xref: /freebsd/contrib/sqlite3/sqlite3.h (revision 2b833162)
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
41 extern "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        "3.41.0"
150 #define SQLITE_VERSION_NUMBER 3041000
151 #define SQLITE_SOURCE_ID      "2023-02-21 18:09:37 05941c2a04037fc3ed2ffae11f5d2260706f89431f463518740f72ada350866d"
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 */
185 SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
186 SQLITE_API const char *sqlite3_libversion(void);
187 SQLITE_API const char *sqlite3_sourceid(void);
188 SQLITE_API int 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
213 SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
214 SQLITE_API const 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 */
256 SQLITE_API int 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 */
272 typedef 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
304 typedef sqlite_int64 sqlite3_int64;
305 typedef 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 */
353 SQLITE_API int sqlite3_close(sqlite3*);
354 SQLITE_API int 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 */
361 typedef 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 */
425 SQLITE_API int 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_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
543 #define SQLITE_CORRUPT_SEQUENCE        (SQLITE_CORRUPT | (2<<8))
544 #define SQLITE_CORRUPT_INDEX           (SQLITE_CORRUPT | (3<<8))
545 #define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
546 #define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
547 #define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
548 #define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
549 #define SQLITE_READONLY_CANTINIT       (SQLITE_READONLY | (5<<8))
550 #define SQLITE_READONLY_DIRECTORY      (SQLITE_READONLY | (6<<8))
551 #define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
552 #define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
553 #define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
554 #define SQLITE_CONSTRAINT_FOREIGNKEY   (SQLITE_CONSTRAINT | (3<<8))
555 #define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
556 #define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
557 #define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
558 #define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
559 #define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
560 #define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
561 #define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
562 #define SQLITE_CONSTRAINT_PINNED       (SQLITE_CONSTRAINT |(11<<8))
563 #define SQLITE_CONSTRAINT_DATATYPE     (SQLITE_CONSTRAINT |(12<<8))
564 #define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
565 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
566 #define SQLITE_NOTICE_RBU              (SQLITE_NOTICE | (3<<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)) /* internal use only */
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 ** Only those flags marked as "Ok for sqlite3_open_v2()" may be
580 ** used as the third argument to the [sqlite3_open_v2()] interface.
581 ** The other flags have historically been ignored by sqlite3_open_v2(),
582 ** though future versions of SQLite might change so that an error is
583 ** raised if any of the disallowed bits are passed into sqlite3_open_v2().
584 ** Applications should not depend on the historical behavior.
585 **
586 ** Note in particular that passing the SQLITE_OPEN_EXCLUSIVE flag into
587 ** [sqlite3_open_v2()] does *not* cause the underlying database file
588 ** to be opened using O_EXCL.  Passing SQLITE_OPEN_EXCLUSIVE into
589 ** [sqlite3_open_v2()] has historically be a no-op and might become an
590 ** error in future versions of SQLite.
591 */
592 #define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
593 #define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
594 #define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
595 #define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
596 #define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
597 #define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
598 #define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
599 #define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
600 #define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
601 #define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
602 #define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
603 #define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
604 #define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
605 #define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
606 #define SQLITE_OPEN_SUPER_JOURNAL    0x00004000  /* VFS only */
607 #define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
608 #define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
609 #define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
610 #define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
611 #define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
612 #define SQLITE_OPEN_NOFOLLOW         0x01000000  /* Ok for sqlite3_open_v2() */
613 #define SQLITE_OPEN_EXRESCODE        0x02000000  /* Extended result codes */
614 
615 /* Reserved:                         0x00F00000 */
616 /* Legacy compatibility: */
617 #define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
618 
619 
620 /*
621 ** CAPI3REF: Device Characteristics
622 **
623 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
624 ** object returns an integer which is a vector of these
625 ** bit values expressing I/O characteristics of the mass storage
626 ** device that holds the file that the [sqlite3_io_methods]
627 ** refers to.
628 **
629 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
630 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
631 ** mean that writes of blocks that are nnn bytes in size and
632 ** are aligned to an address which is an integer multiple of
633 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
634 ** that when data is appended to a file, the data is appended
635 ** first then the size of the file is extended, never the other
636 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
637 ** information is written to disk in the same order as calls
638 ** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
639 ** after reboot following a crash or power loss, the only bytes in a
640 ** file that were written at the application level might have changed
641 ** and that adjacent bytes, even bytes within the same sector are
642 ** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
643 ** flag indicates that a file cannot be deleted when open.  The
644 ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
645 ** read-only media and cannot be changed even by processes with
646 ** elevated privileges.
647 **
648 ** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
649 ** filesystem supports doing multiple write operations atomically when those
650 ** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
651 ** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
652 */
653 #define SQLITE_IOCAP_ATOMIC                 0x00000001
654 #define SQLITE_IOCAP_ATOMIC512              0x00000002
655 #define SQLITE_IOCAP_ATOMIC1K               0x00000004
656 #define SQLITE_IOCAP_ATOMIC2K               0x00000008
657 #define SQLITE_IOCAP_ATOMIC4K               0x00000010
658 #define SQLITE_IOCAP_ATOMIC8K               0x00000020
659 #define SQLITE_IOCAP_ATOMIC16K              0x00000040
660 #define SQLITE_IOCAP_ATOMIC32K              0x00000080
661 #define SQLITE_IOCAP_ATOMIC64K              0x00000100
662 #define SQLITE_IOCAP_SAFE_APPEND            0x00000200
663 #define SQLITE_IOCAP_SEQUENTIAL             0x00000400
664 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
665 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
666 #define SQLITE_IOCAP_IMMUTABLE              0x00002000
667 #define SQLITE_IOCAP_BATCH_ATOMIC           0x00004000
668 
669 /*
670 ** CAPI3REF: File Locking Levels
671 **
672 ** SQLite uses one of these integer values as the second
673 ** argument to calls it makes to the xLock() and xUnlock() methods
674 ** of an [sqlite3_io_methods] object.  These values are ordered from
675 ** lest restrictive to most restrictive.
676 **
677 ** The argument to xLock() is always SHARED or higher.  The argument to
678 ** xUnlock is either SHARED or NONE.
679 */
680 #define SQLITE_LOCK_NONE          0       /* xUnlock() only */
681 #define SQLITE_LOCK_SHARED        1       /* xLock() or xUnlock() */
682 #define SQLITE_LOCK_RESERVED      2       /* xLock() only */
683 #define SQLITE_LOCK_PENDING       3       /* xLock() only */
684 #define SQLITE_LOCK_EXCLUSIVE     4       /* xLock() only */
685 
686 /*
687 ** CAPI3REF: Synchronization Type Flags
688 **
689 ** When SQLite invokes the xSync() method of an
690 ** [sqlite3_io_methods] object it uses a combination of
691 ** these integer values as the second argument.
692 **
693 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
694 ** sync operation only needs to flush data to mass storage.  Inode
695 ** information need not be flushed. If the lower four bits of the flag
696 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
697 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
698 ** to use Mac OS X style fullsync instead of fsync().
699 **
700 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
701 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
702 ** settings.  The [synchronous pragma] determines when calls to the
703 ** xSync VFS method occur and applies uniformly across all platforms.
704 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
705 ** energetic or rigorous or forceful the sync operations are and
706 ** only make a difference on Mac OSX for the default SQLite code.
707 ** (Third-party VFS implementations might also make the distinction
708 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
709 ** operating systems natively supported by SQLite, only Mac OSX
710 ** cares about the difference.)
711 */
712 #define SQLITE_SYNC_NORMAL        0x00002
713 #define SQLITE_SYNC_FULL          0x00003
714 #define SQLITE_SYNC_DATAONLY      0x00010
715 
716 /*
717 ** CAPI3REF: OS Interface Open File Handle
718 **
719 ** An [sqlite3_file] object represents an open file in the
720 ** [sqlite3_vfs | OS interface layer].  Individual OS interface
721 ** implementations will
722 ** want to subclass this object by appending additional fields
723 ** for their own use.  The pMethods entry is a pointer to an
724 ** [sqlite3_io_methods] object that defines methods for performing
725 ** I/O operations on the open file.
726 */
727 typedef struct sqlite3_file sqlite3_file;
728 struct sqlite3_file {
729   const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
730 };
731 
732 /*
733 ** CAPI3REF: OS Interface File Virtual Methods Object
734 **
735 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
736 ** [sqlite3_file] object (or, more commonly, a subclass of the
737 ** [sqlite3_file] object) with a pointer to an instance of this object.
738 ** This object defines the methods used to perform various operations
739 ** against the open file represented by the [sqlite3_file] object.
740 **
741 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
742 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
743 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
744 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
745 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
746 ** to NULL.
747 **
748 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
749 ** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
750 ** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
751 ** flag may be ORed in to indicate that only the data of the file
752 ** and not its inode needs to be synced.
753 **
754 ** The integer values to xLock() and xUnlock() are one of
755 ** <ul>
756 ** <li> [SQLITE_LOCK_NONE],
757 ** <li> [SQLITE_LOCK_SHARED],
758 ** <li> [SQLITE_LOCK_RESERVED],
759 ** <li> [SQLITE_LOCK_PENDING], or
760 ** <li> [SQLITE_LOCK_EXCLUSIVE].
761 ** </ul>
762 ** xLock() upgrades the database file lock.  In other words, xLock() moves the
763 ** database file lock in the direction NONE toward EXCLUSIVE. The argument to
764 ** xLock() is always on of SHARED, RESERVED, PENDING, or EXCLUSIVE, never
765 ** SQLITE_LOCK_NONE.  If the database file lock is already at or above the
766 ** requested lock, then the call to xLock() is a no-op.
767 ** xUnlock() downgrades the database file lock to either SHARED or NONE.
768 *  If the lock is already at or below the requested lock state, then the call
769 ** to xUnlock() is a no-op.
770 ** The xCheckReservedLock() method checks whether any database connection,
771 ** either in this process or in some other process, is holding a RESERVED,
772 ** PENDING, or EXCLUSIVE lock on the file.  It returns true
773 ** if such a lock exists and false otherwise.
774 **
775 ** The xFileControl() method is a generic interface that allows custom
776 ** VFS implementations to directly control an open file using the
777 ** [sqlite3_file_control()] interface.  The second "op" argument is an
778 ** integer opcode.  The third argument is a generic pointer intended to
779 ** point to a structure that may contain arguments or space in which to
780 ** write return values.  Potential uses for xFileControl() might be
781 ** functions to enable blocking locks with timeouts, to change the
782 ** locking strategy (for example to use dot-file locks), to inquire
783 ** about the status of a lock, or to break stale locks.  The SQLite
784 ** core reserves all opcodes less than 100 for its own use.
785 ** A [file control opcodes | list of opcodes] less than 100 is available.
786 ** Applications that define a custom xFileControl method should use opcodes
787 ** greater than 100 to avoid conflicts.  VFS implementations should
788 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
789 ** recognize.
790 **
791 ** The xSectorSize() method returns the sector size of the
792 ** device that underlies the file.  The sector size is the
793 ** minimum write that can be performed without disturbing
794 ** other bytes in the file.  The xDeviceCharacteristics()
795 ** method returns a bit vector describing behaviors of the
796 ** underlying device:
797 **
798 ** <ul>
799 ** <li> [SQLITE_IOCAP_ATOMIC]
800 ** <li> [SQLITE_IOCAP_ATOMIC512]
801 ** <li> [SQLITE_IOCAP_ATOMIC1K]
802 ** <li> [SQLITE_IOCAP_ATOMIC2K]
803 ** <li> [SQLITE_IOCAP_ATOMIC4K]
804 ** <li> [SQLITE_IOCAP_ATOMIC8K]
805 ** <li> [SQLITE_IOCAP_ATOMIC16K]
806 ** <li> [SQLITE_IOCAP_ATOMIC32K]
807 ** <li> [SQLITE_IOCAP_ATOMIC64K]
808 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
809 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
810 ** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
811 ** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
812 ** <li> [SQLITE_IOCAP_IMMUTABLE]
813 ** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
814 ** </ul>
815 **
816 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
817 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
818 ** mean that writes of blocks that are nnn bytes in size and
819 ** are aligned to an address which is an integer multiple of
820 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
821 ** that when data is appended to a file, the data is appended
822 ** first then the size of the file is extended, never the other
823 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
824 ** information is written to disk in the same order as calls
825 ** to xWrite().
826 **
827 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
828 ** in the unread portions of the buffer with zeros.  A VFS that
829 ** fails to zero-fill short reads might seem to work.  However,
830 ** failure to zero-fill short reads will eventually lead to
831 ** database corruption.
832 */
833 typedef struct sqlite3_io_methods sqlite3_io_methods;
834 struct sqlite3_io_methods {
835   int iVersion;
836   int (*xClose)(sqlite3_file*);
837   int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
838   int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
839   int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
840   int (*xSync)(sqlite3_file*, int flags);
841   int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
842   int (*xLock)(sqlite3_file*, int);
843   int (*xUnlock)(sqlite3_file*, int);
844   int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
845   int (*xFileControl)(sqlite3_file*, int op, void *pArg);
846   int (*xSectorSize)(sqlite3_file*);
847   int (*xDeviceCharacteristics)(sqlite3_file*);
848   /* Methods above are valid for version 1 */
849   int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
850   int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
851   void (*xShmBarrier)(sqlite3_file*);
852   int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
853   /* Methods above are valid for version 2 */
854   int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
855   int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
856   /* Methods above are valid for version 3 */
857   /* Additional methods may be added in future releases */
858 };
859 
860 /*
861 ** CAPI3REF: Standard File Control Opcodes
862 ** KEYWORDS: {file control opcodes} {file control opcode}
863 **
864 ** These integer constants are opcodes for the xFileControl method
865 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
866 ** interface.
867 **
868 ** <ul>
869 ** <li>[[SQLITE_FCNTL_LOCKSTATE]]
870 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
871 ** opcode causes the xFileControl method to write the current state of
872 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
873 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
874 ** into an integer that the pArg argument points to.
875 ** This capability is only available if SQLite is compiled with [SQLITE_DEBUG].
876 **
877 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
878 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
879 ** layer a hint of how large the database file will grow to be during the
880 ** current transaction.  This hint is not guaranteed to be accurate but it
881 ** is often close.  The underlying VFS might choose to preallocate database
882 ** file space based on this hint in order to help writes to the database
883 ** file run faster.
884 **
885 ** <li>[[SQLITE_FCNTL_SIZE_LIMIT]]
886 ** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that
887 ** implements [sqlite3_deserialize()] to set an upper bound on the size
888 ** of the in-memory database.  The argument is a pointer to a [sqlite3_int64].
889 ** If the integer pointed to is negative, then it is filled in with the
890 ** current limit.  Otherwise the limit is set to the larger of the value
891 ** of the integer pointed to and the current database size.  The integer
892 ** pointed to is set to the new limit.
893 **
894 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
895 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
896 ** extends and truncates the database file in chunks of a size specified
897 ** by the user. The fourth argument to [sqlite3_file_control()] should
898 ** point to an integer (type int) containing the new chunk-size to use
899 ** for the nominated database. Allocating database file space in large
900 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
901 ** improve performance on some systems.
902 **
903 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
904 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
905 ** to the [sqlite3_file] object associated with a particular database
906 ** connection.  See also [SQLITE_FCNTL_JOURNAL_POINTER].
907 **
908 ** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
909 ** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
910 ** to the [sqlite3_file] object associated with the journal file (either
911 ** the [rollback journal] or the [write-ahead log]) for a particular database
912 ** connection.  See also [SQLITE_FCNTL_FILE_POINTER].
913 **
914 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
915 ** No longer in use.
916 **
917 ** <li>[[SQLITE_FCNTL_SYNC]]
918 ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
919 ** sent to the VFS immediately before the xSync method is invoked on a
920 ** database file descriptor. Or, if the xSync method is not invoked
921 ** because the user has configured SQLite with
922 ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
923 ** of the xSync method. In most cases, the pointer argument passed with
924 ** this file-control is NULL. However, if the database file is being synced
925 ** as part of a multi-database commit, the argument points to a nul-terminated
926 ** string containing the transactions super-journal file name. VFSes that
927 ** do not need this signal should silently ignore this opcode. Applications
928 ** should not call [sqlite3_file_control()] with this opcode as doing so may
929 ** disrupt the operation of the specialized VFSes that do require it.
930 **
931 ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
932 ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
933 ** and sent to the VFS after a transaction has been committed immediately
934 ** but before the database is unlocked. VFSes that do not need this signal
935 ** should silently ignore this opcode. Applications should not call
936 ** [sqlite3_file_control()] with this opcode as doing so may disrupt the
937 ** operation of the specialized VFSes that do require it.
938 **
939 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
940 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
941 ** retry counts and intervals for certain disk I/O operations for the
942 ** windows [VFS] in order to provide robustness in the presence of
943 ** anti-virus programs.  By default, the windows VFS will retry file read,
944 ** file write, and file delete operations up to 10 times, with a delay
945 ** of 25 milliseconds before the first retry and with the delay increasing
946 ** by an additional 25 milliseconds with each subsequent retry.  This
947 ** opcode allows these two values (10 retries and 25 milliseconds of delay)
948 ** to be adjusted.  The values are changed for all database connections
949 ** within the same process.  The argument is a pointer to an array of two
950 ** integers where the first integer is the new retry count and the second
951 ** integer is the delay.  If either integer is negative, then the setting
952 ** is not changed but instead the prior value of that setting is written
953 ** into the array entry, allowing the current retry settings to be
954 ** interrogated.  The zDbName parameter is ignored.
955 **
956 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
957 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
958 ** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
959 ** write ahead log ([WAL file]) and shared memory
960 ** files used for transaction control
961 ** are automatically deleted when the latest connection to the database
962 ** closes.  Setting persistent WAL mode causes those files to persist after
963 ** close.  Persisting the files is useful when other processes that do not
964 ** have write permission on the directory containing the database file want
965 ** to read the database file, as the WAL and shared memory files must exist
966 ** in order for the database to be readable.  The fourth parameter to
967 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
968 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
969 ** WAL mode.  If the integer is -1, then it is overwritten with the current
970 ** WAL persistence setting.
971 **
972 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
973 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
974 ** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
975 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
976 ** xDeviceCharacteristics methods. The fourth parameter to
977 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
978 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
979 ** mode.  If the integer is -1, then it is overwritten with the current
980 ** zero-damage mode setting.
981 **
982 ** <li>[[SQLITE_FCNTL_OVERWRITE]]
983 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
984 ** a write transaction to indicate that, unless it is rolled back for some
985 ** reason, the entire database file will be overwritten by the current
986 ** transaction. This is used by VACUUM operations.
987 **
988 ** <li>[[SQLITE_FCNTL_VFSNAME]]
989 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
990 ** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
991 ** final bottom-level VFS are written into memory obtained from
992 ** [sqlite3_malloc()] and the result is stored in the char* variable
993 ** that the fourth parameter of [sqlite3_file_control()] points to.
994 ** The caller is responsible for freeing the memory when done.  As with
995 ** all file-control actions, there is no guarantee that this will actually
996 ** do anything.  Callers should initialize the char* variable to a NULL
997 ** pointer in case this file-control is not implemented.  This file-control
998 ** is intended for diagnostic use only.
999 **
1000 ** <li>[[SQLITE_FCNTL_VFS_POINTER]]
1001 ** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
1002 ** [VFSes] currently in use.  ^(The argument X in
1003 ** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
1004 ** of type "[sqlite3_vfs] **".  This opcodes will set *X
1005 ** to a pointer to the top-level VFS.)^
1006 ** ^When there are multiple VFS shims in the stack, this opcode finds the
1007 ** upper-most shim only.
1008 **
1009 ** <li>[[SQLITE_FCNTL_PRAGMA]]
1010 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
1011 ** file control is sent to the open [sqlite3_file] object corresponding
1012 ** to the database file to which the pragma statement refers. ^The argument
1013 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
1014 ** pointers to strings (char**) in which the second element of the array
1015 ** is the name of the pragma and the third element is the argument to the
1016 ** pragma or NULL if the pragma has no argument.  ^The handler for an
1017 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
1018 ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
1019 ** or the equivalent and that string will become the result of the pragma or
1020 ** the error message if the pragma fails. ^If the
1021 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
1022 ** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
1023 ** file control returns [SQLITE_OK], then the parser assumes that the
1024 ** VFS has handled the PRAGMA itself and the parser generates a no-op
1025 ** prepared statement if result string is NULL, or that returns a copy
1026 ** of the result string if the string is non-NULL.
1027 ** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
1028 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
1029 ** that the VFS encountered an error while handling the [PRAGMA] and the
1030 ** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
1031 ** file control occurs at the beginning of pragma statement analysis and so
1032 ** it is able to override built-in [PRAGMA] statements.
1033 **
1034 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
1035 ** ^The [SQLITE_FCNTL_BUSYHANDLER]
1036 ** file-control may be invoked by SQLite on the database file handle
1037 ** shortly after it is opened in order to provide a custom VFS with access
1038 ** to the connection's busy-handler callback. The argument is of type (void**)
1039 ** - an array of two (void *) values. The first (void *) actually points
1040 ** to a function of type (int (*)(void *)). In order to invoke the connection's
1041 ** busy-handler, this function should be invoked with the second (void *) in
1042 ** the array as the only argument. If it returns non-zero, then the operation
1043 ** should be retried. If it returns zero, the custom VFS should abandon the
1044 ** current operation.
1045 **
1046 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
1047 ** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
1048 ** to have SQLite generate a
1049 ** temporary filename using the same algorithm that is followed to generate
1050 ** temporary filenames for TEMP tables and other internal uses.  The
1051 ** argument should be a char** which will be filled with the filename
1052 ** written into memory obtained from [sqlite3_malloc()].  The caller should
1053 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
1054 **
1055 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
1056 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
1057 ** maximum number of bytes that will be used for memory-mapped I/O.
1058 ** The argument is a pointer to a value of type sqlite3_int64 that
1059 ** is an advisory maximum number of bytes in the file to memory map.  The
1060 ** pointer is overwritten with the old value.  The limit is not changed if
1061 ** the value originally pointed to is negative, and so the current limit
1062 ** can be queried by passing in a pointer to a negative number.  This
1063 ** file-control is used internally to implement [PRAGMA mmap_size].
1064 **
1065 ** <li>[[SQLITE_FCNTL_TRACE]]
1066 ** The [SQLITE_FCNTL_TRACE] file control provides advisory information
1067 ** to the VFS about what the higher layers of the SQLite stack are doing.
1068 ** This file control is used by some VFS activity tracing [shims].
1069 ** The argument is a zero-terminated string.  Higher layers in the
1070 ** SQLite stack may generate instances of this file control if
1071 ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
1072 **
1073 ** <li>[[SQLITE_FCNTL_HAS_MOVED]]
1074 ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
1075 ** pointer to an integer and it writes a boolean into that integer depending
1076 ** on whether or not the file has been renamed, moved, or deleted since it
1077 ** was first opened.
1078 **
1079 ** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
1080 ** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
1081 ** underlying native file handle associated with a file handle.  This file
1082 ** control interprets its argument as a pointer to a native file handle and
1083 ** writes the resulting value there.
1084 **
1085 ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
1086 ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
1087 ** opcode causes the xFileControl method to swap the file handle with the one
1088 ** pointed to by the pArg argument.  This capability is used during testing
1089 ** and only needs to be supported when SQLITE_TEST is defined.
1090 **
1091 ** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
1092 ** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
1093 ** be advantageous to block on the next WAL lock if the lock is not immediately
1094 ** available.  The WAL subsystem issues this signal during rare
1095 ** circumstances in order to fix a problem with priority inversion.
1096 ** Applications should <em>not</em> use this file-control.
1097 **
1098 ** <li>[[SQLITE_FCNTL_ZIPVFS]]
1099 ** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
1100 ** VFS should return SQLITE_NOTFOUND for this opcode.
1101 **
1102 ** <li>[[SQLITE_FCNTL_RBU]]
1103 ** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
1104 ** the RBU extension only.  All other VFS should return SQLITE_NOTFOUND for
1105 ** this opcode.
1106 **
1107 ** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
1108 ** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
1109 ** the file descriptor is placed in "batch write mode", which
1110 ** means all subsequent write operations will be deferred and done
1111 ** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].  Systems
1112 ** that do not support batch atomic writes will return SQLITE_NOTFOUND.
1113 ** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
1114 ** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
1115 ** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
1116 ** no VFS interface calls on the same [sqlite3_file] file descriptor
1117 ** except for calls to the xWrite method and the xFileControl method
1118 ** with [SQLITE_FCNTL_SIZE_HINT].
1119 **
1120 ** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
1121 ** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
1122 ** operations since the previous successful call to
1123 ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
1124 ** This file control returns [SQLITE_OK] if and only if the writes were
1125 ** all performed successfully and have been committed to persistent storage.
1126 ** ^Regardless of whether or not it is successful, this file control takes
1127 ** the file descriptor out of batch write mode so that all subsequent
1128 ** write operations are independent.
1129 ** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
1130 ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1131 **
1132 ** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
1133 ** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
1134 ** operations since the previous successful call to
1135 ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
1136 ** ^This file control takes the file descriptor out of batch write mode
1137 ** so that all subsequent write operations are independent.
1138 ** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
1139 ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1140 **
1141 ** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]]
1142 ** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS
1143 ** to block for up to M milliseconds before failing when attempting to
1144 ** obtain a file lock using the xLock or xShmLock methods of the VFS.
1145 ** The parameter is a pointer to a 32-bit signed integer that contains
1146 ** the value that M is to be set to. Before returning, the 32-bit signed
1147 ** integer is overwritten with the previous value of M.
1148 **
1149 ** <li>[[SQLITE_FCNTL_DATA_VERSION]]
1150 ** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
1151 ** a database file.  The argument is a pointer to a 32-bit unsigned integer.
1152 ** The "data version" for the pager is written into the pointer.  The
1153 ** "data version" changes whenever any change occurs to the corresponding
1154 ** database file, either through SQL statements on the same database
1155 ** connection or through transactions committed by separate database
1156 ** connections possibly in other processes. The [sqlite3_total_changes()]
1157 ** interface can be used to find if any database on the connection has changed,
1158 ** but that interface responds to changes on TEMP as well as MAIN and does
1159 ** not provide a mechanism to detect changes to MAIN only.  Also, the
1160 ** [sqlite3_total_changes()] interface responds to internal changes only and
1161 ** omits changes made by other database connections.  The
1162 ** [PRAGMA data_version] command provides a mechanism to detect changes to
1163 ** a single attached database that occur due to other database connections,
1164 ** but omits changes implemented by the database connection on which it is
1165 ** called.  This file control is the only mechanism to detect changes that
1166 ** happen either internally or externally and that are associated with
1167 ** a particular attached database.
1168 **
1169 ** <li>[[SQLITE_FCNTL_CKPT_START]]
1170 ** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint
1171 ** in wal mode before the client starts to copy pages from the wal
1172 ** file to the database file.
1173 **
1174 ** <li>[[SQLITE_FCNTL_CKPT_DONE]]
1175 ** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint
1176 ** in wal mode after the client has finished copying pages from the wal
1177 ** file to the database file, but before the *-shm file is updated to
1178 ** record the fact that the pages have been checkpointed.
1179 **
1180 ** <li>[[SQLITE_FCNTL_EXTERNAL_READER]]
1181 ** The EXPERIMENTAL [SQLITE_FCNTL_EXTERNAL_READER] opcode is used to detect
1182 ** whether or not there is a database client in another process with a wal-mode
1183 ** transaction open on the database or not. It is only available on unix.The
1184 ** (void*) argument passed with this file-control should be a pointer to a
1185 ** value of type (int). The integer value is set to 1 if the database is a wal
1186 ** mode database and there exists at least one client in another process that
1187 ** currently has an SQL transaction open on the database. It is set to 0 if
1188 ** the database is not a wal-mode db, or if there is no such connection in any
1189 ** other process. This opcode cannot be used to detect transactions opened
1190 ** by clients within the current process, only within other processes.
1191 **
1192 ** <li>[[SQLITE_FCNTL_CKSM_FILE]]
1193 ** The [SQLITE_FCNTL_CKSM_FILE] opcode is for use interally by the
1194 ** [checksum VFS shim] only.
1195 **
1196 ** <li>[[SQLITE_FCNTL_RESET_CACHE]]
1197 ** If there is currently no transaction open on the database, and the
1198 ** database is not a temp db, then the [SQLITE_FCNTL_RESET_CACHE] file-control
1199 ** purges the contents of the in-memory page cache. If there is an open
1200 ** transaction, or if the db is a temp-db, this opcode is a no-op, not an error.
1201 ** </ul>
1202 */
1203 #define SQLITE_FCNTL_LOCKSTATE               1
1204 #define SQLITE_FCNTL_GET_LOCKPROXYFILE       2
1205 #define SQLITE_FCNTL_SET_LOCKPROXYFILE       3
1206 #define SQLITE_FCNTL_LAST_ERRNO              4
1207 #define SQLITE_FCNTL_SIZE_HINT               5
1208 #define SQLITE_FCNTL_CHUNK_SIZE              6
1209 #define SQLITE_FCNTL_FILE_POINTER            7
1210 #define SQLITE_FCNTL_SYNC_OMITTED            8
1211 #define SQLITE_FCNTL_WIN32_AV_RETRY          9
1212 #define SQLITE_FCNTL_PERSIST_WAL            10
1213 #define SQLITE_FCNTL_OVERWRITE              11
1214 #define SQLITE_FCNTL_VFSNAME                12
1215 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
1216 #define SQLITE_FCNTL_PRAGMA                 14
1217 #define SQLITE_FCNTL_BUSYHANDLER            15
1218 #define SQLITE_FCNTL_TEMPFILENAME           16
1219 #define SQLITE_FCNTL_MMAP_SIZE              18
1220 #define SQLITE_FCNTL_TRACE                  19
1221 #define SQLITE_FCNTL_HAS_MOVED              20
1222 #define SQLITE_FCNTL_SYNC                   21
1223 #define SQLITE_FCNTL_COMMIT_PHASETWO        22
1224 #define SQLITE_FCNTL_WIN32_SET_HANDLE       23
1225 #define SQLITE_FCNTL_WAL_BLOCK              24
1226 #define SQLITE_FCNTL_ZIPVFS                 25
1227 #define SQLITE_FCNTL_RBU                    26
1228 #define SQLITE_FCNTL_VFS_POINTER            27
1229 #define SQLITE_FCNTL_JOURNAL_POINTER        28
1230 #define SQLITE_FCNTL_WIN32_GET_HANDLE       29
1231 #define SQLITE_FCNTL_PDB                    30
1232 #define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE     31
1233 #define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE    32
1234 #define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE  33
1235 #define SQLITE_FCNTL_LOCK_TIMEOUT           34
1236 #define SQLITE_FCNTL_DATA_VERSION           35
1237 #define SQLITE_FCNTL_SIZE_LIMIT             36
1238 #define SQLITE_FCNTL_CKPT_DONE              37
1239 #define SQLITE_FCNTL_RESERVE_BYTES          38
1240 #define SQLITE_FCNTL_CKPT_START             39
1241 #define SQLITE_FCNTL_EXTERNAL_READER        40
1242 #define SQLITE_FCNTL_CKSM_FILE              41
1243 #define SQLITE_FCNTL_RESET_CACHE            42
1244 
1245 /* deprecated names */
1246 #define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
1247 #define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
1248 #define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO
1249 
1250 
1251 /*
1252 ** CAPI3REF: Mutex Handle
1253 **
1254 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
1255 ** abstract type for a mutex object.  The SQLite core never looks
1256 ** at the internal representation of an [sqlite3_mutex].  It only
1257 ** deals with pointers to the [sqlite3_mutex] object.
1258 **
1259 ** Mutexes are created using [sqlite3_mutex_alloc()].
1260 */
1261 typedef struct sqlite3_mutex sqlite3_mutex;
1262 
1263 /*
1264 ** CAPI3REF: Loadable Extension Thunk
1265 **
1266 ** A pointer to the opaque sqlite3_api_routines structure is passed as
1267 ** the third parameter to entry points of [loadable extensions].  This
1268 ** structure must be typedefed in order to work around compiler warnings
1269 ** on some platforms.
1270 */
1271 typedef struct sqlite3_api_routines sqlite3_api_routines;
1272 
1273 /*
1274 ** CAPI3REF: File Name
1275 **
1276 ** Type [sqlite3_filename] is used by SQLite to pass filenames to the
1277 ** xOpen method of a [VFS]. It may be cast to (const char*) and treated
1278 ** as a normal, nul-terminated, UTF-8 buffer containing the filename, but
1279 ** may also be passed to special APIs such as:
1280 **
1281 ** <ul>
1282 ** <li>  sqlite3_filename_database()
1283 ** <li>  sqlite3_filename_journal()
1284 ** <li>  sqlite3_filename_wal()
1285 ** <li>  sqlite3_uri_parameter()
1286 ** <li>  sqlite3_uri_boolean()
1287 ** <li>  sqlite3_uri_int64()
1288 ** <li>  sqlite3_uri_key()
1289 ** </ul>
1290 */
1291 typedef const char *sqlite3_filename;
1292 
1293 /*
1294 ** CAPI3REF: OS Interface Object
1295 **
1296 ** An instance of the sqlite3_vfs object defines the interface between
1297 ** the SQLite core and the underlying operating system.  The "vfs"
1298 ** in the name of the object stands for "virtual file system".  See
1299 ** the [VFS | VFS documentation] for further information.
1300 **
1301 ** The VFS interface is sometimes extended by adding new methods onto
1302 ** the end.  Each time such an extension occurs, the iVersion field
1303 ** is incremented.  The iVersion value started out as 1 in
1304 ** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
1305 ** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
1306 ** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6].  Additional fields
1307 ** may be appended to the sqlite3_vfs object and the iVersion value
1308 ** may increase again in future versions of SQLite.
1309 ** Note that due to an oversight, the structure
1310 ** of the sqlite3_vfs object changed in the transition from
1311 ** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
1312 ** and yet the iVersion field was not increased.
1313 **
1314 ** The szOsFile field is the size of the subclassed [sqlite3_file]
1315 ** structure used by this VFS.  mxPathname is the maximum length of
1316 ** a pathname in this VFS.
1317 **
1318 ** Registered sqlite3_vfs objects are kept on a linked list formed by
1319 ** the pNext pointer.  The [sqlite3_vfs_register()]
1320 ** and [sqlite3_vfs_unregister()] interfaces manage this list
1321 ** in a thread-safe way.  The [sqlite3_vfs_find()] interface
1322 ** searches the list.  Neither the application code nor the VFS
1323 ** implementation should use the pNext pointer.
1324 **
1325 ** The pNext field is the only field in the sqlite3_vfs
1326 ** structure that SQLite will ever modify.  SQLite will only access
1327 ** or modify this field while holding a particular static mutex.
1328 ** The application should never modify anything within the sqlite3_vfs
1329 ** object once the object has been registered.
1330 **
1331 ** The zName field holds the name of the VFS module.  The name must
1332 ** be unique across all VFS modules.
1333 **
1334 ** [[sqlite3_vfs.xOpen]]
1335 ** ^SQLite guarantees that the zFilename parameter to xOpen
1336 ** is either a NULL pointer or string obtained
1337 ** from xFullPathname() with an optional suffix added.
1338 ** ^If a suffix is added to the zFilename parameter, it will
1339 ** consist of a single "-" character followed by no more than
1340 ** 11 alphanumeric and/or "-" characters.
1341 ** ^SQLite further guarantees that
1342 ** the string will be valid and unchanged until xClose() is
1343 ** called. Because of the previous sentence,
1344 ** the [sqlite3_file] can safely store a pointer to the
1345 ** filename if it needs to remember the filename for some reason.
1346 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1347 ** must invent its own temporary name for the file.  ^Whenever the
1348 ** xFilename parameter is NULL it will also be the case that the
1349 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1350 **
1351 ** The flags argument to xOpen() includes all bits set in
1352 ** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
1353 ** or [sqlite3_open16()] is used, then flags includes at least
1354 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1355 ** If xOpen() opens a file read-only then it sets *pOutFlags to
1356 ** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
1357 **
1358 ** ^(SQLite will also add one of the following flags to the xOpen()
1359 ** call, depending on the object being opened:
1360 **
1361 ** <ul>
1362 ** <li>  [SQLITE_OPEN_MAIN_DB]
1363 ** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
1364 ** <li>  [SQLITE_OPEN_TEMP_DB]
1365 ** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
1366 ** <li>  [SQLITE_OPEN_TRANSIENT_DB]
1367 ** <li>  [SQLITE_OPEN_SUBJOURNAL]
1368 ** <li>  [SQLITE_OPEN_SUPER_JOURNAL]
1369 ** <li>  [SQLITE_OPEN_WAL]
1370 ** </ul>)^
1371 **
1372 ** The file I/O implementation can use the object type flags to
1373 ** change the way it deals with files.  For example, an application
1374 ** that does not care about crash recovery or rollback might make
1375 ** the open of a journal file a no-op.  Writes to this journal would
1376 ** also be no-ops, and any attempt to read the journal would return
1377 ** SQLITE_IOERR.  Or the implementation might recognize that a database
1378 ** file will be doing page-aligned sector reads and writes in a random
1379 ** order and set up its I/O subsystem accordingly.
1380 **
1381 ** SQLite might also add one of the following flags to the xOpen method:
1382 **
1383 ** <ul>
1384 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
1385 ** <li> [SQLITE_OPEN_EXCLUSIVE]
1386 ** </ul>
1387 **
1388 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1389 ** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
1390 ** will be set for TEMP databases and their journals, transient
1391 ** databases, and subjournals.
1392 **
1393 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1394 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1395 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1396 ** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1397 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1398 ** be created, and that it is an error if it already exists.
1399 ** It is <i>not</i> used to indicate the file should be opened
1400 ** for exclusive access.
1401 **
1402 ** ^At least szOsFile bytes of memory are allocated by SQLite
1403 ** to hold the [sqlite3_file] structure passed as the third
1404 ** argument to xOpen.  The xOpen method does not have to
1405 ** allocate the structure; it should just fill it in.  Note that
1406 ** the xOpen method must set the sqlite3_file.pMethods to either
1407 ** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
1408 ** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
1409 ** element will be valid after xOpen returns regardless of the success
1410 ** or failure of the xOpen call.
1411 **
1412 ** [[sqlite3_vfs.xAccess]]
1413 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1414 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1415 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1416 ** to test whether a file is at least readable.  The SQLITE_ACCESS_READ
1417 ** flag is never actually used and is not implemented in the built-in
1418 ** VFSes of SQLite.  The file is named by the second argument and can be a
1419 ** directory. The xAccess method returns [SQLITE_OK] on success or some
1420 ** non-zero error code if there is an I/O error or if the name of
1421 ** the file given in the second argument is illegal.  If SQLITE_OK
1422 ** is returned, then non-zero or zero is written into *pResOut to indicate
1423 ** whether or not the file is accessible.
1424 **
1425 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1426 ** output buffer xFullPathname.  The exact size of the output buffer
1427 ** is also passed as a parameter to both  methods. If the output buffer
1428 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1429 ** handled as a fatal error by SQLite, vfs implementations should endeavor
1430 ** to prevent this by setting mxPathname to a sufficiently large value.
1431 **
1432 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1433 ** interfaces are not strictly a part of the filesystem, but they are
1434 ** included in the VFS structure for completeness.
1435 ** The xRandomness() function attempts to return nBytes bytes
1436 ** of good-quality randomness into zOut.  The return value is
1437 ** the actual number of bytes of randomness obtained.
1438 ** The xSleep() method causes the calling thread to sleep for at
1439 ** least the number of microseconds given.  ^The xCurrentTime()
1440 ** method returns a Julian Day Number for the current date and time as
1441 ** a floating point value.
1442 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1443 ** Day Number multiplied by 86400000 (the number of milliseconds in
1444 ** a 24-hour day).
1445 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1446 ** date and time if that method is available (if iVersion is 2 or
1447 ** greater and the function pointer is not NULL) and will fall back
1448 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1449 **
1450 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1451 ** are not used by the SQLite core.  These optional interfaces are provided
1452 ** by some VFSes to facilitate testing of the VFS code. By overriding
1453 ** system calls with functions under its control, a test program can
1454 ** simulate faults and error conditions that would otherwise be difficult
1455 ** or impossible to induce.  The set of system calls that can be overridden
1456 ** varies from one VFS to another, and from one version of the same VFS to the
1457 ** next.  Applications that use these interfaces must be prepared for any
1458 ** or all of these interfaces to be NULL or for their behavior to change
1459 ** from one release to the next.  Applications must not attempt to access
1460 ** any of these methods if the iVersion of the VFS is less than 3.
1461 */
1462 typedef struct sqlite3_vfs sqlite3_vfs;
1463 typedef void (*sqlite3_syscall_ptr)(void);
1464 struct sqlite3_vfs {
1465   int iVersion;            /* Structure version number (currently 3) */
1466   int szOsFile;            /* Size of subclassed sqlite3_file */
1467   int mxPathname;          /* Maximum file pathname length */
1468   sqlite3_vfs *pNext;      /* Next registered VFS */
1469   const char *zName;       /* Name of this virtual file system */
1470   void *pAppData;          /* Pointer to application-specific data */
1471   int (*xOpen)(sqlite3_vfs*, sqlite3_filename zName, sqlite3_file*,
1472                int flags, int *pOutFlags);
1473   int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1474   int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1475   int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1476   void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1477   void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1478   void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1479   void (*xDlClose)(sqlite3_vfs*, void*);
1480   int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1481   int (*xSleep)(sqlite3_vfs*, int microseconds);
1482   int (*xCurrentTime)(sqlite3_vfs*, double*);
1483   int (*xGetLastError)(sqlite3_vfs*, int, char *);
1484   /*
1485   ** The methods above are in version 1 of the sqlite_vfs object
1486   ** definition.  Those that follow are added in version 2 or later
1487   */
1488   int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1489   /*
1490   ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1491   ** Those below are for version 3 and greater.
1492   */
1493   int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1494   sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1495   const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1496   /*
1497   ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1498   ** New fields may be appended in future versions.  The iVersion
1499   ** value will increment whenever this happens.
1500   */
1501 };
1502 
1503 /*
1504 ** CAPI3REF: Flags for the xAccess VFS method
1505 **
1506 ** These integer constants can be used as the third parameter to
1507 ** the xAccess method of an [sqlite3_vfs] object.  They determine
1508 ** what kind of permissions the xAccess method is looking for.
1509 ** With SQLITE_ACCESS_EXISTS, the xAccess method
1510 ** simply checks whether the file exists.
1511 ** With SQLITE_ACCESS_READWRITE, the xAccess method
1512 ** checks whether the named directory is both readable and writable
1513 ** (in other words, if files can be added, removed, and renamed within
1514 ** the directory).
1515 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1516 ** [temp_store_directory pragma], though this could change in a future
1517 ** release of SQLite.
1518 ** With SQLITE_ACCESS_READ, the xAccess method
1519 ** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
1520 ** currently unused, though it might be used in a future release of
1521 ** SQLite.
1522 */
1523 #define SQLITE_ACCESS_EXISTS    0
1524 #define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
1525 #define SQLITE_ACCESS_READ      2   /* Unused */
1526 
1527 /*
1528 ** CAPI3REF: Flags for the xShmLock VFS method
1529 **
1530 ** These integer constants define the various locking operations
1531 ** allowed by the xShmLock method of [sqlite3_io_methods].  The
1532 ** following are the only legal combinations of flags to the
1533 ** xShmLock method:
1534 **
1535 ** <ul>
1536 ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1537 ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1538 ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1539 ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1540 ** </ul>
1541 **
1542 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1543 ** was given on the corresponding lock.
1544 **
1545 ** The xShmLock method can transition between unlocked and SHARED or
1546 ** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
1547 ** and EXCLUSIVE.
1548 */
1549 #define SQLITE_SHM_UNLOCK       1
1550 #define SQLITE_SHM_LOCK         2
1551 #define SQLITE_SHM_SHARED       4
1552 #define SQLITE_SHM_EXCLUSIVE    8
1553 
1554 /*
1555 ** CAPI3REF: Maximum xShmLock index
1556 **
1557 ** The xShmLock method on [sqlite3_io_methods] may use values
1558 ** between 0 and this upper bound as its "offset" argument.
1559 ** The SQLite core will never attempt to acquire or release a
1560 ** lock outside of this range
1561 */
1562 #define SQLITE_SHM_NLOCK        8
1563 
1564 
1565 /*
1566 ** CAPI3REF: Initialize The SQLite Library
1567 **
1568 ** ^The sqlite3_initialize() routine initializes the
1569 ** SQLite library.  ^The sqlite3_shutdown() routine
1570 ** deallocates any resources that were allocated by sqlite3_initialize().
1571 ** These routines are designed to aid in process initialization and
1572 ** shutdown on embedded systems.  Workstation applications using
1573 ** SQLite normally do not need to invoke either of these routines.
1574 **
1575 ** A call to sqlite3_initialize() is an "effective" call if it is
1576 ** the first time sqlite3_initialize() is invoked during the lifetime of
1577 ** the process, or if it is the first time sqlite3_initialize() is invoked
1578 ** following a call to sqlite3_shutdown().  ^(Only an effective call
1579 ** of sqlite3_initialize() does any initialization.  All other calls
1580 ** are harmless no-ops.)^
1581 **
1582 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1583 ** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
1584 ** an effective call to sqlite3_shutdown() does any deinitialization.
1585 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1586 **
1587 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1588 ** is not.  The sqlite3_shutdown() interface must only be called from a
1589 ** single thread.  All open [database connections] must be closed and all
1590 ** other SQLite resources must be deallocated prior to invoking
1591 ** sqlite3_shutdown().
1592 **
1593 ** Among other things, ^sqlite3_initialize() will invoke
1594 ** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
1595 ** will invoke sqlite3_os_end().
1596 **
1597 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1598 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1599 ** the library (perhaps it is unable to allocate a needed resource such
1600 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1601 **
1602 ** ^The sqlite3_initialize() routine is called internally by many other
1603 ** SQLite interfaces so that an application usually does not need to
1604 ** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
1605 ** calls sqlite3_initialize() so the SQLite library will be automatically
1606 ** initialized when [sqlite3_open()] is called if it has not be initialized
1607 ** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1608 ** compile-time option, then the automatic calls to sqlite3_initialize()
1609 ** are omitted and the application must call sqlite3_initialize() directly
1610 ** prior to using any other SQLite interface.  For maximum portability,
1611 ** it is recommended that applications always invoke sqlite3_initialize()
1612 ** directly prior to using any other SQLite interface.  Future releases
1613 ** of SQLite may require this.  In other words, the behavior exhibited
1614 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1615 ** default behavior in some future release of SQLite.
1616 **
1617 ** The sqlite3_os_init() routine does operating-system specific
1618 ** initialization of the SQLite library.  The sqlite3_os_end()
1619 ** routine undoes the effect of sqlite3_os_init().  Typical tasks
1620 ** performed by these routines include allocation or deallocation
1621 ** of static resources, initialization of global variables,
1622 ** setting up a default [sqlite3_vfs] module, or setting up
1623 ** a default configuration using [sqlite3_config()].
1624 **
1625 ** The application should never invoke either sqlite3_os_init()
1626 ** or sqlite3_os_end() directly.  The application should only invoke
1627 ** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
1628 ** interface is called automatically by sqlite3_initialize() and
1629 ** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
1630 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1631 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1632 ** When [custom builds | built for other platforms]
1633 ** (using the [SQLITE_OS_OTHER=1] compile-time
1634 ** option) the application must supply a suitable implementation for
1635 ** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
1636 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1637 ** must return [SQLITE_OK] on success and some other [error code] upon
1638 ** failure.
1639 */
1640 SQLITE_API int sqlite3_initialize(void);
1641 SQLITE_API int sqlite3_shutdown(void);
1642 SQLITE_API int sqlite3_os_init(void);
1643 SQLITE_API int sqlite3_os_end(void);
1644 
1645 /*
1646 ** CAPI3REF: Configuring The SQLite Library
1647 **
1648 ** The sqlite3_config() interface is used to make global configuration
1649 ** changes to SQLite in order to tune SQLite to the specific needs of
1650 ** the application.  The default configuration is recommended for most
1651 ** applications and so this routine is usually not necessary.  It is
1652 ** provided to support rare applications with unusual needs.
1653 **
1654 ** <b>The sqlite3_config() interface is not threadsafe. The application
1655 ** must ensure that no other SQLite interfaces are invoked by other
1656 ** threads while sqlite3_config() is running.</b>
1657 **
1658 ** The sqlite3_config() interface
1659 ** may only be invoked prior to library initialization using
1660 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1661 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1662 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1663 ** Note, however, that ^sqlite3_config() can be called as part of the
1664 ** implementation of an application-defined [sqlite3_os_init()].
1665 **
1666 ** The first argument to sqlite3_config() is an integer
1667 ** [configuration option] that determines
1668 ** what property of SQLite is to be configured.  Subsequent arguments
1669 ** vary depending on the [configuration option]
1670 ** in the first argument.
1671 **
1672 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1673 ** ^If the option is unknown or SQLite is unable to set the option
1674 ** then this routine returns a non-zero [error code].
1675 */
1676 SQLITE_API int sqlite3_config(int, ...);
1677 
1678 /*
1679 ** CAPI3REF: Configure database connections
1680 ** METHOD: sqlite3
1681 **
1682 ** The sqlite3_db_config() interface is used to make configuration
1683 ** changes to a [database connection].  The interface is similar to
1684 ** [sqlite3_config()] except that the changes apply to a single
1685 ** [database connection] (specified in the first argument).
1686 **
1687 ** The second argument to sqlite3_db_config(D,V,...)  is the
1688 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1689 ** that indicates what aspect of the [database connection] is being configured.
1690 ** Subsequent arguments vary depending on the configuration verb.
1691 **
1692 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1693 ** the call is considered successful.
1694 */
1695 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1696 
1697 /*
1698 ** CAPI3REF: Memory Allocation Routines
1699 **
1700 ** An instance of this object defines the interface between SQLite
1701 ** and low-level memory allocation routines.
1702 **
1703 ** This object is used in only one place in the SQLite interface.
1704 ** A pointer to an instance of this object is the argument to
1705 ** [sqlite3_config()] when the configuration option is
1706 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1707 ** By creating an instance of this object
1708 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1709 ** during configuration, an application can specify an alternative
1710 ** memory allocation subsystem for SQLite to use for all of its
1711 ** dynamic memory needs.
1712 **
1713 ** Note that SQLite comes with several [built-in memory allocators]
1714 ** that are perfectly adequate for the overwhelming majority of applications
1715 ** and that this object is only useful to a tiny minority of applications
1716 ** with specialized memory allocation requirements.  This object is
1717 ** also used during testing of SQLite in order to specify an alternative
1718 ** memory allocator that simulates memory out-of-memory conditions in
1719 ** order to verify that SQLite recovers gracefully from such
1720 ** conditions.
1721 **
1722 ** The xMalloc, xRealloc, and xFree methods must work like the
1723 ** malloc(), realloc() and free() functions from the standard C library.
1724 ** ^SQLite guarantees that the second argument to
1725 ** xRealloc is always a value returned by a prior call to xRoundup.
1726 **
1727 ** xSize should return the allocated size of a memory allocation
1728 ** previously obtained from xMalloc or xRealloc.  The allocated size
1729 ** is always at least as big as the requested size but may be larger.
1730 **
1731 ** The xRoundup method returns what would be the allocated size of
1732 ** a memory allocation given a particular requested size.  Most memory
1733 ** allocators round up memory allocations at least to the next multiple
1734 ** of 8.  Some allocators round up to a larger multiple or to a power of 2.
1735 ** Every memory allocation request coming in through [sqlite3_malloc()]
1736 ** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
1737 ** that causes the corresponding memory allocation to fail.
1738 **
1739 ** The xInit method initializes the memory allocator.  For example,
1740 ** it might allocate any required mutexes or initialize internal data
1741 ** structures.  The xShutdown method is invoked (indirectly) by
1742 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1743 ** by xInit.  The pAppData pointer is used as the only parameter to
1744 ** xInit and xShutdown.
1745 **
1746 ** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes
1747 ** the xInit method, so the xInit method need not be threadsafe.  The
1748 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1749 ** not need to be threadsafe either.  For all other methods, SQLite
1750 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1751 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1752 ** it is by default) and so the methods are automatically serialized.
1753 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1754 ** methods must be threadsafe or else make their own arrangements for
1755 ** serialization.
1756 **
1757 ** SQLite will never invoke xInit() more than once without an intervening
1758 ** call to xShutdown().
1759 */
1760 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1761 struct sqlite3_mem_methods {
1762   void *(*xMalloc)(int);         /* Memory allocation function */
1763   void (*xFree)(void*);          /* Free a prior allocation */
1764   void *(*xRealloc)(void*,int);  /* Resize an allocation */
1765   int (*xSize)(void*);           /* Return the size of an allocation */
1766   int (*xRoundup)(int);          /* Round up request size to allocation size */
1767   int (*xInit)(void*);           /* Initialize the memory allocator */
1768   void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
1769   void *pAppData;                /* Argument to xInit() and xShutdown() */
1770 };
1771 
1772 /*
1773 ** CAPI3REF: Configuration Options
1774 ** KEYWORDS: {configuration option}
1775 **
1776 ** These constants are the available integer configuration options that
1777 ** can be passed as the first argument to the [sqlite3_config()] interface.
1778 **
1779 ** New configuration options may be added in future releases of SQLite.
1780 ** Existing configuration options might be discontinued.  Applications
1781 ** should check the return code from [sqlite3_config()] to make sure that
1782 ** the call worked.  The [sqlite3_config()] interface will return a
1783 ** non-zero [error code] if a discontinued or unsupported configuration option
1784 ** is invoked.
1785 **
1786 ** <dl>
1787 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1788 ** <dd>There are no arguments to this option.  ^This option sets the
1789 ** [threading mode] to Single-thread.  In other words, it disables
1790 ** all mutexing and puts SQLite into a mode where it can only be used
1791 ** by a single thread.   ^If SQLite is compiled with
1792 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1793 ** it is not possible to change the [threading mode] from its default
1794 ** value of Single-thread and so [sqlite3_config()] will return
1795 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1796 ** configuration option.</dd>
1797 **
1798 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1799 ** <dd>There are no arguments to this option.  ^This option sets the
1800 ** [threading mode] to Multi-thread.  In other words, it disables
1801 ** mutexing on [database connection] and [prepared statement] objects.
1802 ** The application is responsible for serializing access to
1803 ** [database connections] and [prepared statements].  But other mutexes
1804 ** are enabled so that SQLite will be safe to use in a multi-threaded
1805 ** environment as long as no two threads attempt to use the same
1806 ** [database connection] at the same time.  ^If SQLite is compiled with
1807 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1808 ** it is not possible to set the Multi-thread [threading mode] and
1809 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1810 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1811 **
1812 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1813 ** <dd>There are no arguments to this option.  ^This option sets the
1814 ** [threading mode] to Serialized. In other words, this option enables
1815 ** all mutexes including the recursive
1816 ** mutexes on [database connection] and [prepared statement] objects.
1817 ** In this mode (which is the default when SQLite is compiled with
1818 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1819 ** to [database connections] and [prepared statements] so that the
1820 ** application is free to use the same [database connection] or the
1821 ** same [prepared statement] in different threads at the same time.
1822 ** ^If SQLite is compiled with
1823 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1824 ** it is not possible to set the Serialized [threading mode] and
1825 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1826 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1827 **
1828 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1829 ** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1830 ** a pointer to an instance of the [sqlite3_mem_methods] structure.
1831 ** The argument specifies
1832 ** alternative low-level memory allocation routines to be used in place of
1833 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1834 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1835 ** before the [sqlite3_config()] call returns.</dd>
1836 **
1837 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1838 ** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1839 ** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1840 ** The [sqlite3_mem_methods]
1841 ** structure is filled with the currently defined memory allocation routines.)^
1842 ** This option can be used to overload the default memory allocation
1843 ** routines with a wrapper that simulations memory allocation failure or
1844 ** tracks memory usage, for example. </dd>
1845 **
1846 ** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
1847 ** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
1848 ** type int, interpreted as a boolean, which if true provides a hint to
1849 ** SQLite that it should avoid large memory allocations if possible.
1850 ** SQLite will run faster if it is free to make large memory allocations,
1851 ** but some application might prefer to run slower in exchange for
1852 ** guarantees about memory fragmentation that are possible if large
1853 ** allocations are avoided.  This hint is normally off.
1854 ** </dd>
1855 **
1856 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1857 ** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1858 ** interpreted as a boolean, which enables or disables the collection of
1859 ** memory allocation statistics. ^(When memory allocation statistics are
1860 ** disabled, the following SQLite interfaces become non-operational:
1861 **   <ul>
1862 **   <li> [sqlite3_hard_heap_limit64()]
1863 **   <li> [sqlite3_memory_used()]
1864 **   <li> [sqlite3_memory_highwater()]
1865 **   <li> [sqlite3_soft_heap_limit64()]
1866 **   <li> [sqlite3_status64()]
1867 **   </ul>)^
1868 ** ^Memory allocation statistics are enabled by default unless SQLite is
1869 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1870 ** allocation statistics are disabled by default.
1871 ** </dd>
1872 **
1873 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1874 ** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
1875 ** </dd>
1876 **
1877 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1878 ** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
1879 ** that SQLite can use for the database page cache with the default page
1880 ** cache implementation.
1881 ** This configuration option is a no-op if an application-defined page
1882 ** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
1883 ** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1884 ** 8-byte aligned memory (pMem), the size of each page cache line (sz),
1885 ** and the number of cache lines (N).
1886 ** The sz argument should be the size of the largest database page
1887 ** (a power of two between 512 and 65536) plus some extra bytes for each
1888 ** page header.  ^The number of extra bytes needed by the page header
1889 ** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
1890 ** ^It is harmless, apart from the wasted memory,
1891 ** for the sz parameter to be larger than necessary.  The pMem
1892 ** argument must be either a NULL pointer or a pointer to an 8-byte
1893 ** aligned block of memory of at least sz*N bytes, otherwise
1894 ** subsequent behavior is undefined.
1895 ** ^When pMem is not NULL, SQLite will strive to use the memory provided
1896 ** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
1897 ** a page cache line is larger than sz bytes or if all of the pMem buffer
1898 ** is exhausted.
1899 ** ^If pMem is NULL and N is non-zero, then each database connection
1900 ** does an initial bulk allocation for page cache memory
1901 ** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
1902 ** of -1024*N bytes if N is negative, . ^If additional
1903 ** page cache memory is needed beyond what is provided by the initial
1904 ** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
1905 ** additional cache line. </dd>
1906 **
1907 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1908 ** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1909 ** that SQLite will use for all of its dynamic memory allocation needs
1910 ** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
1911 ** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1912 ** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1913 ** [SQLITE_ERROR] if invoked otherwise.
1914 ** ^There are three arguments to SQLITE_CONFIG_HEAP:
1915 ** An 8-byte aligned pointer to the memory,
1916 ** the number of bytes in the memory buffer, and the minimum allocation size.
1917 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1918 ** to using its default memory allocator (the system malloc() implementation),
1919 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
1920 ** memory pointer is not NULL then the alternative memory
1921 ** allocator is engaged to handle all of SQLites memory allocation needs.
1922 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1923 ** boundary or subsequent behavior of SQLite will be undefined.
1924 ** The minimum allocation size is capped at 2**12. Reasonable values
1925 ** for the minimum allocation size are 2**5 through 2**8.</dd>
1926 **
1927 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1928 ** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1929 ** pointer to an instance of the [sqlite3_mutex_methods] structure.
1930 ** The argument specifies alternative low-level mutex routines to be used
1931 ** in place the mutex routines built into SQLite.)^  ^SQLite makes a copy of
1932 ** the content of the [sqlite3_mutex_methods] structure before the call to
1933 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1934 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1935 ** the entire mutexing subsystem is omitted from the build and hence calls to
1936 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1937 ** return [SQLITE_ERROR].</dd>
1938 **
1939 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1940 ** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1941 ** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
1942 ** [sqlite3_mutex_methods]
1943 ** structure is filled with the currently defined mutex routines.)^
1944 ** This option can be used to overload the default mutex allocation
1945 ** routines with a wrapper used to track mutex usage for performance
1946 ** profiling or testing, for example.   ^If SQLite is compiled with
1947 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1948 ** the entire mutexing subsystem is omitted from the build and hence calls to
1949 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1950 ** return [SQLITE_ERROR].</dd>
1951 **
1952 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1953 ** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1954 ** the default size of lookaside memory on each [database connection].
1955 ** The first argument is the
1956 ** size of each lookaside buffer slot and the second is the number of
1957 ** slots allocated to each database connection.)^  ^(SQLITE_CONFIG_LOOKASIDE
1958 ** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1959 ** option to [sqlite3_db_config()] can be used to change the lookaside
1960 ** configuration on individual connections.)^ </dd>
1961 **
1962 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1963 ** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1964 ** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
1965 ** the interface to a custom page cache implementation.)^
1966 ** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1967 **
1968 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1969 ** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1970 ** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies of
1971 ** the current page cache implementation into that object.)^ </dd>
1972 **
1973 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1974 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1975 ** global [error log].
1976 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1977 ** function with a call signature of void(*)(void*,int,const char*),
1978 ** and a pointer to void. ^If the function pointer is not NULL, it is
1979 ** invoked by [sqlite3_log()] to process each logging event.  ^If the
1980 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1981 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1982 ** passed through as the first parameter to the application-defined logger
1983 ** function whenever that function is invoked.  ^The second parameter to
1984 ** the logger function is a copy of the first parameter to the corresponding
1985 ** [sqlite3_log()] call and is intended to be a [result code] or an
1986 ** [extended result code].  ^The third parameter passed to the logger is
1987 ** log message after formatting via [sqlite3_snprintf()].
1988 ** The SQLite logging interface is not reentrant; the logger function
1989 ** supplied by the application must not invoke any SQLite interface.
1990 ** In a multi-threaded application, the application-defined logger
1991 ** function must be threadsafe. </dd>
1992 **
1993 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1994 ** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1995 ** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1996 ** then URI handling is globally disabled.)^ ^If URI handling is globally
1997 ** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1998 ** [sqlite3_open16()] or
1999 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
2000 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
2001 ** connection is opened. ^If it is globally disabled, filenames are
2002 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
2003 ** database connection is opened. ^(By default, URI handling is globally
2004 ** disabled. The default value may be changed by compiling with the
2005 ** [SQLITE_USE_URI] symbol defined.)^
2006 **
2007 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
2008 ** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
2009 ** argument which is interpreted as a boolean in order to enable or disable
2010 ** the use of covering indices for full table scans in the query optimizer.
2011 ** ^The default setting is determined
2012 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
2013 ** if that compile-time option is omitted.
2014 ** The ability to disable the use of covering indices for full table scans
2015 ** is because some incorrectly coded legacy applications might malfunction
2016 ** when the optimization is enabled.  Providing the ability to
2017 ** disable the optimization allows the older, buggy application code to work
2018 ** without change even with newer versions of SQLite.
2019 **
2020 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
2021 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
2022 ** <dd> These options are obsolete and should not be used by new code.
2023 ** They are retained for backwards compatibility but are now no-ops.
2024 ** </dd>
2025 **
2026 ** [[SQLITE_CONFIG_SQLLOG]]
2027 ** <dt>SQLITE_CONFIG_SQLLOG
2028 ** <dd>This option is only available if sqlite is compiled with the
2029 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
2030 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
2031 ** The second should be of type (void*). The callback is invoked by the library
2032 ** in three separate circumstances, identified by the value passed as the
2033 ** fourth parameter. If the fourth parameter is 0, then the database connection
2034 ** passed as the second argument has just been opened. The third argument
2035 ** points to a buffer containing the name of the main database file. If the
2036 ** fourth parameter is 1, then the SQL statement that the third parameter
2037 ** points to has just been executed. Or, if the fourth parameter is 2, then
2038 ** the connection being passed as the second parameter is being closed. The
2039 ** third parameter is passed NULL In this case.  An example of using this
2040 ** configuration option can be seen in the "test_sqllog.c" source file in
2041 ** the canonical SQLite source tree.</dd>
2042 **
2043 ** [[SQLITE_CONFIG_MMAP_SIZE]]
2044 ** <dt>SQLITE_CONFIG_MMAP_SIZE
2045 ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
2046 ** that are the default mmap size limit (the default setting for
2047 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
2048 ** ^The default setting can be overridden by each database connection using
2049 ** either the [PRAGMA mmap_size] command, or by using the
2050 ** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
2051 ** will be silently truncated if necessary so that it does not exceed the
2052 ** compile-time maximum mmap size set by the
2053 ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
2054 ** ^If either argument to this option is negative, then that argument is
2055 ** changed to its compile-time default.
2056 **
2057 ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
2058 ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
2059 ** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
2060 ** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
2061 ** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
2062 ** that specifies the maximum size of the created heap.
2063 **
2064 ** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
2065 ** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
2066 ** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
2067 ** is a pointer to an integer and writes into that integer the number of extra
2068 ** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
2069 ** The amount of extra space required can change depending on the compiler,
2070 ** target platform, and SQLite version.
2071 **
2072 ** [[SQLITE_CONFIG_PMASZ]]
2073 ** <dt>SQLITE_CONFIG_PMASZ
2074 ** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
2075 ** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
2076 ** sorter to that integer.  The default minimum PMA Size is set by the
2077 ** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
2078 ** to help with sort operations when multithreaded sorting
2079 ** is enabled (using the [PRAGMA threads] command) and the amount of content
2080 ** to be sorted exceeds the page size times the minimum of the
2081 ** [PRAGMA cache_size] setting and this value.
2082 **
2083 ** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
2084 ** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
2085 ** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
2086 ** becomes the [statement journal] spill-to-disk threshold.
2087 ** [Statement journals] are held in memory until their size (in bytes)
2088 ** exceeds this threshold, at which point they are written to disk.
2089 ** Or if the threshold is -1, statement journals are always held
2090 ** exclusively in memory.
2091 ** Since many statement journals never become large, setting the spill
2092 ** threshold to a value such as 64KiB can greatly reduce the amount of
2093 ** I/O required to support statement rollback.
2094 ** The default value for this setting is controlled by the
2095 ** [SQLITE_STMTJRNL_SPILL] compile-time option.
2096 **
2097 ** [[SQLITE_CONFIG_SORTERREF_SIZE]]
2098 ** <dt>SQLITE_CONFIG_SORTERREF_SIZE
2099 ** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
2100 ** of type (int) - the new value of the sorter-reference size threshold.
2101 ** Usually, when SQLite uses an external sort to order records according
2102 ** to an ORDER BY clause, all fields required by the caller are present in the
2103 ** sorted records. However, if SQLite determines based on the declared type
2104 ** of a table column that its values are likely to be very large - larger
2105 ** than the configured sorter-reference size threshold - then a reference
2106 ** is stored in each sorted record and the required column values loaded
2107 ** from the database as records are returned in sorted order. The default
2108 ** value for this option is to never use this optimization. Specifying a
2109 ** negative value for this option restores the default behaviour.
