is not a NULL pointer, then the size of the database in bytes
9852** is written into *P.
9853**
9854** For an ordinary on-disk database file, the serialization is just a
9855** copy of the disk file.  For an in-memory database or a "TEMP" database,
9856** the serialization is the same sequence of bytes which would be written
9857** to disk if that database where backed up to disk.
9858**
9859** The usual case is that sqlite3_serialize() copies the serialization of
9860** the database into memory obtained from [sqlite3_malloc64()] and returns
9861** a pointer to that memory.  The caller is responsible for freeing the
9862** returned value to avoid a memory leak.  However, if the F argument
9863** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
9864** are made, and the sqlite3_serialize() function will return a pointer
9865** to the contiguous memory representation of the database that SQLite
9866** is currently using for that database, or NULL if the no such contiguous
9867** memory representation of the database exists.  A contiguous memory
9868** representation of the database will usually only exist if there has
9869** been a prior call to [sqlite3_deserialize(D,S,...)] with the same
9870** values of D and S.
9871** The size of the database is written into *P even if the
9872** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
9873** of the database exists.
9874**
9875** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
9876** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
9877** allocation error occurs.
9878**
9879** This interface is omitted if SQLite is compiled with the
9880** [SQLITE_OMIT_DESERIALIZE] option.
9881*/
9882unsigned char *sqlite3_serialize(
9883  sqlite3 *db,           /* The database connection */
9884  const char *zSchema,   /* Which DB to serialize. ex: "main", "temp", ... */
9885  sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */
9886  unsigned int mFlags    /* Zero or more SQLITE_SERIALIZE_* flags */
9887);
9888
9889/*
9890** CAPI3REF: Flags for sqlite3_serialize
9891**
9892** Zero or more of the following constants can be OR-ed together for
9893** the F argument to [sqlite3_serialize(D,S,P,F)].
9894**
9895** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return
9896** a pointer to contiguous in-memory database that it is currently using,
9897** without making a copy of the database.  If SQLite is not currently using
9898** a contiguous in-memory database, then this option causes
9899** [sqlite3_serialize()] to return a NULL pointer.  SQLite will only be
9900** using a contiguous in-memory database if it has been initialized by a
9901** prior call to [sqlite3_deserialize()].
9902*/
9903#define SQLITE_SERIALIZE_NOCOPY 0x001   /* Do no memory allocations */
9904
9905/*
9906** CAPI3REF: Deserialize a database
9907**
9908** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
9909** [database connection] D to disconnect from database S and then
9910** reopen S as an in-memory database based on the serialization contained
9911** in P.  The serialized database P is N bytes in size.  M is the size of
9912** the buffer P, which might be larger than N.  If M is larger than N, and
9913** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
9914** permitted to add content to the in-memory database as long as the total
9915** size does not exceed M bytes.
9916**
9917** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
9918** invoke sqlite3_free() on the serialization buffer when the database
9919** connection closes.  If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
9920** SQLite will try to increase the buffer size using sqlite3_realloc64()
9921** if writes on the database cause it to grow larger than M bytes.
9922**
9923** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
9924** database is currently in a read transaction or is involved in a backup
9925** operation.
9926**
9927** It is not possible to deserialized into the TEMP database.  If the
9928** S argument to sqlite3_deserialize(D,S,P,N,M,F) is "temp" then the
9929** function returns SQLITE_ERROR.
9930**
9931** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
9932** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
9933** [sqlite3_free()] is invoked on argument P prior to returning.
9934**
9935** This interface is omitted if SQLite is compiled with the
9936** [SQLITE_OMIT_DESERIALIZE] option.
9937*/
9938int sqlite3_deserialize(
9939  sqlite3 *db,            /* The database connection */
9940  const char *zSchema,    /* Which DB to reopen with the deserialization */
9941  unsigned char *pData,   /* The serialized database content */
9942  sqlite3_int64 szDb,     /* Number bytes in the deserialization */
9943  sqlite3_int64 szBuf,    /* Total size of buffer pData[] */
9944  unsigned mFlags         /* Zero or more SQLITE_DESERIALIZE_* flags */
9945);
9946
9947/*
9948** CAPI3REF: Flags for sqlite3_deserialize()
9949**
9950** The following are allowed values for 6th argument (the F argument) to
9951** the [sqlite3_deserialize(D,S,P,N,M,F)] interface.
9952**
9953** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
9954** in the P argument is held in memory obtained from [sqlite3_malloc64()]
9955** and that SQLite should take ownership of this memory and automatically
9956** free it when it has finished using it.  Without this flag, the caller
9957** is responsible for freeing any dynamically allocated memory.
9958**
9959** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
9960** grow the size of the database using calls to [sqlite3_realloc64()].  This
9961** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
9962** Without this flag, the deserialized database cannot increase in size beyond
9963** the number of bytes specified by the M parameter.
9964**
9965** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
9966** should be treated as read-only.
9967*/
9968#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
9969#define SQLITE_DESERIALIZE_RESIZEABLE  2 /* Resize using sqlite3_realloc64() */
9970#define SQLITE_DESERIALIZE_READONLY    4 /* Database is read-only */
9971
9972/*
9973** Undo the hack that converts floating point types to integer for
9974** builds on processors without floating point support.
9975*/
9976#ifdef SQLITE_OMIT_FLOATING_POINT
9977# undef double
9978#endif
9979
9980#ifdef __cplusplus
9981}  /* End of the 'extern "C"' block */
9982#endif
9983#endif /* SQLITE3_H */
9984