2110 ** This option is only available if SQLite is compiled with the
2111 ** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
2112 **
2113 ** [[SQLITE_CONFIG_MEMDB_MAXSIZE]]
2114 ** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE
2115 ** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
2116 ** [sqlite3_int64] parameter which is the default maximum size for an in-memory
2117 ** database created using [sqlite3_deserialize()].  This default maximum
2118 ** size can be adjusted up or down for individual databases using the
2119 ** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control].  If this
2120 ** configuration setting is never used, then the default maximum is determined
2121 ** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option.  If that
2122 ** compile-time option is not set, then the default maximum is 1073741824.
2123 ** </dl>
2124 */
2125 #define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
2126 #define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
2127 #define SQLITE_CONFIG_SERIALIZED    3  /* nil */
2128 #define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
2129 #define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
2130 #define SQLITE_CONFIG_SCRATCH       6  /* No longer used */
2131 #define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
2132 #define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
2133 #define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
2134 #define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
2135 #define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
2136 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
2137 #define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
2138 #define SQLITE_CONFIG_PCACHE       14  /* no-op */
2139 #define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
2140 #define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
2141 #define SQLITE_CONFIG_URI          17  /* int */
2142 #define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
2143 #define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
2144 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
2145 #define SQLITE_CONFIG_SQLLOG       21  /* xSqllog, void* */
2146 #define SQLITE_CONFIG_MMAP_SIZE    22  /* sqlite3_int64, sqlite3_int64 */
2147 #define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
2148 #define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
2149 #define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
2150 #define SQLITE_CONFIG_STMTJRNL_SPILL      26  /* int nByte */
2151 #define SQLITE_CONFIG_SMALL_MALLOC        27  /* boolean */
2152 #define SQLITE_CONFIG_SORTERREF_SIZE      28  /* int nByte */
2153 #define SQLITE_CONFIG_MEMDB_MAXSIZE       29  /* sqlite3_int64 */
2154 
2155 /*
2156 ** CAPI3REF: Database Connection Configuration Options
2157 **
2158 ** These constants are the available integer configuration options that
2159 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
2160 **
2161 ** New configuration options may be added in future releases of SQLite.
2162 ** Existing configuration options might be discontinued.  Applications
2163 ** should check the return code from [sqlite3_db_config()] to make sure that
2164 ** the call worked.  ^The [sqlite3_db_config()] interface will return a
2165 ** non-zero [error code] if a discontinued or unsupported configuration option
2166 ** is invoked.
2167 **
2168 ** <dl>
2169 ** [[SQLITE_DBCONFIG_LOOKASIDE]]
2170 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
2171 ** <dd> ^This option takes three additional arguments that determine the
2172 ** [lookaside memory allocator] configuration for the [database connection].
2173 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
2174 ** pointer to a memory buffer to use for lookaside memory.
2175 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
2176 ** may be NULL in which case SQLite will allocate the
2177 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
2178 ** size of each lookaside buffer slot.  ^The third argument is the number of
2179 ** slots.  The size of the buffer in the first argument must be greater than
2180 ** or equal to the product of the second and third arguments.  The buffer
2181 ** must be aligned to an 8-byte boundary.  ^If the second argument to
2182 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
2183 ** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
2184 ** configuration for a database connection can only be changed when that
2185 ** connection is not currently using lookaside memory, or in other words
2186 ** when the "current value" returned by
2187 ** [sqlite3_db_status](D,[SQLITE_DBSTATUS_LOOKASIDE_USED],...) is zero.
2188 ** Any attempt to change the lookaside memory configuration when lookaside
2189 ** memory is in use leaves the configuration unchanged and returns
2190 ** [SQLITE_BUSY].)^</dd>
2191 **
2192 ** [[SQLITE_DBCONFIG_ENABLE_FKEY]]
2193 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
2194 ** <dd> ^This option is used to enable or disable the enforcement of
2195 ** [foreign key constraints].  There should be two additional arguments.
2196 ** The first argument is an integer which is 0 to disable FK enforcement,
2197 ** positive to enable FK enforcement or negative to leave FK enforcement
2198 ** unchanged.  The second parameter is a pointer to an integer into which
2199 ** is written 0 or 1 to indicate whether FK enforcement is off or on
2200 ** following this call.  The second parameter may be a NULL pointer, in
2201 ** which case the FK enforcement setting is not reported back. </dd>
2202 **
2203 ** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]]
2204 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
2205 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
2206 ** There should be two additional arguments.
2207 ** The first argument is an integer which is 0 to disable triggers,
2208 ** positive to enable triggers or negative to leave the setting unchanged.
2209 ** The second parameter is a pointer to an integer into which
2210 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
2211 ** following this call.  The second parameter may be a NULL pointer, in
2212 ** which case the trigger setting is not reported back.
2213 **
2214 ** <p>Originally this option disabled all triggers.  ^(However, since
2215 ** SQLite version 3.35.0, TEMP triggers are still allowed even if
2216 ** this option is off.  So, in other words, this option now only disables
2217 ** triggers in the main database schema or in the schemas of ATTACH-ed
2218 ** databases.)^ </dd>
2219 **
2220 ** [[SQLITE_DBCONFIG_ENABLE_VIEW]]
2221 ** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt>
2222 ** <dd> ^This option is used to enable or disable [CREATE VIEW | views].
2223 ** There should be two additional arguments.
2224 ** The first argument is an integer which is 0 to disable views,
2225 ** positive to enable views or negative to leave the setting unchanged.
2226 ** The second parameter is a pointer to an integer into which
2227 ** is written 0 or 1 to indicate whether views are disabled or enabled
2228 ** following this call.  The second parameter may be a NULL pointer, in
2229 ** which case the view setting is not reported back.
2230 **
2231 ** <p>Originally this option disabled all views.  ^(However, since
2232 ** SQLite version 3.35.0, TEMP views are still allowed even if
2233 ** this option is off.  So, in other words, this option now only disables
2234 ** views in the main database schema or in the schemas of ATTACH-ed
2235 ** databases.)^ </dd>
2236 **
2237 ** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]]
2238 ** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
2239 ** <dd> ^This option is used to enable or disable the
2240 ** [fts3_tokenizer()] function which is part of the
2241 ** [FTS3] full-text search engine extension.
2242 ** There should be two additional arguments.
2243 ** The first argument is an integer which is 0 to disable fts3_tokenizer() or
2244 ** positive to enable fts3_tokenizer() or negative to leave the setting
2245 ** unchanged.
2246 ** The second parameter is a pointer to an integer into which
2247 ** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
2248 ** following this call.  The second parameter may be a NULL pointer, in
2249 ** which case the new setting is not reported back. </dd>
2250 **
2251 ** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]]
2252 ** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
2253 ** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
2254 ** interface independently of the [load_extension()] SQL function.
2255 ** The [sqlite3_enable_load_extension()] API enables or disables both the
2256 ** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
2257 ** There should be two additional arguments.
2258 ** When the first argument to this interface is 1, then only the C-API is
2259 ** enabled and the SQL function remains disabled.  If the first argument to
2260 ** this interface is 0, then both the C-API and the SQL function are disabled.
2261 ** If the first argument is -1, then no changes are made to state of either the
2262 ** C-API or the SQL function.
2263 ** The second parameter is a pointer to an integer into which
2264 ** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
2265 ** is disabled or enabled following this call.  The second parameter may
2266 ** be a NULL pointer, in which case the new setting is not reported back.
2267 ** </dd>
2268 **
2269 ** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
2270 ** <dd> ^This option is used to change the name of the "main" database
2271 ** schema.  ^The sole argument is a pointer to a constant UTF8 string
2272 ** which will become the new schema name in place of "main".  ^SQLite
2273 ** does not make a copy of the new main schema name string, so the application
2274 ** must ensure that the argument passed into this DBCONFIG option is unchanged
2275 ** until after the database connection closes.
2276 ** </dd>
2277 **
2278 ** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]]
2279 ** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
2280 ** <dd> Usually, when a database in wal mode is closed or detached from a
2281 ** database handle, SQLite checks if this will mean that there are now no
2282 ** connections at all to the database. If so, it performs a checkpoint
2283 ** operation before closing the connection. This option may be used to
2284 ** override this behaviour. The first parameter passed to this operation
2285 ** is an integer - positive to disable checkpoints-on-close, or zero (the
2286 ** default) to enable them, and negative to leave the setting unchanged.
2287 ** The second parameter is a pointer to an integer
2288 ** into which is written 0 or 1 to indicate whether checkpoints-on-close
2289 ** have been disabled - 0 if they are not disabled, 1 if they are.
2290 ** </dd>
2291 **
2292 ** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
2293 ** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
2294 ** the [query planner stability guarantee] (QPSG).  When the QPSG is active,
2295 ** a single SQL query statement will always use the same algorithm regardless
2296 ** of values of [bound parameters].)^ The QPSG disables some query optimizations
2297 ** that look at the values of bound parameters, which can make some queries
2298 ** slower.  But the QPSG has the advantage of more predictable behavior.  With
2299 ** the QPSG active, SQLite will always use the same query plan in the field as
2300 ** was used during testing in the lab.
2301 ** The first argument to this setting is an integer which is 0 to disable
2302 ** the QPSG, positive to enable QPSG, or negative to leave the setting
2303 ** unchanged. The second parameter is a pointer to an integer into which
2304 ** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
2305 ** following this call.
2306 ** </dd>
2307 **
2308 ** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
2309 ** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
2310 ** include output for any operations performed by trigger programs. This
2311 ** option is used to set or clear (the default) a flag that governs this
2312 ** behavior. The first parameter passed to this operation is an integer -
2313 ** positive to enable output for trigger programs, or zero to disable it,
2314 ** or negative to leave the setting unchanged.
2315 ** The second parameter is a pointer to an integer into which is written
2316 ** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
2317 ** it is not disabled, 1 if it is.
2318 ** </dd>
2319 **
2320 ** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
2321 ** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
2322 ** [VACUUM] in order to reset a database back to an empty database
2323 ** with no schema and no content. The following process works even for
2324 ** a badly corrupted database file:
2325 ** <ol>
2326 ** <li> If the database connection is newly opened, make sure it has read the
2327 **      database schema by preparing then discarding some query against the
2328 **      database, or calling sqlite3_table_column_metadata(), ignoring any
2329 **      errors.  This step is only necessary if the application desires to keep
2330 **      the database in WAL mode after the reset if it was in WAL mode before
2331 **      the reset.
2332 ** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
2333 ** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
2334 ** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
2335 ** </ol>
2336 ** Because resetting a database is destructive and irreversible, the
2337 ** process requires the use of this obscure API and multiple steps to
2338 ** help ensure that it does not happen by accident. Because this
2339 ** feature must be capable of resetting corrupt databases, and
2340 ** shutting down virtual tables may require access to that corrupt
2341 ** storage, the library must abandon any installed virtual tables
2342 ** without calling their xDestroy() methods.
2343 **
2344 ** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
2345 ** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
2346 ** "defensive" flag for a database connection.  When the defensive
2347 ** flag is enabled, language features that allow ordinary SQL to
2348 ** deliberately corrupt the database file are disabled.  The disabled
2349 ** features include but are not limited to the following:
2350 ** <ul>
2351 ** <li> The [PRAGMA writable_schema=ON] statement.
2352 ** <li> The [PRAGMA journal_mode=OFF] statement.
2353 ** <li> The [PRAGMA schema_version=N] statement.
2354 ** <li> Writes to the [sqlite_dbpage] virtual table.
2355 ** <li> Direct writes to [shadow tables].
2356 ** </ul>
2357 ** </dd>
2358 **
2359 ** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt>
2360 ** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
2361 ** "writable_schema" flag. This has the same effect and is logically equivalent
2362 ** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF].
2363 ** The first argument to this setting is an integer which is 0 to disable
2364 ** the writable_schema, positive to enable writable_schema, or negative to
2365 ** leave the setting unchanged. The second parameter is a pointer to an
2366 ** integer into which is written 0 or 1 to indicate whether the writable_schema
2367 ** is enabled or disabled following this call.
2368 ** </dd>
2369 **
2370 ** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]]
2371 ** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt>
2372 ** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates
2373 ** the legacy behavior of the [ALTER TABLE RENAME] command such it
2374 ** behaves as it did prior to [version 3.24.0] (2018-06-04).  See the
2375 ** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for
2376 ** additional information. This feature can also be turned on and off
2377 ** using the [PRAGMA legacy_alter_table] statement.
2378 ** </dd>
2379 **
2380 ** [[SQLITE_DBCONFIG_DQS_DML]]
2381 ** <dt>SQLITE_DBCONFIG_DQS_DML</td>
2382 ** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates
2383 ** the legacy [double-quoted string literal] misfeature for DML statements
2384 ** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The
2385 ** default value of this setting is determined by the [-DSQLITE_DQS]
2386 ** compile-time option.
2387 ** </dd>
2388 **
2389 ** [[SQLITE_DBCONFIG_DQS_DDL]]
2390 ** <dt>SQLITE_DBCONFIG_DQS_DDL</td>
2391 ** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates
2392 ** the legacy [double-quoted string literal] misfeature for DDL statements,
2393 ** such as CREATE TABLE and CREATE INDEX. The
2394 ** default value of this setting is determined by the [-DSQLITE_DQS]
2395 ** compile-time option.
2396 ** </dd>
2397 **
2398 ** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]]
2399 ** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</td>
2400 ** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to
2401 ** assume that database schemas are untainted by malicious content.
2402 ** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite
2403 ** takes additional defensive steps to protect the application from harm
2404 ** including:
2405 ** <ul>
2406 ** <li> Prohibit the use of SQL functions inside triggers, views,
2407 ** CHECK constraints, DEFAULT clauses, expression indexes,
2408 ** partial indexes, or generated columns
2409 ** unless those functions are tagged with [SQLITE_INNOCUOUS].
2410 ** <li> Prohibit the use of virtual tables inside of triggers or views
2411 ** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS].
2412 ** </ul>
2413 ** This setting defaults to "on" for legacy compatibility, however
2414 ** all applications are advised to turn it off if possible. This setting
2415 ** can also be controlled using the [PRAGMA trusted_schema] statement.
2416 ** </dd>
2417 **
2418 ** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]]
2419 ** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</td>
2420 ** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates
2421 ** the legacy file format flag.  When activated, this flag causes all newly
2422 ** created database file to have a schema format version number (the 4-byte
2423 ** integer found at offset 44 into the database header) of 1.  This in turn
2424 ** means that the resulting database file will be readable and writable by
2425 ** any SQLite version back to 3.0.0 ([dateof:3.0.0]).  Without this setting,
2426 ** newly created databases are generally not understandable by SQLite versions
2427 ** prior to 3.3.0 ([dateof:3.3.0]).  As these words are written, there
2428 ** is now scarcely any need to generated database files that are compatible
2429 ** all the way back to version 3.0.0, and so this setting is of little
2430 ** practical use, but is provided so that SQLite can continue to claim the
2431 ** ability to generate new database files that are compatible with  version
2432 ** 3.0.0.
2433 ** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on,
2434 ** the [VACUUM] command will fail with an obscure error when attempting to
2435 ** process a table with generated columns and a descending index.  This is
2436 ** not considered a bug since SQLite versions 3.3.0 and earlier do not support
2437 ** either generated columns or decending indexes.
2438 ** </dd>
2439 ** </dl>
2440 */
2441 #define SQLITE_DBCONFIG_MAINDBNAME            1000 /* const char* */
2442 #define SQLITE_DBCONFIG_LOOKASIDE             1001 /* void* int int */
2443 #define SQLITE_DBCONFIG_ENABLE_FKEY           1002 /* int int* */
2444 #define SQLITE_DBCONFIG_ENABLE_TRIGGER        1003 /* int int* */
2445 #define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
2446 #define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
2447 #define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE      1006 /* int int* */
2448 #define SQLITE_DBCONFIG_ENABLE_QPSG           1007 /* int int* */
2449 #define SQLITE_DBCONFIG_TRIGGER_EQP           1008 /* int int* */
2450 #define SQLITE_DBCONFIG_RESET_DATABASE        1009 /* int int* */
2451 #define SQLITE_DBCONFIG_DEFENSIVE             1010 /* int int* */
2452 #define SQLITE_DBCONFIG_WRITABLE_SCHEMA       1011 /* int int* */
2453 #define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE    1012 /* int int* */
2454 #define SQLITE_DBCONFIG_DQS_DML               1013 /* int int* */
2455 #define SQLITE_DBCONFIG_DQS_DDL               1014 /* int int* */
2456 #define SQLITE_DBCONFIG_ENABLE_VIEW           1015 /* int int* */
2457 #define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT    1016 /* int int* */
2458 #define SQLITE_DBCONFIG_TRUSTED_SCHEMA        1017 /* int int* */
2459 #define SQLITE_DBCONFIG_MAX                   1017 /* Largest DBCONFIG */
2460 
2461 /*
2462 ** CAPI3REF: Enable Or Disable Extended Result Codes
2463 ** METHOD: sqlite3
2464 **
2465 ** ^The sqlite3_extended_result_codes() routine enables or disables the
2466 ** [extended result codes] feature of SQLite. ^The extended result
2467 ** codes are disabled by default for historical compatibility.
2468 */
2469 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
2470 
2471 /*
2472 ** CAPI3REF: Last Insert Rowid
2473 ** METHOD: sqlite3
2474 **
2475 ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
2476 ** has a unique 64-bit signed
2477 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
2478 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
2479 ** names are not also used by explicitly declared columns. ^If
2480 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
2481 ** is another alias for the rowid.
2482 **
2483 ** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
2484 ** the most recent successful [INSERT] into a rowid table or [virtual table]
2485 ** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
2486 ** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
2487 ** on the database connection D, then sqlite3_last_insert_rowid(D) returns
2488 ** zero.
2489 **
2490 ** As well as being set automatically as rows are inserted into database
2491 ** tables, the value returned by this function may be set explicitly by
2492 ** [sqlite3_set_last_insert_rowid()]
2493 **
2494 ** Some virtual table implementations may INSERT rows into rowid tables as
2495 ** part of committing a transaction (e.g. to flush data accumulated in memory
2496 ** to disk). In this case subsequent calls to this function return the rowid
2497 ** associated with these internal INSERT operations, which leads to
2498 ** unintuitive results. Virtual table implementations that do write to rowid
2499 ** tables in this way can avoid this problem by restoring the original
2500 ** rowid value using [sqlite3_set_last_insert_rowid()] before returning
2501 ** control to the user.
2502 **
2503 ** ^(If an [INSERT] occurs within a trigger then this routine will
2504 ** return the [rowid] of the inserted row as long as the trigger is
2505 ** running. Once the trigger program ends, the value returned
2506 ** by this routine reverts to what it was before the trigger was fired.)^
2507 **
2508 ** ^An [INSERT] that fails due to a constraint violation is not a
2509 ** successful [INSERT] and does not change the value returned by this
2510 ** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
2511 ** and INSERT OR ABORT make no changes to the return value of this
2512 ** routine when their insertion fails.  ^(When INSERT OR REPLACE
2513 ** encounters a constraint violation, it does not fail.  The
2514 ** INSERT continues to completion after deleting rows that caused
2515 ** the constraint problem so INSERT OR REPLACE will always change
2516 ** the return value of this interface.)^
2517 **
2518 ** ^For the purposes of this routine, an [INSERT] is considered to
2519 ** be successful even if it is subsequently rolled back.
2520 **
2521 ** This function is accessible to SQL statements via the
2522 ** [last_insert_rowid() SQL function].
2523 **
2524 ** If a separate thread performs a new [INSERT] on the same
2525 ** database connection while the [sqlite3_last_insert_rowid()]
2526 ** function is running and thus changes the last insert [rowid],
2527 ** then the value returned by [sqlite3_last_insert_rowid()] is
2528 ** unpredictable and might not equal either the old or the new
2529 ** last insert [rowid].
2530 */
2531 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
2532 
2533 /*
2534 ** CAPI3REF: Set the Last Insert Rowid value.
2535 ** METHOD: sqlite3
2536 **
2537 ** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
2538 ** set the value returned by calling sqlite3_last_insert_rowid(D) to R
2539 ** without inserting a row into the database.
2540 */
2541 SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
2542 
2543 /*
2544 ** CAPI3REF: Count The Number Of Rows Modified
2545 ** METHOD: sqlite3
2546 **
2547 ** ^These functions return the number of rows modified, inserted or
2548 ** deleted by the most recently completed INSERT, UPDATE or DELETE
2549 ** statement on the database connection specified by the only parameter.
2550 ** The two functions are identical except for the type of the return value
2551 ** and that if the number of rows modified by the most recent INSERT, UPDATE
2552 ** or DELETE is greater than the maximum value supported by type "int", then
2553 ** the return value of sqlite3_changes() is undefined. ^Executing any other
2554 ** type of SQL statement does not modify the value returned by these functions.
2555 **
2556 ** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
2557 ** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
2558 ** [foreign key actions] or [REPLACE] constraint resolution are not counted.
2559 **
2560 ** Changes to a view that are intercepted by
2561 ** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
2562 ** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
2563 ** DELETE statement run on a view is always zero. Only changes made to real
2564 ** tables are counted.
2565 **
2566 ** Things are more complicated if the sqlite3_changes() function is
2567 ** executed while a trigger program is running. This may happen if the
2568 ** program uses the [changes() SQL function], or if some other callback
2569 ** function invokes sqlite3_changes() directly. Essentially:
2570 **
2571 ** <ul>
2572 **   <li> ^(Before entering a trigger program the value returned by
2573 **        sqlite3_changes() function is saved. After the trigger program
2574 **        has finished, the original value is restored.)^
2575 **
2576 **   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
2577 **        statement sets the value returned by sqlite3_changes()
2578 **        upon completion as normal. Of course, this value will not include
2579 **        any changes performed by sub-triggers, as the sqlite3_changes()
2580 **        value will be saved and restored after each sub-trigger has run.)^
2581 ** </ul>
2582 **
2583 ** ^This means that if the changes() SQL function (or similar) is used
2584 ** by the first INSERT, UPDATE or DELETE statement within a trigger, it
2585 ** returns the value as set when the calling statement began executing.
2586 ** ^If it is used by the second or subsequent such statement within a trigger
2587 ** program, the value returned reflects the number of rows modified by the
2588 ** previous INSERT, UPDATE or DELETE statement within the same trigger.
2589 **
2590 ** If a separate thread makes changes on the same database connection
2591 ** while [sqlite3_changes()] is running then the value returned
2592 ** is unpredictable and not meaningful.
2593 **
2594 ** See also:
2595 ** <ul>
2596 ** <li> the [sqlite3_total_changes()] interface
2597 ** <li> the [count_changes pragma]
2598 ** <li> the [changes() SQL function]
2599 ** <li> the [data_version pragma]
2600 ** </ul>
2601 */
2602 SQLITE_API int sqlite3_changes(sqlite3*);
2603 SQLITE_API sqlite3_int64 sqlite3_changes64(sqlite3*);
2604 
2605 /*
2606 ** CAPI3REF: Total Number Of Rows Modified
2607 ** METHOD: sqlite3
2608 **
2609 ** ^These functions return the total number of rows inserted, modified or
2610 ** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2611 ** since the database connection was opened, including those executed as
2612 ** part of trigger programs. The two functions are identical except for the
2613 ** type of the return value and that if the number of rows modified by the
2614 ** connection exceeds the maximum value supported by type "int", then
2615 ** the return value of sqlite3_total_changes() is undefined. ^Executing
2616 ** any other type of SQL statement does not affect the value returned by
2617 ** sqlite3_total_changes().
2618 **
2619 ** ^Changes made as part of [foreign key actions] are included in the
2620 ** count, but those made as part of REPLACE constraint resolution are
2621 ** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2622 ** are not counted.
2623 **
2624 ** The [sqlite3_total_changes(D)] interface only reports the number
2625 ** of rows that changed due to SQL statement run against database
2626 ** connection D.  Any changes by other database connections are ignored.
2627 ** To detect changes against a database file from other database
2628 ** connections use the [PRAGMA data_version] command or the
2629 ** [SQLITE_FCNTL_DATA_VERSION] [file control].
2630 **
2631 ** If a separate thread makes changes on the same database connection
2632 ** while [sqlite3_total_changes()] is running then the value
2633 ** returned is unpredictable and not meaningful.
2634 **
2635 ** See also:
2636 ** <ul>
2637 ** <li> the [sqlite3_changes()] interface
2638 ** <li> the [count_changes pragma]
2639 ** <li> the [changes() SQL function]
2640 ** <li> the [data_version pragma]
2641 ** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control]
2642 ** </ul>
2643 */
2644 SQLITE_API int sqlite3_total_changes(sqlite3*);
2645 SQLITE_API sqlite3_int64 sqlite3_total_changes64(sqlite3*);
2646 
2647 /*
2648 ** CAPI3REF: Interrupt A Long-Running Query
2649 ** METHOD: sqlite3
2650 **
2651 ** ^This function causes any pending database operation to abort and
2652 ** return at its earliest opportunity. This routine is typically
2653 ** called in response to a user action such as pressing "Cancel"
2654 ** or Ctrl-C where the user wants a long query operation to halt
2655 ** immediately.
2656 **
2657 ** ^It is safe to call this routine from a thread different from the
2658 ** thread that is currently running the database operation.  But it
2659 ** is not safe to call this routine with a [database connection] that
2660 ** is closed or might close before sqlite3_interrupt() returns.
2661 **
2662 ** ^If an SQL operation is very nearly finished at the time when
2663 ** sqlite3_interrupt() is called, then it might not have an opportunity
2664 ** to be interrupted and might continue to completion.
2665 **
2666 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2667 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2668 ** that is inside an explicit transaction, then the entire transaction
2669 ** will be rolled back automatically.
2670 **
2671 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
2672 ** SQL statements on [database connection] D complete.  ^Any new SQL statements
2673 ** that are started after the sqlite3_interrupt() call and before the
2674 ** running statement count reaches zero are interrupted as if they had been
2675 ** running prior to the sqlite3_interrupt() call.  ^New SQL statements
2676 ** that are started after the running statement count reaches zero are
2677 ** not effected by the sqlite3_interrupt().
2678 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2679 ** SQL statements is a no-op and has no effect on SQL statements
2680 ** that are started after the sqlite3_interrupt() call returns.
2681 **
2682 ** ^The [sqlite3_is_interrupted(D)] interface can be used to determine whether
2683 ** or not an interrupt is currently in effect for [database connection] D.
2684 */
2685 SQLITE_API void sqlite3_interrupt(sqlite3*);
2686 SQLITE_API int sqlite3_is_interrupted(sqlite3*);
2687 
2688 /*
2689 ** CAPI3REF: Determine If An SQL Statement Is Complete
2690 **
2691 ** These routines are useful during command-line input to determine if the
2692 ** currently entered text seems to form a complete SQL statement or
2693 ** if additional input is needed before sending the text into
2694 ** SQLite for parsing.  ^These routines return 1 if the input string
2695 ** appears to be a complete SQL statement.  ^A statement is judged to be
2696 ** complete if it ends with a semicolon token and is not a prefix of a
2697 ** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
2698 ** string literals or quoted identifier names or comments are not
2699 ** independent tokens (they are part of the token in which they are
2700 ** embedded) and thus do not count as a statement terminator.  ^Whitespace
2701 ** and comments that follow the final semicolon are ignored.
2702 **
2703 ** ^These routines return 0 if the statement is incomplete.  ^If a
2704 ** memory allocation fails, then SQLITE_NOMEM is returned.
2705 **
2706 ** ^These routines do not parse the SQL statements thus
2707 ** will not detect syntactically incorrect SQL.
2708 **
2709 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2710 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2711 ** automatically by sqlite3_complete16().  If that initialization fails,
2712 ** then the return value from sqlite3_complete16() will be non-zero
2713 ** regardless of whether or not the input SQL is complete.)^
2714 **
2715 ** The input to [sqlite3_complete()] must be a zero-terminated
2716 ** UTF-8 string.
2717 **
2718 ** The input to [sqlite3_complete16()] must be a zero-terminated
2719 ** UTF-16 string in native byte order.
2720 */
2721 SQLITE_API int sqlite3_complete(const char *sql);
2722 SQLITE_API int sqlite3_complete16(const void *sql);
2723 
2724 /*
2725 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2726 ** KEYWORDS: {busy-handler callback} {busy handler}
2727 ** METHOD: sqlite3
2728 **
2729 ** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2730 ** that might be invoked with argument P whenever
2731 ** an attempt is made to access a database table associated with
2732 ** [database connection] D when another thread
2733 ** or process has the table locked.
2734 ** The sqlite3_busy_handler() interface is used to implement
2735 ** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2736 **
2737 ** ^If the busy callback is NULL, then [SQLITE_BUSY]
2738 ** is returned immediately upon encountering the lock.  ^If the busy callback
2739 ** is not NULL, then the callback might be invoked with two arguments.
2740 **
2741 ** ^The first argument to the busy handler is a copy of the void* pointer which
2742 ** is the third argument to sqlite3_busy_handler().  ^The second argument to
2743 ** the busy handler callback is the number of times that the busy handler has
2744 ** been invoked previously for the same locking event.  ^If the
2745 ** busy callback returns 0, then no additional attempts are made to
2746 ** access the database and [SQLITE_BUSY] is returned
2747 ** to the application.
2748 ** ^If the callback returns non-zero, then another attempt
2749 ** is made to access the database and the cycle repeats.
2750 **
2751 ** The presence of a busy handler does not guarantee that it will be invoked
2752 ** when there is lock contention. ^If SQLite determines that invoking the busy
2753 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2754 ** to the application instead of invoking the
2755 ** busy handler.
2756 ** Consider a scenario where one process is holding a read lock that
2757 ** it is trying to promote to a reserved lock and
2758 ** a second process is holding a reserved lock that it is trying
2759 ** to promote to an exclusive lock.  The first process cannot proceed
2760 ** because it is blocked by the second and the second process cannot
2761 ** proceed because it is blocked by the first.  If both processes
2762 ** invoke the busy handlers, neither will make any progress.  Therefore,
2763 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2764 ** will induce the first process to release its read lock and allow
2765 ** the second process to proceed.
2766 **
2767 ** ^The default busy callback is NULL.
2768 **
2769 ** ^(There can only be a single busy handler defined for each
2770 ** [database connection].  Setting a new busy handler clears any
2771 ** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
2772 ** or evaluating [PRAGMA busy_timeout=N] will change the
2773 ** busy handler and thus clear any previously set busy handler.
2774 **
2775 ** The busy callback should not take any actions which modify the
2776 ** database connection that invoked the busy handler.  In other words,
2777 ** the busy handler is not reentrant.  Any such actions
2778 ** result in undefined behavior.
2779 **
2780 ** A busy handler must not close the database connection
2781 ** or [prepared statement] that invoked the busy handler.
2782 */
2783 SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
2784 
2785 /*
2786 ** CAPI3REF: Set A Busy Timeout
2787 ** METHOD: sqlite3
2788 **
2789 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2790 ** for a specified amount of time when a table is locked.  ^The handler
2791 ** will sleep multiple times until at least "ms" milliseconds of sleeping
2792 ** have accumulated.  ^After at least "ms" milliseconds of sleeping,
2793 ** the handler returns 0 which causes [sqlite3_step()] to return
2794 ** [SQLITE_BUSY].
2795 **
2796 ** ^Calling this routine with an argument less than or equal to zero
2797 ** turns off all busy handlers.
2798 **
2799 ** ^(There can only be a single busy handler for a particular
2800 ** [database connection] at any given moment.  If another busy handler
2801 ** was defined  (using [sqlite3_busy_handler()]) prior to calling
2802 ** this routine, that other busy handler is cleared.)^
2803 **
2804 ** See also:  [PRAGMA busy_timeout]
2805 */
2806 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2807 
2808 /*
2809 ** CAPI3REF: Convenience Routines For Running Queries
2810 ** METHOD: sqlite3
2811 **
2812 ** This is a legacy interface that is preserved for backwards compatibility.
2813 ** Use of this interface is not recommended.
2814 **
2815 ** Definition: A <b>result table</b> is memory data structure created by the
2816 ** [sqlite3_get_table()] interface.  A result table records the
2817 ** complete query results from one or more queries.
2818 **
2819 ** The table conceptually has a number of rows and columns.  But
2820 ** these numbers are not part of the result table itself.  These
2821 ** numbers are obtained separately.  Let N be the number of rows
2822 ** and M be the number of columns.
2823 **
2824 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2825 ** There are (N+1)*M elements in the array.  The first M pointers point
2826 ** to zero-terminated strings that  contain the names of the columns.
2827 ** The remaining entries all point to query results.  NULL values result
2828 ** in NULL pointers.  All other values are in their UTF-8 zero-terminated
2829 ** string representation as returned by [sqlite3_column_text()].
2830 **
2831 ** A result table might consist of one or more memory allocations.
2832 ** It is not safe to pass a result table directly to [sqlite3_free()].
2833 ** A result table should be deallocated using [sqlite3_free_table()].
2834 **
2835 ** ^(As an example of the result table format, suppose a query result
2836 ** is as follows:
2837 **
2838 ** <blockquote><pre>
2839 **        Name        | Age
2840 **        -----------------------
2841 **        Alice       | 43
2842 **        Bob         | 28
2843 **        Cindy       | 21
2844 ** </pre></blockquote>
2845 **
2846 ** There are two columns (M==2) and three rows (N==3).  Thus the
2847 ** result table has 8 entries.  Suppose the result table is stored
2848 ** in an array named azResult.  Then azResult holds this content:
2849 **
2850 ** <blockquote><pre>
2851 **        azResult&#91;0] = "Name";
2852 **        azResult&#91;1] = "Age";
2853 **        azResult&#91;2] = "Alice";
2854 **        azResult&#91;3] = "43";
2855 **        azResult&#91;4] = "Bob";
2856 **        azResult&#91;5] = "28";
2857 **        azResult&#91;6] = "Cindy";
2858 **        azResult&#91;7] = "21";
2859 ** </pre></blockquote>)^
2860 **
2861 ** ^The sqlite3_get_table() function evaluates one or more
2862 ** semicolon-separated SQL statements in the zero-terminated UTF-8
2863 ** string of its 2nd parameter and returns a result table to the
2864 ** pointer given in its 3rd parameter.
2865 **
2866 ** After the application has finished with the result from sqlite3_get_table(),
2867 ** it must pass the result table pointer to sqlite3_free_table() in order to
2868 ** release the memory that was malloced.  Because of the way the
2869 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2870 ** function must not try to call [sqlite3_free()] directly.  Only
2871 ** [sqlite3_free_table()] is able to release the memory properly and safely.
2872 **
2873 ** The sqlite3_get_table() interface is implemented as a wrapper around
2874 ** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
2875 ** to any internal data structures of SQLite.  It uses only the public
2876 ** interface defined here.  As a consequence, errors that occur in the
2877 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2878 ** reflected in subsequent calls to [sqlite3_errcode()] or
2879 ** [sqlite3_errmsg()].
2880 */
2881 SQLITE_API int sqlite3_get_table(
2882   sqlite3 *db,          /* An open database */
2883   const char *zSql,     /* SQL to be evaluated */
2884   char ***pazResult,    /* Results of the query */
2885   int *pnRow,           /* Number of result rows written here */
2886   int *pnColumn,        /* Number of result columns written here */
2887   char **pzErrmsg       /* Error msg written here */
2888 );
2889 SQLITE_API void sqlite3_free_table(char **result);
2890 
2891 /*
2892 ** CAPI3REF: Formatted String Printing Functions
2893 **
2894 ** These routines are work-alikes of the "printf()" family of functions
2895 ** from the standard C library.
2896 ** These routines understand most of the common formatting options from
2897 ** the standard library printf()
2898 ** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
2899 ** See the [built-in printf()] documentation for details.
2900 **
2901 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2902 ** results into memory obtained from [sqlite3_malloc64()].
2903 ** The strings returned by these two routines should be
2904 ** released by [sqlite3_free()].  ^Both routines return a
2905 ** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
2906 ** memory to hold the resulting string.
2907 **
2908 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2909 ** the standard C library.  The result is written into the
2910 ** buffer supplied as the second parameter whose size is given by
2911 ** the first parameter. Note that the order of the
2912 ** first two parameters is reversed from snprintf().)^  This is an
2913 ** historical accident that cannot be fixed without breaking
2914 ** backwards compatibility.  ^(Note also that sqlite3_snprintf()
2915 ** returns a pointer to its buffer instead of the number of
2916 ** characters actually written into the buffer.)^  We admit that
2917 ** the number of characters written would be a more useful return
2918 ** value but we cannot change the implementation of sqlite3_snprintf()
2919 ** now without breaking compatibility.
2920 **
2921 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2922 ** guarantees that the buffer is always zero-terminated.  ^The first
2923 ** parameter "n" is the total size of the buffer, including space for
2924 ** the zero terminator.  So the longest string that can be completely
2925 ** written will be n-1 characters.
2926 **
2927 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2928 **
2929 ** See also:  [built-in printf()], [printf() SQL function]
2930 */
2931 SQLITE_API char *sqlite3_mprintf(const char*,...);
2932 SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2933 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2934 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2935 
2936 /*
2937 ** CAPI3REF: Memory Allocation Subsystem
2938 **
2939 ** The SQLite core uses these three routines for all of its own
2940 ** internal memory allocation needs. "Core" in the previous sentence
2941 ** does not include operating-system specific [VFS] implementation.  The
2942 ** Windows VFS uses native malloc() and free() for some operations.
2943 **
2944 ** ^The sqlite3_malloc() routine returns a pointer to a block
2945 ** of memory at least N bytes in length, where N is the parameter.
2946 ** ^If sqlite3_malloc() is unable to obtain sufficient free
2947 ** memory, it returns a NULL pointer.  ^If the parameter N to
2948 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2949 ** a NULL pointer.
2950 **
2951 ** ^The sqlite3_malloc64(N) routine works just like
2952 ** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2953 ** of a signed 32-bit integer.
2954 **
2955 ** ^Calling sqlite3_free() with a pointer previously returned
2956 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2957 ** that it might be reused.  ^The sqlite3_free() routine is
2958 ** a no-op if is called with a NULL pointer.  Passing a NULL pointer
2959 ** to sqlite3_free() is harmless.  After being freed, memory
2960 ** should neither be read nor written.  Even reading previously freed
2961 ** memory might result in a segmentation fault or other severe error.
2962 ** Memory corruption, a segmentation fault, or other severe error
2963 ** might result if sqlite3_free() is called with a non-NULL pointer that
2964 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2965 **
2966 ** ^The sqlite3_realloc(X,N) interface attempts to resize a
2967 ** prior memory allocation X to be at least N bytes.
2968 ** ^If the X parameter to sqlite3_realloc(X,N)
2969 ** is a NULL pointer then its behavior is identical to calling
2970 ** sqlite3_malloc(N).
2971 ** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2972 ** negative then the behavior is exactly the same as calling
2973 ** sqlite3_free(X).
2974 ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2975 ** of at least N bytes in size or NULL if insufficient memory is available.
2976 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2977 ** of the prior allocation are copied into the beginning of buffer returned
2978 ** by sqlite3_realloc(X,N) and the prior allocation is freed.
2979 ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2980 ** prior allocation is not freed.
2981 **
2982 ** ^The sqlite3_realloc64(X,N) interfaces works the same as
2983 ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2984 ** of a 32-bit signed integer.
2985 **
2986 ** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2987 ** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2988 ** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2989 ** ^The value returned by sqlite3_msize(X) might be larger than the number
2990 ** of bytes requested when X was allocated.  ^If X is a NULL pointer then
2991 ** sqlite3_msize(X) returns zero.  If X points to something that is not
2992 ** the beginning of memory allocation, or if it points to a formerly
2993 ** valid memory allocation that has now been freed, then the behavior
2994 ** of sqlite3_msize(X) is undefined and possibly harmful.
2995 **
2996 ** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2997 ** sqlite3_malloc64(), and sqlite3_realloc64()
2998 ** is always aligned to at least an 8 byte boundary, or to a
2999 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
3000 ** option is used.
3001 **
3002 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
3003 ** must be either NULL or else pointers obtained from a prior
3004 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
3005 ** not yet been released.
3006 **
3007 ** The application must not read or write any part of
3008 ** a block of memory after it has been released using
3009 ** [sqlite3_free()] or [sqlite3_realloc()].
3010 */
3011 SQLITE_API void *sqlite3_malloc(int);
3012 SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
3013 SQLITE_API void *sqlite3_realloc(void*, int);
3014 SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
3015 SQLITE_API void sqlite3_free(void*);
3016 SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
3017 
3018 /*
3019 ** CAPI3REF: Memory Allocator Statistics
3020 **
3021 ** SQLite provides these two interfaces for reporting on the status
3022 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
3023 ** routines, which form the built-in memory allocation subsystem.
3024 **
3025 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
3026 ** of memory currently outstanding (malloced but not freed).
3027 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
3028 ** value of [sqlite3_memory_used()] since the high-water mark
3029 ** was last reset.  ^The values returned by [sqlite3_memory_used()] and
3030 ** [sqlite3_memory_highwater()] include any overhead
3031 ** added by SQLite in its implementation of [sqlite3_malloc()],
3032 ** but not overhead added by the any underlying system library
3033 ** routines that [sqlite3_malloc()] may call.
3034 **
3035 ** ^The memory high-water mark is reset to the current value of
3036 ** [sqlite3_memory_used()] if and only if the parameter to
3037 ** [sqlite3_memory_highwater()] is true.  ^The value returned
3038 ** by [sqlite3_memory_highwater(1)] is the high-water mark
3039 ** prior to the reset.
3040 */
3041 SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
3042 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
3043 
3044 /*
3045 ** CAPI3REF: Pseudo-Random Number Generator
3046 **
3047 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
3048 ** select random [ROWID | ROWIDs] when inserting new records into a table that
3049 ** already uses the largest possible [ROWID].  The PRNG is also used for
3050 ** the built-in random() and randomblob() SQL functions.  This interface allows
3051 ** applications to access the same PRNG for other purposes.
3052 **
3053 ** ^A call to this routine stores N bytes of randomness into buffer P.
3054 ** ^The P parameter can be a NULL pointer.
3055 **
3056 ** ^If this routine has not been previously called or if the previous
3057 ** call had N less than one or a NULL pointer for P, then the PRNG is
3058 ** seeded using randomness obtained from the xRandomness method of
3059 ** the default [sqlite3_vfs] object.
3060 ** ^If the previous call to this routine had an N of 1 or more and a
3061 ** non-NULL P then the pseudo-randomness is generated
3062 ** internally and without recourse to the [sqlite3_vfs] xRandomness
3063 ** method.
3064 */
3065 SQLITE_API void sqlite3_randomness(int N, void *P);
3066 
3067 /*
3068 ** CAPI3REF: Compile-Time Authorization Callbacks
3069 ** METHOD: sqlite3
3070 ** KEYWORDS: {authorizer callback}
3071 **
3072 ** ^This routine registers an authorizer callback with a particular
3073 ** [database connection], supplied in the first argument.
3074 ** ^The authorizer callback is invoked as SQL statements are being compiled
3075 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
3076 ** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
3077 ** and [sqlite3_prepare16_v3()].  ^At various
3078 ** points during the compilation process, as logic is being created
3079 ** to perform various actions, the authorizer callback is invoked to
3080 ** see if those actions are allowed.  ^The authorizer callback should
3081 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
3082 ** specific action but allow the SQL statement to continue to be
3083 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
3084 ** rejected with an error.  ^If the authorizer callback returns
3085 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
3086 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
3087 ** the authorizer will fail with an error message.
3088 **
3089 ** When the callback returns [SQLITE_OK], that means the operation
3090 ** requested is ok.  ^When the callback returns [SQLITE_DENY], the
3091 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
3092 ** authorizer will fail with an error message explaining that
3093 ** access is denied.
3094 **
3095 ** ^The first parameter to the authorizer callback is a copy of the third
3096 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
3097 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
3098 ** the particular action to be authorized. ^The third through sixth parameters
3099 ** to the callback are either NULL pointers or zero-terminated strings
3100 ** that contain additional details about the action to be authorized.
3101 ** Applications must always be prepared to encounter a NULL pointer in any
3102 ** of the third through the sixth parameters of the authorization callback.
3103 **
3104 ** ^If the action code is [SQLITE_READ]
3105 ** and the callback returns [SQLITE_IGNORE] then the
3106 ** [prepared statement] statement is constructed to substitute
3107 ** a NULL value in place of the table column that would have
3108 ** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
3109 ** return can be used to deny an untrusted user access to individual
3110 ** columns of a table.
3111 ** ^When a table is referenced by a [SELECT] but no column values are
3112 ** extracted from that table (for example in a query like
3113 ** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
3114 ** is invoked once for that table with a column name that is an empty string.
3115 ** ^If the action code is [SQLITE_DELETE] and the callback returns
3116 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
3117 ** [truncate optimization] is disabled and all rows are deleted individually.
3118 **
3119 ** An authorizer is used when [sqlite3_prepare | preparing]
3120 ** SQL statements from an untrusted source, to ensure that the SQL statements
3121 ** do not try to access data they are not allowed to see, or that they do not
3122 ** try to execute malicious statements that damage the database.  For
3123 ** example, an application may allow a user to enter arbitrary
3124 ** SQL queries for evaluation by a database.  But the application does
3125 ** not want the user to be able to make arbitrary changes to the
3126 ** database.  An authorizer could then be put in place while the
3127 ** user-entered SQL is being [sqlite3_prepare | prepared] that
3128 ** disallows everything except [SELECT] statements.
3129 **
3130 ** Applications that need to process SQL from untrusted sources
3131 ** might also consider lowering resource limits using [sqlite3_limit()]
3132 ** and limiting database size using the [max_page_count] [PRAGMA]
3133 ** in addition to using an authorizer.
3134 **
3135 ** ^(Only a single authorizer can be in place on a database connection
3136 ** at a time.  Each call to sqlite3_set_authorizer overrides the
3137 ** previous call.)^  ^Disable the authorizer by installing a NULL callback.
3138 ** The authorizer is disabled by default.
3139 **
3140 ** The authorizer callback must not do anything that will modify
3141 ** the database connection that invoked the authorizer callback.
3142 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3143 ** database connections for the meaning of "modify" in this paragraph.
3144 **
3145 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
3146 ** statement might be re-prepared during [sqlite3_step()] due to a
3147 ** schema change.  Hence, the application should ensure that the
3148 ** correct authorizer callback remains in place during the [sqlite3_step()].
3149 **
3150 ** ^Note that the authorizer callback is invoked only during
3151 ** [sqlite3_prepare()] or its variants.  Authorization is not
3152 ** performed during statement evaluation in [sqlite3_step()], unless
3153 ** as stated in the previous paragraph, sqlite3_step() invokes
3154 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
3155 */
3156 SQLITE_API int sqlite3_set_authorizer(
3157   sqlite3*,
3158   int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
3159   void *pUserData
3160 );
3161 
3162 /*
3163 ** CAPI3REF: Authorizer Return Codes
3164 **
3165 ** The [sqlite3_set_authorizer | authorizer callback function] must
3166 ** return either [SQLITE_OK] or one of these two constants in order
3167 ** to signal SQLite whether or not the action is permitted.  See the
3168 ** [sqlite3_set_authorizer | authorizer documentation] for additional
3169 ** information.
3170 **
3171 ** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
3172 ** returned from the [sqlite3_vtab_on_conflict()] interface.
3173 */
3174 #define SQLITE_DENY   1   /* Abort the SQL statement with an error */
3175 #define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
3176 
3177 /*
3178 ** CAPI3REF: Authorizer Action Codes
3179 **
3180 ** The [sqlite3_set_authorizer()] interface registers a callback function
3181 ** that is invoked to authorize certain SQL statement actions.  The
3182 ** second parameter to the callback is an integer code that specifies
3183 ** what action is being authorized.  These are the integer action codes that
3184 ** the authorizer callback may be passed.
3185 **
3186 ** These action code values signify what kind of operation is to be
3187 ** authorized.  The 3rd and 4th parameters to the authorization
3188 ** callback function will be parameters or NULL depending on which of these
3189 ** codes is used as the second parameter.  ^(The 5th parameter to the
3190 ** authorizer callback is the name of the database ("main", "temp",
3191 ** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
3192 ** is the name of the inner-most trigger or view that is responsible for
3193 ** the access attempt or NULL if this access attempt is directly from
3194 ** top-level SQL code.
3195 */
3196 /******************************************* 3rd ************ 4th ***********/
3197 #define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
3198 #define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
3199 #define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
3200 #define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
3201 #define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
3202 #define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
3203 #define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
3204 #define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
3205 #define SQLITE_DELETE                9   /* Table Name      NULL            */
3206 #define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
3207 #define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
3208 #define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
3209 #define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
3210 #define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
3211 #define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
3212 #define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
3213 #define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
3214 #define SQLITE_INSERT               18   /* Table Name      NULL            */
3215 #define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
3216 #define SQLITE_READ                 20   /* Table Name      Column Name     */
3217 #define SQLITE_SELECT               21   /* NULL            NULL            */
3218 #define SQLITE_TRANSACTION          22   /* Operation       NULL            */
3219 #define SQLITE_UPDATE               23   /* Table Name      Column Name     */
3220 #define SQLITE_ATTACH               24   /* Filename        NULL            */
3221 #define SQLITE_DETACH               25   /* Database Name   NULL            */
3222 #define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
3223 #define SQLITE_REINDEX              27   /* Index Name      NULL            */
3224 #define SQLITE_ANALYZE              28   /* Table Name      NULL            */
3225 #define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
3226 #define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
3227 #define SQLITE_FUNCTION             31   /* NULL            Function Name   */
3228 #define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
3229 #define SQLITE_COPY                  0   /* No longer used */
3230 #define SQLITE_RECURSIVE            33   /* NULL            NULL            */
3231 
3232 /*
3233 ** CAPI3REF: Tracing And Profiling Functions
3234 ** METHOD: sqlite3
3235 **
3236 ** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
3237 ** instead of the routines described here.
3238 **
3239 ** These routines register callback functions that can be used for
3240 ** tracing and profiling the execution of SQL statements.
3241 **
3242 ** ^The callback function registered by sqlite3_trace() is invoked at
3243 ** various times when an SQL statement is being run by [sqlite3_step()].
3244 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
3245 ** SQL statement text as the statement first begins executing.
3246 ** ^(Additional sqlite3_trace() callbacks might occur
3247 ** as each triggered subprogram is entered.  The callbacks for triggers
3248 ** contain a UTF-8 SQL comment that identifies the trigger.)^
3249 **
3250 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
3251 ** the length of [bound parameter] expansion in the output of sqlite3_trace().
3252 **
3253 ** ^The callback function registered by sqlite3_profile() is invoked
3254 ** as each SQL statement finishes.  ^The profile callback contains
3255 ** the original statement text and an estimate of wall-clock time
3256 ** of how long that statement took to run.  ^The profile callback
3257 ** time is in units of nanoseconds, however the current implementation
3258 ** is only capable of millisecond resolution so the six least significant
3259 ** digits in the time are meaningless.  Future versions of SQLite
3260 ** might provide greater resolution on the profiler callback.  Invoking
3261 ** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the
3262 ** profile callback.
3263 */
3264 SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
3265    void(*xTrace)(void*,const char*), void*);
3266 SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
3267    void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
3268 
3269 /*
3270 ** CAPI3REF: SQL Trace Event Codes
3271 ** KEYWORDS: SQLITE_TRACE
3272 **
3273 ** These constants identify classes of events that can be monitored
3274 ** using the [sqlite3_trace_v2()] tracing logic.  The M argument
3275 ** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
3276 ** the following constants.  ^The first argument to the trace callback
3277 ** is one of the following constants.
3278 **
3279 ** New tracing constants may be added in future releases.
3280 **
3281 ** ^A trace callback has four arguments: xCallback(T,C,P,X).
3282 ** ^The T argument is one of the integer type codes above.
3283 ** ^The C argument is a copy of the context pointer passed in as the
3284 ** fourth argument to [sqlite3_trace_v2()].
3285 ** The P and X arguments are pointers whose meanings depend on T.
3286 **
3287 ** <dl>
3288 ** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
3289 ** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
3290 ** first begins running and possibly at other times during the
3291 ** execution of the prepared statement, such as at the start of each
3292 ** trigger subprogram. ^The P argument is a pointer to the
3293 ** [prepared statement]. ^The X argument is a pointer to a string which
3294 ** is the unexpanded SQL text of the prepared statement or an SQL comment
3295 ** that indicates the invocation of a trigger.  ^The callback can compute
3296 ** the same text that would have been returned by the legacy [sqlite3_trace()]
3297 ** interface by using the X argument when X begins with "--" and invoking
3298 ** [sqlite3_expanded_sql(P)] otherwise.
3299 **
3300 ** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
3301 ** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
3302 ** information as is provided by the [sqlite3_profile()] callback.
3303 ** ^The P argument is a pointer to the [prepared statement] and the
3304 ** X argument points to a 64-bit integer which is approximately
3305 ** the number of nanoseconds that the prepared statement took to run.
3306 ** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
3307 **
3308 ** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
3309 ** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
3310 ** statement generates a single row of result.
3311 ** ^The P argument is a pointer to the [prepared statement] and the
3312 ** X argument is unused.
3313 **
3314 ** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
3315 ** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
3316 ** connection closes.
3317 ** ^The P argument is a pointer to the [database connection] object
3318 ** and the X argument is unused.
3319 ** </dl>
3320 */
3321 #define SQLITE_TRACE_STMT       0x01
3322 #define SQLITE_TRACE_PROFILE    0x02
3323 #define SQLITE_TRACE_ROW        0x04
3324 #define SQLITE_TRACE_CLOSE      0x08
3325 
3326 /*
3327 ** CAPI3REF: SQL Trace Hook
3328 ** METHOD: sqlite3
3329 **
3330 ** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
3331 ** function X against [database connection] D, using property mask M
3332 ** and context pointer P.  ^If the X callback is
3333 ** NULL or if the M mask is zero, then tracing is disabled.  The
3334 ** M argument should be the bitwise OR-ed combination of
3335 ** zero or more [SQLITE_TRACE] constants.
3336 **
3337 ** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides
3338 ** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2().
3339 **
3340 ** ^The X callback is invoked whenever any of the events identified by
3341 ** mask M occur.  ^The integer return value from the callback is currently
3342 ** ignored, though this may change in future releases.  Callback
3343 ** implementations should return zero to ensure future compatibility.
3344 **
3345 ** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
3346 ** ^The T argument is one of the [SQLITE_TRACE]
3347 ** constants to indicate why the callback was invoked.
3348 ** ^The C argument is a copy of the context pointer.
3349 ** The P and X arguments are pointers whose meanings depend on T.
3350 **
3351 ** The sqlite3_trace_v2() interface is intended to replace the legacy
3352 ** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
3353 ** are deprecated.
3354 */
3355 SQLITE_API int sqlite3_trace_v2(
3356   sqlite3*,
3357   unsigned uMask,
3358   int(*xCallback)(unsigned,void*,void*,void*),
3359   void *pCtx
3360 );
3361 
3362 /*
3363 ** CAPI3REF: Query Progress Callbacks
3364 ** METHOD: sqlite3
3365 **
3366 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
3367 ** function X to be invoked periodically during long running calls to
3368 ** [sqlite3_step()] and [sqlite3_prepare()] and similar for
3369 ** database connection D.  An example use for this
3370 ** interface is to keep a GUI updated during a large query.
3371 **
3372 ** ^The parameter P is passed through as the only parameter to the
3373 ** callback function X.  ^The parameter N is the approximate number of
3374 ** [virtual machine instructions] that are evaluated between successive
3375 ** invocations of the callback X.  ^If N is less than one then the progress
3376 ** handler is disabled.
3377 **
3378 ** ^Only a single progress handler may be defined at one time per
3379 ** [database connection]; setting a new progress handler cancels the
3380 ** old one.  ^Setting parameter X to NULL disables the progress handler.
3381 ** ^The progress handler is also disabled by setting N to a value less
3382 ** than 1.
3383 **
3384 ** ^If the progress callback returns non-zero, the operation is
3385 ** interrupted.  This feature can be used to implement a
3386 ** "Cancel" button on a GUI progress dialog box.
3387 **
3388 ** The progress handler callback must not do anything that will modify
3389 ** the database connection that invoked the progress handler.
3390 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3391 ** database connections for the meaning of "modify" in this paragraph.
3392 **
3393 ** The progress handler callback would originally only be invoked from the
3394 ** bytecode engine.  It still might be invoked during [sqlite3_prepare()]
3395 ** and similar because those routines might force a reparse of the schema
3396 ** which involves running the bytecode engine.  However, beginning with
3397 ** SQLite version 3.41.0, the progress handler callback might also be
3398 ** invoked directly from [sqlite3_prepare()] while analyzing and generating
3399 ** code for complex queries.
3400 */
3401 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
3402 
3403 /*
3404 ** CAPI3REF: Opening A New Database Connection
3405 ** CONSTRUCTOR: sqlite3
3406 **
3407 ** ^These routines open an SQLite database file as specified by the
3408 ** filename argument. ^The filename argument is interpreted as UTF-8 for
3409 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
3410 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
3411 ** returned in *ppDb, even if an error occurs.  The only exception is that
3412 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
3413 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
3414 ** object.)^ ^(If the database is opened (and/or created) successfully, then
3415 ** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
3416 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
3417 ** an English language description of the error following a failure of any
3418 ** of the sqlite3_open() routines.
3419 **
3420 ** ^The default encoding will be UTF-8 for databases created using
3421 ** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
3422 ** created using sqlite3_open16() will be UTF-16 in the native byte order.
3423 **
3424 ** Whether or not an error occurs when it is opened, resources
3425 ** associated with the [database connection] handle should be released by
3426 ** passing it to [sqlite3_close()] when it is no longer required.
3427 **
3428 ** The sqlite3_open_v2() interface works like sqlite3_open()
3429 ** except that it accepts two additional parameters for additional control
3430 ** over the new database connection.  ^(The flags parameter to
3431 ** sqlite3_open_v2() must include, at a minimum, one of the following
3432 ** three flag combinations:)^
3433 **
3434 ** <dl>
3435 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
3436 ** <dd>The database is opened in read-only mode.  If the database does
3437 ** not already exist, an error is returned.</dd>)^
3438 **
3439 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
3440 ** <dd>The database is opened for reading and writing if possible, or
3441 ** reading only if the file is write protected by the operating
3442 ** system.  In either case the database must already exist, otherwise
3443 ** an error is returned.  For historical reasons, if opening in
3444 ** read-write mode fails due to OS-level permissions, an attempt is
3445 ** made to open it in read-only mode. [sqlite3_db_readonly()] can be
3446 ** used to determine whether the database is actually
3447 ** read-write.</dd>)^
3448 **
3449 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
3450 ** <dd>The database is opened for reading and writing, and is created if
3451 ** it does not already exist. This is the behavior that is always used for
3452 ** sqlite3_open() and sqlite3_open16().</dd>)^
3453 ** </dl>
3454 **
3455 ** In addition to the required flags, the following optional flags are
3456 ** also supported:
3457 **
3458 ** <dl>
3459 ** ^(<dt>[SQLITE_OPEN_URI]</dt>
3460 ** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^
3461 **
3462 ** ^(<dt>[SQLITE_OPEN_MEMORY]</dt>
3463 ** <dd>The database will be opened as an in-memory database.  The database
3464 ** is named by the "filename" argument for the purposes of cache-sharing,
3465 ** if shared cache mode is enabled, but the "filename" is otherwise ignored.
3466 ** </dd>)^
3467 **
3468 ** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt>
3469 ** <dd>The new database connection will use the "multi-thread"
3470 ** [threading mode].)^  This means that separate threads are allowed
3471 ** to use SQLite at the same time, as long as each thread is using
3472 ** a different [database connection].
3473 **
3474 ** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt>
3475 ** <dd>The new database connection will use the "serialized"
3476 ** [threading mode].)^  This means the multiple threads can safely
3477 ** attempt to use the same database connection at the same time.
3478 ** (Mutexes will block any actual concurrency, but in this mode
3479 ** there is no harm in trying.)
3480 **
3481 ** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt>
3482 ** <dd>The database is opened [shared cache] enabled, overriding
3483 ** the default shared cache setting provided by
3484 ** [sqlite3_enable_shared_cache()].)^
3485 ** The [use of shared cache mode is discouraged] and hence shared cache
3486 ** capabilities may be omitted from many builds of SQLite.  In such cases,
3487 ** this option is a no-op.
3488 **
3489 ** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt>
3490 ** <dd>The database is opened [shared cache] disabled, overriding
3491 ** the default shared cache setting provided by
3492 ** [sqlite3_enable_shared_cache()].)^
3493 **
3494 ** [[OPEN_EXRESCODE]] ^(<dt>[SQLITE_OPEN_EXRESCODE]</dt>
3495 ** <dd>The database connection comes up in "extended result code mode".
3496 ** In other words, the database behaves has if
3497 ** [sqlite3_extended_result_codes(db,1)] where called on the database
3498 ** connection as soon as the connection is created. In addition to setting
3499 ** the extended result code mode, this flag also causes [sqlite3_open_v2()]
3500 ** to return an extended result code.</dd>
3501 **
3502 ** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt>
3503 ** <dd>The database filename is not allowed to contain a symbolic link</dd>
3504 ** </dl>)^
3505 **
3506 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
3507 ** required combinations shown above optionally combined with other
3508 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
3509 ** then the behavior is undefined.  Historic versions of SQLite
3510 ** have silently ignored surplus bits in the flags parameter to
3511 ** sqlite3_open_v2(), however that behavior might not be carried through
3512 ** into future versions of SQLite and so applications should not rely
3513 ** upon it.  Note in particular that the SQLITE_OPEN_EXCLUSIVE flag is a no-op
3514 ** for sqlite3_open_v2().  The SQLITE_OPEN_EXCLUSIVE does *not* cause
3515 ** the open to fail if the database already exists.  The SQLITE_OPEN_EXCLUSIVE
3516 ** flag is intended for use by the [sqlite3_vfs|VFS interface] only, and not
3517 ** by sqlite3_open_v2().
3518 **
3519 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
3520 ** [sqlite3_vfs] object that defines the operating system interface that
3521 ** the new database connection should use.  ^If the fourth parameter is
3522 ** a NULL pointer then the default [sqlite3_vfs] object is used.
3523 **
3524 ** ^If the filename is ":memory:", then a private, temporary in-memory database
3525 ** is created for the connection.  ^This in-memory database will vanish when
3526 ** the database connection is closed.  Future versions of SQLite might
3527 ** make use of additional special filenames that begin with the ":" character.
3528 ** It is recommended that when a database filename actually does begin with
3529 ** a ":" character you should prefix the filename with a pathname such as
3530 ** "./" to avoid ambiguity.
3531 **
3532 ** ^If the filename is an empty string, then a private, temporary
3533 ** on-disk database will be created.  ^This private database will be
3534 ** automatically deleted as soon as the database connection is closed.
3535 **
3536 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
3537 **
3538 ** ^If [URI filename] interpretation is enabled, and the filename argument
3539 ** begins with "file:", then the filename is interpreted as a URI. ^URI
3540 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
3541 ** set in the third argument to sqlite3_open_v2(), or if it has
3542 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
3543 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
3544 ** URI filename interpretation is turned off
3545 ** by default, but future releases of SQLite might enable URI filename
3546 ** interpretation by default.  See "[URI filenames]" for additional
3547 ** information.
3548 **
3549 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
3550 ** authority, then it must be either an empty string or the string
3551 ** "localhost". ^If the authority is not an empty string or "localhost", an
3552 ** error is returned to the caller. ^The fragment component of a URI, if
3553 ** present, is ignored.
3554 **
3555 ** ^SQLite uses the path component of the URI as the name of the disk file
3556 ** which contains the database. ^If the path begins with a '/' character,
3557 ** then it is interpreted as an absolute path. ^If the path does not begin
3558 ** with a '/' (meaning that the authority section is omitted from the URI)
3559 ** then the path is interpreted as a relative path.
3560 ** ^(On windows, the first component of an absolute path
3561 ** is a drive specification (e.g. "C:").)^
3562 **
3563 ** [[core URI query parameters]]
3564 ** The query component of a URI may contain parameters that are interpreted
3565 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
3566 ** SQLite and its built-in [VFSes] interpret the
3567 ** following query parameters:
3568 **
3569 ** <ul>
3570 **   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
3571 **     a VFS object that provides the operating system interface that should
3572 **     be used to access the database file on disk. ^If this option is set to
3573 **     an empty string the default VFS object is used. ^Specifying an unknown
3574 **     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
3575 **     present, then the VFS specified by the option takes precedence over
3576 **     the value passed as the fourth parameter to sqlite3_open_v2().
3577 **
3578 **   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
3579 **     "rwc", or "memory". Attempting to set it to any other value is
3580 **     an error)^.
3581 **     ^If "ro" is specified, then the database is opened for read-only
3582 **     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
3583 **     third argument to sqlite3_open_v2(). ^If the mode option is set to
3584 **     "rw", then the database is opened for read-write (but not create)
3585 **     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
3586 **     been set. ^Value "rwc" is equivalent to setting both
3587 **     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
3588 **     set to "memory" then a pure [in-memory database] that never reads
3589 **     or writes from disk is used. ^It is an error to specify a value for
3590 **     the mode parameter that is less restrictive than that specified by
3591 **     the flags passed in the third parameter to sqlite3_open_v2().
3592 **
3593 **   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
3594 **     "private". ^Setting it to "shared" is equivalent to setting the
3595 **     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
3596 **     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
3597 **     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
3598 **     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
3599 **     a URI filename, its value overrides any behavior requested by setting
3600 **     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
3601 **
3602 **  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
3603 **     [powersafe overwrite] property does or does not apply to the
3604 **     storage media on which the database file resides.
3605 **
3606 **  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
3607 **     which if set disables file locking in rollback journal modes.  This
3608 **     is useful for accessing a database on a filesystem that does not
3609 **     support locking.  Caution:  Database corruption might result if two
3610 **     or more processes write to the same database and any one of those
3611 **     processes uses nolock=1.
3612 **
3613 **  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
3614 **     parameter that indicates that the database file is stored on
3615 **     read-only media.  ^When immutable is set, SQLite assumes that the
3616 **     database file cannot be changed, even by a process with higher
3617 **     privilege, and so the database is opened read-only and all locking
3618 **     and change detection is disabled.  Caution: Setting the immutable
3619 **     property on a database file that does in fact change can result
3620 **     in incorrect query results and/or [SQLITE_CORRUPT] errors.
3621 **     See also: [SQLITE_IOCAP_IMMUTABLE].
3622 **
3623 ** </ul>
3624 **
3625 ** ^Specifying an unknown parameter in the query component of a URI is not an
3626 ** error.  Future versions of SQLite might understand additional query
3627 ** parameters.  See "[query parameters with special meaning to SQLite]" for
3628 ** additional information.
3629 **
3630 ** [[URI filename examples]] <h3>URI filename examples</h3>
3631 **
3632 ** <table border="1" align=center cellpadding=5>
3633 ** <tr><th> URI filenames <th> Results
3634 ** <tr><td> file:data.db <td>
3635 **          Open the file "data.db" in the current directory.
3636 ** <tr><td> file:/home/fred/data.db<br>
3637 **          file:///home/fred/data.db <br>
3638 **          file://localhost/home/fred/data.db <br> <td>
3639 **          Open the database file "/home/fred/data.db".
3640 ** <tr><td> file://darkstar/home/fred/data.db <td>
3641 **          An error. "darkstar" is not a recognized authority.
3642 ** <tr><td style="white-space:nowrap">
3643 **          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
3644 **     <td> Windows only: Open the file "data.db" on fred's desktop on drive
3645 **          C:. Note that the %20 escaping in this example is not strictly
3646 **          necessary - space characters can be used literally
3647 **          in URI filenames.
3648 ** <tr><td> file:data.db?mode=ro&cache=private <td>
3649 **          Open file "data.db" in the current directory for read-only access.
3650 **          Regardless of whether or not shared-cache mode is enabled by
3651 **          default, use a private cache.
3652 ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
3653 **          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
3654 **          that uses dot-files in place of posix advisory locking.
3655 ** <tr><td> file:data.db?mode=readonly <td>
3656 **          An error. "readonly" is not a valid option for the "mode" parameter.
3657 **          Use "ro" instead:  "file:data.db?mode=ro".
3658 ** </table>
3659 **
3660 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
3661 ** query components of a URI. A hexadecimal escape sequence consists of a
3662 ** percent sign - "%" - followed by exactly two hexadecimal digits
3663 ** specifying an octet value. ^Before the path or query components of a
3664 ** URI filename are interpreted, they are encoded using UTF-8 and all
3665 ** hexadecimal escape sequences replaced by a single byte containing the
3666 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
3667 ** the results are undefined.
3668 **
3669 ** <b>Note to Windows users:</b>  The encoding used for the filename argument
3670 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
3671 ** codepage is currently defined.  Filenames containing international
3672 ** characters must be converted to UTF-8 prior to passing them into
3673 ** sqlite3_open() or sqlite3_open_v2().
3674 **
3675 ** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
3676 ** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
3677 ** features that require the use of temporary files may fail.
3678 **
3679 ** See also: [sqlite3_temp_directory]
3680 */
3681 SQLITE_API int sqlite3_open(
3682   const char *filename,   /* Database filename (UTF-8) */
3683   sqlite3 **ppDb          /* OUT: SQLite db handle */
3684 );
3685 SQLITE_API int sqlite3_open16(
3686   const void *filename,   /* Database filename (UTF-16) */
3687   sqlite3 **ppDb          /* OUT: SQLite db handle */
3688 );
3689 SQLITE_API int sqlite3_open_v2(
3690   const char *filename,   /* Database filename (UTF-8) */
3691   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3692   int flags,              /* Flags */
3693   const char *zVfs        /* Name of VFS module to use */
3694 );
3695 
3696 /*
3697 ** CAPI3REF: Obtain Values For URI Parameters
3698 **
3699 ** These are utility routines, useful to [VFS|custom VFS implementations],
3700 ** that check if a database file was a URI that contained a specific query
3701 ** parameter, and if so obtains the value of that query parameter.
3702 **
3703 ** The first parameter to these interfaces (hereafter referred to
3704 ** as F) must be one of:
3705 ** <ul>
3706 ** <li> A database filename pointer created by the SQLite core and
3707 ** passed into the xOpen() method of a VFS implemention, or
3708 ** <li> A filename obtained from [sqlite3_db_filename()], or
3709 ** <li> A new filename constructed using [sqlite3_create_filename()].
3710 ** </ul>
3711 ** If the F parameter is not one of the above, then the behavior is
3712 ** undefined and probably undesirable.  Older versions of SQLite were
3713 ** more tolerant of invalid F parameters than newer versions.
3714 **
3715 ** If F is a suitable filename (as described in the previous paragraph)
3716 ** and if P is the name of the query parameter, then
3717 ** sqlite3_uri_parameter(F,P) returns the value of the P
3718 ** parameter if it exists or a NULL pointer if P does not appear as a
3719 ** query parameter on F.  If P is a query parameter of F and it
3720 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3721 ** a pointer to an empty string.
3722 **
3723 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3724 ** parameter and returns true (1) or false (0) according to the value
3725 ** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3726 ** value of query parameter P is one of "yes", "true", or "on" in any
3727 ** case or if the value begins with a non-zero number.  The
3728 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3729 ** query parameter P is one of "no", "false", or "off" in any case or
3730 ** if the value begins with a numeric zero.  If P is not a query
3731 ** parameter on F or if the value of P does not match any of the
3732 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3733 **
3734 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3735 ** 64-bit signed integer and returns that integer, or D if P does not
3736 ** exist.  If the value of P is something other than an integer, then
3737 ** zero is returned.
3738 **
3739 ** The sqlite3_uri_key(F,N) returns a pointer to the name (not
3740 ** the value) of the N-th query parameter for filename F, or a NULL
3741 ** pointer if N is less than zero or greater than the number of query
3742 ** parameters minus 1.  The N value is zero-based so N should be 0 to obtain
3743 ** the name of the first query parameter, 1 for the second parameter, and
3744 ** so forth.
3745 **
3746 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3747 ** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
3748 ** is not a database file pathname pointer that the SQLite core passed
3749 ** into the xOpen VFS method, then the behavior of this routine is undefined
3750 ** and probably undesirable.
3751 **
3752 ** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F
3753 ** parameter can also be the name of a rollback journal file or WAL file
3754 ** in addition to the main database file.  Prior to version 3.31.0, these
3755 ** routines would only work if F was the name of the main database file.
3756 ** When the F parameter is the name of the rollback journal or WAL file,
3757 ** it has access to all the same query parameters as were found on the
3758 ** main database file.
3759 **
3760 ** See the [URI filename] documentation for additional information.
3761 */
3762 SQLITE_API const char *sqlite3_uri_parameter(sqlite3_filename z, const char *zParam);
3763 SQLITE_API int sqlite3_uri_boolean(sqlite3_filename z, const char *zParam, int bDefault);
3764 SQLITE_API sqlite3_int64 sqlite3_uri_int64(sqlite3_filename, const char*, sqlite3_int64);
3765 SQLITE_API const char *sqlite3_uri_key(sqlite3_filename z, int N);
3766 
3767 /*
3768 ** CAPI3REF:  Translate filenames
3769 **
3770 ** These routines are available to [VFS|custom VFS implementations] for
3771 ** translating filenames between the main database file, the journal file,
3772 ** and the WAL file.
3773 **
3774 ** If F is the name of an sqlite database file, journal file, or WAL file
3775 ** passed by the SQLite core into the VFS, then sqlite3_filename_database(F)
3776 ** returns the name of the corresponding database file.
3777 **
3778 ** If F is the name of an sqlite database file, journal file, or WAL file
3779 ** passed by the SQLite core into the VFS, or if F is a database filename
3780 ** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F)
3781 ** returns the name of the corresponding rollback journal file.
3782 **
3783 ** If F is the name of an sqlite database file, journal file, or WAL file
3784 ** that was passed by the SQLite core into the VFS, or if F is a database
3785 ** filename obtained from [sqlite3_db_filename()], then
3786 ** sqlite3_filename_wal(F) returns the name of the corresponding
3787 ** WAL file.
3788 **
3789 ** In all of the above, if F is not the name of a database, journal or WAL
3790 ** filename passed into the VFS from the SQLite core and F is not the
3791 ** return value from [sqlite3_db_filename()], then the result is
3792 ** undefined and is likely a memory access violation.
3793 */
3794 SQLITE_API const char *sqlite3_filename_database(sqlite3_filename);
3795 SQLITE_API const char *sqlite3_filename_journal(sqlite3_filename);
3796 SQLITE_API const char *sqlite3_filename_wal(sqlite3_filename);
3797 
3798 /*
3799 ** CAPI3REF:  Database File Corresponding To A Journal
3800 **
3801 ** ^If X is the name of a rollback or WAL-mode journal file that is
3802 ** passed into the xOpen method of [sqlite3_vfs], then
3803 ** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file]
3804 ** object that represents the main database file.
3805 **
3806 ** This routine is intended for use in custom [VFS] implementations
3807 ** only.  It is not a general-purpose interface.
3808 ** The argument sqlite3_file_object(X) must be a filename pointer that
3809 ** has been passed into [sqlite3_vfs].xOpen method where the
3810 ** flags parameter to xOpen contains one of the bits
3811 ** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL].  Any other use
3812 ** of this routine results in undefined and probably undesirable
3813 ** behavior.
3814 */
3815 SQLITE_API sqlite3_file *sqlite3_database_file_object(const char*);
3816 
3817 /*
3818 ** CAPI3REF: Create and Destroy VFS Filenames
3819 **
3820 ** These interfces are provided for use by [VFS shim] implementations and
3821 ** are not useful outside of that context.
3822 **
3823 ** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of
3824 ** database filename D with corresponding journal file J and WAL file W and
3825 ** with N URI parameters key/values pairs in the array P.  The result from
3826 ** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that
3827 ** is safe to pass to routines like:
3828 ** <ul>
3829 ** <li> [sqlite3_uri_parameter()],
3830 ** <li> [sqlite3_uri_boolean()],
3831 ** <li> [sqlite3_uri_int64()],
3832 ** <li> [sqlite3_uri_key()],
3833 ** <li> [sqlite3_filename_database()],
3834 ** <li> [sqlite3_filename_journal()], or
3835 ** <li> [sqlite3_filename_wal()].
3836 ** </ul>
3837 ** If a memory allocation error occurs, sqlite3_create_filename() might
3838 ** return a NULL pointer.  The memory obtained from sqlite3_create_filename(X)
3839 ** must be released by a corresponding call to sqlite3_free_filename(Y).
3840 **
3841 ** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array
3842 ** of 2*N pointers to strings.  Each pair of pointers in this array corresponds
3843 ** to a key and value for a query parameter.  The P parameter may be a NULL
3844 ** pointer if N is zero.  None of the 2*N pointers in the P array may be
3845 ** NULL pointers and key pointers should not be empty strings.
3846 ** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may
3847 ** be NULL pointers, though they can be empty strings.
3848 **
3849 ** The sqlite3_free_filename(Y) routine releases a memory allocation
3850 ** previously obtained from sqlite3_create_filename().  Invoking
3851 ** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op.
3852 **
3853 ** If the Y parameter to sqlite3_free_filename(Y) is anything other
3854 ** than a NULL pointer or a pointer previously acquired from
3855 ** sqlite3_create_filename(), then bad things such as heap
3856 ** corruption or segfaults may occur. The value Y should not be
3857 ** used again after sqlite3_free_filename(Y) has been called.  This means
3858 ** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y,
3859 ** then the corresponding [sqlite3_module.xClose() method should also be
3860 ** invoked prior to calling sqlite3_free_filename(Y).
3861 */
3862 SQLITE_API sqlite3_filename sqlite3_create_filename(
3863   const char *zDatabase,
3864   const char *zJournal,
3865   const char *zWal,
3866   int nParam,
3867   const char **azParam
3868 );
3869 SQLITE_API void sqlite3_free_filename(sqlite3_filename);
3870 
3871 /*
3872 ** CAPI3REF: Error Codes And Messages
3873 ** METHOD: sqlite3
3874 **
3875 ** ^If the most recent sqlite3_* API call associated with
3876 ** [database connection] D failed, then the sqlite3_errcode(D) interface
3877 ** returns the numeric [result code] or [extended result code] for that
3878 ** API call.
3879 ** ^The sqlite3_extended_errcode()
3880 ** interface is the same except that it always returns the
3881 ** [extended result code] even when extended result codes are
3882 ** disabled.
3883 **
3884 ** The values returned by sqlite3_errcode() and/or
3885 ** sqlite3_extended_errcode() might change with each API call.
3886 ** Except, there are some interfaces that are guaranteed to never
3887 ** change the value of the error code.  The error-code preserving
3888 ** interfaces include the following:
3889 **
3890 ** <ul>
3891 ** <li> sqlite3_errcode()
3892 ** <li> sqlite3_extended_errcode()
3893 ** <li> sqlite3_errmsg()
3894 ** <li> sqlite3_errmsg16()
3895 ** <li> sqlite3_error_offset()
3896 ** </ul>
3897 **
3898 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3899 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
3900 ** ^(Memory to hold the error message string is managed internally.
3901 ** The application does not need to worry about freeing the result.
3902 ** However, the error string might be overwritten or deallocated by
3903 ** subsequent calls to other SQLite interface functions.)^
3904 **
3905 ** ^The sqlite3_errstr() interface returns the English-language text
3906 ** that describes the [result code], as UTF-8.
3907 ** ^(Memory to hold the error message string is managed internally
3908 ** and must not be freed by the application)^.
3909 **
3910 ** ^If the most recent error references a specific token in the input
3911 ** SQL, the sqlite3_error_offset() interface returns the byte offset
3912 ** of the start of that token.  ^The byte offset returned by
3913 ** sqlite3_error_offset() assumes that the input SQL is UTF8.
3914 ** ^If the most recent error does not reference a specific token in the input
3915 ** SQL, then the sqlite3_error_offset() function returns -1.
3916 **
3917 ** When the serialized [threading mode] is in use, it might be the
3918 ** case that a second error occurs on a separate thread in between
3919 ** the time of the first error and the call to these interfaces.
3920 ** When that happens, the second error will be reported since these
3921 ** interfaces always report the most recent result.  To avoid
3922 ** this, each thread can obtain exclusive use of the [database connection] D
3923 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3924 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3925 ** all calls to the interfaces listed here are completed.
3926 **
3927 ** If an interface fails with SQLITE_MISUSE, that means the interface
3928 ** was invoked incorrectly by the application.  In that case, the
3929 ** error code and message may or may not be set.
3930 */
3931 SQLITE_API int sqlite3_errcode(sqlite3 *db);
3932 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
3933 SQLITE_API const char *sqlite3_errmsg(sqlite3*);
3934 SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
3935 SQLITE_API const char *sqlite3_errstr(int);
3936 SQLITE_API int sqlite3_error_offset(sqlite3 *db);
3937 
3938 /*
3939 ** CAPI3REF: Prepared Statement Object
3940 ** KEYWORDS: {prepared statement} {prepared statements}
3941 **
3942 ** An instance of this object represents a single SQL statement that
3943 ** has been compiled into binary form and is ready to be evaluated.
3944 **
3945 ** Think of each SQL statement as a separate computer program.  The
3946 ** original SQL text is source code.  A prepared statement object
3947 ** is the compiled object code.  All SQL must be converted into a
3948 ** prepared statement before it can be run.
3949 **
3950 ** The life-cycle of a prepared statement object usually goes like this:
3951 **
3952 ** <ol>
3953 ** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
3954 ** <li> Bind values to [parameters] using the sqlite3_bind_*()
3955 **      interfaces.
3956 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3957 ** <li> Reset the prepared statement using [sqlite3_reset()] then go back
3958 **      to step 2.  Do this zero or more times.
3959 ** <li> Destroy the object using [sqlite3_finalize()].
3960 ** </ol>
3961 */
3962 typedef struct sqlite3_stmt sqlite3_stmt;
3963 
3964 /*
3965 ** CAPI3REF: Run-time Limits
3966 ** METHOD: sqlite3
3967 **
3968 ** ^(This interface allows the size of various constructs to be limited
3969 ** on a connection by connection basis.  The first parameter is the
3970 ** [database connection] whose limit is to be set or queried.  The
3971 ** second parameter is one of the [limit categories] that define a
3972 ** class of constructs to be size limited.  The third parameter is the
3973 ** new limit for that construct.)^
3974 **
3975 ** ^If the new limit is a negative number, the limit is unchanged.
3976 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3977 ** [limits | hard upper bound]
3978 ** set at compile-time by a C preprocessor macro called
3979 ** [limits | SQLITE_MAX_<i>NAME</i>].
3980 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3981 ** ^Attempts to increase a limit above its hard upper bound are
3982 ** silently truncated to the hard upper bound.
3983 **
3984 ** ^Regardless of whether or not the limit was changed, the
3985 ** [sqlite3_limit()] interface returns the prior value of the limit.
3986 ** ^Hence, to find the current value of a limit without changing it,
3987 ** simply invoke this interface with the third parameter set to -1.
3988 **
3989 ** Run-time limits are intended for use in applications that manage
3990 ** both their own internal database and also databases that are controlled
3991 ** by untrusted external sources.  An example application might be a
3992 ** web browser that has its own databases for storing history and
3993 ** separate databases controlled by JavaScript applications downloaded
3994 ** off the Internet.  The internal databases can be given the
3995 ** large, default limits.  Databases managed by external sources can
3996 ** be given much smaller limits designed to prevent a denial of service
3997 ** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
3998 ** interface to further control untrusted SQL.  The size of the database
3999 ** created by an untrusted script can be contained using the
4000 ** [max_page_count] [PRAGMA].
4001 **
4002 ** New run-time limit categories may be added in future releases.
4003 */
4004 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
4005 
4006 /*
4007 ** CAPI3REF: Run-Time Limit Categories
4008 ** KEYWORDS: {limit category} {*limit categories}
4009 **
4010 ** These constants define various performance limits
4011 ** that can be lowered at run-time using [sqlite3_limit()].
4012 ** The synopsis of the meanings of the various limits is shown below.
4013 ** Additional information is available at [limits | Limits in SQLite].
4014 **
4015 ** <dl>
4016 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
4017 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
4018 **
4019 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
4020 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
4021 **
4022 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
4023 ** <dd>The maximum number of columns in a table definition or in the
4024 ** result set of a [SELECT] or the maximum number of columns in an index
4025 ** or in an ORDER BY or GROUP BY clause.</dd>)^
4026 **
4027 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
4028 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
4029 **
4030 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
4031 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
4032 **
4033 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
4034 ** <dd>The maximum number of instructions in a virtual machine program
4035 ** used to implement an SQL statement.  If [sqlite3_prepare_v2()] or
4036 ** the equivalent tries to allocate space for more than this many opcodes
4037 ** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
4038 **
4039 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
4040 ** <dd>The maximum number of arguments on a function.</dd>)^
4041 **
4042 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
4043 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
4044 **
4045 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
4046 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
4047 ** <dd>The maximum length of the pattern argument to the [LIKE] or
4048 ** [GLOB] operators.</dd>)^
4049 **
4050 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
4051 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
4052 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
4053 **
4054 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
4055 ** <dd>The maximum depth of recursion for triggers.</dd>)^
4056 **
4057 ** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
4058 ** <dd>The maximum number of auxiliary worker threads that a single
4059 ** [prepared statement] may start.</dd>)^
4060 ** </dl>
4061 */
4062 #define SQLITE_LIMIT_LENGTH                    0
4063 #define SQLITE_LIMIT_SQL_LENGTH                1
4064 #define SQLITE_LIMIT_COLUMN                    2
4065 #define SQLITE_LIMIT_EXPR_DEPTH                3
4066 #define SQLITE_LIMIT_COMPOUND_SELECT           4
4067 #define SQLITE_LIMIT_VDBE_OP                   5
4068 #define SQLITE_LIMIT_FUNCTION_ARG              6
4069 #define SQLITE_LIMIT_ATTACHED                  7
4070 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
4071 #define SQLITE_LIMIT_VARIABLE_NUMBER           9
4072 #define SQLITE_LIMIT_TRIGGER_DEPTH            10
4073 #define SQLITE_LIMIT_WORKER_THREADS           11
4074 
4075 /*
4076 ** CAPI3REF: Prepare Flags
4077 **
4078 ** These constants define various flags that can be passed into
4079 ** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
4080 ** [sqlite3_prepare16_v3()] interfaces.
4081 **
4082 ** New flags may be added in future releases of SQLite.
4083 **
4084 ** <dl>
4085 ** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
4086 ** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
4087 ** that the prepared statement will be retained for a long time and
4088 ** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
4089 ** and [sqlite3_prepare16_v3()] assume that the prepared statement will
4090 ** be used just once or at most a few times and then destroyed using
4091 ** [sqlite3_finalize()] relatively soon. The current implementation acts
4092 ** on this hint by avoiding the use of [lookaside memory] so as not to
4093 ** deplete the limited store of lookaside memory. Future versions of
4094 ** SQLite may act on this hint differently.
4095 **
4096 ** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt>
4097 ** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
4098 ** to be required for any prepared statement that wanted to use the
4099 ** [sqlite3_normalized_sql()] interface.  However, the
4100 ** [sqlite3_normalized_sql()] interface is now available to all
4101 ** prepared statements, regardless of whether or not they use this
4102 ** flag.
4103 **
4104 ** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt>
4105 ** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
4106 ** to return an error (error code SQLITE_ERROR) if the statement uses
4107 ** any virtual tables.
4108 ** </dl>
4109 */
4110 #define SQLITE_PREPARE_PERSISTENT              0x01
4111 #define SQLITE_PREPARE_NORMALIZE               0x02
4112 #define SQLITE_PREPARE_NO_VTAB                 0x04
4113 
4114 /*
4115 ** CAPI3REF: Compiling An SQL Statement
4116 ** KEYWORDS: {SQL statement compiler}
4117 ** METHOD: sqlite3
4118 ** CONSTRUCTOR: sqlite3_stmt
4119 **
4120 ** To execute an SQL statement, it must first be compiled into a byte-code
4121 ** program using one of these routines.  Or, in other words, these routines
4122 ** are constructors for the [prepared statement] object.
4123 **
4124 ** The preferred routine to use is [sqlite3_prepare_v2()].  The
4125 ** [sqlite3_prepare()] interface is legacy and should be avoided.
4126 ** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
4127 ** for special purposes.
4128 **
4129 ** The use of the UTF-8 interfaces is preferred, as SQLite currently
4130 ** does all parsing using UTF-8.  The UTF-16 interfaces are provided
4131 ** as a convenience.  The UTF-16 interfaces work by converting the
4132 ** input text into UTF-8, then invoking the corresponding UTF-8 interface.
4133 **
4134 ** The first argument, "db", is a [database connection] obtained from a
4135 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
4136 ** [sqlite3_open16()].  The database connection must not have been closed.
4137 **
4138 ** The second argument, "zSql", is the statement to be compiled, encoded
4139 ** as either UTF-8 or UTF-16.  The sqlite3_prepare(), sqlite3_prepare_v2(),
4140 ** and sqlite3_prepare_v3()
4141 ** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
4142 ** and sqlite3_prepare16_v3() use UTF-16.
4143 **
4144 ** ^If the nByte argument is negative, then zSql is read up to the
4145 ** first zero terminator. ^If nByte is positive, then it is the
4146 ** number of bytes read from zSql.  ^If nByte is zero, then no prepared
4147 ** statement is generated.
4148 ** If the caller knows that the supplied string is nul-terminated, then
4149 ** there is a small performance advantage to passing an nByte parameter that
4150 ** is the number of bytes in the input string <i>including</i>
4151 ** the nul-terminator.
4152 **
4153 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
4154 ** past the end of the first SQL statement in zSql.  These routines only
4155 ** compile the first statement in zSql, so *pzTail is left pointing to
4156 ** what remains uncompiled.
4157 **
4158 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
4159 ** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
4160 ** to NULL.  ^If the input text contains no SQL (if the input is an empty
4161 ** string or a comment) then *ppStmt is set to NULL.
4162 ** The calling procedure is responsible for deleting the compiled
4163 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
4164 ** ppStmt may not be NULL.
4165 **
4166 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
4167 ** otherwise an [error code] is returned.
4168 **
4169 ** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
4170 ** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
4171 ** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
4172 ** are retained for backwards compatibility, but their use is discouraged.
4173 ** ^In the "vX" interfaces, the prepared statement
4174 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
4175 ** original SQL text. This causes the [sqlite3_step()] interface to
4176 ** behave differently in three ways:
4177 **
4178 ** <ol>
4179 ** <li>
4180 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
4181 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
4182 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
4183 ** retries will occur before sqlite3_step() gives up and returns an error.
4184 ** </li>
4185 **
4186 ** <li>
4187 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
4188 ** [error codes] or [extended error codes].  ^The legacy behavior was that
4189 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
4190 ** and the application would have to make a second call to [sqlite3_reset()]
4191 ** in order to find the underlying cause of the problem. With the "v2" prepare
4192 ** interfaces, the underlying reason for the error is returned immediately.
4193 ** </li>
4194 **
4195 ** <li>
4196 ** ^If the specific value bound to a [parameter | host parameter] in the
4197 ** WHERE clause might influence the choice of query plan for a statement,
4198 ** then the statement will be automatically recompiled, as if there had been
4199 ** a schema change, on the first [sqlite3_step()] call following any change
4200 ** to the [sqlite3_bind_text | bindings] of that [parameter].
4201 ** ^The specific value of a WHERE-clause [parameter] might influence the
4202 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
4203 ** or [GLOB] operator or if the parameter is compared to an indexed column
4204 ** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled.
4205 ** </li>
4206 ** </ol>
4207 **
4208 ** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
4209 ** the extra prepFlags parameter, which is a bit array consisting of zero or
4210 ** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags.  ^The
4211 ** sqlite3_prepare_v2() interface works exactly the same as
4212 ** sqlite3_prepare_v3() with a zero prepFlags parameter.
4213 */
4214 SQLITE_API int sqlite3_prepare(
4215   sqlite3 *db,            /* Database handle */
4216   const char *zSql,       /* SQL statement, UTF-8 encoded */
4217   int nByte,              /* Maximum length of zSql in bytes. */
4218   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4219   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
4220 );
4221 SQLITE_API int sqlite3_prepare_v2(
4222   sqlite3 *db,            /* Database handle */
4223   const char *zSql,       /* SQL statement, UTF-8 encoded */
4224   int nByte,              /* Maximum length of zSql in bytes. */
4225   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4226   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
4227 );
4228 SQLITE_API int sqlite3_prepare_v3(
4229   sqlite3 *db,            /* Database handle */
4230   const char *zSql,       /* SQL statement, UTF-8 encoded */
4231   int nByte,              /* Maximum length of zSql in bytes. */
4232   unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
4233   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4234   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
4235 );
4236 SQLITE_API int sqlite3_prepare16(
4237   sqlite3 *db,            /* Database handle */
4238   const void *zSql,       /* SQL statement, UTF-16 encoded */
4239   int nByte,              /* Maximum length of zSql in bytes. */
4240   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4241   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
4242 );
4243 SQLITE_API int sqlite3_prepare16_v2(
4244   sqlite3 *db,            /* Database handle */
4245   const void *zSql,       /* SQL statement, UTF-16 encoded */
4246   int nByte,              /* Maximum length of zSql in bytes. */
4247   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4248   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
4249 );
4250 SQLITE_API int sqlite3_prepare16_v3(
4251   sqlite3 *db,            /* Database handle */
4252   const void *zSql,       /* SQL statement, UTF-16 encoded */
4253   int nByte,              /* Maximum length of zSql in bytes. */
4254   unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
4255   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4256   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
4257 );
4258 
4259 /*
4260 ** CAPI3REF: Retrieving Statement SQL
4261 ** METHOD: sqlite3_stmt
4262 **
4263 ** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
4264 ** SQL text used to create [prepared statement] P if P was
4265 ** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
4266 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4267 ** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
4268 ** string containing the SQL text of prepared statement P with
4269 ** [bound parameters] expanded.
4270 ** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
4271 ** string containing the normalized SQL text of prepared statement P.  The
4272 ** semantics used to normalize a SQL statement are unspecified and subject
4273 ** to change.  At a minimum, literal values will be replaced with suitable
4274 ** placeholders.
4275 **
4276 ** ^(For example, if a prepared statement is created using the SQL
4277 ** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
4278 ** and parameter :xyz is unbound, then sqlite3_sql() will return
4279 ** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
4280 ** will return "SELECT 2345,NULL".)^
4281 **
4282 ** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
4283 ** is available to hold the result, or if the result would exceed the
4284 ** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
4285 **
4286 ** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
4287 ** bound parameter expansions.  ^The [SQLITE_OMIT_TRACE] compile-time
4288 ** option causes sqlite3_expanded_sql() to always return NULL.
4289 **
4290 ** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
4291 ** are managed by SQLite and are automatically freed when the prepared
4292 ** statement is finalized.
4293 ** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
4294 ** is obtained from [sqlite3_malloc()] and must be freed by the application
4295 ** by passing it to [sqlite3_free()].
4296 **
4297 ** ^The sqlite3_normalized_sql() interface is only available if
4298 ** the [SQLITE_ENABLE_NORMALIZE] compile-time option is defined.
4299 */
4300 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
4301 SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
4302 #ifdef SQLITE_ENABLE_NORMALIZE
4303 SQLITE_API const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
4304 #endif
4305 
4306 /*
4307 ** CAPI3REF: Determine If An SQL Statement Writes The Database
4308 ** METHOD: sqlite3_stmt
4309 **
4310 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
4311 ** and only if the [prepared statement] X makes no direct changes to
4312 ** the content of the database file.
4313 **
4314 ** Note that [application-defined SQL functions] or
4315 ** [virtual tables] might change the database indirectly as a side effect.
4316 ** ^(For example, if an application defines a function "eval()" that
4317 ** calls [sqlite3_exec()], then the following SQL statement would
4318 ** change the database file through side-effects:
4319 **
4320 ** <blockquote><pre>
4321 **    SELECT eval('DELETE FROM t1') FROM t2;
4322 ** </pre></blockquote>
4323 **
4324 ** But because the [SELECT] statement does not change the database file
4325 ** directly, sqlite3_stmt_readonly() would still return true.)^
4326 **
4327 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
4328 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
4329 ** since the statements themselves do not actually modify the database but
4330 ** rather they control the timing of when other statements modify the
4331 ** database.  ^The [ATTACH] and [DETACH] statements also cause
4332 ** sqlite3_stmt_readonly() to return true since, while those statements
4333 ** change the configuration of a database connection, they do not make
4334 ** changes to the content of the database files on disk.
4335 ** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
4336 ** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
4337 ** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
4338 ** sqlite3_stmt_readonly() returns false for those commands.
4339 **
4340 ** ^This routine returns false if there is any possibility that the
4341 ** statement might change the database file.  ^A false return does
4342 ** not guarantee that the statement will change the database file.
4343 ** ^For example, an UPDATE statement might have a WHERE clause that
4344 ** makes it a no-op, but the sqlite3_stmt_readonly() result would still
4345 ** be false.  ^Similarly, a CREATE TABLE IF NOT EXISTS statement is a
4346 ** read-only no-op if the table already exists, but
4347 ** sqlite3_stmt_readonly() still returns false for such a statement.
4348 **
4349 ** ^If prepared statement X is an [EXPLAIN] or [EXPLAIN QUERY PLAN]
4350 ** statement, then sqlite3_stmt_readonly(X) returns the same value as
4351 ** if the EXPLAIN or EXPLAIN QUERY PLAN prefix were omitted.
4352 */
4353 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
4354 
4355 /*
4356 ** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement
4357 ** METHOD: sqlite3_stmt
4358 **
4359 ** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the
4360 ** prepared statement S is an EXPLAIN statement, or 2 if the
4361 ** statement S is an EXPLAIN QUERY PLAN.
4362 ** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is
4363 ** an ordinary statement or a NULL pointer.
4364 */
4365 SQLITE_API int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);
4366 
4367 /*
4368 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
4369 ** METHOD: sqlite3_stmt
4370 **
4371 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
4372 ** [prepared statement] S has been stepped at least once using
4373 ** [sqlite3_step(S)] but has neither run to completion (returned
4374 ** [SQLITE_DONE] from [sqlite3_step(S)]) nor
4375 ** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
4376 ** interface returns false if S is a NULL pointer.  If S is not a
4377 ** NULL pointer and is not a pointer to a valid [prepared statement]
4378 ** object, then the behavior is undefined and probably undesirable.
4379 **
4380 ** This interface can be used in combination [sqlite3_next_stmt()]
4381 ** to locate all prepared statements associated with a database
4382 ** connection that are in need of being reset.  This can be used,
4383 ** for example, in diagnostic routines to search for prepared
4384 ** statements that are holding a transaction open.
4385 */
4386 SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
4387 
4388 /*
4389 ** CAPI3REF: Dynamically Typed Value Object
4390 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
4391 **
4392 ** SQLite uses the sqlite3_value object to represent all values
4393 ** that can be stored in a database table. SQLite uses dynamic typing
4394 ** for the values it stores.  ^Values stored in sqlite3_value objects
4395 ** can be integers, floating point values, strings, BLOBs, or NULL.
4396 **
4397 ** An sqlite3_value object may be either "protected" or "unprotected".
4398 ** Some interfaces require a protected sqlite3_value.  Other interfaces
4399 ** will accept either a protected or an unprotected sqlite3_value.
4400 ** Every interface that accepts sqlite3_value arguments specifies
4401 ** whether or not it requires a protected sqlite3_value.  The
4402 ** [sqlite3_value_dup()] interface can be used to construct a new
4403 ** protected sqlite3_value from an unprotected sqlite3_value.
4404 **
4405 ** The terms "protected" and "unprotected" refer to whether or not
4406 ** a mutex is held.  An internal mutex is held for a protected
4407 ** sqlite3_value object but no mutex is held for an unprotected
4408 ** sqlite3_value object.  If SQLite is compiled to be single-threaded
4409 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
4410 ** or if SQLite is run in one of reduced mutex modes
4411 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
4412 ** then there is no distinction between protected and unprotected
4413 ** sqlite3_value objects and they can be used interchangeably.  However,
4414 ** for maximum code portability it is recommended that applications
4415 ** still make the distinction between protected and unprotected
4416 ** sqlite3_value objects even when not strictly required.
4417 **
4418 ** ^The sqlite3_value objects that are passed as parameters into the
4419 ** implementation of [application-defined SQL functions] are protected.
4420 ** ^The sqlite3_value objects returned by [sqlite3_vtab_rhs_value()]
4421 ** are protected.
4422 ** ^The sqlite3_value object returned by
4423 ** [sqlite3_column_value()] is unprotected.
4424 ** Unprotected sqlite3_value objects may only be used as arguments
4425 ** to [sqlite3_result_value()], [sqlite3_bind_value()], and
4426 ** [sqlite3_value_dup()].
4427 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
4428 ** interfaces require protected sqlite3_value objects.
4429 */
4430 typedef struct sqlite3_value sqlite3_value;
4431 
4432 /*
4433 ** CAPI3REF: SQL Function Context Object
4434 **
4435 ** The context in which an SQL function executes is stored in an
4436 ** sqlite3_context object.  ^A pointer to an sqlite3_context object
4437 ** is always first parameter to [application-defined SQL functions].
4438 ** The application-defined SQL function implementation will pass this
4439 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
4440 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
4441 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
4442 ** and/or [sqlite3_set_auxdata()].
4443 */
4444 typedef struct sqlite3_context sqlite3_context;
4445 
4446 /*
4447 ** CAPI3REF: Binding Values To Prepared Statements
4448 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
4449 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
4450 ** METHOD: sqlite3_stmt
4451 **
4452 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
4453 ** literals may be replaced by a [parameter] that matches one of following
4454 ** templates:
4455 **
4456 ** <ul>
4457 ** <li>  ?
4458 ** <li>  ?NNN
4459 ** <li>  :VVV
4460 ** <li>  @VVV
4461 ** <li>  $VVV
4462 ** </ul>
4463 **
4464 ** In the templates above, NNN represents an integer literal,
4465 ** and VVV represents an alphanumeric identifier.)^  ^The values of these
4466 ** parameters (also called "host parameter names" or "SQL parameters")
4467 ** can be set using the sqlite3_bind_*() routines defined here.
4468 **
4469 ** ^The first argument to the sqlite3_bind_*() routines is always
4470 ** a pointer to the [sqlite3_stmt] object returned from
4471 ** [sqlite3_prepare_v2()] or its variants.
4472 **
4473 ** ^The second argument is the index of the SQL parameter to be set.
4474 ** ^The leftmost SQL parameter has an index of 1.  ^When the same named
4475 ** SQL parameter is used more than once, second and subsequent
4476 ** occurrences have the same index as the first occurrence.
4477 ** ^The index for named parameters can be looked up using the
4478 ** [sqlite3_bind_parameter_index()] API if desired.  ^The index
4479 ** for "?NNN" parameters is the value of NNN.
4480 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
4481 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766).
4482 **
4483 ** ^The third argument is the value to bind to the parameter.
4484 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4485 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
4486 ** is ignored and the end result is the same as sqlite3_bind_null().
4487 ** ^If the third parameter to sqlite3_bind_text() is not NULL, then
4488 ** it should be a pointer to well-formed UTF8 text.
4489 ** ^If the third parameter to sqlite3_bind_text16() is not NULL, then
4490 ** it should be a pointer to well-formed UTF16 text.
4491 ** ^If the third parameter to sqlite3_bind_text64() is not NULL, then
4492 ** it should be a pointer to a well-formed unicode string that is
4493 ** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16
4494 ** otherwise.
4495 **
4496 ** [[byte-order determination rules]] ^The byte-order of
4497 ** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF)
4498 ** found in first character, which is removed, or in the absence of a BOM
4499 ** the byte order is the native byte order of the host
4500 ** machine for sqlite3_bind_text16() or the byte order specified in
4501 ** the 6th parameter for sqlite3_bind_text64().)^
4502 ** ^If UTF16 input text contains invalid unicode
4503 ** characters, then SQLite might change those invalid characters
4504 ** into the unicode replacement character: U+FFFD.
4505 **
4506 ** ^(In those routines that have a fourth argument, its value is the
4507 ** number of bytes in the parameter.  To be clear: the value is the
4508 ** number of <u>bytes</u> in the value, not the number of characters.)^
4509 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4510 ** is negative, then the length of the string is
4511 ** the number of bytes up to the first zero terminator.
4512 ** If the fourth parameter to sqlite3_bind_blob() is negative, then
4513 ** the behavior is undefined.
4514 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
4515 ** or sqlite3_bind_text16() or sqlite3_bind_text64() then
4516 ** that parameter must be the byte offset
4517 ** where the NUL terminator would occur assuming the string were NUL
4518 ** terminated.  If any NUL characters occurs at byte offsets less than
4519 ** the value of the fourth parameter then the resulting string value will
4520 ** contain embedded NULs.  The result of expressions involving strings
4521 ** with embedded NULs is undefined.
4522 **
4523 ** ^The fifth argument to the BLOB and string binding interfaces controls
4524 ** or indicates the lifetime of the object referenced by the third parameter.
4525 ** These three options exist:
4526 ** ^ (1) A destructor to dispose of the BLOB or string after SQLite has finished
4527 ** with it may be passed. ^It is called to dispose of the BLOB or string even
4528 ** if the call to the bind API fails, except the destructor is not called if
4529 ** the third parameter is a NULL pointer or the fourth parameter is negative.
4530 ** ^ (2) The special constant, [SQLITE_STATIC], may be passsed to indicate that
4531 ** the application remains responsible for disposing of the object. ^In this
4532 ** case, the object and the provided pointer to it must remain valid until
4533 ** either the prepared statement is finalized or the same SQL parameter is
4534 ** bound to something else, whichever occurs sooner.
4535 ** ^ (3) The constant, [SQLITE_TRANSIENT], may be passed to indicate that the
4536 ** object is to be copied prior to the return from sqlite3_bind_*(). ^The
4537 ** object and pointer to it must remain valid until then. ^SQLite will then
4538 ** manage the lifetime of its private copy.
4539 **
4540 ** ^The sixth argument to sqlite3_bind_text64() must be one of
4541 ** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
4542 ** to specify the encoding of the text in the third parameter.  If
4543 ** the sixth argument to sqlite3_bind_text64() is not one of the
4544 ** allowed values shown above, or if the text encoding is different
4545 ** from the encoding specified by the sixth parameter, then the behavior
4546 ** is undefined.
4547 **
4548 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
4549 ** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
4550 ** (just an integer to hold its size) while it is being processed.
4551 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
4552 ** content is later written using
4553 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
4554 ** ^A negative value for the zeroblob results in a zero-length BLOB.
4555 **
4556 ** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
4557 ** [prepared statement] S to have an SQL value of NULL, but to also be
4558 ** associated with the pointer P of type T.  ^D is either a NULL pointer or
4559 ** a pointer to a destructor function for P. ^SQLite will invoke the
4560 ** destructor D with a single argument of P when it is finished using
4561 ** P.  The T parameter should be a static string, preferably a string
4562 ** literal. The sqlite3_bind_pointer() routine is part of the
4563 ** [pointer passing interface] added for SQLite 3.20.0.
4564 **
4565 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
4566 ** for the [prepared statement] or with a prepared statement for which
4567 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
4568 ** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
4569 ** routine is passed a [prepared statement] that has been finalized, the
4570 ** result is undefined and probably harmful.
4571 **
4572 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
4573 ** ^Unbound parameters are interpreted as NULL.
4574 **
4575 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
4576 ** [error code] if anything goes wrong.
4577 ** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
4578 ** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
4579 ** [SQLITE_MAX_LENGTH].
4580 ** ^[SQLITE_RANGE] is returned if the parameter
4581 ** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
4582 **
4583 ** See also: [sqlite3_bind_parameter_count()],
4584 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
4585 */
4586 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
4587 SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
4588                         void(*)(void*));
4589 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
4590 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
4591 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
4592 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
4593 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
4594 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
4595 SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
4596                          void(*)(void*), unsigned char encoding);
4597 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
4598 SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
4599 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
4600 SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
4601 
4602 /*
4603 ** CAPI3REF: Number Of SQL Parameters
4604 ** METHOD: sqlite3_stmt
4605 **
4606 ** ^This routine can be used to find the number of [SQL parameters]
4607 ** in a [prepared statement].  SQL parameters are tokens of the
4608 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
4609 ** placeholders for values that are [sqlite3_bind_blob | bound]
4610 ** to the parameters at a later time.
4611 **
4612 ** ^(This routine actually returns the index of the largest (rightmost)
4613 ** parameter. For all forms except ?NNN, this will correspond to the
4614 ** number of unique parameters.  If parameters of the ?NNN form are used,
4615 ** there may be gaps in the list.)^
4616 **
4617 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4618 ** [sqlite3_bind_parameter_name()], and
4619 ** [sqlite3_bind_parameter_index()].
4620 */
4621 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
4622 
4623 /*
4624 ** CAPI3REF: Name Of A Host Parameter
4625 ** METHOD: sqlite3_stmt
4626 **
4627 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
4628 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
4629 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
4630 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
4631 ** respectively.
4632 ** In other words, the initial ":" or "$" or "@" or "?"
4633 ** is included as part of the name.)^
4634 ** ^Parameters of the form "?" without a following integer have no name
4635 ** and are referred to as "nameless" or "anonymous parameters".
4636 **
4637 ** ^The first host parameter has an index of 1, not 0.
4638 **
4639 ** ^If the value N is out of range or if the N-th parameter is
4640 ** nameless, then NULL is returned.  ^The returned string is
4641 ** always in UTF-8 encoding even if the named parameter was
4642 ** originally specified as UTF-16 in [sqlite3_prepare16()],
4643 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4644 **
4645 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4646 ** [sqlite3_bind_parameter_count()], and
4647 ** [sqlite3_bind_parameter_index()].
4648 */
4649 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
4650 
4651 /*
4652 ** CAPI3REF: Index Of A Parameter With A Given Name
4653 ** METHOD: sqlite3_stmt
4654 **
4655 ** ^Return the index of an SQL parameter given its name.  ^The
4656 ** index value returned is suitable for use as the second
4657 ** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
4658 ** is returned if no matching parameter is found.  ^The parameter
4659 ** name must be given in UTF-8 even if the original statement
4660 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
4661 ** [sqlite3_prepare16_v3()].
4662 **
4663 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4664 ** [sqlite3_bind_parameter_count()], and
4665 ** [sqlite3_bind_parameter_name()].
4666 */
4667 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
4668 
4669 /*
4670 ** CAPI3REF: Reset All Bindings On A Prepared Statement
4671 ** METHOD: sqlite3_stmt
4672 **
4673 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
4674 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
4675 ** ^Use this routine to reset all host parameters to NULL.
4676 */
4677 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
4678 
4679 /*
4680 ** CAPI3REF: Number Of Columns In A Result Set
4681 ** METHOD: sqlite3_stmt
4682 **
4683 ** ^Return the number of columns in the result set returned by the
4684 ** [prepared statement]. ^If this routine returns 0, that means the
4685 ** [prepared statement] returns no data (for example an [UPDATE]).
4686 ** ^However, just because this routine returns a positive number does not
4687 ** mean that one or more rows of data will be returned.  ^A SELECT statement
4688 ** will always have a positive sqlite3_column_count() but depending on the
4689 ** WHERE clause constraints and the table content, it might return no rows.
4690 **
4691 ** See also: [sqlite3_data_count()]
4692 */
4693 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
4694 
4695 /*
4696 ** CAPI3REF: Column Names In A Result Set
4697 ** METHOD: sqlite3_stmt
4698 **
4699 ** ^These routines return the name assigned to a particular column
4700 ** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
4701 ** interface returns a pointer to a zero-terminated UTF-8 string
4702 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
4703 ** UTF-16 string.  ^The first parameter is the [prepared statement]
4704 ** that implements the [SELECT] statement. ^The second parameter is the
4705 ** column number.  ^The leftmost column is number 0.
4706 **
4707 ** ^The returned string pointer is valid until either the [prepared statement]
4708 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
4709 ** reprepared by the first call to [sqlite3_step()] for a particular run
4710 ** or until the next call to
4711 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
4712 **
4713 ** ^If sqlite3_malloc() fails during the processing of either routine
4714 ** (for example during a conversion from UTF-8 to UTF-16) then a
4715 ** NULL pointer is returned.
4716 **
4717 ** ^The name of a result column is the value of the "AS" clause for
4718 ** that column, if there is an AS clause.  If there is no AS clause
4719 ** then the name of the column is unspecified and may change from
4720 ** one release of SQLite to the next.
4721 */
4722 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
4723 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
4724 
4725 /*
4726 ** CAPI3REF: Source Of Data In A Query Result
4727 ** METHOD: sqlite3_stmt
4728 **
4729 ** ^These routines provide a means to determine the database, table, and
4730 ** table column that is the origin of a particular result column in
4731 ** [SELECT] statement.
4732 ** ^The name of the database or table or column can be returned as
4733 ** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
4734 ** the database name, the _table_ routines return the table name, and
4735 ** the origin_ routines return the column name.
4736 ** ^The returned string is valid until the [prepared statement] is destroyed
4737 ** using [sqlite3_finalize()] or until the statement is automatically
4738 ** reprepared by the first call to [sqlite3_step()] for a particular run
4739 ** or until the same information is requested
4740 ** again in a different encoding.
4741 **
4742 ** ^The names returned are the original un-aliased names of the
4743 ** database, table, and column.
4744 **
4745 ** ^The first argument to these interfaces is a [prepared statement].
4746 ** ^These functions return information about the Nth result column returned by
4747 ** the statement, where N is the second function argument.
4748 ** ^The left-most column is column 0 for these routines.
4749 **
4750 ** ^If the Nth column returned by the statement is an expression or
4751 ** subquery and is not a column value, then all of these functions return
4752 ** NULL.  ^These routines might also return NULL if a memory allocation error
4753 ** occurs.  ^Otherwise, they return the name of the attached database, table,
4754 ** or column that query result column was extracted from.
4755 **
4756 ** ^As with all other SQLite APIs, those whose names end with "16" return
4757 ** UTF-16 encoded strings and the other functions return UTF-8.
4758 **
4759 ** ^These APIs are only available if the library was compiled with the
4760 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
4761 **
4762 ** If two or more threads call one or more
4763 ** [sqlite3_column_database_name | column metadata interfaces]
4764 ** for the same [prepared statement] and result column
4765 ** at the same time then the results are undefined.
4766 */
4767 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
4768 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
4769 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
4770 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
4771 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
4772 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
4773 
4774 /*
4775 ** CAPI3REF: Declared Datatype Of A Query Result
4776 ** METHOD: sqlite3_stmt
4777 **
4778 ** ^(The first parameter is a [prepared statement].
4779 ** If this statement is a [SELECT] statement and the Nth column of the
4780 ** returned result set of that [SELECT] is a table column (not an
4781 ** expression or subquery) then the declared type of the table
4782 ** column is returned.)^  ^If the Nth column of the result set is an
4783 ** expression or subquery, then a NULL pointer is returned.
4784 ** ^The returned string is always UTF-8 encoded.
4785 **
4786 ** ^(For example, given the database schema:
4787 **
4788 ** CREATE TABLE t1(c1 VARIANT);
4789 **
4790 ** and the following statement to be compiled:
4791 **
4792 ** SELECT c1 + 1, c1 FROM t1;
4793 **
4794 ** this routine would return the string "VARIANT" for the second result
4795 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
4796 **
4797 ** ^SQLite uses dynamic run-time typing.  ^So just because a column
4798 ** is declared to contain a particular type does not mean that the
4799 ** data stored in that column is of the declared type.  SQLite is
4800 ** strongly typed, but the typing is dynamic not static.  ^Type
4801 ** is associated with individual values, not with the containers
4802 ** used to hold those values.
4803 */
4804 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
4805 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
4806 
4807 /*
4808 ** CAPI3REF: Evaluate An SQL Statement
4809 ** METHOD: sqlite3_stmt
4810 **
4811 ** After a [prepared statement] has been prepared using any of
4812 ** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
4813 ** or [sqlite3_prepare16_v3()] or one of the legacy
4814 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
4815 ** must be called one or more times to evaluate the statement.
4816 **
4817 ** The details of the behavior of the sqlite3_step() interface depend
4818 ** on whether the statement was prepared using the newer "vX" interfaces
4819 ** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
4820 ** [sqlite3_prepare16_v2()] or the older legacy
4821 ** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
4822 ** new "vX" interface is recommended for new applications but the legacy
4823 ** interface will continue to be supported.
4824 **
4825 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
4826 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
4827 ** ^With the "v2" interface, any of the other [result codes] or
4828 ** [extended result codes] might be returned as well.
4829 **
4830 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
4831 ** database locks it needs to do its job.  ^If the statement is a [COMMIT]
4832 ** or occurs outside of an explicit transaction, then you can retry the
4833 ** statement.  If the statement is not a [COMMIT] and occurs within an
4834 ** explicit transaction then you should rollback the transaction before
4835 ** continuing.
4836 **
4837 ** ^[SQLITE_DONE] means that the statement has finished executing
4838 ** successfully.  sqlite3_step() should not be called again on this virtual
4839 ** machine without first calling [sqlite3_reset()] to reset the virtual
4840 ** machine back to its initial state.
4841 **
4842 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
4843 ** is returned each time a new row of data is ready for processing by the
4844 ** caller. The values may be accessed using the [column access functions].
4845 ** sqlite3_step() is called again to retrieve the next row of data.
4846 **
4847 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
4848 ** violation) has occurred.  sqlite3_step() should not be called again on
4849 ** the VM. More information may be found by calling [sqlite3_errmsg()].
4850 ** ^With the legacy interface, a more specific error code (for example,
4851 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
4852 ** can be obtained by calling [sqlite3_reset()] on the
4853 ** [prepared statement].  ^In the "v2" interface,
4854 ** the more specific error code is returned directly by sqlite3_step().
4855 **
4856 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
4857 ** Perhaps it was called on a [prepared statement] that has
4858 ** already been [sqlite3_finalize | finalized] or on one that had
4859 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
4860 ** be the case that the same database connection is being used by two or
4861 ** more threads at the same moment in time.
4862 **
4863 ** For all versions of SQLite up to and including 3.6.23.1, a call to
4864 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
4865 ** other than [SQLITE_ROW] before any subsequent invocation of
4866 ** sqlite3_step().  Failure to reset the prepared statement using
4867 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
4868 ** sqlite3_step().  But after [version 3.6.23.1] ([dateof:3.6.23.1],
4869 ** sqlite3_step() began
4870 ** calling [sqlite3_reset()] automatically in this circumstance rather
4871 ** than returning [SQLITE_MISUSE].  This is not considered a compatibility
4872 ** break because any application that ever receives an SQLITE_MISUSE error
4873 ** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
4874 ** can be used to restore the legacy behavior.
4875 **
4876 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
4877 ** API always returns a generic error code, [SQLITE_ERROR], following any
4878 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
4879 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
4880 ** specific [error codes] that better describes the error.
4881 ** We admit that this is a goofy design.  The problem has been fixed
4882 ** with the "v2" interface.  If you prepare all of your SQL statements
4883 ** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
4884 ** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
4885 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
4886 ** then the more specific [error codes] are returned directly
4887 ** by sqlite3_step().  The use of the "vX" interfaces is recommended.
4888 */
4889 SQLITE_API int sqlite3_step(sqlite3_stmt*);
4890 
4891 /*
4892 ** CAPI3REF: Number of columns in a result set
4893 ** METHOD: sqlite3_stmt
4894 **
4895 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
4896 ** current row of the result set of [prepared statement] P.
4897 ** ^If prepared statement P does not have results ready to return
4898 ** (via calls to the [sqlite3_column_int | sqlite3_column()] family of
4899 ** interfaces) then sqlite3_data_count(P) returns 0.
4900 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
4901 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
4902 ** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
4903 ** will return non-zero if previous call to [sqlite3_step](P) returned
4904 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
4905 ** where it always returns zero since each step of that multi-step
4906 ** pragma returns 0 columns of data.
4907 **
4908 ** See also: [sqlite3_column_count()]
4909 */
4910 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
4911 
4912 /*
4913 ** CAPI3REF: Fundamental Datatypes
4914 ** KEYWORDS: SQLITE_TEXT
4915 **
4916 ** ^(Every value in SQLite has one of five fundamental datatypes:
4917 **
4918 ** <ul>
4919 ** <li> 64-bit signed integer
4920 ** <li> 64-bit IEEE floating point number
4921 ** <li> string
4922 ** <li> BLOB
4923 ** <li> NULL
4924 ** </ul>)^
4925 **
4926 ** These constants are codes for each of those types.
4927 **
4928 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
4929 ** for a completely different meaning.  Software that links against both
4930 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
4931 ** SQLITE_TEXT.
4932 */
4933 #define SQLITE_INTEGER  1
4934 #define SQLITE_FLOAT    2
4935 #define SQLITE_BLOB     4
4936 #define SQLITE_NULL     5
4937 #ifdef SQLITE_TEXT
4938 # undef SQLITE_TEXT
4939 #else
4940 # define SQLITE_TEXT     3
4941 #endif
4942 #define SQLITE3_TEXT     3
4943 
4944 /*
4945 ** CAPI3REF: Result Values From A Query
4946 ** KEYWORDS: {column access functions}
4947 ** METHOD: sqlite3_stmt
4948 **
4949 ** <b>Summary:</b>
4950 ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
4951 ** <tr><td><b>sqlite3_column_blob</b><td>&rarr;<td>BLOB result
4952 ** <tr><td><b>sqlite3_column_double</b><td>&rarr;<td>REAL result
4953 ** <tr><td><b>sqlite3_column_int</b><td>&rarr;<td>32-bit INTEGER result
4954 ** <tr><td><b>sqlite3_column_int64</b><td>&rarr;<td>64-bit INTEGER result
4955 ** <tr><td><b>sqlite3_column_text</b><td>&rarr;<td>UTF-8 TEXT result
4956 ** <tr><td><b>sqlite3_column_text16</b><td>&rarr;<td>UTF-16 TEXT result
4957 ** <tr><td><b>sqlite3_column_value</b><td>&rarr;<td>The result as an
4958 ** [sqlite3_value|unprotected sqlite3_value] object.
4959 ** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
4960 ** <tr><td><b>sqlite3_column_bytes</b><td>&rarr;<td>Size of a BLOB
4961 ** or a UTF-8 TEXT result in bytes
4962 ** <tr><td><b>sqlite3_column_bytes16&nbsp;&nbsp;</b>
4963 ** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
4964 ** TEXT in bytes
4965 ** <tr><td><b>sqlite3_column_type</b><td>&rarr;<td>Default
4966 ** datatype of the result
4967 ** </table></blockquote>
4968 **
4969 ** <b>Details:</b>
4970 **
4971 ** ^These routines return information about a single column of the current
4972 ** result row of a query.  ^In every case the first argument is a pointer
4973 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
4974 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
4975 ** and the second argument is the index of the column for which information
4976 ** should be returned. ^The leftmost column of the result set has the index 0.
4977 ** ^The number of columns in the result can be determined using
4978 ** [sqlite3_column_count()].
4979 **
4980 ** If the SQL statement does not currently point to a valid row, or if the
4981 ** column index is out of range, the result is undefined.
4982 ** These routines may only be called when the most recent call to
4983 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
4984 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
4985 ** If any of these routines are called after [sqlite3_reset()] or
4986 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
4987 ** something other than [SQLITE_ROW], the results are undefined.
4988 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
4989 ** are called from a different thread while any of these routines
4990 ** are pending, then the results are undefined.
4991 **
4992 ** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
4993 ** each return the value of a result column in a specific data format.  If
4994 ** the result column is not initially in the requested format (for example,
4995 ** if the query returns an integer but the sqlite3_column_text() interface
4996 ** is used to extract the value) then an automatic type conversion is performed.
4997 **
4998 ** ^The sqlite3_column_type() routine returns the
4999 ** [SQLITE_INTEGER | datatype code] for the initial data type
5000 ** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
5001 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
5002 ** The return value of sqlite3_column_type() can be used to decide which
5003 ** of the first six interface should be used to extract the column value.
5004 ** The value returned by sqlite3_column_type() is only meaningful if no
5005 ** automatic type conversions have occurred for the value in question.
5006 ** After a type conversion, the result of calling sqlite3_column_type()
5007 ** is undefined, though harmless.  Future
5008 ** versions of SQLite may change the behavior of sqlite3_column_type()
5009 ** following a type conversion.
5010 **
5011 ** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
5012 ** or sqlite3_column_bytes16() interfaces can be used to determine the size
5013 ** of that BLOB or string.
5014 **
5015 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
5016 ** routine returns the number of bytes in that BLOB or string.
5017 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
5018 ** the string to UTF-8 and then returns the number of bytes.
5019 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
5020 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
5021 ** the number of bytes in that string.
5022 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
5023 **
5024 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
5025 ** routine returns the number of bytes in that BLOB or string.
5026 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
5027 ** the string to UTF-16 and then returns the number of bytes.
5028 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
5029 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
5030 ** the number of bytes in that string.
5031 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
5032 **
5033 ** ^The values returned by [sqlite3_column_bytes()] and
5034 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
5035 ** of the string.  ^For clarity: the values returned by
5036 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
5037 ** bytes in the string, not the number of characters.
5038 **
5039 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
5040 ** even empty strings, are always zero-terminated.  ^The return
5041 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
5042 **
5043 ** ^Strings returned by sqlite3_column_text16() always have the endianness
5044 ** which is native to the platform, regardless of the text encoding set
5045 ** for the database.
5046 **
5047 ** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
5048 ** [unprotected sqlite3_value] object.  In a multithreaded environment,
5049 ** an unprotected sqlite3_value object may only be used safely with
5050 ** [sqlite3_bind_value()] and [sqlite3_result_value()].
5051 ** If the [unprotected sqlite3_value] object returned by
5052 ** [sqlite3_column_value()] is used in any other way, including calls
5053 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
5054 ** or [sqlite3_value_bytes()], the behavior is not threadsafe.
5055 ** Hence, the sqlite3_column_value() interface
5056 ** is normally only useful within the implementation of
5057 ** [application-defined SQL functions] or [virtual tables], not within
5058 ** top-level application code.
5059 **
5060 ** These routines may attempt to convert the datatype of the result.
5061 ** ^For example, if the internal representation is FLOAT and a text result
5062 ** is requested, [sqlite3_snprintf()] is used internally to perform the
5063 ** conversion automatically.  ^(The following table details the conversions
5064 ** that are applied:
5065 **
5066 ** <blockquote>
5067 ** <table border="1">
5068 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
5069 **
5070 ** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
5071 ** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
5072 ** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
5073 ** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
5074 ** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
5075 ** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
5076 ** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
5077 ** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
5078 ** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
5079 ** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
5080 ** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
5081 ** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
5082 ** <tr><td>  TEXT    <td>   BLOB    <td> No change
5083 ** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
5084 ** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
5085 ** <tr><td>  BLOB    <td>   TEXT    <td> [CAST] to TEXT, ensure zero terminator
5086 ** </table>
5087 ** </blockquote>)^
5088 **
5089 ** Note that when type conversions occur, pointers returned by prior
5090 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
5091 ** sqlite3_column_text16() may be invalidated.
5092 ** Type conversions and pointer invalidations might occur
5093 ** in the following cases:
5094 **
5095 ** <ul>
5096 ** <li> The initial content is a BLOB and sqlite3_column_text() or
5097 **      sqlite3_column_text16() is called.  A zero-terminator might
5098 **      need to be added to the string.</li>
5099 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
5100 **      sqlite3_column_text16() is called.  The content must be converted
5101 **      to UTF-16.</li>
5102 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
5103 **      sqlite3_column_text() is called.  The content must be converted
5104 **      to UTF-8.</li>
5105 ** </ul>
5106 **
5107 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
5108 ** not invalidate a prior pointer, though of course the content of the buffer
5109 ** that the prior pointer references will have been modified.  Other kinds
5110 ** of conversion are done in place when it is possible, but sometimes they
5111 ** are not possible and in those cases prior pointers are invalidated.
5112 **
5113 ** The safest policy is to invoke these routines
5114 ** in one of the following ways:
5115 **
5116 ** <ul>
5117 **  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
5118 **  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
5119 **  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
5120 ** </ul>
5121 **
5122 ** In other words, you should call sqlite3_column_text(),
5123 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
5124 ** into the desired format, then invoke sqlite3_column_bytes() or
5125 ** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
5126 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
5127 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
5128 ** with calls to sqlite3_column_bytes().
5129 **
5130 ** ^The pointers returned are valid until a type conversion occurs as
5131 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
5132 ** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
5133 ** and BLOBs is freed automatically.  Do not pass the pointers returned
5134 ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
5135 ** [sqlite3_free()].
5136 **
5137 ** As long as the input parameters are correct, these routines will only
5138 ** fail if an out-of-memory error occurs during a format conversion.
5139 ** Only the following subset of interfaces are subject to out-of-memory
5140 ** errors:
5141 **
5142 ** <ul>
5143 ** <li> sqlite3_column_blob()
5144 ** <li> sqlite3_column_text()
5145 ** <li> sqlite3_column_text16()
5146 ** <li> sqlite3_column_bytes()
5147 ** <li> sqlite3_column_bytes16()
5148 ** </ul>
5149 **
5150 ** If an out-of-memory error occurs, then the return value from these
5151 ** routines is the same as if the column had contained an SQL NULL value.
5152 ** Valid SQL NULL returns can be distinguished from out-of-memory errors
5153 ** by invoking the [sqlite3_errcode()] immediately after the suspect
5154 ** return value is obtained and before any
5155 ** other SQLite interface is called on the same [database connection].
5156 */
5157 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
5158 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
5159 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
5160 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
5161 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
5162 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
5163 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
5164 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
5165 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
5166 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
5167 
5168 /*
5169 ** CAPI3REF: Destroy A Prepared Statement Object
5170 ** DESTRUCTOR: sqlite3_stmt
5171 **
5172 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
5173 ** ^If the most recent evaluation of the statement encountered no errors
5174 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
5175 ** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
5176 ** sqlite3_finalize(S) returns the appropriate [error code] or
5177 ** [extended error code].
5178 **
5179 ** ^The sqlite3_finalize(S) routine can be called at any point during
5180 ** the life cycle of [prepared statement] S:
5181 ** before statement S is ever evaluated, after
5182 ** one or more calls to [sqlite3_reset()], or after any call
5183 ** to [sqlite3_step()] regardless of whether or not the statement has
5184 ** completed execution.
5185 **
5186 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
5187 **
5188 ** The application must finalize every [prepared statement] in order to avoid
5189 ** resource leaks.  It is a grievous error for the application to try to use
5190 ** a prepared statement after it has been finalized.  Any use of a prepared
5191 ** statement after it has been finalized can result in undefined and
5192 ** undesirable behavior such as segfaults and heap corruption.
5193 */
5194 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
5195 
5196 /*
5197 ** CAPI3REF: Reset A Prepared Statement Object
5198 ** METHOD: sqlite3_stmt
5199 **
5200 ** The sqlite3_reset() function is called to reset a [prepared statement]
5201 ** object back to its initial state, ready to be re-executed.
5202 ** ^Any SQL statement variables that had values bound to them using
5203 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
5204 ** Use [sqlite3_clear_bindings()] to reset the bindings.
5205 **
5206 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
5207 ** back to the beginning of its program.
5208 **
5209 ** ^If the most recent call to [sqlite3_step(S)] for the
5210 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
5211 ** or if [sqlite3_step(S)] has never before been called on S,
5212 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
5213 **
5214 ** ^If the most recent call to [sqlite3_step(S)] for the
5215 ** [prepared statement] S indicated an error, then
5216 ** [sqlite3_reset(S)] returns an appropriate [error code].
5217 **
5218 ** ^The [sqlite3_reset(S)] interface does not change the values
5219 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
5220 */
5221 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
5222 
5223 /*
5224 ** CAPI3REF: Create Or Redefine SQL Functions
5225 ** KEYWORDS: {function creation routines}
5226 ** METHOD: sqlite3
5227 **
5228 ** ^These functions (collectively known as "function creation routines")
5229 ** are used to add SQL functions or aggregates or to redefine the behavior
5230 ** of existing SQL functions or aggregates. The only differences between
5231 ** the three "sqlite3_create_function*" routines are the text encoding
5232 ** expected for the second parameter (the name of the function being
5233 ** created) and the presence or absence of a destructor callback for
5234 ** the application data pointer. Function sqlite3_create_window_function()
5235 ** is similar, but allows the user to supply the extra callback functions
5236 ** needed by [aggregate window functions].
5237 **
5238 ** ^The first parameter is the [database connection] to which the SQL
5239 ** function is to be added.  ^If an application uses more than one database
5240 ** connection then application-defined SQL functions must be added
5241 ** to each database connection separately.
5242 **
5243 ** ^The second parameter is the name of the SQL function to be created or
5244 ** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
5245 ** representation, exclusive of the zero-terminator.  ^Note that the name
5246 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
5247 ** ^Any attempt to create a function with a longer name
5248 ** will result in [SQLITE_MISUSE] being returned.
5249 **
5250 ** ^The third parameter (nArg)
5251 ** is the number of arguments that the SQL function or
5252 ** aggregate takes. ^If this parameter is -1, then the SQL function or
5253 ** aggregate may take any number of arguments between 0 and the limit
5254 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
5255 ** parameter is less than -1 or greater than 127 then the behavior is
5256 ** undefined.
5257 **
5258 ** ^The fourth parameter, eTextRep, specifies what
5259 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
5260 ** its parameters.  The application should set this parameter to
5261 ** [SQLITE_UTF16LE] if the function implementation invokes
5262 ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
5263 ** implementation invokes [sqlite3_value_text16be()] on an input, or
5264 ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
5265 ** otherwise.  ^The same SQL function may be registered multiple times using
5266 ** different preferred text encodings, with different implementations for
5267 ** each encoding.
5268 ** ^When multiple implementations of the same function are available, SQLite
5269 ** will pick the one that involves the least amount of data conversion.
5270 **
5271 ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
5272 ** to signal that the function will always return the same result given
5273 ** the same inputs within a single SQL statement.  Most SQL functions are
5274 ** deterministic.  The built-in [random()] SQL function is an example of a
5275 ** function that is not deterministic.  The SQLite query planner is able to
5276 ** perform additional optimizations on deterministic functions, so use
5277 ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
5278 **
5279 ** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY]
5280 ** flag, which if present prevents the function from being invoked from
5281 ** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions,
5282 ** index expressions, or the WHERE clause of partial indexes.
5283 **
5284 ** For best security, the [SQLITE_DIRECTONLY] flag is recommended for
5285 ** all application-defined SQL functions that do not need to be
5286 ** used inside of triggers, view, CHECK constraints, or other elements of
5287 ** the database schema.  This flags is especially recommended for SQL
5288 ** functions that have side effects or reveal internal application state.
5289 ** Without this flag, an attacker might be able to modify the schema of
5290 ** a database file to include invocations of the function with parameters
5291 ** chosen by the attacker, which the application will then execute when
5292 ** the database file is opened and read.
5293 **
5294 ** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
5295 ** function can gain access to this pointer using [sqlite3_user_data()].)^
5296 **
5297 ** ^The sixth, seventh and eighth parameters passed to the three
5298 ** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
5299 ** pointers to C-language functions that implement the SQL function or
5300 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
5301 ** callback only; NULL pointers must be passed as the xStep and xFinal
5302 ** parameters. ^An aggregate SQL function requires an implementation of xStep
5303 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
5304 ** SQL function or aggregate, pass NULL pointers for all three function
5305 ** callbacks.
5306 **
5307 ** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
5308 ** and xInverse) passed to sqlite3_create_window_function are pointers to
5309 ** C-language callbacks that implement the new function. xStep and xFinal
5310 ** must both be non-NULL. xValue and xInverse may either both be NULL, in
5311 ** which case a regular aggregate function is created, or must both be
5312 ** non-NULL, in which case the new function may be used as either an aggregate
5313 ** or aggregate window function. More details regarding the implementation
5314 ** of aggregate window functions are
5315 ** [user-defined window functions|available here].
5316 **
5317 ** ^(If the final parameter to sqlite3_create_function_v2() or
5318 ** sqlite3_create_window_function() is not NULL, then it is destructor for
5319 ** the application data pointer. The destructor is invoked when the function
5320 ** is deleted, either by being overloaded or when the database connection
5321 ** closes.)^ ^The destructor is also invoked if the call to
5322 ** sqlite3_create_function_v2() fails.  ^When the destructor callback is
5323 ** invoked, it is passed a single argument which is a copy of the application
5324 ** data pointer which was the fifth parameter to sqlite3_create_function_v2().
5325 **
5326 ** ^It is permitted to register multiple implementations of the same
5327 ** functions with the same name but with either differing numbers of
5328 ** arguments or differing preferred text encodings.  ^SQLite will use
5329 ** the implementation that most closely matches the way in which the
5330 ** SQL function is used.  ^A function implementation with a non-negative
5331 ** nArg parameter is a better match than a function implementation with
5332 ** a negative nArg.  ^A function where the preferred text encoding
5333 ** matches the database encoding is a better
5334 ** match than a function where the encoding is different.
5335 ** ^A function where the encoding difference is between UTF16le and UTF16be
5336 ** is a closer match than a function where the encoding difference is
5337 ** between UTF8 and UTF16.
5338 **
5339 ** ^Built-in functions may be overloaded by new application-defined functions.
5340 **
5341 ** ^An application-defined function is permitted to call other
5342 ** SQLite interfaces.  However, such calls must not
5343 ** close the database connection nor finalize or reset the prepared
5344 ** statement in which the function is running.
5345 */
5346 SQLITE_API int sqlite3_create_function(
5347   sqlite3 *db,
5348   const char *zFunctionName,
5349   int nArg,
5350   int eTextRep,
5351   void *pApp,
5352   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
5353   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5354   void (*xFinal)(sqlite3_context*)
5355 );
5356 SQLITE_API int sqlite3_create_function16(
5357   sqlite3 *db,
5358   const void *zFunctionName,
5359   int nArg,
5360   int eTextRep,
5361   void *pApp,
5362   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
5363   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5364   void (*xFinal)(sqlite3_context*)
5365 );
5366 SQLITE_API int sqlite3_create_function_v2(
5367   sqlite3 *db,
5368   const char *zFunctionName,
5369   int nArg,
5370   int eTextRep,
5371   void *pApp,
5372   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
5373   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5374   void (*xFinal)(sqlite3_context*),
5375   void(*xDestroy)(void*)
5376 );
5377 SQLITE_API int sqlite3_create_window_function(
5378   sqlite3 *db,
5379   const char *zFunctionName,
5380   int nArg,
5381   int eTextRep,
5382   void *pApp,
5383   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5384   void (*xFinal)(sqlite3_context*),
5385   void (*xValue)(sqlite3_context*),
5386   void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
5387   void(*xDestroy)(void*)
5388 );
5389 
5390 /*
5391 ** CAPI3REF: Text Encodings
5392 **
5393 ** These constant define integer codes that represent the various
5394 ** text encodings supported by SQLite.
5395 */
5396 #define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
5397 #define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
5398 #define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
5399 #define SQLITE_UTF16          4    /* Use native byte order */
5400 #define SQLITE_ANY            5    /* Deprecated */
5401 #define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
5402 
5403 /*
5404 ** CAPI3REF: Function Flags
5405 **
5406 ** These constants may be ORed together with the
5407 ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
5408 ** to [sqlite3_create_function()], [sqlite3_create_function16()], or
5409 ** [sqlite3_create_function_v2()].
5410 **
5411 ** <dl>
5412 ** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd>
5413 ** The SQLITE_DETERMINISTIC flag means that the new function always gives
5414 ** the same output when the input parameters are the same.
5415 ** The [abs|abs() function] is deterministic, for example, but
5416 ** [randomblob|randomblob()] is not.  Functions must
5417 ** be deterministic in order to be used in certain contexts such as
5418 ** with the WHERE clause of [partial indexes] or in [generated columns].
5419 ** SQLite might also optimize deterministic functions by factoring them
5420 ** out of inner loops.
5421 ** </dd>
5422 **
5423 ** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd>
5424 ** The SQLITE_DIRECTONLY flag means that the function may only be invoked
5425 ** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in
5426 ** schema structures such as [CHECK constraints], [DEFAULT clauses],
5427 ** [expression indexes], [partial indexes], or [generated columns].
5428 ** <p>
5429 ** The SQLITE_DIRECTONLY flag is recommended for any
5430 ** [application-defined SQL function]
5431 ** that has side-effects or that could potentially leak sensitive information.
5432 ** This will prevent attacks in which an application is tricked
5433 ** into using a database file that has had its schema surreptiously
5434 ** modified to invoke the application-defined function in ways that are
5435 ** harmful.
5436 ** <p>
5437 ** Some people say it is good practice to set SQLITE_DIRECTONLY on all
5438 ** [application-defined SQL functions], regardless of whether or not they
5439 ** are security sensitive, as doing so prevents those functions from being used
5440 ** inside of the database schema, and thus ensures that the database
5441 ** can be inspected and modified using generic tools (such as the [CLI])
5442 ** that do not have access to the application-defined functions.
5443 ** </dd>
5444 **
5445 ** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd>
5446 ** The SQLITE_INNOCUOUS flag means that the function is unlikely
5447 ** to cause problems even if misused.  An innocuous function should have
5448 ** no side effects and should not depend on any values other than its
5449 ** input parameters. The [abs|abs() function] is an example of an
5450 ** innocuous function.
5451 ** The [load_extension() SQL function] is not innocuous because of its
5452 ** side effects.
5453 ** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not
5454 ** exactly the same.  The [random|random() function] is an example of a
5455 ** function that is innocuous but not deterministic.
5456 ** <p>Some heightened security settings
5457 ** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF])
5458 ** disable the use of SQL functions inside views and triggers and in
5459 ** schema structures such as [CHECK constraints], [DEFAULT clauses],
5460 ** [expression indexes], [partial indexes], and [generated columns] unless
5461 ** the function is tagged with SQLITE_INNOCUOUS.  Most built-in functions
5462 ** are innocuous.  Developers are advised to avoid using the
5463 ** SQLITE_INNOCUOUS flag for application-defined functions unless the
5464 ** function has been carefully audited and found to be free of potentially
5465 ** security-adverse side-effects and information-leaks.
5466 ** </dd>
5467 **
5468 ** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd>
5469 ** The SQLITE_SUBTYPE flag indicates to SQLite that a function may call
5470 ** [sqlite3_value_subtype()] to inspect the sub-types of its arguments.
5471 ** Specifying this flag makes no difference for scalar or aggregate user
5472 ** functions. However, if it is not specified for a user-defined window
5473 ** function, then any sub-types belonging to arguments passed to the window
5474 ** function may be discarded before the window function is called (i.e.
5475 ** sqlite3_value_subtype() will always return 0).
5476 ** </dd>
5477 ** </dl>
5478 */
5479 #define SQLITE_DETERMINISTIC    0x000000800
5480 #define SQLITE_DIRECTONLY       0x000080000
5481 #define SQLITE_SUBTYPE          0x000100000
5482 #define SQLITE_INNOCUOUS        0x000200000
5483 
5484 /*
5485 ** CAPI3REF: Deprecated Functions
5486 ** DEPRECATED
5487 **
5488 ** These functions are [deprecated].  In order to maintain
5489 ** backwards compatibility with older code, these functions continue
5490 ** to be supported.  However, new applications should avoid
5491 ** the use of these functions.  To encourage programmers to avoid
5492 ** these functions, we will not explain what they do.
5493 */
5494 #ifndef SQLITE_OMIT_DEPRECATED
5495 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
5496 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
5497 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
5498 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
5499 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
5500 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
5501                       void*,sqlite3_int64);
5502 #endif
5503 
5504 /*
5505 ** CAPI3REF: Obtaining SQL Values
5506 ** METHOD: sqlite3_value
5507 **
5508 ** <b>Summary:</b>
5509 ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
5510 ** <tr><td><b>sqlite3_value_blob</b><td>&rarr;<td>BLOB value
5511 ** <tr><td><b>sqlite3_value_double</b><td>&rarr;<td>REAL value
5512 ** <tr><td><b>sqlite3_value_int</b><td>&rarr;<td>32-bit INTEGER value
5513 ** <tr><td><b>sqlite3_value_int64</b><td>&rarr;<td>64-bit INTEGER value
5514 ** <tr><td><b>sqlite3_value_pointer</b><td>&rarr;<td>Pointer value
5515 ** <tr><td><b>sqlite3_value_text</b><td>&rarr;<td>UTF-8 TEXT value
5516 ** <tr><td><b>sqlite3_value_text16</b><td>&rarr;<td>UTF-16 TEXT value in
5517 ** the native byteorder
5518 ** <tr><td><b>sqlite3_value_text16be</b><td>&rarr;<td>UTF-16be TEXT value
5519 ** <tr><td><b>sqlite3_value_text16le</b><td>&rarr;<td>UTF-16le TEXT value
5520 ** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
5521 ** <tr><td><b>sqlite3_value_bytes</b><td>&rarr;<td>Size of a BLOB
5522 ** or a UTF-8 TEXT in bytes
5523 ** <tr><td><b>sqlite3_value_bytes16&nbsp;&nbsp;</b>
5524 ** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
5525 ** TEXT in bytes
5526 ** <tr><td><b>sqlite3_value_type</b><td>&rarr;<td>Default
5527 ** datatype of the value
5528 ** <tr><td><b>sqlite3_value_numeric_type&nbsp;&nbsp;</b>
5529 ** <td>&rarr;&nbsp;&nbsp;<td>Best numeric datatype of the value
5530 ** <tr><td><b>sqlite3_value_nochange&nbsp;&nbsp;</b>
5531 ** <td>&rarr;&nbsp;&nbsp;<td>True if the column is unchanged in an UPDATE
5532 ** against a virtual table.
5533 ** <tr><td><b>sqlite3_value_frombind&nbsp;&nbsp;</b>
5534 ** <td>&rarr;&nbsp;&nbsp;<td>True if value originated from a [bound parameter]
5535 ** </table></blockquote>
5536 **
5537 ** <b>Details:</b>
5538 **
5539 ** These routines extract type, size, and content information from
5540 ** [protected sqlite3_value] objects.  Protected sqlite3_value objects
5541 ** are used to pass parameter information into the functions that
5542 ** implement [application-defined SQL functions] and [virtual tables].
5543 **
5544 ** These routines work only with [protected sqlite3_value] objects.
5545 ** Any attempt to use these routines on an [unprotected sqlite3_value]
5546 ** is not threadsafe.
5547 **
5548 ** ^These routines work just like the corresponding [column access functions]
5549 ** except that these routines take a single [protected sqlite3_value] object
5550 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
5551 **
5552 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
5553 ** in the native byte-order of the host machine.  ^The
5554 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
5555 ** extract UTF-16 strings as big-endian and little-endian respectively.
5556 **
5557 ** ^If [sqlite3_value] object V was initialized
5558 ** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
5559 ** and if X and Y are strings that compare equal according to strcmp(X,Y),
5560 ** then sqlite3_value_pointer(V,Y) will return the pointer P.  ^Otherwise,
5561 ** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
5562 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5563 **
5564 ** ^(The sqlite3_value_type(V) interface returns the
5565 ** [SQLITE_INTEGER | datatype code] for the initial datatype of the
5566 ** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
5567 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
5568 ** Other interfaces might change the datatype for an sqlite3_value object.
5569 ** For example, if the datatype is initially SQLITE_INTEGER and
5570 ** sqlite3_value_text(V) is called to extract a text value for that
5571 ** integer, then subsequent calls to sqlite3_value_type(V) might return
5572 ** SQLITE_TEXT.  Whether or not a persistent internal datatype conversion
5573 ** occurs is undefined and may change from one release of SQLite to the next.
5574 **
5575 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
5576 ** numeric affinity to the value.  This means that an attempt is
5577 ** made to convert the value to an integer or floating point.  If
5578 ** such a conversion is possible without loss of information (in other
5579 ** words, if the value is a string that looks like a number)
5580 ** then the conversion is performed.  Otherwise no conversion occurs.
5581 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
5582 **
5583 ** ^Within the [xUpdate] method of a [virtual table], the
5584 ** sqlite3_value_nochange(X) interface returns true if and only if
5585 ** the column corresponding to X is unchanged by the UPDATE operation
5586 ** that the xUpdate method call was invoked to implement and if
5587 ** and the prior [xColumn] method call that was invoked to extracted
5588 ** the value for that column returned without setting a result (probably
5589 ** because it queried [sqlite3_vtab_nochange()] and found that the column
5590 ** was unchanging).  ^Within an [xUpdate] method, any value for which
5591 ** sqlite3_value_nochange(X) is true will in all other respects appear
5592 ** to be a NULL value.  If sqlite3_value_nochange(X) is invoked anywhere other
5593 ** than within an [xUpdate] method call for an UPDATE statement, then
5594 ** the return value is arbitrary and meaningless.
5595 **
5596 ** ^The sqlite3_value_frombind(X) interface returns non-zero if the
5597 ** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()]
5598 ** interfaces.  ^If X comes from an SQL literal value, or a table column,
5599 ** or an expression, then sqlite3_value_frombind(X) returns zero.
5600 **
5601 ** Please pay particular attention to the fact that the pointer returned
5602 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
5603 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
5604 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
5605 ** or [sqlite3_value_text16()].
5606 **
5607 ** These routines must be called from the same thread as
5608 ** the SQL function that supplied the [sqlite3_value*] parameters.
5609 **
5610 ** As long as the input parameter is correct, these routines can only
5611 ** fail if an out-of-memory error occurs during a format conversion.
5612 ** Only the following subset of interfaces are subject to out-of-memory
5613 ** errors:
5614 **
5615 ** <ul>
5616 ** <li> sqlite3_value_blob()
5617 ** <li> sqlite3_value_text()
5618 ** <li> sqlite3_value_text16()
5619 ** <li> sqlite3_value_text16le()
5620 ** <li> sqlite3_value_text16be()
5621 ** <li> sqlite3_value_bytes()
5622 ** <li> sqlite3_value_bytes16()
5623 ** </ul>
5624 **
5625 ** If an out-of-memory error occurs, then the return value from these
5626 ** routines is the same as if the column had contained an SQL NULL value.
5627 ** Valid SQL NULL returns can be distinguished from out-of-memory errors
5628 ** by invoking the [sqlite3_errcode()] immediately after the suspect
5629 ** return value is obtained and before any
5630 ** other SQLite interface is called on the same [database connection].
5631 */
5632 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
5633 SQLITE_API double sqlite3_value_double(sqlite3_value*);
5634 SQLITE_API int sqlite3_value_int(sqlite3_value*);
5635 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
5636 SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
5637 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
5638 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
5639 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
5640 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
5641 SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
5642 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
5643 SQLITE_API int sqlite3_value_type(sqlite3_value*);
5644 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
5645 SQLITE_API int sqlite3_value_nochange(sqlite3_value*);
5646 SQLITE_API int sqlite3_value_frombind(sqlite3_value*);
5647 
5648 /*
5649 ** CAPI3REF: Report the internal text encoding state of an sqlite3_value object
5650 ** METHOD: sqlite3_value
5651 **
5652 ** ^(The sqlite3_value_encoding(X) interface returns one of [SQLITE_UTF8],
5653 ** [SQLITE_UTF16BE], or [SQLITE_UTF16LE] according to the current text encoding
5654 ** of the value X, assuming that X has type TEXT.)^  If sqlite3_value_type(X)
5655 ** returns something other than SQLITE_TEXT, then the return value from
5656 ** sqlite3_value_encoding(X) is meaningless.  ^Calls to
5657 ** [sqlite3_value_text(X)], [sqlite3_value_text16(X)], [sqlite3_value_text16be(X)],
5658 ** [sqlite3_value_text16le(X)], [sqlite3_value_bytes(X)], or
5659 ** [sqlite3_value_bytes16(X)] might change the encoding of the value X and
5660 ** thus change the return from subsequent calls to sqlite3_value_encoding(X).
5661 **
5662 ** This routine is intended for used by applications that test and validate
5663 ** the SQLite implementation.  This routine is inquiring about the opaque
5664 ** internal state of an [sqlite3_value] object.  Ordinary applications should
5665 ** not need to know what the internal state of an sqlite3_value object is and
5666 ** hence should not need to use this interface.
5667 */
5668 SQLITE_API int sqlite3_value_encoding(sqlite3_value*);
5669 
5670 /*
5671 ** CAPI3REF: Finding The Subtype Of SQL Values
5672 ** METHOD: sqlite3_value
5673 **
5674 ** The sqlite3_value_subtype(V) function returns the subtype for
5675 ** an [application-defined SQL function] argument V.  The subtype
5676 ** information can be used to pass a limited amount of context from
5677 ** one SQL function to another.  Use the [sqlite3_result_subtype()]
5678 ** routine to set the subtype for the return value of an SQL function.
5679 */
5680 SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
5681 
5682 /*
5683 ** CAPI3REF: Copy And Free SQL Values
5684 ** METHOD: sqlite3_value
5685 **
5686 ** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
5687 ** object D and returns a pointer to that copy.  ^The [sqlite3_value] returned
5688 ** is a [protected sqlite3_value] object even if the input is not.
5689 ** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
5690 ** memory allocation fails. ^If V is a [pointer value], then the result
5691 ** of sqlite3_value_dup(V) is a NULL value.
5692 **
5693 ** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
5694 ** previously obtained from [sqlite3_value_dup()].  ^If V is a NULL pointer
5695 ** then sqlite3_value_free(V) is a harmless no-op.
5696 */
5697 SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
5698 SQLITE_API void sqlite3_value_free(sqlite3_value*);
5699 
5700 /*
5701 ** CAPI3REF: Obtain Aggregate Function Context
5702 ** METHOD: sqlite3_context
5703 **
5704 ** Implementations of aggregate SQL functions use this
5705 ** routine to allocate memory for storing their state.
5706 **
5707 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
5708 ** for a particular aggregate function, SQLite allocates
5709 ** N bytes of memory, zeroes out that memory, and returns a pointer
5710 ** to the new memory. ^On second and subsequent calls to
5711 ** sqlite3_aggregate_context() for the same aggregate function instance,
5712 ** the same buffer is returned.  Sqlite3_aggregate_context() is normally
5713 ** called once for each invocation of the xStep callback and then one
5714 ** last time when the xFinal callback is invoked.  ^(When no rows match
5715 ** an aggregate query, the xStep() callback of the aggregate function
5716 ** implementation is never called and xFinal() is called exactly once.
5717 ** In those cases, sqlite3_aggregate_context() might be called for the
5718 ** first time from within xFinal().)^
5719 **
5720 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
5721 ** when first called if N is less than or equal to zero or if a memory
5722 ** allocation error occurs.
5723 **
5724 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
5725 ** determined by the N parameter on first successful call.  Changing the
5726 ** value of N in any subsequent call to sqlite3_aggregate_context() within
5727 ** the same aggregate function instance will not resize the memory
5728 ** allocation.)^  Within the xFinal callback, it is customary to set
5729 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
5730 ** pointless memory allocations occur.
5731 **
5732 ** ^SQLite automatically frees the memory allocated by
5733 ** sqlite3_aggregate_context() when the aggregate query concludes.
5734 **
5735 ** The first parameter must be a copy of the
5736 ** [sqlite3_context | SQL function context] that is the first parameter
5737 ** to the xStep or xFinal callback routine that implements the aggregate
5738 ** function.
5739 **
5740 ** This routine must be called from the same thread in which
5741 ** the aggregate SQL function is running.
5742 */
5743 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
5744 
5745 /*
5746 ** CAPI3REF: User Data For Functions
5747 ** METHOD: sqlite3_context
5748 **
5749 ** ^The sqlite3_user_data() interface returns a copy of
5750 ** the pointer that was the pUserData parameter (the 5th parameter)
5751 ** of the [sqlite3_create_function()]
5752 ** and [sqlite3_create_function16()] routines that originally
5753 ** registered the application defined function.
5754 **
5755 ** This routine must be called from the same thread in which
5756 ** the application-defined function is running.
5757 */
5758 SQLITE_API void *sqlite3_user_data(sqlite3_context*);
5759 
5760 /*
5761 ** CAPI3REF: Database Connection For Functions
5762 ** METHOD: sqlite3_context
5763 **
5764 ** ^The sqlite3_context_db_handle() interface returns a copy of
5765 ** the pointer to the [database connection] (the 1st parameter)
5766 ** of the [sqlite3_create_function()]
5767 ** and [sqlite3_create_function16()] routines that originally
5768 ** registered the application defined function.
5769 */
5770 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
5771 
5772 /*
5773 ** CAPI3REF: Function Auxiliary Data
5774 ** METHOD: sqlite3_context
5775 **
5776 ** These functions may be used by (non-aggregate) SQL functions to
5777 ** associate metadata with argument values. If the same value is passed to
5778 ** multiple invocations of the same SQL function during query execution, under
5779 ** some circumstances the associated metadata may be preserved.  An example
5780 ** of where this might be useful is in a regular-expression matching
5781 ** function. The compiled version of the regular expression can be stored as
5782 ** metadata associated with the pattern string.
5783 ** Then as long as the pattern string remains the same,
5784 ** the compiled regular expression can be reused on multiple
5785 ** invocations of the same function.
5786 **
5787 ** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata
5788 ** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
5789 ** value to the application-defined function.  ^N is zero for the left-most
5790 ** function argument.  ^If there is no metadata
5791 ** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
5792 ** returns a NULL pointer.
5793 **
5794 ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
5795 ** argument of the application-defined function.  ^Subsequent
5796 ** calls to sqlite3_get_auxdata(C,N) return P from the most recent
5797 ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
5798 ** NULL if the metadata has been discarded.
5799 ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
5800 ** SQLite will invoke the destructor function X with parameter P exactly
5801 ** once, when the metadata is discarded.
5802 ** SQLite is free to discard the metadata at any time, including: <ul>
5803 ** <li> ^(when the corresponding function parameter changes)^, or
5804 ** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
5805 **      SQL statement)^, or
5806 ** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
5807 **       parameter)^, or
5808 ** <li> ^(during the original sqlite3_set_auxdata() call when a memory
5809 **      allocation error occurs.)^ </ul>
5810 **
5811 ** Note the last bullet in particular.  The destructor X in
5812 ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
5813 ** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
5814 ** should be called near the end of the function implementation and the
5815 ** function implementation should not make any use of P after
5816 ** sqlite3_set_auxdata() has been called.
5817 **
5818 ** ^(In practice, metadata is preserved between function calls for
5819 ** function parameters that are compile-time constants, including literal
5820 ** values and [parameters] and expressions composed from the same.)^
5821 **
5822 ** The value of the N parameter to these interfaces should be non-negative.
5823 ** Future enhancements may make use of negative N values to define new
5824 ** kinds of function caching behavior.
5825 **
5826 ** These routines must be called from the same thread in which
5827 ** the SQL function is running.
5828 */
5829 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
5830 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
5831 
5832 
5833 /*
5834 ** CAPI3REF: Constants Defining Special Destructor Behavior
5835 **
5836 ** These are special values for the destructor that is passed in as the
5837 ** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
5838 ** argument is SQLITE_STATIC, it means that the content pointer is constant
5839 ** and will never change.  It does not need to be destroyed.  ^The
5840 ** SQLITE_TRANSIENT value means that the content will likely change in
5841 ** the near future and that SQLite should make its own private copy of
5842 ** the content before returning.
5843 **
5844 ** The typedef is necessary to work around problems in certain
5845 ** C++ compilers.
5846 */
5847 typedef void (*sqlite3_destructor_type)(void*);
5848 #define SQLITE_STATIC      ((sqlite3_destructor_type)0)
5849 #define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
5850 
5851 /*
5852 ** CAPI3REF: Setting The Result Of An SQL Function
5853 ** METHOD: sqlite3_context
5854 **
5855 ** These routines are used by the xFunc or xFinal callbacks that
5856 ** implement SQL functions and aggregates.  See
5857 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
5858 ** for additional information.
5859 **
5860 ** These functions work very much like the [parameter binding] family of
5861 ** functions used to bind values to host parameters in prepared statements.
5862 ** Refer to the [SQL parameter] documentation for additional information.
5863 **
5864 ** ^The sqlite3_result_blob() interface sets the result from
5865 ** an application-defined function to be the BLOB whose content is pointed
5866 ** to by the second parameter and which is N bytes long where N is the
5867 ** third parameter.
5868 **
5869 ** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
5870 ** interfaces set the result of the application-defined function to be
5871 ** a BLOB containing all zero bytes and N bytes in size.
5872 **
5873 ** ^The sqlite3_result_double() interface sets the result from
5874 ** an application-defined function to be a floating point value specified
5875 ** by its 2nd argument.
5876 **
5877 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
5878 ** cause the implemented SQL function to throw an exception.
5879 ** ^SQLite uses the string pointed to by the
5880 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
5881 ** as the text of an error message.  ^SQLite interprets the error
5882 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
5883 ** interprets the string from sqlite3_result_error16() as UTF-16 using
5884 ** the same [byte-order determination rules] as [sqlite3_bind_text16()].
5885 ** ^If the third parameter to sqlite3_result_error()
5886 ** or sqlite3_result_error16() is negative then SQLite takes as the error
5887 ** message all text up through the first zero character.
5888 ** ^If the third parameter to sqlite3_result_error() or
5889 ** sqlite3_result_error16() is non-negative then SQLite takes that many
5890 ** bytes (not characters) from the 2nd parameter as the error message.
5891 ** ^The sqlite3_result_error() and sqlite3_result_error16()
5892 ** routines make a private copy of the error message text before
5893 ** they return.  Hence, the calling function can deallocate or
5894 ** modify the text after they return without harm.
5895 ** ^The sqlite3_result_error_code() function changes the error code
5896 ** returned by SQLite as a result of an error in a function.  ^By default,
5897 ** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
5898 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
5899 **
5900 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
5901 ** error indicating that a string or BLOB is too long to represent.
5902 **
5903 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
5904 ** error indicating that a memory allocation failed.
5905 **
5906 ** ^The sqlite3_result_int() interface sets the return value
5907 ** of the application-defined function to be the 32-bit signed integer
5908 ** value given in the 2nd argument.
5909 ** ^The sqlite3_result_int64() interface sets the return value
5910 ** of the application-defined function to be the 64-bit signed integer
5911 ** value given in the 2nd argument.
5912 **
5913 ** ^The sqlite3_result_null() interface sets the return value
5914 ** of the application-defined function to be NULL.
5915 **
5916 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
5917 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
5918 ** set the return value of the application-defined function to be
5919 ** a text string which is represented as UTF-8, UTF-16 native byte order,
5920 ** UTF-16 little endian, or UTF-16 big endian, respectively.
5921 ** ^The sqlite3_result_text64() interface sets the return value of an
5922 ** application-defined function to be a text string in an encoding
5923 ** specified by the fifth (and last) parameter, which must be one
5924 ** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
5925 ** ^SQLite takes the text result from the application from
5926 ** the 2nd parameter of the sqlite3_result_text* interfaces.
5927 ** ^If the 3rd parameter to any of the sqlite3_result_text* interfaces
5928 ** other than sqlite3_result_text64() is negative, then SQLite computes
5929 ** the string length itself by searching the 2nd parameter for the first
5930 ** zero character.
5931 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5932 ** is non-negative, then as many bytes (not characters) of the text
5933 ** pointed to by the 2nd parameter are taken as the application-defined
5934 ** function result.  If the 3rd parameter is non-negative, then it
5935 ** must be the byte offset into the string where the NUL terminator would
5936 ** appear if the string where NUL terminated.  If any NUL characters occur
5937 ** in the string at a byte offset that is less than the value of the 3rd
5938 ** parameter, then the resulting string will contain embedded NULs and the
5939 ** result of expressions operating on strings with embedded NULs is undefined.
5940 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
5941 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
5942 ** function as the destructor on the text or BLOB result when it has
5943 ** finished using that result.
5944 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
5945 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
5946 ** assumes that the text or BLOB result is in constant space and does not
5947 ** copy the content of the parameter nor call a destructor on the content
5948 ** when it has finished using that result.
5949 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
5950 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
5951 ** then SQLite makes a copy of the result into space obtained
5952 ** from [sqlite3_malloc()] before it returns.
5953 **
5954 ** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and
5955 ** sqlite3_result_text16be() routines, and for sqlite3_result_text64()
5956 ** when the encoding is not UTF8, if the input UTF16 begins with a
5957 ** byte-order mark (BOM, U+FEFF) then the BOM is removed from the
5958 ** string and the rest of the string is interpreted according to the
5959 ** byte-order specified by the BOM.  ^The byte-order specified by
5960 ** the BOM at the beginning of the text overrides the byte-order
5961 ** specified by the interface procedure.  ^So, for example, if
5962 ** sqlite3_result_text16le() is invoked with text that begins
5963 ** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the
5964 ** first two bytes of input are skipped and the remaining input
5965 ** is interpreted as UTF16BE text.
5966 **
5967 ** ^For UTF16 input text to the sqlite3_result_text16(),
5968 ** sqlite3_result_text16be(), sqlite3_result_text16le(), and
5969 ** sqlite3_result_text64() routines, if the text contains invalid
5970 ** UTF16 characters, the invalid characters might be converted
5971 ** into the unicode replacement character, U+FFFD.
5972 **
5973 ** ^The sqlite3_result_value() interface sets the result of
5974 ** the application-defined function to be a copy of the
5975 ** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
5976 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
5977 ** so that the [sqlite3_value] specified in the parameter may change or
5978 ** be deallocated after sqlite3_result_value() returns without harm.
5979 ** ^A [protected sqlite3_value] object may always be used where an
5980 ** [unprotected sqlite3_value] object is required, so either
5981 ** kind of [sqlite3_value] object can be used with this interface.
5982 **
5983 ** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
5984 ** SQL NULL value, just like [sqlite3_result_null(C)], except that it
5985 ** also associates the host-language pointer P or type T with that
5986 ** NULL value such that the pointer can be retrieved within an
5987 ** [application-defined SQL function] using [sqlite3_value_pointer()].
5988 ** ^If the D parameter is not NULL, then it is a pointer to a destructor
5989 ** for the P parameter.  ^SQLite invokes D with P as its only argument
5990 ** when SQLite is finished with P.  The T parameter should be a static
5991 ** string and preferably a string literal. The sqlite3_result_pointer()
5992 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5993 **
5994 ** If these routines are called from within the different thread
5995 ** than the one containing the application-defined function that received
5996 ** the [sqlite3_context] pointer, the results are undefined.
5997 */
5998 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
5999 SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
6000                            sqlite3_uint64,void(*)(void*));
6001 SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
6002 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
6003 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
6004 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
6005 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
6006 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
6007 SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
6008 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
6009 SQLITE_API void sqlite3_result_null(sqlite3_context*);
6010 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
6011 SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
6012                            void(*)(void*), unsigned char encoding);
6013 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
6014 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
6015 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
6016 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
6017 SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
6018 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
6019 SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
6020 
6021 
6022 /*
6023 ** CAPI3REF: Setting The Subtype Of An SQL Function
6024 ** METHOD: sqlite3_context
6025 **
6026 ** The sqlite3_result_subtype(C,T) function causes the subtype of
6027 ** the result from the [application-defined SQL function] with
6028 ** [sqlite3_context] C to be the value T.  Only the lower 8 bits
6029 ** of the subtype T are preserved in current versions of SQLite;
6030 ** higher order bits are discarded.
6031 ** The number of subtype bytes preserved by SQLite might increase
6032 ** in future releases of SQLite.
6033 */
6034 SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
6035 
6036 /*
6037 ** CAPI3REF: Define New Collating Sequences
6038 ** METHOD: sqlite3
6039 **
6040 ** ^These functions add, remove, or modify a [collation] associated
6041 ** with the [database connection] specified as the first argument.
6042 **
6043 ** ^The name of the collation is a UTF-8 string
6044 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
6045 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
6046 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
6047 ** considered to be the same name.
6048 **
6049 ** ^(The third argument (eTextRep) must be one of the constants:
6050 ** <ul>
6051 ** <li> [SQLITE_UTF8],
6052 ** <li> [SQLITE_UTF16LE],
6053 ** <li> [SQLITE_UTF16BE],
6054 ** <li> [SQLITE_UTF16], or
6055 ** <li> [SQLITE_UTF16_ALIGNED].
6056 ** </ul>)^
6057 ** ^The eTextRep argument determines the encoding of strings passed
6058 ** to the collating function callback, xCompare.
6059 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
6060 ** force strings to be UTF16 with native byte order.
6061 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
6062 ** on an even byte address.
6063 **
6064 ** ^The fourth argument, pArg, is an application data pointer that is passed
6065 ** through as the first argument to the collating function callback.
6066 **
6067 ** ^The fifth argument, xCompare, is a pointer to the collating function.
6068 ** ^Multiple collating functions can be registered using the same name but
6069 ** with different eTextRep parameters and SQLite will use whichever
6070 ** function requires the least amount of data transformation.
6071 ** ^If the xCompare argument is NULL then the collating function is
6072 ** deleted.  ^When all collating functions having the same name are deleted,
6073 ** that collation is no longer usable.
6074 **
6075 ** ^The collating function callback is invoked with a copy of the pArg
6076 ** application data pointer and with two strings in the encoding specified
6077 ** by the eTextRep argument.  The two integer parameters to the collating
6078 ** function callback are the length of the two strings, in bytes. The collating
6079 ** function must return an integer that is negative, zero, or positive
6080 ** if the first string is less than, equal to, or greater than the second,
6081 ** respectively.  A collating function must always return the same answer
6082 ** given the same inputs.  If two or more collating functions are registered
6083 ** to the same collation name (using different eTextRep values) then all
6084 ** must give an equivalent answer when invoked with equivalent strings.
6085 ** The collating function must obey the following properties for all
6086 ** strings A, B, and C:
6087 **
6088 ** <ol>
6089 ** <li> If A==B then B==A.
6090 ** <li> If A==B and B==C then A==C.
6091 ** <li> If A&lt;B THEN B&gt;A.
6092 ** <li> If A&lt;B and B&lt;C then A&lt;C.
6093 ** </ol>
6094 **
6095 ** If a collating function fails any of the above constraints and that
6096 ** collating function is registered and used, then the behavior of SQLite
6097 ** is undefined.
6098 **
6099 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
6100 ** with the addition that the xDestroy callback is invoked on pArg when
6101 ** the collating function is deleted.
6102 ** ^Collating functions are deleted when they are overridden by later
6103 ** calls to the collation creation functions or when the
6104 ** [database connection] is closed using [sqlite3_close()].
6105 **
6106 ** ^The xDestroy callback is <u>not</u> called if the
6107 ** sqlite3_create_collation_v2() function fails.  Applications that invoke
6108 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
6109 ** check the return code and dispose of the application data pointer
6110 ** themselves rather than expecting SQLite to deal with it for them.
6111 ** This is different from every other SQLite interface.  The inconsistency
6112 ** is unfortunate but cannot be changed without breaking backwards
6113 ** compatibility.
6114 **
6115 ** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
6116 */
6117 SQLITE_API int sqlite3_create_collation(
6118   sqlite3*,
6119   const char *zName,
6120   int eTextRep,
6121   void *pArg,
6122   int(*xCompare)(void*,int,const void*,int,const void*)
6123 );
6124 SQLITE_API int sqlite3_create_collation_v2(
6125   sqlite3*,
6126   const char *zName,
6127   int eTextRep,
6128   void *pArg,
6129   int(*xCompare)(void*,int,const void*,int,const void*),
6130   void(*xDestroy)(void*)
6131 );
6132 SQLITE_API int sqlite3_create_collation16(
6133   sqlite3*,
6134   const void *zName,
6135   int eTextRep,
6136   void *pArg,
6137   int(*xCompare)(void*,int,const void*,int,const void*)
6138 );
6139 
6140 /*
6141 ** CAPI3REF: Collation Needed Callbacks
6142 ** METHOD: sqlite3
6143 **
6144 ** ^To avoid having to register all collation sequences before a database
6145 ** can be used, a single callback function may be registered with the
6146 ** [database connection] to be invoked whenever an undefined collation
6147 ** sequence is required.
6148 **
6149 ** ^If the function is registered using the sqlite3_collation_needed() API,
6150 ** then it is passed the names of undefined collation sequences as strings
6151 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
6152 ** the names are passed as UTF-16 in machine native byte order.
6153 ** ^A call to either function replaces the existing collation-needed callback.
6154 **
6155 ** ^(When the callback is invoked, the first argument passed is a copy
6156 ** of the second argument to sqlite3_collation_needed() or
6157 ** sqlite3_collation_needed16().  The second argument is the database
6158 ** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
6159 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
6160 ** sequence function required.  The fourth parameter is the name of the
6161 ** required collation sequence.)^
6162 **
6163 ** The callback function should register the desired collation using
6164 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
6165 ** [sqlite3_create_collation_v2()].
6166 */
6167 SQLITE_API int sqlite3_collation_needed(
6168   sqlite3*,
6169   void*,
6170   void(*)(void*,sqlite3*,int eTextRep,const char*)
6171 );
6172 SQLITE_API int sqlite3_collation_needed16(
6173   sqlite3*,
6174   void*,
6175   void(*)(void*,sqlite3*,int eTextRep,const void*)
6176 );
6177 
6178 #ifdef SQLITE_ENABLE_CEROD
6179 /*
6180 ** Specify the activation key for a CEROD database.  Unless
6181 ** activated, none of the CEROD routines will work.
6182 */
6183 SQLITE_API void sqlite3_activate_cerod(
6184   const char *zPassPhrase        /* Activation phrase */
6185 );
6186 #endif
6187 
6188 /*
6189 ** CAPI3REF: Suspend Execution For A Short Time
6190 **
6191 ** The sqlite3_sleep() function causes the current thread to suspend execution
6192 ** for at least a number of milliseconds specified in its parameter.
6193 **
6194 ** If the operating system does not support sleep requests with
6195 ** millisecond time resolution, then the time will be rounded up to
6196 ** the nearest second. The number of milliseconds of sleep actually
6197 ** requested from the operating system is returned.
6198 **
6199 ** ^SQLite implements this interface by calling the xSleep()
6200 ** method of the default [sqlite3_vfs] object.  If the xSleep() method
6201 ** of the default VFS is not implemented correctly, or not implemented at
6202 ** all, then the behavior of sqlite3_sleep() may deviate from the description
6203 ** in the previous paragraphs.
6204 */
6205 SQLITE_API int sqlite3_sleep(int);
6206 
6207 /*
6208 ** CAPI3REF: Name Of The Folder Holding Temporary Files
6209 **
6210 ** ^(If this global variable is made to point to a string which is
6211 ** the name of a folder (a.k.a. directory), then all temporary files
6212 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
6213 ** will be placed in that directory.)^  ^If this variable
6214 ** is a NULL pointer, then SQLite performs a search for an appropriate
6215 ** temporary file directory.
6216 **
6217 ** Applications are strongly discouraged from using this global variable.
6218 ** It is required to set a temporary folder on Windows Runtime (WinRT).
6219 ** But for all other platforms, it is highly recommended that applications
6220 ** neither read nor write this variable.  This global variable is a relic
6221 ** that exists for backwards compatibility of legacy applications and should
6222 ** be avoided in new projects.
6223 **
6224 ** It is not safe to read or modify this variable in more than one
6225 ** thread at a time.  It is not safe to read or modify this variable
6226 ** if a [database connection] is being used at the same time in a separate
6227 ** thread.
6228 ** It is intended that this variable be set once
6229 ** as part of process initialization and before any SQLite interface
6230 ** routines have been called and that this variable remain unchanged
6231 ** thereafter.
6232 **
6233 ** ^The [temp_store_directory pragma] may modify this variable and cause
6234 ** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
6235 ** the [temp_store_directory pragma] always assumes that any string
6236 ** that this variable points to is held in memory obtained from
6237 ** [sqlite3_malloc] and the pragma may attempt to free that memory
6238 ** using [sqlite3_free].
6239 ** Hence, if this variable is modified directly, either it should be
6240 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
6241 ** or else the use of the [temp_store_directory pragma] should be avoided.
6242 ** Except when requested by the [temp_store_directory pragma], SQLite
6243 ** does not free the memory that sqlite3_temp_directory points to.  If
6244 ** the application wants that memory to be freed, it must do
6245 ** so itself, taking care to only do so after all [database connection]
6246 ** objects have been destroyed.
6247 **
6248 ** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
6249 ** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
6250 ** features that require the use of temporary files may fail.  Here is an
6251 ** example of how to do this using C++ with the Windows Runtime:
6252 **
6253 ** <blockquote><pre>
6254 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
6255 ** &nbsp;     TemporaryFolder->Path->Data();
6256 ** char zPathBuf&#91;MAX_PATH + 1&#93;;
6257 ** memset(zPathBuf, 0, sizeof(zPathBuf));
6258 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
6259 ** &nbsp;     NULL, NULL);
6260 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
6261 ** </pre></blockquote>
6262 */
6263 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
6264 
6265 /*
6266 ** CAPI3REF: Name Of The Folder Holding Database Files
6267 **
6268 ** ^(If this global variable is made to point to a string which is
6269 ** the name of a folder (a.k.a. directory), then all database files
6270 ** specified with a relative pathname and created or accessed by
6271 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
6272 ** to be relative to that directory.)^ ^If this variable is a NULL
6273 ** pointer, then SQLite assumes that all database files specified
6274 ** with a relative pathname are relative to the current directory
6275 ** for the process.  Only the windows VFS makes use of this global
6276 ** variable; it is ignored by the unix VFS.
6277 **
6278 ** Changing the value of this variable while a database connection is
6279 ** open can result in a corrupt database.
6280 **
6281 ** It is not safe to read or modify this variable in more than one
6282 ** thread at a time.  It is not safe to read or modify this variable
6283 ** if a [database connection] is being used at the same time in a separate
6284 ** thread.
6285 ** It is intended that this variable be set once
6286 ** as part of process initialization and before any SQLite interface
6287 ** routines have been called and that this variable remain unchanged
6288 ** thereafter.
6289 **
6290 ** ^The [data_store_directory pragma] may modify this variable and cause
6291 ** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
6292 ** the [data_store_directory pragma] always assumes that any string
6293 ** that this variable points to is held in memory obtained from
6294 ** [sqlite3_malloc] and the pragma may attempt to free that memory
6295 ** using [sqlite3_free].
6296 ** Hence, if this variable is modified directly, either it should be
6297 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
6298 ** or else the use of the [data_store_directory pragma] should be avoided.
6299 */
6300 SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
6301 
6302 /*
6303 ** CAPI3REF: Win32 Specific Interface
6304 **
6305 ** These interfaces are available only on Windows.  The
6306 ** [sqlite3_win32_set_directory] interface is used to set the value associated
6307 ** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
6308 ** zValue, depending on the value of the type parameter.  The zValue parameter
6309 ** should be NULL to cause the previous value to be freed via [sqlite3_free];
6310 ** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
6311 ** prior to being used.  The [sqlite3_win32_set_directory] interface returns
6312 ** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
6313 ** or [SQLITE_NOMEM] if memory could not be allocated.  The value of the
6314 ** [sqlite3_data_directory] variable is intended to act as a replacement for
6315 ** the current directory on the sub-platforms of Win32 where that concept is
6316 ** not present, e.g. WinRT and UWP.  The [sqlite3_win32_set_directory8] and
6317 ** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
6318 ** sqlite3_win32_set_directory interface except the string parameter must be
6319 ** UTF-8 or UTF-16, respectively.
6320 */
6321 SQLITE_API int sqlite3_win32_set_directory(
6322   unsigned long type, /* Identifier for directory being set or reset */
6323   void *zValue        /* New value for directory being set or reset */
6324 );
6325 SQLITE_API int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
6326 SQLITE_API int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
6327 
6328 /*
6329 ** CAPI3REF: Win32 Directory Types
6330 **
6331 ** These macros are only available on Windows.  They define the allowed values
6332 ** for the type argument to the [sqlite3_win32_set_directory] interface.
6333 */
6334 #define SQLITE_WIN32_DATA_DIRECTORY_TYPE  1
6335 #define SQLITE_WIN32_TEMP_DIRECTORY_TYPE  2
6336 
6337 /*
6338 ** CAPI3REF: Test For Auto-Commit Mode
6339 ** KEYWORDS: {autocommit mode}
6340 ** METHOD: sqlite3
6341 **
6342 ** ^The sqlite3_get_autocommit() interface returns non-zero or
6343 ** zero if the given database connection is or is not in autocommit mode,
6344 ** respectively.  ^Autocommit mode is on by default.
6345 ** ^Autocommit mode is disabled by a [BEGIN] statement.
6346 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
6347 **
6348 ** If certain kinds of errors occur on a statement within a multi-statement
6349 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
6350 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
6351 ** transaction might be rolled back automatically.  The only way to
6352 ** find out whether SQLite automatically rolled back the transaction after
6353 ** an error is to use this function.
6354 **
6355 ** If another thread changes the autocommit status of the database
6356 ** connection while this routine is running, then the return value
6357 ** is undefined.
6358 */
6359 SQLITE_API int sqlite3_get_autocommit(sqlite3*);
6360 
6361 /*
6362 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
6363 ** METHOD: sqlite3_stmt
6364 **
6365 ** ^The sqlite3_db_handle interface returns the [database connection] handle
6366 ** to which a [prepared statement] belongs.  ^The [database connection]
6367 ** returned by sqlite3_db_handle is the same [database connection]
6368 ** that was the first argument
6369 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
6370 ** create the statement in the first place.
6371 */
6372 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
6373 
6374 /*
6375 ** CAPI3REF: Return The Schema Name For A Database Connection
6376 ** METHOD: sqlite3
6377 **
6378 ** ^The sqlite3_db_name(D,N) interface returns a pointer to the schema name
6379 ** for the N-th database on database connection D, or a NULL pointer of N is
6380 ** out of range.  An N value of 0 means the main database file.  An N of 1 is
6381 ** the "temp" schema.  Larger values of N correspond to various ATTACH-ed
6382 ** databases.
6383 **
6384 ** Space to hold the string that is returned by sqlite3_db_name() is managed
6385 ** by SQLite itself.  The string might be deallocated by any operation that
6386 ** changes the schema, including [ATTACH] or [DETACH] or calls to
6387 ** [sqlite3_serialize()] or [sqlite3_deserialize()], even operations that
6388 ** occur on a different thread.  Applications that need to
6389 ** remember the string long-term should make their own copy.  Applications that
6390 ** are accessing the same database connection simultaneously on multiple
6391 ** threads should mutex-protect calls to this API and should make their own
6392 ** private copy of the result prior to releasing the mutex.
6393 */
6394 SQLITE_API const char *sqlite3_db_name(sqlite3 *db, int N);
6395 
6396 /*
6397 ** CAPI3REF: Return The Filename For A Database Connection
6398 ** METHOD: sqlite3
6399 **
6400 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename
6401 ** associated with database N of connection D.
6402 ** ^If there is no attached database N on the database
6403 ** connection D, or if database N is a temporary or in-memory database, then
6404 ** this function will return either a NULL pointer or an empty string.
6405 **
6406 ** ^The string value returned by this routine is owned and managed by
6407 ** the database connection.  ^The value will be valid until the database N
6408 ** is [DETACH]-ed or until the database connection closes.
6409 **
6410 ** ^The filename returned by this function is the output of the
6411 ** xFullPathname method of the [VFS].  ^In other words, the filename
6412 ** will be an absolute pathname, even if the filename used
6413 ** to open the database originally was a URI or relative pathname.
6414 **
6415 ** If the filename pointer returned by this routine is not NULL, then it
6416 ** can be used as the filename input parameter to these routines:
6417 ** <ul>
6418 ** <li> [sqlite3_uri_parameter()]
6419 ** <li> [sqlite3_uri_boolean()]
6420 ** <li> [sqlite3_uri_int64()]
6421 ** <li> [sqlite3_filename_database()]
6422 ** <li> [sqlite3_filename_journal()]
6423 ** <li> [sqlite3_filename_wal()]
6424 ** </ul>
6425 */
6426 SQLITE_API sqlite3_filename sqlite3_db_filename(sqlite3 *db, const char *zDbName);
6427 
6428 /*
6429 ** CAPI3REF: Determine if a database is read-only
6430 ** METHOD: sqlite3
6431 **
6432 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
6433 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
6434 ** the name of a database on connection D.
6435 */
6436 SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
6437 
6438 /*
6439 ** CAPI3REF: Determine the transaction state of a database
6440 ** METHOD: sqlite3
6441 **
6442 ** ^The sqlite3_txn_state(D,S) interface returns the current
6443 ** [transaction state] of schema S in database connection D.  ^If S is NULL,
6444 ** then the highest transaction state of any schema on database connection D
6445 ** is returned.  Transaction states are (in order of lowest to highest):
6446 ** <ol>
6447 ** <li value="0"> SQLITE_TXN_NONE
6448 ** <li value="1"> SQLITE_TXN_READ
6449 ** <li value="2"> SQLITE_TXN_WRITE
6450 ** </ol>
6451 ** ^If the S argument to sqlite3_txn_state(D,S) is not the name of
6452 ** a valid schema, then -1 is returned.
6453 */
6454 SQLITE_API int sqlite3_txn_state(sqlite3*,const char *zSchema);
6455 
6456 /*
6457 ** CAPI3REF: Allowed return values from [sqlite3_txn_state()]
6458 ** KEYWORDS: {transaction state}
6459 **
6460 ** These constants define the current transaction state of a database file.
6461 ** ^The [sqlite3_txn_state(D,S)] interface returns one of these
6462 ** constants in order to describe the transaction state of schema S
6463 ** in [database connection] D.
6464 **
6465 ** <dl>
6466 ** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt>
6467 ** <dd>The SQLITE_TXN_NONE state means that no transaction is currently
6468 ** pending.</dd>
6469 **
6470 ** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt>
6471 ** <dd>The SQLITE_TXN_READ state means that the database is currently
6472 ** in a read transaction.  Content has been read from the database file
6473 ** but nothing in the database file has changed.  The transaction state
6474 ** will advanced to SQLITE_TXN_WRITE if any changes occur and there are
6475 ** no other conflicting concurrent write transactions.  The transaction
6476 ** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or
6477 ** [COMMIT].</dd>
6478 **
6479 ** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt>
6480 ** <dd>The SQLITE_TXN_WRITE state means that the database is currently
6481 ** in a write transaction.  Content has been written to the database file
6482 ** but has not yet committed.  The transaction state will change to
6483 ** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd>
6484 */
6485 #define SQLITE_TXN_NONE  0
6486 #define SQLITE_TXN_READ  1
6487 #define SQLITE_TXN_WRITE 2
6488 
6489 /*
6490 ** CAPI3REF: Find the next prepared statement
6491 ** METHOD: sqlite3
6492 **
6493 ** ^This interface returns a pointer to the next [prepared statement] after
6494 ** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
6495 ** then this interface returns a pointer to the first prepared statement
6496 ** associated with the database connection pDb.  ^If no prepared statement
6497 ** satisfies the conditions of this routine, it returns NULL.
6498 **
6499 ** The [database connection] pointer D in a call to
6500 ** [sqlite3_next_stmt(D,S)] must refer to an open database
6501 ** connection and in particular must not be a NULL pointer.
6502 */
6503 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
6504 
6505 /*
6506 ** CAPI3REF: Commit And Rollback Notification Callbacks
6507 ** METHOD: sqlite3
6508 **
6509 ** ^The sqlite3_commit_hook() interface registers a callback
6510 ** function to be invoked whenever a transaction is [COMMIT | committed].
6511 ** ^Any callback set by a previous call to sqlite3_commit_hook()
6512 ** for the same database connection is overridden.
6513 ** ^The sqlite3_rollback_hook() interface registers a callback
6514 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
6515 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
6516 ** for the same database connection is overridden.
6517 ** ^The pArg argument is passed through to the callback.
6518 ** ^If the callback on a commit hook function returns non-zero,
6519 ** then the commit is converted into a rollback.
6520 **
6521 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
6522 ** return the P argument from the previous call of the same function
6523 ** on the same [database connection] D, or NULL for
6524 ** the first call for each function on D.
6525 **
6526 ** The commit and rollback hook callbacks are not reentrant.
6527 ** The callback implementation must not do anything that will modify
6528 ** the database connection that invoked the callback.  Any actions
6529 ** to modify the database connection must be deferred until after the
6530 ** completion of the [sqlite3_step()] call that triggered the commit
6531 ** or rollback hook in the first place.
6532 ** Note that running any other SQL statements, including SELECT statements,
6533 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
6534 ** the database connections for the meaning of "modify" in this paragraph.
6535 **
6536 ** ^Registering a NULL function disables the callback.
6537 **
6538 ** ^When the commit hook callback routine returns zero, the [COMMIT]
6539 ** operation is allowed to continue normally.  ^If the commit hook
6540 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
6541 ** ^The rollback hook is invoked on a rollback that results from a commit
6542 ** hook returning non-zero, just as it would be with any other rollback.
6543 **
6544 ** ^For the purposes of this API, a transaction is said to have been
6545 ** rolled back if an explicit "ROLLBACK" statement is executed, or
6546 ** an error or constraint causes an implicit rollback to occur.
6547 ** ^The rollback callback is not invoked if a transaction is
6548 ** automatically rolled back because the database connection is closed.
6549 **
6550 ** See also the [sqlite3_update_hook()] interface.
6551 */
6552 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
6553 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
6554 
6555 /*
6556 ** CAPI3REF: Autovacuum Compaction Amount Callback
6557 ** METHOD: sqlite3
6558 **
6559 ** ^The sqlite3_autovacuum_pages(D,C,P,X) interface registers a callback
6560 ** function C that is invoked prior to each autovacuum of the database
6561 ** file.  ^The callback is passed a copy of the generic data pointer (P),
6562 ** the schema-name of the attached database that is being autovacuumed,
6563 ** the size of the database file in pages, the number of free pages,
6564 ** and the number of bytes per page, respectively.  The callback should
6565 ** return the number of free pages that should be removed by the
6566 ** autovacuum.  ^If the callback returns zero, then no autovacuum happens.
6567 ** ^If the value returned is greater than or equal to the number of
6568 ** free pages, then a complete autovacuum happens.
6569 **
6570 ** <p>^If there are multiple ATTACH-ed database files that are being
6571 ** modified as part of a transaction commit, then the autovacuum pages
6572 ** callback is invoked separately for each file.
6573 **
6574 ** <p><b>The callback is not reentrant.</b> The callback function should
6575 ** not attempt to invoke any other SQLite interface.  If it does, bad
6576 ** things may happen, including segmentation faults and corrupt database
6577 ** files.  The callback function should be a simple function that
6578 ** does some arithmetic on its input parameters and returns a result.
6579 **
6580 ** ^The X parameter to sqlite3_autovacuum_pages(D,C,P,X) is an optional
6581 ** destructor for the P parameter.  ^If X is not NULL, then X(P) is
6582 ** invoked whenever the database connection closes or when the callback
6583 ** is overwritten by another invocation of sqlite3_autovacuum_pages().
6584 **
6585 ** <p>^There is only one autovacuum pages callback per database connection.
6586 ** ^Each call to the sqlite3_autovacuum_pages() interface overrides all
6587 ** previous invocations for that database connection.  ^If the callback
6588 ** argument (C) to sqlite3_autovacuum_pages(D,C,P,X) is a NULL pointer,
6589 ** then the autovacuum steps callback is cancelled.  The return value
6590 ** from sqlite3_autovacuum_pages() is normally SQLITE_OK, but might
6591 ** be some other error code if something goes wrong.  The current
6592 ** implementation will only return SQLITE_OK or SQLITE_MISUSE, but other
6593 ** return codes might be added in future releases.
6594 **
6595 ** <p>If no autovacuum pages callback is specified (the usual case) or
6596 ** a NULL pointer is provided for the callback,
6597 ** then the default behavior is to vacuum all free pages.  So, in other
6598 ** words, the default behavior is the same as if the callback function
6599 ** were something like this:
6600 **
6601 ** <blockquote><pre>
6602 ** &nbsp;   unsigned int demonstration_autovac_pages_callback(
6603 ** &nbsp;     void *pClientData,
6604 ** &nbsp;     const char *zSchema,
6605 ** &nbsp;     unsigned int nDbPage,
6606 ** &nbsp;     unsigned int nFreePage,
6607 ** &nbsp;     unsigned int nBytePerPage
6608 ** &nbsp;   ){
6609 ** &nbsp;     return nFreePage;
6610 ** &nbsp;   }
6611 ** </pre></blockquote>
6612 */
6613 SQLITE_API int sqlite3_autovacuum_pages(
6614   sqlite3 *db,
6615   unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
6616   void*,
6617   void(*)(void*)
6618 );
6619 
6620 
6621 /*
6622 ** CAPI3REF: Data Change Notification Callbacks
6623 ** METHOD: sqlite3
6624 **
6625 ** ^The sqlite3_update_hook() interface registers a callback function
6626 ** with the [database connection] identified by the first argument
6627 ** to be invoked whenever a row is updated, inserted or deleted in
6628 ** a [rowid table].
6629 ** ^Any callback set by a previous call to this function
6630 ** for the same database connection is overridden.
6631 **
6632 ** ^The second argument is a pointer to the function to invoke when a
6633 ** row is updated, inserted or deleted in a rowid table.
6634 ** ^The first argument to the callback is a copy of the third argument
6635 ** to sqlite3_update_hook().
6636 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
6637 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
6638 ** to be invoked.
6639 ** ^The third and fourth arguments to the callback contain pointers to the
6640 ** database and table name containing the affected row.
6641 ** ^The final callback parameter is the [rowid] of the row.
6642 ** ^In the case of an update, this is the [rowid] after the update takes place.
6643 **
6644 ** ^(The update hook is not invoked when internal system tables are
6645 ** modified (i.e. sqlite_sequence).)^
6646 ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
6647 **
6648 ** ^In the current implementation, the update hook
6649 ** is not invoked when conflicting rows are deleted because of an
6650 ** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
6651 ** invoked when rows are deleted using the [truncate optimization].
6652 ** The exceptions defined in this paragraph might change in a future
6653 ** release of SQLite.
6654 **
6655 ** The update hook implementation must not do anything that will modify
6656 ** the database connection that invoked the update hook.  Any actions
6657 ** to modify the database connection must be deferred until after the
6658 ** completion of the [sqlite3_step()] call that triggered the update hook.
6659 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
6660 ** database connections for the meaning of "modify" in this paragraph.
6661 **
6662 ** ^The sqlite3_update_hook(D,C,P) function
6663 ** returns the P argument from the previous call
6664 ** on the same [database connection] D, or NULL for
6665 ** the first call on D.
6666 **
6667 ** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
6668 ** and [sqlite3_preupdate_hook()] interfaces.
6669 */
6670 SQLITE_API void *sqlite3_update_hook(
6671   sqlite3*,
6672   void(*)(void *,int ,char const *,char const *,sqlite3_int64),
6673   void*
6674 );
6675 
6676 /*
6677 ** CAPI3REF: Enable Or Disable Shared Pager Cache
6678 **
6679 ** ^(This routine enables or disables the sharing of the database cache
6680 ** and schema data structures between [database connection | connections]
6681 ** to the same database. Sharing is enabled if the argument is true
6682 ** and disabled if the argument is false.)^
6683 **
6684 ** This interface is omitted if SQLite is compiled with
6685 ** [-DSQLITE_OMIT_SHARED_CACHE].  The [-DSQLITE_OMIT_SHARED_CACHE]
6686 ** compile-time option is recommended because the
6687 ** [use of shared cache mode is discouraged].
6688 **
6689 ** ^Cache sharing is enabled and disabled for an entire process.
6690 ** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
6691 ** In prior versions of SQLite,
6692 ** sharing was enabled or disabled for each thread separately.
6693 **
6694 ** ^(The cache sharing mode set by this interface effects all subsequent
6695 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
6696 ** Existing database connections continue to use the sharing mode
6697 ** that was in effect at the time they were opened.)^
6698 **
6699 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
6700 ** successfully.  An [error code] is returned otherwise.)^
6701 **
6702 ** ^Shared cache is disabled by default. It is recommended that it stay
6703 ** that way.  In other words, do not use this routine.  This interface
6704 ** continues to be provided for historical compatibility, but its use is
6705 ** discouraged.  Any use of shared cache is discouraged.  If shared cache
6706 ** must be used, it is recommended that shared cache only be enabled for
6707 ** individual database connections using the [sqlite3_open_v2()] interface
6708 ** with the [SQLITE_OPEN_SHAREDCACHE] flag.
6709 **
6710 ** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
6711 ** and will always return SQLITE_MISUSE. On those systems,
6712 ** shared cache mode should be enabled per-database connection via
6713 ** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
6714 **
6715 ** This interface is threadsafe on processors where writing a
6716 ** 32-bit integer is atomic.
6717 **
6718 ** See Also:  [SQLite Shared-Cache Mode]
6719 */
6720 SQLITE_API int sqlite3_enable_shared_cache(int);
6721 
6722 /*
6723 ** CAPI3REF: Attempt To Free Heap Memory
6724 **
6725 ** ^The sqlite3_release_memory() interface attempts to free N bytes
6726 ** of heap memory by deallocating non-essential memory allocations
6727 ** held by the database library.   Memory used to cache database
6728 ** pages to improve performance is an example of non-essential memory.
6729 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
6730 ** which might be more or less than the amount requested.
6731 ** ^The sqlite3_release_memory() routine is a no-op returning zero
6732 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
6733 **
6734 ** See also: [sqlite3_db_release_memory()]
6735 */
6736 SQLITE_API int sqlite3_release_memory(int);
6737 
6738 /*
6739 ** CAPI3REF: Free Memory Used By A Database Connection
6740 ** METHOD: sqlite3
6741 **
6742 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
6743 ** memory as possible from database connection D. Unlike the
6744 ** [sqlite3_release_memory()] interface, this interface is in effect even
6745 ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
6746 ** omitted.
6747 **
6748 ** See also: [sqlite3_release_memory()]
6749 */
6750 SQLITE_API int sqlite3_db_release_memory(sqlite3*);
6751 
6752 /*
6753 ** CAPI3REF: Impose A Limit On Heap Size
6754 **
6755 ** These interfaces impose limits on the amount of heap memory that will be
6756 ** by all database connections within a single process.
6757 **
6758 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
6759 ** soft limit on the amount of heap memory that may be allocated by SQLite.
6760 ** ^SQLite strives to keep heap memory utilization below the soft heap
6761 ** limit by reducing the number of pages held in the page cache
6762 ** as heap memory usages approaches the limit.
6763 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
6764 ** below the limit, it will exceed the limit rather than generate
6765 ** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
6766 ** is advisory only.
6767 **
6768 ** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of
6769 ** N bytes on the amount of memory that will be allocated.  ^The
6770 ** sqlite3_hard_heap_limit64(N) interface is similar to
6771 ** sqlite3_soft_heap_limit64(N) except that memory allocations will fail
6772 ** when the hard heap limit is reached.
6773 **
6774 ** ^The return value from both sqlite3_soft_heap_limit64() and
6775 ** sqlite3_hard_heap_limit64() is the size of
6776 ** the heap limit prior to the call, or negative in the case of an
6777 ** error.  ^If the argument N is negative
6778 ** then no change is made to the heap limit.  Hence, the current
6779 ** size of heap limits can be determined by invoking
6780 ** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1).
6781 **
6782 ** ^Setting the heap limits to zero disables the heap limiter mechanism.
6783 **
6784 ** ^The soft heap limit may not be greater than the hard heap limit.
6785 ** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N)
6786 ** is invoked with a value of N that is greater than the hard heap limit,
6787 ** the soft heap limit is set to the value of the hard heap limit.
6788 ** ^The soft heap limit is automatically enabled whenever the hard heap
6789 ** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and
6790 ** the soft heap limit is outside the range of 1..N, then the soft heap
6791 ** limit is set to N.  ^Invoking sqlite3_soft_heap_limit64(0) when the
6792 ** hard heap limit is enabled makes the soft heap limit equal to the
6793 ** hard heap limit.
6794 **
6795 ** The memory allocation limits can also be adjusted using
6796 ** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit].
6797 **
6798 ** ^(The heap limits are not enforced in the current implementation
6799 ** if one or more of following conditions are true:
6800 **
6801 ** <ul>
6802 ** <li> The limit value is set to zero.
6803 ** <li> Memory accounting is disabled using a combination of the
6804 **      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
6805 **      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
6806 ** <li> An alternative page cache implementation is specified using
6807 **      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
6808 ** <li> The page cache allocates from its own memory pool supplied
6809 **      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
6810 **      from the heap.
6811 ** </ul>)^
6812 **
6813 ** The circumstances under which SQLite will enforce the heap limits may
6814 ** changes in future releases of SQLite.
6815 */
6816 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
6817 SQLITE_API sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N);
6818 
6819 /*
6820 ** CAPI3REF: Deprecated Soft Heap Limit Interface
6821 ** DEPRECATED
6822 **
6823 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
6824 ** interface.  This routine is provided for historical compatibility
6825 ** only.  All new applications should use the
6826 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
6827 */
6828 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
6829 
6830 
6831 /*
6832 ** CAPI3REF: Extract Metadata About A Column Of A Table
6833 ** METHOD: sqlite3
6834 **
6835 ** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
6836 ** information about column C of table T in database D
6837 ** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
6838 ** interface returns SQLITE_OK and fills in the non-NULL pointers in
6839 ** the final five arguments with appropriate values if the specified
6840 ** column exists.  ^The sqlite3_table_column_metadata() interface returns
6841 ** SQLITE_ERROR if the specified column does not exist.
6842 ** ^If the column-name parameter to sqlite3_table_column_metadata() is a
6843 ** NULL pointer, then this routine simply checks for the existence of the
6844 ** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
6845 ** does not.  If the table name parameter T in a call to
6846 ** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
6847 ** undefined behavior.
6848 **
6849 ** ^The column is identified by the second, third and fourth parameters to
6850 ** this function. ^(The second parameter is either the name of the database
6851 ** (i.e. "main", "temp", or an attached database) containing the specified
6852 ** table or NULL.)^ ^If it is NULL, then all attached databases are searched
6853 ** for the table using the same algorithm used by the database engine to
6854 ** resolve unqualified table references.
6855 **
6856 ** ^The third and fourth parameters to this function are the table and column
6857 ** name of the desired column, respectively.
6858 **
6859 ** ^Metadata is returned by writing to the memory locations passed as the 5th
6860 ** and subsequent parameters to this function. ^Any of these arguments may be
6861 ** NULL, in which case the corresponding element of metadata is omitted.
6862 **
6863 ** ^(<blockquote>
6864 ** <table border="1">
6865 ** <tr><th> Parameter <th> Output<br>Type <th>  Description
6866 **
6867 ** <tr><td> 5th <td> const char* <td> Data type
6868 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
6869 ** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
6870 ** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
6871 ** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
6872 ** </table>
6873 ** </blockquote>)^
6874 **
6875 ** ^The memory pointed to by the character pointers returned for the
6876 ** declaration type and collation sequence is valid until the next
6877 ** call to any SQLite API function.
6878 **
6879 ** ^If the specified table is actually a view, an [error code] is returned.
6880 **
6881 ** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
6882 ** is not a [WITHOUT ROWID] table and an
6883 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
6884 ** parameters are set for the explicitly declared column. ^(If there is no
6885 ** [INTEGER PRIMARY KEY] column, then the outputs
6886 ** for the [rowid] are set as follows:
6887 **
6888 ** <pre>
6889 **     data type: "INTEGER"
6890 **     collation sequence: "BINARY"
6891 **     not null: 0
6892 **     primary key: 1
6893 **     auto increment: 0
6894 ** </pre>)^
6895 **
6896 ** ^This function causes all database schemas to be read from disk and
6897 ** parsed, if that has not already been done, and returns an error if
6898 ** any errors are encountered while loading the schema.
6899 */
6900 SQLITE_API int sqlite3_table_column_metadata(
6901   sqlite3 *db,                /* Connection handle */
6902   const char *zDbName,        /* Database name or NULL */
6903   const char *zTableName,     /* Table name */
6904   const char *zColumnName,    /* Column name */
6905   char const **pzDataType,    /* OUTPUT: Declared data type */
6906   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
6907   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
6908   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
6909   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
6910 );
6911 
6912 /*
6913 ** CAPI3REF: Load An Extension
6914 ** METHOD: sqlite3
6915 **
6916 ** ^This interface loads an SQLite extension library from the named file.
6917 **
6918 ** ^The sqlite3_load_extension() interface attempts to load an
6919 ** [SQLite extension] library contained in the file zFile.  If
6920 ** the file cannot be loaded directly, attempts are made to load
6921 ** with various operating-system specific extensions added.
6922 ** So for example, if "samplelib" cannot be loaded, then names like
6923 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
6924 ** be tried also.
6925 **
6926 ** ^The entry point is zProc.
6927 ** ^(zProc may be 0, in which case SQLite will try to come up with an
6928 ** entry point name on its own.  It first tries "sqlite3_extension_init".
6929 ** If that does not work, it constructs a name "sqlite3_X_init" where the
6930 ** X is consists of the lower-case equivalent of all ASCII alphabetic
6931 ** characters in the filename from the last "/" to the first following
6932 ** "." and omitting any initial "lib".)^
6933 ** ^The sqlite3_load_extension() interface returns
6934 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
6935 ** ^If an error occurs and pzErrMsg is not 0, then the
6936 ** [sqlite3_load_extension()] interface shall attempt to
6937 ** fill *pzErrMsg with error message text stored in memory
6938 ** obtained from [sqlite3_malloc()]. The calling function
6939 ** should free this memory by calling [sqlite3_free()].
6940 **
6941 ** ^Extension loading must be enabled using
6942 ** [sqlite3_enable_load_extension()] or
6943 ** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
6944 ** prior to calling this API,
6945 ** otherwise an error will be returned.
6946 **
6947 ** <b>Security warning:</b> It is recommended that the
6948 ** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
6949 ** interface.  The use of the [sqlite3_enable_load_extension()] interface
6950 ** should be avoided.  This will keep the SQL function [load_extension()]
6951 ** disabled and prevent SQL injections from giving attackers
6952 ** access to extension loading capabilities.
6953 **
6954 ** See also the [load_extension() SQL function].
6955 */
6956 SQLITE_API int sqlite3_load_extension(
6957   sqlite3 *db,          /* Load the extension into this database connection */
6958   const char *zFile,    /* Name of the shared library containing extension */
6959   const char *zProc,    /* Entry point.  Derived from zFile if 0 */
6960   char **pzErrMsg       /* Put error message here if not 0 */
6961 );
6962 
6963 /*
6964 ** CAPI3REF: Enable Or Disable Extension Loading
6965 ** METHOD: sqlite3
6966 **
6967 ** ^So as not to open security holes in older applications that are
6968 ** unprepared to deal with [extension loading], and as a means of disabling
6969 ** [extension loading] while evaluating user-entered SQL, the following API
6970 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
6971 **
6972 ** ^Extension loading is off by default.
6973 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
6974 ** to turn extension loading on and call it with onoff==0 to turn
6975 ** it back off again.
6976 **
6977 ** ^This interface enables or disables both the C-API
6978 ** [sqlite3_load_extension()] and the SQL function [load_extension()].
6979 ** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
6980 ** to enable or disable only the C-API.)^
6981 **
6982 ** <b>Security warning:</b> It is recommended that extension loading
6983 ** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
6984 ** rather than this interface, so the [load_extension()] SQL function
6985 ** remains disabled. This will prevent SQL injections from giving attackers
6986 ** access to extension loading capabilities.
6987 */
6988 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
6989 
6990 /*
6991 ** CAPI3REF: Automatically Load Statically Linked Extensions
6992 **
6993 ** ^This interface causes the xEntryPoint() function to be invoked for
6994 ** each new [database connection] that is created.  The idea here is that
6995 ** xEntryPoint() is the entry point for a statically linked [SQLite extension]
6996 ** that is to be automatically loaded into all new database connections.
6997 **
6998 ** ^(Even though the function prototype shows that xEntryPoint() takes
6999 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
7000 ** arguments and expects an integer result as if the signature of the
7001 ** entry point where as follows:
7002 **
7003 ** <blockquote><pre>
7004 ** &nbsp;  int xEntryPoint(
7005 ** &nbsp;    sqlite3 *db,
7006 ** &nbsp;    const char **pzErrMsg,
7007 ** &nbsp;    const struct sqlite3_api_routines *pThunk
7008 ** &nbsp;  );
7009 ** </pre></blockquote>)^
7010 **
7011 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
7012 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
7013 ** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
7014 ** is NULL before calling the xEntryPoint().  ^SQLite will invoke
7015 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
7016 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
7017 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
7018 **
7019 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
7020 ** on the list of automatic extensions is a harmless no-op. ^No entry point
7021 ** will be called more than once for each database connection that is opened.
7022 **
7023 ** See also: [sqlite3_reset_auto_extension()]
7024 ** and [sqlite3_cancel_auto_extension()]
7025 */
7026 SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
7027 
7028 /*
7029 ** CAPI3REF: Cancel Automatic Extension Loading
7030 **
7031 ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
7032 ** initialization routine X that was registered using a prior call to
7033 ** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
7034 ** routine returns 1 if initialization routine X was successfully
7035 ** unregistered and it returns 0 if X was not on the list of initialization
7036 ** routines.
7037 */
7038 SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
7039 
7040 /*
7041 ** CAPI3REF: Reset Automatic Extension Loading
7042 **
7043 ** ^This interface disables all automatic extensions previously
7044 ** registered using [sqlite3_auto_extension()].
7045 */
7046 SQLITE_API void sqlite3_reset_auto_extension(void);
7047 
7048 /*
7049 ** Structures used by the virtual table interface
7050 */
7051 typedef struct sqlite3_vtab sqlite3_vtab;
7052 typedef struct sqlite3_index_info sqlite3_index_info;
7053 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
7054 typedef struct sqlite3_module sqlite3_module;
7055 
7056 /*
7057 ** CAPI3REF: Virtual Table Object
7058 ** KEYWORDS: sqlite3_module {virtual table module}
7059 **
7060 ** This structure, sometimes called a "virtual table module",
7061 ** defines the implementation of a [virtual table].
7062 ** This structure consists mostly of methods for the module.
7063 **
7064 ** ^A virtual table module is created by filling in a persistent
7065 ** instance of this structure and passing a pointer to that instance
7066 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
7067 ** ^The registration remains valid until it is replaced by a different
7068 ** module or until the [database connection] closes.  The content
7069 ** of this structure must not change while it is registered with
7070 ** any database connection.
7071 */
7072 struct sqlite3_module {
7073   int iVersion;
7074   int (*xCreate)(sqlite3*, void *pAux,
7075                int argc, const char *const*argv,
7076                sqlite3_vtab **ppVTab, char**);
7077   int (*xConnect)(sqlite3*, void *pAux,
7078                int argc, const char *const*argv,
7079                sqlite3_vtab **ppVTab, char**);
7080   int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
7081   int (*xDisconnect)(sqlite3_vtab *pVTab);
7082   int (*xDestroy)(sqlite3_vtab *pVTab);
7083   int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
7084   int (*xClose)(sqlite3_vtab_cursor*);
7085   int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
7086                 int argc, sqlite3_value **argv);
7087   int (*xNext)(sqlite3_vtab_cursor*);
7088   int (*xEof)(sqlite3_vtab_cursor*);
7089   int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
7090   int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
7091   int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
7092   int (*xBegin)(sqlite3_vtab *pVTab);
7093   int (*xSync)(sqlite3_vtab *pVTab);
7094   int (*xCommit)(sqlite3_vtab *pVTab);
7095   int (*xRollback)(sqlite3_vtab *pVTab);
7096   int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
7097                        void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
7098                        void **ppArg);
7099   int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
7100   /* The methods above are in version 1 of the sqlite_module object. Those
7101   ** below are for version 2 and greater. */
7102   int (*xSavepoint)(sqlite3_vtab *pVTab, int);
7103   int (*xRelease)(sqlite3_vtab *pVTab, int);
7104   int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
7105   /* The methods above are in versions 1 and 2 of the sqlite_module object.
7106   ** Those below are for version 3 and greater. */
7107   int (*xShadowName)(const char*);
7108 };
7109 
7110 /*
7111 ** CAPI3REF: Virtual Table Indexing Information
7112 ** KEYWORDS: sqlite3_index_info
7113 **
7114 ** The sqlite3_index_info structure and its substructures is used as part
7115 ** of the [virtual table] interface to
7116 ** pass information into and receive the reply from the [xBestIndex]
7117 ** method of a [virtual table module].  The fields under **Inputs** are the
7118 ** inputs to xBestIndex and are read-only.  xBestIndex inserts its
7119 ** results into the **Outputs** fields.
7120 **
7121 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
7122 **
7123 ** <blockquote>column OP expr</blockquote>
7124 **
7125 ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
7126 ** stored in aConstraint[].op using one of the
7127 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
7128 ** ^(The index of the column is stored in
7129 ** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
7130 ** expr on the right-hand side can be evaluated (and thus the constraint
7131 ** is usable) and false if it cannot.)^
7132 **
7133 ** ^The optimizer automatically inverts terms of the form "expr OP column"
7134 ** and makes other simplifications to the WHERE clause in an attempt to
7135 ** get as many WHERE clause terms into the form shown above as possible.
7136 ** ^The aConstraint[] array only reports WHERE clause terms that are
7137 ** relevant to the particular virtual table being queried.
7138 **
7139 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
7140 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
7141 **
7142 ** The colUsed field indicates which columns of the virtual table may be
7143 ** required by the current scan. Virtual table columns are numbered from
7144 ** zero in the order in which they appear within the CREATE TABLE statement
7145 ** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
7146 ** the corresponding bit is set within the colUsed mask if the column may be
7147 ** required by SQLite. If the table has at least 64 columns and any column
7148 ** to the right of the first 63 is required, then bit 63 of colUsed is also
7149 ** set. In other words, column iCol may be required if the expression
7150 ** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
7151 ** non-zero.
7152 **
7153 ** The [xBestIndex] method must fill aConstraintUsage[] with information
7154 ** about what parameters to pass to xFilter.  ^If argvIndex>0 then
7155 ** the right-hand side of the corresponding aConstraint[] is evaluated
7156 ** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
7157 ** is true, then the constraint is assumed to be fully handled by the
7158 ** virtual table and might not be checked again by the byte code.)^ ^(The
7159 ** aConstraintUsage[].omit flag is an optimization hint. When the omit flag
7160 ** is left in its default setting of false, the constraint will always be
7161 ** checked separately in byte code.  If the omit flag is change to true, then
7162 ** the constraint may or may not be checked in byte code.  In other words,
7163 ** when the omit flag is true there is no guarantee that the constraint will
7164 ** not be checked again using byte code.)^
7165 **
7166 ** ^The idxNum and idxStr values are recorded and passed into the
7167 ** [xFilter] method.
7168 ** ^[sqlite3_free()] is used to free idxStr if and only if
7169 ** needToFreeIdxStr is true.
7170 **
7171 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
7172 ** the correct order to satisfy the ORDER BY clause so that no separate
7173 ** sorting step is required.
7174 **
7175 ** ^The estimatedCost value is an estimate of the cost of a particular
7176 ** strategy. A cost of N indicates that the cost of the strategy is similar
7177 ** to a linear scan of an SQLite table with N rows. A cost of log(N)
7178 ** indicates that the expense of the operation is similar to that of a
7179 ** binary search on a unique indexed field of an SQLite table with N rows.
7180 **
7181 ** ^The estimatedRows value is an estimate of the number of rows that
7182 ** will be returned by the strategy.
7183 **
7184 ** The xBestIndex method may optionally populate the idxFlags field with a
7185 ** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
7186 ** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
7187 ** assumes that the strategy may visit at most one row.
7188 **
7189 ** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
7190 ** SQLite also assumes that if a call to the xUpdate() method is made as
7191 ** part of the same statement to delete or update a virtual table row and the
7192 ** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
7193 ** any database changes. In other words, if the xUpdate() returns
7194 ** SQLITE_CONSTRAINT, the database contents must be exactly as they were
7195 ** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
7196 ** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
7197 ** the xUpdate method are automatically rolled back by SQLite.
7198 **
7199 ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
7200 ** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
7201 ** If a virtual table extension is
7202 ** used with an SQLite version earlier than 3.8.2, the results of attempting
7203 ** to read or write the estimatedRows field are undefined (but are likely
7204 ** to include crashing the application). The estimatedRows field should
7205 ** therefore only be used if [sqlite3_libversion_number()] returns a
7206 ** value greater than or equal to 3008002. Similarly, the idxFlags field
7207 ** was added for [version 3.9.0] ([dateof:3.9.0]).
7208 ** It may therefore only be used if
7209 ** sqlite3_libversion_number() returns a value greater than or equal to
7210 ** 3009000.
7211 */
7212 struct sqlite3_index_info {
7213   /* Inputs */
7214   int nConstraint;           /* Number of entries in aConstraint */
7215   struct sqlite3_index_constraint {
7216      int iColumn;              /* Column constrained.  -1 for ROWID */
7217      unsigned char op;         /* Constraint operator */
7218      unsigned char usable;     /* True if this constraint is usable */
7219      int iTermOffset;          /* Used internally - xBestIndex should ignore */
7220   } *aConstraint;            /* Table of WHERE clause constraints */
7221   int nOrderBy;              /* Number of terms in the ORDER BY clause */
7222   struct sqlite3_index_orderby {
7223      int iColumn;              /* Column number */
7224      unsigned char desc;       /* True for DESC.  False for ASC. */
7225   } *aOrderBy;               /* The ORDER BY clause */
7226   /* Outputs */
7227   struct sqlite3_index_constraint_usage {
7228     int argvIndex;           /* if >0, constraint is part of argv to xFilter */
7229     unsigned char omit;      /* Do not code a test for this constraint */
7230   } *aConstraintUsage;
7231   int idxNum;                /* Number used to identify the index */
7232   char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
7233   int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
7234   int orderByConsumed;       /* True if output is already ordered */
7235   double estimatedCost;           /* Estimated cost of using this index */
7236   /* Fields below are only available in SQLite 3.8.2 and later */
7237   sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
7238   /* Fields below are only available in SQLite 3.9.0 and later */
7239   int idxFlags;              /* Mask of SQLITE_INDEX_SCAN_* flags */
7240   /* Fields below are only available in SQLite 3.10.0 and later */
7241   sqlite3_uint64 colUsed;    /* Input: Mask of columns used by statement */
7242 };
7243 
7244 /*
7245 ** CAPI3REF: Virtual Table Scan Flags
7246 **
7247 ** Virtual table implementations are allowed to set the
7248 ** [sqlite3_index_info].idxFlags field to some combination of
7249 ** these bits.
7250 */
7251 #define SQLITE_INDEX_SCAN_UNIQUE      1     /* Scan visits at most 1 row */
7252 
7253 /*
7254 ** CAPI3REF: Virtual Table Constraint Operator Codes
7255 **
7256 ** These macros define the allowed values for the
7257 ** [sqlite3_index_info].aConstraint[].op field.  Each value represents
7258 ** an operator that is part of a constraint term in the WHERE clause of
7259 ** a query that uses a [virtual table].
7260 **
7261 ** ^The left-hand operand of the operator is given by the corresponding
7262 ** aConstraint[].iColumn field.  ^An iColumn of -1 indicates the left-hand
7263 ** operand is the rowid.
7264 ** The SQLITE_INDEX_CONSTRAINT_LIMIT and SQLITE_INDEX_CONSTRAINT_OFFSET
7265 ** operators have no left-hand operand, and so for those operators the
7266 ** corresponding aConstraint[].iColumn is meaningless and should not be
7267 ** used.
7268 **
7269 ** All operator values from SQLITE_INDEX_CONSTRAINT_FUNCTION through
7270 ** value 255 are reserved to represent functions that are overloaded
7271 ** by the [xFindFunction|xFindFunction method] of the virtual table
7272 ** implementation.
7273 **
7274 ** The right-hand operands for each constraint might be accessible using
7275 ** the [sqlite3_vtab_rhs_value()] interface.  Usually the right-hand
7276 ** operand is only available if it appears as a single constant literal
7277 ** in the input SQL.  If the right-hand operand is another column or an
7278 ** expression (even a constant expression) or a parameter, then the
7279 ** sqlite3_vtab_rhs_value() probably will not be able to extract it.
7280 ** ^The SQLITE_INDEX_CONSTRAINT_ISNULL and
7281 ** SQLITE_INDEX_CONSTRAINT_ISNOTNULL operators have no right-hand operand
7282 ** and hence calls to sqlite3_vtab_rhs_value() for those operators will
7283 ** always return SQLITE_NOTFOUND.
7284 **
7285 ** The collating sequence to be used for comparison can be found using
7286 ** the [sqlite3_vtab_collation()] interface.  For most real-world virtual
7287 ** tables, the collating sequence of constraints does not matter (for example
7288 ** because the constraints are numeric) and so the sqlite3_vtab_collation()
7289 ** interface is not commonly needed.
7290 */
7291 #define SQLITE_INDEX_CONSTRAINT_EQ          2
7292 #define SQLITE_INDEX_CONSTRAINT_GT          4
7293 #define SQLITE_INDEX_CONSTRAINT_LE          8
7294 #define SQLITE_INDEX_CONSTRAINT_LT         16
7295 #define SQLITE_INDEX_CONSTRAINT_GE         32
7296 #define SQLITE_INDEX_CONSTRAINT_MATCH      64
7297 #define SQLITE_INDEX_CONSTRAINT_LIKE       65
7298 #define SQLITE_INDEX_CONSTRAINT_GLOB       66
7299 #define SQLITE_INDEX_CONSTRAINT_REGEXP     67
7300 #define SQLITE_INDEX_CONSTRAINT_NE         68
7301 #define SQLITE_INDEX_CONSTRAINT_ISNOT      69
7302 #define SQLITE_INDEX_CONSTRAINT_ISNOTNULL  70
7303 #define SQLITE_INDEX_CONSTRAINT_ISNULL     71
7304 #define SQLITE_INDEX_CONSTRAINT_IS         72
7305 #define SQLITE_INDEX_CONSTRAINT_LIMIT      73
7306 #define SQLITE_INDEX_CONSTRAINT_OFFSET     74
7307 #define SQLITE_INDEX_CONSTRAINT_FUNCTION  150
7308 
7309 /*
7310 ** CAPI3REF: Register A Virtual Table Implementation
7311 ** METHOD: sqlite3
7312 **
7313 ** ^These routines are used to register a new [virtual table module] name.
7314 ** ^Module names must be registered before
7315 ** creating a new [virtual table] using the module and before using a
7316 ** preexisting [virtual table] for the module.
7317 **
7318 ** ^The module name is registered on the [database connection] specified
7319 ** by the first parameter.  ^The name of the module is given by the
7320 ** second parameter.  ^The third parameter is a pointer to
7321 ** the implementation of the [virtual table module].   ^The fourth
7322 ** parameter is an arbitrary client data pointer that is passed through
7323 ** into the [xCreate] and [xConnect] methods of the virtual table module
7324 ** when a new virtual table is be being created or reinitialized.
7325 **
7326 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
7327 ** is a pointer to a destructor for the pClientData.  ^SQLite will
7328 ** invoke the destructor function (if it is not NULL) when SQLite
7329 ** no longer needs the pClientData pointer.  ^The destructor will also
7330 ** be invoked if the call to sqlite3_create_module_v2() fails.
7331 ** ^The sqlite3_create_module()
7332 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
7333 ** destructor.
7334 **
7335 ** ^If the third parameter (the pointer to the sqlite3_module object) is
7336 ** NULL then no new module is created and any existing modules with the
7337 ** same name are dropped.
7338 **
7339 ** See also: [sqlite3_drop_modules()]
7340 */
7341 SQLITE_API int sqlite3_create_module(
7342   sqlite3 *db,               /* SQLite connection to register module with */
7343   const char *zName,         /* Name of the module */
7344   const sqlite3_module *p,   /* Methods for the module */
7345   void *pClientData          /* Client data for xCreate/xConnect */
7346 );
7347 SQLITE_API int sqlite3_create_module_v2(
7348   sqlite3 *db,               /* SQLite connection to register module with */
7349   const char *zName,         /* Name of the module */
7350   const sqlite3_module *p,   /* Methods for the module */
7351   void *pClientData,         /* Client data for xCreate/xConnect */
7352   void(*xDestroy)(void*)     /* Module destructor function */
7353 );
7354 
7355 /*
7356 ** CAPI3REF: Remove Unnecessary Virtual Table Implementations
7357 ** METHOD: sqlite3
7358 **
7359 ** ^The sqlite3_drop_modules(D,L) interface removes all virtual
7360 ** table modules from database connection D except those named on list L.
7361 ** The L parameter must be either NULL or a pointer to an array of pointers
7362 ** to strings where the array is terminated by a single NULL pointer.
7363 ** ^If the L parameter is NULL, then all virtual table modules are removed.
7364 **
7365 ** See also: [sqlite3_create_module()]
7366 */
7367 SQLITE_API int sqlite3_drop_modules(
7368   sqlite3 *db,                /* Remove modules from this connection */
7369   const char **azKeep         /* Except, do not remove the ones named here */
7370 );
7371 
7372 /*
7373 ** CAPI3REF: Virtual Table Instance Object
7374 ** KEYWORDS: sqlite3_vtab
7375 **
7376 ** Every [virtual table module] implementation uses a subclass
7377 ** of this object to describe a particular instance
7378 ** of the [virtual table].  Each subclass will
7379 ** be tailored to the specific needs of the module implementation.
7380 ** The purpose of this superclass is to define certain fields that are
7381 ** common to all module implementations.
7382 **
7383 ** ^Virtual tables methods can set an error message by assigning a
7384 ** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
7385 ** take care that any prior string is freed by a call to [sqlite3_free()]
7386 ** prior to assigning a new string to zErrMsg.  ^After the error message
7387 ** is delivered up to the client application, the string will be automatically
7388 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
7389 */
7390 struct sqlite3_vtab {
7391   const sqlite3_module *pModule;  /* The module for this virtual table */
7392   int nRef;                       /* Number of open cursors */
7393   char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
7394   /* Virtual table implementations will typically add additional fields */
7395 };
7396 
7397 /*
7398 ** CAPI3REF: Virtual Table Cursor Object
7399 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
7400 **
7401 ** Every [virtual table module] implementation uses a subclass of the
7402 ** following structure to describe cursors that point into the
7403 ** [virtual table] and are used
7404 ** to loop through the virtual table.  Cursors are created using the
7405 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
7406 ** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
7407 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
7408 ** of the module.  Each module implementation will define
7409 ** the content of a cursor structure to suit its own needs.
7410 **
7411 ** This superclass exists in order to define fields of the cursor that
7412 ** are common to all implementations.
7413 */
7414 struct sqlite3_vtab_cursor {
7415   sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
7416   /* Virtual table implementations will typically add additional fields */
7417 };
7418 
7419 /*
7420 ** CAPI3REF: Declare The Schema Of A Virtual Table
7421 **
7422 ** ^The [xCreate] and [xConnect] methods of a
7423 ** [virtual table module] call this interface
7424 ** to declare the format (the names and datatypes of the columns) of
7425 ** the virtual tables they implement.
7426 */
7427 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
7428 
7429 /*
7430 ** CAPI3REF: Overload A Function For A Virtual Table
7431 ** METHOD: sqlite3
7432 **
7433 ** ^(Virtual tables can provide alternative implementations of functions
7434 ** using the [xFindFunction] method of the [virtual table module].
7435 ** But global versions of those functions
7436 ** must exist in order to be overloaded.)^
7437 **
7438 ** ^(This API makes sure a global version of a function with a particular
7439 ** name and number of parameters exists.  If no such function exists
7440 ** before this API is called, a new function is created.)^  ^The implementation
7441 ** of the new function always causes an exception to be thrown.  So
7442 ** the new function is not good for anything by itself.  Its only
7443 ** purpose is to be a placeholder function that can be overloaded
7444 ** by a [virtual table].
7445 */
7446 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
7447 
7448 /*
7449 ** CAPI3REF: A Handle To An Open BLOB
7450 ** KEYWORDS: {BLOB handle} {BLOB handles}
7451 **
7452 ** An instance of this object represents an open BLOB on which
7453 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
7454 ** ^Objects of this type are created by [sqlite3_blob_open()]
7455 ** and destroyed by [sqlite3_blob_close()].
7456 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
7457 ** can be used to read or write small subsections of the BLOB.
7458 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
7459 */
7460 typedef struct sqlite3_blob sqlite3_blob;
7461 
7462 /*
7463 ** CAPI3REF: Open A BLOB For Incremental I/O
7464 ** METHOD: sqlite3
7465 ** CONSTRUCTOR: sqlite3_blob
7466 **
7467 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
7468 ** in row iRow, column zColumn, table zTable in database zDb;
7469 ** in other words, the same BLOB that would be selected by:
7470 **
7471 ** <pre>
7472 **     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
7473 ** </pre>)^
7474 **
7475 ** ^(Parameter zDb is not the filename that contains the database, but
7476 ** rather the symbolic name of the database. For attached databases, this is
7477 ** the name that appears after the AS keyword in the [ATTACH] statement.
7478 ** For the main database file, the database name is "main". For TEMP
7479 ** tables, the database name is "temp".)^
7480 **
7481 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
7482 ** and write access. ^If the flags parameter is zero, the BLOB is opened for
7483 ** read-only access.
7484 **
7485 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
7486 ** in *ppBlob. Otherwise an [error code] is returned and, unless the error
7487 ** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
7488 ** the API is not misused, it is always safe to call [sqlite3_blob_close()]
7489 ** on *ppBlob after this function it returns.
7490 **
7491 ** This function fails with SQLITE_ERROR if any of the following are true:
7492 ** <ul>
7493 **   <li> ^(Database zDb does not exist)^,
7494 **   <li> ^(Table zTable does not exist within database zDb)^,
7495 **   <li> ^(Table zTable is a WITHOUT ROWID table)^,
7496 **   <li> ^(Column zColumn does not exist)^,
7497 **   <li> ^(Row iRow is not present in the table)^,
7498 **   <li> ^(The specified column of row iRow contains a value that is not
7499 **         a TEXT or BLOB value)^,
7500 **   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
7501 **         constraint and the blob is being opened for read/write access)^,
7502 **   <li> ^([foreign key constraints | Foreign key constraints] are enabled,
7503 **         column zColumn is part of a [child key] definition and the blob is
7504 **         being opened for read/write access)^.
7505 ** </ul>
7506 **
7507 ** ^Unless it returns SQLITE_MISUSE, this function sets the
7508 ** [database connection] error code and message accessible via
7509 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
7510 **
7511 ** A BLOB referenced by sqlite3_blob_open() may be read using the
7512 ** [sqlite3_blob_read()] interface and modified by using
7513 ** [sqlite3_blob_write()].  The [BLOB handle] can be moved to a
7514 ** different row of the same table using the [sqlite3_blob_reopen()]
7515 ** interface.  However, the column, table, or database of a [BLOB handle]
7516 ** cannot be changed after the [BLOB handle] is opened.
7517 **
7518 ** ^(If the row that a BLOB handle points to is modified by an
7519 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
7520 ** then the BLOB handle is marked as "expired".
7521 ** This is true if any column of the row is changed, even a column
7522 ** other than the one the BLOB handle is open on.)^
7523 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
7524 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
7525 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
7526 ** rolled back by the expiration of the BLOB.  Such changes will eventually
7527 ** commit if the transaction continues to completion.)^
7528 **
7529 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
7530 ** the opened blob.  ^The size of a blob may not be changed by this
7531 ** interface.  Use the [UPDATE] SQL command to change the size of a
7532 ** blob.
7533 **
7534 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
7535 ** and the built-in [zeroblob] SQL function may be used to create a
7536 ** zero-filled blob to read or write using the incremental-blob interface.
7537 **
7538 ** To avoid a resource leak, every open [BLOB handle] should eventually
7539 ** be released by a call to [sqlite3_blob_close()].
7540 **
7541 ** See also: [sqlite3_blob_close()],
7542 ** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
7543 ** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
7544 */
7545 SQLITE_API int sqlite3_blob_open(
7546   sqlite3*,
7547   const char *zDb,
7548   const char *zTable,
7549   const char *zColumn,
7550   sqlite3_int64 iRow,
7551   int flags,
7552   sqlite3_blob **ppBlob
7553 );
7554 
7555 /*
7556 ** CAPI3REF: Move a BLOB Handle to a New Row
7557 ** METHOD: sqlite3_blob
7558 **
7559 ** ^This function is used to move an existing [BLOB handle] so that it points
7560 ** to a different row of the same database table. ^The new row is identified
7561 ** by the rowid value passed as the second argument. Only the row can be
7562 ** changed. ^The database, table and column on which the blob handle is open
7563 ** remain the same. Moving an existing [BLOB handle] to a new row is
7564 ** faster than closing the existing handle and opening a new one.
7565 **
7566 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
7567 ** it must exist and there must be either a blob or text value stored in
7568 ** the nominated column.)^ ^If the new row is not present in the table, or if
7569 ** it does not contain a blob or text value, or if another error occurs, an
7570 ** SQLite error code is returned and the blob handle is considered aborted.
7571 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
7572 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
7573 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
7574 ** always returns zero.
7575 **
7576 ** ^This function sets the database handle error code and message.
7577 */
7578 SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
7579 
7580 /*
7581 ** CAPI3REF: Close A BLOB Handle
7582 ** DESTRUCTOR: sqlite3_blob
7583 **
7584 ** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
7585 ** unconditionally.  Even if this routine returns an error code, the
7586 ** handle is still closed.)^
7587 **
7588 ** ^If the blob handle being closed was opened for read-write access, and if
7589 ** the database is in auto-commit mode and there are no other open read-write
7590 ** blob handles or active write statements, the current transaction is
7591 ** committed. ^If an error occurs while committing the transaction, an error
7592 ** code is returned and the transaction rolled back.
7593 **
7594 ** Calling this function with an argument that is not a NULL pointer or an
7595 ** open blob handle results in undefined behaviour. ^Calling this routine
7596 ** with a null pointer (such as would be returned by a failed call to
7597 ** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
7598 ** is passed a valid open blob handle, the values returned by the
7599 ** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
7600 */
7601 SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
7602 
7603 /*
7604 ** CAPI3REF: Return The Size Of An Open BLOB
7605 ** METHOD: sqlite3_blob
7606 **
7607 ** ^Returns the size in bytes of the BLOB accessible via the
7608 ** successfully opened [BLOB handle] in its only argument.  ^The
7609 ** incremental blob I/O routines can only read or overwriting existing
7610 ** blob content; they cannot change the size of a blob.
7611 **
7612 ** This routine only works on a [BLOB handle] which has been created
7613 ** by a prior successful call to [sqlite3_blob_open()] and which has not
7614 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
7615 ** to this routine results in undefined and probably undesirable behavior.
7616 */
7617 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
7618 
7619 /*
7620 ** CAPI3REF: Read Data From A BLOB Incrementally
7621 ** METHOD: sqlite3_blob
7622 **
7623 ** ^(This function is used to read data from an open [BLOB handle] into a
7624 ** caller-supplied buffer. N bytes of data are copied into buffer Z
7625 ** from the open BLOB, starting at offset iOffset.)^
7626 **
7627 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
7628 ** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
7629 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
7630 ** ^The size of the blob (and hence the maximum value of N+iOffset)
7631 ** can be determined using the [sqlite3_blob_bytes()] interface.
7632 **
7633 ** ^An attempt to read from an expired [BLOB handle] fails with an
7634 ** error code of [SQLITE_ABORT].
7635 **
7636 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
7637 ** Otherwise, an [error code] or an [extended error code] is returned.)^
7638 **
7639 ** This routine only works on a [BLOB handle] which has been created
7640 ** by a prior successful call to [sqlite3_blob_open()] and which has not
7641 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
7642 ** to this routine results in undefined and probably undesirable behavior.
7643 **
7644 ** See also: [sqlite3_blob_write()].
7645 */
7646 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
7647 
7648 /*
7649 ** CAPI3REF: Write Data Into A BLOB Incrementally
7650 ** METHOD: sqlite3_blob
7651 **
7652 ** ^(This function is used to write data into an open [BLOB handle] from a
7653 ** caller-supplied buffer. N bytes of data are copied from the buffer Z
7654 ** into the open BLOB, starting at offset iOffset.)^
7655 **
7656 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
7657 ** Otherwise, an  [error code] or an [extended error code] is returned.)^
7658 ** ^Unless SQLITE_MISUSE is returned, this function sets the
7659 ** [database connection] error code and message accessible via
7660 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
7661 **
7662 ** ^If the [BLOB handle] passed as the first argument was not opened for
7663 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
7664 ** this function returns [SQLITE_READONLY].
7665 **
7666 ** This function may only modify the contents of the BLOB; it is
7667 ** not possible to increase the size of a BLOB using this API.
7668 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
7669 ** [SQLITE_ERROR] is returned and no data is written. The size of the
7670 ** BLOB (and hence the maximum value of N+iOffset) can be determined
7671 ** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
7672 ** than zero [SQLITE_ERROR] is returned and no data is written.
7673 **
7674 ** ^An attempt to write to an expired [BLOB handle] fails with an
7675 ** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
7676 ** before the [BLOB handle] expired are not rolled back by the
7677 ** expiration of the handle, though of course those changes might
7678 ** have been overwritten by the statement that expired the BLOB handle
7679 ** or by other independent statements.
7680 **
7681 ** This routine only works on a [BLOB handle] which has been created
7682 ** by a prior successful call to [sqlite3_blob_open()] and which has not
7683 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
7684 ** to this routine results in undefined and probably undesirable behavior.
7685 **
7686 ** See also: [sqlite3_blob_read()].
7687 */
7688 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
7689 
7690 /*
7691 ** CAPI3REF: Virtual File System Objects
7692 **
7693 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
7694 ** that SQLite uses to interact
7695 ** with the underlying operating system.  Most SQLite builds come with a
7696 ** single default VFS that is appropriate for the host computer.
7697 ** New VFSes can be registered and existing VFSes can be unregistered.
7698 ** The following interfaces are provided.
7699 **
7700 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
7701 ** ^Names are case sensitive.
7702 ** ^Names are zero-terminated UTF-8 strings.
7703 ** ^If there is no match, a NULL pointer is returned.
7704 ** ^If zVfsName is NULL then the default VFS is returned.
7705 **
7706 ** ^New VFSes are registered with sqlite3_vfs_register().
7707 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
7708 ** ^The same VFS can be registered multiple times without injury.
7709 ** ^To make an existing VFS into the default VFS, register it again
7710 ** with the makeDflt flag set.  If two different VFSes with the
7711 ** same name are registered, the behavior is undefined.  If a
7712 ** VFS is registered with a name that is NULL or an empty string,
7713 ** then the behavior is undefined.
7714 **
7715 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
7716 ** ^(If the default VFS is unregistered, another VFS is chosen as
7717 ** the default.  The choice for the new VFS is arbitrary.)^
7718 */
7719 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
7720 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
7721 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
7722 
7723 /*
7724 ** CAPI3REF: Mutexes
7725 **
7726 ** The SQLite core uses these routines for thread
7727 ** synchronization. Though they are intended for internal
7728 ** use by SQLite, code that links against SQLite is
7729 ** permitted to use any of these routines.
7730 **
7731 ** The SQLite source code contains multiple implementations
7732 ** of these mutex routines.  An appropriate implementation
7733 ** is selected automatically at compile-time.  The following
7734 ** implementations are available in the SQLite core:
7735 **
7736 ** <ul>
7737 ** <li>   SQLITE_MUTEX_PTHREADS
7738 ** <li>   SQLITE_MUTEX_W32
7739 ** <li>   SQLITE_MUTEX_NOOP
7740 ** </ul>
7741 **
7742 ** The SQLITE_MUTEX_NOOP implementation is a set of routines
7743 ** that does no real locking and is appropriate for use in
7744 ** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
7745 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
7746 ** and Windows.
7747 **
7748 ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
7749 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
7750 ** implementation is included with the library. In this case the
7751 ** application must supply a custom mutex implementation using the
7752 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
7753 ** before calling sqlite3_initialize() or any other public sqlite3_
7754 ** function that calls sqlite3_initialize().
7755 **
7756 ** ^The sqlite3_mutex_alloc() routine allocates a new
7757 ** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
7758 ** routine returns NULL if it is unable to allocate the requested
7759 ** mutex.  The argument to sqlite3_mutex_alloc() must one of these
7760 ** integer constants:
7761 **
7762 ** <ul>
7763 ** <li>  SQLITE_MUTEX_FAST
7764 ** <li>  SQLITE_MUTEX_RECURSIVE
7765 ** <li>  SQLITE_MUTEX_STATIC_MAIN
7766 ** <li>  SQLITE_MUTEX_STATIC_MEM
7767 ** <li>  SQLITE_MUTEX_STATIC_OPEN
7768 ** <li>  SQLITE_MUTEX_STATIC_PRNG
7769 ** <li>  SQLITE_MUTEX_STATIC_LRU
7770 ** <li>  SQLITE_MUTEX_STATIC_PMEM
7771 ** <li>  SQLITE_MUTEX_STATIC_APP1
7772 ** <li>  SQLITE_MUTEX_STATIC_APP2
7773 ** <li>  SQLITE_MUTEX_STATIC_APP3
7774 ** <li>  SQLITE_MUTEX_STATIC_VFS1
7775 ** <li>  SQLITE_MUTEX_STATIC_VFS2
7776 ** <li>  SQLITE_MUTEX_STATIC_VFS3
7777 ** </ul>
7778 **
7779 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
7780 ** cause sqlite3_mutex_alloc() to create
7781 ** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
7782 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
7783 ** The mutex implementation does not need to make a distinction
7784 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
7785 ** not want to.  SQLite will only request a recursive mutex in
7786 ** cases where it really needs one.  If a faster non-recursive mutex
7787 ** implementation is available on the host platform, the mutex subsystem
7788 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
7789 **
7790 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
7791 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
7792 ** a pointer to a static preexisting mutex.  ^Nine static mutexes are
7793 ** used by the current version of SQLite.  Future versions of SQLite
7794 ** may add additional static mutexes.  Static mutexes are for internal
7795 ** use by SQLite only.  Applications that use SQLite mutexes should
7796 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
7797 ** SQLITE_MUTEX_RECURSIVE.
7798 **
7799 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
7800 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
7801 ** returns a different mutex on every call.  ^For the static
7802 ** mutex types, the same mutex is returned on every call that has
7803 ** the same type number.
7804 **
7805 ** ^The sqlite3_mutex_free() routine deallocates a previously
7806 ** allocated dynamic mutex.  Attempting to deallocate a static
7807 ** mutex results in undefined behavior.
7808 **
7809 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
7810 ** to enter a mutex.  ^If another thread is already within the mutex,
7811 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
7812 ** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
7813 ** upon successful entry.  ^(Mutexes created using
7814 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
7815 ** In such cases, the
7816 ** mutex must be exited an equal number of times before another thread
7817 ** can enter.)^  If the same thread tries to enter any mutex other
7818 ** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
7819 **
7820 ** ^(Some systems (for example, Windows 95) do not support the operation
7821 ** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
7822 ** will always return SQLITE_BUSY. The SQLite core only ever uses
7823 ** sqlite3_mutex_try() as an optimization so this is acceptable
7824 ** behavior.)^
7825 **
7826 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
7827 ** previously entered by the same thread.   The behavior
7828 ** is undefined if the mutex is not currently entered by the
7829 ** calling thread or is not currently allocated.
7830 **
7831 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
7832 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
7833 ** behave as no-ops.
7834 **
7835 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
7836 */
7837 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
7838 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
7839 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
7840 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
7841 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
7842 
7843 /*
7844 ** CAPI3REF: Mutex Methods Object
7845 **
7846 ** An instance of this structure defines the low-level routines
7847 ** used to allocate and use mutexes.
7848 **
7849 ** Usually, the default mutex implementations provided by SQLite are
7850 ** sufficient, however the application has the option of substituting a custom
7851 ** implementation for specialized deployments or systems for which SQLite
7852 ** does not provide a suitable implementation. In this case, the application
7853 ** creates and populates an instance of this structure to pass
7854 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
7855 ** Additionally, an instance of this structure can be used as an
7856 ** output variable when querying the system for the current mutex
7857 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
7858 **
7859 ** ^The xMutexInit method defined by this structure is invoked as
7860 ** part of system initialization by the sqlite3_initialize() function.
7861 ** ^The xMutexInit routine is called by SQLite exactly once for each
7862 ** effective call to [sqlite3_initialize()].
7863 **
7864 ** ^The xMutexEnd method defined by this structure is invoked as
7865 ** part of system shutdown by the sqlite3_shutdown() function. The
7866 ** implementation of this method is expected to release all outstanding
7867 ** resources obtained by the mutex methods implementation, especially
7868 ** those obtained by the xMutexInit method.  ^The xMutexEnd()
7869 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
7870 **
7871 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
7872 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
7873 ** xMutexNotheld) implement the following interfaces (respectively):
7874 **
7875 ** <ul>
7876 **   <li>  [sqlite3_mutex_alloc()] </li>
7877 **   <li>  [sqlite3_mutex_free()] </li>
7878 **   <li>  [sqlite3_mutex_enter()] </li>
7879 **   <li>  [sqlite3_mutex_try()] </li>
7880 **   <li>  [sqlite3_mutex_leave()] </li>
7881 **   <li>  [sqlite3_mutex_held()] </li>
7882 **   <li>  [sqlite3_mutex_notheld()] </li>
7883 ** </ul>)^
7884 **
7885 ** The only difference is that the public sqlite3_XXX functions enumerated
7886 ** above silently ignore any invocations that pass a NULL pointer instead
7887 ** of a valid mutex handle. The implementations of the methods defined
7888 ** by this structure are not required to handle this case. The results
7889 ** of passing a NULL pointer instead of a valid mutex handle are undefined
7890 ** (i.e. it is acceptable to provide an implementation that segfaults if
7891 ** it is passed a NULL pointer).
7892 **
7893 ** The xMutexInit() method must be threadsafe.  It must be harmless to
7894 ** invoke xMutexInit() multiple times within the same process and without
7895 ** intervening calls to xMutexEnd().  Second and subsequent calls to
7896 ** xMutexInit() must be no-ops.
7897 **
7898 ** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
7899 ** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
7900 ** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
7901 ** memory allocation for a fast or recursive mutex.
7902 **
7903 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
7904 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
7905 ** If xMutexInit fails in any way, it is expected to clean up after itself
7906 ** prior to returning.
7907 */
7908 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
7909 struct sqlite3_mutex_methods {
7910   int (*xMutexInit)(void);
7911   int (*xMutexEnd)(void);
7912   sqlite3_mutex *(*xMutexAlloc)(int);
7913   void (*xMutexFree)(sqlite3_mutex *);
7914   void (*xMutexEnter)(sqlite3_mutex *);
7915   int (*xMutexTry)(sqlite3_mutex *);
7916   void (*xMutexLeave)(sqlite3_mutex *);
7917   int (*xMutexHeld)(sqlite3_mutex *);
7918   int (*xMutexNotheld)(sqlite3_mutex *);
7919 };
7920 
7921 /*
7922 ** CAPI3REF: Mutex Verification Routines
7923 **
7924 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
7925 ** are intended for use inside assert() statements.  The SQLite core
7926 ** never uses these routines except inside an assert() and applications
7927 ** are advised to follow the lead of the core.  The SQLite core only
7928 ** provides implementations for these routines when it is compiled
7929 ** with the SQLITE_DEBUG flag.  External mutex implementations
7930 ** are only required to provide these routines if SQLITE_DEBUG is
7931 ** defined and if NDEBUG is not defined.
7932 **
7933 ** These routines should return true if the mutex in their argument
7934 ** is held or not held, respectively, by the calling thread.
7935 **
7936 ** The implementation is not required to provide versions of these
7937 ** routines that actually work. If the implementation does not provide working
7938 ** versions of these routines, it should at least provide stubs that always
7939 ** return true so that one does not get spurious assertion failures.
7940 **
7941 ** If the argument to sqlite3_mutex_held() is a NULL pointer then
7942 ** the routine should return 1.   This seems counter-intuitive since
7943 ** clearly the mutex cannot be held if it does not exist.  But
7944 ** the reason the mutex does not exist is because the build is not
7945 ** using mutexes.  And we do not want the assert() containing the
7946 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
7947 ** the appropriate thing to do.  The sqlite3_mutex_notheld()
7948 ** interface should also return 1 when given a NULL pointer.
7949 */
7950 #ifndef NDEBUG
7951 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
7952 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
7953 #endif
7954 
7955 /*
7956 ** CAPI3REF: Mutex Types
7957 **
7958 ** The [sqlite3_mutex_alloc()] interface takes a single argument
7959 ** which is one of these integer constants.
7960 **
7961 ** The set of static mutexes may change from one SQLite release to the
7962 ** next.  Applications that override the built-in mutex logic must be
7963 ** prepared to accommodate additional static mutexes.
7964 */
7965 #define SQLITE_MUTEX_FAST             0
7966 #define SQLITE_MUTEX_RECURSIVE        1
7967 #define SQLITE_MUTEX_STATIC_MAIN      2
7968 #define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
7969 #define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
7970 #define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
7971 #define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_randomness() */
7972 #define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
7973 #define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
7974 #define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
7975 #define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
7976 #define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
7977 #define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
7978 #define SQLITE_MUTEX_STATIC_VFS1     11  /* For use by built-in VFS */
7979 #define SQLITE_MUTEX_STATIC_VFS2     12  /* For use by extension VFS */
7980 #define SQLITE_MUTEX_STATIC_VFS3     13  /* For use by application VFS */
7981 
7982 /* Legacy compatibility: */
7983 #define SQLITE_MUTEX_STATIC_MASTER    2
7984 
7985 
7986 /*
7987 ** CAPI3REF: Retrieve the mutex for a database connection
7988 ** METHOD: sqlite3
7989 **
7990 ** ^This interface returns a pointer the [sqlite3_mutex] object that
7991 ** serializes access to the [database connection] given in the argument
7992 ** when the [threading mode] is Serialized.
7993 ** ^If the [threading mode] is Single-thread or Multi-thread then this
7994 ** routine returns a NULL pointer.
7995 */
7996 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
7997 
7998 /*
7999 ** CAPI3REF: Low-Level Control Of Database Files
8000 ** METHOD: sqlite3
8001 ** KEYWORDS: {file control}
8002 **
8003 ** ^The [sqlite3_file_control()] interface makes a direct call to the
8004 ** xFileControl method for the [sqlite3_io_methods] object associated
8005 ** with a particular database identified by the second argument. ^The
8006 ** name of the database is "main" for the main database or "temp" for the
8007 ** TEMP database, or the name that appears after the AS keyword for
8008 ** databases that are added using the [ATTACH] SQL command.
8009 ** ^A NULL pointer can be used in place of "main" to refer to the
8010 ** main database file.
8011 ** ^The third and fourth parameters to this routine
8012 ** are passed directly through to the second and third parameters of
8013 ** the xFileControl method.  ^The return value of the xFileControl
8014 ** method becomes the return value of this routine.
8015 **
8016 ** A few opcodes for [sqlite3_file_control()] are handled directly
8017 ** by the SQLite core and never invoke the
8018 ** sqlite3_io_methods.xFileControl method.
8019 ** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
8020 ** a pointer to the underlying [sqlite3_file] object to be written into
8021 ** the space pointed to by the 4th parameter.  The
8022 ** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns
8023 ** the [sqlite3_file] object associated with the journal file instead of
8024 ** the main database.  The [SQLITE_FCNTL_VFS_POINTER] opcode returns
8025 ** a pointer to the underlying [sqlite3_vfs] object for the file.
8026 ** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter
8027 ** from the pager.
8028 **
8029 ** ^If the second parameter (zDbName) does not match the name of any
8030 ** open database file, then SQLITE_ERROR is returned.  ^This error
8031 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
8032 ** or [sqlite3_errmsg()].  The underlying xFileControl method might
8033 ** also return SQLITE_ERROR.  There is no way to distinguish between
8034 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
8035 ** xFileControl method.
8036 **
8037 ** See also: [file control opcodes]
8038 */
8039 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
8040 
8041 /*
8042 ** CAPI3REF: Testing Interface
8043 **
8044 ** ^The sqlite3_test_control() interface is used to read out internal
8045 ** state of SQLite and to inject faults into SQLite for testing
8046 ** purposes.  ^The first parameter is an operation code that determines
8047 ** the number, meaning, and operation of all subsequent parameters.
8048 **
8049 ** This interface is not for use by applications.  It exists solely
8050 ** for verifying the correct operation of the SQLite library.  Depending
8051 ** on how the SQLite library is compiled, this interface might not exist.
8052 **
8053 ** The details of the operation codes, their meanings, the parameters
8054 ** they take, and what they do are all subject to change without notice.
8055 ** Unlike most of the SQLite API, this function is not guaranteed to
8056 ** operate consistently from one release to the next.
8057 */
8058 SQLITE_API int sqlite3_test_control(int op, ...);
8059 
8060 /*
8061 ** CAPI3REF: Testing Interface Operation Codes
8062 **
8063 ** These constants are the valid operation code parameters used
8064 ** as the first argument to [sqlite3_test_control()].
8065 **
8066 ** These parameters and their meanings are subject to change
8067 ** without notice.  These values are for testing purposes only.
8068 ** Applications should not use any of these parameters or the
8069 ** [sqlite3_test_control()] interface.
8070 */
8071 #define SQLITE_TESTCTRL_FIRST                    5
8072 #define SQLITE_TESTCTRL_PRNG_SAVE                5
8073 #define SQLITE_TESTCTRL_PRNG_RESTORE             6
8074 #define SQLITE_TESTCTRL_PRNG_RESET               7  /* NOT USED */
8075 #define SQLITE_TESTCTRL_BITVEC_TEST              8
8076 #define SQLITE_TESTCTRL_FAULT_INSTALL            9
8077 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
8078 #define SQLITE_TESTCTRL_PENDING_BYTE            11
8079 #define SQLITE_TESTCTRL_ASSERT                  12
8080 #define SQLITE_TESTCTRL_ALWAYS                  13
8081 #define SQLITE_TESTCTRL_RESERVE                 14  /* NOT USED */
8082 #define SQLITE_TESTCTRL_OPTIMIZATIONS           15
8083 #define SQLITE_TESTCTRL_ISKEYWORD               16  /* NOT USED */
8084 #define SQLITE_TESTCTRL_SCRATCHMALLOC           17  /* NOT USED */
8085 #define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS      17
8086 #define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
8087 #define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
8088 #define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD    19
8089 #define SQLITE_TESTCTRL_NEVER_CORRUPT           20
8090 #define SQLITE_TESTCTRL_VDBE_COVERAGE           21
8091 #define SQLITE_TESTCTRL_BYTEORDER               22
8092 #define SQLITE_TESTCTRL_ISINIT                  23
8093 #define SQLITE_TESTCTRL_SORTER_MMAP             24
8094 #define SQLITE_TESTCTRL_IMPOSTER                25
8095 #define SQLITE_TESTCTRL_PARSER_COVERAGE         26
8096 #define SQLITE_TESTCTRL_RESULT_INTREAL          27
8097 #define SQLITE_TESTCTRL_PRNG_SEED               28
8098 #define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS     29
8099 #define SQLITE_TESTCTRL_SEEK_COUNT              30
8100 #define SQLITE_TESTCTRL_TRACEFLAGS              31
8101 #define SQLITE_TESTCTRL_TUNE                    32
8102 #define SQLITE_TESTCTRL_LOGEST                  33
8103 #define SQLITE_TESTCTRL_LAST                    33  /* Largest TESTCTRL */
8104 
8105 /*
8106 ** CAPI3REF: SQL Keyword Checking
8107 **
8108 ** These routines provide access to the set of SQL language keywords
8109 ** recognized by SQLite.  Applications can uses these routines to determine
8110 ** whether or not a specific identifier needs to be escaped (for example,
8111 ** by enclosing in double-quotes) so as not to confuse the parser.
8112 **
8113 ** The sqlite3_keyword_count() interface returns the number of distinct
8114 ** keywords understood by SQLite.
8115 **
8116 ** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and
8117 ** makes *Z point to that keyword expressed as UTF8 and writes the number
8118 ** of bytes in the keyword into *L.  The string that *Z points to is not
8119 ** zero-terminated.  The sqlite3_keyword_name(N,Z,L) routine returns
8120 ** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
8121 ** or L are NULL or invalid pointers then calls to
8122 ** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
8123 **
8124 ** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
8125 ** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
8126 ** if it is and zero if not.
8127 **
8128 ** The parser used by SQLite is forgiving.  It is often possible to use
8129 ** a keyword as an identifier as long as such use does not result in a
8130 ** parsing ambiguity.  For example, the statement
8131 ** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
8132 ** creates a new table named "BEGIN" with three columns named
8133 ** "REPLACE", "PRAGMA", and "END".  Nevertheless, best practice is to avoid
8134 ** using keywords as identifiers.  Common techniques used to avoid keyword
8135 ** name collisions include:
8136 ** <ul>
8137 ** <li> Put all identifier names inside double-quotes.  This is the official
8138 **      SQL way to escape identifier names.
8139 ** <li> Put identifier names inside &#91;...&#93;.  This is not standard SQL,
8140 **      but it is what SQL Server does and so lots of programmers use this
8141 **      technique.
8142 ** <li> Begin every identifier with the letter "Z" as no SQL keywords start
8143 **      with "Z".
8144 ** <li> Include a digit somewhere in every identifier name.
8145 ** </ul>
8146 **
8147 ** Note that the number of keywords understood by SQLite can depend on
8148 ** compile-time options.  For example, "VACUUM" is not a keyword if
8149 ** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option.  Also,
8150 ** new keywords may be added to future releases of SQLite.
8151 */
8152 SQLITE_API int sqlite3_keyword_count(void);
8153 SQLITE_API int sqlite3_keyword_name(int,const char**,int*);
8154 SQLITE_API int sqlite3_keyword_check(const char*,int);
8155 
8156 /*
8157 ** CAPI3REF: Dynamic String Object
8158 ** KEYWORDS: {dynamic string}
8159 **
8160 ** An instance of the sqlite3_str object contains a dynamically-sized
8161 ** string under construction.
8162 **
8163 ** The lifecycle of an sqlite3_str object is as follows:
8164 ** <ol>
8165 ** <li> ^The sqlite3_str object is created using [sqlite3_str_new()].
8166 ** <li> ^Text is appended to the sqlite3_str object using various
8167 ** methods, such as [sqlite3_str_appendf()].
8168 ** <li> ^The sqlite3_str object is destroyed and the string it created
8169 ** is returned using the [sqlite3_str_finish()] interface.
8170 ** </ol>
8171 */
8172 typedef struct sqlite3_str sqlite3_str;
8173 
8174 /*
8175 ** CAPI3REF: Create A New Dynamic String Object
8176 ** CONSTRUCTOR: sqlite3_str
8177 **
8178 ** ^The [sqlite3_str_new(D)] interface allocates and initializes
8179 ** a new [sqlite3_str] object.  To avoid memory leaks, the object returned by
8180 ** [sqlite3_str_new()] must be freed by a subsequent call to
8181 ** [sqlite3_str_finish(X)].
8182 **
8183 ** ^The [sqlite3_str_new(D)] interface always returns a pointer to a
8184 ** valid [sqlite3_str] object, though in the event of an out-of-memory
8185 ** error the returned object might be a special singleton that will
8186 ** silently reject new text, always return SQLITE_NOMEM from
8187 ** [sqlite3_str_errcode()], always return 0 for
8188 ** [sqlite3_str_length()], and always return NULL from
8189 ** [sqlite3_str_finish(X)].  It is always safe to use the value
8190 ** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter
8191 ** to any of the other [sqlite3_str] methods.
8192 **
8193 ** The D parameter to [sqlite3_str_new(D)] may be NULL.  If the
8194 ** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum
8195 ** length of the string contained in the [sqlite3_str] object will be
8196 ** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead
8197 ** of [SQLITE_MAX_LENGTH].
8198 */
8199 SQLITE_API sqlite3_str *sqlite3_str_new(sqlite3*);
8200 
8201 /*
8202 ** CAPI3REF: Finalize A Dynamic String
8203 ** DESTRUCTOR: sqlite3_str
8204 **
8205 ** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
8206 ** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
8207 ** that contains the constructed string.  The calling application should
8208 ** pass the returned value to [sqlite3_free()] to avoid a memory leak.
8209 ** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
8210 ** errors were encountered during construction of the string.  ^The
8211 ** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the
8212 ** string in [sqlite3_str] object X is zero bytes long.
8213 */
8214 SQLITE_API char *sqlite3_str_finish(sqlite3_str*);
8215 
8216 /*
8217 ** CAPI3REF: Add Content To A Dynamic String
8218 ** METHOD: sqlite3_str
8219 **
8220 ** These interfaces add content to an sqlite3_str object previously obtained
8221 ** from [sqlite3_str_new()].
8222 **
8223 ** ^The [sqlite3_str_appendf(X,F,...)] and
8224 ** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
8225 ** functionality of SQLite to append formatted text onto the end of
8226 ** [sqlite3_str] object X.
8227 **
8228 ** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
8229 ** onto the end of the [sqlite3_str] object X.  N must be non-negative.
8230 ** S must contain at least N non-zero bytes of content.  To append a
8231 ** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
8232 ** method instead.
8233 **
8234 ** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of
8235 ** zero-terminated string S onto the end of [sqlite3_str] object X.
8236 **
8237 ** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
8238 ** single-byte character C onto the end of [sqlite3_str] object X.
8239 ** ^This method can be used, for example, to add whitespace indentation.
8240 **
8241 ** ^The [sqlite3_str_reset(X)] method resets the string under construction
8242 ** inside [sqlite3_str] object X back to zero bytes in length.
8243 **
8244 ** These methods do not return a result code.  ^If an error occurs, that fact
8245 ** is recorded in the [sqlite3_str] object and can be recovered by a
8246 ** subsequent call to [sqlite3_str_errcode(X)].
8247 */
8248 SQLITE_API void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
8249 SQLITE_API void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
8250 SQLITE_API void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
8251 SQLITE_API void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
8252 SQLITE_API void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
8253 SQLITE_API void sqlite3_str_reset(sqlite3_str*);
8254 
8255 /*
8256 ** CAPI3REF: Status Of A Dynamic String
8257 ** METHOD: sqlite3_str
8258 **
8259 ** These interfaces return the current status of an [sqlite3_str] object.
8260 **
8261 ** ^If any prior errors have occurred while constructing the dynamic string
8262 ** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
8263 ** an appropriate error code.  ^The [sqlite3_str_errcode(X)] method returns
8264 ** [SQLITE_NOMEM] following any out-of-memory error, or
8265 ** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
8266 ** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
8267 **
8268 ** ^The [sqlite3_str_length(X)] method returns the current length, in bytes,
8269 ** of the dynamic string under construction in [sqlite3_str] object X.
8270 ** ^The length returned by [sqlite3_str_length(X)] does not include the
8271 ** zero-termination byte.
8272 **
8273 ** ^The [sqlite3_str_value(X)] method returns a pointer to the current
8274 ** content of the dynamic string under construction in X.  The value
8275 ** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
8276 ** and might be freed or altered by any subsequent method on the same
8277 ** [sqlite3_str] object.  Applications must not used the pointer returned
8278 ** [sqlite3_str_value(X)] after any subsequent method call on the same
8279 ** object.  ^Applications may change the content of the string returned
8280 ** by [sqlite3_str_value(X)] as long as they do not write into any bytes
8281 ** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
8282 ** write any byte after any subsequent sqlite3_str method call.
8283 */
8284 SQLITE_API int sqlite3_str_errcode(sqlite3_str*);
8285 SQLITE_API int sqlite3_str_length(sqlite3_str*);
8286 SQLITE_API char *sqlite3_str_value(sqlite3_str*);
8287 
8288 /*
8289 ** CAPI3REF: SQLite Runtime Status
8290 **
8291 ** ^These interfaces are used to retrieve runtime status information
8292 ** about the performance of SQLite, and optionally to reset various
8293 ** highwater marks.  ^The first argument is an integer code for
8294 ** the specific parameter to measure.  ^(Recognized integer codes
8295 ** are of the form [status parameters | SQLITE_STATUS_...].)^
8296 ** ^The current value of the parameter is returned into *pCurrent.
8297 ** ^The highest recorded value is returned in *pHighwater.  ^If the
8298 ** resetFlag is true, then the highest record value is reset after
8299 ** *pHighwater is written.  ^(Some parameters do not record the highest
8300 ** value.  For those parameters
8301 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
8302 ** ^(Other parameters record only the highwater mark and not the current
8303 ** value.  For these latter parameters nothing is written into *pCurrent.)^
8304 **
8305 ** ^The sqlite3_status() and sqlite3_status64() routines return
8306 ** SQLITE_OK on success and a non-zero [error code] on failure.
8307 **
8308 ** If either the current value or the highwater mark is too large to
8309 ** be represented by a 32-bit integer, then the values returned by
8310 ** sqlite3_status() are undefined.
8311 **
8312 ** See also: [sqlite3_db_status()]
8313 */
8314 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
8315 SQLITE_API int sqlite3_status64(
8316   int op,
8317   sqlite3_int64 *pCurrent,
8318   sqlite3_int64 *pHighwater,
8319   int resetFlag
8320 );
8321 
8322 
8323 /*
8324 ** CAPI3REF: Status Parameters
8325 ** KEYWORDS: {status parameters}
8326 **
8327 ** These integer constants designate various run-time status parameters
8328 ** that can be returned by [sqlite3_status()].
8329 **
8330 ** <dl>
8331 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
8332 ** <dd>This parameter is the current amount of memory checked out
8333 ** using [sqlite3_malloc()], either directly or indirectly.  The
8334 ** figure includes calls made to [sqlite3_malloc()] by the application
8335 ** and internal memory usage by the SQLite library.  Auxiliary page-cache
8336 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
8337 ** this parameter.  The amount returned is the sum of the allocation
8338 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
8339 **
8340 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
8341 ** <dd>This parameter records the largest memory allocation request
8342 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
8343 ** internal equivalents).  Only the value returned in the
8344 ** *pHighwater parameter to [sqlite3_status()] is of interest.
8345 ** The value written into the *pCurrent parameter is undefined.</dd>)^
8346 **
8347 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
8348 ** <dd>This parameter records the number of separate memory allocations
8349 ** currently checked out.</dd>)^
8350 **
8351 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
8352 ** <dd>This parameter returns the number of pages used out of the
8353 ** [pagecache memory allocator] that was configured using
8354 ** [SQLITE_CONFIG_PAGECACHE].  The
8355 ** value returned is in pages, not in bytes.</dd>)^
8356 **
8357 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
8358 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
8359 ** <dd>This parameter returns the number of bytes of page cache
8360 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
8361 ** buffer and where forced to overflow to [sqlite3_malloc()].  The
8362 ** returned value includes allocations that overflowed because they
8363 ** where too large (they were larger than the "sz" parameter to
8364 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
8365 ** no space was left in the page cache.</dd>)^
8366 **
8367 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
8368 ** <dd>This parameter records the largest memory allocation request
8369 ** handed to the [pagecache memory allocator].  Only the value returned in the
8370 ** *pHighwater parameter to [sqlite3_status()] is of interest.
8371 ** The value written into the *pCurrent parameter is undefined.</dd>)^
8372 **
8373 ** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
8374 ** <dd>No longer used.</dd>
8375 **
8376 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
8377 ** <dd>No longer used.</dd>
8378 **
8379 ** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
8380 ** <dd>No longer used.</dd>
8381 **
8382 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
8383 ** <dd>The *pHighwater parameter records the deepest parser stack.
8384 ** The *pCurrent value is undefined.  The *pHighwater value is only
8385 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
8386 ** </dl>
8387 **
8388 ** New status parameters may be added from time to time.
8389 */
8390 #define SQLITE_STATUS_MEMORY_USED          0
8391 #define SQLITE_STATUS_PAGECACHE_USED       1
8392 #define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
8393 #define SQLITE_STATUS_SCRATCH_USED         3  /* NOT USED */
8394 #define SQLITE_STATUS_SCRATCH_OVERFLOW     4  /* NOT USED */
8395 #define SQLITE_STATUS_MALLOC_SIZE          5
8396 #define SQLITE_STATUS_PARSER_STACK         6
8397 #define SQLITE_STATUS_PAGECACHE_SIZE       7
8398 #define SQLITE_STATUS_SCRATCH_SIZE         8  /* NOT USED */
8399 #define SQLITE_STATUS_MALLOC_COUNT         9
8400 
8401 /*
8402 ** CAPI3REF: Database Connection Status
8403 ** METHOD: sqlite3
8404 **
8405 ** ^This interface is used to retrieve runtime status information
8406 ** about a single [database connection].  ^The first argument is the
8407 ** database connection object to be interrogated.  ^The second argument
8408 ** is an integer constant, taken from the set of
8409 ** [SQLITE_DBSTATUS options], that
8410 ** determines the parameter to interrogate.  The set of
8411 ** [SQLITE_DBSTATUS options] is likely
8412 ** to grow in future releases of SQLite.
8413 **
8414 ** ^The current value of the requested parameter is written into *pCur
8415 ** and the highest instantaneous value is written into *pHiwtr.  ^If
8416 ** the resetFlg is true, then the highest instantaneous value is
8417 ** reset back down to the current value.
8418 **
8419 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
8420 ** non-zero [error code] on failure.
8421 **
8422 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
8423 */
8424 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
8425 
8426 /*
8427 ** CAPI3REF: Status Parameters for database connections
8428 ** KEYWORDS: {SQLITE_DBSTATUS options}
8429 **
8430 ** These constants are the available integer "verbs" that can be passed as
8431 ** the second argument to the [sqlite3_db_status()] interface.
8432 **
8433 ** New verbs may be added in future releases of SQLite. Existing verbs
8434 ** might be discontinued. Applications should check the return code from
8435 ** [sqlite3_db_status()] to make sure that the call worked.
8436 ** The [sqlite3_db_status()] interface will return a non-zero error code
8437 ** if a discontinued or unsupported verb is invoked.
8438 **
8439 ** <dl>
8440 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
8441 ** <dd>This parameter returns the number of lookaside memory slots currently
8442 ** checked out.</dd>)^
8443 **
8444 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
8445 ** <dd>This parameter returns the number of malloc attempts that were
8446 ** satisfied using lookaside memory. Only the high-water value is meaningful;
8447 ** the current value is always zero.)^
8448 **
8449 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
8450 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
8451 ** <dd>This parameter returns the number malloc attempts that might have
8452 ** been satisfied using lookaside memory but failed due to the amount of
8453 ** memory requested being larger than the lookaside slot size.
8454 ** Only the high-water value is meaningful;
8455 ** the current value is always zero.)^
8456 **
8457 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
8458 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
8459 ** <dd>This parameter returns the number malloc attempts that might have
8460 ** been satisfied using lookaside memory but failed due to all lookaside
8461 ** memory already being in use.
8462 ** Only the high-water value is meaningful;
8463 ** the current value is always zero.)^
8464 **
8465 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
8466 ** <dd>This parameter returns the approximate number of bytes of heap
8467 ** memory used by all pager caches associated with the database connection.)^
8468 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
8469 **
8470 ** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
8471 ** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
8472 ** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
8473 ** pager cache is shared between two or more connections the bytes of heap
8474 ** memory used by that pager cache is divided evenly between the attached
8475 ** connections.)^  In other words, if none of the pager caches associated
8476 ** with the database connection are shared, this request returns the same
8477 ** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
8478 ** shared, the value returned by this call will be smaller than that returned
8479 ** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
8480 ** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
8481 **
8482 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
8483 ** <dd>This parameter returns the approximate number of bytes of heap
8484 ** memory used to store the schema for all databases associated
8485 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
8486 ** ^The full amount of memory used by the schemas is reported, even if the
8487 ** schema memory is shared with other database connections due to
8488 ** [shared cache mode] being enabled.
8489 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
8490 **
8491 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
8492 ** <dd>This parameter returns the approximate number of bytes of heap
8493 ** and lookaside memory used by all prepared statements associated with
8494 ** the database connection.)^
8495 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
8496 ** </dd>
8497 **
8498 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
8499 ** <dd>This parameter returns the number of pager cache hits that have
8500 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
8501 ** is always 0.
8502 ** </dd>
8503 **
8504 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
8505 ** <dd>This parameter returns the number of pager cache misses that have
8506 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
8507 ** is always 0.
8508 ** </dd>
8509 **
8510 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
8511 ** <dd>This parameter returns the number of dirty cache entries that have
8512 ** been written to disk. Specifically, the number of pages written to the
8513 ** wal file in wal mode databases, or the number of pages written to the
8514 ** database file in rollback mode databases. Any pages written as part of
8515 ** transaction rollback or database recovery operations are not included.
8516 ** If an IO or other error occurs while writing a page to disk, the effect
8517 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
8518 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
8519 ** </dd>
8520 **
8521 ** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
8522 ** <dd>This parameter returns the number of dirty cache entries that have
8523 ** been written to disk in the middle of a transaction due to the page
8524 ** cache overflowing. Transactions are more efficient if they are written
8525 ** to disk all at once. When pages spill mid-transaction, that introduces
8526 ** additional overhead. This parameter can be used help identify
8527 ** inefficiencies that can be resolved by increasing the cache size.
8528 ** </dd>
8529 **
8530 ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
8531 ** <dd>This parameter returns zero for the current value if and only if
8532 ** all foreign key constraints (deferred or immediate) have been
8533 ** resolved.)^  ^The highwater mark is always 0.
8534 ** </dd>
8535 ** </dl>
8536 */
8537 #define SQLITE_DBSTATUS_LOOKASIDE_USED       0
8538 #define SQLITE_DBSTATUS_CACHE_USED           1
8539 #define SQLITE_DBSTATUS_SCHEMA_USED          2
8540 #define SQLITE_DBSTATUS_STMT_USED            3
8541 #define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
8542 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
8543 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
8544 #define SQLITE_DBSTATUS_CACHE_HIT            7
8545 #define SQLITE_DBSTATUS_CACHE_MISS           8
8546 #define SQLITE_DBSTATUS_CACHE_WRITE          9
8547 #define SQLITE_DBSTATUS_DEFERRED_FKS        10
8548 #define SQLITE_DBSTATUS_CACHE_USED_SHARED   11
8549 #define SQLITE_DBSTATUS_CACHE_SPILL         12
8550 #define SQLITE_DBSTATUS_MAX                 12   /* Largest defined DBSTATUS */
8551 
8552 
8553 /*
8554 ** CAPI3REF: Prepared Statement Status
8555 ** METHOD: sqlite3_stmt
8556 **
8557 ** ^(Each prepared statement maintains various
8558 ** [SQLITE_STMTSTATUS counters] that measure the number
8559 ** of times it has performed specific operations.)^  These counters can
8560 ** be used to monitor the performance characteristics of the prepared
8561 ** statements.  For example, if the number of table steps greatly exceeds
8562 ** the number of table searches or result rows, that would tend to indicate
8563 ** that the prepared statement is using a full table scan rather than
8564 ** an index.
8565 **
8566 ** ^(This interface is used to retrieve and reset counter values from
8567 ** a [prepared statement].  The first argument is the prepared statement
8568 ** object to be interrogated.  The second argument
8569 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
8570 ** to be interrogated.)^
8571 ** ^The current value of the requested counter is returned.
8572 ** ^If the resetFlg is true, then the counter is reset to zero after this
8573 ** interface call returns.
8574 **
8575 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
8576 */
8577 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
8578 
8579 /*
8580 ** CAPI3REF: Status Parameters for prepared statements
8581 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
8582 **
8583 ** These preprocessor macros define integer codes that name counter
8584 ** values associated with the [sqlite3_stmt_status()] interface.
8585 ** The meanings of the various counters are as follows:
8586 **
8587 ** <dl>
8588 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
8589 ** <dd>^This is the number of times that SQLite has stepped forward in
8590 ** a table as part of a full table scan.  Large numbers for this counter
8591 ** may indicate opportunities for performance improvement through
8592 ** careful use of indices.</dd>
8593 **
8594 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
8595 ** <dd>^This is the number of sort operations that have occurred.
8596 ** A non-zero value in this counter may indicate an opportunity to
8597 ** improvement performance through careful use of indices.</dd>
8598 **
8599 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
8600 ** <dd>^This is the number of rows inserted into transient indices that
8601 ** were created automatically in order to help joins run faster.
8602 ** A non-zero value in this counter may indicate an opportunity to
8603 ** improvement performance by adding permanent indices that do not
8604 ** need to be reinitialized each time the statement is run.</dd>
8605 **
8606 ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
8607 ** <dd>^This is the number of virtual machine operations executed
8608 ** by the prepared statement if that number is less than or equal
8609 ** to 2147483647.  The number of virtual machine operations can be
8610 ** used as a proxy for the total work done by the prepared statement.
8611 ** If the number of virtual machine operations exceeds 2147483647
8612 ** then the value returned by this statement status code is undefined.
8613 **
8614 ** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
8615 ** <dd>^This is the number of times that the prepare statement has been
8616 ** automatically regenerated due to schema changes or changes to
8617 ** [bound parameters] that might affect the query plan.
8618 **
8619 ** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
8620 ** <dd>^This is the number of times that the prepared statement has
8621 ** been run.  A single "run" for the purposes of this counter is one
8622 ** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
8623 ** The counter is incremented on the first [sqlite3_step()] call of each
8624 ** cycle.
8625 **
8626 ** [[SQLITE_STMTSTATUS_FILTER_MISS]]
8627 ** [[SQLITE_STMTSTATUS_FILTER HIT]]
8628 ** <dt>SQLITE_STMTSTATUS_FILTER_HIT<br>
8629 ** SQLITE_STMTSTATUS_FILTER_MISS</dt>
8630 ** <dd>^SQLITE_STMTSTATUS_FILTER_HIT is the number of times that a join
8631 ** step was bypassed because a Bloom filter returned not-found.  The
8632 ** corresponding SQLITE_STMTSTATUS_FILTER_MISS value is the number of
8633 ** times that the Bloom filter returned a find, and thus the join step
8634 ** had to be processed as normal.
8635 **
8636 ** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
8637 ** <dd>^This is the approximate number of bytes of heap memory
8638 ** used to store the prepared statement.  ^This value is not actually
8639 ** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
8640 ** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
8641 ** </dd>
8642 ** </dl>
8643 */
8644 #define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
8645 #define SQLITE_STMTSTATUS_SORT              2
8646 #define SQLITE_STMTSTATUS_AUTOINDEX         3
8647 #define SQLITE_STMTSTATUS_VM_STEP           4
8648 #define SQLITE_STMTSTATUS_REPREPARE         5
8649 #define SQLITE_STMTSTATUS_RUN               6
8650 #define SQLITE_STMTSTATUS_FILTER_MISS       7
8651 #define SQLITE_STMTSTATUS_FILTER_HIT        8
8652 #define SQLITE_STMTSTATUS_MEMUSED           99
8653 
8654 /*
8655 ** CAPI3REF: Custom Page Cache Object
8656 **
8657 ** The sqlite3_pcache type is opaque.  It is implemented by
8658 ** the pluggable module.  The SQLite core has no knowledge of
8659 ** its size or internal structure and never deals with the
8660 ** sqlite3_pcache object except by holding and passing pointers
8661 ** to the object.
8662 **
8663 ** See [sqlite3_pcache_methods2] for additional information.
8664 */
8665 typedef struct sqlite3_pcache sqlite3_pcache;
8666 
8667 /*
8668 ** CAPI3REF: Custom Page Cache Object
8669 **
8670 ** The sqlite3_pcache_page object represents a single page in the
8671 ** page cache.  The page cache will allocate instances of this
8672 ** object.  Various methods of the page cache use pointers to instances
8673 ** of this object as parameters or as their return value.
8674 **
8675 ** See [sqlite3_pcache_methods2] for additional information.
8676 */
8677 typedef struct sqlite3_pcache_page sqlite3_pcache_page;
8678 struct sqlite3_pcache_page {
8679   void *pBuf;        /* The content of the page */
8680   void *pExtra;      /* Extra information associated with the page */
8681 };
8682 
8683 /*
8684 ** CAPI3REF: Application Defined Page Cache.
8685 ** KEYWORDS: {page cache}
8686 **
8687 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
8688 ** register an alternative page cache implementation by passing in an
8689 ** instance of the sqlite3_pcache_methods2 structure.)^
8690 ** In many applications, most of the heap memory allocated by
8691 ** SQLite is used for the page cache.
8692 ** By implementing a
8693 ** custom page cache using this API, an application can better control
8694 ** the amount of memory consumed by SQLite, the way in which
8695 ** that memory is allocated and released, and the policies used to
8696 ** determine exactly which parts of a database file are cached and for
8697 ** how long.
8698 **
8699 ** The alternative page cache mechanism is an
8700 ** extreme measure that is only needed by the most demanding applications.
8701 ** The built-in page cache is recommended for most uses.
8702 **
8703 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
8704 ** internal buffer by SQLite within the call to [sqlite3_config].  Hence
8705 ** the application may discard the parameter after the call to
8706 ** [sqlite3_config()] returns.)^
8707 **
8708 ** [[the xInit() page cache method]]
8709 ** ^(The xInit() method is called once for each effective
8710 ** call to [sqlite3_initialize()])^
8711 ** (usually only once during the lifetime of the process). ^(The xInit()
8712 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
8713 ** The intent of the xInit() method is to set up global data structures
8714 ** required by the custom page cache implementation.
8715 ** ^(If the xInit() method is NULL, then the
8716 ** built-in default page cache is used instead of the application defined
8717 ** page cache.)^
8718 **
8719 ** [[the xShutdown() page cache method]]
8720 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
8721 ** It can be used to clean up
8722 ** any outstanding resources before process shutdown, if required.
8723 ** ^The xShutdown() method may be NULL.
8724 **
8725 ** ^SQLite automatically serializes calls to the xInit method,
8726 ** so the xInit method need not be threadsafe.  ^The
8727 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
8728 ** not need to be threadsafe either.  All other methods must be threadsafe
8729 ** in multithreaded applications.
8730 **
8731 ** ^SQLite will never invoke xInit() more than once without an intervening
8732 ** call to xShutdown().
8733 **
8734 ** [[the xCreate() page cache methods]]
8735 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
8736 ** SQLite will typically create one cache instance for each open database file,
8737 ** though this is not guaranteed. ^The
8738 ** first parameter, szPage, is the size in bytes of the pages that must
8739 ** be allocated by the cache.  ^szPage will always a power of two.  ^The
8740 ** second parameter szExtra is a number of bytes of extra storage
8741 ** associated with each page cache entry.  ^The szExtra parameter will
8742 ** a number less than 250.  SQLite will use the
8743 ** extra szExtra bytes on each page to store metadata about the underlying
8744 ** database page on disk.  The value passed into szExtra depends
8745 ** on the SQLite version, the target platform, and how SQLite was compiled.
8746 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
8747 ** created will be used to cache database pages of a file stored on disk, or
8748 ** false if it is used for an in-memory database. The cache implementation
8749 ** does not have to do anything special based with the value of bPurgeable;
8750 ** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
8751 ** never invoke xUnpin() except to deliberately delete a page.
8752 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
8753 ** false will always have the "discard" flag set to true.
8754 ** ^Hence, a cache created with bPurgeable false will
8755 ** never contain any unpinned pages.
8756 **
8757 ** [[the xCachesize() page cache method]]
8758 ** ^(The xCachesize() method may be called at any time by SQLite to set the
8759 ** suggested maximum cache-size (number of pages stored by) the cache
8760 ** instance passed as the first argument. This is the value configured using
8761 ** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
8762 ** parameter, the implementation is not required to do anything with this
8763 ** value; it is advisory only.
8764 **
8765 ** [[the xPagecount() page cache methods]]
8766 ** The xPagecount() method must return the number of pages currently
8767 ** stored in the cache, both pinned and unpinned.
8768 **
8769 ** [[the xFetch() page cache methods]]
8770 ** The xFetch() method locates a page in the cache and returns a pointer to
8771 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
8772 ** The pBuf element of the returned sqlite3_pcache_page object will be a
8773 ** pointer to a buffer of szPage bytes used to store the content of a
8774 ** single database page.  The pExtra element of sqlite3_pcache_page will be
8775 ** a pointer to the szExtra bytes of extra storage that SQLite has requested
8776 ** for each entry in the page cache.
8777 **
8778 ** The page to be fetched is determined by the key. ^The minimum key value
8779 ** is 1.  After it has been retrieved using xFetch, the page is considered
8780 ** to be "pinned".
8781 **
8782 ** If the requested page is already in the page cache, then the page cache
8783 ** implementation must return a pointer to the page buffer with its content
8784 ** intact.  If the requested page is not already in the cache, then the
8785 ** cache implementation should use the value of the createFlag
8786 ** parameter to help it determined what action to take:
8787 **
8788 ** <table border=1 width=85% align=center>
8789 ** <tr><th> createFlag <th> Behavior when page is not already in cache
8790 ** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
8791 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
8792 **                 Otherwise return NULL.
8793 ** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
8794 **                 NULL if allocating a new page is effectively impossible.
8795 ** </table>
8796 **
8797 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
8798 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
8799 ** failed.)^  In between the xFetch() calls, SQLite may
8800 ** attempt to unpin one or more cache pages by spilling the content of
8801 ** pinned pages to disk and synching the operating system disk cache.
8802 **
8803 ** [[the xUnpin() page cache method]]
8804 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
8805 ** as its second argument.  If the third parameter, discard, is non-zero,
8806 ** then the page must be evicted from the cache.
8807 ** ^If the discard parameter is
8808 ** zero, then the page may be discarded or retained at the discretion of
8809 ** page cache implementation. ^The page cache implementation
8810 ** may choose to evict unpinned pages at any time.
8811 **
8812 ** The cache must not perform any reference counting. A single
8813 ** call to xUnpin() unpins the page regardless of the number of prior calls
8814 ** to xFetch().
8815 **
8816 ** [[the xRekey() page cache methods]]
8817 ** The xRekey() method is used to change the key value associated with the
8818 ** page passed as the second argument. If the cache
8819 ** previously contains an entry associated with newKey, it must be
8820 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
8821 ** to be pinned.
8822 **
8823 ** When SQLite calls the xTruncate() method, the cache must discard all
8824 ** existing cache entries with page numbers (keys) greater than or equal
8825 ** to the value of the iLimit parameter passed to xTruncate(). If any
8826 ** of these pages are pinned, they are implicitly unpinned, meaning that
8827 ** they can be safely discarded.
8828 **
8829 ** [[the xDestroy() page cache method]]
8830 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
8831 ** All resources associated with the specified cache should be freed. ^After
8832 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
8833 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
8834 ** functions.
8835 **
8836 ** [[the xShrink() page cache method]]
8837 ** ^SQLite invokes the xShrink() method when it wants the page cache to
8838 ** free up as much of heap memory as possible.  The page cache implementation
8839 ** is not obligated to free any memory, but well-behaved implementations should
8840 ** do their best.
8841 */
8842 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
8843 struct sqlite3_pcache_methods2 {
8844   int iVersion;
8845   void *pArg;
8846   int (*xInit)(void*);
8847   void (*xShutdown)(void*);
8848   sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
8849   void (*xCachesize)(sqlite3_pcache*, int nCachesize);
8850   int (*xPagecount)(sqlite3_pcache*);
8851   sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
8852   void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
8853   void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
8854       unsigned oldKey, unsigned newKey);
8855   void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
8856   void (*xDestroy)(sqlite3_pcache*);
8857   void (*xShrink)(sqlite3_pcache*);
8858 };
8859 
8860 /*
8861 ** This is the obsolete pcache_methods object that has now been replaced
8862 ** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
8863 ** retained in the header file for backwards compatibility only.
8864 */
8865 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
8866 struct sqlite3_pcache_methods {
8867   void *pArg;
8868   int (*xInit)(void*);
8869   void (*xShutdown)(void*);
8870   sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
8871   void (*xCachesize)(sqlite3_pcache*, int nCachesize);
8872   int (*xPagecount)(sqlite3_pcache*);
8873   void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
8874   void (*xUnpin)(sqlite3_pcache*, void*, int discard);
8875   void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
8876   void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
8877   void (*xDestroy)(sqlite3_pcache*);
8878 };
8879 
8880 
8881 /*
8882 ** CAPI3REF: Online Backup Object
8883 **
8884 ** The sqlite3_backup object records state information about an ongoing
8885 ** online backup operation.  ^The sqlite3_backup object is created by
8886 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
8887 ** [sqlite3_backup_finish()].
8888 **
8889 ** See Also: [Using the SQLite Online Backup API]
8890 */
8891 typedef struct sqlite3_backup sqlite3_backup;
8892 
8893 /*
8894 ** CAPI3REF: Online Backup API.
8895 **
8896 ** The backup API copies the content of one database into another.
8897 ** It is useful either for creating backups of databases or
8898 ** for copying in-memory databases to or from persistent files.
8899 **
8900 ** See Also: [Using the SQLite Online Backup API]
8901 **
8902 ** ^SQLite holds a write transaction open on the destination database file
8903 ** for the duration of the backup operation.
8904 ** ^The source database is read-locked only while it is being read;
8905 ** it is not locked continuously for the entire backup operation.
8906 ** ^Thus, the backup may be performed on a live source database without
8907 ** preventing other database connections from
8908 ** reading or writing to the source database while the backup is underway.
8909 **
8910 ** ^(To perform a backup operation:
8911 **   <ol>
8912 **     <li><b>sqlite3_backup_init()</b> is called once to initialize the
8913 **         backup,
8914 **     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
8915 **         the data between the two databases, and finally
8916 **     <li><b>sqlite3_backup_finish()</b> is called to release all resources
8917 **         associated with the backup operation.
8918 **   </ol>)^
8919 ** There should be exactly one call to sqlite3_backup_finish() for each
8920 ** successful call to sqlite3_backup_init().
8921 **
8922 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
8923 **
8924 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
8925 ** [database connection] associated with the destination database
8926 ** and the database name, respectively.
8927 ** ^The database name is "main" for the main database, "temp" for the
8928 ** temporary database, or the name specified after the AS keyword in
8929 ** an [ATTACH] statement for an attached database.
8930 ** ^The S and M arguments passed to
8931 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
8932 ** and database name of the source database, respectively.
8933 ** ^The source and destination [database connections] (parameters S and D)
8934 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
8935 ** an error.
8936 **
8937 ** ^A call to sqlite3_backup_init() will fail, returning NULL, if
8938 ** there is already a read or read-write transaction open on the
8939 ** destination database.
8940 **
8941 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
8942 ** returned and an error code and error message are stored in the
8943 ** destination [database connection] D.
8944 ** ^The error code and message for the failed call to sqlite3_backup_init()
8945 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
8946 ** [sqlite3_errmsg16()] functions.
8947 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
8948 ** [sqlite3_backup] object.
8949 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
8950 ** sqlite3_backup_finish() functions to perform the specified backup
8951 ** operation.
8952 **
8953 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
8954 **
8955 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
8956 ** the source and destination databases specified by [sqlite3_backup] object B.
8957 ** ^If N is negative, all remaining source pages are copied.
8958 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
8959 ** are still more pages to be copied, then the function returns [SQLITE_OK].
8960 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
8961 ** from source to destination, then it returns [SQLITE_DONE].
8962 ** ^If an error occurs while running sqlite3_backup_step(B,N),
8963 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
8964 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
8965 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
8966 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
8967 **
8968 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
8969 ** <ol>
8970 ** <li> the destination database was opened read-only, or
8971 ** <li> the destination database is using write-ahead-log journaling
8972 ** and the destination and source page sizes differ, or
8973 ** <li> the destination database is an in-memory database and the
8974 ** destination and source page sizes differ.
8975 ** </ol>)^
8976 **
8977 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
8978 ** the [sqlite3_busy_handler | busy-handler function]
8979 ** is invoked (if one is specified). ^If the
8980 ** busy-handler returns non-zero before the lock is available, then
8981 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
8982 ** sqlite3_backup_step() can be retried later. ^If the source
8983 ** [database connection]
8984 ** is being used to write to the source database when sqlite3_backup_step()
8985 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
8986 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
8987 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
8988 ** [SQLITE_READONLY] is returned, then
8989 ** there is no point in retrying the call to sqlite3_backup_step(). These
8990 ** errors are considered fatal.)^  The application must accept
8991 ** that the backup operation has failed and pass the backup operation handle
8992 ** to the sqlite3_backup_finish() to release associated resources.
8993 **
8994 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
8995 ** on the destination file. ^The exclusive lock is not released until either
8996 ** sqlite3_backup_finish() is called or the backup operation is complete
8997 ** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
8998 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
8999 ** lasts for the duration of the sqlite3_backup_step() call.
9000 ** ^Because the source database is not locked between calls to
9001 ** sqlite3_backup_step(), the source database may be modified mid-way
9002 ** through the backup process.  ^If the source database is modified by an
9003 ** external process or via a database connection other than the one being
9004 ** used by the backup operation, then the backup will be automatically
9005 ** restarted by the next call to sqlite3_backup_step(). ^If the source
9006 ** database is modified by the using the same database connection as is used
9007 ** by the backup operation, then the backup database is automatically
9008 ** updated at the same time.
9009 **
9010 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
9011 **
9012 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
9013 ** application wishes to abandon the backup operation, the application
9014 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
9015 ** ^The sqlite3_backup_finish() interfaces releases all
9016 ** resources associated with the [sqlite3_backup] object.
9017 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
9018 ** active write-transaction on the destination database is rolled back.
9019 ** The [sqlite3_backup] object is invalid
9020 ** and may not be used following a call to sqlite3_backup_finish().
9021 **
9022 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
9023 ** sqlite3_backup_step() errors occurred, regardless or whether or not
9024 ** sqlite3_backup_step() completed.
9025 ** ^If an out-of-memory condition or IO error occurred during any prior
9026 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
9027 ** sqlite3_backup_finish() returns the corresponding [error code].
9028 **
9029 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
9030 ** is not a permanent error and does not affect the return value of
9031 ** sqlite3_backup_finish().
9032 **
9033 ** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
9034 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
9035 **
9036 ** ^The sqlite3_backup_remaining() routine returns the number of pages still
9037 ** to be backed up at the conclusion of the most recent sqlite3_backup_step().
9038 ** ^The sqlite3_backup_pagecount() routine returns the total number of pages
9039 ** in the source database at the conclusion of the most recent
9040 ** sqlite3_backup_step().
9041 ** ^(The values returned by these functions are only updated by
9042 ** sqlite3_backup_step(). If the source database is modified in a way that
9043 ** changes the size of the source database or the number of pages remaining,
9044 ** those changes are not reflected in the output of sqlite3_backup_pagecount()
9045 ** and sqlite3_backup_remaining() until after the next
9046 ** sqlite3_backup_step().)^
9047 **
9048 ** <b>Concurrent Usage of Database Handles</b>
9049 **
9050 ** ^The source [database connection] may be used by the application for other
9051 ** purposes while a backup operation is underway or being initialized.
9052 ** ^If SQLite is compiled and configured to support threadsafe database
9053 ** connections, then the source database connection may be used concurrently
9054 ** from within other threads.
9055 **
9056 ** However, the application must guarantee that the destination
9057 ** [database connection] is not passed to any other API (by any thread) after
9058 ** sqlite3_backup_init() is called and before the corresponding call to
9059 ** sqlite3_backup_finish().  SQLite does not currently check to see
9060 ** if the application incorrectly accesses the destination [database connection]
9061 ** and so no error code is reported, but the operations may malfunction
9062 ** nevertheless.  Use of the destination database connection while a
9063 ** backup is in progress might also cause a mutex deadlock.
9064 **
9065 ** If running in [shared cache mode], the application must
9066 ** guarantee that the shared cache used by the destination database
9067 ** is not accessed while the backup is running. In practice this means
9068 ** that the application must guarantee that the disk file being
9069 ** backed up to is not accessed by any connection within the process,
9070 ** not just the specific connection that was passed to sqlite3_backup_init().
9071 **
9072 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
9073 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
9074 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
9075 ** APIs are not strictly speaking threadsafe. If they are invoked at the
9076 ** same time as another thread is invoking sqlite3_backup_step() it is
9077 ** possible that they return invalid values.
9078 */
9079 SQLITE_API sqlite3_backup *sqlite3_backup_init(
9080   sqlite3 *pDest,                        /* Destination database handle */
9081   const char *zDestName,                 /* Destination database name */
9082   sqlite3 *pSource,                      /* Source database handle */
9083   const char *zSourceName                /* Source database name */
9084 );
9085 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
9086 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
9087 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
9088 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
9089 
9090 /*
9091 ** CAPI3REF: Unlock Notification
9092 ** METHOD: sqlite3
9093 **
9094 ** ^When running in shared-cache mode, a database operation may fail with
9095 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
9096 ** individual tables within the shared-cache cannot be obtained. See
9097 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
9098 ** ^This API may be used to register a callback that SQLite will invoke
9099 ** when the connection currently holding the required lock relinquishes it.
9100 ** ^This API is only available if the library was compiled with the
9101 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
9102 **
9103 ** See Also: [Using the SQLite Unlock Notification Feature].
9104 **
9105 ** ^Shared-cache locks are released when a database connection concludes
9106 ** its current transaction, either by committing it or rolling it back.
9107 **
9108 ** ^When a connection (known as the blocked connection) fails to obtain a
9109 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
9110 ** identity of the database connection (the blocking connection) that
9111 ** has locked the required resource is stored internally. ^After an
9112 ** application receives an SQLITE_LOCKED error, it may call the
9113 ** sqlite3_unlock_notify() method with the blocked connection handle as
9114 ** the first argument to register for a callback that will be invoked
9115 ** when the blocking connections current transaction is concluded. ^The
9116 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
9117 ** call that concludes the blocking connection's transaction.
9118 **
9119 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
9120 ** there is a chance that the blocking connection will have already
9121 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
9122 ** If this happens, then the specified callback is invoked immediately,
9123 ** from within the call to sqlite3_unlock_notify().)^
9124 **
9125 ** ^If the blocked connection is attempting to obtain a write-lock on a
9126 ** shared-cache table, and more than one other connection currently holds
9127 ** a read-lock on the same table, then SQLite arbitrarily selects one of
9128 ** the other connections to use as the blocking connection.
9129 **
9130 ** ^(There may be at most one unlock-notify callback registered by a
9131 ** blocked connection. If sqlite3_unlock_notify() is called when the
9132 ** blocked connection already has a registered unlock-notify callback,
9133 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
9134 ** called with a NULL pointer as its second argument, then any existing
9135 ** unlock-notify callback is canceled. ^The blocked connections
9136 ** unlock-notify callback may also be canceled by closing the blocked
9137 ** connection using [sqlite3_close()].
9138 **
9139 ** The unlock-notify callback is not reentrant. If an application invokes
9140 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
9141 ** crash or deadlock may be the result.
9142 **
9143 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
9144 ** returns SQLITE_OK.
9145 **
9146 ** <b>Callback Invocation Details</b>
9147 **
9148 ** When an unlock-notify callback is registered, the application provides a
9149 ** single void* pointer that is passed to the callback when it is invoked.
9150 ** However, the signature of the callback function allows SQLite to pass
9151 ** it an array of void* context pointers. The first argument passed to
9152 ** an unlock-notify callback is a pointer to an array of void* pointers,
9153 ** and the second is the number of entries in the array.
9154 **
9155 ** When a blocking connection's transaction is concluded, there may be
9156 ** more than one blocked connection that has registered for an unlock-notify
9157 ** callback. ^If two or more such blocked connections have specified the
9158 ** same callback function, then instead of invoking the callback function
9159 ** multiple times, it is invoked once with the set of void* context pointers
9160 ** specified by the blocked connections bundled together into an array.
9161 ** This gives the application an opportunity to prioritize any actions
9162 ** related to the set of unblocked database connections.
9163 **
9164 ** <b>Deadlock Detection</b>
9165 **
9166 ** Assuming that after registering for an unlock-notify callback a
9167 ** database waits for the callback to be issued before taking any further
9168 ** action (a reasonable assumption), then using this API may cause the
9169 ** application to deadlock. For example, if connection X is waiting for
9170 ** connection Y's transaction to be concluded, and similarly connection
9171 ** Y is waiting on connection X's transaction, then neither connection
9172 ** will proceed and the system may remain deadlocked indefinitely.
9173 **
9174 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
9175 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
9176 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
9177 ** unlock-notify callback is registered. The system is said to be in
9178 ** a deadlocked state if connection A has registered for an unlock-notify
9179 ** callback on the conclusion of connection B's transaction, and connection
9180 ** B has itself registered for an unlock-notify callback when connection
9181 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
9182 ** the system is also considered to be deadlocked if connection B has
9183 ** registered for an unlock-notify callback on the conclusion of connection
9184 ** C's transaction, where connection C is waiting on connection A. ^Any
9185 ** number of levels of indirection are allowed.
9186 **
9187 ** <b>The "DROP TABLE" Exception</b>
9188 **
9189 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
9190 ** always appropriate to call sqlite3_unlock_notify(). There is however,
9191 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
9192 ** SQLite checks if there are any currently executing SELECT statements
9193 ** that belong to the same connection. If there are, SQLITE_LOCKED is
9194 ** returned. In this case there is no "blocking connection", so invoking
9195 ** sqlite3_unlock_notify() results in the unlock-notify callback being
9196 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
9197 ** or "DROP INDEX" query, an infinite loop might be the result.
9198 **
9199 ** One way around this problem is to check the extended error code returned
9200 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
9201 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
9202 ** the special "DROP TABLE/INDEX" case, the extended error code is just
9203 ** SQLITE_LOCKED.)^
9204 */
9205 SQLITE_API int sqlite3_unlock_notify(
9206   sqlite3 *pBlocked,                          /* Waiting connection */
9207   void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
9208   void *pNotifyArg                            /* Argument to pass to xNotify */
9209 );
9210 
9211 
9212 /*
9213 ** CAPI3REF: String Comparison
9214 **
9215 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
9216 ** and extensions to compare the contents of two buffers containing UTF-8
9217 ** strings in a case-independent fashion, using the same definition of "case
9218 ** independence" that SQLite uses internally when comparing identifiers.
9219 */
9220 SQLITE_API int sqlite3_stricmp(const char *, const char *);
9221 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
9222 
9223 /*
9224 ** CAPI3REF: String Globbing
9225 *
9226 ** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
9227 ** string X matches the [GLOB] pattern P.
9228 ** ^The definition of [GLOB] pattern matching used in
9229 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
9230 ** SQL dialect understood by SQLite.  ^The [sqlite3_strglob(P,X)] function
9231 ** is case sensitive.
9232 **
9233 ** Note that this routine returns zero on a match and non-zero if the strings
9234 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
9235 **
9236 ** See also: [sqlite3_strlike()].
9237 */
9238 SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
9239 
9240 /*
9241 ** CAPI3REF: String LIKE Matching
9242 *
9243 ** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
9244 ** string X matches the [LIKE] pattern P with escape character E.
9245 ** ^The definition of [LIKE] pattern matching used in
9246 ** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
9247 ** operator in the SQL dialect understood by SQLite.  ^For "X LIKE P" without
9248 ** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
9249 ** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
9250 ** insensitive - equivalent upper and lower case ASCII characters match
9251 ** one another.
9252 **
9253 ** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
9254 ** only ASCII characters are case folded.
9255 **
9256 ** Note that this routine returns zero on a match and non-zero if the strings
9257 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
9258 **
9259 ** See also: [sqlite3_strglob()].
9260 */
9261 SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
9262 
9263 /*
9264 ** CAPI3REF: Error Logging Interface
9265 **
9266 ** ^The [sqlite3_log()] interface writes a message into the [error log]
9267 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
9268 ** ^If logging is enabled, the zFormat string and subsequent arguments are
9269 ** used with [sqlite3_snprintf()] to generate the final output string.
9270 **
9271 ** The sqlite3_log() interface is intended for use by extensions such as
9272 ** virtual tables, collating functions, and SQL functions.  While there is
9273 ** nothing to prevent an application from calling sqlite3_log(), doing so
9274 ** is considered bad form.
9275 **
9276 ** The zFormat string must not be NULL.
9277 **
9278 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
9279 ** will not use dynamically allocated memory.  The log message is stored in
9280 ** a fixed-length buffer on the stack.  If the log message is longer than
9281 ** a few hundred characters, it will be truncated to the length of the
9282 ** buffer.
9283 */
9284 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
9285 
9286 /*
9287 ** CAPI3REF: Write-Ahead Log Commit Hook
9288 ** METHOD: sqlite3
9289 **
9290 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
9291 ** is invoked each time data is committed to a database in wal mode.
9292 **
9293 ** ^(The callback is invoked by SQLite after the commit has taken place and
9294 ** the associated write-lock on the database released)^, so the implementation
9295 ** may read, write or [checkpoint] the database as required.
9296 **
9297 ** ^The first parameter passed to the callback function when it is invoked
9298 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
9299 ** registering the callback. ^The second is a copy of the database handle.
9300 ** ^The third parameter is the name of the database that was written to -
9301 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
9302 ** is the number of pages currently in the write-ahead log file,
9303 ** including those that were just committed.
9304 **
9305 ** The callback function should normally return [SQLITE_OK].  ^If an error
9306 ** code is returned, that error will propagate back up through the
9307 ** SQLite code base to cause the statement that provoked the callback
9308 ** to report an error, though the commit will have still occurred. If the
9309 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
9310 ** that does not correspond to any valid SQLite error code, the results
9311 ** are undefined.
9312 **
9313 ** A single database handle may have at most a single write-ahead log callback
9314 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
9315 ** previously registered write-ahead log callback. ^The return value is
9316 ** a copy of the third parameter from the previous call, if any, or 0.
9317 ** ^Note that the [sqlite3_wal_autocheckpoint()] interface and the
9318 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
9319 ** overwrite any prior [sqlite3_wal_hook()] settings.
9320 */
9321 SQLITE_API void *sqlite3_wal_hook(
9322   sqlite3*,
9323   int(*)(void *,sqlite3*,const char*,int),
9324   void*
9325 );
9326 
9327 /*
9328 ** CAPI3REF: Configure an auto-checkpoint
9329 ** METHOD: sqlite3
9330 **
9331 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
9332 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
9333 ** to automatically [checkpoint]
9334 ** after committing a transaction if there are N or
9335 ** more frames in the [write-ahead log] file.  ^Passing zero or
9336 ** a negative value as the nFrame parameter disables automatic
9337 ** checkpoints entirely.
9338 **
9339 ** ^The callback registered by this function replaces any existing callback
9340 ** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
9341 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
9342 ** configured by this function.
9343 **
9344 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
9345 ** from SQL.
9346 **
9347 ** ^Checkpoints initiated by this mechanism are
9348 ** [sqlite3_wal_checkpoint_v2|PASSIVE].
9349 **
9350 ** ^Every new [database connection] defaults to having the auto-checkpoint
9351 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
9352 ** pages.  The use of this interface
9353 ** is only necessary if the default setting is found to be suboptimal
9354 ** for a particular application.
9355 */
9356 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
9357 
9358 /*
9359 ** CAPI3REF: Checkpoint a database
9360 ** METHOD: sqlite3
9361 **
9362 ** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
9363 ** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
9364 **
9365 ** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
9366 ** [write-ahead log] for database X on [database connection] D to be
9367 ** transferred into the database file and for the write-ahead log to
9368 ** be reset.  See the [checkpointing] documentation for addition
9369 ** information.
9370 **
9371 ** This interface used to be the only way to cause a checkpoint to
9372 ** occur.  But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
9373 ** interface was added.  This interface is retained for backwards
9374 ** compatibility and as a convenience for applications that need to manually
9375 ** start a callback but which do not need the full power (and corresponding
9376 ** complication) of [sqlite3_wal_checkpoint_v2()].
9377 */
9378 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
9379 
9380 /*
9381 ** CAPI3REF: Checkpoint a database
9382 ** METHOD: sqlite3
9383 **
9384 ** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
9385 ** operation on database X of [database connection] D in mode M.  Status
9386 ** information is written back into integers pointed to by L and C.)^
9387 ** ^(The M parameter must be a valid [checkpoint mode]:)^
9388 **
9389 ** <dl>
9390 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
9391 **   ^Checkpoint as many frames as possible without waiting for any database
9392 **   readers or writers to finish, then sync the database file if all frames
9393 **   in the log were checkpointed. ^The [busy-handler callback]
9394 **   is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
9395 **   ^On the other hand, passive mode might leave the checkpoint unfinished
9396 **   if there are concurrent readers or writers.
9397 **
9398 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
9399 **   ^This mode blocks (it invokes the
9400 **   [sqlite3_busy_handler|busy-handler callback]) until there is no
9401 **   database writer and all readers are reading from the most recent database
9402 **   snapshot. ^It then checkpoints all frames in the log file and syncs the
9403 **   database file. ^This mode blocks new database writers while it is pending,
9404 **   but new database readers are allowed to continue unimpeded.
9405 **
9406 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
9407 **   ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
9408 **   that after checkpointing the log file it blocks (calls the
9409 **   [busy-handler callback])
9410 **   until all readers are reading from the database file only. ^This ensures
9411 **   that the next writer will restart the log file from the beginning.
9412 **   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
9413 **   database writer attempts while it is pending, but does not impede readers.
9414 **
9415 ** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
9416 **   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
9417 **   addition that it also truncates the log file to zero bytes just prior
9418 **   to a successful return.
9419 ** </dl>
9420 **
9421 ** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
9422 ** the log file or to -1 if the checkpoint could not run because
9423 ** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
9424 ** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
9425 ** log file (including any that were already checkpointed before the function
9426 ** was called) or to -1 if the checkpoint could not run due to an error or
9427 ** because the database is not in WAL mode. ^Note that upon successful
9428 ** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
9429 ** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
9430 **
9431 ** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
9432 ** any other process is running a checkpoint operation at the same time, the
9433 ** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
9434 ** busy-handler configured, it will not be invoked in this case.
9435 **
9436 ** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
9437 ** exclusive "writer" lock on the database file. ^If the writer lock cannot be
9438 ** obtained immediately, and a busy-handler is configured, it is invoked and
9439 ** the writer lock retried until either the busy-handler returns 0 or the lock
9440 ** is successfully obtained. ^The busy-handler is also invoked while waiting for
9441 ** database readers as described above. ^If the busy-handler returns 0 before
9442 ** the writer lock is obtained or while waiting for database readers, the
9443 ** checkpoint operation proceeds from that point in the same way as
9444 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
9445 ** without blocking any further. ^SQLITE_BUSY is returned in this case.
9446 **
9447 ** ^If parameter zDb is NULL or points to a zero length string, then the
9448 ** specified operation is attempted on all WAL databases [attached] to
9449 ** [database connection] db.  In this case the
9450 ** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
9451 ** an SQLITE_BUSY error is encountered when processing one or more of the
9452 ** attached WAL databases, the operation is still attempted on any remaining
9453 ** attached databases and SQLITE_BUSY is returned at the end. ^If any other
9454 ** error occurs while processing an attached database, processing is abandoned
9455 ** and the error code is returned to the caller immediately. ^If no error
9456 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
9457 ** databases, SQLITE_OK is returned.
9458 **
9459 ** ^If database zDb is the name of an attached database that is not in WAL
9460 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
9461 ** zDb is not NULL (or a zero length string) and is not the name of any
9462 ** attached database, SQLITE_ERROR is returned to the caller.
9463 **
9464 ** ^Unless it returns SQLITE_MISUSE,
9465 ** the sqlite3_wal_checkpoint_v2() interface
9466 ** sets the error information that is queried by
9467 ** [sqlite3_errcode()] and [sqlite3_errmsg()].
9468 **
9469 ** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
9470 ** from SQL.
9471 */
9472 SQLITE_API int sqlite3_wal_checkpoint_v2(
9473   sqlite3 *db,                    /* Database handle */
9474   const char *zDb,                /* Name of attached database (or NULL) */
9475   int eMode,                      /* SQLITE_CHECKPOINT_* value */
9476   int *pnLog,                     /* OUT: Size of WAL log in frames */
9477   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
9478 );
9479 
9480 /*
9481 ** CAPI3REF: Checkpoint Mode Values
9482 ** KEYWORDS: {checkpoint mode}
9483 **
9484 ** These constants define all valid values for the "checkpoint mode" passed
9485 ** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
9486 ** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
9487 ** meaning of each of these checkpoint modes.
9488 */
9489 #define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
9490 #define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
9491 #define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for readers */
9492 #define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */
9493 
9494 /*
9495 ** CAPI3REF: Virtual Table Interface Configuration
9496 **
9497 ** This function may be called by either the [xConnect] or [xCreate] method
9498 ** of a [virtual table] implementation to configure
9499 ** various facets of the virtual table interface.
9500 **
9501 ** If this interface is invoked outside the context of an xConnect or
9502 ** xCreate virtual table method then the behavior is undefined.
9503 **
9504 ** In the call sqlite3_vtab_config(D,C,...) the D parameter is the
9505 ** [database connection] in which the virtual table is being created and
9506 ** which is passed in as the first argument to the [xConnect] or [xCreate]
9507 ** method that is invoking sqlite3_vtab_config().  The C parameter is one
9508 ** of the [virtual table configuration options].  The presence and meaning
9509 ** of parameters after C depend on which [virtual table configuration option]
9510 ** is used.
9511 */
9512 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
9513 
9514 /*
9515 ** CAPI3REF: Virtual Table Configuration Options
9516 ** KEYWORDS: {virtual table configuration options}
9517 ** KEYWORDS: {virtual table configuration option}
9518 **
9519 ** These macros define the various options to the
9520 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
9521 ** can use to customize and optimize their behavior.
9522 **
9523 ** <dl>
9524 ** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]]
9525 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt>
9526 ** <dd>Calls of the form
9527 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
9528 ** where X is an integer.  If X is zero, then the [virtual table] whose
9529 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
9530 ** support constraints.  In this configuration (which is the default) if
9531 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
9532 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
9533 ** specified as part of the users SQL statement, regardless of the actual
9534 ** ON CONFLICT mode specified.
9535 **
9536 ** If X is non-zero, then the virtual table implementation guarantees
9537 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
9538 ** any modifications to internal or persistent data structures have been made.
9539 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
9540 ** is able to roll back a statement or database transaction, and abandon
9541 ** or continue processing the current SQL statement as appropriate.
9542 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
9543 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
9544 ** had been ABORT.
9545 **
9546 ** Virtual table implementations that are required to handle OR REPLACE
9547 ** must do so within the [xUpdate] method. If a call to the
9548 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
9549 ** CONFLICT policy is REPLACE, the virtual table implementation should
9550 ** silently replace the appropriate rows within the xUpdate callback and
9551 ** return SQLITE_OK. Or, if this is not possible, it may return
9552 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
9553 ** constraint handling.
9554 ** </dd>
9555 **
9556 ** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt>
9557 ** <dd>Calls of the form
9558 ** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the
9559 ** the [xConnect] or [xCreate] methods of a [virtual table] implmentation
9560 ** prohibits that virtual table from being used from within triggers and
9561 ** views.
9562 ** </dd>
9563 **
9564 ** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt>
9565 ** <dd>Calls of the form
9566 ** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the
9567 ** the [xConnect] or [xCreate] methods of a [virtual table] implmentation
9568 ** identify that virtual table as being safe to use from within triggers
9569 ** and views.  Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the
9570 ** virtual table can do no serious harm even if it is controlled by a
9571 ** malicious hacker.  Developers should avoid setting the SQLITE_VTAB_INNOCUOUS
9572 ** flag unless absolutely necessary.
9573 ** </dd>
9574 ** </dl>
9575 */
9576 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
9577 #define SQLITE_VTAB_INNOCUOUS          2
9578 #define SQLITE_VTAB_DIRECTONLY         3
9579 
9580 /*
9581 ** CAPI3REF: Determine The Virtual Table Conflict Policy
9582 **
9583 ** This function may only be called from within a call to the [xUpdate] method
9584 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
9585 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
9586 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
9587 ** of the SQL statement that triggered the call to the [xUpdate] method of the
9588 ** [virtual table].
9589 */
9590 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
9591 
9592 /*
9593 ** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
9594 **
9595 ** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
9596 ** method of a [virtual table], then it might return true if the
9597 ** column is being fetched as part of an UPDATE operation during which the
9598 ** column value will not change.  The virtual table implementation can use
9599 ** this hint as permission to substitute a return value that is less
9600 ** expensive to compute and that the corresponding
9601 ** [xUpdate] method understands as a "no-change" value.
9602 **
9603 ** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
9604 ** the column is not changed by the UPDATE statement, then the xColumn
9605 ** method can optionally return without setting a result, without calling
9606 ** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
9607 ** In that case, [sqlite3_value_nochange(X)] will return true for the
9608 ** same column in the [xUpdate] method.
9609 **
9610 ** The sqlite3_vtab_nochange() routine is an optimization.  Virtual table
9611 ** implementations should continue to give a correct answer even if the
9612 ** sqlite3_vtab_nochange() interface were to always return false.  In the
9613 ** current implementation, the sqlite3_vtab_nochange() interface does always
9614 ** returns false for the enhanced [UPDATE FROM] statement.
9615 */
9616 SQLITE_API int sqlite3_vtab_nochange(sqlite3_context*);
9617 
9618 /*
9619 ** CAPI3REF: Determine The Collation For a Virtual Table Constraint
9620 ** METHOD: sqlite3_index_info
9621 **
9622 ** This function may only be called from within a call to the [xBestIndex]
9623 ** method of a [virtual table].  This function returns a pointer to a string
9624 ** that is the name of the appropriate collation sequence to use for text
9625 ** comparisons on the constraint identified by its arguments.
9626 **
9627 ** The first argument must be the pointer to the [sqlite3_index_info] object
9628 ** that is the first parameter to the xBestIndex() method. The second argument
9629 ** must be an index into the aConstraint[] array belonging to the
9630 ** sqlite3_index_info structure passed to xBestIndex.
9631 **
9632 ** Important:
9633 ** The first parameter must be the same pointer that is passed into the
9634 ** xBestMethod() method.  The first parameter may not be a pointer to a
9635 ** different [sqlite3_index_info] object, even an exact copy.
9636 **
9637 ** The return value is computed as follows:
9638 **
9639 ** <ol>
9640 ** <li><p> If the constraint comes from a WHERE clause expression that contains
9641 **         a [COLLATE operator], then the name of the collation specified by
9642 **         that COLLATE operator is returned.
9643 ** <li><p> If there is no COLLATE operator, but the column that is the subject
9644 **         of the constraint specifies an alternative collating sequence via
9645 **         a [COLLATE clause] on the column definition within the CREATE TABLE
9646 **         statement that was passed into [sqlite3_declare_vtab()], then the
9647 **         name of that alternative collating sequence is returned.
9648 ** <li><p> Otherwise, "BINARY" is returned.
9649 ** </ol>
9650 */
9651 SQLITE_API const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
9652 
9653 /*
9654 ** CAPI3REF: Determine if a virtual table query is DISTINCT
9655 ** METHOD: sqlite3_index_info
9656 **
9657 ** This API may only be used from within an [xBestIndex|xBestIndex method]
9658 ** of a [virtual table] implementation. The result of calling this
9659 ** interface from outside of xBestIndex() is undefined and probably harmful.
9660 **
9661 ** ^The sqlite3_vtab_distinct() interface returns an integer between 0 and
9662 ** 3.  The integer returned by sqlite3_vtab_distinct()
9663 ** gives the virtual table additional information about how the query
9664 ** planner wants the output to be ordered. As long as the virtual table
9665 ** can meet the ordering requirements of the query planner, it may set
9666 ** the "orderByConsumed" flag.
9667 **
9668 ** <ol><li value="0"><p>
9669 ** ^If the sqlite3_vtab_distinct() interface returns 0, that means
9670 ** that the query planner needs the virtual table to return all rows in the
9671 ** sort order defined by the "nOrderBy" and "aOrderBy" fields of the
9672 ** [sqlite3_index_info] object.  This is the default expectation.  If the
9673 ** virtual table outputs all rows in sorted order, then it is always safe for
9674 ** the xBestIndex method to set the "orderByConsumed" flag, regardless of
9675 ** the return value from sqlite3_vtab_distinct().
9676 ** <li value="1"><p>
9677 ** ^(If the sqlite3_vtab_distinct() interface returns 1, that means
9678 ** that the query planner does not need the rows to be returned in sorted order
9679 ** as long as all rows with the same values in all columns identified by the
9680 ** "aOrderBy" field are adjacent.)^  This mode is used when the query planner
9681 ** is doing a GROUP BY.
9682 ** <li value="2"><p>
9683 ** ^(If the sqlite3_vtab_distinct() interface returns 2, that means
9684 ** that the query planner does not need the rows returned in any particular
9685 ** order, as long as rows with the same values in all "aOrderBy" columns
9686 ** are adjacent.)^  ^(Furthermore, only a single row for each particular
9687 ** combination of values in the columns identified by the "aOrderBy" field
9688 ** needs to be returned.)^  ^It is always ok for two or more rows with the same
9689 ** values in all "aOrderBy" columns to be returned, as long as all such rows
9690 ** are adjacent.  ^The virtual table may, if it chooses, omit extra rows
9691 ** that have the same value for all columns identified by "aOrderBy".
9692 ** ^However omitting the extra rows is optional.
9693 ** This mode is used for a DISTINCT query.
9694 ** <li value="3"><p>
9695 ** ^(If the sqlite3_vtab_distinct() interface returns 3, that means
9696 ** that the query planner needs only distinct rows but it does need the
9697 ** rows to be sorted.)^ ^The virtual table implementation is free to omit
9698 ** rows that are identical in all aOrderBy columns, if it wants to, but
9699 ** it is not required to omit any rows.  This mode is used for queries
9700 ** that have both DISTINCT and ORDER BY clauses.
9701 ** </ol>
9702 **
9703 ** ^For the purposes of comparing virtual table output values to see if the
9704 ** values are same value for sorting purposes, two NULL values are considered
9705 ** to be the same.  In other words, the comparison operator is "IS"
9706 ** (or "IS NOT DISTINCT FROM") and not "==".
9707 **
9708 ** If a virtual table implementation is unable to meet the requirements
9709 ** specified above, then it must not set the "orderByConsumed" flag in the
9710 ** [sqlite3_index_info] object or an incorrect answer may result.
9711 **
9712 ** ^A virtual table implementation is always free to return rows in any order
9713 ** it wants, as long as the "orderByConsumed" flag is not set.  ^When the
9714 ** the "orderByConsumed" flag is unset, the query planner will add extra
9715 ** [bytecode] to ensure that the final results returned by the SQL query are
9716 ** ordered correctly.  The use of the "orderByConsumed" flag and the
9717 ** sqlite3_vtab_distinct() interface is merely an optimization.  ^Careful
9718 ** use of the sqlite3_vtab_distinct() interface and the "orderByConsumed"
9719 ** flag might help queries against a virtual table to run faster.  Being
9720 ** overly aggressive and setting the "orderByConsumed" flag when it is not
9721 ** valid to do so, on the other hand, might cause SQLite to return incorrect
9722 ** results.
9723 */
9724 SQLITE_API int sqlite3_vtab_distinct(sqlite3_index_info*);
9725 
9726 /*
9727 ** CAPI3REF: Identify and handle IN constraints in xBestIndex
9728 **
9729 ** This interface may only be used from within an
9730 ** [xBestIndex|xBestIndex() method] of a [virtual table] implementation.
9731 ** The result of invoking this interface from any other context is
9732 ** undefined and probably harmful.
9733 **
9734 ** ^(A constraint on a virtual table of the form
9735 ** "[IN operator|column IN (...)]" is
9736 ** communicated to the xBestIndex method as a
9737 ** [SQLITE_INDEX_CONSTRAINT_EQ] constraint.)^  If xBestIndex wants to use
9738 ** this constraint, it must set the corresponding
9739 ** aConstraintUsage[].argvIndex to a postive integer.  ^(Then, under
9740 ** the usual mode of handling IN operators, SQLite generates [bytecode]
9741 ** that invokes the [xFilter|xFilter() method] once for each value
9742 ** on the right-hand side of the IN operator.)^  Thus the virtual table
9743 ** only sees a single value from the right-hand side of the IN operator
9744 ** at a time.
9745 **
9746 ** In some cases, however, it would be advantageous for the virtual
9747 ** table to see all values on the right-hand of the IN operator all at
9748 ** once.  The sqlite3_vtab_in() interfaces facilitates this in two ways:
9749 **
9750 ** <ol>
9751 ** <li><p>
9752 **   ^A call to sqlite3_vtab_in(P,N,-1) will return true (non-zero)
9753 **   if and only if the [sqlite3_index_info|P->aConstraint][N] constraint
9754 **   is an [IN operator] that can be processed all at once.  ^In other words,
9755 **   sqlite3_vtab_in() with -1 in the third argument is a mechanism
9756 **   by which the virtual table can ask SQLite if all-at-once processing
9757 **   of the IN operator is even possible.
9758 **
9759 ** <li><p>
9760 **   ^A call to sqlite3_vtab_in(P,N,F) with F==1 or F==0 indicates
9761 **   to SQLite that the virtual table does or does not want to process
9762 **   the IN operator all-at-once, respectively.  ^Thus when the third
9763 **   parameter (F) is non-negative, this interface is the mechanism by
9764 **   which the virtual table tells SQLite how it wants to process the
9765 **   IN operator.
9766 ** </ol>
9767 **
9768 ** ^The sqlite3_vtab_in(P,N,F) interface can be invoked multiple times
9769 ** within the same xBestIndex method call.  ^For any given P,N pair,
9770 ** the return value from sqlite3_vtab_in(P,N,F) will always be the same
9771 ** within the same xBestIndex call.  ^If the interface returns true
9772 ** (non-zero), that means that the constraint is an IN operator
9773 ** that can be processed all-at-once.  ^If the constraint is not an IN
9774 ** operator or cannot be processed all-at-once, then the interface returns
9775 ** false.
9776 **
9777 ** ^(All-at-once processing of the IN operator is selected if both of the
9778 ** following conditions are met:
9779 **
9780 ** <ol>
9781 ** <li><p> The P->aConstraintUsage[N].argvIndex value is set to a positive
9782 ** integer.  This is how the virtual table tells SQLite that it wants to
9783 ** use the N-th constraint.
9784 **
9785 ** <li><p> The last call to sqlite3_vtab_in(P,N,F) for which F was
9786 ** non-negative had F>=1.
9787 ** </ol>)^
9788 **
9789 ** ^If either or both of the conditions above are false, then SQLite uses
9790 ** the traditional one-at-a-time processing strategy for the IN constraint.
9791 ** ^If both conditions are true, then the argvIndex-th parameter to the
9792 ** xFilter method will be an [sqlite3_value] that appears to be NULL,
9793 ** but which can be passed to [sqlite3_vtab_in_first()] and
9794 ** [sqlite3_vtab_in_next()] to find all values on the right-hand side
9795 ** of the IN constraint.
9796 */
9797 SQLITE_API int sqlite3_vtab_in(sqlite3_index_info*, int iCons, int bHandle);
9798 
9799 /*
9800 ** CAPI3REF: Find all elements on the right-hand side of an IN constraint.
9801 **
9802 ** These interfaces are only useful from within the
9803 ** [xFilter|xFilter() method] of a [virtual table] implementation.
9804 ** The result of invoking these interfaces from any other context
9805 ** is undefined and probably harmful.
9806 **
9807 ** The X parameter in a call to sqlite3_vtab_in_first(X,P) or
9808 ** sqlite3_vtab_in_next(X,P) should be one of the parameters to the
9809 ** xFilter method which invokes these routines, and specifically
9810 ** a parameter that was previously selected for all-at-once IN constraint
9811 ** processing use the [sqlite3_vtab_in()] interface in the
9812 ** [xBestIndex|xBestIndex method].  ^(If the X parameter is not
9813 ** an xFilter argument that was selected for all-at-once IN constraint
9814 ** processing, then these routines return [SQLITE_ERROR].)^
9815 **
9816 ** ^(Use these routines to access all values on the right-hand side
9817 ** of the IN constraint using code like the following:
9818 **
9819 ** <blockquote><pre>
9820 ** &nbsp;  for(rc=sqlite3_vtab_in_first(pList, &pVal);
9821 ** &nbsp;      rc==SQLITE_OK && pVal;
9822 ** &nbsp;      rc=sqlite3_vtab_in_next(pList, &pVal)
9823 ** &nbsp;  ){
9824 ** &nbsp;    // do something with pVal
9825 ** &nbsp;  }
9826 ** &nbsp;  if( rc!=SQLITE_OK ){
9827 ** &nbsp;    // an error has occurred
9828 ** &nbsp;  }
9829 ** </pre></blockquote>)^
9830 **
9831 ** ^On success, the sqlite3_vtab_in_first(X,P) and sqlite3_vtab_in_next(X,P)
9832 ** routines return SQLITE_OK and set *P to point to the first or next value
9833 ** on the RHS of the IN constraint.  ^If there are no more values on the
9834 ** right hand side of the IN constraint, then *P is set to NULL and these
9835 ** routines return [SQLITE_DONE].  ^The return value might be
9836 ** some other value, such as SQLITE_NOMEM, in the event of a malfunction.
9837 **
9838 ** The *ppOut values returned by these routines are only valid until the
9839 ** next call to either of these routines or until the end of the xFilter
9840 ** method from which these routines were called.  If the virtual table
9841 ** implementation needs to retain the *ppOut values for longer, it must make
9842 ** copies.  The *ppOut values are [protected sqlite3_value|protected].
9843 */
9844 SQLITE_API int sqlite3_vtab_in_first(sqlite3_value *pVal, sqlite3_value **ppOut);
9845 SQLITE_API int sqlite3_vtab_in_next(sqlite3_value *pVal, sqlite3_value **ppOut);
9846 
9847 /*
9848 ** CAPI3REF: Constraint values in xBestIndex()
9849 ** METHOD: sqlite3_index_info
9850 **
9851 ** This API may only be used from within the [xBestIndex|xBestIndex method]
9852 ** of a [virtual table] implementation. The result of calling this interface
9853 ** from outside of an xBestIndex method are undefined and probably harmful.
9854 **
9855 ** ^When the sqlite3_vtab_rhs_value(P,J,V) interface is invoked from within
9856 ** the [xBestIndex] method of a [virtual table] implementation, with P being
9857 ** a copy of the [sqlite3_index_info] object pointer passed into xBestIndex and
9858 ** J being a 0-based index into P->aConstraint[], then this routine
9859 ** attempts to set *V to the value of the right-hand operand of
9860 ** that constraint if the right-hand operand is known.  ^If the
9861 ** right-hand operand is not known, then *V is set to a NULL pointer.
9862 ** ^The sqlite3_vtab_rhs_value(P,J,V) interface returns SQLITE_OK if
9863 ** and only if *V is set to a value.  ^The sqlite3_vtab_rhs_value(P,J,V)
9864 ** inteface returns SQLITE_NOTFOUND if the right-hand side of the J-th
9865 ** constraint is not available.  ^The sqlite3_vtab_rhs_value() interface
9866 ** can return an result code other than SQLITE_OK or SQLITE_NOTFOUND if
9867 ** something goes wrong.
9868 **
9869 ** The sqlite3_vtab_rhs_value() interface is usually only successful if
9870 ** the right-hand operand of a constraint is a literal value in the original
9871 ** SQL statement.  If the right-hand operand is an expression or a reference
9872 ** to some other column or a [host parameter], then sqlite3_vtab_rhs_value()
9873 ** will probably return [SQLITE_NOTFOUND].
9874 **
9875 ** ^(Some constraints, such as [SQLITE_INDEX_CONSTRAINT_ISNULL] and
9876 ** [SQLITE_INDEX_CONSTRAINT_ISNOTNULL], have no right-hand operand.  For such
9877 ** constraints, sqlite3_vtab_rhs_value() always returns SQLITE_NOTFOUND.)^
9878 **
9879 ** ^The [sqlite3_value] object returned in *V is a protected sqlite3_value
9880 ** and remains valid for the duration of the xBestIndex method call.
9881 ** ^When xBestIndex returns, the sqlite3_value object returned by
9882 ** sqlite3_vtab_rhs_value() is automatically deallocated.
9883 **
9884 ** The "_rhs_" in the name of this routine is an abbreviation for
9885 ** "Right-Hand Side".
9886 */
9887 SQLITE_API int sqlite3_vtab_rhs_value(sqlite3_index_info*, int, sqlite3_value **ppVal);
9888 
9889 /*
9890 ** CAPI3REF: Conflict resolution modes
9891 ** KEYWORDS: {conflict resolution mode}
9892 **
9893 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
9894 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
9895 ** is for the SQL statement being evaluated.
9896 **
9897 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
9898 ** return value from the [sqlite3_set_authorizer()] callback and that
9899 ** [SQLITE_ABORT] is also a [result code].
9900 */
9901 #define SQLITE_ROLLBACK 1
9902 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
9903 #define SQLITE_FAIL     3
9904 /* #define SQLITE_ABORT 4  // Also an error code */
9905 #define SQLITE_REPLACE  5
9906 
9907 /*
9908 ** CAPI3REF: Prepared Statement Scan Status Opcodes
9909 ** KEYWORDS: {scanstatus options}
9910 **
9911 ** The following constants can be used for the T parameter to the
9912 ** [sqlite3_stmt_scanstatus(S,X,T,V)] interface.  Each constant designates a
9913 ** different metric for sqlite3_stmt_scanstatus() to return.
9914 **
9915 ** When the value returned to V is a string, space to hold that string is
9916 ** managed by the prepared statement S and will be automatically freed when
9917 ** S is finalized.
9918 **
9919 ** Not all values are available for all query elements. When a value is
9920 ** not available, the output variable is set to -1 if the value is numeric,
9921 ** or to NULL if it is a string (SQLITE_SCANSTAT_NAME).
9922 **
9923 ** <dl>
9924 ** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
9925 ** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be
9926 ** set to the total number of times that the X-th loop has run.</dd>
9927 **
9928 ** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
9929 ** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set
9930 ** to the total number of rows examined by all iterations of the X-th loop.</dd>
9931 **
9932 ** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
9933 ** <dd>^The "double" variable pointed to by the V parameter will be set to the
9934 ** query planner's estimate for the average number of rows output from each
9935 ** iteration of the X-th loop.  If the query planner's estimates was accurate,
9936 ** then this value will approximate the quotient NVISIT/NLOOP and the
9937 ** product of this value for all prior loops with the same SELECTID will
9938 ** be the NLOOP value for the current loop.
9939 **
9940 ** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
9941 ** <dd>^The "const char *" variable pointed to by the V parameter will be set
9942 ** to a zero-terminated UTF-8 string containing the name of the index or table
9943 ** used for the X-th loop.
9944 **
9945 ** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
9946 ** <dd>^The "const char *" variable pointed to by the V parameter will be set
9947 ** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
9948 ** description for the X-th loop.
9949 **
9950 ** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECTID</dt>
9951 ** <dd>^The "int" variable pointed to by the V parameter will be set to the
9952 ** id for the X-th query plan element. The id value is unique within the
9953 ** statement. The select-id is the same value as is output in the first
9954 ** column of an [EXPLAIN QUERY PLAN] query.
9955 **
9956 ** [[SQLITE_SCANSTAT_PARENTID]] <dt>SQLITE_SCANSTAT_PARENTID</dt>
9957 ** <dd>The "int" variable pointed to by the V parameter will be set to the
9958 ** the id of the parent of the current query element, if applicable, or
9959 ** to zero if the query element has no parent. This is the same value as
9960 ** returned in the second column of an [EXPLAIN QUERY PLAN] query.
9961 **
9962 ** [[SQLITE_SCANSTAT_NCYCLE]] <dt>SQLITE_SCANSTAT_NCYCLE</dt>
9963 ** <dd>The sqlite3_int64 output value is set to the number of cycles,
9964 ** according to the processor time-stamp counter, that elapsed while the
9965 ** query element was being processed. This value is not available for
9966 ** all query elements - if it is unavailable the output variable is
9967 ** set to -1.
9968 ** </dl>
9969 */
9970 #define SQLITE_SCANSTAT_NLOOP    0
9971 #define SQLITE_SCANSTAT_NVISIT   1
9972 #define SQLITE_SCANSTAT_EST      2
9973 #define SQLITE_SCANSTAT_NAME     3
9974 #define SQLITE_SCANSTAT_EXPLAIN  4
9975 #define SQLITE_SCANSTAT_SELECTID 5
9976 #define SQLITE_SCANSTAT_PARENTID 6
9977 #define SQLITE_SCANSTAT_NCYCLE   7
9978 
9979 /*
9980 ** CAPI3REF: Prepared Statement Scan Status
9981 ** METHOD: sqlite3_stmt
9982 **
9983 ** These interfaces return information about the predicted and measured
9984 ** performance for pStmt.  Advanced applications can use this
9985 ** interface to compare the predicted and the measured performance and
9986 ** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
9987 **
9988 ** Since this interface is expected to be rarely used, it is only
9989 ** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
9990 ** compile-time option.
9991 **
9992 ** The "iScanStatusOp" parameter determines which status information to return.
9993 ** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
9994 ** of this interface is undefined. ^The requested measurement is written into
9995 ** a variable pointed to by the "pOut" parameter.
9996 **
9997 ** The "flags" parameter must be passed a mask of flags. At present only
9998 ** one flag is defined - SQLITE_SCANSTAT_COMPLEX. If SQLITE_SCANSTAT_COMPLEX
9999 ** is specified, then status information is available for all elements
10000 ** of a query plan that are reported by "EXPLAIN QUERY PLAN" output. If
10001 ** SQLITE_SCANSTAT_COMPLEX is not specified, then only query plan elements
10002 ** that correspond to query loops (the "SCAN..." and "SEARCH..." elements of
10003 ** the EXPLAIN QUERY PLAN output) are available. Invoking API
10004 ** sqlite3_stmt_scanstatus() is equivalent to calling
10005 ** sqlite3_stmt_scanstatus_v2() with a zeroed flags parameter.
10006 **
10007 ** Parameter "idx" identifies the specific query element to retrieve statistics
10008 ** for. Query elements are numbered starting from zero. A value of -1 may be
10009 ** to query for statistics regarding the entire query. ^If idx is out of range
10010 ** - less than -1 or greater than or equal to the total number of query
10011 ** elements used to implement the statement - a non-zero value is returned and
10012 ** the variable that pOut points to is unchanged.
10013 **
10014 ** See also: [sqlite3_stmt_scanstatus_reset()]
10015 */
10016 SQLITE_API int sqlite3_stmt_scanstatus(
10017   sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
10018   int idx,                  /* Index of loop to report on */
10019   int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
10020   void *pOut                /* Result written here */
10021 );
10022 SQLITE_API int sqlite3_stmt_scanstatus_v2(
10023   sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
10024   int idx,                  /* Index of loop to report on */
10025   int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
10026   int flags,                /* Mask of flags defined below */
10027   void *pOut                /* Result written here */
10028 );
10029 
10030 /*
10031 ** CAPI3REF: Prepared Statement Scan Status
10032 ** KEYWORDS: {scan status flags}
10033 */
10034 #define SQLITE_SCANSTAT_COMPLEX 0x0001
10035 
10036 /*
10037 ** CAPI3REF: Zero Scan-Status Counters
10038 ** METHOD: sqlite3_stmt
10039 **
10040 ** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
10041 **
10042 ** This API is only available if the library is built with pre-processor
10043 ** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
10044 */
10045 SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
10046 
10047 /*
10048 ** CAPI3REF: Flush caches to disk mid-transaction
10049 ** METHOD: sqlite3
10050 **
10051 ** ^If a write-transaction is open on [database connection] D when the
10052 ** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
10053 ** pages in the pager-cache that are not currently in use are written out
10054 ** to disk. A dirty page may be in use if a database cursor created by an
10055 ** active SQL statement is reading from it, or if it is page 1 of a database
10056 ** file (page 1 is always "in use").  ^The [sqlite3_db_cacheflush(D)]
10057 ** interface flushes caches for all schemas - "main", "temp", and
10058 ** any [attached] databases.
10059 **
10060 ** ^If this function needs to obtain extra database locks before dirty pages
10061 ** can be flushed to disk, it does so. ^If those locks cannot be obtained
10062 ** immediately and there is a busy-handler callback configured, it is invoked
10063 ** in the usual manner. ^If the required lock still cannot be obtained, then
10064 ** the database is skipped and an attempt made to flush any dirty pages
10065 ** belonging to the next (if any) database. ^If any databases are skipped
10066 ** because locks cannot be obtained, but no other error occurs, this
10067 ** function returns SQLITE_BUSY.
10068 **
10069 ** ^If any other error occurs while flushing dirty pages to disk (for
10070 ** example an IO error or out-of-memory condition), then processing is
10071 ** abandoned and an SQLite [error code] is returned to the caller immediately.
10072 **
10073 ** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
10074 **
10075 ** ^This function does not set the database handle error code or message
10076 ** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
10077 */
10078 SQLITE_API int sqlite3_db_cacheflush(sqlite3*);
10079 
10080 /*
10081 ** CAPI3REF: The pre-update hook.
10082 ** METHOD: sqlite3
10083 **
10084 ** ^These interfaces are only available if SQLite is compiled using the
10085 ** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
10086 **
10087 ** ^The [sqlite3_preupdate_hook()] interface registers a callback function
10088 ** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
10089 ** on a database table.
10090 ** ^At most one preupdate hook may be registered at a time on a single
10091 ** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
10092 ** the previous setting.
10093 ** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
10094 ** with a NULL pointer as the second parameter.
10095 ** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
10096 ** the first parameter to callbacks.
10097 **
10098 ** ^The preupdate hook only fires for changes to real database tables; the
10099 ** preupdate hook is not invoked for changes to [virtual tables] or to
10100 ** system tables like sqlite_sequence or sqlite_stat1.
10101 **
10102 ** ^The second parameter to the preupdate callback is a pointer to
10103 ** the [database connection] that registered the preupdate hook.
10104 ** ^The third parameter to the preupdate callback is one of the constants
10105 ** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
10106 ** kind of update operation that is about to occur.
10107 ** ^(The fourth parameter to the preupdate callback is the name of the
10108 ** database within the database connection that is being modified.  This
10109 ** will be "main" for the main database or "temp" for TEMP tables or
10110 ** the name given after the AS keyword in the [ATTACH] statement for attached
10111 ** databases.)^
10112 ** ^The fifth parameter to the preupdate callback is the name of the
10113 ** table that is being modified.
10114 **
10115 ** For an UPDATE or DELETE operation on a [rowid table], the sixth
10116 ** parameter passed to the preupdate callback is the initial [rowid] of the
10117 ** row being modified or deleted. For an INSERT operation on a rowid table,
10118 ** or any operation on a WITHOUT ROWID table, the value of the sixth
10119 ** parameter is undefined. For an INSERT or UPDATE on a rowid table the
10120 ** seventh parameter is the final rowid value of the row being inserted
10121 ** or updated. The value of the seventh parameter passed to the callback
10122 ** function is not defined for operations on WITHOUT ROWID tables, or for
10123 ** DELETE operations on rowid tables.
10124 **
10125 ** ^The sqlite3_preupdate_hook(D,C,P) function returns the P argument from
10126 ** the previous call on the same [database connection] D, or NULL for
10127 ** the first call on D.
10128 **
10129 ** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
10130 ** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
10131 ** provide additional information about a preupdate event. These routines
10132 ** may only be called from within a preupdate callback.  Invoking any of
10133 ** these routines from outside of a preupdate callback or with a
10134 ** [database connection] pointer that is different from the one supplied
10135 ** to the preupdate callback results in undefined and probably undesirable
10136 ** behavior.
10137 **
10138 ** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
10139 ** in the row that is being inserted, updated, or deleted.
10140 **
10141 ** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
10142 ** a [protected sqlite3_value] that contains the value of the Nth column of
10143 ** the table row before it is updated.  The N parameter must be between 0
10144 ** and one less than the number of columns or the behavior will be
10145 ** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
10146 ** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
10147 ** behavior is undefined.  The [sqlite3_value] that P points to
10148 ** will be destroyed when the preupdate callback returns.
10149 **
10150 ** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
10151 ** a [protected sqlite3_value] that contains the value of the Nth column of
10152 ** the table row after it is updated.  The N parameter must be between 0
10153 ** and one less than the number of columns or the behavior will be
10154 ** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
10155 ** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
10156 ** behavior is undefined.  The [sqlite3_value] that P points to
10157 ** will be destroyed when the preupdate callback returns.
10158 **
10159 ** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
10160 ** callback was invoked as a result of a direct insert, update, or delete
10161 ** operation; or 1 for inserts, updates, or deletes invoked by top-level
10162 ** triggers; or 2 for changes resulting from triggers called by top-level
10163 ** triggers; and so forth.
10164 **
10165 ** When the [sqlite3_blob_write()] API is used to update a blob column,
10166 ** the pre-update hook is invoked with SQLITE_DELETE. This is because the
10167 ** in this case the new values are not available. In this case, when a
10168 ** callback made with op==SQLITE_DELETE is actuall a write using the
10169 ** sqlite3_blob_write() API, the [sqlite3_preupdate_blobwrite()] returns
10170 ** the index of the column being written. In other cases, where the
10171 ** pre-update hook is being invoked for some other reason, including a
10172 ** regular DELETE, sqlite3_preupdate_blobwrite() returns -1.
10173 **
10174 ** See also:  [sqlite3_update_hook()]
10175 */
10176 #if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
10177 SQLITE_API void *sqlite3_preupdate_hook(
10178   sqlite3 *db,
10179   void(*xPreUpdate)(
10180     void *pCtx,                   /* Copy of third arg to preupdate_hook() */
10181     sqlite3 *db,                  /* Database handle */
10182     int op,                       /* SQLITE_UPDATE, DELETE or INSERT */
10183     char const *zDb,              /* Database name */
10184     char const *zName,            /* Table name */
10185     sqlite3_int64 iKey1,          /* Rowid of row about to be deleted/updated */
10186     sqlite3_int64 iKey2           /* New rowid value (for a rowid UPDATE) */
10187   ),
10188   void*
10189 );
10190 SQLITE_API int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
10191 SQLITE_API int sqlite3_preupdate_count(sqlite3 *);
10192 SQLITE_API int sqlite3_preupdate_depth(sqlite3 *);
10193 SQLITE_API int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
10194 SQLITE_API int sqlite3_preupdate_blobwrite(sqlite3 *);
10195 #endif
10196 
10197 /*
10198 ** CAPI3REF: Low-level system error code
10199 ** METHOD: sqlite3
10200 **
10201 ** ^Attempt to return the underlying operating system error code or error
10202 ** number that caused the most recent I/O error or failure to open a file.
10203 ** The return value is OS-dependent.  For example, on unix systems, after
10204 ** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
10205 ** called to get back the underlying "errno" that caused the problem, such
10206 ** as ENOSPC, EAUTH, EISDIR, and so forth.
10207 */
10208 SQLITE_API int sqlite3_system_errno(sqlite3*);
10209 
10210 /*
10211 ** CAPI3REF: Database Snapshot
10212 ** KEYWORDS: {snapshot} {sqlite3_snapshot}
10213 **
10214 ** An instance of the snapshot object records the state of a [WAL mode]
10215 ** database for some specific point in history.
10216 **
10217 ** In [WAL mode], multiple [database connections] that are open on the
10218 ** same database file can each be reading a different historical version
10219 ** of the database file.  When a [database connection] begins a read
10220 ** transaction, that connection sees an unchanging copy of the database
10221 ** as it existed for the point in time when the transaction first started.
10222 ** Subsequent changes to the database from other connections are not seen
10223 ** by the reader until a new read transaction is started.
10224 **
10225 ** The sqlite3_snapshot object records state information about an historical
10226 ** version of the database file so that it is possible to later open a new read
10227 ** transaction that sees that historical version of the database rather than
10228 ** the most recent version.
10229 */
10230 typedef struct sqlite3_snapshot {
10231   unsigned char hidden[48];
10232 } sqlite3_snapshot;
10233 
10234 /*
10235 ** CAPI3REF: Record A Database Snapshot
10236 ** CONSTRUCTOR: sqlite3_snapshot
10237 **
10238 ** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
10239 ** new [sqlite3_snapshot] object that records the current state of
10240 ** schema S in database connection D.  ^On success, the
10241 ** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
10242 ** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
10243 ** If there is not already a read-transaction open on schema S when
10244 ** this function is called, one is opened automatically.
10245 **
10246 ** The following must be true for this function to succeed. If any of
10247 ** the following statements are false when sqlite3_snapshot_get() is
10248 ** called, SQLITE_ERROR is returned. The final value of *P is undefined
10249 ** in this case.
10250 **
10251 ** <ul>
10252 **   <li> The database handle must not be in [autocommit mode].
10253 **
10254 **   <li> Schema S of [database connection] D must be a [WAL mode] database.
10255 **
10256 **   <li> There must not be a write transaction open on schema S of database
10257 **        connection D.
10258 **
10259 **   <li> One or more transactions must have been written to the current wal
10260 **        file since it was created on disk (by any connection). This means
10261 **        that a snapshot cannot be taken on a wal mode database with no wal
10262 **        file immediately after it is first opened. At least one transaction
10263 **        must be written to it first.
10264 ** </ul>
10265 **
10266 ** This function may also return SQLITE_NOMEM.  If it is called with the
10267 ** database handle in autocommit mode but fails for some other reason,
10268 ** whether or not a read transaction is opened on schema S is undefined.
10269 **
10270 ** The [sqlite3_snapshot] object returned from a successful call to
10271 ** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
10272 ** to avoid a memory leak.
10273 **
10274 ** The [sqlite3_snapshot_get()] interface is only available when the
10275 ** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
10276 */
10277 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
10278   sqlite3 *db,
10279   const char *zSchema,
10280   sqlite3_snapshot **ppSnapshot
10281 );
10282 
10283 /*
10284 ** CAPI3REF: Start a read transaction on an historical snapshot
10285 ** METHOD: sqlite3_snapshot
10286 **
10287 ** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read
10288 ** transaction or upgrades an existing one for schema S of
10289 ** [database connection] D such that the read transaction refers to
10290 ** historical [snapshot] P, rather than the most recent change to the
10291 ** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK
10292 ** on success or an appropriate [error code] if it fails.
10293 **
10294 ** ^In order to succeed, the database connection must not be in
10295 ** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there
10296 ** is already a read transaction open on schema S, then the database handle
10297 ** must have no active statements (SELECT statements that have been passed
10298 ** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()).
10299 ** SQLITE_ERROR is returned if either of these conditions is violated, or
10300 ** if schema S does not exist, or if the snapshot object is invalid.
10301 **
10302 ** ^A call to sqlite3_snapshot_open() will fail to open if the specified
10303 ** snapshot has been overwritten by a [checkpoint]. In this case
10304 ** SQLITE_ERROR_SNAPSHOT is returned.
10305 **
10306 ** If there is already a read transaction open when this function is
10307 ** invoked, then the same read transaction remains open (on the same
10308 ** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT
10309 ** is returned. If another error code - for example SQLITE_PROTOCOL or an
10310 ** SQLITE_IOERR error code - is returned, then the final state of the
10311 ** read transaction is undefined. If SQLITE_OK is returned, then the
10312 ** read transaction is now open on database snapshot P.
10313 **
10314 ** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
10315 ** database connection D does not know that the database file for
10316 ** schema S is in [WAL mode].  A database connection might not know
10317 ** that the database file is in [WAL mode] if there has been no prior
10318 ** I/O on that database connection, or if the database entered [WAL mode]
10319 ** after the most recent I/O on the database connection.)^
10320 ** (Hint: Run "[PRAGMA application_id]" against a newly opened
10321 ** database connection in order to make it ready to use snapshots.)
10322 **
10323 ** The [sqlite3_snapshot_open()] interface is only available when the
10324 ** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
10325 */
10326 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
10327   sqlite3 *db,
10328   const char *zSchema,
10329   sqlite3_snapshot *pSnapshot
10330 );
10331 
10332 /*
10333 ** CAPI3REF: Destroy a snapshot
10334 ** DESTRUCTOR: sqlite3_snapshot
10335 **
10336 ** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
10337 ** The application must eventually free every [sqlite3_snapshot] object
10338 ** using this routine to avoid a memory leak.
10339 **
10340 ** The [sqlite3_snapshot_free()] interface is only available when the
10341 ** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
10342 */
10343 SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
10344 
10345 /*
10346 ** CAPI3REF: Compare the ages of two snapshot handles.
10347 ** METHOD: sqlite3_snapshot
10348 **
10349 ** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
10350 ** of two valid snapshot handles.
10351 **
10352 ** If the two snapshot handles are not associated with the same database
10353 ** file, the result of the comparison is undefined.
10354 **
10355 ** Additionally, the result of the comparison is only valid if both of the
10356 ** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
10357 ** last time the wal file was deleted. The wal file is deleted when the
10358 ** database is changed back to rollback mode or when the number of database
10359 ** clients drops to zero. If either snapshot handle was obtained before the
10360 ** wal file was last deleted, the value returned by this function
10361 ** is undefined.
10362 **
10363 ** Otherwise, this API returns a negative value if P1 refers to an older
10364 ** snapshot than P2, zero if the two handles refer to the same database
10365 ** snapshot, and a positive value if P1 is a newer snapshot than P2.
10366 **
10367 ** This interface is only available if SQLite is compiled with the
10368 ** [SQLITE_ENABLE_SNAPSHOT] option.
10369 */
10370 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
10371   sqlite3_snapshot *p1,
10372   sqlite3_snapshot *p2
10373 );
10374 
10375 /*
10376 ** CAPI3REF: Recover snapshots from a wal file
10377 ** METHOD: sqlite3_snapshot
10378 **
10379 ** If a [WAL file] remains on disk after all database connections close
10380 ** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control]
10381 ** or because the last process to have the database opened exited without
10382 ** calling [sqlite3_close()]) and a new connection is subsequently opened
10383 ** on that database and [WAL file], the [sqlite3_snapshot_open()] interface
10384 ** will only be able to open the last transaction added to the WAL file
10385 ** even though the WAL file contains other valid transactions.
10386 **
10387 ** This function attempts to scan the WAL file associated with database zDb
10388 ** of database handle db and make all valid snapshots available to
10389 ** sqlite3_snapshot_open(). It is an error if there is already a read
10390 ** transaction open on the database, or if the database is not a WAL mode
10391 ** database.
10392 **
10393 ** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
10394 **
10395 ** This interface is only available if SQLite is compiled with the
10396 ** [SQLITE_ENABLE_SNAPSHOT] option.
10397 */
10398 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
10399 
10400 /*
10401 ** CAPI3REF: Serialize a database
10402 **
10403 ** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory
10404 ** that is a serialization of the S database on [database connection] D.
10405 ** If P is not a NULL pointer, then the size of the database in bytes
10406 ** is written into *P.
10407 **
10408 ** For an ordinary on-disk database file, the serialization is just a
10409 ** copy of the disk file.  For an in-memory database or a "TEMP" database,
10410 ** the serialization is the same sequence of bytes which would be written
10411 ** to disk if that database where backed up to disk.
10412 **
10413 ** The usual case is that sqlite3_serialize() copies the serialization of
10414 ** the database into memory obtained from [sqlite3_malloc64()] and returns
10415 ** a pointer to that memory.  The caller is responsible for freeing the
10416 ** returned value to avoid a memory leak.  However, if the F argument
10417 ** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
10418 ** are made, and the sqlite3_serialize() function will return a pointer
10419 ** to the contiguous memory representation of the database that SQLite
10420 ** is currently using for that database, or NULL if the no such contiguous
10421 ** memory representation of the database exists.  A contiguous memory
10422 ** representation of the database will usually only exist if there has
10423 ** been a prior call to [sqlite3_deserialize(D,S,...)] with the same
10424 ** values of D and S.
10425 ** The size of the database is written into *P even if the
10426 ** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
10427 ** of the database exists.
10428 **
10429 ** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
10430 ** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
10431 ** allocation error occurs.
10432 **
10433 ** This interface is omitted if SQLite is compiled with the
10434 ** [SQLITE_OMIT_DESERIALIZE] option.
10435 */
10436 SQLITE_API unsigned char *sqlite3_serialize(
10437   sqlite3 *db,           /* The database connection */
10438   const char *zSchema,   /* Which DB to serialize. ex: "main", "temp", ... */
10439   sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */
10440   unsigned int mFlags    /* Zero or more SQLITE_SERIALIZE_* flags */
10441 );
10442 
10443 /*
10444 ** CAPI3REF: Flags for sqlite3_serialize
10445 **
10446 ** Zero or more of the following constants can be OR-ed together for
10447 ** the F argument to [sqlite3_serialize(D,S,P,F)].
10448 **
10449 ** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return
10450 ** a pointer to contiguous in-memory database that it is currently using,
10451 ** without making a copy of the database.  If SQLite is not currently using
10452 ** a contiguous in-memory database, then this option causes
10453 ** [sqlite3_serialize()] to return a NULL pointer.  SQLite will only be
10454 ** using a contiguous in-memory database if it has been initialized by a
10455 ** prior call to [sqlite3_deserialize()].
10456 */
10457 #define SQLITE_SERIALIZE_NOCOPY 0x001   /* Do no memory allocations */
10458 
10459 /*
10460 ** CAPI3REF: Deserialize a database
10461 **
10462 ** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
10463 ** [database connection] D to disconnect from database S and then
10464 ** reopen S as an in-memory database based on the serialization contained
10465 ** in P.  The serialized database P is N bytes in size.  M is the size of
10466 ** the buffer P, which might be larger than N.  If M is larger than N, and
10467 ** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
10468 ** permitted to add content to the in-memory database as long as the total
10469 ** size does not exceed M bytes.
10470 **
10471 ** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
10472 ** invoke sqlite3_free() on the serialization buffer when the database
10473 ** connection closes.  If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
10474 ** SQLite will try to increase the buffer size using sqlite3_realloc64()
10475 ** if writes on the database cause it to grow larger than M bytes.
10476 **
10477 ** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
10478 ** database is currently in a read transaction or is involved in a backup
10479 ** operation.
10480 **
10481 ** It is not possible to deserialized into the TEMP database.  If the
10482 ** S argument to sqlite3_deserialize(D,S,P,N,M,F) is "temp" then the
10483 ** function returns SQLITE_ERROR.
10484 **
10485 ** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
10486 ** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
10487 ** [sqlite3_free()] is invoked on argument P prior to returning.
10488 **
10489 ** This interface is omitted if SQLite is compiled with the
10490 ** [SQLITE_OMIT_DESERIALIZE] option.
10491 */
10492 SQLITE_API int sqlite3_deserialize(
10493   sqlite3 *db,            /* The database connection */
10494   const char *zSchema,    /* Which DB to reopen with the deserialization */
10495   unsigned char *pData,   /* The serialized database content */
10496   sqlite3_int64 szDb,     /* Number bytes in the deserialization */
10497   sqlite3_int64 szBuf,    /* Total size of buffer pData[] */
10498   unsigned mFlags         /* Zero or more SQLITE_DESERIALIZE_* flags */
10499 );
10500 
10501 /*
10502 ** CAPI3REF: Flags for sqlite3_deserialize()
10503 **
10504 ** The following are allowed values for 6th argument (the F argument) to
10505 ** the [sqlite3_deserialize(D,S,P,N,M,F)] interface.
10506 **
10507 ** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
10508 ** in the P argument is held in memory obtained from [sqlite3_malloc64()]
10509 ** and that SQLite should take ownership of this memory and automatically
10510 ** free it when it has finished using it.  Without this flag, the caller
10511 ** is responsible for freeing any dynamically allocated memory.
10512 **
10513 ** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
10514 ** grow the size of the database using calls to [sqlite3_realloc64()].  This
10515 ** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
10516 ** Without this flag, the deserialized database cannot increase in size beyond
10517 ** the number of bytes specified by the M parameter.
10518 **
10519 ** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
10520 ** should be treated as read-only.
10521 */
10522 #define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
10523 #define SQLITE_DESERIALIZE_RESIZEABLE  2 /* Resize using sqlite3_realloc64() */
10524 #define SQLITE_DESERIALIZE_READONLY    4 /* Database is read-only */
10525 
10526 /*
10527 ** Undo the hack that converts floating point types to integer for
10528 ** builds on processors without floating point support.
10529 */
10530 #ifdef SQLITE_OMIT_FLOATING_POINT
10531 # undef double
10532 #endif
10533 
10534 #if defined(__wasi__)
10535 # undef SQLITE_WASI
10536 # define SQLITE_WASI 1
10537 # undef SQLITE_OMIT_WAL
10538 # define SQLITE_OMIT_WAL 1/* because it requires shared memory APIs */
10539 # ifndef SQLITE_OMIT_LOAD_EXTENSION
10540 #  define SQLITE_OMIT_LOAD_EXTENSION
10541 # endif
10542 # ifndef SQLITE_THREADSAFE
10543 #  define SQLITE_THREADSAFE 0
10544 # endif
10545 #endif
10546 
10547 #ifdef __cplusplus
10548 }  /* End of the 'extern "C"' block */
10549 #endif
10550 #endif /* SQLITE3_H */
10551 
10552 /******** Begin file sqlite3rtree.h *********/
10553 /*
10554 ** 2010 August 30
10555 **
10556 ** The author disclaims copyright to this source code.  In place of
10557 ** a legal notice, here is a blessing:
10558 **
10559 **    May you do good and not evil.
10560 **    May you find forgiveness for yourself and forgive others.
10561 **    May you share freely, never taking more than you give.
10562 **
10563 *************************************************************************
10564 */
10565 
10566 #ifndef _SQLITE3RTREE_H_
10567 #define _SQLITE3RTREE_H_
10568 
10569 
10570 #ifdef __cplusplus
10571 extern "C" {
10572 #endif
10573 
10574 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
10575 typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
10576 
10577 /* The double-precision datatype used by RTree depends on the
10578 ** SQLITE_RTREE_INT_ONLY compile-time option.
10579 */
10580 #ifdef SQLITE_RTREE_INT_ONLY
10581   typedef sqlite3_int64 sqlite3_rtree_dbl;
10582 #else
10583   typedef double sqlite3_rtree_dbl;
10584 #endif
10585 
10586 /*
10587 ** Register a geometry callback named zGeom that can be used as part of an
10588 ** R-Tree geometry query as follows:
10589 **
10590 **   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
10591 */
10592 SQLITE_API int sqlite3_rtree_geometry_callback(
10593   sqlite3 *db,
10594   const char *zGeom,
10595   int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
10596   void *pContext
10597 );
10598 
10599 
10600 /*
10601 ** A pointer to a structure of the following type is passed as the first
10602 ** argument to callbacks registered using rtree_geometry_callback().
10603 */
10604 struct sqlite3_rtree_geometry {
10605   void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
10606   int nParam;                     /* Size of array aParam[] */
10607   sqlite3_rtree_dbl *aParam;      /* Parameters passed to SQL geom function */
10608   void *pUser;                    /* Callback implementation user data */
10609   void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
10610 };
10611 
10612 /*
10613 ** Register a 2nd-generation geometry callback named zScore that can be
10614 ** used as part of an R-Tree geometry query as follows:
10615 **
10616 **   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
10617 */
10618 SQLITE_API int sqlite3_rtree_query_callback(
10619   sqlite3 *db,
10620   const char *zQueryFunc,
10621   int (*xQueryFunc)(sqlite3_rtree_query_info*),
10622   void *pContext,
10623   void (*xDestructor)(void*)
10624 );
10625 
10626 
10627 /*
10628 ** A pointer to a structure of the following type is passed as the
10629 ** argument to scored geometry callback registered using
10630 ** sqlite3_rtree_query_callback().
10631 **
10632 ** Note that the first 5 fields of this structure are identical to
10633 ** sqlite3_rtree_geometry.  This structure is a subclass of
10634 ** sqlite3_rtree_geometry.
10635 */
10636 struct sqlite3_rtree_query_info {
10637   void *pContext;                   /* pContext from when function registered */
10638   int nParam;                       /* Number of function parameters */
10639   sqlite3_rtree_dbl *aParam;        /* value of function parameters */
10640   void *pUser;                      /* callback can use this, if desired */
10641   void (*xDelUser)(void*);          /* function to free pUser */
10642   sqlite3_rtree_dbl *aCoord;        /* Coordinates of node or entry to check */
10643   unsigned int *anQueue;            /* Number of pending entries in the queue */
10644   int nCoord;                       /* Number of coordinates */
10645   int iLevel;                       /* Level of current node or entry */
10646   int mxLevel;                      /* The largest iLevel value in the tree */
10647   sqlite3_int64 iRowid;             /* Rowid for current entry */
10648   sqlite3_rtree_dbl rParentScore;   /* Score of parent node */
10649   int eParentWithin;                /* Visibility of parent node */
10650   int eWithin;                      /* OUT: Visibility */
10651   sqlite3_rtree_dbl rScore;         /* OUT: Write the score here */
10652   /* The following fields are only available in 3.8.11 and later */
10653   sqlite3_value **apSqlParam;       /* Original SQL values of parameters */
10654 };
10655 
10656 /*
10657 ** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
10658 */
10659 #define NOT_WITHIN       0   /* Object completely outside of query region */
10660 #define PARTLY_WITHIN    1   /* Object partially overlaps query region */
10661 #define FULLY_WITHIN     2   /* Object fully contained within query region */
10662 
10663 
10664 #ifdef __cplusplus
10665 }  /* end of the 'extern "C"' block */
10666 #endif
10667 
10668 #endif  /* ifndef _SQLITE3RTREE_H_ */
10669 
10670 /******** End of sqlite3rtree.h *********/
10671 /******** Begin file sqlite3session.h *********/
10672 
10673 #if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
10674 #define __SQLITESESSION_H_ 1
10675 
10676 /*
10677 ** Make sure we can call this stuff from C++.
10678 */
10679 #ifdef __cplusplus
10680 extern "C" {
10681 #endif
10682 
10683 
10684 /*
10685 ** CAPI3REF: Session Object Handle
10686 **
10687 ** An instance of this object is a [session] that can be used to
10688 ** record changes to a database.
10689 */
10690 typedef struct sqlite3_session sqlite3_session;
10691 
10692 /*
10693 ** CAPI3REF: Changeset Iterator Handle
10694 **
10695 ** An instance of this object acts as a cursor for iterating
10696 ** over the elements of a [changeset] or [patchset].
10697 */
10698 typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
10699 
10700 /*
10701 ** CAPI3REF: Create A New Session Object
10702 ** CONSTRUCTOR: sqlite3_session
10703 **
10704 ** Create a new session object attached to database handle db. If successful,
10705 ** a pointer to the new object is written to *ppSession and SQLITE_OK is
10706 ** returned. If an error occurs, *ppSession is set to NULL and an SQLite
10707 ** error code (e.g. SQLITE_NOMEM) is returned.
10708 **
10709 ** It is possible to create multiple session objects attached to a single
10710 ** database handle.
10711 **
10712 ** Session objects created using this function should be deleted using the
10713 ** [sqlite3session_delete()] function before the database handle that they
10714 ** are attached to is itself closed. If the database handle is closed before
10715 ** the session object is deleted, then the results of calling any session
10716 ** module function, including [sqlite3session_delete()] on the session object
10717 ** are undefined.
10718 **
10719 ** Because the session module uses the [sqlite3_preupdate_hook()] API, it
10720 ** is not possible for an application to register a pre-update hook on a
10721 ** database handle that has one or more session objects attached. Nor is
10722 ** it possible to create a session object attached to a database handle for
10723 ** which a pre-update hook is already defined. The results of attempting
10724 ** either of these things are undefined.
10725 **
10726 ** The session object will be used to create changesets for tables in
10727 ** database zDb, where zDb is either "main", or "temp", or the name of an
10728 ** attached database. It is not an error if database zDb is not attached
10729 ** to the database when the session object is created.
10730 */
10731 SQLITE_API int sqlite3session_create(
10732   sqlite3 *db,                    /* Database handle */
10733   const char *zDb,                /* Name of db (e.g. "main") */
10734   sqlite3_session **ppSession     /* OUT: New session object */
10735 );
10736 
10737 /*
10738 ** CAPI3REF: Delete A Session Object
10739 ** DESTRUCTOR: sqlite3_session
10740 **
10741 ** Delete a session object previously allocated using
10742 ** [sqlite3session_create()]. Once a session object has been deleted, the
10743 ** results of attempting to use pSession with any other session module
10744 ** function are undefined.
10745 **
10746 ** Session objects must be deleted before the database handle to which they
10747 ** are attached is closed. Refer to the documentation for
10748 ** [sqlite3session_create()] for details.
10749 */
10750 SQLITE_API void sqlite3session_delete(sqlite3_session *pSession);
10751 
10752 /*
10753 ** CAPIREF: Conigure a Session Object
10754 ** METHOD: sqlite3_session
10755 **
10756 ** This method is used to configure a session object after it has been
10757 ** created. At present the only valid value for the second parameter is
10758 ** [SQLITE_SESSION_OBJCONFIG_SIZE].
10759 **
10760 ** Arguments for sqlite3session_object_config()
10761 **
10762 ** The following values may passed as the the 4th parameter to
10763 ** sqlite3session_object_config().
10764 **
10765 ** <dt>SQLITE_SESSION_OBJCONFIG_SIZE <dd>
10766 **   This option is used to set, clear or query the flag that enables
10767 **   the [sqlite3session_changeset_size()] API. Because it imposes some
10768 **   computational overhead, this API is disabled by default. Argument
10769 **   pArg must point to a value of type (int). If the value is initially
10770 **   0, then the sqlite3session_changeset_size() API is disabled. If it
10771 **   is greater than 0, then the same API is enabled. Or, if the initial
10772 **   value is less than zero, no change is made. In all cases the (int)
10773 **   variable is set to 1 if the sqlite3session_changeset_size() API is
10774 **   enabled following the current call, or 0 otherwise.
10775 **
10776 **   It is an error (SQLITE_MISUSE) to attempt to modify this setting after
10777 **   the first table has been attached to the session object.
10778 */
10779 SQLITE_API int sqlite3session_object_config(sqlite3_session*, int op, void *pArg);
10780 
10781 /*
10782 */
10783 #define SQLITE_SESSION_OBJCONFIG_SIZE 1
10784 
10785 /*
10786 ** CAPI3REF: Enable Or Disable A Session Object
10787 ** METHOD: sqlite3_session
10788 **
10789 ** Enable or disable the recording of changes by a session object. When
10790 ** enabled, a session object records changes made to the database. When
10791 ** disabled - it does not. A newly created session object is enabled.
10792 ** Refer to the documentation for [sqlite3session_changeset()] for further
10793 ** details regarding how enabling and disabling a session object affects
10794 ** the eventual changesets.
10795 **
10796 ** Passing zero to this function disables the session. Passing a value
10797 ** greater than zero enables it. Passing a value less than zero is a
10798 ** no-op, and may be used to query the current state of the session.
10799 **
10800 ** The return value indicates the final state of the session object: 0 if
10801 ** the session is disabled, or 1 if it is enabled.
10802 */
10803 SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable);
10804 
10805 /*
10806 ** CAPI3REF: Set Or Clear the Indirect Change Flag
10807 ** METHOD: sqlite3_session
10808 **
10809 ** Each change recorded by a session object is marked as either direct or
10810 ** indirect. A change is marked as indirect if either:
10811 **
10812 ** <ul>
10813 **   <li> The session object "indirect" flag is set when the change is
10814 **        made, or
10815 **   <li> The change is made by an SQL trigger or foreign key action
10816 **        instead of directly as a result of a users SQL statement.
10817 ** </ul>
10818 **
10819 ** If a single row is affected by more than one operation within a session,
10820 ** then the change is considered indirect if all operations meet the criteria
10821 ** for an indirect change above, or direct otherwise.
10822 **
10823 ** This function is used to set, clear or query the session object indirect
10824 ** flag.  If the second argument passed to this function is zero, then the
10825 ** indirect flag is cleared. If it is greater than zero, the indirect flag
10826 ** is set. Passing a value less than zero does not modify the current value
10827 ** of the indirect flag, and may be used to query the current state of the
10828 ** indirect flag for the specified session object.
10829 **
10830 ** The return value indicates the final state of the indirect flag: 0 if
10831 ** it is clear, or 1 if it is set.
10832 */
10833 SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect);
10834 
10835 /*
10836 ** CAPI3REF: Attach A Table To A Session Object
10837 ** METHOD: sqlite3_session
10838 **
10839 ** If argument zTab is not NULL, then it is the name of a table to attach
10840 ** to the session object passed as the first argument. All subsequent changes
10841 ** made to the table while the session object is enabled will be recorded. See
10842 ** documentation for [sqlite3session_changeset()] for further details.
10843 **
10844 ** Or, if argument zTab is NULL, then changes are recorded for all tables
10845 ** in the database. If additional tables are added to the database (by
10846 ** executing "CREATE TABLE" statements) after this call is made, changes for
10847 ** the new tables are also recorded.
10848 **
10849 ** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
10850 ** defined as part of their CREATE TABLE statement. It does not matter if the
10851 ** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
10852 ** KEY may consist of a single column, or may be a composite key.
10853 **
10854 ** It is not an error if the named table does not exist in the database. Nor
10855 ** is it an error if the named table does not have a PRIMARY KEY. However,
10856 ** no changes will be recorded in either of these scenarios.
10857 **
10858 ** Changes are not recorded for individual rows that have NULL values stored
10859 ** in one or more of their PRIMARY KEY columns.
10860 **
10861 ** SQLITE_OK is returned if the call completes without error. Or, if an error
10862 ** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
10863 **
10864 ** <h3>Special sqlite_stat1 Handling</h3>
10865 **
10866 ** As of SQLite version 3.22.0, the "sqlite_stat1" table is an exception to
10867 ** some of the rules above. In SQLite, the schema of sqlite_stat1 is:
10868 **  <pre>
10869 **  &nbsp;     CREATE TABLE sqlite_stat1(tbl,idx,stat)
10870 **  </pre>
10871 **
10872 ** Even though sqlite_stat1 does not have a PRIMARY KEY, changes are
10873 ** recorded for it as if the PRIMARY KEY is (tbl,idx). Additionally, changes
10874 ** are recorded for rows for which (idx IS NULL) is true. However, for such
10875 ** rows a zero-length blob (SQL value X'') is stored in the changeset or
10876 ** patchset instead of a NULL value. This allows such changesets to be
10877 ** manipulated by legacy implementations of sqlite3changeset_invert(),
10878 ** concat() and similar.
10879 **
10880 ** The sqlite3changeset_apply() function automatically converts the
10881 ** zero-length blob back to a NULL value when updating the sqlite_stat1
10882 ** table. However, if the application calls sqlite3changeset_new(),
10883 ** sqlite3changeset_old() or sqlite3changeset_conflict on a changeset
10884 ** iterator directly (including on a changeset iterator passed to a
10885 ** conflict-handler callback) then the X'' value is returned. The application
10886 ** must translate X'' to NULL itself if required.
10887 **
10888 ** Legacy (older than 3.22.0) versions of the sessions module cannot capture
10889 ** changes made to the sqlite_stat1 table. Legacy versions of the
10890 ** sqlite3changeset_apply() function silently ignore any modifications to the
10891 ** sqlite_stat1 table that are part of a changeset or patchset.
10892 */
10893 SQLITE_API int sqlite3session_attach(
10894   sqlite3_session *pSession,      /* Session object */
10895   const char *zTab                /* Table name */
10896 );
10897 
10898 /*
10899 ** CAPI3REF: Set a table filter on a Session Object.
10900 ** METHOD: sqlite3_session
10901 **
10902 ** The second argument (xFilter) is the "filter callback". For changes to rows
10903 ** in tables that are not attached to the Session object, the filter is called
10904 ** to determine whether changes to the table's rows should be tracked or not.
10905 ** If xFilter returns 0, changes are not tracked. Note that once a table is
10906 ** attached, xFilter will not be called again.
10907 */
10908 SQLITE_API void sqlite3session_table_filter(
10909   sqlite3_session *pSession,      /* Session object */
10910   int(*xFilter)(
10911     void *pCtx,                   /* Copy of third arg to _filter_table() */
10912     const char *zTab              /* Table name */
10913   ),
10914   void *pCtx                      /* First argument passed to xFilter */
10915 );
10916 
10917 /*
10918 ** CAPI3REF: Generate A Changeset From A Session Object
10919 ** METHOD: sqlite3_session
10920 **
10921 ** Obtain a changeset containing changes to the tables attached to the
10922 ** session object passed as the first argument. If successful,
10923 ** set *ppChangeset to point to a buffer containing the changeset
10924 ** and *pnChangeset to the size of the changeset in bytes before returning
10925 ** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
10926 ** zero and return an SQLite error code.
10927 **
10928 ** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
10929 ** each representing a change to a single row of an attached table. An INSERT
10930 ** change contains the values of each field of a new database row. A DELETE
10931 ** contains the original values of each field of a deleted database row. An
10932 ** UPDATE change contains the original values of each field of an updated
10933 ** database row along with the updated values for each updated non-primary-key
10934 ** column. It is not possible for an UPDATE change to represent a change that
10935 ** modifies the values of primary key columns. If such a change is made, it
10936 ** is represented in a changeset as a DELETE followed by an INSERT.
10937 **
10938 ** Changes are not recorded for rows that have NULL values stored in one or
10939 ** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
10940 ** no corresponding change is present in the changesets returned by this
10941 ** function. If an existing row with one or more NULL values stored in
10942 ** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
10943 ** only an INSERT is appears in the changeset. Similarly, if an existing row
10944 ** with non-NULL PRIMARY KEY values is updated so that one or more of its
10945 ** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
10946 ** DELETE change only.
10947 **
10948 ** The contents of a changeset may be traversed using an iterator created
10949 ** using the [sqlite3changeset_start()] API. A changeset may be applied to
10950 ** a database with a compatible schema using the [sqlite3changeset_apply()]
10951 ** API.
10952 **
10953 ** Within a changeset generated by this function, all changes related to a
10954 ** single table are grouped together. In other words, when iterating through
10955 ** a changeset or when applying a changeset to a database, all changes related
10956 ** to a single table are processed before moving on to the next table. Tables
10957 ** are sorted in the same order in which they were attached (or auto-attached)
10958 ** to the sqlite3_session object. The order in which the changes related to
10959 ** a single table are stored is undefined.
10960 **
10961 ** Following a successful call to this function, it is the responsibility of
10962 ** the caller to eventually free the buffer that *ppChangeset points to using
10963 ** [sqlite3_free()].
10964 **
10965 ** <h3>Changeset Generation</h3>
10966 **
10967 ** Once a table has been attached to a session object, the session object
10968 ** records the primary key values of all new rows inserted into the table.
10969 ** It also records the original primary key and other column values of any
10970 ** deleted or updated rows. For each unique primary key value, data is only
10971 ** recorded once - the first time a row with said primary key is inserted,
10972 ** updated or deleted in the lifetime of the session.
10973 **
10974 ** There is one exception to the previous paragraph: when a row is inserted,
10975 ** updated or deleted, if one or more of its primary key columns contain a
10976 ** NULL value, no record of the change is made.
10977 **
10978 ** The session object therefore accumulates two types of records - those
10979 ** that consist of primary key values only (created when the user inserts
10980 ** a new record) and those that consist of the primary key values and the
10981 ** original values of other table columns (created when the users deletes
10982 ** or updates a record).
10983 **
10984 ** When this function is called, the requested changeset is created using
10985 ** both the accumulated records and the current contents of the database
10986 ** file. Specifically:
10987 **
10988 ** <ul>
10989 **   <li> For each record generated by an insert, the database is queried
10990 **        for a row with a matching primary key. If one is found, an INSERT
10991 **        change is added to the changeset. If no such row is found, no change
10992 **        is added to the changeset.
10993 **
10994 **   <li> For each record generated by an update or delete, the database is
10995 **        queried for a row with a matching primary key. If such a row is
10996 **        found and one or more of the non-primary key fields have been
10997 **        modified from their original values, an UPDATE change is added to
10998 **        the changeset. Or, if no such row is found in the table, a DELETE
10999 **        change is added to the changeset. If there is a row with a matching
11000 **        primary key in the database, but all fields contain their original
11001 **        values, no change is added to the changeset.
11002 ** </ul>
11003 **
11004 ** This means, amongst other things, that if a row is inserted and then later
11005 ** deleted while a session object is active, neither the insert nor the delete
11006 ** will be present in the changeset. Or if a row is deleted and then later a
11007 ** row with the same primary key values inserted while a session object is
11008 ** active, the resulting changeset will contain an UPDATE change instead of
11009 ** a DELETE and an INSERT.
11010 **
11011 ** When a session object is disabled (see the [sqlite3session_enable()] API),
11012 ** it does not accumulate records when rows are inserted, updated or deleted.
11013 ** This may appear to have some counter-intuitive effects if a single row
11014 ** is written to more than once during a session. For example, if a row
11015 ** is inserted while a session object is enabled, then later deleted while
11016 ** the same session object is disabled, no INSERT record will appear in the
11017 ** changeset, even though the delete took place while the session was disabled.
11018 ** Or, if one field of a row is updated while a session is disabled, and
11019 ** another field of the same row is updated while the session is enabled, the
11020 ** resulting changeset will contain an UPDATE change that updates both fields.
11021 */
11022 SQLITE_API int sqlite3session_changeset(
11023   sqlite3_session *pSession,      /* Session object */
11024   int *pnChangeset,               /* OUT: Size of buffer at *ppChangeset */
11025   void **ppChangeset              /* OUT: Buffer containing changeset */
11026 );
11027 
11028 /*
11029 ** CAPI3REF: Return An Upper-limit For The Size Of The Changeset
11030 ** METHOD: sqlite3_session
11031 **
11032 ** By default, this function always returns 0. For it to return
11033 ** a useful result, the sqlite3_session object must have been configured
11034 ** to enable this API using sqlite3session_object_config() with the
11035 ** SQLITE_SESSION_OBJCONFIG_SIZE verb.
11036 **
11037 ** When enabled, this function returns an upper limit, in bytes, for the size
11038 ** of the changeset that might be produced if sqlite3session_changeset() were
11039 ** called. The final changeset size might be equal to or smaller than the
11040 ** size in bytes returned by this function.
11041 */
11042 SQLITE_API sqlite3_int64 sqlite3session_changeset_size(sqlite3_session *pSession);
11043 
11044 /*
11045 ** CAPI3REF: Load The Difference Between Tables Into A Session
11046 ** METHOD: sqlite3_session
11047 **
11048 ** If it is not already attached to the session object passed as the first
11049 ** argument, this function attaches table zTbl in the same manner as the
11050 ** [sqlite3session_attach()] function. If zTbl does not exist, or if it
11051 ** does not have a primary key, this function is a no-op (but does not return
11052 ** an error).
11053 **
11054 ** Argument zFromDb must be the name of a database ("main", "temp" etc.)
11055 ** attached to the same database handle as the session object that contains
11056 ** a table compatible with the table attached to the session by this function.
11057 ** A table is considered compatible if it:
11058 **
11059 ** <ul>
11060 **   <li> Has the same name,
11061 **   <li> Has the same set of columns declared in the same order, and
11062 **   <li> Has the same PRIMARY KEY definition.
11063 ** </ul>
11064 **
11065 ** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
11066 ** are compatible but do not have any PRIMARY KEY columns, it is not an error
11067 ** but no changes are added to the session object. As with other session
11068 ** APIs, tables without PRIMARY KEYs are simply ignored.
11069 **
11070 ** This function adds a set of changes to the session object that could be
11071 ** used to update the table in database zFrom (call this the "from-table")
11072 ** so that its content is the same as the table attached to the session
11073 ** object (call this the "to-table"). Specifically:
11074 **
11075 ** <ul>
11076 **   <li> For each row (primary key) that exists in the to-table but not in
11077 **     the from-table, an INSERT record is added to the session object.
11078 **
11079 **   <li> For each row (primary key) that exists in the to-table but not in
11080 **     the from-table, a DELETE record is added to the session object.
11081 **
11082 **   <li> For each row (primary key) that exists in both tables, but features
11083 **     different non-PK values in each, an UPDATE record is added to the
11084 **     session.
11085 ** </ul>
11086 **
11087 ** To clarify, if this function is called and then a changeset constructed
11088 ** using [sqlite3session_changeset()], then after applying that changeset to
11089 ** database zFrom the contents of the two compatible tables would be
11090 ** identical.
11091 **
11092 ** It an error if database zFrom does not exist or does not contain the
11093 ** required compatible table.
11094 **
11095 ** If the operation is successful, SQLITE_OK is returned. Otherwise, an SQLite
11096 ** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
11097 ** may be set to point to a buffer containing an English language error
11098 ** message. It is the responsibility of the caller to free this buffer using
11099 ** sqlite3_free().
11100 */
11101 SQLITE_API int sqlite3session_diff(
11102   sqlite3_session *pSession,
11103   const char *zFromDb,
11104   const char *zTbl,
11105   char **pzErrMsg
11106 );
11107 
11108 
11109 /*
11110 ** CAPI3REF: Generate A Patchset From A Session Object
11111 ** METHOD: sqlite3_session
11112 **
11113 ** The differences between a patchset and a changeset are that:
11114 **
11115 ** <ul>
11116 **   <li> DELETE records consist of the primary key fields only. The
11117 **        original values of other fields are omitted.
11118 **   <li> The original values of any modified fields are omitted from
11119 **        UPDATE records.
11120 ** </ul>
11121 **
11122 ** A patchset blob may be used with up to date versions of all
11123 ** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(),
11124 ** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
11125 ** attempting to use a patchset blob with old versions of the
11126 ** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error.
11127 **
11128 ** Because the non-primary key "old.*" fields are omitted, no
11129 ** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
11130 ** is passed to the sqlite3changeset_apply() API. Other conflict types work
11131 ** in the same way as for changesets.
11132 **
11133 ** Changes within a patchset are ordered in the same way as for changesets
11134 ** generated by the sqlite3session_changeset() function (i.e. all changes for
11135 ** a single table are grouped together, tables appear in the order in which
11136 ** they were attached to the session object).
11137 */
11138 SQLITE_API int sqlite3session_patchset(
11139   sqlite3_session *pSession,      /* Session object */
11140   int *pnPatchset,                /* OUT: Size of buffer at *ppPatchset */
11141   void **ppPatchset               /* OUT: Buffer containing patchset */
11142 );
11143 
11144 /*
11145 ** CAPI3REF: Test if a changeset has recorded any changes.
11146 **
11147 ** Return non-zero if no changes to attached tables have been recorded by
11148 ** the session object passed as the first argument. Otherwise, if one or
11149 ** more changes have been recorded, return zero.
11150 **
11151 ** Even if this function returns zero, it is possible that calling
11152 ** [sqlite3session_changeset()] on the session handle may still return a
11153 ** changeset that contains no changes. This can happen when a row in
11154 ** an attached table is modified and then later on the original values
11155 ** are restored. However, if this function returns non-zero, then it is
11156 ** guaranteed that a call to sqlite3session_changeset() will return a
11157 ** changeset containing zero changes.
11158 */
11159 SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);
11160 
11161 /*
11162 ** CAPI3REF: Query for the amount of heap memory used by a session object.
11163 **
11164 ** This API returns the total amount of heap memory in bytes currently
11165 ** used by the session object passed as the only argument.
11166 */
11167 SQLITE_API sqlite3_int64 sqlite3session_memory_used(sqlite3_session *pSession);
11168 
11169 /*
11170 ** CAPI3REF: Create An Iterator To Traverse A Changeset
11171 ** CONSTRUCTOR: sqlite3_changeset_iter
11172 **
11173 ** Create an iterator used to iterate through the contents of a changeset.
11174 ** If successful, *pp is set to point to the iterator handle and SQLITE_OK
11175 ** is returned. Otherwise, if an error occurs, *pp is set to zero and an
11176 ** SQLite error code is returned.
11177 **
11178 ** The following functions can be used to advance and query a changeset
11179 ** iterator created by this function:
11180 **
11181 ** <ul>
11182 **   <li> [sqlite3changeset_next()]
11183 **   <li> [sqlite3changeset_op()]
11184 **   <li> [sqlite3changeset_new()]
11185 **   <li> [sqlite3changeset_old()]
11186 ** </ul>
11187 **
11188 ** It is the responsibility of the caller to eventually destroy the iterator
11189 ** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
11190 ** changeset (pChangeset) must remain valid until after the iterator is
11191 ** destroyed.
11192 **
11193 ** Assuming the changeset blob was created by one of the
11194 ** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
11195 ** [sqlite3changeset_invert()] functions, all changes within the changeset
11196 ** that apply to a single table are grouped together. This means that when
11197 ** an application iterates through a changeset using an iterator created by
11198 ** this function, all changes that relate to a single table are visited
11199 ** consecutively. There is no chance that the iterator will visit a change
11200 ** the applies to table X, then one for table Y, and then later on visit
11201 ** another change for table X.
11202 **
11203 ** The behavior of sqlite3changeset_start_v2() and its streaming equivalent
11204 ** may be modified by passing a combination of
11205 ** [SQLITE_CHANGESETSTART_INVERT | supported flags] as the 4th parameter.
11206 **
11207 ** Note that the sqlite3changeset_start_v2() API is still <b>experimental</b>
11208 ** and therefore subject to change.
11209 */
11210 SQLITE_API int sqlite3changeset_start(
11211   sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
11212   int nChangeset,                 /* Size of changeset blob in bytes */
11213   void *pChangeset                /* Pointer to blob containing changeset */
11214 );
11215 SQLITE_API int sqlite3changeset_start_v2(
11216   sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
11217   int nChangeset,                 /* Size of changeset blob in bytes */
11218   void *pChangeset,               /* Pointer to blob containing changeset */
11219   int flags                       /* SESSION_CHANGESETSTART_* flags */
11220 );
11221 
11222 /*
11223 ** CAPI3REF: Flags for sqlite3changeset_start_v2
11224 **
11225 ** The following flags may passed via the 4th parameter to
11226 ** [sqlite3changeset_start_v2] and [sqlite3changeset_start_v2_strm]:
11227 **
11228 ** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
11229 **   Invert the changeset while iterating through it. This is equivalent to
11230 **   inverting a changeset using sqlite3changeset_invert() before applying it.
11231 **   It is an error to specify this flag with a patchset.
11232 */
11233 #define SQLITE_CHANGESETSTART_INVERT        0x0002
11234 
11235 
11236 /*
11237 ** CAPI3REF: Advance A Changeset Iterator
11238 ** METHOD: sqlite3_changeset_iter
11239 **
11240 ** This function may only be used with iterators created by the function
11241 ** [sqlite3changeset_start()]. If it is called on an iterator passed to
11242 ** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
11243 ** is returned and the call has no effect.
11244 **
11245 ** Immediately after an iterator is created by sqlite3changeset_start(), it
11246 ** does not point to any change in the changeset. Assuming the changeset
11247 ** is not empty, the first call to this function advances the iterator to
11248 ** point to the first change in the changeset. Each subsequent call advances
11249 ** the iterator to point to the next change in the changeset (if any). If
11250 ** no error occurs and the iterator points to a valid change after a call
11251 ** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned.
11252 ** Otherwise, if all changes in the changeset have already been visited,
11253 ** SQLITE_DONE is returned.
11254 **
11255 ** If an error occurs, an SQLite error code is returned. Possible error
11256 ** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or
11257 ** SQLITE_NOMEM.
11258 */
11259 SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *pIter);
11260 
11261 /*
11262 ** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
11263 ** METHOD: sqlite3_changeset_iter
11264 **
11265 ** The pIter argument passed to this function may either be an iterator
11266 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
11267 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
11268 ** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
11269 ** is not the case, this function returns [SQLITE_MISUSE].
11270 **
11271 ** Arguments pOp, pnCol and pzTab may not be NULL. Upon return, three
11272 ** outputs are set through these pointers:
11273 **
11274 ** *pOp is set to one of [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE],
11275 ** depending on the type of change that the iterator currently points to;
11276 **
11277 ** *pnCol is set to the number of columns in the table affected by the change; and
11278 **
11279 ** *pzTab is set to point to a nul-terminated utf-8 encoded string containing
11280 ** the name of the table affected by the current change. The buffer remains
11281 ** valid until either sqlite3changeset_next() is called on the iterator
11282 ** or until the conflict-handler function returns.
11283 **
11284 ** If pbIndirect is not NULL, then *pbIndirect is set to true (1) if the change
11285 ** is an indirect change, or false (0) otherwise. See the documentation for
11286 ** [sqlite3session_indirect()] for a description of direct and indirect
11287 ** changes.
11288 **
11289 ** If no error occurs, SQLITE_OK is returned. If an error does occur, an
11290 ** SQLite error code is returned. The values of the output variables may not
11291 ** be trusted in this case.
11292 */
11293 SQLITE_API int sqlite3changeset_op(
11294   sqlite3_changeset_iter *pIter,  /* Iterator object */
11295   const char **pzTab,             /* OUT: Pointer to table name */
11296   int *pnCol,                     /* OUT: Number of columns in table */
11297   int *pOp,                       /* OUT: SQLITE_INSERT, DELETE or UPDATE */
11298   int *pbIndirect                 /* OUT: True for an 'indirect' change */
11299 );
11300 
11301 /*
11302 ** CAPI3REF: Obtain The Primary Key Definition Of A Table
11303 ** METHOD: sqlite3_changeset_iter
11304 **
11305 ** For each modified table, a changeset includes the following:
11306 **
11307 ** <ul>
11308 **   <li> The number of columns in the table, and
11309 **   <li> Which of those columns make up the tables PRIMARY KEY.
11310 ** </ul>
11311 **
11312 ** This function is used to find which columns comprise the PRIMARY KEY of
11313 ** the table modified by the change that iterator pIter currently points to.
11314 ** If successful, *pabPK is set to point to an array of nCol entries, where
11315 ** nCol is the number of columns in the table. Elements of *pabPK are set to
11316 ** 0x01 if the corresponding column is part of the tables primary key, or
11317 ** 0x00 if it is not.
11318 **
11319 ** If argument pnCol is not NULL, then *pnCol is set to the number of columns
11320 ** in the table.
11321 **
11322 ** If this function is called when the iterator does not point to a valid
11323 ** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
11324 ** SQLITE_OK is returned and the output variables populated as described
11325 ** above.
11326 */
11327 SQLITE_API int sqlite3changeset_pk(
11328   sqlite3_changeset_iter *pIter,  /* Iterator object */
11329   unsigned char **pabPK,          /* OUT: Array of boolean - true for PK cols */
11330   int *pnCol                      /* OUT: Number of entries in output array */
11331 );
11332 
11333 /*
11334 ** CAPI3REF: Obtain old.* Values From A Changeset Iterator
11335 ** METHOD: sqlite3_changeset_iter
11336 **
11337 ** The pIter argument passed to this function may either be an iterator
11338 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
11339 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
11340 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
11341 ** Furthermore, it may only be called if the type of change that the iterator
11342 ** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
11343 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
11344 **
11345 ** Argument iVal must be greater than or equal to 0, and less than the number
11346 ** of columns in the table affected by the current change. Otherwise,
11347 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
11348 **
11349 ** If successful, this function sets *ppValue to point to a protected
11350 ** sqlite3_value object containing the iVal'th value from the vector of
11351 ** original row values stored as part of the UPDATE or DELETE change and
11352 ** returns SQLITE_OK. The name of the function comes from the fact that this
11353 ** is similar to the "old.*" columns available to update or delete triggers.
11354 **
11355 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
11356 ** is returned and *ppValue is set to NULL.
11357 */
11358 SQLITE_API int sqlite3changeset_old(
11359   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
11360   int iVal,                       /* Column number */
11361   sqlite3_value **ppValue         /* OUT: Old value (or NULL pointer) */
11362 );
11363 
11364 /*
11365 ** CAPI3REF: Obtain new.* Values From A Changeset Iterator
11366 ** METHOD: sqlite3_changeset_iter
11367 **
11368 ** The pIter argument passed to this function may either be an iterator
11369 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
11370 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
11371 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
11372 ** Furthermore, it may only be called if the type of change that the iterator
11373 ** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
11374 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
11375 **
11376 ** Argument iVal must be greater than or equal to 0, and less than the number
11377 ** of columns in the table affected by the current change. Otherwise,
11378 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
11379 **
11380 ** If successful, this function sets *ppValue to point to a protected
11381 ** sqlite3_value object containing the iVal'th value from the vector of
11382 ** new row values stored as part of the UPDATE or INSERT change and
11383 ** returns SQLITE_OK. If the change is an UPDATE and does not include
11384 ** a new value for the requested column, *ppValue is set to NULL and
11385 ** SQLITE_OK returned. The name of the function comes from the fact that
11386 ** this is similar to the "new.*" columns available to update or delete
11387 ** triggers.
11388 **
11389 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
11390 ** is returned and *ppValue is set to NULL.
11391 */
11392 SQLITE_API int sqlite3changeset_new(
11393   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
11394   int iVal,                       /* Column number */
11395   sqlite3_value **ppValue         /* OUT: New value (or NULL pointer) */
11396 );
11397 
11398 /*
11399 ** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
11400 ** METHOD: sqlite3_changeset_iter
11401 **
11402 ** This function should only be used with iterator objects passed to a
11403 ** conflict-handler callback by [sqlite3changeset_apply()] with either
11404 ** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
11405 ** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
11406 ** is set to NULL.
11407 **
11408 ** Argument iVal must be greater than or equal to 0, and less than the number
11409 ** of columns in the table affected by the current change. Otherwise,
11410 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
11411 **
11412 ** If successful, this function sets *ppValue to point to a protected
11413 ** sqlite3_value object containing the iVal'th value from the
11414 ** "conflicting row" associated with the current conflict-handler callback
11415 ** and returns SQLITE_OK.
11416 **
11417 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
11418 ** is returned and *ppValue is set to NULL.
11419 */
11420 SQLITE_API int sqlite3changeset_conflict(
11421   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
11422   int iVal,                       /* Column number */
11423   sqlite3_value **ppValue         /* OUT: Value from conflicting row */
11424 );
11425 
11426 /*
11427 ** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
11428 ** METHOD: sqlite3_changeset_iter
11429 **
11430 ** This function may only be called with an iterator passed to an
11431 ** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
11432 ** it sets the output variable to the total number of known foreign key
11433 ** violations in the destination database and returns SQLITE_OK.
11434 **
11435 ** In all other cases this function returns SQLITE_MISUSE.
11436 */
11437 SQLITE_API int sqlite3changeset_fk_conflicts(
11438   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
11439   int *pnOut                      /* OUT: Number of FK violations */
11440 );
11441 
11442 
11443 /*
11444 ** CAPI3REF: Finalize A Changeset Iterator
11445 ** METHOD: sqlite3_changeset_iter
11446 **
11447 ** This function is used to finalize an iterator allocated with
11448 ** [sqlite3changeset_start()].
11449 **
11450 ** This function should only be called on iterators created using the
11451 ** [sqlite3changeset_start()] function. If an application calls this
11452 ** function with an iterator passed to a conflict-handler by
11453 ** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
11454 ** call has no effect.
11455 **
11456 ** If an error was encountered within a call to an sqlite3changeset_xxx()
11457 ** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an
11458 ** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
11459 ** to that error is returned by this function. Otherwise, SQLITE_OK is
11460 ** returned. This is to allow the following pattern (pseudo-code):
11461 **
11462 ** <pre>
11463 **   sqlite3changeset_start();
11464 **   while( SQLITE_ROW==sqlite3changeset_next() ){
11465 **     // Do something with change.
11466 **   }
11467 **   rc = sqlite3changeset_finalize();
11468 **   if( rc!=SQLITE_OK ){
11469 **     // An error has occurred
11470 **   }
11471 ** </pre>
11472 */
11473 SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);
11474 
11475 /*
11476 ** CAPI3REF: Invert A Changeset
11477 **
11478 ** This function is used to "invert" a changeset object. Applying an inverted
11479 ** changeset to a database reverses the effects of applying the uninverted
11480 ** changeset. Specifically:
11481 **
11482 ** <ul>
11483 **   <li> Each DELETE change is changed to an INSERT, and
11484 **   <li> Each INSERT change is changed to a DELETE, and
11485 **   <li> For each UPDATE change, the old.* and new.* values are exchanged.
11486 ** </ul>
11487 **
11488 ** This function does not change the order in which changes appear within
11489 ** the changeset. It merely reverses the sense of each individual change.
11490 **
11491 ** If successful, a pointer to a buffer containing the inverted changeset
11492 ** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
11493 ** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
11494 ** zeroed and an SQLite error code returned.
11495 **
11496 ** It is the responsibility of the caller to eventually call sqlite3_free()
11497 ** on the *ppOut pointer to free the buffer allocation following a successful
11498 ** call to this function.
11499 **
11500 ** WARNING/TODO: This function currently assumes that the input is a valid
11501 ** changeset. If it is not, the results are undefined.
11502 */
11503 SQLITE_API int sqlite3changeset_invert(
11504   int nIn, const void *pIn,       /* Input changeset */
11505   int *pnOut, void **ppOut        /* OUT: Inverse of input */
11506 );
11507 
11508 /*
11509 ** CAPI3REF: Concatenate Two Changeset Objects
11510 **
11511 ** This function is used to concatenate two changesets, A and B, into a
11512 ** single changeset. The result is a changeset equivalent to applying
11513 ** changeset A followed by changeset B.
11514 **
11515 ** This function combines the two input changesets using an
11516 ** sqlite3_changegroup object. Calling it produces similar results as the
11517 ** following code fragment:
11518 **
11519 ** <pre>
11520 **   sqlite3_changegroup *pGrp;
11521 **   rc = sqlite3_changegroup_new(&pGrp);
11522 **   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
11523 **   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
11524 **   if( rc==SQLITE_OK ){
11525 **     rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
11526 **   }else{
11527 **     *ppOut = 0;
11528 **     *pnOut = 0;
11529 **   }
11530 ** </pre>
11531 **
11532 ** Refer to the sqlite3_changegroup documentation below for details.
11533 */
11534 SQLITE_API int sqlite3changeset_concat(
11535   int nA,                         /* Number of bytes in buffer pA */
11536   void *pA,                       /* Pointer to buffer containing changeset A */
11537   int nB,                         /* Number of bytes in buffer pB */
11538   void *pB,                       /* Pointer to buffer containing changeset B */
11539   int *pnOut,                     /* OUT: Number of bytes in output changeset */
11540   void **ppOut                    /* OUT: Buffer containing output changeset */
11541 );
11542 
11543 
11544 /*
11545 ** CAPI3REF: Changegroup Handle
11546 **
11547 ** A changegroup is an object used to combine two or more
11548 ** [changesets] or [patchsets]
11549 */
11550 typedef struct sqlite3_changegroup sqlite3_changegroup;
11551 
11552 /*
11553 ** CAPI3REF: Create A New Changegroup Object
11554 ** CONSTRUCTOR: sqlite3_changegroup
11555 **
11556 ** An sqlite3_changegroup object is used to combine two or more changesets
11557 ** (or patchsets) into a single changeset (or patchset). A single changegroup
11558 ** object may combine changesets or patchsets, but not both. The output is
11559 ** always in the same format as the input.
11560 **
11561 ** If successful, this function returns SQLITE_OK and populates (*pp) with
11562 ** a pointer to a new sqlite3_changegroup object before returning. The caller
11563 ** should eventually free the returned object using a call to
11564 ** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
11565 ** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
11566 **
11567 ** The usual usage pattern for an sqlite3_changegroup object is as follows:
11568 **
11569 ** <ul>
11570 **   <li> It is created using a call to sqlite3changegroup_new().
11571 **
11572 **   <li> Zero or more changesets (or patchsets) are added to the object
11573 **        by calling sqlite3changegroup_add().
11574 **
11575 **   <li> The result of combining all input changesets together is obtained
11576 **        by the application via a call to sqlite3changegroup_output().
11577 **
11578 **   <li> The object is deleted using a call to sqlite3changegroup_delete().
11579 ** </ul>
11580 **
11581 ** Any number of calls to add() and output() may be made between the calls to
11582 ** new() and delete(), and in any order.
11583 **
11584 ** As well as the regular sqlite3changegroup_add() and
11585 ** sqlite3changegroup_output() functions, also available are the streaming
11586 ** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
11587 */
11588 SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp);
11589 
11590 /*
11591 ** CAPI3REF: Add A Changeset To A Changegroup
11592 ** METHOD: sqlite3_changegroup
11593 **
11594 ** Add all changes within the changeset (or patchset) in buffer pData (size
11595 ** nData bytes) to the changegroup.
11596 **
11597 ** If the buffer contains a patchset, then all prior calls to this function
11598 ** on the same changegroup object must also have specified patchsets. Or, if
11599 ** the buffer contains a changeset, so must have the earlier calls to this
11600 ** function. Otherwise, SQLITE_ERROR is returned and no changes are added
11601 ** to the changegroup.
11602 **
11603 ** Rows within the changeset and changegroup are identified by the values in
11604 ** their PRIMARY KEY columns. A change in the changeset is considered to
11605 ** apply to the same row as a change already present in the changegroup if
11606 ** the two rows have the same primary key.
11607 **
11608 ** Changes to rows that do not already appear in the changegroup are
11609 ** simply copied into it. Or, if both the new changeset and the changegroup
11610 ** contain changes that apply to a single row, the final contents of the
11611 ** changegroup depends on the type of each change, as follows:
11612 **
11613 ** <table border=1 style="margin-left:8ex;margin-right:8ex">
11614 **   <tr><th style="white-space:pre">Existing Change  </th>
11615 **       <th style="white-space:pre">New Change       </th>
11616 **       <th>Output Change
11617 **   <tr><td>INSERT <td>INSERT <td>
11618 **       The new change is ignored. This case does not occur if the new
11619 **       changeset was recorded immediately after the changesets already
11620 **       added to the changegroup.
11621 **   <tr><td>INSERT <td>UPDATE <td>
11622 **       The INSERT change remains in the changegroup. The values in the
11623 **       INSERT change are modified as if the row was inserted by the
11624 **       existing change and then updated according to the new change.
11625 **   <tr><td>INSERT <td>DELETE <td>
11626 **       The existing INSERT is removed from the changegroup. The DELETE is
11627 **       not added.
11628 **   <tr><td>UPDATE <td>INSERT <td>
11629 **       The new change is ignored. This case does not occur if the new
11630 **       changeset was recorded immediately after the changesets already
11631 **       added to the changegroup.
11632 **   <tr><td>UPDATE <td>UPDATE <td>
11633 **       The existing UPDATE remains within the changegroup. It is amended
11634 **       so that the accompanying values are as if the row was updated once
11635 **       by the existing change and then again by the new change.
11636 **   <tr><td>UPDATE <td>DELETE <td>
11637 **       The existing UPDATE is replaced by the new DELETE within the
11638 **       changegroup.
11639 **   <tr><td>DELETE <td>INSERT <td>
11640 **       If one or more of the column values in the row inserted by the
11641 **       new change differ from those in the row deleted by the existing
11642 **       change, the existing DELETE is replaced by an UPDATE within the
11643 **       changegroup. Otherwise, if the inserted row is exactly the same
11644 **       as the deleted row, the existing DELETE is simply discarded.
11645 **   <tr><td>DELETE <td>UPDATE <td>
11646 **       The new change is ignored. This case does not occur if the new
11647 **       changeset was recorded immediately after the changesets already
11648 **       added to the changegroup.
11649 **   <tr><td>DELETE <td>DELETE <td>
11650 **       The new change is ignored. This case does not occur if the new
11651 **       changeset was recorded immediately after the changesets already
11652 **       added to the changegroup.
11653 ** </table>
11654 **
11655 ** If the new changeset contains changes to a table that is already present
11656 ** in the changegroup, then the number of columns and the position of the
11657 ** primary key columns for the table must be consistent. If this is not the
11658 ** case, this function fails with SQLITE_SCHEMA. If the input changeset
11659 ** appears to be corrupt and the corruption is detected, SQLITE_CORRUPT is
11660 ** returned. Or, if an out-of-memory condition occurs during processing, this
11661 ** function returns SQLITE_NOMEM. In all cases, if an error occurs the state
11662 ** of the final contents of the changegroup is undefined.
11663 **
11664 ** If no error occurs, SQLITE_OK is returned.
11665 */
11666 SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData);
11667 
11668 /*
11669 ** CAPI3REF: Obtain A Composite Changeset From A Changegroup
11670 ** METHOD: sqlite3_changegroup
11671 **
11672 ** Obtain a buffer containing a changeset (or patchset) representing the
11673 ** current contents of the changegroup. If the inputs to the changegroup
11674 ** were themselves changesets, the output is a changeset. Or, if the
11675 ** inputs were patchsets, the output is also a patchset.
11676 **
11677 ** As with the output of the sqlite3session_changeset() and
11678 ** sqlite3session_patchset() functions, all changes related to a single
11679 ** table are grouped together in the output of this function. Tables appear
11680 ** in the same order as for the very first changeset added to the changegroup.
11681 ** If the second or subsequent changesets added to the changegroup contain
11682 ** changes for tables that do not appear in the first changeset, they are
11683 ** appended onto the end of the output changeset, again in the order in
11684 ** which they are first encountered.
11685 **
11686 ** If an error occurs, an SQLite error code is returned and the output
11687 ** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
11688 ** is returned and the output variables are set to the size of and a
11689 ** pointer to the output buffer, respectively. In this case it is the
11690 ** responsibility of the caller to eventually free the buffer using a
11691 ** call to sqlite3_free().
11692 */
11693 SQLITE_API int sqlite3changegroup_output(
11694   sqlite3_changegroup*,
11695   int *pnData,                    /* OUT: Size of output buffer in bytes */
11696   void **ppData                   /* OUT: Pointer to output buffer */
11697 );
11698 
11699 /*
11700 ** CAPI3REF: Delete A Changegroup Object
11701 ** DESTRUCTOR: sqlite3_changegroup
11702 */
11703 SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup*);
11704 
11705 /*
11706 ** CAPI3REF: Apply A Changeset To A Database
11707 **
11708 ** Apply a changeset or patchset to a database. These functions attempt to
11709 ** update the "main" database attached to handle db with the changes found in
11710 ** the changeset passed via the second and third arguments.
11711 **
11712 ** The fourth argument (xFilter) passed to these functions is the "filter
11713 ** callback". If it is not NULL, then for each table affected by at least one
11714 ** change in the changeset, the filter callback is invoked with
11715 ** the table name as the second argument, and a copy of the context pointer
11716 ** passed as the sixth argument as the first. If the "filter callback"
11717 ** returns zero, then no attempt is made to apply any changes to the table.
11718 ** Otherwise, if the return value is non-zero or the xFilter argument to
11719 ** is NULL, all changes related to the table are attempted.
11720 **
11721 ** For each table that is not excluded by the filter callback, this function
11722 ** tests that the target database contains a compatible table. A table is
11723 ** considered compatible if all of the following are true:
11724 **
11725 ** <ul>
11726 **   <li> The table has the same name as the name recorded in the
11727 **        changeset, and
11728 **   <li> The table has at least as many columns as recorded in the
11729 **        changeset, and
11730 **   <li> The table has primary key columns in the same position as
11731 **        recorded in the changeset.
11732 ** </ul>
11733 **
11734 ** If there is no compatible table, it is not an error, but none of the
11735 ** changes associated with the table are applied. A warning message is issued
11736 ** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
11737 ** one such warning is issued for each table in the changeset.
11738 **
11739 ** For each change for which there is a compatible table, an attempt is made
11740 ** to modify the table contents according to the UPDATE, INSERT or DELETE
11741 ** change. If a change cannot be applied cleanly, the conflict handler
11742 ** function passed as the fifth argument to sqlite3changeset_apply() may be
11743 ** invoked. A description of exactly when the conflict handler is invoked for
11744 ** each type of change is below.
11745 **
11746 ** Unlike the xFilter argument, xConflict may not be passed NULL. The results
11747 ** of passing anything other than a valid function pointer as the xConflict
11748 ** argument are undefined.
11749 **
11750 ** Each time the conflict handler function is invoked, it must return one
11751 ** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or
11752 ** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
11753 ** if the second argument passed to the conflict handler is either
11754 ** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
11755 ** returns an illegal value, any changes already made are rolled back and
11756 ** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different
11757 ** actions are taken by sqlite3changeset_apply() depending on the value
11758 ** returned by each invocation of the conflict-handler function. Refer to
11759 ** the documentation for the three
11760 ** [SQLITE_CHANGESET_OMIT|available return values] for details.
11761 **
11762 ** <dl>
11763 ** <dt>DELETE Changes<dd>
11764 **   For each DELETE change, the function checks if the target database
11765 **   contains a row with the same primary key value (or values) as the
11766 **   original row values stored in the changeset. If it does, and the values
11767 **   stored in all non-primary key columns also match the values stored in
11768 **   the changeset the row is deleted from the target database.
11769 **
11770 **   If a row with matching primary key values is found, but one or more of
11771 **   the non-primary key fields contains a value different from the original
11772 **   row value stored in the changeset, the conflict-handler function is
11773 **   invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the
11774 **   database table has more columns than are recorded in the changeset,
11775 **   only the values of those non-primary key fields are compared against
11776 **   the current database contents - any trailing database table columns
11777 **   are ignored.
11778 **
11779 **   If no row with matching primary key values is found in the database,
11780 **   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
11781 **   passed as the second argument.
11782 **
11783 **   If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
11784 **   (which can only happen if a foreign key constraint is violated), the
11785 **   conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
11786 **   passed as the second argument. This includes the case where the DELETE
11787 **   operation is attempted because an earlier call to the conflict handler
11788 **   function returned [SQLITE_CHANGESET_REPLACE].
11789 **
11790 ** <dt>INSERT Changes<dd>
11791 **   For each INSERT change, an attempt is made to insert the new row into
11792 **   the database. If the changeset row contains fewer fields than the
11793 **   database table, the trailing fields are populated with their default
11794 **   values.
11795 **
11796 **   If the attempt to insert the row fails because the database already
11797 **   contains a row with the same primary key values, the conflict handler
11798 **   function is invoked with the second argument set to
11799 **   [SQLITE_CHANGESET_CONFLICT].
11800 **
11801 **   If the attempt to insert the row fails because of some other constraint
11802 **   violation (e.g. NOT NULL or UNIQUE), the conflict handler function is
11803 **   invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
11804 **   This includes the case where the INSERT operation is re-attempted because
11805 **   an earlier call to the conflict handler function returned
11806 **   [SQLITE_CHANGESET_REPLACE].
11807 **
11808 ** <dt>UPDATE Changes<dd>
11809 **   For each UPDATE change, the function checks if the target database
11810 **   contains a row with the same primary key value (or values) as the
11811 **   original row values stored in the changeset. If it does, and the values
11812 **   stored in all modified non-primary key columns also match the values
11813 **   stored in the changeset the row is updated within the target database.
11814 **
11815 **   If a row with matching primary key values is found, but one or more of
11816 **   the modified non-primary key fields contains a value different from an
11817 **   original row value stored in the changeset, the conflict-handler function
11818 **   is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
11819 **   UPDATE changes only contain values for non-primary key fields that are
11820 **   to be modified, only those fields need to match the original values to
11821 **   avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
11822 **
11823 **   If no row with matching primary key values is found in the database,
11824 **   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
11825 **   passed as the second argument.
11826 **
11827 **   If the UPDATE operation is attempted, but SQLite returns
11828 **   SQLITE_CONSTRAINT, the conflict-handler function is invoked with
11829 **   [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
11830 **   This includes the case where the UPDATE operation is attempted after
11831 **   an earlier call to the conflict handler function returned
11832 **   [SQLITE_CHANGESET_REPLACE].
11833 ** </dl>
11834 **
11835 ** It is safe to execute SQL statements, including those that write to the
11836 ** table that the callback related to, from within the xConflict callback.
11837 ** This can be used to further customize the application's conflict
11838 ** resolution strategy.
11839 **
11840 ** All changes made by these functions are enclosed in a savepoint transaction.
11841 ** If any other error (aside from a constraint failure when attempting to
11842 ** write to the target database) occurs, then the savepoint transaction is
11843 ** rolled back, restoring the target database to its original state, and an
11844 ** SQLite error code returned.
11845 **
11846 ** If the output parameters (ppRebase) and (pnRebase) are non-NULL and
11847 ** the input is a changeset (not a patchset), then sqlite3changeset_apply_v2()
11848 ** may set (*ppRebase) to point to a "rebase" that may be used with the
11849 ** sqlite3_rebaser APIs buffer before returning. In this case (*pnRebase)
11850 ** is set to the size of the buffer in bytes. It is the responsibility of the
11851 ** caller to eventually free any such buffer using sqlite3_free(). The buffer
11852 ** is only allocated and populated if one or more conflicts were encountered
11853 ** while applying the patchset. See comments surrounding the sqlite3_rebaser
11854 ** APIs for further details.
11855 **
11856 ** The behavior of sqlite3changeset_apply_v2() and its streaming equivalent
11857 ** may be modified by passing a combination of
11858 ** [SQLITE_CHANGESETAPPLY_NOSAVEPOINT | supported flags] as the 9th parameter.
11859 **
11860 ** Note that the sqlite3changeset_apply_v2() API is still <b>experimental</b>
11861 ** and therefore subject to change.
11862 */
11863 SQLITE_API int sqlite3changeset_apply(
11864   sqlite3 *db,                    /* Apply change to "main" db of this handle */
11865   int nChangeset,                 /* Size of changeset in bytes */
11866   void *pChangeset,               /* Changeset blob */
11867   int(*xFilter)(
11868     void *pCtx,                   /* Copy of sixth arg to _apply() */
11869     const char *zTab              /* Table name */
11870   ),
11871   int(*xConflict)(
11872     void *pCtx,                   /* Copy of sixth arg to _apply() */
11873     int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
11874     sqlite3_changeset_iter *p     /* Handle describing change and conflict */
11875   ),
11876   void *pCtx                      /* First argument passed to xConflict */
11877 );
11878 SQLITE_API int sqlite3changeset_apply_v2(
11879   sqlite3 *db,                    /* Apply change to "main" db of this handle */
11880   int nChangeset,                 /* Size of changeset in bytes */
11881   void *pChangeset,               /* Changeset blob */
11882   int(*xFilter)(
11883     void *pCtx,                   /* Copy of sixth arg to _apply() */
11884     const char *zTab              /* Table name */
11885   ),
11886   int(*xConflict)(
11887     void *pCtx,                   /* Copy of sixth arg to _apply() */
11888     int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
11889     sqlite3_changeset_iter *p     /* Handle describing change and conflict */
11890   ),
11891   void *pCtx,                     /* First argument passed to xConflict */
11892   void **ppRebase, int *pnRebase, /* OUT: Rebase data */
11893   int flags                       /* SESSION_CHANGESETAPPLY_* flags */
11894 );
11895 
11896 /*
11897 ** CAPI3REF: Flags for sqlite3changeset_apply_v2
11898 **
11899 ** The following flags may passed via the 9th parameter to
11900 ** [sqlite3changeset_apply_v2] and [sqlite3changeset_apply_v2_strm]:
11901 **
11902 ** <dl>
11903 ** <dt>SQLITE_CHANGESETAPPLY_NOSAVEPOINT <dd>
11904 **   Usually, the sessions module encloses all operations performed by
11905 **   a single call to apply_v2() or apply_v2_strm() in a [SAVEPOINT]. The
11906 **   SAVEPOINT is committed if the changeset or patchset is successfully
11907 **   applied, or rolled back if an error occurs. Specifying this flag
11908 **   causes the sessions module to omit this savepoint. In this case, if the
11909 **   caller has an open transaction or savepoint when apply_v2() is called,
11910 **   it may revert the partially applied changeset by rolling it back.
11911 **
11912 ** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
11913 **   Invert the changeset before applying it. This is equivalent to inverting
11914 **   a changeset using sqlite3changeset_invert() before applying it. It is
11915 **   an error to specify this flag with a patchset.
11916 */
11917 #define SQLITE_CHANGESETAPPLY_NOSAVEPOINT   0x0001
11918 #define SQLITE_CHANGESETAPPLY_INVERT        0x0002
11919 
11920 /*
11921 ** CAPI3REF: Constants Passed To The Conflict Handler
11922 **
11923 ** Values that may be passed as the second argument to a conflict-handler.
11924 **
11925 ** <dl>
11926 ** <dt>SQLITE_CHANGESET_DATA<dd>
11927 **   The conflict handler is invoked with CHANGESET_DATA as the second argument
11928 **   when processing a DELETE or UPDATE change if a row with the required
11929 **   PRIMARY KEY fields is present in the database, but one or more other
11930 **   (non primary-key) fields modified by the update do not contain the
11931 **   expected "before" values.
11932 **
11933 **   The conflicting row, in this case, is the database row with the matching
11934 **   primary key.
11935 **
11936 ** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
11937 **   The conflict handler is invoked with CHANGESET_NOTFOUND as the second
11938 **   argument when processing a DELETE or UPDATE change if a row with the
11939 **   required PRIMARY KEY fields is not present in the database.
11940 **
11941 **   There is no conflicting row in this case. The results of invoking the
11942 **   sqlite3changeset_conflict() API are undefined.
11943 **
11944 ** <dt>SQLITE_CHANGESET_CONFLICT<dd>
11945 **   CHANGESET_CONFLICT is passed as the second argument to the conflict
11946 **   handler while processing an INSERT change if the operation would result
11947 **   in duplicate primary key values.
11948 **
11949 **   The conflicting row in this case is the database row with the matching
11950 **   primary key.
11951 **
11952 ** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
11953 **   If foreign key handling is enabled, and applying a changeset leaves the
11954 **   database in a state containing foreign key violations, the conflict
11955 **   handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
11956 **   exactly once before the changeset is committed. If the conflict handler
11957 **   returns CHANGESET_OMIT, the changes, including those that caused the
11958 **   foreign key constraint violation, are committed. Or, if it returns
11959 **   CHANGESET_ABORT, the changeset is rolled back.
11960 **
11961 **   No current or conflicting row information is provided. The only function
11962 **   it is possible to call on the supplied sqlite3_changeset_iter handle
11963 **   is sqlite3changeset_fk_conflicts().
11964 **
11965 ** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
11966 **   If any other constraint violation occurs while applying a change (i.e.
11967 **   a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is
11968 **   invoked with CHANGESET_CONSTRAINT as the second argument.
11969 **
11970 **   There is no conflicting row in this case. The results of invoking the
11971 **   sqlite3changeset_conflict() API are undefined.
11972 **
11973 ** </dl>
11974 */
11975 #define SQLITE_CHANGESET_DATA        1
11976 #define SQLITE_CHANGESET_NOTFOUND    2
11977 #define SQLITE_CHANGESET_CONFLICT    3
11978 #define SQLITE_CHANGESET_CONSTRAINT  4
11979 #define SQLITE_CHANGESET_FOREIGN_KEY 5
11980 
11981 /*
11982 ** CAPI3REF: Constants Returned By The Conflict Handler
11983 **
11984 ** A conflict handler callback must return one of the following three values.
11985 **
11986 ** <dl>
11987 ** <dt>SQLITE_CHANGESET_OMIT<dd>
11988 **   If a conflict handler returns this value no special action is taken. The
11989 **   change that caused the conflict is not applied. The session module
11990 **   continues to the next change in the changeset.
11991 **
11992 ** <dt>SQLITE_CHANGESET_REPLACE<dd>
11993 **   This value may only be returned if the second argument to the conflict
11994 **   handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
11995 **   is not the case, any changes applied so far are rolled back and the
11996 **   call to sqlite3changeset_apply() returns SQLITE_MISUSE.
11997 **
11998 **   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
11999 **   handler, then the conflicting row is either updated or deleted, depending
12000 **   on the type of change.
12001 **
12002 **   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
12003 **   handler, then the conflicting row is removed from the database and a
12004 **   second attempt to apply the change is made. If this second attempt fails,
12005 **   the original row is restored to the database before continuing.
12006 **
12007 ** <dt>SQLITE_CHANGESET_ABORT<dd>
12008 **   If this value is returned, any changes applied so far are rolled back
12009 **   and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
12010 ** </dl>
12011 */
12012 #define SQLITE_CHANGESET_OMIT       0
12013 #define SQLITE_CHANGESET_REPLACE    1
12014 #define SQLITE_CHANGESET_ABORT      2
12015 
12016 /*
12017 ** CAPI3REF: Rebasing changesets
12018 ** EXPERIMENTAL
12019 **
12020 ** Suppose there is a site hosting a database in state S0. And that
12021 ** modifications are made that move that database to state S1 and a
12022 ** changeset recorded (the "local" changeset). Then, a changeset based
12023 ** on S0 is received from another site (the "remote" changeset) and
12024 ** applied to the database. The database is then in state
12025 ** (S1+"remote"), where the exact state depends on any conflict
12026 ** resolution decisions (OMIT or REPLACE) made while applying "remote".
12027 ** Rebasing a changeset is to update it to take those conflict
12028 ** resolution decisions into account, so that the same conflicts
12029 ** do not have to be resolved elsewhere in the network.
12030 **
12031 ** For example, if both the local and remote changesets contain an
12032 ** INSERT of the same key on "CREATE TABLE t1(a PRIMARY KEY, b)":
12033 **
12034 **   local:  INSERT INTO t1 VALUES(1, 'v1');
12035 **   remote: INSERT INTO t1 VALUES(1, 'v2');
12036 **
12037 ** and the conflict resolution is REPLACE, then the INSERT change is
12038 ** removed from the local changeset (it was overridden). Or, if the
12039 ** conflict resolution was "OMIT", then the local changeset is modified
12040 ** to instead contain:
12041 **
12042 **           UPDATE t1 SET b = 'v2' WHERE a=1;
12043 **
12044 ** Changes within the local changeset are rebased as follows:
12045 **
12046 ** <dl>
12047 ** <dt>Local INSERT<dd>
12048 **   This may only conflict with a remote INSERT. If the conflict
12049 **   resolution was OMIT, then add an UPDATE change to the rebased
12050 **   changeset. Or, if the conflict resolution was REPLACE, add
12051 **   nothing to the rebased changeset.
12052 **
12053 ** <dt>Local DELETE<dd>
12054 **   This may conflict with a remote UPDATE or DELETE. In both cases the
12055 **   only possible resolution is OMIT. If the remote operation was a
12056 **   DELETE, then add no change to the rebased changeset. If the remote
12057 **   operation was an UPDATE, then the old.* fields of change are updated
12058 **   to reflect the new.* values in the UPDATE.
12059 **
12060 ** <dt>Local UPDATE<dd>
12061 **   This may conflict with a remote UPDATE or DELETE. If it conflicts
12062 **   with a DELETE, and the conflict resolution was OMIT, then the update
12063 **   is changed into an INSERT. Any undefined values in the new.* record
12064 **   from the update change are filled in using the old.* values from
12065 **   the conflicting DELETE. Or, if the conflict resolution was REPLACE,
12066 **   the UPDATE change is simply omitted from the rebased changeset.
12067 **
12068 **   If conflict is with a remote UPDATE and the resolution is OMIT, then
12069 **   the old.* values are rebased using the new.* values in the remote
12070 **   change. Or, if the resolution is REPLACE, then the change is copied
12071 **   into the rebased changeset with updates to columns also updated by
12072 **   the conflicting remote UPDATE removed. If this means no columns would
12073 **   be updated, the change is omitted.
12074 ** </dl>
12075 **
12076 ** A local change may be rebased against multiple remote changes
12077 ** simultaneously. If a single key is modified by multiple remote
12078 ** changesets, they are combined as follows before the local changeset
12079 ** is rebased:
12080 **
12081 ** <ul>
12082 **    <li> If there has been one or more REPLACE resolutions on a
12083 **         key, it is rebased according to a REPLACE.
12084 **
12085 **    <li> If there have been no REPLACE resolutions on a key, then
12086 **         the local changeset is rebased according to the most recent
12087 **         of the OMIT resolutions.
12088 ** </ul>
12089 **
12090 ** Note that conflict resolutions from multiple remote changesets are
12091 ** combined on a per-field basis, not per-row. This means that in the
12092 ** case of multiple remote UPDATE operations, some fields of a single
12093 ** local change may be rebased for REPLACE while others are rebased for
12094 ** OMIT.
12095 **
12096 ** In order to rebase a local changeset, the remote changeset must first
12097 ** be applied to the local database using sqlite3changeset_apply_v2() and
12098 ** the buffer of rebase information captured. Then:
12099 **
12100 ** <ol>
12101 **   <li> An sqlite3_rebaser object is created by calling
12102 **        sqlite3rebaser_create().
12103 **   <li> The new object is configured with the rebase buffer obtained from
12104 **        sqlite3changeset_apply_v2() by calling sqlite3rebaser_configure().
12105 **        If the local changeset is to be rebased against multiple remote
12106 **        changesets, then sqlite3rebaser_configure() should be called
12107 **        multiple times, in the same order that the multiple
12108 **        sqlite3changeset_apply_v2() calls were made.
12109 **   <li> Each local changeset is rebased by calling sqlite3rebaser_rebase().
12110 **   <li> The sqlite3_rebaser object is deleted by calling
12111 **        sqlite3rebaser_delete().
12112 ** </ol>
12113 */
12114 typedef struct sqlite3_rebaser sqlite3_rebaser;
12115 
12116 /*
12117 ** CAPI3REF: Create a changeset rebaser object.
12118 ** EXPERIMENTAL
12119 **
12120 ** Allocate a new changeset rebaser object. If successful, set (*ppNew) to
12121 ** point to the new object and return SQLITE_OK. Otherwise, if an error
12122 ** occurs, return an SQLite error code (e.g. SQLITE_NOMEM) and set (*ppNew)
12123 ** to NULL.
12124 */
12125 SQLITE_API int sqlite3rebaser_create(sqlite3_rebaser **ppNew);
12126 
12127 /*
12128 ** CAPI3REF: Configure a changeset rebaser object.
12129 ** EXPERIMENTAL
12130 **
12131 ** Configure the changeset rebaser object to rebase changesets according
12132 ** to the conflict resolutions described by buffer pRebase (size nRebase
12133 ** bytes), which must have been obtained from a previous call to
12134 ** sqlite3changeset_apply_v2().
12135 */
12136 SQLITE_API int sqlite3rebaser_configure(
12137   sqlite3_rebaser*,
12138   int nRebase, const void *pRebase
12139 );
12140 
12141 /*
12142 ** CAPI3REF: Rebase a changeset
12143 ** EXPERIMENTAL
12144 **
12145 ** Argument pIn must point to a buffer containing a changeset nIn bytes
12146 ** in size. This function allocates and populates a buffer with a copy
12147 ** of the changeset rebased according to the configuration of the
12148 ** rebaser object passed as the first argument. If successful, (*ppOut)
12149 ** is set to point to the new buffer containing the rebased changeset and
12150 ** (*pnOut) to its size in bytes and SQLITE_OK returned. It is the
12151 ** responsibility of the caller to eventually free the new buffer using
12152 ** sqlite3_free(). Otherwise, if an error occurs, (*ppOut) and (*pnOut)
12153 ** are set to zero and an SQLite error code returned.
12154 */
12155 SQLITE_API int sqlite3rebaser_rebase(
12156   sqlite3_rebaser*,
12157   int nIn, const void *pIn,
12158   int *pnOut, void **ppOut
12159 );
12160 
12161 /*
12162 ** CAPI3REF: Delete a changeset rebaser object.
12163 ** EXPERIMENTAL
12164 **
12165 ** Delete the changeset rebaser object and all associated resources. There
12166 ** should be one call to this function for each successful invocation
12167 ** of sqlite3rebaser_create().
12168 */
12169 SQLITE_API void sqlite3rebaser_delete(sqlite3_rebaser *p);
12170 
12171 /*
12172 ** CAPI3REF: Streaming Versions of API functions.
12173 **
12174 ** The six streaming API xxx_strm() functions serve similar purposes to the
12175 ** corresponding non-streaming API functions:
12176 **
12177 ** <table border=1 style="margin-left:8ex;margin-right:8ex">
12178 **   <tr><th>Streaming function<th>Non-streaming equivalent</th>
12179 **   <tr><td>sqlite3changeset_apply_strm<td>[sqlite3changeset_apply]
12180 **   <tr><td>sqlite3changeset_apply_strm_v2<td>[sqlite3changeset_apply_v2]
12181 **   <tr><td>sqlite3changeset_concat_strm<td>[sqlite3changeset_concat]
12182 **   <tr><td>sqlite3changeset_invert_strm<td>[sqlite3changeset_invert]
12183 **   <tr><td>sqlite3changeset_start_strm<td>[sqlite3changeset_start]
12184 **   <tr><td>sqlite3session_changeset_strm<td>[sqlite3session_changeset]
12185 **   <tr><td>sqlite3session_patchset_strm<td>[sqlite3session_patchset]
12186 ** </table>
12187 **
12188 ** Non-streaming functions that accept changesets (or patchsets) as input
12189 ** require that the entire changeset be stored in a single buffer in memory.
12190 ** Similarly, those that return a changeset or patchset do so by returning
12191 ** a pointer to a single large buffer allocated using sqlite3_malloc().
12192 ** Normally this is convenient. However, if an application running in a
12193 ** low-memory environment is required to handle very large changesets, the
12194 ** large contiguous memory allocations required can become onerous.
12195 **
12196 ** In order to avoid this problem, instead of a single large buffer, input
12197 ** is passed to a streaming API functions by way of a callback function that
12198 ** the sessions module invokes to incrementally request input data as it is
12199 ** required. In all cases, a pair of API function parameters such as
12200 **
12201 **  <pre>
12202 **  &nbsp;     int nChangeset,
12203 **  &nbsp;     void *pChangeset,
12204 **  </pre>
12205 **
12206 ** Is replaced by:
12207 **
12208 **  <pre>
12209 **  &nbsp;     int (*xInput)(void *pIn, void *pData, int *pnData),
12210 **  &nbsp;     void *pIn,
12211 **  </pre>
12212 **
12213 ** Each time the xInput callback is invoked by the sessions module, the first
12214 ** argument passed is a copy of the supplied pIn context pointer. The second
12215 ** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no
12216 ** error occurs the xInput method should copy up to (*pnData) bytes of data
12217 ** into the buffer and set (*pnData) to the actual number of bytes copied
12218 ** before returning SQLITE_OK. If the input is completely exhausted, (*pnData)
12219 ** should be set to zero to indicate this. Or, if an error occurs, an SQLite
12220 ** error code should be returned. In all cases, if an xInput callback returns
12221 ** an error, all processing is abandoned and the streaming API function
12222 ** returns a copy of the error code to the caller.
12223 **
12224 ** In the case of sqlite3changeset_start_strm(), the xInput callback may be
12225 ** invoked by the sessions module at any point during the lifetime of the
12226 ** iterator. If such an xInput callback returns an error, the iterator enters
12227 ** an error state, whereby all subsequent calls to iterator functions
12228 ** immediately fail with the same error code as returned by xInput.
12229 **
12230 ** Similarly, streaming API functions that return changesets (or patchsets)
12231 ** return them in chunks by way of a callback function instead of via a
12232 ** pointer to a single large buffer. In this case, a pair of parameters such
12233 ** as:
12234 **
12235 **  <pre>
12236 **  &nbsp;     int *pnChangeset,
12237 **  &nbsp;     void **ppChangeset,
12238 **  </pre>
12239 **
12240 ** Is replaced by:
12241 **
12242 **  <pre>
12243 **  &nbsp;     int (*xOutput)(void *pOut, const void *pData, int nData),
12244 **  &nbsp;     void *pOut
12245 **  </pre>
12246 **
12247 ** The xOutput callback is invoked zero or more times to return data to
12248 ** the application. The first parameter passed to each call is a copy of the
12249 ** pOut pointer supplied by the application. The second parameter, pData,
12250 ** points to a buffer nData bytes in size containing the chunk of output
12251 ** data being returned. If the xOutput callback successfully processes the
12252 ** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
12253 ** it should return some other SQLite error code. In this case processing
12254 ** is immediately abandoned and the streaming API function returns a copy
12255 ** of the xOutput error code to the application.
12256 **
12257 ** The sessions module never invokes an xOutput callback with the third
12258 ** parameter set to a value less than or equal to zero. Other than this,
12259 ** no guarantees are made as to the size of the chunks of data returned.
12260 */
12261 SQLITE_API int sqlite3changeset_apply_strm(
12262   sqlite3 *db,                    /* Apply change to "main" db of this handle */
12263   int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
12264   void *pIn,                                          /* First arg for xInput */
12265   int(*xFilter)(
12266     void *pCtx,                   /* Copy of sixth arg to _apply() */
12267     const char *zTab              /* Table name */
12268   ),
12269   int(*xConflict)(
12270     void *pCtx,                   /* Copy of sixth arg to _apply() */
12271     int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
12272     sqlite3_changeset_iter *p     /* Handle describing change and conflict */
12273   ),
12274   void *pCtx                      /* First argument passed to xConflict */
12275 );
12276 SQLITE_API int sqlite3changeset_apply_v2_strm(
12277   sqlite3 *db,                    /* Apply change to "main" db of this handle */
12278   int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
12279   void *pIn,                                          /* First arg for xInput */
12280   int(*xFilter)(
12281     void *pCtx,                   /* Copy of sixth arg to _apply() */
12282     const char *zTab              /* Table name */
12283   ),
12284   int(*xConflict)(
12285     void *pCtx,                   /* Copy of sixth arg to _apply() */
12286     int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
12287     sqlite3_changeset_iter *p     /* Handle describing change and conflict */
12288   ),
12289   void *pCtx,                     /* First argument passed to xConflict */
12290   void **ppRebase, int *pnRebase,
12291   int flags
12292 );
12293 SQLITE_API int sqlite3changeset_concat_strm(
12294   int (*xInputA)(void *pIn, void *pData, int *pnData),
12295   void *pInA,
12296   int (*xInputB)(void *pIn, void *pData, int *pnData),
12297   void *pInB,
12298   int (*xOutput)(void *pOut, const void *pData, int nData),
12299   void *pOut
12300 );
12301 SQLITE_API int sqlite3changeset_invert_strm(
12302   int (*xInput)(void *pIn, void *pData, int *pnData),
12303   void *pIn,
12304   int (*xOutput)(void *pOut, const void *pData, int nData),
12305   void *pOut
12306 );
12307 SQLITE_API int sqlite3changeset_start_strm(
12308   sqlite3_changeset_iter **pp,
12309   int (*xInput)(void *pIn, void *pData, int *pnData),
12310   void *pIn
12311 );
12312 SQLITE_API int sqlite3changeset_start_v2_strm(
12313   sqlite3_changeset_iter **pp,
12314   int (*xInput)(void *pIn, void *pData, int *pnData),
12315   void *pIn,
12316   int flags
12317 );
12318 SQLITE_API int sqlite3session_changeset_strm(
12319   sqlite3_session *pSession,
12320   int (*xOutput)(void *pOut, const void *pData, int nData),
12321   void *pOut
12322 );
12323 SQLITE_API int sqlite3session_patchset_strm(
12324   sqlite3_session *pSession,
12325   int (*xOutput)(void *pOut, const void *pData, int nData),
12326   void *pOut
12327 );
12328 SQLITE_API int sqlite3changegroup_add_strm(sqlite3_changegroup*,
12329     int (*xInput)(void *pIn, void *pData, int *pnData),
12330     void *pIn
12331 );
12332 SQLITE_API int sqlite3changegroup_output_strm(sqlite3_changegroup*,
12333     int (*xOutput)(void *pOut, const void *pData, int nData),
12334     void *pOut
12335 );
12336 SQLITE_API int sqlite3rebaser_rebase_strm(
12337   sqlite3_rebaser *pRebaser,
12338   int (*xInput)(void *pIn, void *pData, int *pnData),
12339   void *pIn,
12340   int (*xOutput)(void *pOut, const void *pData, int nData),
12341   void *pOut
12342 );
12343 
12344 /*
12345 ** CAPI3REF: Configure global parameters
12346 **
12347 ** The sqlite3session_config() interface is used to make global configuration
12348 ** changes to the sessions module in order to tune it to the specific needs
12349 ** of the application.
12350 **
12351 ** The sqlite3session_config() interface is not threadsafe. If it is invoked
12352 ** while any other thread is inside any other sessions method then the
12353 ** results are undefined. Furthermore, if it is invoked after any sessions
12354 ** related objects have been created, the results are also undefined.
12355 **
12356 ** The first argument to the sqlite3session_config() function must be one
12357 ** of the SQLITE_SESSION_CONFIG_XXX constants defined below. The
12358 ** interpretation of the (void*) value passed as the second parameter and
12359 ** the effect of calling this function depends on the value of the first
12360 ** parameter.
12361 **
12362 ** <dl>
12363 ** <dt>SQLITE_SESSION_CONFIG_STRMSIZE<dd>
12364 **    By default, the sessions module streaming interfaces attempt to input
12365 **    and output data in approximately 1 KiB chunks. This operand may be used
12366 **    to set and query the value of this configuration setting. The pointer
12367 **    passed as the second argument must point to a value of type (int).
12368 **    If this value is greater than 0, it is used as the new streaming data
12369 **    chunk size for both input and output. Before returning, the (int) value
12370 **    pointed to by pArg is set to the final value of the streaming interface
12371 **    chunk size.
12372 ** </dl>
12373 **
12374 ** This function returns SQLITE_OK if successful, or an SQLite error code
12375 ** otherwise.
12376 */
12377 SQLITE_API int sqlite3session_config(int op, void *pArg);
12378 
12379 /*
12380 ** CAPI3REF: Values for sqlite3session_config().
12381 */
12382 #define SQLITE_SESSION_CONFIG_STRMSIZE 1
12383 
12384 /*
12385 ** Make sure we can call this stuff from C++.
12386 */
12387 #ifdef __cplusplus
12388 }
12389 #endif
12390 
12391 #endif  /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
12392 
12393 /******** End of sqlite3session.h *********/
12394 /******** Begin file fts5.h *********/
12395 /*
12396 ** 2014 May 31
12397 **
12398 ** The author disclaims copyright to this source code.  In place of
12399 ** a legal notice, here is a blessing:
12400 **
12401 **    May you do good and not evil.
12402 **    May you find forgiveness for yourself and forgive others.
12403 **    May you share freely, never taking more than you give.
12404 **
12405 ******************************************************************************
12406 **
12407 ** Interfaces to extend FTS5. Using the interfaces defined in this file,
12408 ** FTS5 may be extended with:
12409 **
12410 **     * custom tokenizers, and
12411 **     * custom auxiliary functions.
12412 */
12413 
12414 
12415 #ifndef _FTS5_H
12416 #define _FTS5_H
12417 
12418 
12419 #ifdef __cplusplus
12420 extern "C" {
12421 #endif
12422 
12423 /*************************************************************************
12424 ** CUSTOM AUXILIARY FUNCTIONS
12425 **
12426 ** Virtual table implementations may overload SQL functions by implementing
12427 ** the sqlite3_module.xFindFunction() method.
12428 */
12429 
12430 typedef struct Fts5ExtensionApi Fts5ExtensionApi;
12431 typedef struct Fts5Context Fts5Context;
12432 typedef struct Fts5PhraseIter Fts5PhraseIter;
12433 
12434 typedef void (*fts5_extension_function)(
12435   const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
12436   Fts5Context *pFts,              /* First arg to pass to pApi functions */
12437   sqlite3_context *pCtx,          /* Context for returning result/error */
12438   int nVal,                       /* Number of values in apVal[] array */
12439   sqlite3_value **apVal           /* Array of trailing arguments */
12440 );
12441 
12442 struct Fts5PhraseIter {
12443   const unsigned char *a;
12444   const unsigned char *b;
12445 };
12446 
12447 /*
12448 ** EXTENSION API FUNCTIONS
12449 **
12450 ** xUserData(pFts):
12451 **   Return a copy of the context pointer the extension function was
12452 **   registered with.
12453 **
12454 ** xColumnTotalSize(pFts, iCol, pnToken):
12455 **   If parameter iCol is less than zero, set output variable *pnToken
12456 **   to the total number of tokens in the FTS5 table. Or, if iCol is
12457 **   non-negative but less than the number of columns in the table, return
12458 **   the total number of tokens in column iCol, considering all rows in
12459 **   the FTS5 table.
12460 **
12461 **   If parameter iCol is greater than or equal to the number of columns
12462 **   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
12463 **   an OOM condition or IO error), an appropriate SQLite error code is
12464 **   returned.
12465 **
12466 ** xColumnCount(pFts):
12467 **   Return the number of columns in the table.
12468 **
12469 ** xColumnSize(pFts, iCol, pnToken):
12470 **   If parameter iCol is less than zero, set output variable *pnToken
12471 **   to the total number of tokens in the current row. Or, if iCol is
12472 **   non-negative but less than the number of columns in the table, set
12473 **   *pnToken to the number of tokens in column iCol of the current row.
12474 **
12475 **   If parameter iCol is greater than or equal to the number of columns
12476 **   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
12477 **   an OOM condition or IO error), an appropriate SQLite error code is
12478 **   returned.
12479 **
12480 **   This function may be quite inefficient if used with an FTS5 table
12481 **   created with the "columnsize=0" option.
12482 **
12483 ** xColumnText:
12484 **   This function attempts to retrieve the text of column iCol of the
12485 **   current document. If successful, (*pz) is set to point to a buffer
12486 **   containing the text in utf-8 encoding, (*pn) is set to the size in bytes
12487 **   (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
12488 **   if an error occurs, an SQLite error code is returned and the final values
12489 **   of (*pz) and (*pn) are undefined.
12490 **
12491 ** xPhraseCount:
12492 **   Returns the number of phrases in the current query expression.
12493 **
12494 ** xPhraseSize:
12495 **   Returns the number of tokens in phrase iPhrase of the query. Phrases
12496 **   are numbered starting from zero.
12497 **
12498 ** xInstCount:
12499 **   Set *pnInst to the total number of occurrences of all phrases within
12500 **   the query within the current row. Return SQLITE_OK if successful, or
12501 **   an error code (i.e. SQLITE_NOMEM) if an error occurs.
12502 **
12503 **   This API can be quite slow if used with an FTS5 table created with the
12504 **   "detail=none" or "detail=column" option. If the FTS5 table is created
12505 **   with either "detail=none" or "detail=column" and "content=" option
12506 **   (i.e. if it is a contentless table), then this API always returns 0.
12507 **
12508 ** xInst:
12509 **   Query for the details of phrase match iIdx within the current row.
12510 **   Phrase matches are numbered starting from zero, so the iIdx argument
12511 **   should be greater than or equal to zero and smaller than the value
12512 **   output by xInstCount().
12513 **
12514 **   Usually, output parameter *piPhrase is set to the phrase number, *piCol
12515 **   to the column in which it occurs and *piOff the token offset of the
12516 **   first token of the phrase. Returns SQLITE_OK if successful, or an error
12517 **   code (i.e. SQLITE_NOMEM) if an error occurs.
12518 **
12519 **   This API can be quite slow if used with an FTS5 table created with the
12520 **   "detail=none" or "detail=column" option.
12521 **
12522 ** xRowid:
12523 **   Returns the rowid of the current row.
12524 **
12525 ** xTokenize:
12526 **   Tokenize text using the tokenizer belonging to the FTS5 table.
12527 **
12528 ** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
12529 **   This API function is used to query the FTS table for phrase iPhrase
12530 **   of the current query. Specifically, a query equivalent to:
12531 **
12532 **       ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
12533 **
12534 **   with $p set to a phrase equivalent to the phrase iPhrase of the
12535 **   current query is executed. Any column filter that applies to
12536 **   phrase iPhrase of the current query is included in $p. For each
12537 **   row visited, the callback function passed as the fourth argument
12538 **   is invoked. The context and API objects passed to the callback
12539 **   function may be used to access the properties of each matched row.
12540 **   Invoking Api.xUserData() returns a copy of the pointer passed as
12541 **   the third argument to pUserData.
12542 **
12543 **   If the callback function returns any value other than SQLITE_OK, the
12544 **   query is abandoned and the xQueryPhrase function returns immediately.
12545 **   If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
12546 **   Otherwise, the error code is propagated upwards.
12547 **
12548 **   If the query runs to completion without incident, SQLITE_OK is returned.
12549 **   Or, if some error occurs before the query completes or is aborted by
12550 **   the callback, an SQLite error code is returned.
12551 **
12552 **
12553 ** xSetAuxdata(pFts5, pAux, xDelete)
12554 **
12555 **   Save the pointer passed as the second argument as the extension function's
12556 **   "auxiliary data". The pointer may then be retrieved by the current or any
12557 **   future invocation of the same fts5 extension function made as part of
12558 **   the same MATCH query using the xGetAuxdata() API.
12559 **
12560 **   Each extension function is allocated a single auxiliary data slot for
12561 **   each FTS query (MATCH expression). If the extension function is invoked
12562 **   more than once for a single FTS query, then all invocations share a
12563 **   single auxiliary data context.
12564 **
12565 **   If there is already an auxiliary data pointer when this function is
12566 **   invoked, then it is replaced by the new pointer. If an xDelete callback
12567 **   was specified along with the original pointer, it is invoked at this
12568 **   point.
12569 **
12570 **   The xDelete callback, if one is specified, is also invoked on the
12571 **   auxiliary data pointer after the FTS5 query has finished.
12572 **
12573 **   If an error (e.g. an OOM condition) occurs within this function,
12574 **   the auxiliary data is set to NULL and an error code returned. If the
12575 **   xDelete parameter was not NULL, it is invoked on the auxiliary data
12576 **   pointer before returning.
12577 **
12578 **
12579 ** xGetAuxdata(pFts5, bClear)
12580 **
12581 **   Returns the current auxiliary data pointer for the fts5 extension
12582 **   function. See the xSetAuxdata() method for details.
12583 **
12584 **   If the bClear argument is non-zero, then the auxiliary data is cleared
12585 **   (set to NULL) before this function returns. In this case the xDelete,
12586 **   if any, is not invoked.
12587 **
12588 **
12589 ** xRowCount(pFts5, pnRow)
12590 **
12591 **   This function is used to retrieve the total number of rows in the table.
12592 **   In other words, the same value that would be returned by:
12593 **
12594 **        SELECT count(*) FROM ftstable;
12595 **
12596 ** xPhraseFirst()
12597 **   This function is used, along with type Fts5PhraseIter and the xPhraseNext
12598 **   method, to iterate through all instances of a single query phrase within
12599 **   the current row. This is the same information as is accessible via the
12600 **   xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
12601 **   to use, this API may be faster under some circumstances. To iterate
12602 **   through instances of phrase iPhrase, use the following code:
12603 **
12604 **       Fts5PhraseIter iter;
12605 **       int iCol, iOff;
12606 **       for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
12607 **           iCol>=0;
12608 **           pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
12609 **       ){
12610 **         // An instance of phrase iPhrase at offset iOff of column iCol
12611 **       }
12612 **
12613 **   The Fts5PhraseIter structure is defined above. Applications should not
12614 **   modify this structure directly - it should only be used as shown above
12615 **   with the xPhraseFirst() and xPhraseNext() API methods (and by
12616 **   xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
12617 **
12618 **   This API can be quite slow if used with an FTS5 table created with the
12619 **   "detail=none" or "detail=column" option. If the FTS5 table is created
12620 **   with either "detail=none" or "detail=column" and "content=" option
12621 **   (i.e. if it is a contentless table), then this API always iterates
12622 **   through an empty set (all calls to xPhraseFirst() set iCol to -1).
12623 **
12624 ** xPhraseNext()
12625 **   See xPhraseFirst above.
12626 **
12627 ** xPhraseFirstColumn()
12628 **   This function and xPhraseNextColumn() are similar to the xPhraseFirst()
12629 **   and xPhraseNext() APIs described above. The difference is that instead
12630 **   of iterating through all instances of a phrase in the current row, these
12631 **   APIs are used to iterate through the set of columns in the current row
12632 **   that contain one or more instances of a specified phrase. For example:
12633 **
12634 **       Fts5PhraseIter iter;
12635 **       int iCol;
12636 **       for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
12637 **           iCol>=0;
12638 **           pApi->xPhraseNextColumn(pFts, &iter, &iCol)
12639 **       ){
12640 **         // Column iCol contains at least one instance of phrase iPhrase
12641 **       }
12642 **
12643 **   This API can be quite slow if used with an FTS5 table created with the
12644 **   "detail=none" option. If the FTS5 table is created with either
12645 **   "detail=none" "content=" option (i.e. if it is a contentless table),
12646 **   then this API always iterates through an empty set (all calls to
12647 **   xPhraseFirstColumn() set iCol to -1).
12648 **
12649 **   The information accessed using this API and its companion
12650 **   xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
12651 **   (or xInst/xInstCount). The chief advantage of this API is that it is
12652 **   significantly more efficient than those alternatives when used with
12653 **   "detail=column" tables.
12654 **
12655 ** xPhraseNextColumn()
12656 **   See xPhraseFirstColumn above.
12657 */
12658 struct Fts5ExtensionApi {
12659   int iVersion;                   /* Currently always set to 3 */
12660 
12661   void *(*xUserData)(Fts5Context*);
12662 
12663   int (*xColumnCount)(Fts5Context*);
12664   int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
12665   int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
12666 
12667   int (*xTokenize)(Fts5Context*,
12668     const char *pText, int nText, /* Text to tokenize */
12669     void *pCtx,                   /* Context passed to xToken() */
12670     int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
12671   );
12672 
12673   int (*xPhraseCount)(Fts5Context*);
12674   int (*xPhraseSize)(Fts5Context*, int iPhrase);
12675 
12676   int (*xInstCount)(Fts5Context*, int *pnInst);
12677   int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
12678 
12679   sqlite3_int64 (*xRowid)(Fts5Context*);
12680   int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
12681   int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
12682 
12683   int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
12684     int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
12685   );
12686   int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
12687   void *(*xGetAuxdata)(Fts5Context*, int bClear);
12688 
12689   int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
12690   void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
12691 
12692   int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
12693   void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
12694 };
12695 
12696 /*
12697 ** CUSTOM AUXILIARY FUNCTIONS
12698 *************************************************************************/
12699 
12700 /*************************************************************************
12701 ** CUSTOM TOKENIZERS
12702 **
12703 ** Applications may also register custom tokenizer types. A tokenizer
12704 ** is registered by providing fts5 with a populated instance of the
12705 ** following structure. All structure methods must be defined, setting
12706 ** any member of the fts5_tokenizer struct to NULL leads to undefined
12707 ** behaviour. The structure methods are expected to function as follows:
12708 **
12709 ** xCreate:
12710 **   This function is used to allocate and initialize a tokenizer instance.
12711 **   A tokenizer instance is required to actually tokenize text.
12712 **
12713 **   The first argument passed to this function is a copy of the (void*)
12714 **   pointer provided by the application when the fts5_tokenizer object
12715 **   was registered with FTS5 (the third argument to xCreateTokenizer()).
12716 **   The second and third arguments are an array of nul-terminated strings
12717 **   containing the tokenizer arguments, if any, specified following the
12718 **   tokenizer name as part of the CREATE VIRTUAL TABLE statement used
12719 **   to create the FTS5 table.
12720 **
12721 **   The final argument is an output variable. If successful, (*ppOut)
12722 **   should be set to point to the new tokenizer handle and SQLITE_OK
12723 **   returned. If an error occurs, some value other than SQLITE_OK should
12724 **   be returned. In this case, fts5 assumes that the final value of *ppOut
12725 **   is undefined.
12726 **
12727 ** xDelete:
12728 **   This function is invoked to delete a tokenizer handle previously
12729 **   allocated using xCreate(). Fts5 guarantees that this function will
12730 **   be invoked exactly once for each successful call to xCreate().
12731 **
12732 ** xTokenize:
12733 **   This function is expected to tokenize the nText byte string indicated
12734 **   by argument pText. pText may or may not be nul-terminated. The first
12735 **   argument passed to this function is a pointer to an Fts5Tokenizer object
12736 **   returned by an earlier call to xCreate().
12737 **
12738 **   The second argument indicates the reason that FTS5 is requesting
12739 **   tokenization of the supplied text. This is always one of the following
12740 **   four values:
12741 **
12742 **   <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
12743 **            or removed from the FTS table. The tokenizer is being invoked to
12744 **            determine the set of tokens to add to (or delete from) the
12745 **            FTS index.
12746 **
12747 **       <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
12748 **            against the FTS index. The tokenizer is being called to tokenize
12749 **            a bareword or quoted string specified as part of the query.
12750 **
12751 **       <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
12752 **            FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
12753 **            followed by a "*" character, indicating that the last token
12754 **            returned by the tokenizer will be treated as a token prefix.
12755 **
12756 **       <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
12757 **            satisfy an fts5_api.xTokenize() request made by an auxiliary
12758 **            function. Or an fts5_api.xColumnSize() request made by the same
12759 **            on a columnsize=0 database.
12760 **   </ul>
12761 **
12762 **   For each token in the input string, the supplied callback xToken() must
12763 **   be invoked. The first argument to it should be a copy of the pointer
12764 **   passed as the second argument to xTokenize(). The third and fourth
12765 **   arguments are a pointer to a buffer containing the token text, and the
12766 **   size of the token in bytes. The 4th and 5th arguments are the byte offsets
12767 **   of the first byte of and first byte immediately following the text from
12768 **   which the token is derived within the input.
12769 **
12770 **   The second argument passed to the xToken() callback ("tflags") should
12771 **   normally be set to 0. The exception is if the tokenizer supports
12772 **   synonyms. In this case see the discussion below for details.
12773 **
12774 **   FTS5 assumes the xToken() callback is invoked for each token in the
12775 **   order that they occur within the input text.
12776 **
12777 **   If an xToken() callback returns any value other than SQLITE_OK, then
12778 **   the tokenization should be abandoned and the xTokenize() method should
12779 **   immediately return a copy of the xToken() return value. Or, if the
12780 **   input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
12781 **   if an error occurs with the xTokenize() implementation itself, it
12782 **   may abandon the tokenization and return any error code other than
12783 **   SQLITE_OK or SQLITE_DONE.
12784 **
12785 ** SYNONYM SUPPORT
12786 **
12787 **   Custom tokenizers may also support synonyms. Consider a case in which a
12788 **   user wishes to query for a phrase such as "first place". Using the
12789 **   built-in tokenizers, the FTS5 query 'first + place' will match instances
12790 **   of "first place" within the document set, but not alternative forms
12791 **   such as "1st place". In some applications, it would be better to match
12792 **   all instances of "first place" or "1st place" regardless of which form
12793 **   the user specified in the MATCH query text.
12794 **
12795 **   There are several ways to approach this in FTS5:
12796 **
12797 **   <ol><li> By mapping all synonyms to a single token. In this case, using
12798 **            the above example, this means that the tokenizer returns the
12799 **            same token for inputs "first" and "1st". Say that token is in
12800 **            fact "first", so that when the user inserts the document "I won
12801 **            1st place" entries are added to the index for tokens "i", "won",
12802 **            "first" and "place". If the user then queries for '1st + place',
12803 **            the tokenizer substitutes "first" for "1st" and the query works
12804 **            as expected.
12805 **
12806 **       <li> By querying the index for all synonyms of each query term
12807 **            separately. In this case, when tokenizing query text, the
12808 **            tokenizer may provide multiple synonyms for a single term
12809 **            within the document. FTS5 then queries the index for each
12810 **            synonym individually. For example, faced with the query:
12811 **
12812 **   <codeblock>
12813 **     ... MATCH 'first place'</codeblock>
12814 **
12815 **            the tokenizer offers both "1st" and "first" as synonyms for the
12816 **            first token in the MATCH query and FTS5 effectively runs a query
12817 **            similar to:
12818 **
12819 **   <codeblock>
12820 **     ... MATCH '(first OR 1st) place'</codeblock>
12821 **
12822 **            except that, for the purposes of auxiliary functions, the query
12823 **            still appears to contain just two phrases - "(first OR 1st)"
12824 **            being treated as a single phrase.
12825 **
12826 **       <li> By adding multiple synonyms for a single term to the FTS index.
12827 **            Using this method, when tokenizing document text, the tokenizer
12828 **            provides multiple synonyms for each token. So that when a
12829 **            document such as "I won first place" is tokenized, entries are
12830 **            added to the FTS index for "i", "won", "first", "1st" and
12831 **            "place".
12832 **
12833 **            This way, even if the tokenizer does not provide synonyms
12834 **            when tokenizing query text (it should not - to do so would be
12835 **            inefficient), it doesn't matter if the user queries for
12836 **            'first + place' or '1st + place', as there are entries in the
12837 **            FTS index corresponding to both forms of the first token.
12838 **   </ol>
12839 **
12840 **   Whether it is parsing document or query text, any call to xToken that
12841 **   specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
12842 **   is considered to supply a synonym for the previous token. For example,
12843 **   when parsing the document "I won first place", a tokenizer that supports
12844 **   synonyms would call xToken() 5 times, as follows:
12845 **
12846 **   <codeblock>
12847 **       xToken(pCtx, 0, "i",                      1,  0,  1);
12848 **       xToken(pCtx, 0, "won",                    3,  2,  5);
12849 **       xToken(pCtx, 0, "first",                  5,  6, 11);
12850 **       xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3,  6, 11);
12851 **       xToken(pCtx, 0, "place",                  5, 12, 17);
12852 **</codeblock>
12853 **
12854 **   It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
12855 **   xToken() is called. Multiple synonyms may be specified for a single token
12856 **   by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
12857 **   There is no limit to the number of synonyms that may be provided for a
12858 **   single token.
12859 **
12860 **   In many cases, method (1) above is the best approach. It does not add
12861 **   extra data to the FTS index or require FTS5 to query for multiple terms,
12862 **   so it is efficient in terms of disk space and query speed. However, it
12863 **   does not support prefix queries very well. If, as suggested above, the
12864 **   token "first" is substituted for "1st" by the tokenizer, then the query:
12865 **
12866 **   <codeblock>
12867 **     ... MATCH '1s*'</codeblock>
12868 **
12869 **   will not match documents that contain the token "1st" (as the tokenizer
12870 **   will probably not map "1s" to any prefix of "first").
12871 **
12872 **   For full prefix support, method (3) may be preferred. In this case,
12873 **   because the index contains entries for both "first" and "1st", prefix
12874 **   queries such as 'fi*' or '1s*' will match correctly. However, because
12875 **   extra entries are added to the FTS index, this method uses more space
12876 **   within the database.
12877 **
12878 **   Method (2) offers a midpoint between (1) and (3). Using this method,
12879 **   a query such as '1s*' will match documents that contain the literal
12880 **   token "1st", but not "first" (assuming the tokenizer is not able to
12881 **   provide synonyms for prefixes). However, a non-prefix query like '1st'
12882 **   will match against "1st" and "first". This method does not require
12883 **   extra disk space, as no extra entries are added to the FTS index.
12884 **   On the other hand, it may require more CPU cycles to run MATCH queries,
12885 **   as separate queries of the FTS index are required for each synonym.
12886 **
12887 **   When using methods (2) or (3), it is important that the tokenizer only
12888 **   provide synonyms when tokenizing document text (method (2)) or query
12889 **   text (method (3)), not both. Doing so will not cause any errors, but is
12890 **   inefficient.
12891 */
12892 typedef struct Fts5Tokenizer Fts5Tokenizer;
12893 typedef struct fts5_tokenizer fts5_tokenizer;
12894 struct fts5_tokenizer {
12895   int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
12896   void (*xDelete)(Fts5Tokenizer*);
12897   int (*xTokenize)(Fts5Tokenizer*,
12898       void *pCtx,
12899       int flags,            /* Mask of FTS5_TOKENIZE_* flags */
12900       const char *pText, int nText,
12901       int (*xToken)(
12902         void *pCtx,         /* Copy of 2nd argument to xTokenize() */
12903         int tflags,         /* Mask of FTS5_TOKEN_* flags */
12904         const char *pToken, /* Pointer to buffer containing token */
12905         int nToken,         /* Size of token in bytes */
12906         int iStart,         /* Byte offset of token within input text */
12907         int iEnd            /* Byte offset of end of token within input text */
12908       )
12909   );
12910 };
12911 
12912 /* Flags that may be passed as the third argument to xTokenize() */
12913 #define FTS5_TOKENIZE_QUERY     0x0001
12914 #define FTS5_TOKENIZE_PREFIX    0x0002
12915 #define FTS5_TOKENIZE_DOCUMENT  0x0004
12916 #define FTS5_TOKENIZE_AUX       0x0008
12917 
12918 /* Flags that may be passed by the tokenizer implementation back to FTS5
12919 ** as the third argument to the supplied xToken callback. */
12920 #define FTS5_TOKEN_COLOCATED    0x0001      /* Same position as prev. token */
12921 
12922 /*
12923 ** END OF CUSTOM TOKENIZERS
12924 *************************************************************************/
12925 
12926 /*************************************************************************
12927 ** FTS5 EXTENSION REGISTRATION API
12928 */
12929 typedef struct fts5_api fts5_api;
12930 struct fts5_api {
12931   int iVersion;                   /* Currently always set to 2 */
12932 
12933   /* Create a new tokenizer */
12934   int (*xCreateTokenizer)(
12935     fts5_api *pApi,
12936     const char *zName,
12937     void *pContext,
12938     fts5_tokenizer *pTokenizer,
12939     void (*xDestroy)(void*)
12940   );
12941 
12942   /* Find an existing tokenizer */
12943   int (*xFindTokenizer)(
12944     fts5_api *pApi,
12945     const char *zName,
12946     void **ppContext,
12947     fts5_tokenizer *pTokenizer
12948   );
12949 
12950   /* Create a new auxiliary function */
12951   int (*xCreateFunction)(
12952     fts5_api *pApi,
12953     const char *zName,
12954     void *pContext,
12955     fts5_extension_function xFunction,
12956     void (*xDestroy)(void*)
12957   );
12958 };
12959 
12960 /*
12961 ** END OF REGISTRATION API
12962 *************************************************************************/
12963 
12964 #ifdef __cplusplus
12965 }  /* end of the 'extern "C"' block */
12966 #endif
12967 
12968 #endif /* _FTS5_H */
12969 
12970 /******** End of fts5.h *********/
12971